Sustained High-Temperature Vibration Reliability of Thermally Aged Leadfree Assemblies in Automotive Environments

Abstract

Applications in downhole drilling, automotive industry and avionics industry require exposure of electronics to sustained high temperatures electronics combined with vibration loads. In these conditions, maximum temperature can exceed 200 °C and vibration G-level up to 10G. Combined effect of elevated temperature and vibration can cause faster failure in electronics components. In this study, reliability for SAC105 and SAC305 electronics operation at elevated test temperature and vibration has been studied. Pristine and aged test board with lead-free SAC daisy chain CABGA packages have been subjected to harmonic vibration at their 1st natural frequency at three test temperatures (25°C, 55°C and 155°C) and vibration with amplitude of 5G, 10G and 14g. Test boards were exposed to isothermal aging conditions at 150°C for 60 days. Hysteresis loop and plastic work density of critical solder joint extracted using FEA based global and local method. S-N curves were obtained for test vehicle. Failure mode analysis has been done for test board. Anand Viscoplasticity material data from the prior studies by the authors have been used to capture the high-strain rate temperature dependent aging behavior of the solder joints. A new model has been proposed to predict the high frequency fatigue life under simultaneous temperature-vibration.