Abstract:
A vacuum processing apparatus includes a vacuum processing chamber having a processing table for supporting an object to be processed and carrying out processing using a gas. The vacuum processing chamber has an axisymmetric structure, including a double wall structure, and a gate valve for sealing an opening through which the object enters the processing chamber.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a vacuum processing apparatus for treating an object inside a decompressed apparatus, and especially relates to a vacuum processing apparatus for processing a semiconductor substrate (wafer) using plasma generated within the apparatus.  
       DESCRIPTION OF THE RELATED ART  
       [0002]     In the field of vacuum processing apparatuses, especially vacuum processing apparatuses for treating objects within a decompressed chamber, there are increasing demands for enhancing the preciseness of microfabrication of the processes and for improving the efficiency for processing the object wafer. Thus, in recent years, a multiple chamber-type vacuum processing apparatus has been developed in which multiple processing chambers are connected to a single transfer unit, allowing various processes to be performed to the object wafer within a single vacuum processing chamber and there by improving process efficiency.  
         [0003]     According to the vacuum processing apparatus comprising multiple processing chambers for carrying out various processes, each processing chamber is connected to a transfer chamber (transfer unit) capable of having its inner pressure decompressed or having appropriate gases introduced thereto and equipped with a robot arm or the like for transferring wafers.  
         [0004]     According to such arrangement, the wafer either before or after being subjected to processing is transferred from one processing chamber to another processing chamber via a transfer chamber having decompressed pressure or having inert gas introduced thereto, so the wafer can be subjected to multiple processes continuously without being exposed to outside air. Thus, contamination of the wafer is suppressed, and the yield and the efficiency of the processes are thereby improved.  
         [0005]     Moreover, since the time required for increasing and decreasing the pressure within the processing chamber and the transfer chamber can be cut down or even eliminated, the number of steps required for processing is reduced, the time and work required for the overall processing of the wafer is cut down, and the process efficiency is improved.  
         [0006]     According to such vacuum processing apparatuses, the multiple processing chambers can be detached independently from the transfer chamber, so that the apparatus can be prepared to correspond to new processes by rearranging the processing chambers and the components thereof without having to replace the whole apparatus body. As a result, the cost for manufacturing products using the vacuum processing apparatus is cut down.  
         [0007]     A conventionally known vacuum processing apparatus in which processing chambers are detachably attached is disclosed for example in patent document 1 (Japanese Patent Laid-Open Publication No. 6-267808), in which various processing chambers for treating a semiconductor wafer are connected detachably onto a wafer transfer chamber, a transfer stage capable of moving in the X, Y or Z-axis direction is disposed below each of the processing chambers, and the position in which each processing chamber is mounted to the wafer transfer chamber is adjusted by the movement of the stage. The construction of such prior art apparatus facilitates the positioning of each processing chamber with respect to the transfer chamber, and simplifies the operation for attaching and detaching the chambers.  
         [0008]     However, the prior art apparatus suffered the following drawbacks. When multiple processing chambers are disposed adjacent one another, the size of each unit attached to or detached from the apparatus becomes large due to the guiding mechanism including the transfer stage disposed to the lower portion of the apparatus, and therefore, the footprint of the whole vacuum processing apparatus is enlarged. Consequently, the number of apparatus that can be installed in a certain area, for example, a clean room, is reduced, and the fabrication efficiency of products manufactured by operating a plurality of apparatuses is thus deteriorated. However, there were no considerations related to overcoming this problem in the prior art.  
         [0009]     It may be possible to reduce the footprint of the apparatus by miniaturizing the guiding mechanism, by which the spaces interposed between the multiple processing chambers are minimized. However, this causes another drawback in that the space for carrying out maintenance operations or connecting and disconnecting of processing chambers is reduced, which leads to deterioration of the operation efficiency and longer work time, increase of non-operation time during which the operation of the apparatus is stopped, deterioration of operation efficiency of the vacuum processing apparatus, and increase of manufacturing costs.  
         [0010]     Moreover, there were considerations in the prior art related to facilitating the connection of the processing chambers with the transfer chamber, but there were no considerations on facilitating the connection and disconnection of various apparatuses used in the processing chamber, such as the supply and exhaust mechanisms of processing gas and air, or supply mechanisms of power and refrigerant. In other words, according to the prior art, there were no considerations on improving the operation efficiency upon attaching and detaching processing chambers other than facilitating the positioning thereof, and as a result, long work time was required and the operation efficiency of the vacuum processing apparatus was deteriorated.  
         [0011]     Furthermore, the prior art lacks consideration on how to realize a predetermined performance in each processing chamber in a stable manner after attaching the chamber to the apparatus. That is, after attaching a processing chamber that has a different construction from the processing chamber attached previously, each processing chamber being newly attached must be subjected to an adjustment procedure after attachment so as to realize determined performance, according to which the time required after attachment and detachment or during maintenance is extended, and thus the operation efficiency of the vacuum processing apparatus is deteriorated.  
         [0012]     Even further, according to the above-mentioned prior art apparatus, when one processing chamber is subjected to maintenance or being attached or detached, the other processing chambers connected to the wafer transfer chamber cannot perform processing. Thus, during maintenance or attachment and detachment of a certain processing chamber, the whole vacuum processing apparatus stops operating even though other processing chambers are prepared for processing. Therefore, the operation efficiency of the vacuum processing apparatus is significantly deteriorated, but the prior art lacks to provide any measures against this problem.  
         [0013]     Moreover, upon carrying out maintenance and other operation of the interior of the processing chamber, the pressure within the chamber must be substantially equalized with the ambient pressure, and after completing the operation, the processing chamber must be decompressed for processing. If the time required for increasing and decreasing pressure in the processing chamber is long, then the time for carrying out the processing in the chamber is relatively reduced, so the operation efficiency of the vacuum processing chamber is deteriorated and the fabrication cost of the product is increased. The prior art also lacks to consider this problem.  
       SUMMARY OF THE INVENTION  
       [0014]     The object of the present invention is to provide a vacuum processing apparatus that is small in size with a small footprint.  
         [0015]     Another object of the present invention is to provide a vacuum processing apparatus in which the operations related to maintenance and the connecting or disconnecting of components are facilitated.  
         [0016]     Yet another object of the present invention is to provide a vacuum processing apparatus having an improved operation efficiency.  
         [0017]     In order to solve the above-mentioned problems of the prior art, the present invention provides a vacuum processing apparatus comprising a transfer unit disposed at a center thereof; plural processing chambers, each processing chamber having a processing table for supporting an object to be processed and carrying out processing using a gas; and a mass flow controller interposed between two processing chambers for supplying gas to the chambers.  
         [0018]     Furthermore, the present invention provides a vacuum processing apparatus comprising plural processing chambers, each processing chamber having a processing table for supporting an object to be processed and carrying out processing using a gas in plasma state; and a high frequency power source used for turning the gas into plasma.  
         [0019]     The present invention further provides a vacuum processing apparatus comprising plural processing chambers, each processing chamber having a processing table for supporting an object to be processed and carrying out processing using a gas, wherein a connector portion between the vacuum processing apparatus and a building in which the apparatus is installed for supplying from the building utilities such as gas, water and air to the vacuum processing apparatus and discharging exhaust and the like from the apparatus is disposed in a line under an entry port for transferring the object into vacuum.  
         [0020]     The present invention further provides a vacuum processing apparatus comprising a vacuum processing chamber having a processing table for supporting an object to be processed and carrying out processing using a gas, the vacuum processing chamber having an axisymmetric structure, wherein the vacuum processing chamber has a double wall structure and comprises a gate valve for sealing an opening through which the object enters the processing chamber.  
         [0021]     Moreover, the present invention provides a vacuum processing apparatus comprising a vacuum processing chamber having a processing table for supporting an object to be processed and carrying out processing using a gas, the vacuum processing chamber having an axisymmetric structure with respect to the object to be processed, wherein the vacuum processing chamber has a double wall structure and comprises a gate valve for sealing an opening formed to the chamber wall through which the object enters the processing chamber; and the shape of the gate valve for sealing the opening formed to the inner vacuum processing chamber wall is determined so that it does not interfere with the axisymmetric structure of the vacuum processing chamber.  
         [0022]     The present invention further provides a vacuum processing apparatus comprising a vacuum processing chamber having a processing table for supporting an object to be processed and carrying out processing using a gas, the vacuum processing chamber having an axisymmetric structure with respect to the object to be processed, wherein the vacuum processing chamber has a double wall structure and comprises a gate valve for sealing an opening formed to the chamber wall through which the object enters the processing chamber; and an inner vacuum processing chamber has a wall divided into two portions, an upper portion and a lower portion, with the processing table interposed between the two portions. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]      FIG. 1  is a perspective view showing the overall structure of a vacuum processing apparatus according to the preferred embodiment of the present invention;  
         [0024]      FIG. 2  is a plan view showing the outline structure of the vacuum processing apparatus according to the embodiment of the present invention;  
         [0025]      FIG. 3  is a perspective view showing the outline structure of each unit of the vacuum processing apparatus according to the embodiment of the present invention;  
         [0026]      FIG. 4  is a side view showing the positional relationship between the control unit and each processing units according to the embodiment of  FIG. 1 ;  
         [0027]      FIG. 5  is a vertical cross-sectional view showing the outline structure of the processing chamber in the processing unit according to the embodiment of  FIG. 1 ;  
         [0028]      FIG. 6  is a horizontal cross-sectional view showing the outline structure of the processing chamber illustrated in  FIG. 5 ;  
         [0029]      FIG. 7  is a vertical cross-sectional view explaining the removal of components from the processing chamber illustrated in  FIG. 5 ; and  
         [0030]      FIG. 8  is a vertical cross-sectional view explaining the removal of components from the processing chamber illustrated in  FIG. 5 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0031]     The preferred embodiment of the present invention will now be explained in detail with reference to the accompanying drawings.  
         [0032]      FIG. 1  is a perspective view showing the overall structure of a vacuum processing apparatus according to a preferred embodiment of the present invention.  FIG. 1 ( a ) is a perspective showing the front side, and (b) is a perspective showing the back side thereof. In this drawing, a vacuum processing apparatus  100  according to the present embodiment is largely divided into two, front and back, blocks. The front side of the vacuum processing apparatus body  100  is an atmospheric block  101  in which a wafer supplied to the apparatus is transferred to a chamber decompressed under atmospheric pressure and supplied to a processing chamber. The rear side of the apparatus body  100  is composed of a processing block  102 . The processing block  102  comprises processing units  103  and  104  having processing chambers being decompressed for processing wafers, a transfer unit  105  for transferring wafers to these processing chambers under reduced pressure, and plural lock chamber units  113  for connecting the transfer unit  105  with the atmospheric block  101 , these units capable of being decompressed and maintained at high degree of vacuum, so the processing block is a vacuum block.  
         [0033]     The atmospheric block  101  comprises a box  108  having a transfer robot (not shown) disposed within, a wafer cassette  109  in which wafers for processing or cleaning are stored and a dummy cassette  110  storing dummy wafers disposed on the box  108 . The transfer robot transfers wafers stored in these cassettes  109 ,  110  to a lock chamber unit  113 , and vice versa. The atmospheric block  101  further comprises a positioning unit  111  disposed on the box  108 , and within this positioning unit  111 , the transferred wafer is adjusted of its position appropriately for the wafer location in the cassette  109  or  110 , or in the lock chamber unit  113 .  
         [0034]     As for the processing units  103  and  104  in the processing block  102 , the processing unit  103  is an etching unit equipped with an etching chamber for etching the wafer transferred into the processing block from the cassette  109 , and the processing unit  104  is an ashing unit for providing an ashing treatment to the wafer transferred thereto. The transfer unit is equipped with a transfer chamber  112  capable of being decompressed to high degree of vacuum and maintaining the vacuum state, and to which the processing units  103  and  104  are detachably connected. Further, the processing block  102  comprises a control unit  107  including a mass flow controller for controlling the feeding of gas and fluid required in the units or processing chambers, the control unit  107  disposed between and adjacent to the processing units  103  and  104 .  
         [0035]     At the lower area of the processing block  102  is disposed a frame  106  storing a rectangular bed for storing necessary utilities corresponding to each of the processing units such as storage and exhaust units of gases and refrigerants or power sources for feeding power. The processing chamber portion of the processing units  103 ,  104 , the control units  107  and the bed are detachably disposed on the frame  106 .  
         [0036]      FIG. 2  is a view showing the outline of the structure of the vacuum processing chamber  100  according to the embodiment of  FIG. 1 , in which  FIG. 2 ( a ) shows a plan view from above, and  FIG. 2 ( b ) shows the view from the side. In these drawings, the atmospheric block  101  disposed on the front side of the vacuum processing apparatus body  100  is for handling (transferring, storing, positioning etc.) the wafers under atmospheric pressure, and the processing block  102  disposed on the rear side of the apparatus body  100  is for transferring and processing wafers under a pressure decompressed from atmospheric pressure and for increasing and decreasing pressure while wafers are disposed therein.  
         [0037]     Each lock chamber unit  113  connects the atmospheric block  101  with the transfer chamber  112  of the transfer unit  105 , the chamber  113  having connected thereto a gas exhaust unit and a gas supply unit for increasing and decreasing the inner pressure of the lock chamber  113  having disposed in its interior the transferred wafer, and for maintaining a controlled pressure. Thus, the lock chamber unit  113  is equipped with gate valves disposed on its front and rear ends that can be opened and closed, enabling the lock chamber to be sealed in airtight manner. The lock chamber unit  113  further comprises a wafer holder for supporting a wafer, and a means for fixing the wafer to position during increase and decrease of inner pressure of the chamber. In other words, the lock chamber unit  113  is equipped with means for sealing the chamber while a wafer is disposed therein, the sealing means capable of bearing the pressure difference between the inside and outside of the chamber.  
         [0038]     As explained, the transfer unit  105  is composed of a transfer chamber  112  with reduced inner pressure and having a robot arm (not shown) disposed therein for transferring wafers between processing chambers  103 ,  104  and the lock chamber unit  113 , and multiple lock chambers  113 .  
         [0039]     According to the present embodiment, as for processing units  103  and  104 , two etching units and two ashing units are respectively connected to and disposed on each side of a polygonal transfer chamber  112  of the transfer unit  105 , in which two etching units  103  are disposed on two sides of the transfer chamber  112 , and two ashing units  104  are each disposed on the side adjacent to the etching units  103 . Lock chamber units  113  are connected to the remaining sides of the transfer chamber. In other words, the present embodiment comprises two etching chambers and two ashing chambers.  
         [0040]     According further to the present embodiment, the processing units  103  and  104  are connected to the transfer unit  105  in a detachable manner, and the lock chamber units  113  and the transfer chamber  112  are also detachably disposed in the transfer unit  105 . Each of the processing units  103  and  104  can be conceptually divided into upper and lower areas, the upper area being the chamber portion containing the processing chamber, and the lower area being the bed portion storing utilities corresponding to the specific processing chamber.  
         [0041]     The bed portion is a substantially rectangular body storing utilities, a controller, a heat exchanger etc. required for the chamber unit located above. Examples of utilities include an air pump for reducing the pressure of the processing chamber, a power source for supplying power, a gas storage portion for feeding gas to a wafer holder having a wafer (sample) mounted thereon and fixed thereto in the processing chamber, a refrigerant storage for cooling the wafer holder, and a heat exchanger of a refrigeration cycle for performing heat exchange of the refrigerant and cycling the same. The bed stores these utilities, the bed being stored in and connected to the frame  106  disposed below the chamber unit. A side of one rectangular bed faces to a side of another rectangular bed next to it. Beds for four processing units, in this embodiment, are composed and disposed shaping a substantially large rectangle. A width of the large rectangle is not larger than a width of the box  108  of the atmospheric block.  
         [0042]     The chamber unit is connected to the corresponding sides of the transfer chamber  112  via a predetermined connecting gate. Furthermore, the bed unit corresponding to the chamber unit is stored in the frame  106  disposed under the transfer chamber  112  and connected to the vacuum chamber apparatus body  100 . The frame  106  further stores an interface unit required for driving the various utilities stored in the bed.  
         [0043]     According to the present embodiment, a combination of a processing chamber unit and a corresponding bed unit constitutes one processing unit. A single processing unit is connected as one unity to the apparatus body  100  or the transfer unit  105  (transfer chamber  112 ) in a detachable fashion. Within a single processing unit, the processing chamber can be connected to the transfer unit  105  while the corresponding bed portion is attached thereto or detached therefrom, and conversely, the bed portion can be connected to the frame  106  while the upper processing chamber can be attached thereto or removed therefrom.  
         [0044]     At the rear side of the atmospheric block  101  in the space interposed between the processing block  102  are disposed lock chamber units  113 , and a gap is formed between the rear side and the frame  106  or between each bed. The rear side surface of the atmospheric block  101  is used as a supply route for supplying gas, refrigerant, power etc. to the processing block. The present vacuum processing apparatus  100  is typically disposed inside a room with purified air, such as a clean room, but when plural apparatuses are to be disposed, generally the sources for various gases, refrigerants and power to be supplied to the apparatus bodies  100  are disposed on a different floor from where the apparatuses are installed, and fed to each apparatus via pipes. In the present embodiment, a connection interface  201  for connecting supply lines such as pipes for gases and refrigerants from separate locations or lines from the power sources is disposed on the rear side portion of the atmospheric block. In other words, a connector portion between the vacuum processing apparatus and the building in which the apparatus is installed for supplying from the building utilities such as gas, water and air to the apparatus and discharging exhaust from the apparatus is disposed substantially linearly under an entry port for transferring the wafer into vacuum.  
         [0045]     The supply routes for various utilities being connected via the connection interface unit  201  to the supply path and extending to the processing block  102 , that is, the supply lines of pipes and power lines extending from the connection interface unit  201 , pass below the lock chamber unit  113  and below the center area of the transfer chamber  112 , and via an interface unit disposed on the frame  106  and connected to each of the beds.  
         [0046]     According to the prior art apparatuses, the pipes and power lines from a supply source disposed on a separate floor were introduced separately to the processing chambers, so the connecting and disconnecting of the pipes etc. during maintenance of the processing chamber or during replacement of apparatuses required complicated work, and the work efficiency was deteriorated. Further, display means such as meters for displaying the status of flow of the pipes and power lines and means for controlling the same were provided to each of the processing chambers, so it was not easy for the operator to check the operation status of the apparatuses. Moreover, since these pipes were disposed surrounding the processing chambers, the footprint of the overall apparatus was substantially increased thereby, and the number of apparatuses that can be disposed on one floor was reduced, or the space for carrying out maintenance and other operations was reduced and the work efficiency was deteriorated.  
         [0047]     According to the present embodiment, the prior art problems are solved according to the above-explained arrangement in which sufficient work space is secured, operation status is easily confirmed, and footprint of the apparatus is cut down. On the rear side of the box  108  is disposed a display unit  202  comprising a sensor for detecting the status of each supply line connected to the connection interface  201  and extending toward the processing block  102  and display means for displaying the result of sensor output so that the user can confirm the operation status of the apparatus easily. Further, it is possible to dispose a control means for controlling the supply through each supply line or to enter an order to control the same.  
         [0048]     A gap is formed between the rear surface of the box  108  and the fame  106  of the processing block  102 , this gap providing a space in which a user can enter and work on the processing units  104 , the transfer chamber  112  and the lock chamber  113 , and also providing a space in which the user can confirm the display  202  on the rear of the box  108  and the connection interface unit  201  or enter orders via the control means etc. Further, means for controlling and displaying information on the operation of apparatuses related to the supply lines are collectively disposed in this space. Thus, the work related to operating the apparatus is facilitated, and the operation efficiency of the apparatus is improved.  
         [0049]     Moreover, according to the present embodiment, the supply lines for supplying utilities required in units of the processing block  102  are disposed collectively. By disposing the power lines and pipes extending from a different floor, such as one floor below the floor on which the apparatus is installed, on the rear surface of the box  108  collectively, the work related to the attaching, connecting and removing of supply lines during installation of the apparatus body  100 , maintenance operation of the apparatus or the replacement of equipments is facilitated, and the work efficiency is thereby improved.  
         [0050]     Furthermore, according to the present embodiment, the supply lines such as power lines and pipes from the connection interface unit  201  is extended below the lock chamber  113  and the center area of the transfer chamber  112 , and via an interface unit disposed on the frame  106  to each bed, but the supply lines such as the pipes and power lines from the connection interface unit  201  can be connected directly to the equipments stored in the bed of the frame  106 .  
         [0051]     Moreover, a supply path  203  from the connection interface unit  201  is disposed so as to extend from the rear side of the atmospheric block  101  and below the lock chamber unit  113  and the transfer chamber  112 . Especially, the supply path  203  is collectively passed through the space formed between the beds under the transfer chamber  112 , and connected to each bed or frame  106 . In other words, the space formed by plural units surrounding the transfer chamber  112  and in which the supply path  203  is disposed is placed at the inner side or center area of the apparatus.  
         [0052]     This space for disposing the supply path is located below the transfer chamber  112  and lock chamber unit  113 , and interposed between the beds of the processing units. Thus, space for mounting, connecting or disconnecting the supply path  203  can be secured, the work related thereto is facilitated and the work efficiency improved, so as a result, the overall operation efficiency of the apparatus is improved.  
         [0053]     Further, since the connecting portions of the utilities are disposed in the inner side of the apparatus, that is, in the space below the transfer chamber  112  and interposed between beds, the space required for working on the connecting portions is minimized, the footprint of the apparatus system is reduced compared to the case in which supply lines and connectors are disposed around the apparatus, and the number of apparatuses that can be installed in one unit floor area is increased.  
         [0054]      FIG. 3  is a perspective view showing the outline of the structure of each unit.  FIG. 3 ( a ) illustrates the combined status of the processing units. On the other hand, FIGS.  3 ( b ), (c) and (d) illustrate the units separately.  FIG. 3 ( b ) shows the etching unit  103 ,  FIG. 3 ( c ) shows the ashing unit  104 , and  FIG. 3 ( d ) shows the control unit including a MFC (mass flow controller).  
         [0055]     As illustrated, the processing units  103  and  104  respectively comprise a processing unit  103   a  or  104   a  in the upper area and a bed portion  103   b  or  104   b  in the lower area stored in and connected to a frame  106 . In the space formed between the processing portion  103   a  and the bed  103   b  of the etching unit  103  are disposed pipes and lines communicated between  103   a  and  103   b  through which gases, cycled refrigerant and power are supplied, and the processing unit  103   a  is supported above the bed portion  103   b  by plural support beams not illustrated disposed on the frame  106 . Similarly, in the space formed between the processing portion  104   a  and the bed portion  104   b  of the ashing unit  104  are disposed pipes and lines communicated between  104   a  and  104   b  through which gases, cycled refrigerant and power are supplied, and the processing unit  104   a  is supported above the bed portion  104   b  by plural support beams not illustrated disposed on the frame  106 .  
         [0056]     As illustrated, the control unit  107  is disposed between the etching unit  103  and the ashing unit  104 , and mounted on the frame  106  above the bed units  103   b  and  104   b  of these units. The control unit  107  is for controlling the supply of necessary gases etc. to the processing units located adjacent thereto. For example, a flow controller disposed inside the control unit  107  controls the flow of gas or supply of power to the processing chamber disposed inside the processing unit  103   a  of the etching unit  103 .  
         [0057]      FIG. 4  is a side elevational view showing the locational relationship of the control unit  107  and the processing units according to the embodiment of  FIG. 1 . The control unit  107  is located between the etching unit  103  and ashing unit  104 . Inside the control unit  107  is disposed a controller (for example, MFC) for controlling the supply of gases etc. to the processing units.  
         [0058]     In the present embodiment, plural flow controllers are disposed within the control unit  107  for controlling the amount and rate of flow of processing gases to be supplied to the etching unit  103  and the ashing unit  104  and the gas or refrigerant used for controlling the temperature of the wafer or wafer holder within the chamber. Especially, the flow controller for the etching unit is disposed on the upper area and the flow controller for the ashing unit is disposed on the lower area within the control unit  107 . Upper and lower access doors  401  and  402  are disposed on the control unit  107  enabling access to the devices equipped within the control unit including these flow controllers, for maintenance and replacement of the devices.  
         [0059]     For example, storage units for gases and fluids (refrigerant, water etc.) to be supplied to the processing chambers, valves for controlling the flow of gases and fluids, and motors for driving the valves are stored in the control unit. Such controllers are prepared for each processing chamber. The reason for this is as follows. The processing units of the present embodiment are removably attached to the transfer chamber  112  or the vacuum processing apparatus body  100 , and a single apparatus  100  comprises multiple processing units capable of carrying out various processes for treating wafers. By preparing processing units having different specifications for carrying out different processes, and by replacing the processing units, a wide variety of processes can be carried out using a single apparatus. Independent control for each processing unit must preferably be implemented so as to realize the best process conditions and operation conditions of the apparatus in response to the various processing units having different specifications of processes such as different gases and different temperature being used.  
         [0060]     According to such a vacuum processing apparatus, the control unit  107  of the present embodiment is disposed between two processing units, and formed so that it can be easily connected to the units. Thus, the attaching and detaching of processing units or control units of the apparatus is facilitated, and the work time is cut down.  
         [0061]     The group of equipments corresponding to each processing unit is disposed vertically within the control unit  107 , reducing the required space for disposing equipments. The effective use of space interposed between processing units enables distance between processing units to be minimized and overall footprint of the apparatus to be cut down. It also enables the difference between lengths of fluid flow paths supplied to the processing chambers to be reduced. Thus, difference in flow path lengths to the processing chamber before and after replacement of the processing unit or processing chamber is suppressed.  
         [0062]     Thus, the present embodiment suppresses any difference in performance of the apparatus before and after replacement or maintenance of units, facilitating the user of the control to be performed via the control unit  107 , and improving the yield factor of the overall processing apparatus.  
         [0063]      FIG. 5  is a vertical cross-sectional view showing the outline of the structure of the processing chamber in the processing unit according to the embodiment of  FIG. 1 . FIG. 6  is a horizontal cross-sectional view of  FIG. 5 , taken at a horizontal plane at the gate portion.  FIGS. 5 and 6  especially illustrate the structure of the processing chamber of the etching unit  103 . In these drawings, the processing chamber portion  500  is connected to the transfer chamber  112 , and an atmospheric gate valve  514  disposed between the processing chamber  500  and the transfer chamber  112  opens or closes the communication path. With this atmospheric gate valve  514  opened, the space inside the transfer chamber  112  is communicated with the space inside the processing chamber  500  and the pressure of both spaces become substantially equal.  
         [0064]     While the atmospheric gate valve  514  is opened, the wafer is transferred from the transfer chamber  112  onto a wafer holder  504  disposed within the processing chamber. According to the present embodiment, after detecting and confirming that the wafer is mounted on the wafer holder  504 , the atmospheric gate valve  504  is closed to shut the communication of the processing chamber  500  and the transfer chamber  112 , thereby sealing the processing chamber to start the processing.  
         [0065]     When the processing chamber  500  is to be detached from the transfer chamber  112 , or when performing maintenance of the chamber  500 , the atmospheric gate valve  512  is closed and then the pressure inside the processing chamber  500  is increased to atmospheric pressure, before outer chambers  511  and  512  defining the vacuum container of the processing chamber  500  are opened and exposed to the atmosphere. In the embodiment, more than one chamber is disposed inside the outer chambers  511  and  512  that constitute the outer walls of the processing chamber  500 , creating a multiple chamber structure in which a chamber is disposed inside another chamber.  
         [0066]     According to the present embodiment, two chambers, an inner chamber and an outer chamber, are formed. The wafer holder  504  is disposed inside the inner chambers  509 ,  510 , and the processing of the wafer is performed inside the inner most chamber. In order for the wafer being the object of processing to be mounted on the wafer holder  504  within the inner chambers  509 ,  510 , a gate must be provided to the inner chamber  509  or inner chamber  510  through which the wafer is to be transferred. Further, a valve is required for opening and closing a communication path communicating the inside of the chamber with the outside space by opening or closing this gate in airtight manner.  
         [0067]     The present embodiment comprises an atmospheric gate valve  514  for opening or closing the gate disposed between the inside of the processing chamber  500  and the inside of the transfer chamber  112  so as to realize the communication of the two chambers or to close the communication path therebetween in airtight manner, and a process gate valve  513  for opening or closing a path communicating the inside and the outside of the inner chamber  509  so as to realize the communication therebetween or to close the communication path in airtight manner. The atmospheric gate valve  514  is disposed on the side wall within a transfer chamber  112  and capable of being moved both in the vertical and horizontal directions by a drive means  522 , thereby either opening or shutting and sealing a gate on the inner side wall.  
         [0068]     Further, a gate is disposed on the exterior chamber  511  constituting the vacuum container, to the area corresponding to and communicating with the gate disposed on the transfer chamber  112  when the transfer chamber  112  and the processing chamber  500  are connected. The location of this gate is determined so as not to interfere with the transfer of the wafer or the movement of the robot arm when the wafer is transferred by the robot arm or wafer transfer device  506  within the transfer chamber  112 . Moreover, when the inner chamber  509  is disposed within the outer chamber  511 , a process gate is located so as to oppose to the gate on the outer chamber or the gate of the transfer chamber  112 , and the wafer is transferred through this process gate.  
         [0069]     Furthermore, a process gate valve  513  for opening and closing the process gate is located in a space interposed between the outer chamber  511  and the inner chamber  509 , the process gate valve  514  capable of being moved both in vertical and horizontal directions via a driving means  521  disposed below the valve  514 . In order to shut the gate, the valve is disposed on the side wall of the inner chamber  509  sealing the gate at the inner side of the side wall, and in order to open the gate, the valve is removed therefrom. The location and shape of the process gate is determined so as not to interfere with the wafer and the robot arm when the wafer is being transferred by the robot arm disposed within the transfer chamber. Further, the shape of the process gate is designed so that when the gate is closed by the process gate valve  513 , the inner walls of inner chambers  509  and  510  do not become uneven.  
         [0070]     According to the present arrangement, all the gate valves are opened when transferring wafers so as not to interfere with the transfer operation. Upon processing the wafer, the process gate valve  513  for closing the gate disposed on the innermost chamber, which according to the present embodiment is the inner chamber  509 , and the atmospheric gate valve  514  disposed on the outer chamber  511  are closed and sealed air tightly, thereby shutting the communication between the inner space of the inner chambers  509  and  510 , the inner space of the outer chambers  511 ,  512 , and the inner space of the transfer chamber  112 .  
         [0071]     When detaching the processing chamber or when opening the vacuum container for maintenance and the like, the process gate valve  513  is opened while the atmospheric gate valve  514  is closed, so that the air of the inside and outside of the inner chamber  509  within the outer chamber  511  are communicated. At this time, a process gas valve  502  is operated to shut off a process gas line  501  so that process gas is not supplied to the processing chamber  500 . As explained, by releasing the process gate valve  513 , the inside and the outside of the inner chamber  509  within the outer chamber  511  are communicated so that their pressure is substantially equalized or controlled appropriately. The load received by the inner chamber  509  or  510  caused by the difference in pressure between the inside and outside of the chamber is minimized, and the required thickness and size of the components can thereby be reduced.  
         [0072]     If the inside of the outer chamber  511  constituting the vacuum container of the processing chamber  500  must be subjected to maintenance, the atmospheric gate valve  514  is closed to seal the outer chamber  511 , and then the process gate valve  513  is opened. When the process gate is released and the air inside and outside the inner chambers  509 ,  510  are in communication, an atmospheric release valve  515  is opened to let the inside air communicate with the outside air of the processing chamber  500 , to thereby raise the pressure within the outside chamber  511  of the processing chamber  500  to substantially reach atmospheric pressure. In other words, the inside of the outside chamber  511  is exposed to the atmosphere. Thereafter, the inside of the processing chamber  500  is opened.  
         [0073]     Next, a lid  503  disposed on the upper portion of the outer chamber  511  of the processing chamber  500  and sealing the chamber is lifted upward and opened. At this time, the lid  503  can be lifted up by a crane or the like, but it is also possible to provide a hinge portion in advance to a portion surrounding the lid  503 , which enables the lid to be rotated via the hinge for 180 degrees or more toward the upper direction. Next, maintenance of the inner chamber  509  is carried out. In order to facilitate maintenance operations such as cleaning, replacing and repairing of parts, the inner chamber  509  can be detached from the outer chamber  511  and taken out from the processing chamber unit  500 .  
         [0074]     According to the present embodiment, the pressure inside and outside the inner chamber  509  can be substantially equalized and thus maintained, so the required thickness of the chamber member can be reduced. Therefore, the weight of the inner chamber  509  can be reduced and maintenance operation such as removal of the inner chamber from the processing chamber is facilitated, so that the work time can be cut down and the operation efficiency of the apparatus improved.  
         [0075]     In the present embodiment, there are two inner chambers, one disposed above the other, the upper chamber  509  disposed above the block of the wafer holder  504  and the lower chamber  510  disposed below the block. The wafer holder  504  block is disposed below the inner chamber  509 . The block of the wafer holder  504  is equipped with a wafer holder body  504  and support beams  520 , the wafer holder being the center axis and support beams disposed axially around the axis. According to the present embodiment, the inner chamber  509 , the outer chamber  511  and the wafer holder  504  have substantially cylindrical shapes, and the gas in the space above the wafer holder  504  within the inner chamber  509  flows downward via the spaces interposed between the support beams in the inner chamber  509 .  
         [0076]     The support beams  520  connect the wafer holder body  504  with a ring-shaped support base member  523  disposed around the body so as to support and fix the wafer holder  504  within the inner chamber  509 . Gas and refrigerant supply pipes and power lines to the wafer holder  504  are disposed to the inside of the support base member  523 , the support beams  520  and hanging beams  505  connected to the support base member  523  and suspending the same in position.  
         [0077]     According to this arrangement, the wafer holder body  504 , the support beams  520  and the support base  523  can be lifted up as one integrated block and taken out of the outer chamber  511 . The maintenance of the wafer holder  504  is not performed as frequently as the maintenance of the inner chamber  509 , so by forming the wafer holder and surrounding components as a single block that can be moved integrally, the efficiency of the maintenance operation of the apparatus is improved.  
         [0078]     A lower inner chamber  510  is disposed below the block of the wafer holder  504 , and an opening is provided to the lower center portion of the inner chamber  510 . This opening is communicated with exhaust means comprising an exhaust valve  507  and an exhaust pump  508  disposed below the wafer holder  504  and at the bottom portion of the inner chamber  510 , through which gas in the inner chamber  509  and flowing around the wafer holder  504  is flown. In other words, the space interposed between supporting beams  520  surrounding the wafer holder  504  and the space within the inner chamber  510  disposed below the wafer holder  504  function as an exhaust path through which the process gas inside the processing chamber  500 , particles of plasma and particles of reaction products are discharged.  
         [0079]     The exhaust valve  507  acting as exhaust means for the processing chamber  500  is a shutter-type exhaust valve comprising plural plate shutters capable of blocking the communication between the space within the inner chamber  510  and the exhaust pump  508  disposed below the valve. Thus, according to the embodiment, the exhaust means is disposed below the wafer holder  504 , preferably directly below the holder. The plasma, the process gas and the reaction products inside the space above the wafer holder  504  in the inner chamber  509  flow through the exhaust path extending via the space around the wafer holder  504  and inside the lower inner chamber  510  toward the exhaust valve  507 .  
         [0080]     The plural support beams  520  are disposed substantially axisymmetric around the center axis of the wafer holder  504 . The support beams are designed so that the lengths of discharge routes extending through the spaces interposed between support beams and reaching the exhaust valve  507  directly below the wafer holder are substantially equal. Thus, the flow of gas, charged particles and reaction products existing in the plasma above the wafer holder becomes uniform with respect to the circumferential direction of the wafer holder and the substantially disc-shaped wafer mounted on the wafer holder, so that the distribution of particles of the substances within the plasma above the wafer becomes very even. As a result, the wafer processing becomes more uniform.  
         [0081]     The exhaust means comprises an exhaust valve  507  with plural shutters and an exhaust pump  508  disposed underneath, wherein the exhaust valve  507  is disposed directly below the wafer holder  504 . The plurality of plate-shaped shutters are disposed substantially horizontally as shown (in the direction of the wafer surface), each shutter capable of being rotated around a mounting axis to thereby adjust the area of the communication passage between the opening of the inner chamber  510  and the exhaust pump  508 . By rotating the shutters via the axes, the plates of the shutters come into contact with each other, sealing the opening. When the plates of the shutters become substantially parallel in the upper direction (in the direction of the wafer holder  504 ), the area of communication becomes greatest. Though not shown, the exhaust valve  507  comprises a drive means such as a motor for controlling the rotation of the shutters, so the exhaust means can control the amount and rate of discharge by adjusting the opening area of these shutters and the operation of the exhaust pump  508 .  
         [0082]      FIG. 7  is used to explain the maintenance operation of the inside of the processing chamber  500 .  FIG. 7  is a vertical cross-sectional view explaining how the components of the processing chamber illustrated in  FIG. 5  are detached.  
         [0083]     After confirming that the pressure inside and outside the inner chamber  509  within the processing chamber  500  are substantially equal, the lid  503  is opened. A crane or the like can be used to lift the lid, or a hinge portion provided to the lid in advance can be used to open the lid via the hinge. From the outer chamber  511  exposed to the atmosphere, the upper inner chamber  509  is lifted up and removed. After either removing the process gate valve  513  from within the outer chamber  511  or by releasing the process gate valve  513  from the inner chamber  509 , the inner chamber  509  is lifted up and taken out of the processing chamber  500 . Thereafter, the process gate valve  513  is detached and taken out of the outer chamber  511 .  
         [0084]     The inner chambers  509  and  510  are disposed so that chamber  509  is located above chamber  510  and having interposed therebetween the support beams  520  and the support base member  523  of the wafer holder  504 . After lifting the integral wafer holder  504  block out of the outer chamber  511 , the lower inner chamber  510  is removed from above, and then maintenance such as cleaning and repairing is carried out to the inner side walls of the outer chamber  511 .  FIG. 8  is referred to in explaining this maintenance operation.  
         [0085]      FIG. 8  is a vertical cross-sectional view explaining how the parts of the processing chamber illustrated in  FIG. 5  is removed.  
         [0086]     As explained, the upper inner chamber  509  is lifted and removed from the processing chamber, and then the wafer holder  504  block is lifted and moved out of the processing chamber  500 .  
         [0087]     This movement can either be realized by rotating the wafer holder block connected through a hanging beam  505  to an outer lid  503  via a hinge provided in advance to the outer lid  503 , or by using a crane and the like to lift the wafer holder block. After taking out the wafer holder  504  block, the lower inner chamber  510  is removed. The upper and lower inner chambers  509  and  510  can be either subjected to maintenance operations such as cleaning and repairing, or replaced with new components. Similarly, the exhaust valve can be subjected to maintenance and replacement when necessary.  
         [0088]     After completing the maintenance operation, the chamber is reassembled in the opposite order as explained above. Then, the lid  503  is attached to the processing chamber  500  before connecting various supply pipes and lines for gas, refrigerant and power.  
         [0089]     As explained, according to the present embodiment, a process gate and a process gate valve for opening and closing the gate is disposed to the position opposing to the gate of the outer chamber within a multiple chamber arrangement. When the atmospheric gate valve disposed to the outer side is closed, the inner area of the processing chamber can be exposed to the atmosphere enabling the processing chamber or parts constituting the same to be removed and attached. Such maintenance (removal, reassembly etc.) of the processing chamber of a processing unit can be carried out while other processing units are carrying out processes.  
         [0090]     According further to the present embodiment, the inside and outside pressures of the inner chamber can be equalized and maintained, enabling the thickness and thus the weight of the inner chamber to be reduced so that mounting and removing operations are facilitated and work efficiency is improved, and as a result, the overall operation efficiency of the apparatus is improved. Further, since the inner chamber is divided into upper and lower parts, the handling of the inner chamber is facilitated, the work time is reduced, and the operation efficiency of the apparatus is further improved. Since the wafer holder and surrounding parts can be handled as a single block of components, the components requiring less frequent maintenance can be removed as one so that the work efficiency is further enhanced.  
         [0091]     Since the exhaust means is disposed below the wafer holder, especially directly under the wafer holder, the route for discharging particles of plasma etc. inside the processing chamber is kept relatively straight. Therefore, the discharge speed is increased, the work time is shortened and the overall operation efficiency of the apparatus is enhanced. Furthermore, by disposing an exhaust valve comprising plural shutters under the wafer holder, the buffer space for the exhaust below the wafer holder is minimized and the exhaust time is shortened. Since the support beams of the wafer holder are disposed substantially axisymmetricly around the wafer holder, the exhaust path extends relatively straightly toward the exhaust means disposed below the wafer holder.  
         [0092]     Moreover, since the plural exhaust paths formed around the wafer holder have substantially equal lengths, the flow of particles of the plasma etc. in the processing chamber becomes uniform and the particle density above the wafer on the wafer holder becomes even, resulting in stable processing of the wafer.