Patent ID: 7319072

Claim:
A method of polishing a substrate member, comprising a step of polishing a barrier layer containing tantalum, a tantalum alloy or a tantalum compound by the use of a polishing medium for chemical-mechanical polishing, said polishing medium including: an oxidizing agent; a protective-film-forming agent; an acid; and water, wherein: said polishing medium does not include abrasive grains, said polishing medium has a pH of 3 or less, and said oxidizing agent is in a concentration of from 0.01% by weight to 3% by weight, and wherein: the polishing medium for chemical-mechanical polishing has, under polishing conditions of a polishing pressure of 25 kPa and relative speed of substrate member to polishing platen of 18 m/minute: a polishing-rate ratio (Ta/Cu) between tantalum and copper or a copper alloy of more than 1; a polishing-rate ratio (TaN/Cu) between tantalum nitride and copper or a copper alloy of more than 1; a polishing-rate ratio (Ta/SiO 2 ) between tantalum and silicon dioxide of more than 10; and a polishing-rate ratio (TaN/SiO 2 ) between tantalum nitride and silicon dioxide of more than 10; and the polishing is performed in the absence of abrasive.