It was found that a stress field which assisted the electromigration flux could be created when a polygranular cluster was placed away from a via; due to stresses which existed between the via and the cluster. In this situation, in spite of the slower diffusion kinetics in bamboo grains, the electromigration flux divergences at the via end would be larger than when the cluster was just below the via. This implied that the line should fail faster when the via was not over the cluster than when it was. The incubation time, before interaction between via and cluster, depended strongly upon the distance between them.

Electromigration-Induced Stress Interaction between Vias and Polygranular Clusters. Y.J.Park, Y.C.Joo: Scripta Materialia, 2001, 44[10], 2497-501