Patent ID: 7294576

Claim:
A method of chemically-mechanically polishing a substrate, which method comprises: (a) providing a substrate with at least a first layer and a second layer, wherein the first layer and the second layer have not been contacted with a chemical-mechanical polishing composition, (b) preparing a final chemical-mechanical polishing composition comprising the steps of: (i) providing a first chemical-mechanical polishing composition comprising an abrasive with a first selectivity for a first layer as compared to a second layer, (ii) providing a second chemical-mechanical polishing composition comprising an abrasive with a second selectivity for the first layer as compared to the second layer, wherein the second chemical-mechanical polishing composition is stable in the presence of the first chemical-mechanical polishing composition, and wherein the first and second selectivities are different, and (iii) mixing the first and second chemical-mechanical polishing compositions in a ratio to achieve a final chemical-mechanical polishing composition with a final selectivity for the first layer as compared to the second layer, (c) contacting the substrate with the final chemical-mechanical polishing composition, (d) moving the polishing pad relative to the substrate with the final chemical-mechanical polishing composition therebetween, and (e) abrading at least a portion of the first and second layers of the substrate to polish the substrate.