Nano-copper solder for filling thermal vias

• US 9,565,748 B2
• Filed: 10/27/2014
• Issued: 02/07/2017
• Est. Priority Date: 10/28/2013
• Status: Active Grant

• Current Assignee: Multek Technologies Limited
• Original Assignee: Flextronics America LLC (Flextronics International Limited)
• Inventors: Glickman, Michael James
• Primary Examiner(s): Ng, Sherman
• Application Number:
  US14/524,894
• Publication Number:
  US 20150114707A1
• Time in Patent Office: 834 Days
• Field of Search: 174/256, 174/257, 174/262, 174/252
• US Class Current: 1/1
• CPC Class Codes: H05K 1/0206 by printed thermal vias
• CPC Class Codes: H05K 2201/0257 Nanoparticles
• CPC Class Codes: H05K 2201/0266 Size distribution
• CPC Class Codes: H05K 3/0094 Filling or covering plated through-holes or blind plated vias, e.g. for masking or for mechanical reinforcement

Abstract

A method of and device for forming vias on an electronic board (such as a PCB board) comprises forming one or more holes on the electronic board, placing a nanomaterial inside the one or more holes, and forming one or more filled holes on the electronic board. The nanomaterial can be nanocopper, which can be either push/pull into the holes on the electronic board or a combination of push and pull. The push/pull can be performed by using a mechanical device or by a person. A capping layer can be on both side of the via. The vias formed by using the nanomaterials provides a high efficient vertical heat transferring path from one side of the electronic board to the other side of the electronic board.

Claims

1. A method of forming filled holes on an electronic board comprising:

a) forming one or more holes on the electronic board;

b) placing a nanomaterial inside the one or more holes, wherein the nanomaterial comprises a nanomaterial dispersed solution having nanoparticles dispersed in a solvent; and

c) heating the nanomaterial dispersed solution such that the solvent evaporates and the nanoparticles fuse together thereby forming one or more holes on the electronic board filled with fused nanoparticles.

2. The method of claim 1, wherein the electronic board comprises a printed circuit board.

3. The method of claim 1, wherein the nanomaterial comprises nanocopper.

4. The method of claim 1, wherein the one or more holes comprise a through hole.

5. The method of claim 1, further comprising plating a metal on the one or more holes.

6. The method of claim 1, wherein the solvent comprises an alcohol.

7. The method of claim 1, wherein the placing comprising pushing in the nanomaterial.

8. The method of claim 7, wherein the pushing comprises using a sequeegee.

9. The method of claim 1, wherein the placing comprises using a stencil printer.

10. The method of claim 1, wherein the placing comprises pulling in the nanomaterial.

11. The method of claim 10, wherein the pulling comprises using a vacuum table.

12. An electronic board comprising:

a. a body having a nanoparticles filled via extending from a first surface of the body to a second surface of the body, wherein the nanoparticles filled via forms a heat conducting path, further wherein the nanoparticles comprise mixed sizes nanoparticles;

b. a heat generating device coupled to the first surface of the body and thermally connected to the nanoparticles filled via; and

c. a heat sink coupled to the second surface of the body and thermally connected to the nanoparticles filled via.

13. The board of claim 12, wherein the via comprises a body having nanoparticles in a solution distributed substantially throughout the body.

14. The board of claim 12, wherein the via is enclosed by a capping layer.

15. A method of filling a plated through-hole comprising:

a) forming a via hole on a PCB board;

b) cleaning the via hole by using a chemical solution or plasma;

c) forming a layer of metal coating on an outer surface of the via hole;

d) placing a nanomaterial solder into the via hole; and

e) performing a reflow process.

16. The method of claim 15, wherein the via hole is formed by using a mechanical or a laser drill.

17. The method of claim 15, wherein the forming the layer of metal coating uses an electroless copper plating solution.

18. The method of claim 15, further comprising electroplating copper into the via hole.

19. The method of claim 15, wherein the nanomaterial solder comprises a nanocopper solder.

20. The method of claim 15, wherein the placing comprises pushing.

21. The method of claim 15, wherein the placing comprises pulling.

22. The method of claim 15, wherein the reflow comprises sending the PCB board through a lead-free solder reflow oven to melt or fuse the nanomaterial solder.