Patent ID: 7677956

Claim:
A method of polishing a substrate comprising: (i) contacting a substrate having a surface area comprising a dielectric layer with a chemical-mechanical polishing composition comprising: (a) an abrasive consisting essentially of aggregated silica, (b) an acid, wherein the acid is an anionic polymer or copolymer, and wherein the anionic polymer or copolymer comprises repeating units selected from the group consisting of styrenesulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, salts thereof, and combinations thereof, and (c) a liquid carrier, wherein the dielectric layer comprises about 95% or more of the total surface area of the substrate, and wherein the polishing composition has a pH of about 3 or less, and (ii) abrading at least a portion of the substrate to polish the dielectric layer.