Heat dissipating component using high conducting inserts

• US 20030116312A1
• Filed: 12/13/2001
• Published: 06/26/2003
• Est. Priority Date: 12/13/2001
• Status: Active Grant

• Current Assignee: NeoGraf Solutions, LLC
• Original Assignee: Graftech, Incorporated
• Inventors: Krassowski, Daniel W., Chen, Gary G.
• Granted Patent: US 6,758,263 B2
• Time in Patent Office: Days
• US Class Current: 165/185
• CPC Class Codes: F28F 13/00 Arrangements for modifying heat-transfer, e.g. increasing, decreasing F28F1/00 - F28F11/00 take precedence
• CPC Class Codes: F28F 21/02 of carbon, e.g. graphite
• CPC Class Codes: H01L 23/3672 Foil-like cooling fins or heat sinks being part of lead-frames H01L23/49568
• CPC Class Codes: H01L 23/373 Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
• CPC Class Codes: H01L 23/3733 having a heterogeneous or anisotropic structure, e.g. powder or fibres in a matrix, wire mesh, porous structures H01L23/3732, H01L23/3737 take precedence
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10S 165/905 Materials of manufacture

Abstract

A thermal management system provides a heat dissipating component using a high thermal conductivity insert. The heat dissipating component may be a spreader or heat sink, and includes a planar graphite member having high thermal conductivity along the plane of the member and having a relatively low thermal conductivity through the thickness of the member. A cavity is formed through the thickness of the member and the high conductivity insert is received in the cavity. The insert may be an isotropic high thermal conductivity material such as copper or an anisotropic material such as graphite oriented to have high conductivity in the direction of the thickness of the planar element.

Claims

1. A thermal management system, comprising:

an anisotropic graphite planar element having a relatively high thermal conductivity in the plane of the planar element and having a relatively low thermal conductivity across a thickness of the planar element in a direction normal to the plane of the planar element, the planar element having a cavity defined therein; and

a core closely received in the cavity, the core being constructed of an isotropic core material so that heat from a heat source can be conducted via the core into the thickness of the planar element and then out across the plane of the planar element.

2. The system of claim 1, wherein the planar element is shrink fit with the core by thermal expansion and contraction of at least one of the planar element and the core.

3. The system of claim 1, further comprising:

a lubricant layer between the core and the cavity of the planar element, so that the lubricant layer provides a thermal interface between the core and the planar element.

4. The system of claim 1, wherein:

the planar element comprises a plurality of anisotropic graphite sheets laminated together, the sheets being oriented parallel to the plane of the planar element.

5. The system of claim 4, wherein the graphite sheets are resin impregnated.

6. The system of claim 4, wherein the core extends completely through the laminated graphite sheets.

7. The system of claim 1, wherein the core material is a metal.

8. The system of claim 1, wherein the core material comprises copper.

9. The system of claim 1, wherein the core is a cylindrical shaped core having a cylindrical axis oriented normal to the plane of the planar element.

10. The system of claim 1, further comprising:

a heat source having a heat conducting area defined thereon in contact with the core.

11. The system of claim 10, wherein:

the heat conducting area of the heat source is a top surface of the heat source; and

the entire top surface of the heat source is covered by and in contact with the core.

12. The system of claim 1, wherein the system is a heat spreader.

13. The system of claim 1, wherein the system is a heat sink.

14. A thermal management system, comprising:

a heat source having a heat transmitting surface;

an anisotropic graphite planar element, said element having x and y dimensions defining a generally planar extent of the planar element and having a z dimension defining a thickness of the planar element, the planar element having a relatively high thermal conductivity in the x and y directions and a relatively low thermal conductivity in the z direction, the planar element having a cavity defined therein extending at least partially through the thickness of the planar element; and

an insert received in the cavity in heat conducting engagement with the planar element, the insert having a heat receiving surface operatively engaging the heat transmitting surface of the heat source, so that heat from the heat source flows across the heat transmitting surface and the heat receiving surface, into the insert in the z direction and then out through the planar element in the x and y directions.

15. The system of claim 14, wherein:

the heat transmitting surface of the heat source is entirely covered by the heat receiving surface of the insert.

16. The system of claim 14, wherein:

the insert is constructed from an isotropic material.

17. The system of claim 16, wherein the isotropic material of the insert is copper.

18. The system of claim 14, wherein:

the insert is constructed from an anisotropic material.

19. The system of claim 18, wherein:

the anisotropic material is graphite.

20. The system of claim 14, wherein:

the cavity and the insert both extend completely through the thickness of the planar element.

21. The system of claim 14, wherein:

the cavity and the insert both extend partially through the thickness of the planar element.

22. The system of claim 14, wherein:

the planar element comprises a plurality of graphite sheets laminated together.

23. The system of claim 22, wherein:

the graphite sheets are resin impregnated.

24. A method of dissipating heat from a heat source, comprising:

(a) providing an anisotropic heat dissipating element having relatively high thermal conductivity in x and y directions, and having relatively low thermal conductivity in a z direction perpendicular to the x and y directions, the heat dissipating element having a cavity defined therethrough in the z direction, and having an isotropic heat conducting insert disposed in the cavity;

(b) placing the insert in heat conducting relationship with a heat source;

(c) conducting heat from the heat source through the insert and into the anisotropic heat dissipating element; and

(d) conducting heat through the heat dissipating element in the x and y directions.