Reliability of Indium Solder for Cold Temperature Packaging

A failure model has been developed for indium die attach fatigue in extreme cold temperature environment applications, such as distributed control systems for planetary exploration. The model contains both a stress component, which is based on the packaging structure, and a damage component, which is based solely on the material properties. The stress model is developed for a wire bonded, hermetic ceramic module containing a SiGe hetero-junction bipolar transistor intended for use in a lunar base. The model was calibrated using results from −196°C to 125°C thermal shock testing.