A semiconductor device is disclosed, which includes an insulating layer and an interconnection layer having a conductive layer provided over the insulating layer. The interconnection layer is patterned by photolithography. The device further includes a cap-metal layer, which is deposited on the conductive layer and suppresses reflection of light beams at the time of patterning the interconnection layer. The cap-metal layer has any one of the following structures: a double-layered structure having a titanium nitride layer and a titanium layer located between the titanium nitride layer and the conductive layer; a double-layered structure having a titanium nitride layer and an aluminum-titanium alloy layer located between the titanium nitride layer and the conductive layer; and a single-layered structure consisting essentially of an aluminum-titanium alloy. These design ensure accurate interconnection patterning in the photolithography, and provide improved EM and SM immunities of the interconnection.