Bruchmechanische Analyse von viskoelastischen Werkstoffen in elektronischen Bauteilen

Cracks inside polymeric packaging materials which are used for protection and isolation of electronic components, can lead to failure of the whole system. Therefore the understanding of crack initiation and propagation becomes vital for the design of reliable microsystems and a methodology is developed that enables the fracture mechanical analysis of cracks. As polymeric packaging materials show viscoelastic material behaviour, a characterisation method is being developed to describe the multi-axial stress-strain relationship. In this context the question arises about an adequate fracture criterion. Therefore different fracture criteria for viscoelastic materials are reviewed and compared. They are evaluated with respect to thermo-mechanical loading. After that the results of this analysis are applied to a demonstration case. Simulation and experiment are compared and a good correlation is demonstrated