A semiconductor device includes a substrate having a first surface and a second surface opposite to each other, and having an active region located on the first surface and defined by a first isolation region; a plurality of active fins arranged on the active region, extending in a first direction, and defined by a second isolation region having a second depth smaller than a first depth of the first isolation region; a buried conductive wiring in a trench adjacent to the plurality of active fins, and extending in a direction of the trench; a filling insulation portion in the trench, and having the buried conductive wiring therein; an interlayer insulation layer on the first and second isolation regions and on the buried conductive wiring; a contact structure penetrating the interlayer insulation layer, and contacting the buried conductive wiring; and a conductive through structure extending through the substrate from the second surface to the trench, and contacting the buried conductive wiring.