Patent ID: 8609541

Claim:
A polishing method, characterized by including: a step of preparing a substrate having an interlayer dielectric having a surface comprising concave regions and convex regions, a barrier layer for covering the interlayer dielectric along the surface thereof, and an electroconductive material layer filled into the concave regions so as to cover the barrier layer; a first polishing step of polishing the electroconductive material layer of the substrate, thereby making the barrier layer over the convex regions exposed; and a second polishing step of exposing the interlayer dielectric over the convex regions by polishing the barrier layer exposed in the first polishing step by using a polishing slurry for metal films, the second polishing step comprising an over-polishing step of polishing the interlayer dielectric, wherein the polishing slurry for metal films comprises abrasive grains, a water-soluble polymer containing a methacrylic acid based polymer, an organic solvent and water, and the methacrylic acid based polymer has a ratio of the amount of methacrylic acid to the total amount of the monomers being 70% or more and less than 100% by mole.