Polishing pad having edge surface treatment

Abstract

A polishing pad has a sublayer and a polishing layer, wherein the surface of the outer peripheral edge of the sublayer can be at least partially treated to reduce the absorption or permeation of polishing fluid into the sublayer through the outer peripheral edge. The application of the surface treatment at least reduces the amount of polishing fluid absorbed by the sublayer of the polishing pad during the polishing process. The polishing pad of the present invention is useful in polishing microelectronic substrates and especially useful in chemical mechanical planarization of semiconductor wafers.

1 . A polishing pad for use in polishing a microelectronic substrate comprising: 
 a polishing layer adapted to polish said substrate;    a sublayer of substantially liquid permeable material having an outer peripheral edge, wherein said polishing layer and said sublayer are at least partially connected; and    wherein at least a portion of said outer peripheral edge of said sublayer has a surface treatment, said surface treatment being effective to reduce absorption of polishing liquid through said outer peripheral edge while maintaining open pores in said outer peripheral edge.    
     
     
         2 . The polishing pad of  claim 1  wherein said polishing layer is substantially impermeable to polishing fluid.  
     
     
         3 . The polishing pad of  claim 1  wherein said polishing layer is substantially permeable to polishing fluid.  
     
     
         4 . The polishing pad of  claim 1  wherein said sublayer is more compressible than said polishing layer.  
     
     
         5 . The polishing pad of  claim 1  wherein said sublayer comprises material chosen from natural rubber, synthetic rubbers, thermoplastic elastomer, foam sheet and combinations thereof.  
     
     
         6 . The polishing pad of  claim 1  wherein said sublayer is connected to said polishing layer by means of a middle layer.  
     
     
         7 . The polishing pad of  claim 6  wherein at least a portion of said middle layer comprises a transparent material.  
     
     
         8 . The polishing pad of  claim 7  wherein said sublayer and said polishing layer contain an opening substantially aligned with said transparent portion of said middle layer.  
     
     
         9 . The polishing pad of  claim 1  wherein said outer peripheral edge can absorb organic liquids.  
     
     
         10 . The polishing pad of  claim 1  wherein said surface treatment comprises treatment of said sublayer with at least one material chosen from silanes, organic polymers, silane-treated silicas, and mixtures thereof.  
     
     
         11 . The polishing pad of  claim 10  wherein said surface treatment comprises treatment of said sublayer with at least one material chosen from alkyl silanes, polyolefins and mixtures thereof.  
     
     
         12 . A polishing pad for use in polishing a microelectronic substrate comprising: 
 a polishing layer adapted to polish said substrate;    a sublayer of substantially liquid permeable material having an outer peripheral edge, wherein said polishing layer and said sublayer are at least partially connected; and    wherein at least a portion of said outer peripheral edge has a surface treatment, said surface treatment being effective to render said outer peripheral edge substantially hydrophobic while maintaining open pores in said outer peripheral edge of said sublayer.    
     
     
         13 . A polishing pad for use in polishing a microelectronic substrate comprising: 
 a polishing layer adapted to polish said substrate;    a sublayer of substantially liquid permeable material having an outer peripheral edge, wherein said polishing layer and said sublayer are at least partially connected; and    wherein at least a portion of said outer peripheral edge has a surface treatment, said surface treatment being effective to reduce the wettability of said outer peripheral edge while maintaining open pores in said outer peripheral edge of said sublayer.    
     
     
         14 . A method of polishing a microelectronic substrate comprising: 
 surface treating an outer peripheral edge of a sublayer of a polishing pad, said pad being useful for polishing a microelectronic substrate and said sublayer comprising substantially liquid permeable material, wherein said surface treatment is effect to reduce the absorption of polishing fluid through said outer peripheral edge while maintaining open pores in said outer peripheral edge of said sublayer.    
     
     
         15 . A method of polishing a microelectronic substrate comprising: 
 at least partially applying to an outer peripheral edge of a sublayer of a polishing pad a surface treatment material, said material being effective to render said outer peripheral edge hydrophobic while maintaining open pores in said outer peripheral edge of said sublayer, said pad being useful for polishing a microelectronic substrate and said sublayer comprising substantially liquid permeable material.    
     
     
         16 . A method for reducing the absorption of polishing fluid through the outer peripheral edge of a sublayer of a polishing pad, comprising: surface treating at least a portion of said outer peripheral edge wherein said surface treating comprises applying to said outer peripheral edge of said sublayer at least one material chosen from silanes, organic polymers, silane-treated silicas, and mixtures thereof while maintaining open pores in said outer peripheral edge of said sublayer.