Abstract:
A modular frame assembly for a wafer fabrication system comprising at least one base casting and at least one upstanding pod door opening casting. The at least one base casting and at least one upstanding pod door opening casting are self registering and allow frames for wafer fabrication systems of any normally desired configuration to be produced out or a small number of cast modules. More specifically, in a preferred embodiment, frames configured to mate with one to four commercially available loaders may be readily assembled out of the aluminum castings.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
         [0001]    Not Applicable  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not Applicable  
         BACKGROUND OF THE INVENTION  
         [0003]    The present invention relates to wafer fabrication systems used in the manufacture of integrated circuit devices and more specifically to a modular and configurable front end, buffer or frame employed within such systems.  
           [0004]    Wafer fabrication systems are known that include a frame and a number of loaders or pod door openers (PDOs) within the system that are used for loading and unloading wafers for processing. A wafer fabrication system typically includes an input port for receiving wafers via a wafer cassette that may be mounted within a loader, a transport mechanism or robot for manipulating and moving a wafer to a processing station and a processing station for performing a desired fabrication process such as ion implantation, photolithography and metrology. Known wafer fabrication systems include a frame that is assembled based upon the specific number of loaders to be employed within the particular wafer processing system. The frame typically comprises a skeleton that includes steel frame members or components that are welded together to form the frame assembly.  
           [0005]    Wafer fabrication system frames produced in the above manner have a number of drawbacks. First, large numbers of component parts need to be inventoried or produced to accommodate the different frame sizes. Second, welding of the frames is a time consuming labor intensive process and is inherently prone to large machine tolerances. Third, the lead time to produce a wafer fabrication system frame that employs numerous components is fairly great given the labor involved. Fourth, storage and transportion of welded frames is costly due to their large volumes. Additionally, there may be lead times associated with the fabrication of specific components of the frame if it is not designed to inventory all possible components.  
           [0006]    For the above reason it would be desirable to be able to construct a frame for the front end of a wafer fabrication system that employs a small number of components. Such a frame should accommodate commercially available loaders, provide accurate registration among the component parts of the frame, be cost efficient to manufacture, and be assembled to accomodate one or more loaders.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    In accordance with the invention a modular frame for a configurable front end for a wafer fabrication system is disclosed. The configurable frame includes one or more predetermined base castings and one or more predetermined upstanding pod door opening (PDO) castings adapted to mate with corresponding base castings. Via use of the base and PDO castings, frames may be readily assembled from standard components without necessitating weldments or custom manufacture of components to accommodate a desired a number of loaders.  
           [0008]    More specifically, in a preferred embodiment a modular frame is constructed from one or more self-referencing aluminum base castings and one or more upright self-referencing aluminum PDO castings.  
           [0009]    The modular nature of the castings permit multiple configurations of wafer fabrication system frames to be constructed out of a limited number of base and PDO castings.  
           [0010]    Other features, aspects and advantages of the invention will be apparent to those of ordinary skill in the art from the detailed description of the invention that follows. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0011]    The invention will be more fully understood by reference to the following detailed description of the invention taken in conjunction with the Drawing of which:  
         [0012]    [0012]FIG. 1 is a perspective view of a modular frame assembly for a wafer fabrication system in accordance with the present invention casting;  
         [0013]    [0013]FIG. 2 a  is a perspective view of an extended single width base casting for use in the fabrication of a frame for a wafer fabrication system;  
         [0014]    [0014]FIG. 2 b  is a perspective view of an extended double width base casting for use in the fabrication of a frame for a wafer fabrication system;  
         [0015]    [0015]FIG. 2 c  is a perspective view of a double width base casting for use in the fabrication of a frame for a wafer fabrication system;  
         [0016]    [0016]FIG. 2 d  is a cross-sectional view through a leveling foot depicting the mounting of the leveling foot to a base casting;  
         [0017]    [0017]FIG. 3 a  is a perspective view of an single width pod door opening casting for use in the fabrication of a frame for a wafer fabrication system;  
         [0018]    [0018]FIG. 3 b  is a perspective view of a double width pod door opening casting for use in the fabrication of a frame for a wafer fabrication system;  
         [0019]    [0019]FIG. 4 is a perspective view of a frame assembly for a wafer fabrication system configured and adapted to mate with a single loader;  
         [0020]    [0020]FIG. 5 is a perspective view of a frame assembly for a wafer fabrication system configured and adapted to mate with two loaders; and  
         [0021]    [0021]FIG. 6 is a perspective view of a frame assembly for a wafer fabrication system configured and adapted to mate with four loaders. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    In accordance with the present invention, a modular frame for a wafer fabrication system that can accommodate one or more loaders and wafer handling equipment is disclosed. The frame includes one or more base castings and a corresponding number of upstanding pod door opening (PDO) castings mounted to the respective base castings. Using a limited number of base castings and pod door opening castings a frame is assembled to accommodate any wafer fabrication system that is typically desired. The pod door opening castings are self registering with respect to the base castings to allow rapid assembly of a frame that is required to meet the particular needs of a customer.  
         [0023]    Referring to FIG. 1, an exemplary modular frame  10  for a wafer fabrication system is shown. The frame  10  includes a plurality of base castings  12  and a plurality of PDO castings  14 . The base castings  12  are fastened to adjacent base castings to form a base assembly. An upstanding PDO casting  14  is mounted to each of the base castings  12  and each PDO casting is pinned and fastened to adjacent PDO castings. The respective upstanding PDO castings  14  define a plane generally perpendicular to the plane of the respective base casting  12 . Each PDO casting  14  is configured and adapted to mate with either one or loaders. The number of loaders that can be accommodated by a given frame is defined by the number and type of castings employed.  
         [0024]    [0024]FIGS. 2 a  through  2   c  depict exemplary base castings  12  that may be employed as modules in the fabrication of the presently disclosed frames. More specifically, FIG. 2 a  depicts an extended single width base casting  12   a  that is sized and configured to accommodate a single width PDO casting. FIG. 2 b  depicts an extended double width base casting  12   b  that is sized to accommodate a double width PDO casting. FIG. 2 c  depicts a double width base casting  12   c  that is sized to accommodate a double width PDO casting.  
         [0025]    Each of the base castings  12  has a generally similar configuration. More specifically, the base castings,  12   a ,  12   b ,  12   c  each include side members  16 , a front member  18  and a rear member  20  integrally formed with the respective casting. Additionally, the base castings  12   a ,  12   b ,  12   c  each include longitudinal support members  22  and transverse slat members  24 . Furthermore, the base castings  12   a ,  12   b ,  12   c  each include four pedestal sections  26  adjacent the front member  18  and rear member  20  of the respective base casting  12 . The pedestal sections  26  are spaced a predetermined distance from the sides  16  of the respective casting  12  and provide a supporting structure for casters mounted on the underside of the casting. The underside of the pedestal section (not shown) is generally flat. Casters having a generally rectangular caster mounting plate may be bolted to the underside of the respective base castings  12  by screwing bolts into corresponding threaded openings  28  in the respective pedestal sections  26 .  
         [0026]    The base castings  12   a ,  12   b ,  12   c  each include openings  30  sized to receive alignment dowel pins. The dowel pins are inserted into the respective openings  30  and extend into corresponding openings in a corresponding PDO casting when the PDO casting is disposed in a mounting position with regard to the base casting as is subsequently discussed. The base castings  12   a ,  12   b ,  12   c  also include PDO casting mounting holes  32 . The PDO mounting holes  32  are counterbored through holes that receive a mounting bolt from the underside of the respective castings. The mounting bolts extend through the respective PDO mounting holes  32  and engage cooperate threaded holes (not shown) within respective PDO castings.  
         [0027]    Furthermore, the base castings  12  include leveling foot threaded through holes  34  in the corners of the respective base castings  12 . Referring to FIG. 2 d , leveling feet  48  have a foot portion  50  and a threaded bolt portion  52 . To mount a leveling foot  48  to a base casting  12  a first nut  54  is threaded onto the threaded bolt portion  52  of the leveling foot  48 . The bolt portion  52  may then be threaded through a respective leveling foot threaded through hole  34  and a second nut  56  may optionally be screwed onto the threaded bolt portion  52  on the topside of the respective base casting  12  to capture the base casting  12  between the first and second nuts  54  and  56  (FIG. 2 d ). The first nut  54  may be tightened against the underside of the base casting  12  to secure the leveling foot  52  in position, even if the second nut  56  is not used.  
         [0028]    The base castings  12   a ,  12   b ,  12   c  also include holes  36  in the sides of the sides  16  of the castings  12  to allow for the fastening of one base casting  12  to an adjacent base casting  12 . The holes  36  may comprise through holes for bolts or alternatively, one casting may have through holes  36  for a bolt and the adjacent casting may have a threaded hole sized to receive a bolt that passes through the through holes  36  of the adjacent casting.  
         [0029]    The base castings  12   a ,  12   b  and  12   c  further include threaded holes  38  in the front member  18  of the respective base casting  12  that are used for the mounting of the PDO castings  14  to the corresponding base castings  12 . Additionally, the base castings  12  include clearance holes  40  that receive the ends of bolts that are employed to mount loaders to the respective PDO castings (FIG. 2 c ).  
         [0030]    The base castings  12  also include threaded mounting holes  42  in the pedestal sections  26  of the respective base castings  12  that are employed for the attachment of a structural panel (not shown) to the casting and threaded mounting holes  44  in the rear section  20  of the respective castings  12  that are employed for the attachment of a rear structural panel (not shown) to the frame.  
         [0031]    [0031]FIGS. 3 a  and  3   b  depict a single PDO casting  14   a  and a double PDO casting  14   b  respectively. The single and double PDO castings  14   a  and  14   b  respectively, are of a generally similar structure noting that the single PDO casting  14   a  is configured and adapted to mate with a single loader (not shown) and the double PDO casting  14   b  is configured and adapted to mate with two loaders (not shown). The PDO castings  14   a ,  14   b  include left and right side members  60   a  and  60   b  respectively, top and bottom members  62  and  64  respectively, upper mounting rails  66  and lower mounting rails  68   a  and  68   b . The upper mounting rails  66  provide a mounting structure for a mid-partition table (not shown) that is typically mounted behind the respective upper mounting rail  66 . The lower mounting rails  68   a ,  68   b  provide a mounting structure that accurately registers a vertically mounted linear track (not shown) or a robot (not shown) in a trackless system to a loader. More specifically, the lower mounting rails  68   a ,  68   b  may include pins that register with openings in the vertically mounted linear track or the robot to accurately position the track or robot to achieve precise alignment with the associated loader. Threaded openings in the lower mounting rails  68   a ,  68   b  are provided to allow for fastening of the vertically mounted linear track or the robot to the respective lower mounting rails. Alternatively, threaded holes may be provided in the structure of the vertically mounted linear track or the robot such devices may be fastened to the lower mounting rails via fasteners that extend through through-holes provided in the lower mounting rails  68   a ,  68   b . Additionally, threaded holes and pin holes are provided in the sides of the PDO castings  14   a ,  14   b  for fastening adjacent PDO castings to each other. Finally, structural end panels (not shown) are mounted to the PDO castings using the exposed holes on the side of the PDO casting assembly.  
         [0032]    The double width PDO casting  14   b  (FIG. 3 b ) further includes a vertical dividing member  70  that separates the left side pod door opening area from the right side pod door opening area. Counterbored through holes  72  are provided in the bottom member  64  of the PDO castings  14   a ,  14   b . The counterbored through holes  72  in the single width PDO casting  14   a  coaxially align with corresponding openings  38  in the front member  18  of the extended single width base casting (FIG. 2 a ) when the single width PDO casting  14   a  is disposed in a mounting position with respect to the extended single width base casting  12   a . It is noted that the extended single width base casting  12   a  is wider than the width of the single width PDO casting by approximately  12  inches in the illustrative embodiment to allow an electronic equipment rack to be mounted at one end of the casting. The single width PDO casting  14   a  may be mounted to the extended single width base casting  12   a  left justified using a first pair of threaded openings  38  in the front member  18  of the base casting  12   a  to allow for the mounting of an electronic equipment rack on the right side of the casting. Alternatively, the single width PDO casting  14   a  may be mounted to the extended single width base casting  12   a  right justified using a second pair of threaded openings  38  in the front member  18  of the base casting  12   a  to allow for the mounting of an electronic equipment rack on the left side of the casting.  
         [0033]    Similarly the counterbored through holes  72  in the double width PDO casting  14   b  (FIG. 3 b ) coaxially align with corresponding openings  38  in the front member  18  of the extended double width base casting (FIG. 2 b ) when the double width PDO casting  14   b  (FIG. 3 b ) is disposed in a mounting position with respect to the extended double width base casting  12   b . As in the case of the extended single width base casting  12   a , the extended double width base casting  12   b  is wider than the width of the double width PDO casting by approximately  12  inches in the illustrative embodiment to allow an electronic equipment rack to be mounted at one end of the casting. The double width PDO casting  14   b  (FIG. 3 b ) may be mounted to the extended double width base casting  12   b  (FIG. 2 b ) left justified using a first pair of threaded openings  38  in the front member  18  of the base casting  12   b  to allow for the mounting of an electronic equipment rack on the right side of the casting. Alternatively, the double width PDO casting  14   b  may be mounted to the extended double width base casting  12   b  right justified using a second pair of threaded openings  38  in the front member  18  of the base casting  12   b  to allow for the mounting of an electronic equipment rack on the left side of the casting.  
         [0034]    Additionally, the double width PDO casting  14   b  may be mounted to the double width base casting  12   c . When the double width PDO casting  14   b  is disposed in a mounting position with respect to the double width base casting  12   c , the counterbored through holes  72  in the double width PDO casting  14   b  (FIG. 3 b ) coaxially align with corresponding threaded openings  38  in the front member  18  of the double width base casting (FIG. 2 c ). The base castings  12   a ,  12   b ,  12   c  and the PDO castings  14   a ,  14   b  may be fabricated as aluminum castings or castings of any other suitable material. Utilizing a limited number of castings, frame assemblies may be fabricated to accommodate any desired number of loaders.  
         [0035]    The PDO castings  14  include one or more wire channels  76  comprising elongated openings that extend vertically through the top member  62  of the respective PDO casting  14  (FIGS. 3 a ,  3   b ). The wire channels  76  provide passageways within the respective PDO casting  14  to facilitate the routing of system wiring that may be required.  
         [0036]    [0036]FIG. 4 depicts a frame assembly for a single loader that comprises a single width PDO casting  14   a  and an extended single width base casting  12   a . FIG. 5 depicts a frame assembly configured and adapted to receive two loaders. The frame assembly comprises one double width PDO casting  14   b  and one extended double width base casting  12   b . FIG. 1, as previously noted, depicts a frame assembly configured and adapted to receive three loaders. The frame assembly depicted in FIG. 1 comprises an extended single width base casting  12   a  (FIG. 2 a ), a double width base casting  12   c  (FIG. 2 c ), a single width PDO casting  14   a  (FIG. 3 a ) and a double width PDO casting  14   b  (FIG. 3 b ). FIG. 6 depicts a frame assembly configured and adapted to receive four pod units. The frame assembly depicted in FIG. 6 comprises an extended double width base casting  12   b  (FIG. 2 b ), a double width base casting  12   c  (FIG. 2 c ) and two double width PDO castings  14   b  (FIG. 3 b ).  
         [0037]    It will be appreciated by those of ordinary skill in the art that modifications to and variations of the above-described frame assemblies for a wafer fabrication system may be made without departing from the inventive concepts disclosed herein. Accordingly, the invention should not be viewed as limited except as by the scope and spirit of the appended claims.