Thermal management of integrated circuits (ICs) has become a limiting factor for transistor frequency, which has stalled around a few gigahertz over the past decade. The large thermal loads stem from extremely densely packed, nanometer- sized features of modern ICs, which provide minimal surface area for dissipation of the generated heat. This limitation has motivated the development of novel thermal interface materials (TIMs) that can more efficiently conduct heat away from such hotspots.
In a project sponsored by Semiconductor Research Corporation with Prof.Robert Wang from ASU, we developed highly conductive pad-type TIMs that are composed of novel multiphase fillers dispersed in elastomer matrix (see Ralphs et al. ACS App. Mater. Interf., 2018). We also developed highly conductive (60 W/mK) LM pastes with tungsten particle additives and liquid metal foams (see Kong et al. Adv. Mater, 2019, Soft Matter 2020, and Adv. Mater. Inter.2021). In cases where TIMs have to be electrically insulating, we propose to engineering of the nanowire-type filler with liquid metal coated tips (see underlying theory introduced in Rykaczewski and Wang, APL, 2018). In addition to individual filler particle engineering, we are exploring thermal conductivity enhancement through, for example, magnetic field alignment of the particles (see Ralphs et al., Journal of Heat Transfer, 2018 & Ralphs et al. Adv. Mater. Inter. 2019). With new funding from NSF with Prof. Michael Dickey’s group from NCSU we are further exploring the new concepts of liquid metal foams and pastes.
