Sandwich-Structured Flexible Metal-Based Thermal Interface Material with Metal-Level Thermal Conductivity and Silicone-Level Elasticity Enabling Zero Contact Thermal Resistance

This paper reports a sandwich-structured flexible metal-based thermal interface material (FMTIM), which is composed of the thin Cu layers (top/bottom layers) and Cu microstructure array embedded in polydimethylsiloxane (PDMS) (compressible middle layer). The research results show that the FMTIM simultaneously achieves the metallevel vertical thermal conductivity ($k_{\perp}=194.66 \mathrm{W} \cdot \mathrm{m}^{-1} \cdot \mathrm{K}^{-} { }^{1}$) and silicone-level elastic recovery rate (36.6 %). This work breaks the traditional usage of TIMs by directly fabricating the FMTIM on the heat source and further processing the top Cu layer into an integrated Cu lid to achieve zero contact thermal resistance. Moreover, the FMTIM demonstrates excellent heat transfer performance in testing, even without additional pressure.