Fabrication and thermal analysis of a copper/diamond/copper thermal spreading device

This work describes the fabrication and thermal analysis of a newly developed Cu/diamond/Cu thermal spreading device. A Cu thin film was deposited onto a CVD diamond thin film sample by RF sputtering, and then the Cu thin film was electroplated to a thickness of 100 μm. The thermal spreading device was made by removing the underside silicon of the substrate and sputtering Cu films on the back of the diamond again. The adhesion of Cu onto the diamond was analyzed by performing scratch and pull-off tests. Thermal conductivity of the Cu/diamond/Cu device was then measured and compared with a pure Cu heat spreader, and the diamond device revealed a thermal conductivity over 6.5 W/cm K. A thermal cycle test of Cu on diamond revealed adhesion that suffices to resist thermal stress at 200 °C for a long time. We have demonstrated an application of this device to power LEDs as a heat spreader with excellent thermal conductivity.