Polishing composition containing ceria particles and method of use
The invention provides a chemical-mechanical polishing composition including wet-process ceria particles having a median particle size of about 25 nm to about 150 nm and a particle size distribution of about 300 nm or more, and an aqueous carrier. The invention also provides a method of polishing a substrate, especially a substrate comprising a silicon layer, with the polishing composition.
1. A chemical-mechanical polishing composition comprising:
(a) wet-process ceria particles having a median particle size of about 25 nm to about 150 nm and a particle size distribution of about 300 nm or more, wherein the wet-process ceria particles have a surface that comprises tridentate hydroxyl groups and has a surface coverage of tridentate hydroxyl groups that is about 2.0×10 −5 moles/m 2 or more, and
(b) an aqueous carrier.
2. The chemical-mechanical polishing composition of claim 1 , wherein the wet-process ceria particles have a median particle size of about 40 nm to about 100 nm.
3. The chemical-mechanical polishing composition of claim 1 , wherein the wet-process ceria particles have a median particle size of about 60 nm to about 80 nm.
4. The chemical-mechanical polishing composition of claim 1 , wherein the wet-process ceria particles have a particle size distribution of about 350 nm or more.
5. The chemical-mechanical polishing composition of claim 4 , wherein the wet-process ceria particles have a particle size distribution of about 375 nm or more.
6. The chemical-mechanical polishing composition of claim 1 , wherein the wet-process ceria particles have a surface coverage of tridentate hydroxyl groups that is about 2.0×10 −5 moles/m 2 and about 6.0×10 −5 moles/m 2 .
7. The chemical-mechanical polishing composition of claim 6 , wherein the wet-process ceria particles have a surface coverage of tridentate hydroxyl groups that is about 2.3×10 −5 moles/m 2 or more.
8. The chemical-mechanical polishing composition of claim 1 , wherein a Raman spectrum of the wet-process ceria particles comprises a peak at about 458 cm −1 and a peak at about 583 cm −1 , and wherein the ratio of the intensity of the peak at about 458 cm −1 to the intensity of the peak at about 583 cm −1 is about 100 or less.
9. The chemical-mechanical polishing composition of claim 8 , wherein the ratio of the intensity of the peak at about 458 cm −1 to the intensity of the peak at about 583 cm −1 is about 65 or less.
10. The chemical-mechanical polishing composition of claim 1 , wherein the wet-process ceria particles are present in the polishing composition at a concentration of about 0.1 wt. % to about 1 wt. %.
11. The chemical-mechanical polishing composition of claim 10 , wherein the wet-process ceria particles are present in the polishing composition at a concentration of about 0.2 wt. % to about 0.6 wt. %.
12. The chemical-mechanical polishing composition of claim 1 , further comprising a pH-adjusting agent.
13. The chemical-mechanical polishing composition of claim 12 , wherein the pH-adjusting agent is selected from an alkyl amine, an alcohol amine, a quaternary amine hydroxide, ammonia, and combinations thereof.
14. The chemical-mechanical polishing composition of claim 12 , wherein the pH-adjusting agent is triethanolamine.
15. The chemical-mechanical polishing composition of claim 1 , wherein the pH of the polishing composition is about 1 to about 6.
16. The chemical-mechanical polishing composition of claim 15 , wherein the pH of the polishing composition is about 3.5 to about 5.
17. A method of polishing a substrate comprising:
(i) providing a substrate;
(ii) providing a polishing pad;
(iii) providing the chemical-mechanical polishing composition of claim 1 ;
(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 the substrate to polish the substrate.
18. A method of polishing a substrate comprising:
(i) providing a substrate, wherein the substrate comprises a silicon layer;
(ii) providing a polishing pad;
(iii) providing the chemical-mechanical polishing composition of claim 1 ;
(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 the silicon layer on a surface of the substrate to polish the substrate.
19. The method of claim 18 , wherein the silicon layer is selected from a silicon oxide layer, a silicon nitride layer, a polysilicon layer, and combinations thereof.
20. The method of claim 18 , wherein the silicon layer is a tetraethoxysilane (TEOS) layer.