A multilayered wiring is formed in a prescribed area in an insulating film that is formed on a semiconductor substrate. Dual damascene wiring that is positioned on at least one layer of the multilayered wiring is composed of an alloy having copper as a principal component. The concentration of at least one metallic element contained in the alloy as an added component in vias of the dual damascene wiring is determined according to the differences in the width of the wiring of an upper layer where the vias are connected. Specifically, a larger wiring width in the upper layer corresponds to a higher concentration of at least one metallic element within the connected vias. Accordingly, increases in the resistance of the wiring are minimized, the incidence of stress-induced voids is reduced, and reliability can be improved.