Surface-Treated\nThree-Dimensional Boron Nitride Epoxy\nComposite Dielectric for Smartphone-Printed Circuit Board Application

With the increasing need for efficient\nheat dissipation\nin high-end\nsmartphones, the development of dielectric materials for printed circuit\nboards (PCBs) with high thermal conductivity, a low dielectric constant,\nand strong adhesion characteristics is crucial. This study aims to\ndesign a composite dielectric addressing these often-conflicting properties\nand to examine its heat dissipation characteristics within an operating\nsmartphone. The composite is formulated using a resin mixture of diglycidyl\nthioetherdiphenyl, ortho-phenyl phenol novolac glycidyl ether, and\nbisphenol A diglycidyl ether, combined with surface-treated three-dimensional\nboron nitride fillers (<i>surf</i>-3D BN fillers). The <i>surf</i>-3D BN fillers, formed from aggregated two-dimensional\nboron nitride plates, address issues arising from the anisotropic\nthermal conductivity in individual components. Their surface treatment\nensures seamless integration with the native resin network enhancing\nboth thermal and mechanical performance. By carefully adjusting the\nresin composition and utilizing <i>surf</i>-3D BN fillers,\nthe composite achieves a high thermal conductivity of 5.4 W/m·K,\na low dielectric constant of 3.59, and a peel strength of 0.72 kgf/cm.\nFurthermore, replacing a fraction of the BN fillers with cost-effective\nSiO<sub>2</sub> fillers maintained the performance while reducing\nmaterial costs. The composite passed ion migration tests and exhibited\nsuperior heat dissipation in smartphone testbeds, making it a promising\ncandidate for next-generation PCB materials in advanced electronic\ndevices.