Modeling of IC Socket Contact Resistance for Reliability and Health Monitoring Applications

We present a methodology based on the physics of failure, and the sequential probability ratio test, for modeling and monitoring electrical interconnects in health monitoring, and electronic prognostic applications. The resistance behavior of an electrical contact was characterized as a function of temperature. The physics of failure of the contact technology were analysed. A contact resistance model was selected, and its parameters were fitted using the temperature characterization data. The physics of failure model was evaluated with a reliability application (temperature cycle test), and was found to produce estimation errors of < 1 mOmega of during a training period. The temperature and resistance of ten sample contacts were continuously monitored during the temperature cycle test, identifying the maximum temperature and resistances for each cycle. Using the physics of failure model, maximum resistance estimates were generated for each test sample. The residual between the monitored and estimated resistance values was evaluated with the sequential probability ratio test. The method was shown to overcome the issues of traditional threshold-based monitoring approaches, providing accurate resistance estimates, and allowing the detection of abnormal resistance behavior with low false alarm and missed alarm probabilities.