Patent ID: 8492276

Claim:
A chemical mechanical polishing method comprising: polishing a polishing target with a chemical polishing aqueous dispersion, wherein said polishing target comprises a tungsten film and a silicon oxide film wherein said chemical mechanical polishing aqueous dispersion comprises: (A) a cationic water-soluble polymer; (B) an iron (III) compound; and (C) colloidal silica particles, the content (M A ) (mass %) of the cationic water-soluble polymer (A) is 0.005 to 0.5 mass %, the content (M B ) (mass %) of the iron (III) compound (B) is 0.01 to 40 mass %, and the content (M c ) (mass %) of the colloidal silica particles (C) is 1 to 40 mass %, the content (M A ) (mass %) of the cationic water-soluble polymer (A) and the content (M B ) (mass %) of the iron (III) compound (B) satisfying the relationship “M A /M B =0.004 to 0.1”; the chemical mechanical polishing aqueous dispersion having a pH of 1 to 3; and the chemical mechanical polishing aqueous dispersion having a selectivity ratio (polishing rate of the tungsten film/polishing rate of the silicon oxide film) of 0.7 to 1.3.