Patent Publication Number: US-2007107845-A1

Title: Semiconductor processing system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application is a Continuation of and claims the benefit of priority under 35 U.S.C. §120 from U.S. Ser. No. 10/486,511, filed on Feb. 12, 2004, which is a national stage of international filing PCT/JP02/07817 filed Jul. 31, 2002. This application also claims the benefit of priority under 35 U.S.C. §119 from Japanese Patent Application No. 2001-246088, filed Aug. 14, 2001, the entire contents of each which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD  
      The present invention relates to a semiconductor processing system having a plurality of vacuum processing apparatuses for performing predetermined processes on a target substrate, such as a semi-conductor wafer. The term “semiconductor process” used herein includes various kinds of processes which are performed to manufacture a semiconductor device or a structure having wiring layers, electrodes, and the like to be connected to a semiconductor device, on a target substrate, such as a semiconductor wafer or an LCD substrate, by forming semiconductor layers, insulating layers, and conductive layers in predetermined patterns on the target substrate.  
     BACKGROUND ART  
      In the process of manufacturing semiconductor integrated circuits, a wafer is subjected to various processes, such as film-formation, etching, oxidation, and diffusion. Owing to the demands of increased miniaturization and integration of semiconductor integrated circuits, the throughput and yield involving these processes need to be increased. In light of this, there is a semiconductor processing system of the so-called cluster tool type, which has a plurality of process chambers for performing the same process, or a plurality of process chambers for performing different processes, connected to a common transfer chamber. With a system of this type, various steps can be performed in series, without exposing a wafer to air. For example, Jpn. Pat. Appln. KOKAI Publication Nos. 2000-208589 and 2000-299367 disclose a semiconductor processing system of the cluster tool type. The assignee of the present invention also filed Jpn. Pat. Appln. No. 2001-060968 disclosing an improved semiconductor processing system of the cluster tool type.  
       FIG. 14  is a structural view schematically showing a conventional processing system of the cluster tool type. As shown in  FIG. 14 , the processing system  2  includes three processing apparatuses  4 A,  4 B, and- 4 C, a first transfer chamber  6 , two load-lock chambers  8 A and  8 B provided with a pre-heating mechanism or cooling mechanism, a second transfer chamber  10 , and two cassette chambers  12 A and  12 B. The three processing apparatuses  4 A to  4 C are connected to the first transfer chamber  6  in common. The two load-lock chambers  8 A and  8 B are disposed in parallel with each other between the first and second transfer chambers  6  and  10 . The two cassette chambers  12 A and  12 B are connected to the second transfer chamber  10 . A gate valve G to be airtightly opened/closed is interposed between each two of the chambers.  
      The first and second transfer chambers  6  and  10  are respectively provided with first and second transfer arm devices  14  and  16  disposed therein, each of which is formed of an articulated structure that can extend, contract, and rotate. Each of the arm devices  14  and  16  is arranged to hold a semiconductor wafer W to transfer it. The second transfer chamber  10  is provided with an alignment mechanism  22  disposed therein, which is formed of a rotary table  18  and an optical sensor  20 . The alignment mechanism  22  is arranged to rotate a wafer W transferred from the cassette chamber  12 A or  12 B, and detect its orientation flat or notch to perform alignment thereon.  
      When a semiconductor wafer W is processed, an unprocessed semiconductor wafer W is first taken out of a cassette C placed in one of the cassette chambers, e.g., a cassette chamber  12 A, by the second transfer arm device  16  disposed in the second transfer chamber  10 , which has been kept at atmospheric pressure with an N2 atmosphere. Then, the wafer W is transferred by the arm device  16  and placed on the rotary table  18  of the alignment mechanism  22  disposed in the second transfer chamber  10 . The arm device  16  is kept stationary on standby while the rotary table  18  rotates to perform alignment. The time period necessary for this alignment operation is, e.g., about 10 to 20 seconds.  
      After the alignment operation, the aligned wafer W is held again by the arm device  16 , which has been on standby, and transferred into one of the load-lock chambers, e.g., the chamber  8 A. The wafer is pre-heated in the load-lock chamber  8 A, as needed, and, at the same time, the interior of the load-lock chamber  8 A is vacuum-exhausted to a predetermined pressure. The time period necessary for performing this pre-heating or vacuum-exhaust is, e.g., about 30 to 40 seconds.  
      After the pre-heating operation, the gate valve G between the load-lock chamber  8 A and the first transfer chamber  6 , which is set at vacuum in advance, is opened to make them communicate with each other. Then, the pre-heated wafer W is held by the first transfer arm device  14  and transferred into a predetermined processing apparatus, e.g.,  4 A. Then, a predetermined process, such as a film-formation process of a metal film, insulating film, or the like, is performed in the processing apparatus  4 A. The time period necessary for performing this process is, e.g., about 60 to 90 seconds.  
      The processed semiconductor wafer W is transferred, through a route reverse to the route described above, to, e.g., the original cassette C placed in the cassette chamber  12 A. In this route to return the processed wafer W, the other load-lock chamber  8 B is used, for example, and the wafer W is transferred after it is cooled to a predetermined temperature. The time period necessary for performing this cooling and returning to atmospheric pressure is about 30 to 40 seconds. Before the processed wafer W is transferred into the cassette C, alignment may be performed by the alignment mechanism  22 , as needed.  
      As semiconductor wafer processes progress in level′ of miniaturization and integration, decrease in film thickness, and increase in the number of layers, integrated circuits are increasingly required to have diversified functions. As a result, manufacture of semiconductor integrated circuits tends to shift from small item large volume production to large item small volume production.  
      In the processing system of the cluster tool type shown in  FIG. 14 , the processing apparatuses  4 A to  4 C connected by the gate valves G can be detached and replaced with other processing apparatuses to perform other vacuum processes, as needed. However, the processing system may be required to be used in different ways, due to the recent trend described above. For example, there may be a case where a processing apparatus for performing another vacuum process needs to be added to the processing system, a processing apparatus for performing a normal pressure process needs to be added to the processing system, or a processing apparatus for performing a vacuum process needs to be replaced with a processing apparatus for performing a normal pressure process. However, the processing system shown in  FIG. 14  has fixed structures, except for the three vacuum processing apparatuses  4 A to  4 , and thus is very difficult to comply with the request described above.  
      One solution is to provide two apparatuses: one processing apparatus for performing a vacuum atmosphere process, and another for performing a normal pressure atmosphere process, both of which are connected to the first transfer chamber  6 . In this case, however, it takes a long time to perform pressure adjustment between chambers when wafers are transferred, thereby inevitably bringing about a substantial decrease in throughput, to an unpractical level.  
     DISCLOSURE OF INVENTION  
      Accordingly, an object of the present invention is to provide a semiconductor processing system that can easily incorporate either of additional processing apparatuses for performing a vacuum atmosphere process and an atmospheric pressure atmosphere process.  
      According to a first aspect of the present invention, there is provided a semiconductor processing system comprising:  
      an entrance transfer chamber with an atmospheric pressure atmosphere, which has a loading port for loading a target substrate into the semiconductor processing system;  
      a common transfer chamber with a vacuum atmosphere, which is connected to the entrance transfer chamber through an intermediate structure that forms a route for transferring the target substrate;  
      a plurality of vacuum processing apparatuses connected to the common transfer chamber, each of which is configured to perform a predetermined process on the target substrate within a vacuum atmosphere;  
      a transfer arm device disposed in the entrance transfer chamber and configured to transfer the target substrate between a portion outside the semiconductor processing system and the intermediate structure; and  
      a transfer arm device disposed in the common transfer chamber and configured to transfer the target substrate between the intermediate structure and the vacuum processing apparatuses, 
          wherein the intermediate structure comprises a transfer passage that connects the entrance transfer chamber and the common transfer chamber to allow the target substrate to pass therein, and includes a first buffer chamber, a middle transfer chamber, and a second buffer chamber connected in series in this order and detachable from each other, such that the first and second buffer chambers are detachably connected to the entrance transfer chamber and the common transfer chamber, respectively,        

      an additional processing apparatus detachably connected to the middle transfer chamber, and  
      a transfer arm device disposed in the middle transfer chamber and configured to transfer the target substrate between the first buffer chamber, the additional processing apparatus, and the second buffer chamber; and  
      the intermediate structure is selectively arranged to be in one of first and second states, the first state being a state where the additional processing apparatus is set to perform a predetermined process on the target substrate within a vacuum atmosphere, while the first buffer chamber is set to be a load-lock chamber for adjusting pressure between atmospheric pressure and vacuum, and the second state being a state where the additional processing apparatus is set to perform a predetermined process on the target substrate within an atmospheric pressure atmosphere, while the second buffer chamber is set to be a load-lock chamber for adjusting pressure between atmospheric pressure and vacuum.  
      According to a second aspect of the present invention, there is provided a semiconductor processing system comprising:  
      an entrance transfer chamber with an atmospheric pressure atmosphere, which has a loading port for loading a target substrate into the semiconductor processing system;  
      a common transfer chamber with a vacuum atmosphere, which is connected to the entrance transfer chamber through first and second intermediate structures that form routes parallel with each other for transferring the target substrate;  
      a plurality of vacuum processing apparatuses connected to the common transfer chamber, each of which is configured to perform a predetermined process on the target substrate within a vacuum atmosphere;  
      a transfer arm device disposed in the entrance transfer chamber and configured to transfer the target substrate between a portion outside the semiconductor processing system and the first and second intermediate structures; and  
      a transfer arm device disposed in the common transfer chamber and configured to transfer the target substrate between the first and second intermediate structures and the vacuum processing apparatuses,  
      wherein each of the first and second intermediate structures comprises  
      a transfer passage that connects the entrance transfer chamber and the common transfer chamber to allow the target substrate to pass therein, and includes a first buffer chamber, a middle transfer chamber, and a second buffer chamber connected in series in this order and detachable from each other, such that the first and second buffer chambers are detachably connected to the entrance transfer chamber and the common transfer chamber, respectively,  
      an additional processing apparatus detachably connected to the middle transfer chamber, and  
      a transfer arm device disposed in the middle transfer chamber and configured to transfer the target substrate between the first buffer chamber, the additional processing apparatus, and the second buffer chamber. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       FIG. 1  is a schematic plan view showing one state of a semiconductor processing system according to an embodiment of the present invention;  
       FIG. 2  is a plan view showing the processing system of  FIG. 1  in detail;  
       FIG. 3  is an enlarged sectional view taken along line III-III in  FIG. 2 ;  
       FIG. 4  is an enlarged perspective view showing a gate valve, used in the processing system of  FIG. 1 ;  
       FIG. 5  is an enlarged perspective view showing a sleeve pipe having no valve function, used in the processing system of  FIG. 1 ;  
       FIGS. 6A and 6B  are enlarged sectional views showing a first buffer chamber, used in the processing system of  FIG. 1 ;  
       FIG. 7  is a schematic plan view showing another state of the processing system of  FIG. 1 , obtained by changing some modules;  
       FIG. 8  is a plan view of the state of the processing system shown in  FIG. 7 ;  
       FIG. 9  is an enlarged sectional view taken along line IX-IX in  FIG. 8 ;  
       FIG. 10  is a schematic plan view showing still another state of the processing system of  FIG. 1 , obtained by changing some modules;  
       FIG. 11  is a schematic plan view showing a semiconductor processing system according to another embodiment of the present invention;  
       FIG. 12  is a schematic plan view showing a semiconductor processing system according to still another embodiment of the present invention;  
       FIG. 13  is a schematic plan view showing a semiconductor processing system according to still another embodiment of the present invention; and  
       FIG. 14  is a structural view schematically showing a conventional semiconductor processing system of the cluster tool type. 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION  
      Embodiments of the present invention will be described hereinafter with reference to the accompanying drawings. In the following description, the constituent elements having substantially the same function and arrangement are denoted by the same reference numerals, and a repetitive description will be made only when necessary.  
       FIG. 1  is a schematic plan view showing one state of a semiconductor processing system according to an embodiment of the present invention.  FIG. 2  is a plan view showing the processing system of  FIG. 1  in detail.  FIG. 3  is an enlarged sectional view taken along line III-III in  FIG. 2 . The shaded portions in  FIG. 1  denote portions that are kept in continuous vacuum when the system operates. The shaded portions in the plan views shown in  FIGS. 7, 10 ,  12 , and  13  denote the same.  
      As shown in  FIGS. 1 and 2 , the processing system  30  includes an entrance transfer chamber  32  with an atmospheric pressure atmosphere, into which a target substrate, such as a semiconductor wafer W, is transferred. The processing system  30  also includes a common transfer chamber  36  with a vacuum atmosphere, to which a plurality of, e.g., four in this illustrated example, vacuum processing apparatuses  34 A,  34 B,  34 C, and  34 D are connected therearound. The entrance transfer chamber  32  and common transfer chamber  36  are connected to each other by a plurality of routes for transferring semiconductor wafers W, e.g., two parallel transfer passages  38 A and  38 B in this illustrated example. The transfer passages  38 A and  38 B are formed as parts of intermediate structures  37 A and  37 B, respectively, disposed between the entrance transfer chamber  32  and common transfer chamber  36 .  
      The common transfer chamber  36  is formed of, e.g., an aluminum container having a hexagonal shape as a whole. A gas supply system  40  and a vacuum exhaust system  42  are connected to the common transfer chamber  36 , so that it can be supplied with an inactive gas, such as N2 gas, and can be vacuum-exhausted.  
      Ports  44  for transferring wafers W therethrough are respectively formed in two sides of the common transfer chamber  36  adjacent to each other. A common transfer arm device  46 , which can extend, contract, and rotate, is disposed at the center of the common transfer chamber  36 . The arm device  46  has two picks  48 , so that it can handle and transfer two wafers W at a time.  
      The four processing apparatuses  34 A to  34 D are connected to the other four sides of the common transfer chamber  36  through gate valves G 1  to G 4 , respectively. Each of the processing apparatuses  34 A to  34 D can be supplied with a process gas and can be vacuum-exhausted, so that it can perform its own vacuum process within a vacuum atmosphere.  
      On the other hand, the entrance transfer chamber  32  is formed of, e.g., a stainless steel container having a long thin configuration. A plurality of, e.g., three in this illustrated example, openings  50  are formed in one long side of the entrance transfer chamber  32 . A table  52  for placing a cassette container C thereon is disposed outside each of the openings  50  to constitute a loading port  54 . The cassette container C may be of the open type or the closed type with an openable lid. In either case, the cassette container C is structured to store a plurality of, e.g., about 25, wafers W.  
      A guide rail  56  is disposed in the entrance transfer chamber  32  and extends in its longitudinal direction. An entrance transfer arm device  58  is arranged to be movable along the guide rail  56 . The arm device  58  is formed of an articulated arm device that can extend, contract, and rotate. The arm device  58  has two picks  60 , so that it can handle and transfer two wafers W at a time.  
      An orientor  66  including a rotary table  62  and an optical sensor  64  is disposed at one end of the entrance transfer chamber  32  in the longitudinal direction. The orientor  66  is arranged to detect the notch or orientation flat of a wafer W to perform alignment thereon.  
      Two opening ports  68  are formed in the other long side of the entrance transfer chamber  32 . The two opening ports  68  are respectively connected to the transfer passages  38 A and  38 B of the intermediate structures  37 A and  37 B.  
      More specifically, each of the transfer passages  38 A and  38 B is formed of a first buffer chamber  70 , a middle transfer chamber  72 , and a second buffer chamber  74 , connected in this order from the entrance transfer chamber  32  toward the common transfer chamber  36 . Each of the chambers  70 ,  72 , and  74  is formed of, e.g., an aluminum container defining a module. Each of two opposite ends of the container has an opening provided with a connection flange. The second buffer chamber  74  has a bent shape, so that its center faces the swivel center of the common transfer arm device  46  disposed in the common transfer chamber  36 .  
      In the system shown in  FIG. 1 , the first buffer chamber  70  is set to be a load-lock chamber for adjusting pressure between atmospheric pressure and vacuum. The first buffer chamber  70  is connected to the adjacent chambers (the entrance transfer chamber  32  and middle transfer chamber  72 ) on both sides respectively through gate valves  78 .  FIG. 4  is an enlarged perspective view showing one gate valve  78 . On the other hand, the second buffer chamber  74  is set to be a chamber having a vacuum atmosphere common to the middle transfer chamber  72  and common transfer chamber  36 . The second buffer chamber  74  is connected to the adjacent chambers (the middle transfer chamber  72  and common transfer chamber  36 ) on both sides respectively through sleeve pipes  80  having no valve function.  FIG. 5  is an enlarged perspective view showing one sleeve pipe  80 .  
      As shown in  FIG. 4 , the gate valve  78  includes a hollow valve casing  82  that has a size to allow a wafer in a horizontal state to pass therethrough. The valve casing  82  is provided with flanges  78 A respectively at two opposite sides, and screw holes  86  are formed almost equidistantly in each flange  78 A. The valve casing  82  is also provided with a disc receiving portion  84  for receiving a valve disc, which extends on one side. The valve disc (not shown) moves between the disc receiving portion  84  and valve casing  82  to open/close the gate valve  78 .  
      As shown in  FIG. 5 , the sleeve pipe  80  includes a hollow pipe that has a size to allow a wafer in a horizontal state to pass therethrough, as in the valve casing  82 . The hollow pipe is provided with flanges  80 A respectively at two opposite sides, and screw holes  88  are formed almost equidistantly in each flange  80 A.  
      The entire width L 1  of the sleeve pipe  80  and the entire width L 2  of the gate valve  78  are preset to be the same, so that replacement is made easy. The flange  78 A or  80 A is tightened and fixed by a number of bolts  90  to the flange of the adjacent first buffer chamber  70 , middle transfer chamber  72 , or second buffer chamber  74 . A sealing member  92 , such as an O-ring, is interposed between the flanges to form an airtight connection state. The chambers  70 ,  72 , and  74 , gate valves  78 , and sleeve pipes  80  are easily attached/detached relative to each other by the bolts  90 .  
      A vacuum exhaust system  94  and a gas supply system  96  for clean air or an inactive gas, such as N2 gas, are connected to the first buffer chamber  70 . Namely, the first buffer chamber  70  has a so-called load-lock function to select a vacuum state and an atmospheric pressure state. Thus, the first buffer chamber  70  can intermediate between the vacuum atmosphere side and atmospheric pressure side (normal pressure side).  
      The entrance transfer chamber  32  always has a substantially atmospheric pressure (normal pressure) atmosphere therein. On the other hand, the middle transfer chamber  72 , second buffer chamber  74 , and common transfer chamber  36  always communicate with each other and have a vacuum atmosphere.  
      The first buffer chamber  70  has a structure the same as that disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2000-299367. Specifically, as also shown in  FIGS. 3, 6A  and  6 B, the first buffer chamber  70  includes a pre-heating mechanism  120  for pre-heating a wafer W, and a cooling mechanism  122  for cooling a wafer W.  FIG. 6A  shows a state where both of the pre-heating mechanism and cooling mechanism are in operation, while  FIG. 6B  shows a state where the upper switching lid  136  of the pre-heating mechanism is at a lower position.  
      More specifically, in the pre-heating mechanism  120 , an opening is formed in the upper partition wall  124  of the first buffer chamber  70 . An upper projecting receptacle  126  is attached to this opening in an airtight state and extends upward. The ceiling of the upper projecting receptacle  126  is opened, on which a transmission window  130  of, e.g., quartz is disposed airtightly by a sealing member  128 , such as an O-ring. A casing  132  is placed above the transmission window  130 , and a plurality of heating lamps  134  are disposed in the casing  132 .  
      The upper switching lid  136  is disposed in the lower opening of the upper projecting receptacle  126  airtightly by a sealing member  138 , such as an O-ring. More specifically, the upper switching lid  136  is supported on its one side to be movable up and down by an upper air cylinder  140 , which is fixed to the upper partition wall  124 . When the upper switching lid  136  is raised by the air cylinder  140 , it closes the lower opening of the upper projecting receptacle  126  to form an airtight space therein, as shown in  FIG. 6A .  
      A plurality of, e.g., three, support pins  142  (only two of them are illustrated) stand on the upper surface of the upper switching lid  136 . The support pins  142  support a wafer W, while being in contact with the bottom of the wafer W. The upper switching lid  136  is provided with a reinforcing member  146  having an opened ceiling and sidewalls with two horizontally long transfer ports  144  (only one of them is illustrated in  FIGS. 6A and 6B ). A wafer W is transferred into and out of the upper switching lid  136  through the two transfer ports  144  in both of the left and right directions. In this illustrated example, one transfer port  144  is shown in the front side, for ease of understanding.  
      A vacuum exhaust system  94  connected to a vacuum pump (not shown), or the like, is connected to the sidewall of the upper projecting receptacle  126 . The vacuum exhaust system  94  exhausts gas removed from the surface of a wafer in pre-heating the wafer (in a degas process). A supply system  96  for N2 gas or the like is also connected to the sidewall of the upper projecting receptacle  126 .  
      On the other hand, in the cooling mechanism  122 , an opening is formed in the lower partition wall  148  of the first buffer chamber  70 . A lower projecting receptacle  150  is attached to this opening in an airtight state and extends downward. A lower switching lid  152  is disposed in the upper opening of the lower projecting receptacle  150  airtightly by a sealing member  154 , such as an O-ring. More specifically, the lower switching lid  152  is supported on its one side to be movable up and down by a lower air cylinder  156 , which is fixed to the lower partition wall  148 . When the lower switching lid  152  is lowered by the air cylinder  156 , it closes the upper opening of the lower projecting receptacle  150  to form an airtight space therein, as shown in  FIG. 6A .  
      The lower switching lid  152  is provided with a reinforcing member  160  thereon, having sidewalls with two transfer ports  158  each having a long sideways shape. A wafer W is transferred into and out of the lower switching lid  152  through the two transfer ports  158  in both of the left and right directions. In this illustrated example, one transfer port  158  is shown in the front side, for ease of understanding. A plurality of, e.g., three, support pins  162  (only two of them are illustrated) stand on the upper surface of the bottom of the reinforcing member  160 . The support pins  162  support a wafer W, while being in contact with the bottom of the wafer W.  
      A cooling gas system  164  for selectively feeding a cooling gas, such as cooled N2 gas, is connected to the bottom of the lower projecting receptacle  150 . A vacuum exhaust system  94  connected to a vacuum pump (not shown), or the like, is also connected to the bottom of the lower projecting receptacle  150 . This arrangement allows the cooling gas to be supplied and exhausted in cooling a wafer. A gas supply system  96  for supplying N2 gas or the like is also connected to the lower projecting receptacle  150 .  
      The first buffer chamber  70  may be provided with only one of the cooling mechanism  122  and pre-heating mechanism  120 . The interior of the first buffer chamber  70  may be arranged to be supplied with N2 gas and vacuum-exhausted as a whole. In this case, the upper switching lid  136  or lower switching lid  152  may be placed at the center, while gas is supplied by the gas supply system  96  and vacuum-exhausted by the vacuum exhaust system  94 .  
      The middle transfer chamber  72  is provided with a middle transfer arm device  108  disposed therein, which is formed of an articulated arm device that can extend, contract, and rotate, and has one pick. The arm device  108  may have a plurality of, e.g., two, picks, so that it can handle a plurality of wafers at a time. An additional processing apparatus  110  (see  FIG. 2 ) is connected to the sidewall of the middle transfer chamber  72  through a gate valve G 1 . The additional processing apparatus  110  is also provided with a gas supply system  111  and a vacuum exhaust system  113  in accordance a process to be performed. The additional processing apparatus  110  is set to perform a predetermined vacuum atmosphere process, such as cooling of a processed wafer, film thickness measurement of measuring a film thickness on a wafer, or particle measurement of measuring particles on a wafer, or an additional degas function, as needed.  
      As shown in  FIG. 3 , a wafer holder  116  is disposed in the second buffer chamber  74 . The wafer holder  116  includes a base  112  and three struts standing thereon. The three struts have a plurality of, e.g., two wafer support grooves, so that it can support two wafers W at most at a time. The base  112  can rotate and move up and down by an elevating and rotating shaft  118 , which airtightly penetrates the bottom of the second buffer chamber  74 . The wafer holder  116  is arranged to hold two wafers, but the number of which does not set a limit thereto. The wafer holder  116  may be arranged to hold more that two wafers, or one wafer.  
      The base  112  of the wafer holder  116  is rotated to cause the notch or orientation flat of a wafer W to face in a predetermined direction relative to the arm device  46  disposed in the common transfer chamber  36 . For example, where the vacuum processing apparatus  34 A and the additional processing apparatus  110  on the left side in  FIG. 1  are the same type of apparatus, the notch or orientation flat of a wafer W needs to be positioned at the same specific position (for example, a position on the transfer port side) in the apparatuses  34 A and  110 . In this case, if a wafer W is taken out of the apparatus  110  and only placed in the second buffer chamber  74  by the arm device  108  disposed in the middle transfer chamber  72 , the notch or orientation flat of the wafer W is positioned on the side reverse to the side required by the apparatus  34 A when the wafer W is transferred by the arm device  46  disposed in the common transfer chamber  36 . The base  112  of the wafer holder  116  is rotated to solve this problem.  
      The second buffer chamber  74  may be provided with a vacuum exhaust system  94  and a gas supply system  96 , as in the first buffer chamber  70 . The entire arrangement described above is common to both of the transfer passages  38 A and  38 B.  
      An explanation will be give of an operation of the arrangement described above, according to this embodiment.  
      Prior to a process, the interior of the front side relative to the two first buffer chambers  70 , i.e., of the entrance transfer chamber  32 , in this example, is kept at atmospheric pressure (normal pressure). On the other hand, the deeper side relative to the two first buffer chambers  70 , i.e., the two middle transfer chambers  72 , two second buffer chambers  74 , and common transfer chamber  36  communicate with each other and are kept at a vacuum atmosphere.  
      First, an unprocessed semiconductor wafer W is picked up by the arm device  58  disposed in the entrance transfer chamber  32 , from a cassette container C placed on the table  52  in one of the three loading ports  54 .  
      Then, the wafer W is transferred by the arm device  58  to the orientor  66 , which then performs alignment of the wafer W.  
      Then, the wafer W aligned by the transfer arm device  58  is transferred into the first buffer chamber  70  of one of the two transfer passages  38 A and  38 B. In the first buffer chamber  70 , the wafer W is held on the upper switching lid  136  of the pre-heating mechanism  120 .  
      As described above, the first buffer chamber  70  has a load-lock function, degas function, and cooling function. The interior of the first buffer chamber  70  is vacuum-exhausted to a predetermined pressure by the vacuum exhaust system  94 , in a state where the gate valves  78  on both sides of the first buffer chamber  70  accommodating the wafer W are airtightly closed. Then, the wafer W is heated by the heating lamp  134  or heating means, to perform a degas process.  
      After the degas process is performed for a predetermined time, as described above, and pressure adjustment is performed, the gate valve  78  on the middle transfer chamber  72  side is opened. The degas-processed wafer W is then transferred by the middle transfer arm device  108  from the first buffer chamber  70  onto the wafer holder  116  disposed in the second buffer chamber  74 . The wafer holder  116  is rotated by a predetermined angle for angle adjustment, so that the notch or orientation flat of the wafer is directed to a predetermined direction for the next transfer.  
      Then, the wafer W is transferred by the common transfer arm device  46  disposed in the common transfer chamber  36 , from the wafer holder  116  into a predetermined one of the four vacuum processing apparatuses  34 A to  34 D. Then, the wafer W is subjected to predetermined vacuum processes respectively in the vacuum processing apparatuses  34 A to  34 D. As regards these vacuum processes, the wafer W is sequentially transferred among the processing apparatuses  34 A to  34 D to receive different vacuum processes, as needed.  
      After all the vacuum processes on the wafer W are completed, as described above, the wafer W is transferred out though a course reverse to that described above. In this course, the wafer W is returned back to the middle transfer chamber  72 , and transferred into the additional processing apparatus  110 . The additional processing apparatus  110  is used to perform film thickness measurement, particle measurement, or the like, depending on the apparatus type. After the process or measurement on the wafer W is completed, the wafer W is transferred into the middle transfer chamber  72  again. Then, the wafer W is transferred into the first buffer chamber  70 , which has been vacuum-exhausted to have a vacuum state, and is held on the support pins  162  on the lower switching lid  15  of the cooling mechanism  122 . The wafer is cooled to a predetermined temperature by a cooling gas in the first buffer chamber  70 , while maintaining an airtight state. After the cooling, pressure adjustment is performed here, and the wafer W is transferred through the entrance transfer chamber  32  to, e.g., the original cassette container C.  
      There is a case where the functions of the intermediate structures  37 A and  37 B including the transfer passages  38 A and  38 B need to be changed, after the processing system is installed in a factory. For example, the first buffer chamber  70  may need to be used as a simple passage with no degas function, or the additional processing apparatus  110  may need to be used for performing a process at an atmospheric pressure (normal pressure) atmosphere, such as wet washing or degassing, instead of a vacuum atmosphere process.  
      The conventional semiconductor processing system is designed without taking into consideration the need for a variable system structure, resulting in a unit structure in which almost all the parts are unchangeable. Accordingly, the requirement described above cannot be satisfied.  
      On the other hand, according to the semiconductor processing system shown in  FIG. 1 , the first and second buffer chambers  70  and  74 , and the additional processing apparatus  110  are prepared as a module, as described above. These members  70 ,  74 , and  110  are detachably connected to each other through the gate valve  78  and the sleeve pipe  80  with no valve function. The modules can be detached by unfastening the connection bolts  90  of the flanges, if another module needs to be combined therein. The gate valves  78  are at least disposed one on either side of a buffer chamber arranged to have a load-lock function for repeating vacuum-exhaust and return to atmospheric pressure in accordance with wafer transfer.  
       FIG. 7  is a schematic plan view showing another state of the processing system of  FIG. 1 , obtained by changing some modules.  FIG. 8  is a plan view of the state of the processing system shown in  FIG. 7 .  FIG. 9  is an enlarged sectional view taken along line IX-IX in  FIG. 8 .  
      This processing system  30 A includes two second buffer chambers  74  set to be load-lock chambers. Each second buffer chamber  74  is connected to the adjacent chambers (the middle transfer chamber  72  and common transfer chamber  36 ) on both sides respectively through gate valves  78 (see  FIG. 4 ) in place of sleeve pipes  80  having no valve function (see  FIG. 5 ). A vacuum exhaust system  94  and a gas supply system  96  are connected to the second buffer chamber  74 , as in the first buffer chamber  70  shown in  FIG. 2 , so that the chamber  74  can be vacuum-exhausted. If the second buffer chamber  74  is provided with the vacuum exhaust system  94  and gas supply system  96  in advance, this module of the second buffer chamber  74  does not need to be replaced, and only requires the sleeve pipes  80  on both sides to be replaced with the gate valves  78 .  
      The processing system in the state shown in  FIG. 7  includes additional processing apparatuses  110 A, each of which performs an atmospheric pressure atmosphere process, such as a degas process or wet washing process, as described above, instead of a vacuum atmosphere process. Accordingly, in the processing system  30 A, each first buffer chamber  70  is provided with sleeve pipes  80  having no valve function on both sides, in place of gate valves  78 . In the first buffer chamber  70 , the support pins  142  on the upper switching lid  136  or the support pins  162  on the lower switching lid  152  are used only for temporarily holding a wafer W.  
      A module having an inner structure the same as that of the second buffer chamber  74  may be used as the first buffer chamber  70 . Similarly, a module having an inner structure the same as that of the first buffer chamber  70  may be used as the second buffer chamber  74 . In this case the second buffer chamber  74  has a cooling function or degas function.  
      In the processing system  30 A, the entrance transfer chamber  32 , two first buffer chambers  70 , and two middle transfer chambers  72  always have an atmospheric pressure atmosphere therein. On the other than, the common transfer chamber  36  always has a vacuum atmosphere therein.  
      The processing system  30 A may be modified, such that each middle transfer chamber  72  is provided with an inactive gas supply system and a vacuum exhaust system to keep its interior at an atmospheric pressure atmosphere with an inactive gas, such as N2 gas or Ar gas. In this case, gas replacement with N2 gas or Ar gas can be performed in each first buffer chamber  70 , if it is provided with gate valves  78  on both sides, and also provided with an inactive gas supply system and a vacuum exhaust system.  
      In the states shown in  FIGS. 1 and 7 , the two intermediate structures  37 A and  37 B have interfaces between an atmospheric pressure atmosphere and a vacuum atmosphere, set at the same position. The two intermediate structures  37 A and  37 B may have interfaces between an atmospheric pressure atmosphere and a vacuum atmosphere, set at different positions.  
       FIG. 10  is a schematic plan view showing still another state of the processing system of  FIG. 1 , obtained by changing some modules. In the state shown in  FIG. 10 , the intermediate structure  37 A employs an additional processing apparatus  110  with a vacuum atmosphere, and thus includes a first buffer chamber  70  set to be a load-lock chamber. On the other hand, the intermediate structure  37 B employs an additional processing apparatus  110 A with an atmospheric pressure atmosphere, and thus includes a second buffer chamber  74  set to be a load-lock chamber.  
      Accordingly, as shown in  FIGS. 1, 7 , and  10 , each of the intermediate structures  37 A and  37 B is selectively arranged to be in either of the following first and second states. In the first state, the additional processing apparatus  110  is set to perform a predetermined process on a wafer W within a vacuum atmosphere, while the first buffer chamber  70  is set to be a load-lock chamber for adjusting pressure between atmospheric pressure and vacuum. In the second state, the additional processing apparatus  110 A is set to perform a predetermined process on a wafer W within an atmospheric pressure atmosphere, while the second buffer chamber  74  is set to be a load-lock chamber for adjusting pressure between atmospheric pressure and vacuum.  
      In the states shown in  FIGS. 1, 7 , and  10 , any one of the first and second buffer chambers  70  and  74 , which is not set to be a load-lock chamber, is connected to the adjacent chambers on both sides respectively through sleeve pipes  80  having no valve function. However, the chamber that is not set to be a load-lock chamber, of the first and second buffer chambers  70  and  74 , may be connected to the adjacent chambers on both sides respectively through gate valves  78 . In this case, the gate valves  78  of the chamber not set to be a load-lock chamber can be kept always open, under the control of software.  
      In a semiconductor processing system according to′, this embodiment of the present invention, each of the transfer passages  38 A and  38 B is formed of the first and second buffer chambers  70  and  74 , and middle transfer chamber  72 , which are prepared as modules and detachably connected to each other by gate valves  78  or sleeve pipes  80 . Accordingly, after the processing system is installed in a factory, or when the processing system is manufactured before shipping, the system can comply with various applications. When the system application is changed, the buffer chambers are replaced with buffer chambers having other functions, while detaching the corresponding gate valves  78  or sleeve pipe  80 . An area for maintaining a vacuum atmosphere can be easily and selectively changed by replacing the gate valves  78  with the sleeve pipes  80 , and vice versa. Since each module can be easily attached and detached, maintenance thereof can be simplified.  
      The common transfer chamber  36  of the system shown in  FIGS. 1, 7 , and  10  has an almost hexagonal shape, but it may have a rectangular, pentangular, heptangular, or higher order polygonal shape.  FIG. 11  is a schematic plan view showing a semiconductor processing system according to another embodiment of the present invention, which has a pentangular common transfer chamber. In the system shown in  FIG. 11 , two second buffer chambers  74  are connected to one side of the common transfer chamber  36 .  
      The system shown in  FIGS. 1, 7 , and  10  has the two intermediate structures  37 A and  37 B respectively defining the transfer passages  38 A and  38 B. However, the entrance transfer chamber  32  and common transfer chamber  36  may be connected only by an intermediate structure of one route, or by intermediate structures of three or more routes.  
       FIG. 12  is a schematic plan view showing a semiconductor processing system according to still another embodiment of the present invention. The system shown in  FIG. 12  includes one route of a transfer passage formed of a first buffer chamber  70  and a middle transfer chamber  72 , connected to an entrance transfer chamber  32 . One or more processing apparatuses  34 A and  34 B are connected to the middle transfer chamber  72 . As a result, a system arrangement is realized, similar to that disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2000-208589.  
       FIG. 13  is a schematic plan view showing a semiconductor processing system according to still another embodiment of the present invention. The system shown in  FIG. 13  includes a plurality of, two in this illustrated example, independent routes, each of which is a transfer passage formed of a first buffer chamber  70  and a middle transfer chamber  72 , connected to an entrance transfer chamber  32 . One or more processing apparatuses  34 A and  34 B are connected to each middle transfer chamber  72 .  
      In the system shown in  FIG. 13 , the processing apparatuses  34 B and  34 C are connected to the middle transfer chamber  72  respectively through sleeve pipes (adapter)  180  having no valve function. Where the processing apparatuses  34 B and  34 C are large, they cannot be disposed without the sleeve pipes  180  that can change the connecting direction of the processing apparatuses relative to the middle transfer chamber  72 . Each sleeve pipe  180  has the same structure as that of the sleeve pipe  80  show in  FIG. 5  except that one attaching surface is inclined relative to the wafer transfer direction.  
      In the embodiments, a semiconductor wafer W is described as a target substrate. The present invention is not limited to this, and may be applied to a glass substrate or LCD substrate.