Manufacturing method of display device, display device, display module, and electronic device

Abstract

A display device with high display quality is provided. A first film is formed over a first pixel electrode; a first mask film is formed over the first film and a first conductive layer; the first film and the first mask film are processed to form a first layer and a first mask layer over the first pixel electrode and a second mask layer over the first conductive layer; a first insulating film is formed over the first mask layer and the second mask layer; a second insulating film is formed over the first insulating film with use of a photosensitive resin composite; a portion of the second insulating film that overlaps with the second mask layer is removed and a portion of the second insulating film that overlaps with the first mask layer is further removed; after performing heat treatment, part of the first mask layer is removed to expose a top surface of the first layer; and a common electrode is formed to cover the first layer, the first conductive layer, and the second insulating layer.