Patent Publication Number: US-2022213594-A1

Title: Process module, substrate processing system, and processing method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2021-000572, filed on Jan. 5, 2021, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a process module, a substrate processing system, and a processing method. 
     BACKGROUND 
     As a process module that performs a process on a substrate (hereinafter, also referred to as a “wafer”) in a substrate processing system, a process module in which four wafers are processed simultaneously in one chamber is known (Patent Document 1). 
     PRIOR ART DOCUMENT 
     Patent Document 
     Patent Document 1: Japanese Laid-Open Patent Publication No. 2019-087576 
     SUMMARY 
     According to one embodiment of the present disclosure, there is provided a process module including four stages arranged in a two-row and two-column layout inside the process module, wherein a row interval and a column interval that constitute the two-row and two-column layout have different dimensions. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure. 
         FIG. 1  is a schematic plan view illustrating an example of a configuration of a substrate processing system in an embodiment of the present disclosure. 
         FIG. 2  is an exploded perspective view illustrating an example of a configuration of a substrate processing apparatus in an embodiment. 
         FIG. 3  is a view illustrating an example of a positional relationship between a processing space and a rotation arm at a standby position. 
         FIG. 4  is a view illustrating an example of a positional relationship between the processing space and the rotation arm at a wafer holding position. 
         FIG. 5  is a view illustrating an example of a movement path of wafers in the substrate processing apparatus in the embodiment. 
         FIG. 6  is a view illustrating an example of an exhaust path of the substrate processing apparatus in the embodiment. 
         FIG. 7  is a schematic cross-sectional view illustrating an example of a configuration of the substrate processing apparatus in the embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of a process module, a substrate processing system, and a processing method disclosed herein will be described in detail with reference to the drawings. The technology disclosed herein is not limited by the following embodiments. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments. 
     A process module in which four wafers are processed simultaneously in one chamber includes four stages on which the four wafers are placed, respectively. This results in an increase in footprint. However, in a factory in which a substrate processing system is installed, it is required to reduce the footprint in order to improve space efficiency. In addition, there may be a case in which a process module in which two wafers are processed simultaneously in one chamber is connected to a vacuum transfer chamber through which the wafer is loaded into or unloaded from the process module. That is, process modules of different sizes may be connected to the vacuum transfer chamber. In such a case, a wafer transfer mechanism corresponding to each of the process modules of different sizes is provided in the vacuum transfer chamber. Therefore, it is required to reduce the footprint of the process module and to share the wafer transfer mechanism. 
     Embodiment 
     [Configuration of Substrate Processing System] 
       FIG. 1  is a schematic plan view illustrating an example of a configuration of a substrate processing system in an embodiment of the present disclosure. A substrate processing system  1  illustrated in  FIG. 1  includes loading/unloading ports  11 , a loading/unloading module  12 , vacuum transfer modules  13   a  and  13   b , and substrate processing apparatuses  2 ,  2   a , and  2   b . In  FIG. 1 , the X direction will be referred to as a left-right direction, the Y direction will be referred to as a front-rear direction, the Z direction will be referred to as an up-down direction (height direction), and the side having the loading/unloading ports  11  will be referred to as a front side in the front-rear direction. The loading/unloading ports  11  are connected to the front side of the loading/unloading module  12 , and the vacuum transfer module  13   a  is connected to the rear side of the loading/unloading module  12  in the front-rear direction. 
     Carriers, which are transfer containers accommodating substrates to be processed, are placed on the loading/unloading ports  11 , respectively. The substrate is a wafer W, which is a circular substrate having a diameter of, for example, 300 mm. The loading/unloading module  12  is a module configured to perform loading/unloading of the wafers W between the carriers and the vacuum transfer module  13   a . The loading/unloading module  12  includes a normal-pressure transfer chamber  121  in which the wafers W are delivered to and from the carriers in a normal-pressure atmosphere by a transfer mechanism  120 , and a load-lock chamber  122  in which the atmosphere in which the wafers W are placed is switched between the normal-pressure atmosphere and a vacuum atmosphere. 
     The vacuum transfer modules  13   a  and  13   b  have vacuum transfer chambers  14   a  and  14   b , respectively, in which a vacuum atmosphere is formed. Substrate transfer mechanisms  15   a  and  15   b  are disposed inside the vacuum transfer chambers  14   a  and  14   b , respectively. Between the vacuum transfer module  13   a  and the vacuum transfer module  13   b , a path  16  in which the delivery of the wafer W is performed between the vacuum transfer modules  13   a  and  13   b  is disposed. Each of the vacuum transfer chambers  14   a  and  14   b  is formed in, for example, a rectangular shape in a plan view. The substrate processing apparatuses  2  and  2   b  are respectively connected to sides facing each other in the left-right direction among the four sidewalls of the vacuum transfer chamber  14   a . The substrate processing apparatuses  2   a  and  2   b  are respectively connected to sides facing each other in the left-right direction among four sidewalls of the vacuum transfer chamber  14   b.    
     The load-lock chamber  122  installed in the loading/unloading module  12  is connected to the front side among the four sidewalls of the vacuum transfer chamber  14   a . Gate valves G are arranged between the normal-pressure transfer chamber  121  and the load-lock chamber  122 , between the load-lock chamber  122  and the vacuum transfer module  13   a , and between the vacuum transfer modules  13   a  and  13   b  and the substrate processing apparatuses  2 ,  2   a , and  2   b , respectively. Each gate valve G opens and closes the loading/unloading port for the wafer W, which is provided between the modules connected to each other. 
     The substrate transfer mechanism  15   a  transfers the wafers W among the loading/unloading module  12 , the substrate processing apparatuses  2  and  2   b , and the path  16  in a vacuum atmosphere. In addition, the substrate transfer mechanism  15   b  transfers the wafers W between the path  16  and the substrate processing apparatuses  2   a  and  2   b  in a vacuum atmosphere. Each of the substrate transfer mechanisms  15   a  and  15   b  is configured with an articulated arm, and includes a substrate holder configured to hold the wafer W. Each of the substrate processing apparatuses  2 ,  2   a , and  2   b  collectively processes a plurality of (e.g., two or four) wafers W using a process gas in a vacuum atmosphere. To do this, the substrate holder of each of the substrate transfer mechanisms  15   a  and  15   b  is configured to be capable of simultaneously holding, for example, two wafers W to collectively deliver the two wafers W to the substrate processing apparatus  2 ,  2   a , or  2   b . The substrate processing apparatuses  2  (or  2   a ) may be configured to use a rotation arm provided therein, and transfer the wafer W received by an outer stage located close to the vacuum transfer module  13   a  (or  13   b ) to an inner stage. Each of the substrate transfer mechanisms  15   a  and  15   b  is an example of a wafer transfer mechanism. 
     In the substrate processing apparatuses  2 ,  2   a , and  2   b , a pitch Py between the stages in the Y direction (row interval) is the same. Thus, the substrate processing apparatuses  2 ,  2   a , and  2   b  can be connected to any locations of the sides of the vacuum transfer modules  13   a  and  13   b , which are opposite to each other in the left-right direction. In the example of  FIG. 1 , the substrate processing apparatus  2  and the substrate processing apparatus  2   b  are connected to the vacuum transfer module  13   a , and the substrate processing apparatus  2   a  and the substrate processing apparatus  2   b  are connected to the vacuum transfer module  13   b . The substrate processing apparatus  2  and the substrate processing apparatus  2   a  differ from each other in the diameter of a reactor including a processing space corresponding to one stage according to a process application, and thus have different pitches Px 1  and Px 2 , which are pitches between the stages in the X direction (column interval), respectively. In the substrate processing apparatus  2   a , the pitch Px 2  has the same value as the pitch Py. That is, the pitch Py corresponds to the size of the largest reactor. That is, since the size of the reactor of the substrate processing apparatus  2  is smaller than that of the substrate processing apparatus  2   a , the pitch Px 1  may be set to be smaller than the pitch Px 2 . 
     An internal configuration of the substrate processing apparatus  2   a  is essentially identical to that of the substrate processing apparatus  2 , except that the pitch Px 2  is different from the pitch Px 1 , and a description thereof will be omitted. The substrate processing apparatus  2   b  has two stages and is configured to simultaneously load two wafers thereinto to perform processing on the two wafers, and simultaneously unload the processed two wafers therefrom, rather than performing the transfer of the wafers W therein. For the sake of convenience in the description, in the XYZ coordinate system illustrated in  FIG. 1 , the pitch in the X direction is defined as the column interval, and the pitch in the Y direction is defined as the row interval. However, for example, the substrate processing apparatuses  2  (or  2   a ) may be disposed at the inner side of the vacuum transfer module  13   b . In this case, it is necessary to consider changing the column interval and the row interval. That is, it is necessary to consider which is the row and which is the column based on the surfaces of the substrate processing apparatuses  2  and  2   a  that are in contact with the vacuum transfer modules  13   a  and  13   b , respectively. 
     The substrate processing system  1  includes a controller  8 . The controller  8  is, for example, a computer including a processor, a storage part, an input device, a display device, and the like. The controller  8  controls each part of the substrate processing system  1 . With the controller  8 , an operator may perform a command input operation or the like using the input device in order to manage the substrate processing system  1 . In addition, under the control of the controller  8 , the operation state of the substrate processing system  1  may be visually displayed on the display device. In addition, the storage part of the controller  8  stores a control program, recipe data, and the like used by the processor to control various processes to be executed by the substrate processing system  1 . The processor of the controller  8  executes the control program to control each part of the substrate processing system  1  according to the recipe data, whereby desired substrate processing is executed in the substrate processing system  1 . 
     [Configuration of Substrate Processing Apparatus] 
     Next, an example in which the substrate processing apparatus  2  is applied to, for example, a film forming apparatus that performs a plasma chemical vapor deposition (CVD) process on wafers W will be described with reference to  FIGS. 2 to 7 . A substrate processing apparatus  2  is an example of a process module.  FIG. 2  is an exploded perspective view illustrating an example of a configuration of a substrate processing apparatus in the present embodiment. As illustrated in  FIG. 2 , the substrate processing apparatus  2  includes a processing container (vacuum container)  20  having a rectangular shape in a plan view. The processing container  20  is configured to keep the interior thereof in a vacuum atmosphere. The processing container  20  is defined by closing an upper opening portion with a gas supplier  4  and a manifold  36  to be described later. In  FIG. 2 , internal partition walls and the like are omitted such that a relationship between a plurality of processing spaces S 1  to S 4  and a rotation arm  3  can be easily understood. The processing container  20  includes two loading/unloading ports  21  formed in the side surface thereof connected to the vacuum transfer chamber  14   a  (or  14   b ) and arranged in the Y direction. The loading/unloading ports  21  are opened and closed by the gate valves G, respectively. 
     The plurality of processing spaces S 1  to S 4  are provided inside the processing container  20 . A stage  22  is arranged in each of the processing spaces S 1  to S 4 . The stage  22  is movable vertically. Specifically, the stage  22  moves upward when the wafer W is processed, and moves downward when the wafer W is transferred. Under the processing spaces S 1  to S 4 , a transfer space T in which the wafers W are transferred by the rotation arm  3  is provided to be connected to the processing spaces S 1  to S 4 . In addition, the transfer space under the processing spaces S 1  and S 2  in the transfer space T is connected to each loading/unloading port  21  so that loading/unloading of the wafers W is performed between the vacuum transfer chambers  14   a  and  14   b  by the substrate transfer mechanisms  15   a  and  15   b.    
     The respective stages  22  of the processing spaces S 1  to S 4  are arranged in a two-row and two-column layout when viewed from the above. This layout has different dimensions in row and column intervals. That is, the pitch Py, which is a pitch in the Y-direction between the stages  22  (row interval), and the pitch Px 1 , which a pitch in the X-direction between the stages  22  (column interval), have a relationship of Py&gt;Px 1 . 
       FIG. 3  is a view illustrating an example of a positional relationship between the processing spaces and the rotation arm at a standby position.  FIG. 4  is a view illustrating an example of a positional relationship between the processing spaces and the rotation arm at a wafer holding position. As illustrated in  FIGS. 3 and 4 , the rotation arm  3  has four end effectors  32  capable of holding the wafers W to be placed on the stages  22 , respectively, and a base member  33  having a rotation axis at the center position of the two-row and two-column layout. The four end effectors  32  are connected to the base member  33  to form an X shape. The X shape of the rotation arm  3  has a configuration in which a dimension in the Y direction, which corresponds to the row interval of the X shape, and a dimension in the X direction, which corresponds to the column interval of the X shape, are different from each other at the wafer holding position illustrated in  FIG. 4 . 
     At the standby position illustrated in  FIG. 3 , the rotation arm  3  is disposed between two adjacent processing spaces of the processing spaces S 1  to S 4 , so that the rotation arm  3  do not interfere with the vertical movement of each stage  22 .  FIG. 3  illustrates the state in which the wafer W is placed on each stage  22 . A description will be made as to the movement of the rotation arm  3  when the wafers W are transferred such that the wafers W in the first column and the wafers W in the second column are interchanged from this state, that is, when the wafers W in the processing spaces S 1  and S 2  are transferred to the processing spaces S 3  and S 4 , and the wafers W in the processing spaces S 3  and S 4  are transferred to the processing spaces S 1  and S 2 . 
     First, respective stages  22  are moved to delivery positions in the transfer space T at the lower side, and lift pins  26  (to be described later) provided on the respective stages  22  are raised to lift the wafers W. Subsequently, the rotation arm  3  is rotated clockwise by about 30 degrees to insert respective end effectors  32  between the stages  22  and the wafers W as illustrated in  FIG. 4 . Subsequently, the lift pins  26  are lowered to place the wafers W on respective end effectors  32 . Subsequently, the rotation arm  3  is rotated clockwise by 180 degrees to transfer the wafers W to holding positions on respective stages  22 . When the respective stages  22  raise the lift pins  26  to receive the wafers W, the rotation arm  3  is rotated counterclockwise by about 30 degrees to move to the standby position. In this way, the wafers W can be transferred by the rotation arm  3  such that the wafers W in the first column and the wafers W in the second column are interchanged with each other. Therefore, for example, when different processes are repeated in the processing spaces S 1  and S 2  and the processing spaces S 3  and S 4  (e.g., when a film forming process and an annealing process are repeated), the time required to transfer the wafers W can be reduced. 
       FIG. 5  is a view illustrating an example of wafer movement paths in the substrate processing apparatus in the present embodiment. In  FIG. 5 , the movement paths when the wafers W are transferred from the vacuum transfer chamber  14   a  to the interior of the substrate processing apparatus  2  will be described. First, by the substrate transfer mechanism  15   a  of the vacuum transfer chamber  14   a , as illustrated by a path F 1 , at the delivery positions of the transfer space T under the processing spaces S 1  and S 2  corresponding to the stages  22  in the same column, two wafers W are simultaneously loaded into respective stages  22 . The respective stages  22  of the processing spaces S 1  and S 2  raise the lift pins  26  to receive the wafers W. 
     Subsequently, the rotation arm  3  is rotated clockwise from the standby position by about 30 degrees, the end effectors  32  are inserted between the stages  22  located at the delivery positions under the processing spaces S 1  and S 2  and the wafers W, respectively, and the lift pins  26  are lowered to place the wafers W on the respective end effectors  32 . When the wafers W are placed, the rotation arm  3  is rotated clockwise by  180  degrees as illustrated by a path F 2  to transfer the wafers W onto the stages  22  located at the delivery positions (the holing positions of the rotation arm  3 ) of the transfer space T under the processing spaces S 3  and S 4 . When the stages  22  located at the delivery positions under the processing spaces S 3  and S 4  raise the lift pins  26  to receive the wafers W, respectively, the rotation arm  3  is rotated counterclockwise by about 30 degrees to move to the standby position. In this state, no wafers W are placed on the stages  22  of the processing spaces S 1  and S 2 , but the wafers W are placed on the stages  22  of the processing spaces S 3  and S 4 . Subsequently, as illustrated by the path F 1 , two wafers W are simultaneously loaded into respective stages  22  at the delivery positions located under the processing spaces S 1  and S 2  by the substrate transfer mechanism  15   a  of the vacuum transfer chamber  14 a, and the wafers W are placed on the stages  22  of the processing spaces S 1  and S 2 , whereby the wafers W are placed on all of the stages  22  of the processing spaces S 1  to S 4 , respectively. 
     Similarly, during unloading, the wafers W placed on the stages  22  located at the delivery positions under the processing spaces S 1  and S 2  are first transferred to the vacuum transfer chamber  14   a  by the substrate transfer mechanism  15   a . Subsequently, the wafers W placed on the stages  22  located at the delivery positions under the processing spaces S 3  and S 4  are transferred by the rotation arm  3  to the stages  22  located at the delivery positions under the processing spaces S 1  and S 2 . Subsequently, the wafers W placed on the stages  22  located at the delivery positions under the processing spaces S 1  and S 2  are transferred to the vacuum transfer chamber  14   a  by the substrate transfer mechanism  15   a . In this way, by using the substrate transfer mechanism  15   a  capable of simultaneously transferring two wafers W and the rotation arm  3 , the wafers W can be loaded into and unloaded from the processing spaces S 1  to S 4 . 
     When the rotation arm  3  transfers the wafers W, the deviations of the wafers W from the stages  22  of a transfer destination may be detected, and the stages  22  may be finely moved in the XY plane to correct the deviation of the wafers W. In this case, the substrate processing apparatus  2  includes a deviation detection sensor configured to detect the deviation of each wafer W at each of rotationally symmetric positions within the row interval or the column interval, on the rotation trajectory of the wafers W held by the rotation arm  3 . In the example of  FIG. 5 , sensors  31   a  and  31   b  are provided between the processing spaces S 1  and S 2  and between the processing spaces S 3  and S 4 , respectively, within the row interval. 
     Each of the sensors  31   a  and  31   b  is, for example, a set of two optical sensors, which are arranged on a straight line in the X direction that passes through the center of the substrate processing apparatus  2 , that is, the center position of the two-row and two-column layout. This is to make the direction of expansion of the processing container  20  caused by a thermal expansion the same in the two sensors, thereby reducing an error. The arrangement positions of the sensors  31   a  and  31   b  are not limited to the X direction as long as the positions are on the straight line passing through the center of the substrate processing apparatus  2 . The substrate processing apparatus  2  detects deviation amounts of the wafers W by comparing front and rear edges of the wafers W detected by the sensors  31   a  and  31   b  with output results of an encoder (not illustrated) provided in the rotation arm  3 . 
     In the example of  FIG. 5 , a position P 24  represents a state in which the rear edge of the wafer W passes through the sensor  31   b  when the wafer W is transferred from the processing space S 2  to the processing space S 4 , and a position P 42  represents a state in which the rear edge of the wafer W passes through the sensor  31   a  when the wafer W is transferred from the processing space S 4  to the processing space S 2 . The substrate processing apparatus  2  may finely move the stages  22  within the XY plane according to a detected deviation amount to correct the deviations of the wafers W. That is, the substrate processing apparatus  2  adjusts the deviations such that the wafers W are located at the centers of the processing spaces S 1  to S 4 , respectively, when the stages  22  are raised. The term “finely” used herein refers to about 5 mm or less. 
       FIG. 6  is a view illustrating an example of exhaust paths of the substrate processing apparatus in the present embodiment.  FIG. 6  illustrates a case in which the processing container  20  is viewed from above in the state in which the gas supplier  4  (to be described later) is removed. As illustrated in  FIG. 6 , a manifold  36  is arranged in the center of the substrate processing apparatus  2 . The manifold  36  includes a plurality of exhaust paths  361 , which are connected to the processing spaces S 1  to S 4 , respectively. Each exhaust path  361  is connected to a hole  351  in a thrust nut  35  (to be described later) below the center of the manifold  36 . Each exhaust path  361  is connected to an annular flow path  363  in each of the guide members  362  provided above the processing spaces S 1  to S 4 . That is, the gas in the processing spaces S 1  to S 4  is exhausted to a joined exhaust port  205  (to be described later) via the flow path  363 , the exhaust paths  361 , and the hole  351 . 
       FIG. 7  is a schematic cross-sectional view illustrating an example of a configuration of the substrate processing apparatus in the present embodiment. The cross section of  FIG. 7  corresponds to the cross section of the substrate processing apparatus  2  taken along line A-A in  FIG. 6 . The four processing spaces S 1  to S 4  are configured in the same manner as each other, and are formed between the stages  22 , on each of which the wafer W is placed, and the gas suppliers  4  disposed to face the stages  22 , respectively. In other words, in the processing container  20 , the stage  22  and the gas supplier  4  are provided for each of the four processing spaces S 1  to S 4 .  FIG. 7  illustrates the processing spaces S 1  and S 3 . Hereinafter, the processing space S 1  will be described as an example. 
     The stage  22  also serves as a lower electrode, is made of, for example, a metal or aluminum nitride (AlN) in which a metal mesh electrode is embedded, and is formed in a flat column shape. The stage  22  is supported by a support member  23  from the bottom side. The support member  23  is formed in a cylindrical shape, extends vertically downward, and penetrates a bottom  27  of the processing container  20 . A lower end portion of the support member  23  is located outside the processing container  20  and connected to a rotational driving mechanism  600 . The support member  23  is rotated by the rotational driving mechanism  600 . The stage  22  is configured to be rotatable with the rotation of the support member  23 . An adjustment mechanism  700  is provided at the lower end portion of the support member  23  to adjust the position and inclination of the stage  22 . The stage  22  is configured to be capable of being raised and lowered between a processing position and a delivery position using the support member  23  by the adjustment mechanism  700 . In  FIG. 7 , the stage  22  located at the delivery position is indicated by the solid line, and the stage  22  located at the processing position is indicated by the broken line. In addition, at the delivery position, the end effector  32  is inserted between the stage  22  and the wafer W to receive the wafer W from the lift pins  26 . The processing position is a position when substrate processing (e.g., a film forming process) is executed, and the delivery position is a position at which the wafer W is delivered to and from the substrate transfer mechanism  15   a  or the end effector  32 . 
     A heater  24  is embedded in each stage  22 . The heater  24  heats each wafer W placed on the stage  22  to, for example, about 60 degrees C. to 600 degrees C. In addition, the stage  22  is connected to a ground potential. 
     In addition, the stage  22  is provided with a plurality of (e.g., three) pin through-holes  26   a , and the lift pins  26  are arranged inside these pin through-holes  26   a , respectively. The pin through-holes  26   a  are provided to penetrate the stage  22  from a placement surface (top surface) of the stage  22  to a rear surface (bottom surface) opposite to the placement surface. The lift pins  26  are slidably inserted into the respective pin through-holes  26   a . Upper ends of the lift pins  26  are suspended at placement-surface sides of the pin through-holes  26   a . That is, the upper ends of the lift pins  26  have a diameter larger than those of the pin through-holes  26   a , and recesses having a diameter and a thickness larger than those of the upper ends of the lift pins  26  are formed at the upper ends of the pin through-holes  26   a  to be capable of accommodating the upper ends of the lift pins  26 , respectively. As a result, the upper ends of the lift pins  26  are engaged with the stage  22  and suspended at the placement-surface sides of the pin through-holes  26   a , respectively. In addition, the lower ends of the lift pins  26  protrude from the rear surface of the stage  22  toward the bottom  27  of the processing container  20 . 
     In the state in which the stage  22  is raised to the processing position, the upper ends of the lift pins  26  are received in the recesses at the placement-surface sides of the pin through-holes  26   a , respectively. When the stage  22  is lowered to the delivery position from this state, the lower ends of the lift pins  26  come into contact with the bottom  27  of the processing container  20  and the lift pins  26  move in the pin through-holes  26   a  such that the upper ends of the lift pins  26  protrude from the placement surface of the stage  22 , as illustrated in  FIG. 7 . In this case, the lower ends of the lift pins  26  may be configured to come into contact with, for example, a lift-pin contact member located at the bottom side, instead of the bottom  27  of the processing container  20 . 
     The gas supplier  4  is provided in a ceiling portion of the processing container  20  and above the stage  22  via a guide member  362  made of an insulating member. The gas supplier  4  has a function as an upper electrode. The gas supplier  4  includes a lid  42 , a shower plate  43  forming a facing surface provided to face the placement surface of the stage  22 , and a gas flow chamber  44  formed between the lid  42  and the shower plate  43 . A gas supply pipe  51  is connected to the lid  42 , and gas ejection holes  45  penetrating the shower plate  43  in the thickness direction are arranged vertically and horizontally in the shower plate  43  such that the gas is ejected toward the stage  22  in the form of a shower. 
     Each gas supplier  4  is connected to a gas supply system  50  via a gas supply pipe  51 . The gas supply system  50  includes, for example, sources of a reaction gas (a film forming gas), a purge gas, and a cleaning gas, which are processing gases, a pipe, a valve V, a flow rate adjuster M, and the like. The gas supply system  50  includes, for example, a cleaning gas source  53 , a reaction gas source  54 , a purge gas source  55 , valves V 1  to V 3  provided in the pipes of respective gas sources, and flow rate adjusters M 1  to M 3 . 
     The cleaning gas source  53  is connected to a cleaning gas supply path  532  via the flow rate adjuster M 1 , the valve V 1 , and a remote plasma unit (RPU)  531 . The cleaning gas supply path  532  branches into four systems at the downstream side of the RPU  531  to be connected to each gas supply pipe  51 . Valves V 11  to V 14  are provided for respective branched pipes at the downstream side of the RPU  531 . The respective valves V 11  to V 14  are opened during cleaning. For the sake of convenience in illustration, only the valves V 11  and V 14  are illustrated in  FIG. 7 . 
     The reaction gas source  54  and the purge gas source  55  are connected to a gas supply path  52  via the flow rate adjusters M 2  and M 3  and the valves V 2  and V 3 , respectively. The gas supply path  52  is connected to the gas supply pipe  51  via the gas supply pipe  510 . In  FIG. 7 , the gas supply path  52  and the gas supply pipe  510  collectively illustrate respective supply paths and respective supply pipes corresponding to respective gas suppliers  4 . 
     A radio-frequency power supply  41  is connected to the shower plate  43  via a matcher  40 . The shower plate  43  has a function as an upper electrode facing the stage  22 . When radio-frequency power is applied between the shower plate  43 , which is the upper electrode, and the stage  22 , which is the lower electrode, it is possible to plasmarize a gas supplied from the shower plate  43  to the processing space S 1  (a reaction gas in this example) by capacitive coupling. 
     Next, the exhaust paths from the processing spaces S 1  to S 4  to the joined exhaust port  205  will be described. As illustrated in  FIGS. 6 and 7 , the exhaust paths pass through respective exhaust paths  361  from the annular flow paths  363  in respective guide members  362  provided above the processing spaces S 1  to S 4 , and are directed to a joined exhaust port  205  via a junction portion and the hole  351  below the center of the manifold  36 . The exhaust paths  361  have, for example, a circular cross section. 
     Around each of the processing spaces S 1  to S 4 , a guide member  362  used for exhaust is provided to surround each of the processing spaces S 1  to S 4 . The guide member  362  is, for example, an annular body, which is provided to surround a region around the stage  22  located at the processing position with an interval from the stage  22 . The guide member  362  is configured to form therein a flow path  363  having, for example, a rectangular vertical cross section and an annular shape in a plan view. In  FIG. 6 , the processing spaces S 1  to S 4 , the guide members  362 , the exhaust paths  361 , and the manifold  36  are schematically illustrated. 
     The guide members  362  form slit-shaped slit exhaust ports  364 , which are open toward respective processing spaces S 1  to S 4 . In this way, the slit exhaust ports  364  are formed in the side peripheral portions of respective processing spaces S 1  to S 4  in the circumferential direction. The exhaust paths  361  are connected to the flow paths  363 , and the processing gas exhausted from the slit exhaust ports  364  is allowed to flow toward the junction portion and the hole  351  below the center of the manifold  36 . 
     As illustrated in  FIG. 6 , the set of processing spaces S 1  and S 2  and the set of processing spaces S 3  and S 4  are arranged rotationally symmetrically by 180 degrees around the manifold  36  when viewed from the above. As a result, processing-gas flow paths extending from respective processing spaces S 1  to S 4  to the hole  351  via the slit exhaust ports  364 , the flow paths  363  in the guide members  362 , and the exhaust paths  361  are formed rotationally symmetrically by 180 degrees to surround the hole  351 . 
     The hole  351  is connected to the exhaust pipe  61  via the joined exhaust port  205  inside a thrust pipe  341  of a biaxial vacuum seal  34  arranged in the central portion of the processing container  20 . The exhaust pipe  61  is connected to a vacuum pump  62  constituting a vacuum exhaust mechanism via a valve mechanism  7 . One vacuum pump  62  is provided in, for example, one processing container  20 , and the exhaust pipes at the downstream sides of respective vacuum pumps  62  are joined and are connected to, for example, a factory exhaust system. 
     The valve mechanism  7  opens and closes the processing-gas flow path formed in each exhaust pipe  61 , and includes, for example, a casing  71  and an opening/closing part  72 . A first opening  73  connected to the exhaust pipe  61  located at the upstream side is formed in the top surface of the casing  71 , and a second opening  74  connected to the exhaust pipe  61  located at the downstream side is formed in the side surface of the casing  71 . 
     The opening/closing part  72  includes, for example, an opening/closing valve  721  formed to have such a size as to close the first opening  73 , and a lifting mechanism  722  provided outside the casing  71  so as to raise and lower the opening/closing valve  721  inside the casing  71 . The opening/closing valve  721  is configured to be capable of being raised and lowered between a closing position (indicated by the alternated long and short dash line in  FIG. 7 ) at which the first opening  73  is closed and an opening position (indicated by the solid line in  FIG. 7 ) displaced below the first and second openings  73 . When the opening/closing valve  721  is located at the closing position, the downstream end of the joined exhaust port  205  is closed, and the exhaust of the interior of the processing container  20  is stopped. In addition, when the opening/closing valve  721  is located at the opening position, the downstream end of the joined exhaust port  205  is opened and the interior of the processing container  20  is exhausted. 
     Next, the bi-axial vacuum seal  34  and the thrust nut  35  will be described. The biaxial vacuum seal  34  includes a thrust pipe  341 , bearings  342  and  344 , a rotor  343 , a main body  345 , magnetic fluid seals  346  and  347 , and a direct drive motor  348 . 
     The thrust pipe  341  is a non-rotating central shaft and receives a thrust load applied to the upper center of the substrate processing apparatus  2  via the thrust nut  35 . That is, the thrust pipe  341  receives a vacuum load applied to the central portion of the substrate processing apparatus  2  when the interiors of the processing spaces S 1  to S 4  become a vacuum atmosphere, thereby suppressing the deformation of the upper portion of the substrate processing apparatus  2 . The thrust pipe  341  has a hollow structure, and the interior of the thrust pipe  341  forms the joined exhaust port  205 . The top surface of the thrust pipe  341  is in contact with the bottom surface of the thrust nut  35 . In addition, the inner surface of the upper portion of the thrust pipe  341  and the outer surface of a convex portion at the inner peripheral side of the thrust nut  35  are sealed by an O-ring (not illustrated). 
     The outer peripheral side surface of the thrust nut  35  has a screw structure, and the thrust nut  35  is screwed to a partition wall of the central portion of the processing container  20 . The manifold  36  is provided above the central portion of the processing container  20 . The thrust load is received by the manifold  36 , the partition wall in the central portion of the processing container  20 , the thrust nut  35 , and the thrust pipe  341 . 
     The bearing  342  is a radial bearing that holds the rotor  343  at the side of the thrust pipe  341 . The bearing  344  is a radial bearing that holds the rotor  343  at the side of the main body  345 . The rotor  343  is arranged concentrically with the thrust pipe  341  and is a rotation shaft in the center of the rotation arm  3 . In addition, the base member  33  is connected to the rotor  343 . When the rotor  343  rotates, the rotation arm  3 , that is, the end effectors  32  and the base member  33  rotate. 
     The main body  345  accommodates therein the bearings  342  and  344 , the rotor  343 , the magnetic fluid seals  346  and  347 , and the direct drive motor  348 . The magnetic fluid seals  346  and  347  are arranged at the inner peripheral side and the outer peripheral side of the rotor  343 , and seal the processing spaces S 1  to S 4  from the outside. The direct drive motor  348  is connected to the rotor  343 , and drives the rotor  343  to rotate the rotation arm  3 . 
     In this way, in the bi-axial vacuum seal  34 , the thrust pipe  341 , which is the central axis as a first axis that does not rotate, plays the role of a gas exhaust pipe while supporting the load of the upper portion of the processing container  20 , and the rotor  343  as a second axis plays the role of rotating the rotation arm  3 . 
     As described above, according to the embodiment, the process module (the substrate processing apparatus  2 ) includes the four stages  22  arranged in a two-row and two-column layout inside the process module, wherein the row interval and column interval constituting the layout have different dimensions. As a result, it is possible to reduce the footprint of the process module and share the wafer transfer mechanism. 
     According to the embodiment, the process module further includes the rotation arm  3  provided with the four end effectors  32 , each of which is capable of holding the wafer W to be placed on each of the four stages  22 , and the base member  33  having a rotation shaft located at the center position of the layout. The four end effectors  32  are connected to the base member  33  to form an X shape. In the X shape, the dimension in the Y direction, which corresponds to the row interval, and the dimension in the X direction, which corresponds to the column interval, are different from each other. As a result, it is possible to reduce the footprint of the process module and share the wafer transfer mechanism. 
     According to the embodiment, the process module further includes the deviation detection sensor  31   a  or  31   b  configured to detect the deviation of the wafer W at each of rotationally symmetric positions within the row interval or the column interval on a rotation trajectory of the wafer W held by the rotation arm  3 . As a result, it is possible to correct the deviations of the wafers W at the time of transferring the wafers by the rotation arm  3 . 
     According to the embodiment, each of the four stages  22  is finely movable in at least an XY plane according to the position of the wafer W detected by the deviation detection sensor. As a result, it is possible to correct the deviation of the wafer W, which is caused during the transfer or the like performed by the rotation arm  3 . 
     According to the embodiment, two wafers W placed on the stages  22  in the same column can be transferred simultaneously. As a result, a two-wafer-type substrate processing apparatus and the wafer transfer mechanism can be communalized. 
     According to the embodiment, the substrate processing system  1  includes the plurality of process modules (the substrate processing apparatuses  2  and  2   a ) connected to the vacuum transfer chamber  14   a  or  14   b  equipped with the wafer transfer mechanism (the substrate transfer mechanism  15   a  or  15   b ). Each of the plurality of process modules includes four stages arranged in a two-row and two-column layout therein. In each of the plurality of process modules, a pitch in the Y direction between the stages of the layout, which is a direction along a surface facing the vacuum transfer chamber  14   a  or  14   b , is the same between one process module and another process module among the plurality of process modules. A pitch in the X direction between the stages of the layout, which is a direction perpendicular to the surface facing the vacuum transfer chamber  14   a  or  14   b , differs between one process module and the another process module. As a result, it is possible to make process modules having different footprints coexist, and share the wafer transfer mechanism. 
     According to the embodiment, in the processing method used in the process module (the substrate processing apparatus  2 ), the process module includes: the four stages  22  arranged therein in a two-row and two-column layout, wherein the row interval and the column interval constituting the layout have different dimensions; and the rotation arm  3  including four end effectors  32 , each of which is capable of holding the wafer W to be placed on each of the four stages  22 , and the base member  33  having the rotation shaft located at the center position of the layout, wherein the four end effectors  32  are connected to the base member  33  to form an X shape. In the X shape, the dimension in the Y direction, which corresponds to the row interval, and the dimension in the X direction, which corresponds to the column interval, are different from each other. In the processing method, by transferring the wafers W in a first column and a second column to be exchanged with each other by the rotation arm  3 , different processes are repeated in the first column and the second column. As a result, it is possible to reduce the time required to transfer the wafers W between respective processes. 
     It shall be understood that the embodiments disclosed herein are illustrative and are not limiting in all aspects. The above-described embodiments may be omitted, replaced, or modified in various forms without departing from the scope and spirit of the appended claims. 
     For example, in the embodiments described above, an example in which the substrate processing apparatus  2  is an apparatus that performs a plasma CVD process as substrate processing has been described, but the technique disclosed herein may be applied to any apparatus that performs other substrate processing such as plasma etching. 
     In addition, in the above-described embodiments, the direct drive motor  348  is used as a constituent element that drives the rotor  343  in the biaxial vacuum seal  34 , but the present disclosure is not limited thereto. For example, the rotor  343  may be provided with a pulley and may be driven using a timing bell from a motor provided outside the biaxial vacuum seal  34 . 
     According to the present disclosure, it is possible to reduce an increase in footprint of a process module and a substrate processing system. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosures. Indeed, the embodiments described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosures. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosures.