Evaluation of an electrical method for detection of die attach imperfections in Smart Power Switches using transient thermal FEM simulations

A method for detection of die attach imperfections in smart power switches is evaluated using non-linear transient thermal FEM simulations and measurements. This method employs smart functions of SPS devices such as over-current and over-temperature protection. The protective thermal shut down function is triggered by the temperature of the integrated temperature sensor. The temperature rise depends on power dissipation in the device and on the thermal junction to ambient impedance which is inter alia related to the die attach imperfection. The evaluation is performed on a two channel smart power switch. Results are focused on practical relevance and sensitivity of this method to the influence of die attach thickness and die attach voids.