Electrical properties of an isotropic conductive adhesive filled with silver coated polymer spheres

In the present study the electrical performance of newly developed epoxy resin based Isotropic Conductive Adhesives (ICAs) filled with silver coated mono sized polymer spheres have been investigated and compared with conventional solid silver particle/flake filled ICAs. The effects of particle size on the volume resistivity and percolation threshold of the new ICA have been studied. Two different diameters, i.e. 30μm and 4.8 μm, of silver coated mono sized spherical polymer particles have been used in this study. The results show that, for the same volume fraction, the volume resistivity of the adhesive with 4.8μm particles is lower than that with 30μm particles. The adhesive formulated with 4.8μm particles also exhibits a lower percolation threshold than that with 30μm particles. The resistivity of the adhesive containing 4.8μm particles was found to be of same order as that of currently commercially available ICAs, but with a significantly reduced silver content.