Chemical mechanical polishing of group III-nitride surfaces
A method of chemically-mechanically polishing a substrate having a Group III-nitride surface includes providing a chemical-mechanical polishing slurry composition. The slurry composition includes a slurry solution including a liquid carrier and an oxidizer including a transition metal or a per-based compound. The slurry solution includes at least one component that reacts with the Group III-nitride surface to form a softened Group III-nitride surface. The Group III-nitride comprising surface is contacted with the slurry composition by a pad to form the softened Group III-nitride surface. The pad is moved relative to the softened Group III-nitride surface, wherein at least a portion of the softened Group III-nitride surface is removed.
1. A method of chemically-mechanically polishing a substrate having a Group III-nitride comprising surface, comprising:
providing a chemical-mechanical polishing slurry composition, said slurry composition comprising:
a slurry solution including a liquid carrier, an oxidizer comprising a per-based compound in a concentration range from 0.05 M to 0.4 M, in a pH range from 1 to 7, and a plurality of coated particles having a hard core and a soft surface that provides a lower hardness compared to said hard core by at least one (1) Mohs number or at least a Knoop hardness of 100 Kg/mm 2 , wherein said lower hardness is less than a 6 Mohs number or a Knoop hardness less than 900 Kg/mm 2 , wherein said slurry solution includes at least one component that reacts with said Group III-nitride comprising surface to form a softened Group III-nitride comprising surface;
dispensing said slurry composition to contact said Group III-nitride comprising surface to form said softened Group III-nitride comprising surface by pressing a polymeric polishing pad having a Mohs hardness less than 6 or Knoop Hardness less than 900 Kg/mm 2 onto said Group III-nitride comprising surface, and
moving said polishing pad relative to said softened Group III-nitride comprising,
wherein at least a portion of said softened Group III-nitride comprising surface is removed.
2. The method of claim 1 , wherein said per-based compound breaks down into at least one insoluble byproduct during said method, and wherein said insoluble byproducts coat said polishing pad with a coating following said dispensing.
3. The method in claim 1 where said per-based compound comprises a permanganate.
4. The method of claim 1 , wherein said soft surface comprises a Mn comprising compound in which Mn is in a Mn +3 or Mn +4 state.
5. The method of claim 4 , wherein said Mn comprising compound consists essentially of at least one of MnO 2 , MnCl 3 , and Mn 2 O 3 .
6. The method of claim 5 , wherein said Mn comprising compound comprises at least two of said MnO 2 , said MnCl 3 and said Mn 2 O 3 .
7. The method of claim 2 , wherein said coating comprises a discontinuous coating.
8. The method of claim 2 , wherein said coating comprises a continuous coating.
9. The method of claim 1 , wherein a pH during said method is <3.
10. The method of claim 1 , wherein said group III-nitride comprising surface comprises GaN.
11. The method of claim 1 , wherein said group III-nitride comprising surface consists essentially of a Group III-nitride surface, and a polishing rate for said Group III-nitride surface is ≧100 nm/hr.
12. A method of chemically-mechanically polishing a substrate having a Group III-nitride comprising surface, comprising:
providing a chemical-mechanical polishing slurry composition, said slurry composition comprising:
a slurry solution including a liquid carrier, an oxidizer comprising a per-based compound, in a concentration range from 0.05 M to 0.4 M, in a pH range from 1 to 7, and a plurality of particles having a soft surface including Mn comprising compounds in which Mn is in a Mn +3 and in a Mn +4 state, wherein said slurry solution includes at least one component that reacts with said Group III-nitride comprising surface to form a softened Group III-nitride comprising surface;
dispensing said slurry composition to contact said Group III-nitride comprising surface to form said softened Group III-nitride comprising surface by pressing a polishing pad onto said Group III-nitride comprising surface, and
moving said polymeric polishing pad having a Mohs hardness less than 6 or Knoop Hardness less than 900 Kg/mm 2 relative to said softened Group III-nitride comprising,
wherein at least a portion of said softened Group III-nitride comprising surface is removed.
13. The method of claim 12 , wherein said Mn comprising compounds include both MnO 2 and MnCl 3 .
14. The method of claim 1 , wherein said pH range is from 1 to 5.
15. The method of claim 12 , wherein said wherein said pH range is from 1 to 5.