Electromigration during accelerated testing could induce plastic deformation in apparently undamaged Al interconnect lines as recently revealed by white beam scanning X-ray micro-diffraction. A first quantitative analysis was made here of the dislocation structure generated in individual micron-sized Al grains during an in situ electromigration experiment. Laue reflections from individual interconnect grains exhibited pronounced streaking during the early stages of electromigration. It was demonstrated that the evolution of the dislocation structure during electromigration was highly inhomogeneous and resulted in the formation of unpaired randomly distributed dislocations as well as geometrically necessary dislocation boundaries. Approximately half of all unpaired dislocations were grouped within the walls. The misorientation created by each boundary and density of unpaired individual dislocations was determined. The origin of the observed plastic deformation was considered in view of the constraints for dislocation arrangements under the applied electric field during electromigration.

Quantitative Analysis of Dislocation Arrangements Induced by Electromigration in a Passivated Al-0.5wt%Cu Interconnect. R.I.Barabash, G.E.Ice, N.Tamura, B.C.Valek, J.C.Bravman, R.Spolenak, J.R.Patel: Journal of Applied Physics, 2003, 93[9], 5701-6