CONDUCTION COOLING FOR CIRCUIT BOARDS

• US 20200135608A1
• Filed: 10/26/2018
• Published: 04/30/2020
• Est. Priority Date: 10/26/2018
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: KELLEY, Douglas Patrick
• Granted Patent: US 10,720,372 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 21/4882 Assembly of heatsink parts
• CPC Class Codes: H01L 23/147 Semiconductor insulating substrates semiconductor conductive substrates H01L23/4926
• CPC Class Codes: H01L 23/367 Cooling facilitated by shape of device H01L23/38, H01L23/40, H01L23/42, H01L23/44, H01L23/46 take precedence
• CPC Class Codes: H01L 23/3735 Laminates or multilayers, e.g. direct bond copper ceramic substrates
• CPC Class Codes: H05K 7/20372 Cryogenic cooling; Nitrogen liquid cooling
• CPC Class Codes: H05K 7/20509 Multiple-component heat spreaders; Multi-component heat-conducting support plates; Multi-component non-closed heat-conducting structures
• CPC Class Codes: H05K 7/20809 within server blades for removing heat from heat source
• CPC Class Codes: H10N 60/80 Constructional details

Abstract

Disclosed is a cooling assembly for circuit boards. In one embodiment, the assembly includes a circuit board that is thermally and physically coupled to a heat spreader by a thermal interface. In one configuration, the circuit board is formed from a semiconductor material and includes a first board surface on which integrated circuits are mounted and a second board surface opposite the first board surface. The heat spreader is formed from a thermally conductive material and includes a plurality of vanes that are spaced apart from one another. The thermal interface is coupled between at least one area of the second board surface of the circuit board and a contact area of each of the plurality of vanes. Heat generated by the integrated circuits is conducted from at least one integrated circuit to the plurality of vanes of the heat spreader through the circuit board and the thermal interface.

Claims

1. An apparatus comprising:

at least one integrated circuit;

a circuit board formed from a semiconductor material and comprising a first board surface on which the at least one integrated circuit is mounted and a second board surface opposite the first board surface;

a heat spreader of a thermally conductive material and comprising a plurality of vanes that are spaced apart from one another; and

a thermal interface coupled between at least one area of the second board surface of the circuit board and a contact area of each of the plurality of vanes, wherein heat generated by the at least one integrated circuit is conducted from the at least one integrated circuit to the plurality of vanes of the heat spreader through the circuit board and the thermal interface.

2. The apparatus of claim 1 wherein the contact area for each of the plurality of vanes is the only portion of the thermal interface in contact with the heat spreader.

3. The apparatus of claim 2 wherein the thermal interface is an elongated strip that resides exclusively within a central portion of the second board surface that extends along a first axis.

4. The apparatus of claim 3 wherein the plurality of vanes of the heat spreader are substantially parallel with one another and a second axis that is substantially orthogonal to the first axis.

5. The apparatus of claim 4 wherein thermal interface is at least 75% indium.

6. The apparatus of claim 5 wherein the elongated strip is linear.

7. The apparatus of claim 1 wherein the at least one integrated circuit is formed from the semiconductor material.

8. The apparatus of claim 7 wherein the semiconductor material is silicon.

9. The apparatus of claim 1 further comprising a first chassis wall and a second chassis wall wherein each of the plurality of vanes extends between the first chassis wall and the second chassis wall and are thermally coupled to both of the first chassis wall and the second chassis wall.

10. The apparatus of claim 9 comprising at least one tube and wherein:

the first chassis wall has a first opening, and the second chassis wall has a second opening; and

the first opening and the second opening are in fluid communication with one another via the at least one tube.

11. The apparatus of claim 1 wherein the heat spreader is at least 99.99% aluminum.

12. The apparatus of claim 11 wherein the thermal interface is at least 75% indium.

13. The apparatus of claim 1 wherein:

the at least one integrated circuit is formed from the semiconductor material;

the semiconductor material is silicon;

the heat spreader is at least 99.99% aluminum;

the contact area for each of the plurality of vanes is the only portion of the thermal interface in contact with the heat spreader.

14. The apparatus of claim 13 wherein the thermal interface resides exclusively within a central portion of the second board surface that extends along a first axis.

15. A method comprising:

providing a circuit board formed from a semiconductor material and comprising a first board surface on which at least one integrated circuit is mounted and a second board surface opposite the first board surface;

providing a first thermal interface subsection on a portion of the second board surface of the circuit board;

providing a heat spreader of a thermally conductive material and comprising a plurality of vanes that are spaced apart from one another by a plurality of slots and a second thermal interface subsection on the heat spreader; and

bonding the first thermal interface subsection to the second thermal interface subsection to form a thermal interface, wherein heat generated by the at least one integrated circuit is conducted from the at least one integrated circuit to the plurality of vanes of the heat spreader through the circuit board and the thermal interface.

16. The method of claim 15 wherein the first thermal interface subsection and the second thermal interface subsection are at least 75% indium.

17. The method of claim 15 wherein the thermal interface is coupled between at least one area of the second board surface of the circuit board and a contact area of each of the plurality of vanes;

and the contact area for each of the plurality of vanes is the only portion of the thermal interface in contact with the heat spreader.

18. The method of claim 17 wherein the thermal interface is an elongated strip that resides exclusively within a central portion of the second board surface that extends along a first axis.

19. The method of claim 15 wherein:

the at least one integrated circuit is formed from the semiconductor material;

the semiconductor material is silicon; and

the thermal interface is an elongated strip that resides exclusively within a central portion of the second board surface that extends along a first axis.

20. The method of claim 15 wherein the semiconductor material is silicon.