Abstract
Two methods for calculating the fracture parameters characterizing interfacial delamination between dissimilar materials in LSI plastic packages with either Cu alloy (Cu-2%Sn) or alloy 42 (Fe-42%Ni) leadframe were studied. One method uses relative displacement method proposed by Yuui et al. to derive stress intensity factor and the other derives the energy release rate of interfacial delamination using Irwin's crack closure method. It was found that the value of total energy release rate G derived from Irwin's crack closure method was consistent with that calculated from stress intensity factors using relative displacement method. In Irwin's crack closure method, it was required that opening and shearing unit load in the computation of local compliance's should be applied to nodes which were located more than onefifth of normalizing length away from delamination tip to avoid oscillatory singular displacement field near delamination tip.
