Improved Methodology for Parasitic Characterization of High-Performance Power Modules

The accelerating commercialization of wide bandgap technology has led to increased demand for accurate characterization of parasitic impedances within packaging structures such as multichip power modules. However, the accuracy of known methods is not sufficient to characterize high-performance modules which have extremely low parasitics, with impedance values near the measurement floor of common instrumentation. To address this characterization gap, this article introduces a custom measurement methodology that utilizes a general-purpose instrument and fixture but reduces systematic and stochastic error to an acceptable level through an emphasis on rigorous calibration and measurement consistency. Additionally, fixture compensation is performed via post-processing in MATLAB to improve measurement fidelity via statistical techniques. The proposed methodology is validated with a series of known test samples in the impedance range of interest. Finally, the methodology is used to perform parasitic characterization of a high-performance power module with commutation loop inductance previously reported to be less than 1.6 nH.