Patent ID: 7837800

Claim:
A polishing method for polishing a film to be polished formed on a substrate using a CMP polishing slurry, wherein said film to be polished comprises silicon oxide film, wherein the polishing method comprises the following steps: a step to prepare a substrate on which said film comprising silicon oxide film is formed; and a step to polish said film wherein the substrate is pushed against a polishing cloth of a polishing table and pressure is applied to the substrate while a CMP polishing slurry is supplied between said film and the polishing cloth, wherein said CMP polishing slurry comprises cerium oxide particles, a dispersing agent, a water-soluble polymer and water, wherein the added amount of the water-soluble polymer is 0.01 part or more by weight and 10 parts or less by weight for 100 parts by weight of the polishing slurry and wherein the water soluble polymer is a polymer containing a structural unit made of at least one polymerizable monomer selected from the group consisting of the following general formula (I): wherein R 1 represents hydrogen, a methyl group, a phenyl group, a benzyl group, a chloro group, a difluoromethyl group, a trifluoromethyl group, or a cyano group; and R 2 and R 3 each independently represent hydrogen, an alkyl chain of C 1 to C 18 , a methylol group, or an acetyl group provided that the case that both of R 2 and R 3 are hydrogen is excluded.