In order to describe the change of noise signal in Al thin-film during electromigration process and its invalidation mechnism, correlation dimension was used in the electromigration noise signal analysis. Through calculating correlation dimension of electromigration noise signals attained by our experiment, the result showed that the main component of noise signal changed from stochastic to determinate during electromigration process, indicating that the noise changed from stochastic signal to chaotic dynamic signal. Dispersion theory was used to explain the above phenomenon. During vacancy dispersion, the main cause of noise is the stochastic dispersion of vacancies; during the process of vacancies accumulation to void nucleation, the main cause of noise is the change from stochastic dispersion to ballistic chaotic cavity transport. Compared with traditional parameters, the result showed that correlation dimension could be used to predict the invalidation of electromigration damage.