A TFT array substrate includes: a gate electrode connected to a gate line; a source electrode connected to a data line crossing the gate line to define a pixel region; a drain electrode which is opposite to the source electrode with a channel in between; a semiconductor layer defining the channel between the source electrode and the drain electrode; a pixel electrode in the pixel region and connected to the drain electrode; a channel passivation layer on the channel of the semiconductor layer; a gate pad extending from the gate line, where a semiconductor pattern and a transparent conductive pattern are formed; a data pad connected to the data line, where the transparent conductive pattern is formed; and a gate insulating layer formed under the semiconductor layer, the gate line and the gate pad, and the data line and the data pad.