Patent ID: 11339308

Abstract:
A process for chemical mechanical polishing a substrate containing tungsten and titanium is provided comprising: providing the substrate; providing a polishing composition, containing, as initial components: water; an oxidizing agent; a chitosan; a dicarboxylic acid, wherein the dicarboxylic acid is selected from the group consisting of propanedioic acid and 2-hydroxypropanedioic acid; a source of iron ions; a colloidal silica abrasive with a positive surface charge; and, optionally 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 (W) and some of the titanium (Ti) is polished away from the substrate with a removal selectivity for the tungsten (W) relative to the titanium (Ti).