Detection of IGBT Bond-Wire Lift-off Using Acoustic Pressure Scattering

This paper investigates the detection of damaged bond wires in Insulated Gate Bipolar Transistor (IGBT) modules through the application of acoustic pressure scattering techniques. IGBTs are critical components utilized in systems such as renewable energy installations and high-voltage direct current (HVDC) transmission systems. Within these modules, bond wires serve to connect the semiconductor die to external terminals while providing structural support. However, these wires are susceptible to cracking or detachment under high-stress conditions induced by heavy electrical currents and temperature fluctuations, leading to potential module failures. The proposed study employs COMSOL Multiphysics to examine the effectiveness of sound waves and acoustic pressure scattering in detecting these compromised bond wires. A detailed IGBT model was constructed, incorporating 16 bond wires, and subjected to various defect scenarios at two distinct frequencies: 5 MHz, and 30 MHz. The scenarios included a module with no defects, a single defective wire, five defective wires, and ten defective wires. Comprehensive acoustic scattering analyses were conducted, capturing the pressure amplitudes around the bond wires in a two-dimensional format. The objective of these analyses is to evaluate the influence of different defect severities on the acoustic signatures and to identify the optimal frequency for accurate defect detection. It was observed that the 5 MHz frequency provides more distinct insights into the quantity of defects when compared to the 30 MHz frequency.