Patent ID: 8715524

Claim:
A polishing liquid for polishing a barrier layer of a semiconductor integrated circuit, the polishing liquid comprising: a diquaternary ammonium cation; a corrosion inhibiting agent which is benzotriazole or a derivative thereof; and a colloidal silica, wherein the pH of the polishing liquid is in the range of 2.5 to 5.0, wherein the diquaternary ammonium cation is a cation introduced from a compound represented by Formula (1) below, wherein, in Formula (1): R 1 to R 6 each independently represent an alkyl group having 1 or 2 carbon atoms; X represents an alkylene group having 5 or 6 carbon atoms; and nA m− represents a counter anion, wherein n and m each independently represent an integer of 1 or 2, and wherein when n is 1, m is 2, and when n is 2, m is 1, wherein the counter anion represented by nA m− is selected from the group consisting of a nitrate ion, a citrate ion, a phosphate ion, an oxalate ion, a phthalate ion, a maleate ion, a fumarate ion, a tartrate ion, a malate ion, a glycolate ion, a hydroxide ion, an acetate ion, a lactate ion, a sulfate ion, a silicate ion, a p-toluenesulfonate ion, a benzenesulfonate ion, a methanesulfonate ion, an ethanesulfonate ion, a diglycolate ion, a 2,5-furandicarboxylate ion, a 2-tetrahydrofurancarboxylate ion, a chloride ion, and a borate ion, wherein the cation is (A-2) or (A-9): and wherein the amount of the compound represented by Formula (1) is 0.0001 mass % to 1 mass % with respect to the total amount of the polishing liquid.