Heat sink electronic package having compliant pedestal

• US 20070268671A1
• Filed: 05/16/2006
• Published: 11/22/2007
• Est. Priority Date: 05/16/2006
• Status: Active Grant

• Current Assignee: Delphi Technologies Ip Limited (BorgWarner Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Brandenburg, Scott D., Chengalva, Suresh K., Zimmerman, David W.
• Granted Patent: US 7,440,282 B2
• Time in Patent Office: Days
• US Class Current: 361/704
• CPC Class Codes: H01L 21/563 Encapsulation of active face of flip-chip device, e.g. underfilling or underencapsulation of flip-chip, encapsulation preform on chip or mounting substrate
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/73253 Bump and layer connectors
• CPC Class Codes: H01L 23/3675 characterised by the shape of the housing
• CPC Class Codes: H01L 24/72 Detachable connecting means consisting of mechanical auxiliary parts connecting the device, e.g. pressure contacts using springs or clips
• CPC Class Codes: H01L 25/0655 the devices being arranged next to each other
• CPC Class Codes: H01L 25/072 the devices being arranged next to each other
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01027 Cobalt [Co]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01082 Lead [Pb]
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/09701 Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/1305 Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01L 2924/13055 Insulated gate bipolar transistor [IGBT]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/1433 : Application-specific integrated circuit [ASIC]
• CPC Class Codes: H01L 2924/181 : Encapsulation

Abstract

An electronic package is provided for dissipating heat away from electronic devices. The package includes a substrate and electronic devices mounted on the substrate. The package also has a thermally conductive heat sink assembled over the electronic device. The heat sink includes compliant pedestals each having a contact surface for contacting a surface of an electronic device to conduct thermal energy away from the electronic device. The package is held together such that the heat sink is in contact with the surface of an electronic device such that each compliant pedestal applies a compressive force to the surface of the electronic device.

Claims

1. An electronic package comprising:

a substrate;

an electronic device mounted on the substrate, the electronic device having electrical circuitry, a first surface and a second surface oppositely disposed from the first surface;

a thermally conductive heat sink assembled over the electronic device, the heat sink comprising a compliant pedestal comprising a contact surface for contacting the second surface of the electronic device to conduct thermal energy away from the electronic device; and

a holder for holding the contact surface of the heat sink in contact with the second surface of the electronic device such that the compliant pedestal compresses to apply a compressive force to the second surface of the electronic device.

2. The electronic package as defined in claim 1, wherein the package comprises a housing comprising an upper housing member and a lower housing member, wherein the upper housing member comprises the thermally conductive heat sink.

3. The electronic package as defined in claim 2, wherein the lower housing member comprises a case and the upper housing member comprises a cover, and wherein the substrate rests on an inside surface of the case.

4. The electronic package as defined in claim 1, wherein the electronic device is soldered to circuitry on the substrate.

5. The electronic package as defined in claim 1, wherein the substrate comprises a printed circuit board having a plurality of electronic devices mounted on a surface, and the heat sink has a plurality of compliant pedestals pedestals each contacting a different electronic device.

6. The electronic package as defined in claim 1, wherein the electronic device is an integrated circuit chip.

7. The electronic package as defined in claim 6 further comprising an underfill material disposed between the chip and substrate.

8. The electronic package as defined in claim 1, wherein the holder comprises an overmolding material disposed between the heat sink and the substrate.

9. The electronic package as defined in claim 1, wherein the holder comprises an adhesive for holding the heat sink in place such that the contact surface compresses against the second surface of the electronic device.

10. The electronic package as defined in claim 1, wherein the heat sink comprises aluminum.

11. The electronic package as defined in claim 10, wherein the heat sink further comprises copper.

12. The electronic package as defined in claim 1, wherein the thermally conductive heat sink further comprises a reduced thickness groove formed around the pedestal.

13. An electronic package comprising:

a rigid substrate;

an electronic device mounted on the substrate, the electronic device comprising electrical circuitry, a first surface and a second surface oppositely disposed from the first surface; and

a housing for housing the circuit board and the electronic device, said housing comprising an upper housing member and a lower housing member, said upper housing member comprising a thermally conductive material and a compliant pedestal having a contact surface for contacting the second surface of electronic device, such that the compliant pedestal compresses to apply a compressive force to the second surface of the electronic device.

14. The electronic package as defined in claim 13 further comprising a holder for holding the upper housing member onto the lower housing member such that the compliant pedestal compresses against the electronic device.

15. The electronic package as defined in claim 13, wherein the holder comprises an adhesive.

16. The electronic package as defined in claim 13, wherein the holder comprises an overmolding material.

17. The electronic package as defined in claim 13, wherein the electronic device comprises an integrated circuit chip soldered to circuitry on the substrate.

18. The electronic package as defined in claim 17 further comprising an underfill material disposed between the chip and the substrate.

19. A method for assembling an electronic package that conducts thermal energy away from an electronic device, said method comprising the steps of:

providing a substrate;

mounting an electronic device to the substrate, the electronic device having electrical circuitry, a first surface and a second surface oppositely disposed from the first surface;

forming a thermally conductive heat sink having a compliant pedestal with a contact surface;

assembling the heat sink such that the contact surface of the compliant pedestal is in contact with the second surface of the electronic device; and

holding the heat sink such that the contact surface of the compressive pedestal is in compressive contact with the second surface of the electronic device such that the compliant pedestal compresses to provide pressure contact to the electronic device.

20. The method as defined in claim 19 further comprising the step of disposing the substrate in a case of a housing, and attaching the heat sink as a cover onto the case such that the compliant pedestal compresses against the second surface of the electronic device.