1. A method for manufacturing a semiconductor device, the method comprising: obtaining a design layout for a target layer of an optical proximity correction process, the design layout including a first block and a second block being a repetition block of the first block; dividing the design layout into a plurality of patches; performing the optical proximity correction process on the patches of the first block; applying corrected patches of the first block to the patches of the second block, respectively; forming a correction layout by performing the optical proximity correction process on boundary patches of the second block; fabricating a photomask corresponding to the correction layout; and forming patterns on a substrate corresponding to the photomask, wherein each of the patches is a standard unit on which the optical proximity correction process is performed.