Polypyrrolidone polishing composition and method

1. A polishing composition comprising:

(a) 0.01 wt. % to 0.1 wt. % of a pyrrolidone polymer;

(b) 0.05 wt. % to 2 wt. % of an aminophosphonic acid;

(c) 0.01 wt. % to 5 wt. % of a tetraalkylammonium salt; and

(d) water,

wherein the composition has a pH of about 7 to about 11.7.

2. The polishing composition of claim 1 further comprising 0.05 wt. % to 2 wt. % of a rate accelerator.

3. The polishing composition of claim 1 further comprising 0.01 wt % to 40 wt % of a silica particle.

4. The polishing composition of claim 1 , wherein the composition does not contain an abrasive.

5. The polishing composition of claim 1 , wherein the composition does not contain an oxidizer of silicon.

6. A polishing composition consisting essentially of:

(a) 0.01 wt. % to 0.1 wt. % of a pyrrolidone polymer;

(b) 0.05 wt. % to 2 wt. % of an aminophosphonic acid;

(c) 0.01 wt. % to 5 wt. % of a tetraalkylammonium salt;

(d) optionally, 0.05 wt. % to 2 wt. % of a rate accelerator;

(e) optionally, a pH adjustor;

(f) optionally, a bicarbonate salt; and

(g) water,

wherein the composition has a pH of about 7 to about 11.7.

7. The polishing composition of claim 6 , wherein the rate accelerator comprises a hydroxamic acid.

8. The polishing composition of claim 7 , wherein the rate accelerator comprises an acetohydroxamic acid.

9. The polishing composition of claim 6 , wherein the rate accelerator comprises a nitrogen containing heterocyclic compound.

10. The polishing composition of claim 9 , wherein the nitrogen containing heterocyclic compound comprises a triazole.

11. The polishing composition of claim 6 , wherein the pyrrolidone polymer comprises polyvinylpyrrolidone.

12. The polishing composition of claim 6 , wherein the pyrrolidone polymer comprises poly(1-vinylpyrrolidone-co-2-dimethylamino-ethyl methacrylate).

13. The polishing composition of claim 6 , wherein the aminophosphonic acid comprises aminotrimethylene phosphonic acid.

14. The polishing composition of claim 6 , wherein the tetraalkylammonium salt comprises tetramethyl ammonium hydroxide.

15. A method of polishing a substrate, which method comprises:

(i) contacting a substrate with a polishing pad and the polishing composition of claim 6 ;

(ii) moving the polishing pad relative to the substrate with the polishing composition therebetween; and

(iii) abrading at least a portion of the substrate to polish the substrate.

16. The method of claim 15 , wherein the substrate is a silicon wafer.