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TCM Encapsulation Springs That Minimize the Effects of Contamination Particles on Thermal Contact Resistance

IP.com Disclosure Number: IPCOM000036011D
Original Publication Date: 1989-Aug-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Edwards, DL: AUTHOR [+2]

Abstract

Contamination particles at the chip-to-cooling-hardware interface are the major contributor to the uncertainty of the interface's range of thermal resistance. Particles which are large enough to disrupt the interface can, with this invention, be crushed and/or imbedded into the cooling hardware because of large forces present during hardware encapsulation. This will result in a consistently smaller mean spacing at the chip-to-cooling-hardware interface, and therefore a smaller range of contact resistances. A Shape Memory Alloy (SMA) spring provides a means by which the large force at the chip-to-cooling-insert interface can occur during cooling-hardware encapsulation and then subsequently reduced to a force adequate to maintain thermal contact.

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TCM Encapsulation Springs That Minimize the Effects of Contamination Particles on Thermal Contact Resistance

Contamination particles at the chip-to-cooling-hardware interface are the major contributor to the uncertainty of the interface's range of thermal resistance. Particles which are large enough to disrupt the interface can, with this invention, be crushed and/or imbedded into the cooling hardware because of large forces present during hardware encapsulation. This will result in a consistently smaller mean spacing at the chip-to-cooling-hardware interface, and therefore a smaller range of contact resistances. A Shape Memory Alloy (SMA) spring provides a means by which the large force at the chip-to-cooling-insert interface can occur during cooling-hardware encapsulation and then subsequently reduced to a force adequate to maintain thermal contact.

An example of a SMA/conventional coil spring combination within a piston TCM is as follows. During the encapsulation process, a SMA spring and a conventional spring exert parallel forces on the back face of a piston contacting a chip, whereby the sum of their forces is large enough to crush and/or imbed contamination. Once the hardware is assembled, the entire module is heated to an elevated temperature. Upon heating, the SMA spring shrinks to a length smaller than the space available, and hence its contribution to the high force is eliminated. The remaining force exerted on the chip is from the conventional spring...