Thin film transistor substrate having metal oxide semiconductor and manufacturing the same

A method for manufacturing a thin film transistor substrate, the method comprising:

• a first mask process for forming a gate element with a gate metal material on a substrate;
• a second mask process for forming a thin film transistor, a pixel electrode and a data element by sequentially depositing a gate insulating layer, an oxide semiconductor material, an etch stopper material and a data metal material on the gate element and patterning;
• a third mask process for exposing some portions of a source area of the thin film transistor and the data element by depositing a passivation layer on the substrate having the data element and patterning;
• and
• a fourth mask process for forming a source electrode connecting the source area to the data element and a common electrode overlapping with the pixel electrode having the passivation layer there-between by depositing a transparent conductive material on the passivation layer and patterning,
• wherein the second mask process further includes:
• forming an etch stopper overlapping with a middle portion of a gate electrode of the gate element, a data line crossing a gate line of the gate element, and a semiconductor layer expanding from under the data line through under the etch stopper to a pixel area by patterning the oxide semiconductor material, the etch stopper material and the data metal material with a half-tone mask;
• and
• forming the source area and a drain area of the thin film transistor, and the pixel electrode by selective plasma treatment of the oxide semiconductor material extended from a channel layer of the thin film transistor using the data element and the etch stopper as a mask.