A method of manufacturing a display device including providing a substrate, forming a semiconductor layer on the substrate, forming a first insulating layer on the semiconductor layer, forming a metal layer on the first insulating layer, forming a second insulating layer on the metal layer, forming an etching buffer layer on the second insulating layer, forming a photosensitive film pattern on the etching buffer layer, and etching the etching buffer layer and the first and second insulating layers to expose the semiconductor layer.