The Intermixing Study of Cu/Ru Interface in Dual-damascene Scheme for Advanced Interconnect

Various novel technologies for Cu metallization were used to achieve barrier or liner less at via bottom. It was demonstrated that barrier thickness at via bottom is more important contributor to the via resistance, compared to the liner thickness. In terms of the integration for both Cu extension and alternative conductor interconnects, the interface issues between Mx+Vx-1 Cu and Mx-1 Ru were studied by ET measurement and the package-level EM reliability tests. The results confirmed that Mx+Vx-1 Cu dual-damascene metallization used in this works is very robust and healthy and also very stable properties of Mx-1 Ru does not cause the intermixing or diffusion at interfaces.