Patent Publication Number: US-7223690-B2

Title: Substrate processing method

Description:
This is a Divisional Application of U.S. patent application Ser. No. 10/787,218, filed Feb. 27, 2004 now U.S. Pat. No. 6,828,225 which is a continuation of U.S. patent application Ser. No. 10/182,835, now U.S. Pat. No. 6,790,763, which is the national phase of PCT/JP01/10590, filed Dec. 4, 2001. 
    
    
     TECHNICAL FIELD 
     This invention relates to a substrate processing method, and more particularly, to those used to fill fine recesses formed on the surface of a semiconductor substrate with copper, thereby forming a copper interconnection pattern. 
     BACKGROUND ART 
     In recent years, with the increased throughput and the higher integration of semiconductor chips, moves to use copper (Cu) with low electric resistivity and high electromigration resistance as a metallic material for forming an interconnection circuit on a semiconductor substrate, instead of aluminum or aluminum alloy, have become noticeable. A copper interconnection of this type is generally formed by filling fine recesses formed on the surface of the substrate with copper. Methods for forming the copper interconnection include CVD, sputtering, and plating. 
       FIGS. 62A to 62C  show an example to form a copper interconnection by copper plating in the sequence of steps. As shown in  FIG. 62A , an insulating film  2  of SiO 2  is deposited on a conductive layer  1   a  on a semiconductor substrate  1  having formed a semiconductor device. A contact hole  3  and a trench  4  for an interconnection are formed in the insulating film  2  by lithography and etching technology. A barrier layer  5  of TaN or the like is formed on the contact hole  3  and the trench  4 , and a copper seed layer  7  is further formed thereon as a power supply layer for electroplating. 
     As shown in  FIG. 62B , copper plating is applied to the surface of a semiconductor substrate W to fill copper into the contact hole  3  and the trench  4  of the semiconductor substrate  1  and also deposit a copper film  6  on the insulating film  2 . Then, the copper film  6  and the barrier layer  5  on the insulating film  2  is removed by chemical mechanical polishing (CMP), thus making the surface of the copper film  6  filled into the contact hole  3  and the trench  4  for an interconnection lie flush with the surface of the insulating film  2 . In this manner, an interconnection composed of the plated copper film  6  is formed as shown in  FIG. 62C . 
       FIG. 63  shows the entire constitution of a substrate processing apparatus for performing the above series of interconnection formation steps in a clean room. In the clean room, an insulating film forming device  10 , a lithography and etching device  12 , a barrier layer forming device  14 , a copper seed layer forming device  26 , a copper plating device  18 , and a CMP device  20  are housed. The substrate W having the insulating film  2  formed by the insulating film forming device  10  is accommodated into a substrate cassette  22 , and transported to the lithography and etching device  12  for a subsequent step. The substrate W having the contact hole  3  and the trench  4  for an interconnection formed in the lithography and etching device  12  is transported, while being housed in the substrate cassette  22 , to the barrier layer forming device  14  for a subsequent step. The substrate W thus processed in the respective devices is transported, while being accommodated in the substrate cassette  22 , to subsequent steps, whereby the series of interconnection formation steps are sequentially performed. 
       FIG. 64  schematically shows a conventional general configuration of a copper plating device for use in the above type of copper plating. This plating device includes a cylindrical plating tank  602  opening upward and holding a plating liquid  600  inside, and a rotatable substrate holder  604  adapted to detachably hold a substrate W, such as a substrate, so as to face downward, and disposing the substrate W at a position at which it closes the upper end opening portion of the plating tank  602 . Inside the plating tank  602 , a flat plate-shaped anode plate (anode)  606  immersed in the plating liquid  600  to serve as an anodic electrode is horizontally placed, and the seed layer of the substrate W is to serve as cathodic electrode. The anode plate  606  comprises a copper plate or a gathering of copper balls. 
     A plating liquid supply pipe  610  having a pump  608  mounted inside is connected to the center of the bottom of the plating tank  602 . Outside of the plating tank  602 , a plating liquid receptacle  612  is placed. Further, the plating liquid which has flowed into the plating liquid receptacle  612  is returned to the pump  608  through a plating liquid return pipe  614 . 
     Because of this structure, the substrate W is held facedown at the top of the plating tank  602  by the substrate holder  604 , and rotated in this condition. With a predetermined voltage being applied between the anode plate  606  (anodic electrode) and the seed layer of the substrate W (cathodic electrode), the pump  608  is driven to introduce the plating liquid  600  into the plating tank  602 , whereby a plating electric current is flowed between the anode plate  606  and the seed layer of the substrate W to form a plated copper film on the lower surface of the substrate W. At this time, the plating liquid  600  which has overflowed the plating tank  602  is recovered by the plating liquid receptacle  612 , and circulated. 
     Copper easily diffuses into a silicon dioxide film during a semiconductor manufacturing process to deteriorate the insulating properties of the silicon dioxide film, and causes cross contamination during the steps of transportation, storage and processing of the substrate. Copper may also contaminate the interior of the clean room. 
     In detail, the substrate having the copper seed layer formed thereon used to be transported, while being placed in the substrate cassette, to the copper plating device, and the substrate having the copper film formed in the copper plating device used to be transported, while being put in the substrate cassette, to the CMP device. Thus, copper particles and copper ions adhering to the substrate, which are very active and harmful to other processes, were likely to diffuse into the clean room. 
     When a plated copper film is deposited on the surface of the substrate by use of a copper electroplating device, a voltage between the center of the seed layer of the substrate and the anode differs from a voltage between the periphery of the seed layer of the substrate and the anode, because of the electrical resistance of the copper seed layer formed on the surface of the substrate. Thus, the film thickness of the plated copper film on the periphery of the substrate is greater than the film thickness of the plated copper film at the center of the substrate. 
     When the plated copper film thicker on the periphery than at the center of the substrate is polished by a polishing device, the plated copper film remains unpolished on the periphery of the substrate, or the plated copper film at the center is scraped excessively, which is a phenomenon called dishing. 
     The distance between the anode and the substrate may be fully lengthened to increase the electric resistance of the plating liquid itself, thereby diminishing the influence of the electric resistance of the copper seed layer. This measure can make the film thickness of the plated copper film more uniform, but leads to upsizing of the apparatus. 
     DISCLOSURE OF INVENTION 
     The present invention has been accomplished in light of the foregoing circumstances. Its object is to provide a substrate processing method which can deposit the plated copper film on the surface of the substrate more uniformly; which can polish away a surplus plated copper film without leaving unscraped portions or causing dishing; and which can prevent the contamination of the interior of the clean room with hazardous copper coming from the copper film, such as the copper seed layer or copper film, formed on the surface of the substrate. 
     According to an aspect of the present invention, there is provided a method of filling a metal in fine trenches in a surface of a substrate, comprising: forming a barrier layer on the substrate, and a seed layer on the barrier layer; providing an electroplating apparatus having a first substrate holder for holding the substrate, a plating bath containing a plating liquid, an anode, and a virtual anode to adjust electromagnetic field; providing a polishing apparatus having a second substrate holder for holding the substrate to press the substrate against a polishing surface at different pressures at a central portion and a peripheral portion of the substrate; transferring the substrate with the barrier layer and the seed layer to the electroplating apparatus; holding the substrate in the first substrate holder and placing the substrate in the plating liquid; generating electromagnetic field; filling a first metal in the trenches and forming a plated film of the first metal on an entire surface of the substrate by electroplating, wherein the electromagnetic field is adjusted by the virtual anode so that differences of thickness of the plated film between the central portion and the peripheral portion of the substrate being minimized; removing the substrate from the plating bath; washing and drying the substrate in the electroplating apparatus; transferring the substrate to the polishing apparatus; holding the substrate in the second substrate holder; polishing and removing the plated film by pressing the substrate to the polishing surface, wherein the pressures pressing the substrate to the polishing surface at a central portion and a peripheral portion are adjusted; washing and drying the substrate in the polishing apparatus; and transferring the substrate from the polishing apparatus. 
     According to another aspect of the present invention there is provided a method of filling a metal in trenches in a surface of a substrate, comprising; providing an electroplating apparatus; providing a polishing apparatus having a substrate holder for holding the substrate to press the substrate against a polishing surface at different pressures at a central portion and a peripheral portion of the substrate; forming a barrier layer on the substrate; transferring the substrate with the barrier layer to the electroplating apparatus; holding the substrate in a first plating liquid in the electroplating apparatus; electroplating a first layer on the entire surface of the barrier layer using the first plating liquid; holding the substrate in a second plating liquid in the electroplating apparatus; filling a metal in the trenches covered by the first layer and forming a second plating layer of the metal on the surface of the substrate using the second plating liquid; washing and drying the substrate in the electroplating apparatus; transferring the substrate to the polishing apparatus; holding the substrate in the substrate holder; polishing the second plating layer by pressing the substrate to the polishing surface, wherein the pressures pressing the substrate to the polishing surface at a central portion and a peripheral portion are adjusted; washing and drying the substrate in the polishing apparatus; and transferring the substrate from the polishing apparatus. 
     According to still another aspect of the present invention there is provided a method of filling a metal in trenches in a surface of a substrate, comprising: forming a barrier layer on the substrate, and a seed layer on the barrier layer; providing an electroplating apparatus having a first substrate holder for holding the substrate, a plating bath containing a plating liquid, and an anode; providing a polishing apparatus having a second substrate holder for holding the substrate to press the substrate against a polishing surface; transferring the substrate with the barrier layer and the seed layer to the electroplating apparatus; reinforcing the seed layer by depositing an additional metal in electroplating unit or electroless-plating unit; holding the substrate in the first substrate holder and placing the substrate in the plating liquid; generating electromagnetic field; filling a first metal in the trenches and forming a plated film of the first metal on an entire surface of the substrate by electroplating; removing the substrate from the plating bath; washing and drying the substrate in the electroplating apparatus; transferring the substrate to the polishing apparatus; holding the substrate in the second substrate holder; polishing and removing the plated film by pressing the substrate to the polishing surface; cap-plating a second metal to form a protective plated layer on the plated film of the polished substrate after polishing; and washing and drying the substrate. 
     According to still another aspect of the present invention there is provided a method of filling a metal in trenches in a surface of a substrate, comprising; providing a plating apparatus; providing a polishing apparatus having a substrate holder for holding the substrate to press the substrate against a polishing surface at different pressures at a central portion and a peripheral portion of the substrate; forming a barrier layer on the substrate; transferring the substrate with the barrier layer to the plating apparatus; holding the substrate in a first plating liquid in the plating apparatus; electroless-plating a first layer on the entire surface of the barrier layer using the first plating liquid in the electroplating apparatus; holding the substrate in a second plating liquid in the plating apparatus; generating electromagnetic field between the substrate and an anode; filling a metal in the trenches covered by the first layer and forming a second plating layer of the metal on the surface of the substrate using the second plating liquid; washing and drying the substrate in the plating apparatus; transferring the substrate to the polishing apparatus; holding the substrate in the substrate holder; polishing the second plating layer by pressing the substrate to the polishing surface, wherein the pressures pressing the substrate to the polishing surface at a central portion and a peripheral portion are adjusted; washing and drying the substrate in the polishing apparatus; and transferring the substrate from the polishing apparatus. 
     The above and other objects, features, and advantages of the present invention will be apparent from the following description when taken in conjunction with the accompanying drawings which illustrates preferred embodiments of the present invention by way of example. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view showing the entire constitution of a substrate processing apparatus according to an embodiment of the present invention; 
         FIG. 2  is an entire layout drawing of a plating device; 
         FIG. 3  is a view showing a loading/unloading portion of the plating device; 
         FIG. 4  is a schematic sectional view of a plating unit of the plating device; 
         FIG. 5  is a schematic view of a substrate cleaning device of the plating device; 
         FIG. 6  is a schematic sectional view showing another example of the substrate cleaning device of the plating device; 
         FIG. 7  is an entire layout drawing of a CMP device; 
         FIG. 8  is a view showing the relationship between a top ring and a polishing table of the CMP device; 
         FIG. 9  is a cross-sectional view showing a relationship between a top ring and a polishing table of the CMP device; 
         FIG. 10  is a vertical cross-sectional view showing the top ring shown in  FIG. 9 ; 
         FIG. 11  is a bottom view of the top ring shown in  FIG. 9 ; 
         FIGS. 12A through 12E  are vertical cross-sectional views showing other examples of contact members (central bag and ring tube) in a top ring of the CMP device; 
         FIG. 13  is a vertical cross-sectional view showing another example of contact members (central bag and ring tube) in a top ring of the CMP device; 
         FIGS. 14A and 14B  are vertical cross-sectional views showing other examples of contact members (central bag and ring tube) in a top ring of the CMP device; 
         FIG. 15  is a vertical cross-sectional view showing another top ring of the CMP device; 
         FIG. 16  is a vertical cross-sectional view showing still another example of contact members (central bag and ring tube) in a top ring of the CMP device; 
         FIG. 17  is a plan view showing a substrate transport box; 
         FIG. 18  is a front view showing the substrate transport box; 
         FIG. 19  is a sectional plan view showing a different example of the substrate transport box; 
         FIG. 20  is a sectional view taken on line A—A of  FIG. 19 ; 
         FIG. 21  is a front view of the different substrate transport box; 
         FIG. 22  is a bottom view of the different substrate transport box; 
         FIG. 23  is a view attached to a description of the state of use of the different substrate transport box; 
         FIG. 24  is a sectional plan view showing a further different example of the substrate transport box; 
         FIG. 25  is a sectional view taken on line B—B of  FIG. 24 ; 
         FIG. 26  is a view showing another example of the entire constitution of the substrate processing apparatus; 
         FIG. 27  is a view showing still another example of the entire constitution of the substrate processing apparatus; 
         FIG. 28  is a schematic sectional view showing an example of a copper plating device having a film thickness distribution adjusting function; 
         FIG. 29  is a schematic sectional view showing another example of the copper plating device having the film thickness distribution adjusting function; 
         FIG. 30  is a schematic sectional view showing another example of the copper plating device having the film thickness distribution adjusting function; 
         FIG. 31  is a schematic sectional view showing another example of the copper plating device having the film thickness distribution adjusting function; 
         FIG. 32  is a schematic sectional view showing another example of the copper plating device having the film thickness distribution adjusting function; 
         FIG. 33  is a schematic sectional view showing another example of the copper plating device having the film thickness distribution adjusting function; 
         FIG. 34  is a schematic sectional view showing another example of the copper plating device having the film thickness distribution adjusting function; 
         FIG. 35  is a schematic sectional view showing another example of the copper plating device having the film thickness distribution adjusting function; 
         FIG. 36  is a schematic sectional view showing another example of the copper plating device having the film thickness distribution adjusting function; 
         FIG. 37  is a schematic sectional view showing another example of the copper plating device having the film thickness distribution adjusting function; 
         FIG. 38  is a schematic sectional view showing another example of the copper plating device having the film thickness distribution adjusting function; 
         FIG. 39  is a schematic sectional view showing another example of the copper plating device having the film thickness distribution adjusting function; 
         FIG. 40  is a schematic sectional view showing another example of the copper plating device having the film thickness distribution adjusting function; 
         FIG. 41  is a perspective view showing an example of a CMP device having a polishing amount adjusting function; 
         FIG. 42  is a longitudinally sectional front view of  FIG. 41 ; 
         FIGS. 43A and 43B  are views showing a modification of  FIG. 42 ,  FIG. 43A  being a plan view, and  FIG. 43B  being a longitudinally sectional front view; 
         FIG. 44  is a perspective view showing another example of the CMP device having the polishing amount adjusting function; 
         FIG. 45  is a longitudinally sectional front view of  FIG. 44 ; 
         FIG. 46  is a plan view of  FIG. 45 ; 
         FIG. 47  is a layout plan view showing another example of the substrate processing apparatus; 
         FIG. 48  is a layout plan view showing still another example of the substrate processing apparatus; 
         FIGS. 49A through 49E  are views attached to a description of two-stage plating; 
         FIG. 50  is a view attached to a description of a modification of  FIGS. 49A through 49E ; 
         FIG. 51  is a block diagram showing an example of measuring the electric resistance of a copper seed layer to control the copper plating device and the CMP device; 
         FIG. 52  is a sectional view showing an example of an electric terminal member serving concurrently as a copper seed layer resistance measuring terminal and a cathode; 
         FIG. 53  is a perspective view showing a part of  FIG. 52 ; 
         FIGS. 54A through 54C  are sectional views showing different examples of the electric terminal; 
         FIGS. 55A and 55B  are sectional views attached to a description of a centering mechanism with different electric terminal members; 
         FIG. 56  is a view attached to a description of measurement of the electric resistance of the copper seed layer with the use of the electric terminal member shown in  FIG. 52 ; 
         FIG. 57  is a view attached to a description of another method for measuring the electric resistance of the copper seed layer; 
         FIGS. 58A and 58B  are views attached to a description of still another method for measuring the electric resistance of the copper seed layer; 
         FIGS. 59A through 59C  are views attached to a description of a further method for measuring the electric resistance of the copper seed layer; 
         FIG. 60  is a sectional view showing another example of the electric terminal member serving concurrently as a copper seed layer resistance measuring terminal and a cathode; 
         FIG. 61  is a view attached to a description of measurement of the electric resistance of the copper seed layer with the use of the electric terminal member shown in  FIG. 60 ; 
         FIGS. 62A through 62C  are views showing an example of forming a copper interconnection by copper plating in the sequence of steps; 
         FIG. 63  is a view showing the entire constitution of a conventional substrate processing apparatus; 
         FIG. 64  is a schematic sectional view showing a conventional plating device; 
         FIG. 65  is a plan view of an example of a substrate plating apparatus; 
         FIG. 66  is a schematic view showing airflow in the substrate plating apparatus shown in  FIG. 65 ; 
         FIG. 67  is a cross-sectional view showing airflows among areas in the substrate plating apparatus shown in  FIG. 65 ; 
         FIG. 68  is a perspective view of the substrate plating apparatus shown in  FIG. 65 , which is placed in a clean room; 
         FIG. 69  is a plan view of another example of a substrate plating apparatus; 
         FIG. 70  is a plan view of still another example of a substrate plating apparatus; 
         FIG. 71  is a plan view of still another example of a substrate plating apparatus; 
         FIG. 72  is a view showing a plan constitution example of the semiconductor substrate processing apparatus; 
         FIG. 73  is a view showing another plan constitution example of the semiconductor substrate processing apparatus; 
         FIG. 74  is a view showing still another plan constitution example of the semiconductor substrate processing apparatus; 
         FIG. 75  is a view showing still another plan constitution example of the semiconductor substrate processing apparatus; 
         FIG. 76  is a view showing still another plan constitution example of the semiconductor substrate processing apparatus; 
         FIG. 77  is a view showing still another plan constitution example of the semiconductor substrate processing apparatus; 
         FIG. 78  is a view showing a flow of the respective steps in the semiconductor substrate processing apparatus illustrated in  FIG. 77 ; 
         FIG. 79  is a view showing a schematic constitution example of a bevel and backside cleaning unit; 
         FIG. 80  is a view showing a schematic constitution of an example of an electroless-plating apparatus; 
         FIG. 81  is a view showing a schematic constitution of another example of an electroless-plating apparatus; 
         FIG. 82  is a vertical sectional view of an example of an annealing unit; 
         FIG. 83  is a transverse sectional view of the annealing unit; 
         FIG. 84  is a plan view showing another plating unit; 
         FIG. 85  is a sectional view taken on line A—A of  FIG. 84 ; 
         FIG. 86  is an enlarged sectional view of a substrate holder and a cathode portion; 
         FIG. 87  is a front view of a substrate holder; 
         FIG. 88  is a sectional view of a cathode portion; 
         FIG. 89  is a plan view of an electrode arm; 
         FIG. 90  is a longitudinal sectional front view of  FIG. 89 ; 
         FIG. 91  is a sectional view taken on line E—E of  FIG. 89 ; 
         FIG. 92  is an enlarged view showing a part of  FIG. 91  in an enlarged manner; 
         FIG. 93  is a plan view of a state in which a housing of an electro portion of the electrode arm has been removed; 
         FIG. 94  is a flow diagram showing the flow of reinforcing process steps of a seed layer; and 
         FIGS. 95A through 95C  illustrate, in a sequence of process steps, for forming interconnects made of copper by plating a surface of a substrate, thereafter forming a protective layer on the interconnects selectively. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which in no way limit the invention. 
       FIG. 1  shows the entire constitution of a substrate processing apparatus according to an embodiment of the present invention. In a clean room, an insulating film forming device  10 , a lithography and etching device  12 , a barrier layer forming device  14 , a copper seed layer forming device  16 , a copper plating device  18 , and a CMP device  20  are housed. On the surface of a substrate W, an insulating film  2  is formed by the insulating film forming device  10 , a contact hole  3  and a trench  4  for an interconnection are formed by the lithography and etching device  12 , a barrier layer  5  is formed by the barrier layer forming device  14 , and a copper seed layer  7  is formed by the copper seed layer forming device  16 , in this sequence, as shown in  FIG. 62A . Copper plating is applied to the surface of the substrate W by the copper plating device  18  to form a copper film  6 , as shown in  FIG. 62B . Then, chemical mechanical polishing is carried out on the surface of the substrate W by the CMP device  20  to form an interconnection composed of the copper film  6  shown in  FIG. 62C . 
     The copper seed layer forming device  16  for forming the copper seed layer  7  on the surface of the substrate W, the copper plating device  18  for forming the copper film  6  by applying copper plating to the surface of the substrate W, and the CMP device  20  for treating the substrate W exposed the copper film  6  are separated by partition walls in the clean room, and are also isolated from the clean room. The substrates W with the copper seed layer  7  or the copper film  6  exposed on the surface thereof are housed in a substrate cassette  22 . The substrate cassette  22  is placed in a substrate transport box  24 , and the substrates W are transported, in a hermetically sealed condition, to a next step by the substrate transport box  24  together with the substrate cassette  22 . That is, transport of the substrates W from the copper seed layer forming device  16  to the copper plating device  18 , transport of the substrates W from the copper plating device  18  to the CMP device  20 , and transport of the substrates W from the CMP device  20  are performed, with the substrates W being housed in the substrate cassette  22 , and with the substrate cassette  22  being sealed up in the substrate transport box  24 . Namely, these transport activities are performed, with the substrates W being isolated from the clean room. 
       FIG. 2  shows the entire configuration of the copper plating device  18 . This plating device  18  is housed in a rectangular facility  26  separated by partition walls, and is adapted to perform copper plating of a semiconductor substrate continuously. This facility  26  is partitioned by a partition wall  28  into a plating space  30  and a clean space  32 , and the plating space  30  and the clean space  32  are each capable of air intake and exhaust independently. The partition wall  28  is provided with an openable/closable shutter (not shown). The pressure of the clean space  32  is lower than the atmospheric pressure, and higher than the pressure of the plating space  30 . Thus, air inside the clean space  32  does not flow out into the clean room outside the facility  26 , and air inside the plating space  30  does not flow into the clean space  32 . 
     A loading/unloading portion  35  for placing the substrate transport box  24  housing the substrate cassettes  22 , and two cleaning/drying devices  27  for cleaning (rinsing) a plated substrate with pure water and drying the cleaned substrate are disposed inside the clean space  32 . A fixed and rotatable first transport device (four-axis robot)  29  for transporting the substrate is further provided. The cleaning/drying device  27  used is, for example, of the type which has cleaning liquid supply nozzles for supplying ultrapure water to both of the face side and the back side of the substrate, and spins the substrate at a high speed to dewater and dry it. 
     Inside the plating space  30 , there are disposed two pretreatment units  33  for pretreating the substrate before plating, and turning the substrate upside down by an inverting machine  31 ; four plating units  34  for applying copper plating to the surface of the substrate facedown; and two first substrate stages  36   a  and  36   b  for placing and holding the substrate. A self-propelled, rotatable second transport device (four-axis robot)  38  for transporting the substrate is also provided. 
     In the clean space  32 , there are disposed two substrate cleaning devices  40  for cleaning the plated substrate with a chemical solution, such as an acid solution or an oxidizing agent solution; and two second substrate stages  42   a  and  42   b  located between the substrate cleaning devices  40  and the cleaning/drying devices  27 . A fixed, rotatable third transport device (four-axis robot)  44  for transporting the substrate is provided at a position interposed between the two substrate cleaning devices  40 . 
     One of the first substrate stages  36   b , and one of the second substrate stages  42   b , are adapted to allow the substrate to be washed with water, and are each provided with an inverting machine  31  for turning the substrate upside down. 
     The first transport device  29  is adapted to transport the substrate among the substrate cassette  22  placed and housed in the loading/unloading portion  35 , the cleaning/drying devices  27 , and the second substrate stages  42   a ,  42   b . The second transport device  38  is adapted to transport the substrate among the first substrate stages  36   a ,  36   b , the pretreatment units  33 , and the plating units  34 . The third transport device  44  is adapted to transport the substrate among the first substrate stages  36   a ,  36   b , the substrate cleaning devices  40 , and the second substrate stages  42   a ,  42   b.    
     Inside the facility  26 , a container  46  for accommodating an adjusting-operation substrate is incorporated below the first substrate stage  36   a . The second transport device  38  is adapted to withdraw the adjusting-operation substrate from the container  46 , and return this substrate to the container  46  after an adjusting operation ends. In this manner, the container  46  for accommodating the adjusting-operation substrate is disposed inside the facility  26 , thus making it possible to prevent contamination or a decrease in throughput associated with the introduction of the adjusting-operation substrate from the outside for an adjusting operation. 
     The position of disposition of the container  46  may be any position in the facility  26  as long as it is a position allowing the adjusting-operation substrate to be withdrawn and accommodated by any of the transport devices. By disposing the container  46  near the first substrate stage  36   a , an adjusting operation using the adjusting-operation substrate can be started for pretreatment, followed by plating, and the substrate after cleaning/drying can be returned into the container  46 . 
     The pretreatment units for applying pretreatment for increasing wettability of the substrate with a plating can be omitted. Alternatively, a preplating unit for performing preplating for the purpose of reinforcing the copper seed layer formed on the substrate before execution of plating can be installed in place of one of the plating units or one of the pretreatment units. In this case, a water-washing unit for performing water washing between preplating and plating and/or after plating is installed instead of the pretreatment unit. 
     The transport device  29  used is one having two drop-in hands, one of which located upper side is a dry hand, the other located lower side being a wet hand. The transport devices  38 ,  44  used are each one having two drop-in hands, both of which are wet hands. Needless to say, however, such transport devices are not restrictive. 
     Next, the flow of the substrate in the plating device  18  will be outlined. The substrate is housed in the substrate cassette  22  with its surface (semiconductor device formation side, or processing side) directed upward, and the substrate cassette  22  is housed in the substrate transport box  24 . In this state, the substrates are transported to and placed in the loading/unloading portion  35 . The first transport device  29  withdraws the substrate from the substrate cassette  22 , moves it toward the second substrate stage  42   a , and places it on the second substrate stage  42   a . The third transport device  44  transfers the substrate present on the second substrate stage  42   a  to the first substrate stage  36   a . Then, the second transport device  38  receives the substrate from the first substrate stage  36   a , and passes it on to the pretreatment unit  33 . After completion of pretreatment by the pretreatment unit  33 , the inverting machine  31  turns the substrate upside down so that the surface of the substrate faces downward. The inverted substrate is handed to the second transport device  38  again. The second transport device  38  passes the substrate on to a plating head of the plating unit  34 . 
     After the substrate is plated and dehydrated of the plating liquid in the plating unit  34 , the substrate is passed on to the second transport device  38 , which carries the substrate to the first substrate stage  36   b . The substrate is inverted by the inverting machine  31  of the first substrate stage  36   b  so that its face side faces upward. In the inverted state, the substrate is moved to the substrate cleaning device  40  by the third transport device  44 . The substrate, which has been cleaned with the chemical solution, rinsed with pure water, and spin-extracted in the substrate cleaning device  40 , is carried to the first substrate stage  42   b  by the third transport device  44 . Then, the first transport device  29  receives the substrate from the first substrate stage  42   b , and transfers the substrate to the cleaning/drying device  27 , which rinses the substrate with pure water and spin-dries it. The spin-dried substrate is transported by the first transport device  29 , and returned to the substrate cassette  22  within the substrate transport box  24  transported to the loading/unloading portion  35 . 
     Here, pretreatment by the pretreatment unit can be omitted. When the preplating unit is installed, the substrate withdrawn from the substrate cassette is subjected to preplating by the preplating unit, and after a water-washing step or without a water-washing step, the substrate is plated by the plating unit. After plating, the substrate is put to, or not put to, a water-washing step, and transported to the first cleaning device. 
       FIG. 3  is a view showing the loading/unloading portion  35 . The loading/unloading portion  35  is provided with stages  50  placing the substrate transport boxes  24  housing substrate cassettes  22 . When the substrate transport box  24  is placed on an elevating stand  52  of the stage  50 , the elevating stand  52  and a bottom plate  24   a  of the substrate transport box  24  are locked together. The bottom plate  24   a  is mounted on the bottom of the substrate transport box  24  so as to close an opening of the bottom of substrate transport box  24 . However, simultaneously with the locking of the elevating stand  52  and the bottom plate  24   a , the stage  50  and the substrate transport box  24  intimately contact each other, and the bottom plate  24   a  is liberated from the substrate transport box  24  for a free state. 
     The elevating stand  52  is coupled to an elevating mechanism  54 , and the bottom plate  24   a  placing the substrate cassette  22 , once released from the substrate transport box  24  to become free, is moved up and down integrally with the elevating stand  52 . When the elevating stand  52  and the bottom plate  24   a  are confirmed to have been locked, the elevating stand  52  descends, and the bottom plate  24   a  placing the substrate cassette  22  moves downward, thereby making it possible to withdraw the substrate W from the substrate cassette  22 . 
       FIG. 4  shows the plating unit  34 , which mainly comprises a substantially cylindrical plating tank  62  holding a plating liquid  60 , and a plating head  64  disposed above the plating tank  62  and adapted to hold the substrate W.  FIG. 4  shows a state of the plating unit  34  being at a plating position at which the substrate W is held by the plating head  64  and the liquid level of the plating liquid  60  is raised. 
     The plating tank  62  has a plating chamber  68  open upward and having an anode  66  disposed at the bottom, and a plating vessel  70  containing the plating liquid  70  in the plating chamber  68 . On the inner circumferential wall of the plating vessel  70 , plating liquid ejection nozzles  72  horizontally protruding toward the center of the plating chamber  68  are arranged at equal intervals along the circumferential direction. These plating liquid ejection nozzles  72  communicate with a plating liquid supply passage extending vertically within the plating vessel  70 . 
     A punch plate  74  provided with many holes, for example, of about 3 mm is disposed at a position above the anode  66  in the plating chamber  68  so as to thereby prevent a black film, which is formed on the surface of the anode  66 , from being brought up by the plating liquid  60  and flowed out. 
     The plating vessel  70  is also provided with a first plating liquid discharge port  76  for pulling out the plating liquid  60  in the plating chamber  68  from the peripheral edge of the bottom of the plating chamber  68 , a second plating liquid discharge port  80  for discharging the plating liquid  60  which has overflowed a dam member  78  provided in an upper end portion of the plating vessel  70 , and a third plating liquid discharge port  82  for discharging the plating liquid before overflowing the dam member  78 . The plating liquids flowing through the second plating liquid discharge port  80  and the third plating liquid discharge port  82  are mixed at a lower end portion of the plating vessel  70  and discharged. 
     Because of this structure, when the amount of a plating supplied is large during plating, the plating liquid is discharged to the outside through the third plating liquid discharge port  82 , and simultaneously caused to overflow the dam member  78  and discharged to the outside through the second plating liquid discharge port  80 . When the amount of a plating supplied is small during plating, the plating liquid is discharged to the outside through the third plating liquid discharge port  82 , and simultaneously caused to pass through an opening (not shown) provided in the dam member  78 , and discharged to the outside through the second plating liquid discharge port  80 . These contrivances permit easy adaptation to the magnitude of the amount of a plating. 
     Near the periphery of the interior of the plating chamber  68 , a vertical stream regulating ring  84  and a horizontal stream regulating ring  86  are disposed by having the outer peripheral end of the horizontal stream regulating ring  86  secured to the plating vessel  70 . These stream regulating rings  84  and  86  serve to push up the center of the plating liquid surface by an upper flow of the plating liquid  60  divided into upper and lower flows in the plating chamber  68 , to smooth the lower flow, and make the distribution of an electric current density more uniform. 
     The plating head  64  has a rotatable, bottomed, cylindrical housing  90  open downward and having an opening  88  in a circumferential wall thereof, and vertically movable press rods  94  having a press ring  92  attached to the lower ends thereof. 
     The housing  90  is connected to an output shaft  98  of a motor  96 , and is adapted to rotate by driving of the motor  96 . The press rods  94  are suspended at predetermined positions along the circumferential direction of a ring-shaped support frame  108  rotatably supported via a bearing  106  at the lower end of a slider  104  movable upward and downward by the actuation of a guide-equipped cylinder  102  secured to a support  100  surrounding the motor  96 . Thus, the press rods  94  move up and down according to the actuation of the cylinder  102 , and when the substrate W is held, are adapted to rotate integrally with the housing  90 . 
     The support  100  is mounted on a slide base  114  screwed to, and moving upward and downward integrally with, a ball screw  112  rotating in accordance with the driving of a motor  110 . Further, the support  100  is surrounded with an upper housing  116 , and moved up and down together with the upper housing  116  in accordance with the driving of the motor  110 . A lower housing  118  surrounding the periphery of the housing  90  during plating is attached to the upper surface of the plating vessel  70 . 
       FIGS. 84 to 93  shows another example of a plating unit  2012 . The plating unit  2012 , as shown in  FIG. 84 , is provided with a substrate treatment section  2020  for performing plating treatment and treatment incidental thereto. A plating liquid tray  2022  for containing the plating liquid is disposed adjacent to the substrate treatment section  2020 . There is also provided an electrode arm portion  2030  having an electrode portion  2028  which is held at the free end of an arm  2026  swingable about a rotating shaft  2024  and which is swung between the substrate treatment section  2020 , and a plating liquid tray  2022 . Furthermore, a pre-coating/recovering arm  2032 , and fixed nozzles  2034  for ejecting pure water or a chemical liquid such as ion water, and further a gas or the like toward a substrate are disposed laterally of the substrate treatment section  2020 . In this embodiment, three of the fixed nozzles  2034  are disposed, and one of them is used for supplying pure water. 
     The substrate treatment section  2020 , as shown in  FIGS. 85 and 86 , has a substrate holder  2036  for holding a substrate W with its surface, to be plated, facing upward, and a cathode portion  2038  located above the substrate holder  2036  so as to surround a peripheral portion of the substrate holder  2036 . Further, a substantially cylindrical bottomed cup  2040  surrounding the periphery of the substrate holder  2036  for preventing scatter of various chemical liquids used during treatment is provided so as to be vertically movable by an air cylinder  2042 . 
     The substrate holder  2036  is adapted to be raised and lowered by air cylinders  2044  between a lower substrate transfer position A, an upper plating position B, and a pretreatment/cleaning position C intermediate between these positions. The substrate holder  2036  is also adapted to rotate at an arbitrary acceleration and an arbitrary velocity integrally with the cathode portion  2038  by a rotating motor  2046  and a belt  2048 . A substrate carry-in and carry-out opening (not shown) is provided in confrontation with the substrate transfer position A in a side surface of the plating unit  2012 . When the substrate holder  2036  is raised to the plating position B, a seal member  2090  and cathode electrodes  2088  (to be described below) of the cathode portion  2038  are brought into contact with the peripheral edge portion of the substrate W held by the substrate holder  2036 . On the other hand, the cup  2040  has an upper end located below the substrate carry-in and carry-out opening, and when the cup  2040  ascends, the upper end of the cup  2040  reaches a position above the cathode portion  2038  closing the substrate carry-in and carry-out opening, as shown by imaginary lines in  FIG. 86 . 
     The plating liquid tray  2022  serves to wet a plating liquid impregnated material  2110  and an anode  2098  (to be described later on) of the electrode arm portion  2030  with a plating liquid, when plating has not been performed. 
     As shown in  FIG. 87 , the substrate holder  2036  has a disk-shaped substrate stage  2068  and six vertical support arms  2070  disposed at spaced intervals on the outer circumferential edge of the substrate stage  2068  for holding a substrate W in a horizontal plane on respective upper surfaces of the support arms  2070 . Chucking fingers  2076  are rotatably mounted on upper ends of the support arms  2070  for pressing the substrate W downwardly and gripping the outer circumferential edge of the substrate W. 
     The chucking fingers  2076  have respective lower ends coupled to upper ends of pressing pins  2080  that are normally urged to move downwardly by coil springs  2078 . When the pressing pins  2080  are moved downwardly, the chucking fingers  2076  are rotated radially inwardly into a closed position. A support plate  2082  is disposed below the substrate stage  2068  for engaging lower ends of the opening pins  2080  and pushing them upwardly. 
     When the substrate holder  2036  is located in the substrate transfer position A shown in  FIG. 85 , the pressing pins  2080  are engaged and pushed upwardly by the support plate  2082 , so that the chucking fingers  2076  rotate outwardly and open. When the substrate stage  2068  is elevated, the opening pins  2080  are lowered under the resiliency of the coil springs  2078 , so that the chucking fingers  2076  rotate inwardly and close. 
     As shown in  FIG. 88 , the cathode portion  2038  comprises an annular frame  2086  fixed to upper ends of vertical support columns  2084  mounted on the peripheral edge of the support plate  2082  (see  FIG. 87 ), a plurality of cathode electrodes  2088  attached to a lower surface of the annular frame  2086  and projecting inwardly, and an annular sealing member  2090  mounted on an upper surface of the annular frame  2086  in covering relation to upper surfaces of the cathode electrodes  2088 . The sealing member  2090  is adapted to have an inner circumferential edge portion inclined inwardly downwardly and progressively thin-walled, and to have an inner circumferential end suspending downwardly. 
     When the substrate holder  2036  has ascended to the plating position B, as shown  FIG. 86 , the cathode electrodes  2088  are pressed against the peripheral edge portion of the substrate W held by the substrate holder  2036  for thereby allowing electric current to pass through the substrate W. At the same time, an inner circumferential end portion of the seal member  2090  is brought into contact with an upper surface of the peripheral edge of the substrate W under pressure to seal its contact portion in a watertight manner. As a result, the plating liquid supplied onto the upper surface (surface to be plated) of the substrate W is prevented from seeping from the end portion of the substrate W, and the plating liquid is prevented from contaminating the cathode electrodes  2088 . 
     As shown in  FIGS. 89 through 93 , the electrode head  2028  of the electrode arm portion  2030  comprises a housing  2094  coupled to a free end of the swing arm  2026  through a ball bearing  2092 , a cylindrical support frame  2096  surrounding the housing  2094 , and an anode  2098  fixed by having a peripheral edge portion gripped between the housing  2094  and the support frame  2096 . The anode  2098  covers an opening of the housing  2094 , which has a suction chamber  2100  defined therein. In the suction chamber  2100 , there is disposed a diametrically extending plating liquid introduction pipe  2104  connected to a plating liquid supply pipe  2102  which extends from the plating liquid supply unit (not shown), and held in abutment against an upper surface of the anode  2098 . A plating liquid discharge pipe  2106  communicating with the suction chamber  2100  is connected to the housing  2094 . 
     The plating liquid introduction pipe  2104  is effective to supply the plating liquid uniformly to the surface, to be plated, if the plating liquid introduction pipe  2104  is of a manifold structure. Specifically, the plating liquid introduction pipe  2104  has a plating liquid introduction passage  104   a  extending continuously in its longitudinal direction, and a plurality of plating liquid introduction ports  2104   b  spaced at a given pitch along the plating liquid introduction passage  2104   a  and extending downwardly therefrom in communication therewith. The anode  2098  has a plurality of plating liquid supply ports  2098   a  defined therein at positions corresponding to the plating liquid introduction ports  2104   b . The anode  2098  also has a number of vertically extending through holes  2098   b  defined therein over its entire region. The plating liquid that is introduced from the plating liquid supply pipe  2102  into the plating liquid introduction pipe  2104  flows through the plating liquid introduction ports  2104   b  and the plating liquid supply ports  2098   a  to a position below the anode  2098 . With the anode  2098  being immersed in the plating liquid, the plating liquid discharge pipe  2106  is evacuated to discharge the plating liquid below the anode  2098  via the through holes  2098   b  and the suction chamber  2100  from the plating liquid discharge pipe  2106 . 
     In this embodiment, a plating liquid impregnated material  2110  comprising a water-retaining material and covering the entire surface of the anode  2098  is attached to the lower surface of the anode  2098 . The plating liquid impregnated material  2110  is impregnated with the plating liquid to wet the surface of the anode  2098 , thereby preventing a black film from falling onto the plated surface of the substrate by drying, and oxidizing, and simultaneously facilitating escape of air to the outside when the plating liquid is poured between the surface, to be plated, of the substrate and the anode  2098 . 
     The plating liquid impregnated material  2110  has both functions of retaining liquid and passing liquid therethrough, and has excellent chemical resistance. Specially, the plating liquid impregnated material  2110  has endurance against an acid plating liquid including sulfuric acid having high concentration. The plating liquid impregnated material  2110  comprises, for example, a woven fabric of polypropylene to prevent elution of the impurity in the sulfuric acid solution from having a bad influence to the plating efficiency (plating speed, resistivity and filling characteristics). The plating liquid impregnated material  2110  may comprises at least one material of polyethylene, polyester, polyvinyl chloride, Teflon, polyvinyl alcohol, polyurethane, and derivatives of these materials, other than polypropylene. Nonwoven fabric or sponge-like structure may use in place of woven fabric. Porous ceramics and sintered polypropylene made of Alumina and SiC and the like are available. 
     Many fixing pins  2112  each having a head portion at the lower end are arranged such that the head portion is provided in the plating liquid impregnated material  2110  so as not to be releasable upward and a shaft portion pierces the interior of the anode  2098 , and the fixing pins  2112  are urged upward by U-shaped plate springs  2114 , whereby the plating liquid impregnated material  2110  is brought in close contact with the lower surface of the anode  2098  by the resilient force of the plate springs  2114  and is attached to the anode  2098 . With this arrangement, even when the thickness of the anode  2098  gradually decreases with the progress of plating, the plating liquid impregnated material  2110  can be reliably brought in close contact with the lower surface of the anode  2098 . Thus, it can be prevented that air enters between the lower surface of the anode  2098  and the plating liquid impregnated material  2110  to cause poor plating. 
     When the impregnated material  2110  has a sufficient strength such as a porous ceramics, the anode may be placed on the impregnated material without using pins for fixing the impregnated material. 
     When the substrate holder  2036  is in the plating position B (see  FIG. 86 ), the electrode head  2028  is lowered until the gap between the substrate W held by the substrate holder  2036  and the plating liquid impregnated material  2110  becomes about 0.5 to 3 mm, for example. Then, the plating liquid is supplied from the plating liquid supply pipe  2102  to fill the gap between the upper surface, to be plated, of the substrate W and the anode  2098  while impregnating the plating liquid impregnated material  2110  with the plating liquid, thus plating the upper surface of the substrate W. 
       FIG. 5  is a schematic view of the substrate cleaning device  40 . As shown in  FIG. 5 , the substrate W, such as a substrate, having a circuit formed in areas excluding a peripheral edge portion of its surface is gripped by spin chucks  120  at a plurality of locations along the circumferential direction of the peripheral edge portion, and horizontally held by a substrate holder  122 . Thus, the substrate W is adapted to rotate horizontally at a high speed. The substrate may be held vertically by a holding mechanism, but its horizontal holding will be described herein. A center nozzle  124  is disposed downwardly above a nearly central part of the surface of the substrate W held by the substrate holder  122 , and an edge nozzle  126  is disposed downwardly above the peripheral edge portion of the surface of the substrate. Furthermore, two back nozzles  128  and  130  are disposed upwardly beneath a nearly central part of the back side of the substrate W. The peripheral edge portion of the substrate refers to an area at the peripheral edge of the substrate where no circuit has been formed, or an area at the peripheral edge of the substrate where a circuit has been formed and which is finally not used as a chip. The center nozzle  124  can be installed at a desired position between the center and the peripheral edge portion of the surface of the substrate, but a feed solution from the nozzle is supplied to the center of the substrate. The center of the substrate refers to, preferably, within 20% of the diameter of the substrate, more preferably within 10% of the diameter of the substrate. Similarly, the back nozzles  128 ,  130  can be installed at desired positions between the center and the peripheral edge portion of the back side of the substrate, but the feed solution from the nozzles is preferably supplied to the center of the substrate. 
     As shown in  FIG. 6 , there may be one back nozzle  128  provided, and the edge nozzle  126  may be movable vertically or movable horizontally along the diametrical direction of the substrate W so that a height H from the substrate W or a range of movement width L, in the horizontal direction is adjustable. Moreover, the periphery of the substrate holder  122  may be surrounded with a waterproof cover  132 . Besides, a fixed nozzle (not shown) may be installed on an intra-device side surface of the waterproof cover  132  or the like, and pure water, deionized water or other chemical solution (an acid solution, an alkali solution, a surface active agent, or a corrosion inhibitor) may be supplied to the substrate according to the purpose. 
     Next, a cleaning method by this cleaning device will be described. 
     First, the substrate W is horizontally rotated integrally with the substrate holder  122 , with the substrate W being horizontally held by the substrate holder  122  via the spin chucks  120 . In this condition, an acid solution is supplied from the center nozzle  124  to the center of the surface of the substrate W. Even though a natural oxide film of copper has been formed at a circuit formation portion on the surface of the substrate W, this natural oxide film is immediately removed by the acid solution spreading over the entire surface of the substrate W as the substrate W rotates. Thus, the natural oxide film does not grow. For the acid solution, there may be used, for example, any one of, or a combination of, hydrochloric acid, hydrofluoric acid, sulfuric acid, citric acid, and oxalic acid which are generally used in a cleaning step of a semiconductor device manufacturing process. However, the acid solution may be a solution of any non-oxidizing acid. Hydrofluoric acid can be used for cleaning of the back side of the substrate W (to be described later on), and thus is preferred for sharing of the same chemical for different purposes. Also, hydrofluoric acid is preferably in a concentration of 0.1% by weight or more, in consideration of its effect of removing the oxide film. To avoid roughening of the copper surface, its concentration is preferably 5% by weight or less. 
     On the other hand, an oxidizing agent solution is supplied continuously or intermittently from the edge nozzle  126  to the peripheral edge portion of the substrate W. By this treatment, the copper film, etc. formed on the upper surface and end surface of the peripheral edge portion of the substrate W are rapidly oxidized with the oxidizing agent solution, and etched with the acid solution, which has been simultaneously supplied from the center nozzle  124  and has spread over the entire surface of the substrate W. As a result, the copper film, etc. are dissolved and removed. Etching with the acid solution-occurs also at sites other than the location of supply of the oxidizing agent solution, so that the concentration and the amount of supply of the acid solution need not be increased. For the oxidizing agent solution, there may be used, for example, any one of, or a combination of, ozone, hydrogen peroxide, nitric acid, and hypochlorite which are generally used in a cleaning step of a semiconductor device manufacturing process. If an ozone water is used, its amount is preferably 20 ppm or more, but 200 ppm or less. In the case of hydrogen peroxide, its preferred concentration is 10% by weight or more, but 80% by weight or less. If hypochlorite is used, its preferred concentration is 1% by weight or more, but 50% by weight or less. 
     At the same time, an oxidizing agent solution and an acid solution, such as hydrofluoric acid, are supplied simultaneously or alternately from the back nozzles  128  and  130  to the center of the back side of the substrate W. By this treatment, copper, etc. adhering to the back side of the substrate W can be oxidized with the oxidizing agent solution, along with the silicon of the substrate, and etched away with the acid solution. 
     In supplying the oxidizing agent solution and the acid solution from the two back nozzles  128  and  130  separately, simultaneously or alternately, if the supply of the oxidizing agent solution is stopped first, a hydrophobic surface is obtained; if the supply of the acid solution is stopped first, a hydrophilic surface is obtained. In either case, the back side of the substrate can be adjusted to one suitable for fulfilling the requirements of the subsequent process. 
     For the oxidizing agent solution, there can be cited, for example, any one of, or a combination of, ozone, hydrogen peroxide, nitric acid, and hypochlorite, as stated earlier. For the acid solution, there may be used the aforementioned non-oxidizing acid, such as hydrochloric acid, hydrofluoric acid, sulfuric acid, citric acid, or oxalic acid. In addition, copper can be removed with the use of an oxidizing acid, such as nitric acid, because there is no circuit on the back side of the substrate W unlike its face side. If an acid solution of an oxidizing acid such as nitric acid is used, this acid solution itself plays the role of an oxidizing agent solution, so that the oxidizing acid solution can be used alone, without using an oxidizing agent solution. Preferably, the oxidizing agent solution should be the same as the oxidizing agent solution supplied to the peripheral edge portion of the surface of the substrate W in order to decrease the types of the chemicals used. 
       FIG. 7  shows a whole structure of CMP device  20 . As shown in  FIG. 7 , the CMP device  20  comprises a loading/unloading portion  140  for placing substrate transport boxes  24  which house the substrate cassette  24 . The loading/unloading portion  140  includes four stages  50  shown in  FIG. 3 . A transfer robot  144  having two hands is provided on rails  142  so that the transfer robot  144  can move along the rails  142  and access the respective substrate cassettes  22  on the respective loading/unloading stages  50 . 
     The transfer robot  144  has two hands which are located in a vertically spaced relationship, and the lower hand is used only for taking out a substrate from the substrate cassette  22  and the upper hand is used only for returning the substrate to the substrate cassette  22 . This arrangement allows that a clean substrate which has been cleaned is placed at an upper side and is not contaminated. The lower hand is a vacuum attraction-type hand for holding a substrate under vacuum, and the upper hand is a recess support-type hand for supporting a peripheral edge of a substrate by a recess formed on the hand. The vacuum attraction-type hand can hold a substrate and transport the substrate even if the substrate is not located at a normal position in the substrate cassette  22  due to a slight displacement, and the recess support-type hand can transport a substrate while keeping the substrate clean because dust is not collected unlike the vacuum attraction-type hand. Two cleaning apparatuses  146  and  148  are disposed at the opposite side of the substrate cassettes  22  with respect to the rails  142  of the transfer robot  144 . The cleaning apparatuses  146  and  148  are disposed at positions that can be accessed by the hands of the transfer robot  144 . Between the two cleaning apparatuses  146  and  148  and at a position that can be accessed by the transfer robot  144 , there is provided a wafer station  158  having four wafer supports  150 ,  152 ,  154  and  156 . The cleaning apparatuses  146  and  148  have a spin-dry mechanism for drying a substrate by spinning the substrate at a high speed, and hence the two-stage cleaning or three-stage cleaning of the substrate can be conducted without replacing any cleaning module. 
     An area B in which the cleaning apparatuses  146  and  148  and the wafer station  158  having the wafer supports  150 ,  152 ,  154  and  156  are disposed and an area A in which the substrate cassettes  22  and the transfer robot  144  are disposed are partitioned by a partition wall  160  so that the cleanliness of the area B and the area A can be separated. The partition wall  160  has an opening for allowing substrates to pass therethrough, and a shutter  162  is provided at the opening of the partition wall  160 . A transfer robot  164  having two hands is disposed at a position where the transfer robot  164  can access the cleaning apparatus  146  and the three wafer supports  150 ,  154  and  156 , and a transfer robot  166  having two hands is disposed at a position where the transfer robot  166  can access the cleaning apparatus  148  and the three wafer supports  152 ,  154  and  156 . 
     The wafer support  150  is used to transfer a substrate between the transfer robot  144  and the transfer robot  164  and has a sensor  168  for detecting whether there is a substrate or not. The wafer support  152  is used to transfer a substrate between the transfer robot  144  and the transfer robot  166  and has a sensor  170  for detecting whether there is a substrate or not. The wafer support  154  is used to transfer a substrate from the transfer robot  166  to the transfer robot  164 , and has a sensor  172  for detecting whether there is a substrate or not and rinsing nozzles  178  for supplying a rinsing liquid to prevent a substrate from drying or to conduct rinsing of a substrate. The wafer support  156  is used to transfer a substrate from the transfer robot  164  to the transfer robot  166 , and has a sensor  176  for detecting whether there is a substrate or not and rinsing nozzles  178  for supplying a rinsing liquid to prevent a substrate from drying or to conduct rinsing of a substrate. The wafer supports  154  and  156  are disposed in a common water-scatter-prevention cover which has an opening defined therein for transferring substrates therethrough, the opening being combined with a shutter  188 . The wafer support  154  is disposed above the wafer support  156 , and the wafer support  154  serves to support a substrate which has been cleaned and the wafer support  156  serves to support a substrate to be cleaned, so that the cleaned substrate is prevented from being contaminated by rinsing water which would otherwise fall thereon. The sensors  168 ,  170 ,  172  and  174 , the rinsing nozzles  174  and  178 , and the shutter  180  are schematically shown in  FIG. 7 , and their positions and shapes are not illustrated exactly. 
     The transfer robot  164  and the transfer robot  166  have the respective two hands which are located in a vertically spaced relationship. The respective upper hands of the transfer robot  164  and the transfer robot  166  are used for transporting a substrate which has been cleaned to the cleaning apparatuses or the wafer supports of the wafer station  158 , and the respective lower hands of the transfer robot  164  and the transfer robot  166  are used for transporting a substrate which has not cleaned or a substrate to be polished. Since the lower hand is used to transfer a substrate to or from a reversing device, the upper hand is not contaminated by drops of a rinsing water which fall from an upper wall of the reversing device. 
     A cleaning apparatus  182  is disposed at a position adjacent to the cleaning apparatus  146  and accessible by the hands of the transfer robot  164 , and another cleaning apparatus  184  is disposed at a position adjacent to the cleaning apparatus  148  and accessible by the hands of the transfer robot  166 . 
     All the cleaning apparatuses  146 ,  148 ,  182  and  184 , the wafer supports  150 ,  152 ,  154  and  156  of the wafer station  158 , and the transfer robots  164  and  166  are placed in the area B. The pressure in the area B is adjusted so as to be lower than the pressure in the area A. Each of the cleaning apparatuses  182  and  184  is capable of cleaning both surfaces of a substrate. 
     The CMP device  20  has a housing  190  composed of partition walls for enclosing various components therein. The housing  190  constitutes an enclosing structure. The interior of the housing  190  is partitioned into a plurality of compartments or chambers (including the areas A and B) by partitions  160 ,  192 ,  194 ,  196  and  198 . 
     A polishing chamber separated from the area B by the partition wall  198  is formed, and is further divided into two areas C and D by the partition wall  198 . In each of the two areas C and D, there are provided two turntables, and a top ring for holding a substrate and pressing the substrate against the turntables during polishing. That is, the turntables  200  and  202  are provided in the area C, and the turntables  204  and  206  are provided in the area D. Further, the top ring  208  is provided in the area C and the top ring  210  is provided in the area D. 
     An abrasive liquid nozzle  212  for supplying an abrasive liquid to the turntable  200  in the area C and a dresser  214  for dressing the turntable  200  are disposed in the area C. An abrasive liquid nozzle  216  for supplying an abrasive liquid to the turntable  204  in the area D and a dresser  218  for dressing the turntable  204  are disposed in the area D. A dresser  220  for dressing the turntable  202  in the area C is disposed in the area C, and a dresser  222  for dressing the turntable  206  in the area D is disposed in the area D. The turntables  202  and  206  may be replaced with wet-type thickness measuring devices for measuring the thickness of a layer on a substrate. If such wet-type thickness measuring devices are provided, then they can measure the thickness of a layer on a substrate immediately after it is polished, and hence it is possible to further polish the polished substrate or control a polishing process for polishing a next substrate based on the measured value. 
       FIG. 8  shows the relationship between the top ring  208  and the turntables  200  and  202 . The relationship between the top ring  210  and the turntables  204  and  206  is the same as that of the top ring  208  and the turntables  200  and  202 . As shown in  FIG. 8 , the top ring  208  is supported from a top ring head  232  by a top ring drive shaft  230  which is rotatable. The top ring head  232  is supported by a support shaft  235  which can be angularly positioned, and the top ring  210  can access the turntables  200  and  202 . The dresser  214  is supported from a dresser head  236  by a dresser drive shaft  234  which is rotatable. The dresser head  236  is supported by an angularly positionable support shaft  238  for moving the dresser  214  between a standby position and a dressing position over the turntable  204 . The dresser  220  is similarly supported from a dresser head  242  by a dresser drive shaft  240  which is rotatable. The dresser head  242  is supported by an angularly positionable support shaft  244  for moving the dresser  220  between a standby position and a dressing position over the turntable  202 . 
     As shown in  FIG. 7 , in the area C separated from the area B by the partition wall  196  and at a position that can be accessed by the hands of the transfer robot  164 , there is provided a reversing device  250  for reversing a substrate, and at a position that can be accessed by the hands of the transfer robot  166 , there is provided a reversing device  252  for reversing a substrate. The partition wall  196  between the area B and the areas C, D has two openings each for allowing substrates to pass therethrough, one of which is used for transferring the substrate to or from the reversing device  250  and the other of which is used for transferring the substrate to or from the reversing device  252 . Shutters  254  and  256  are provided at the respective openings of the partition wall  196 . 
     The reversing devices  250  and  252  have a chuck mechanism for chucking a substrate, a reversing mechanism for reversing a substrate, and a substrate detecting sensor for detecting whether the chuck mechanism chucks a substrate or not, respectively. The transfer robot  164  transfers a substrate to the reversing device  250 , and the transfer robot  164  transfers a substrate to the reversing device  252 . 
     A rotary transporter  258  is disposed below the reversing devices  250  and  252 , and the top rings  208  and  210 , for transferring substrates between the cleaning chamber (area B) and the polishing chamber (areas C and D). The rotary transporter  258  has four stages for placing a substrate at equal angular intervals, and can hold a plurality of substrates thereon at the same time. The substrate which has been transported to the reversing device  250  or  252  is transferred to the rotary transporter  258  by actuating a lifter  260  or  262  disposed below the rotary transporter  258  when the center of the stage of the rotary transporter  258  is aligned with the center of the substrate held by the reversing device  250  or  252 . The substrate placed on the stage of the rotary transporter  258  is transported to a position below the top ring  208  or  210  by rotating the rotary transporter  258  by an angle of 90°. At this time, the top ring  208  or  210  is positioned above the rotary transporter  258  beforehand by a swing motion thereof. The substrate is transferred from the rotary transporter  258  to the top ring  208  or  210  by actuating a pusher  264  or  266  disposed below the rotary transporter  258  when the center of the top ring  208  or  210  is aligned with the center of the substrate placed on the stage of the rotary transporter  258 . 
     The substrate transferred to the top ring  208  or  210  is held under vacuum by a vacuum attraction mechanism of the top ring  208  or  210 , and transported to the turntable  200  or  204 . Thereafter, the substrate is polished by a polishing surface comprising a polishing cloth or a grinding stone (or a fixed abrasive plate) attached on the turntable  200  or  204 . The second turntables  202  and  206  are disposed at positions that can be accessed by the top rings  208  and  210 , respectively. With this arrangement, a primary polishing of the substrate can be conducted by the first turntable  200  or  204 , and then a secondary polishing of the substrate can be conducted by the second turntable  202  or  206 . Alternatively, the primary polishing of the substrate can be conducted by the second turntable  202  or  206 , and then the secondary polishing of the substrate can be conducted by the first turntable  200  or  204 . In this case, since the second turntable  202  or  206  has a smaller-diameter polishing surface than the first turntable  200  or  204 , a grinding stone (or a fixed abrasive plate) which is more expensive than a polishing cloth is attached to the second turntable  202  or  206  to thereby conduct a primary polishing of the substrate. On the other hand, the polishing cloth having a shorter life but being cheaper than the grinding stone (or the fixed abrasive plate) is attached to the first turntable  200  or  204  to thereby conduct a finish polishing of the substrate. This arrangement or utilization may reduce the running cost of the polishing apparatus. If the polishing cloth is attached to the first turntable and the grinding stone (or fixed abrasive plate) is attached to the second turntable, then the turntable system may be provided at a lower cost. This is because the grinding stone (or the fixed abrasive plate) is more expensive than the polishing cloth, and the price of the grinding stone (or the fixed abrasive plate) is substantially proportional to the diameter of the grinding stone. Further, since the polishing cloth has a shorter life than the grinding stone (or the fixed abrasive plate), if the polishing cloth is used under a relatively light load such as a finish polishing, then the life of the polishing cloth is prolonged. Further, if the diameter of the polishing cloth is large, the chance or frequency of the contact with the substrate is distributed to thus provide a longer life, a longer maintenance period, and an improved productivity of the semiconductor devices. 
     After a substrate is polished by the first turntable  200  and before the top ring  208  moves to the second turntable  202 , a cleaning liquid is supplied from cleaning liquid nozzles  270  disposed adjacent to the turntable  200  to the substrate held by the top ring  208  at a position where the top rind  208  is spaced from the turntable  200 . Because the substrate is rinsed before moving to the second turntable  202 , the transfer of contamination between the turntables is prevented to thus avoid cross contamination of the turntables. 
     Further, two-stage polishing can be performed in such a manner that a polishing cloth sold under the tradename of IC1000/SUBA400 manufactured by Rodel Nitta corporation is used for the first polishing surface and a polishing cloth sold under the tradename of POLITEX manufactured by Rodel Nitta corporation is used for the second polishing surface, and the substrate is first polished by the first polishing surface, and then polished by the second polishing surface. This two-stage polishing may be carried out by the use of the two large-sized turntables even if the small-sized second turntable is not used. In the above, although the two-stage polishing has been described as being conducted by two different polishing cloths, it may be conducted by the same polishing cloth or the same grinding stone. After the substrate is polished by the first polishing surface and the second polishing surface, the first and second polishing surfaces are dressed by the dressers  214 ,  218 ,  220  and  222 , respectively. The dressing process is a process for recovering the polishing surface of the turntable which has been degraded by polishing of the substrates. This process is also called conditioning or rectification. 
     The substrate which has been polished is returned to the reversing device  250  or  252  in the reverse route to the above. The substrate returned to the reversing device  250  or  252  is rinsed by pure water or chemicals supplied from rinsing nozzles. Further, the substrate holding surface of the top ring  208  or  210  from which the substrate has been removed is also cleaned by pure water or chemicals supplied from cleaning nozzles, and in some cases, the substrate holding surface of the top ring  208  or  210  is rinsed for preventing the substrate holding surface from being dried. A cleaning nozzle or nozzles for cleaning the pusher are provided on the partition wall. In order to improve yield of the semiconductor device or cleaning effect of the substrate, the substrate may be rinsed by chemicals in such a state that the substrate is held by the top ring  208  or  210 . Further, the substrate may be rinsed by chemicals in such a state that the substrate is held by the rotary transporter  258 . Further, the lifter  260  or  262  may be cleaned by nozzles (described later). 
     On the right side of  FIG. 8 , the relationship of the rotary transporter  258 , the reversing device  250  or  252 , the lifter  260  or  262 , and the pusher  264  or  266  is shown. As shown in  FIG. 8 , the reversing unit  250  or  252  is disposed above the rotary transporter  258 , and the lifters  260  or  262  and the pushers  264  or  266  are disposed below the rotary transporter  258 . 
     Next, transport routes for transporting substrates will be described. 
     All software is constructed such that all units or devices are freely combined and set in normal processing routes of the substrates in the polishing apparatus. Examples of the processing routes are the following: 
     1) Method (2 cassette parallel processing) in which substrates in one substrate cassette  22  are processed in one of the two areas C and D, and substrates in another substrate cassette  22  are processed in the other of the two areas C and D; 
     2) Method (1 cassette parallel processing) in which substrates in one substrate cassette  22  are distributed into the area C and the area D arbitrarily; and 
     3) Method (serial processing) in which substrates in one substrate cassette  22  are processed in one of the areas C and D, and then processed in the other of the areas C and D. 
     In the cleaning chamber, polished substrates discharged from the polishing chambers are processed according to any one of the following six processes: 
     A) Process in which substrates are cleaned in two-stages by two arrays of cleaning apparatuses and discharged, i.e., from the cleaning apparatus  182  to the cleaning apparatus  146  and from the cleaning apparatus  184  to the cleaning apparatus  148 ; 
     B) Process in which substrates are cleaned in three-stages by one array of cleaning apparatuses and discharged, i.e., from the cleaning apparatus  184  to the cleaning apparatus  148  and then to the cleaning apparatus  146  or in three-stages by one array of cleaning apparatuses and discharged, i.e., from the cleaning apparatus  182  to the cleaning apparatus  184  or  148  and then to the cleaning apparatus  146 ; 
     C) Process in which substrates are cleaned in three-stages and discharged, i.e., in one-stage by two cleaning apparatuses, i.e., either one of the cleaning apparatuses  182 ,  184  where no cleaning is being conducted, and in two-stages by one array of cleaning apparatuses, i.e., from the cleaning apparatus  148  to the cleaning apparatus  146 ; 
     D) Process in which substrates are cleaned in four-stages by one array of cleaning apparatuses and discharged, i.e., from the cleaning apparatus  184  to the cleaning apparatus  148  and then to the cleaning apparatus  182  and then to the cleaning apparatus  146 ; 
     E) Process in which substrates are cleaned in four-stages by one array of cleaning apparatuses and discharged, i.e., from the cleaning apparatus  182  to the cleaning apparatus  184  and then to the cleaning apparatus  148  and then to the cleaning apparatus  146 ; and 
     F) Process in which substrates are cleaned in three-stages by one array of cleaning apparatuses and discharged, i.e., from the cleaning apparatus  184  to the cleaning apparatus  148  and then to the cleaning apparatus  146 , after the substrates which have been polished in a first stage are cleaned by the cleaning apparatus  182  and then polished again in a second stage. 
     Combinations of the methods 1)–3) and the processes A)–F) provide their respective features as follows: 
     (1-A): 
     This combination is effective in a case where different processes are carried out for two substrate cassettes and a case where a plurality of lots of substrates are discharged at a high throughput. If different processes are carried out for the two substrate cassettes, then an apparatus configuration or arrangement provided by a combination of two dry-in and dry-out type polishing apparatuses, for example, is employed. Since this combination offers the greatest throughput, it is used to achieve a higher production capability with the same process being carried out on substrates from the two substrate cassettes. 
     (2-A): 
     This combination is effective to process substrates in one substrate cassette in a short period of time. This combination also allows substrates in one substrate cassette to be processed in two arbitrary different types of processes. 
     (3-A): 
     In the case where the time required to clean a substrate in at least one of the two cleaning stages is longer than the time required to polish a substrate in either one of the two polishing stages, if the two cleaning stages are carried out by one array of cleaning apparatuses, then the polishing capability is lowered because of the long cleaning time. In this case, if the two cleaning stages are carried out by two arrays of cleaning apparatuses, then polished substrates can be delivered without being affected by the cleaning time. This combination is highly effective in this case. 
     (1-B): 
     This combination is used in a case where three or more types of cleaning process are required after the polishing process. Since the cleaning process is carried out by one array of cleaning apparatuses, the processing capability of the cleaning process according to this combination is reduced, and the combination is highly effective in a case where the polishing time is longer than the cleaning time. 
     (2-B): 
     This combination is used in a case where only one lot is processed, but not a plurality of lots are processed at once as with the combination (1-B), and offers the same advantages as with the combination (1-B). 
     (3-B): 
     This combination is used in a case where three cleaning stages are needed as with the combination (1-B). 
     (1-C): 
     This combination offers the same advantages as with the combination (1-B). If the cleaning time in the first cleaning stage is longer than the processing time in another wafer processing unit, then the first cleaning stage is carried out by two cleaning apparatuses for preventing substrates from being jammed at the first cleaning apparatus, thereby increasing the processing capability. 
     (2-C): 
     As with the combination (1-C), this combination is used for the same reason as the combination (2-B). 
     (3-C): 
     As with the combination (1-C), this combination is used for the same reason as the combination (3-B). 
     (1, 2, 3-D, E): 
     This combination is used in a case where four cleaning stages are required in addition to the use of the respective polishing chambers. 
     (3-F): 
     In the two-stage polishing process, this combination is used to transport substrates through a cleaning process before the second polishing stage for preventing the substrates to which the abrasive liquid used in the first polishing stage is attached from being polished in the second polishing stage. 
     As described above, since the polishing apparatus according to the present invention has the two polishing sections having the respective turntables  200  and  204 , one of the polishing sections can be inspected and serviced for maintenance while the polishing apparatus is in operation using the other polishing section. 
     A cleaning section has the cleaning apparatuses  146 ,  148 ,  182  and  184  for cleaning substrates. While the polishing apparatus is in operation using at least one of the cleaning apparatuses, the other cleaning apparatuses can be inspected and serviced for maintenance. 
       FIG. 9  is a cross-sectional view showing a relationship between a top ring and a polishing table of the CMP device. As shown in  FIG. 9 , a polishing table  304  is disposed underneath a top ring  300 , and has a polishing pad  302  attached to an upper surface thereof. A polishing liquid supply nozzle  306  is disposed above the polishing table  304  and supplies a polishing liquid Q onto the polishing pad  302  on the polishing table  304 . 
     Various kinds of polishing pads are sold on the market. For example, some of these are SUBA800, IC-1000, and IC-1000/SUBA400 (two-layer cloth) manufactured by Rodel Inc., and Surfin xxx-5 and Surfin 000 manufactured by Fujimi Inc. SUBA800, Surfin xxx-5, and Surf in 000 are non-woven fabrics bonded by urethane resin, and IC-1000 is rigid foam polyurethane (single-layer). Foam polyurethane is porous and has a large number of fine recesses or holes formed in its surface. 
     The top ring  300  is connected to a top ring drive shaft  310  by a universal joint  308 . The top ring drive shaft  310  is coupled to a top ring air cylinder  314  fixed to a top ring head  312 . The top ring air cylinder  314  operates to vertically move the top ring drive shaft  310  to thus lift and lower the top ring  300  as a whole. The top ring air cylinder  314  also operates to press a retainer ring  318  fixed to the lower end of a top ring body  316  against the polishing table  304 . The top ring air cylinder  314  is connected to a compressed air source (fluid source)  320  via a regulator R 1 , which regulates the pressure of air supplied to the top ring air cylinder  314  for thereby adjusting a pressing force with which the retainer ring  318  presses the polishing pad  302 . 
     The top ring drive shaft  310  is connected to a rotary sleeve  322  by a key (not shown). The rotary sleeve  322  has a timing pulley  324  fixedly disposed therearound. A top ring motor  326  having a drive shaft is fixed to the upper surface of the top ring head  312 . The timing pulley  328  is operatively coupled to a timing pulley  324  mounted on the drive shaft of the top ring motor  326  by a timing belt  328 . When the top ring motor  326  is energized, the timing pulley  330 , the timing belt  328 , and the timing pulley  324  are rotated to rotate the rotary sleeve  322  and the top ring drive shaft  310  in unison, thus rotating the top ring  300 . The top ring head  312  is supported on a top ring head shaft  332  fixedly supported on a frame (not shown). 
       FIG. 10  is a vertical cross-sectional view showing the top ring  300 , and  FIG. 11  is a bottom view of the top ring  300  shown in  FIG. 10 . As shown in  FIG. 10 , the top ring  300  comprises the top ring body  316  in the form of a cylindrical housing with a storage space defined therein, and the retainer ring  318  fixed to the lower end of the top ring body  316 . The top ring body  316  is made of a material having high strength and rigidity, such as metal or ceramics. The retainer ring  318  is made of highly rigid synthetic resin, ceramics, or the like. 
     The top ring body  316  comprises a cylindrical housing  316   a , an annular pressurizing sheet support  316   b  fitted in the cylindrical housing  316   a , and an annular seal  316   c  fitted over an outer circumferential edge of an upper surface of the cylindrical housing  316   a . The retainer ring  316  is fixed to the lower end of the cylindrical housing  316   a  and has a lower portion projecting radially inwardly. The retainer ring  318  may be integrally formed with the top ring body  316 . 
     The top ring drive shaft  310  is disposed above the center of the cylindrical housing  316   a  of the top ring body  316 . The top ring body  316  is coupled to the top ring drive shaft  310  by the universal joint  310 . The universal joint  310  has a spherical bearing mechanism by which the top ring body  316  and the top ring drive shaft  310  are tiltable with respect to each other, and a rotation transmitting mechanism for transmitting the rotation of the top ring drive shaft  310  to the top ring body  316 . The rotation transmitting mechanism and the spherical bearing mechanism transmit pressing and rotating forces from the top ring drive shaft  310  to the top ring body  316  while allowing the top ring body  316  and the top ring drive shaft  310  to be tilted with respect to each other. 
     The spherical bearing mechanism comprises a spherical recess  310   a  defined centrally in the lower surface of the top ring drive shaft  310 , a spherical recess  316   d  defined centrally in the upper surface of the housing  316   a , and a bearing ball  334  made of a highly hard material such as ceramics and interposed between the spherical recesses  310   a  and  316   d . The rotation transmitting mechanism comprises a drive pin (not shown) fixed to the top ring drive shaft  310 , and a driven pin (not shown) fixed to the housing  316   a . The drive pin is held in driving engagement with the driven pin while the drive pin and the driven pin are being vertically movable relatively to each other. The rotation of the top ring drive shaft  310  is transmitted to the top ring body  316  through the drive and driven pins. Even when the top ring body  316  is tilted with respect to the top ring drive shaft  310 , the drive and driven pins remain in engagement with each other at a moving point of contact, so that the torque of the top ring drive shaft  310  can reliably be transmitted to the top ring body  316 . 
     The top ring body  316  and the retainer ring  318  secured to the top ring body  316  jointly have a space defined therein, which accommodates therein an elastic pad  336  having a lower end surface brought into contact with the upper surface of the substrate W held by the top ring  300 , an annular holder ring  340 , and a disk-shaped chucking plate (support member)  342  for supporting the elastic pad  336 . The elastic pad  336  has a radially outer edge clamped between the holder ring  340  and the chucking plate  342  secured to the lower end of the holder ring  340  and extends radially inwardly so as to cover the lower surface of the chucking plate  342 , thus forming a space between the elastic pad  336  and the chucking plate  342 . 
     The chucking plate  342  may be made of metal. However, when the thickness of a thin film formed on a surface of a substrate is measured by a method using eddy current in such a state that the substrate to be polished is held by the top ring, the chucking plate  342  should preferably be made of a non-magnetic material, e.g., an insulating material such as fluororesin or ceramics. 
     A pressurizing sheet  344 , which comprises an elastic membrane, extends between the holder ring  340  and the top ring body  316 . The pressurizing sheet  344  has a radially outer edge clamped between the housing  316   a  and the pressurizing sheet support  316   b  of the top ring body  316 , and a radially inner edge clamped between an upper portion  340   a  and a stopper  340   b  of the holder ring  340 . The top ring body  316 , the chucking plate  342 , the holder ring  340 , and the pressurizing sheet  344  jointly define a pressure chamber  346  in the top ring body  316 . As shown in  FIG. 10 , a fluid passage  348  comprising tubes and connectors communicates with the pressure chamber  346 , which is connected to the compressed air source  320  via a regulator R 2  connected to the fluid passage  348 . The pressurizing sheet  344  is made of a highly strong and durable rubber material such as ethylene propylene rubber (ethylene-propylene terpolymer (EPDM)), polyurethane rubber, silicone rubber, or the like. 
     In the case of a pressurizing sheet  344  made of an elastic material such as rubber, if the pressurizing sheet  344  is clamped between the retainer ring  318  and the top ring body  316 , then the pressurizing sheet  344  is elastically deformed as an elastic material, and a desired horizontal surface cannot be maintained on the lower surface of the retainer ring  318 . In order to maintain the desired horizontal surface on the lower surface of the retainer ring  318 , the pressurizing sheet  344  is clamped between the housing  316   a  of the top ring body  316  and the pressurizing sheet support  316   b  provided as a separate member in the present embodiment. The retainer ring  318  may vertically be movable with respect to the top ring body  316 , or the retainer ring  318  may have a structure capable of pressing the polishing surface independently of the top ring body  316 . In such cases, the pressurizing sheet  344  is not necessarily fixed in the aforementioned manner. 
     A cleaning liquid passage  350  in the form of an annular groove is defined in the upper surface of the housing  316   a  near its outer circumferential edge over which the seal  316   c  is fitted. The cleaning liquid passage  350  communicates with a fluid passage  354  via a through hole  352  formed in the seal  316   c , and is supplied with a cleaning liquid (pure water) via the fluid passage  354 . A plurality of communication holes  356  are defined in the housing  316   a  and the pressurizing sheet support  316   b  in communication with the cleaning liquid passage  350 . The communication holes  356  communicate with a small gap G defined between the outer circumferential surface of the elastic pad  336  and the inner circumferential surface of the retainer ring  318 . The fluid passage  354  is connected to a cleaning liquid source (not shown) through a rotary joint (not shown). 
     The space defined between the elastic pad  336  and the chucking plate  342  accommodates therein a central bag  360  as a central contact member brought into contact with the elastic pad  336 , and a ring tube  362  as an outer contact member brought into contact with the elastic pad  336 . These contact members may be brought into abutment against the elastic pad  336 . In the present embodiment, as shown in  FIGS. 10 and 11 , the central bag  360  having a circular contact surface is disposed centrally on the lower surface of the chucking plate  342 , and the ring tube  362  having an annular contact surface is disposed radially outwardly of the central bag  360  in surrounding relation thereto. Specifically, the central bag  360  and the ring tube  362  are spaced at predetermined intervals. Each of the elastic pad  336  and the central bag  360  and the ring tube  362  is made of a highly strong and durable rubber material such as ethylene propylene rubber (ethylene-propylene terpolymer (EPDM)), polyurethane rubber, silicone rubber, or the like. 
     The space defined between the chucking plate  342  and the elastic pad  336  is divided into a plurality of spaces (second pressure chambers) by the central bag  360  and the ring tube  362 . Specifically, a pressure chamber  364  is defined between the central bag  360  and the ring tube  362 , and a pressure chamber  366  is defined radially outwardly of the ring tube  362 . 
     The central bag  360  comprises an elastic membrane  368  brought into contact with the upper surface of the elastic pad  336 , and a central bag holder (holding member)  370  for detachably holding the elastic membrane  368  in position. The central bag holder  370  has threaded holes  370   a  defined therein, and is detachably fastened to the center of the lower surface of the chucking plate  342  by screws  372  threaded into the threaded holes  370   a . The central bag  360  has a central pressure chamber  374  (first pressure chamber) defined therein by the elastic membrane  368  and the central bag holder  370 . 
     Similarly, the ring tube  362  comprises an elastic membrane  376  brought into contact with the upper surface of the elastic pad  336 , and a ring tube holder (holding member)  378  for detachably holding the elastic membrane  376  in position. The ring tube holder  378  has threaded holes  378   a  defined therein, and is detachably fastened to the lower surface of the chucking plate  342  by screws  380  threaded into the threaded holes  378   a . The ring tube  362  has an intermediate pressure chamber  382  (first pressure chamber) defined therein by the elastic membrane  376  and the ring tube holder  378 . 
     Fluid passages  384 ,  386 ,  388  and  390  comprising tubes and connectors communicate with the pressure chambers  364 ,  366 , the central pressure chamber  374 , and the intermediate pressure chamber  382 , respectively. The pressure chambers  364 ,  366 ,  374  and  382  are connected to the compressed air source  320  via respective regulators R 3 , R 4 , R 5  and R 6  connected respectively to the fluid passages  384 ,  386 ,  388  and  390 . The fluid passages  348 ,  384 ,  386 ,  388  and  390  are connected to the respective regulators R 2 , R 3 , R 4 , R 5  and R 6  through a rotary joint (not shown) mounted on the upper end of the top ring drive shaft  310 . 
     The pressure chamber  346 ,  364 ,  366 ,  374  and  382  are supplied with a pressurized fluid such as pressurized air or atmospheric air or evacuated, via the fluid passages  348 ,  384 ,  386 ,  388  and  390 . As shown in  FIG. 9 , the regulators R 2  to R 6  connected to the fluid passages  348 ,  384 ,  386 ,  388  and  390  of the pressure chambers  346 ,  364 ,  366 ,  374  and  382  can respectively regulate the pressures of the pressurized fluids supplied to the pressure chambers  346 ,  364 ,  366 ,  374  and  382 , for thereby independently controlling the pressures in the pressure chambers  346 ,  364 ,  366 ,  374  and  382  or independently introducing atmospheric air or vacuum into the pressure chambers  346 ,  364 ,  366 ,  374  and  382 . Thus, the pressures in the pressure chambers  346 ,  364 ,  366 ,  374  and  382  are independently varied with the regulators R 2  to R 6 , so that the pressing forces, which are pressures per unit area for pressing the substrate W against the polishing pad  302 , can be adjusted in local areas of the substrate W via the elastic pad  336 . In some applications, the pressure chambers  346 ,  364 ,  366 ,  374  and  382  may be connected to a vacuum source  392 . 
     In this case, the pressurized fluid or the atmospheric air supplied to the pressure chambers  364 ,  366 ,  374  and  382  may independently be controlled in temperature, for thereby directly controlling the temperature of the substrate from the backside of the surface to be polished. Particularly, when each of the pressure chambers is independently controlled in temperature, the rate of chemical reaction can be controlled in the chemical polishing process of CMP. 
     As shown in  FIG. 11 , a plurality of openings  400  are formed in the elastic pad  336 . The chucking plate  342  has radially inner suction portions  402  and radially outer suction portions  404  extended downwardly therefrom. The openings  400  positioned between the central bag  360  and the ring tube  362  allow the inner suction portions  402  to be exposed externally, and the openings  400  positioned outside of the ring tube  362  allow the outer suction portions  404  to be exposed externally. In the present embodiment, the elastic pad  336  has eight openings  400  for allowing the eight suction portions  402 ,  404  to be exposed. 
     Each of the inner suction portions  402  has a hole  402   a  communicating with a fluid passage  406 , and each of the outer suction portions  404  has a hole  404   a  communicating with a fluid passage  408 . Thus, the inner suction portion  402  and the outer suction portion  404  are connected to the vacuum source  392  such as a vacuum pump via the respective fluid passages  406 ,  408  and valves V 1 , V 2 . When the suction portions  402 ,  404  are evacuated by the vacuum source  392  to develop a negative pressure at the lower opening ends of the communicating holes  402   a ,  404   a  thereof, a substrate W is attracted to the lower ends of the suction portions  402 ,  404  by the negative pressure. The suction portions  402 ,  404  have elastic sheets  402   b ,  404   b , such as thin rubber sheets, attached to their lower ends, for thereby elastically contacting and holding the substrate W on the lower surfaces thereof. 
     As shown in  FIG. 10 , when the substrate W is polished, the lower ends of the suction portions  402 ,  404  are positioned above the lower surface of the elastic pad  336 , without projecting downwardly from the lower surface of the elastic pad  336 . When the substrate W is attracted to the suction portions  402 ,  404 , the lower ends of the suction portions  402 ,  404  are positioned at the same level as the lower surface of the elastic pad  336 . 
     Since there is the small gap G between the outer circumferential surface of the elastic pad  336  and the inner circumferential surface of the retainer ring  318 , the holder ring  340 , the chucking plate  342 , and the elastic pad  336  attached to the chucking plate  342  can vertically be moved with respect to the top ring body  316  and the retainer ring  318 , and hence are of a floating structure with respect to the top ring body  316  and the retainer ring  318 . A plurality of teeth  340   c  project radially outwardly from the outer circumferential edge of the stopper  340   b  of the holder ring  340 . When the teeth  340   c  engage the upper surface of the radially inwardly projecting portion of the retainer ring  318  upon downward movement of the holder ring  340 , the holder ring  340  is limited against any further downward movement. 
     Operation of the top ring  300  thus constructed will be described below. 
     When the substrate W is to be delivered to the polishing apparatus, the top ring  300  is moved to a position to which the substrate W is transferred, and the communicating holes  402   a ,  404   a  of the suction portions  402 ,  404  are evacuated via the fluid passages  406 ,  408  by the vacuum source  392 . The substrate W is attracted to the lower ends of the suction portions  402 ,  404  by suction effect of the communicating holes  402   a ,  404   a . With the substrate W attracted to the top ring  300 , the top ring  300  is moved to a position above the polishing table  304  having the polishing surface (polishing pad  302 ) thereon. The retainer ring  318  holds the outer circumferential edge of the substrate W so that the substrate W is not removed from the top ring  300 . 
     For polishing the lower surface of the substrate W, the substrate W is thus held on the lower surface of the top ring  300 , and the top ring air cylinder  314  connected to the top ring drive shaft  310  is actuated to press the retainer ring  318  fixed to the lower end of the top ring  300  against the polishing surface on the polishing table  304  under a predetermined pressure. Then, the pressurized fluids are respectively supplied to the pressure chambers  364 ,  366 , the central pressure chamber  374 , and the intermediate pressure chamber  382  under respective pressures, thereby pressing the substrate W against the polishing surface on the polishing table  304 . The polishing liquid supply nozzle  306  then supplies the polishing liquid Q onto the polishing pad  302 . Thus, the substrate W is polished by the polishing pad  302  with the polishing liquid Q being present between the lower surface, to be polished, of the substrate W and the polishing pad  302 . 
     The local areas of the substrate W that are positioned beneath the pressure chambers  364 ,  366  are pressed against the polishing pad  302  under the pressures of the pressurized fluids supplied to the pressure chambers  364 ,  366 . The local area of the substrate W that is positioned beneath the central pressure chamber  374  is pressed via the elastic membrane  368  of the central bag  360  and the elastic pad  336  against the polishing pad  302  under the pressure of the pressurized fluid supplied to the central pressure chamber  374 . The local area of the substrate W that is positioned beneath the intermediate pressure chamber  382  is pressed via the elastic membrane  376  of the ring tube  362  and the elastic pad  336  against the polishing pad  302  under the pressure of the pressurized fluid supplied to the intermediate pressure chamber  382 . 
     Therefore, the polishing pressures acting on the respective local areas of the substrate W can be adjusted independently by controlling the pressures of the pressurized fluids supplied to each of the pressure chambers  364 ,  366 ,  374  and  382 . Specifically, each of the regulators R 3  to R 6  independently regulates the pressure of the pressurized fluid supplied to the pressure chambers  364 ,  366 ,  374  and  382  for thereby adjusting the pressing forces applied to press the local areas of the substrate W against the polishing pad  302  on the polishing table  304 . With the polishing pressures on the respective local areas of the substrate W being adjusted independently, the substrate W is pressed against the polishing pad  302  on the polishing table  304  that is being rotated. Similarly, the pressure of the pressurized fluid supplied to the top ring air cylinder  314  can be regulated by the regulator R 1  to adjust the force with which the retainer ring  318  presses the polishing pad  302 . While the substrate W is being polished, the force with which the retainer ring  318  presses the polishing pad  302  and the pressing force with which the substrate W is pressed against the polishing pad  302  can appropriately be adjusted for thereby applying polishing pressures in a desired pressure distribution to a central area C 1 , an inner area C 2 , an intermediate area C 3 , and a peripheral area C 4  of the substrate W (see  FIG. 11 ). 
     The local areas of the substrate W that are positioned beneath the pressure chambers  364 ,  366  are divided into areas to which a pressing force from a fluid is applied via the elastic pad  336 , and areas to which the pressure of a pressurized fluid is directly applied, such as areas positioned beneath the openings  400 . However, the pressing forces applied to these two areas are equal to each other. When the substrate W is polished, the elastic pad  336  is brought into close contact with the upper surface of the substrate W near the openings  400 , so that the pressurized fluids supplied to the pressure chambers  364 ,  366  are prevented from flowing out to the exterior. 
     In this manner, the substrate W is divided into the concentric circular and annular areas C 1  to C 4 , which can be pressed under independent pressing forces. The polishing rates of the circular and annular areas C 1  to C 4 , which depend on the pressing forces applied to those areas, can independently be controlled because the pressing forces applied to those areas can independently be controlled. Consequently, even if the thickness of a thin film to be polished on the surface of the substrate W suffers radial variations, the thin film on the surface of the substrate W can be polished uniformly without being insufficiently or excessively polished. More specifically, even if the thickness of the thin film to be polished on the surface of the substrate W differs depending on the radial position on the substrate W, the pressure in a pressure chamber positioned over a thicker area of the thin film is made higher than the pressure in a pressure chamber positioned over a thinner area of the thin film, or the pressure in a pressure chamber positioned over a thinner area of the thin film is made lower than the pressure in a pressure chamber positioned over a thicker area of the thin film. In this manner, the pressing force applied to the thicker area of the thin film is made higher than the pressing force applied to the thinner area of the thin film, thereby selectively increasing the polishing rate of the thicker area of the thin film. Consequently, the entire surface of the substrate W can be polished exactly to a desired level irrespective of the film thickness distribution obtained at the time the thin film is formed. 
     Any unwanted edge rounding on the circumferential edge of the substrate W can be prevented by controlling the pressing force applied to the retainer ring  318 . If the thin film to be polished on the circumferential edge of the substrate W has large thickness variations, then the pressing force applied to the retainer ring  318  is intentionally increased or reduced to thus control the polishing rate of the circumferential edge of the substrate W. When the pressurized fluids are supplied to the pressure chambers  364 ,  366 ,  374  and  382 , the chucking plate  342  is subjected to upward forces. In the present embodiment, the pressurized fluid is supplied to the pressure chamber  346  via the fluid passage  348  to prevent the chucking plate  342  from being lifted under the forces from the pressure chambers  364 ,  366 ,  374  and  382 . 
     As described above, the pressing force applied by the top ring air cylinder  314  to press the retainer ring  318  against the polishing pad  302  and the pressing forces applied by the pressurized fluids supplied to the pressure chambers  364 ,  366 ,  374  and  382  to press the local areas of the substrate W against the polishing pad  302  are appropriately adjusted to polish the substrate W. When the polishing of the substrate W is finished, the substrate W is attracted to the lower ends of the suction portions  402 ,  404  under vacuum in the same manner as described above. At this time, the supply of the pressurized fluids into the pressure chambers  364 ,  366 ,  374  and  382  is stopped, and the pressure chambers  364 ,  366 ,  374  and  382  are vented to the atmosphere. Accordingly, the lower ends of the suction portions  402 ,  404  are brought into contact with the substrate W. The pressure chamber  346  is vented to the atmosphere or evacuated to develop a negative pressure therein. If the pressure chamber  346  is maintained at a high pressure, then the substrate W is strongly pressed against the polishing surface only in areas brought into contact with the suction portions  402 ,  404 . Therefore, it is necessary to decrease the pressure in the pressure chamber  346  immediately. Accordingly, a relief port  410  penetrating through the top ring body  316  may be provided for decreasing the pressure in the pressure chamber  346  immediately, as shown in  FIG. 10 . In this case, when the pressure chamber  346  is pressurized, it is necessary to continuously supply the pressurized fluid into the pressure chamber  346  via the fluid passage  348 . The relief port  410  comprises a check valve (not shown) for preventing an outside air from flowing into the pressure chamber  346  at the time when a negative pressure is developed in the pressure chamber  346 . 
     After the substrate W is attracted to the lower ends of the suction portions  402 ,  404 , the entire top ring  300  is moved to a position to which the substrate W is to be transferred. Then, a fluid such as compressed air or a mixture of nitrogen and pure water is ejected to the substrate W via the communicating holes  402   a ,  404   a  of the suction portions  402 ,  404  to release the substrate W from the top ring  300 . 
     The polishing liquid Q used to polish the substrate W tends to flow through the gap G between the outer circumferential surface of the elastic pad  336  and the retainer ring  318 . If the polishing liquid Q is firmly deposited in the gap G, then the holder ring  340 , the chucking plate  342 , and the elastic pad  336  are prevented from smoothly moving vertically with respect to the top ring body  316  and the retainer ring  318 . To avoid such a drawback, a cleaning liquid (pure water) is supplied through the fluid passage  354  to the cleaning liquid passage  350 . Accordingly, the pure water is supplied via the communication holes  356  to a region above the gap G, thus cleaning members defining the gap G to remove deposits of the polishing liquid Q. The pure water should preferably be supplied after the polished substrate W is released and until a next substrate to be polished is attracted to the top ring  300 . It is also preferable to discharge all the supplied pure water out of the top ring  300  before the next substrate is polished, and hence to provide the retainer ring  318  with a plurality of through holes  318   a  shown in  FIG. 10  for discharging the pure water. Furthermore, if a pressure buildup is developed in a space  412  defined between the retainer ring  318 , the holder ring  340 , and the pressurizing sheet  344 , then it acts to prevent the chucking plate  342  from being elevated in the top ring body  316 . Therefore, in order to allow the chucking plate  342  to be elevated smoothly in the top ring body  316 , the through holes  318   a  should preferably be provided for equalizing the pressure in the space  412  with the atmospheric pressure. 
     As described above, according to the embodiment, the pressures in the pressure chambers  364 ,  366 , the pressure chamber  374  in the central bag  360 , and the pressure chamber  382  in the ring tube  362  are independently controlled to control the pressing forces acting on the substrate W. Further, according to the embodiment, regions in which a pressing force applied to the substrate W is controlled can easily be changed by changing positions or sizes of the central bag  360  and the ring tube  362 . Examples of changing the regions in which the pressing force applied to the substrate W is controlled will be described below. 
       FIGS. 12A through 12E  and  FIG. 13  are vertical cross-sectional views showing other examples of the contact members (central bag  360  and ring tube  362 ) in the substrate holder of a CMP device. 
     As shown in  FIGS. 12A and 12B , the area C 1  in which the pressing force applied to the substrate is controlled can be changed by another central bag  360  having a different size. In this case, when the size and shape of a hole  370   b  for allowing the pressure chamber  374  defined in the central bag  360  to communicate with the fluid passage  388 , and the size and position of the threaded holes  370   a  for mounting the central bag holder  370  on the chucking plate  342  are predetermined, the range in which the pressing force applied to the substrate is controlled can be changed simply by preparing a central bag holder  370  having a different size. In this case, it is not necessary to modify the chucking plate  342 . 
     As shown in  FIGS. 12C and 12D , the width and/or position of the area C 3  in which the pressing force applied to the substrate is controlled can be changed by another ring tube  362  having a different size and/or shape. Further, as shown in  FIG. 12E , a plurality of holes  414  and threaded holes (not shown) may be provided in predetermined radial positions of the chucking plate  342 . In this case, the communicating hole  378   b  is positioned at a position corresponding to one of the communicating holes  414 , and the other communicating holes (and threaded holes) are filled with screws  416  for sealing fluids. Thus, the ring tube  362  can flexibly be mounted in the radial direction, so that the region in which the pressing force is controlled can flexibly be changed. 
     As shown in  FIG. 13 , a protrusion  368   a  protruding radially outwardly from the circumferential edge of the elastic membrane  368  may be provided on the lower surface of the central bag  360 , and protrusions  376   a  protruding radially from the circumferential edges of the elastic membrane  376  may be provided on the lower surface of the ring tube  362 . The protrusions  368   a ,  376   a  are made of the same material as the central bag  360  and the ring tube  362 . As described above, when the substrate is polished, pressurized fluids are supplied to the pressure chamber  364  positioned between the central bag  360  and the ring tube  362 , and the pressure chamber  366  surrounding the ring tube  362 . Therefore, the protrusions  368   a ,  376   a  are brought into close contact with the elastic pad  336  by the pressurized fluids supplied to the pressure chambers  364 ,  366 . Thus, even if the pressure of the pressurized fluid supplied to the pressure chamber  364  adjacent to the central bag  360  is considerably higher than the pressure of the pressurized fluid supplied to the pressure chamber  374  defined in the central bag  360 , the high-pressure fluid adjacent to the central bag  360  is prevented from flowing into the lower portion of the central bag  360 . Similarly, even if the pressure of the pressurized fluid supplied to the pressure chamber  364  or  366  adjacent to the ring tube  362  is considerably higher than the pressure of the pressurized fluid supplied to the pressure chamber  382  defined in the ring tube  362 , the high-pressure fluid adjacent to the ring tube  362  is prevented from flowing into the lower portion of the ring tube  362 . Therefore, the protrusions  368   a ,  376   a  can widen the range of pressure control in each of the pressure chambers, for thereby pressing the substrate more stably. 
     The elastic membrane  368 ,  376  may have a partially different thickness or may partially include an inelastic member, so that deformations of the elastic membrane  368  of the central bag  360  and of the elastic membrane  376  of the ring tube  362  are ideal.  FIG. 14A  shows an example in which the elastic membrane  376  of the ring tube  362  has side surfaces  376   b  thicker than the surface brought into contact with the elastic pad  336 .  FIG. 14B  shows an example in which the elastic membrane  376  of the ring tube  362  partially includes inelastic members  376   d  in the side surfaces thereof. In these examples, deformation of the side surfaces of the elastic membrane due to the pressure in the pressure chambers can appropriately be limited. 
     As described above, the distribution of the thin film formed on the surface of the substrate varies depending on a deposition method or a deposition apparatus. According to the embodiment, a substrate holding apparatus can change the position and size of the pressure chambers for applying the pressing force to the substrate simply by change of the central bag  360  and the central bag holder  370 , or the ring tube  362  and the ring tube holder  378 . Therefore, the position and region in which the pressing force is controlled can easily be changed in accordance with the distribution of the thin film to be polished at low cost. In other words, the substrate holder can cope with various thickness distributions of the thin film formed on the substrate to be polished. The change of the shape and position of the central bag  360  or the ring tube  362  leads to the change of the size of the pressure chamber  364  positioned between the central bag  360  and the ring tube  362 , and the pressure chamber  366  surrounding the ring tube  362 . 
       FIG. 15  is a vertical cross-sectional view showing an another top ring  300  of a CMP device. The top ring  300  has a seal ring  420  instead of an elastic pad. The seal ring  420  comprises an elastic membrane covering only a lower surface of a chucking plate  342  near its outer circumferential edge. In this embodiment, neither an inner suction portion (indicated by the reference numeral  402  in  FIG. 10 ) nor an outer suction portion (indicated by the reference numeral  402  in  FIG. 10 ) is provided on the chucking plate  342 , for a simple configuration. However, suction portions for attracting a substrate may be provided on the chucking plate  342 , as described above. The seal ring  420  is made of a highly strong and durable rubber material such as ethylene propylene rubber (ethylene-propylene terpolymer (EPDM)), polyurethane rubber, silicone rubber, or the like. 
     The seal ring  420  is provided in such a state that the lower surface of the seal ring  420  is brought into contact with the upper surface of the substrate W. The seal ring  420  has a radially outer edge clamped between the chucking plate  342  and a holder ring  340 . The substrate W has a recess defined in an outer edge thereof, which is referred to as a notch or orientation flat, for recognizing or identifying the orientation of the substrate. Therefore, the seal ring  420  should preferably extend radially inwardly from the innermost position of the recess such a notch or orientation flat. 
     A central bag  360  is disposed centrally on the lower surface of the chucking plate  342 , and a ring tube  362  is disposed radially outwardly of the central bag  360  in surrounding relation thereto, as with described above. 
     In this embodiment, a substrate W to be polished is held by the top ring  300  in such a state that the substrate W is brought into contact with the seal ring  420 , an elastic membrane  368  of the central bag  360 , and an elastic membrane  376  of the ring tube  362 . Therefore, the substrate W the chucking plate  342 , and the seal ring  420  jointly define a space therebetween. This space is divided into a plurality of spaces (second pressure chambers) by the central bag  360  and the ring tube  362 . Specifically, a pressure chamber  364  is defined between the central bag  360  and the ring tube  362 , and a pressure chamber  366  is defined radially outwardly of the ring tube  362 . 
     Fluid passages  384 ,  386 ,  388  and  390  comprising tubes and connectors communicate with the pressure chambers  364 ,  366 , a central pressure chamber (first pressure chamber)  374  defined in the central bag  360 , and an intermediate pressure chamber (first pressure chamber)  382  defined in the ring tube  362 , respectively. The pressure chambers  364 ,  366 ,  374  and  382  are connected to the compressed air source via respective regulators connected respectively to the fluid passages  384 ,  386 ,  388  and  390 . The regulators connected to the fluid passages  348 ,  384 ,  386 ,  388  and  390  of the pressure chambers  346 ,  364 ,  366 ,  374  and  382  can respectively regulate the pressures of the pressurized fluids supplied to the pressure chambers  346 ,  364 ,  366 ,  374  and  382 , for thereby independently controlling the pressures in the pressure chambers  346 ,  364 ,  366 ,  374  and  382  or independently introducing atmospheric air or vacuum into the pressure chambers  346 ,  364 ,  366 ,  374  and  382 . Thus, the pressures in the pressure chambers  346 ,  364 ,  366 ,  374  and  382  are independently varied with the regulators, so that the pressing forces can be adjusted in local areas of the substrate W. In some applications, the pressure chambers  346 ,  364 ,  366 ,  374  and  382  may be connected to a vacuum source  392 . 
     Operation of the top ring  300  thus constructed will be described below. 
     When the substrate W is to be delivered to the polishing apparatus, the top ring  300  is moved to a position to which the substrate W is delivered, and the central bag  360  and the ring tube  362  are supplied with a pressurized fluid under a predetermined pressure for bringing the lower surfaces of the central bag  360  and the ring tube  362  into close contact with the upper surface of the substrate W. Thereafter, the pressure chambers  364 ,  366  are connected to a vacuum source via the fluid passages  384 ,  386  to develop a negative pressure in the pressure chambers  364 ,  366  for thereby attracting the substrate W under vacuum. 
     For polishing the lower surface of the substrate W, the substrate W is thus held on the lower surface of the top ring  300 , and the top ring air cylinder  314  connected to the top ring drive shaft  310  is actuated to press the retainer ring  318  fixed to the lower end of the top ring  300  against the polishing surface on the polishing table  304  under a predetermined pressure. Then, the pressurized fluids are respectively supplied to the pressure chambers  364 ,  366 , the central pressure chamber  374 , and the intermediate pressure chamber  382  under respective pressures, thereby pressing the substrate W against the polishing surface on the polishing table  304 . The polishing liquid supply nozzle  306  then supplies the polishing liquid Q onto the polishing pad  302 . Thus, the substrate W is polished by the polishing pad  302  with the polishing liquid Q being present between the lower surface, to be polished, of the substrate W and the polishing pad  302 . 
     The local areas of the substrate W that are positioned beneath the pressure chambers  364 ,  366  are pressed against the polishing pad  302  under the pressures of the pressurized fluids supplied to the pressure chambers  364 ,  366 . The local area of the substrate W that is positioned beneath the central pressure chamber  374  is pressed via the elastic membrane  368  of the central bag  360  against the polishing pad  302  under the pressure of the pressurized fluid supplied to the central pressure chamber  374 . The local area of the substrate W that is positioned beneath the intermediate pressure chamber  382  is pressed via the elastic membrane  376  of the ring tube  362  against the polishing pad  302  under the pressure of the pressurized fluid supplied to the intermediate pressure chamber  382 . 
     Therefore, the polishing pressures acting on the respective local areas of the substrate W can be adjusted independently by controlling the pressures of the pressurized fluids supplied to each of the pressure chambers  364 ,  366 ,  374  and  382 . Thus, the substrate W is divided into the concentric circular and annular areas, which can be pressed under independent pressing forces. The polishing rates of the circular and annular areas, which depend on the pressing forces applied to those areas, can independently be controlled because the pressing forces applied to those areas can independently be controlled. Consequently, even if the thickness of a thin film to be polished on the surface of the substrate W suffers radial variations, the thin film on the surface of the substrate W can be polished uniformly without being insufficiently or excessively polished. More specifically, even if the thickness of the thin film to be polished on the surface of the substrate W differs depending on the radial position on the substrate W, the pressure in a pressure chamber positioned over a thicker area of the thin film is made higher than the pressure in a pressure chamber positioned over a thinner area of the thin film, or the pressure in a pressure chamber positioned over a thinner area of the thin film is made lower than the pressure in a pressure chamber positioned over a thicker area of the thin film. In this manner, the pressing force applied to the thicker area of the thin film is made higher than the pressing force applied to the thinner area of the thin film, thereby selectively increasing the polishing rate of the thicker area of the thin film. Consequently, the entire surface of the substrate W can be polished exactly to a desired level irrespective of the film thickness distribution obtained at the time the thin film is formed. 
     When the substrate W is polished, the seal ring  420  is brought into close contact with a part of the upper surface of the substrate for thereby sealing this space. Hence, the pressurized fluid is prevented from flowing out to the exterior of the pressure chamber  366 . 
     When the polishing of the substrate W is finished, the substrate W is attracted under vacuum in the same manner as described above, and then the pressure chamber  346  is vented to the atmosphere or evacuated to develop a negative pressure therein. After the substrate W is attracted, the entire top ring  300  is moved to a position from which the substrate W is to be delivered. Then, a fluid such as compressed air or a mixture of nitrogen and pure water is ejected to the substrate W via the fluid passages  384 ,  386  to release the substrate W from the top ring  300 . If the elastic membrane  368  of the central bag  360  and the elastic membrane  376  of the ring tube  362  have through holes defined in their lower surfaces, then since downward forces are applied to the substrate W by the fluid flowing through these through holes, the substrate W can be smoothly released from the top ring  300 . After the substrate W is released from the top ring  300 , most of the lower surface of the top ring  300  is exposed. Therefore, the lower surface of the top ring  300  can be cleaned relatively easily after the substrate W is polished and released. 
     In the embodiments described above, the fluid passages  348 ,  384 ,  386 ,  388  and  390  are provided as separate passages. However, the arrangement of the fluid passages and the pressure chambers may be modified in accordance with the magnitude of the pressing force to be applied to the substrate W and the position to which the pressing force is applied. For example, these passages may be joined to each other, or the pressure chambers may be connected to each other. 
     The pressure chambers  364 ,  366  may be connected to the pressure chamber  346  to form one pressure chamber, without the fluid passage  384  communicating with the pressure chamber  364  and the fluid passage  386  communicating with the pressure chamber  366 . In this case, the pressures in the pressure chambers  346 ,  364 ,  366  are controlled at an equal pressure by a pressurized fluid supplied via the fluid passage  348 . If it is not necessary to provide a pressure difference between the pressure chamber  364  and the pressure chamber  366 , and the pressures in the central pressure chamber  374  and the intermediate pressure chamber  382  are not larger than the pressures in the pressure chambers  346 ,  364 ,  366 , then the above arrangement can be adopted to dispense with the fluid passages  384 ,  386 , for thereby decreasing the number of the fluid passages and simplifying the fluid passages. 
     When the inner suction portions  402  and the outer suction portions  404  are provided on the chucking plate  342 , as shown in  FIGS. 10 and 11 , not only a vacuum is created in the fluid passages  406 ,  408  communicating with the suction portions  402 ,  404 , but also pressurized fluids may be supplied to the fluid passages  406 ,  408 . In this case, suction of the substrate in the suction portions  402 ,  404  and supply of the pressurized fluids to the pressure chambers  364 ,  366  can be performed with one respective passage. Hence, it is not necessary to provide two fluid passages, i.e., the fluid passages  384 ,  386 , for thereby decreasing the number of the fluid passages and simplifying the fluid passages. 
     The chucking plate  342  has a protuberance  422  projecting downwardly from the outer circumferential edge thereof for maintaining the shape of the lower peripheral portion of the elastic membrane  336  or the seal ring  420  (see  FIGS. 10 and 15 ). However, if it is not necessary to maintain the shape of the elastic membrane  336  or the seal ring  420  because of its material or the like, then the chucking plate  342  does not need to have such a protuberance.  FIG. 16  is a vertical cross-sectional view showing a top ring  300  in which the chucking plate  342  has no protuberance  422  in the embodiment shown in  FIGS. 10 and 11 . In this case, the substrate W can uniformly-be pressed from the central portion thereof to the outer peripheral portion thereof. Further, the substrate can easily follow the large waviness or undulation on the polishing surface by omitting the protuberance  422 . 
     In the embodiments described above, the polishing surface is constituted by the polishing pad. However, the polishing surface is not limited to this. For example, the polishing surface may be constituted by a fixed abrasive. The fixed abrasive is formed into a flat plate comprising abrasive particles fixed by a binder. With the fixed abrasive, the polishing process is performed by the abrasive particles self-generated from the fixed abrasive. The fixed abrasive comprises abrasive particles, a binder, and pores. For example, cerium dioxide (CeO 2 ) having an average particle diameter of 0.5 μm is used as an abrasive particle, and epoxy resin is used as a binder. Such a fixed abrasive forms a harder polishing surface. The fixed abrasive includes a fixed abrasive pad having a two-layer structure formed by a thin layer of a fixed abrasive and an elastic polishing pad attached to the layer of the fixed abrasive. IC-1000 described above may be used for another hard polishing surface. 
       FIGS. 17 and 18  show an example of the substrate transport box  24  in which the substrate cassette  22  accommodating the substrates W with the exposed copper film on the surface thereof is housed and sealed up, and the substrates W in the enclosed state are transported together with the substrate cassette  22 . The substrate transport box  24  comprises general SMIF or HOOP. A particle removal filter and a fan motor may be installed within the substrate transport box  24  to circulate and purify the gas inside the substrate transport box  24 , whereby cross contamination between the substrates can be prevented. Also, particles and ions can be removed by installing both of a chemisorption filter and a particle filter inside the substrate transport box  24 . Of course, only a particle filter, and a deionization filter as a chemical filter may be used. When a fan motor, etc. are installed in the substrate transport box  24 , it is permissible to flow an electric current from a socket-outlet provided in a base member or the like when the substrate transport box  24  is mounted on the base member or the like, thereby rotating the fan motor, instead of providing batteries inside the substrate transport box  24 . 
     Furthermore, the occurrence of an oxide film can be prevented by providing dehumidification means, such as a dehumidifying agent, in the substrate transport box  24  to control the humidity inside the substrate transport box  24 . In this case, the humidity inside the substrate transport box  24  is decreased, preferably, to 10% or less, and more preferably, to 5% or less. If there is a possibility for destruction of the semiconductor device by generation of static electricity at a low humidity, it is desirable that the copper surface of each substrate be grounded to allow the static electricity to escape while the substrate is transported and/or stored. 
     The interior of the substrate transport box  24  is normally filled with air, but the use of an inert gas or the like with a restricted amount of oxygen can prevent oxidation of copper. The amount of oxygen is preferably 10,000 ppm or less, more preferably 1,000 ppm or less. 
       FIGS. 19 to 22  show other example of the substrate transport box  24 . This substrate transport box  24 , for example, serves to transport and store a plurality of 300 mm substrates W accommodated in groove-shaped pockets  504  fixed to the inside of a box body  501 . The substrate transport box  24  comprises a rectangular tubular box body  501 , a substrate carry-in/carry-out door  502  for mechanically opening/closing an opening portion formed in a side surface of the box body  501  by connected to a substrate carry-in/carry-out door automatic opening/closing device, a closure  503  located on a side opposite to the opening portion and adapted to cover an opening for mounting and dismounting filters and a fan motor, groove-shaped pockets  504  for holding substrates W, a ULPA filter  505 , a chemical filter  506 , and a fan motor  507 . 
     The substrate carry-in/carry-out door  502  can be opened and closed mechanically. V grooves  509  for engagement with kinematic coupling pins  508  (see  FIG. 23 ) for performing high accuracy positioning at the substrate carry-in/carry-out door automatic opening/closing device are provided at the bottom of the box body  501 . Positioning pin receiving portions  510 , and accepting portions  511  into which latch keys for opening/closing the door are inserted are provided in the substrate carry-in/carry-out door  502  so that automatic opening/closing can be done from the substrate carry-in/carry-out door automatic opening/closing device side. Also, a robotic handling flange  512  is provided so that transport can be performed using a transport device such as OHT (overhead hoist transport) or AGV (automatic guided vehicle). The V grooves  509 , positioning pin receiving portions  510 , accepting portions  511  into which latch keys for opening/closing the door are inserted, robotic handling flange  512 , and other matters concerned with automated interface are designed in compliance with SEMI Standards E1.9, E47.1, E57 and E62. 
     The interior of the box body  501  is partitioned into a central chamber  513   a  at the center, and a pair of side chambers  513   b  located on both sides of the central chamber  513   a , by a partition plate  530 . The partition plate  530  integrated with the right and left groove-shaped pockets  504  as pairs is positioned to have gaps between the substrate carry-in/carry-out door  502  and the closure  503 . The groove-shaped pockets  504  having taper portions fanning out toward the door so as to engage the substrates W are integrally provided in a portion of the partition plate  530  facing the substrate carry-in/carry-out door  502 . 
     In a portion of the central chamber  513   a  facing the closure  503 , the ULPA filter  505  constituting a particle removing filter mainly intended to remove particles, and the chemical filter  506  constituting a gaseous impurities trapping filter for removing impurity gases are disposed such that air can flow from the closure  503  toward the substrate carry-in/carry-out door  502 . Upstream from the trapping filter  506 , the fan motor  507  is disposed so as to send air toward the substrate carry-in/carry-out door  502 . 
     Opposite end portions of the substrate carry-in/carry-out door  502  are in an inwardly smoothly curved form, and a triangular stream regulating plate  514  is provided at the center of the substrate carry-in/carry-out door  502 . The substrate carry-in/carry-out door  502  is also equipped with fixing jigs  515  for preventing displacement of the substrate. Similarly, an inner surface of the closure  503  is in an inwardly curved form, and a triangular stream regulating plate  516  is provided at the center of the closure  503 . Furthermore, stream regulating plates  517  intended to supply clean air uniformly to the plurality of substrates W are mounted at two locations adjacent to the inward clean air supply opening. 
     When  25  of the substrates W are accommodated, for example, the gap between each of the first and twenty-fifth substrates W and the inner wall surface of the substrate transport box  24  is set to be wider than the spacing between the other adjacent substrates W. With this arrangement, the supply of a uniform flow rate to the substrates W is inhibited, but the provision of the stream regulating plates  517  at the inward clean air supply opening uniformizes the flow rate between each of the first and twenty-fifth substrates W and the carrier body relative to the flow rate between the adjacent substrates, thereby performing purification efficiently. 
     A power supply unit  518  incorporating a secondary battery is disposed at the bottom of the closure  503 , and has a contact for connection to a terminal  519  of the fan motor  507 . An operation control substrate for the fan motor  507  is incorporated in the power supply unit  518 . The fan motor  507  is controlled in terms of the timings of operation and stoppage and the number of rotations in compliance with control programs which have been programmed in the control substrate. A charging terminal  520  is provided at the bottom of the power supply unit  518 . When the substrate transport box  24  is seated on the substrate carry-in/carry-out door automatic opening/closing device or on a charging station, the charging terminal  520  is connected to the terminal present in this device, whereby the secondary battery can be charged automatically. 
     The gaseous impurities trapping filter  506 , in the present embodiment, is constituted by wrapping particulate activated carbon for organic substrate removal in an ion exchange unwoven fabric for inorganic ions removal. The medium may be pulverized activated carbon, activated carbon fibers, high purity silicon, zeolite, ceramic or impregnation activated carbon. The activated carbon fibers can be obtained by shaping rayon, kainol, polyacrylonitrile, petroleum, or petroleum pitch into a fibrous form, and subjecting the fibrous carbonaceous material to a so-called activation reaction, i.e., a gasification reaction with steam or carbon dioxide at a high temperature of 800° C. or higher. The activated carbon fibers may contain a binder or the like, which does not contribute to adsorption, for the purpose of maintaining strength and preventing dust generation. However, a lower content of the binder or the like is desirable as a material. 
     Activated carbon has many pores among the basic crystals, because unstructured carbon, etc. have-been removed during the process of activation. These pores and a large specific surface area impart high physical adsorptivity to activated carbon. An activated carbon filter filled with particulate activated carbon taking advantage of the above property is commercially available. Also on the market, as film materials for an air filter are a filter comprising activated carbon fibers with little dust formation, high workability, finer pores than particulate activated carbon, and a large specific surface area, and a filter having particulate activated carbon of about 0.5 mm in diameter carried on a urethane foam of an open porous structure. 
     High purity silicon, the same material as that of the semiconductor substrate, can be used as an adsorbent. The surface state of high purity silicon comes in two types, hydrophilic and hydrophobic, and the hydrophilic and hydrophobic ones are different in adsorption properties. Generally, the hydrophobic surface washed with dilute hydrofluoric acid is susceptible to environment, and shows high adsorbing properties toward hydrocarbon even at a very low concentration. However, the hydrophobic-surface silicon changes into a hydrophilic surface as an oxide film grows. Thus, the hydrophobic-surface silicon has the drawback of the adsorption properties changing over time. The hydrophilic surface highly adsorbs an organic substance having polarity, for example, BHT (2,6-di-t-butyl-p-cresol) or DBP (dibutyl phthalate). Either high purity silicon is effectively used not alone, but in combination with activated carbon. 
     The ion exchange unwoven fabric or fibers can be obtained, for example, by introducing ion exchange groups by a radiation graft polymerization reaction. That is, a base material composed of an organic polymer, for example, a polymer such as polyethylene or polypropylene, or a naturally occurring high molecular fiber or woven fabric, such as cotton or wool, is irradiated with radiation, such as electron rays or gamma rays, to generate many active points. These active points have very high activity, and are called radicals. A monomer is chemically bonded to these radicals, whereby the properties of the monomer which are different from the properties of the base material can be imparted. 
     This technique grafts the monomer to the base material, and thus is called graft polymerization. When a monomer having a sulfone group, carboxyl group, amino group or the like, which is an ion exchange group, for example, sodium styrenesulfonate, acrylic acid, or arylamine, is bonded to the polyethylene unwoven fabric base material by radiation graft polymerization, there can be obtained an unwoven fabric type ion exchanger with a much higher ion exchange rate than ion exchange beads usually called an ion exchange resin. 
     Similarly, a monomer capable of accepting an ion exchange group, such as styrene, chloromethylstyrene, glycidyl methacrylate, acrylonitrile, or acrolein, may be radiation graft polymerized with the base material, and then an ion exchange group may be introduced. In this case as well, an ion exchanger can be prepared in the form of the base material. 
     For a filter medium of a ULPA filter or HEPA filter, glass fibers have been used. However, it has been found that glass fibers react with a hydrogen fluoride (HF) vapor used in the manufacturing process for a semiconductor device to produce BF 3 , thus posing a problem. In recent years, a ULPA filter and an HEPA filter using as a filter medium PTFE (polytetrafluoroethylene), which is free from impurities such as boron or metal and is unaffected by acids, alkalis, and organic solvents, have been marketed. Glass fibers or PTFE may be selected as the need arises. 
     Actions to be done when the substrate transport box  24  accommodating a plurality of substrates W is carried in the copper plating device  18  shown in  FIG. 1 , for example, will be described with reference to  FIG. 23 . 
     The copper plating device  18  has a substrate carry-in/carry-out door automatic opening/closing device. When the substrate transport box  24  is transported into the copper plating device  18 , it is placed at a predetermined position. When the substrate transport box  24  is cut off from the clean room via a gate valve or the like, the substrate carry-in/carry-out door automatic opening/closing device opens the substrate carry-in/carry-out door  502 . Then, the substrate W is withdrawn by a substrate handling robot  521  within the plating device  18 , and processed. The substrate W after process is returned to the substrate transport box  24 . After process of all the substrates W is completed, the substrate carry-in/carry-out door  502  is closed by the substrate carry-in/carry-out door automatic opening/closing device to seal up the substrate transport box  24 . From this moment onward, an operation of the fan motor  507  is started to purify air inside the substrate transport box  24 . When the substrate carry-in/carry-out door  502  is closed, the substrate transport box  24  is transported to a subsequent process or device, or a storage warehouse by OHT or AGV. 
     The fan motor  507  is operated in accordance with a preset program, whereby a flow of air from the fan motor  507  to the gaseous impurities trapping filter (chemical filter)  506 , ULPA filter  505 , and central chamber  513   a  occurs. Air flowing into the central chamber  513   a  is smoothly bifurcated by the stream regulating plate  514  provided at the substrate carry-in/carry-out door  502 , and the respective air streams pass through the side chambers  513   b  and return to the fan motor  507 . In this manner, a circulation path of air is formed. 
     Air is purified while being passed through the gaseous impurities trapping filter  506  and ULPA filter  505 , and is then guided into the gaps among the substrates W by the inlet stream regulating plates  517  positioned at the inside of the opening of the partition plate  530  integrated with the groove-shaped pockets  504 . By providing the inlet stream regulating plates  517 , air is prevented from excessively flowing into the gaps between the substrates W and the partition plate  530  integrated with the groove-shaped pockets  504 . Air which has passed between the substrates W flows along the inner surfaces of the stream regulating plate  514  and the substrate carry-in/carry-out door  502 , changes in direction to reverse, passes through the side chambers  513   b , and returns to the fan motor  507 . 
     During this process, solid substances adhering to various parts, such as particles, or gaseous substances resulting therefrom are carried by the circulating air flow. The circulating air flow is purified by the two filters  505  and  506  located upstream from the substrates W, and comes to the substrates W. Thus, not only contamination from the outside, but also so-called self-contamination with objects present inside the substrate transport box  24  is prevented. 
     The operation pattern of the fan motor  507  may be considered in suitable modes adapted to the status of use of the substrate transport box  24 . Generally, the operation is performed continuously or at a high flow velocity in the initial stage to positively eliminate contamination which has been brought into the substrate transport box  24 . After a certain period of time elapses, the flow velocity is decreased, or the operation is carried out intermittently to prevent contamination occurring from the substrates W housed in the substrate transfer box  24  and the components installed inside the substrate transport box  24 . By this classified operation, the electric power consumption of the fan motor  507  can be decreased, with the result that the charging frequency for the secondary battery can be diminished. 
     When the substrate transport box  24  is set at a width W of 389.5 mm, a depth D of 450 mm, and a height H of 335 mm, and 25 of the substrates measuring 300 mm are housed in the substrate transport box  24 , the total weight including the substrates W is about 10 kg. In the present embodiment, by actuating the fan motor  507 , circulating air in an air volume of 0.12 m 3 /min can be flowed in the substrate transport box  24  so that the velocity of air passing through the center of the gap between the substrates W will be 0.03 m/s. The circulating air volume can be increased or decreased by changing the fan motor  507 . 
       FIGS. 24 and 25  show still another example of the substrate transport box  24 . The differences of this example from the example shown in  FIGS. 19 to 22  are that the size of the substrate W is 200 mm, that a door  523  for mechanical interface is located at the bottom of the box, and that the substrates W are housed in a substrate cassette  22  and, in this condition, accommodated in the substrate transport box  24 . The method of purifying air in the substrate transport box  24  is the same as in the example shown in  FIGS. 19 to 22 . In this example, a secondary battery for driving the fan motor  507  and a fan motor control circuit are incorporated in the box door  523 . 
     When the substrate transport box  24  is set at a width W of 283 mm, a depth D of 342 mm, and a height H of 254 mm, and 25 of the substrates measuring 200 mm are housed in the substrate transport box  24 , the total weight including the substrates W and the substrate cassette  22  is about 6 kg. In the present example, by actuating the fan motor  507 , circulating air in an air volume of 0.05 m 3 /min can be flowed in the substrate transport box  24  so that the velocity of air passing through the center of the gap between the substrates W will be 0.03 m/s. 
       FIG. 26  shows the entire constitution of another substrate processing apparatus of the present invention. The copper film (plated copper film)  6  shown in  FIG. 62B  is formed by use of a copper plating device  620  having a film thickness distribution adjusting function. The thickness of the copper film (plated copper film)  6  on the surface of the substrate is generally equal to or less than 2 micron meter, preferably equal to or less than 1 micron meter. The film thickness distribution of the copper film  6  over the entire surface is measured with a film thickness distribution measuring device  622 . Chemical mechanical polishing is applied to the surface of the substrate by a polishing device (CMP device)  624  having a polishing amount adjusting function to form a copper interconnection composed of the copper film  6  as shown in  FIG. 62C . For this procedure, based on the results of measurement by the film thickness distribution measuring device  622 , control signals, such as an electric field control signal and a plating time control signal, are inputted into the copper plating device  620  to control the copper plating device  620 , and control signals, such as a press control signal, are inputted into the CMP device  624  to control the CMP device  624 . 
     Details of the control are as follows: For the copper plating device  620 , the film thickness distribution of the copper film (plated copper film)  6  over the entire surface formed on the substrate is measured with the film thickness distribution measuring device  622  making use of, for example, the principle of eddy current thickness testing to find the difference between the film thickness of the copper film (plated copper film)  6  at the center of the substrate and the film thickness on the periphery of the substrate. Based on the results obtained, the copper plating device  620  is feedback controlled so that a plated copper film with a more uniform thickness will be deposited on the surface of the substrate to be processed after the target substrate measured, namely, that the difference between the film thickness of the plated copper film at the center of the substrate and the film thickness on the periphery of the substrate will be minimized. For the CMP device  624  as a subsequent processing step, the amounts of polishing at the center and on the periphery of the substrate are adjusted based on the results of measurements of the film thickness distribution over the entire surface, for example, by adjusting the pressure imposed on the center and the periphery of the substrate, whereby a flat copper film (plated copper film)  6  is finally obtained after polishing. 
     As described above, the copper plating device  620  having the film thickness distribution adjusting function is used, and feedback controlled to deposit a plated copper film more uniformly on the surface of the substrate. Furthermore, the CMP device  624  having the polishing amount adjusting function is used, and the amount of polishing of the plated copper film is adjusted based on the actual measurements of the film thickness distribution, whereby a flat plated copper film can be obtained finally. 
     As shown in  FIG. 27 , the film thickness distributions over the entire surface at the center and the periphery of the plated copper film after polishing with the CMP device  624  may be measured with a film thickness distribution measuring device  626 , and based on the results of these measurements, the CMP device  624  may be feedback controlled (for fine adjustment of the pressure against the substrate). 
       FIGS. 28 to 40  show different examples of the copper plating device  620  having the film thickness distribution adjusting mechanism. Members identical with or corresponding to the members of the conventional example shown in  FIG. 64  will be assigned the same numerals, and their explanation will be omitted partially. 
       FIG. 28  shows a copper plating device  620  which includes a flat plate-shaped, high resistance structure (virtual anode)  630  disposed between an anode plate (anode)  606  immersed in a plating liquid  600  in a plating tank  602 , and a substrate W held by a substrate holder  604  and disposed in an upper part of the plating tank  602 . The high resistance structure  630  has higher electrical resistivity than that of the plating liquid  600 , and comprises, for example, a film or a ceramic plate. The high resistance structure  630  is placed parallel to the anode plate  606  over the entire region of a cross section of the plating tank  602 . 
     According to this arrangement, the electric resistance between the anode plate  606  and the copper seed layer  7  (see  FIG. 62A ) formed on the surface (lower surface) of the substrate W can be made higher via the high resistance structure  630  than the electric resistance produced when the gap between them consists of the copper plating liquid  600  alone. This can diminish the difference in electric current density over the entire surface due to the influence of the electric resistance of the copper seed layer  7  formed on the surface of the substrate W. Consequently, the influence of the electric resistance of the copper seed layer can be decreased, without fully lengthening the distance between the anode plate  606  and the substrate W, so that the film thickness of the plated copper film can be rendered more uniform. 
       FIG. 29  shows a copper plating device  620  which includes a flat plate-shaped insulator (virtual anode)  632  placed between an anode plate  606  and a substrate W parallel to them instead of the high resistance structure  630  in  FIG. 28 . The insulator  632  has a central hole  632   a  at the center, and is a size smaller than the cross section of a plating tank  602 . Because of this insulator  632 , a plating electric current flows only through the interior of the central hole  632   a  of the insulator  632  and through the gaps between the outer peripheral end surface of the insulator  632  and the inner circumferential surface of the plating tank  602 , thereby thickening a plated copper film deposited, particularly, at the center of the substrate W. 
       FIG. 30  shows a copper plating device  620  which includes the insulator  632  of  FIG. 29  having a larger size, and having an outer peripheral end surface brought into contact with the inner circumferential surface of the plating tank  602 . Because of this configuration, a plating electric current flows only through the interior of the central hole  632   a  of the insulator  632 , thereby further thickening a plated copper film deposited at the center of the substrate W. 
       FIG. 31  shows a copper plating device  620  which includes a conductor (virtual anode)  634  placed between an anode plate  606  and a substrate W at a position corresponding to the center of the substrate W. The conductor  634  has lower electric resistivity than that of a plating liquid  600 . More plating electric current flows through the conductor  634 , thereby making a thicker plated copper film deposited at the center of the substrate W. 
       FIG. 32  is a modification of  FIG. 29 , showing a copper plating device  620  which includes an insulator  632  having a plurality of through-holes  632   b  of an arbitrary size (internal diameter) at arbitrary positions thereof. Because of this configuration, a plating electric current flows only through the interior of the through-holes  632   b , thereby making larger the film thickness of a plated copper film at the arbitrary positions of the substrate W. 
       FIG. 33  is a modification of  FIG. 32 , showing a copper plating device  620  which includes insulator having a plurality of through-holes  632   b  of an arbitrary size at arbitrary positions thereof, and a conductor  636  buried in the arbitrary through-hole  632   b . According to this configuration, a greater plating electric current flows through the interior of the conductor  636  than through the interior of the conductor-free through-holes  632   b , thereby depositing a copper film of a larger thickness at the arbitrary position of the substrate W. 
       FIG. 34  shows a modification of  FIG. 28 , showing a copper plating device  620  which includes a high resistance structure  630  having higher electric resistivity than that of the plating liquid  600  and comprising, for example, a film or a ceramic plate. The high resistance structure  630  has a thickness gradually increasing, beginning at the center, toward the periphery. The electric resistance of the high resistance structure  630  is higher on the periphery than at the center, thus making the influence of the electric resistance of the copper seed layer smaller. As a result, a plated copper film with a more uniform thickness is deposited on the surface of the substrate W. 
       FIG. 35  shows a modification of  FIG. 32 , showing a copper plating device  620  which includes an insulator  632  having a plurality of through-holes  632   c  of the same size (internal diameter) at arbitrary positions thereof to distribute the through-holes  632   c  of the same size arbitrarily over the plane of the substrate W. By so doing, the insulator  632  can be made easily. 
       FIG. 36  shows a copper plating device  620  which includes an anode plate  606  bulges upward like a mountain at the center compared with the peripheral edge. Thus, the distance of the center of the anode plate  606  from the substrate W is shorter than the distance of the periphery of the anode plate  606  from the substrate W. As a result, a greater plating electric current than in a normal situation flows through the center of the substrate, thereby depositing a plated copper film of a uniform thickness on the substrate. 
       FIG. 37  shows a modification of  FIG. 36 , showing a copper plating device  630  which includes a flat plate-shaped anode plate  606  curved upward in the form of a spherical crust, whereby the distance of the center of the anode plate  606  from the substrate W is shorter than the distance of the periphery of the anode plate  606  from the substrate W. 
     A so-called black film is formed on the surface of the anode plate (anode)  606 . If a peeled piece of the black film approaches and adheres to the treated surface (surface) of the substrate W, it adversely affects the plated copper film. Thus, it is preferred to surround the anode plate  606  with a filter film  638 , as shown in  FIG. 38 , and prevent the outflow of the peeled piece of the black film by use of the filter film  638 . In this example, provision of the filter film  636  is applied to the example shown in  FIG. 30 , but needless to say, can be similarly applied to other examples. 
       FIG. 39  shows a copper plating device  630  which includes the same insulator  632  having the central hole  632   a  shown in  FIG. 29 . This insulator  632  is connected to an upwardly and downwardly moving rod  642  of an upwardly and downwardly moving mechanism  640 , and the relative position of the insulator  632  relative to the positive electrode  606  and the substrate W is changed in accordance with driving of the upwardly and downwardly moving mechanism  640 . According to this contrivance, the electric field between the anode plate  606  and the substrate W can be adjusted via the insulator  632 . 
       FIG. 40  shows a copper plating device  630  which includes a disk-shaped insulator (virtual anode)  644  having a plurality of through-holes  644   a , and a similarly disk-shaped insulator (virtual anode)  646  having a plurality of through-holes  646   a  and stacked rotatably on the insulator  644 . One of the insulators  646 , is rotated via a rotating rod  650  of a rotating mechanism  648  to change the phases of both insulators  644  and  646 . The number of the through-holes  644   a  and  646   a  of the insulators  644  and  646  communicating with each other is changed in accordance with the change in the phases. According to this design, the electric field between the anode plate  606  and the substrate W can be adjusted by adjusting the angle of rotation of the insulator  646 . 
       FIGS. 41 to 46  show the CMP device (polishing device)  624  having a polishing amount adjusting mechanism. 
       FIGS. 41 and 42  show a CMP device  624  which includes a polishing belt  652  composed of belt-shaped polishing cloth or a cloth having abrasive grains fixed thereto. The polishing belt  652  is looped between a pair of rollers  654  and  654 , with its polishing surface directed outward. A substrate W attracted and held by a polishing head  656  is pressed against the polishing belt  652  which is traveling, with the substrate W being rotated. The polishing surface of the polishing belt  652  is supplied with an abrasive liquid or pure water (containing a pH adjustor) from an abrasive liquid supply nozzle  658 . 
     A press device  668  is disposed below the polishing head  656  and at a position at which the press device  668  and the polishing head  656  sandwich the polishing belt  652  running upper side. The press device  668  comprises a central disk  664  and an annular plate  666  surrounding the central disk  664 . The central disk  664  and the annular plate  666  are housed in a housing  660  and can be raised and lowered individually via actuators  662   a ,  662   b . Because of this press device  668 , the upper surface of the annular plate  666 , for example, can be caused to protrude above the upper surface of the central disk  664 , thereby making it possible to make the amount of polishing of the peripheral edge portion of the substrate W larger than that of the central portion of the substrate W. 
     In this case, the polishing head  656  may be one exerting a single pressure on the entire surface of the substrate, or may be a top ring  300  as shown in  FIGS. 9 to 16 . 
     As shown in  FIGS. 43A and 43B , Teflon 670 (trademark) may be bonded to the upper surfaces of the central disk  664  and the annular plate  666 , whereby friction occurring between the polishing belt  652  and the central disk  664 , and the polishing belt  652  and the annular plate  666  can be diminished. 
     In polishing copper, the use of abrasive grains fixed to the belt is preferred to the use of the polishing cloth as the polishing surface supplied with an abrasive liquid, because dishing can be minimized for copper which is a soft metal. 
       FIGS. 44 to 46  show another example of the CMP device  624 . In the CMP device  624 , a rotary table  676  of a larger diameter than that of a substrate W is coupled to the upper end of a rotating shaft  674  which rotates in accordance with the rotation of a motor  672 . The substrate W is held to the upper surface of the rotary table  676 , with its device-formed face (surface) directed upward, and is rotated in this state. A polishing tool  678  having abrasive grains or an abrasive cloth fixed thereto and having a diameter smaller than the radius of the substrate W is pressed, while being rotated, against the substrate W, and simultaneously an abrasive liquid or pure water is supplied from an abrasive liquid supply nozzle  680  to the surface of the substrate W to polish the substrate W. The film thickness of the plated copper film after polished is measured by a film thickness sensor  682  at the position located beside the polishing tool  678 . 
     The polishing tool  678  is moved in the diametrical direction of the substrate to perform polishing of the entire surface of the substrate. If the plated copper film is thicker on the periphery of the substrate than at the center of the substrate, the radially moving speed of the polishing tool  678  on the periphery of the substrate should be slowed. Moreover, the film thickness sensor  682 , such as an optical sensor, is mounted in order to control the radially moving speed of the polishing tool  678  while measuring the plated copper film thickness at the annular zone of the substrate being polished. By so doing, the plated copper film of a film thickness different between the center and periphery of the substrate can be flattened. In this case, as shown in  FIG. 46 , the position of the film thickness sensor  682  is preferably downstream from the polishing tool  678  in the rotating direction of the substrate, and position of the supply of the abrasive liquid is desirably upstream from the polishing tool  678  in the rotating direction of the substrate. 
     Some or all of the copper plating device  620  having the film thickness adjusting mechanism for the plated copper film at the center and the periphery of the substrate W, the film thickness distribution measuring device  622 , and the CMP device (polishing device)  624  capable of adjusting the amount of polishing at the center and the periphery of the substrate W may be integrated into a single apparatus. 
     The following embodiments show examples of the integrated apparatus. A seed layer forming chamber may be added to an integrated apparatus as shown in  FIG. 47 . Formation of the seed layer can be performed using an ordinary CVD device or sputtering device, or by electroless-plating. A barrier layer forming device may be included in the integral type. 
       FIG. 47  is a view showing a plan configuration of a semiconductor substrate processing apparatus. The present semiconductor substrate processing apparatus comprises a loading/unloading portion  701 , a copper plating device  620 , a first robot  703 , a third cleaner  704 , an inverting machine  705 , an inverting machine  706 , a second cleaner  707 , a second robot  708 , a first cleaner  709 , a first CMP device  624   a , and a second CMP device  624   b . A film thickness distribution measuring device  622  for measuring the film thicknesses of the plated film before and after plating, and a film thickness distribution measuring device  626  for measuring the film thickness of the dry plated copper film on the semiconductor substrate W after polishing are disposed near the first robot  703 . 
     The film thickness distribution measuring devices  622 ,  626 , especially, the film thickness distribution measuring device  626  for measuring the film thickness distribution after polishing, may be provided on the hand of the first robot  703 . The film thickness distribution measuring device  622 , although not illustrated, may be provided at the semiconductor substrate carry-in/carry-out port of the copper plating device  620  to measure the film thickness of the semiconductor substrate W carried in, and the film thickness of the semiconductor substrate W carried out. 
     The first CMP device  624   a  comprises a polishing table  710   a , a top ring  710   b , a top ring head  710   c , a film thickness distribution measuring device  626   a , and a pusher  710   e . The second CMP device  624   b  comprises a polishing table  711   a , a top ring  711   b , a top ring head  711   c , a film thickness distribution measuring device  626   b , and a pusher  711   e.    
     A box housing a substrate cassette  22  accommodating semiconductor substrates W having a contact hole  3  and a trench  4  for an interconnection, and a seed layer  7  formed thereon is placed on the stage of the loading/unloading portion  701 . The box is opened by a box opening/closing mechanism, and then the semiconductor substrate W is withdrawn from the substrate cassette  22  by the first robot  703 , and carried into the copper plating device  620  for forming a copper film  6 . Before formation of the copper film  6 , the film thickness of the seed layer  7  is measured with the film thickness distribution measuring device  626 . Formation of the copper film  6  is carried out by copper plating device  620 . After formation of the copper film  6 , the substrate is rinsed or cleaned by the copper plating device  620 . If time permits, the substrate may be dried. 
     When the semiconductor substrate W is withdrawn from the copper plating device  620  by the first robot  703 , the film thickness distribution of the copper film (plated copper film)  6  is measured with the film thickness distribution measuring device  626 . The measuring method is the same as for the seed layer  7 . The results of the measurement are recorded in a recorder (not shown) as recorded data on the semiconductor substrate, and are also used for judgement of an abnormality of the copper plating device  620 . After the film thickness is measured, the first robot  703  transfers the semiconductor substrate W to the inverting machine  705 , which turns the semiconductor substrate W upside down (the surface where the copper film  6  has been formed is directed downward). 
     The second robot  708  picks up the semiconductor substrate W on the inverting machine  705 , and places the semiconductor substrate W on the pusher  710   e  of the CMP device  624   a . The top ring  710   b  attracts the semiconductor substrate W on the pusher  710   e , and presses the surface, where the copper film  6  has been formed, of the semiconductor substrate W against the polishing surface of the polishing table  710   a  to carry out polishing. 
     Silica, alumina or ceria is used as abrasive grains for polishing of the copper film  6 , and a material for oxidizing copper mainly with an acidic material, such as hydrogen peroxide, is used as an oxidizing agent. An adjusted temperature fluid piping for passing a liquid adjusted to a predetermined temperature is connected to the interior of the polishing table  710   a  in order to maintain the temperature of the polishing table  710   a  at a predetermined value. In order that the temperature of a slurry containing the abrasive grains and oxidizing agent is also maintained at a predetermined value, a temperature adjustor is provided in a slurry nozzle for ejecting the slurry. The temperature of water or the like for dressing is also adjusted, although this is not shown. In this manner, the temperature of the polishing table  710   a , the temperature of the slurry, and the temperature of water or the like for dressing are kept at predetermined values, whereby the chemical reaction rate is kept constant. As the polishing table  710   a , in particular, alumina or ceramic, such as SiC, with high thermal conductivity is used. 
     To detect the end point of polishing, there is performed film thickness measurement of the copper film  6  by use of an eddy current type film thickness measuring machine or an optical film thickness measuring machine provided on the polishing table  710   a ; or surface detection of the barrier layer  5 . The time when the film thickness of the copper film  6  is found to be zero or when the surface of the barrier layer  5  is detected is taken as the end point of polishing. 
     After polishing of the copper film  6  is completed, the top ring  710   b  returns the semiconductor substrate W onto the pusher  710   e . The second robot  708  takes up the semiconductor substrate W, and puts it into the first cleaner  709 . At this time, a chemical liquid may be jetted at the face side and back side of the semiconductor substrate Won the pusher  710   e  to remove particles or make particles difficult to adhere. 
     In the first cleaner  709 , the face side and back side of the semiconductor substrate W are scrub cleaned with, for example, a PVA sponge roll. In the first cleaner  709 , cleaning fluid ejected from the nozzle is mainly pure water, but may be one mixed with a surfactant and/or a chelating agent, and then pH adjusted in harmony with the zeta potential of copper oxide. Also, an ultrasonic vibratory element may be provided on the nozzle to apply ultrasonic vibrations to the cleaning fluid ejected. During scrub cleaning, the semiconductor substrate W is gripped by a rotating roller and rotated in a horizontal plane. 
     After completion of cleaning, the second robot  708  transfers the semiconductor substrate W to the second CMP device  624   b , and places the semiconductor substrate Won the pusher  711   e . The top ring  711   b  attracts the semiconductor substrate W on the pusher  711   e , and presses the surface, where the barrier layer  5  has been formed, of the semiconductor substrate W against the polishing surface of the polishing table  711   a  to carry out polishing. The configurations of the polishing table  711   a  and top ring  711   b  are the same as those of the polishing table  710   a  and top ring  710   b.    
     The polishing surface on the top of the polishing table  711   a  is composed of a polyurethane foam such as IC1000, or the one having abrasive grains fixed thereto or impregnated with abrasive grains. Polishing is performed by the relative movement of the polishing surface and the semiconductor substrate W. At this time, silica, alumina or ceria is used for abrasive grains or slurry. A chemical liquid is adjusted according to the type of the film to be polished. 
     After polishing is completed, the top ring  711   b  transfers the semiconductor substrate W to the pusher  711   e . The second robot  708  takes up the semiconductor substrate W on the pusher  711   e . At this time, a chemical liquid may be jetted at the face side and back side of the semiconductor substrate W on the pusher  711   e  to remove particles or make particles difficult to adhere. 
     The second robot  708  transfers the semiconductor substrate W to the second cleaner  707  for cleaning. The configuration of the second cleaner  707  is also the same as the configuration of the first cleaner  709 . Pure water is mainly used as a cleaning fluid for removal of particles, and a surfactant, a chelating agent, or a pH adjusting agent may be used. The surface of the semiconductor substrate W is scrub cleaned with a PVA sponge roll. A strong chemical liquid, such as DHF, is ejected from the nozzle toward the back side of the semiconductor substrate W to etch diffused copper. Without the problem of diffusion, the back side of the semiconductor substrate W is scrub cleaned with a PVA sponge roll using the same chemical liquid as for the surface of the semiconductor substrate W. 
     Upon completion of the above cleaning, the second robot  708  takes up the semiconductor substrate W, and transfers it to the inverting machine  706 , which turns the semiconductor substrate W upside down. The thus inverted semiconductor substrate W is picked up by the first robot  703  and placed in the third cleaner  704 . The third cleaner  704  jets megasonic water, which has been excited by ultrasonic vibrations, at the surface of the semiconductor substrate W to clean the semiconductor substrate W. At this time, pure water, a surfactant, a chelating agent, or a pH adjusted agent may be added, and the surface of the semiconductor substrate W may be cleaned with a publicly known pencil type sponge. Then, the semiconductor substrate W is dried by spin drying. 
       FIG. 48  is a view showing the plan layout of another example of the substrate processing apparatus. This substrate processing apparatus comprises a barrier layer forming unit  811 , a seed layer forming unit  812 , a plating film forming unit (plating device)  813 , an annealing unit  814 , a first cleaning unit  815 , a bevel/back side cleaning unit  816 , a cap-plating unit  817 , a second cleaning unit  818 , a first aligner and film thickness measuring instrument  841 , a second aligner and film thickness measuring instrument  842 , a first substrate inverting machine  843 , a second substrate inverting machine  844 , a substrate temporary placing table  845 , a third film thickness measuring instrument  846 , a loading/unloading portion  820 , a first CMP device  821 , a second CMP device  822 , a first robot  831 , a second robot  832 , a third robot  833 , and a fourth robot  834 . 
     In this example, an electroless copper plating device can be used as the barrier layer forming unit  811 , an electroless copper plating device can be used as the seed layer forming unit  812 , and an electric plating device can be used as the plating film forming unit  813 . 
       FIGS. 49A to 49E  show an example in which the film thickness distribution is adjusted more uniformly by two copper plating devices having different film thickness distribution characteristics. As shown in  FIG. 49B , the first-stage plating device  620   a  is one designed to deposit a plated copper film P 1  having film thickness distribution characteristics with the film thickness increasing on the periphery. As shown in  FIG. 49C , the second-stage plating device  620   b  is one designed to deposit a plated copper film P 2  having film thickness distribution characteristics with the film thickness increasing at the center. 
     These two copper plating devices  620   a  and  620   b  are arranged in series to perform copper plating of the substrate, thereby depositing the plated copper film P 1  as shown in  FIG. 49D , and then depositing the plated copper film P 2  thereon as shown in  FIG. 49E . By adjusting the periods of time for these plating steps, a plated copper film with a more uniform film thickness distribution can be obtained. This method can change the thickness distribution at the center and periphery of the substrate even during plating. Since the method needs only changes in the plating time and does not require a mechanical adjusting mechanism, it can adjust the plated copper film thickness distribution in situ. 
     If the film thickness of the plated copper film after the second-stage plating is larger at the center, an adjustment is made to increase the plating time or the plating electric current for the first-stage plating, or to decrease the plating time or the plating electric current for the second-stage plating. This adjustment makes it possible to decrease variations in the film thickness of the plated copper film at the center and periphery of the substrate after the second-stage plating. 
     It goes without saying that the first-stage plating device may be one designed to deposit a plated copper film having film thickness distribution characteristics with the film thickness increasing at the center, and the second-stage plating device may be one designed to deposit a plated copper film having film thickness distribution characteristics with the film thickness increasing on the periphery. 
     As shown in  FIG. 50 , it is acceptable to perform the first-stage plating by the first-stage plating device  620   a , measure the film thickness distribution of the plated copper film by a film thickness distribution measuring device  622   a , and adjust the plating period of the second-stage plating device  620   b  on the basis of the results of measurement. In this case, it is possible to further decrease variations in the film thickness of the plated copper film at the center and periphery of the substrate after the second-stage plating. 
     In this manner, the combined use of the plating device capable of adjusting the film thickness of the plated copper film at the center and periphery of the substrate, and the film thickness distribution measuring device for the center and periphery of the substrate enables an adjustment to be made so as to decrease variations in the film thickness of the plated copper film at the center and periphery of the substrate after plating. This can be achieved by a simple adjustment, as well as automation by a control device using common techniques such as feedback control and/or feed forward control. Furthermore, it is possible not only to make an adjustment so as to decrease variations in the film thickness of the plated copper film at the center and periphery of the substrate, but also to plate a plated copper film having a distribution of the film thickness of the plated copper film at the center and periphery of the substrate, the distribution adapted to the polishing properties of a CMP device for the periphery and center of the substrate. For example, when the plating device is combined with a polishing device which polishes more at the center than on the periphery of the substrate, it is recommendable to plate a plated copper film thicker at the center than on the periphery of the substrate. 
     To polish the plated copper film, the CMP device used here, which can adjust the pressures on the center and the periphery of the substrate independently, may be an ordinary CMP device which presses a substrate held by a rotating head against a polishing cloth attached to an ordinary rotary table, and polishes the substrate with an abrasive liquid supplied to the polishing cloth. However, a fixed abrasive grain type polishing device having abrasive grains fixed thereto is desired in order to prevent dishing. The desired head is one which presses the substrate by a fluid pressure. When the fixed abrasive grain type polishing device is used, scratches due to polishing may occur on the surface of the plated copper film. To remove them, it is desirable to polish the substrate with the fixed abrasive grains at the first stage, and carry out ordinary polishing with a polishing cloth and an abrasive liquid at the second stage, thereby removing the scratches. 
     The plating device having the film thickness distribution adjusting mechanism for the plated copper film at the center and periphery of the substrate, the film thickness distribution measuring device, and the CMP device capable of adjusting the polishing amount for the center and periphery of the substrate may be housed separately in the clean room. In this case, in order to prevent oxidation of the surface of the plated copper film, it is desirable to use the substrate transport box such as SMIF or HOOP mentioned in the previous embodiments, and further use a transport device adapted to circulate gases inside the substrate transport box, and isolate the gases in the atmosphere around the substrate from the clean room by a particle filter placed inside the substrate transport box, or this particle filter combined with a chemical filter and further a dehumidifier, thereby controlling the amount of particles, the amount of oxygen, or the amount of steam. Moreover, the atmosphere inside each device is desirably isolated from the clean room by a partition or the like, with the amount of oxygen or steam inside the device being controlled. 
     Further, as shown in  FIG. 51 , the electric resistance of the copper seed layer  7  formed on the surface of the substrate may be measured before copper plating, and based on the results, the film thickness distribution adjusting mechanism of the copper plating device for the center and periphery of the plated copper film may be adjusted. This measurement of the electric resistance of the copper seed layer may be made using a device other than the plating device. However, it is desired to measure the resistance between the cathode and the copper seed layer in the actual plating state, so that the electric resistance of the copper seed layer should be measured using the cathode contacts of the plating device. 
       FIGS. 52 to 63  show examples of an electric terminal members serving concurrently as copper seed layer resistance measuring terminals and a cathode. As shown in  FIGS. 52 and 53 , a semiconductor substrate W is placed on a substrate placing stand  900  composed of an isolator, with the copper seed layer formed surface of the substrate being directed downward. On a surface of the substrate placing stand  900  receiving the substrate W, a plurality of electric terminals  902  are arranged with a predetermined pitch along the circumferential direction. When concurrently used as a cathode, the electric terminals  902 , at least, need to be prevented from contacting with a plating liquid. For this purpose, sealing members  904 ,  906  are arranged on both sides (outside and inside) of the electric terminals  902 , and the sealing member  609  is pressed by a seal press  908 , whereby a sealing mechanism is constituted in this example. Only the inner sealing material  906  for the electric terminal  902  may be provided. 
     The electric terminal  902  is formed in a rectangular shape in this embodiment, but may be in the form of a knife edge making linear contact with the copper seed layer, as shown in  FIG. 54A . Also, the electric terminal  902  may be pinnacle-shaped so as to make point contact with the copper seed layer, although this is not shown. The point contact can decrease electric resistance between the electric terminal and the copper seed layer. 
     As shown in  FIG. 54B , moreover, it is desired to provide a structure in which a spring  910  is disposed beneath each electric terminal  902 , whereby each electric terminal  902  is urged upward by the elastic force of the spring  910  and independently pressed against the copper seed layer with a constant force. In addition, as shown in  FIG. 54C , there may be a structure in which the electric terminal  902  is composed of a bent metallic plate and can be pressed, by itself, against the copper seed layer. At least the surface of the electric terminal  902  is desirably made of metal or platinum in order to decrease contact resistance between the electric terminal and the copper seed layer. 
     The substrate placing stand  900  desirably has a centering mechanism in order that the electric terminal  902  does not disengage from the substrate W. Examples of the centering structure are one in which an inner circumferential surface of the substrate placing stand  900  brought in contact with the substrate W is a tapered surface  900   a , as shown in  FIG. 55A , and one in which a metal plate is bent so as to have a centering mechanism for the substrate, thereby constituting an electric terminal  902 , and a centering mechanism for the substrate is imparted to the electric terminal  902  itself, as shown in  FIG. 55B . 
     In these examples, the device for measuring the resistance of the copper seed layer measures the resistance, with the copper seed layer facing downward. Needless to say, however, the resistance may be measured, with the copper seed layer facing upward. 
     Next, the method of measuring the electric resistance of the copper seed layer will be described. 
     To measure the resistance of the copper seed layer, it is recommendable to apply a direct current voltage between the two electric terminals  902  and  902  located opposite to each other with respect to the center of the substrate W, and measure an electric current flowing between the two electric terminals  902  and  902 . By performing this measurement between the electric terminals  902  and  902  sandwiching the enter of the substrate W, as shown in  FIG. 56 , a plurality of data (four data in this example, because eight of the electric terminals are present) can be obtained. Since errors exist in the measurements of electric resistance, the resistance value of the entire substrate can be found by various methods, such as calculating the arithmetic mean of the data, calculating the root mean square, and averaging the measured data with the exception of the maximum value and the minimum value. 
     The thus obtained measured value of the electric resistance of the seed layer is compared with the standard value of the electric resistance of the seed layer. If the measured value is greater than the standard value, there is a possibility that the plated copper film will be thicker on the periphery of the substrate than at the center of the substrate. Thus, the substrate center/periphery film thickness adjusting mechanism of the copper plating device is adjusted so that the plated copper film will be flat. 
     Furthermore, as shown in  FIG. 57 , two adjacent electric terminals  902  and  902  may be used as one electrode to measure resistance between these two adjacent electric terminals and the corresponding two adjacent electric terminals located on the opposite side relative to the center of the substrate. In this case, as shown in  FIGS. 58A and 58B , combinations of the electric terminals  902  may be changed sequentially using the adjacent electric terminals  902  to make measurements. 
     In addition, as shown in  FIGS. 59A to 59C , the electric resistances between the arbitrary electric terminals  902  and  902  arranged around the edge of the substrate W may be measured (for example, the number of the electric terminals in this example is eight, so that there are at most  720  measurements), and the corresponding simultaneous equations may be solved, whereby the planar distribution of the electric resistance of the copper seed layer can be approximatively obtained. The use of this method approximatively gives the electric resistances R 10  to R 80  between the center of the substrate and the surroundings of the substrate edge as shown in  FIG. 61 . 
       FIGS. 60 and 61  show other example of measuring the distribution of the electric resistance of the copper seed layer. This example includes an electrode terminal arm  914  having a central electric terminal  912 , brought into contact with the copper seed layer at the center of the substrate W. In this example, the electrode terminal arm  914  is of a movable type, and moves to the center of the substrate w only when measuring the electric resistance, and retreats when plating is performed. 
     In this example, a direct current voltage is sequentially applied between the central electric terminal  912  at the center of the substrate and the respective electric terminals  902  arranged around the edge of the substrate. The values of electric current flowing at this time are measured, thereby making it possible to find the electric resistances R 10 , R 20  . . . R 80  of the copper seed layer between the central electric terminal  912  disposed at the center of the substrate and the respective electric terminals  902  arranged around the edge of the substrate as shown in  FIG. 61 . 
     Based on the thus found electric resistance distribution (e.g., R 10  to R 80 ) of the copper seed layer, voltages to be applied to the respective electric terminals of the cathode at the time of copper plating are adjusted and controlled independently, thus making it possible to adjust not only the distribution of the film thickness of the plated copper film in the radial direction of the substrate, but also the distribution of the film thickness of the plated copper film in the circumferential direction of the substrate. These adjustments may be made automatically by use of an ordinary control device adopting feed forward sequence control. 
       FIG. 65  is a plan view of an example of a substrate plating apparatus. The substrate plating apparatus shown in  FIG. 65  comprises a loading/unloading area  1520  for housing substrate cassettes which accommodate semiconductor substrates, a processing area  1530  for processing semiconductor substrates, and a cleaning/drying area  1540  for cleaning/drying plated semiconductor substrates. The cleaning/drying area  1540  is positioned between the loading/unloading area  1520 , and the processing area  1530 . A partition  1521  is disposed between the loading/unloading area  1520 , and the cleaning/drying area  1540 . And a partition  1523  is disposed between the cleaning/drying area  1540 , and the processing area  1530 . 
     The partition  1521  has a passage (not shown) defined therein for transferring semiconductor substrates therethrough between the loading/unloading area  1520 , and the cleaning/drying area  1540 , and supports a shutter  1522  for opening/closing the passage. The partition  1523  has a passage (not shown) defined therein for transferring semiconductor substrates therethrough between the cleaning/drying area  1540 , and the processing area  1530 , and supports a shutter  1524  for opening/closing the passage. The cleaning/drying area  1540  and the processing area  1530  can independently be supplied with and discharge air. 
     The substrate plating apparatus shown in  FIG. 65  is placed in a clean room, which accommodates semiconductor fabrication facilities. The pressures in the loading/unloading area  1520 , the processing area  1530 , and the cleaning/drying area  1540  are selected as follows: 
     The pressure in the loading/unloading area  1520 &gt;the pressure in the cleaning/drying area  1540 &gt;the pressure in the processing area  1530 . 
     The pressure in the loading/unloading area  1520  is lower than the pressure in the clean room. Therefore, air does not flow from the processing area  1530  into the cleaning/drying area  1540 , and air does not flow from the cleaning/drying area  1540  into the loading/unloading area  1520 . Furthermore, air does not flow from the loading/unloading area  1520  into the clean room. 
     The loading/unloading area  1520  houses a loading unit  1520   a  and an unloading unit  1520   b , each accommodating a substrate cassette for storing semiconductor substrates. The cleaning/drying area  1540  houses two water cleaning units  1541  for cleaning plated semiconductor substrates with water, and two drying units  1542  for drying plated semiconductor substrates. Each of the water cleaning units  1541  may comprise a pencil-shaped cleaner with a sponge layer mounted on a front end thereof or a roller with a sponge layer mounted on an outer circumferential surface thereof. Each of the drying units  1542  may comprise a drier for spinning a semiconductor substrate at a high speed to dehydrate and dry. The cleaning/drying area  1540  also has a transfer unit (transfer robot)  1543  for transferring semiconductor substrates. 
     The processing area  1530  houses a plurality of pretreatment chambers  1531  for pretreating semiconductor substrates prior to being plated, and a plurality of plating chambers  1532  for plating semiconductor substrates with copper. The processing area  1530  also has a transfer unit (transfer robot)  1543  for transferring semiconductor substrates. 
       FIG. 66  shows in side elevation air flows in the substrate plating apparatus. As shown in  FIG. 66 , fresh air is introduced from the exterior through a duct  1546  and forced through high-performance filters  1544  by fans from a ceiling  1540   a  into the cleaning/drying area  1540  as downward clean air flows around the water cleaning units  1541  and the drying units  1542 . Most of the supplied clean air is returned from a floor  1540   b  through a circulation duct  1545  to the ceiling  1540   a , from which the clean air is forced again through the filters  1544  by the fans into the cleaning/drying area  1540 . Part of the clean air is discharged from the wafer cleaning units  1541  and the drying units  1542  through a duct  1552  out of the cleaning/drying area  1540 . 
     In the processing area  1530  which accommodates the pretreatment chambers  1531  and the plating chambers  1532 , particles are not allowed to be applied to the surfaces of semiconductor substrates even though the processing area  1530  is a wet zone. To prevent particles from being applied to semiconductor substrates, downward clean air flows around the pretreatment chambers  1531  and the plating chambers  1532 . Fresh air is introduced from the exterior through a duct  1539  and forced through high-performance filters  1533  by fans from a ceiling  1530   a  into the processing area  1530 . 
     If the entire amount of clean air as downward clean air flows introduced into the processing area  1530  were always supplied from the exterior, then a large amount of air would be required to be introduced into and discharged from the processing area  1530  at all times. According to this embodiment, air is discharged from the processing area  1530  through a duct  1553  at a rate sufficient enough to keep the pressure in the processing area  530  lower than the pressure in the cleaning/drying area  1540 , and most of the downward clean air introduced into the processing area  1530  is circulated through circulation ducts  1534 ,  1535 . The circulation duct  1534  extends from the cleaning/drying area  1540  and is connected to the filters  1533  over the ceiling  1530   a . The circulation duct  1535  is disposed in the cleaning/drying area  1540  and connected to the pipe  1534  in the cleaning/drying area  1540 . 
     The circulating air that has passed through the processing area  1530  contains a chemical mist and gases from solution bathes. The chemical mist and gases are removed from the circulating air by a scrubber  1536  and mist separators  1537 ,  1538  which are disposed in the pipe  1534  that is connected to the pipe  1535 . The air which circulates from the cleaning/drying area  1540  through the scrubber  1536  and the mist separators  1537 ,  1538  back into the circulation duct  1534  over the ceiling  1530   a  is free of any chemical mist and gases. The clean air is then forced through the filters  1533  by the fans to circulate back into the processing area  1530 . 
     Part of the air is discharged from the processing area  1530  through the duct  1553  connected to a floor  1530   b  of the processing area  1530 . Air containing a chemical mist and gases is also discharged from the processing area  1530 , through the duct  1553 . An amount of fresh air which is commensurate with the amount of air discharged through the duct  1553  is supplied from the duct  1539  into the plating chamber  1530  under the negative pressure developed therein with respect to the pressure in the clean room. 
     As described above, the pressure in the loading/unloading area  1520  is higher than the pressure in the cleaning/drying area  1540  which is higher than the pressure in the processing area  1530 . When the shutters  1522 ,  1524  (see  FIG. 65 ) are opened, therefore, air flows successively through the loading/unloading area  1520 , the cleaning/drying area  1540 , and the processing area  1530 , as shown in  FIG. 67 . Air discharged from the cleaning/drying area  1540  and the processing area  1530  flows through the ducts  1552 ,  1553  into a common duct  1554  (see  FIG. 68 ) which extends out of the clean room. 
       FIG. 68  shows in perspective the substrate plating apparatus shown in  FIG. 65 , which is placed in the clean room. The loading/unloading area  1520  includes a side wall which has a cassette transfer port  1555  defined therein and a control panel  1556 , and which is exposed to a working zone  1558  that is compartmented in the clean room by a partition wall  1557 . The partition wall  1557  also compartments a utility zone  1559  in the clean room in which the substrate plating apparatus is installed. Other sidewalls of the substrate plating apparatus are exposed to the utility zone  1559  whose air cleanness is lower than the air cleanness in the working zone  1558 . 
     As described above, the cleaning/drying area  1540  is disposed between the loading/unloading area  1520 , and the processing area  1530 . The partition  1521  is disposed between the loading/unloading area  1520 , and the cleaning/drying area  1540 . The partition  1523  is disposed between the cleaning/drying area  1540 , and the processing area  1530 . A dry semiconductor substrate is loaded from the working zone  1558  through the cassette transfer port  1555  into the substrate plating apparatus, and then plated in the substrate plating apparatus. The plated semiconductor substrate is cleaned and dried, and then unloaded from the substrate plating apparatus through the cassette transfer port  1555  into the working zone  1558 . Consequently, no particles and mist are applied to the surface of the semiconductor substrate, and the working zone  1558  which has higher air cleanness than the utility zone  1557  is prevented from being contaminated by particles, chemical mists, and cleaning solution mists. 
     In the embodiment shown in  FIGS. 65 and 66 , the substrate plating apparatus has the loading/unloading area  1520 , the cleaning/drying area  1540 , and the processing area  1530 . However, an area accommodating a chemical mechanical polishing unit may be disposed in or adjacent to the processing area  1530 , and the cleaning/drying area  1540  may be disposed in the processing area  1530  or between the area accommodating the chemical mechanical polishing unit and the loading/unloading area  1520 . Any of various other suitable area and unit layouts may be employed insofar as a dry semiconductor substrate can be loaded into the substrate plating apparatus, and a plated semiconductor substrate can be cleaned and dried, and thereafter unloaded from the substrate plating apparatus. 
     In the embodiment described above, the present invention is applied to the substrate plating apparatus for plating a semiconductor substrate. However, the principles of the present invention are also applicable to a substrate plating apparatus for plating a substrate other than a semiconductor substrate. Furthermore, a region on a substrate plated by the substrate plating apparatus is not limited to an interconnection region on the substrate. The substrate plating apparatus may be used to plate substrates with a metal other than copper. 
       FIG. 69  is a plan view of another example of a substrate plating apparatus. The substrate plating apparatus shown in  FIG. 69  comprises a loading unit  1601  for loading a semiconductor substrate, a copper plating chamber  1602  for plating a semiconductor substrate with copper, a pair of water cleaning chambers  1603 ,  1604  for cleaning a semiconductor substrate with water, a chemical mechanical polishing unit  1605  for chemically and mechanically polishing a semiconductor substrate, a pair of water cleaning chambers  1606 ,  1607  for cleaning a semiconductor substrate with water, a drying chamber  1608  for drying a semiconductor substrate, and an unloading unit  1609  for unloading a semiconductor substrate with an interconnection film thereon. The substrate plating apparatus also has a wafer transfer mechanism (not shown) for transferring semiconductor substrates to the chambers  1602 ,  1603 ,  1604 , the chemical mechanical polishing unit  1605 , the chambers  1606 ,  1607 ,  1608 , and the unloading unit  1609 . The loading unit  1601 , the chambers  1602 ,  1603 ,  1604 , the chemical mechanical polishing unit  1605 , the chambers  1606 ,  1607 ,  1608 , and the unloading unit  1609  are combined into a single unitary arrangement as apparatus. 
     The substrate plating apparatus operates as follows: The wafer transfer mechanism transfers a semiconductor substrate W on which an interconnection film has not yet been formed from a substrate cassette  1601 - 1  placed in the loading unit  1601  to the copper plating chamber  1602 . In the copper plating chamber  1602 , a plated copper film is formed on a surface of the semiconductor substrate W having an interconnection region composed of an interconnection trench and an interconnection hole (contact hole). 
     After the plated copper film is formed on the semiconductor substrate W in the copper plating chamber  1602 , the semiconductor substrate W is transferred to one of the water cleaning chambers  1603 ,  1604  by the wafer transfer mechanism and cleaned by water in one of the water cleaning chambers  1603 ,  1604 . The cleaned semiconductor substrate W is transferred to the chemical mechanical polishing unit  1605  by the wafer transfer mechanism. The chemical mechanical polishing unit  1605  removes the unwanted plated copper film from the surface of the semiconductor substrate W, leaving a portion of the plated copper film in the interconnection trench and the interconnection hole. A barrier layer made of TiN or the like is formed on the surface of the semiconductor substrate W, including the inner surfaces of the interconnection trench and the interconnection hole, before the plated copper film is deposited. 
     Then, the semiconductor substrate W with the remaining plated copper film is transferred to one of the water cleaning chambers  1606 ,  1607  by the wafer transfer mechanism and cleaned by water in one of the water cleaning chambers  1607 ,  1608 . The cleaned semiconductor substrate W is then dried in the drying chamber  1608 , after which the dried semiconductor substrate W with the remaining plated copper film serving as an interconnection film is placed into a substrate cassette  1609 - 1  in the unloading unit  1609 . 
       FIG. 70  shows a plan view of still another example of a substrate plating apparatus. The substrate plating apparatus shown in  FIG. 70  differs from the substrate plating apparatus shown in  FIG. 69  in that it additionally includes a copper plating chamber  1602 , a water cleaning chamber  1610 , a pretreatment chamber  1611 , a protective layer plating chamber  1612  for forming a protective plated layer on a plated copper film on a semiconductor substrate, water cleaning chamber  1613 ,  1614 , and a chemical mechanical polishing unit  615 . The loading unit  1601 , the chambers  1602 ,  1602 ,  1603 ,  1604 ,  1614 , the chemical mechanical polishing unit  1605 ,  1615 , the chambers  1606 ,  1607 ,  1608 ,  1610 ,  1611 ,  1612 ,  1613 , and the unloading unit  1609  are combined into a single unitary arrangement as an apparatus. 
     The substrate plating apparatus shown in  FIG. 70  operates as follows: A semiconductor substrate W is supplied from the substrate cassette  1601 - 1  placed in the loading unit  1601  successively to one of the copper plating chambers  1602 ,  1602 . In one of the copper plating chamber  1602 ,  1602 , a plated copper film is formed on a surface of a semiconductor substrate W having an interconnection region composed of an interconnection trench and an interconnection hole (contact hole). The two copper plating chambers  1602 ,  1602  are employed to allow the semiconductor substrate W to be plated with a copper film for a long period of time. Specifically, the semiconductor substrate W may be plated with a primary copper film according to electroplating in one of the copper plating chamber  1602 , and then plated with a secondary copper film according to electroless-plating in the other copper plating chamber  1602 . The substrate plating apparatus may have more than two copper plating chambers. 
     The semiconductor substrate W with the plated copper film formed thereon is cleaned by water in one of the water cleaning chambers  1603 ,  1604 . Then, the chemical mechanical polishing unit  1605  removes the unwanted portion of the plated copper film from the surface of the semiconductor substrate W, leaving a portion of the plated copper film in the interconnection trench and the interconnection hole. 
     Thereafter, the semiconductor substrate W with the remaining plated copper film is transferred to the water cleaning chamber  1610 , in which the semiconductor substrate W is cleaned with water. Then, the semiconductor substrate W is transferred to the pretreatment chamber  1611 , and pretreated therein for the deposition of a protective plated layer. The pretreated semiconductor substrate W is transferred to the protective layer-plating chamber  1612 . In the protective layer plating chamber  1612 , a protective plated layer is formed on the plated copper film in the interconnection region on the semiconductor substrate W. For example, the protective plated layer is formed with an alloy of nickel (Ni) and boron (B) by electroless-plating. 
     After semiconductor substrate is cleaned in one of the water cleaning chamber  1613 ,  1614 , an upper portion of the protective plated layer deposited on the plated copper film is polished off to planarize the protective plated layer, in the chemical mechanical polishing unit  1615 , After the protective plated layer is polished, the semiconductor substrate W is cleaned by water in one of the water cleaning chambers  1606 ,  1607 , dried in the drying chamber  1608 , and then transferred to the substrate cassette  1609 - 1  in the unloading unit  1609 . 
       FIG. 71  is a plan view of still another example of a substrate plating apparatus. As shown in  FIG. 71 , the substrate plating apparatus includes a robot  1616  at its center which has a robot arm  1616 - 1 , and also has a copper plating chamber  1602 , a pair of water cleaning chambers  1603 ,  1604 , a chemical mechanical polishing unit  1605 , a pretreatment chamber  1611 , a protective layer plating chamber  1612 , a drying chamber  1608 , and a loading/unloading portion  1617  which are disposed around the robot  1616  and positioned within the reach of the robot arm  1616 - 1 . A loading unit  1601  for loading semiconductor substrates and an unloading unit  1609  for unloading semiconductor substrates is disposed adjacent to the loading/unloading portion  1617 . The robot  1616 , the chambers  1602 ,  1603 ,  1604 , the chemical mechanical polishing unit  1605 , the chambers  1608 ,  1611 ,  1612 , the loading/unloading portion  1617 , the loading unit  1601 , and the unloading unit  1609  are combined into a single unitary arrangement as an apparatus. 
     The substrate plating apparatus shown in  FIG. 71  operates as follows: 
     A semiconductor substrate to be plated is transferred from the loading unit  1601  to the loading/unloading portion  1617 , from which the semiconductor substrate is received by the robot arm  1616 - 1  and transferred thereby to the copper plating chamber  1602 . In the copper plating chamber  1602 , a plated copper film is formed on a surface of the semiconductor substrate which has an interconnection region composed of an interconnection trench and an interconnection hole. The semiconductor substrate with the plated copper film formed thereon is transferred by the robot arm  1616 - 1  to the chemical mechanical polishing unit  1605 . In the chemical mechanical polishing unit  1605 , the plated copper film is removed from the surface of the semiconductor substrate W, leaving a portion of the plated copper film in the interconnection trench and the interconnection hole. 
     The semiconductor substrate is then transferred by the robot arm  1616 - 1  to the water-cleaning chamber  1604 , in which the semiconductor substrate is cleaned by water. Thereafter, the semiconductor substrate is transferred by the robot arm  1616 - 1  to the pretreatment chamber  1611 , in which the semiconductor substrate is pretreated therein for the deposition of a protective plated layer. The pretreated semiconductor substrate is transferred by the robot arm  1616 - 1  to the protective layer plating chamber  1612 . In the protective layer plating chamber  1612 , a protective plated layer is formed on the plated copper film in the interconnection region on the semiconductor substrate W. The semiconductor substrate with the protective plated layer formed thereon is transferred by the robot arm  1616 - 1  to the water cleaning chamber  1604 , in which the semiconductor substrate is cleaned by water. The cleaned semiconductor substrate is transferred by the robot arm  1616 - 1  to the drying chamber  1608 , in which the semiconductor substrate is dried. The dried semiconductor substrate is transferred by the robot arm  1616 - 1  to the loading/unloading portion  1617 , from which the plated semiconductor substrate is transferred to the unloading unit  1609 . 
       FIG. 72  is a view showing the plan constitution of another example of a semiconductor substrate processing apparatus. The semiconductor substrate processing apparatus is of a constitution in which there are provided a loading/unloading section  1701 , a copper plating unit  1702 , a first robot  1703 , a third cleaning machine  1704 , a reversing machine  1705 , a reversing machine  1706 , a second cleaning machine  1707 , a second robot  1708 , a first cleaning machine  1709 , a first polishing apparatus  1710 , and a second polishing apparatus  1711 . A before-plating and after-plating film thickness measuring instrument  1712  for measuring the film thicknesses before and after plating, and a dry state film thickness measuring instrument  1713  for measuring the film thickness of a semiconductor substrate W in a dry state after polishing are placed near the first robot  1703 . 
     The first polishing apparatus (polishing unit)  1710  has a polishing table  1710 - 1 , a top ring  1710 - 2 , a top ring head  1710 - 3 , a film thickness measuring instrument  1710 - 4 , and a pusher  1710 - 5 . The second polishing apparatus (polishing unit)  1711  has a polishing table  1711 - 1 , a top ring  1711 - 2 , a top ring head  1711 - 3 , a film thickness measuring instrument  1711 - 4 , and a pusher  1711 - 5 . 
     A cassette  1701 - 1  accommodating the semiconductor substrates W, in which a via hole and a trench for interconnect are formed, and a seed layer is formed thereon is placed on a loading port of the loading/unloading section  1701 . The first robot  1703  takes out the semiconductor substrate W from the cassette  1701 - 1 , and carries the semiconductor substrate W into the copper plating unit  1702  where a plated Cu film is formed. At this time, the film thickness of the seed layer is measured with the before-plating and after-plating film thickness measuring instrument  1712 . The plated Cu film is formed by carrying out hydrophilic treatment of the face of the semiconductor substrate W, and then Cu plating. After formation of the plated Cu film, rinsing or cleaning of the semiconductor substrate W is carried out in the copper plating unit  1702 . 
     When the semiconductor substrate W is taken out from the copper plating unit  1702  by the first robot  1703 , the film thickness of the plated Cu film is measured with the before-plating and after-plating film thickness measuring instrument  1712 . The results of its measurement are recorded into a recording device (not shown) as record data on the semiconductor substrate, and are used for judgment of an abnormality of the copper plating unit  1702 . After measurement of the film thickness, the first robot  1703  transfers the semiconductor substrate W to the reversing machine  1705 , and the reversing machine  1705  reverses the semiconductor substrate W (the surface on which the plated Cu film has been formed faces downward). The first polishing apparatus  1710  and the second polishing apparatus  1711  perform polishing in a serial mode and a parallel mode. Next, polishing in the serial mode will be described. 
     In the serial mode polishing, a primary polishing is performed by the polishing apparatus  1710 , and a secondary polishing is performed by the polishing apparatus  1711 . The second robot  1708  picks up the semiconductor substrate W on the reversing machine  1705 , and places the semiconductor substrate W on the pusher  1710 - 5  of the polishing apparatus  1710 . The top ring  1710 - 2  attracts the semiconductor substrate W on the pusher  1710 - 5  by suction, and brings the surface of the plated Cu film of the semiconductor substrate W into contact with a polishing surface of the polishing table  1710 - 1  under pressure to perform a primary polishing. With the primary polishing, the plated Cu film is basically polished. The polishing surface of the polishing table  1710 - 1  is composed of foamed polyurethane such as IC1000, or a material having abrasive grains fixed thereto or impregnated therein. Upon relative movements of the polishing surface and the semiconductor substrate W, the plated Cu film is polished. 
     After completion of polishing of the plated Cu film, the semiconductor substrate W is returned onto the pusher  1710 - 5  by the top ring  1710 - 2 . The second robot  1708  picks up the semiconductor substrate W, and introduces it into the first cleaning machine  1709 . At this time, a chemical liquid may be ejected toward the face and backside of the semiconductor substrate W on the pusher  1710 - 5  to remove particles therefrom or cause particles to be difficult to adhere thereto. 
     After completion of cleaning in the first cleaning machine  1709 , the second robot  1708  picks up the semiconductor substrate W, and places the semiconductor substrate W on the pusher  1711 - 5  of the second polishing apparatus  1711 . The top ring  1711 - 2  attracts the semiconductor substrate W on the pusher  1711 - 5  by suction, and brings the surface of the semiconductor substrate W, which has the barrier layer formed thereon, into contact with a polishing surface of the polishing table  1711 - 1  under pressure to perform the secondary polishing. The constitution of the polishing table is the same as the top ring  1711 - 2 . With this secondary polishing, the barrier layer is polished. However, there may be a case in which a Cu film and an oxide film left after the primary polishing are also polished. 
     A polishing surface of the polishing table  1711 - 1  is composed of foamed polyurethane such as IC1000, or a material having abrasive grains fixed thereto or impregnated therein. Upon relative movements of the polishing surface and the semiconductor substrate W, polishing is carried out. At this time, silica, alumina, ceria, on the like is used as abrasive grains or a slurry. A chemical liquid is adjusted depending on the type of the film to be polished. 
     Detection of an end point of the secondary polishing is performed by measuring the film thickness of the barrier layer mainly with the use of the optical film thickness measuring instrument, and detecting the film thickness which has become zero, or the surface of an insulating film comprising SiO 2  shows up. Furthermore, a film thickness measuring instrument with an image processing function is used as the film thickness measuring instrument  1711 - 4  provided near the polishing table  1711 - 1 . By use of this measuring instrument, measurement of the oxide film is made, the results are stored as processing records of the semiconductor substrate W, and used for judging whether the semiconductor substrate W in which secondary polishing has been finished can be transferred to a subsequent step or not. If the end point of the secondary polishing is not reached, repolishing is performed. If over-polishing has been performed beyond a prescribed value due to any abnormality, then the semiconductor substrate processing apparatus is stopped to avoid next polishing so that defective products will not increase. 
     After completion of the secondary polishing, the semiconductor substrate W is moved to the pusher  1711 - 5  by the top ring  1711 - 2 . The second robot  1708  picks up the semiconductor substrate W on the pusher  1711 - 5 . At this time, a chemical liquid may be ejected toward the face and backside of the semiconductor substrate W on the pusher  1711 - 5  to remove particles therefrom or cause particles to be difficult to adhere thereto. 
     The second robot  1708  carries the semiconductor substrate W into the second cleaning machine  1707  where cleaning of the semiconductor substrate W is performed. The constitution of the second cleaning machine  1707  is also the same as the constitution of the first cleaning machine  1709 . The face of the semiconductor substrate W is scrubbed with the PVA sponge rolls using a cleaning liquid comprising pure water to which a surface active agent, a chelating agent, or a pH regulating agent is added. A strong chemical liquid such as DHF is ejected from a nozzle toward the backside of the semiconductor substrate W to perform etching of the diffused Cu thereon. If there is no problem of diffusion, scrubbing cleaning is performed with the PVA sponge rolls using the same chemical liquid as that used for the face. 
     After completion of the above cleaning, the second robot  1708  picks up the semiconductor substrate W and transfers it to the reversing machine  1706 , and the reversing machine  1706  reverses the semiconductor substrate W. The semiconductor substrate W which has been reversed is picked up by the first robot  1703 , and transferred to the third cleaning machine  1704 . In the third cleaning machine  1704 , megasonic water excited by ultrasonic vibrations is ejected toward the face of the semiconductor substrate W to clean the semiconductor substrate W. At this time, the face of the semiconductor substrate W may be cleaned with a known pencil type sponge using a cleaning liquid comprising pure water to which a surface active agent, a chelating agent, or a pH regulating agent is added. Thereafter, the semiconductor substrate w is dried by spin-drying. 
     As described above, if the film thickness has been measured with the film thickness measuring instrument  1711 - 4  provided near the polishing table  1711 - 1 , then the semiconductor substrate W is not subjected to further process and is accommodated into the cassette placed on the unloading port of the loading/unloading section  1771 . 
       FIG. 73  is a view showing the plan constitution of another example of a semiconductor substrate processing apparatus. The substrate processing apparatus differs from the substrate processing apparatus shown in  FIG. 72  in that a cap-plating unit  1750  is provided instead of the copper plating unit  1702  in  FIG. 72 . 
     A cassette  1701 - 1  accommodating the semiconductor substrates W formed plated Cu film is placed on a load port of a loading/unloading section  1701 . The semiconductor substrate W taken out from the cassette  1701 - 1  is transferred to the first polishing apparatus  1710  or second polishing apparatus  1711  in which the surface of the plated Cu film is polished. After completion of polishing of the plated Cu film, the semiconductor substrate W is cleaned in the first cleaning machine  1709 . 
     After completion of cleaning in the first cleaning machine  1709 , the semiconductor substrate W is transferred to the cap-plating unit  1750  where cap-plating is applied onto the surface of the plated Cu film with the aim of preventing oxidation of plated Cu film due to the atmosphere. The semiconductor substrate to which cap-plating has been applied is carried by the second robot  1708  from the cap-plating unit  1750  to the second cleaning unit  1707  where it is cleaned with pure water or deionized water. The semiconductor substrate after completion of cleaning is returned into the cassette  1701 - 1  placed on the loading/unloading section  1701 . 
       FIG. 74  is a view showing the plan constitution of still another example of a semiconductor substrate processing apparatus. The substrate processing apparatus differs from the substrate processing apparatus shown in  FIG. 73  in that an annealing unit  1751  is provided instead of the third cleaning machine  1709  in  FIG. 73 . 
     The semiconductor substrate W, which is polished in the polishing unit  1710  or  1711 , and cleaned in the first cleaning machine  1709  described above, is transferred to the cap-plating unit  1750  where cap-plating is applied onto the surface of the plated Cu film. The semiconductor substrate to which cap-plating has been applied is carried by the second robot  1732  from the cap-plating unit  1750  to the first cleaning unit  1707  where it is cleaned. 
     After completion of cleaning in the first cleaning machine  1709 , the semiconductor substrate W is transferred to the annealing unit  1751  in which the substrate is annealed, whereby the plated Cu film is alloyed so as to increase the electromigration resistance of the plated Cu film. The semiconductor substrate W to which annealing treatment has been applied is carried from the annealing unit  1751  to the second cleaning unit  1707  where it is cleaned with pure water or deionized water. The semiconductor substrate W after completion of cleaning is returned into the cassette  1701 - 1  placed on the loading/unloading section  1701 . 
       FIG. 75  is a view showing a plan layout constitution of another example of the substrate processing apparatus. In  FIG. 75 , portions denoted by the same reference numerals as those in  FIG. 72  show the same or corresponding portions. In the substrate processing apparatus, a pusher indexer  1725  is disposed close to a first polishing apparatus  1710  and a second polishing apparatus  1711 . Substrate placing tables  1721 ,  1722  are disposed close to a third cleaning machine  1704  and a copper plating unit  1702 , respectively. A robot  1723  is disposed close to a first cleaning machine  1709  and the third cleaning machine  1704 . Further, a robot  1724  is disposed close to a second cleaning machine  1707  and the copper plating unit  1702 , and a dry state film thickness measuring instrument  1713  is disposed close to a loading/unloading section  1701  and a first robot  1703 . 
     In the substrate processing apparatus of the above constitution, the first robot  1703  takes out a semiconductor substrate W from a cassette  1701 - 1  placed on the load port of the loading/unloading section  1701 . After the film thicknesses of a barrier layer and a seed layer are measured with the dry state film thickness measuring instrument  1713 , the first robot  1703  places the semiconductor substrate W on the substrate placing table  1721 . In the case where the dry state film thickness measuring instrument  1713  is provided on the hand of the first robot  1703 , the film thicknesses are measured thereon, and the substrate is placed on the substrate placing table  1721 . The second robot  1723  transfers the semiconductor substrate W on the substrate placing table  1721  to the copper plating unit  1702  in which a plated Cu film is formed. After formation of the plated Cu film, the film thickness of the plated Cu film is measured with a before-plating and after-plating film thickness measuring instrument  1712 . Then, the second robot  1723  transfers the semiconductor substrate W to the pusher indexer  1725  and loads it thereon. 
     [Serial Mode] 
     In the serial mode, a top ring head  1710 - 2  holds the semiconductor substrate W on the pusher indexer  1725  by suction, transfers it to a polishing table  1710 - 1 , and presses the semiconductor substrate W against a polishing surface on the polishing table  1710 - 1  to perform polishing. Detection of the end point of polishing is performed by the same method as described above. The semiconductor substrate W after completion of polishing is transferred to the pusher indexer  1725  by the top ring head  1710 - 2 , and loaded thereon. The second robot  1723  takes out the semiconductor substrate W, and carries it into the first cleaning machine  1709  for cleaning. Then, the semiconductor substrate W is transferred to the pusher indexer  1725 , and loaded thereon. 
     A top ring head  1711 - 2  holds the semiconductor substrate W on the pusher indexer  1725  by suction, transfers it to a polishing table  1711 - 1 , and presses the semiconductor substrate W against a polishing surface on the polishing table  1711 - 1  to perform polishing. Detection of the end point of polishing is performed by the same method as described above. The semiconductor substrate W after completion of polishing is transferred to the pusher indexer  1725  by the top ring head  1711 - 2 , and loaded thereon. The third robot  1724  picks up the semiconductor substrate W, and its film thickness is measured with a film thickness measuring instrument  1726 . Then, the semiconductor substrate W is carried into the second cleaning machine  1707  for cleaning. Thereafter, the semiconductor substrate W is carried into the third cleaning machine  1704 , where it is cleaned and then dried by spin-drying. Then, the semiconductor substrate W is picked up by the third robot  1724 , and placed on the substrate placing table  1722 . 
     [Parallel Mode] 
     In the parallel mode, the top ring head  1710 - 2  or  1711 - 2  holds the semiconductor substrate W on the pusher indexer  1725  by suction, transfers it to the polishing table  1710 - 1  or  1711 - 1 , and presses the semiconductor substrate W against the polishing surface on the polishing table  1710 - 1  or  1711 - 1  to perform polishing. After measurement of the film thickness, the third robot  1724  picks up the semiconductor substrate W, and places it on the substrate placing table  1722 . 
     The first robot  1703  transfers the semiconductor substrate W on the substrate placing table  1722  to the dry state film thickness measuring instrument  1713 . After the film thickness is measured, the semiconductor substrate W is returned to the cassette  1701 - 1  of the loading/unloading section  1701 . 
       FIG. 76  is a view showing another plan layout constitution of the substrate processing apparatus. The substrate processing apparatus is such a substrate processing apparatus which forms a seed layer and a plated Cu film on a semiconductor substrate W having no seed layer formed thereon, and polishes these films to form interconnects. 
     In the substrate polishing apparatus, a pusher indexer  1725  is disposed close to a first polishing apparatus  1710  and a second polishing apparatus  1711 , substrate placing tables  1721 ,  1722  are disposed close to a second cleaning machine  1707  and a seed layer forming unit  1727 , respectively, and a robot  1723  is disposed close to the seed layer forming unit  1727  and a copper plating unit  1702 . Further, a robot  1724  is disposed close to a first cleaning machine  1709  and the second cleaning machine  1707 , and a dry state film thickness measuring instrument  1713  is disposed close to a loading/unloading section  1701  and a first robot  1702 . 
     The first robot  1703  takes out a semiconductor substrate W having a barrier layer thereon from a cassette  1701 - 1  placed on the load port of the loading/unloading section  1701 , and places it on the substrate placing table  1721 . Then, the second robot  1723  transports the semiconductor substrate W to the seed layer forming unit  1727  where a seed layer is formed. The seed layer is formed by electroless-plating. The second robot  1723  enables the semiconductor substrate having the seed layer formed thereon to be measured in thickness of the seed layer by the before-plating and after-plating film thickness measuring instrument  1712 . After measurement of the film thickness, the semiconductor substrate is carried into the copper plating unit  1702  where a plated Cu film is formed. 
     After formation of the plated Cu film, its film thickness is measured, and the semiconductor substrate is transferred to a pusher indexer  1725 . A top ring  1710 - 2  or  1711 - 2  holds the semiconductor substrate W on the pusher indexer  1725  by suction, and transfers it to a polishing table  1710 - 1  or  1711 - 1  to perform polishing. After polishing, the top ring  1710 - 2  or  1711 - 2  transfers the semiconductor substrate W to a film thickness measuring instrument  1710 - 4  or  1711 - 4  to measure the film thickness. Then, the top ring  1710 - 2  or  1711 - 2  transfers the semiconductor substrate W to the pusher indexer  1725 , and places it thereon. 
     Then, the third robot  1724  picks up the semiconductor substrate W from the pusher indexer  1725 , and carries it into the first cleaning machine  1709 . The third robot  1724  picks up the cleaned semiconductor substrate W from the first cleaning machine  1709 , carries it into the second cleaning machine  1707 , and places the cleaned and dried semiconductor substrate on the substrate placing table  1722 . Then, the first robot  1703  picks up the semiconductor substrate W, and transfers it to the dry state film thickness measuring instrument  1713  in which the film thickness is measured, and the first robot  1703  carries it into the cassette  1701 - 1  placed on the unload port of the loading/unloading section  1701 . 
     In the substrate processing apparatus shown in  FIG. 76 , interconnects are formed by forming a barrier layer, a seed layer and a plated Cu film on a semiconductor substrate W having a via hole or a trench of a circuit pattern formed therein, and polishing them. 
     The cassette  1701 - 1  accommodating the semiconductor substrates W before formation of the barrier layer is placed on the load port of the loading/unloading section  1701 . The first robot  1703  takes out the semiconductor substrate W from the cassette  1701 - 1  placed on the load port of the loading/unloading section  1701 , and places it on the substrate placing table  1721 . Then, the second robot  1723  transports the semiconductor substrate W to the seed layer forming unit  1727  where a barrier layer and a seed layer are formed. The barrier layer and the seed layer are formed by electroless-plating. The second robot  1723  brings the semiconductor substrate W having the barrier layer and the seed layer formed thereon to the before-plating and after-plating film thickness measuring instrument  1712  which measures the film thicknesses of the barrier layer and the seed layer. After measurement of the film thicknesses, the semiconductor substrate W is carried into the copper plating unit  1702  where a plated Cu film is formed. 
       FIG. 77  is a view showing plan layout constitution of another example of the substrate processing apparatus. In the substrate processing apparatus, there are provided a barrier layer forming unit  1811 , a seed layer forming unit  1812 , a plating unit  1813 , an annealing unit  1814 , a first cleaning unit  1815 , a bevel and backside cleaning unit  1816 , a cap-plating unit  1817 , a second cleaning unit  1818 , a first aligner and film thickness measuring instrument  1841 , a second aligner and film thickness measuring instrument  1842 , a first substrate reversing machine  1843 , a second substrate reversing machine  1844 , a substrate temporary placing table  1845 , a third film thickness measuring instrument  1846 , a loading/unloading section  1820 , a first polishing apparatus  1821 , a second polishing apparatus  1822 , a first robot  1831 , a second robot  1832 , a third robot  1833 , and a fourth robot  1834 . The film thickness measuring instruments  1841 ,  1842 , and  1846  are units, have the same size as the frontage dimension of other units (plating, cleaning, annealing units, and the like), and are thus interchangeable. 
     In this example, an electroless Ru plating apparatus can be used as the barrier layer forming unit  1811 , an electroless Cu plating apparatus as the seed layer forming unit  1812 , and an electroplating apparatus as the plating unit  1813 . 
       FIG. 78  is a flow chart showing the flow of the respective steps in the present substrate processing apparatus. The respective steps in the apparatus will be described according to this flow chart. First, a semiconductor substrate taken out by the first robot  1831  from a cassette  1820   a  placed on the load and unload unit  1820  is placed in the first aligner and film thickness measuring unit  1841 , in such a state that its surface, to be plated, faces upward. In order to set a reference point for a position at which film thickness measurement is made, notch alignment for film thickness measurement is performed, and then film thickness data on the semiconductor substrate before formation of a Cu film are obtained. 
     Then, the semiconductor substrate is transported to the barrier layer forming unit  1811  by the first robot  1831 . The barrier layer forming unit  1811  is such an apparatus for forming a barrier layer on the semiconductor substrate by electroless Ru plating, and the barrier layer forming unit  1811  forms an Ru film as a film for preventing Cu from diffusing into an interlayer insulator film (e.g. SiO 2 ) of a semiconductor device. The semiconductor substrate discharged after cleaning/drying steps is transported by the first robot  1831  to the first aligner and film thickness measuring unit  1841 , where the film thickness of the semiconductor substrate, i.e., the film thickness of the barrier layer is measured. 
     The semiconductor substrate after film thickness measurement is carried into the seed layer forming unit  1812  by the second robot  1832 , and a seed layer is formed on the barrier layer by electroless Cu plating. The semiconductor substrate discharged after cleaning/drying steps is transported by the second robot  1832  to the second aligner and film thickness measuring instrument  1842  for determination of a notch position, before the semiconductor substrate is transported to the plating unit  1813 , which is an impregnation plating unit, and then notch alignment for Cu plating is performed by the film thickness measuring instrument  1842 . If necessary, the film thickness of the semiconductor substrate before formation of a Cu film may be measured again in the film thickness measuring instrument  1842 . 
     The semiconductor substrate which has completed notch alignment is transported by the third robot  1833  to the plating unit  1813  where Cu plating is applied to the semiconductor substrate. The semiconductor substrate discharged after cleaning/drying steps is transported by the third robot  1833  to the bevel and backside cleaning unit  1816  where an unnecessary Cu film (seed layer) at a peripheral portion of the semiconductor substrate is removed. In the bevel and backside cleaning unit  1816 , the bevel is etched in a preset time, and Cu adhering to the backside of the semiconductor substrate is cleaned with a chemical liquid such as hydrofluoric acid. At this time, before transporting the semiconductor substrate to the bevel and backside cleaning unit  1816 , film thickness measurement of the semiconductor substrate may be made by the second aligner and film thickness measuring instrument  1842  to obtain the thickness value of the Cu film formed by plating, and based on the obtained results, the bevel etching time may be changed arbitrarily to carry out etching. The region etched by bevel etching is a region which corresponds to a peripheral edge portion of the substrate and has no circuit formed therein, or a region which is not utilized finally as a chip although a circuit is formed. A bevel portion is included in this region. 
     The semiconductor substrate discharged after cleaning/drying steps in the bevel and backside cleaning unit  1816  is transported by the third robot  1833  to the substrate reversing machine  1843 . After the semiconductor substrate is turned over by the substrate reversing machine  1843  to cause the plated surface to be directed downward, the semiconductor substrate is introduced into the annealing unit  1814  by the fourth robot  1834  for thereby stabilizing an interconnection portion. Before and/or after annealing treatment, the semiconductor substrate is carried into the second aligner and film thickness measuring unit  1842  where the film thickness of a copper film formed on the semiconductor substrate is measured. Then, the semiconductor substrate is carried by the fourth robot  1834  into the first polishing apparatus  1821  in which the Cu film and the seed layer of the semiconductor substrate are polished. 
     At this time, desired abrasive grains or the like are used, but fixed abrasive may be used in order to prevent dishing and enhance flatness of the face. After completion of primary polishing, the semiconductor substrate is transported by the fourth robot  1834  to the first cleaning unit  1815  where it is cleaned. This cleaning is scrub-cleaning in which rolls having substantially the same length as the diameter of the semiconductor substrate are placed on the face and the backside of the semiconductor substrate, and the semiconductor substrate and the rolls are rotated, while pure water or deionized water is flowed, thereby performing cleaning of the semiconductor substrate. 
     After completion of the primary cleaning, the semiconductor substrate is transported by the fourth robot  1834  to the second polishing apparatus  1822  where the barrier layer on the semiconductor substrate is polished. At this time, desired abrasive grains or the like are used, but fixed abrasive may be used in order to prevent dishing and enhance flatness of the face. After completion of secondary polishing, the semiconductor substrate is transported by the fourth robot  1834  again to the first cleaning unit  1815  where scrub-cleaning is performed. After completion of cleaning, the semiconductor substrate is transported by the fourth robot  1834  to the second substrate reversing machine  1844  where the semiconductor substrate is reversed to cause the plated surface to be directed upward, and then the semiconductor substrate is placed on the substrate temporary placing table  1845  by the third robot. 
     The semiconductor substrate is transported by the second robot  1832  from the substrate temporary placing table  1845  to the cap-plating unit  1817  where cap-plating is applied onto the Cu surface with the aim of preventing oxidation of Cu due to the atmosphere. The semiconductor substrate to which cap-plating has been applied is carried by the second robot  1832  from the cover plating unit  1817  to the third film thickness measuring instrument  146  where the thickness of the copper film is measured. Thereafter, the semiconductor substrate is carried by the first robot  1831  into the second cleaning unit  1818  where it is cleaned with pure water or deionized water. The semiconductor substrate after completion of cleaning is returned into the cassette  1820   a  placed on the loading/unloading section  1820 . 
     In this manner, shown in  FIG. 95A through 95C , interconnects made of copper is formed, thereafter a protective layer is formed on the interconnects selectively by electroless cap-plating for protecting the interconnects. 
     Specifically, as shown in  FIG. 95A , an insulating film  2  of SiO 2  is deposited on a conductive layer  1   a  of a substrate  1  on which semiconductor devices are formed, a contact hole  3  and a trench  4  for an interconnect are formed by lithography and etching technology, a barrier layer  5  comprising TiN or the like is formed thereon, and a seed layer  7  is further formed thereon. 
     Then, as shown in  FIG. 95B , copper plating is applied onto the surface of the semiconductor substrate W to fill copper into the contact hole  3  and the trench  4  of the semiconductor substrate W and deposit a copper film  6  on the insulating film  2 . Thereafter, the copper film  6  on the insulating film  2  is removed by chemical mechanical polishing (CMP) to make the surface of the copper film  6 , filled into the contact hole  3  and the trench  4  for an interconnect, flush with the surface of the insulating film  2 , as shown in  FIG. 95C . An interconnect protective layer  8  is formed on the exposed metal surface. 
     In this case, the seed layer  7  may be reinforced so as to become a complete layer without a thin portion.  FIG. 94  is a flow diagram showing the flow of reinforcing process steps. 
     First, the substrate W having a seed layer  7  (see  FIG. 95A ) is transported to a pre-plating unit comprising an electroplating unit or an electroless-plating unit for depositing an additional metal on the seed layer  7  (step  1 ). 
     Next, the first-stage plating (pre-plating) is carried out in the electroplating unit or the electroless-plating unit, thereby reinforcing and completing the thin portion of the seed layer  7  (step  2 ). 
     After the completion of the first-stage plating, the substrate W is, according to necessity, transported to the washing section for washing by water (step  3 ), and is then transported a plating unit for filling the metal in the trenches. 
     Next, the second-stage plating is performed onto the surface of the substrate W in the plating unit, thereby effecting filling with copper (step  4 ). Since the seed layer  7  has been reinforced by the first-stage plating to become a complete layer without a thin portion, electric current flows evenly through the seed layer  7  in the second-stage plating, whereby the filling with copper can be completed without the formation of any voids. 
     After the completion of the second-stage plating, the substrate W is, according to necessity, transported to the washing section for washing by water (step  5 ). Thereafter, the substrate W is transported to the bevel-etching/chemical cleaning unit where the substrate W is cleaned by using a chemical liquid, and a thin copper film, etc. formed on the bevel portion of the substrate W is etched away (step  6 ). The substrate is then transported to the cleaning/drying section for cleaning and drying (step  7 ). Thereafter, the substrate is returned to the cassette of the loading/unloading section by the first transporting device (step  8 ). 
     An electrolytic plating process for plating a semiconductor substrate W shown in  FIG. 95A  will be described bellow. 
     A first plating process is performed by immersing the semiconductor substrate W into a first plating liquid, such as a high throwing power copper sulfate plating liquid used for printed circuit boards. This process forms a uniform initial thin plated film over the entire surface of the trenches formed in the surface of the semiconductor substrate W, wherein the surface includes the bottom and side walls of the trenches. Here, the high throwing power copper sulfate solution has a low concentration of copper sulfate, a high concentration of sulfuric acid, and is superior in throwing power and coating uniformity. An example composition of this solution is 5–100 g/l of copper sulfate and 100–250 g/l of sulfuric acid. 
     Since the plating liquid has a low concentration of copper sulfate and a high concentration of sulfuric acid, the conductivity of the solution is high and the polarization is great, thereby improving throwing power. As a result, plating metal is uniformly deposited on the surface of the semiconductor substrate W, eliminating unplated areas formed on the side and bottom surfaces of the fine trench. 
     After washing the semiconductor substrate W, a second plating process is performed by immersing the semiconductor substrate W into a second plating liquid, such as a copper sulfate plating liquid for decorative uses. This process fills copper into the trenches and forms a plated film having a flat surface on the surface of the substrate. Here, the copper sulfate plating liquid has a high concentration of copper sulfate and a low concentration of sulfuric acid and is superior in leveling ability. An example composition of the solution is 100–300 g/l of copper sulfate and 10–100 g/l of sulfuric acid. 
     Here, leveling ability defines a quality describing the degree of smoothness on the plating surface. 
     The pre-plating unit comprising an electroplating unit or an electroless-plating may be placed in the electroplating apparatus. 
     The aligner and film thickness measuring instrument  1841  and the aligner and film thickness measuring instrument  1842  perform positioning of the notch portion of the substrate and measurement of the film thickness. 
     The seed layer forming unit  1812  may be omitted. In this case, a plated film may be formed on a barrier layer directly in a plating unit  1813 . 
     The seed layer forming unit may be comprises an electroplating unit or an electoroless-plating unit. In this case, a seed layer made of copper film, for example, is formed on the barrier layer by electroplating or electoroless-plating, thereafter a plated film may be formed on a barrier layer in a plating unit  1813 . 
     The bevel and backside cleaning unit  1816  can perform an edge (bevel) Cu etching and a backside cleaning at the same time, and can suppress growth of a natural oxide film of copper at the circuit formation portion on the surface of the substrate.  FIG. 79  shows a schematic view of the bevel and backside cleaning unit  1816 . As shown in  FIG. 79 , the bevel and backside cleaning unit  1816  has a substrate holding portion  1922  positioned inside a bottomed cylindrical waterproof cover  1920  and adapted to rotate a substrate W at a high speed, in such a state that the face of the substrate W faces upwardly, while holding the substrate W horizontally by spin chucks  1921  at a plurality of locations along a circumferential direction of a peripheral edge portion of the substrate; a center nozzle  1924  placed above a nearly central portion of the face of the substrate W held by the substrate holding portion  1922 ; and an edge nozzle  1926  placed above the peripheral edge portion of the substrate W. The center nozzle  1924  and the edge nozzle  1926  are directed downward. A back nozzle  1928  is positioned below a nearly central portion of the backside of the substrate W, and directed upward. The edge nozzle  1926  is adapted to be movable in a diametrical direction and a height direction of the substrate W. 
     The width of movement L of the edge nozzle  1926  is set such that the edge nozzle  1926  can be arbitrarily positioned in a direction toward the center from the outer peripheral end surface of the substrate, and a set value for L is inputted according to the size, usage, or the like of the substrate W. Normally, an edge cut width C is set in the range of 2 mm to 5 mm. In the case where a rotational speed of the substrate is a certain value or higher at which the amount of liquid migration from the backside to the face is not problematic, the copper film within the edge cut width C can be removed. 
     Next, the method of cleaning with this cleaning apparatus will be described. First, the semiconductor substrate W is horizontally rotated integrally with the substrate holding portion  1922 , with the substrate being held horizontally by the spin chucks  1921  of the substrate holding portion  1922 . In this state, an acid solution is supplied from the center nozzle  1924  to the central portion of the face of the substrate W. The acid solution may be a non-oxidizing acid, and hydrofluoric acid, hydrochloric acid, sulfuric acid, citric acid, oxalic acid, or the like is used. On the other hand, an oxidizing agent solution is supplied continuously or intermittently from the edge nozzle  1926  to the peripheral edge portion of the substrate W. As the oxidizing agent solution, one of an aqueous solution of ozone, an aqueous solution of hydrogen peroxide, an aqueous solution of nitric acid, and an aqueous solution of sodium hypochlorite is used, or a combination of these is used. 
     In this manner, the copper film, or the like formed on the upper surface and end surface in the region of the peripheral edge portion C of the semiconductor substrate W is rapidly oxidized with the oxidizing agent solution, and is simultaneously etched with the acid solution supplied from the center nozzle  1924  and spread on the entire face of the substrate, whereby it is dissolved and removed. By mixing the acid solution and the oxidizing agent solution at the peripheral edge portion of the substrate, a steep etching profile can be obtained, in comparison with a mixture of them which is produced in advance being supplied. At this time, the copper etching rate is determined by their concentrations. If a natural oxide film of copper is formed in the circuit-formed portion on the face of the substrate, this natural oxide is immediately removed by the acid solution spreading on the entire face of the substrate according to rotation of the substrate, and does not grow any more. After the supply of the acid solution from the center nozzle  1924  is stopped, the supply of the oxidizing agent solution from the edge nozzle  1926  is stopped. As a result, silicon exposed on the surface is oxidized, and deposition of copper can be suppressed. 
     On the other hand, an oxidizing agent solution and a silicon oxide film etching agent are supplied simultaneously or alternately from the back nozzle  1928  to the central portion of the backside of the substrate. Therefore, copper or the like adhering in a metal form to the backside of the semiconductor substrate W can be oxidized with the oxidizing agent solution, together with silicon of the substrate, and can be etched and removed with the silicon oxide film etching agent. This oxidizing agent solution is preferably the same as the oxidizing agent solution supplied to the face, because the types of chemicals are decreased in number. Hydrofluoric acid can be used as the silicon oxide film etching agent, and if hydrofluoric acid is used as the acid solution on the face of the substrate, the types of chemicals can be decreased in number. Thus, if the supply of the oxidizing agent is stopped first, a hydrophobic surface is obtained. If the etching agent solution is stopped first, a water-saturated surface (a hydrophilic surface) is obtained, and thus the backside surface can be adjusted to a condition which will satisfy the requirements of a subsequent process. 
     In this manner, the acid solution, i.e., etching solution is supplied to the substrate to remove metal ions remaining on the surface of the substrate W. Then, pure water is supplied to replace the etching solution with pure water and remove the etching solution, and then the substrate is dried by spin-drying. In this way, removal of the copper film in the edge cut width C at the peripheral edge portion on the face of the semiconductor substrate, and removal of copper contaminants on the backside are performed simultaneously to thus allow this treatment to be completed, for example, within 80 seconds. The etching cut width of the edge can be set arbitrarily (to 2 mm to 5 mm), but the time required for etching does not depend on the cut width. 
     Annealing treatment performed before the CMP process and after plating has a favorable effect on the subsequent CMP treatment and on the electrical characteristics of interconnection. Observation of the surface of broad interconnection (unit of several micrometers) after the CMP treatment without annealing showed many defects such as microvoids, which resulted in an increase in the electrical resistance of the entire interconnection. Execution of annealing ameliorated the increase in the electrical resistance. In the absence of annealing, thin interconnection showed no voids. Thus, the degree of grain growth is presumed to be involved in these phenomena. That is, the following mechanism can be speculated: Grain growth is difficult to occur in thin interconnection. In broad interconnection, on the other hand, grain growth proceeds in accordance with annealing treatment. During the process of grain growth, ultrafine pores in the plated film, which are too small to be seen by the SEM (scanning electron microscope), gather and move upward, thus forming microvoid-like depressions in the upper part of the interconnection. The annealing conditions in the annealing unit  1814  are such that hydrogen (2% or less) is added in a gas atmosphere, the temperature is in the range of 300° C. to 400° C., and the time is in the range of 1 to 5 minutes. Under these conditions, the above effects were obtained. 
       FIGS. 82 and 83  show the annealing unit  1814 . The annealing unit  1814  comprises a chamber  1002  having a gate  1000  for taking in and taking out the semiconductor substrate W, a hot plate  1004  disposed at an upper position in the chamber  1002  for heating the semiconductor substrate W to e.g. 400° C., and a cool plate  1006  disposed at a lower position in the chamber  1002  for cooling the semiconductor substrate W by, for example, flowing a cooling water inside the plate. The annealing unit  1002  also has a plurality of vertically movable elevating pins  1008  penetrating the cool plate  1006  and extending upward and downward therethrough for placing and holding the semiconductor substrate W on them. The annealing unit further includes a gas introduction pipe  1010  for introducing an antioxidant gas between the semiconductor substrate W and the hot plate  1004  during annealing, and a gas discharge pipe  1012  for discharging the gas which has been introduced from the gas introduction pipe  1010  and flowed between the semiconductor substrate W and the hot plate  1004 . The pipes  1010  and  1012  are disposed on the opposite sides of the hot plate  1004 . 
     The gas introduction pipe  1010  is connected to a mixed gas introduction line  1022  which in turn is connected to a mixer  1020  where a N 2  gas introduced through a N 2  gas introduction line  1016  containing a filter  1014   a , and a H 2  gas introduced through a H 2  gas introduction line  1018  containing a filter  1014   b , are mixed to form a mixed gas which flows through the line  1022  into the gas introduction pipe  1010 . 
     In operation, the semiconductor substrate W, which has been carried in the chamber  1002  through the gate  1000 , is held on the elevating pins  1008  and the elevating pins  1008  are raised up to a position at which the distance between the semiconductor substrate W held on the lifting pins  1008  and the hot plate  1004  becomes e.g. 0.1–1.0 mm. In this state, the semiconductor substrate W is then heated to e.g. 400° C. through the hot plate  1004  and, at the same time, the antioxidant gas is introduced from the gas introduction pipe  1010  and the gas is allowed to flow between the semiconductor substrate W and the hot plate  1004  while the gas is discharged from the gas discharge pipe  1012 , thereby annealing the semiconductor substrate W while preventing its oxidation. The annealing treatment may be completed in about several tens of seconds to 60 seconds. The heating temperature of the substrate may be selected in the range of 100–600° C. 
     After the completion of the annealing, the elevating pins  1008  are lowered down to a position at which the distance between the semiconductor substrate W held on the elevating pins  1008  and the cool plate  1006  becomes e.g. 0–0.5 mm. In this state, by introducing a cooling water into the cool plate  1006 , the semiconductor substrate W is cooled by the cool plate to a temperature of 100° C. or lower in e.g. 10–60 seconds. The cooled semiconductor substrate is sent to the next step. 
     A mixed gas of N 2  gas with several % of H 2  gas is used as the above antioxidant gas. However, N 2  gas may be used singly. 
     The annealing unit may be placed in the electroplating apparatus. 
       FIG. 80  is a schematic constitution drawing of the electroless-plating apparatus. As shown in  FIG. 80 , this electroless-plating apparatus comprises holding means  1911  for holding a semiconductor substrate W to be plated on its upper surface, a dam member  1931  for contacting a peripheral edge portion of a surface to be plated (upper surface) of the semiconductor substrate W held by the holding means  1911  to seal the peripheral edge portion, and a shower head  1941  for supplying a plating liquid to the surface, to be plated, of the semiconductor substrate W having the peripheral edge portion sealed with the dam member  1931 . The electroless-plating apparatus further comprises cleaning liquid supply means  1951  disposed near an upper outer periphery of the holding means  1911  for supplying a cleaning liquid to the surface, to be plated, of the semiconductor substrate W, a recovery vessel  1961  for recovering a cleaning liquid or the like (plating waste liquid) discharged, a plating liquid recovery nozzle  1965  for sucking in and recovering the plating liquid held on the semiconductor substrate W, and a motor M for rotationally driving the holding means  1911 . The respective members will be described below. 
     The holding means  1911  has a substrate placing portion  1913  on its upper surface for placing and holding the semiconductor substrate W. The substrate placing portion  1913  is adapted to place and fix the semiconductor substrate W. Specifically, the substrate placing portion  1913  has a vacuum attracting mechanism (not shown) for attracting the semiconductor substrate W to a backside thereof by vacuum suction. A backside heater  1915 , which is planar and heats the surface, to be plated, of the semiconductor substrate W from underside to keep it warm, is installed on the backside of the substrate placing portion  1913 . The backside heater  1915  is composed of, for example, a rubber heater. This holding means  1911  is adapted to be rotated by the motor M and is movable vertically by raising and lowering means (not shown). 
     The dam member  1931  is tubular, has a seal portion  1933  provided in a lower portion thereof for sealing the outer peripheral edge of the semiconductor substrate W, and is installed so as not to move vertically from the illustrated position. 
     The shower head  1941  is of a structure having many nozzles provided at the front end for scattering the supplied plating liquid in a shower form and supplying it substantially uniformly to the surface, to be plated, of the semiconductor substrate W. The cleaning liquid supply means  1951  has a structure for ejecting a cleaning liquid from a nozzle  1953 . 
     The plating liquid recovery nozzle  1965  is adapted to be movable upward and downward and swingable, and the front end of the plating liquid recovery nozzle  1965  is adapted to be lowered inwardly of the dam member  1931  located on the upper surface peripheral edge portion of the semiconductor substrate W and to suck in the plating liquid on the semiconductor substrate W. 
     Next, the operation of the electroless-plating apparatus will be described. First, the holding means  1911  is lowered from the illustrated state to provide a gap of a predetermined dimension between the holding means  1911  and the dam member  1931 , and the semiconductor substrate W is placed on and fixed to the substrate placing portion  1913 . An 8 inch wafer, for example, is used as the semiconductor substrate W. 
     Then, the holding means  1911  is raised to bring its upper surface into contact with the lower surface of the dam member  1931  as illustrated, and the outer periphery of the semiconductor substrate W is sealed with the seal portion  1933  of the dam member  1931 . At this time, the surface of the semiconductor substrate W is in an open state. 
     Then, the semiconductor substrate W itself is directly heated by the backside heater  1915  to render the temperature of the semiconductor substrate W, for example, 70° C. (maintained until termination of plating). Then, the plating liquid heated, for example, to 50° C. is ejected from the shower head  1941  to pour the plating liquid over substantially the entire surface of the semiconductor substrate W. Since the surface of the semiconductor substrate W is surrounded by the dame member  1931 , the poured plating liquid is all held on the surface of the semiconductor substrate W. The amount of the supplied plating liquid may be a small amount which will become a 1 mm thickness (about 30 ml) on the surface of the semiconductor substrate W. The depth of the plating liquid held on the surface to be plated may be 10 mm or less, and may be even 1 mm as in this embodiment. If a small amount of the supplied plating liquid is sufficient, the heating apparatus for heating the plating liquid may be of a small size. In this example, the temperature of the semiconductor substrate W is raised to 70° C., and the temperature of the plating liquid is raised to 50° C. by heating. Thus, the surface, to be plated, of the semiconductor substrate W becomes, for example, 60° C., and hence a temperature optimal for a plating reaction in this example can be achieved. 
     The semiconductor substrate W is instantaneously rotated by the motor M to perform uniform liquid wetting of the surface to be plated, and then plating of the surface to be plated is performed in such a state that the semiconductor substrate W is in a stationary state. Specifically, the semiconductor substrate W is rotated at 100 rpm or less for only 1 second to uniformly wet the surface, to be plated, of the semiconductor substrate W with the plating liquid. Then, the semiconductor substrate W is kept stationary, and electroless-plating is performed for 1 minute. The instantaneous rotating time is 10 seconds or less at the longest. 
     After completion of the plating treatment, the front end of the plating liquid recovery nozzle  1965  is lowered to an area near the inside of the dam member  1931  on the peripheral edge portion of the semiconductor substrate W to suck in the plating liquid. At this time, if the semiconductor substrate W is rotated at a rotational speed of, for example, 100 rpm or less, the plating liquid remaining on the semiconductor substrate W can be gathered in the portion of the dam member  1931  on the peripheral edge portion of the semiconductor substrate W under centrifugal force, so that recovery of the plating liquid can be performed with a good efficiency and a high recovery rate. The holding means  1911  is lowered to separate the semiconductor substrate W from the dam member  1931 . The semiconductor substrate W is started to be rotated, and the cleaning liquid (ultrapure water) is jetted at the plated surface of the semiconductor substrate W from the nozzle  1953  of the cleaning liquid supply means  1951  to cool the plated surface, and simultaneously perform dilution and cleaning, thereby stopping the electroless-plating reaction. At this time, the cleaning liquid jetted from the nozzle  1953  may be supplied to the dam member  1931  to perform cleaning of the dam member  1931  at the same time. The plating waste liquid at this time is recovered into the recovery vessel  1961  and discarded. 
     Then, the semiconductor substrate W is rotated at a high speed by the motor M for spin-drying, and then the semiconductor substrate W is removed from the holding means  1911 . 
       FIG. 81  is a schematic constitution drawing of another electroless-plating. The electroless-plating apparatus of  FIG. 81  is different from the electroless-plating apparatus of  FIG. 80  in that instead of providing the backside heater  1915  in the holding means  1911 , lamp heaters  1917  are disposed above the holding means  1911 , and the lamp heaters  1917  and a shower head  1941 - 2  are integrated. For example, a plurality of ring-shaped lamp heaters  1917  having different radii are provided concentrically, and many nozzles  1943 - 2  of the shower head  1941 - 2  are open in a ring form from the gaps between the lamp heaters  1917 . The lamp heaters  1917  may be composed of a single spiral lamp heater, or may be composed of other lamp heaters of various structures and arrangements. 
     Even with this constitution, the plating liquid can be supplied from each nozzle  1943 - 2  to the surface, to be plated, of the semiconductor substrate W substantially uniformly in a shower form. Further, heating and heat retention of the semiconductor substrate W can be performed by the lamp heaters  1917  directly uniformly. The lamp heaters  1917  heat not only the semiconductor substrate W and the plating liquid, but also ambient air, thus exhibiting a heat retention effect on the semiconductor substrate W. 
     Direct heating of the semiconductor substrate W by the lamp heaters  1917  requires the lamp heaters  1917  with a relatively large electric power consumption. In place of such lamp heaters  1917 , lamp heaters  1917  with a relatively small electric power consumption and the backside heater  1915  shown in  FIG. 79  may be used in combination to heat the semiconductor substrate W mainly with the backside heater  1915  and to perform heat retention of the plating liquid and ambient air mainly by the lamp heaters  1917 . In the same manner as in the aforementioned embodiment, means for directly or indirectly cooling the semiconductor substrate W may be provided to perform temperature control. 
     The cap-plating described above is preferably performed by electroless-plating process, but may be performed by electroplating process. 
     Although certain preferred embodiments of the present invention have been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims. 
     INDUSTRIAL APPLICABILITY 
     This invention is suitable to a substrate processing method, and more particularly, to those used to fill fine recesses formed on the surface of a semiconductor substrate with copper, thereby forming a copper interconnection pattern.