A semiconductor device has an active element structure formed on a semiconductor substrate. The active element has a connection region formed on a surface of the semiconductor substrate. An insulating film is formed on the semiconductor substrate. A connection hole is formed in the insulating film, and has a bottom connected with the connection region. An interconnect trench is formed in the insulating film, and has a bottom connected with the connection region. A first conductive film is filled in a first region ranging from the connection region in the connection hole to a first height, and is composed of an alloy containing CoW or NiW. A second conductive film is formed in the interconnect trench, and is electrically connected with the first conductive film.