A semiconductor device includes a second insulating layer disposed on a substrate and that includes a first trench that extends in a first direction, a first via disposed in the first hole, a first interconnection layer disposed in the first trench on the first via and that has an upwardly upper region, and a third insulating layer disposed on the second insulating layer and that includes a second hole and a second trench connected to the second hole. The first trench has inclined side surfaces such that a width of the first trench increases in a direction toward the substrate, the second hole has inclined side surfaces such that a width of the second hole decreases in the direction toward the substrate, and a lower portion of the second hole is wider than an upper surface of the first interconnection layer.