Critical initial void growth for electromigration: Stress modeling and multi-link statistics for Cu/low-k interconnects

This paper investigated the initial void growth that determines the electromigration failure time for Cu/low-k interconnects. A method to derive the initial void growth rate prior to line failure by analyzing the resistance traces was developed. The statistical data from multi-linked structures show a linear relationship between the void growth rates before and after failure. An extended the Korhonen model was developed taking into account the stress effect on void growth for Cu interconnects. The model was able to account for the observed EM statistics, thus suggesting that the effect of stress should be included for EM lifetime extrapolation.