Thin film transistor and manufacturing method thereof, and display device and manufacturing method thereof

摘要

To provide a manufacturing method of a thin film transistor and a display device with fewer masks than a conventional method. A thin film transistor is manufactured by including the steps of: forming a first conductive film, an insulating film, a semiconductor film, an impurity semiconductor film, and a second conductive film to be stacked; forming a resist mask including three regions with different thicknesses; performing first etching to form a thin-film stack body; performing second etching in which side-etching is performed on the thin-film stack body to form a gate electrode layer; and recessing the resist mask to form a semiconductor layer and a source and drain electrode layer. A resist mask including three regions with different thicknesses can be formed using a four-tone photomask, for example.