Properties and reliability of molybdenum-copper-composites for thermal management applications

Multilayered composites made of molybdenum and copper combine a low coefficient of thermal expansion with a high thermal conductivity. By varying the layer structure, both properties can be tailored to the application requirements. Therefore, these composites are interesting candidates for the thermal management of electronics in general and especially for thermal management of GaN based devices. In this work reliability tests were performed on a three layered structure (Cu-Mo-Cu) with 63 wt% copper according to EN 60068-2-14. The results show that the interface is not degrading by thermal cycling between -40 °C and +125 °C after 2000 cycles. Moreover, no change in thermal conductivity or flatness of the samples was observed. The molybdenum-copper-interface was found to be stable up to the melting point of copper.