A method for fabricating a semiconductor device includes forming an etch target layer over a substrate that includes a cell region and a peripheral region. A first hard mask layer, a second hard mask layer, and an anti-reflective coating layer are formed over the etch target layer. A photosensitive pattern is formed over the anti-reflective coating layer. The anti-reflective coating layer is etched to have a width smaller than the width of the photosensitive pattern. The second hard mask layer is etched. A main etching and an over-etching are performed on the first hard mask layer. The etch target layer is then etched.