Thermal and Mechanical Properties of Electrically Insulating Thermal Interface Materials

In many electronic packaging applications, electrical insulation is required that can also provide high thermal conduction to appropriately couple a heat source to a heat sink. In these applications, it is the total thermal conductance, not the thermal conductivity, that must be maximized. This property is a result of both the bulk thermal conduction of the material as well as the nature of the interfaces between the electrical insulator, the electronic component, and the packaging. Here, an electrical insulator consisting of a filled polyimide is coated with a thin interfacial adhesive layer and the effect of this materials on the total thermal conductance is examined. This fundamental understanding of thermal conduction is developed by examining the influence of the bulk material properties and the coating layer thermal conduction between a heat source and a heat sink. The composite itself is then examined as a function of the conditions used to assemble the device in a standard thermal conductivity measurement system as well as real electronic device packaging.