Vacuum mount wafer polishing methods and apparatus

Abstract

The present invention provides exemplary methods, systems and apparatus that provide improved substrate characteristics. The present invention may be used in conjunction with or after grinding operations prior to circuit device formation, or alternatively in conjunction with CMP operations on a device wafer between device process steps. In one embodiment, an apparatus ( 100 ) for processing a substrate ( 118 ) includes a rotatable first spindle ( 110 ) having a grind pattern coupled thereto for grinding the substrate. The first spindle is further adapted to receive a polishing pad ( 200 ). The apparatus includes a second spindle ( 116 ) adapted to hold the substrate, and a gimbal device ( 150 ) coupled to the first spindle and adapted to provide three axis movement thereof. In this manner, the same apparatus may be used for both grinding and polishing of a wafer.

What is claimed is:  
     
         1 . An apparatus for processing a substrate, said apparatus comprising: 
 a rotatable first spindle having a grind pattern coupled thereto for grinding said substrate, said first spindle further adapted to receive a polishing pad;    a second spindle adapted to hold said substrate to be ground; and    a gimbal device coupled to said first spindle and adapted to provide three axis movement of said first spindle.    
     
     
         2 . The apparatus as in  claim 1  wherein said first spindle comprises a removable grind ring having said grind pattern, said first spindle adapted to receive said polishing pad after said grind ring is removed.  
     
     
         3 . The apparatus as in  claim 1  further comprising a vacuum mount apparatus coupled to said second spindle and adapted to hold said substrate to said second spindle with a vacuum.  
     
     
         4 . The apparatus as in  claim 1  further comprising a rotation device coupled to said second spindle for rotating said second spindle.  
     
     
         5 . The apparatus as in  claim 1  further comprising a cleaner, said cleaner adapted to clean said wafer while said wafer is mounted to said second spindle.  
     
     
         6 . The apparatus as in claim I further comprising a wafer thickness monitor for in situ monitoring of wafer thickness during grinding and polishing of said wafer.  
     
     
         7 . A method of processing a substrate, said method comprising: 
 mounting a substrate to a grinder, said grinder having a grind platen and a substrate platen to which said substrate is mounted;    grinding a substrate surface with said grind platen;    mounting a polishing pad to said grind platen while said substrate remains mounted to said substrate platen; and    polishing said substrate surface with said polishing pad.    
     
     
         8 . The method as in  claim 7  wherein said mounting comprises mounting said substrate with a vacuum.  
     
     
         9 . The method as in  claim 8  wherein said vacuum is maintained during said grinding, said mounting said polishing pad, and said polishing.  
     
     
         10 . The method as in  claim 7  wherein said polishing pad comprises an annular ring polishing pad.  
     
     
         11 . The method as in  claim 7  wherein said grind platen further comprises a removable annular grind ring, and further comprising removing said grind ring before said mounting said polishing pad.  
     
     
         12 . The method as in  claim 11  wherein said polishing pad comprises an annular ring polishing pad, said polishing pad having a greater pad surface area than a grind area of said annular grind ring.  
     
     
         13 . The method as in  claim 7  wherein said polishing pad comprises a plurality of polishing segments disposed on an annular ring, said annular ring further comprising a plurality of spaced apart slurry ports adapted to deliver slurry to said substrate surface, and wherein at least some of said slurry ports are disposed between at least some of said polishing segments.  
     
     
         14 . The method as in  claim 7  wherein said polishing comprises providing relative rotation between said substrate and said polishing pad, while contacting said substrate surface with said polishing pad with sufficient force to decrease a thickness of said wafer by between about one (1) micron and about three (3) microns per minute.  
     
     
         15 . The method as in  claim 7  wherein said polishing comprises rotating said grind platen at between about 1,000 RPM and about 7,000 RPM.  
     
     
         16 . The method as in  claim 15  wherein said polishing further comprises rotating said substrate platen in a direction generally opposite the rotation of said grind platen.  
     
     
         17 . The method as in  claim 7  further comprising gimbaling said grind platen so that an exposed surface of said polishing pad is not parallel to said substrate surface.  
     
     
         18 . The method as in  claim 17  wherein said gimbaling comprises gimbaling said grind platen subsequent to said grinding and prior to said polishing.  
     
     
         19 . The method as in  claim 17  wherein said polishing removes a high point on said substrate surface.  
     
     
         20 . The method as in  claim 7  wherein said polishing comprises introducing a slurry having a pH between about 8.5 and about 13.