Conductive cooling of a heat-generating electronic component using a cured-in-place, thermally-conductive interlayer having a filler of controlled particle size

• US 5,781,412 A
• Filed: 11/22/1996
• Issued: 07/14/1998
• Est. Priority Date: 11/22/1996
• Status: Expired due to Term

• Current Assignee: Parker Intangibles LLC (Parker-Hannifin Corporation)
• Original Assignee: Parker-Hannifin Corporation
• Inventors: de Sorgo, Miksa
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): CHERVINSKY, BORIS LEO
• Application Number:
  US08/755,081
• Time in Patent Office: 599 Days
• Field of Search: 361/704, 361/706, 361/708, 361/707, 361/715, 361/720, 361/722, 361/723, 361/705, 257/702, 257/706, 257/717, 165/185, 174/16.3
• US Class Current: 361/704
• CPC Class Codes: H01L 23/42 Fillings or auxiliary members in containers or encapsulations selected or arranged to facilitate heating or cooling
• CPC Class Codes: H01L 23/433 Auxiliary members in containers characterised by their shape, e.g. pistons
• 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: H05K 1/0203 Cooling of mounted components H05K1/0272 takes precedence
• CPC Class Codes: H05K 2201/0209 Inorganic, non-metallic particles
• CPC Class Codes: H05K 3/305 Affixing by adhesive

Abstract

Conductive cooling of a heat-generating electronic component disposable in spaced-apart adjacency with a surface of a thermal dissipation member to define a gap of predetermined width therebetween. A curable composition is provided as formed of an electrically-insulating polymeric binder having thermally-conductive, electrically-insulating filler particles dispersed therein. At least a portion of the filler particles is of a maximum average diameter about equal to the predetermined width of the gap. A layer of the composition is disposable in conductive heat transfer contact with the electronic component and the surface of the thermal dissipation member, and is cured to form an interlayer within the gap. At least a portion of the filler particles of the specified maximum average diameter each substantially directly contact the electronic component and the surface of the thermal dissipation member to establish thermally-conductive pathways effective to transfer heat from the electronic component to the heat dissipation member.

Claims

1. A method of conductively cooling a heat-generating electronic component disposable in spaced-apart adjacency with a surface of a thermal dissipation member to define a gap of a predetermined width therebetween, said method comprising the steps of:

(a) providing a curable, fluent composition comprising an electrically-insulating polymeric binder having thermally-conductive, electrically-insulating filler particles dispersed therein, said particles having a thermal conductivity of between about 25-50 W/m-K and at least a portion thereof being of a maximum average diameter about equal to the predetermined width of the gap;

(b) providing a layer of said composition disposable in conductive heat transfer contact with the electronic component and the surface of the thermal dissipation member; and

(c) curing said layer of said composition to form an interlayer within the gap having a continuous phase of said binder and a dispersed phase of said filler particles, at least a portion of said filler particles of said maximum average diameter each substantially directly contacting the electronic component and the surface of the thermal dissipation member to establish thermally- conductive pathways effective to transfer heat from the electronic component to the heat dissipation member.

2. The method of claim 1 wherein the thermal dissipation member is a heat sink or a circuit board.

3. The method of claim 1 wherein said layer of said composition is provided in step (b) as applied in a fluent state on the surface of the thermal dissipation member, and wherein said method further comprises an additional step after step (b) of disposing said electronic component on said layer.

4. The method of claim 1 wherein said layer of said composition is provided in step (b) as applied in a fluent state to an outer surface of said electronic component, and wherein said method further comprises an additional step after step (b) of disposing said thermal dissipation member on said layer.

5. The method of claim 1 further comprising an additional step prior to step (b) of disposing the electronic component in said spaced-apart adjacency with the surface of the thermal dissipation member, and wherein said layer is provided in step (b) by injecting the composition in a fluent state between said electronic component and the surface of the thermal dissipation member.

6. The method of claim 1 wherein said curable composition is provided in step (a) as comprising a first and a second reactive component each containing a portion of said filler particles, said method further comprising an additional step prior to step (b) of admixing said first and said second reactive component.

7. The method of claim 6 wherein said first reactive component comprises a silanol-terminated polymer and said second reactive component comprises a cross-linking agent, said reactive components combining when admixed to form a room- temperature vulcanizing (RTV) silicone elastomer forming said polymeric binder of said composition.

8. The method of claim 6 further comprising an additional step prior to step (b) of disposing the electronic component in said spaced-apart adjacency with the surface of the thermal dissipation member, and wherein said layer is provided in step (b) by injecting the admixed first and second reactive between the electronic component and the surface of the thermal dissipation member.

10. The method of claim 1 wherein said filler particles comprise graphitic boron nitride.

12. The method of claim 1 wherein said polymeric binder of said curable composition comprises a room temperature vulcanizing (RTV) silicone elastomer.

13. The method of claim 1 wherein said curable composition is provided as comprising about 50 to 55% by weight of said filler particles.

15. The method of claim 1 wherein the average diameter of the portion of said particles of said curable composition provided as having a maximum average diameter substantially equal to the predetermined width of the gap is at least about 5 mils (125 microns).

9. The method of claim I wherein said filler particles of said curable composition are selected from the group consisting of particles of boron nitride, aluminum oxide, aluminum nitride, magnesium oxide, zinc oxide, silicon carbide, beryllium oxide, and mixtures thereof.

11. The method of claim I wherein said polymeric binder of said curable composition is selected from the group consisting of polyurethanes, polyimides, nylons, polyamides, polyesters, polyolefins, epoxies, polyetheretherketones, silicone elastomers, fluorosilicone elastomers, thermoplastic elastomers, acrylic resins, and copolymers and blends thereof.

14. The method of claim I wherein the width of the gap between the electronic component and the surface of the thermal dissipation member is at least about 3 mils (75 microns).

16. A conductively-cooled electrical assembly comprising:

a thermal dissipation member having an outer surface;

a heat-generating electronic component disposed in spaced-apart adjacency with said surface of said thermal dissipation member to define a gap of a predetermined width therebetween; and

a cured-in-place interlayer disposed within said gap in conductive heat transfer contact with said electronic component and the surface of said thermal dissipation member, said interlayer comprising a continuous phase of an electrically-insulating polymeric binder and a dispersed phase of thermally-conductive, electrically-insulating filler particles dispersed therein said continuous phase, said particles having a thermal conductivity of between about 25-50 W/m-K and at least a portion thereof being of a maximum average diameter about equal to the predetermined width of the gap and substantially directly contacting said electronic component and the surface of said thermal dissipation member to establish heat transfer pathways from said electronic component to said thermal dissipation member.

17. The electrical assembly of claim 16 wherein said thermal dissipation member is a heat sink or a circuit board.

18. The electrical assembly of claim 16 wherein said filler particles of said interlayer are selected from the group consisting of particles of boron nitride, aluminum oxide, aluminum nitride, magnesium oxide, zinc oxide, silicon carbide, beryllium oxide, and mixtures thereof.

19. The electrical assembly of claim 16 wherein said filler particles of said interlayer comprise graphitic boron nitride.

20. The electrical assembly of claim 16 wherein said polymeric binder of said interlayer is selected from the group consisting of polyurethanes, polyimides, nylons, polyamides, polyesters, polyolefins, epoxies, polyetheretherketones, silicone elastomers, fluorosilicone elastomers, thermoplastic elastomers, acrylic resins, and copolymers and blends thereof.

21. The electrical assembly of claim 16 wherein said polymeric binder of said interlayer comprises a room temperature vulcanizing (RTV) silicone elastomer.

22. The electrical assembly of claim 16 wherein said interlayer comprises about 50 to 55% by weight of said filler particles.

23. The electrical assembly of claim 16 wherein the width of said gap between said electronic component and the surface of said thermal dissipation member is at least about 3 mils (75 microns).

24. The electrical assembly of claim 16 wherein the average diameter of the portion of said particles of said interlayer having a maximum average diameter substantially equal to the predetermined width of said gap is at least about 5 mils (125 microns).