Cure, temperature and time dependent constitutive modeling of moulding compounds

Moulding compounds are used as encapsulation materials for electronic components. Their task is to protect the components from mechanical shocks and environmental effects such as moisture. Moulding compounds are epoxy resins filled with inorganic (silica) particles, carbon black and processing aids. They show a clear viscoelastic behaviour which is not only temperature but also cure dependent. Due to both thermal and reaction shrinkage, moulding compounds introduce residual stresses which may eventually result in product failure. Therefore they can be considered as key materials for overall thermomechanical reliability. This paper deals with the characterization and modeling of the mechanical behaviour of such moulding compounds. The focus is on the effects of the degree of cure and the filler concentration.