Advanced microelectronic heat dissipation package and method for its manufacture

• US 20060000584A1
• Filed: 06/01/2005
• Published: 01/05/2006
• Est. Priority Date: 08/28/2001
• Status: Abandoned Application

• Current Assignee: Advanced Materials Technology Pte Limited
• Original Assignee: Advanced Materials Technology Pte Limited
• Inventors: Tan, Lye-King, German, Randall M., Johnson, John
• Application Number:
  US11/141,886
• Publication Number:
  US 20060000584A1
• Time in Patent Office: Days
• US Class Current: 165/104.330
• CPC Class Codes: F28D 15/0275 Arrangements for coupling heat-pipes together or with other structures, e.g. with base blocks; Heat pipe cores
• CPC Class Codes: F28D 2015/0225 Microheat pipes
• CPC Class Codes: H01L 21/4871 Bases, plates or heatsinks
• 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 29/49353 Heat pipe device making

Abstract

Heat dissipation during the operation of integrated circuit chips is an old problem that continues to get worse. The present invention significantly ameliorates this by placing an embedded heat pipe directly beneath the chip. Using powder injection molding, the lower portion of the package is formed first as an initial green part which includes one or more cavities. The latter are then lined with a feedstock that is designed to produce a porous material after sintering, at which time a working fluid is introduced into the porous cavities and sealed, thereby forming one or more heat pipes located directly below the chip. The latter is then sealed inside an enclosure. During operation, heat generated by the chip is efficiently transferred to points outside the enclosure. A process for manufacturing the structure is also described.

Claims

1. A process to manufacture a heat pipe, comprising:

providing a first feedstock, having a first volume, that further comprises first particles, having a mean diameter less than about 30 microns, uniformly dispersed within a first binder, said first particles occupying between about 50 and 65% of said first volume;

providing a second feedstock, having a second volume, that further comprises second particles, having a mean diameter between about 40 and 200 microns, uniformly dispersed within a second binder, said second particles occupying between about 30 and 40% of said second volume;

molding said first feedstock around a first insert to form a green body;

then removing said first insert from the green body thereby forming, in the green body, a cavity having one closed end and one open end;

adding a second insert to said cavity;

filling said cavity with said second feedstock;

removing all binding materials from said green body and from said second feedstock inside said cavity, thereby forming a first skeleton within which is a second skeleton that is more porous than said first skeleton;

sintering said first and second skeletons, thereby forming a dense body that includes an interior wick;

introducing a working fluid into said wick; and

then sealing said open end, thereby forming said heat pipe.

2. The process described in claim 1 wherein said first particles are selected from the group consisting of copper, aluminum, tungsten, tungsten-copper, kovar, stainless steel, and nickel alloys.

3. The process described in claim 1 wherein said second particles are selected from the group consisting of copper, aluminum, tungsten, tungsten-copper, kovar, stainless steel, and nickel alloys.

4. The process described in claim 1 wherein said second particles are removed from within said cavity during the step of sintering the skeletons.

5. The process described in claim 1 wherein the step of removing said first insert from the green body further comprises destruction of said first insert.

6. The process described in claim 1 wherein said first insert is selected from the group consisting of bronze, steel, and alumina.

7. The process described in claim 1 wherein said first insert may be reused after the termination of said process.

8. The process described in claim 1 wherein said working fluid is selected from the group consisting of water, ammonia, acetone, and alcohol.

9. A process to manufacture a heat pipe, comprising:

providing a feedstock, having a volume, that further comprises particles, having a mean diameter less than about 30 microns, uniformly dispersed within a binder, said particles occupying between about 50 and 65% of said volume;

molding said feedstock around an insert to form a green body;

then removing said insert from the green body thereby forming, in the green body, a cavity having one closed end and one open end and dimensions less than about 1,000 microns;

removing all binding materials from said green body, thereby forming a skeleton within which is a micro-channel capable of functioning as a wick;

sintering said skeleton thereby forming a dense body that includes said wick;

introducing a working fluid into said wick; and

then sealing said open end, thereby forming said heat pipe.

10. A process to manufacture a package containing a heat pipe, comprising:

providing a first feedstock, having a first volume, that further comprises first particles, having a mean diameter less than about 30 microns, uniformly dispersed within a first binder, said first particles occupying between about 50 and 65% of said first volume;

providing a second feedstock, having a second volume, that further comprises second particles, having a mean diameter between about 40 and 200 microns, uniformly dispersed within a second binder, said second particles occupying between about 30 and 40% of said second volume;

molding said first feedstock around a first insert to form a green body;

then removing said first insert from the green body thereby forming, in the green body, a cavity having one closed end and one open end;

adding a second insert to said cavity;

filling said cavity with said second feedstock;

removing all binding materials from said green body and from said second feedstock inside said cavity, thereby forming a first skeleton within which is a second skeleton that is more porous than said first skeleton;

sintering said first and second skeletons, thereby forming a dense body that includes an interior wick;

introducing a working fluid into said wick;

then sealing said open end, thereby forming said heat pipe;

on a surface of said package, forming an open enclosure that is overlapped by said heat pipe;

then mounting said integrated circuit chip inside said enclosure on said surface using a high thermal conductivity medium; and

then sealing said enclosure.

11. The process described in claim 10 wherein said first particles are selected from the group consisting of copper, aluminum, tungsten, tungsten-copper, kovar, stainless steel, and nickel alloys.

12. The process described in claim 10 wherein said second particles are selected from the group consisting of copper, aluminum, tungsten, tungsten-copper, kovar, stainless steel, and nickel alloys.

13. The process described in claim 10 wherein said second particles are removed from within said cavity during the step of sintering the skeletons.

14. The process described in claim 10 wherein the step of removing said first insert from the green body further comprises destruction of said first insert.

15. The process described in claim 10 wherein said first insert is selected from the group consisting of bronze, steel, and alumina.

16. The process described in claim 10 wherein said first insert may be reused after the termination of said process.

17. The process described in claim 10 wherein said working fluid is selected from the group consisting of water, ammonia, acetone, and alcohol.

19. The process described in claim 10 wherein said high thermal conductivity medium is helium.

20. The process described in claim 10 further comprising forming, within said enclosure, contact pads and leads, connected to said contact pads, that terminate outside said enclosure.

21. The process described in claim 10 wherein a high thermal conductivity material is sealed inside said enclosure together with said chip.

18. A process to manufacture a package containing a heat pipe, comprising:

providing a feedstock, having a volume, that further comprises particles, having a mean diameter less than about 30 microns, uniformly dispersed within a binder, said particles occupying between about 50 and 65% of said volume;

molding said feedstock around an insert to form a green body;

then removing said insert from the green body thereby forming, in the green body, a cavity having one closed end and one open end and dimensions less than about 1,000 microns;

removing all binding materials from said green body, thereby forming a skeleton within which is a micro-channel capable of functioning as a wick;

sintering said skeleton thereby forming a dense body that includes said wick;

introducing a working fluid into said wick;

then sealing said open end, thereby forming said heat pipe;

on a surface of said package, forming an open enclosure that is overlapped by said heat pipe;

then mounting said integrated circuit chip inside said enclosure on said surface using a high thermal conductivity medium; and

then sealing said enclosure.

22. A heat pipe, for use with integrated circuits, comprising:

a solid body wherein is located a fully enclosed cavity whose diameter exceeds 1,000 microns, said cavity being lined with a porous material; and

a working fluid in said cavity.

23. The heat pipe described in claim 22 wherein said solid body is selected from the group consisting of copper, aluminum, tungsten, tungsten-copper, kovar, stainless steel, and nickel alloys.

24. The heat pipe described in claim 22 wherein said porous material is selected from the group consisting of copper, aluminum, tungsten, tungsten-copper, kovar, stainless steel, and nickel alloys.

25. The heat pipe described in claim 22 wherein said working fluid is selected from the group consisting of water, ammonia, acetone, and alcohol.

26. A package for an integrated circuit chip, comprising:

a fully enclosed cavity within a solid body having an upper surface;

said cavity being lined with a porous material and containing a working fluid;

on said upper surface, overlapped by said cavity, an enclosure within which said integrated circuit chip has been sealed; and

said integrated chip being mounted on said upper surface through a high thermal conductivity medium.

27. The package described in claim 26 wherein said body is selected from the group consisting of copper, aluminum, tungsten, tungsten-copper, kovar, stainless steel, and nickel alloys.

28. The package described in claim 26 wherein said porous material is selected from the group consisting of copper, aluminum, tungsten, tungsten-copper, kovar, stainless steel, and nickel alloys.

29. The package described in claim 26 wherein said cavity is between about 2 and 8 mm wide, between about 2 and 5 mm deep, and between about 12 and 60 mm long.

30. The package described in claim 26 further comprising contact pads, within said enclosure, and leads, connected to said pads, that terminate outside said enclosure.

31. The package described in claim 26 wherein a high thermal conductivity material is sealed inside said enclosure together with said chip.