Silicon carbide polishing method utilizing water-soluble oxidizers

Abstract

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, 
 (b) an abrasive suspended in the liquid carrier, wherein the abrasive is alumina and is present in an amount of about 3 wt. % or less based on the weight of the liquid carrier and any components dissolved or suspended therein, and 
 (c) an oxidizing agent, 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, and is selected from the group consisting of hydrogen peroxide, oxone, ammonium cerium nitrate, periodates, iodates, persulfates, and mixtures thereof, and 
   (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 about 1 wt. % or less based on the weight of the liquid carrier and any components dissolved or suspended therein. 
   
   
       3 . The method of  claim 1 , wherein the abrasive comprises particles having an average particle size of about 130 nm or less. 
   
   
       4 . The method of  claim 1 , wherein the liquid carrier comprises water. 
   
   
       5 . The method of  claim 1 , wherein the oxidizing agent is present in an amount of about 0.001 wt. % to about 0.1 wt. % based on the weight of the liquid carrier and any components dissolved or suspended therein. 
   
   
       6 . The method of  claim 1 , wherein the liquid carrier with any components dissolved or suspended therein has a pH of about 5 or less. 
   
   
       7 . The method of  claim 1 , wherein the oxidizing agent is potassium periodate, potassium iodate, ammonium persulfate, or potassium persulfate. 
   
   
       8 . The method of  claim 1 , wherein the alumina is seeded gel process-alpha alumina. 
   
   
       9 . 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.