Electrodeposited Copper Micropillar Surfaces with Pulse Reverse Voltammetry for Enhanced Heat Dissipation

Microstructured metal coatings are promising for many commercial applications due to their robustness, high thermal and electrical conductivities, and interesting functionalities. In particular, copper electrodeposition has been widely studied due to its low cost and scalability while maintaining excellent material quality. Here, we use pulse electrodeposition to simultaneously monitor and generate copper microstructures on copper and aluminum surfaces. By rapidly applying forward and reverse potentials, we identify a key metric—the ratio of deposition to etching—that has a characteristic temporal profile for four different growth regimes: thin films, pyramids, micropillars, and dendrites. We explore the parameter space by varying the forward voltage between 100 and 500 mV and added chloride between 100 and 1000 ppm to transition the microstructure between these four growth regimes, allowing us to obtain the desired surface structure. With this capability, we deposit micropillar arrays on large-area copper and aluminum heat sink surfaces, yielding performance enhancements of 10 and 4%, respectively, showing that such coatings are promising for thermal management applications.