Polishing composition and polishing method

Abstract

A polishing composition contains at least one water soluble polymer selected from the group consisting of polyvinylpyrrolidone and poly(N-vinylformamide), and an alkali, and preferably further contains at least one of a chelating agent and an abrasive grain. The water soluble polymer preferably has a weight average molecular weight of 6,000 to 4,000,000. The polishing composition is mainly used in polishing of the surfaces of semiconductor wafers such as silicon wafers, especially used in preliminary polishing of the surfaces of such wafers.

1 . A polishing composition comprising:
 at least one water soluble polymer selected from the group consisting of polyvinylpyrrolidone and poly(N-vinylformamide); and   an alkali, wherein the water soluble polymer is contained in an amount of 0.0003 to 0.1 g/L in the polishing composition.   
     
     
         2 . The polishing composition according to  claim 1 , wherein the water soluble polymer is contained in an amount of 0.003 to 0.015 g/L in the polishing composition. 
     
     
         3 . The polishing composition according to  claim 2 , wherein the water soluble polymer is contained in an amount of 0.005 to 0.01 g/L in the polishing composition. 
     
     
         4 . The polishing composition according to  claim 1 , wherein the water soluble polymer has a weight average molecular weight of 6,000 to 4,000,000. 
     
     
         5 . The polishing composition according to  claim 1 , wherein the alkali is selected from the group consisting of alkali metal hydroxides, ammonia, amines, and quaternary ammonium salts. 
     
     
         6 . The polishing composition according to  claim 5 , wherein the alkali is selected from the group consisting of alkali metal hydroxides and quaternary ammonium salts. 
     
     
         7 . The polishing composition according to  claim 6 , wherein the alkali is contained in the polishing composition in an amount of 0.1 to 5 g/L. 
     
     
         8 . The polishing composition according to  claim 7 , wherein the alkali is contained in the polishing composition in an amount of 0.5 to 3 g/L. 
     
     
         9 . The polishing composition according to  claim 1 , further comprising a chelating agent. 
     
     
         10 . The polishing composition according to  claim 9 , wherein the chelating agent is an aminocarboxylic acid-based chelating agent. 
     
     
         11 . The polishing composition according to  claim 9 , wherein the chelating agent is a phosphonic acid-based chelating agent. 
     
     
         12 . The polishing composition according to  claim 1 , further comprising abrasive grains of colloidal silica or fumed silica. 
     
     
         13 . A polishing composition comprising:
 polyvinylpyrrolidone of a content in a range of from 0.005 to 0.01 g/L;   an alkali of a content in a range of from 0.5 to 3 g/L;   colloidal silica or fumed silica of a content in a range of 5 to 25 g/L; and   water; wherein the polishing composition is used for polishing a silicon wafer surface.   
     
     
         14 . The polishing composition according to  claim 13 , further comprising a chelating agent of a content of about 0.3 g/L. 
     
     
         15 . A method of polishing, comprising polishing a surface of a semiconductor wafer using a polishing composition, and the polishing composition contains:
 at least one water soluble polymer selected from the group consisting of polyvinylpyrrolidone and poly(N-vinylformamide); and   an alkali, wherein the water soluble polymer is contained in an amount of 0.0003 to 0.1 g/L in the polishing composition.