A first resist pattern is formed by exposure using a first multi-tone photomask, and a first conductive layer, a first insulating layer, a first semiconductor layer, and a second semiconductor layer are etched, so that an island-shaped single layer and an island-shaped stack are formed. Here, sidewalls are formed on side surfaces of the island-shaped single layer and the island-shaped stack. Further, a second resist pattern is formed by exposure using a second multi-tone photomask, and a second conductive layer and the second semiconductor layer are etched, so that a thin film transistor, a pixel electrode, and a connection terminal are formed. After that, a third resist pattern is formed by exposure from a rear side using metal layers of the first conductive layer and the second conductive layer as masks, and the third insulating layer are etched, so that a protective insulating layer is formed.