Newer electronic devices generate more heat because increasing their performance means increasing their power density. To avoid temperature damage this heat must be removed. This dictates the need for improved thermally conductive materials. Adhesives are widely used to assemble electronic equipment and are often part of the critical heat flow path out of the equipment. Polymeric adhesives. particularly epoxies, are the most commonly used adhesives because of their low processing temperatures and ease of use. They unfortunately have poor thermal conductivities and are unsuitable for newer generation high power electronic devices. A Phase I program met its goal by developing an epoxy adhesive film that demonstrated a thermal resistance lower than solder with a raw material cost comparable to current silver filled epoxy adhesives. Its thermal conductivity is 20 to 50 times higher than other polymeric adhesives. This Phase II effort will concentrate on developing a prototype process that is capable of producing the adhesive in a continuous, reliable manner. The emphasis will be on an epoxy adhesive to replace solder as a die attach bonding material for high power integrated circuit packages. Its goals are processing at 120°C, thermal resistance equal to soft solder, and an overall cost of use lower than solder. Evaluation will be conducted with the goal of implementation on a production electronic packaging line. Versions of the die attach adhesive will be explored that cure in under a minute, that have a thermal conductivity approaching pure silver, and that have a lower cost. A thick version of the adhesive will be evaluated as a replacement for copper heat slugs. An elastomeric sheet version of the adhesive will be developed and evaluated as a heat fin thermal attachment for high power devices. A version of the adhesive will be developed for z-axis electrical conductivity.
Keywords: Adhesive Thermal Conductivity
