Planarization by chemical polishing for ULSI applications

Methods, compositions, and apparatus are provided for planarizing conductive materials disposed on a substrate surface by an chemical polishing technique. In one aspect, a substrate having conductive material disposed thereon is disposed on a substrate support and exposed to a composition containing an oxidizing agent and an inorganic etchant. The substrate is planarized by the composition without the presence of mechanical abrasion. The substrate may optionally be rotated, agitated, or both during exposure to the composition. The method removes conductive materials forming protuberances on the substrate surface at a higher rate than conductive materials forming recesses on the substrate surface.