Anisotropic thermal conductivity in electrically conductive adhesives with single- and bimodal filler-size distributions containing Ag flakes and micro-particles

Adhesives containing Ag flakes and spherical micro-particles were prepared. The variations in their electrical and thermal conductivities with matrix chemistry and curing temperature were investigated. Due to the alignment of Ag flakes along the in-plane direction, the adhesives containing only Ag flakes provided maximum thermal conductivity in this direction. Introduction of Ag spherical micro-particles effectively improved the thermal conductivity in the vertical direction for the bi- and single-modal adhesives. The adhesives containing only micro-particles are expected to be most effective from the viewpoint of the number of interfaces. However, the filler size distributions that provide maximum thermal conductivity in the vertical direction alter depending on the matrix chemistry and curing temperature due to variation in the interfacial thermal resistance between fillers.