The Effect of Low Temperature Conditions on Vibration Durability of SAC105 Interconnects

Electronic assemblies are often utilized in environments in which they are exposed to significant combinations of simultaneous vibration and thermal loads. In this study, vibration durability tests and results under isothermal conditions are presented for SAC105 solder joints of CR0805 chip resistor components. The tests are performed using a specially designed multi-cantilever printed wiring assembly (PWA) containing CR0805 components. Harmonic vibration durability tests were conducted at both room and low temperatures, for multiple deflection levels. The resistance of the resistor assemblies was continuously monitored to detect fatigue degradation of the interconnects during the vibration testing. A detailed 3D transient FE analysis is conducted to examine effective solder joint strains as a result of the applied deflections at various temperatures. The measured cycles to failure and calculated strains were used to derive S-N- plots. A comparison of fatigue behaviour at room and low temperature condition is drawn. Failure analysis results are presented to elucidate the failure modes.