Epoxy/h-BN composites for thermally conductive underfill material

In order to enhance thermal conductivity of underfill materials, hexagonal boron nitride (h-BN) was employed as a thermally conductive filler. The relationship between the filler morphology and its effects on the thermal conductivity is focused in this study. Two different h-BN fillers with different morphologies were applied to generate an efficient thermal transport path through the filler and epoxy resin interfaces. The microstructure, dynamic mechanical properties and thermal conductivity for the h-BN filled underfills were studied and characterized. The h-BN greatly increased the thermal conductivity of the underfill and their moduli were well controlled by an addition of a low filler level which can reduce the thermal stress in flip-chip packaging application.