Chemical mechanical polishing method for cobalt with high cobalt removal rates and reduced cobalt corrosion

Abstract

A process for chemical mechanical polishing cobalt to planarize the surface and remove at least some of the cobalt from a substrate. The process includes providing a polishing composition, containing, as initial components: water; an oxidizing agent; colloidal silica abrasive particles; aspartic acid or salts thereof; a phosphonic acid having an alkyl group of greater than ten carbon atoms, wherein the phosphonic acid having the alky group of greater than ten carbon atoms is included in amounts sufficient to enable high cobalt removal rates of ≥2000 Å/min and substantial cobalt corrosion inhibition; and providing a chemical mechanical polishing pad, having a polishing surface; creating dynamic contact at an interface between the polishing pad and the substrate; and dispensing the polishing composition onto the polishing surface at or near the interface between the polishing pad and the substrate; wherein some of the cobalt is polished away and cobalt corrosion is substantially inhibited.