Magnetic and electric shielding of on-board devices

• US 6,566,596 B1
• Filed: 12/29/1997
• Issued: 05/20/2003
• Est. Priority Date: 12/29/1997
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Askew, Ray
• Primary Examiner(s): Ngo, Hung V.
• Application Number:
  US08/998,615
• Time in Patent Office: 1,968 Days
• Field of Search: 257/659, 257/660, 257/790, 174/35.R, 174/35.MS, 174/51, 174/52.2, 361/816, 361/818, 361/753, 361/752, 361/799, 361/800
• US Class Current: 174/391
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/4911 the connectors being bonded to at least one common bonding area, e.g. daisy chain
• CPC Class Codes: H01L 2224/85399 Material
• CPC Class Codes: H01L 23/3135 Double encapsulation or coating and encapsulation
• CPC Class Codes: H01L 23/552 Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• 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 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 Silicon [Si]
• CPC Class Codes: H01L 2924/01025 Manganese [Mn]
• CPC Class Codes: H01L 2924/01028 Nickel [Ni]
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/0103 Zinc [Zn]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/12032 : Schottky diode
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/1433 : Application-specific integrated circuit [ASIC]
• CPC Class Codes: H01L 2924/16152 : Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/19107 : off-chip wires
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding

Abstract

Improved electromagnetic compatibility for integrated motherboard or device board designs is provided by magnetic shielding, electric shielding, or both integrated into the chip packaging materials. Motherboard emissions may be reduced by use of the shielding. A nonconductive primary and tertiary layer sandwich a high-conductivity metal secondary layer forming a Faraday cage for electric field shielding. A nonconductive primary layer is covered by a tertiary layer formed of a composite having permeable material for magnetic shielding. The tertiary layer formed of a composite could include a high permeability particulate ferrous material. Both the secondary layer and the tertiary layer formed of a composite could be used for both electric and magnetic shielding of chips.

Claims

1. A system encapsulating a device on a device board, comprising:

a nonconductive polymer first layer covering a portion of the device;

an electrically grounded conductive second layer consisting of metal and covering the first layer, the second layer in direct contact with the first layer without an intervening layer between the first and second layers; and

a polymer third layer covering the second layer, the third layer comprising

a polymer material, and

magnetically permeable particles including at least one of ferrous oxide and ferrite.

2. The system of claim 1, wherein the third layer comprises a composite material.

3. The system of claim 1, wherein the third layer comprises epoxy cresol nonvolac polymer.

4. The system of claim 1, wherein the magnetically permeable particles comprise high magnetic permeability material.

5. The system of claim 1, wherein the device comprises an integrated circuit coupled to the device board by bond wires.

6. The system of claim 5, wherein the integrated circuit comprises a silicon die.

7. The system of claim 1, wherein the third layer covers a substantial portion of the first layer.

8. The system of claim 1, wherein the third layer provides magnetic shielding.

9. The system of claim 1, wherein the second layer consists of metal foil.