Board-level EMI shield with enhanced thermal dissipation

• US 6,744,640 B2
• Filed: 04/10/2002
• Issued: 06/01/2004
• Est. Priority Date: 04/10/2002
• Status: Expired due to Term

• Current Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Original Assignee: Gore Enterprise Holdings Incorporated (W.L. Gore and Associates)
• Inventors: Reis, Bradley, Candy, William
• Primary Examiner(s): Martin, David
• Assistant Examiner(s): Levi, Dameon E.
• Application Number:
  US10/120,251
• Publication Number:
  US 20030193794A1
• Time in Patent Office: 783 Days
• Field of Search: 361/800, 361/816, 361/818, 174/35.R, 174/35.GC
• US Class Current: 361/818
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/73253 Bump and layer connectors
• CPC Class Codes: H01L 23/552 Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01087 Francium [Fr]
• CPC Class Codes: H01L 2924/16152 Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H01L 2924/16153 Cap enclosing a plurality of side-by-side cavities [e.g. E-shaped cap]
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding
• CPC Class Codes: H05K 7/20445 the coupling element being an additional piece, e.g. thermal standoff
• CPC Class Codes: H05K 9/0026 integrally formed from metal sheet
• CPC Class Codes: H05K 9/0028 with retainers or specific soldering features
• CPC Class Codes: H05K 9/003 made from non-conductive materials comprising an electro-conductive coating H05K9/0031 takes precedence
• CPC Class Codes: H05K 9/0035 with retainers mounted beforehand on the PCB, e.g. clips

Abstract

A substrate having at least one electrical component disposed thereon; a plurality of discrete electrically conductive fastening units disposed in a pattern on the substrate surrounding the at least one electrical component; a board-level electromagnetic interference (EMI) shield comprising an electrically conductive layer; a plurality of apertures formed in the board-level EMI shield such that the apertures correspond to the pattern of the electrically conductive fastening units; with at least one thermally conductive interface (TCI) material disposed over the at least one electrical component; and wherein the electrically conductive layer of the board-level EMI shield is in electrical contact with at least one electrically conductive fastening unit.

Claims

1. An apparatus comprising:

(a) a substrate having at least one electrical component disposed thereon;

(b) a plurality of discrete electrically conductive fastening units disposed in a pattern on said substrate surrounding said at least one electrical component;

(c) a board-level electromagnetic interference (EMI) shield comprising an electrically conductive layer;

(d) a plurality of apertures formed in said board-level EMI shield such that said apertures correspond to said pattern of said electrically conductive fastening units;

(e) at least one thermally conductive interface (TCI) material disposed over said at least one electrical component; and

(f) wherein said electrically conductive layer of said board-level EMI shield is in electrical contact with at least one said electrically conductive fastening units.

2. An apparatus as defined in claim 1 wherein at least one of said apertures has a contact region and wherein said electrically conductive layer of said board-level electromagnetic interference (EMI) shield is deflectable to the extent necessary to allow said contact region to engage and retain at least one of said electrically conductive fastening units.

3. An apparatus as defined in claim 1 wherein at least one of said electrically conductive fastening units is a solder sphere.

4. An apparatus as defined in claim 1 wherein said board-level electromagnetic interference (EMI) shield further comprises a dielectric material layer.

5. An apparatus as defined in claim 4 wherein said dielectric material layer has an outer surface, and wherein said electrically conductive layer is disposed on said outer surface of said dielectric material layer.

6. An apparatus as defined in claim 1 wherein said electrically conductive layer is selected from the group consisting of aluminum, tin, gold, nickel, silver, copper and combinations and alloys thereof.

7. An apparatus as defined in claim 1 wherein said electrically conductive layer is foil.

8. An apparatus as defined in claim 1 wherein said substrate has a plurality of electrical components and said board-level electromagnetic interference (EMI) shield further comprises a plurality of compartments adapted to cover said plurality of electrical components.

9. An apparatus as defined in claim 1 wherein said at least one TCI material comprises an elastomer filled with thermally conductive particles.

10. An apparatus as defined in claim 1 further comprising a heat sink.

11. An apparatus as defined in claim 10 wherein said board-level electromagnetic interference (EMI) shield comprises at least one opening and wherein said at least one thermally conductive interface (TCI) material at least partially passes through said at least one opening and makes physical contact with both said heat sink and said at least one component.

12. An apparatus as defined in claim 11 further comprising an electrically conductive surface on said heat sink and an EMI gasket, wherein said EMI gasket is in electrical contact with said electrically conductive layer of said board-level EMI shield and said electrically conductive surface of said heat sink, and substantially surrounding said at least one opening.

13. An apparatus as defined in claim 11 further comprising an electrically conductive surface on said heat sink, and wherein said at least one thermally conductive interface (TCI) material substantially covers said at least one opening, and wherein said at least one TCI material is also electrically conductive, and wherein said electrically conductive TCI material is in electrical contact with said electrically conductive surface on said heat sink and said electrically conductive layer of said board-level electromagnetic interference (EMI) shield.

14. An apparatus comprising:

(a) a substrate having at least one electrical component disposed thereon;

(b) a plurality of solder spheres disposed on said substrate surrounding said at least one electrical component;

(c) a board-level electromagnetic interference (EMI) shield comprising at least one compartment adapted to cover said at least one electrical component, said board-level EMI shield further comprising an electrically conductive layer;

(d) at least one thermally conductive interface (TCI) material disposed over said at least one electrical component;

(e) a heat sink disposed over said at least one TCI material;

(f) wherein said electrically conductive layer of said board-level EMI shield is in electrical contact with at least one of said solder spheres, and wherein said board-level EMI shield and said solder spheres combine to limit electromagnetic radiation from entering or exiting said at least one compartment; and

(g) wherein said heat sink and said at least one TCI material combine to dissipate heat from said at least one electrical component.

15. A board-level electromagnetic interference (EMI) shield for a substrate having at least one electrical component disposed thereon and a plurality of discrete electrically conductive fastening units disposed in a pattern on the substrate surrounding the at least one electronic component, the board-level EMI shield comprising:

(a) an electrically conductive layer;

(b) a plurality of apertures formed in said board-level EMI shield such that said apertures correspond to the pattern of the electrically conductive fastening units;

(c) at least one thermally conductive interface (TCI) material attached to said board-level EMI shield;

(d) wherein at least one of said apertures has a contact region and wherein said electrically conductive layer of said board-level EMI shield at said contact region of said aperture are deflectable to the extent necessary to allow said contact region to engage and retain at least one of said electrically conductive fastening units; and

(e) wherein said electrically conductive layer of said EMI shield at said contact region is adapted to make electrical contact with at least one said electrically conductive fastening unit.