Conformal electromagnetic interference shielding film

Patent metadata

Field	Value
Publication number	US-12069845-B2
Application number	US-202217660789-A
Country	US
Kind code	B2
Filing date	Apr 26, 2022
Priority date	Apr 26, 2022
Publication date	Aug 20, 2024
Grant date	Aug 20, 2024

Abstract

Provided is a conformal electromagnetic interference (EMI) shielding film including a thermal-forming film layer and an electrically conductive film layer. The thermal-forming film layer is configured to conformally coat over one or more electronic components mounted on a substrate with application of heat. The electrically conductive film layer is formed on an opposite side of the thermal-forming film layer from the substrate and has a plurality of voids that are configured to deform during the application of heat and allow the electrically conductive film layer to conform together with the thermal-forming film layer.

First claim

The invention claimed is:

1. A conformal electromagnetic interference (EMI) shielding film, comprising: a thermal-forming film layer configured to conformally coat over one or more electronic components mounted on a substrate with application of heat; and an electrically conductive film layer formed on an opposite side of the thermal-forming film layer from the substrate and having a plurality of voids that are configured to deform during the application of heat and allow the electrically conductive film layer to conform together with the thermal-forming film layer, wherein in a first area of the electrically conductive film layer, the plurality of voids are formed at a first density, and in a second area of the electrically conductive film layer, the plurality of voids are formed at a second density different density than the first density.

2. The conformal EMI shield of claim 1 , wherein in a first area of the electrically conductive film layer, the plurality of voids are formed at a first size, and in a second area of the electrically conductive film layer, the plurality of voids are formed at a second size different than the first size.

3. The conformal EMI shield of claim 1 , wherein before the application of heat, the plurality of voids include circular voids.

4. The conformal EMI shield of claim 1 , wherein before the application of heat, the plurality of voids include oblong voids.

5. The conformal EMI shield of claim 1 , wherein the electrically conductive film layer is woven.

6. The conformal EMI shield of claim 1 , wherein the electrically conductive film layer includes at least one of copper, aluminum, gold, silver, nickel, tin, zinc, magnesium, iron, or alloys thereof.

7. The conformal EMI shield of claim 1 , wherein the thermal-forming film layer includes at least one of polyethylene terephthalate, ethylene vinyl acetate, polyvinyl chloride, polystyrene, acrylonitrile butadiene styrene, acrylic, cellulose acetate butyrate, polycarbonate, polysulfone, or combinations thereof.

8. The conformal EMI shield of claim 1 , further comprising a thermal spreading layer configured to conduct heat.

9. A method for manufacturing a conformal electromagnetic interference (EMI) shielding film, the method comprising: forming a thermal-forming film layer; forming an electrically conductive film layer on the thermal-forming film layer with a plurality of voids; and applying heat to conformally coat the thermal-forming film layer over one or more electronic components mounted on a substrate and deform the plurality of voids to allow the electrically conductive film layer formed on an opposite side of the thermal-forming film layer from the substrate to conform together with the thermal-forming film layer, further comprising forming the plurality of voids in a first area of the electrically conductive film layer at a first density, and forming the plurality of voids in a second area of the electrically conductive film layer at a second density different than the first density.

10. The method of claim 9 , further comprising forming the plurality of voids in a first area of the electrically conductive film layer at a first size, and forming the plurality of voids in a second area of the electrically conductive film layer at a second size different than the first size.

11. The method of claim 9 , wherein before the application of heat, the plurality of voids include circular voids.

12. The method of claim 9 , wherein before the application of heat, the plurality of voids include oblong voids.

13. The method of claim 9 , wherein the electrically conductive film layer is woven.

14. The method of claim 9 , further comprising preforming a composite of the thermal-forming film layer and the electrically conductive film layer to an intermediate shape before applying the preformed composite to the substrate and applying the heat.

15. The method of claim 9 , wherein forming the electrically conductive film layer includes metallic ink printing, physical vapor deposition, or lamination.

16. The method of claim 9 , further comprising constraining the conformal EMI shielding film at one or more locations against the substrate or the one or more electronic components before applying the heat.

17. The method of claim 9 , further comprising applying positive or negative pressure to the conformal EMI shielding film while or after applying the heat.

18. An electromagnetic interference (EMI) shielded circuit board, comprising:
a circuit board including one or more electronic components mounted on a substrate; and
a conformal EMI shielding film including:
a thermal-forming film layer configured to conformally coat over the one or more electronic components with application of heat; and
an electrically conductive film layer formed on an opposite side of the thermal-forming film layer from the substrate and having a plurality of voids that are configured to deform during the application of heat and allow the electrically conductive film layer to conform together with the thermal-forming film layer.

Assignees

• Microsoft Technology Licensing Llc

Inventors

• Lee Jaejin
• Dan Bo
• Li Han

Classifications

• H05K2203/1322

  Encapsulation comprising more than one layer · CPC title

• H05K3/284

  for encapsulating mounted components (H05K1/185 takes precedence) · CPC title

• H05K1/0216

  Reduction of cross-talk, noise or electromagnetic interference (grounding H05K1/0215) · CPC title

• H05K9/0088 Primary

  comprising a plurality of shielding layers; combining different shielding material structure · CPC title

• H05K9/0086 Primary

  comprising a single discontinuous metallic layer on an electrically insulating supporting structure, e.g. metal grid, perforated metal foil, film, aggregated flakes, sintering · CPC title