Abstract:
Provided is a substrate processing device capable of improving throughput without increasing the operation speed of a drive device. Vacuum processing chambers which house a wafer for plasma processing of the wafer are respectively provided with gate valves for opening and closing a wafer inlet/outlet port, and wafer detection sensors for detecting the wafer moving forward or backward through the wafer inlet/outlet port, and a scara robot for making extending/retracting motion and rotating motion transfers the wafer. At this time, the scara robot starts the rotating motion to transfer the wafer picked up from the vacuum processing chamber in response to a trigger signal transmitted from the wafer detection sensor. The trigger signal indicates that the wafer has passed through the wafer inlet/outlet port and has arrived at a point where the gate valve and the wafer inlet/outlet port no longer interfere with the wafer.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to a substrate processing apparatus and a substrate transfer method in a substrate processing apparatus. 
       BACKGROUND 
       [0002]    As a plasma processing apparatus for performing a plasma process on substrates such as semiconductor wafers, an apparatus including: a loader module maintained in an atmospheric pressure environment to load and unload semiconductor wafers into and from a FOUP that is a container having a plurality of semiconductor wafers accommodated therein between a load port for mounting the FOUP and a processing module (vacuum processing chamber) for performing a plasma process on semiconductor wafers; a transfer module maintained in a vacuum environment to load and unload semiconductor wafers into and from the processing module; and a load lock module disposed between the loader module and the transfer module and being selectively switchable between the atmospheric pressure environment and the vacuum environment has been used. In such a plasma processing apparatus, a first wafer transfer unit is disposed in the loader module, and a second wafer transfer unit is disposed in the transfer module. The wafer transfer units transfer semiconductor wafers between the load port and the processing module. 
         [0003]    As the wafer transfer unit, a unit configured to have an extendable arm and be entirely rotatable has been used. In such a wafer transfer unit, an operation of the wafer transfer unit is controlled based on detection information obtained by individually detecting, using sensors, information on a rotating operation, an extending/contracting operation of the extendable arm, information on the presence or not of a semiconductor wafer on the extendable arm, information on an opening/closing operation of gate values between the respective modules, and the like. 
         [0004]    Specifically, after the contracting operation of the extendable arm holding a semiconductor wafer taken out from a vacuum transfer chamber is terminated, the wafer transfer unit initiates a transfer operation of the held semiconductor wafer toward the load lock module. Also, the closing operation of a gate valve for allowing the vacuum transfer chamber to be isolated from and communicate with the transfer module is initiated after the information on the contracting operation of the extendable arm and the presence or not of the semiconductor wafer is confirmed (e.g., see Patent Document 1). 
       PRIOR ART DOCUMENT   
     Patent Documents 
       [0005]    Japanese Laid-Open Patent Publication No. (Sho) 64-48443 
         [0006]    In order to improve a mechanical throughput of a wafer transfer system in the plasma processing apparatus described above, it is necessary to reduce the opening/closing operation time of the gate valve or the operation time of the wafer transfer unit. In order to solve this problem, the operation speed of the gate valve or the wafer transfer unit may be increased. However, when the operation speed of various drive units is increased, problems occur from the generation of vibration, deterioration of accuracy, an increase in oscillation, and the like. Hence, the realization thereof is not easy. 
       SUMMARY 
       [0007]    The present disclosure provides some embodiments of a substrate processing apparatus and a substrate transfer method, which are capable of improving throughput without increasing the operation speed of a drive unit. 
         [0008]    In order to solve the above-described problems, according to one embodiment of the present disclosure, there is provided a substrate processing apparatus, including: a plurality of substrate processing units each including a chamber configured to accommodate a substrate therein, an opening/closing member configured to open and close a substrate loading/unloading port of the chamber, and a substrate detection sensor configured to detect a substrate advanced or retreated through the substrate loading/unloading port, the plurality of substrate processing units each performing a predetermined process on the substrate in the chamber; a transfer unit configured to perform a rotating operation and/or a sliding operation for selectively accessing the plurality of substrate processing units and an extending/contracting operation for loading and unloading the substrate into and from the chamber of the accessed substrate processing unit; and a control unit configured to control operations of the substrate processing units and the transfer unit, wherein, in response to a signal received from the substrate detection sensor as a trigger, which indicates that a substrate extracted from one chamber of the plurality of substrate processing units by the extending/contracting operation of the transfer unit passes through a substrate loading/unloading port of the one chamber and arrives at a position where the substrate does not interfere with the opening/closing member and the substrate loading/unloading port, the control unit allows the transfer unit to initiate the rotating operation or the sliding operation for transferring the substrate extracted from the one chamber into another chamber of the plurality of substrate processing units. 
         [0009]    In the present disclosure, the control unit allows the transfer unit to initiate the rotating operation or the sliding operation so that the substrate extracted from the one chamber is transferred into the other chamber and the control unit simultaneously initiates a closing operation of the opening/closing member so that the substrate loading/unloading port of the one chamber is closed. 
         [0010]    In the present disclosure, the control unit allows the transfer unit to initiate the rotating operation or the sliding operation so that the substrate extracted from the one chamber is transferred into the other chamber and the control unit simultaneously initiates an opening operation of the opening/closing member so that the substrate loading/unloading port of the other chamber is opened. 
         [0011]    In the present disclosure, the control unit detects a positional deviation of the substrate transferred by the transfer unit based on a signal from the substrate detection sensor, and when the positional deviation of the substrate is generated, the control unit controls at least one of the extending/contracting operation, the rotating operation and the sliding operation of the transfer unit so that the positional deviation is corrected. 
         [0012]    In order to solve the above-described problems, according to another embodiment of the present disclosure, there is provided a substrate processing apparatus, including: at least one substrate processing unit including a chamber configured to accommodate a substrate therein, an opening/closing member configured to open and close a substrate loading/unloading port of the chamber, and a substrate detection sensor configured to detect a substrate advanced or retreated through the substrate loading/unloading port, at least one substrate processing unit performing a predetermined process on the substrate in the chamber; a transfer unit including at least two arms respectively configured to hold the substrate and be independently extendable and contractible, the transfer unit being configured to perform a rotating operation and/or a lifting operation for loading and unloading a substrate into and from the chamber; and a control unit configured to control operations of the transfer unit, wherein, in response to a signal received from the substrate detection sensor as a trigger, which indicates that a substrate extracted from the chamber by one of the at least two arms passes through the substrate loading/unloading port of the chamber and arrives at a position where the substrate does not interfere with the opening/closing member and the substrate loading/unloading port, the control unit allows the transfer unit to initiate the rotating operation or the lifting operation for loading a substrate held by the other of the at least two arms into the chamber. 
         [0013]    In the present disclosure, the control unit detects a positional deviation of the substrate transferred by the transfer unit based on a signal from the substrate detection sensor, and when the positional deviation of the substrate is generated, the control unit controls at least one of the extending/contracting operation, the rotating operation and the lifting operation of the transfer unit so that the positional deviation is corrected. 
         [0014]    In order to solve the above-described problems, according to another embodiment of the present disclosure, there is provided a substrate processing apparatus, including: a substrate processing unit including a chamber configured to accommodate a substrate therein, the substrate processing unit performing a predetermined process on the substrate in the chamber; a substrate accommodating chamber configured to accommodate the substrate therein to load a substrate to be processed in the substrate processing unit from the outside and to unload a substrate which has been processed in the substrate processing unit to the outside; a chamber opening/closing member configured to open and close a substrate loading/unloading port of the chamber; a first opening/closing member configured to open and close a first substrate loading/unloading port of the substrate accommodating chamber; a first transfer unit configured to perform a rotating operation and/or a sliding operation and an extending/contracting operation for selectively accessing the substrate processing unit and the substrate accommodating chamber; a first substrate detection sensor configured to detect a substrate held by the first transfer unit to be advanced and retreated through the first substrate loading/unloading port; a second substrate detection sensor configured to detect a substrate held by the first transfer unit to be advanced and retreated through the substrate loading/unloading port of the chamber; and a control unit configured to control opening/closing operations of the chamber opening/closing member and the first opening/closing member and an operation of the first transfer unit, wherein, in response to a signal received from the first substrate detection sensor as a trigger, which indicates that a substrate extracted from the substrate accommodating chamber by the extending/contracting operation of the first transfer unit passes through the first substrate loading/unloading port and arrives at a position where the substrate does not interfere with the first opening/closing member and the first substrate loading/unloading port, the control unit allows the first transfer unit to initiate the rotating operation or the sliding operation for transferring the substrate extracted from the substrate accommodating chamber into the chamber; and, in response to a signal received from the second substrate detection sensor as a trigger, which indicates that a substrate extracted from the chamber by the extending/contracting operation of the first transfer unit passes through the substrate loading/unloading port of the chamber and arrives at a position where the substrate does not interfere with the chamber opening/closing member and the substrate loading/unloading port of the chamber, the control unit allows the first transfer unit to initiate the rotating operation or the sliding operation for transferring the substrate extracted from the chamber into the substrate accommodating chamber. 
         [0015]    In the present disclosure, the control unit allows the first transfer unit to initiate the rotating operation or the sliding operation so that the substrate extracted from the substrate accommodating chamber is transferred into the chamber and the control unit simultaneously initiates the closing operation of the first opening/closing member so that the first substrate loading/unloading port of the substrate accommodating chamber is closed; and the control unit allows the first transfer unit to initiate the rotating operation or the sliding operation so that the substrate extracted from the chamber is transferred into the substrate accommodating chamber and the control unit simultaneously initiates the closing operation of the chamber opening/closing member so that the substrate loading/unloading port of the chamber is closed. 
         [0016]    In the present disclosure, the control unit allows the first transfer unit to initiate the rotating operation or the sliding operation so that the substrate extracted from the substrate accommodating chamber is transferred into the chamber and the control unit simultaneously initiates the opening operation of the chamber opening/closing member so that the substrate loading/unloading port of the chamber is opened; and the control unit allows the first transfer unit to initiate the rotating operation or the sliding operation so that the substrate extracted from the chamber is transferred into the substrate accommodating chamber and the control unit simultaneously initiates the opening operation of the first opening/closing member so that the first substrate loading/unloading port is opened. 
         [0017]    In the present disclosure, the control unit detects a positional deviation of the substrate transferred by the first transfer unit based on signals from the first and second substrate detection sensors, and when the positional deviation of the substrate is generated, the control unit controls at least one of the extending/contracting operation, the rotating operation and the sliding operation of the first transfer unit so that the positional deviation is corrected. 
         [0018]    In order to solve the above-described problems, according to another embodiment of the present disclosure, there is provided a substrate processing apparatus, including: a substrate processing unit including a chamber configured to accommodate a substrate therein, the substrate processing unit performing a predetermined process on the substrate in the chamber; a substrate accommodating chamber configured to accommodate the substrate therein to load a substrate to be processed in the substrate processing unit from the outside and to unload a substrate which has been processed in the substrate processing unit to the outside; a first opening/closing member configured to open and close a first substrate loading/unloading port of the substrate accommodating chamber; a first transfer unit including at least two arms respectively configured to hold the substrate and be independently extendable and contractible, the first transfer unit being configured to perform a rotating operation or a lifting operation for loading and unloading a substrate into and from the chamber and the substrate accommodating chamber using the arms; a first substrate detection sensor configured to detect a substrate advanced and retreated through the first substrate loading/unloading port by the first transfer unit; and a control unit configured to control operations of the first transfer unit, wherein in response to a signal received from the first substrate detection sensor as a trigger, which indicates that a substrate extracted from the substrate accommodating chamber by one of the at least two arms passes through the first substrate loading/unloading port and arrives at a position where the substrate does not interfere with the first opening/closing member and the first substrate loading/unloading port, the control unit allows the first transfer unit to initiate the rotating operation or the lifting operation for loading a substrate held by the other of the at least two arms into the substrate accommodating chamber. 
         [0019]    In the present disclosure, the control unit detects a positional deviation of the substrate transferred by the first transfer unit based on a signal from the first substrate detection sensor, and when the positional deviation of the substrate is generated, the control unit controls at least one of the extending/contracting operation, the rotating operation and the lifting operation of the first transfer unit so that the positional deviation is corrected. 
         [0020]    In the present disclosure, the substrate accommodating chamber includes a second substrate loading/unloading port, the substrate processing apparatus including: a container mounting unit configured to mount a plurality of substrates to be processed in the substrate processing unit and a plurality of substrates which have been processed in the substrate processing unit; a second transfer unit configured to perform a rotating operation and/or a sliding operation for selectively accessing the container mounted in the container mounting unit and the substrate accommodating chamber and an extending/contracting operation; a second opening/closing member configured to open and close the second substrate loading/unloading port of the substrate accommodating chamber; a third opening/closing member configured to open and close a substrate loading/unloading port of the container mounted in the container mounting unit; a third substrate detection sensor configured to detect a substrate held by the second transfer unit to be advanced and retreated through the second substrate loading/unloading port; and a fourth substrate detection sensor configured to detect a substrate held by the second transfer unit to be advanced and retreated through the substrate loading/unloading port of the container mounted in the container mounting unit, wherein the control unit controls opening/closing operations of the second and third opening/closing members and an operation of the second transfer unit; in response to a signal received from the third substrate detection sensor as a trigger, which indicates that a substrate extracted from the substrate accommodating chamber by the second transfer unit passes through the second substrate loading/unloading port and arrives at a position where the substrate does not interfere with the second opening/closing member and the second substrate loading/unloading port, the control unit allows the second transfer unit to initiate the rotating operation or the sliding operation for transferring the substrate extracted from the substrate accommodating chamber into the container mounted in the container mounting unit; and in response to a signal received from the fourth substrate detection sensor as a trigger, which indicates that a substrate extracted from the container mounted in the container mounting unit by the second transfer unit passes through the substrate loading/unloading port of the container and arrives at a position where the substrate does not interfere with the third opening/closing member and the substrate loading/unloading port of the container, the control unit allows the second transfer unit to initiate the rotating operation or the sliding operation for transferring the substrate extracted from the container into the substrate accommodating chamber. 
         [0021]    In order to solve the above-described problems, according to another embodiment of the present disclosure, there is provided a substrate transfer method in a substrate processing apparatus, including: accommodating a substrate in a chamber in each of a plurality of substrate processing units and opening and closing a substrate loading/unloading port of the chamber by an opening/closing member; detecting a substrate advanced or retreated through the substrate loading/unloading port by a substrate detection sensor; performing a predetermined process on the substrate in the chamber by each of the plurality of substrate processing units; performing, by a transfer unit, a rotating operation and/or a sliding operation for selectively accessing the plurality of substrate processing units and performing an extending/contracting operation for loading and unloading the substrate into and from the chamber of the accessed substrate processing unit; and controlling, in response to a signal transmitted by the substrate detection sensor as a trigger, which indicates that a substrate extracted from one chamber of the plurality of substrate processing units by the extending/contracting operation of the transfer unit passes through the substrate loading/unloading port of the chamber and arrives at a position where the substrate does not interfere with the opening/closing member and the substrate loading/unloading port, the transfer unit to initiate the rotating operation or the sliding operation for transferring the substrate extracted from the one chamber into another chamber of the plurality of substrate processing units. 
         [0022]    In order to solve the above-described problems, according to another embodiment of the present disclosure, there is provided a substrate transfer method in a substrate processing apparatus, including: accommodating a substrate in a chamber of at least one substrate processing unit and opening and closing a substrate loading/unloading port of the chamber by an opening/closing member; detecting a substrate advanced or retreated through the substrate loading/unloading port by a substrate detection sensor; performing a predetermined process on the substrate in the chamber by each of the plurality of substrate processing units; using a transfer unit including at least two arms respectively configured to hold the substrate and be independently extendable and contractible, performing a rotating operation and/or a lifting operation for loading and unloading a substrate into and from the chamber using the arms; and controlling, in response to a signal received from the substrate detection sensor as a trigger, which indicates that a substrate extracted from the chamber by one of the at least two arms passes through the substrate loading/unloading port of the chamber and arrives at a position where the substrate does not interfere with the opening/closing member and the substrate loading/unloading port, the transfer unit to initiate the rotating operation or the lifting operation for loading a substrate held by the other of the at least two arms into the chamber. 
         [0023]    In order to solve the above-described problems, according to one embodiment of the present disclosure, there is provided a substrate transfer method in a substrate processing apparatus, including: performing a predetermined process on a substrate in a chamber accommodating a substrate by a substrate processing unit; accommodating the substrate in a substrate accommodating chamber to load a substrate to be processed in the substrate processing unit from the outside and to unload a substrate which has been processed in the substrate processing unit to the outside; performing, by a transfer unit, a rotating operation and/or a sliding operation and an extending/contracting operation for selectively accessing the substrate processing unit and the substrate accommodating chamber; opening and closing a substrate loading/unloading port of the substrate accommodating chamber by a substrate accommodating chamber opening/closing member; opening and closing a substrate opening/closing port of the chamber by a chamber opening/closing member; detecting a substrate advanced and retreated through the substrate loading/unloading port of the substrate accommodating chamber by a first substrate detection sensor; and detecting a substrate advanced and retreated through the substrate loading/unloading port of the chamber by a second substrate detection sensor; and controlling, in response to a signal received from the first substrate detection sensor as a trigger, which indicates that a substrate extracted from the substrate accommodating chamber by the extending/contracting operation of the first transfer unit passes through the substrate loading/unloading port of the substrate accommodating chamber and arrives at a position where the substrate does not interfere with the substrate accommodating chamber opening/closing member and the substrate loading/unloading port of the substrate accommodating chamber, the transfer unit to initiate the rotating operation or the sliding operation for transferring the substrate extracted from the substrate accommodating chamber into the chamber; and in response to a signal received from the second substrate detection sensor as a trigger, which indicates that a substrate extracted from the chamber by the extending/contracting operation of the transfer unit passes through the substrate loading/unloading port of the chamber and arrives at a position where the substrate does not interfere with the chamber opening/closing member and the substrate loading/unloading port of the chamber, the transfer unit to initiate the rotating operation or the sliding operation for transferring the substrate extracted from the chamber into the substrate accommodating chamber. 
         [0024]    In order to solve the above-described problems, according to another embodiment of the present disclosure, there is provided a substrate transfer method in a substrate processing apparatus, including: accommodating a substrate in a chamber in a substrate processing unit performing a predetermined process on the substrate; accommodating the substrate in a substrate accommodating chamber to load a substrate to be processed in the substrate processing unit from the outside and to unload a substrate which has been processed in the substrate processing unit to the outside; opening and closing a substrate loading/unloading port of the substrate accommodating chamber by an opening/closing member; using a transfer unit including at least two arms respectively configured to hold the substrate and be independently extendable and contractible, performing a rotating operation and/or a lifting operation for loading and unloading the substrate into and from the chamber and the substrate accommodating chamber by the transfer unit; detecting a substrate advanced and retreated by the transfer unit, through the substrate loading/unloading port of the substrate accommodating chamber by using a substrate detection sensor; and controlling, in response to a signal received from the substrate detection sensor as a trigger, which indicates that a substrate extracted from the substrate accommodating chamber by one of the at least two arms passes through the substrate loading/unloading port of the substrate accommodating chamber and arrives at a position where the substrate does not interfere with the opening/closing member and the substrate loading/unloading port of the substrate accommodating chamber, the transfer unit to initiate the rotating operation or the lifting operation for loading a substrate held by the other of the at least two arms into the substrate accommodating chamber. 
         [0025]    According to the present disclosure, a next operation such as a rotating operation, a sliding operation, a lifting operation and so on, which are required in a drive unit such as a transfer unit or an opening/closing member installed in the substrate processing apparatus, is initiated in response to a substrate detection signal from a substrate detection sensor as a trigger. Accordingly, it is possible to improve a throughput without increasing the operation speed of the drive unit. Further, since the operation speed of the drive unit is not increased, it is possible to avoid a problem of generation of vibration, deterioration of accuracy, an increase in oscillation, and the like. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  is a plan view schematically illustrating the configuration of a plasma processing apparatus according to an embodiment of the present disclosure. 
           [0027]      FIG. 2A  is a view schematically illustrating the configuration of wafer detection sensors provided in the plasma processing apparatus of  FIG. 1  and a processing flow based on detection signals output from the wafer detection sensors. 
           [0028]      FIG. 2B  is a view schematically illustrating a method of detecting a positional deviation of a wafer using the wafer detection sensors provided in the plasma processing apparatus of  FIG. 1 . 
           [0029]      FIG. 3  is a view schematically illustrating an example showing a relationship between the detection of a wafer using the wafer detection sensors and a transfer operation of a scara robot in the plasma processing apparatus of  FIG. 1 . 
           [0030]      FIG. 4  is a plan view schematically illustrating the configuration of another plasma processing apparatus according to a second embodiment of the present disclosure. 
           [0031]      FIG. 5  is a view schematically illustrating a first example showing a relationship between the detection of a wafer W using wafer detection sensors and a transfer operation of a scara robot in the plasma processing apparatus of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION  
       [0032]    Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Here, a plasma processing apparatus for performing a plasma process on a semiconductor wafer (hereinafter, referred to as a “wafer”) is described as a substrate processing apparatus according to the present disclosure. 
         [0033]      FIG. 1  is a plan view schematically illustrating the configuration of a plasma processing apparatus  10  according to a first embodiment of the present disclosure. An operation of the plasma processing apparatus  10  is controlled by a control unit  50 . 
         [0034]    The plasma processing apparatus  10  includes three load ports  16  installed to mount a FOUP that is a carrier (not shown) accommodating a predetermined number of wafers W each of which has a diameter of φ450 mm. A loader module  14  for loading/unloading the wafer W on the FOUP is disposed adjacent to the load ports  16 . A position adjusting mechanism  17  for position-adjusting the wafer W is disposed adjacent to the loader module  14 . Two load lock chambers (load lock modules)  13  are disposed at a side opposite to the load ports  16  with the loader module  14  interposed therebetween. 
         [0035]    The interior of the loader module  14  is always maintained in an atmospheric pressure environment. A wafer transfer unit  18  is disposed in the loader module  14 . The wafer transfer unit  18  transfers the wafer W between the FOUP mounted in the load port  16 , the position adjusting mechanism  17  and the load lock chambers  13 . 
         [0036]    The load lock chamber  13  is configured so that its interior is switchable between a vacuum environment and the atmospheric pressure environment. The interior of the load lock chamber  13  becomes the atmospheric pressure environment when it communicates with the loader module  14  and becomes the vacuum environment when it communicates with the transfer module  11 . The load lock chamber  13  includes a mounting table for mounting the wafer W, and lifting pins for supporting and lifting the wafer W. The lifting pins deliver and receive the wafer W between the wafer transfer unit  18  and a scara robot  15  to be described later, and also deliver and receive the wafer W to and from the mounting table. 
         [0037]    A transfer module  11  having an octagonal shape as viewed from top is disposed at a side opposite to the loader module  14  with the load lock chambers  13  interposed therebetween. Five vacuum processing chambers (processing modules)  12  radially connected to the transfer module  11  are disposed around the transfer module  11 . 
         [0038]    The interior of the transfer module  11  is always maintained at a predetermined vacuum level (decompressed state), and the scara robot  15  for transferring the wafer W is disposed in the transfer module  11 . The scara robot  15  is configured to have an extendable arm for maintaining the wafer W and be rotatable as a whole. In such a configuration, the arm of the scara robot  15  can selectively access the two load lock chambers  13  and the five vacuum processing chambers  12 . The interior of a chamber constituting the vacuum processing chamber  12  is maintained at a predetermined vacuum level. The wafer W is accommodated in the interior of the chamber, thereby performing, on the wafer W, a predetermined plasma process, e.g., an etching process, an ashing process, or the like. 
         [0039]    A gate valve  21  that is an opening/closing member for allowing the interior of the FOUP mounted in the load port  16  to communicate with and be isolated from the loader module  14  is disposed at a side of the load port  16  facing the loader module  14 . Also, wafer detection sensors  31  adjacent to the gate valve  21  to detect whether the wafer W is advanced or retreated through a wafer loading/unloading port of the FOUP (i.e., to detect the presence and position of the wafer W transferred by the wafer transfer unit  18 ) are disposed at a side of the load port  16  facing the loader module  14 . Similarly, wafer detection sensors  32  for detecting whether the wafer W is advanced or retreated through a wafer loading/unloading port of the position adjusting mechanism  17  are disposed at a side of the position adjusting mechanism  17  facing the loader module  14 . 
         [0040]    Also, a gate valve  23  for opening/closing a wafer loading/unloading port at a side of each load lock chamber  13  facing the loader module  14  and wafer detection sensors  33  for detecting whether the wafer W is advanced or retreated through the wafer loading/unloading port of the load lock chamber  13  are disposed at the side of the load lock chamber  13  facing the loader module  14 . In addition, a gate valve  24  for opening/closing a wafer loading/unloading port at a side of the load lock chamber  13  facing the transfer module  11  and wafer detection sensors  34  for detecting whether the wafer W is advanced or retreated through the wafer loading/unloading port at the side of the load lock chamber  13  facing the transfer module  11  are disposed at the side of the load lock chamber  13  facing the transfer module  11 . Further, a gate valve  25  for opening/closing a wafer loading/unloading port of each vacuum processing chamber  12  and wafer detection sensors  35  for detecting whether the wafer W is advanced or retreated through the wafer loading/unloading port of the vacuum processing chamber  12  are disposed at a side of the vacuum processing chamber  12  facing the transfer module  11 . 
         [0041]    The gate valves  21 ,  23 ,  24  and  25  are opened or closed as necessary when the wafer W is transferred. Configurations and functions of the wafer detection sensors  31  to  35  will be described in detail later with reference to  FIGS. 2A and 2B . 
         [0042]    In the plasma processing apparatus  10 , a plasma process is performed on the wafer W in the following order. A transfer control of the wafer W in the plasma processing apparatus  10  or a plasma process control in the vacuum processing chamber  12  is performed by the control unit  50 . A microcomputer (CPU) provided in the control unit  50  controls operations of various drive units constituting the plasma processing apparatus  10  by performing a predetermined program. 
         [0043]    Here, three of the five vacuum processing chambers  12  are configured as etching processing chambers for performing a plasma etching process, and the other two are configured as ashing processing chambers for removing an etching mask formed on the wafer W through ashing. A relationship between the functions of the wafer detection sensors  31  to  35  and the transfer control of the wafer W will be described later with reference to  FIG. 3  and will be omitted in the description of the following processing of the wafer W. 
         [0044]    Although a plurality of wafers W are simultaneously processed in the plasma processing apparatus  10 , the processing of one wafer W will be described here in time series. First, if the FOUP is mounted in the load port  16 , the gate valve  21  installed at the load port  16  holds and opens a lid of the FOUP, so that the wafer transfer unit  18  extracts a wafer W from the FOUP, and loads the held wafer W into the position adjusting mechanism  17 . The wafer W position-adjusted in the position adjusting mechanism  17  is loaded into the load lock chamber  13 , which is maintained in the atmospheric pressure environment by the wafer transfer unit  18 . At this time, the gate valve  24  has been closed. After the gate valve  23  at the side of the load lock chamber  13  facing the loader module  14  is closed, the load lock chamber  13  is decompressed at a predetermined vacuum level. 
         [0045]    If the interior of the load lock chamber  13  reaches the predetermined vacuum level, the gate valve  24  is opened, so that the scara robot  15  unloads the wafer W from the load lock chamber  13  and loads the held wafer W into one etching processing chamber among the vacuum processing chambers  12 . Then, an etching process on the wafer W in the etching processing chamber is performed. The wafer W, on which the process in the etching processing chamber has been terminated, is extracted from the etching processing chamber by the scara robot  15  and loaded into one ashing processing chamber among the vacuum processing chambers  12 . Then, an ashing process on the wafer W in the ashing processing chamber is performed. 
         [0046]    The wafer W, on which the ashing process has been terminated, is extracted from the ashing processing chamber by the scara robot  15  and loaded into the load lock chamber  13 . At this time, the gate valve  23  has been closed. The gate valve  24  is closed, and a purge gas such as nitrogen gas is introduced into the load lock chamber  13  in order to maintain the load lock chamber  13  in the atmospheric pressure environment. At this time, the wafer W mounted on the mounting table installed in the load lock chamber  13  is cooled down to a predetermined temperature through heat exchange with the mounting table. 
         [0047]    If the interior of the load lock chamber  13  becomes an atmospheric pressure environment and the wafer W is cooled down to the predetermined temperature, the gate valve  23  is opened, and the wafer transfer unit  18  extracts the wafer W from the load lock chamber  13  and loads the wafer W at a predetermined position of the FOUP. Accordingly, the processing of the wafer W in the plasma processing apparatus  10  is terminated. 
         [0048]    Next, the configurations and functions of the wafer detection sensors  31  to  35  will be described with reference to  FIGS. 2A and 2B . Subsequently, the relationship between the functions of the wafer detection sensors  31  to  35  and the transfer control of the wafer W in the plasma processing apparatus  10  will be described with reference to  FIG. 3 . Since the wafer detection sensors  31  to  35  have the same configuration and function, the wafer detection sensors  35  installed in the vicinity of the gate valve  25  of the vacuum processing chamber  12  are illustrated in  FIGS. 2A and 2B . 
         [0049]      FIG. 2A  is a view schematically illustrating the configuration of the wafer detection sensors  35  installed in the plasma processing apparatus  10  of  FIG. 1  and a processing flow based on detection signals output from the wafer detection sensors  35 . Additionally,  FIG. 2A  illustrates detection signals respectively output from the wafer detection sensors  31  to  34  and a processing flow based on the detection signals. 
         [0050]    Each of the wafer detection sensors  35  is configured with a pair of a light emitting element  35   a  and a light receiving element  35   b.  The light emitting element  35   a  is, for example, a laser diode, and the light receiving element  35   b  is, for example, a photodiode or the like. Laser light (laser beam) is always emitted toward the light receiving element  35   b  from the light emitting element  35   a.  With this configuration, if a wafer W is present, as indicated by a solid line, between the light emitting element  35   a  and the light receiving element  35   b,  laser light F from the light emitting element  35   a  does not arrive at the light receiving element  35   b.  In this state, an OFF signal is transmitted from the light receiving element  35   b  to the control unit  50 . Meanwhile, if any wafer W is not present, as indicated by a dashed line, between the light emitting element  35   a  and the light receiving element  35   b,  the light receiving element  35   b  receives laser light G from the light emitting element  35   a.  In this state, an ON signal is transmitted from the light receiving element  35   b  to the control unit  50 . The ON/OFF signals may be set opposite to each other. 
         [0051]    Therefore, when the wafer W passes between the light emitting element  35   a  and the light receiving element  35   b,  the ON/OFF signal output from the light receiving element  35   b  is switched. Thus, in response to the ON/OFF signal received from the light receiving element  35   b  as a trigger, the control unit  50  controls an operation of the scara robot  15  (an extending/contracting operation of the arm or a rotating operation of the entire robot) and opening/closing operations of the gate valves  24  and  25 . Similarly, the control unit  50  controls an operation of the scara robot  15  and opening/closing operations of the gate valves  24  and  25 , based on detection signals of the wafer detection sensors  34 , and the control unit  50  controls an operation of the wafer transfer unit  18  and opening/closing operations of the gate valves  21  and  23 , based on detection signals of the wafer detection sensors  31  to  33 . 
         [0052]      FIG. 2B  is a view schematically illustrating a method of detecting a positional deviation of the wafer W using the wafer detection sensors  35  provided in the plasma processing apparatus  10  of  FIG. 1 . In  FIG. 2B , the wafer W is held by the arm (not shown) of the scara robot  15  to move from a position indicated by a dashed line to a position indicated by a solid line. In a case where there is no positional deviation of the wafer W, if the two wafer detection sensors  35  detect the entry (presence) of the wafer W as shown in the left figure of  FIG. 2B , the output signals from the two wafer detection sensors  35  are simultaneously changed from the OFF signals to the ON signals. Thereafter, if the wafer W passes through the two wafer detection sensors  35 , the output signals from the two wafer detection sensors  35  are simultaneously changed from the ON signals to the OFF signals. Due to a change in the output signals, the control unit  50  can determine that any positional deviation of the wafer W has not been generated. 
         [0053]    Meanwhile, in a case where there is a positional deviation of the wafer W as shown in the middle and right figures of  FIG. 2B , one of the two wafer detection sensors  35  detects the entry (presence) of the wafer W, and the other then detects the entry of the wafer W. Hence, the output signal from the one of the two wafer detection sensors  35  is changed from the OFF signal to the ON signal, and the output signal from the other is then changed from the OFF signal to the ON signal. Similarly, when the wafer W passes through the two wafer detection sensors  35 , after the output signal from one of the two wafer detection sensors  35  is changed from the OFF signal to the ON signal, the output signal from the other is changed from the ON signal to the OFF signal. 
         [0054]    The control unit  50  detects of a positional deviation of the wafer W, based on robot encoding values of the scara robot  15  when the OFF and ON signals output from the wafer detection sensors  35  are switched. A positional deviation of a wafer W when the wafer W is loaded into and unloaded from the load lock chamber  13  is detected in this manner. In addition, for the wafer transfer unit  18 , the control unit  50  adjusts the transfer position of the wafer W in the same manner. 
         [0055]      FIG. 3  is a view schematically illustrating an example showing a relationship between the detection of a wafer W using the wafer detection sensors  35  and the transfer operation of the scara robot  15  in the plasma processing apparatus of  FIG. 1 . In  FIG. 3 , only three of the five vacuum processing chambers  12  are shown as vacuum processing chambers  12 A,  12 B and  12 C. Here, the vacuum processing chambers  12 A and  12 B are configured as etching processing units, and the vacuum processing chamber  12 C is configured as an ashing processing unit. In  FIG. 3 , the movement of the wafer W (operation of the scara robot  15 ) transferred from the vacuum processing chamber  12 A to the vacuum processing chamber  12 C is indicated by positions P 1  to P 4  that are center positions of the wafer W and its trace (solid line). The gate valve  25  installed to the vacuum processing chamber  12 A is configured as a gate valve  25 A, and the wafer detection sensors  35  installed thereto are configured as wafer detection sensors  35 α. The gate valve  25  installed to the vacuum processing chamber  12 C is configured as a gate valve  25 C, and the wafer detection sensors  35  installed thereto are configured as wafer detection sensors  35 γ. 
         [0056]    The gate valves  25 A and  25 C of the vacuum processing chambers  12 A and  12 C have been closed. If the control unit  50  receives a signal indicating the termination of an ashing process from the vacuum processing chamber  12 A, the control unit  50  opens the gate valve  25 A of the vacuum processing chamber  12 A, stretches the arm of the scara robot  15  to enter it into the vacuum processing chamber  12 A, and holds the etched wafer W located at a position P 1 . Subsequently, the control unit  50  shrinks the arm of the scara robot  15 , thereby extracting the held wafer W from the vacuum processing chamber  12 A. 
         [0057]    At this time, the wafer detection sensors  35 α detect the movement of the wafer W. As the wafer W passes through the wafer detection sensors  35 α, the output signals from the wafer detection sensors  35 α are changed from the OFF signals to the ON signals and then changed from the ON signals to the OFF signals. In response to the change from the ON signal to the OFF signal as a trigger, which indicates that the wafer W passes through the gate valve  25 A and arrives at a position P 2  (in response to the reception of the OFF signal as a trigger), the control unit  50  initiates a rotating operation about the rotational center O of the scara robot  15 , and simultaneously initiates the closing operation of the gate valve  25 A. At this time, an opening operation of the gate valve  25 C is also initiated, so that it is possible to suppress migration (diffusion) of particles between the transfer module  11  and the vacuum processing chamber  12 A. In addition, the position P 2  of the wafer W is a position at which the wafer W and the arm of the scara robot  15  do not interfere with the gate valve  25 A. 
         [0058]    Here, the contracting operation of the arm of the scara robot  15  is not stopped at a point of time when the wafer W arrives at the position P 2 , and the arm is expanded and contracted during the rotating operation of the scara robot  15  for moving the wafer W from the position P 2  to a position P 3 . The contracting operation of the arm is not suddenly stopped as described above, so that it is possible to allow impact not to be applied to the held wafer W, thereby avoiding, for example, the occurrence of a positional deviation of the wafer W, or the like. In a case where any problem does not occur even when the contracting operation of the arm of the scara robot  15  is stopped and thus the wafer W is transferred to trace a circular arc from the position P 2  to the position P 3 , the extending/contracting operation of the arm during the rotating operation of the scara robot  15  is not necessarily required. 
         [0059]    The gate valve  25 C of the vacuum processing chamber  12 C has been already opened when the wafer W arrives at the position P 3 . Therefore, the control unit  50  allows the arm of the scara robot  15  to stretch and transfer the wafer W from the position P 3  to a position P 4 , delivering and receiving the wafer W into and from the interior of the vacuum processing chamber  12 C. In the sequence of transfer of the wafer W, when a positional deviation of the wafer W is detected by the wafer detection sensors  35 α and  35 γ, the control unit  50  finely adjusts the operation of the scara robot  15  to exactly transfer the wafer W to the position P 4 . Accordingly, the wafer W can be smoothly processed. The control unit  50  may be configured to give an alarm when the transfer of the wafer W cannot be the finely adjusted. 
         [0060]    The above-described transfer control of the wafer W according to the first embodiment is compared with a conventional transfer control. In the conventional transfer control, as indicated by a dashed line in  FIG. 3 , according to a predetermined sequence, after the contracting operation of the arm holding the wafer W located at the position P 1  is terminated and the wafer W arrives at a position P 2   a,  the rotating operation of the scara robot  15  is initiated. Thus, the wafer W arrives at a position P 3   a  and the arm of the scara robot  15  is then stretched, thereby transferring the wafer W to the position P 4 . 
         [0061]    Here, since the angle of the rotating operation of the scara robot  15  is constant, the time required to move the wafer W between the positions P 2  and P 3  through the transfer control of the wafer W according to the first embodiment is equal to the time required to move the wafer W between the positions P 2   a  and P 3   a  though the conventional transfer control. Thus, when the wafer W is transferred from the position P 1  to the position P 4  via the positions P 2  and P 3  by the transfer control of the wafer according to the first embodiment, since the time required to transfer the wafer between the positions P 2  and P 2   a  and between P 3  and P 3   a  is unnecessary, it is possible to reduce the transfer time of the wafer by the unnecessary portion, as compared with when the wafer W is transferred from the position P 1  to the position P 4  via the positions P 2   a  and P 3   a  by the conventional transfer control. 
         [0062]    Further, in the conventional transfer control, since the opening operation of the gate valve  25 C is initiated, for example, at the point of time when the wafer arrives at the position P 3   a,  the arm of the scara robot  15  cannot be stretched even though the wafer W arrives at the position P 3   a.  Therefore, a little waiting time is necessary. However, in the transfer control according to the first embodiment, since the waiting time is unnecessary, the transfer time of the wafer W can be reduced, thereby improving throughput. 
         [0063]    In addition, as compared with the conventional transfer control, in the transfer control of the wafer W according to the first embodiment, since the operation speed of the scara robot  15  is not increased, no problems occur from the generation of vibration, deterioration of transfer accuracy, generation of oscillation, or the like. Further, since the wafer detection sensors  31  to  35  also function as sensors for correcting a transfer center position of the wafer W, which has been conventionally equipped, there is no increase in cost. 
         [0064]    In the above description, the example of transferring (moving) the wafer W between the vacuum processing chambers  12  has been illustrated, but it will be apparent that the transfer control of the wafer W according to the first embodiment may be applied to the transfer of the wafer W between the load lock chamber  13  and the vacuum processing chamber  12 . Similarly, the transfer control of the wafer W according to the first embodiment may be applied to the transfer of the wafer W between the load port  16 , the position adjusting mechanism  17  and the load lock chamber  13  using the wafer transfer unit  18 . In the above-described transfer control of the wafer according to the first embodiment, the operations of the scara robot  15  and the gate valves  25 A and  25 C are controlled in response to sensor signals of the wafer detection sensors  35 α and  35 γ as triggers. However, the present disclosure is not limited thereto, and a preparing operation of a plasma process in the vacuum processing chamber  12  or the like may be performed, for example, in response to sensor signals of the wafer detection sensors  34  as triggers. 
         [0065]    In the above description, the gate valve  25  has been disposed at a side of the wafer loading/unloading port of the vacuum processing chamber  12  facing the transfer module  11 . However, the gate valve  25  may be installed in the vacuum processing chamber  12 . In this case, the wafer detection sensors  35  are also disposed at a side of the wafer loading/unloading port facing the loader module. With this configuration, even when the above-described transfer control of the wafer W according to the first embodiment is performed, the transfer where the wafer W interferes with the wafer loading/unloading port of the vacuum processing chamber  12  is not performed. 
         [0066]    Next, a plasma processing apparatus according to a second embodiment of the present disclosure will be described.  FIG. 4  is a plan view schematically illustrating the configuration of another plasma processing apparatus  10 A according to the second embodiment of the present disclosure. The plasma processing apparatus  10 A has the same loader module  14 , the same load port  16  and the same position adjusting mechanism  17  as those of the plasma processing apparatus  10  according to the first embodiment. But their illustration is omitted in  FIG. 4 . 
         [0067]    The plasma processing apparatus  10 A according to the second embodiment differs from the plasma processing apparatus  10  according to the first embodiment in that a scara robot  40  disposed in the transfer module  11  freely slides in the Y direction shown in  FIG. 4  and also is rotatable in the direction (right turn/left turn) of an arrow R. Also, as another difference, the scara robot  40  includes two multi-joint arms  40   a  and  40   b  for holding wafers W, and two vacuum processing chambers  12  are arranged in the Y direction. In the other points, the plasma processing apparatuses  10  and  10 A are not substantially different from each other. In addition, the arms  40   a  and  40   b  are independently operable. 
         [0068]    A relationship between the detection of the wafer W using the wafer detection sensors  35  and the transfer operation of the scara robot  40  in the plasma processing apparatus  10 A will be described below.  FIG. 5  is a view schematically illustrating a first example showing a relationship between the detection of the wafer W using the wafer detection sensors  35  and the transfer operation of the scara robot  40  in the plasma processing apparatus  10 A of  FIG. 4 . In  FIG. 5 , only two vacuum processing chambers  12 A and  12 B are arranged in the Y direction among six vacuum processing chambers  12 . Here, the vacuum processing chamber  12 A is configured as an etching processing unit, and the vacuum processing chamber  12 B is configured as an ashing processing unit. 
         [0069]    In  FIG. 5 , like  FIG. 3 , the movement of the wafer W (operation of the scara robot  40 ) transferred from the vacuum processing chamber  12 A to the vacuum processing chamber  12 B under the control of the control unit  50  is indicated by a trace (solid line) of positions P 1  to P 4  via P 2  and P 3 , which are center positions of the wafer W. In addition, the movement of the wafer W under the conventional transfer control is indicated by a dashed line (positions P 1  to P 4  via P 2   a  and P 3   a ). The gate valve  25  installed to the vacuum processing chamber  12 A is configured as a gate valve  25 A, and the wafer detection sensors  35  installed thereto are configured as wafer detection sensors  35 α. The gate valve  25  installed to the vacuum processing chamber  12 B is configured as a gate valve  25 B, and the wafer detection sensors  35  installed thereto are configured as wafer detection sensors  35 β. 
         [0070]    In the same manner as described with reference to  FIG. 3 , in the transfer operation of the wafer W shown in  FIG. 5 , the gate valve  25 A of the vacuum processing chamber  12 A is opened, and the arm  40   a  (or  40   b ) of the scara robot  40  extracts the wafer W located at the position P 1  from the vacuum processing chamber  12 A. In response to signals from the wafer detection sensors  35 α as triggers, which indicate that the wafer W passes through the gate valve  25 A and arrives at the position P 2 , the scara robot  40  initiates a Y-direction slide movement toward the vacuum processing chamber  12 B and simultaneously initiates the closing operation of the gate valve  25 A. Also, the opening operation of the gate valve  25 B is initiated. Since the gate valve  25 B of the vacuum processing chamber  12 B has been already opened when the wafer W arrives at the position P 3 , the arm  40   a  of the scara robot  40  transfers the wafer W from the position P 3  to the position P 4 , so that the wafer W is loaded into the vacuum processing chamber  12 B. In a case where it is detected that a positional deviation of the wafer W is generated from signals from the wafer detection sensors  35 β, the scara robot  40  performs an operation correcting the positional deviation. Using such a transfer method of the wafer W, the transfer is possible for a shorter time, as compared with the conventional transfer method. 
         [0071]    In a second example of the relationship between the detection of the wafer W using the wafer detection sensors  35  and the transfer operation of the scara robot  40  in the plasma processing apparatus  10 A, the loading and unloading of the wafer W into and from one vacuum processing chamber  12  are consecutively performed by the two arms  40   a  and  40   b.  The arm  40   b  of the scara robot  40  is set to hold the wafer W before a plasma process is performed. In this state, the gate valve  25  of the vacuum processing chamber  12  is opened, and the arm  40   a  of the scara robot  40  extracts the plasma processed wafer from the vacuum processing chamber  12 A. In response to signals from the wafer detection sensors  35  as triggers, which indicate that the plasma processed wafer passes through the gate valve  25 , the scara robot  40  initiates an R-direction rotating operation, which is required to load the wafer W held by the arm  40   b  into the same vacuum processing chamber  12  as the vacuum processing chamber  12  from which the plasma processed wafer W is extracted. After the rotating operation with a predetermined angle is terminated, the arm  40   b  loads the held wafer W into the vacuum processing chamber  12 . 
         [0072]    By using the transfer method (loading/unloading method) of the wafer W, the transfer of the wafer W is possible for a shorter time, as compared with the conventional transfer method in which the wafer loading operation performed by the arm  40   b  after the wafer unloading operation of the arm  40   a  is completely terminated according to a sequence. Further, the same transfer method can be used for the load lock chamber  13 . 
         [0073]    In the above-described second example of the relationship between the detection of the wafer W using the wafer detection sensors  35  and the transfer operation of the scara robot  40 , when the wafer W is consecutively unloaded from and loaded into one vacuum processing chamber  12  by the two arms  40   a  and  40   b,  the scara robot  40  performs a rotating operation in response to signals of the wafer detection sensors  35  as triggers, which indicate that the wafer W is unloaded from the vacuum processing chamber  12 . On the other hand, the scara robot  40  may be configured so that the arm  40   b  is located below or above the arm  40   a  (at the overlapping position when viewed on the plane of  FIG. 4 ) in a state in which the arm  40   b  holds the wafer W before the plasma process. 
         [0074]    In this case, in response to signals of the wafer detection sensors  35  as trigger signals, which indicate that the wafer W is unloaded from the vacuum processing chamber  12 , the arm  40   b  may be configured to initiate a rising or lowering operation in order to load the wafer W before the plasma process into the vacuum processing chamber  12 . Accordingly, it is possible to transfer the wafer for a shorter time, as compared with the conventional transfer method. Further, the same transfer method can be used for the load lock chamber  13 . 
         [0075]    In the above, the embodiments of the present disclosure have been described, but the present disclosure is not limited thereto. For example, in the above description, the wafer W is detected by the wafer detection sensors  35 , thereby controlling the operation of the scara robot  15  or  40  and the operation of the wafer transfer unit  18 . However, in the scara robot  15  or  40  and the wafer transfer unit  18 , the movement of the arm holding the wafer W may be detected by a sensor. Then, the operation of the scara robot  15  or  40  and the operation of the wafer transfer unit  18  may be controlled based on a signal detected by the sensor. 
         [0076]    Although the plasma processing apparatus is used as a substrate processing apparatus, the present disclosure is not limited thereto and the plasma processing apparatus may be a film forming apparatus, a cleaning apparatus or the like. Although the semiconductor wafer is used as a substrate, the substrate is not limited thereto and may be a glass substrate used in a flat panel display (FPD) such as a liquid crystal display or the like. Thus, the present disclosure is applied to a processing apparatus of a glass substrate for FPD. 
         [0077]    This application claims the right of priority to Japanese Patent Application No. 2012-250325, filed on Nov. 14, 2012, the contents of which is incorporated by reference herein in its entirety.