Characterization of electromigration parameters in VLSI metallizations by [formula omitted] noise measurements

Abstract

Low-frequency (LF) noise measurements were performed on aluminum thin films biased at current densities of 5 × 10 5 to 3 × 10 6 A/cm 2 at different temperatures up to 200°C. Correlation between the mechanisms causing these LF fluctuations and electromigration was investigated. Contrary to the 1/ f 2 form observed by other researchers, we observed 1/ f γ noise spectra where γ varied between 0.8 and 1.5. Through the Arrhenius plot of noise power spectral density, activation energies ranging from 0.60 to 0.69 eV have been obtained which agree with activation energies obtained through 1/ f 2 noise measurements. These values also agree with activation energies measured by conventional stressing techniques and are in the same range as electromigration mechanisms originating from grain boundaries. Through the current dependence of γ, and the current dependence of the noise power magnitude, we attempted to predict electromigration damage and time-to-failure. For the first time, we incorporated the current dependence of the spectral form in the analysis of noise magnitude for electromigration.