Description of Invention
Lead-free solders have attracted attention in electronic packaging industries as replacement for conventional Sn-Pb solders due to their ability to suppress IMC layer growth. The existence of IMCs layer at the interface plays vital role as the metallurgical bonding agent and indirectly affecting the reliability of solder joints. The growth of the IMC layer has to be controlled at an appropriate IMC thickness, so as to ensure very reliable solder joints with a good metallurgical bond. This project proposes to introduce a blocking mechanism to reduce the growth of IMC between solder and substrate by introducing reinforcements into the solder. This project work revealed that the IMC layer growth was inhibited significantly attributed to the adsorption effect of surface-active nanoparticles, decreases the surface energy of Ag3Sn and Cu6Sn5 grains. The presence of nanoparticles also acts as diffusion barriers of Cu and Sn atoms at the interface between solder and substrate. Wettability performance was improved with lower contact angle and larger spreading area. The reinforcement of nanoparticles has remarkably influenced the reliability, solderability and lifetime performance of the solder. This project exhibited that the reinforcement of nanoparticles is ideal to be implemented in electronic packaging industry.