Real-time in situ X-ray micro-beam measurements were made of electromigration-induced Cu redistributions and of the associated local stress variations in wires. The data were obtained by combining X-ray microtopography with energy-dispersive fluorescence analysis, and covered the early and late stages of electromigration as well as the post-relaxation stage at high temperature when the current ceased. Both the Cu concentrations and the stresses exhibited unexpected local variations. These were suggested to reflect the local film/substrate interface or microstructural integrity.

Real-time X-Ray Microbeam Characterization of Electromigration Effects in Al(Cu) Wires. P.C.Wang, I.C.Noyan, S.K.Kaldor, J.L.Jordan-Sweet, E.G.Liniger, C.K.Hu: Applied Physics Letters, 2001, 78[18], 2712-4