A Comprehensive Study of Solder Joint Reliability Dependent on Temperature Cycling Profiles and Material Selections with Emphasis on an Improved Solder Fatigue Lifetime Model

The significance of lifetime estimation is increasing as product applications and the necessary reliability levels become more varied. The Norris-Landzberg (N-L) model, originally developed for SnPb solder, has been widely utilized in the industry to estimate solder fatigue lifetimes. However, SnPb solder is now rarely used due to environmental regulations and various literature data has shown that the ramp rate dependency of the solder fatigue lifetime differs between SnPb and lead-free solder. Therefore, we have developed a newly improved acceleration model through a design of experiments (DOE) evaluation of various temperature cycling (TC) conditions and material combinations. We also investigated the material factors and failure mechanisms that play an important role in determining the reliability of solder joints.