CMP POLISHING SOLUTION

摘要

PROBLEM TO BE SOLVED: To provide a CMP(chemical mechanical polishing) solution in which its pH variations are small, the polishing speed ratio of silicon oxide to silicon nitride can be increased, the flatness of the polished surface can be improved (projections on the polished surface of a silicon oxide insulating film can be selectively polished), and the polishing speed variations are small. SOLUTION: This CMP solution exhibits pH variations of 0.2 or less at 25 deg.C. Preferably, the CMP solution is prepared by adding a pH buffer agent, 123-morpholinopropanesulfonate, and tetramethylammonium hydroxide to a slurry (pH 7.45) composed of oxide cerium as abrasive grains, an acrylate-methyl acrylate copolymerized ammonium salt as a sticking agent and water. The pH of the CMP solution thus prepared is adjusted to 7.35, and the solution thus adjusted is left intact for 2 months at 25 deg.C to have its pH further adjusted to 7.33.