Heat Sink Performance of Electrodeposited Copper-Diamond Composites

Abstract

The rapid advancement of modern electronics has intensified thermal management challenges, driving the need for heat sink materials with high thermal conductivity and efficient heat removal. Electrodeposited copper-diamond (Cu-D) composites show strong potential for next-generation electronic applications, offering thermal conductivities exceeding those of conventional metals while remaining more economical than composites produced through high-temperature-high-pressure methods. Despite this promise, most studies emphasize intrinsic material properties rather than evaluating practical cooling performance. This thesis investigates the heat sink behavior of electrodeposited Cu-D composites under realistic operating conditions using LED junction-to-ambient thermal resistance. Cu-D samples containing uncoated and TiC-coated diamond particles, arranged in single-layer and multi-layer architectures, were fabricated and assessed. Uncoated composites exhibited poorer heat sink performance than pure copper due to small, equiaxed copper grains near the Cu-D interface, which limited thermal boundary conductance despite being free of interfacial voids. In contrast, TiC-coated diamond particles significantly lowered steady-state LED temperatures, demonstrating the importance of interfacial engineering in improving phonon transport across metal-diamond interfaces. The influence of thermal interface materials (TIMs) was also examined. Incorporating 10-30 wt.% diamond particles into the commercial thermal paste further reduced LED temperatures, even though the thicker bond-line would typically increase thermal resistance. This shows that TIM formulation plays an additional role in determining overall heat sink effectiveness. Overall, this work advances electrodeposited Cu-D composites toward practical heat sink applications and shows that interfacial coatings, copper microstructure, and TIM design collectively influence thermal performance.