Capillary behavior of V-shape microgroove for vapor chamber fabricated by DOE-assisted femtosecond laser processing

Thermal performance of passive heat spreader vapor chambers is mainly determined by the performance of evaporation, which is highly dependent on the permeability of wicks. Most existing studies on wick permeability focus on the wick itself, while the effects of fabrication and assembly processes are often overlooked. In this paper, accurate V-shape microgrooves were fabricated by femtosecond laser efficiently with a diffractive optic element, and their capillary behavior was experimentally characterized using de-ionized water. A theoretical model was developed to describe liquid transport in such geometries, and finite-element simulations further validated the theoretical predictions. In addition, the degradation of permeability during heat treatment and prolonged air exposure was systematically investigated, and an effective recovery method was proposed. This finding provides a framework for optimizing groove fabrication and preserving wick performance during vapor chamber manufacturing.