Method of manufacturing display panel substrate

A method of manufacturing a display panel substrate having a semiconductor element, the method comprising:

• a film forming step of forming a thin film on a substrate;
• a resist film forming step, after the film forming step, of forming a positive resist film on the thin film;
• a first exposure step, after the resist film forming step, of selectively exposing a part of the resist film via a photomask including a pattern corresponding to at least a pattern of the semiconductor element;
• a second exposure step, after the first exposure step, of selectively exposing a part of the resist film by scanning and irradiating the resist film with light along an outline shape of the display panel substrate;
• a developing step, after the second exposure step, of developing the resist film so as to form a resist pattern on the thin film by removing a part of the resist film that is exposed in the first exposure step and the second exposure step;
• an etching step, after the developing step, of etching the thin film using the resist pattern as a mask, so as to selectively remove a part of the thin film and form a thin-film pattern;
• and
• a peeling step, after the etching step, of peeling the resist pattern from the thin-film pattern.