Semiconductor Device and Manufacturing Method Thereof

A manufacturing method of a semiconductor device having a stacked structure in which a lower layer is exposed is provided without increasing the number of masks. A source electrode layer and a drain electrode layer are formed by forming a conductive film to have a two-layer structure, forming an etching mask thereover, etching the conductive film using the etching mask, and performing side-etching on an upper layer of the conductive film in a state where the etching mask is left so that part of a lower layer is exposed. The thus formed source and drain electrode layers and a pixel electrode layer are connected in a portion of the exposed lower layer. In the conductive film, the lower layer and the upper layer may be a Ti layer and an Al layer, respectively. The plurality of openings may be provided in the etching mask.