Experimenting and modeling of catastrophic failure in electromigration-induced resistance degradation for deep submicron dual-damascene copper interconnects

The features of electromigration-induced resistance change profile are important aspects of reliability, especially for ULSI interconnect. By experimenting on 0.28 µm wide Cu dual-damascene interconnects, clear evidence of catastrophic failure is observed even when the failure criterion of only 2% resistance change is imposed. Applying theoretical constitutive law of degradation and using basic principles of generic model, constitutive equation for resistance degradation in electromigration is derived and simulated for catastrophic failure. Then real-time resistance change profile is obtained by a simple analytical model which incorporates the Nernst-Einstein relation of mass transport. The convergence of the analytical model to the generic one is also shown. The various aspects of catastrophic failure are discussed. A good correlation between the results obtained from the model and experiment are shown.