Abstract:
The robot device according to this invention includes an arm mechanism, multiple hand mechanisms, and a control unit. The arm mechanism has its base end rotatably supported on a base point set in a predetermined position in the horizontal plane, and its free end moves among orthogonal coordinates in the horizontal plane. Each of the multiple hand mechanisms has its support end rotatably supported by the free end, and its holding end moves among polar coordinates in the horizontal plane. The holding ends hold substrates. The control unit drives the arm mechanism so that the free end approaches a base line connecting a base point with the center of a stage without passing over the base point, and drives the multiple hand mechanisms so that an export holding end moves along the base line and a non-export holding end separates from the export holding end.

Description:
CROSS REFERENCE 
       [0001]    This Nonprovisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2008-307732 filed in Japan on Dec. 2, 2008, the entire contents of which are hereby incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to a robot device, installed within a processing chamber such as a vacuum chamber, that transports substrates such as, for example, semiconductor substrates, liquid crystal glass substrates, and magnetic disks between a stage installed outside of the processing chamber and the interior of the processing chamber, and also relates to a control method for such a robot device. 
         [0003]    The manufacture of semiconductor devices, liquid crystal displays, magnetic disks, and so on involves processing the precision substrates used as the materials within a processing chamber. A vacuum chamber is an example of such a processing chamber. The substrates are transported between a stage installed outside of the processing chamber and the interior of the processing chamber by a robot device installed within the processing chamber. 
         [0004]    As described in, for example, JP 2003-188231A, a conventional robot device that transports substrates between a stage and the interior of a processing chamber is provided with an arm mechanism and a hand mechanism. The arm mechanism includes a lower arm, an upper arm, a lower motor, and an upper motor. The hand mechanism includes a hand and a hand motor. 
         [0005]    One end section of each of the lower arm and the upper arm is used as an axial support end, with the two arms supported relative to each other by a shaft. The end section of the lower arm opposite to the shaft support end is a base end axially supported central to a base shaft set within a horizontal surface. Meanwhile, the end section of the upper arm opposite to the shaft support end is a free end that axially supports one end section of the hand serving as an axial support end. The end section of the hand opposite to the shaft support end thereof is a holding end that holds a substrate. 
         [0006]    The lower motor rotates the lower arm central to the base axis. The upper motor, meanwhile, rotates the upper arm central to the shaft. The hand motor rotates the hand central to the free end. When the lower motor and the upper motor are driven individually, the free end moves among orthogonal coordinates within the horizontal surface. Then, when the hand motor is driven, the holding end moves among polar coordinates. When transporting a substrate from within the chamber to a stage, the lower motor, upper motor, and hand motor are driven individually so that the substrate is moved in a straight line following a base line connecting a base point to the center of the stage, thereby minimizing the movement distance. 
         [0007]    The conventional robot device is provided with multiple hand mechanisms for the purpose of streamlining the substrate processing, and is capable of importing and exporting multiple substrates into and out of the processing chamber simultaneously. Meanwhile, even if a substrate is held by each holding end of a robot device provided with multiple hand mechanisms, there are cases where, due to processing issues, only some of the multiple substrates stored within the chamber are to be transported to the stage. It is necessary to move the substrates in a straight line following a base line connecting a base point to the center of the stage in such cases as well. 
         [0008]    However, the conventional robot device and control method thereof have not sufficiently considered interference between the substrates that are not transported and the inner wall of the processing chamber when only some of multiple substrates stored within the chamber are transported to the stage. For this reason, there has been a problem in that the size of the processing chamber cannot be sufficiently reduced. 
         [0009]    For example, when a holding end holding a substrate to be transported is moved with the support end along a straight line that follows a base line, the substrates that are not to be transported will come into contact with the inner wall of the processing chamber if the radius of the processing chamber is shorter than the length from the support end to the outer circumference of the substrate in the lengthwise direction of the hand. For this reason, the radius of the processing chamber cannot be shortened beyond the length from the support end to the outer circumference of the substrate in the lengthwise direction of the hand, and thus the size of the processing chamber cannot be sufficiently reduced. 
         [0010]    It is thus an object of this invention to provide a robot device that moves the free end of an arm axially supporting a support section of a hand among orthogonal coordinates while moving a holding end of the hand among polar coordinates and that, when exporting only some of substrates stored within a processing chamber, can prevent the inner wall of the processing chamber from interfering with the remaining substrates, and that can realize a sufficient reduction in the size of the processing chamber, as well as to provide a control method for such a robot device. 
       SUMMARY OF THE INVENTION 
       [0011]    The robot device according to this invention includes an arm mechanism, multiple hand mechanisms, and a control unit, and exports only some of multiple substrates held by the holding ends of at least two of the multiple hand mechanisms from within a is processing chamber to a stage. The arm mechanism has its base end rotatably supported on a base point set in a predetermined position in the horizontal plane and its free end moves among orthogonal coordinates in the horizontal plane. Each of the multiple hand mechanisms has its support end rotatably supported by the free end, and its holding end moves among polar coordinates in the horizontal plane. The holding ends hold substrates. The control unit drives the arm mechanism so that the free end approaches a base line connecting a base point with the center of a stage without passing over the base point, and drives the multiple hand mechanisms so that an export holding end holding a substrate to be exported moves along the base line and a non-export holding end holding a substrate not to be exported separates from the export holding end. 
         [0012]    At the same time as the free end of the arm mechanism approaches the base line connecting the base point with the center of the stage without passing over the base point, the export holding end on one of the hand mechanisms moves along the base line, and the non-export holding end on the other hand mechanism separates from the export holding end. Because the free end moves among orthogonal coordinates so as to approach the base line without passing over the base point while the export holding end moves among polar coordinates central to the free end, the substrate moves with the export holding end along the base line in the direction of the stage. Because the free end, which is the center of the movement among polar coordinates when the non-export holding end separates from the export holding end, does not pass over the base point, substrates will not come into contact with the inner wall of the processing chamber even in the case where the radius of the processing chamber is shorter than the length from the base end to the outer circumference of the substrate held by the non-export holding end. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a side view of a robot device according to an embodiment of this invention. 
           [0014]      FIG. 2  is a plan view illustrating main elements of a substrate processing device that includes a robot device. 
           [0015]      FIGS. 3A and 3B  are plan views illustrating an outline of a method for exporting a substrate whereby a free end passes through a base point. 
           [0016]      FIGS. 4A and 4B  are plan views illustrating an outline of a first export method for linearly bringing a substrate close to a base line without a free end passing through a base point. 
           [0017]      FIGS. 5A and 5B  are plan views illustrating an outline of an arm pullback amount, a hand length, an extended hand angle, and a retracted hand angle of a robot device when the first export method is used. 
           [0018]      FIGS. 6A to 6D  are timing charts illustrating changes in the various sections of a robot device when the first export method is used. 
           [0019]      FIGS. 7A and 7B  are plan views illustrating an outline of a second export method for bringing a substrate close to a base line in a circular arc without a free end passing through a base point. 
           [0020]      FIG. 8  is a plan view illustrating an outline of a hand length, an extended hand angle, and a retracted hand angle of a robot device when the second export method is used. 
           [0021]      FIGS. 9A to 9D  are timing charts illustrating changes in the various sections of a robot device when the second export method is used. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    As shown in  FIG. 1 , a robot device  1  is provided with an arm mechanism  10 , hand mechanisms  20 A and  20 B, and a control unit  30 . 
         [0023]    The arm mechanism  10  is provided with a lower arm  11 , an upper arm  12 , a lower motor  13 , and an upper motor  14 . The lower arm  11  and the upper arm  12  are supported relative to each other by a shaft  111  located on one end of each arm. The end section of the lower arm  11  opposite to the shaft end  111  is supported by a support pillar  15  so as to be rotatable on a base shaft  16 . A shaft  122  is provided on the free end of the upper arm  12 , which is the side opposite to the shaft end  111 . 
         [0024]    The lower motor  13  is contained within the support pillar  15 , and rotates the lower arm  11  around the base shaft  16  in the horizontal plane via a transmission mechanism (not shown). The upper motor  14  is also contained within the support pillar  15 , and rotates the upper arm  12  around the shaft  111  via a transmission mechanism (not shown). Driving the upper motor  13  and the lower motor  14  individually makes it possible to move the shaft  122  among orthogonal coordinates within the horizontal plane. 
         [0025]    The arm mechanism  10  may be provided with an intermediate arm disposed between the lower arm  11  and the upper arm  12  and an intermediate motor that rotates the intermediate arm. 
         [0026]    The hand mechanism  20 A is provided with a hand  21 A and a hand motor  22 A. A support end  211 A of the hand  21 A is axially supported by a shaft  122 , and a holding end  212 A holds a substrate  4 A. The hand motor  22 A is contained within the support pillar  15 , and rotates the hand  21 A around the shaft  122  in the horizontal plane via a transmission mechanism (not shown). 
         [0027]    The hand mechanism  20 B is provided with a hand  21 B and a hand motor  22 B. A support end  211 B of the hand  21 B is axially supported by the shaft  122 , and a holding end  212 B holds a substrate  4 B. The hand motor  22 B is contained within the support pillar  15 , and rotates the hand  21 B around the shaft  122  in the horizontal plane via a transmission mechanism (not shown). 
         [0028]    Driving the hand motors  22 A and  22 B individually moves the hands  21 A and  21 B independent of each other among polar coordinates in the horizontal plane. 
         [0029]    The hand mechanisms  20 A and  20 B may each be provided with multiple hands in the vertical direction. 
         [0030]    The control unit  30  generates driving data for the lower motor  13 , the upper motor  14 , and the hand motors  22 A and  22 B, and outputs that data to a motor driver (not shown). The motor driver drives the lower motor  13 , the upper motor  14 , and the hand motors  22 A and  22 B in accordance with the driving data. 
         [0031]    As shown in  FIG. 2 , the robot device  1  is installed within a processing chamber  2 , and transports substrates  4  between a stage  3  outside of the processing chamber  2  and the interior of the processing chamber via a gate  2   a  in the processing chamber  2 . 
         [0032]    The robot device  1  is disposed so that the base shaft  16  is located in the center of the processing chamber  2 . Due to the structure of the gate  2 A, and in order to minimize the transport distance, the robot device  1  transports substrates  4  along a base line  17  that connects the base shaft  16  with the center of the stage  3 . 
         [0033]    When exporting substrates so that the shaft  122  passes over the base shaft  16 , the hand  21 A that holds a substrate  4 A to be exported and the hand  21 B that holds a substrate  4 B not to be exported first overlap on the base line  17 , as shown in  FIG. 3A . From the state, the lower motor  13  and the upper motor  14  are driven, thereby moving the lower arm  11  and the upper arm  12  so that the shaft  122  moves along the base line  17  from a point upon an extension of the base line  17 , passing over the base shaft  16 , as shown in  FIG. 3B . Meanwhile, the hand motor  22 B is driven, thereby moving the hand  21 B so that the holding end  212 B, which is a holding end not used for exporting, separates from the holding end  212 A, which is a holding end used for exporting. 
         [0034]    If the hand  21 B is moved so that the holding end  212 B separates from the holding end  212 A while moving the lower arm  11  and upper arm  12  so that the shaft  122  passes over the base shaft  16 , the inner diameter of the processing chamber  2  cannot be sufficiently reduced in size. 
         [0035]    In other words, in order to prevent the substrate  4 B from making contact with the inner wall of the processing chamber  2  when moving the holding end  212 B among polar coordinates around the shaft  122  so as to separate from the holding end  212 A, it is necessary for the inner wall of the processing chamber  2  to be located beyond of the end of the outer circumference of the substrate  4 B when the shaft  122  is over the base shaft  16 . Therefore, the radius β of the processing chamber  2  cannot be reduced beyond the length α in the lengthwise direction of the hand  21 B from the shaft  122  to the end of the outer circumference of the substrate  4 B. 
         [0036]    Accordingly, as shown in  FIGS. 4A and 4B , the control unit  30  first positions the holding end  212 A above the base line  17  in a position in which the shaft  122  is distanced from a line extending from the base line  17 . From the state, the control unit  30  drives the lower motor  13  and the upper motor  14 , thereby moving the lower arm  11  and the upper arm  12  so that the free end  122  linearly approaches the base line  17 . Meanwhile, the control unit  30  drives the hand motor  22 A, thereby moving the hand  21 A so that the holding end  212 A moves toward the stage  3  along the base line  17 . The control unit  30  also drives the hand motor  22 B, thereby rotating the hand  21 B so that the holding end  212 B separates from the holding end  212 A. 
         [0037]    In this manner, the hand  21 B is rotated over the base line  17  by causing the holding end  212 B to separate from the holding end  212 A that moves along the base line  17  while linearly bringing the shaft  122  closer to the base line  17  without the shaft  122  passing over the base point  16 . Therefore, the substrate  4 B will not make contact with the inner wall of the processing chamber  2  even if the radius β of the processing chamber  2  is smaller than the length α in the lengthwise direction of the hand  21 B from the support end  211 B to the end of the outer circumference of the substrate  4 B, and thus the inner diameter of the processing chamber to can be reduced. 
         [0038]    In  FIGS. 5A and 5B , the following equation holds true when the arms  11  and  12  are moved, thereby moving the shaft  122  a distance X so that the holding end  212 A is positioned over the base line  17 : 
         [0000]    
       
         
           
             X 
             = 
             
               
                 XB 
                 - 
                 XA 
               
                
               
                 
 
               
                
               
                   
               
               = 
               
                 
                   
                     Y 
                     / 
                     tan 
                   
                    
                   
                       
                   
                    
                   θ 
                    
                   
                       
                   
                    
                   W 
                 
                 - 
                 XA 
               
             
           
         
       
     
         [0039]    As shown in  FIG. 5B , a first export method causes the hand  21 A to revolve along a polar coordinate trajectory while causing the shaft  122  to move along rectangular coordinates. The hand angle Δθ at this time is found by taking the arm movement amount as ΔX, the length of the hand  21 A as L, and the final hand angle as θW, as follows: 
         [0000]      Δθ=θ1−θ2 
         [0000]      θ2=180−90−θ W= 90−θ W    
         [0000]      ƒ1=cos −1 ( B/L ) 
         [0000]        B=A ·sin θ W    
         [0000]    
       
      
       A=L−ΔX  
      
     
         [0000]    Based on this relationship, the hand angle Δθ is found through the following equation using the arm movement amount ΔX: 
         [0000]      Δθ=cos −1 {( L−ΔX )·sin θ θW/L }−(90−θ W ) 
         [0040]    In the case where the hand length L of the hand  21 A is 210 mm and the final hand angle θW is 30 deg, and assuming a maximum speed V of 120 deg/sec and an acceleration a of 400 deg/sec 2 , the arm movement distance and angle of the extended hand  21 A change as shown in  FIG. 6A , and the extension distance of the substrate  4 A changes as shown in  FIG. 6B . In addition, the arm movement distance displacement and the angular displacement of the extended hand  21 A change as shown in  FIG. 6C , and the extension distance displacement of the substrate  4 A changes as shown in  FIG. 6D . 
         [0041]    As shown in  FIGS. 7A and 7B , a second export method causes the holding end  212 B to separate from the holding end  212 A that moves along the base line  17  while bringing the shaft  122  closer to the base line  17  in a circular arc without the shaft  122  passing over the base point  16 . According to this method as well, the substrate  4 B will not make contact with the inner wall of the processing chamber  2  even if the radius β of the processing chamber  2  is smaller than the length α in the lengthwise direction of the hand  21 B from the support end  122 B to the end of the outer circumference of the substrate  4 B, and thus the inner diameter of the processing chamber to can be reduced. 
         [0042]    The distance LC denoted in  FIG. 8  is found through the following equation, assuming that the arm pullback amount of the arms  11  and  12  are LA and the arm angle is θA: 
         [0000]        LC=LA ×sin θ A    
         [0000]    The hand angle θB is found through the following equation, assuming that the hand length of the hand  21 A is LB: 
         [0000]    
       
         
           
             
               θ 
                
               
                   
               
                
               B 
             
             = 
             
               
                 
                   sin 
                   
                     - 
                     1 
                   
                 
                  
                 
                   ( 
                   
                     LC 
                     / 
                     LB 
                   
                   ) 
                 
               
                
               
                 
 
               
                
               
                   
               
               = 
               
                 
                   sin 
                   
                     - 
                     1 
                   
                 
                  
                 
                   { 
                   
                     
                       ( 
                       
                         LA 
                         × 
                         sin 
                          
                         
                             
                         
                          
                         θ 
                          
                         
                             
                         
                          
                         A 
                       
                       ) 
                     
                     / 
                     LB 
                   
                   } 
                 
               
             
           
         
       
     
         [0043]    In the case where the arm pullback amount LA is 185 mm and the hand length LB of the hand  21 A is 210 mm, and assuming a maximum speed V of 120 deg/sec and an acceleration a of 400 deg/sec 2 , the angle θA between the arm and the extended hand  21 A and the angle θB between the arm and the retracted hand  21 B change as shown in  FIG. 9A , and the extension distance of the substrate  4 A changes as shown in  FIG. 9B . In addition, the angular displacement between the arm and the extended hand  21 A and the angular displacement between the arm and the retracted hand  21 B change as shown in  FIG. 9C , and the extension distance displacement of the substrate  4 A changes as shown in  FIG. 9D . 
         [0044]    Although the robot device  1  is provided with two hand mechanisms  20 , note that the invention is not limited thereto. Even in the case where the robot device  1  is provided with three or more hand mechanisms  20 , this invention can be applied when at least two of the hand mechanisms  20  hold substrates  4  and only some of those substrates are exported from the processing chamber  2  to the stage  3 . 
         [0045]    It should be understood that the descriptions in the above embodiment are in all ways exemplary and are in no way limiting. The scope of the invention is defined not by the above embodiment but by the scope of the appended claims. Furthermore, the scope of the invention is intended to include all modifications within the scope and meaning equivalent to the scope of the appended claims.