Polishing composition, method for producing polishing composition, polishing method, and method for producing semiconductor substrate

Abstract

A polishing composition according to the present invention includes: silica; an anionic water-soluble polymer; at least one compound selected from the group consisting of a phosphonate group-containing compound, a phosphate group-containing compound, and an amino group-containing compound; and a dispersing medium.

1 .- 12 . (canceled) 
     
     
         13 . A polishing composition comprising:
 silica;   an anionic water-soluble polymer;   at least one compound selected from the group consisting of a phosphonate group-containing compound, a phosphate group-containing compound, and an amino group-containing compound; and   a dispersing medium,   wherein an anionic group of the anionic water-soluble polymer is selected from the group consisting of a carboxylic group (carboxyl group), a sulfonic group, a sulfuric acid ester group, a phosphoric acid ester group, and a phosphonate group, and a content of the anionic water-soluble polymer is 1600 ppm or more.   
     
     
         14 . The polishing composition according to  claim 13 , wherein the anionic water-soluble polymer comprises a (co)polymer having a constituent unit derived from a monomer having a carboxylic group and a salt thereof. 
     
     
         15 . The polishing composition according to  claim 14 , wherein the monomer having a carboxylic group is selected from the group consisting of itaconic acid, (meth)acrylic acid, maleic acid and a salt thereof. 
     
     
         16 . The polishing composition according to  claim 13 , wherein the anionic water-soluble polymer is selected from the group consisting of polyacrylic acid, polyacrylic acid salt, (acrylic acid-maleic acid) copolymer and (acrylic acid-maleic acid) salt copolymer. 
     
     
         17 . The polishing composition according to  claim 13 , wherein a weight average molecular weight of the anionic water-soluble polymer is 1000 or more. 
     
     
         18 . The polishing composition according to  claim 13 , wherein the phosphonate group-containing compound has one to six phosphonate groups. 
     
     
         19 . The polishing composition according to  claim 13 , wherein the phosphonate group-containing compound is at least one selected from the group consisting of 1-hydroxyethane-1,1-diphosphonic acid, nitrilotris(methylenephosphonic acid), ethylenediamine tetramethylene phosphonic acid, and diethylenetriamine penta(methylenephosphonic acid). 
     
     
         20 . The polishing composition according to  claim 13 , wherein a pH of the polishing composition is 2.5 or less. 
     
     
         21 . The polishing composition according to  claim 13 , wherein the polishing composition is used in a step of polishing an object to be polished containing silicon nitride and titanium nitride. 
     
     
         22 . A method for producing the polishing composition according to  claim 13 , the method comprising mixing the silica, the anionic water-soluble polymer, the at least one compound selected from the group consisting of a phosphonate group-containing compound having one to six phosphonate groups, and the dispersing medium,
 wherein an anionic group of the anionic water-soluble polymer is selected from the group consisting of a carboxylic group (carboxyl group), a sulfonic group, a sulfuric acid ester group, a phosphoric acid ester group, and a phosphonate group, and a content of the anionic water-soluble polymer is 1600 ppm or more.   
     
     
         23 . A polishing method comprising a step of polishing an object to be polished by using the polishing composition according to  claim 13 . 
     
     
         24 . The polishing method according to  claim 23 , wherein the object to be polished contains silicon nitride and titanium nitride. 
     
     
         25 . A method for producing a semiconductor substrate, the method comprising a step of polishing an object to be polished by the polishing method according to  claim 23 .