This paper presents a proof-of-concept study on nondestructive detection and localization of bond wire lift-off in insulated-gate bipolar transistors (IGBTs) using frequency-domain magnetic-field scanning. Unlike conventional time-domain approaches, the proposed method measures magnetic-field at selected excitation frequencies using a passive printed circuit board (PCB) based magnetic-field probe (MFP). The passive MFP requires neither a magnetic-sensor chip nor its associated biasing and signal-conditioning circuitry, offering a low-cost sensing approach with potential for compact integration and array implementation. The MFP measures the magnetic-field distribution above the bond wires to assess their health status. Simulations were performed on four closely spaced IGBT bond wires and a structurally similar microstrip-line (MSL) equivalent model that reproduced the magnetic-field response of the bond-wire model. Comparisons between healthy and lift-off conditions enabled accurate fault localization in both models. The MSL model was further validated experimentally, and the measured results agreed well with the simulations. These results provide a proof-of-concept demonstration of frequency-domain magnetic-field scanning for detecting and localizing IGBT bond-wire lift-off faults, indicating its potential for future bond-wire NDT applications.

bond wire,insulated-gate bipolar transistor (IGBT),lift-off,non-destructive testing (NDT),frequency-domain magnetic-field scanning,condition monitoring