Effect of the thickness of a thermal interface material (solder) on heat transfer between copper surfaces

Abstract

Solder applied in the molten state was used as a thermal interface material between copper surfaces. The effect of the solder thickness on the heat transfer between the copper surfaces was studied by measuring the thermal contact conductance using the laser flash method. Increasing the thickness of solder from 10 to 30 mm was found to increase the heat transfer time (temperature rise time) by 25%. The effect is akin to replacing solder with an interface material that is 80% lower in thermal conductivity. It is also akin to decreasing the thermal contact conductance of the solder-copper interface by 70%. Thus, minimization of the solder thickness is recommended in practice.