Abstract:
In one aspect, a substrate cleaning system is provided. The substrate cleaning system includes a plurality of cleaning modules; a conveyor for transporting a substrate between the cleaning modules; and a partition assembly that isolates the cleaning modules from the conveyor. Apparatus and methods for isolating CMP cleaning modules from a conveyor are provided, as are numerous other aspects.

Description:
RELATED APPLICATIONS 
       [0001]    The present application claims priority from U.S. patent application Ser. No. 61/640,000, filed Apr. 30, 2012, entitled “METHODS AND APPARATUS FOR ISOLATING A RUNNING BEAM CONVEYOR FROM A SEMICONDUCTOR SUBSTRATE CLEANING ENVIRONMENT” (Attorney Docket No. 16939/L) which is hereby incorporated herein by reference in its entirety for all purposes. 
     
    
     FIELD 
       [0002]    The present invention generally relates to semiconductor substrate cleaning systems, and more particularly is directed to methods and apparatus for isolating a conveyor from the operating environment of a semiconductor substrate cleaning system. 
       BACKGROUND 
       [0003]    Existing chemical mechanical planarization (CMP) systems including pre-CMP substrate cleaning modules may use a running beam conveyor to move substrates from a factory interface to the cleaning modules and to the CMP polisher. Particle contamination of the substrates can interfere with CMP processing and result in undesirable polishing results. Thus, what are needed are methods and apparatus for reducing the possibility of particle contamination of the cleaning environment in which the CMP system is operated. 
       SUMMARY 
       [0004]    In a first aspect, a substrate cleaning assembly is provided. The substrate cleaning assembly includes a plurality of cleaning modules; a conveyor for transporting a substrate between the cleaning modules; and a partition assembly that isolates the cleaning modules from the conveyor. 
         [0005]    In another aspect, a substrate cleaning apparatus is provided. The substrate cleaning apparatus isolates cleaning modules from a substrate conveyor, for example, in a CMP cleaning system. The apparatus includes a support; a rail below the support; and a partition held by the support on the rail, the partition configured to be disposed between a conveyor for transporting a substrate and a plurality of cleaning modules, and to isolate the cleaning modules from the conveyor. 
         [0006]    In yet another aspect, a method of operating a substrate cleaning system is provided. The method involves isolating cleaning modules of a substrate polishing system from a conveyor. The method includes providing a plurality of cleaning modules disposed adjacent to each other; providing a conveyor for transporting a substrate between the cleaning modules; and isolating the cleaning modules from the conveyor by disposing a partition between the conveyor and the cleaning modules. 
         [0007]    Numerous other aspects are provided. Other features and aspects of the present invention will become more fully apparent from the following detailed description, the appended claims and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a schematic block diagram depicting an example CMP cleaning system according to some embodiments of the present invention. 
           [0009]      FIG. 2  is a perspective diagram depicting an example CMP cleaning system according to some embodiments of the present invention. 
           [0010]      FIG. 3  is a cross-sectional view depicting an example CMP cleaning system according to some embodiments of the present invention. 
           [0011]      FIG. 4  is a perspective diagram depicting an example outer partition of a CMP cleaning system according to some embodiments of the present invention. 
           [0012]      FIG. 5  is a magnified perspective diagram depicting details of an upper portion of the example outer partition of  FIG. 4  according to some embodiments of the present invention. 
           [0013]      FIG. 6  is a magnified perspective diagram depicting details of the portion of the example outer partition in the area labeled A in  FIG. 5  according to some embodiments of the present invention. 
           [0014]      FIG. 7  is a magnified perspective diagram depicting details of a lower portion of an example outer partition of a CMP cleaning system according to some embodiments of the present invention. 
           [0015]      FIG. 8  is a perspective diagram depicting an example inner partition of a CMP cleaning system according to some embodiments of the present invention. 
           [0016]      FIG. 9  is a cross-sectional diagram depicting features of an example inner partition of a CMP cleaning system according to some embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Inventive embodiments of methods and apparatus are provided for isolating a running beam conveyor of a CMP cleaning system from the cleaning environment in which the CMP cleaning system is operated. The inventors of the present invention have noticed that the running beam conveyor used to move substrates from the factory interface to the cleaning modules and to the CMP polisher is a potential source of particle contaminants on processed substrates. Specifically, the actuators, motor drive, and other mechanical parts of the running beam conveyor that physically interact, generate particles (e.g., due to friction) and thus, may contaminate the adjacent cleaning modules and the substrates. In some embodiments, the present invention provides methods and apparatus to partition and isolate the running beam conveyor from the remainder of the cleaning system. In some embodiments, a series of interlocking, removable, partition panels are used to surround the running beam conveyor and to isolate the conveyor. 
         [0018]    Turning to  FIG. 1 , an example CMP cleaning system  100  according to the present invention is depicted as a top-view schematic block diagram. The system  100  includes a factory interface  102  for loading and unloading substrates from the system  100 . The factory interface  102  may include various robots and load ports adapted to receive substrates to be processed and to present substrates that have been processed (e.g., cleaned, planarized, and polished). A running beam conveyor  104  is adapted to move substrates from and to the factory interface  102 . The running beam conveyor is also adapted to move substrates through and between the various cleaning modules  106  and the CMP polisher  108 . The system  100  also includes an input/output shuttle  110  disposed between the factory interface  102  and the polisher  108 . Disposed on either side of the running beam conveyor  104  and extending from the factory interface  102  to the polisher  108 , are an inner partition  112  and an outer partition  114 . The partitions  112 ,  114  are configured to provide a barrier between the running beam conveyor  104  and the cleaning modules  106  to prevent any particles generated by the operation of the running beam conveyor  104  from entering the cleaning modules  106  and thereby potentially contaminating substrates being processed within the cleaning modules  106 . The partitions  112 ,  114  are described below in more detail. 
         [0019]      FIG. 2  depicts the CMP cleaning system  100  in a cross-sectional perspective view with the factory interface  102  not present. The tops of the cleaning modules  106  are seen in the foreground and the outer partition  114  is disposed next to the cleaning modules  106 . The running beam conveyor  104  is shown isolated from the cleaning modules  106  between the outer partition  114  and the inner partition  112 . A pass through  202  is shown on the far side of the inner partition  112 . 
         [0020]    As can be seen in  FIG. 2 , the depicted example embodiment of the outer partition  114  includes a number of panels (e.g., four) coupled together to form the partition  114 . Likewise, the inner partition  112  can be so formed. In some embodiments, multiple panels can be used to form the partitions  112 ,  114  and in other embodiments, a single panel can be used. By providing a partition  112 ,  114  that uses multiple panels however, the system  100  remains modular and any length partition can be assembled to accommodate any number of cleaning modules  106 . Thus, for example, in some embodiments, the partition panels can be wide enough to span the width of a single cleaning module  106  such that the total width of the assembled partitions  112 ,  114  can be configured to match the length of the line of cleaning modules  106  by adding a pair of panels (one for each partition  112 ,  114 ) for each cleaning module in the system. 
         [0021]    In the particular example embodiment shown in  FIG. 2 , the outer partition  114  includes four panels and each panel is approximately 338 mm wide and approximately 924 mm high. Thus, the outer partition  114  formed by the four panels assembled together is approximately 1352 mm wide and approximately 924 mm high. Other size panels can be used. For example, two panels with a width of approximately 676 mm can be used to form an outer partition  114  of the same size. Likewise, the inner partition  112  can be so formed. 
         [0022]    In some embodiments, the partition panels can be constructed from polyvinyl chloride (PVC) or other suitable material. Clear PVC can be used to allow viewing of operation of the running beam conveyor  104  and other components. PVC in particular is suitable and compatible with clean room applications and can be manufactured to meet the FM4910 Fire-Safe Plastics standard. Other materials meeting this standard and being compatible with clean room applications can also be used. 
         [0023]    The thickness of the material used to manufacture the panels can be selected to provide good durability, structural integrity, and still be relatively light weight. In some embodiments, approximately ⅜ inch thick material can be used. Other thicknesses can be used in other embodiments. 
         [0024]    Turning now to  FIG. 3 , a cross-sectional end-view of the CMP cleaning system  100  is depicted from the factory interface  102  end of the system  100 . The running beam conveyor  104  ( FIG. 2 ) can be more clearly seen between the outer partition  114  and the inner partition  112 .  FIG. 3  also illustrates a substrate gripper  302  (e.g., a U-shaped gripper) adapted to hold the substrates during conveyance and to pick-up individual substrates from the cleaning modules  106 . The example embodiment of a substrate gripper  302  shown in  FIG. 3  extends over the outer partition  114  to access the cleaning modules  106 . 
         [0025]    The running beam driver  304  (e.g., an actuator for the conveyor  104 ) is shown disposed between the outer partition  114  and the inner partition  112 . An exhaust port  306  for the running beam conveyor is provided to vent the particles generated by the driver  304  and other moving parts. In some embodiments, a down draft, vacuum pressure may be provided at the exhaust port to pull any particles from the running beam conveyor  104  out of the system  100 . Thus, in some embodiments, the panels of the partitions  112  and  114  can be coupled together to create a seal that allows a negative vacuum pressure to be established between the partitions  112 ,  114 . 
         [0026]    Turning to  FIG. 4 , details of the outer partition  114  are illustrated in a partial perspective view of the system  100 . In some embodiments, a stainless steel (SST) supporting wire  402  supports an arrangement of SST frames  404  and a series of interlocking panels  406 . Other materials may be used. As shown in  FIG. 5 , the supporting wire  402  is tensioned using a fastener  502  (e.g., a tightening nut on a threaded end of the supporting wire  402 ).  FIG. 6  is a magnified perspective diagram depicting the portion of  FIG. 5  labeled A. Area A illustrates an over-lapping, inter-locking joint  602  between the frames  404  and the panels  406 . This inter-locking joint  602  allows the panels  406  to be sealably coupled together to contain any contaminates and to prevent any airflow through the partition  114 . 
         [0027]      FIG. 7  is a magnified perspective diagram depicting the lower portion of the outer partition  114 . A sealing member (e.g., a rubber seal) may be provided along the base of the outer partition  114  to seal the bottom of the partition  114  against the support rail  702 . In some embodiments, the outer partition  704  may include a clearance contour  704  to provide improved access to the cleaning modules  106 . For example, the clearance contour  704  in the embodiment shown in  FIG. 7  bends away from the major surface of the panel  406  at approximately 54 degrees and extends away from the major surface approximately 25 mm. This clearance contour  704  provides a space immediately above and adjacent to the cleaning modules  106  ( FIG. 2 ), i.e., for substrate handling, gripper  302  ( FIG. 3 ) clearance, and/or cleaning module  106  operation. Although only a single clearance contour  704  is depicted on the outer partition  114  in the particular example embodiment shown in the drawings, any number of clearance contours can be provided on either partition  112 ,  114  to accommodate operation of stationary and moving parts of the system  100 . In other words, the partitions  112 ,  114  can have any shape needed to accommodate the system  100 . 
         [0028]      FIG. 8  provides a perspective view of an example embodiment of an inner partition  112 . The inner partition  112  may include a removable, sealable access window  802  supported by a frame  804 . In some embodiments, the frame may be constructed of SST and the window may be constructed of clear PVC. A series of fasteners  806  disposed around the perimeter may be used to hold the window  802  in place and a seal  808  (i.e., a rubber seal) may be provided at the lower edge of the window  802 . The fasteners  806  may be, for example, quarter turn fasteners made of black nylon and commercially available from Southco, Inc. of Concordville, Pa. 
         [0029]      FIG. 9  is a cross-sectional diagram depicting an end view of an embodiment of the inner partition  112 . In some embodiments, the inner partition  112  can include a drip rail  902  along the lower edge of the base of the partition  112  as illustrated in  FIG. 9 . The example drip rail  902  depicted extends from the inner partition  112  at an angle of approximately 78 degrees and reaches approximately 48 mm from the mounting surface on the inner partition  112 . As discussed above, in some embodiments, the inner partition  112  may also include one or more a contours  904  to accommodate other components (e.g., the running beam conveyor  104 ) of the system  100 . 
         [0030]    Accordingly, while the present invention has been disclosed in connection with the preferred embodiments thereof, it should be understood that other embodiments may fall within the scope of the invention, as defined by the following claims.