Patent ID: 8541310

Claim:
A chemical-mechanical polishing (CMP) method for polishing a ruthenium-containing substrate in the presence of hydrogen peroxide without forming a toxic level of ruthenium tetroxide, comprising the steps of: (a) contacting a surface of the ruthenium-containing substrate with a polishing pad and an aqueous CMP composition in the presence of hydrogen peroxide; and (b) causing relative motion between the polishing pad and the substrate while maintaining a portion of the CMP composition and hydrogen peroxide in contact with the surface between the pad and the substrate for a time period sufficient to abrade at least a portion of the ruthenium present in the substrate from the surface; wherein the CMP composition comprises (i) a catalytic oxidant comprising a water-soluble peroxometalate complex and an oxidizable precursor of a peroxometalate complex, the peroxometalate complex and the precursor thereof each having a reduced form that is oxidizable by hydrogen peroxide to generate the peroxometalate complex during chemical-mechanical polishing, wherein the water soluble peroxometalate complex is selected from the group consisting of an isoperoxotungstate compound, a peroxotitanate compound and a titanium hydroperoxosilicate compound, and wherein the oxidizable precursor of the peroxometalate complex is selected from the group consisting of an acidic tungsten-containing compound and a titanate compound; (ii) a particulate abrasive; and (iii) an aqueous carrier.