Electrical characterization of a pressed contact between a power chip and a metal electrode

This study deals with the power electronics packaging and the needs for additional knowledge about electrical pressed contact behavior. For this, a measure bench has been realized. It is able to characterize the pressed interface between a metal electrode and a power chip as a function of the clamping force (0-8000N) and the temperature (up to 100°C). First measurement results show that the electrical contact resistance is negligible compared to the chip on-state voltage. Second measurement results show that the high value of the chip metallization resistance masks also the contact resistance. Finally, it appears that it is necessary to estimate the chip contact zone influences on the current repartition. Then a method based on both, the use of a chip model and the measurements directly on the chip, has been developed. It is able to look for the steady state current repartition in the chip as a function of the contact zone and the chip metallization physical parameters.