Direct chip-cooling through liquid vaporization heat exchange

• US 6,085,831 A
• Filed: 03/03/1999
• Issued: 07/11/2000
• Est. Priority Date: 03/03/1999
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Womac, David J., Iruvanti, Sushumna, DiGiacomo, Giulio
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): MCKINNON, TERRELL L
• Application Number:
  US09/261,345
• Time in Patent Office: 496 Days
• Field of Search: 165/80.3, 165/80.4, 165/104.21, 165/104.26, 165/104.33, 165/185, 257/715, 174/15.2, 361/699, 361/700, 361/385
• US Class Current: 165/104.33
• 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

Abstract

An apparatus for and method of cooling an electronic module comprising a heat sink enclosure placed directly over a chip or substrate in a flip chip package. The heat sink enclosure has a plurality of cooling fins extending from within the cavity of the enclosure. A liquid sealed inside the enclosure is trapped within a thermal transfer means, preferably a metal wick, which sits directly on a chip or substrate. As the chip or substrate heats up, heat is transferred to the thermal transfer means which in turn heats the liquid to its heat of vaporization. The vapors of the liquid rise and condense on the cooling fins and the heat is absorbed by the enclosure and conducted to an outside surface of the enclosure and dissipated. Cooling fins on an exterior surface of the enclosure further reduces the thermal resistance to enhance cooling.

Claims

1. A cooling device for an electronic component comprising

an enclosure having an interior cavity;

a plurality of fins extending within the cavity of said enclosure;

a thermal transfer means for direct attachment to an electronic component;

a liquid inside the cavity of said enclosure permeating said thermal transfer means; and

a seal for attaching and sealing said enclosure to an electronic component forming a liquid tight seal.

2. The device of claim 1 wherein said enclosure is disposed on a periphery of the component and is adapted to draw heat away from the component through said thermal transfer means as said liquid vaporizes from said thermal transfer means.

3. The device of claim 1 wherein the electronic component contains an underfill between a chip and a substrate and wherein said enclosure is disposed on a periphery of the substrate providing a seal, heat is drawn away from the component through said thermal transfer means as said liquid vaporizes.

4. The device of claim 1 wherein said liquid is adapted to be vaporized and condensed on said fins to permeate said thermal transfer means, and wherein heat is absorbed by the enclosure and conducted to an outside surface of said enclosure and dissipated.

5. The device of claim 1 wherein said enclosure comprises a thermally conductive heat sink material.

6. The device of claim 1 wherein said enclosure comprises a thermally conductive material selected from the group consisting of aluminum, copper, aluminum nitride, and silicon carbide.

7. The device of claim 1 wherein said enclosure comprises aluminum.

8. The device of claim 1 wherein said enclosure further comprises a plurality of cooling fins on an exterior surface of said enclosure.

9. The device of claim 1 wherein said thermal transfer means comprises a preform of compacted wire mesh.

10. The device of claim 1 wherein said thermal transfer means comprises a porous, thermally conductive material.

11. The device of claim 1 wherein said liquid comprises a liquid having a boiling point of about room temperature to about 150°

C.

12. The device of claim 1 wherein said liquid comprises an organic liquid.

13. The device of claim 1 wherein said liquid comprises a mixture of at least two organic liquids.

14. The device of claim 1 wherein said liquid comprises water.

15. The device of claim 1 wherein said liquid comprises an aqueous solution having a boiling point of about room temperature to about 150°

C.

16. The device of claim 1 wherein said liquid comprises ammonium hydroxide.

17. The device of claim 1 wherein said seal comprises a sealable O-ring disposed on a periphery of the component corresponding to a periphery of said enclosure.

18. The device of claim 1 wherein said seal comprises a polymer O-ring.

19. The device of claim 1 wherein said seal comprises an elastomer O-ring.

20. The device of claim 1 wherein said enclosure has a plugged opening such that said liquid can be poured into said enclosure subsequent to attaching said enclosure to an electronic package.

21. An electronic module comprising

a substrate;

at least one semiconductor chip mounted on said substrate, said chip having a metal wick disposed on a surface of said chip opposite said substrate;

a liquid filled cooling device mounted over said at least one chip, said cooling device comprising a heat sink enclosure having a plurality of cooling fins extending within said heat sink enclosure; and

a liquid tight seal between said cooling device and said chip,

wherein said chip is adapted to be cooled by the vaporization and condensation of the liquid within said cooling device as heat from said chip travels through the metal wick vaporizing the liquid which rises to condense on the cooling fins, the heat being absorbed by said heat sink enclosure and conducted to an outside surface of said heat sink enclosure.

22. The module of claim 21 wherein said heat sink enclosure further comprises a plurality of cooling fins on an exterior surface of said enclosure.

23. The module of claim 21 wherein said heat sink enclosure comprises a thermally conductive material selected from the group consisting of aluminum, copper, aluminum nitride, and silicon carbide.

24. The module of claim 21 wherein said heat sink enclosure comprises aluminum.

25. The module of claim 21 wherein said metal wick comprises a preform of compacted wire mesh.

26. The module of claim 21 wherein the liquid within said cooling device comprises organic liquids.

27. The module of claim 21 wherein the liquid within said cooling device comprises water.

28. The module of claim 21 wherein the liquid within said cooling device comprises a liquid having a boiling point of about room temperature to about 150°

C.

29. The module of claim 21 wherein the liquid within said cooling device comprises a mixture of at least two organic liquids.

30. The module of claim 21 wherein the liquid within said cooling device comprises ammonium hydroxide.

31. The module of claim 21 wherein the liquid within said cooling device comprises an aqueous solution having a boiling point of about room temperature to about 150°

C.

32. The module of claim 21 wherein said seal comprises a polymeric O-ring having thermosetting properties.

33. The module of claim 21 wherein said seal comprises a polymeric O-ring containing a thermoplastic adhesive.

34. The module of claim 21 wherein said seal elastomeric O-ring having thermosetting properties.

35. The module of claim 21 wherein said seal comprises an elastomeric O-ring containing a thermoplastic adhesive.

36. An improved electronic module having a chip and substrate mechanically and electrically interconnected wherein the improvement comprises

a metal wick disposed directly in said chip on said chip;

and

a heat sink enclosure sealably attached to said chip and said enclosure having a plurality of cooling fins therein sufficiently filled with a working liquid to constantly wet said wick, such that heat generated by said chip is adapted to be transferred to said metal wick, vaporizing said liquid to condense on said cooling fins while said heat sink enclosure absorbs the heat carried by the vapors of said liquid and conducts the heat to an outside surface of said heat sink enclosure.

37. The improved electronic module of claim 36 wherein said heat sink enclosure further comprises a plurality of cooling fins on an exterior surface of said heat sink enclosure.

38. A method of cooling a chip in an electronic module comprising the steps of:

providing an electronic module comprising a substrate and a chip mechanically and electrically interconnected;

providing a metal wick;

providing a cooling device comprising a heat sink enclosure having a plurality of cooling fins extending within said enclosure and a portal;

placing said metal wick directly on said chip on said chip;

sealably attaching said cooling device to said module; and

sufficiently filling the enclosure with a working liquid such that said wick is wetted and soaked by said liquid,

wherein activation of said electronic module produces heat, the heat is transferred to said metal wick vaporizing said liquid forming vapors which rise and condense on said cooling fins, and wherein the heat is absorbed by the heat sink enclosure to cool said chip and conducted to an outside surface of said heat sink enclosure.

39. The method of claim 38 wherein said step of attaching said cooling device to said module comprises

providing a thermosetting O-ring;

placing said O-ring on a periphery of said chip;

applying the heat sink enclosure to said chip such that contact is made with said O-ring to produce a seal around a perimeter of said O-ring; and

curing said O-ring at an appropriate temperature and a length of time such that a liquid tight seal is produced in the heat sink enclosure.

40. The method of claim 38 wherein said thermosetting O-ring further comprises a thermoplastic adhesive.

41. The method of claim 38 wherein said step of attaching said cooling device to said module comprises

providing a thermosetting O-ring;

placing said O-ring on a periphery of said substrate;

applying the heat sink enclosure to said substrate such that contact is made with said O-ring to produce a seal around a perimeter of said O-ring; and

curing said O-ring at an appropriate temperature and a length of time such that a liquid tight seal is produced in the heat sink enclosure.

42. The method of claim 40 wherein said thermosetting O-ring further comprises a thermoplastic adhesive.

43. The method of claim 38 wherein said metal wick comprises a preform of compacted wire mesh.

44. The method of claim 38 wherein said heat sink enclosure comprises a thermally conductive material selected from the group consisting of aluminum, copper, aluminum nitride, and silicon carbide.

45. The method of claim 38 wherein said heat sink enclosure further comprises a plurality of cooling fins on an exterior surface of said heat sink enclosure.

46. The method of claim 38 wherein said liquid comprises an organic liquid.

47. The method of claim 38 wherein said liquid comprises water.

48. The method of claim 38 wherein said liquid comprises ammonium hydroxide.

49. The method of claim 38 wherein said liquid comprises a liquid having a boiling point of about room temperature to about 150°

C.

50. The method of claim 38 wherein said liquid comprises a mixture of at least two organic liquids.

51. The method of claim 38 wherein said liquid comprises an aqueous solution having a boiling point of about room temperature to about 150°

C.