Fecha de publicación: -- Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE A hybrid-filler strategy combining platelet boron nitride and spherical alumina is developed to address thermal-management challenges. The complementary fillers enable a filler loading of 37.6 vol% while maintaining moderate viscosity under the tested conditions. The composite achieves a thermal conductivity of 2.28 W m−1 K−1 and exhibits promising electrical insulation and thermomechanical properties, supporting its potential for fine-pitch underfill applications.

ABSTRACT
Advanced electronic packaging requires underfill materials with both high thermal conductivity and excellent processability, a demand that is further intensified by rising power densities and finer pitches. In this study, epoxy (EP) composites incorporating a hybrid filler system consisting of 1 μm hexagonal boron nitride (BN) platelets and 300 nm spherical alumina (Al2O3) are systematically investigated to address this challenge. The incorporation of spherical Al2O3 enables higher total filler loadings while maintaining processable viscosity. The optimized 65BN-80Al2O3/EP composite achieves a thermal conductivity of 2.28 W m−1 K−1 at a total filler loading of 37.6 vol%, which is approximately 9 times that of neat epoxy and 30.3% higher than that of the 65BN/EP composite. The measured electrical and thermomechanical properties further support the potential of these composites as underfill candidates. Overall, this hybrid filler strategy based on small-sized, multi-morphology ceramic fillers offers a promising approach to addressing thermal management challenges in fine-pitch electronic packaging.