According to one embodiment, a semiconductor device includes a wiring, a first insulation film, an underlayer deactivation layer, an underlayer, a catalyst layer and a carbon nanotube. The first insulation film is formed on the wiring and includes a hole which exposes the wiring. The underlayer deactivation layer is formed on the first insulation film at a side surface of the hole, and exposes the wiring at a bottom surface of the hole. The underlayer is formed on an exposed surface of the wiring at the bottom surface of the hole and on the underlayer deactivation layer at the side surface of the hole. The catalyst layer is formed on the underlayer at the bottom surface and the side surface of the hole. The carbon nanotube extends from the catalyst layer at the bottom surface of the hole, and fills the hole.