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Module for Improved Heat Dissipation

IP.com Disclosure Number: IPCOM000037733D
Original Publication Date: 1989-Jun-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Mulligan, GP: AUTHOR [+2]

Abstract

New generation chips operate at power levels exceeding 20 watts and require advanced thermal packaging to dissipate this heat. Cooling these chips with current thermal grease or RFC designs is not effective. The arrangement of a module as described herein has the high thermal performance dictated by the new generation chips.

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Module for Improved Heat Dissipation

New generation chips operate at power levels exceeding 20 watts and require advanced thermal packaging to dissipate this heat. Cooling these chips with current thermal grease or RFC designs is not effective. The arrangement of a module as described herein has the high thermal performance dictated by the new generation chips.

Fig. 1 shows the module arrangement. It is based on a standard module with two modifications. One, the metallized land pattern on the standard ceramic substrate is replaced with a corresponding single-sided decal. The decal, after a chip is attached, is soldered to the tops of 20 mil pins and employs laser etched solder vias in the pin-pad areas.

The second modification is concerned with the thermal arrangement. An aluminum nitride, thermal interposer is bonded to the aluminum cap using a thin layer of flexible adhesive, such as, for example, Dow Corning Sylgard silicone adhesive. A thin (1 mil or less), void-free adhesive joint is obtained by a vacuum curing under compressive loading. The size of the interposer is larger than the chip to enhance thermal performance. The interposer and the chip are connected, during the capping operation, with a thin layer of thermally conductive epoxy. Any tolerance variations in the assembly can be accommodated by the flexibility of the decal. Thermal strains produced during operation of the chip are moderated by compliance of the adhesive layer and by the decal.

Disclos...