Enhanced capillary performance of hierarchical dendritic copper surface for ultrathin heat-spreading devices

• Published in: Physics of fluids (1994) Vol. 35; no. 7
• Main Authors: Chiang, Chao-Yang, Yu, Jui-Cheng, Liu, En-Chia, Chiu, Shaw-Woei, Liao, Chien-Neng
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 01.07.2023
• Subjects: Copper; Dendritic structure; Dissipation; Electrodeposition; Electronic systems; Fluid dynamics; Physics; Pore size; Portable equipment; Sintering; Sintering (powder metallurgy); Structural integrity; Wicks
• ISSN: 1070-6631; 1089-7666
• DOI: 10.1063/5.0159733

High-performance electronic systems require efficient heat dissipation devices. Vapor chambers (VCs) are practical thermal solutions for lightweight portable electronics that have limited heat dissipation space. A functional VC requires an interior wick to sustain the capillary circulation of the condensed fluid back to the heated region. The capillary wick performance can be indexed by the ratio of liquid permeability to the effective pore size of the wick structure. This study describes the capillary behavior of a thin hierarchical dendritic copper film (<100 μm thick) prepared by electrodeposition and thermal sintering. The effects of the electrodeposition current density, deposition time, and sintering temperature on the capillary performance of the dendritic copper films were investigated. The relationship between the wicking capability and dendritic morphology, tailored by the electrodeposition process, was explored. A post-deposition sintering treatment was found to be beneficial for improving the structural integrity, adhesion, and capillary performance of dendritic copper wicks. A very high capillary performance (0.81 μm) was realized on a 30-μm-thick dendritic copper wick that matches the need for ultrathin VCs used in highly compact electronic systems.