CMP method for forming smooth diamond surfaces

Patent metadata

Field	Value
Publication number	US-9259819-B2
Application number	US-201414494276-A
Country	US
Kind code	B2
Filing date	Sep 23, 2014
Priority date	Nov 6, 2012
Publication date	Feb 16, 2016
Grant date	Feb 16, 2016

Abstract

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.

First claim

The invention claimed is:

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.

Assignees

• Sinmat Inc
• Univ Florida

Inventors

• Singh Rajiv K
• Singh Deepika
• Arjunan Arul Chakkaravarthi

Classifications

• H10P52/403

  of conductive or resistive materials · CPC title

• H10P52/402

  of semiconductor materials · CPC title

• H10P50/283

  by chemical means · CPC title

• H10D62/8503

  Nitride Group III-V materials, e.g. AlN or GaN · CPC title

• H10D62/8303

  Diamond · CPC title