Effect of hydrogen evolution on morphology and capillary performance of electrodeposited copper wicks

Effective thermal management is critical for ensuring the performance and reliability of high-power microelectronic devices. Vapor chambers (VCs) can facilitate heat dissipation through phase change and capillary circulation of the working fluid within the VC. Capillary wicks, the key to liquid circulation, are evaluated by the ratio of liquid permeability (K) to effective pore radius (Reff). In this study, porous copper wicks are electrodeposited with concurrently evolved hydrogen bubbles. The wick's morphology is modulated by varying sulfuric acid concentrations in the copper sulfate electrolyte. A geometric parameter, namely effective fluid transport volume (Veff) has been proposed to assess the permeability of working fluid in the porous copper wicks. The electrodeposited copper wicks demonstrate an optimal capillary performance (K/Reff) value of 1.31 mu m, surpassing the performance metrics of conventional powder-sintered copper wicks. This study presents a one-step electrodeposition method to modulate the morphology of porous copper wicks, thereby influencing their capillary performance through the strategic modification of the electrolyte.