Polishing composition for a tungsten-containing substrate
View Patent ↗The invention provides a method of chemically-mechanically polishing a substrate comprising tungsten through use of a composition comprising a tungsten etchant, an inhibitor of tungsten etching, and water, wherein the inhibitor of tungsten polishing is a polymer, copolymer, or polymer blend comprising at least one repeating group comprising at least one nitrogen-containing heterocyclic ring or a tertiary or quaternary nitrogen atom. The invention further provides a chemical-mechanical polishing composition particularly useful in polishing tungsten-containing substrates.
1. A chemical-mechanical polishing composition comprising:
(a) 0.0002 M to 0.4 M ferric ion,
(b) 1 ppm to 400 ppm poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride or poly[2-(methacryloyloxy)ethyl]trimethylammonium bromide,
(c) silica,
(d) malonic acid,
(e) water, and
(f) 0.1 wt. % to 10 wt. % of hydrogen peroxide,
wherein the polishing composition has a pH of 1 to 4.
2. The chemical-mechanical polishing composition of claim 1 , wherein the polishing composition further comprises an amino acid.
3. The chemical-mechanical polishing composition of claim 2 , wherein the amino acid is glycine.
4. The chemical-mechanical polishing composition of claim 1 , wherein ferric ion is present in a concentration of 0.0002 M to 0.04 M.
5. The chemical-mechanical polishing composition of claim 1 , wherein the polishing composition comprises:
(a) 0.0002 M to 0.04 M of ferric ion,
(b) 1 ppm to 400 ppm of poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride,
(c) silica,
(d) malonic acid, wherein malonic acid is present in an amount of 1 to 5 molar equivalents based on the amount of ferric ion,
(e) water, and
(f) 0.1 wt. % to 10 wt. % of hydrogen peroxide.
6. The chemical-mechanical polishing composition of claim 5 , wherein poly[2(methacryloyloxy)ethyl]trimethylammonium chloride is present in an amount of 50 ppm to 400 ppm.
7. The chemical-mechanical polishing composition of claim 6 , wherein silica is present in an amount of 0.2 wt. % to 3 wt. %.
8. The chemical-mechanical polishing composition of claim 5 , wherein the polishing composition further comprises an amino acid.
9. The chemical-mechanical polishing composition of claim 8 , wherein the amino acid is glycine.
10. The chemical-mechanical polishing composition of claim 1 , wherein the polishing composition comprises 1 ppm to 400 ppm poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride.
11. The chemical-mechanical polishing composition of claim 1 , wherein malonic acid is present in an amount of 1 to 5 molar equivalents based on the amount of ferric ion.
12. The chemical-mechanical polishing composition of claim 11 , wherein poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride or poly[2-(methacryloyloxy)ethyl]trimethylammonium bromide is present in an amount of 50 ppm to 400 ppm.
13. The chemical-mechanical polishing composition of claim 12 , wherein silica is present in an amount of 0.2 wt. % to 3 wt. %.