A semiconductor device and the method of fabricating the semiconductor device include a semiconductor substrate and a plurality of conductor films formed on the substrate. Each of the conductor films is made of aluminum alloy including at least one element selected from palladium and platinum and, more preferably, further including at least one element selected from lithium, beryllium, magnesium, manganese, iron, cobalt, nickel, copper, lanthanum, cerium, chromium hafnium, zirconium, cadmium, titanium, tungsten, vanadium, tantalum, and niobium, with a protective film which includes oxide of the selected one of palladium and platinum being formed on the side wall of the conductor film.