Abstract
Eutectic Sn-Bi alloy is acquiring significant observation in the electronic packaging industry because of its advantageous properties such as ductility, low melting temperature, and mechanical strength. Miniaturization of electronic devices requires solder paste having a low melting temperature for the fabrication of chips on printed circuit board (PCB). Surface mount technology (SMT) is a reliable technique for this purpose. This work focuses to find out the effects of cobalt nanoparticle (NP) addition into the Sn-58Bi solder joint. The reflow process was done on samples of 0%, 0.5%, 1%, and 2% cobalt addition. Then thermal aging of 0% and 0.5% of cobalt addition was done at 70 degrees C, 85 degrees C, and 100 degrees C. To characterize the specimen and determine intermetallic compound (IMC) growth, scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy were used. After the addition of Co-nanoparticles, the microstructure of Sn-58Bi was refined. The interfacial IMC thickness was also reduced after the addition of cobalt nanoparticles. Cu6Sn5 and Cu3Sn were found in the IMC of Sn-58Bi but only (Cu, Co)(6)Sn-5 was found in the IMC of Sn-58Bi-xCo nanoparticles. Growth of interfacial IMC of SN-58Bi-xCo was significantly controlled as compared to Sn-58Bi after thermal aging.