Research on IGBT Chip Bond Wire Lift-Off Fault Detection Method Based on Decoupling of Time Domain Reflective Signal Feature

Based on the principle of reflectometry, this paper proposes and constructs a spread spectrum time domain reflectometry (SSTDR) signal testing scheme and system platform for insulated gate bipolar transistor (IGBT) device-level detection. Subsequently, a signal pre-processing algorithm for the sampling aliasing phenomenon is proposed based on the platform's signal transmission model. Building on this foundation, this paper conducts a modeling study on the dynamic impedance analysis of devices under IGBT chip bond wire fault conditions from two aspects: the signal parameters and the transmission path. Subsequently, a bond wire lift-off fault detection method based on the mapping correlation between signal, impedance, and fault is proposed. The experimental results demonstrate that the proposed method can achieve independent detection of bond wire lift-off faults in IGBT chips and FWD chips based on signal feature decoupling. This provides a scientific theoretical basis for the quantitative assessment of bond wire degradation trends.