Field failure mechanism and improvement of EOS failure of integrated IGBT inverter modules

Abstract

In this paper, we have proved that the soft damage from human body ESD can actually cause EOS damage, while integrated IGBT inverter modules (or intelligent power modules) are operating. Failure mechanism was defined as a latchup phenomenon by ESD damage leakage. Failure modes of each failed IGBT inside two integrated IGBT inverter modules were soft and hard burnout, respectively. To determine the failure mechanism, we have done fault tree analysis. From this analysis, we could conclude the main factor as the ESD event between device ESD immunity and PCB assembly line. In addition, from the PCB assembly line, we have identified damage samples due to an ESD event. Based on this result, we have implied ESD on IGBT and intentionally caused a leakage, then applied the device to the system. After an aging test, we could reproduce soft burnout and hard burnout.