Fatigue behavior and effect of crack propagation in lead free solder in microelectronic packaging

We have observed stress softening behavior of SAC 305 bulk solder bars tested at various stress levels and frequencies at room temperature. The behavior can be described by crack propagation through these as well as microstructural interactions within the material. Continued testing at other stress levels and temperatures will be conducted to further understand low cycle fatigue in SAC 305 to eventually improve the reliability of devices using SAC 305.