Compositions for etching polysilicon
Compositions for etching polysilicon including aqueous compositions containing nitric acid, ammonium fluoride, and poly-carboxylic acid.
1. An aqueous composition, comprising:
29.0-34.9 wt % water;
65-70 wt % nitric acid;
0.06-0.60 wt % ammonium fluoride; and
poly-carboxylic acid;
wherein the poly-carboxylic acid is present in the aqueous composition and the aqueous composition contains less than or equal to 0.4 wt % poly-carboxylic acid.
2. The aqueous composition of claim 1 , further comprising:
hydrofluoric acid;
wherein the hydrofluoric acid is present in the aqueous composition and the aqueous composition contains less than or equal to 0.08 wt % hydrofluoric acid.
3. The aqueous composition of claim 1 , wherein the aqueous composition comprises 29.4 to 34.9 wt % water.
4. The aqueous composition of claim 1 , wherein the aqueous composition comprises 69 wt % nitric acid, 0.6 wt % ammonium fluoride, and less than 30.4 wt % water.
5. The aqueous composition of claim 1 , wherein the poly-carboxylic acid is oxalic acid.
6. An aqueous composition comprising 69 wt % nitric acid, 0.6 wt % ammonium fluoride, 0.4 wt % poly-carboxylic acid, and 30 wt % water.
7. A composition for etching polysilicon, consisting essentially of:
nitric acid;
ammonium fluoride;
poly-carboxylic acid; and
water;
wherein the composition contains 65-70 wt % nitric acid.
8. The composition of claim 7 , wherein the composition contains 28.9-34.9 wt % water.
9. The composition of claim 7 , wherein the composition contains 0.06-0.60 wt % ammonium fluoride.
10. The composition of claim 9 , wherein the composition contains less than or equal to 0.4 wt % poly-carboxylic acid.
11. The composition of claim 7 , further comprising at least one component selected from a group consisting of a dye, a lubricant, a stabilizer, a buffer, a surfactant, a thickening agent, a preservative and an antimicrobial agent.
12. A composition for etching polysilicon, consisting essentially of:
nitric acid;
ammonium fluoride;
water;
hydrofluoric acid; and
poly-carboxylic acid;
wherein the composition contains 65-70 wt % nitric acid.
13. The composition of claim 12 , wherein the composition contains 0.06-0.60 wt % ammonium fluoride and less than or equal to 0.08 wt % hydrofluoric acid.
14. The composition of claim 12 , wherein the composition contains 0.06-0.60 wt % ammonium fluoride and less than or equal to 0.4 wt % poly-carboxylic acid.
15. The composition of claim 14 , wherein the poly-carboxylic acid is oxalic acid.
16. The composition of claim 13 , wherein the composition contains 0.06-0.60 wt % ammonium fluoride, less than or equal to 0.08 wt % hydrofluoric acid and less than or equal to 0.4 wt % poly-carboxylic acid.
17. The composition of claim 16 , wherein the poly-carboxylic acid is oxalic acid.
18. The composition of claim 12 , further comprising at least one component selected from a group consisting of a dye, a lubricant, a stabilizer, a buffer, a surfactant, a thickening agent, a preservative and an antimicrobial agent.
19. An aqueous composition, comprising:
28.9-34.9 wt % water;
65-70 wt % nitric acid;
0.06-0.60 wt % ammonium fluoride;
hydrofluoric acid; and
oxalic acid;
wherein the hydrofluoric acid is present in the aqueous composition and the aqueous composition contains less than or equal to 0.08 wt % hydrofluoric acid; and
wherein the oxalic acid is present in the aqueous composition and the aqueous composition contains less than or equal to 0.4 wt % oxalic acid.