Patent ID: 8679904

Claim:
A method for manufacturing a display device, the display device including: a thin film transistor including: a substrate; a gate electrode provided on the substrate; a gate insulating film provided on the gate electrode; a semiconductor layer provided on the gate insulating film, the semiconductor layer being formed of oxide; a source electrode and a drain electrode provided on the semiconductor layer, the source electrode being opposed to one end of the gate electrode, the drain electrode being opposed to another end of the gate electrode, the another end being opposite to the one end, the drain electrode being apart from the source electrode; and a channel protecting layer including a first portion provided between the source electrode and the semiconductor layer, and a second portion provided between the drain electrode and the semiconductor layer; a pixel electrode connected to one of the source electrode and the drain electrode; and an optical element producing at least one of a change in optical characteristics and light emission by an electric signal provided to the pixel electrode, the method comprising: forming the gate electrode on the substrate; forming the gate insulating film on the gate electrode; forming the semiconductor layer as a layer of the oxide on the gate insulating film; forming the channel protecting layer covering the layer of the oxide and exposing the layer of the oxide in a first region, the pixel electrode being formed in the first region; performing a heat treatment on the layer of the oxide with the channel protecting layer covering a top and sides of the semiconductor layer at a temperature not less than 160° C.; forming the source electrode and the drain electrode on the semiconductor layer and the channel protecting layer after the performing the heat treatment; and performing a surface processing selectively changing smoothness of a surface of the gate insulating film before the forming the semiconductor layer as the layer of the oxide, wherein the performing the surface processing includes making the surface of the gate insulating film in the first region rougher than the surface of the gate insulating film in a region except the first region.