Electromigration failure due to interfacial diffusion in fine Al alloy lines

Abstract

Damage formation at grain boundary junctions has long been recognized as the dominant electromigration failure mechanism in metal lines. We report the results of drift-velocity experiments on fine lines with no reservoirs and find that the interfacial mass transport, along the edges of the lines, is faster than that along grain boundaries. This causes mass depletion at the cathode end of the line, leading to electromigration failure. The result demonstrates a new failure mechanism due to electromigration in submicron lines with bamboo grain structures.