Patent ID: 8163650

Claim:
An adjuvant for use in simultaneous polishing of a cationically charged material and an anionically charged material, which forms an adsorption layer on the cationically charged material in order to increase polishing selectivity of the anionically charged material, wherein the adjuvant comprises a polyelectrolyte salt containing: (a) a mixture of an anionically charged linear polyelectrolyte having a weight average molecular weight of 2,000˜50,000 with an anionically charged graft type polyelectrolyte that has a weight average molecular weight of 1,000˜20,000 and comprises a backbone and a side chain; and (b) a basic material, wherein the side chain comprises a macrounit derived from a polymerization or a copolymerization of ethyleneically unsaturated monomers containing at least one functional group selected from a hydroxyl group, a carboxyl group and a sulfonic acid group and has a length corresponding to a molecular weight of 500˜2,000; and the backbone comprises a unit derived from methacrylic acid or acrylic acid in an amount of 65 to 100 parts by weight, based on the total weight of the backbone and has a length corresponding to a molecular weight of 500˜15,000.