Intermittent operating life results for different control strategies

Intermittent operating life test is an important method to characterize the lifetime and package reliability of power semiconductor devices. The control strategy is a very important feature of the intermittent operating life test. Intermittent operating life tests with identical start condition but different control strategies (temperature control strategy and time control strategy) have been performed, which have been conducted on specially assembled test equipment with ultimate control of all test parameters. The test results under these two different control strategies are analyzed and discussed. Failure analysis is also used, to understand the failure mechanisms induced by intermittent operating life tests. The changes of thermal resistance with intermittent life cycle number are compared under two control strategies. The results show, that time control strategy is more severe than temperature control strategy. The lifetime of power devices is longer under temperature control strategy. And the thermal resistance increases relatively larger by time control strategy.