A comprehensive look at PVD scaling to meet the reliability requirements of advanced technology

The reliability of interconnects continues to be a formidable challenge as dimensions shrink from generation to generation. In this paper we demonstrate barrier/seed scaling, enabled by HCM^reg IONX PVD technology. We report high electromigration activation energy of ~ 1 eV, and J_max > 6 MA/cm², exceeding the ITRS 2007 requirements for the next several generations by a wide margin. Thinner barrier/seed with increased barrier etchback is shown to increase electromigration lifetime. Via stress migration results indicate that high barrier etchback is beneficial to reliability. TDDB results show a strong positive effect of barrier etchback on lifetime. We find that breakdown voltage for thinner barrier/seed is higher than that of the control. Breakdown voltage further increases with increased barrier etchback. For TDDB, the field acceleration coefficient, gamma, improves with increased etch back from 4.3 (MV/cm)P^-1 to 10 (MV/cm)^-1 and the expected lifetime at operation conditions is improved by several orders of magnitude, exceeding requirements by a wide margin. This comprehensive study of PVD scalability proves a process space that provides the reliability margin necessary for continuing technology scaling for future generations.