A semiconductor device may include a plurality of conductive patterns and an insulation pattern. The plurality of conductive patterns may be formed on a substrate. The plurality of conductive patterns may be spaced apart from each other in a vertical direction perpendicular to an upper surface of the substrate. Each of the plurality of conductive patterns may have an extension portion and a step portion. The step portion may be disposed at an edge of the corresponding conductive pattern. The insulation pattern may be formed between the plurality of conductive patterns in the vertical direction. A lower surface and an upper surface of the step portion of each of the plurality of conductive patterns may be bent upwardly.