Browse Prior Art Database

Cooling Device for Multilayer Ceramic Modules

IP.com Disclosure Number: IPCOM000089260D
Original Publication Date: 1977-Oct-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 86K

Publishing Venue

IBM

Related People

Clark, BT: AUTHOR [+2]

Abstract

The cooling device interface with the chip should exhibit minimum thermal resistance and its pressure on the chip should not exceed the creep resistance of the C-4 junctions. Similarly, its interface with the module protective cap, or cold plate, should be resilient to allow for thermal expansion differential and manufacturing variations. Yet this interface should have low thermal resistance and allow for cap-to-substrate hermeticity. The device should be made of material physically and chemically compatible with the substrate, the chip, the C-4 junctions and all other components of the module. The cooling device disclosed herein includes two elements, a metal bellows and a heat pipe.

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Cooling Device for Multilayer Ceramic Modules

The cooling device interface with the chip should exhibit minimum thermal resistance and its pressure on the chip should not exceed the creep resistance of the C-4 junctions. Similarly, its interface with the module protective cap, or cold plate, should be resilient to allow for thermal expansion differential and manufacturing variations. Yet this interface should have low thermal resistance and allow for cap-to-substrate hermeticity. The device should be made of material physically and chemically compatible with the substrate, the chip, the C- 4 junctions and all other components of the module. The cooling device disclosed herein includes two elements, a metal bellows and a heat pipe.

As illustrated in Figs. 1 and 2, the device is essentially a thin metal cylindrical structure 1, forming a pipe, sealed at both ends and containing a wick and cooling fluid. Its upper portion, which is the condensing end, is cylindrical, and remains attached to a rigid structure (mounting plate) spaced a fixed distance from the substrate. Its lower portion is formed of convolutions calculated to allow a high degree of freedom along the axis of symmetry of the pipe and within the plane established by the upper surface of the chip. The lower end of the pipe interfaces with the chip via a soft metal 2.

The device operates like a conventional heat pipe. That is, heat is extracted from the working fluid by evaporation at the chip end (hot en...