Further Enhancement of Electro-migration Resistance by Combination of Self-aligned Barrier and Copper Wiring Encapsulation Techniques for 32-nm Nodes and Beyond

To further enhance electro-migration resistance, we applied a self-aligned barrier technique to Cu wiring encapsulated with a MnO barrier. This combination of the self-aligned barrier and encapsulation techniques increased maximum current density to 9 times that of the conventional one. The Cu wiring fabricated by the combination of the two techniques also had greater resistance to stress-induced voiding set off by thermal stress. The combination of the two techniques also enhanced the lifetime of time-dependent dielectric breakdown by a factor of 160.