Exposure mask and method of manufacturing display device using the same

A method of manufacturing a display device, the method comprising:

• forming at least one reference pattern on a substrate including a first shot area and a second shot area adjacent to the first shot area;
• forming a first material layer on the at least one reference pattern;
• forming a first photoresist layer on the first material layer;
• matching an exposure mask on the first shot area of the substrate and exposing the first photoresist layer using the exposure mask;
• matching the exposure mask on the second shot area of the substrate and exposing the first photoresist layer using the exposure mask;
• developing the first photoresist layer to form a first inspection resist pattern arranged in a polygonal or a circular shape in which a portion of an outer shape is recessed inward in plan view, and exposing a portion of the first material layer;
• determining whether the exposure mask has an alignment error from the first inspection resist pattern;
• and
• forming a first contact hole in the first material layer using the first photoresist layer as a mask and removing the first photoresist layer to form a first insulating layer in which the first contact hole is defined in case that it is determined that there is no alignment error of the exposure mask.