Sandwich‐structured In–Ga alloy phase change thermal pad with low thermal resistance and leakage prevention
Pingjun Luo, Xu Huang, Haoran Yang, Sheng Chu
Abstract
Abstract With the rapid increase in chip integration and power density, there is a growing need to develop advanced thermal interface materials for effective thermal management. Liquid metals with high thermal conductivity, excellent gap‐filling capability and non‐toxicity have received much attention. However, low‐melting‐point metals, such as galinstan and indium‐bismuth‐tin (EInBiSn) eutectic alloys, are prone to leaking, which limits their applications. In this study, In–Ga alloy composite thermal pads with a sandwich structure and a graphite film as an intermediate layer were prepared. The In–Ga alloy composition was adjusted so that these pads underwent partial phase change in the operating temperature range of the laptop CPU (50–100 °C). This results in low thermal resistance and leakage prevention. The thermal resistance of the InGa5, InGa15 and InGa25 alloy thermal pads decreases to 7.3, 4.1 and 2.66 K·mm 2 ·W −1 , respectively, at a temperature and pressure of 100 °C and 50 psi. In a test measuring the actual cooling effect of the fabricated material on a CPU, the InGa15 alloy thermal pad maintained the average CPU temperature at 90.1 °C, significantly better than the EInBiSn thermal pad with an average CPU temperature of 94.1 °C, and comparable to Galinstan, which had an average CPU temperature of 89.3 °C. Due to their good heat dissipation and leak‐proof properties, In–Ga alloy composite thermal pads are expected to become a new generation of thermal interface materials.