Rate-dependent mechanical properties of cured conductive adhesives and drop impact behavior of adhesive bonding points in electronic interconnection

Given the boom of portable electronic products and the increasing risk of drop impact load in electronic interconnection points, the rate-dependent mechanical properties of cured conductive adhesives and the drop impact behaviors of packaging structures interconnected with conductive adhesives with 50 and 60 wt% silver filler contents were investigated in this study. The quasi-static and dynamic compression stress–strain curves and deformation failure modes of cured conductive adhesives were obtained using an Instron universal material testing machine and a split Hopkinson pressure bar apparatus. The mechanical properties dependent on strain rate were characterized by Cowper–Symonds model. Numerical simulation of the drop impact behavior of the packaging structures was carried out by the general finite element software, LS-DYNA. Then, the von Mises stress and z-axis stress contours of the conductive adhesive interconnection joint array were constructed, and the critical adhesive joint was identified. The von Mises stress, z-axis stress, and maximum equivalent plastic strain of the critical adhesive joints for the cured conductive adhesives with 50 and 60 wt% silver filler content under different drop heights were acquired. Results showed the dependence of conductive adhesive interconnection joints on drop height and silver filler content.