Polycrystalline ceramic substrate and method of manufacture

Patent metadata

Field	Value
Publication number	US-10134589-B2
Application number	US-201715621235-A
Country	US
Kind code	B2
Filing date	Jun 13, 2017
Priority date	Jun 24, 2016
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

A method of fabricating a ceramic substrate structure includes providing a ceramic substrate, encapsulating the ceramic substrate in a barrier layer, and forming a bonding layer coupled to the barrier layer. The method further includes removing a portion of the bonding layer to expose at least a portion of the barrier layer and define fill regions, and depositing a second bonding layer on the at least a portion of the exposed barrier layer and the fill regions.

First claim

What is claimed is:

1. A method of fabricating a substantially planar ceramic substrate structure, the method comprising:
providing a ceramic substrate having a front surface characterized by a plurality of naturally occurring voids, the ceramic substrate comprising a polycrystalline material;
encapsulating the ceramic substrate in a barrier layer;
forming a bonding layer comprising a bonding layer material and coupled to the barrier layer on the front surface of the ceramic substrate;
removing a portion of the bonding layer to expose at least a portion of the barrier layer and to define fill regions filled with the bonding layer material in spaces of the plurality of naturally occurring voids; and
depositing a second bonding layer on the at least a portion of the exposed barrier layer and the fill regions.

2. The method of claim 1 wherein the ceramic substrate comprises polycrystalline aluminum nitride.

3. The method of claim 1 wherein removing the portion of the bonding layer comprises a chemical-mechanical polishing (CMP) process.

4. The method of claim 3 wherein the CMP process terminates at the barrier layer.

5. The method of claim 4 wherein the barrier layer comprises silicon nitride.

6. The method of claim 1 wherein the front surface of the ceramic substrate is characterized by an RMS roughness in the range of 50-600 nm and the second bonding layer is characterized by an RMS roughness in the range of 0.5-5 nm.

7. The method of claim 1 wherein the bonding layer comprises silicon oxide and the second bonding layer comprises a silicon oxide layer between 100 nm and 1,000 nm in thickness.

8. The method of claim 1 wherein the second bonding layer comprises a different material than the bonding layer.

9. The method of claim 8 wherein the bonding layer comprises silicon oxide and the second bonding layer comprises DLC.

10. The method of claim 1 further comprising, after removing a portion of the bonding layer, forming a second barrier shell encapsulating the exposed barrier layer and the fill regions.

11. The method of claim 1 wherein forming the bonding layer comprises repeating a cycle of deposition/polishing one or more times.

12. The method of claim 11 wherein the repeated cycle of deposition/polishing comprises deposition of different materials.

13. The method of claim 1 further comprising:
joining a substantially single crystal layer to the second bonding layer, wherein the substantially single crystal layer is characterized by a first surface roughness;
processing the substantially single crystal layer to form a growth surface characterized by a second surface roughness less than the first surface roughness; and
forming an epitaxial layer coupled to the growth surface.

14. A method of fabricating a substantially planar ceramic substrate structure, the method comprising:
providing a ceramic substrate having a front surface characterized by a plurality of naturally occurring peaks, the ceramic substrate comprising a polycrystalline material;
forming a bonding layer comprising a bonding layer material and coupled to the front surface of the ceramic substrate;
performing a chemical-mechanical polishing (CMP) process to remove a portion of the bonding layer to expose at least a portion of the front surface of the ceramic substrate and to define fill regions filled with the bonding layer material between adjacent peaks of the plurality of naturally occurring peaks on the front surface of the ceramic substrate; and
encapsulating the ceramic substrate in a barrier layer.

15. The method of claim 14 further comprising depositing an adhesion promotion layer between the front surface of the ceramic substrate and the bonding layer.

16. The method of claim 14 wherein, the ceramic substrate comprises polycrystalline aluminum nitride.

17. The method of claim 14 further comprising depositing an electrically conductive layer coupled to at least a portion of the barrier layer.

18. The method of claim 14 further comprising depositing a thermally conductive layer coupled to at least a portion of the barrier layer.

19. The method of claim 14 further comprising depositing a second bonding layer coupled to at least a portion of the barrier layer.

20. The method of claim 14 further comprising:
depositing an electrically conductive layer coupled to at least a portion of the barrier layer;
depositing a thermally conductive layer coupled to at least a portion of the electrically conductive layer; and
depositing a second bonding layer coupled to at least a portion of the thermally conductive layer.

Assignees

• Qromis Inc

Inventors

• Odnoblyudov Vladimir
• Basceri Cem
• Farrens Shari

Classifications

• H10P14/3416

  Nitrides · CPC title

• H10P14/3411

  Silicon, silicon germanium or germanium · CPC title

• H10P14/3258

  Crystal orientation · CPC title

• H10P14/3211

  Silicon, silicon germanium or germanium · CPC title

• H10P14/2925

  Surface structures · CPC title