Embodiments described herein relate generally to one or more methods for forming an interconnect structure, such as a dual damascene interconnect structure comprising a conductive line and a conductive via, and structures formed thereby. In some embodiments, an interconnect opening is formed through one or more dielectric layers over a semiconductor substrate. The interconnect opening has a via opening and a trench over the via opening. A conductive via is formed in the via opening. A nucleation enhancement treatment is performed on one or more exposed dielectric surfaces of the trench. A conductive line is formed in the trench on the one or more exposed dielectric surfaces of the trench and on the conductive via.