Characterization of viscoelastic behaviour of a molding compound with application to delamination analysis in IC packages

Over the glass transition temperature, molding compounds strongly exhibit viscoelastic behavior which causes their Young's moduli to be not only temperature-dependent but also time-dependent. In the present study, the stress relaxation test is used for the characterization of the viscoelasticity of an epoxy molding compound. The viscoelastic properties of the epoxy molding compound are determined in terms of Prony coefficients, relaxation time and time-temperature shift factors. Furthermore, the effect of viscoelasticity on the delamination in IC packaging is investigated