Performance analysis of Gallium-based liquid metal as thermal interface material for chip heat dissipation

Abstract

Effective heat dissipation is crucial for reducing chip operating temperatures and improving energy efficiency in data centers. As chip heat generation continues to rise dramatically, interfacial thermal resistance has emerged as a significant bottleneck for heat dissipation. Therefore, identifying thermal interface materials (TIMs) with high thermal conductivity and low thermal contact resistance is essential. In this study, we propose using a liquid metal alloy composed of 75 % gallium and 25 % indium as a TIM, which boasts a high thermal conductivity of 26.6 W/m·K and a low thermal resistance of 2.8 mm²·K/W. A theoretical mathematical model was developed to characterize interfacial heat transfer. Experiments were conducted to compare the heat dissipation performance of liquid metal with that of thermal grease used as TIMs. Furthermore, numerical simulations were performed to analyze the effects of heating power, TIM thickness, and thermal interface area on the chip heat dissipation performance. The experimental results show that liquid metal significantly outperforms thermal grease as a TIM, with the heat source temperature being 9.8 °C lower for liquid metal at a heating power of 90 W. Numerical simulations reveal a linear increase in heat source temperature with rising heating power. Moreover, both reducing the TIM thickness and increasing the thermal interface area improve heat dissipation performance. Specifically, when the TIM thickness was reduced from 2 mm to 0.2 mm and the thermal interface area was increased from 6.25 cm² to 16 cm², the heat source temperature was decreased by 8 % and 35.9 %, respectively. This study highlights the potential of liquid metal as a TIM for the thermal management of high-power-density chips, such as CPUs, GPUs, and AI accelerators, while providing valuable insights for enhancing the design of chip cooling systems.