Interfacial delamination is a cause for concern in electronic packages consisting of several dissimilar material systems. Even if current designs do not experience delamination as a failure mode, it is necessary to understand the effect of material and geometry properties on interfacial stresses to lower the potential of interfacial delamination in future designs. The objectives of this work are to model current and future versions of a novel peripheral array package and examine the possibilities for interfacial delamination.
This paper employs 2D plane-strain parametric finite-element models to study interfacial stresses. Element birth and death features have been used to simulate the complete manufacturing process of the package. The effect of encapsulant material properties and die-attach properties on interfacial stresses is discussed. These results will serve to aid in the selection of appropriate die attach and encapsulant materials for enhanced future designs. Delamination is also studied from a fracture mechanics perspective. A separate 2D model is constructed with a crack inserted between the encapsulation/backplate interface. Principal stress vectors are plotted along the interface to qualitatively determine the potential for crack extension. Crack growth is simulated by incrementally extending the length of the crack in the mesh.