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Browse Prior Art Database

Heatsink Stand for Fully Encapsulated Substrate

IP.com Disclosure Number: IPCOM000106845D
Original Publication Date: 1993-Dec-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Caletka, DV: AUTHOR

Abstract

Increased thermal performance of logic chips can be realized with the use of a direct attach heatsink. Logic chip/interconnection (C4) reliability can be improved through full encapsulation of chip and substrate. Poor thermal conductivity of typical encapsulation materials tends to make direct chip cooling difficult. Both objectives may be attained with the use of a heatsink stand attached to the chip back surface.

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Heatsink Stand for Fully Encapsulated Substrate

      Increased thermal performance of logic chips can be realized
with the use of a direct attach heatsink.  Logic chip/interconnection
(C4) reliability can be improved through full encapsulation of chip
and substrate.  Poor thermal conductivity of typical encapsulation
materials tends to make direct chip cooling difficult.  Both
objectives may be attained with the use of a heatsink stand attached
to the chip back surface.

      In Fig. 1, a heatsink stand (1) is attached to the chip (2)
back surface, either with a thermally conductive adhesive or the
substrate encapsulant (3) to be used for reliability enhancement.
The chip (2), previously attached to the substrate (4), is
encapsulated (5) prior to heatsink stand attachment and substrate
encapsulation.  If a UV cured substrate encapsulant is to be used, a
perforated heatsink stand (6), as in Fig. 2, may be used to allow
curing of encapsulant under the stand.  Hole size (7) and mounting
post (8) diameter can be optimized for thermal performance.  A
heatsink is subsequently bonded to the heatsink stand with a
thermally conductive adhesive.