Practical utilization of low melting alloy thermal interface materials

Abstract

The use of low melting alloy thermal interface materials results in exceptionally low thermal resistance between heat-generating electronic components and heat removal systems. Under certain conditions, these alloys can oxidize which may lead to degradation in thermal performance. In addition, if the alloy is used in the molten state, there is a possibility of electrical shorts resulting from escaping metal. Oxidation and electrical shorts are shown to be minimized through a variety of design parameters. These include the use of oversized metal alloy TIM's that form a seal around the interface area; soldering the low melting alloys directly to the heat removal component; use of a gasket to provide a barrier to prevent air from entering the interface area and to serve as a collection vehicle for excess molten alloy; and operating below the melting point of the alloy after a "burn-in" cycle. The use of low melting alloys, in conjunction with a series of design guidelines, provides a thermal solution with improved reliability and exceptionally low thermal resistance