Preparation and optimization of capillary wick vapor chamber using copper paste based on capillary suspension

Absract To address the overheating issues in high-power integrated circuits, this article introduced a copper paste based on the capillary suspension which was printed on the vapor chamber. Research has shown that the addition of secondary fluid significantly changes the rheological properties of the paste. These rheological properties further influence the "boat-shaped" structure of the wick within the flow channel region. The article uses the capillary characteristic parameter ( ΔP cap × K ) to comprehensively consider capillary performance, with a maximum value of 1.349 × 10 –8 N, allowing the working fluid to overcome gravity and climb vertically 49 mm in just 5 s, demonstrating optimal comprehensive performance. The heat transfer test results of the vapor chamber show that the low starting power is 2 W and the maximum heat transfer power is 7 W. At maximum heat transfer power, the minimum temperature difference achieved is only 1.62°C, with a corresponding minimum thermal resistance of just 0.231°C/W, significantly outperforming pure copper plates of the same dimensions and thickness in heat transfer performance. This further demonstrates that the new copper electronic paste prepared based on capillary suspension possesses excellent application performance.