Experimental and numerical study of CVD diamond microchannel cooling for high heat flux heterogeneous material-integrated dies

Abstract

With the continuous advancement of integrated circuits toward higher integration and power density, thermal management of chips faces significant challenges. This study proposes a heterogeneous material -integrated cooling scheme based on chemical vapor deposition diamond microchannels (CVD-DMCs) and systematically investigates its heat transfer performance under ultra-high heat flux conditions through combined simulation and experimental methods. Initially, a comparative simulation analysis was conducted for different rib structures with rectangular, circular and rhombic cross-sections. The rhombic rib was identified as the optimal configuration, with rib depth (D) and width (W) as key geometric parameters. A non-uniform multi-heat-source test die incorporating dual large-area and multi-point small-area Pt films was fabricated and bonded, via AuSn eutectic bonding, to a femtosecond laser-machined CVD-DMC structure mounted on an AlN substrate, forming a complete test model. Experimental results under extreme conditions of 144 mL/min flow rate, heat fluxes of 1100 W/cm² (dual large-area) and 11000 W/cm² (multi-point small-area) demonstrated that the rhombic rib structure with a D of 0.5 mm, W of 0.15 mm achieved the best cooling performance among the structures investigated in this study. lowering die temperature to 108 °C with a pressure drop (ΔP) of 11.22 kPa. Further analysis indicated that optimizing rib width is more effective than rib depth in enhancing heat transfer while minimizing flow resistance. Moreover, the feasibility and accuracy of integrating multi-point small-area for localized heating and temperature measurement at the chip level were verified. This work reveals the critical influence of CVD-DMCs rib structures on thermal performance and proposes an efficient integrated cooling design for high heat flux electronic devices.