Abstract:
A pod cover removing-installing apparatus can open and close any covers for a variety of pods made by a various manufactures, can satisfy an allowable distortion error capable of being normally operated even if conditions such as temperature, humidity, and can remove and install the cover without causing it to collide with any one of the parts of the pods. The pod cover removing-installing apparatus to remove and install a cover  203  for an opening  202  of a pod  200,  of which the inside is kept extremely clean, by causing the cover to engage a door  13  for an opening  12  of a high cleanliness room, while maintaining high cleanliness of the pod and the room by closely attaching the circumference of the two openings. The apparatus is provided with positioning pins  14   a,    14   b  for positioning the cover  13,  a fine adjustment mechanism  20  for fine adjustment of the positioning pins  14   a,    14   b,  and a holding mechanism  40  for holding the position of the cover  13  engaging the positioning pins  14   a,    14   b.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a pod cover removing-installing apparatus for a pod which contains and transfers thin substrates such as semiconductor wafers from one space to another space while maintaining the cleanliness of both spaces.  
           [0003]    2. Description of the Background Art  
           [0004]    [0004]FIG. 21 shows an example of a conventional pod cover removing-installing apparatus.  
           [0005]    This conventional pod cover removing-installing apparatus  100  is provided with a diaphragm  101  which partitions off a high clean space A and a low clean space B, an opening  102  formed in the diaphragm  101  and providing a passage between the high clean space A and the low clean space B, a door  103  which opens and closes the opening  102  of the diaphragm  101 , a latch mechanism  104  for latching the cover  203  of the pod  200 , which has two positioning pins  104   a,    104   b  and two T-shaped keys  104   c,    104   d  provided in the door  103 , and a table  105  provided in the low clean space B for mounting the pod  200 , which has three positioning pins  105   a,    105   b,    105   c  and one lock key  105   d.    
           [0006]    The pod  200  is a container with an extremely clean internal space C for containing a plurality of semiconductor wafers (25 wafers, for example).  
           [0007]    This pod  200  is provided with a main container body  201 , an opening  202  provided on one side of the main container body  201 , a cover  203  for opening and closing the opening  202 , having pin holes  204   a,    204   b  for engaging the positioning pins  104   a,    104   b,  and key holes  204   c,    204   d  for engaging T-shaped keys  104   c,    104   d,  and a bottom  205  having grooves  205   a,    205   b,    205   c  possessing a V-shaped section for engaging the positioning pins  105   a,    105   b,    105   c,  and a key hole  205   d  for engaging the lock key  105   d.    
           [0008]    When the pod  200  is placed on the table  105 , the three positioning pins  105   a,    105   b,    105   c  engage the V-shaped section-possessing grooves  205   a,    205   b,    205   c.  In this instance, switching on a lock button, not shown in the drawing, causes the lock key  105   d  to move upward, become angled, and engage the key hole  205   d.  Then, the table  105  moves toward the diaphragm  101  for a prescribed distance (about 30 mm), thereby causing the pod  200  to become attached to the diaphragm  101 . A sealing material such as an O-ring, not shown in the figure, is provided along the circumference of the opening  102  of the diaphragm  101  and the opening  202  of the pod  200 , to ensure close attachment of the openings and maintain cleanliness.  
           [0009]    The movement of the table  105  causes the cover  203  of the pod  200  to become closely attached to the door  203 , whereby the positioning pins  104   a,    104   b  engage the pin holes  204   a,    204   b  of the cover  203  and the T-shaped keys  104   c,    104   d  engage the key holes  204   c,    204   d.  Thereafter, the T-shaped keys  104   c,    104   d  are rotated 90° by a rotary actuator or the like, not shown in the figure, whereby nails  204   e  to  204   h  are pulled in to release the lock between the container main body  201  and the cover  203 .  
           [0010]    Then, the door  103  is pulled into the space A (arrow D 1 ) and caused to descend (arrow D 2 ) by a drive mechanism, not shown in the figure, whereby the internal space C of the pod  200  and the internal space A of the partition board  101  are brought into communication while maintaining cleanliness.  
           [0011]    In the conventional technology mentioned above, the pod  200  is made from a resin by molding. Because the formed article may be distorted depending on molding conditions or temperatures, the positioning pins  104   a,    104   b,  the pin holes  204   a,    204   b  of the cover  203 , and the key holes  204   c,    204   d  are tapered to ensure a smooth removing-installing operation.  
           [0012]    However, when wafers with a large diameter exceeding 300 mm are placed in the pod  200 , a very stringent standard is necessary to secure an allowable distortion error of ±0.5 mm. For this reason, significant difficulties may be encountered for performing the above operation in a stable manner. The following countermeasures are considered to overcome this problem.  
           [0013]    (A) One method is to precisely fabricate and adjust each pair of the main container body  201  and cover  203 , and assemble the apparatus using such a pair of the main container body  201  and cover  203 . However, this method requires readjustment of the apparatus when another pod is used.  
           [0014]    (B) Another method is to absorb a deviation between the main container body  201  and the cover  203  by designing the main container body  201  to be slightly movable. This method is effective for a small distortion, but ineffective for a large distortion. For example, even if there are no problems when the apparatus is new, distortions will be produced in two or three years after fabrication and the apparatus may not operate smoothly as time goes by.  
           [0015]    An object of the present invention is to provide a pod cover removing-installing apparatus for a pod which can open and close any covers for a variety of pods made by a various manufactures according to the SEMI standard, can satisfy an allowable distortion error capable of being normally operated even if conditions such as temperature, humidity, and use for such a variety of pods made by a various manufactures change, and can remove and install the cover without causing it to collide with any one of the parts of the pods.  
         SUMMARY OF THE INVENTION  
         [0016]    To achieve the above object, a first invention provides a pod cover removing-installing apparatus to remove and install a cover for an opening of a pod, of which the inside is kept extremely clean, by causing the cover to engage a door for an opening of a high cleanliness room, while maintaining high cleanliness of the pod and the room by closely attaching the circumference of the two openings, wherein the cover removing-installing apparatus comprises a positioning member to determine the position of the cover, a fine adjustment mechanism to finely adjust the position of the positioning member, and a holding mechanism to hold the position of the cover mated with the door by the positioning member.  
           [0017]    A second invention provides the cover removing-installing apparatus described in the first invention, wherein the door is provided with a base plate and a position adjusting plate movable in the direction vertical to the plane, the positioning member is provided in the position adjusting plate, the fine adjustment mechanism is provided in the base plate and supports the position adjusting plate movable in the direction vertical to the plane, and the holding mechanism is provided in the base plate and holds the position of the position adjusting plate.  
           [0018]    A third invention provides the cover removing-installing apparatus of the second invention, further having a centering mechanism for returning the positioning adjusting plate to the center.  
           [0019]    A fourth invention provides the cover removing-installing apparatus of the second invention, further provided with a locking member which is provided in the position adjusting plate, rotates around the axis of the position adjusting plate, and engages the cover for locking or unlocking, a lock drive means which is provided on the base plate side to rotate the lock member, and an eccentric transmission mechanism which transmits the rotational power of the lock drive means to the lock member while allowing a deviation of the base plate and position adjusting plate in the direction vertical to the plane.  
           [0020]    A fifth invention provides the cover removing-installing apparatus of the first to fourth inventions, wherein the holding mechanism cancels the holding of the position adjusting plate before the locking means locks the cover and holds the position adjusting plate after the lock member locks the cover.  
           [0021]    A sixth invention provides the pod cover removing-installing apparatus according to any one of the first to fifth inventions, wherein the lock member cancels the lock in an initial stage of the inserting operation for inserting the cover into the opening of the pod.  
           [0022]    A seventh invention provides a pod cover removing-installing apparatus to remove and install a cover for an opening of a pod, of which the inside is kept extremely clean, by causing the cover to engage a door for an opening of a high cleanliness room, while maintaining high cleanliness of the pod and the room by closely attaching the circumference of the two openings, wherein the cover removing-installing apparatus comprises a lock member to lock the cover by engaging the same and a cover securing means to secure the cover to the door by retracting the lock member to the door side.  
           [0023]    An eighth invention provides a pod cover removing-installing apparatus to remove and install a cover for an opening of a pod, of which the inside is kept extremely clean, by causing the cover to engage a door for an opening of a high cleanliness room, while maintaining high cleanliness of the pod and the room by closely attaching the circumference of the two openings, wherein the cover removing-installing apparatus comprises a positioning member to determine the position of the cover by engaging the engaged part of the cover and a position securing means to position and secure the positioning member to the engaged part of the cover by changing the external diameter of the positioning member.  
           [0024]    A ninth invention provides the pod cover removing-installing apparatus according to the eight invention, wherein the position securing means is provided in the circumference of the positioning member and has a stretch member capable of stretching according to an increase or decrease in the internal pressure.  
           [0025]    A tenth invention provided the pod cover removing-installing apparatus according to the eight invention, wherein the position securing means is formed in the positioning member and has a broken part to change the diameter thereof by a mechanical force.  
           [0026]    An eleventh invention provides the pod cover removing-installing apparatus according to any one of the first to tenth inventions, wherein the positioning member has an outer casing with a tapered end, an inner casing installed freely movably in the axial direction of the outer casing, having a taper with the same angle as the taper of the outer casing at its end, and arranged so that the two tapers become continuous when protruding, and a pushing means to push the inner casing in the protruding direction.  
           [0027]    A twelfth invention provides the pod cover removing-installing apparatus according to any one of the first to eleventh inventions, further comprising a linking posture corrective means which corrects the linking posture of the pod, a pod table having the pod installed thereon to carry the positioning member to the linking position, a securing means to secure the pod on the pod table, containing a V-section groove provided on the bottom of the pod and a linking pin provided on the pod table for engaging the V-section groove, wherein the linking posture corrective means is provided in the range in which the linking pin and the V-section groove can come into contact with each other and constitutes a fixed plane almost vertical to the moving direction of the pod table.  
           [0028]    A thirteenth invention provides the pod cover removing-installing apparatus according to any one of the first to eleventh inventions, further comprising a linking posture corrective means which corrects the linking posture of the pod, wherein the linking posture corrective means comprises a pressing member provided on the periphery of the door to press the top and/or the side of the cover of the pod and capable of freely moving in the moving direction of the table or in the vertical direction thereto within a prescribed movable range. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]    [0029]FIG. 1 is a perspective view showing an outline of a first embodiment of the cover removing-installing apparatus for a pod of the present invention.  
         [0030]    [0030]FIG. 2 is a front view of the first embodiment of the cover removing-installing apparatus for a pod of the present invention.  
         [0031]    [0031]FIG. 3 is an enlarged view of the part III of FIG. 2 and shows the fine adjustment mechanism for the pod cover removing-installing apparatus of the first embodiment.  
         [0032]    [0032]FIG. 4 is an enlarged view of the part IV of FIG. 2 and shows the centering mechanism for the pod cover removing-installing apparatus of the first embodiment.  
         [0033]    [0033]FIG. 5 is a cross sectional view along the line V-V of FIG. 2 and shows the holding mechanism of the pod cover removing-installing apparatus of the first embodiment.  
         [0034]    [0034]FIG. 6( a ) is a perspective view and FIG. 6( b ) is a cross sectional view along the line VI-VI of FIG. 2, showing an eccentric transmission mechanism for the pod cover removing-installing apparatus of the first embodiment.  
         [0035]    [0035]FIG. 7 is a cross sectional view along the line VII-VII of FIG. 2 and shows the positioning securing means of the pod cover removing-installing apparatus of the first embodiment.  
         [0036]    [0036]FIG. 8 is a block diagram showing a control means for the pod cover removing-installing apparatus of the first embodiment.  
         [0037]    [0037]FIG. 9 is a flowchart showing an operational example (cover opening operation  1 ) for the pod cover removing-installing apparatus of the first embodiment.  
         [0038]    [0038]FIG. 10 is a flowchart showing an operational example (cover opening operation  2 ) for the pod cover removing-installing apparatus of the first embodiment.  
         [0039]    [0039]FIG. 11 is a flowchart showing an operational example (cover closing operation  1 ) for the pod cover removing-installing apparatus of the first embodiment.  
         [0040]    [0040]FIG. 12 is a flowchart showing an operational example (cover opening operation  2 ) for the pod cover removing-installing apparatus of the first embodiment.  
         [0041]    [0041]FIG. 13 is a front view showing the main part of a second embodiment of the cover removing-installing apparatus for a pod of the present invention.  
         [0042]    [0042]FIG. 14 are drawings showing the main part of the second embodiment of the pod cover removing-installing apparatus of the present invention, wherein FIG. 14( a ) is a cross sectional view along the line A-A of FIG. 13 and FIG. 14( b ) is a cross sectional view along the line B-B of FIG. 13.  
         [0043]    [0043]FIG. 15 are drawings showing the main part of the second embodiment of the pod cover removing-installing apparatus of the present invention, wherein FIG. 15( a ) is a drawing viewed from the arrow E in FIG. 15( b ) and FIG. 15( a ) is a cross sectional view along the line C-C of FIG. 13.  
         [0044]    [0044]FIG. 16 is a cross sectional view along the line D-D of FIG. 13 showing the main part of the second embodiment of the cover removing-installing apparatus for a pod of the present invention.  
         [0045]    [0045]FIG. 17 shows a holding mechanism of the pod cover removing-installing apparatus according to the third embodiment.  
         [0046]    [0046]FIG. 18 shows a positioning member of the pod cover removing-installing apparatus according to the fourth embodiment.  
         [0047]    [0047]FIG. 19 shows a table positioning member of the pod cover removing-installing apparatus according to the fifth embodiment.  
         [0048]    [0048]FIG. 20 shows a positioning member of the pod cover removing-installing apparatus according to the sixth embodiment.  
         [0049]    [0049]FIG. 21 shows an example of a conventional pod cover removing-installing apparatus. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0050]    The present invention will be described in more detail by way of preferred embodiments with reference to the attached drawings.  
         [0051]    (First Embodiment)  
         [0052]    [0052]FIGS. 1 and 2 are drawings showing a first embodiment of the pod cover removing-installing apparatus of the present invention, wherein FIG. 1 is a perspective view showing an outline and FIG. 2 is a plan view of the apparatus.  
         [0053]    This pod cover removing-installing apparatus is provided with a diaphragm  11 , an opening  12 , a door  13  which opens and closes the opening  12  of the diaphragm  11 , two positioning pins  14   a,    14   b  and two T-shaped keys  14   c,    14   d,  a latch mechanism  14  which opens and closes a cover  203  of a pod  200 , and the like.  
         [0054]    In the first embodiment, the door  13  is provided with a base plate  13 A and a position adjusting plate  13 B movable in the direction vertical to the plane so that its position can be adjusted with respect to the base plate  13 .  
         [0055]    The door  13  is provided therein with four fine adjustment mechanisms  20 , two centering mechanisms  30 , four holding mechanisms  40 , two eccentric transmission mechanisms  50 , one positioning fixing means  60 , and the like.  
         [0056]    [0056]FIG. 3 is an enlarged view of the part III of FIG. 2 and shows the fine adjustment mechanism for the pod cover removing-installing apparatus of the first embodiment.  
         [0057]    The fine adjustment mechanism  20  supports the position adjusting plate  13 B movable in the direction vertical to the plane and exactly adjusts the position of the positioning pins  14   a  and  14   b.  This fine adjustment mechanism  20  is provided in the four corners of the position adjusting plate  13 B (see FIG. 1), each having a fixture  21  for fastening and securing the base plate  13 A using a thread  21   a,  a female screw  22  for keeping the fixture  21  from loosening, a receiving member  23  of free bearings and the like inserted into the fixture  21 , a ball  24  rotatively supported by the receiving member  23 , an opposing plate  25  provided in the base plate frame  13 A- 1  on the opposing side, a receiving member  26  provided in the opposing plate  25 , a ball  27  rotatively supported in the receiving member  26 , a guide plate  28  provided on the side of position adjusting plate  13 B and movably squeezed by the ball  24  and the ball  27 .  
         [0058]    The fine adjustment mechanism  20  is designed so that in the initial state in which the positioning pins  14   a,    14   b  engage the pin holes  204   a,    204   b  of the pod  200  (see FIG. 21), tapered tips of the positioning pins  14   a,    14   b  move a prescribed distance (e.g. 3 mm in every direction) vertically to the plane, while the tapered tips match the tapered pin holes  204   a,    204   b.  For this reason, even if there is some error in the position of the pin holes  204   a,    204   b  of the pod  200 , the positioning pins  14   a,    14   b  can easily engage these pin holes without colliding.  
         [0059]    [0059]FIG. 4 is an enlarged view of the part IV of FIG. 2 and shows the centering mechanism for the pod cover removing-installing apparatus of the first embodiment.  
         [0060]    The centering mechanism  30  is a mechanism for causing the position adjusting plate  13 B to return to the center. The centering mechanism  30 , consisting of two systems, one in the horizontal direction (x direction) and the other in the vertical direction (y direction), is provided with press boards  31   x,    31   y,  securing members  32   x,    32   y  for securing the press boards  31   x,    31   y  in the base plate  13 A, coil springs  33   x,    33   y  for moving the press boards  31   x,    31   y  to the center, securing members  34   x,    34   y  for securing the other ends of the coil springs  33   x,    33   y  to the base plate  13 A, guide pieces  35 ,  37  which come into contact with the press boards  31   x,    31   y,  securing members  36 ,  38  for securing the guide pieces  35 ,  37  in the position adjusting plate  13 B and base plate  13 A, and the like.  
         [0061]    The press board  31   x  aligns the guide pieces  35 ,  37  on a straight line in the X direction. In the same manner, the press board  31   y  aligns the guide pieces  35 ,  37  on a straight line in the Y direction. The position adjusting plate  13 B is centered by these actions.  
         [0062]    Although omitted from FIG. 2, a mechanism which is the same but symmetrical with the mechanism shown in the upper right side is provided in the upper left side of the FIG. 2.  
         [0063]    Because the position adjusting plate  13 B can move vertical to the plane with respect to the base plate  13 A by means of the fine adjustment mechanism  20 , the centering mechanism  30  always causes the position adjusting plate  13 B to be positioned in the previously determined center position (the engaging position without an error) in the initial state in which the positioning pins  14   a ,  14   b  engage the pin holes  204   a,    204   b  of the pod  200  (see FIG. 21).  
         [0064]    [0064]FIG. 5 is a cross sectional view along the line V-V of FIG. 2 and shows the holding mechanism of the pod cover removing-installing apparatus of the first embodiment.  
         [0065]    The holding mechanism  40  holds the position adjusting plate  13 B to the cover  203  of the pod  200  at the position where the positioning pins  14   a,    14   b  engage. The holding mechanism  40  has a securing plate  41  provided in a base plate frame  13 A- 1 , a joint  43  connected with this securing plate  41  through the O-ring  42 , having a nozzle (not shown in the figure) connected to a vacuum pressure source, and an absorption pad  44  provided in the joint  43  which is capable of being attached to the position adjusting plate  13 B.  
         [0066]    Because the position adjusting plate  13 B can move vertical to the plane with respect to the base plate  13 A by means of the fine adjustment mechanism  20 , the holding mechanism  40  can hold the positioning pins  14   a,    14   b  to engage the pin holes  204   a,    204   b  of the pod  200  (see FIG. 21). This structure ensures that the container maintains the same position as the position before removal when the cover  203  has been once removed and returned thereafter. Therefore, the cover can be closed without impediment.  
         [0067]    [0067]FIG. 6( a ) is a perspective view and FIG. 6( b ) is a cross sectional view along the line VI-VI of FIG. 2, showing an eccentric transmission mechanism for the pod cover removing-installing apparatus of the first embodiment.  
         [0068]    The T-shaped key  14   c  ( 14   d ) is provided in a prescribed position of the position adjusting plate  13 B to engage the key hole  204   c  ( 204   d ) of the cover  203  to lock the cover  203 , and driven by a lock drive mechanism  70  (see FIG. 2). This lock drive mechanism  70  is provided on the side of the base plate  13 A and rotates in either direction around the axis of the T-shaped key  14   c  ( 14   d ) to perform locking or unlocking movements.  
         [0069]    Because it is desirable to make the position adjusting plate  13 B light for ease of movement, the lock drive mechanism  70  and the like are preferably installed on the base plate  13 A. For this reason, an eccentric transmission mechanism  50  is provided to transmit a driving force from the lock drive mechanism  70  to the T-shaped key  14   c  ( 14   d ).  
         [0070]    This eccentric transmission mechanism  50  allows a deflection of the base plate  13 A and position adjusting plate  13 B in the direction vertical to the plane and transmits a rotational force of the lock drive mechanism  70  to the T-shaped key (locking member)  14   c  ( 14   d ).  
         [0071]    As shown in FIG. 6, the eccentric transmission mechanism  50  has a driving lever  51  connected to the lock drive mechanism  70 , a rotation lever  52  rotatively connected to the driving lever  51 , a bearing  54  supporting the rotation lever  52  on the base plate  13 A in a freely rotative manner, transmission rollers  53 A,  53 B provided on the rotation lever  52 , a slide disc  55  having grooves  55   a,    55   b  orthogonally provided on both sides, into which the transmission rollers  53 A,  53 B and transmission rollers  56 A,  56 B are respectively inserted, a rotation board  57  provided on the same axis with the T-shaped key  14   c  ( 14   d ), a bearing  58  having the transmission rollers  56 A,  56 B provided therein and supporting the axis of the rotation board  57  and the T-shaped key  14   c  ( 14   d ) on the position adjusting plate  13 B in a freely rotative manner, and the like.  
         [0072]    The eccentric transmission mechanism  50  transmits a rotational force of the lock drive mechanism  70  to the T-shaped key  14   c  ( 14   d ), even if the position adjusting plate  13 B moves from its original position within a movable range in the direction vertical to the plane.  
         [0073]    Here, as shown in FIG. 2, the lock drive mechanism  70  is provided with a motor  71 , a drive screw  73  to which the rotation of the motor  71  is transmitted by a belt  72 , a slide axis  74  arranged in parallel with the drive screw  73 , a moving block  75  freely slidably supported in the slide axis  74  and driven by a drive screw  73 , a bearing  76  secured on a moving block  75  and engaging a long hole in the transmission lever  51 , and the like.  
         [0074]    When the bearing  76  is in the position (a), the rotation lever  52  is in the position (a). When the bearing  76  moves to the right and comes to the position (b), the rotation lever  52  rotates. This causes the transmission lever  51  to move that distance and to descend to the point indicated by a chain line connected by two dots. Because the bearing  76  is secured on the moving block  75 , the horizontal level of the position (b) remains the same as that of the position (a). Because of this, a deviation of the engaging position of the transmission lever  51  and the bearing  76  is absorbed by the long hole of the transmission lever  51 .  
         [0075]    [0075]FIG. 7 is a cross sectional view along the line VII-VII of FIG. 2 and shows the positioning securing means of the pod cover removing-installing apparatus of the first embodiment.  
         [0076]    The position securing means  60  secures the positioning pins  14   a,    14   b  in the pin holes  204   a,    204   b  when the positioning pins  14   a,    14   b  engage the pin holes (the parts to be engaged)  204   a  and  204   b  of the pod  200  and their positions are determined.  
         [0077]    The position securing means  60  of this embodiment has a passage  61  provided in the axial direction of the positioning pin  14   a  ( 14   b ), a passage  62  provided in the vertical direction of the passage  61  and joining therewith, a stretch member  63  formed from rubber such as neoprene provided around the circumference of the positioning pin  14   a  ( 14   b ) and capable of stretching according to an increase or decrease in the internal pressure, a pipe  64  connected with the passage  61 , a securing member  65  for securing the pipe  64  at the rear end of the positioning pin  14   a  ( 14   b ), and the like.  
         [0078]    In this position securing means  60 , pipe  64  is connected to a pneumatic circuit or a vacuum circuit, not shown in the figure, which causes the internal pressure of the passages  61 ,  62  to increase or decrease, thereby causing the stretch member  63  to expand or contract, causing the gap between the positioning pins  14   a,    14   b  and the pin holes  204   a,    204   b  to be filled out. The positioning pins  14   a,    14   b  are secured in the position in this manner.  
         [0079]    [0079]FIG. 8 is a block diagram showing a control means for the pod cover removing-installing apparatus of the first embodiment, and FIGS.  9 - 12  are flow charts showing operations of the cover removing-installing apparatus.  
         [0080]    The control means  80  has various sensors  81  for detecting the positions and the like of each moving part, a controller  82  which produces various control signals to control each drive part, described later, based on the position detection signals from the sensors  81 , a driver  83  for converting control signals from the controller  82  into drive signals conforming to each drive part, and a drive part driven based on the drive signals from the driver  83 , including a position-keeping valve  84  which controls the flow of the air pressure to the holding mechanism  40 , a cover securing valve  85  which controls the flow of the air pressure to a cover securing means  60 , a cover locking motor  71  of a lock drive means  70 , a container moving motor  86 , a door moving motor  87 , and the like.  
         [0081]    Next, the cover opening operation will be described referring to FIGS. 9 and 10.  
         [0082]    The controller  82  drives the position-keeping valve  84  to the release side (Step  101 , the step is hereinafter referred to as “S”) and, upon confirmation of release with a sensor (S 102 , YES), drives the container moving motor  86  to move the pod  200  forward (S 103 ), then, upon confirmation that the pod  200  has come to the joining position (S 104 , YES), stops the container moving motor  86 .  
         [0083]    Because the holding mechanism  40  is canceled in this state by the position-keeping valve  84 , the position adjusting plate  13 B is not only free, but also has been moved to the center by the centering mechanism  30 . When the pod  200  comes to the joining point, the position adjusting plate  13 B can be moved by the fine adjustment mechanism  20 , enabling the complete joining of the cover  203  of the pod  200  and the door  13  even though the pin holes  204   a  and  204   b  of the pod  200  deviate in the allowable range with respect to the positioning pins  14   a,    14   b.    
         [0084]    Next, the cover locking motor  71  is driven to the unlock side (S 105 ) and the T-shaped keys  14   c  and  14   d  are rotated to retract the nails  204   e - 204   h  of the cover  203 . When the sensor confirms that the nails  204   e - 204   h  have been retracted (unlock) (S 106 , YES), the cover securing valve  85  is driven to the securing side (S 107 ) to expand the stretch member  63  of the positioning pins  14   a,    14   b,  confirming the securing of the pin holes  204   a,    204   b  with the sensor (S 108 , YES).  
         [0085]    In the final stage of the operation S 107 , even if there is a deviation between the positioning pins  14   a,    14   b  and pin holes  204   a,    204   b,  and the position adjusting plate  13 B has been moved, the T-shaped keys  14   c,    14   d  can rotate due to the eccentric transmission mechanism  50 .  
         [0086]    Moreover, accurate positioning is possible because the pin holes  204   a,    204   b  are secured by expanding the stretch member  63  of the positioning pins  14   a,    14   b.    
         [0087]    Next, as shown in FIG. 10, the position-keeping valve  84  is driven to the hold side (S 109 ), confirming the holding with the sensor (S 110 , YES), and causing the door to reverse by driving the door moving motor  87  (S 111 ). Upon confirmation that the door has reversed (S 112 , YES), the door moving motor  87  is further driven to move the door downward (S 113 ). When the door has reached the lower limit (S 114 , YES), the operation to terminate the process is stopped.  
         [0088]    In this state, the position-keeping valve  84  is driven to the hold side and holds the position of the position adjusting plate  13 B in its original position in the later-described door closing operation. Therefore, the door does not collide with the opening  202  of the pod  200  when closed.  
         [0089]    Next, the cover closing operation will be described referring to FIGS. 11 and 12.  
         [0090]    Referring to FIG. 11, the controller  82  drives the door moving motor  87  to elevate (S 201 ) to the upper limit point (S 202 , YES), then to go forward (S 203 ) until it starts rejoining the pod  200 . Upon confirmation of the initiation of rejoining by a sensor (S 204 , YES), the position-keeping valve  84  is driven to the release side (S 205 ). Upon confirmation of the release by a sensor (S 206 , YES), the door moving motor  87  is driven forward (S 207 ) until rejoining is complete, whereupon the door moving motor  87  is stopped and the rejoining with the pod  200  is confirmed by a sensor (S 208 ).  
         [0091]    Next, the cover securing valve  85  is driven to the release side (S 209 ) to cause the stretch member  63  of the positioning pins  14   a,    14   b  to become contracted. The release from the pin holes  204   a,    204   b  is confirmed by a sensor (S 210 , YES). The cover locking motor  71  is driven to the lock side (S 211 ) to rotate the T-shaped keys  104   c,    104   d  and cause the nails  204   e  to  204   h  to protrude and lock the cover, which is confirmed by a sensor (S 212 , YES).  
         [0092]    Finally, the container moving motor  86  is driven to move the pod  200  backward (S 213 ). Upon confirmation by a sensor that the pod  200  has reversed (S 104 , YES), the container moving motor  86  is stopped to terminate the cover closing operation.  
         [0093]    (Second Embodiment)  
         [0094]    FIGS.  13 - 16  show the main parts of the pod cover removing-installing apparatus of the second embodiment, wherein FIG. 13 is a front view, FIG. 14( a ) is a cross sectional view along the line A-A of FIG. 13, FIG. 14( b ) is a cross sectional view along the line B-B of FIG. 13, FIG. 15( a ) is a view from the direction of the arrow E of FIG. 15( b ), FIG. 15( b ) is a cross sectional view along the line C-C of FIG. 13, and FIG. 16 is a cross sectional view along the line D-D of FIG. 13.  
         [0095]    The second embodiment of the pod cover removing-installing apparatus has, in addition to the structure of the first embodiment, a cover securing means which secures the cover  203  to the door  13  by retracting the lock pins  13   a,    13   b  (by pulling down in FIG. 13) to the door  13  side.  
         [0096]    A linear motion from a drive means, not shown in the drawing, to a rack  312  in FIG. 13 rotates a pinion gear  311  which engages the rack  312 . A disc  310  is coaxially screwed to the pinion gear  311 .  
         [0097]    The disc  310  can rotate by 180°, causing the T-shaped key  14   c  ( 14   d ) to rotate in the first 90° rotation and drawing the T-shaped key  14   c  ( 14   d ) to the direction of the arrow F in the next 90° rotation, thereby securing the cover  203  to the door  13 . (the cover securing means).  
         [0098]    A disc  309  is installed on an axis  309   a  in a freely rotative manner within an angle of 90°. The axis  309   a  is screwed to the base plate  13 A. A rotation from the disc  310  is transmitted to the disc  309  via a rotor (bearing) which is screwed to the groove formed on the bottom of the disc  309  and the top of the disc  310 .  
         [0099]    A rotating disc  306  is connected to the rotating disc  309  via a moving body  308  and a bearing  307 , as shown in FIG. 14( a ). The moving body  308  and the bearing  307  allow the rotation of the rotating disc  309  and the rotating disc  306 , even if these deviate in any direction, i.e. up and down, right and left, or front and back.  
         [0100]    Because not only the disc  305  is connected to the disc  306  via a support  320  and a bush  321  (FIG. 13), but also these parts are pressed together by a spring, the discs  305  and  306  rotate as an integral body.  
         [0101]    The T-shaped key  14   c  ( 14   d ) is held on a holding base  302  movable in the axial direction. A push-down board  303  is connected to the holding base  302 . The push-down board  303  is provided with a bearing  304  which maintains contact with the surface of the disc  305  while rotating. The disc  305  is pushed upward by the spring  301 . The contact of the disc  305  with the holding base  302  ensures accurate determination of the position of the T-shaped key  14   c  ( 14   d ) in the axial direction.  
         [0102]    The T-shaped key  14   c  ( 14   d ) rotates 90° by a first 90° rotation of the disc  310  according to the above mechanism to complete a lock (or unlock) operation. In this instance, the rotation can be transmitted even if the rotating disc  309  and the rotating disc  306  deviate in any direction (up and down, right and left, or front and back) due to the existence of the moving body  308  and the bearing  307  (eccentric transmission mechanism).  
         [0103]    As shown in FIGS. 13 and 15, a roller  318  is attached to a bracket  322  provided in the base plate  13 A and comes into contact with the bottom of the disc  310  to prevent downward deflection of the disc  310 .  
         [0104]    A groove  310   a  is formed on the surface of the disc  310  as shown in FIG. 16( b ). The bottom of the groove  310   a  slopes from the highest point  311   b  to the lowest point  310   c.  A bearing  313  enters the groove  310   a  and moves. The bearing  313  is installed on the bottom of the support member  324  which is provided in a freely slidable manner in the collar  323  installed on the bracket  322 . The support member  324  has a cylindrical upper portion into which a support column  316  is inserted through a spring  315 . A pin  314  is provided in the support member  324  to prevent its rotation. Because the pin  314  engages a long hole provided in the bracket  322 , the support member  324  does not rotate even if it moves up and down.  
         [0105]    A base seat  317  is screwed to a push-down board  303 , with the bottom in contact with the top of the support member  316 . The push-down board  303  is freely rotatively supported by a pin  319  and rotates counterclockwise in the FIG. 13 by a force pressing the base seat  317  upward (arrow G), thereby transmitting a push-down force (arrow F) to a bearing  304  which is provided on the other end.  
         [0106]    Specifically, the push-down board  303  pushes down the T-shaped key  14   c  ( 14   d ) via the above-described mechanism in the next 90° rotation of the disc  310 , whereby the cover  203  of the pod  200  may be secured to the door  13 .  
         [0107]    The second embodiment enables one driving force to cause rotation of the T-shaped key  14   c  ( 14   d ) and a pull-in operation of the T-shaped key  14   c  ( 14   d ) to secure the cover  203  to the door  13 . In addition, the apparatus of the second embodiment is also provided with an eccentric transmission mechanism which allows deviation of the base plate  13 A and the position adjusting plate  13 B.  
         [0108]    (Third Embodiment)  
         [0109]    [0109]FIG. 17 shows a holding mechanism of the pod cover removing-installing apparatus according to a third embodiment.  
         [0110]    A holding mechanism  440  has a securing plate  441  provided in a base plate frame (not shown), a base plate  445  provided on the securing plate  441 , a main body  443  connected to the base plate  445  through an O-ring  442  and having a nozzle connected to a vacuum pressure source  451 , an absorption pad  444  provided in the main body  443  and having a seat  444   a  to attach to the position adjusting plate  13 B.  
         [0111]    In this embodiment, a space  446  is formed between the absorption pad  444  and the base plate  445 . The base plate  445  is provided with a nozzle  447  to connect the space  446  to an air pressure source  452 .  
         [0112]    A vacuum pressure source  451  is connected to the nozzle of the main body  443  through solenoid valves SV 1  and SV 2 . The air pressure source  452  is connected to the nozzle  447  through a solenoid valve SV 3 .  
         [0113]    The NC port of the solenoid valve SV 1  spacially communicates with the vacuum pressure source  451 , the NO port with the atmosphere, and the C port with the C port of the solenoid valve SV 2 . The NC port of the solenoid valve SV 2  spacially communicates with the nozzle  443 , and the NO port with NC port of the solenoid valve SV 3 . The C port of the solenoid valve SV 3  spacially communicates with the air pressure source  452  and the NO port is shut off.  
         [0114]    If the solenoid valves SV 1 , SV 2 , and SV 3  are on the NC port side as shown in FIG. 17, with the vacuum pressure source  451  being evacuated and high pressure air being supplied from the air pressure source  452 , the seat  444   a  of the adsorption pad  444  is pushed to the position adjusting plate  13 B side by the pressure of the space  446  and the pressure of the space  448  inside the seat part  444   a  becomes negative, thereby accelerating the adherence of the adsorption pad  444 .  
         [0115]    On the other hand, if the solenoid valve SV 1  is switched to the NO port side to open the space  448  to the atmosphere, then the solenoid valves SV 2 , SV 3  are switched to the NO port side to open the space  446  to the atmosphere, the solenoid valve SV 1  is switched to the NC port side, and the space  446  is adsorbed to accelerate release of the adsorption pad  444 .  
         [0116]    The third embodiment thus accelerates the adherence and release operations of the position adjusting plate  13 B. In addition, because the seat part  444   a  separates from the position adjusting plate  13 B during the release operation, the position adjusting plate  13 B can move smoothly.  
         [0117]    (Fourth Embodiment)  
         [0118]    [0118]FIG. 18 shows a positioning member of the pod cover removing-installing apparatus according to a fourth embodiment.  
         [0119]    [0119]FIG. 18( c ) shows a conventional system. In this system, if the deviation of the positioning pin  14   a  and the pin hole  204   a  becomes larger than δ0=1-1.5 mm, the positioning pin  14   a  may not smoothly enter the pin hole  204   a  depending on a taper  204   t  of the pin hole  204   a  on the pod  200  side.  
         [0120]    A positioning member  500  of the fourth embodiment is provided with an outer casing  501  and an inner casing  502 . The outer casing  501  is a cylinder having a taper  501   a  formed on the tip, a brim  501   b  formed on the outside, a step  501   c  formed inside, a thread part  501   d  formed in the back of the brim  501   b,  and the like, and is secured to the positioning plate  13 B using the brim  501   b.    
         [0121]    The inner casing  502  is a cylinder inserted into the outer casing  501  and has a taper  502   a  having the same angle as the taper  501   a  of the outer casing  501 , and a brim  502   b  formed on the outside of the end, wherein the brim  502   b  engages the step  501   c  to regulate the protrusion to a prescribed length.  
         [0122]    A spring  503  inserted in the inner casing  502  pushes the inner casing  502  in the protrusion direction. A box nut  504  thrust in a thread  501   d  of the outer casing  501  secures the outer casing  501  to the position adjusting plate  13 B and regulates the location of the end of the spring  503 .  
         [0123]    As shown in FIG. 18( a ), because the outer casing  501  and the inner casing  502  are provided with a taper  501   a  or  502   a  having the same angle which is more acute than the conventional angle and a length longer than a conventional one, these are smoothly linked even if the deviation is in the range of δ1=3.0-3.5 mm.  
         [0124]    As shown in FIG. 18( b ), because the inner casing  502  escapes resisting the pushing force of the spring  503  after the completion of linking, the depth of the pin hole  204   a  may be the same depth (L=11 mm) as the pin hole of the conventional pod  200 .  
         [0125]    (Fifth Embodiment)  
         [0126]    [0126]FIG. 19 shows a positioning member for the table of the pod cover removing-installing apparatus according to a fifth embodiment.  
         [0127]    The positioning pins  15   a - 15   c  of the table  15  (see the table  105  of FIG. 21) are arranged as shown in FIG. 19( b ). For this reason, when the table  15  moves in the direction of the arrow M, a force pushing up the pod  200  in the direction of the arrow N (N 1 ) is generated in the V-shaped grooves  205   a,    205   c.  However, no excessive force is produced by the V-shaped groove  205   c  which is parallel to the moving direction.  
         [0128]    As a result, a rotation force around the positioning pin  15   c  in the direction of the arrow P (P 1 ) is created in the pod  200  as shown in FIG. 19( d ). Because of this, the top end of the pod  200  may be separated from the partition board  11 , resulting in problems such as defective sealing.  
         [0129]    In the fifth embodiment, because the vertical fixed side  605   a - 1  ( 605   b - 1 ,  605   c - 1 ) provided in the V-shaped groove  605   a  ( 605   b,    605   c ) formed on the bottom surface of the pod  600  enables the pod  600  to come into contact with the vertical fixed side  15   a - 1  ( 15   b - 1 ,  15   c - 1 ) of the positioning pin  15   a  ( 15   b,    15   c ) (a bonding posture corrective means), no force pushing the pod  600  upward is created even if the container is pushed in the horizontal direction.  
         [0130]    (Sixth Embodiment)  
         [0131]    [0131]FIG. 20 shows a positioning member of the pod cover removing-installing apparatus according to a sixth embodiment.  
         [0132]    The fifth embodiment cannot be applied to a pod  200  which has already been used. Modification of the types and the like is necessary to change such a pod. For this reason, the sixth embodiment is provided with a binding posture corrective mechanism  700  which corrects the linking position of the pod  200 .  
         [0133]    The binding posture corrective mechanism  700  is provided with a rotor  701  such as a bearing provided on the top and side of the door frame  16  connected to the cover frame  207  of the pod  200  and maintaining contact with the cover frame  207 , a moving board  702  rotatively supporting the rotor  701  on the left end thereof and rotatively supported by the axis  702   a  at the upper right end, a linking member  705  which links the moving board  702  with a fixed board  703  so that the rotor  701  always presses the cover frame  207  with a spring  704  between them and regulates the counterclockwise rotation (arrow Q) of the moving board  702 , a regulating member  706  provided on the fixed board  703  to regulate the clockwise rotation (arrow R) of the moving board  702 , and the like.  
         [0134]    The rotor  701  can not only freely move in the moving direction (arrow M) on the table  15  by its rotation, but can also freely move in the right angle direction of the arrow M by the rotation of the moving board  702 . The rotor  701  is arranged so that it always presses the pod  200  by a spring  704 . In addition, the movable range for the rotor  701  is limited via a movable board  702  to the minimum push-out position of the linking member  705  and the maximum push-out position of the regulating member  706 .  
         [0135]    Therefore, the top and the side of the pod  200  can be pressed in the linked position so that the pod  200  is held in a normal posture ready to be linked.  
         [0136]    (Modification)  
         [0137]    The present invention is not limited to the above-described embodiments and can be varied or modified in various ways. Such variations and modifications are within the scope of equivalency of the present invention.  
         [0138]    For example, although the cover securing means was described in FIG. 7 using a stretch member  63  by way of example, a modified type having a broken part in the positioning pin  14   a  ( 14   b ) to mechanically change the diameter of the positioning pin  14   a  ( 14   b ) can be used for securing the pins in the pin holes.  
         [0139]    Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.