Conclusions about the expected reliability of an electronic module, a component or an interconnection can be obtained during experiments by statistical tests or, to be exactly, by observed failures during those tests. Such failures should of course preferably happen after a long operation time only. “Storage experiments”, which emulate the loads acting on such modules etc., have to provoke failures within a limited period compared to the normal operation. That can be reached by accelerated changing of the load situation and/or by excessive load. It is necessary to ensure, that this load does not lead to completely different material behaviour and hence to different defects and failure mechanism.
During temperature cycling tests (TCT) specimen are heated up and cooled down cyclically. The changing speed between the different temperature levels is moderate.
During temperature shock test (TST) specimen are moved between the upper and the lower temperature level within seconds. Then the stay on that level for a while.
Isothermal storage of specimen works on higher but constant temperature levels.
During climate storage specimen are stored at slightly higher, but mostly constant temperatures. In addition, there is a strong humidity load on the specimen at the same time.
Vibration tests put a high frequency mechanical vibration load and hence an acceleration force on the specimen. The stimulation can be homogeneous or superposed from different frequencies and amplitudes.
In real operation electronic modules are often exposed by multiple different loads. Therefor more and more combined tests are applied.