Patent Document

BACKGROUND OF THE INVENTION  
         [0001]    a) Field of the Invention  
           [0002]    The invention is directed to a loading and unloading station for semiconductor processing installations with at least one closeable charging opening through which wafer-shaped or disk-shaped objects which are accommodated in a transporting container can be loaded, unloaded and reloaded after removing a closure, wherein the transporting container is provided with a container cover which extends substantially at right angles to the loading plane.  
           [0003]    b) Description of the Related Art  
           [0004]    For the purpose of charging semiconductor processing installations, it is known to use so-called SMIF boxes as magazine containers with a relatively small enclosed volume in which wafer magazines can be stored and transported. The box can be placed on an opening mechanism in an enclosure or housing which encloses one or more work stations so as to keep them free of dust. The box and opening mechanism have closing elements which are adapted to one another and which can be opened simultaneously one above the other so that dust particles resting on the outside of the closing elements can be enclosed therebetween when the wafer magazines are lowered into the housing together with the two closing elements. The box itself encloses the opening formed in the housing.  
           [0005]    A loading and unloading device according to the German Patent 43 26 309 C1, for example, or a device having another operating sequence serves to remove the magazines from the transporting containers and place them in the processing installation. After the semiconductor wafers are processed, the magazines are transported back in the transporting containers.  
           [0006]    The technique of SMIF boxes is especially suited for semiconductor wafers with smaller diameters, as is conventional. In view of the material characteristics of the semiconductor wafers, these SMIF boxes and the wafer magazines used with them are becoming increasingly unsuitable as transporting containers as the diameter of semiconductor wafers increases. Transporting containers which take over the function of magazines at the same time are already known for semiconductor wafers of this type. Loading, unloading and reloading of the semiconductor wafers is effected individually in a plane parallel to the surface of the semiconductor wafers, wherein the transporting container can be closed by a container cover extending substantially at right angles to the loading and unloading plane. Accordingly, in contrast to the SMIF box, the container cover is removed and inserted laterally rather than in a downward direction.  
           [0007]    Since the transporting containers are enclosed by a space with low requirements as regards cleanness and since there are no magazines which can be loaded and unloaded such as those used in the SMIF technique, the charging of semiconductor processing installations proceeding from these transporting containers and the transporting back from such installations into the transporting containers presents problems. Moreover, the problem is exacerbated in that optional loading and unloading into and out of a greater number of transporting containers must be ensured under certain circumstances and the containers themselves must be supplied and removed by operating personnel under favorably ergonomic conditions.  
           [0008]    An arrangement for storing, transporting and inserting substrates is known from EP 542 793 B1. In this arrangement, a cassette with a lateral closing cap is arranged opposite a loading slot. The cassettes are brought into the loading position one after the other by a lifting plate which can hold a packet of stacked cassettes. When this position is reached, the closing cap is swiveled open at one edge and the substrate wafer is inserted into the clean room by a drawer which can travel out of the cassette. An air flow exiting from the loading slot prevents particles from penetrating into the clean room in that it passes through an open gap between a protruding seal and the cassette.  
         OBJECT AND SUMMARY OF THE INVENTION  
         [0009]    The primary object of the present invention is to ensure a charging of semiconductor processing installations proceeding from transporting containers under clean room conditions, these transporting containers themselves serving as magazines for disk-shaped objects and being open laterally. It should also be possible, optionally, to load and unload a greater quantity of such transporting containers, wherein the exchange of transporting containers must be effected under favorable ergonomic conditions.  
           [0010]    In a loading and unloading station for semiconductor processing installations with a closable charging opening through which disk-shaped objects, which are accommodated in a transporting container, can be loaded, unloaded and reloaded after removing a closure, wherein the transporting container is provided with a container cover which substantially extends so as to be directed vertically to the loading and unloading plane, the object according to the present invention is met in that the transporting container for loading, unloading and reloading of disk-shaped objects is coupled in a stationary manner by the container cover with the closure by means of an adhering engagement and a simultaneous opening of the charging opening and transporting container is effected in that the container cover and the closure are moved down jointly into the semiconductor processing installation. The loading and unloading is carried out in that a manipulating device which is arranged in the semiconductor processing installation engages through the charging opening into the transporting container.  
           [0011]    For the purpose of coupling with the closure, the transporting container is deposited on a horizontally adjustable first platform which is provided with means for aligning and securing the transporting container.  
           [0012]    The platform is adjustable between at least two planes which are located one above the other, one of which planes serves for charging with a transporting container at an ergonomic height, while the other serves for loading and unloading the semiconductor processing installation.  
           [0013]    In an advantageous manner, a suitable number of additional, horizontally adjustable platforms which are provided with means for aligning and securing the transporting container can be provided for holding at least one additional transporting container. At least one of the platforms serves alternately to couple a transporting container with the closure, while the others remain free for the exchange of transporting containers.  
           [0014]    A storage is also advantageously provided for the exchange of transporting containers, in which storage a gripper has optional access to storage compartments or shelves which are arranged one above the other and a loading opening with a transporting container holder is provided for manual charging with transporting containers. A space corresponding to the dimensions of a transporting container is left open adjacent to the storage shelves for transferring the transporting containers between the transporting container holder, storage shelves, and the platform. The transporting container holder should be able to travel out through the loading opening for the purpose of charging.  
           [0015]    Further, the closure advantageously has vacuum suction devices for producing the adhering engagement with the container cover and is provided with elements for aligning relative to the container cover which can take effect before the adhering engagement is produced.  
           [0016]    In order to open the transporting container, keys for actuating the locking elements in the container cover project out of the closure, matching keyholes for these keys being provided in the container cover, by which the closure and container cover are secured above and beyond the adhering engagement. The aligning elements and the keys can be held in a springing manner vertically to the loading and unloading plane in order to coml)ensate for differences between the approach of the closure and the container cover.  
           [0017]    Also, the charging opening is advantageously worked into a plate or shield which is adjustable, relative to the manipulating device, jointly with (he coupled transporting container for loading and unloading the disk-shaped objects in a direction vertical to the loading and unloading plane depending on the indexed positions. Accordingly, it is possible to carry out the movement between the different planes as well as the indexing movements by means of an individual elevator.  
           [0018]    However, it is also possible to construct the manipulating device for loading and unloading the disk-shaped objects in a direction vertical to the loading and unloading plane depending upon the indexed positions.  
           [0019]    By means of the described solution according to the invention, transporting containers of the type described above can be used without negatively affecting the clean room conditions within the semiconductor processing installation to be charged. Semiconductor wafers with dimensions of 300 mm can be manipulated easily. Dust particles located on the container cover during the coupling with the closure are reliably enclosed between the surfaces which are connected in an adhering engagement.  
           [0020]    The invention will be explained more fully in the following with reference to the schematic drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]    In the drawings:  
         [0022]    [0022]FIG. 1 shows a basic side view of a loading and unloading station with a displaceable shield;  
         [0023]    [0023]FIG. 2 shows a top view of the loading and unloading station;  
         [0024]    [0024]FIG. 3 shows a front view of the loading and unloading station;  
         [0025]    [0025]FIG. 4 is a perspective view of a loading and unloading station with a transporting container in the coupled and opened state;  
         [0026]    [0026]FIG. 5 is a view in partial section of a first device for opening and closing a closure, shown in the closed state;  
         [0027]    [0027]FIG. 6 shows a side view of the device according to FIG. 5 in the closed state;  
         [0028]    [0028]FIG. 7 shows a perspective view of a loading and unloading station with an additional platform and additional transporting container;  
         [0029]    [0029]FIG. 8 shows a side view of the loading and unloading station according to FIG. 7;  
         [0030]    [0030]FIG. 9 shows a side view of a storage for transporting containers;  
         [0031]    [0031]FIG. 10 shows the storage in a perspective view and partially opened;  
         [0032]    [0032]FIG. 11 shows a top view of an opened storage;  
         [0033]    [0033]FIG. 12 shows a closure and a container cover;  
         [0034]    [0034]FIG. 13 shows the preorientated coupling of the closure and the container cover;  
         [0035]    [0035]FIG. 14 shows a first variant of a clipped and partially cut-away transporting container;  
         [0036]    [0036]FIG. 15 shows a section A-A through the transporting container according to FIG. 14;  
         [0037]    [0037]FIG. 16 shows a second variant of a clipped and partially cut-away transporting container;  
         [0038]    [0038]FIG. 17 shows a section B-B through the transporting container according to FIG. 16;  
         [0039]    [0039]FIG. 18 shows a front view of a portion of a loading and unloading station with a second device for opening and closing a closure; and  
         [0040]    [0040]FIG. 19 shows a top view of the device according to FIG. 18. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0041]    In FIGS.  1  to  3 , a frame  1  which is connected in a stationary manner with a wall element  2  by two angled frame elements  3 ,  4  carries an elevator  5 .  
         [0042]    Platforms  7  which are adjustable horizontally in the direction of the wall element  2  in a guide  8  which is secured at the elevator  5  serve as holding means for transporting containers  6  which can be shaped and outfitted in different ways within certain limits. The platforms  7 , whose quantity is not restricted to that shown herein, are movable by means of the elevator  5  between at least two planes  9  and  10  which are situated one above the other. While plane  9  is situated at an ergonomically favorable height for charging the platforms  7 , the semiconductor processing installation is loaded and unloaded in plane  10 . For this purpose, a charging opening  13  which can be closed by means of a closure  12  is worked into a shield  11 . The shield  11  is adjustable in a direction vertical to the plane  10  along the wall  2  so as to be guided by guide means  14  and performs a sealing function relative to the opening in the wall element  2 . A transporting container  6  is coupled to the closure  12  by its container cover  15  in an adhering engagement by means of the horizontal displacement of one of the platforms  7  in the direction of the wall element  2 . For this purpose, suction elements  16  are incorporated in the closure  12 , a hose connection, not shown, leading from the latter to a vacuum source.  
         [0043]    The container cover  15  which is slid into and locked in the transporting container  6  is surrounded by a seal  17  ensuring a seal relative to the surrounding wall. Unlocking is effected after the adhering engagement is produced, and the closure  12  can be moved down together with the container cover  15  into the semiconductor processing installation in the manner indicated by an angled arrow.  
         [0044]    Every transporting container  16  has shelves for receiving disk-shaped objects  19 , which shelves are situated one above the other and are formed by projections  18 . In order to load and unload the latter through the charging opening  13  in plane  10 , it is necessary in the construction shown in FIG. 1 to adjust the vertical position of the transporting container  6  in a suitable manner. For this purpose, the transporting container  6  is additionally sealed externally relative to the shield  11  by a seal  20 , this shield  11  being carried along in turn by a vertical indexing movement which is likewise executed by means of the elevator  5 . The clean room conditions within the semiconductor processing installation remain unimpaired as a result of the sealing finction of the shield  11 .  
         [0045]    For the purpose of indexing, an index sensor  21  detects the projections  18  and the disk-shaped objects  19  during the vertical adjustment of the transporting container  6 .  
         [0046]    Loading and unloading is effected in plane  10  by means of a manipulating device  22  arranged in the clean room region of the semiconductor processing installation by engaging through the charging opening  13 .  
         [0047]    In the loading and unloading station shown in FIG. 4, a device which is shown in more detail in FIG. 5 is used to open and close a closure  23 . A transporting container  24  which is already opened is deposited on a platform  26  which is supported by a stationary plate  25  and is displaceable horizontally in the direction indicated by the arrow, this transporting container  24  communicating with a charging opening  27  in a wall element  28 . The closure  23  is secured to an arm  29 , which is adjustable vertically and relative to the wall element  28 , and supports a container cover  30  which is coupled by means of an adhering engagement. Driving and controlling elements for the loading and unloading station are accommodated in a housing  31 .  
         [0048]    According to FIG. 5, lifting cylinders  32  and  33  are provided for vertical adjustment and for adjusting the arm  29  relative to the wall element  28 , wherein the lifting cylinder  32  which is secured to a support plate  34  is swivelable together with the support plate  34  about an axis X-X until reaching a stop  35  by means of the action of the lifting cylinder  33 .  
         [0049]    In FIG. 7, in contrast to the embodiment form according to FIG. 4 which provides for holding only one transporting container  24 , supports  36  which are secured to the plate  25  carry an additional stationary plate  37  to which is fastened a second platform  38  which is displaceable horizontally in the direction of the arrow. Another transporting container which is closed by a transporting container cover  39  is designated by  40 .  
         [0050]    The two platforms  26 ,  37  are adjustable vertically via a supporting arm  42  which is connected with the plate  25  and can be raised and lowered by a drive  41 . While one of the platforms  26 ,  37  serves to couple a transporting container  24  or  38  to the closure  23 , the other remains available for the exchange of transporting containers.  
         [0051]    Of course, the vertical adjustability shown in FIGS. 7 and 8 is also readily applicable by a person skilled in the art to the construction shown in FIG. 4 in that only one transporting container is adjustable between two planes. Similarly, the quantity of transporting containers which can be held can also be increased in accordance with the respective requirements.  
         [0052]    A storage can be used for changing transporting containers in loading and unloading devices according to FIGS. 4, 7 and  8  as is described more fully with reference to FIGS.  9  to  11 .  
         [0053]    The loading and unloading device is integrated in a wall  43  of a housing  44  provided with storage shelves  45  which are arranged one above the other and serve to hold transporting containers  46 . In the present embodiment example, the storage is so constructed that the storage shelves  45  are arranged above the platforms of the loading and unloading device regardless of the loading and unloading direction. For the purpose of optional access to the transporting containers  46  in the storage shelves  45 , it is essential that a space  47  corresponding to the dimensions of the transporting containers  46  be left open between the storage shelves  45  and a wall of the housing  44  other than wall  43 . The wall at which the space is left open is determined by the available space for storage.  
         [0054]    In the present construction, the free space is located at a wall  48  adjoining the wall  43  with the loading and unloading device so that a storage of small depth is formed. A lockable loading opening  50  which, in addition to a transporting container holder  52  which can be moved out on guides  51 , serves for manually charging the storage with the transporting containers  46  is worked into the wall  49  located opposite wall  43  at an ergonomic height.  
         [0055]    According to FIG. 11, a gripper  53  which is movable vertically and horizontally for transferring the transporting containers  46  is secured to a horizontal drive  55  by an extension arm  54 . The horizontal drive  55  is in turn connected with an elevator  56 .  
         [0056]    In the cover region, the transporting containers  46  have a handle  57  to be grasped automatically by the gripper  53 . Sufficient space is left above each transporting container  46  for the extension arm  54  to act with the gripper  53  for transferring.  
         [0057]    After a transporting container  46  is grasped, it is transported horizontally from the storage shelf  45  into the open space  47  and is then transported vertically up to a plane which corresponds to the ergonomic height for manually charging the storage or to a plane for charging a platform of the loading and unloading device. When the plane is reached, the transporting container  46  is transferred to the platform or the transporting container holder  52  in the moved in position (FIG. 11 shows the transporting container holder  52  in the moved out position). Displacement in the opposite direction is effected in an analogous manner.  
         [0058]    According to FIGS. 12 and 13, the closure  23  has suction elements  59  emerging from bore holes  58 , aligning elements in the form of pins  60  being arranged in the center thereof. Further, keys  61  with a double-bit for actuating locking elements  62  in the container cover  30  are provided in the closure  23 . An elongated hole  63  and a bore hole  64  which are adapted to the pins  60  are incorporated in the container cover  30 , as are corresponding keyholes  65  for the keys  61 . For the purpose of a preorientated alignment of the container cover  30  relative to the closure  23  during the coupling process, the pins  60  project beyond the suction elements  59  so that the latter first engage in the elongated hole  63  or in the bore hole  64 . Subsequently, the keys  51  penetrate into the keyholes  65 , the suction elements  59  resting on the surface of the container cover  30  by their projecting lips  66 . During the suction process which now takes place, in which the lips  66  move back completely into the bore holes  58  which are constructed with a sufficiently large diameter, the surfaces of the closure  23  and container cover  30  are connected with one another in an adhering engagement and enclose adhering particles therebetween. By rotating the keys  61 , a driver  67  provided in the interior of the container cover  30  is actuated and opens the locking elements  62 . The closure  23  can be moved down into the semiconductor processing installation together with the container cover  30  so as to form a lock or transfer channel.  
         [0059]    Apart from their opening function, the keys  61  exercise another advantageous effect. After the keys  61  which are inserted into the keyholes  65  are turned, the container cover  30  is also held, in the event of a failure of the vacuum in the suction elements, in that the double-bit engages behind the keyholes  65 . The lips  66  of the suction elements  59  which expand again remain in tight contact with the surface of the container cover  30  so that both surfaces can be securely pressed together again immediately when the vacuum is restored. In order to prevent tensions during coupling, the aligning elements and the keys  61  are additionally held in a springing manner inside the closure  23  which is hollow inside.  
         [0060]    Further advantageous steps for the coupling of the transporting container will be seen from FIGS.  14  to  17 . On the one hand, the transporting container is deposited on the platform so as to be aligned. On the other hand, forces act on the transporting container during the opening process, as was explained, e.g., in the description referring to FIGS. 12 and 13, which forces must be compensated for in order to prevent disruption of the loading and unloading process.  
         [0061]    In FIGS. 14 and 15, a transporting container  68  is deposited on a platform  69  which corresponds in terms of function to the platforms shown in the Figures which were already described. The transporting container  68  has shelves  70  in its interior for holding disk-shaped objects. As was already mentioned with respect to the transporting container in FIG. 11, a handle, designated in this instance by  71 , for an automatically operating gripper is arranged in the over region. Aligning elements in the form of grooves  72  and engaging pins  73  which are adapted to one another for the purpose of orientated placement are provided in a three-point formation in the base of the transporting container  68  and in the platform  69 . During the horizontal coupling movement of the transporting container  68 , a springing roller  74  slides at a contact pressut c arm  75 , which is stationary relative to the platform  69 , along a beveled crosspiece  76 , which is secured at the base at a distance therefrom, and fixes the transporting container  68 . Visual orientation pegs  77  may be helpful if the transporting container  6  is to be placed on the platform  69  manually.  
         [0062]    Another way of securing a transporting container on the platform is provided by a solution according to FIGS. 16 and 17. A key  79  which is guided through a bore hole  78  in the platform  69  penetrates through a keyhole  80  during the placement of the transporting container  68 , this keyhole  80  being worked into a plate  81  which is fastened at the base at a distance therefrom, and engages behind the plate  81  after a closing movement.  
         [0063]    Another device for opening and closing a closure is described with reference to FIGS. 18 and 19, by means of which device the loading and unloading device can be decreased in depth. As in FIGS.  1  to  3 , this embodiment example employs a shield, the charging opening being worked into this shield. However, it is also possible to use a stationary charging opening in combination with this device. Although the charging opening is open, a coupled transporting container deposited on a platform is not shown for the sake of simplicity.  
         [0064]    The shield with the charging opening, designated in this instance by  82  and  83 , is supported by a frame  84  via guides  85  and guide slides  86 . A closure  87  for the charging opening  83  is fastened, via an arm  88 , to a rotor axle  89  which is driven by a rotary drive  90 . The rotary drive  90  is screwed to a holding plate  91  which is displaceable in the loading and unloading direction by means of a horizontal guide  92  on a support plate  93  which is connected with the frame  84  in a stationary manner. The displacement is effected by means of a suitable drive  94 , e.g., a pneumatic drive.  
         [0065]    The shield  82  is advantageously designed so as to be reinforced in the region of the charging opening  83  and covers an opening in a wall  95  to which the frame  84  is fastened. The opening, which is not visible, is dimensioned vertically so as to allow a vertical adjustment of the charging opening  83  along the entire opening height. Accordingly, a manipulating device which is arranged in a stationary manner can achieve access through the charging opening in different indexed planes of a coupled transporting container.  
         [0066]    A labyrinth seal  96  performs a sealing function during the adjustment of the shield  82 , one portion of the labyrinth seal  96  being secured so as to adjoin the opening in the wall  95  while the other portion is secured at the adjustable shield  82 .  
         [0067]    A driver  98  for the platform, which driver  98  can be actuated by a pneumatic cylinder  97 , is fastened at the shield  82  for the purpose of coupling the transporting container. After the platform has been moved along with the transporting container into the coupling region, it is grasped by the driver  98 . By means of the lift of the pneumatic cylinder  97 , the transporting container, which is fixed on the platform, is pressed, with its container cover, against the closure  87  which is still in the closing state. The closure  87  and the container cover are connected with one another in an adhering engagement, as has already been described, and the locking elements in the container cover are opened.  
         [0068]    When actuated by the drive  94 , the support plate  3  is displaced together with the elements fastened thereto so that the closure  87 , together with the container cover, is removed from the charging opening  83 . The closure  83  is driven by the motor  90  so as to rotate into a position in which the charging opening is free for loading and unloading the disk-shaped objects. This position corresponds to that shown in FIG. 18.  
         [0069]    While the foregoing description and drawings represent the preferred embodiments of the present invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the true spirit and scope of the present invention.

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