Discrete Phase Model (DPM) study of nano-reinforced Lead Free Solder Sn-3.0Ag-0.5Cu (SAC305)

This paper presents a preliminary study of the interaction between two models of numerical simulation namely volume of fluid (VOF) and discrete phase model (DPM). The multiphase-DPM model is capable of tracking the trajectory of the TiO2 nanoparticles that has been doped in the lead free solder Sn-3.0Ag-0.5Cu (SAC305). The current model was developed based on passive surface mount component 01005 capacitor that undergoes conventional reflow process. The trajectory of the nanoparticles at 0.01, 0.05 and 0.15wt% in the molten solder is shown in the flow front of the wetted molten solder. At 0.05wt% of nanoparticles, good dispersion of nanoparticles, pressure distribution and wetting time was found. The difference in wetting time are about 3.76% and 0.46% for 0.05wt% and 0.15wt% compared to 0.01wt% nanoparticle. The trajectory of the nanoparticles are shown to move along with the wetting formation of the molten solder. The pressure distribution and velocity vector of the different weight percentage of nanoparticles are also be studied. Higher pressure distribution is found at the capacitor area and intermetallic compound (IMC) region. The higher pressure distribution projected to reduce the micro void formation and optimize the reliability of the solder joint. (paper)