Patent Publication Number: US-2021175097-A1

Title: Carrier positioning member and carrier placement platform

Description:
TECHNICAL FIELD 
     The present application relates to a carrier positioning member for positioning a carrier that stores a plate-shaped load on a base, and a carrier placement platform for placing the carrier. 
     BACKGROUND ART 
     When semiconductor elements are formed on a semiconductor wafer (semiconductor substrate), several 100 process steps are taken. In transporting and storing a semiconductor wafer between processes in the middle of forming semiconductor elements, a carrier for storing the semiconductor wafer in each of a plurality of grooves formed inside is often used. Many processing apparatuses for forming semiconductor elements on a semiconductor wafer are single-wafer processing apparatuses for processing semiconductor wafers one by one. In a single-wafer processing apparatus, a carrier is placed on a loader including a base such that semiconductor wafers are kept horizontal, the semiconductor wafers to be processed are taken out one by one from a groove of the carrier by a robot arm or the like, and processed semiconductor wafers are stored in the carrier. 
     For example, Patent Document 1 discloses a placement apparatus that corresponds to a placement platform having a base on which a cassette (carrier) for stacking and storing semiconductor wafers in multiple stages is positioned and placed. When a semiconductor wafer is taken in and out from the cassette, it is necessary to place the cassette at a fixed position (set position). Therefore, support members for positioning the cassette are provided in the placement apparatus of a substrate loading/unloading unit corresponding to a loader. The cassette is placed at the set position of the placement platform such that the horizontal positions of front-side corner parts, rear-side foot parts, and side faces of the cassette are restricted by six guide members (positioning members) in the support members installed on the base. 
     Other methods of placing the carrier in the set position of the base of the placement platform include a method of placing the carrier in the set position of the base of the placement platform by a positioning block (guide member) that is provided on the lower side of the carrier and in which a groove for fitting a bar or the like is formed (refer to Patent Document 2), a method of placing the carrier in the set position of the base of the placement platform by engaging a pin or the like (guide member) formed on the base of the placement platform with a kinematic coupling provided on the lower side of the carrier (refer to Patent Document 3.), and the like. In any method of placing the carrier on the set position of the base of the placement platform, the carrier is fitted to the guide member from the upper side when the carrier is placed on the base of the placement platform, and the carrier is moved upward to be pulled out from the guide member when the carrier is moved from the base of the placement platform. 
     CITATION LIST 
     Patent Document 
     Patent Document 1: Japanese Patent Application Laid-open No. H09-148423 (FIGS. 1 and 2) 
     Patent Document 2: Japanese Patent Application Laid-open No. 2002-93877 (FIG. 3) 
     Patent Document 3: Japanese Patent Application Laid-open No. 2000-223553 (FIG. 3) 
     SUMMARY OF INVENTION 
     Problems to be Solved by Invention 
     On a side for taking in and out a semiconductor wafer being an example of a plate-shaped load, the carrier has a structure in which the semiconductor wafer can be taken out as it is. Therefore, in the placement platform on which the carrier is placed with the semiconductor wafer kept horizontal, when the carrier is placed on the base or when the carrier is moved from the base, a problem arises in that the carrier is tilted by mistake to the side where the semiconductor wafer is taken in and out and the semiconductor wafer slips off from the carrier. 
     An object of the technology disclosed in the specification of the present application is to obtain a carrier positioning member that prevents a plate-shaped load such as a semiconductor wafer from slipping off from the carrier when the carrier is placed on a base or when the carrier is moved from the base. 
     Means for Solving Problems 
     An example of a carrier positioning member disclosed in the specification of the present application is a carrier positioning member that is fixed to a base and that positions, on the base, a carrier storing a plurality of plate-shaped loads such that front faces or rear faces thereof face the base. A side in an opening of the carrier in which the plate-shaped loads are taken in and out is a front side, and a side opposite to the opening of the carrier is a rear side. The carrier positioning member comprises two front-side stoppers that come into contact with two opening edge parts being end parts of the opening of the carrier to restrict movement of the carrier to the front side, and two rear-side stoppers that come into contact with two plate-shaped end parts formed on the rear side of the carrier to restrict movement of the carrier to the rear side and movement in a direction vertical to the base. 
     Effect of Invention 
     In an example of the carrier positioning member disclosed in the specification of the present application, since the two front-side stoppers restrict movement of the carrier to the front side and the two rear-side stoppers restrict movement of the carrier to the rear side and movement of the carrier in the direction vertical to the base when the carrier is placed on the base on which the carrier positioning member is fixed or when the carrier is moved from the base on which the carrier positioning member is fixed, the plate-shaped loads can be prevented from slipping off from the carrier. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram showing a positioning member and a carrier placement platform according to Embodiment 1. 
         FIG. 2  is a plan view of a rear-side stopper of  FIG. 1 . 
         FIG. 3  is a diagram showing the carrier placement platform of  FIG. 1  and a carrier. 
         FIG. 4  is a diagram for explaining a method of moving the carrier from the carrier placement platform of  FIG. 1 . 
         FIG. 5  is a diagram for explaining a method of moving the carrier from the carrier placement platform of  FIG. 1 . 
         FIG. 6  is a diagram showing a positioning member and a carrier placement platform according to Embodiment 2. 
         FIG. 7  is a plan view of a rear-side stopper of  FIG. 6 . 
         FIG. 8  is a diagram for explaining problems of the positioning member and the carrier placement platform according to Embodiment 2. 
         FIG. 9  is a diagram showing a positioning member and a carrier placement platform according to Embodiment 3. 
         FIG. 10  is a plan view of a rear-side stopper part of  FIG. 9 . 
         FIG. 11  is a diagram for explaining a method of placing a carrier on the carrier placement platform of  FIG. 9 . 
         FIG. 12  is a diagram for explaining a method of placing the carrier on the carrier placement platform of  FIG. 9 . 
         FIG. 13  is a diagram for explaining a method of placing the carrier on the carrier placement platform of  FIG. 9 . 
         FIG. 14  is a diagram showing a positioning member and a carrier placement platform according to Embodiment 4. 
         FIG. 15  is a plan view showing a main part of a rear-side stopper of  FIG. 14 . 
     
    
    
     MODES FOR CARRYING OUT INVENTION 
     Embodiment 1 
       FIG. 1  is a diagram showing a positioning member and a carrier placement platform according to Embodiment 1.  FIG. 2  is a plan view of a rear-side stopper of  FIG. 1 , and  FIG. 3  is a diagram showing the carrier placement platform of  FIG. 1  and a carrier.  FIGS. 4 and 5  each are a diagram for explaining a method of moving the carrier from the carrier placement platform of  FIG. 1 . The carrier placement platform  50  includes a base  3  and the positioning member  30 . The positioning member  30  includes two rear-side stoppers  1  and two front-side stoppers  2 . The rear-side stoppers  1  restrict foot parts  6  so that the carrier  4  cannot move to a rear side (positive side in x-direction), the foot parts  6  being positioned at ends on an opposite side (hereinafter referred to as rear side) to a side of an opening  45  (hereinafter referred to as front side) where a wafer  5  is taken in and out, namely, on the opposite side where the wafer  5  is taken in and out in the carrier  4 , and also restrict the foot parts  6  of the carrier  4  not to move to an upper side (positive side in z-direction) of the base  3 ; that is, they restrict the foot parts  6  not to be separated from the base  3 . The front-side stoppers  2  restrict the carrier  4  not to move to the front side (negative side in x-direction). The base  3  is, for example, a base of a loader in a processing apparatus for forming semiconductor elements on a semiconductor wafer and the positioning member  30  is fixed thereto with a fixing screw  26 . In  FIG. 1 , the direction from the front-side stoppers  2  to the rear-side stoppers  1  is the x-direction, the direction vertical to a placing face of the rear-side stoppers  1  and the front-side stoppers  2  on the base  3  is the z-direction, and the direction perpendicular to the x-direction and the z-direction is the y-direction. 
     As shown in  FIG. 3 , the carrier  4  includes a body  43  for holding the wafer  5 , a side plate  41  on a side in contact with the base  3 , a side plate  42  on a side opposite to the side plate  41 , opening edge parts  7  connected to the body  43 , and an opening  45  for taking in and out the wafer  5 . The opening edge part  7  has an opening-edge-part front face  7   a  facing an opposed face to the carrier in the front-side stopper  2 , and an opening-edge-part side face  7   b  that is a side face opposite to an inner side of the body  43  in which grooves for storing the wafer  5  are formed and that is connected to the opening-edge-part front face  7   a.  The opening edge part  7  is also an end of the opening  45  in the y-direction. In the side plates  41  and  42 , the foot part  6  being the plate-shaped end part is formed on a side opposite to the side of the opening  45  (side of opening-edge-part front face  7   a ). When the wafer  5  is stored, the carrier  4  is typically placed with the foot part  6  being kept downward and the side of the opening  45  of the carrier  4  being kept upward. The side of the opening  45  is appropriately referred to as an opening side. The rear-side stopper  1  includes a principal part  22  formed with a hole  33 , and a claw part  25 . The rear-side stopper  1  includes the principal part  22  that restricts movement of the foot part  6  being the plate-shaped end part in the carrier  4  to the rear side, and the claw part  25  that restricts the movement of the foot part  6  being the plate-shaped end part in the direction vertical to the base  3 . The rear-side stopper  1  is fixed to the base  3  with the fixing screw  26  inserted into the hole  33 . The hole  33  is also formed in the front-side stopper  2 , and the front-side stopper  2  is fixed to the base  3  with the fixing screw  26  inserted into the hole  33 . A plurality of the wafers  5  is stored in the carrier  4  such that the front faces or the rear faces thereof face the base  3 .  FIG. 3  shows an example in which five wafers  5  are stored in the carrier  4 . 
       FIG. 3  shows a diagram in which the carrier  4  is placed on the carrier placement platform  50 . In Embodiment 1, an example is shown in which the front-side stopper  2  is cubic, and the principal part  22  of the rear-side stopper  1  is cubic. An inner side face of the front-side stopper  2 , which is a side face on the side of the rear-side stopper  1 , is an opposed face to the carrier that faces the opening-edge-part front face  7   a  of the carrier  4 . An inner side face of the rear-side stopper  1 , which is a side face of the principal part  22  on the side of the front-side stopper  2 , is an opposed face to the carrier that faces a bottom face of the foot part  6  of the carrier  4 . The opposed face to the carrier in the rear-side stopper  1  is in contact with the bottom face of the foot part  6  of the carrier  4 . An inner side face of the foot part  6  (foot part inner side face) in the side plate  41  of the carrier  4  that faces the side plate  42  is in contact with an inner side face (claw part inner side face) of the claw part  25  facing the base  3  in the rear-side stopper  1 . The opposed face to the carrier in the front stopper  2  is in contact with the opening-edge-part front face  7   a  of the carrier  4 . The two front-side stoppers  2  come into contact with the two opening edge parts  7  that are the ends of the opening  45  of the carrier  4 , and restrict movement of the carrier  4  to the front side. The two rear-side stoppers  1  come into contact with the foot parts  6  that are the two plate-shaped end parts formed on the rear side of the carrier  4 , and restrict the movement of the carrier  4  to the rear side and the movement in the direction vertical to the base  3 . In the carrier  4 , the opening-edge-part front faces  7   a  are in contact with the opposed faces to the carrier in the front stoppers  2 , and the foot parts  6  are in contact with the opposed faces to the carrier in the principal parts  22  of the rear-side stoppers  1  and are in contact with the claw part inner side faces of the claw parts  25 , so that the position in the horizontal direction is restricted; that is, the carrier  4  is positioned at a set position of the carrier placement platform  50 . 
     As shown in  FIG. 3 , in the carrier  4  placed on the carrier placement platform  50 , the movement of the foot parts  6  to the upper side is restricted by the rear-side stoppers  1 . Therefore, the foot parts  6  of the carrier  4  cannot be moved in the direction directly upward, that is, in the direction vertical to the placing face of the rear-side stoppers  1  and the front-side stoppers  2  on the base  3  (positive side in z-direction). Further, the carrier  4  cannot be placed on the carrier placement platform  50  from the direction directly above the base  3  of the carrier placement platform  50  owing to the claw parts  25  of the rear-side stoppers  1 . Since the positioning member  30  and the carrier placement platform  50  are provided with the rear-side stoppers  1  having the claw parts  25 , the positioning member  30  and the carrier placement platform  50  have structures in which the carrier  4  cannot be placed from the directly upward direction, and the carrier  4  cannot be moved in the directly upward direction. 
     Referring to  FIGS. 4 and 5 , a method of moving the carrier  4  from the carrier placement platform  50  will be described. In  FIGS. 4 and 5 , the base  3  is omitted. When the carrier  4  placed on the carrier placement platform  50  is moved from the base  3  of the carrier placement platform  50  as shown in  FIG. 3 , if the carrier  4  is tilted as indicated by an arrow  8  as shown in  FIG. 4 , the opening edge parts  7  being front side of the carrier  4  are lifted up as indicated by an arrow  9 . Then, the opening edge parts  7  are tilted until they become higher than the front-side stoppers  2 . Further, as shown in  FIG. 5 , while the carrier  4  is kept tilted to the rear side, the opening edge parts  7  are kept in a state where the movement thereof is not restricted by the front-side stoppers  2 , and the carrier  4  is moved forward and obliquely upward as indicated by an arrow  10 . Then, the foot parts  6  move to the front side as indicated by an arrow  11 , and exit from the rear-side stoppers  1 . When the carrier  4  is moved from the base  3  of the carrier placement platform  50 , since the opening edge parts  7  of the carrier  4  pass upper sides of the front-side stoppers  2  with contacting the front-side stoppers  2  or without contacting the front-side stoppers  2 , the carrier  4  is not tilted to the front side. 
     When the foot parts  6  exit from the rear-side stoppers  1 , the movement of the foot parts  6  is not restricted by the rear-side stoppers  1 , so that the carrier  4  can be moved upward from the base  3  of the carrier placement platform  50 . Since the carrier  4  is tilted to the rear side when the carrier  4  is moved from the carrier placement platform  50 , the carrier is not tilted to the front side by mistake. When the carrier  4  is placed on the carrier placement platform  50 , the reverse procedure is performed. Even in this case, since the carrier  4  is tilted to the rear side, the carrier  4  is not tilted to the front side by mistake. It should be noted that the placing of the carrier  4  on the carrier placement platform  50  and the movement of the carrier  4  from the carrier placement platform  50  are performed by a robot arm or an operator of a processing apparatus. 
     The positioning member  30  of Embodiment 1 includes the rear-side stoppers  1  and the front-side stoppers  2  that are designed such that the carrier  4  is always tilted to the rear side when the carrier  4  is placed on the base  3  or when the carrier  4  is moved from the base  3 . Therefore, the carrier  4  is not tilted to the front side by mistake, and plate-shaped loads (wafers  5 ) can be prevented from slipping off from the carrier  4 . The carrier placement platform  50  of Embodiment 1 includes the rear-side stoppers  1  and the front-side stoppers  2  that are designed such that the carrier  4  is always tilted to the rear side when the carrier  4  is placed on the base  3  or when the carrier  4  is moved from the base  3 . Therefore, the carrier  4  is not tilted to the front side by mistake, and the plate-shaped loads (wafers  5 ) can be prevented from slipping off from the carrier  4 . 
     As described above, the positioning member  30  of Embodiment 1 is a carrier positioning member that is fixed to the base  3  and that positions, on the base  3 , the carrier  4  storing a plurality of the plate-shaped loads (wafers  5 ) such that the front faces or the rear faces thereof face the base  3 . A side in the opening  45  of the carrier  4  in which the plate-shaped loads (wafers  5 ) is taken in and out is the front side, and a side opposite to the opening  45  of the carrier  4  is the rear side. The positioning member  30  of Embodiment 1 is provided with the two front-side stoppers  2  that come into contact with the two opening edge parts  7  being the ends of the opening  45  of the carrier  4  to restrict the movement of the carrier  4  to the front side, and the two rear-side stoppers  1  that come into contact with the two plate-shaped end parts (foot parts  6 ) formed at the rear side of the carrier  4  to restrict the movement of the carrier  4  to the rear side and the movement in the direction vertical to the base  3 . With the configuration of the positioning member  30  of Embodiment 1, since the two front-side stoppers  2  restrict the movement of the carrier  4  to the front side and the two rear-side stoppers  1  restrict the movement of the carrier  4  to the rear side and the movement in the direction vertical to the base  3 , when the carrier  4  is placed on the base  3  on which the positioning member  30  for the carrier is fixed or when the carrier  4  is moved from the base  3  on which the positioning member  30  for the carrier is fixed, the plate-shaped loads (wafers  5 ) can be prevented from slipping off from the carrier  4 . 
     As described above, the carrier placement platform  50  of Embodiment 1 includes the base  3  and the positioning member  30  fixed to the base  3 . The positioning member  30  is the carrier positioning member that is fixed to the base  3  and that positions, on the base  3 , the carrier  4  storing a plurality of the plate-shaped loads (wafers  5 ) such that the front faces or the rear faces thereof face the base  3 . The side in the opening  45  of the carrier  4  in which the plate-shaped loads (wafers  5 ) is taken in and out is the front side, and the side opposite to the opening  45  of the carrier  4  is the rear side. The positioning member  30  is provided with the two front-side stoppers  2  that come into contact with the two opening edge parts  7  being the ends of the opening  45  of the carrier  4  to restrict the movement of the carrier  4  to the front side, and the two rear-side stoppers  1  that come into contact with the two plate-shaped end parts (foot parts  6 ) formed at the rear side of the carrier  4  to restrict the movement of the carrier  4  to the rear side and the movement in the direction vertical to the base  3 . With the configuration of the carrier placement platform  50  of Embodiment 1, since the two front-side stoppers  2  restrict the movement of the carrier  4  to the front side and the two rear-side stoppers  1  restrict the movement of the carrier  4  to the rear side and the movement in the direction vertical to the base  3 , when the carrier  4  is placed on the base  3  of the carrier placement platform  50  or when the carrier  4  is moved from the base  3  of the carrier placement platform  50 , the plate-shaped loads (wafers  5 ) can be prevented from slipping off from the carrier  4 . 
     Embodiment 2 
       FIG. 6  is a diagram showing a positioning member and a carrier placement platform according to Embodiment 2.  FIG. 7  is a plan view of a rear-side stopper of  FIG. 6 .  FIG. 8  is a diagram for explaining problems of the positioning member and the carrier placement platform according to Embodiment 2. In the drawings, components common to those of Embodiment 2 are denoted by the same reference numerals and signs as those of Embodiment 1. The positioning member  30  and the carrier placement platform  50  of Embodiment 2 are different from the positioning member  30  and the carrier placement platform  50  of Embodiment 1 in that rear-side stoppers  12  and front-side stoppers  13  having a lateral displacement prevention function are placed on the base  3  in place of the rear-side stoppers  1  and the front-side stoppers  2 . In  FIG. 8 , the base  3  is omitted. 
     Referring to  FIG. 8 , the problems of the positioning member  30  and the carrier placement platform  50  of Embodiment 2 will be described. In the carrier placement platform  50  on which the positioning member  30  of Embodiment 1 is fixed, there is a short period of time during which the carrier  4  can move in a lateral direction (y-direction). That is, when the carrier  4  is moved from the base  3  of the carrier placement platform  50 , the opening edge parts  7  of the carrier  4  may come off from the front-side stoppers  2  as shown in  FIG. 8  if the carrier  4  is displaced in the lateral direction by mistake. Specifically, when the carrier  4  is tilted such that the opening edge parts  7  of the carrier  4  are higher than the front-side stoppers  2 , movement of the opening edge parts  7  of the carrier  4  cannot be restricted by the front-side stoppers  2 , and when the carrier  4  is displaced in the lateral direction by mistake, the foot parts  6  of the carrier  4  may come off from the rear-side stoppers  1 . When the foot parts  6  of the carrier  4  come off from the rear-side stoppers  1 , the carrier  4  is tilted to a front side by mistake, and the wafer  5  may slip off. 
     In the positioning member  30  of Embodiment 2, since the rear-side stoppers  12  and the front-side stoppers  13  have the function of preventing the lateral displacement, lateral movement of the carrier  4  can be restricted when the carrier  4  is moved from the base  3 , and the fall of the wafer  5  caused by the lateral displacement can be prevented. In the carrier placement platform  50  of Embodiment 2, since the rear-side stoppers  12  and the front-side stoppers  13  have the function of preventing the lateral displacement, the lateral movement can be restricted when the carrier  4  is moved from the base  3 , and the fall of the wafer  5  caused by the lateral displacement can be prevented. Referring to  FIGS. 6 and 7 , the positioning member  30  and the carrier placement platform  50  of Embodiment 2 will be described in detail. 
     The positioning member  30  includes two rear-side stoppers  12  and two front-side stoppers  13 . In  FIG. 6 , the direction from the front-side stoppers  13  to the rear-side stoppers  12  is the x-direction, the direction vertical to the placing face of the rear-side stoppers  12  and the front-side stoppers  13  on the base  3  is the z-direction, and the direction perpendicular to the x-direction and the z-direction is the y-direction.  FIG. 7  shows the rear-side stopper  12  on the positive side in the y-direction. The rear-side stopper  12  on the negative side in the y-direction has a shape such that the rear-side stopper  12  on the positive side in the y-direction is inverted in shape with respect to a broken line  38  of the x-direction. The front-side stopper  13  on the negative side in the y-direction and the front-side stopper  13  on the positive side in the y-direction are inverted in shape to each other with respect to the broken line  38  of the x-direction. 
     The rear-side stopper  12  includes a principal part  22  formed with the hole  33 , and a claw part  27 . The rear-side stopper  12  is fixed to the base  3  with the fixing screw  26  inserted into the hole  33 . A recessed portion  28  is formed in the principal part  22 . The front-side stopper  13  includes a principal part  23  formed with the hole  33  and having a recessed portion  29 . The front-side stopper  13  is fixed to the base  3  with the fixing screw  26  inserted into the hole  33 . Since the front-side stopper  13  is the principal part  23  having the recessed portion  29 , it can also be expressed as having the recessed portion  29 . 
     The principal part  22  of the rear-side stopper  12  restricts the foot part  6  of the carrier  4  not to move to the rear side (positive side in x-direction) and also restricts the foot part  6  of the carrier  4  not to move outward in the lateral direction (y-direction). The claw part  27  of the rear-side stopper  12  restricts movement of the foot part  6  of the carrier  4  to the upper side (positive side in z-direction) of the base  3 ; that is, it restricts the movement not to be separated from the base  3 . Two, or a pair of the rear-side stoppers  12  restrict the movement of the carrier  4  in the lateral direction (positive and negative sides in y-direction). As shown in  FIGS. 6 and 7 , the principal part  22  has the recessed portion  28 ; that is, the recessed portion  28  is formed in the principal part  22 . Further, side faces of the recessed portion  28  are opposed faces to the carrier in the principal part  22 , which face a bottom face and an outside face of the foot part  6  of the carrier  4 . The broken line shown in the rear-side stopper  12  of  FIGS. 6 and 7  indicates the side faces of the recessed portion  28 , that is, the opposed faces to the carrier. The rear-side stopper  12  includes the principal part  22  in which the recessed portion  28  is formed to restrict the movement of the foot part  6  being the plate-shaped end part of the carrier  4  to the rear side, and to restrict the movement of the foot part  6  being the plate-shaped end part to an outer side of the carrier  4  in the lateral direction that is horizontal to the base  3  and perpendicular to a direction of the front side, and includes the claw part  27  to restrict the movement of the foot part  6  being the plate-shaped end part in the direction vertical to the base  3 . 
     The front-side stopper  13  restricts the carrier  4  not to move to the front side (negative side in x-direction) and also restricts the opening edge part  7  of the carrier  4  not to move outward in the lateral direction (y-direction). Two, or a pair of the front-side stoppers  13  restrict the movement of the opening edge parts  7  of the carrier  4  in the lateral direction (positive and negative sides in y-direction). That is, the front-side stoppers  13  include the recessed portions  29  to restrict the movement of the opening edge parts  7  of the carrier  4  to the front side, and to restrict the movement of the opening edge parts  7  to the outer side of the carrier in the lateral direction that is horizontal to the base  3  and perpendicular to the direction of the front side. 
     In the positioning member  30  and the carrier placement platform  50  of Embodiment 2, similarly to the positioning member  30  and the carrier placement platform  50  of Embodiment 1, the rear-side stoppers  12  restrict the foot parts  6  of the carrier  4  so that the carrier  4  cannot move to the rear side (positive side in the x-direction), and also restrict the foot parts  6  of the carrier  4  not to move to the upper side (positive side in the z-direction) of the base  3 ; that is, they restrict the foot parts not to be separated from the base  3 , and the front-side stoppers  13  restrict the carrier  4  not to move to the front side (negative side in x-direction). Further, in the positioning member  30  and the carrier placement platform  50  of Embodiment 2, a pair of the rear-side stoppers  12  restrict the foot parts  6  of the carrier  4  not to move in the lateral direction (y-direction) owing to the recessed portions  28 , and the front-side stoppers  13  restrict the opening edge parts  7  of the carrier  4  not to move in the lateral direction (y-direction) owing to the recessed portions  29 . Since the positioning member  30  and the carrier placement platform  50  of Embodiment 2 restrict the opening edge parts  7  and the foot parts  6  of the carrier  4  not to move in the lateral direction (y-direction), the carrier  4  is not displaced laterally on the base  3  when the carrier  4  is moved from the base  3 ; that is, when the opening edge parts  7  of the carrier  4  are higher than the front-side stoppers  2 , and thus the fall of the wafer  5  caused by the lateral displacement described in  FIG. 8  can be prevented. In the positioning member  30  and the carrier placement platform  50  of Embodiment 2, when the carrier  4  is moved from the base  3 ; that is, when the opening edge parts  7  of the carrier  4  are higher than the front-side stoppers  2 , the carrier  4  is not displaced laterally on the base  3 . Therefore, the opening edge parts  7  of the carrier  4  pass the upper sides of the front-side stoppers  13  with contacting the front-side stoppers  13  or without contacting the front-side stoppers  13 , so that the carrier  4  is not tilted to the front side. 
     The positioning member  30  of Embodiment 2 is designed such that the carrier  4  is tilted to the rear side without fail when the carrier  4  is placed on the base  3  or when the carrier  4  is moved from the base  3 , and is provided with the rear-side stoppers  12  including the principal parts  22  formed with the recessed portions  28  and the front-side stoppers  13  including the recessed portions  29  that restrict the carrier  4  not to move in the front-rear direction (x-direction) and the lateral direction (y-direction). Further, the rear-side stoppers  12  include the claw parts  27  to restrict the separation of the carrier  4  from the base  3 . Therefore, in the positioning member  30  of Embodiment 2, when the carrier  4  is moved from the base  3 , the carrier  4  is not displaced laterally, the carrier  4  is not tilted to the front side by mistake, and the plate-shaped loads (wafers  5 ) can be prevented from slipping off from the carrier  4 . The carrier placement platform  50  of Embodiment 2 is designed such that the carrier  4  is tilted to the rear side without fail when the carrier  4  is placed on the base  3  or when the carrier  4  is moved from the base  3 , and is provided with the rear-side stoppers  12  including the principal parts  22  formed with the recessed portions  28  and the front-side stoppers  13  including the recessed portions  29  that restrict the carrier  4  not to move in the front-rear direction (x-direction) and the lateral direction (y-direction). Further, the rear-side stoppers  12  include the claw parts  27  to restrict the separation of the carrier  4  from the base  3 . Therefore, in the carrier placement platform  50  of Embodiment 2, when the carrier  4  is moved from the base  3 , the carrier  4  is not displaced laterally, the carrier  4  is not tilted to the front side by mistake, and the plate-shaped loads (wafers  5 ) can be prevented from slipping off from the carrier  4 . 
     Embodiment 3 
       FIG. 9  is a diagram showing a positioning member and a carrier placement platform according to Embodiment 3, and  FIG. 10  is a plan view of a rear-side stopper part of  FIG. 9 .  FIGS. 11, 12, and 13  are diagrams for explaining a method of placing the carrier on the carrier placement platform of  FIG. 9 . In the drawings, components common to Embodiments 1 and 2 are denoted by the same reference numerals and signs as those in Embodiments 1 and 2. The positioning member  30  and the carrier placement platform  50  of Embodiment 3 are different from the positioning member  30  and the carrier placement platform  50  of Embodiments 1 and 2 in that they are provided with two support members  31   a  and  31   b  instead of four stoppers. In  FIGS. 11, 12 and 13 , the base  3  is omitted. 
     The positioning member  30  includes two support members  31   a  and  31   b.  The support members  31   a  and  31   b  each include a rear-side stopper part  15 , a front-side stopper part  16 , and a guide part  17  that connects the rear-side stopper part  15  and the front-side stopper part  16  and guides the carrier  4  to the rear-side stopper part  15 . In  FIG. 9 , the direction from the front-side stopper part  16  to the rear-side stopper part  15  is the x-direction, the direction vertical to a placing face of the rear-side stopper part  15  and the front-side stopper part  16  on the base  3  is the z-direction, and the direction perpendicular to the x-direction and the z-direction are the y-direction. The support member  31   a  and the support member  31   b  are inverted in shape to each other with respect to the broken line  38  of the x-direction.  FIG. 10  shows the rear-side stopper part  15  on the positive side in the y-direction, that is, the rear-side stopper part  15  of the support member  31   a.  The rear-side stopper part  15  on the negative side in the y-direction, that is, the rear-side stopper part  15  of the support member  31   b,  has a shape in which the rear-side stopper part  15  on the positive side in the y-direction is inverted with respect to the broken line  38  of the x-direction. The front-side stopper part  16  on the negative side in the y-direction and the front-side stopper part  16  on the positive side in the y-direction are inverted in shape to each other with respect to the broken line  38  of the x direction. 
     The rear-side stopper part  15  is a part on the positive side in the x-direction from the broken line  37 , and includes the principal part  22  formed with the hole  33 , and the claw part  27 . The rear-side stopper part  15  is fixed to the base  3  with the fixing screw  26  inserted into the hole  33 . The front-side stopper part  16  is a part on the negative side in the x-direction from a broken line  39 , and includes the principal part  23  formed with the hole  33  and having the recessed portion  29 . The front-side stopper part  16  is fixed to the base  3  with the fixing screw  26  inserted into the hole  33 . Since the front-side stopper part  16  is the principal part  23  having the recessed portion  29 , it can also be expressed as having the recessed portion  29 . The guide part  17  is a part from the broken line  39  to the broken line  37 , and is the part for guiding the plate-shaped end part (foot part  6 ) of the carrier  4  to the recessed portion  28  and the claw part  27 . 
     The principal part  22  of the rear-side stopper part  15  restricts the foot part  6  of the carrier  4  not to move to the rear side (positive side in x-direction) and also restricts the foot part  6  of the carrier  4  not to move outward in the lateral direction (y-direction). The claw part  27  of the rear-side stopper part  15  restricts movement of the foot part  6  of the carrier  4  to the upper side (positive side in z-direction) of the base  3 ; that is, it restricts the foot part not to be separated from the base  3 . Two, or a pair of the rear-side stopper parts  15  of the support members  31   a  and  31   b  restrict movement of the carrier  4  in the lateral direction (positive and negative sides in y-direction). As shown in  FIGS. 9 and 10 , the principal part  22  has the recessed portion  28 ; that is, the recessed portion  28  is formed in the principal part  22 . Further, side faces of the recessed portion  28  are opposed faces to the carrier in the principal part  22 , which face a bottom face and an outside face of the foot part  6  of the carrier  4 . The broken line shown in the rea-side stopper part  15  of  FIGS. 9 and 10  indicates the side faces of the recessed portion  28 , that is, the opposed faces to the carrier. 
     The front-side stopper part  16  restricts the carrier  4  not to move to the front side (negative side in x-direction) and also restricts the opening edge part  7  of the carrier  4  not to move outward in the lateral direction (y-direction). Two, or a pair of the front-side stopper parts  16  of the support members  31   a  and  31   b  restrict movement of the opening edge parts  7  of the carrier  4  in the lateral direction (positive and negative sides in y-direction). That is, the front-side stopper parts  16  include the recessed portions  29  to restrict the movement of the opening edge parts  7  of the carrier  4  to the front side, and to restrict the movement of the opening edge parts  7  to an outer side of the carrier in the lateral direction that is horizontal to the base  3  and perpendicular to the front side direction. 
     In the positioning member  30  and the carrier placement platform  50  of Embodiment 1, when the carrier  4  is placed on the base  3 , the foot part  6  of the carrier  4  needs to be positioned on the front side of the rear-side stopper  1 , and correctly inserted into a gap between the claw part  25  and the base  3  in the rear-side stopper  1 . If the carrier  4  is moved by mistake to the rear side (positive side in x-direction) with the positions of the carrier  4  and the rear-side stopper  1  greatly displaced, since the foot part  6  of the carrier  4  does not hit the rear-side stopper  1 , the carrier  4  may further move to the rear side, and one of the rear-side stoppers  1  positioned between the two foot parts  6  may enter a portion of the side plate  41  of the carrier  4  where the foot part  6  is not present. If the wafer  5  is placed on the side of the side plate  41  (base  3  side) of the carrier  4 , the rear-side stopper  1  may collide with the wafer  5  on the side of the side plate  41 . 
     In the positioning member  30  and the carrier placement platform  50  of Embodiment 3, since the support members  31   a  and  31   b  are provided with the guide parts  17  for guiding the carrier  4  to the rear-side stopper parts  15 , the positioning of the carrier with respect to the rear-side stopper parts  15  is ensured when the carrier  4  is placed on the base  3  of the carrier placement platform  50 , and the collision between the rear-side stopper part  15  and the wafer  5  on the side of the side plate  41  can be prevented. Referring to  FIGS. 11 to 13 , a method of placing the carrier  4  on the carrier placement platform  50  of Embodiment 3 will be described. 
     When the carrier  4  is placed on the base  3  of the carrier placement platform  50 , as shown in  FIG. 11 , the foot parts  6  of the carrier  4  are inserted into inner sides of the guide parts  17  of the support members  31   a  and  31   b  as indicated by an arrow  18 . Since the opening edge parts  7  of the carrier  4  pass the upper sides of the front-side stopper parts  16  of the support members  31   a  and  31   b  with contacting the front-side stopper parts  16  or without contacting the front-side stopper parts  16 , the carrier  4  is not tilted to the front side. Next, as shown in  FIG. 12 , when the foot parts  6  of the carrier  4  are moved to the rear side (positive side in x-direction) as indicated by an arrow  19 , the guide parts  17  guide the foot parts  6  into the rear-side stopper parts  15 , and the rear-side stopper parts  15  restrict the movement of the foot parts  6  of the carrier  4 , so that the carrier  4  does not move further backward. Next, as shown in  FIG. 13 , when the carrier  4  is turned as indicated by an arrow  20  to be vertical with respect to the base  3 , the opening edge parts  7  of the carrier  4  fit into the front stopper parts  16  of the support members  31   a  and  31   b  as indicated by an arrow  21 . 
     Since the support members  31   a  and  31   b  of Embodiment 3 are provided with the rear-side stopper parts  15  having the same shape as the rear-side stoppers  12  of Embodiment 2 and the front-side stopper parts  16  having the same shape as the front-side stoppers  13  of Embodiment 2, the positioning member  30  and the carrier placement platform  50  of Embodiment 3 have the same effects as the positioning member  30  and the carrier placement platform  50  of Embodiment 2. That is, the positioning member  30  of Embodiment 3 is designed such that the carrier  4  is tilted to the rear side without fail when the carrier  4  is placed on the base  3  or when the carrier  4  is moved from the base  3 , and is provided with the rear-side stopper parts  15  including the principal parts  22  formed with the recessed portions  28  and the front-side stopper parts  16  including the recessed portions  29  that restrict the carrier  4  not to move in the front-rear direction (x-direction) and the lateral direction (y-direction). Further, the rear-side stoppers  15  include the claw parts  27  to restrict the separation of the carrier  4  from the base  3 . Therefore, in the positioning member  30  of Embodiment 3, when the carrier  4  is moved from the base  3 , the carrier  4  is not displaced laterally, the carrier  4  is not tilted to the front side by mistake, and plate-shaped loads (wafers  5 ) can be prevented from slipping off from the carrier  4 . Furthermore, in the positioning member  30  of Embodiment 3, since the support members  31   a  and  31   b  are provided with the guide parts  17  for guiding the carrier  4  to the rear-side stopper parts  15 , the positioning of the carrier with respect to the rear-side stopper parts  15  is ensured when the carrier  4  is placed on the base  3 , and the collision between the rear-side stopper part  15  and the wafer  5  on the side of the side plate  41  can be prevented. 
     The carrier placement platform  50  of Embodiment 3 is designed such that the carrier  4  is tilted to the rear side without fail when the carrier  4  is placed on the base  3  or when the carrier  4  is moved from the base  3 , and is provided with the rear-side stopper parts  15  including the principal parts  22  formed with the recessed portions  28  and the front-side stopper parts  16  including the recessed portions  29  that restrict the carrier  4  not to move in the front-rear direction (x-direction) and the lateral direction (y-direction). Further, the rear-side stoppers  15  include the claw parts  27  to restrict the separation of the carrier  4  from the base  3 . Therefore, in the carrier placement platform  50  of Embodiment 3, when the carrier  4  is moved from the base  3 , the carrier  4  is not displaced laterally, the carrier  4  is not tilted to the front side by mistake, and the plate-shaped loads (wafers  5 ) can be prevented from slipping off from the carrier  4 . Furthermore, in the carrier placement platform  50  of Embodiment 3, since the support members  31   a  and  31   b  are provided with the guide parts  17  for guiding the carrier  4  to the rear-side stopper parts  15 , the positioning of the carrier with respect to the rear-side stopper parts  15  is ensured when the carrier  4  is placed on the base  3 , and the collision between the rear-side stopper part  15  and the wafer  5  on the side of the side plate  41  can be prevented. 
     The positioning member  30  of Embodiment 3 is a carrier positioning member that is fixed to the base  3  and that positions, on the base  3 , the carrier  4  storing a plurality of the plate-shaped loads (wafers  5 ) such that the front faces or the rear faces thereof face the base  3 . A side in the opening  45  of the carrier  4  in which the plate-shaped loads (wafers  5 ) is taken in and out is the front side, and a side opposite to the opening  45  of the carrier  4  is the rear side. The positioning member  30  of Embodiment 3 is provided with a first support member  31   a  including a first front-side stopper part  16  that comes into contact with a first opening edge part  7  being one end of the opening  45  of the carrier  4  to restrict the movement of the carrier  4  to the front side, a first rear-side stopper part  15  that comes into contact with a first plate-shaped end part (foot part  6 ) formed on the rear side of the carrier  4  to restrict the movement of the carrier  4  to the rear side and the movement in the direction vertical to the base  3 , and a first guide part  17  that connects the first front-side stopper part  16  and the first rear-side stopper part  15  and guides the first plate-shaped end part (foot part  6 ) of the carrier  4  to the first rear-side stopper part  15 . Further, the positioning member  30  of Embodiment 3 is provided with a second support member  31   b  including a second front-side stopper part  16  that comes into contact with a second opening edge part  7  being the other end of the opening  45  of the carrier  4  to restrict the movement of the carrier  4  to the front side, a second rear-side stopper part  15  that comes into contact with a second plate-shaped end part (foot part  6 ) formed on the rear side of the carrier  4  to restrict the movement of the carrier  4  to the rear side and the movement in the direction vertical to the base  3 , and a second guide part  17  that connects the second front-side stopper part  16  and the second rear-side stopper part  15  and guides the second plate-shaped end part (foot part  6 ) of the carrier  4  to the second rear-side stopper part  15 . With the configuration of the positioning member  30  of Embodiment 3, since the two front-side stopper parts  16  restrict the movement of the carrier  4  to the front side and the two rear-side stopper parts  15  restrict the movement of the carrier  4  to the rear side and the movement in the direction vertical to the base  3 , when the carrier  4  is placed on the base  3  on which the positioning member  30  for the carrier is fixed or when the carrier  4  is moved from the base  3  on which the positioning member  30  for the carrier is fixed, the plate-shaped loads (wafers  5 ) can be prevented from slipping off from the carrier  4 . 
     The carrier placement platform  50  of Embodiment 3 is provided with the base  3  and the positioning member  30  fixed to the base  3 . The positioning member  30  is a carrier positioning member that is fixed to the base  3  and that positions, on the base  3 , the carrier  4  storing a plurality of the plate-shaped loads (wafers  5 ) such that the front faces or the rear faces thereof face the base  3 . The side in the opening  45  of the carrier  4  in which the plate-shaped loads (wafers  5 ) is taken in and out is the front side, and the side opposite to the opening  45  of the carrier  4  is the rear side. The positioning member  30  is provided with a first support member  31   a  including a first front-side stopper part  16  that comes into contact with a first opening edge part  7  being one end of the opening  45  of the carrier  4  to restrict the movement of the carrier  4  to the front side, a first rear-side stopper part  15  that comes into contact with a first plate-shaped end part (foot part  6 ) formed on the rear side of the carrier  4  to restrict the movement of the carrier  4  to the rear side and the movement in the direction vertical to the base  3 , and a first guide part  17  that connects the first front-side stopper part  16  and the first rear-side stopper part  15  and guides the first plate-shaped end part (foot part  6 ) of the carrier  4  to the first rear-side stopper part  15 . The positioning member  30  is provided with a second support member  31   b  including a second front-side stopper part  16  that comes into contact with a second opening edge part  7  being the other end of the opening  45  of the carrier  4  to restrict the movement of the carrier  4  to the front side, a second rear-side stopper part  15  that comes into contact with a second plate-shaped end part (foot part  6 ) formed on the rear side of the carrier  4  to restrict the movement of the carrier  4  to the rear side and the movement in the direction vertical to the base  3 , and a second guide part  17  that connects the second front-side stopper part  16  and the second rear-side stopper part  15  and guides the second plate-shaped end part (foot part  6 ) of the carrier  4  to the second rear-side stopper part  15 . With the configuration of the carrier placement platform  50  of Embodiment 3, since the two front-side stopper parts  16  restrict the movement of the carrier  4  to the front side and the two rear-side stopper parts  15  restrict the movement of the carrier  4  to the rear side and the movement in the direction vertical to the base  3 , when the carrier  4  is placed on the base  3  of the carrier placement platform  50  or when the carrier  4  is moved from the base  3  of the carrier placement platform  50 , the plate-shaped loads (wafers  5 ) can be prevented from slipping off from the carrier  4 . 
     Embodiment 4 
     Although Embodiment 3 shows an example of the positioning member  30  in which the guide part  17  connects the rear-side stopper part  15  and the front-side stopper part  16 , the guide part  17  may not be connected to the front-side stopper part  16 . That is, as shown in  FIG. 14 , the positioning member  30  may include a pair of the front-side stoppers  13 , and a pair of the rear-side stoppers  12  each having the guide part  17 .  FIG. 14  is a diagram showing the positioning member and the carrier placement platform according to Embodiment 4, and  FIG. 15  is a plan view showing a main part of the rear-side stopper of  FIG. 14 . In the drawings, components common to Embodiments 1, 2, and 3 are denoted by the same reference numerals and signs as those in Embodiments 1, 2, and 3. 
     The front-side stopper  13  is the same as the front-side stopper  13  of Embodiment 2. The rear-side stopper  12  differs from the rear-side stopper  12  of Embodiment 2 in that the rear-side stopper includes the guide part  17  on the front side (negative side in x-direction) for guiding the carrier  4  to the principal part  22  and the claw part  27 . The guide part  17  is a part on the front side from a broken line  37 . The principal part  22  is a part on the rear side from the broken line  37 . The rear-side stopper  12  includes the principal part  22 , the claw part  27 , and the guide part  17  for the guide to the principal part  22  and the claw part  27 . In  FIG. 14 , the direction from the front-side stopper  13  to the rear-side stopper  12  is the x-direction, the direction vertical to the placing face of the rear-side stopper  12  and the front-side stopper  13  on the base  3  is the z-direction, and the direction perpendicular to the x-direction and the z-direction are the y-direction.  FIG. 15  shows the main part of the rear-side stopper  12  on the positive side in the y-direction. The rear-side stopper  12  on the negative side in the y-direction has a shape in which the rear-side stopper  12  on the positive side in the y-direction is inverted with respect to the broken line  38  of the x-direction. The front-side stopper  13  on the negative side in the y-direction and the front-side stopper  13  on the positive side in the y-direction are inverted in shape to each other with respect to the broken line  38  in the x-direction. 
     Since the rear-side stoppers  12  of the positioning member  30  and the carrier placement platform  50  of Embodiment 4 are provided with the same guide parts  17  as that of Embodiment 3, the positioning member  30  and the carrier placement platform  50  of Embodiment 4 have the same effects as those of the positioning member  30  and the carrier placement platform  50  of Embodiment 3. That is, the positioning member  30  of Embodiment 4 is designed such that the carrier  4  is tilted to the rear side without fail when the carrier  4  is placed on the base  3  or when the carrier  4  is moved from the base  3 , and is provided with the rear-side stoppers  12  and the front-side stoppers  13  which restrict the carrier  4  not to move in the front-rear direction (x-direction) and the lateral direction (y-direction), the rear-side stoppers including the principal parts  22  formed with the recessed portions  28  and the front-side stoppers including the recessed portions  29 . Further, the rear-side stoppers  12  include the claw parts  27  to restrict the separation of the carrier  4  from the base  3 . Therefore, in the positioning member  30  of Embodiment 4, when the carrier  4  is moved from the base  3 , the carrier  4  is not displaced laterally, the carrier  4  is not tilted to the front side by mistake, and the plate-shaped loads (wafers  5 ) can be prevented from slipping off from the carrier  4 . Furthermore, in the positioning member  30  of Embodiment 4, since the rear-side stoppers  12  are provided with the guide parts  17  for guiding the carrier  4  to the recessed portions  28  and the claw parts  27 , the positioning of the carrier with respect the principal parts  22  and the claw parts  27  is ensured when the carrier  4  is placed on the base  3 , and the collision of the principal part  22  and the claw part  27  with the wafer  5  on the side of the side plate  41  can be prevented. 
     The carrier placement platform  50  of Embodiment 4 is designed such that the carrier  4  is tilted to the rear side without fail when the carrier  4  is placed on the base  3  or when the carrier  4  is moved from the base  3 , and is provided with the rear-side stoppers  12  and the front-side stoppers  13  that restrict the carrier  4  not to move in the front-rear direction (x-direction) and the lateral direction (y-direction), the rear-side stoppers including the principal parts  22  formed with the recessed portions  28  and the front-side stoppers including the recessed portions  29 . Further, the rear-side stoppers  12  include the claw parts  27  to restrict the separation of the carrier  4  from the base  3 . Therefore, in the carrier placement platform  50  of Embodiment 4, when the carrier  4  is moved from the base  3 , the carrier  4  is not displaced laterally, the carrier  4  is not tilted to the front side by mistake, and the plate-shaped loads (wafers  5 ) can be prevented from slipping off from the carrier  4 . Furthermore, in the carrier placement platform  50  of Embodiment 4, since the rear-side stoppers  12  are provided with the guide parts  17  for guiding the carrier  4  to the recessed portions  28  and the claw parts  27 , the positioning of the carrier with respect the principal parts  22  and the claw parts  27  is ensured when the carrier  4  is placed on the base  3 , and the collision of the principal part  22  and the claw part  27  with the wafer  5  on the side of the side plate  41  can be prevented. 
     Note that, although various exemplary embodiments and examples are described in the present application, various features, aspects, and functions described in one or more embodiments are not inherent in a particular embodiment, and can be applicable alone or in their various combinations to each embodiment. Accordingly, countless variations that are not illustrated are envisaged within the scope of the art disclosed herein. For example, the case where at least one component is modified, added or omitted, and the case where at least one component is extracted and combined with a component in another embodiment are included. 
     DESCRIPTION OF REFERENCE NUMERALS AND SIGNS 
       1 : rear-side stopper,  2 : front-side stopper,  3 : base,  4 : carrier,  5 : wafer (plate-shaped load),  6 : foot part (plate-shaped end part),  7 : opening edge part,  12 : rear-side stopper,  13 : front-side stopper,  15 : rear-side stopper part,  16 : front-side stopper part,  17 : guide part,  22 : principal part,  25 ,  27 : claw part,  28 ,  29 : recessed portion,  30 : positioning member,  31   a,    31   b : support member,  45 : opening,  50 : carrier placement platform