Width Dependence of Electromigration Life in Al-Cu Al-Cu-Si, and Ag Conductors

The electromigration lifetimes of thin-film Al-Cu, Al-Cu-Si, and Ag conductors were measured as a function of stripe width. Both the median lifetime and the standard deviation of the lognormal failure distribution were observed to depend strongly on the stripe width; this finding indicates that a narrower stripe is less reliable. This width dependence is interpreted in terms of the microstructural characteristics of the films.