Poly(ionic liquid)s:\nA Promising Matrix for Thermal\nInterface Materials

The swift progression of high-density chiplet packaging,\npropelled\nby the artificial intelligence revolution, has precipitated a critical\nneed for high-performance chip-scale thermal interface materials (TIMs).\nThe elevated thermal resistance, limited interfacial adhesion, and\nmechanical flexibility intrinsic to silicone systems present a substantial\nchallenge in meeting reliability standards amidst chip warpage. This\nparticular matter underscores a significant performance bottleneck\nwithin existing high-end TIMs. In this study, we present poly(ionic\nliquid)s (PILs) as an innovative matrix for TIMs. Our findings highlight\nthe unique properties of PILs, showcasing a low elastic modulus (60\nkPa), exceptional flexibility and stretchability (>3800%), high\nadhesion\nto diverse substrates (up to 4.10 MPa), favorable filler compatibility,\nremarkable thermal stability, and prompt self-healing capabilities\ncoupled with recyclability. The collective findings suggest that the\nPIL serves as an ideal matrix for heat transfer. As a proof of concept,\nPIL blended with liquid metal was straightforwardly combined to produce\na TIM, exhibiting exceptional performance within practical encapsulated\nstructures. The PIL-based TIM demonstrates substantial elongation\nat break (>350%), coupled with sustained high adhesion strength\n(up\nto 1.70 MPa), and exhibits favorable thermal conductivity in package\ntesting. This study presents an innovative TIM matrix with the potential\nto enhance existing TIM systems, delivering significant performance\nbenefits compared to silicones. Besides elucidating their multifaceted\ncharacteristics, this study forecasts an expanded range of applications\nfor PILs, along with laying the groundwork for advancing next-generation\nTIMs.