Shielding apparatus for non-conductive electronic circuit packages

• US 5,313,371 A
• Filed: 01/14/1993
• Issued: 05/17/1994
• Est. Priority Date: 03/04/1991
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Sieben, David J., Knecht, Thomas A., Mancini, Brian M., Achille, Jean-Robert
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): SPARKS, DONALD ALAN
• Application Number:
  US08/004,775
• Time in Patent Office: 488 Days
• Field of Search: 29/25.35, 174/35 R, 174/35 MS, 228/121, 228/123, 228/124, 228/214, 228/215, 361/816, 361/818, 427/239, 427/250, 427/282, 427/287, 455/154, 455/158, 455/183
• US Class Current: 361/818
• CPC Class Codes: H01L 2924/1617 Cavity coating
• CPC Class Codes: H05K 9/0039 Galvanic coupling of ground layer on printed circuit board [PCB] to conductive casing printed shielding conductors, ground planes or power planes for reduction of cross-talk or noise in printed circuits H05K1/0218
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

A shielding apparatus for use with a non-conductive package has an insulated lid (102) which is retained in contact with a substrate (104) for holding an electrical circuit. The shielding apparatus includes a first conductive flash (201) deposited on the interior surface of the insulated lid (102), to produce a substantially contiguous conduction layer, and a second conductive flash (203) deposited over a film (110) disposed on the edge of the insulated lid (102), to produce a partially contiguous conduction layer. The shielding apparatus also includes a layer (108) for affixing the insulated lid (102) to the substrate (104), to produce an enclosure for isolating the electrical circuit from extraneous radio frequency (RF) energy.

Claims

1. A shielding apparatus for an insulating lid having an edge and an interior surface, the edge being retained in contact with a substrate having the electrical circuit disposed thereon, the shielding apparatus comprising:

a film disposed on the edge of the insulated lid;

a first conductive flash selectively disposed on the first interior surface, such that a substantially non-uniform, contiguous conduction layer is disposed thereon;

a second conductive flash selectively disposed on said film, to produce a conduction layer which partially covers said film; and

means, disposed on the substrate and substantially aligned with said film disposed on the edge of the insulated lid, for hermetically affixing the insulated lid to the substrate, whereby a hermetically sealed enclosure for isolating the electrical circuit from extraneous radio frequency energy is produced.

2. A shielding apparatus in accordance with claim 1, further comprising a conductive area disposed on the substrate and forming an electrical ground plane for the electrical circuit.

3. A shielding apparatus in accordance with claim 2, further comprising means for joining said conductive area to said enclosure.

4. A shielding apparatus in accordance with claim 1, wherein said film further comprises a conductive material.

5. A shielding apparatus in accordance with claim 1, wherein said first and said second conductive flash further comprises at least one metallic composition which is wettable with said film.

6. A shielding apparatus in accordance with claim 1, wherein said first and said second conductive flash further comprises at least one metallic composition which is non-wettable with said film.

7. A shielding apparatus for an electric circuit, which apparatus includes an insulated lid and an insulated substrate, the insulated substrate having the electrical circuit disposed thereon and having a first surface and a second surface, the insulated lid having a first interior surface and an edge, the electrical circuit including a conductive area disposed on the first surface, the shielding apparatus comprising:

a film disposed on the edge of the insulated lid;

a first conductive flash selectively disposed on the first interior surface, such that a substantially non-uniform, contiguous conduction layer is produced thereon;

a first conductive flash selectively disposed on said film, to produce a conduction layer which partially covers said film;

means, disposed peripherally about the electrical circuit on the first surface and substantially aligned with said film disposed on the edge of the insulated lid, for affixing the insulated lid to the substrate, whereby a hermetically-sealed enclosure for isolating the electrical circuit from extraneous radio frequency energy is produced; and

means for connecting the conductive area to said hermetically-sealed enclosure, said means for connecting further comprising;

a first via extending through the substrate within a boundary defined by the conductive area on the substrate, said first via having a first interior surface which is substantially coated with a conductive material, whereby the conductive area is electrically connected to the first via;

a second via extending through the substrate and substantially aligned with said means for affixing, said second via having a second interior surface which is substantially coated with a conductive material, whereby said hermetically sealed enclosure is electrically connected to the second via; and

a conductive strip disposed on the second surface extending from the first via to the second via, whereby the first via is electrically connected to the second via.

8. A shielding apparatus in accordance with claim 7, wherein said film further comprises a conductive material.

9. A shielding apparatus in accordance with claim 7, wherein said first and said second conductive flash further comprises at least one metallic composition which is wettable with said film.

10. A shielding apparatus in accordance with claim 7, wherein said first and said second conductive flash further comprises at least one metallic composition which is non-wettable with said film.

11. A method of shielding an electrical circuit using an apparatus which includes an insulated lid having an edge and an interior surface, the edge being retained in contact with a substrate having the electrical circuit disposed thereon, the method comprising the steps of:

depositing a conductive solder on the edge of the insulated lid;

selectively depositing a first conductive flash on the interior surface, such that a substantially non-uniform, contiguous conduction layer is disposed therein;

depositing a second conductive flash on said film to produce a partially contiguous conduction layer; and

hermetically affixing the insulated lid to the substrate, whereby a hermetically sealed enclosure for isolating the electrical circuit from extraneous radio frequency (RF) energy is produced.