Modeling of Electromigration Failure Distribution of Cu Vias: Critical Current Density Effects and Reliability Extrapolation Procedures

In this study, we examine the effects of void morphology and critical current density (jc) on the electromigration failure distributions of Cu/low-k dual damascene vias. Cu dual damascene vias exhibit multiple modes of electromigration-induced voiding and reliability is strongly dependent on the morphology of voids. We have developed a model of failure for DC and pulsed DC currents that allow prediction of failure time distributions for vias taking into account void morphology. We obtain good agreement between the model predictions and experimental data for all observed void morphologies.