Effects of Mn nanoparticles on wettability and intermetallic compounds in between Sn-3.8Ag-0.7Cu and Cu substrate during multiple reflow

In this research, the effects of Mn nanoparticles on wettability and interfacial intermetallic compounds in between Sn-3.8Ag-0.7Cu (SAC) solder and copper (Cu) substrate was investigated. The nanocomposite solders were fabricated by mechanical mixing of SAC solder paste with Mn nanoparticles. The melting characteristic of the solders was characterized by differential scanning calorimeter (DSC). The solder pastes were reflowed in a reflow oven at 250°C for 60 seconds. The spreading rate and contact angle of the solders was calculated to measure the wettability. The solder joints were characterized by field emission scanning electron microscope (FESEM) and energy dispersive X-Ray (EDX). It was found that with the addition of Mn nanoparticles the total IMC thickness decreased after first and six times reflow. The Cu₃Sn layer was not affected with the addition of Mn nanoparticles. However, some probable mechanism is suggested to explain the effect of Mn nanoparticles on SAC solder.