The evolution of stresses in confined, layered, stud-terminated, pure metal and alloy interconnects was studied. Failure times were estimated by using various failure criteria which were associated with differing failure modes for wide ranges of line-lengths and current densities. The simulation results could be conveniently displayed by the construction of failure-mechanism maps which demarcated the domains of predominance of various failure modes. Such mechanism maps were constructed for several failure criteria, and illustrated regimes of line immortality, void-nucleation limited failure, void-growth limited failure, and compressive failure as a function of line-length and current density. The effects of changes in failure criteria, geometry and composition were studied for representative interconnect stacks under accelerated and service conditions. The failure maps could be used to provide an overview of the predicted reliability behavior, to assess how data from accelerated tests could be accurately scaled to service conditions and to predict the effects of changes in interconnect and shunt-layer materials and dimensions upon interconnect reliability.

Mechanism Maps for Electromigration-Induced Failure of Metal and Alloy Interconnects. V.K.Andleigh, V.T.Srikar, Y.J.Park, C.V.Thompson: Journal of Applied Physics, 1999, 86[12], 6737-45