High-Performance Electrodeposited Copper Wicks for Heat-Spreading Vapor Chambers

With the increasing heat flux in electronic packages or power electronic devices in the last decade, vapor chambers have been considered a promising solution to this problem due to their excellent thermal performance. A capillary wick structure plays an important role in producing the capillary pressure that drives two-phase circulation in phase-change heat transfer devices such as heat pipes and vapor chambers. In this study, the porous Cu wick structures were fabricated using a new electrodeposition process and examined for their capillary performance. This Cu wick exhibits large channels generated by hydrogen bubbles and small pores in the dendritic Cu deposits produced by high-current electrodeposition. Adjusting the morphology of dendritic copper deposits by using different electrodeposition current densities and copper sulfate concentrations in the electrolyte can effectively enhance the capillary wick performance. The Cu wick is then thermally treated at 700 °C in ambient N₂for 90 min to improve its structural integrity. The Cu wick shows a superior capillary performance<i> K</i>/<i>R_eff</i> of 1.5 ± 0.06 mm and excellent structural stability. Such a high capillary performance can enhance the mass transport rate and effective transport distance of the working liquid in vapor chambers for high-density and long-range heat dissipation applications. Test results demonstrated that a vapor chamber integrated with an electrodeposited Cu wick has excellent heat-spreading characteristics, with an effective thermal conductivity of up to 13500 W/m×K.