Noise and reliability in simulated thin metal films

Many macroscopic aspects of electromigration damage in thin metal films have been investigated by means of Monte Carlo simulations based on simplified physical model. The employed model, can be described as a middle-scale model, in which the physical system is modeled with a high level of abstrac- tion, without a detailed atomic physical model of the system. Among the many effects of the electromigration phenomenon, the simulator has been used to investi- gate several statistical properties of electromigration failure and the noise behaviour. Notwithstanding this simplicity, it is able to generate results in good agreement with many experimen- tal observations: the lognormal distribution of failures, dependence of the mean time to failure from stress current and film geometry, Black exponent, noise statistics. Furthermore, this simulations confirmed a significant correlation between electromigration noise in the initial phase of stress and time to failure which has been suggested by a few experimentalists. This correlation can be usefully exploited as an early indication of the onset of electromigration damage on a per-sample basis.