Composition and method for polishing bulk silicon
View Patent ↗The invention provides a polishing composition comprising (a) silica, (b) one or more compounds that increases the removal rate of silicon, (c) one or more tetraalkylammonium salts, and (d) water, wherein the polishing composition has a pH of about 7 to about 11. The invention further provides a method of polishing a substrate with the polishing composition.
1. A chemical-mechanical polishing composition consisting essentially of:
(a) about 0.5 wt. % to about 20 wt. % of silica,
(b) about 0.02 wt. % to about 5 wt. % of one or more organic carboxylic acids,
(c) about 0.05 wt. % to about 2 wt. % of one or more aminophosphonic acids,
(d) about 0.1 wt. % to about 5 wt. % of one or more tetraalkylammonium salts selected from the group consisting of tetraalkylammonium hydroxide, chloride, bromide, sulfate, and hydrogensulfate salts,
(e) potassium bicarbonate,
(f) optionally potassium hydroxide, and
(g) water,
wherein the polishing composition has a pH of about 8 to about 11.
2. The polishing composition of claim 1 , wherein the silica is present in the polishing composition in an amount of from about 5 wt. % to about 20 wt% .
3. The polishing composition of claim 2 , wherein the silica is present in the polishing composition in an amount of from about 10 wt. % to about 15 wt. %.
4. The polishing composition of claim 1 , wherein the silica is wet-process silica.
5. The polishing composition of claim 1 , wherein the organic carboxylic acid is present in the polishing composition in an amount of from about 0.1 wt. % to about 2 wt. %.
6. The polishing composition of claim 1 , wherein at least one organic carboxylic acid is a hydroxycarboxylic acid.
7. The polishing composition of claim 6 , wherein the organic carboxylic acid is an aliphatic hydroxycarboxylic acid.
8. The polishing composition of claim 7 , wherein the organic carboxylic acid is selected from the group consisting of lactic acid, 2-hydroxybutyric acid, benzilic acid, and combinations thereof.
9. The polishing composition of claim 1 , wherein at least one organic carboxylic acid is a hydroxybenzoic acid.
10. The polishing composition of claim 9 , wherein the organic carboxylic acid is selected from the group consisting of salicylic acid, 2,6-dihydroxybenzoic acid, and combinations thereof.
11. The polishing composition of claim 9 , wherein the organic carboxylic acid is an amino hydroxybenzoic acid.
12. The polishing composition of claim 1 , wherein at least one carboxylic acid is an amino acid.
13. The polishing composition of claim 12 , wherein the amino acid is selected from the group consisting of proline, glycine, alanine, and combinations thereof.
14. The polishing composition of claim 1 , wherein the at least one aminophosphonic acid is present in the polishing composition in an amount of from about 0.1 wt . % to about 1 wt. %.
15. The polishing composition of claim 14 , wherein the aminophosphonic acid is selected from the group consisting of ethylenediaminetetra(methylene phosphonic acid), amino tri(methylene phosphonic acid), diethylenetriaminepenta(methylene phosphonic acid), and combinations thereof.
16. The polishing composition of claim 15 , wherein the aminophophonic acid is amino tri(methylene phosphonic acid).
17. The polishing composition of claim 1 , wherein potassium hydroxide is present in the polishing composition.
18. The polishing composition of claim 1 , wherein the polishing composition has a pH of about 8 to about 10.