Analytical Study of Impurity Doping Effects on Electromigration of CU Interconnects by Employing Comprehensive Scattering Model

We investigated the impurity (Al) doping effect on resistivity of damascene Cu interconnects with decomposing into surface, grain boundary, and impurity scattering factors by employing comprehensive scattering model. The surface scattering is dominant for resistivity increasing. Electromigration-induced Cu drift is suppressed as Al concentration increases. The electromigration lifetime is improved by suppression of the Cu diffusion due to piled-up Al at the top surface of Cu interconnects.