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Browse Prior Art Database

Method of Reducting Thermal Stress on Ceramic Substrate of Thermal Conduction Module

IP.com Disclosure Number: IPCOM000105298D
Original Publication Date: 1993-Jul-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Kimura, S: AUTHOR [+2]

Abstract

Disclosed is a method to reduce the thermal stress on a ceramic substrate caused by a thermal co-efficient mis-match between the ceramic substrate and a metal packaging hardware. The disclosed method is to apply a thin grease layer on surfaces between the substrate and the metal packaging hardware.

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Method of Reducting Thermal Stress on Ceramic Substrate of Thermal Conduction Module

      Disclosed is a method to reduce the thermal stress on a ceramic
substrate caused by a thermal co-efficient mis-match between the
ceramic substrate and a metal packaging hardware.  The disclosed
method is to apply a thin grease layer on surfaces between the
substrate and the metal packaging hardware.

      The figure shows a cross section of TCM (Thermal Conduction
Module).  TCM includes a substrate and a packaging hardware.  The
packaging hardware includes a hat, a baseplate, a metal-ring and a
cushion.  A shearing force is exerted on the substrate through the
contact surface between the baseplate and the substrate during
heating process, because the thermal expansion co-efficient of metal
(baseplate, hat) is larger than that of ceramic (substrate).  This
shearing force causes the tensile stress in the substrate (thermal
stress).

      The shearing force can be reduced by inducing a slip between
the contact surfaces.  The slip condition is determined with maximum
static friction co-efficient and metal-ring spring-back force.  A
less-friction co-efficient and/or a weaker spring-back force is
necessary for lower shearing force.  The metal-ring spring-back
force, however, can't be reduced easily because of other design
restriction.  So, reducing the friction co-efficient is the key point
in order to reduce the maximum shearing force and consequently the
thermal str...