Polishing silicon carbide
View Patent ↗The invention provides a method of chemically-mechanically polishing a substrate comprising at least one layer of single crystal silicon carbide. The method utilizes a chemical-mechanical polishing composition comprising a liquid carrier, an abrasive, a catalyst comprising a transition metal composition, and an oxidizing agent.
1. A method of chemically-mechanically polishing a substrate comprising:
(i) providing a substrate comprising at least one layer of single crystal silicon carbide,
(ii) contacting the substrate with a chemical-mechanical polishing composition comprising:
(a) a liquid carrier,
(b) an abrasive,
(c) a catalyst comprising a metal composition, wherein the metal is Co or Pt, and
(d) an oxidizing agent that oxidizes silicon carbide,
(iii) moving the polishing composition relative to the substrate, and
(iv) abrading at least a portion of the silicon carbide of the substrate to polish the substrate.
2. The method of claim 1 , wherein the oxidizing agent is selected from the group consisting of persulfates, organic peroxides, inorganic peroxides, peroxyacids, permanganates, chromates, percarbonates, chlorates, bromates, iodates, perchloric acid and salts thereof, perbromic acid and salts thereof, periodic acid and salts thereof, hydroxylamine and salts thereof, ferricyanide, oxone, and combinations thereof.
3. The method of claim 2 , wherein the oxidizing agent is periodic acid, ammonium persulfate, potassium persulfate, or potassium permanganate.
4. The method of claim 1 , wherein the oxidizing agent is present in an amount of about 0.001 wt. % to about 5 wt. % based on the weight of the liquid carrier and any components dissolved or suspended therein.
5. The method of claim 1 , wherein the abrasive is selected from the group consisting of silica, alumina, titania, zirconia, ceria, magnesia, and combinations thereof.
6. The method of claim 5 , wherein the abrasive is alumina.
7. The method of claim 1 , wherein the abrasive is present in an amount of about 0.05 wt. % to about 5 wt. % based on the weight of the liquid carrier and any components dissolved or suspended therein.
8. The method of claim 7 , wherein the abrasive is present in an amount of about 0.1 wt. % to about 0.8 wt. % based on the weight of the liquid carrier and any components dissolved or suspended therein.
9. The method of claim 1 , wherein the metal composition comprises a ligand selected from the group consisting of nitrate, fluoride, chloride, chlorate, dimethylolpropionate, formate, bromide, bromate, iodide, iodate, hydrido, sulfate, phosphate, acetate, oxalate, acetylacetonate, citrate, tartrate, malonate, gluconate, phthalate, succinate, perchlorate, perbromate, and periodate.
10. The method of claim 1 , wherein the metal composition is Co(NO 3 ) 2 ·6H 2 O.
11. The method of claim 1 , wherein the metal composition is H 2 PtCl 6 .
12. The method of claim 1 , wherein the catalyst is present in an amount of about 5 ppm to about 5000 ppm.
13. The method of claim 12 , wherein the catalyst is present in an amount of about 3000 ppm to about 4000 ppm.
14. The method of claim 1 , wherein the liquid carrier is water.
15. The method of claim 1 , wherein the abrasive is alumina, and the oxidizing agent is potassium persulfate or ammonium persulfate.
16. The method of claim 1 , wherein the abrasive is alumina, and the oxidizing agent is a permanganate or a periodate.
17. The method of claim 15 , wherein the alumina is present in an amount of about 0.5 wt. % to about 0.7 wt. % based on the weight of the liquid carrier and any components dissolved or suspended therein.
18. The method of claim 16 , wherein the alumina is present in an amount of about 0.5 wt. % to about 0.7 wt. % based on the weight of the liquid carrier and any components dissolved or suspended therein.
19. The method of claim 15 , wherein the persulfate is present in an amount of about 0.2 wt. % to about 0.5 wt. %, and the catalyst is present in an amount of about 3000 ppm to about 5000 ppm.
20. The method of claim 16 , wherein the oxidizing agent is a periodate and is present in an amount of about 0.2 wt. % to about 0.5 wt. %, and the catalyst is cobalt and is present in an amount of about 3000 ppm to about 5000 ppm.
21. The method of claim 1 , wherein the oxidizing agent is a persulfate, permanganate, or periodate and is present in an amount of about 0.1 wt. % to about 0.5 wt. %, and the catalyst is platinum and is present in an amount of about 100 ppm to about 1000 ppm.