Experimental Demonstration of an Advanced Package-Integrated Thin-Film Thermoelectric Cooler for on-Chip Cooling

The evolution of micro systems towards miniaturization and integration has driven continuous advances in on-chip thermal management technology to meet performance requirements such as high power and high frequency of chips. Thin-film thermoelectric coolers (TFTECs) are a solid-state cooling technology that can be integrated into electronic packages. While TFTECs have been recognized as a potentially optimal solution for electronic cooling, their fabrication process is complex and costly, making it challenging to achieve high performance and integrated applications. In this paper, we propose a method for fabricating TFTECs at the wafer-level using magnetron sputtering, photolithography, and wet etching techniques. The thickness of each leg is 10 μm. The device resistance and cooling temperature difference of the TFTEC are characterized to verify its functionality. Furthermore, the localized and real-time cooling performance of the TFTEC is evaluated by integrating it into a thermal test vehicle (TTV) using a flip-chip ball grid array (FC-BGA) package. At an input current of 50 mA, the TFTEC can cool a hotspot on the TTV chip by approximately 1.3 °C. This work can provide a promising on-chip thermal management solution for power devices and modules.