Thermal conductivity and dielectric properties of immiscible LDPE/epoxy blend filled with hybrid filler consisting of HGM and nitride particle

The packaging and substrate materials with high thermal conductivity, low Dk and Df values are required to guarantee heat dissipation and signal propagation of integrated circuits. In this paper, the mixtures of HGM (S60HS or S38HS) and nitride particle (AlN or BN) were used as a hybrid filler to prepare composites with a matrix of immiscible LDPE/epoxy blends. The effects of the volume ratio of LDPE to epoxy and the volume fraction and type of hybrid filler on the thermal and dielectric properties of the composites were investigated. By adjusting the volume ratio of LDPE to epoxy and the volume fraction and type of hybrid filler, an optimum combination of thermal conductivity and dielectric properties is obtained for the composites. SEM observations indicate that the hybrid filler particles are mostly distributed into the epoxy phase in the composites, and thus thermally conductive networks of filler particles can be easily constructed at a suitable volume ratio of LDPE to epoxy and the BN particles with a platelet morphology are best suited for this purpose. The Agari model can be applied to describe the thermal conductivity of the composites and the Maxwell-Garnett and J-S models can roughly predict the Dk of the composites in the case when the nitride powder used is AlN, but they are not applicable in the case when nitride powder used is BN.