Study On The Reliability of Lead-Free Solder Joint Assemblies Under Combined Effects of Vibrations & Extended High-Temperature Exposure

Abstract Energy-based life prediction models of PCB-package assemblies under new doped solders are not available. In this work, novel SAC-Q doped solder is under study for preparing and testing of PCB-package assemblies under various conditions such as ambient temperatures up to 150°C and harmonic vibration loads, 5g and 10g. First natural frequencies of test boards were measured by both experimental and FEA-based modal analysis while 2D DIC was used to extract displacement data. Weibull distribution analysis was performed to extract the characteristic lives under various test conditions, including different temperatures and vibration loads. A damage model has been developed for the life prediction of the expected reliability of electronic assemblies under high-temperature vibration. The damage model can be used to assess the effect of accrued finite element plastic work on the expected cyclic life under aging temperature, aging time, and operating temperature. The damage model has been validated with experimental data. FEA was conducted to simulate the harmonic vibration loading of the PCB-package assemblies considering viscoplastic behavior of solder joints using previously extracted Anand model constants. Extracted hysteresis stress-strain curves and accumulated plastic work densities were used in developing an energy-based life prediction model that can predict the characteristic life of unaged and thermally aged PCB-package assemblies under different test conditions.