Negative poisson's ratio material-containing CMP polishing pad

Abstract

The invention is directed to a chemical-mechanical polishing pad comprising a porous polymeric material, wherein the porous polymeric material has a Poisson's ratio less than 0. The invention further provides a method of polishing a workpiece comprising (i) providing a workpiece to be polished, (ii) contacting the workpiece with a chemical-mechanical polishing system comprising the polishing pad of the invention, and (iii) abrading at least a portion of the surface of the workpiece with the polishing system to polish the workpiece.

1 . A chemical-mechanical polishing pad comprising a porous polymeric material, wherein the porous polymeric material has a Poisson's ratio less than 0.  
     
     
         2 . The polishing pad of  claim 1 , wherein the porous polymeric material has a Poisson's ratio of from about −1 to less than 0.  
     
     
         3 . The polishing pad of  claim 2 , wherein the porous polymeric material has a Poisson's ratio of from about −0.8 to about −0.2.  
     
     
         4 . The polishing pad of  claim 1 , wherein the porous polymeric material is a thermoplastic polymer or a thermoset polymer.  
     
     
         5 . The polishing pad of  claim 4 , wherein the thermoplastic polymer or the thermoset polymer is selected from the group consisting of polyurethanes, polyolefins, polyvinylalcohols, polyvinylacetates, polycarbonates, polyacrylic acids, polyacrylamides, polyethylenes, polypropylenes, nylons, fluorocarbons, polyesters, polyethers, polyamides, polyimides, polytetrafluoroethylenes, polyetheretherketones, copolymers thereof, and mixtures thereof.  
     
     
         6 . The polishing pad of  claim 5 , wherein the thermoplastic polymer or the thermoset polymer is selected from the group consisting of polyurethanes and polyolefins.  
     
     
         7 . The polishing pad of  claim 1 , wherein the polishing pad has a density of about 1 g/cm 3  or less.  
     
     
         8 . The polishing pad of  claim 1 , wherein the polishing pad has a void volume of about 75% or less.  
     
     
         9 . The polishing pad of  claim 1 , wherein the polishing pad has a pore density of greater than about 10 pores/cm.  
     
     
         10 . The polishing pad of  claim 1 , wherein the pore size is from about 0.1 μm to about 2500 μm.  
     
     
         11 . The polishing pad of  claim 1 , wherein the polishing pad further comprises a polishing surface comprising grooves.  
     
     
         12 . The polishing pad of  claim 11 , wherein the grooves are linear grooves.  
     
     
         13 . The polishing pad of  claim 11 , wherein the grooves are in the form of an XY crosshatch.  
     
     
         14 . The polishing pad of  claim 1 , wherein the polishing pad further comprises a substantially optically transmissive region.  
     
     
         15 . The polishing pad of  claim 14 , wherein the substantially optically transmissive region has a light transmission of at least 10% at one or more wavelengths between from about 190 nm to about 3500 nm.  
     
     
         16 . The polishing pad of  claim 1 , wherein the polishing pad further comprises abrasive particles.  
     
     
         17 . The polishing pad of  claim 16 , wherein the abrasive particles comprise metal oxide selected from the group consisting of alumina, silica, titania, ceria, zirconia, germania, magnesia, co-formed products thereof, and combinations thereof.  
     
     
         18 . The method of polishing a substrate comprising 
 (i) providing a substrate to be polished,    (ii) contacting the substrate with a chemical-mechanical polishing system comprising a polishing pad comprising a porous polymeric material, wherein the porous polymeric material has a Poisson's ratio less than 0, and    (iii) abrading at least a portion of the surface of the substrate with the polishing system to polish the substrate.    
     
     
         19 . The method of  claim 18 , wherein the polishing pad further comprises abrasive particles.  
     
     
         20 . The method of  claim 19 , wherein the abrasive particles comprise metal oxide selected from the group consisting of alumina, silica, titania, ceria, zirconia, germania, magnesia, co-formed products thereof, and combinations thereof.  
     
     
         21 . The method of  claim 18 , wherein the method further comprises detecting in situ a polishing endpoint.