Reliability evaluation of SnAgCu/SnAgCuCe solder joints based on finite element simulation and experiments

Abstract

PurposeThe purpose of this paper is to numerically evaluate the reliability of SnAgCuCe solder joints compared with that of SnAgCu. A trace amount of the rare earth (RE) element Ce was added into SnAgCu solder in order to improve the reliability of lead‐free solder joints, which was evaluated based on finite element simulation and experiments.Design/methodology/approachA finite element method and an Anand constitutive model were employed to analyze the reliability of SnAgCuCe and SnAgCu solder joints in fine pitch quad flat packages under thermal cycling. The mechanical properties and reliability of solder joints were characterized by using thermal fatigue and creep tests, while the microstructure of the solder alloy and SnAgCu/SnAgCuCe solder joints were also investigated in the experimental procedure.FindingsThe simulation results indicated that SnAgCuCe solder joints had better reliability than SnAgCu. In addition, the experimental results accorded well with those of simulation, the thermal fatigue property and creep resistance of solder joints was increased by adding cerium. SnAgCuCe alloy can get its microstructure refinement improved and the thickness of the intermetallic compound layer at the solder/Cu interface decreased significantly compared to that of SnAgCu.Originality/valueThe findings provide certain guidelines to the reliability evaluation of solder joints when applying novel RE containing solder alloys in practical electronics industry applications. In the meantime, the reason for the superior reliability of SnAgCuCe solder joints can be explained from the property and microstructural point‐of‐view.