Design and Fabrication of Multi-Layer Silicone Microchannel Cooler for High-Power Chip Array

With the development of high-power and highly-integrated microwave devices with chip array, there have been plenty of methods for high heat flux dissipation. However, the existing cooling architectures mainly focused on removal of single hot spot. For microwave devices with high-power chip array, there is a co-design of heat transfer enhancement and flow homogenization. In this study, we proposed a multi-layer silicone microchannel cooler for ${4\times 4}$ chip array cooling with heat flux of 500 $\mathbf{W}/\mathbf{cm}^{2}$ . Using a finite-element simulation, the flow distribution optimization was conducted and an H-type bifurcation structure was obtained. The optimized cooler has three layers: the liquid supply layer, the liquid return layer, and the microchannel layer. The size of whole microchannel cooler ${44 \text{mm} \times 44 \text{mm} \times 1.5}$ mm. The simulated results showed that a uniform velocity and pressure distribution was achieved in ${4\times 4}$ microchannels with an average velocity of 0.8 m/s and total pressure drop of 0.42 bar under flow rate of 36 L/h. The maximum chip temperature rise above the inlet temperature is 39°C with the temperature deviation less than ${1.0\ ^{\circ}{\mathrm{C}}}$ . We also fabricated a prototype of the optimized multi-layer silicone microchannel cooler using mature silicone etching and Si-Si bonding process. A thermal test system was built to evaluate the thermal performance of the cooler. The tested results showed that the maximum temperature rise was less than 40°C with the average temperature deviation less than ${\pm 5^{\circ}\mathrm{C}}$ . In summary, the proposed compact multi-layer silicone microchannel cooler achieved efficient and uniform cooling of high heat-flux chip array.