Integrated circuit heat pipe heat spreader with through mounting holes

• US 20040244951A1
• Filed: 05/07/2004
• Published: 12/09/2004
• Est. Priority Date: 05/12/1999
• Status: Active Grant

• Current Assignee: Aavid Thermalloy LLC (LTI Flexible Products Inc.)
• Original Assignee: Thermal Corporation (Roper Technologies, Inc.)
• Inventors: Rosenfeld, John H., Dussinger, Peter M., Myers, Thomas L., Minnerly, Kenneth L.
• Granted Patent: US 6,896,039 B2
• Time in Patent Office: Days
• US Class Current: 165/104.26
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/1035 Liquid phase sintering
• CPC Class Codes: B22F 3/11 Making porous workpieces or articles
• 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: F28F 2275/04 by brazing brazing heat exchangers B23K1/0012
• CPC Class Codes: H01L 23/4006 with bolts or screws
• 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

A heat pipe with superior heat transfer between the heat pipe and the heat source and heat sink is provided. The heat pipe is held tightly against the heat source by mounting holes which penetrate the structure of the heat pipe but are sealed off from the vapor chamber because they each are located within a sealed structure such as a pillar or the solid layers of the casing surrounding the vapor chamber. Another feature of the heat pipe is the use of a plurality of particles joined together by a brazing compound such that fillets of the brazing compound are formed between adjacent ones of the plurality of particles so as to form a network of capillary passageways between the particles of the wick.

Claims

1. A heat pipe for spreading heat comprising:

a boundary structure including spaced-apart first and second plates that define an enclosed vapor chamber having a capillary structure comprising a plurality of particles joined together by a brazing compound such that fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to form a network of capillary passageways between said particles;

at least one depression formed in said first plate which projects into said vapor chamber and is bonded to said second plate; and

an opening defined through said at least one depression and said second plate wherein said opening is isolated from said vapor chamber.

2. A heat pipe for spreading heat according to claim 1 comprising at least one spacer positioned within said vapor chamber and extending between and contacting said first and second plates.

3. A heat pipe for spreading heat according to claim 1 wherein said spaced-apart first and second plates include confronting interior surfaces;

and

a wick positioned upon said confronting interior surfaces including that portion of the interior surface of said first plate that forms a surface of said depression within said vapor chamber.

4. A heat pipe for spreading heat according to claim 3 wherein said wick is constructed with at least two separate sections of different materials, with one section being located on said first plate interior surface and being formed of a material with higher heat conductivity than sections located on said second plate interior surface.

5. A heat pipe for spreading heat according to claim 1 wherein said depression comprises an annular outer surface that is bonded to a corresponding annular edge surface in said second plate.

6. A heat pipe for spreading heat according to claim 1 wherein said first and second plates each include a peripheral lip located at an edge of said boundary structure which are bonded together.

7. A heat pipe for spreading heat according to claim 1 wherein said plurality of particles comprise a first melting temperature and said brazing compound comprises a second melting temperature that is lower than said first melting temperature.

8. A heat pipe for spreading heat according to claim 1 wherein said brazing compound comprises about sixty-five percent weight copper and thirty-five percent weight gold particles such that said fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to create a network of capillary passageways between said particles.

9. A heat pipe for spreading heat according to claim 1 wherein said fillets are formed by capillary action of said braze compound when in a molten state.

10. A heat pipe for spreading heat according to claim 1 wherein said metal particles are selected from the group consisting of carbon, tungsten, copper, aluminum, magnesium, nickel, gold, silver, aluminum oxide, and beryllium oxide.

11. A heat pipe for spreading heat according to claim 1 wherein said metal particles comprise a shape selected from the group consisting of spherical, oblate spheroid, prolate spheroid, ellipsoid, polygonal, and filament.

12. A heat pipe for spreading heat according to claim 1 wherein said metal particles comprise at least one of copper spheres and oblate copper spheroids having a melting point of about one thousand eighty-three °

C.

13. A heat pipe for spreading heat according to claim 7 wherein said brazing compound comprises six percent by weight of a finely divided copper/gold brazing compound.

14. A heat pipe for spreading heat according to claim 7 wherein said brazing compound is present in the range from about two percent to about ten percent.

15. A heat pipe for spreading heat according to claim 7 wherein said metal particles comprise copper powder comprising particles size in a range from about twenty mesh to about two-hundred mesh.

16. A heat pipe for spreading heat according to claim 7 wherein said braze compound particles comprise about minus three hundred and twenty-five mesh.

17. A heat pipe for spreading heat according to claim 1 wherein said metal particles that are a constituent portion of said braze compound comprise a smaller size than said metal particles.

18. A heat pipe for spreading heat according to claim 1 wherein said braze compound is selected from the group consisting of nickel-based Nicrobrazes, silver/copper brazes, tin/silver, lead/tin, and polymers.

19. A heat pipe for spreading heat according to claim 1 wherein said plurality of metal particles comprise aluminum and magnesium and said brazing compound comprises an aluminum/magnesium intermetallic alloy.

20. A heat pipe for spreading heat comprising:

a boundary structure including spaced-apart first and second plates that define an enclosed vapor chamber having a capillary structure comprising a plurality of particles joined together by a brazing compound such that fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to form a network of capillary passageways between said particles;

at least one depression formed in said first plate which projects into said vapor chamber and is bonded to said second plate;

an opening defined through said first plate depression and said second plate wherein said opening is isolated from said vapor chamber; and

at least one depression formed in said second plate which projects into said vapor chamber and is bonded to said first plate.

21. A heat pipe for spreading heat according to claim 20 wherein said at least one depression formed in said second plate comprises a flat portion that is in contact with an inner surface of said first plate.

22. A heat pipe for spreading heat according to claim 20 wherein said spaced-apart first and second plates include confronting interior surfaces;

and

a wick positioned upon said confronting interior surfaces including that portion of the interior surface of said first plate that forms a surface of said depression within said vapor chamber.

23. A heat pipe for spreading heat according to claim 20 wherein said plurality of particles comprise a first melting temperature and said brazing compound comprises a second melting temperature that is lower than said first melting temperature.

24. A heat pipe for spreading heat according to claim 20 wherein said brazing compound comprises about sixty-five percent weight copper and thirty-five percent weight gold particles such that said fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to create a network of capillary passageways between said particles.

25. A heat pipe for spreading heat according to claim 20 wherein said fillets are formed by capillary action of said braze compound when in a molten state.

26. A heat pipe for spreading heat according to claim 20 wherein said metal particles are selected from the group consisting of carbon, tungsten, copper, aluminum, magnesium, nickel, gold, silver, aluminum oxide, and beryllium oxide.

27. A heat pipe for spreading heat according to claim 20 wherein said metal particles comprise a shape selected from the group consisting of spherical, oblate spheroid, prolate spheroid, ellipsoid, polygonal, and filament.

28. A heat pipe for spreading heat according to claim 20 wherein said metal particles comprise at least one of copper spheres and oblate copper spheroids having a melting point of about one thousand eighty-three °

C.

29. A heat pipe for spreading heat according to claim 24 wherein said brazing compound comprises six percent by weight of a finely divided copper/gold brazing compound.

30. A heat pipe for spreading heat according to claim 24 wherein said brazing compound is present in the range from about two percent to about ten percent.

31. A heat pipe for spreading heat according to claim 24 wherein said metal particles comprise copper powder comprising particles size in a range from about twenty mesh to about two-hundred mesh.

32. A heat pipe for spreading heat according to claim 24 wherein said braze compound particles comprise about minus three hundred and twenty-five mesh.

33. A heat pipe for spreading heat according to claim 20 wherein said metal particles that are a constituent portion of said braze compound comprise a smaller size than said metal particles.

34. A heat pipe for spreading heat according to claim 20 wherein said braze compound is selected from the group consisting of nickel-based Nicrobrazes, silver/copper brazes, tin/silver, lead/tin, and polymers.

35. A heat pipe for spreading heat according to claim 20 wherein said plurality of metal particles comprise aluminum and magnesium and said brazing compound comprises an aluminum/magnesium intermetallic alloy.

36. A heat pipe for spreading heat comprising:

a boundary structure including spaced-apart first and second plates that define an enclosed vapor chamber having a capillary structure comprising a plurality of particles joined together by a brazing compound such that fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to form a network of capillary passageways between said particles;

at least one hollow column positioned within said vapor chamber and sealingly bonded to said first and second plates, having an open first end that opens through said first plate and an open second end that opens through said second plate so as to form at least one mounting hole that is isolated from said vapor chamber.

37. A heat pipe for spreading heat according to claim 36 wherein said spaced-apart first and second plates include confronting interior surfaces;

and

wherein said capillary structure is positioned upon said confronting interior surfaces of said first and second plates the exterior surface of said at least one hollow column disposed within said vapor chamber.

38. A heat pipe for spreading heat comprising:

a boundary structure including a first plate and a second plate arranged in spaced apart relation, each of said plates including interior confronting surfaces and a peripheral lip located at an edge of said boundary structure which are bonded together so as to define an enclosed vapor chamber having a capillary structure comprising a plurality of particles joined together by a brazing compound such that fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to form a network of capillary passageways between said particles;

at least one depression formed in said first plate which projects into said vapor chamber, is spaced from said peripheral lip, and is bonded to said second plate;

an opening defined through said first plate depression and said second plate wherein said depression comprises an annular outer surface that is bonded to a corresponding annular edge surface in said second plate and further wherein said opening is isolated from said vapor chamber;

at least one spacer extending between and contacting said first and second plates; and

wherein said capillary structure is positioned upon said confronting interior surfaces of said first and second plates the exterior surface of said at least one hollow column disposed within said vapor chamber.

39. A heat pipe for spreading heat comprising:

a first plate having a circumferential edge lip bounding an inner surface and at least one hollow column that is integral with said first plate and which projects outwardly relative to said inner surface;

a second plate arranged in spaced apart confronting relation to said first plate and including a circumferential edge lip bounding an inner surface and at least one opening through said second plate, said edge lips of said first and second plates being bonded together so as to define a vapor chamber having a capillary structure comprising a plurality of particles joined together by a brazing compound such that fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to form a network of capillary passageways between said particles;

wherein

said at least one hollow column being bonded at one end to said second plate so as to coaxially align said at least one hollow column with said at least one opening in said second plate thereby to form a mounting hole that extends through said first plate and said second plate and is isolated from said vapor chamber.

40. A heat pipe for spreading heat comprising:

a first plate having a circumferential edge lip bounding an inner surface and at least one depression which projects outwardly relative to said inner surface;

a second plate arranged in spaced apart confronting relation to said first plate and including a circumferential edge lip bounding an inner surface and at least one opening through said second plate, said edge lips of said first and second plates being bonded together so as to define a vapor chamber having a capillary structure comprising a plurality of particles joined together by a brazing compound such that fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to form a network of capillary passageways between said particles;

wherein

said at least one depression has an open ended tubular cross-section and an outer surface, a portion of which outer surface is bonded to said second plate so as to coaxially align said at least one depression with said at least one opening in said second plate thereby to form a mounting hole that extends through said first plate depression and said second plate and is isolated from said vapor chamber.

41. A heat pipe for spreading heat comprising:

a first plate having a circumferential edge lip bounding an inner surface and at least one depression which projects outwardly relative to said inner surface;

a second plate arranged in spaced apart confronting relation to said first plate and including (i) a circumferential edge lip bounding an inner surface, (ii) at least one depression which projects into said vapor chamber and that is bonded to said inner surface of said first plate, and (iii) at least one opening through said second plate, said edge lips of said first and second plates being bonded together so as to define a vapor chamber having a capillary structure comprising a plurality of particles joined together by a brazing compound such that fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to form a network of capillary passageways between said particles;

wherein

said at least one depression in said first plate has a tubular cross-section that opens at a first end and a second end and is bonded to said second plate at said second end so as to coaxially align said at least one first plate depression with said at least one opening in said second plate thereby to form a mounting hole that extends through said first plate depression and said second plate and is isolated from said vapor chamber.