Prediction of Statistical Distribution of Vibration-Induced Solder Fatigue Failure Considering Intrinsic Variations of Mechanical Properties of Anisotropic Sn-Rich Solder Alloys

The unknown statistical distributions of two effective elastic properties of Sn-3.0Ag-0.5Cu solder joint of leadless chip resistors (LCR) are determined while considering the statistical variations of six other input variables including die thickness, solder joint height, termination length, and thickness and elastic moduli of a printed circuit board. The cyclic bending test results of the LCR assemblies are used to obtain the probability density functions of the effective elastic properties of the SAC305 solder by statistical model calibration in conjunction with an advanced uncertainty propagation analysis. The statistical distribution of cycles to failure of the same LCRs subjected to a different loading level is predicted accurately by the calibrated model, which corroborates the validity of the proposed approach.