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Soft-Metal Interfaced Heatsinks for Air-Cooled Electronics Packages

IP.com Disclosure Number: IPCOM000119463D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 1 page(s) / 41K

Publishing Venue

IBM

Related People

Kang, SK: AUTHOR [+2]

Abstract

Disclosed is a structure of an air-cooled heatsink for electronics packages mounted on a printed wiring board. The sketches in Figure 1 are the said heatsink mounted on a tape-automated-bonding (TAB) package as an example. The main body of the heatsink 10 is first cut out from a copper alloy sheet. A shallow dimple 11 at the center of the heatsink 10 and two arches 12 at the ends of the heatsink 10 are then stamped. The area of dimple 11 is slightly larger than the surface area of the TAB package 13 and the dimple 11 is filled with soft metals, such as lead/tin alloy 14. The two arches 12 provide the necessary compression force to the heatsink 10 to ensure a good contact with the package 13 and flexibility to avoid extra mechanical stresses created by the bending of the printed wiring board (PWB) 15.

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This is the abbreviated version, containing approximately 100% of the total text.

Soft-Metal Interfaced Heatsinks for Air-Cooled Electronics Packages

      Disclosed is a structure of an air-cooled heatsink for
electronics packages mounted on a printed wiring board.  The sketches
in Figure 1 are the said heatsink mounted on a tape-automated-bonding
(TAB) package as an example.  The main body of the heatsink 10 is
first cut out from a copper alloy sheet.  A shallow dimple 11 at the
center of the heatsink 10 and two arches 12 at the ends of the
heatsink 10 are then stamped.  The area of dimple 11 is slightly
larger than the surface area of the TAB package 13 and the dimple 11
is filled with soft metals, such as lead/tin alloy 14. The two arches
12 provide the necessary compression force to the heatsink 10 to
ensure a good contact with the package 13 and flexibility to avoid
extra mechanical stresses created by the bending of the printed
wiring board (PWB) 15.  The heatsink 10 is mounted to the PWB 15
either by soldering or riveting.  The thermal contact resistance from
the package 13 to the heatsink 10 is generally low because of the
softness of the soft metals 14 and the compression force induced by
the two arches 12.  The thermal contact resistance can further be
reduced by reflowing the soft metals 14 inside the dimple 11 such
that the air gap between the soft metals 14 and the packages 13, and
the thickness of the soft-metal layer between the package 13 and the
heatsink 10 are diminished to minimum.

      Disclosed anonymously.