Patent ID: 7744666

Claim:
A polishing medium having a property of chemical-mechanical polishing of a surface, and comprising: abrasive grains, an oxidizing agent for a conductor; a protective-film-forming agent for protecting a metal surface; an acid; and water, wherein: said abrasive grains have an average particle diameter of 50 nm or less and a standard deviation of particle size distribution in a value of more than 5 nm, said polishing medium has a pH of 3 or less, and said polishing medium has a property of chemical-mechanical polishing of a surface having at least one of tantalum, tantalum alloy and a tantalum compound which is on silicon dioxide and which is originally covered by copper or copper alloy, and is exposed after polishing of the copper or copper alloy, the polishing medium having a property of chemical-mechanical polishing said at least one of tantalum, tantalum alloy and a tantalum compound exposed after polishing of the copper or copper alloy, and chemical-mechanical polishing said at least one of tantalum, tantalum alloy and the tantalum compound at a higher polishing rate than a polishing rate of said silicon dioxide by said polishing medium.