Selective nitride slurries with improved stability and improved polishing characteristics
View Patent ↗The invention provides a chemical-mechanical polishing composition comprising, consisting essentially of, or consisting of (a) about 0.01 wt. % to about 1 wt. % of wet-process ceria, (b) about 10 ppm to about 200 ppm of a cationic polymer comprising quaternary amino groups, (c) about 10 ppm to about 2000 ppm of a non-fluorinated nonionic surfactant, (d) an amino acid, and (e) water, wherein the polishing composition has a pH of about 3 to about 8. The invention further provides a method of polishing a substrate with the polishing composition.
1. A chemical-mechanical polishing composition comprising:
(a) about 0.01 wt. % to about 1 wt. % of wet-process ceria,
(b) about 10 ppm to about 200 ppm of a cationic polymer comprising quaternary amino groups,
(c) about 10 ppm to about 2000 ppm of a non-fluorinated nonionic surfactant,
(d) an amino acid, and
(e) water,
wherein the polishing composition has a pH of about 3 to about 8.
2. The polishing composition of claim 1 , wherein the wet-process ceria comprises a mixture of a first ceria having an average particle size of about 10 nm to about 60 nm and a second ceria having an average particle size of about 60 nm to about 150 nm.
3. The polishing composition of claim 1 , wherein the cationic polymer comprises diallyl dimethyl ammonium monomer units.
4. The polishing composition of claim 1 , wherein the cationic polymer comprises methacryloxyethyltrimethylammonium monomer units, N,N-dimethyl-2-hydroxypropylammonium monomer units, (3-methyl-1-vinylimidazolium chloride) units, quaternized [bis(2-chloroethyl) ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] units, quaternized anhydroglucose units, or a combination thereof.
5. The polishing composition of claim 1 , wherein the non-fluorinated nonionic surfactant is a polyoxyethylene-polyoxypropylene block copolymer, or a polyethylene glycol alkyl ether.
6. The polishing composition of claim 5 , wherein the non-fluorinated nonionic surfactant has an average molecular weight from about 500 Daltons to about 2000 Daltons.
7. The polishing composition of claim 1 , wherein the amino acid is glycine, alanine, or valine, or a combination thereof.
8. The polishing composition of claim 1 , wherein the polishing composition further comprises a fluorinated nonionic surfactant.
9. The polishing composition of claim 1 , wherein the polishing composition further comprises about 1 ppm to about 500 ppm of a polyvinyl alcohol.
10. The polishing composition of claim 1 , wherein the polishing composition has a pH from about 4 to about 7.
11. A method of chemically mechanically polishing a substrate comprising:
(i) contacting a substrate with a polishing pad and a chemical-mechanical polishing composition comprising:
(a) about 0.01 wt. % to about 1 wt. % of wet-process ceria,
(b) about 10 ppm to about 200 ppm of a cationic polymer comprising quaternary amino groups,
(c) about 10 ppm to about 2000 ppm of a non-fluorinated nonionic surfactant,
(d) an amino acid, and
(e) water,
wherein the polishing composition has a pH of about 3 to about 8,
(ii) moving the polishing pad and the chemical mechanical polishing composition relative to the substrate, and
(iii) abrading at least a portion of the substrate to polish the substrate.
12. The method of claim 11 , wherein the wet-process ceria comprises a mixture of a first ceria having an average particle size of about 10 nm to about 60 nm and a second ceria having an average particle size of about 60 nm to about 150 nm.
13. The method of claim 11 , wherein the cationic polymer comprises diallyl dimethyl ammonium monomer units.
14. The method of claim 11 , wherein the cationic polymer comprises methacryloxyethyltrimethylammonium monomer units, N,N-dimethyl-2-hydroxypropylammonium monomer units, (3-methyl-1-vinylimidazolium chloride) units, quaternized [bis(2-chloroethyl) ether-alt-1,3-bis[3-(dimethylamino)propyl]urea]units, quaternized anhydroglucose units.
15. The method of claim 11 , wherein the non-fluorinated nonionic surfactant is a polyoxyethylene-polyoxypropylene block copolymer, or a polyethylene glycol alkyl ether.
16. The method of claim 15 , wherein the non-fluorinated nonionic surfactant has an average molecular weight from about 500 Daltons to about 2000 Daltons.
17. The method of claim 11 , wherein the amino acid is glycine, alanine, or valine, or a combination thereof.
18. The method of claim 11 , wherein the polishing composition further comprises a fluorinated nonionic surfactant.
19. The polishing composition of claim 11 , wherein the polishing composition further comprises about 1 ppm to about 500 ppm of a polyvinyl alcohol.
20. The method of claim 11 , wherein the polishing composition has a pH from about 4 to about 7.
21. The method of claim 11 , wherein the substrate comprises silicon nitride, and wherein at least a portion of the silicon nitride is abraded to polish the substrate.
22. The method of claim 21 , wherein the substrate further comprises silicon oxide, and wherein at least a portion of the silicon oxide is abraded to polish the substrate.
23. The method of claim 22 , wherein the substrate further comprises polysilicon, and wherein at least a portion of the polysilicon is abraded to polish the substrate.