Influence of metallization and size on the conductive properties of metal-coated polymer particles in anisotropic conductive adhesive

摘要

Metal-coated polymer particles are a key component in anisotropic conductive adhesives for a variety of interconnect applications. The electrical resistance of the interconnect is strongly linked to the mechanical deformation of the particles in the adhesive. In order to investigate the influence of metallization system, coating thickness and particle size, electromechanical nanoindentation was employed to measure the single particle resistance-deformation properties of 3-10 μm particles with gold, nickel-gold and silver coatings with thicknesses from 20-120 nm. Furthermore, a bonding test was performed to compare particle performance in air and adhesive. Despite yielding the lowest resistance the electromechanical nanoindentation test, the silver coatings showed the poorest performance in the bonding test. This demonstrates that factors other than the particle resistance, such as the contact resistance and penetration of the adhesive layer, may influence the final interconnect performance.