A method of manufacturing a display device, includes providing a substrate including a first stepped part, forming a metal layer on the substrate and the first stepped part, forming an organic layer pattern on the metal layer at a position corresponding to a sidewall of the stepped part, forming a photosensitive layer on the metal layer and the organic layer pattern, patterning the photosensitive layer to form a photosensitive layer pattern adjacent to the organic layer pattern, and forming a metal line by removing the organic layer pattern and an exposed portion of the metal layer through an etching process using the photosensitive layer pattern as a mask.