Tungsten buff polishing compositions with improved topography
The invention provides a chemical-mechanical polishing composition comprising a) surface-modified colloidal silica particles, comprising a negatively-charged group on the surface of the particles, wherein the surface-modified colloidal silica particles have a negative charge, a particle size of about 90 nm to about 350 nm, and a zeta potential of about −5 mV to about −35 mV at a pH of about 3, b) an iron compound, c) a stabilizing agent, d) a corrosion inhibitor, and e) an aqueous carrier. The invention also provides a method suitable for polishing a substrate.
1. A chemical-mechanical polishing composition comprising:
(a) surface-modified colloidal silica particles comprising a negatively-charged group on the surface of the particles, wherein the surface-modified colloidal silica particles have
a negative charge,
a particle size of about 90 nm to about 350 nm, and
a zeta potential of about −5 mV to about −35 mV at a pH of about 3,
(b) an iron compound,
(c) a stabilizing agent,
(d) a corrosion inhibitor, and
(e) an aqueous carrier.
2. The polishing composition of claim 1 , wherein the negatively-charged group on the surface of the surface-modified colloidal silica particles comprises a sulfonate group, a carboxylate group, a phosphonate group, or combinations thereof.
3. The polishing composition of claim 1 , wherein the surface-modified colloidal silica particles have a particle size of about 90 nm to about 200 nm.
4. The polishing composition of claim 3 , wherein the surface-modified colloidal silica particles have a particle size of about 120 nm to about 180 nm.
5. The polishing composition of claim 1 , wherein the pH of the polishing composition is about 1.5 to about 4.
6. The polishing composition of claim 5 , wherein the pH of the polishing composition is about 2 to about 3.5.
7. The polishing composition of claim 1 , wherein the surface-modified colloidal silica particles are present in the polishing composition in a concentration of about 1.5 wt. % to about 3.5 wt. %.
8. The polishing composition of claim 7 , wherein the surface-modified colloidal silica particles are present in the polishing composition in a concentration of about 2 wt. % to about 3 wt. %.
9. The polishing composition of claim 1 , wherein the iron compound comprises ferric nitrate or a hydrate thereof.
10. The polishing composition of claim 1 , wherein the stabilizing agent comprises phosphoric acid, o-phosphoryl ethanolamine, alendronic acid, acetic acid, phthalic acid, citric acid, adipic acid, oxalic acid, malonic acid, aspartic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, glutaconic acid, muconic acid, ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, or combinations thereof.
11. The polishing composition of claim 10 , wherein the stabilizing agent comprises malonic acid.
12. The polishing composition of claim 10 , wherein the stabilizing agent is present in the polishing composition in a concentration of about 0.0001 wt. % to about 0.01 wt. %.
13. The polishing composition of claim 1 , wherein the corrosion inhibitor comprises glycine, alanine, lysine, arginine, histidine, or combinations thereof.
14. The polishing composition of claim 13 , wherein the corrosion inhibitor comprises alanine, glycine, lysine, or arginine.
15. The polishing composition of claim 14 , wherein the corrosion inhibitor comprises glycine.
16. The polishing composition of claim 13 , wherein the corrosion inhibitor is present in the polishing composition in a concentration of about 0.005 wt. % to about 1 wt. %.
17. The polishing composition of claim 16 , wherein the corrosion inhibitor is present in the polishing composition in a concentration of about 0.1 wt. % to about 0.5 wt. %.
18. A method of chemically-mechanically polishing a substrate comprising:
(i) providing a substrate;
(ii) providing a polishing pad;
(iii) providing a chemical-mechanical polishing composition comprising:
(a) surface-modified colloidal silica particles comprising a negatively-charged group on the surface of the particles, wherein the surface-modified colloidal silica particles have
a negative charge,
a particle size of about 90 nm to about 350 nm, and
a zeta potential of about −5 mV to about −35 mV at a of about 3,
(b) an iron compound,
(c) a stabilizing agent,
(d) a corrosion inhibitor, and
(e) an aqueous carrier;
(iv) contacting the substrate with the polishing pad and the chemical mechanical polishing composition; and
(v) moving the polishing pad and the chemical-mechanical polishing composition relative to the substrate to abrade at least a portion of a surface of the substrate to polish the substrate.
19. The method of claim 18 , wherein the negatively-charged group on the surface of the surface-modified colloidal silica particles comprises a sulfonate group, a carboxylate group, a phosphonate group, or combinations thereof.
20. The method of claim 18 , wherein the surface-modified colloidal silica particles have a particle size of about 90 nm to about 200 nm.
21. The method of claim 20 , wherein the surface-modified colloidal silica particles have a particle size of about 120 nm to about 180 nm.
22. The method of claim 18 , wherein the pH of the polishing composition is about 1.5 to about 4.
23. The polishing composition of claim 22 , wherein the of the pH of the polishing composition is about 2 to about 3.5.
24. The method of claim 18 , wherein the surface-modified colloidal silica particles are present in the polishing composition in a concentration of about 1.5 wt. % to about 3.5 wt. %.
25. The method of claim 24 , wherein the surface-modified colloidal silica particles are present in the polishing composition in a concentration of about 2 wt. % to about 3 wt. %.
26. The method of claim 18 , wherein the iron compound comprises ferric nitrate or a hydrate thereof.
27. The method of claim 18 , wherein the stabilizing agent comprises phosphoric acid, o-phosphorylethanolamine, alendronic acid, acetic acid, phthalic acid, citric acid, adipic acid, oxalic acid, malonic acid, aspartic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, glutaconic acid, muconic acid, ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, or combinations thereof.
28. The method of claim 27 , wherein the stabilizing agent comprises malonic acid.
29. The method of claim 27 , wherein the stabilizing agent is present in the polishing composition in a concentration of about 0.0001 wt. % to about 0.01 wt. %.
30. The method of claim 18 , wherein the corrosion inhibitor comprises glycine, alanine, lysine, arginine, histidine, or combinations thereof.
31. The method of claim 30 , wherein the corrosion inhibitor comprises alanine, glycine, lysine, or arginine.
32. The method of claim 31 , wherein the corrosion inhibitor comprises glycine.
33. The method of claim 30 , wherein the corrosion inhibitor is present in the polishing composition in a concentration of about 0.005 wt. % to about 1 wt. %.
34. The method of claim 33 , wherein the corrosion inhibitor is present in the polishing composition in a concentration of about 0.1 wt. % to about 0.5 wt. %.
35. The method of claim 18 , wherein the substrate comprises a tungsten layer on a surface of the substrate and a silicon oxide layer on a surface of the substrate, and wherein at least a portion of the tungsten layer and at least a portion of the silicon oxide layer are abraded to polish the substrate.
36. The method of claim 35 , wherein the abrasion of at least a portion of the tungsten layer provides a removal rate for tungsten, wherein the abrasion of at least a portion of the silicon oxide layer provides a removal rate for silicon oxide, and wherein the ratio of the tungsten removal rate to the silicon oxide removal rate is about 0.5:1 to about 2.75:1.