Patent ID: 10815392

Abstract:
A process for chemical mechanical polishing a substrate containing tungsten is disclosed to reduce corrosion rate and inhibit dishing of the tungsten and erosion of underlying dielectrics. The process includes providing a substrate; providing a polishing composition, containing, as initial components: water; an oxidizing agent; nonionic polyacrylamide; a dicarboxylic acid, a source of iron ions; a colloidal silica abrasive having a negative zeta potential; and, optionally, a pH adjusting agent; 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 tungsten is polished away from the substrate, corrosion rate is reduced, dishing of the tungsten is inhibited as well as erosion of dielectrics underlying the tungsten.