The present application discloses a method for fabricating a semiconductor device using a tilted etch process. The method for fabricating the semiconductor device includes providing a target layer, forming a first hard mask layer on the target layer, forming second hard mask layers on the first hard mask layer, performing a first tilted etch process on the first hard mask layer to form first openings along the first hard mask layer and adjacent to first sides of the second hard mask layers, and performing a second tilted etch process on the first hard mask layer to form second openings along the first hard mask layer and adjacent to second sides of the second hard mask layers. The first tilted etch process and the second tilted etch process use the second hard mask layers as pattern guides and the first hard mask layer is turned into a patterned first hard mask layer by the first openings and the second openings.