Polishing pad with wear indicator for profile monitoring and controlling and method and apparatus for polishing using said pad

Abstract

A polishing pad includes a body formed of a polishing pad material and having a top polishing surface and a bottom surface; and an indicator disposed in said body and extending from an upper region of the body near the top polishing surface toward said bottom surface, for indicating wear of the polishing pad body during a life cycle of the polishing pad. An apparatus for polishing semiconductor wafers includes a polishing platen; a motor for rotating the polishing platen; and a polishing pad as described above mounted on the polishing platen. A method of polishing semiconductor wafers includes optically inspecting the indicator means to determine the wear of the body.

What is claimed is:  
     
         1 . A polishing pad comprising: 
 a body formed of a polishing pad material and having a top polishing surface and a bottom surface; and    indicator means disposed in said body and extending from a region at or near said top polishing surface toward said bottom surface to a predetermined depth, for indicating wear of said body during a life cycle of said polishing pad.    
     
     
         2 . The polishing pad of  claim 1 , wherein said indicator means includes at least one insert member provided in a recess formed in said top polishing surface.  
     
     
         3 . The polishing pad of  claim 1 , wherein said recess extends across a widest part of said top polishing surface.  
     
     
         4 . The polishing pad of  claim 2 , wherein said at least one insert member has a uniform optical contrast with respect to said polishing pad material.  
     
     
         5 . The polishing pad of  claim 4 , wherein said optical contrast provides an in-line indication of wear of said body.  
     
     
         6 . The polishing pad of  claim 5 , wherein said predetermined depth is less than a distance between said top polishing surface and said bottom surface such that an absence of said optical contrast provides an in-line indication of polishing pad end-of-life.  
     
     
         7 . The polishing pad of  claim 5 , wherein said at least one insert member varies in width over said predetermined depth for indicating wear of said body, and wherein variation of said width comprises one of decreasing in size and increasing in size in a direction from said top polishing surface toward said bottom surface.  
     
     
         8 . The polishing pad of  claim 1 , wherein said indicator means includes a plurality of periodically placed insert members provided in a corresponding plurality of holes in said body.  
     
     
         9 . The polishing pad of  claim 8 , wherein said plurality of holes extend across a widest part of said top polishing surface.  
     
     
         10 . The polishing pad of  claim 8 , wherein said plurality of insert members have a uniform optical contrast with respect to said polishing pad material.  
     
     
         11 . The polishing pad of  claim 8 , wherein said optical contrast provides an in-line indication of wear of said body.  
     
     
         12 . The polishing pad of  claim 11 , wherein said predetermined depth is less than the distance between said top polishing surface and said bottom surface such that an absence of said high contrast provides an in-line indication of polishing pad end-of-life.  
     
     
         13 . The polishing pad of  claim 12 , wherein each of said plurality of insert members varies in width over said predetermined depth for indicating wear of said body, and wherein variation of said width of each of said plurality of insert members comprises one of decreasing in size and increasing in size in a direction from said top polishing surface toward said bottom surface.  
     
     
         14 . An apparatus for polishing semiconductor wafers, comprising: 
 a polishing platen;    a motor for rotating the polishing platen; and    a polishing pad mounted on the polishing platen, said polishing pad comprising: 
 a body formed of a polishing pad material and having a top polishing surface and a bottom surface; and  
 indicator means disposed in said body and extending from a region at or near said top polishing surface toward said bottom surface to a predetermined depth, for indicating wear of said body during a life cycle of said polishing pad.  
   
     
     
         15 . The polishing pad of  claim 14 , wherein said indicator means includes at least one insert member provided in a recess formed in said top polishing surface.  
     
     
         16 . The polishing pad of  claim 14 , wherein said recess extends across a widest part of said top polishing surface.  
     
     
         17 . The polishing pad of  claim 15 , wherein said at least one insert member has a uniform optical contrast with respect to said polishing pad material.  
     
     
         18 . The polishing pad of  claim 17 , wherein said optical contrast provides an in-line indication of wear of said body.  
     
     
         19 . The polishing pad of  claim 18 , wherein said predetermined depth is less than a distance between said top polishing surface and said bottom surface such that an absence of said optical contrast provides an in-line indication of polishing pad end-of-life.  
     
     
         20 . The polishing pad of  claim 19 , wherein said at least one insert member varies in width over said predetermined depth for indicating wear of said body, and wherein variation of said width comprises one of decreasing in size and increasing in size in a direction from said top polishing surface toward said bottom surface.  
     
     
         21 . The polishing pad of  claim 14 , wherein said indicator means includes a plurality of periodically placed insert members provided in a corresponding plurality of holes in said body.  
     
     
         22 . The polishing pad of  claim 21 , wherein said plurality of holes extend across a widest part of said top polishing surface.  
     
     
         23 . The polishing pad of  claim 21 , wherein said plurality of insert members have a uniform optical contrast with respect to said polishing pad material.  
     
     
         24 . The polishing pad of  claim 21 , wherein said optical contrast provides an in-line indication of wear of said body.  
     
     
         25 . The polishing pad of  claim 24 , wherein said predetermined depth is less than the distance between said top polishing surface and said bottom surface such that an absence of said high contrast provides an in-line indication of polishing pad end-of-life.  
     
     
         26 . The polishing pad of  claim 24 , wherein each of said plurality of insert members varies in width over said predetermined depth for indicating wear of said body, and wherein variation of said width of each of said plurality of insert members comprises one of decreasing in size and increasing in size in a direction from said top polishing surface toward said bottom surface.  
     
     
         27 . A method of polishing a semiconductor wafer with a polishing apparatus, comprising the steps of: 
 providing a body formed of a polishing pad material and having a top polishing surface and a bottom surface and indicator means disposed in said body and extending from a region at or near said top polishing surface toward said bottom surface to a predetermined depth, for indicating wear of said body during a life cycle of said polishing pad depth; and    optically inspecting said indicator means to determine said wear of said body.