Bendable heat spreader with metallic wire mesh-based microstructure and method for fabricating same

• US 20060098411A1
• Filed: 05/27/2005
• Published: 05/11/2006
• Est. Priority Date: 11/11/2004
• Status: Abandoned Application

• Current Assignee: Taiwan Microloops Corp.
• Original Assignee: Taiwan Microloops Corp.
• Inventors: Lin, Chien-Hung, Su, Cherng-Yuh, Lee, Kuo-Ying, Chiu, Chien-Wen
• Application Number:
  US11/138,478
• Publication Number:
  US 20060098411A1
• Time in Patent Office: Days
• US Class Current: 361/704
• CPC Class Codes: F28D 15/0233 the conduits having a particular shape, e.g. non-circular cross-section, annular F28D15/0241, F28D15/0266 take precedence
• CPC Class Codes: F28D 15/046 characterised by the material or the construction of the capillary structure
• CPC Class Codes: H01L 23/427 Cooling by change of state, e.g. use of heat pipes by liquefied gas H01L23/445
• 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: Y10T 29/4935 Heat exchanger or boiler making

Abstract

The present invention discloses a heat spreader and method for making the heat spreader. The heat spreader comprises: a hollow metallic housing including an upper cover having an inner surface and a lower cover having an inner surface, the upper and lower covers being bonded together along their perimeters defining a cavity; a capillary structure in a form of metallic meshes bonded to the inner surfaces of the upper and lower covers of the metallic housing; a plurality of reinforcing members disposed in the cavity and bonded between the inner surfaces of the upper and lower covers of the metallic housing; and a working fluid receive in the cavity; wherein bonded surfaces between the metallic meshes and the inner surfaces of the metallic housing, the upper cover and the lower cover, and the reinforcing members and the inner surfaces of the metallic housing all are diffusion-bonded interfaces.

Claims

1. A method for fabricating a heat spreader, comprising:

providing an upper cover and a lower cover, each of the covers being a sheet of metallic material and having a perimeter and an inner surface;

attaching metallic meshes to the inner surface of the upper cover and the inner surface of the lower cover using diffusion bonding so as to form a capillary structure on the respective inner surface;

interposing a plurality of reinforcing members between the inner surfaces of the upper cover and the lower cover to which the metallic meshes are attached;

bonding the upper cover, the lower cover and the reinforcing members together using diffusion bonding, such that the inner surfaces of the upper cover and the lower cover define a cavity and the reinforcing members are bonded therebetween;

evacuating the cavity to form a vacuum;

filling a working fluid into the evacuated cavity; and

sealing the cavity with the working fluid therein.

2. A method according to claim 1, wherein the upper cover, the lower cover and the meshes are made from copper, respectively.

3. A method according to claim 2, wherein the reinforcing members comprise copper posts or copper strips, or a combination thereof.

4. A method according to claim 1, wherein the metallic material for the upper cover and the lower cover is aluminum and the metallic meshes are copper meshes.

5. A method according to claim 4, wherein the reinforcing members comprise aluminum posts or aluminum strips, or a combination thereof.

6. A method according to claim 1, wherein the reinforcing members are bonded between the metallic mesh attached to the upper cover and the metallic mesh attached to the lower cover.

7. A method according to claim 1, wherein each of the metallic meshes has a plurality of openings, and the reinforcing members pass through the openings to connect the inner surfaces of the upper cover and the lower cover.

8. A method according to claim 2, wherein the diffusion bonding is performed at a temperature ranging from 450°

C. to 900°

C. and under a pressure ranging from 2 MPa to 20 MPa for 30 minutes to 3 hours.

9. A method according to claim 3, wherein the diffusion bonding is performed at a temperature ranging from 450°

C. to 900°

C. and under a pressure ranging from 2 MPa to 20 MPa for 30 minutes to 3 hours.

10. A method according to claim 8, wherein the diffusion bonding is performed at a temperature of 700°

C. and under a pressure of 2.0 MPa for 80 minutes.

11. A method according to claim 4, wherein the diffusion bonding for attaching the copper meshes to the aluminum upper and lower covers is performed at a temperature ranging from 300°

C. to 600°

C. and under a pressure ranging from 0.6 MPa to 1.0 MPa for 30 minutes to 4 hours.

12. A method according to claim 5, wherein the diffusion bonding for attaching the copper meshes to the aluminum upper and lower covers is performed at a temperature ranging from 300°

C. to 600°

C. and under a pressure ranging from 0.6 MPa to 1.0 MPa for 30 minutes to 4 hours.

13. A method according to claim 10, wherein the diffusion bonding for attaching the copper meshes to the aluminum upper and lower covers is performed at a temperature of 450°

C. and under a pressure of 0.6 MPa for 80 minutes.

14. A method according to claim 10, wherein the diffusion bonding for attaching the aluminum posts or strips to the aluminum upper and lower covers is performed at a temperature of 550°

C. and under a pressure of 0.6 MPa for 80 minutes.

15. A heat spreader, comprising:

a hollow metallic housing including an upper cover having an inner surface and a lower cover having an inner surface, the upper and lower covers being bonded together along their perimeters defining a cavity;

a capillary structure in a form of metallic meshes bonded to the inner surfaces of the upper and lower covers of the metallic housing;

a plurality of reinforcing members disposed in the cavity and bonded between the inner surfaces of the upper and lower covers of the metallic housing; and

a working fluid received in the cavity;

wherein bonded surfaces between the metallic meshes and the inner surfaces of the metallic housing, the upper cover and the lower cover, and the reinforcing members and the inner surfaces of the metallic housing all are diffusion-bonded interfaces.

16. A heat spreader according to claim 15, wherein the upper cover, the lower cover and the meshes are made from copper, respectively.

17. A heat spreader according to claim 16, wherein the reinforcing members comprise copper posts or copper strips, or a combination thereof.

18. A heat spreader according to claim 15, wherein the metallic material for the upper cover and the lower cover is aluminum and the metallic meshes are copper meshes.

19. A heat spreader according to claim 18, wherein the reinforcing members comprise aluminum posts or aluminum strips, or a combination thereof.

20. A heat spreader according to claim 15, wherein the reinforcing members are bonded between the metallic mesh of the upper cover and the metallic mesh of the lower cover.

21. A heat spreader according to claim 17, wherein the reinforcing members are bonded between the metallic mesh of the upper cover and the metallic mesh of the lower cover.

22. A heat spreader according to claim 15, wherein each of the metallic meshes further has a plurality of openings, and the reinforcing members pass through the openings to connect the inner surfaces of the upper cover and the lower cover.

23. A heat spreader according to claim 17, wherein each of the metallic meshes further has a plurality of openings, and the reinforcing members pass through the openings to connect the inner surfaces of the upper cover and the lower cover.