A semiconductor device can include an insulation layer on that is on a substrate on which a plurality of lower conductive structures are formed, where the insulation layer has an opening. A barrier layer is on a sidewall and a bottom of the opening of the insulation layer, where the barrier layer includes a first barrier layer in which a constituent of a first deoxidizing material is richer than a metal material in the first barrier layer and a second barrier layer in which a metal material in the second barrier layer is richer than a constituent of a second deoxidizing material. An interconnection is in the opening of which the sidewall and the bottom are covered with the barrier layer, the interconnection is electrically connected to the lower conductive structure.