A study of multiple singularities in multi-material wedges and their use in analysis of microelectronic interconnect structures

The nature of the singular stress field at bi-material and multi-material wedges with de-bonded or bonded interfaces is investigated in this paper with the aim of relating singular stress field to failures in microelectronic interconnect structures. The dependence of the strength and the number of the singularities on the relative material behavior as well as the wedge angle is extensively analyzed using planar isotropic elasticity. The procedure is used to analyze modern copper interconnect structures; the orders of singularities and angular functions are asymptotically determined, based on which the stress intensity factors are calculated.