Isolated thermal interface

• US 7,166,912 B2
• Filed: 04/05/2001
• Issued: 01/23/2007
• Est. Priority Date: 04/05/2001
• Status: Expired due to Term

• Current Assignee: NeoGraf Solutions, LLC
• Original Assignee: Advanced Energy Technology Inc. (Graftech International Limited)
• Inventors: Krassowski, Daniel Witold, Tzeng, Jing-Wen
• Primary Examiner(s): Owens; Douglas W.
• Application Number:
  US09/826,676
• Publication Number:
  US 20020163076A1
• Time in Patent Office: 2,119 Days
• Field of Search: 257/712, 257/706, 257/702, 257/675, 257/705, 257/717, 438/122, 427/249.6
• US Class Current: 257/712
• CPC Class Codes: B32B 27/06 as the main or only constituent of a layer, which is next to another layer of the same or of a different material next to a layer of a particular substance B32B9/045; next to a bituminous or tarry layer B32B11/046; next to a water setting substance layer B32B13/12; next to a metal layer B32B15/08; next to a glass layer B32B17/10; next to a layer formed of natural mineral fibres or particles B32B19/045; next to a wood layer B32B21/08; next to a cellulosic plastic layer B32B23/08; next to a natural or synthetic rubber layer B32B25/08
• CPC Class Codes: C09D 5/00 Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced electrically insulating plastics, resins or waxes H01B3/30; Filling pastes
• 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 23/3735 Laminates or multilayers, e.g. direct bond copper ceramic substrates
• 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

Abstract

An isolated thermal interface is presented. The inventive interface includes a flexible graphite sheet having two major surfaces, at least one of the major surfaces coated with a protective coating sufficient to inhibit flaking of the particles of graphite.

Claims

1. An isolated thermal interface comprising a sheet of compressed particles of exfoliated graphite, the sheet having two major surfaces and at least one edge surface, the major surfaces and at least one edge surface being coated with a protective coating sufficient to inhibit flaking of the particles of graphite.

2. The thermal interface of claim 1 wherein the protective coating comprises a thermoplastic material.

3. The thermal interface of claim 2 wherein the thermoplastic comprises polyethylene, a polyester or a polyimide.

4. The thermal interface of claim 1 wherein the protective coating is no more than about 0.025 millimeters in thickness.

5. The thermal interface of claim 1 wherein the protective coating is effective to electrically isolate the coated major surface of the sheet.

6. The thermal interface of claim 1 which further comprises a layer of adhesive interposed between the protective coating and the sheet.

7. The thermal interface of claim 6 wherein the adhesive is selected from the group consisting of acrylic and latex materials.

8. The thermal interface of claim 6 wherein the layer of adhesive is no more than about 0.015 millimeters in thickness.

9. A process for producing a thermal interface having protective coating sufficient to inhibit flaking of the particles of graphite, the process comprising (a) forming a sheet comprising compressed particles of exfoliated graphite, into the size and shape desired for a thermal interface, wherein the formed sheet has two major surfaces and at least one edge surface, and wherein the sheet has its directions of greater thermal conductivity parallel to the major surface;

and (b) coating the major surfaces of the formed sheet with a material to form a protective coating, such that the material forms a protective boundary about the sheet wherein the material is coated on the formed sheet so as to flow completely about at least one of the edge surfaces of the sheet, and extend beyond at least one of the edge surfaces of the sheet.

10. The process of claim 9 wherein the material is coated on the formed sheet by spray coating, roller coating or hot laminating press.

11. The process of claim 9 wherein the material is coated on the formed sheet by roller coating, laminating with adhesive, or hot press laminating, and then cutting the formed sheet into the desired size and shape of the thermal interface.

12. The process of claim 9 wherein the material comprises a thermoplastic material.

13. The process of claim 12 wherein the material comprises polyethylene, a polyester or a polyimide.

14. The process of claim 9 wherein the material is no more than about 0.025 millimeters in thickness.

15. The process of claim 9 wherein an adhesive is coated on the formed sheet between the material and the formed sheet.

16. The process of claim 15 wherein the adhesive comprises an acrylic or a latex material.

17. The process of claim 16 wherein the layer of adhesive is no more than about 0.015 millimeters in thickness.

18. An electronic device comprising

(a) an electronic component;

and

(b) a thermal interface comprising a sheet of compressed particles of exfoliated graphite having two major surfaces, one of the major surfaces being in contact with the electronic component and the other of the major surfaces coated with a protective coating sufficient to inhibit flaking of the particles of graphite.

19. The device of claim 18 wherein the protective coating comprises a thermoplastic material.

20. The device of claim 19 wherein the thermoplastic comprises polyethylene, a polyester or a polyimide.

21. The device of claim 18 wherein the protective coating is no more than about 0.025 millimeters in thickness.

22. The device of claim 18 wherein the protective coating is effective to electrically isolate the coated major surface of the sheet of flexible graphite particles.

23. The device of claim 18 wherein the graphite sheet has edge surfaces, and at least one edge surface of the sheet of compressed particles of exfoliated graphite is coated with a protective coating sufficient to inhibit flaking of particles of graphite.