A semiconductor device is provided. The semiconductor device comprises a first wiring structure which includes a first material, and has a first width on a lowest surface in a first direction and a second wiring structure which includes a second material, is spaced apart from the first wiring structure in the first direction, and has a second width smaller than the first width on a lowest surface in the first direction, wherein a highest surface of the first wiring structure has a third width smaller than the first width in the first direction, and a highest surface of the second wiring structure has a fourth width smaller than the second width in the first direction.