Patent ID: 7033942

Claim:
A method of chemically mechanically polishing a substrate, said method comprising: providing a semiconductor wafer substrate comprising a surface having a metal to be polished; and contacting the surface with a polishing slurry comprising a first oxidizer and a second oxidizer, wherein the second oxidizer is different than the first oxidizer, and the slurry comprising the first and second oxidizers exhibits a synergistically increased metal removal rate, wherein: the first oxidizer is selected from the group consisting of ammonium persulfate, hydroxylamine nitrate, periodic acid, hydrogen peroxide, an indirect source of hydrogen peroxide, a urea hydrogen peroxide complex, or a percarbonate; the second oxidizer is selected from the group consisting of a peroxymonosulfate compound, hydroxylamine, potassium periodate, an IO 3 − salt, an IO 4 − salt, an H 4 IO 6 −2 salt, potassium iodate, or periodic acid, and wherein the second oxidizer is not a product of the reaction of the first oxidizer with any component in the slurry nor with any component of the substrate.