Electromagnetic shielding structure

• US 7,498,656 B2
• Filed: 03/31/2004
• Issued: 03/03/2009
• Est. Priority Date: 10/15/2002
• Status: Active Grant

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Zhang, Ligang, Smith, Kevin G., Pietruszynski, David, Thomsen, Axel
• Primary Examiner(s): Gurley; Lynne
• Assistant Examiner(s): IM, JUNGHWA M
• Application Number:
  US10/813,886
• Publication Number:
  US 20040178472A1
• Time in Patent Office: 1,798 Days
• Field of Search: 257/531, 257/528, 257/277, 257/E23.114, 257/E23.125, 257/E21.022, 257/686, 257/422, 257/685, 257/777, 257/778
• US Class Current: 257/531
• CPC Class Codes: H01F 2017/008 Electric or magnetic shielding of printed inductances
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 23/552 Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 23/645 Inductive arrangements H01L23/647, H01L23/66 take precedence
• 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 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/15311 being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding

Abstract

An improved electromagnetic shielding structure has been discovered. In one embodiment of the invention, an apparatus includes an inductor and an electrically conductive enclosure that electromagnetically shields the inductor. The electrically conductive enclosure has an aperture at least as large as the inductor. The aperture is substantially centered around a projected surface of the inductor. The apparatus may include one or more electrically conductive links extending across the aperture and electrically coupled to the electrically conductive enclosure. The electrically conductive links reduce an effect of electromagnetic signals external to the electrically conductive enclosure on the inductor.

Claims

1. An apparatus comprising:

an inductor;

an electrically conductive enclosure electromagnetically shielding the inductor, the electrically conductive enclosure having an aperture at least as large as the inductor, the aperture being substantially centered around a projected surface of the inductor;

a plurality of electrically conductive links, individual ones of the plurality of electrically conductive links extending across the aperture; and

at least one additional electrically conductive link,

wherein the plurality of electrically conductive links are electrically coupled to the electrically conductive enclosure and are electrically coupled to each other at a first location within the aperture, and

wherein individual ones of the plurality of electrically conductive links are coupled to each other at least at a second location within the aperture by the at least one additional electrically conductive link, the at least one additional electrically conductive link being within the aperture.

2. The apparatus, as recited in claim 1, wherein the aperture is substantially parallel to a plane of current flow in the inductor.

3. The apparatus, as recited in claim 1,

wherein the plurality of electrically conductive links reduce an effect of electromagnetic signals external to the electrically conductive enclosure on the inductor.

4. The apparatus, as recited in claim 1, wherein the plurality of electrically conductive links and the at least one additional electrically conductive link reduce coupling in the inductor from external sources by approximately 6 dB.

5. The apparatus, as recited in claim 1, wherein each of the plurality of electrically conductive links and the at least one additional electrically conductive link are approximately 5 μ

m wide.

6. The apparatus, as recited in claim 1, wherein the plurality of electrically conductive links and the at least one additional electrically conductive link are formed in one or more traditional integrated circuit layers.

7. The apparatus, as recited in claim 1, wherein the electrically conductive enclosure includes a top plate, a bottom plate, and sidewalls.

8. The apparatus, as recited in claim 7, wherein the aperture is formed in the bottom plate.

9. The apparatus, as recited in claim 7, wherein the bottom plate is formed in one or more integrated circuit metal layers.

10. The apparatus, as recited in claim 7, wherein the top plate is formed in a metal layer.

11. The apparatus, as recited in claim 7, wherein the top plate is formed in a redistribution layer.

12. The apparatus, as recited in claim 7, wherein the top plate is formed in a package substrate.

13. The apparatus, as recited in claim 1, wherein the inductor is formed at least partially in one or more metal layers of an integrated circuit die thicker than others of the metal layers.

14. The apparatus, as recited in claim 1, wherein the inductor is formed at least partially in one or more redistribution layers formed on an integrated circuit die.

15. The apparatus, as recited in claim 1, wherein the inductor is formed on an integrated circuit die.

16. The apparatus, as recited in claim 15, wherein a conductor forming the inductor is 10 μ

m wide.

17. The apparatus, as recited in claim 15, wherein the aperture and the inductor are effectively spaced at least 10.25 μ

m apart.

18. The apparatus, as recited in claim 1, wherein the aperture is formed in an electrically conductive plate of the electrically conductive enclosure.

19. The apparatus, as recited in claim 1, wherein the aperture has an approximate diameter determined by adding an approximate outer diameter of the inductor to an approximate inner diameter of the inductor.

20. The apparatus, as recited in claim 1, wherein the at least one additional electrically conductive link intersects individual ones of the plurality of electrically conductive links at ninety degree angles.

21. The apparatus, as recited in claim 1, wherein the first location is in the center of the aperture and the second location is between the center of the aperture and the perimeter of the aperture.

22. The apparatus, as recited in claim 1, wherein individual ones of the plurality of electrically conductive links are coupled to at least one portion of the electrically conductive enclosure at a third location, the third location being at the perimeter of the aperture.