Optimization and fabrication of an in-plane radial thin-film thermoelectric cooler for chip hotspot cooling

With the advancement of 3D electronic packaging integration and power density, chip hotspot has increasingly become a technical bottleneck restricting its development. The thin-film thermoelectric cooler (TFTEC) is a highly integrated and lightweight solid-state cooling technology, which is considered to be the potential optimal solution for on-chip thermal management of power electronics. In this paper, an in-plane TFTEC with the radial planar structure for chip hotspot cooling is proposed and optimized by using the finite element method. The influences of substrate material, substrate thickness, and thermoelectric element thickness on the cooling performance of the device are discussed. The results show that when a 25 μm polyimide flexible substrate is used, the maximum cooling temperature difference compared to the ambient temperature can reach 17.49 °C, and the minimum cooling temperature can reach 7.51 °C. The cooling performance of the in-plane radial TFTEC also can be improved by appropriately increasing the thickness of the thermoelectric element. Furthermore, the in-plane radial TFTEC is fabricated by physical vapor deposition and lifting-off process, and its cooling performance is preliminarily characterized. This work can provide a feasible technical approach for on-chip hotspot cooling solution.