Method and system for controlling radio frequency radiation in microelectronic packages using heat dissipation structures

• US 6,075,700 A
• Filed: 02/02/1999
• Issued: 06/13/2000
• Est. Priority Date: 02/02/1999
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Houghton, Christopher Lee, Brench, Colin Edward
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): CHERVINSKY, BORIS LEO
• Application Number:
  US09/241,351
• Time in Patent Office: 497 Days
• Field of Search: 361/687-689, 361/698-700, 361/704, 361/707, 361/709, 361/714, 361/715, 361/719-721, 361/816, 361/818, 257/707, 257/706, 257/713-719, 165/80.2-80.4, 165/18.5, 174/15.1, 174/15.2, 174/16.3
• US Class Current: 361/704
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/32188 the layer connector connecting to a bonding area protruding from the surface of the item
• CPC Class Codes: H01L 2224/32225 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 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 23/3675 characterised by the shape of the housing
• CPC Class Codes: H01L 23/552 Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 23/66 High-frequency adaptations
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/73 Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• 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 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15153 : the die mounting substrate comprising a recess for hosting the device
• CPC Class Codes: H01L 2924/1517 : Multilayer substrate
• CPC Class Codes: H01L 2924/15192 : Resurf arrangement of the internal vias
• CPC Class Codes: H01L 2924/15311 : being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/15312 : being a pin array, e.g. PGA
• CPC Class Codes: H01L 2924/1532 : the connection portion being formed on the die mounting surface of the substrate
• CPC Class Codes: H01L 2924/16195 : Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/19107 : off-chip wires
• CPC Class Codes: H01L 2924/30107 : Inductance
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H05K 1/0218 : by printed shielding conductors, ground planes or power plane H05K1/0236 takes precedence
• CPC Class Codes: H05K 1/0243 : Printed circuits associated with mounted high frequency components
• CPC Class Codes: H05K 1/181 : associated with surface mounted components
• CPC Class Codes: H05K 2201/10704 : Pin grid array [PGA]
• CPC Class Codes: H05K 2201/10734 : Ball grid array [BGA]; Bump grid array
• 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

Abstract

A method and apparatus are disclosed for attenuating RF noise produced by electronic systems by providing low RF impedance shorting of heat dissipating structures, such as heat sinks, to PCB reference planes. The RF impedance shorting path uses existing package pins with dedicated electrical paths through the package to the bottom surface of the heat sink. Such an arrangement provides very low RF impedance because of the minimal length and resistance of the shorting path, and also provides minimal disruption of the PCB design rules and tolerances by using existing package leads.

Claims

1. An apparatus for reducing radiation from an electronic device comprising:

a package connecting an electronic circuit to a circuit board via a plurality of connectors;

a conductive heat dissipative heat spreader structure on an outside surface of the package; and

the package providing at least one electrical connection between the conductive heat dissipative heat spreader structure and the circuit board using at least one of the plurality of connectors;

wherein the heat spreader is connected to the package by a brazing process, the heat spreader having threaded studs brazed thereon, and a heat sink connected by nuts to the heat spreader.

2. The apparatus of claim 1 wherein further a thermally conductive compliant material is disposed between the heat sink and the heat spreader.

3. An apparatus for reducing radiation from an electronic device comprising:

a package connecting an electronic circuit to a circuit board via a plurality of essentially identical connectors;

a conductive heat spreader connected to an outside surface of the package by a brazing process, the heat spreader having threaded studs brazed thereon, and a heat sink connected by nuts to the heat spreader; and

the package providing at least one electrical connection between the heat sink to at least one of the plurality of connectors.

4. The apparatus of claim 3 wherein further a thermally conductive compliant material is disposed between the heat sink and the heat spreader.