Semi-solid metal injection methods for electronic assembly thermal interface

• US 7,169,650 B2
• Filed: 07/30/2004
• Issued: 01/30/2007
• Est. Priority Date: 03/12/2002
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Koning, Paul A., Rinella, Agostino C.
• Primary Examiner(s): Whitehead, Jr.; Carl
• Assistant Examiner(s): Dolan; Jennifer M.
• Application Number:
  US10/909,206
• Publication Number:
  US 20050006757A1
• Time in Patent Office: 914 Days
• Field of Search: 438/118, 438/119, 438/122, 257/E23.107, 257/E23.109
• US Class Current: 438/119
• CPC Class Codes: B22D 17/007 Semi-solid pressure die casting
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/73253 Bump and layer connectors
• 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 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/10253 Silicon [Si]

Abstract

To accommodate high power densities associated with high performance integrated circuits, an integrated circuit package includes a heat-dissipating structure in which heat is dissipated from a surface of a die to an integrated heat spreader (IHS) through a high capacity thermal interface formed of metal that has been injected in a semi-solid state. In one embodiment, vacuum and a shear-controlled viscosity enable semi-solid metallic material to fill a narrow chamber between the die surface and a specially shaped mold plate that doubles as an IHS, without inducing voids in the solidified metal. In another embodiment, an injection machine is disclosed. Methods of fabrication, as well as application of the package to an electronic assembly and to an electronic system, are also described.

Claims

1. A method comprising:

positioning a die adjacent to a plate;

flowing a thermally conductive thixotropic metal material between the die and the plate; and

applying vacuum to the thermally conductive material.

2. The method recited in claim 1, wherein the thermally conductive material comprises an alloy from the group consisting of tin, lead, silver, gold, nickel, copper, antimony, zinc, indium, bismuth, and gallium.

3. The method recited in claim 1, wherein the thermally conductive material comprises an alloy of approximately 63% tin and 37% lead.

4. The method recited in claim 1 and further comprising before flowing:

agitating the thermally conductive material.

5. A method comprising:

positioning a die adjacent to a plate;

flowing a thermally conductive thixotropic metal alloy material between the die and the plate; and

applying vacuum to the thermally conductive material.

6. The method recited in claim 5 wherein the thermally conductive material comprises an alloy from the group consisting of tin, lead, silver, gold, nickel, copper, antimony, zinc, indium, bismuth, and gallium.

7. The method recited in claim 5 wherein the thermally conductive material comprises an alloy of approximately 63% tin and 37% lead.

8. The method recited in claim 5 and further comprising before flowing:

agitating the thermally conductive material.

9. A method comprising:

positioning a die adjacent to a plate, the die having a front surface comprising a plurality of terminals, and the die further having a back surface, which is adjacent to the plate; and

flowing a thermally conductive thixotropic metal alloy material between the die and the plate;

wherein the plate comprises an inlet, an outlet, an inlet ramp, and an outlet ramp, and wherein the inlet ramp extends from the inlet to the die, and wherein the outlet ramp extends from the die to the outlet.

10. The method recited in claim 9 wherein the plate comprises one of copper or a copper alloy.

11. The method recited in claim 9 wherein the plate comprises diamond.

12. The method recited in claim 9 wherein the plate comprises a channel having a dimension substantially equal to a dimension of the die.

13. The method recited in claim 9,

wherein the plate comprises a substantially planar upper surface and a lower surface comprising a die-fitting area having equivalent dimensions to those of the die, and having a pair of boundaries in physical contact with the die;

wherein the inlet is in the upper surface;

wherein the outlet is in the upper surface;

wherein the outlet ramp extends downwardly from the inlet to the die-fitting area and in physical contact with both the inlet and the die-fitting area; and

wherein the outlet ramp extends upwardly from the die-fitting area to the outlet and in physical contact with both the die-fitting area and the outlet.

14. The method recited in claim 13, wherein the plate further comprises a channel having a dimension substantially equal to a dimension of the die-fitting area.

15. The method recited in claim 13, wherein the plate is formed of material comprising one of copper, a copper alloy, and diamond.

16. The method recited in claim 13, wherein the die comprises a processor.

17. A method comprising:

positioning a die adjacent to a plate;

flowing a thermally conductive material from one of a liquid metallic material and a semi-solid metallic material between the die and the plate; and

applying vacuum to the thermally conductive material.

18. The method recited in claim 17, wherein the thermally conductive material comprises an alloy from the group consisting of tin, lead, silver, gold, nickel, copper, antimony, zinc, indium, bismuth, and gallium.

19. The method recited in claim 17 wherein the plate comprises an inlet, an outlet, an inlet ramp, and an outlet ramp, and wherein the inlet ramp extends from the inlet to the die, and wherein the outlet ramp extends from the die to the outlet.

20. A method comprising:

positioning a die adjacent to a plate;

flowing a thermally conductive material from one of a liquid metallic alloy material and a semi-solid metallic alloy material between the die and the plate; and

applying vacuum to the thermally conductive material.

21. The method recited in claim 20, wherein the thermally conductive material comprises an alloy from the group consisting of tin, lead, silver, gold, nickel, copper, antimony, zinc, indium, bismuth, and gallium.

22. The method recited in claim 20 wherein the plate comprises an inlet, an outlet, an inlet ramp, and an outlet ramp, and wherein the inlet ramp extends from the inlet to the die, and wherein the outlet ramp extends from the die to the outlet.

23. A method comprising:

positioning a die adjacent to a plate, the die having a front surface comprising a plurality of terminals, and the die further having a back surface, which is adjacent to the plate; and

flowing a thermally conductive material from one of a liquid metallic alloy material and a semi-solid metallic alloy material between the die and the plate;

wherein the plate comprises an inlet, an outlet, an inlet ramp, and an outlet ramp, wherein the inlet ramp extends from the inlet to the die, and wherein the outlet ramp extends from the die to the outlet.

24. The method recited in claim 23, wherein the thermally conductive material comprises an alloy of approximately 63% tin and 37% lead.

25. The method recited in claim 23, wherein the die comprises a processor.