Patent Publication Number: US-2022230904-A1

Title: Substrate processing system and method for controlling substrate processing system

Description:
TECHNICAL FIELD 
     The present disclosure relates to a substrate processing system and a method of controlling the substrate processing system. 
     BACKGROUND 
     Patent Document 1 discloses a correction method of correcting a transfer position to which an object is transferred, in a transfer device having a holding part for holding the object, a linear second arm having an end portion connected to the holding part, and a linear first arm connected to the other end portion of the second arm via a joint portion. The correction method includes a step of calculating a position of the holding part from rotation angles of the first arm and the second arm, a step of detecting position information of the second arm by a position detection sensor that detects a position of the second arm, and a step of comparing the position information of the second arm detected by the position detection sensor with position information of the holding part calculated from the rotation angles of the first arm and the second arm and correcting the transfer position to which the object is transferred, based on a difference between the position information of the second arm and the position information of the holding part. 
     PRIOR ART DOCUMENTS 
     Patent Document 
     
         
         Japanese laid-open publication No. 2017-100261 
       
    
     However, the correction method of the transfer device disclosed in Patent Document 1 is for a transfer device that transfers one substrate, and Patent Document 1 does not disclose a transfer device that transfers a plurality of substrates. 
     An aspect of the present disclosure provides a substrate processing system, which includes a transfer device that simultaneously transfers a plurality of substrates and which is capable of suitably correcting positions of the substrate, and a method of controlling the substrate processing system. 
     SUMMARY 
     According to an aspect of the present disclosure, there is provided a substrate processing system including: a process chamber in which a plurality of substrates is processed; a vacuum transfer chamber connected to the process chamber; a transfer device provided in the vacuum transfer chamber and configured to simultaneously transfer a plurality of substrates; a module connected to the vacuum transfer chamber and having a plurality of stages on which substrates are placed; and a controller. The controller is configured to measure an amount of change of an arm of the transfer device that has transferred processed substrates, and to correct positions of the stages based on the amount of change of the arm of the transfer device. 
     According to an aspect of the present disclosure, it is possible to provide a substrate processing system, which includes a transfer device that simultaneously transfers a plurality of substrates and which is capable of suitably correcting positions of the substrates, and a method of controlling the substrate processing system. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a plan view showing an example of a substrate processing system according to a first embodiment. 
         FIG. 2  is a schematic cross-sectional view showing an example of a process chamber included in the substrate processing system according to the first embodiment. 
         FIG. 3A  is an example of a schematic cross-sectional view of a load lock chamber LLM. 
         FIG. 3B  is an example of a plan view of a load lock chamber LLM 1 . 
         FIG. 3C  is an example of a plan view of a load lock chamber LLM 2 . 
         FIG. 4  is a flow chart for explaining transfer of a substrate by the substrate processing system according to the first embodiment. 
         FIG. 5A  is an example of a longitudinal sectional view for explaining operations of the load lock chambers of the substrate processing system according to the first embodiment. 
         FIG. 5B  is an example of a longitudinal sectional view for explaining operations of the load lock chambers of the substrate processing system according to the first embodiment. 
         FIG. 5C  is an example of a longitudinal sectional view for explaining operations of the load lock chambers of the substrate processing system according to the first embodiment. 
         FIG. 5D  is an example of a longitudinal sectional view for explaining operations of the load lock chambers of the substrate processing system according to the first embodiment. 
         FIG. 6A  is an example of a longitudinal sectional view for explaining operations of the load lock chambers of the substrate processing system according to the first embodiment. 
         FIG. 6B  is an example of a longitudinal sectional view for explaining operations of the load lock chambers of the substrate processing system according to the first embodiment. 
         FIG. 7  is a plan view showing an example of a substrate processing system according to a second embodiment. 
         FIG. 8  is a plan view showing an example of a substrate processing system according to a third embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure will now be described with reference to the drawings. Throughout the drawings, the same constituent portions may be denoted by the same reference numerals, and redundant explanation thereof may be omitted. 
     &lt;Substrate Processing System&gt; 
     An example of a substrate processing system according to a first embodiment will be described with reference to  FIG. 1 .  FIG. 1  is a plan view showing an example of the substrate processing system according to the first embodiment.  FIG. 1  shows a state in which substrates W such as semiconductor wafers are loaded into a process chamber PM 1 . Further, a state in which the substrates W are unloaded from a load lock chamber LLM is indicated by a two-dot chain line. Further, the substrates W are shown with dot-hatching. 
     The substrate processing system shown in  FIG. 1  is a system having a cluster structure (multi-chamber type). The substrate processing system includes process chambers (process modules) PM 1  to PM 4 , a transfer chamber (vacuum transfer module) VTM, a load lock chamber (load lock module) LLM, loader modules LM 1  and LM 2 , load ports LP 1  to LP 4 , and a controller  900 . 
     The process chambers PM 1  to PM 4  are depressurized to a predetermined vacuum atmosphere and perform desired processes (an etching process, a film-forming process, a cleaning process, an ashing process, and the like) for the substrates W inside the process chambers PM 1  to PM 4 . The process chambers PM 1  to PM 4  are disposed adjacent to the transfer chamber VTM. The process chambers PM 1  to PM 4  are in communication with the transfer chamber VTM by opening/closing gate valves GV 1  to GV 4 , respectively. The process chamber PM 1  has a stage S on which a total of four substrates W are placed in a 2×2 matrix in a plan view. Similarly, each of the process chambers PM  2  to PM 4  has a stage S on which four substrates W are placed. Operations of individual components for processing in the process chambers PM 1  to PM 4  are controlled by the controller  900 . 
     The transfer chamber VTM is depressurized to a predetermined vacuum atmosphere. Further, a transfer device ARM 1  for transferring the substrates W is provided inside the transfer chamber VTM. The transfer device ARM 1  loads and unloads the substrates W between the process chambers PM 1  to PM 4  and the transfer chamber VTM according to opening and closing of the gate valves GV 1  to GV 4 . Further, the transfer device ARM 1  loads and unloads the substrates W between the load lock chamber LLM and the transfer chamber VTM according to opening and closing of a gate valve GV 5 . Operations of the transfer device ARM 1  and the opening and closing of the gate valves GV 1  to GV 5  are controlled by the controller  900 . 
     The transfer device ARM 1  is configured as an articulated arm including a base  210 , a first link  220 , a second link  230 , and an end effector  240 . One end portion of the first link  220  is rotably attached to the base  210  with a vertical direction as a rotation axis. Further, the base  210  can move the first link  220  upward and downward in the vertical direction. One end portion of the second link  230  is rotably attached to the other end portion of the first link  220  with the vertical direction as a rotation axis. A base end portion of the end effector  240  is rotably attached to the other end portion of the second link  230  with the vertical direction as a rotation axis. A plurality of holders for holding substrates W is provided on a leading end portion of the end effector  240 . Actuators that drive the upward and downward movement of the first link  220 , a joint between the base  210  and the first link  220 , a joint between the first link  220  and the second link  230 , and a joint between the second link  230  and the end effector  240  are controlled by the controller  900 . 
     The end effector  240  is formed in a fork shape having a branching leading end portion, and has a base end portion  241  and two sets of forks  242  and  243  extending from the base end portion  241 . The fork  242  has two blades  242   a  and  242   b . Similarly, the fork  243  has two blades  243   a  and  243   b . The four blades  242   a ,  242   b ,  243   a , and  243   b  extend in the same direction from the base end portion  241  and are formed at the same height. The fork  242  holds a substrate W such that the substrate W bridges between the blade  242   a  and the blade  242   b . Further, the fork  242  holds two substrates W along a longitudinal direction of the blades  242   a  and  242   b . Similarly, the fork  243  holds a substrate W such that the substrate W bridges between the blade  243   a  and the blade  243   b . Further, the fork  243  holds two substrates W along a longitudinal direction of the blades  243   a  and  243   b . As described above, the transfer device ARM 1  is configured to be capable of transferring the four substrates W at the same time. 
     The load lock chamber LLM is provided between the transfer chamber VTM and the loader modules LM 1  and LM 2 . The load lock chamber LLM is configured to be capable of switching between atmospheric atmosphere and a vacuum atmosphere. The load lock chamber LLM and the transfer chamber VTM of the vacuum atmosphere are in communication with each other by opening and closing the gate valve GV 5 . The load lock chamber LLM and the loader module LM 1  of atmospheric atmosphere are in communication with each other by opening and closing a gate valve GV 6 . The load lock chamber LLM and the loader module LM 2  of atmospheric atmosphere are in communication with each other by opening and closing a gate valve GV 7 . The load lock chamber LLM has a stage on which a total of four substrates W are placed in a 2×2 matrix in a plan view. The switching between the vacuum atmosphere and atmospheric atmosphere in the load lock chamber LLM is controlled by the controller  900 . 
     As shown in  FIGS. 3A to 3C  which will be described later, the load lock chamber LLM is provided with two chambers in the vertical direction, that is, a load lock chamber LLM 1  and a load lock chamber LLM 2 . Further, the gate valves GV 5  (gate valves GV 51  and GV 52 ) are provided independently in the respective of the load lock chambers LLM 1  and LLM 2 , and can be opened and closed independently from each other. Similarly, the valves GV 6  and GV 7  (valves GV 61 , GV 62 , GV 71 , and GV 72 ) are provided independently in the respective of the load lock chambers LLM 1  and LLM 2 , and can be opened and closed independently from one another. 
     The loader modules LM 1  and LM 2  have atmospheric atmosphere and, for example, downflow of clean air is formed therein. Further, a transfer device ARM 2  for transferring substrates W is provided inside the loader module LM 1 . The transfer device ARM 2  loads and unloads the substrates W between the load lock chamber LLM and the loader module LM 1  according to the opening and closing of the gate valve GV 6 . Similarly, a transfer device ARM 3  for transferring substrates W is provided inside the loader module LM 2 . The transfer device ARM 3  loads and unloads the substrates W between the load lock chamber LLM and the loader module LM 2  according to the opening and closing of the gate valve GV 7 . Further, a delivery part (not shown) on which substrates W are placed is provided below the load lock chamber LLM. The transfer devices ARM 2  and ARM 3  can deliver the substrates W via the delivery part. Operations of the transfer devices ARM 2  and ARM 3  and the opening and closing of the gate valves GV 6  and GV 7  are controlled by the controller  900 . 
     The transfer device ARM 2  is configured as an articulated arm including a base  410 , a first link  420 , a second link  430 , and an end effector  440 . One end portion of the first link  420  is rotably attached to the base  410  with the vertical direction as a rotation axis. Further, the base  410  can move the first link  420  upward and downward in the vertical direction. One end portion of the second link  430  is rotably attached to the other end portion of the first link  420  with the vertical direction as a rotation axis. A base end portion of the end effector  440  is rotably attached to the other end portion of the second link  430  with the vertical direction as a rotation axis. A fork  441  for holding the substrate W is provided on a leading end portion of the end effector  440 . Actuators that drive the upward and downward movement of the first link  420 , a joint between the base  410  and the first link  420 , a joint between the first link  420  and the second link  430 , and a joint between the second link  430  and the end effector  440  are controlled by the controller  900 . The transfer device ARM 3  is configured as an articulated arm similar to the transfer device ARM 2 . 
     The load ports LP 1  and LP 2  are provided on a wall surface of the loader module LM 1 . Further, the load ports LP 3  and LP 4  are provided on a wall surface of the loader module LM 2 . A carrier C in which the substrate W is accommodated or an empty carrier C is provided in each of the load ports LP 1  to LP 4 . As the carrier C, for example, a front opening unified pod (FOUP) or the like can be used. 
     The transfer device ARM 2  can take out the substrates W accommodated in each of the load ports LP 1  and LP 2  while holding the substrates W with the fork  441  of the transfer device ARM 2 . Further, the substrates W held by the fork  441  can be accommodated in each of the load ports LP 1  and LP 2 . Similarly, the transfer device ARM 3  can take out the substrates W accommodated in each of the load ports LP 3  and LP 4  while holding the substrates W by a holding part of the transfer device ARM 3 . Further, the substrates W held by the holding part can be accommodated in each of the load ports LP 3  and LP 4 . 
     The controller  900  has a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD). The controller  900  may have other memory areas such as a solid state drive (SSD) without being limited to the HDD. A recipe in which process procedures, process conditions, and transfer conditions are set is stored in the memory area such as the HDD or RAM. 
     The CPU controls the processing for the substrate W in each process chamber PM and controls the transfer of the substrates W according to the recipe. A program for executing the processing for the substrates W in each process chamber PM and the transfer of the substrates W may be stored in the HDD or RAM. The program may be provided from a storage medium storing the program, or may be provided from an external device via a network. 
     &lt;Process Chamber&gt; 
     Next, the process chambers PM 1  to PM 4  will be further described with reference to  FIG. 2 .  FIG. 2  is a schematic cross-sectional view showing an example of the process chamber PM 1  included in the substrate processing system according to the first embodiment. The configurations of the process chambers PM 2  to PM 4  are the same as that of the process chamber PM 1 , and redundant explanation thereof will be omitted. Further, in  FIG. 2 , a case where the process chamber PM 1  is a plasma processing apparatus will be described as an example. 
     The process chamber PM 1  has a chamber  1 . The chamber  1  has a container  12  and a lid  11 . The container  12  and the lid  11  are formed of, for example, aluminum, and the lid  11  is provided at an opening of the bottomed container  12 . The chamber  1  and the lid  11  are sealed by an O-ring  13 . As a result, the interior of the chamber  1  can be sealed in a vacuum state. A film having corrosion resistance to plasma may be formed on inner walls of the container  12  and the lid  11 . The film may be ceramics such as aluminum oxide and yttrium oxide. 
     The container  12  is provided with four stages S, and  FIG. 2  shows two of the four stages. Each of the stages S is formed in a flat disk shape on which a substrate W is mounted. The stage S is formed of a dielectric material such as alumina (Al 2 O 3 ). A heater  20  for heating the substrate W is buried in the stage S. The heater  20  is composed of, for example, a ceramic sheet-shaped or plate-shaped resistance heating element and generates heat with power supplied from a power supply to heat the mounting surface of the stage S, so that the substrate W is heated to a predetermined process temperature suitable for film formation. For example, the heater  20  heats the substrate W placed on the stage S to 100 degrees C. to 300 degrees C. 
     The stage S has a support  22 , which extends downward from a center of a lower surface of the stage S and penetrates the bottom of the container  12 , with its one end supported by an elevating mechanism  35 . The elevating mechanism  35  raises and lowers the support  22  so that the stage S can move upward and downward between a processing position (the position shown in  FIG. 2 ) where the processing for the substrate W is performed and a delivery position where the transfer of the substrate W is performed. Further, the elevating mechanism  35  can adjust a distance (gap) between the stage S and an upper electrode  14 . 
     The delivery position is a position of the stage S shown by a two-dot chain line in  FIG. 2 . At this position, the substrate W is delivered to and from an external transfer mechanism via a loading/unloading port. The stage S is formed with through-holes through which shaft portions of lift pins  30  are inserted and penetrated. 
     In a state where the stage S is moved from the processing position (see  FIG. 2 ) of the substrate W to the delivery position of the substrate W, head portions of the lift pins  30  protrude from the mounting surface of the stage S. As a result, the head portions of the lift pins  30  support the substrate W from a lower surface of the substrate W, lift the substrate W upward from the mounting surface of the stage S, and deliver the substrate W to and from the external transfer mechanism. 
     Above the stages S and below the lid  11 , four upper electrodes  14  that also function as shower heads are provided to face the stages S, respectively. Each upper electrode  14  is formed of a conductor such as aluminum and has substantially a disk shape. The upper electrode  14  is supported by the lid  11 . A mesh-shaped metal electrode plate  21  is buried in the stage S in parallel with the heater  20 . As a result, the stage S also functions as a lower electrode facing the upper electrode  14 . 
     The upper electrode  14  is provided with a plurality of gas supply holes  16 . Under a control by a valve V and a flow rate controller MFC, a film-forming gas (reaction gas) of a predetermined flow rate output from a gas supply  15  is introduced into a gas introduction port  18  via a gas line  17  at a predetermined timing. The introduced gas is introduced from the plurality of gas supply holes  16  into the container  12  via a through-hole  19  formed in the lid  11  and a flow path  24  formed between an upper surface of the upper electrode  14  and the lid  11 . 
     Further, a radio-frequency (RF) power supply  36  is connected to each upper electrode  14  via a matching device  37 , and radio frequency power having a frequency of, for example, 0.4 MHz to 2,450 MHz is applied from the RF power supply  36  to the upper electrode  14 . The gas introduced into the container  12  is turned into plasma by the radio frequency power. The plasma generated in a space between the upper electrode  14  and the stage S causes the substrate W on the stage S to undergo a plasma process such as a film-forming process. 
     An annular member  40  formed of a dielectric material such as quartz is provided around the stage S so as to be separated from the stage S (see a gap  44  in  FIG. 2 ). Further, an exhaust manifold  41  is disposed on the annular member  40  and on an outer periphery of the upper electrode  14 . The annular member  40  and the exhaust manifold  41  are formed integral with each other and fixed to a side wall of the container  12  and the outer periphery of the upper electrode  14 . 
     The exhaust manifold  41  is formed of ceramics and has an exhaust path  42  in ae circumferential direction thereof. A gas that has passed through the exhaust path  42  passes through a plurality of exhaust ports  43  provided between the exhaust manifold  41  and the annular member  40 , passes under the stage S, flows toward the exhaust port  6  at the bottom of the container  12 , and is discharged from the exhaust port  6  to the outside of the chamber  1  by a vacuum pump  45 . Instead of the plurality of exhaust ports  43 , one exhaust port that is opened in the circumferential direction may be provided in the stage S. 
     Although the description has been made with an example in which one exhaust port  6  is provided at the bottom of the chamber  1 , the present disclosure is not limited thereto. For example, one or more exhaust ports  6  may be provided at a ceiling portion of the chamber  1 , and one or more exhaust ports  6  may be provided at a bottom portion and the ceiling portion of the chamber  1 . 
     The process chamber PM 1  may further include a controller  50 . The controller  50  may be a computer including a processor, a storage such as a memory, an input device, a display device, a signal input/output interface, and the like. The controller  50  controls individual components of the process chamber PM 1 . In the controller  50 , an operator can use the input device to perform a command input operation or the like in order to manage the process chamber PM 1 . Further, the controller  50  can cause the display device to visualize and display an operating status of the process chamber PM 1 . Further, a control program and recipe data are stored in the storage. The control program is executed by the processor in order to execute various processes in the process chamber PM 1 . The processor executes the control program to control individual components of the process chamber PM 1  according to the recipe data. 
     The controller  900  (see  FIG. 1 ) controls the operation of the process chamber PM 1  by instructing the controller  50 . With such a configuration, the process chamber PM 1  performs a desired process (for example, a film-forming process) for the substrate W placed on the stage S. 
     Although the case where the process chamber PM 1  is a plasma processing apparatus has been described as an example, the present disclosure is not limited thereto. The process chamber PM 1  can be applied to any type of, for example, thermal chemical vapor deposition (CVD) apparatus, plasma CVD apparatus, thermal atomic layer deposition (ALD) apparatus, plasma ALD apparatus, capacitively coupled plasma (CCP), inductively coupled plasma (ICP), radial line slot antenna, electron cyclotron resonance plasma (ECR), and helicon wave plasma (HWP). Further, the processing of the substrate W in the process chamber PM 1  is not limited to the film-forming process. The processing of the substrate W in the process chamber PM 1  may be, for example, an etching process, a cleaning process, an ashing process, or the like. 
     &lt;Load Lock Chamber&gt; 
     Next, the load lock chamber LLM will be further described with reference to  FIGS. 3A to 3C .  FIGS. 3A to 3C  are schematic views showing an example of the load lock chamber LLM included in the substrate processing system according to the first embodiment.  FIG. 3A  is an example of a schematic cross-sectional view of the load lock chamber LLM.  FIG. 3B  is an example of a plan view of the load lock chamber LLM 1 .  FIG. 3C  is an example of a plan view of the load lock chamber LLM 2 . In these figures, description will be given with horizontal directions as an x-axis and a y-axis and a height direction as a z-axis. 
     As shown in  FIG. 3A , the load lock chamber LLM includes the load lock chamber LLM 1  and the load lock chamber LLM 2 . Here, description will be made on a case where the load lock chamber LLM 1  is disposed in an upper stage and the load lock chamber LLM 2  is disposed in a lower stage, but the arrangement relationship thereof is not limited thereto. For example, the load lock chamber LLM 1  may be disposed in the lower stage and the load lock chamber LLM 2  may be disposed in the upper stage. Further, the load lock chamber LLM 1  and the load lock chamber LLM 2  may be arranged horizontally. 
     The load lock chamber LLM 1  has four magnetic levitation stages  310  on which unprocessed substrates W are placed. Each magnetic levitation stage  310  is configured so that its position can be adjusted in the x-axis direction and the y-axis direction with the unprocessed substrate W placed thereon. For example, the magnetic levitation stage  310  has a permanent magnet (not shown), and a pedestal  311  has a magnetic field generator (not shown) that generates a magnetic field. The position of the magnetic levitation stage  310  is controlled by controlling the magnetic field generator by the controller  900 . A width Ws of the magnetic levitation stage  310  is smaller than a width Wa of the fork  242  (a width between the blades  242   a  and  242   b ). 
     The load lock chamber LLM 2  has four fixed stages  320  on which processed substrates W are placed. A total of four substrates W are placed in a 2×2 matrix in a plan view in the fixed stages  320 , similarly to the stages S of the process chambers PM 1  to PM 4 . Further, each fixed stage  320  has lift pins  321  that support and lift up the substrate W from a back surface thereof. Raising and lowering of the lift pins  321  is controlled by the controller  900 . 
     By providing the load lock chamber LLM 2  having the fixed stages  320  in addition to the load lock chamber LLM 1  having the magnetic levitation stages  310 , it is possible to prevent processed substrates W having high temperatures from being placed on the magnetic levitation stages  310 . This prevents the permanent magnets of the magnetic levitation stages  310  from being thermally demagnetized. Further, by placing the processed substrates W on the fixed stages  320 , the heat of the processed substrates W can be dissipated to the fixed stages  320  to cool the substrates W. 
     Further, the substrate processing system includes an elongation amount sensor  350  that detects an elongation amount (change amount) of the transfer device ARM 1 . In the transfer device ARM 1  for transferring the substrate between the load lock chambers LLM 1  and LLM 2  and the process chambers PM 1  to PM 1 , for example, the first link  220 , the second link  230 , the end effector  240 , and the like are thermally elongated due to the heat of the process chambers PM 1  to PM 4 . The elongation amount sensor  350  is provided in, for example, the load lock chamber LLM 2  and detects the elongation amount of the transfer device ARM 1  when the processed substrate W is returned from the process chambers PM 1  to PM 4  to the load lock chamber LLM 2 . For example, when the transfer device ARM 1  is controlled to be located at a teaching position for delivering the processed substrate W to the fixed stage  320 , the elongation amount of the transfer device ARM 1  is detected by detecting a position of a marker (not shown) of the end effector  240 . A method of detecting the elongation amount of the transfer device ARM 1  by the elongation amount sensor  350  is not limited thereto, and various methods can be used to detect the elongation amount of the transfer device ARM 1 . Further, the position of the elongation amount sensor  350  is not limited thereto. For example, the elongation amount sensor  350  may be provided in the transfer chamber VTM. 
     &lt;Substrate Transfer Control&gt; 
     Next, in the substrate processing system according to the first embodiment, control suitable for transferring the substrate W to the stages S of the process chambers PM 1  to PM 4  will be described with reference to  FIGS. 4, 5A to 5D, and 6A and 6B .  FIG. 4  is a flow chart for explaining transfer of the substrate by the substrate processing system according to the first embodiment.  FIGS. 5A to 5D and 6A and 6B  are examples of longitudinal sectional views for explaining operations of the load lock chamber LLM of the substrate processing system according to the first embodiment. 
     In step S 1 , as shown in  FIG. 5A , unprocessed substrates W are loaded into the load lock chamber LLM 1 . That is, the controller  900  opens the gate valves GV 61  and GV 71 . The controller  900  controls the transfer devices ARM 2  and ARM 3  to take out the unprocessed substrates W from the carrier C of the load port LP and place the unprocessed substrates W on the magnetic levitation stage  310 . When four unprocessed substrates W are placed on the magnetic levitation stages  310  of the load lock chamber LLM 1  and the transfer devices ARM 2  and ARM 3  retract from the load lock chamber LLM 1 , the controller  900  closes the gate valves GV 61  and GV 71 . The controller  900  controls an exhaust device (not shown) of the load lock chamber LLM 1  to exhaust air in the load lock chamber LLM 1  so that the load lock chamber LLM 1  is switched from atmospheric atmosphere to the vacuum atmosphere. 
     In step S 2 , the processed substrates W processed in the process chamber PM 1  is unloaded from the process chamber PM 1 . That is, the controller  50  controls the elevating mechanisms  35  to lower the stages S and supports the processed substrates W with the lift pins  30 . The controller  900  opens the gate valve GV 1 . The controller  900  controls the transfer device ARM 1  to allow the forks  242  and  243  to enter the process chamber PM 1  and move them to the teaching position. The controller  900  controls the transfer device ARM 1  to raise the forks  242  and  243  from the teaching position, thereby delivering the processed substrates W from the lift pins  30  to the forks  242  and  243 . The controller  900  controls the transfer device ARM 1  to unload the processed substrates W held by the forks  242  and  243  from the process chamber PM 1 . The controller  900  closes the gate valve GV 1 . 
     In step S 3 , as shown in  FIG. 5B , the processed substrates W are loaded into the load lock chamber LLM 2 . That is, the controller  900  opens the gate valve GV 52 . The controller  900  controls the transfer device ARM 1  to allow the forks  242  and  243  holding the processed substrates W to enter the process chamber PM 1  and move them to the teaching position. 
     In step S 4 , the elongation amount of the transfer device ARM 1  is measured. That is, the controller  900  measures the elongation amount of the transfer device ARM 1  based on a value detected by the elongation amount sensor  350 . Thereafter, the controller  900  raises the lift pins  321  and delivers the processed substrates W from the forks  242  and  243  to the lift pins  321 . The controller  900  controls the transfer device ARM 1  to retract the forks  242  and  243  from the load lock chamber LLM 2 . The controller  900  closes the gate valve GV 52 . The controller  900  lowers the lift pins  321  and places the processed substrates W on the fixed stages  320 . As a result, the heat of the processed substrates W is dissipated to the fixed stages  320  to cool the processed substrates W. 
     In step S 5 , the controller  900  calculates stage correction amounts. Here, there is a machine difference in the arrangement relationship of the four stages S in the process chambers PM 1  to PM 4 . The controller  900  calculates correction amounts of the magnetic levitation stages  310  on which the unprocessed substrates W are placed, based on information on the machine difference regarding the arrangement relationship of the stages S in a next process chamber PM into which the substrates W are loaded and the elongation amount of the transfer device ARM 1  measured in step S 4 . 
     In step S 6 , as shown in  FIG. 5C , the controller  900  corrects positions of the magnetic levitation stages  310  based on the calculated stage correction amounts. 
     In step S 7 , unprocessed substrates W are unloaded from the load lock chamber LLM 1 . That is, the controller  900  opens the gate valve GV 51 . As shown in  FIG. 5D , the controller  900  controls the transfer device ARM 1  to allow the forks  242  and  243  to enter the load lock chamber LLM 1  and move them to the teaching position. At this time, as described above with reference to  FIG. 3B , the width Wa of the fork  242  (the width between the blades  242   a  and  242   b ) is sufficiently larger than the width Ws of the magnetic levitation stages  310 , so that the fork  242  and the magnetic levitation stages  310  are configured so as not to come into contact with one another even after the positions of the magnetic levitation stages  310  are corrected. Subsequently, as shown in  FIG. 6A , the controller  900  controls the transfer device ARM 1  to raise the forks  242  and  243  from the teaching position to deliver the unprocessed substrates W from the magnetic levitation stages  310  to the forks  242  and  243 . As shown in  FIG. 6B , the controller  900  controls the transfer device ARM 1  to unload the unprocessed substrates W held by the forks  242  and  243  from the load lock chamber LLM 1 . The controller  900  closes the gate valve GV 51 . 
     In step S 8 , the unprocessed substrates W are loaded into the process chamber PM 1 . That is, the controller  900  opens the gate valve GV 1 . The controller  900  controls the transfer device ARM 1  to allow the forks  242  and  243  holding the unprocessed substrates W to enter the process chamber PM 1  and move them to the teaching position. The controller  900  controls the transfer device ARM 1  to lower the forks  242  and  243  from the teaching position, thereby delivering the unprocessed substrates W from the forks  242  and  243  to the lift pins  30 . The controller  900  controls the transfer device ARM 1  to retract the forks  242  and  243  from the process chamber PM 1 . The controller  900  closes the gate valve GV 1 . The controller  50  controls the elevating mechanisms  35  to raise the stages S and place the unprocessed substrates W on the stages S. Then, the controller  50  performs a desired process on the substrates W. 
     In step S 9 , the processed substrates W are unloaded from the load lock chamber LLM 2 . That is, the controller  900  controls an exhaust device (not shown) of the load lock chamber LLM 2  to switch the load lock chamber LLM 2  from the vacuum atmosphere to atmospheric atmosphere. The controller  900  opens the gate valves GV 62  and GV 72 . The controller  900  raises the lift pins  321  to lift up the processed substrates W placed on the fixed stages  320 . The controller  900  controls the transfer devices ARM 2  and ARM 3  to take out the processed substrates W from the load lock chamber LLM 2  and store them in the carrier C of the load port LP. When four processed substrates W are unloaded from the load lock chamber LLM 2  and the transfer devices ARM 2  and ARM 3  are retracted from the load lock chamber LLM 2 , the controller  900  closes the gate valves GV 62  and GV 72 . 
     In the flow chart shown in  FIG. 4 , the process of step S 9  is performed after the process of step S 8 , but the present disclosure is not limited thereto. From the viewpoint of throughput, it is desirable to carry out the process of step S 9  in parallel with the process of any of step S 4  (after closing the gate valve GV 52 ) to step S 8 . Similarly, with respect to the process of step S 1 , the process of step S 1  may be performed in parallel with the process of any of step S 2  to step S 5  from the viewpoint of throughput. 
     As described above, according to the substrate processing system according to the first embodiment, a plurality of substrates W can be simultaneously transferred to the process chambers PM 1  to PM 4  in consideration of the machine difference in the arrangement of the stage S of the process chambers PM 1  to PM 4  and the thermal elongation (change amount) of the transfer device ARM 1 . As a result, the substrates W can be transferred to a desirable position of the stage S of the process chambers PM 1  to PM 4 . 
     Further, the stage of the load lock chamber LLM 1  may be a stage driven by a motor. By using the magnetic levitation stage  310 , it is possible to suppress generation of particles and the like due to friction and the like as compared with the motor drive configuration. As a result, it is possible to prevent particles and the like from adhering to the substrate W. 
     Further, for example, the transfer devices ARM 1  to ARM 3  are driven by a motor capable of controlling a rotation angle to control the position of the forks. The minimum unit (step angle) of the rotation angle that can be controlled is defined according to the structure of the motor. Therefore, in the position control by the transfer devices ARM 1  to ARM 3 , the resolution of the position control is defined according to the characteristics of the motor. In contrast, the magnetic levitation stage  310  can have a higher resolution of the position control than the motor. As a result, accuracy in position alignment when the substrate W is placed on the stages S of the process chambers PM 1  to PM 4  can be improved. 
     Further, in the substrate processing system according to the first embodiment, the position alignment based on the machine difference of the process chambers PM 1  to PM 4  is performed in steps S 5  and S 6 . In contrast, in a conventional method, it is necessary to perform such position alignment based on the machine difference of the process chambers PM 1  to PM 1  when the substrate W is loaded into the load lock chamber LLM 1 . Therefore, when it becomes necessary to transfer a substrate W, which was originally planned to be transferred to the process chamber PM 1 , to the process chamber PM 2  first due to, for example, a trouble in the process chamber PM 1 , it is required that the load lock chamber LLM 1  is returned from the vacuum atmosphere to atmospheric atmosphere, the gate valves GV 61  and GV 71  are opened, position adjustment is performed again in the transfer devices ARM 2  and ARM 3 , the gate valves GV 61  and GV 71  are closed, and the load lock chamber LLM 1  is returned from atmospheric atmosphere to the vacuum atmosphere. Thus, the processing time becomes long. In contrast, in the substrate processing system according to the first embodiment, since the position adjustment can be performed while maintaining the load lock chamber LLM 1  at the vacuum atmosphere, the processing time can be shortened. 
     Next, an example of a substrate processing system according to a second embodiment will be described with reference to  FIG. 7 .  FIG. 7  is a plan view showing an example of the substrate processing system according to the second embodiment. The substrate processing system according to the second embodiment has an alignment device  500  as compared with the substrate processing system according to the first embodiment. The alignment device  500  includes four magnetic levitation stages  310  and a pedestal  311 , similar to the load lock chamber LLM 1 . 
     According to the substrate processing system according to the second embodiment, for example, in a case of a configuration in which substrates W are processed in the process chamber PM 1  and then are further processed in the process chamber PM 2 , the substrates W are transferred from the load lock chamber LLM 1  to the alignment device  500 , and correction according to the machine difference of the process chamber PM 1  and the thermal elongation amount of the transfer device ARM 1  is performed in the alignment device  500 . Then, the substrates W are transferred to the process chamber PM 1 . After the substrates W is processed in the process chamber PM 1 , the substrates W are transferred from the process chamber PM 1  to the alignment device  500 , and correction according to the machine difference of the process chamber PM 2  and the thermal elongation amount of the transfer device ARM 1  is performed in the alignment device  500 . Then, the substrates W can be transferred to the process chamber PM 2 . 
     Next, an example of a substrate processing system according to a third embodiment will be described with reference to  FIG. 8 .  FIG. 8  is a plan view showing an example of the substrate processing system according to the third embodiment. In comparison with the substrate processing system according to the first embodiment, the substrate processing system according to the third embodiment includes a pass module  600  that connects a module M 1 , which is composed of process chambers PM 1  to PM 4 , a transfer device ARM 1 , and a transfer chamber VTM 1 , and a module M 2 , which is composed of process chambers PM 11  to PM 14 , a transfer device ARM 11 , and a transfer chamber VTM 2 . The pass module  600  includes four magnetic levitation stages  310  and a pedestal  311 , similar to the load lock chamber LLM 1 . 
     According to the substrate processing system according to the third embodiment, for example, in a case of a configuration in which substrates W are processed in the process chamber PM 1  and then are further processed in the process chamber PM 11 , the substrates W are transferred from the load lock chamber LLM 1  to the pass module  600 , and correction according to the machine difference of the process chamber PM 1  and the thermal elongation amount of the transfer device ARM 1  is performed in the pass module  600 . Then, the substrates W are transferred to the process chamber PM 1 . After the substrates W are processed in the process chamber PM 1 , the substrates W are transferred from the process chamber PM 1  to the pass module  600 , and correction according to the machine difference of the process chamber PM 11  and the thermal elongation amount of the transfer device ARM 11  is performed in the pass module  600 . Then, the substrates W can be transferred to the process chamber PM 11 . 
     Although the embodiments of the substrate processing system according to the first to third embodiments have been described above, the present disclosure is not limited to the above embodiments and the like, and various modifications and improvements can be made without departing from the spirit and scope of the present disclosure set forth in the claims. 
     This application claims priority based on Japanese Patent Application No. 2019-099729, filed on May 28, 2019, the entire contents of which are incorporated herein by reference. 
     EXPLANATION OF REFERENCE NUMERALS 
       310 : magnetic levitation stage,  311 : pedestal,  320 : fixed stage,  321 : lift pin,  900 : controller, PM 1  to PM 4 : process chamber, VTM: transfer chamber, ARM 1 : transfer device, LLM 1  and LLM 2 : load lock chamber, LM 1  and LM 2 : loader module, LP 1  to LP 4 : load port, GV 1  to GV 7 : gate valve, C: carrier