Browse Prior Art Database

Perforated Polydimethylsiloxane Rubber as Thermal Paste Retainer

IP.com Disclosure Number: IPCOM000113863D
Original Publication Date: 1994-Oct-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Conte, J: AUTHOR [+5]

Abstract

With the increasing power consumption of integrated circuits cooling is becoming ever more important. One way of cooling chips is achieved by placing a thermal paste between the chip and a cooling cap. Thermal pastes consist of thermally conducting solids and oil. Gap movement as it occurs during powering up and down of the chip can lead to leaking of the oil and preferential coating of the chip and cooling cap surfaces. These coatings allow the paste to slip out of the gap leading to increased thermal resistance and decreased lifetime of the chip.

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Perforated Polydimethylsiloxane Rubber as Thermal Paste Retainer

      With the increasing power consumption of integrated circuits
cooling is becoming ever more important.  One way of cooling chips is
achieved by placing a thermal paste between the chip and a cooling
cap.  Thermal pastes consist of thermally conducting solids and oil.
Gap movement as it occurs during powering up and down of the chip can
lead to leaking of the oil and preferential coating of the chip and
cooling cap surfaces.  These coatings allow the paste to slip out of
the gap leading to increased thermal resistance and decreased
lifetime of the chip.

      The problem can be alleviated by coating one of the gap
surfaces (preferably the cooling cap surface) with a design intended
to produce a mechanical barrier to slipping.  This barrier might be a
1 micrometer thick perforated coating, a grid or an outline of the
chip
all made from silicone rubber.  Additionally to providing a
mechanical
barrier the silicone rubber can absorb the excess silicone oil on its
surface producing a smooth transition from the paste to the cooling
cap.  The impact on heat conduction produced by the silicone rubber
film
is minimized by the design that leaves plenty of direct contact
between
cooling cap and thermal paste.

      The silicone rubber designs can be applied using a printing
process utilizing the uncured silicone rubber/crosslinker mixture.
Printing is possible because the rubber can be diluted bef...