CMP method for forming smooth diamond surfaces
A method of chemical mechanical polishing (CMP) a diamond containing surface includes providing a slurry including a plurality of particles, at least one oxidizer, and at least one acid, wherein the slurry has a pH≦3 or pH greater than 11. At least an outer surface of the plurality of particles is softer than the diamond surface or the particles are diamond particles averaging less than (<) 2 μm in size. The diamond surface is pressed with respect to a polishing pad providing a Shore D Hardness less than 99 having the slurry in between while rotating the polishing pad relative to the diamond surface to form a smooth diamond surface having a root mean square (rms) surface roughness less than 15 nm.
1. A method of chemical mechanical polishing (CMP) a diamond surface comprising:
providing a slurry comprising a plurality of particles, at least one oxidizer, and at least one acid or base, wherein said slurry has a pH less than or equal to (≦) 3 or greater (>) than 11, wherein at least an outer surface of said plurality of particles is softer than said diamond surface or said plurality of particles are diamond particles averaging less than (<) 2 μm in size;
pressing said diamond surface with a pad having a Shore D Hardness less than (<) 99 having said slurry in between while rotating said pad relative to said diamond surface to form a smooth diamond surface having a root mean square (rms) surface roughness less than 15 nm.
2. The method of claim 1 , wherein said pad comprises a soft cloth, metallic woolen pad or polymeric polishing pad with said Shore D hardness less than (<) 90.
3. The method of claim 1 , wherein said plurality of particles comprise alumina, titania or silica.
4. The method of claim 1 , wherein said oxidizer comprises a transition metal compound or a per compound.
5. The method of claim 4 , wherein said oxidizer comprises KMnO4 or a K2S2O8 compound.
6. The method of claim 1 , wherein said diamond surface is a composite of cobalt-diamond or nickel-diamond, or diamond particles protruding from a matrix.
7. The method of claim 1 , wherein a polishing pressure used for said pressing is less than 10 psi.
8. The method of claim 1 , wherein said slurry comprises at least one surfactant.
9. A method of chemical mechanical polishing (CMP) a diamond surface, comprising:
providing a slurry comprising a plurality of particles, wherein at least an outer surface of said plurality of particles is softer than said diamond surface, at least one oxidizer comprising a transition metal compound or a per compound, and at least one acid, wherein said slurry has a pH less than or equal to (≦) 3;
pressing said diamond surface with a soft cloth, or metallic woolen pad or polymeric polishing pad having a Shore D Hardness less than (<) 99 with said slurry in between while rotating said polishing pad relative to said diamond surface to form a smooth diamond surface having a root mean square (rms) surface roughness less than (<) 10 nm.
10. The method of claim 9 , when a polishing pressure used for said pressing is less than 10 psi.
11. The method of claim 9 , wherein said slurry comprises at least one surfactant.
12. The method of claim 9 , wherein said rms surface roughness is less than (<) 1 nm.