A numerical model for diffusion driven gas bubble growth in molten Sn-based solder

As soldering process is a high temperature phenomenon accompanied by surface reaction kinetics, the computational model for solder bubble growth can be a strong arena for describing those aspects which are otherwise difficult to be understood through the experimental methods. In this paper, the growth of gaseous bubbles in the molten tin solder has been modeled using finite element method. The advection-diffusion and lagrangian mesh adaptation equations have been utilized to obtain the numerical solution of concentration flux and radius change for a single spherical bubble. Utilizing the axisymmetric coordinate system (2D), the final bubble diameter has been obtained to be 31.06 μm at a working temperature of 350 °C. The experimental images of the voids have been obtained from Synchrotron Radiation Imagaing Technique and Scanning Electron Microscopy. Since the diffusion limited void growth is found to increase with the greater value of working temperature whereas decrease with the higher magnitudes of viscosity and surface tension of the solder alloys, these properties need to be addressed at high temperature applications. Future works in this area include the addition of the roles of the Intermetallic Compounds and bubble interface coalescences.