The electromigration failure distribution: The fine‐line case

摘要

The electromigration failure distribution for fine‐line interconnects is unknown, but expected to be strongly affected by microstructure. Results from tests on lines with controlled grain sizes and distributions of grain sizes argue for a series model of failure elements in fine lines. A new statistical model of electromigration is developed based on an extension of the failure model of Shatzkes and Lloyd J. Appl. Phys.59(1986) incorporating the statistics of microstructure and concomittant variations in the activation energy for grain‐boundary diffusion. The resulting electromigration failure distribution is well‐approximated by a multilognormal distribution in the fine‐line case. This approach results in a failure distribution calculated from first principles which, unlike the lognormal distribution, is scalable.