Evaluation of Thermocompressed Nanoporous Copper Deposit to Replace Soldering for Power Electronic Metal Foam Heat Sinks

Metal foams appear as innovative solutions for cooling high-density power electronic systems. In these assemblies, the foam is currently soldered on a copper substrate. However, the temperature of solders is limited and their aging under high thermomechanical constraints is a clear weakness of this solution. A novel way to attach metal foams to copper substrates is presented in this article, the thermocompression of a nanoporous copper deposit. The obtained attachments show good densification of the deposit, and the conducted shear tests show an increase in the contact mechanical strength with increasing thermocompression time. In addition, using a dynamic methodology, the thermal contact resistance of such joints is evaluated which shows results similar to those obtained on soldered joints.