Investigating the synergistic effects of hybrid and bimodal filler networks on the out-of-plane thermal conductivity of polymer composites

초록

As 3D-integrated architectures such as high-bandwidth memory (HBM) increase in power density, managing vertical heat dissipation during burn-in testing (when temperatures can reach 280 degrees C) is critical. Traditional prepregs frequently lack sufficient thermal conductivity, causing thermal warpage or false device failures. In this study, we investigated monofiller, hybrid filler, and bimodal-morphology filler systems to increase the out-of-plane thermal conductivity (K perpendicular to) of styrene-ethylene-butylene-styrene (SEBS)-based polymer composites and prepregs at low filler loadings. While hybrid systems (h-BN/Al2O3) provide isotropic thermal bridges, they are hindered by high interfacial thermal resistance (Rint) at heterogeneous contacts. To address this issue, we developed a bimodal system using chemically identical h-BN fillers with different morphologies. This configuration facilitates an isotropic conduction network while reducing Rint through homogeneous filler-to-filler interfaces. At a total loading of 25 wt%, the aggregated bimodal prepreg achieved a K perpendicular to of 0.56 W/m & centerdot;K, which is an increase of 31% over the baselines of the monofiller. These results indicate that bimodal h-BN architectures comprise an effective method for developing high-performance, reliable substrates for next-generation semiconductor testing.

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