Molding compounds are key materials to deliver well packaged reliable IC’s for demanding applications, such as automotive electronics. With shrinking sizes of IC’s and the increased requirements with respect to loading conditions, application environment and lifetime, the reliability of the packaging becomes increasingly important. The performance of the package is closely connected to the morphology and the microstructure of the molding compound as well as to the processing conditions during molding. The first issue is a factor which is often overlooked and not always well understood. In our paper we will elaborate on the micro-mechanical mechanisms that play a role in cracking and delamination of the composite molding compound. We will introduce a multi-scale modelling approach as tool for understanding of the conditions and constraints during molding and use of packaged IC’s. Consequently, such an approach can serve as a design tool for next generation molding compounds.