Polishing pad and method for manufacturing the polishing pad

Abstract

A polishing pad is disclosed which is less likely to cause scratches, and has an excellent planarization performance and polishing stability. In one aspect, the invention provides a polishing pad comprising an ultrafine fiber-entangled body formed of ultrafine fibers having an average fineness of 0.01 to 0.8 dtex, and a polymeric elastomer. The polymeric elastomer has a glass transition temperature of −10° C. or below, storage moduli at 23° C. and 50° C. of 90 to 900 MPa, and a water absorption ratio, when saturated with water at 50° C., of 0.2 to 5 mass %.

1 . A polishing pad, comprising:
 an ultrafine fiber-entangled body comprising at least one ultrafine fiber having an average fineness of 0.01 to 0.8 dtex; and   a polymeric elastomer,   wherein the polymeric elastomer has a glass transition temperature of −10° C. or below, storage moduli at 23° C. and 50° C. of 90 to 900 MPa, and a water absorption ratio, when saturated with water at 50° C., of 0.2 to 5 mass %.   
     
     
         2 . The polishing pad according to  claim 1 , wherein the ultrafine fiber-entangled body comprises at least one bundle of 5 to 70 ultrafine fibers, and the polymeric elastomer is present inside the at least one bundle. 
     
     
         3 . The polishing pad according to  claim 1 , wherein the at least one ultrafine fiber comprises at least one polyester fiber. 
     
     
         4 . The polishing pad according to  claim 1 , wherein the ultrafine fiber comprises a thermoplastic resin having a water absorption ratio, when saturated with water at 50° C., of 0.2 to 2 mass %. 
     
     
         5 . The polishing pad according to  claim 1 , wherein the polymeric elastomer is a polyurethane resin obtained by employing a polyol, a polyamine and a polyisocyanate, and wherein 60 to 100 mass % of the polyol is a noncrystalline polycarbonate diol. 
     
     
         6 . The polishing pad according to  claim 5 , wherein the polymeric elastomer is a polyurethane resin obtained by employing a noncrystalline polycarbonate diol together with a carboxylic group-containing diol, and an alicyclic diisocyanate. 
     
     
         7 . The polishing pad according to  claim 1 , wherein the polymeric elastomer has a ratio of the storage modulus at 23° C. to the storage modulus at 50° C. being 4 or less. 
     
     
         8 . The polishing pad according to  claim 1 , wherein the polymeric elastomer is an aqueous polyurethane having an average particle size of from 0.01 to 0.2 μm. 
     
     
         9 . The polishing pad according to  claim 1 , wherein the mass ratio of the ultrafine fiber-entangled body and the polymeric elastomer is from 55/45 to 95/5. 
     
     
         10 . The polishing pad according to  claim 1 , wherein at least one void area in the polishing pad has a volume ratio of at least 50%. 
     
     
         11 . A method for manufacturing a polishing pad, comprising:
 filling an interior of at least one bundle of ultrafine fibers which have an average fineness of from 0.01 to 0.8 dtex with a polymeric elastomer having a glass transition temperature of −10° C. or below, storage moduli at 23° C. and 50° C. of from 90 to 900 MPa, and a water absorption ratio, when saturated with water at 50° C., of from 0.2 to 5 mass %.   
     
     
         12 . The method for manufacturing a polishing pad according to  claim 11 , wherein the polymeric elastomer is filled into the interior of an ultrafine fiber-entangled body comprising the at least one bundle of the ultrafine fibers such that at least one void area in the polishing pad has a volume ratio of at least 50%.