Browse Prior Art Database

Extrusion Integral Heatsink for Air-Cooled Non-Hermetic Packages

IP.com Disclosure Number: IPCOM000119761D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 43K

Publishing Venue

IBM

Related People

Mak, AW: AUTHOR [+3]

Abstract

Disclosed is a one-piece, integrated cap-heatsink fabricated by extruding an aluminum alloy to net dimensions. The design incorporates both a seal flange for non-hermetic sealing to a ceramic chip carrier, as well as high aspect ratio fins for air-cooled applications.

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Extrusion Integral Heatsink for Air-Cooled Non-Hermetic Packages

      Disclosed is a one-piece, integrated cap-heatsink fabricated by
extruding an aluminum alloy to net dimensions.  The design
incorporates both a seal flange for non-hermetic sealing to a ceramic
chip carrier, as well as high aspect ratio fins for air-cooled
applications.

      The design offers improved thermal performance by eliminating
interface resistance at the cap-heatsink interface normally
encountered with two-piece designs. Aspect ratios as high as 10:1 can
be achieved from the extrusion process to enhance package cooling.
The number of extruded fins can be tailored to the application
conditions. The figure shows a typical cross section of an integral
cap-heatsink:  the sealing flange "A" can be made to conform to
available sealing areas on the perimeter of the chip carrier.  Also,
the desired aspect ratio can be achieved by proper selection of the
height "B" and fin width "C". Surface "D" offers a threefold
advantage over open-fin designs:  greater structural rigidity; less
pressure drop from inlet to exit in the case of parallel flow; and
large surface area for manufacturing serialization.

      The design can be manufactured in high volume at costs
comparable to die casting with better dimensional control and without
the inherent problems of die casting, such as porosity and
distortion.

      Disclosed anonymously.