CMP compositions selective for oxide over polysilicon and nitride with high removal rate and low defectivity
View Patent ↗The invention provides a chemical-mechanical polishing composition containing a ceria abrasive and a polymer of formula I: wherein X 1 and X 2 , Y 1 and Y 2 , Z 1 and Z 2 , R 1 , R 2 , R 3 , and R 4 , and m are as defined herein, and water, wherein the polishing composition has a pH of about 1 to about 4.5. The invention further provides a method of chemically-mechanically polishing a substrate with the inventive chemical-mechanical polishing composition. Typically, the substrate contains silicon oxide, silicon nitride, and/or polysilicon.
1. A chemical-mechanical polishing composition comprising:
(a) about 0.05 wt. % to about 10 wt. % of a ceria abrasive,
(b) about 10 ppm to about 1000 ppm of a polymer of formula I:
wherein X 1 and X 2 are independently selected from O, C, and S,
Y 1 and Y 2 are independently selected from OH, C 1 -C 10 alkyl, and a group of the formula: C x H y F z ,
R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, F, C 1 -C 10 alkyl, C 6 -C 10 aryl, and heteroaromatic,
x is an integer of 1 to about 20,
z is an integer of 1 to about 41,
m is an integer of about 3 to about 500, and
at least one of Y 1 or Y 2 is C x H y F z or at least one of R 1 -R 4 is F, and
(c) water,
wherein the polishing composition has a pH of about 1 to about 4.5.
2. The polishing composition of claim 1 , wherein each of Y 1 and Y 2 is C x H y F z .
3. The polishing composition of claim 1 , wherein each of X 1 and X 2 is O.
4. The polishing composition of claim 1 , wherein each of R 1 , R 2 , R 3 , and R 4 is independently hydrogen or F.
5. The polishing composition of claim 1 , wherein x is an integer of 1 to 9.
6. The polishing composition of claim 1 , wherein x is an integer of 1 to 8 and y is an integer of 1 to 40.
7. The polishing composition of claim 1 , wherein the polymer has a molecular weight of about 500 daltons to about 10,000 daltons, and wherein m is an integer with a value of 8 or greater.
8. The polishing composition of claim 1 , wherein the polishing composition further comprises an ionic polymer selected from (a) an ionic polymer of formula II:
wherein X 1 and X 2 are independently selected from hydrogen, —OH, and —COOH, and at least one of X 1 and X 2 is —COOH,
Z 1 and Z 2 are independently O or S,
R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, C 1 -C 6 alkyl, and C 7 -C 10 aryl, and
n is an integer of about 3 to about 500, and
(b) a polyacrylate.
9. The polishing composition of claim 1 , wherein the polishing composition further comprises a polyvinyl alcohol.
10. 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 0.05 wt. % to about 10 wt. % of a ceria abrasive,
(b) about 10 ppm to about 1000 ppm of a polymer of formula I:
wherein X 1 and X 2 are independently selected from O, C, and S,
Y 1 and Y 2 are independently selected from OH, C 1 -C 10 alkyl, and a group of the formula: C x H y F z ,
R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, F, C 1 -C 10 alkyl, C 6 -C 10 aryl, and heteroaromatic,
x is an integer of 1 to about 20,
z is an integer of 1 to about 41,
m is an integer of about 3 to about 500, and
at least one of Y 1 or Y 2 is C x H y F z or at least one of R 1 -R 4 is F, and
(c) water,
wherein the polishing composition has a pH of about 1 to about 4.5,
(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.
11. The method of claim 10 , wherein each of Y 1 and Y 2 is C x H y F z .
12. The method of claim 10 , wherein each of X 1 and X 2 is O.
13. The method of claim 10 , wherein each of R 1 , R 2 , R 3 , and R 4 is independently hydrogen or F.
14. The method of claim 10 , wherein x is an integer of 1 to 9.
15. The method of claim 10 , wherein x is an integer of 1 to 8 and y is an integer of 1 to 40.
16. The method of claim 10 , wherein the polymer has a molecular weight of about 500 daltons to about 10,000 daltons, and wherein m is an integer with a value of 8 or greater.
17. The method of claim 10 , wherein the polishing composition further comprises an ionic polymer selected from (a) an ionic polymer of formula II:
wherein X 1 and X 2 are independently selected from hydrogen, —OH, and —COOH, and at least one of X 1 and X 2 is —COOH,
Z 1 and Z 2 are independently O or S,
R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, C 1 -C 6 alkyl, and C 7 -C 10 aryl, and
n is an integer of about 3 to about 500, and
(b) a polyacrylate.
18. The method of claim 10 , wherein the polishing composition further comprises a polyvinyl alcohol.
19. The method of claim 10 , wherein the substrate comprises silicon oxide, and wherein at least a portion of the silicon oxide is abraded to polish the substrate.
20. The method of claim 19 , wherein the substrate further comprises silicon nitride, and wherein at least a portion of the silicon nitride is abraded to polish the substrate.
21. The method of claim 19 , wherein the substrate further comprises polysilicon, and wherein at least a portion of the polysilicon is abraded to polish the substrate.