Heat sink electronic package having compliant pedestal

• US 7,440,282 B2
• Filed: 05/16/2006
• Issued: 10/21/2008
• 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., Zimmerman, David W., Chengalva, Suresh K.
• Primary Examiner(s): Gandhi, Jayprakash N
• Assistant Examiner(s): Smith, Courtney L
• Application Number:
  US11/434,644
• Publication Number:
  US 20070268671A1
• Time in Patent Office: 889 Days
• Field of Search: 361/704, 361/707, 361/710, 361/715, 361/719, 361/760, 361/730, 361/736, 257/E23.101, 257/E23.104, 257/E21.503, 165/80.3, 165/185, 174/16.3
• 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 having opposed first and second surfaces mounted on the substrate;

a holder for rigidly fixing said substrate and the first surface of said electronic device;

a thermally conductive heat sink assembled over the electronic device, said heat sink including a substantially rigid base portion and at least one compliant pedestal integrally formed with said base portion, said pedestal defining a substantially flat contact surface portion and a thinned portion resiliently interconnecting said base and contact surface portions,

wherein said contact surface portion is continuously resiliently biased against said second surface of said electronic device to form a thermally conductive path therebetween.

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 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. The electronic package of claim 1, wherein said base portion, contact surface portion and thinned portion of said heat sink are commonly formed from thermally conductive material.

14. The electronic package of claim 13, wherein said thermally conductive material comprises aluminum.

15. The electronic package of claim 13, wherein said thermally conductive material comprises aluminum layered with a copper alloy.