A semiconductor device and a fabricating method thereof are provided. The method includes sequentially forming an interlayer insulating layer and a hard mask layer on a substrate with first and second regions, performing a first patterning process on the hard mask layer to form first openings in the first and second regions, performing a second patterning process on the hard mask layer to form second openings in the first and second regions, and performing a third patterning process on the hard mask layer to selectively form at least one third opening in only the second region. The third patterning process includes forming a first photoresist pattern with openings on the hard mask layer, and the opening of the first photoresist pattern on the first region is overlapped with the second opening on the first region, when viewed in a plan view.