Quantification-Enabled Failure Mode Separation for IGBT Module Package Degradation Assessment

Insulated-gate bipolar transistors (IGBTs) are critical elements in power electronic system, and their health directly affects system reliability. Accurate degradation assessment is hindered by the strong coupling between bond-wire and solder layer degradation. This paper proposes a reliability-oriented quantitative degradation assessment method based on wear-out failure mode separation. It decouples bond-wire and solder layer effects using two diagnostic features: the on-state voltage drop at the intersection current of the IGBT I–V curve, and the on-state voltage drop at the peak current. The proposed method can independently quantify bond-wire and solder layer faults, enabling fault separation and assessment of degradation level. The relationship between the intersection current point in the hysteresis curve and the thermal response was investigated. The case study H-bridge converter demonstrates that theoretical and experimental wear-out degradation level errors of bond-wire and solder layer do not exceed 4.6% and 5.0%, respectively. The proposed method provides a quantitative wear-out degradation estimation tool for high-reliability applications, supporting online condition assessment and optimized maintenance decisions.