Micropillar-enabled thermal ground plane

Patent metadata

Field	Value
Publication number	US-10731925-B2
Application number	US-201514857567-A
Country	US
Kind code	B2
Filing date	Sep 17, 2015
Priority date	Sep 17, 2014
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

Abstract

A thermal ground plane (TGP) is disclosed. A TGP may include a first planar substrate member configured to enclose a working fluid; a second planar substrate member configured to enclose the working fluid; a plurality of wicking structures disposed on the first planar substrate; and one or more planar spacers disposed on the second planar substrate. The first planar substrate and the second planar substrate are may be hermetically sealed.

First claim

That which is claimed:

1. A thermal ground plane comprising:
a first planar substrate member configured to enclose a working fluid, wherein the first planar substrate member comprises a polymer and copper, and wherein the first planar substrate member has a thickness less than 60 microns;
a second planar substrate member configured to enclose the working fluid, wherein a perimeter of the first planar substrate member and a perimeter of the second planar substrate member are hermetically sealed together by thermo-compression bonding, wherein the second planar substrate member has a thickness less than 60 microns, wherein the second planar substrate member consists essentially of a metal;
a first plurality of pillars disposed on an interior surface of the first planar substrate member;
a mesh layer disposed on the top of the first plurality of pillars and bonded with the top of the first plurality of pillars, wherein the mesh layer consists essentially of copper, or polymer encapsulated with copper, or stainless steel encapsulated with copper; and
a second plurality of pillars disposed on an interior surface of the second planar substrate member within an area defined by the perimeter of the second planar substrate member and the second plurality of pillars extend from the second planar substrate member to the mesh layer and are not in contact with the first planar substrate member, wherein the spacing between each pillar of the second plurality of pillars is larger than two times of the diameter of each pillar of the second plurality of pillars;
wherein the thermal ground plane has a thickness less than 300 microns.

2. The thermal ground plane according to claim 1 , wherein the first planar substrate member and/or the second planar substrate member comprise at least one of a polymer-coated metallic layer, a copper-cladded polymer layer with thermal vias, a copper-cladded polymer layer without thermal vias, a polymer layer encapsulated by a copper layer, a polymer layer encapsulated by a hydrophilic coating, and/or a polymer layer encapsulated by a hydrophobic coating.

3. The thermal ground plane according to claim 1 , wherein the first plurality of pillars comprises copper pillars.

4. The thermal ground plane according to claim 1 , wherein the first plurality of pillars comprises a plurality of copper pillars or channels.

5. The thermal ground plane according to claim 1 , wherein one or more of the first plurality of pillars have a cross-section comprising a rectangular cross section, a circular cross section, and/or a star-shaped cross section.

6. The thermal ground plane according to claim 1 , wherein the mesh layer comprises a mesh selected from the list consisting of copper mesh, polymer mesh encapsulated with copper, and copper-encapsulated stainless steel mesh.

7. The thermal ground plane according to claim 1 , wherein the mesh layer includes a hydrophilic coating or a hydrophobic coating.

8. The thermal ground plane according to claim 1 , wherein the first plurality of pillars are deposited using a lithographic patterning process.

9. The thermal ground plane according to claim 1 , wherein the dimensions of the second plurality of pillars are different than the dimensions of the first plurality of pillars.

10. The thermal ground plane according to claim 1 , wherein the thermal ground plane is flexible.

11. The thermal ground plane according to claim 1 , wherein each of the first plurality of pillars extends from the interior surface of the first planar substrate member and wherein each of the first plurality of pillars is not in contact with the second planar substrate member.

12. The thermal ground plane according to claim 1 , wherein the mesh layer comprises a hydrophilic coating that comprises one or more coatings consisting selected from the group consisting of copper, Al 2 O 3 , TiO 2 , and SiO 2 .

13. The thermal ground plane according to claim 1 , wherein the mesh layer is bonded on the top of the first plurality of pillars.

14. The thermal ground plane according to claim 1 , wherein the mesh layer comprises a woven mesh.

15. The thermal ground plane according to claim 1 , wherein the second planar substrate layer comprises a metallic layer, a polymer-coated metallic layer, a metallic layer encapsulated by a hydrophilic coating, or a copper metallic layer encapsulated by a hydrophilic/hydrophobic coating.

16. The thermal ground plane according to claim 1 , wherein the metal comprises copper.

17. The thermal ground plane according to claim 1 , wherein the mesh layer comprises a plurality of mesh layers.

18. A thermal ground plane comprising:
a first planar substrate member that encloses a working fluid, wherein the first planar substrate member comprises stainless steel and copper, and wherein the first planar substrate member has a thickness less than 60 microns;
a second planar substrate member that encloses the working fluid, wherein a perimeter of the first planar substrate member and a perimeter of the second planar substrate member are hermetically sealed together by thermo-compression bonding, wherein the second planar substrate member has a thickness less than 60 microns, wherein the second planar substrate member consists essentially of a metal;
a first plurality of pillars disposed on an interior surface of the first planar substrate member;
a mesh layer disposed on the top of the first plurality of pillars and bonded with a top portion of the first plurality of pillars, wherein the mesh layer consists essentially of copper, or polymer encapsulated with copper, or stainless steel encapsulated with copper, and wherein the mesh layer comprises three or more mesh layers; and
a second plurality of pillars disposed on an interior surface of the second planar substrate member within an area defined by the perimeter of the second planar substrate member, and the second plurality of pillars extend from the second planar substrate member to the mesh layer, and the second planar substrate member are not in contact with the first planar substrate member,
wherein the spacing between each pillar of the second plurality of pillars is larger than two times of the diameter of each pillar of the second plurality of pillars.

19. The thermal ground plane according to claim 18 , wherein each mesh layer of the three or more mesh layers comprises the same material as the other mesh layers of the three or more mesh layers.

20. The thermal ground plane according to claim 18 , wherein each mesh layer of the three or more mesh layers comprises a different material than the other mesh layers of the three or more mesh layers.

21. The thermal ground plane according to claim 18 , wherein the spacing between each pillar of the second plurality of pillars is larger than two times of the diameter of each pillar of the second plurality of pillars.

22. The thermal ground plane according to claim 18 , wherein the perimeter of the first planar substrate member and the perimeter of the second planar substrate member are hermetically sealed together with a low temperature sintered interface.

23. The thermal ground plane according to claim 18 , wherein the perimeter of the first planar substrate member and the perimeter of the second planar substrate member are hermetically sealed together by thermo-compression bonding.

24. The thermal ground plane according to claim 18 , wherein the mesh layer is bonded on the top of the first plurality of pillars.

Assignees

• Kelvin Thermal Tech Inc
• Univ Colorado Regents

Inventors

• Lewis Ryan John
• Liew Li-Anne
• Lin Ching-Yi
• Coolidge Collin Jennings
• Xu Shanshan
• Yang Ronggui
• Lee Yung-Cheng

Classifications

• H10W40/73

  for cooling by change of state · CPC title

• F28D15/046 Primary

  characterised by the material or the construction of the capillary structure · CPC title

• F28F21/085

  from copper or copper alloys · CPC title

• F28D15/0233

  the conduits having a particular shape, e.g. non-circular cross-section, annular (F28D15/0241, F28D15/0266 take precedence) · CPC title

• F28F2240/00

  Spacing means · CPC title