Thin film transistor array substrate, method of manufacturing the same, and display device

The present invention provides a thin film transistor array, capable of easily controlling channel length of TFT without adding optical etching step, and manufacturing method and display. The thin film transistor array substrate includes a gate electrode formed on a substrate, a gate insulating film formed over the gate electrode, a source electrode and a drain electrode that are formed on the gate insulating film and include a transparent conductive film and a metal film formed on the transparent conductive film, a semiconductor film formed over the source electrode and the drain electrode to be electrically connected to the source electrode and the drain electrode, and a pixel electrode formed extending from the drain electrode.