Microstructure and thermophysical characterization of innovative plastic materials for power electronics

Encapsulation of power electronic modules is necessary to protect the different components from (harsh) environments, such as moisture, chemicals or gases and from mechanical stresses. The reliability of thermoplastic housing materials depends significantly on the microstructure properties of the bulk material and the properties of the single components, e.g. fiber fillers. The thermophysical and electrical failure mechanism of the plastic materials can influence the reliability of the single electrical components, which are directly or indirectly connected to the device package. In our study we investigated thermoplastic materials of two suppliers that are innovatively used as housing materials for power modules. Uniquel specimen were manufactured by injection molding and analyzed by high resolution Scanning Electron Microscopy (SEM) and thermophysical analyses for investigation of microstructure, water absorption, water permeability, mechanism of water storage and ion conductivity. Our results show that nominal identical materials produced by two different suppliers significantly vary in their thermos-physical properties caused by a different micro structure.