Polishing pad and method of use

Abstract

A polishing pad has one or more polishing elements made from a hydrogel material having an intrinsic ability to absorb water. The hydrogel material may or may not have micropores, but has a water absorption capability of 4%-60% by weight, a wet tensile strength greater than 1000 psi, a flexural modulus greater than 2000 psi, and a wet Shore D hardness between 25-80, inclusive. The hydrogel material may be made from one or a combination of the following moieties: urethane, alkylene oxides, esters, ethers, acrylic acids, acrylamides, amides, imides, vinylalcohols, vinylacetates, acrylates, methacrylates, sulfones, urethanes, vinylchlorides, etheretherketones, and/or carbonates.

1 . A polishing pad comprising one or more polishing elements, said polishing elements made from a hydrogel polymer having an intrinsic ability to absorb water and having no micro-porosity, the hydrogel material having a water absorption capability of 4%-60% by weight, a wet tensile strength greater than 1000 psi, a flexural modulus greater than 2000 psi, and a wet Shore D hardness between 25-80, inclusive. 
     
     
         2 . The polishing pad of  claim 1 , wherein the hydrogel material is made from one or a combination of the following moieties: urethane, alkylene oxides, esters, ethers, acrylic acids, acrylamides, amides, imides, vinylalcohols, vinylacetates, acrylates, methacrylates, sulfones, urethanes, vinylchlorides, etheretherketones, and/or carbonates. 
     
     
         3 . A method of polishing a wafer, comprising bringing a polishing pad constructed from a material having an intrinsic ability to absorb water in proximity to a semiconductor wafer in the presence of a polishing composition disposed between the polishing pad and a top layer disposed on the wafer, and rotating the wafer and the polishing pad with respect to one another so as to effect removal of some or all of the top layer disposed on the wafer. 
     
     
         4 . The method of  claim 3 , further comprising soaking the polishing pad in solution prior to commencing polishing operations. 
     
     
         5 . The method of  claim 4 , wherein the solution comprises water. 
     
     
         6 . The method of  claim 4 , wherein the solution comprises the polishing composition. 
     
     
         7 . The method of  claim 4 , wherein the soaking lasts for at least 10 minutes. 
     
     
         8 . The method of  claim 4 , wherein the solution is an electrolyte solution. 
     
     
         9 . The method of  claim 8 , wherein the electrolyte solution is copper sulfate. 
     
     
         10 . The method of  claim 9 , wherein during the polishing operations, the polishing pad is coupled to an electrical source. 
     
     
         11 . The method of  claim 10 , wherein the electrical connection to the pad is anodic. 
     
     
         12 . The method of  claim 10 , wherein the electrical connection to the pad is cathodic. 
     
     
         13 . A polishing pad comprising one or more polishing elements, said polishing elements made from a hydrogel material having a water absorption capability of 4%-60% by weight, a microporosity of 1% to 20% by volume, micropores of 20-100 microns, a wet tensile strength greater than 1000 psi, a flexural modulus greater than 2000 psi, and a wet Shore D hardness between 25-80, inclusive. 
     
     
         14 . The polishing pad of  claim 13 , wherein the hydrogel material is made from one or a combination of the following moieties: urethane, alkylene oxides, esters, ethers, acrylic acids, acrylamides, amides, imides, vinylalcohols, vinylacetates, acrylates, methacrylates, sulfones, urethanes, vinylchlorides, etheretherketones, and/or carbonates. 
     
     
         15 . A method of polishing a wafer, comprising soaking a polishing pad having a polishing surface constructed from a material having an intrinsic ability to absorb water in an electrolytic solution, bringing the polishing surface of the polishing pad in proximity to a semiconductor wafer in the presence of a polishing composition disposed between the polishing pad and a top layer disposed on the wafer, and rotating the wafer and the polishing pad with respect to one another so as to effect removal of some or all of the top layer disposed on the wafer. 
     
     
         16 . The method of  claim 15 , wherein the electrolytic solution is copper sulfate. 
     
     
         17 . The method of  claim 15 , wherein the polishing surface is attached to an electrical source during polishing operations. 
     
     
         18 . The method of  claim 17 , wherein the electrical connection to the polishing surface is anodic. 
     
     
         19 . The method of  claim 17 , wherein the electrical connection to the polishing surface is cathodic. 
     
     
         20 . The method of  claim 15  further comprising applying an anodic current to the polishing surface while a cathodic bias is provided by external means, and pressing the semiconductor wafer against the polishing surface. 
     
     
         21 . The method of  claim 20 , wherein the electrolytic solution is copper sulfate. 
     
     
         22 . The method of  claim 20 , wherein the top layer is copper. 
     
     
         23 . The method of  claim 15 , further comprising applying an anodic current to the polishing surface while an anodic bias is provided by external means, and pressing the semiconductor wafer against the polishing surface. 
     
     
         24 . The method of  claim 23 , wherein the electrolytic solution is copper sulfate. 
     
     
         25 . The method of  claim 23 , wherein the top layer is copper. 
     
     
         26 . A method, comprising manufacturing a polishing pad having a polishing surface constructed from a material having an intrinsic ability to absorb water using one of: injection molding, extrusion, reaction injection molding or sintering. 
     
     
         27 . The method of  claim 26 , further comprising forming surface features on the polishing surface of the polishing pad during said manufacturing.