Partial Discharge Analyses of DBC Substrates

Abstract:
Direct Bonded Copper substrates are essential parts of modern power electronic modules. These metallized ceramic substrates show excellent thermal and electrical insulation properties which are required for state of the art wide-bandgap semiconductors. However, the ceramic-metal-multilayer structure complicates substrate characterization in terms of electrical characteristics. Partial Discharge measurement, as already established in high voltage technology, is evaluated in this work regarding reliability diagnosis. Possibilities and limitations of the proposed measurement method are demonstrated by means of two measurement series of different mechanical stress and degradation stages. Fundamental measurements show significant correlations between substrate degradation and PD metrics. Pulse Sequence Analysis of Partial Discharge Measurement data shows promising results regarding the classification of weak points in Direct Bonded Copper substrates.