Thermal management of electronic components

• US 9,224,672 B1
• Filed: 12/17/2014
• Issued: 12/29/2015
• Est. Priority Date: 12/17/2014
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Pykri, Lasse, Saarinen, Ilkka J., Koskinen, Matti T.
• Primary Examiner(s): Ho, Tu-Tu
• Application Number:
  US14/573,304
• Time in Patent Office: 377 Days
• Field of Search: 257/712, 257/719, 257/530
• US Class Current: 1/1
• CPC Class Codes: H01L 2224/16227 the bump connector connecting to a bond pad of the item
• CPC Class Codes: H01L 2224/32145 the bodies being stacked
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2225/06568 the devices decreasing in size, e.g. pyramidical stack
• CPC Class Codes: H01L 2225/1023 the support being an insulating substrate
• CPC Class Codes: H01L 2225/1058 Bump or bump-like electrical connections, e.g. balls, pillars, posts
• CPC Class Codes: H01L 2225/1094 Thermal management, e.g. cooling
• CPC Class Codes: H01L 23/04 characterised by the shape of the container or parts, e.g. caps, walls
• CPC Class Codes: H01L 23/043 the container being a hollow construction and having a conductive base as a mounting as well as a lead for the semiconductor body
• CPC Class Codes: H01L 23/367 Cooling facilitated by shape of device H01L23/38, H01L23/40, H01L23/42, H01L23/44, H01L23/46 take precedence
• CPC Class Codes: H01L 23/3677 Wire-like or pin-like cooling fins or heat sinks
• CPC Class Codes: H01L 23/373 Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
• CPC Class Codes: H01L 23/3733 having a heterogeneous or anisotropic structure, e.g. powder or fibres in a matrix, wire mesh, porous structures H01L23/3732, H01L23/3737 take precedence
• CPC Class Codes: H01L 23/3737 Organic materials with or without a thermoconductive filler
• CPC Class Codes: H01L 23/552 Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 24/16 of an individual bump connector
• CPC Class Codes: H01L 24/45 : of an individual wire connector
• CPC Class Codes: H01L 24/48 : of an individual wire connector
• CPC Class Codes: H01L 24/73 : Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 25/03 : all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
• CPC Class Codes: H01L 25/105 : the devices being of a type provided for in group H01L27/00
• 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 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/15331 : being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/181 : Encapsulation

Abstract

An electronic device comprises a multi-layer printed circuit board. On the printed circuit board there is installed electronic components and a metal frame that encloses at least part of the electronic components. A layer of bonded anisotropic conductive film is disposed on the frame and the electronic components. The layer connects thermally a sheet of metal foil on the frame and on the electronic components. The sheet of metal foil covers the electronic component and the metal frame.

Claims

1. An electronic device comprising:

a multi-layer printed circuit board;

at least one first electronic component installed on the printed circuit board;

a first metal frame installed on the printed circuit board, the first metal frame enclosing the at least one electronic component; and

a first layer of bonded anisotropic conductive film on the first metal frame and the at least one first electronic component connecting thermally a sheet of metal foil on the first frame and on the at least first one electronic component, the sheet covering the at least one first electronic component and the first metal frame.

2. The electronic device according to claim 1, wherein the at least one first electronic component comprises an integrated circuit.

3. The electronic device according to claim 2, wherein the integrated circuit comprises a chip package comprising at least two package layers covered by an electrically insulating cured resin mold.

4. The electronic device according to claim 1, wherein the first frame is suitable for radio-frequency shielding.

5. The electronic device according to claim 1, wherein the first layer of bonded anisotropic conductive film comprises at least one of copper nickel and tin particles.

6. The electronic device according to claim 1, the electronic device further comprising:

at least one second electronic component installed on the printed circuit board;

a second metal frame installed on the printed circuit board, the second metal frame enclosing the at least one second electronic component; and

a second layer of bonded anisotropic conductive film on the second frame and the at least one second electronic component connecting thermally a sheet of metal foil on the second frame and on the at least one second electronic component, the sheet also covering the at least one second electronic component and the first frame.

7. The electronic device according to claim 6, wherein a height of the second metal frame is different from the height of the first metal frame.

8. The electronic device according to claim 6, wherein the at least one second electronic component comprises an integrated circuit.

9. The electronic device according to claim 6, wherein the integrated circuit comprises a chip package comprising at least two package layers covered by an electrically insulating cured resin mold.

10. The electronic device according to claim 6, wherein the second frame is suitable for radio-frequency shielding.

11. The electronic device according to claim 1, the electronic device further comprising:

at least one third electronic component;

a third layer of bonded anisotropic conductive film thermally connecting the sheet of metal foil on the at least one third electronic component, the sheet also covering the at least one third electronic component.

12. The electronic device according to claim 11, wherein the at least one third electronic component comprises an integrated circuit.

13. The electronic device according to claim 12, wherein the integrated circuit comprises a chip package.

14. The electronic device according to claim 12, wherein the integrated circuit comprises a flip chip.

15. The electronic device according to claim 1, wherein the sheet is thermally connected to a heat sink.

16. The electronic device according to claim 15, wherein the heat sink comprises at least one copper layer of the printed circuit board.

17. The electronic device according to claim 16, wherein the sheet is attached with a spot of bonded anisotropic conductive film on a thermal via of the printed circuit board, the thermal via being thermally connected to a copper layer of the multi-layer printed circuit board.

18. The electronic device according to claim 1, wherein the sheet is made of at least one of copper foil, aluminum foil and alpaca foil, the foil having a thickness between 5 μ

m and 125 μ

m.

19. A method, comprising:

adding a first layer of anisotropic conductive film on a metal frame and at least one electronic component, the metal frame enclosing the electronic component, the metal frame and the electronic component being attached on a printed circuit board, wherein a sheet of metal foil is arranged on the first layer of anisotropic conductive film;

applying a first pressure on the sheet in an area covering the at least one electronic component to fix the sheet on the first layer of anisotropic conductive film on the at least one electronic component; and

applying a second pressure on the sheet in an area covering the metal frame to fix the sheet on the first layer of anisotropic conductive film on the metal frame, thereby bonding the first layer of anisotropic conductive film to form a thermal connection of the at least one electronic component to the metal frame via the sheet of metal foil.

20. A computer program stored on a computer readable medium, the computer program comprising code adapted to cause the following when executed on a data-processing system:

adding a first layer of anisotropic conductive film on a metal frame and at least one electronic component, the metal frame enclosing the electronic component, the metal frame and the electronic component being attached on a printed circuit board, wherein a sheet of metal foil is arranged on the first layer of anisotropic conductive film;

applying a first pressure on the sheet in an area covering the at least one electronic component to fix the sheet on the first layer of anisotropic conductive film on the at least one electronic component; and

applying a second pressure on the sheet in an area covering the metal frame to fix the sheet on the first layer of anisotropic conductive film on the metal frame, thereby bonding the first layer of anisotropic conductive film to form a thermal connection of the at least one electronic component to the metal frame via the sheet of metal foil.