| abstract |
The invention provides a method of polishing a substrate comprising a noble metal comprising (i) contacting the substrate with a CMP system and (ii) abrading at least a portion of the substrate to polish the substrate. The CMP systems each comprise an abrasive and/or polishing pad, a liquid carrier, and optionally one or more polishing additives. In a first embodiment, the polishing additives are selected from the group consisting of diketones, diketonates, heterocyclic nitrogen-containing compounds, heterocyclic oxygen-containing compounds, heterocyclic phosphorus-containing compounds, urea compounds, nitrogen-containing compounds that can be zwitterionic compounds, salts thereof, and combinations thereof. In a second embodiment, the polishing additive is a metal compound with two or more oxidation states and is used in conjunction with a peroxy-type oxidizer. In a third embodiment, the CMP system comprises alpha-alumina and fumed alumina, wherein the weight ratio of alpha-alumina to fumed alumina is about 0.6:1 to about 9:1. |