Enhanced capillary performance of an aluminum-based vapor chamber by laser layered processing of microgroove wick structures

Vapor chambers (VCs) are highly effective for electronic cooling, with the wick structure being the critical component. To fabricate high-efficiency microgroove wick structures, this study proposes a laser processing technique to split an inverted V-shaped microgroove into a series of rectangular regions with equal height and gradual width. Each rectangular region represents a processing level, and the layers are stacked to machine a microgroove wick structure with a large aspect ratio and a V-shaped cross-section at a specific angle on an aluminum alloy plate. The capillary performance of three microgroove wick structures with different depths corresponding to three angles was investigated. The results showed that the capillary height could reach 100 mm (total sample height) within 60 s for all the samples. When the microgroove angle is 30° or 45° and the depth is 300 μm, the capillary height can reach the top of the sample in 10 s. In the initial stage, the average wicking velocity of the two cases is the largest, approximately 21.8 mm/s, and the average wicking velocity is increased by approximately 115.84% relative to that of the depth is 100 μm. Calculations of the comprehensive capillary performance parameter K/R eff reveal that increasing microgroove depth from 100 μm to 300 μm yields significant enhancements: approximately 300% for the 30° configuration and 325% for the 45° configuration. This study provides a new concept for machining a simple and reliable aluminum-based VC wick.