Patent ID: 8865013

Claim:
A method for chemical mechanical polishing of a substrate, comprising: providing a substrate, wherein the substrate comprises tungsten; providing a chemical mechanical polishing slurry composition comprising, as initial components: water; 0.1 to 5 wt % of an abrasive; 0.005 to 0.1 wt % of a diquaternary compound according to formula (I): wherein each A is independently selected from N and P; wherein R 1 is selected from a saturated or unsaturated C 1 -C 15 alkyl group, a C 6 -C 15 aryl group and a C 6 -C 15 aralkyl group; wherein R 2 , R 3 , R 4 , R 5 , R 6 and R 7 are each independently selected from selected from a hydrogen, a saturated or unsaturated C 1 -C 15 alkyl group, a C 6 -C 15 aryl group, a C 6 -C 15 aralkyl group and a C 6 -C 15 alkaryl group; and, wherein the anion in formula (I) can be any anion or combination of anions that balance the 2+ charge on the cation in formula (I); 0.001 to 10 wt % of at least one of a phthalic acid, a phthalic anhydride, a phthalate compound and a phthalic acid derivative; 0.001 to 10 wt % potassium iodate; and, optionally, an acid, wherein the acid is selected from the group consisting of nitric acid, sulfuric acid and hydrochloric acid; wherein the chemical mechanical polishing composition provided has a pH of 1 to 4; wherein the chemical mechanical polishing composition exhibits a tungsten static etch rate of ≦5 Å/min and a tungsten removal rate of ≧100 Å/min; wherein the chemical mechanical polishing composition contains <0.001 wt % per-oxy oxidizer; and, wherein the chemical mechanical polishing composition does not contain corrosion inhibitor agent; providing a chemical mechanical polishing pad with a polishing surface; creating dynamic contact at an interface between the polishing surface of the chemical mechanical polishing pad and the substrate with a down force of 0.69 to 34.5 kPa; and dispensing the chemical mechanical polishing slurry composition onto the chemical mechanical polishing pad at or near the interface between the chemical mechanical polishing pad and the substrate; wherein the substrate is polished; and, wherein some of the tungsten is removed from the substrate.