Epoxy Molding Compound for Electronic Packaging: Impact of Inorganic Filler Type and Geometry

Abstract Rapid technological advancements have increased the performance demands on electronic packaging materials, making epoxy molding compounds (EMCs) increasingly critical for electronic equipment. EMCs play a key role in protecting integrated circuits (ICs) and maintaining their reliability under severe conditions. Although extensive research has been conducted to enhance EMC performance through filler modification, a direct comparison of commonly used filler types remains limited. Thus, the present study focuses on comparing the effects of different fillers, which are aluminum nitride (AlN), aluminum oxide (Al2O3), barium sulfate (BaSO4), fused silica (fSiO2), and hexagonal-boron nitride (hBN), on the properties of bio-epoxy. Their impact on EMC-related properties such as viscosity, thermal properties, and electrical properties was studied. The results indicate that properties like thermal conductivity, coefficient of thermal expansion (CTE), and dielectric constant were affected by the intrinsic properties of the filler, whereas viscosity and Tg were mainly influenced by filler size. Furthermore, hBN was identified as the most promising filler for EMC applications due to its high thermal conductivity (0.80 W m−1 K−1), low dielectric constant (3.98 at 1 MHz), and CTE (40 ppm/° C), despite its high viscosity. We also discovered that BaSO4 exhibits poor compatibility with the epoxy matrix, consequently leading to poor filler–matrix interaction and poor EMC performance. This article provides a systematic comparison of filler type, geometry, and size on EMCs under similar content, offering insights into the filler’s impact on EMC performance.