Silicon carbide polishing method utilizing water-soluble oxidizers
View Patent ↗The inventive method comprises chemically-mechanically polishing a substrate comprising at least one layer of silicon carbide with a polishing composition comprising a liquid carrier, an abrasive, and an oxidizing agent.
1. A method of chemically-mechanically polishing a substrate, which method comprises:
(i) contacting a substrate comprising at least one layer of single crystal silicon carbide with a chemical-mechanical polishing composition comprising:
(a) a liquid carrier, wherein the liquid carrier with any components dissolved or suspended therein has a pH of about 5 or less,
(b) an abrasive suspended in the liquid carrier, wherein the abrasive consists of substantially spherical precipitated or condensation-polymerized silica particles having an average particle size of about 40 nm to about 130 nm, and
(c) an oxidizing agent selected from the group consisting of oxone, ammonium cerium nitrate, periodates, iodates, persulfates, and mixtures thereof,
(ii) moving the polishing composition relative to the substrate, and
(iii) abrading at least a portion of the silicon carbide of the substrate to polish the substrate.
2. The method of claim 1 , wherein the abrasive is present in an amount of about 5 wt. % to about 40 wt. % based on the weight of the liquid carrier and any components dissolved or suspended therein.
3. The method of claim 2 , wherein the abrasive is present in an amount of about 15 wt. % to about 35 wt. % based on the weight of the liquid carrier and any components dissolved or suspended therein.
4. The method of claim 3 , wherein the liquid carrier comprises water, and the liquid carrier with any components dissolved or suspended therein has a pH of about 3 or less.
5. The method of claim 4 , wherein the oxidizer is ammonium cerium nitrate.
6. The method of claim 5 , wherein the oxidizer is present in the amount of 0.05 wt. % to about 2 wt. %.
7. The method of claim 4 , wherein the oxidizer is potassium periodate.
8. The method of claim 7 , wherein the oxidizer is present in the amount of 0.05 wt. % to about 2 wt. %.
9. The method of claim 4 , wherein the oxidizer is potassium persulfate.
10. The method of claim 9 , wherein the oxidizer is present in the amount of 0.05 wt. % to about 2 wt. %.
11. The method of claim 1 , wherein the liquid carrier comprises water.
12. The method of claim 1 , wherein the substantially spherical silica is condensation-polymerized silica.
13. The method of claim 1 , wherein the oxidizing agent is present in an amount of about 0.01 wt. % to about 5 wt. % based on the weight of the liquid carrier and any components dissolved or suspended therein.
14. The method of claim 1 , wherein the oxidizing agent is potassium periodate or potassium iodate.
15. The method of claim 1 , wherein the oxidizer is potassium persulfate.
16. The method of claim 1 , wherein the silicon carbide is removed from the substrate at a rate of about 30 nm/hr to about 1000 nm/hr.
17. The method of claim 16 , wherein the silicon carbide is removed from the substrate at a rate of about 100 nm/hr to about 500 nm/hr.
18. The method of claim 1 , wherein the liquid carrier with any components dissolved or suspended therein has a pH of about 3 or less.
19. The method of claim 18 , wherein the liquid carrier with any components dissolved or suspended therein has a pH of about 2 or less.
20. The method of claim 1 , wherein the oxidizing agent is present in an amount of about 0.001 wt. % to about 2 wt. % based on the weight of the liquid carrier and any components dissolved or suspended therein.
21. The method of claim 20 , wherein the oxidizing agent is present in an amount of about 0.001 wt. % to about 0.5 wt. % based on the weight of the liquid carrier and any components dissolved or suspended therein.
22. The method of claim 1 , wherein the single crystal silicon carbide is 4HN polytype.
23. The method of claim 1 , wherein the single crystal silicon carbide is 6HPSI polytype.