A method includes forming a semiconductor device, forming a combination of a connection-level dielectric layer and a connection-level metal interconnect structure over the semiconductor device, forming a line-and-via-level dielectric layer over the connection-level dielectric layer, forming an integrated line-and-via cavity through the line-and-via-level dielectric layer over the connection-level metal interconnect structure, selectively growing a conductive via structure consisting essentially of an elemental metal that is not copper from a physically exposed conductive surface located at a bottom of the via portion of the integrated line-and-via cavity without filling a line portion of the integrated line-and-via cavity, and forming a copper-based conductive line structure that includes copper at an atomic percentage that is greater than 90% in the line portion of the integrated line-and-via cavity.