Neutral to alkaline chemical mechanical polishing compositions and methods for tungsten
View Patent ↗A neutral to alkaline chemical mechanical composition for polishing tungsten includes, as initial components: water; an oxidizing agent selected from an iodate compound, a periodate compound and mixtures thereof; colloidal silica abrasive particles including a nitrogen-containing compound; optionally, a pH adjusting agent; and, optionally, a biocide. The chemical mechanical polishing method includes 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 neutral to alkaline chemical mechanical 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 and, further, to at least inhibit static etch of the tungsten.
1. A chemical mechanical polishing composition for tungsten consisting of, as initial components: water; an oxidizing agent selected from the group consisting of potassium iodate, sodium iodate, potassium periodate, sodium periodate and mixtures thereof, wherein the oxidizing agent is in amounts of 0.001 wt % to 1 wt %;
colloidal silica abrasive particles comprising a nitrogen-containing compound selected from the group consisting of aminosilane, a nitrogen-containing compound having an amino group, tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, tetrapentylammonium, ethyltrimethylammonium, diethylmethylammonium and mixtures thereof, and a net negative zeta potential;
a pH adjusting agent; and,
a biocide; and wherein a pH of the chemical mechanical polishing composition is equal to or greater than 7.
2. The chemical mechanical polishing composition of claim 1 , wherein the oxidizing agent is selected from the group consisting of potassium iodate, potassium periodate and mixtures thereof.
3. The chemical mechanical polishing composition of claim 1 , wherein the nitrogen-containing compound is an aminosilane, wherein a molar ratio of the aminosilane to the colloidal silica abrasive particles is greater than 0.1% to less than 10%.
4. The chemical mechanical polishing compositions of claim 1 , wherein the oxidizing agent is in amounts of 0.1 wt % to 1 wt %.
5. The chemical mechanical polishing composition of claim 4 , wherein the oxidizing agent is in amounts of 0.3 wt % to 0.5 wt %.
6. The chemical mechanical polishing composition of claim 1 , wherein the pH is 7-13.
7. The chemical mechanical polishing composition of claim 6 , wherein the pH is 8-12.
8. The chemical mechanical polishing composition of claim 7 , wherein the pH is 8-10.