Patent ID: 8298839

Claim:
A method of producing a thin film active element, comprising the steps of: forming a light-shielding conductive layer on a light-permeable substrate; forming a light-permeable conductive layer in a region adjacent to the light-shielding conductive layer so as to overlap at least a side of a part in the light-shielding conductive layer; forming a photoresist film covering the light-permeable conductive layer; exposing the photoresist film using the light-shielding conductive layer as a light-shielding mask from a direction of the substrate; forming a mask pattern by developing the photoresist film such that the region of the exposed photoresist film remains; performing etching until the light-shielding conductive layer and the light-permeable conductive layer are spaced apart from each other by overetching the light-permeable conductive layer using the mask pattern as a mask until an etching species comes under the mask; and forming a channel layer functioning as a carrier region of the active element in a gap between the light-permeable conductive layer and light-shielding conductive layer which are spaced apart from each other.