Method of manufacturing thin film transistor substrate

1. A method of manufacturing a thin film transistor (TFT) substrate, the method comprising:

forming a gate wire on an insulating substrate, the gate wire comprising a gate line extending in a first direction and a gate electrode connected to the gate line;

forming a data wire on the insulating substrate, the data wire insulated from the gate wire and comprising a data line extending in a second direction to intersect the gate line having a pixel disposed at the intersection, a source electrode connected to the data line, and a drain electrode separated from the source electrode; and

forming a pixel electrode connected to the drain electrode at each pixel,

wherein forming the gate wire or the data wire includes forming a barrier layer on a lower structure, forming a copper conductive layer comprising copper or copper alloy on the barrier layer, forming an intermediate layer comprising copper nitride on the copper conductive layer, forming a capping layer comprising Mo, MoN, MoW, MoTi, MoNb, MoZr, IZO, ITO, amorphous ITO, or a compound thereof on the intermediate layer, etching the capping layer, the intermediate layer, and the copper conductive layer to expose the barrier layer, and etching the barrier layer,

wherein an upper surface of the intermediate layer of the drain electrode is fully covered by the capping layer.

2. The method of claim 1 , wherein the barrier layer comprises Cr, Ti, Ta, V, Zr, W, Nb, Co, Ni, Pd, Pt, or a compound thereof.

3. The method of claim 1 , wherein in forming the intermediate layer, a copper target is sputtered under a nitrogen-containing atmosphere.

4. The method of claim 3 , wherein forming the copper conductive layer and forming the intermediate layer are continuously performed in situ while supplying nitrogen.

5. The method of claim 1 , wherein the intermediate layer has a thickness in a range of about 50 to about 1,000 angstroms.

6. The method of claim 1 , wherein the intermediate layer comprises about 0.001 to about 50 atomic percent of nitrogen.

7. The method of claim 1 , wherein in etching the capping layer, the intermediate layer, and the copper conductive layer, the capping layer, the intermediate layer, and the copper conductive layer are wet-etched.

8. The method of claim 7 , wherein in etching the capping layer, the intermediate layer, and the copper conductive layer, the capping layer, the intermediate layer, and the copper conductive layer are etched in the same process using the same etchant.

9. The method of claim 1 , wherein in etching the barrier layer, the barrier layer is dry-etched.

10. The method of claim 1 , wherein etching the barrier layer for the forming of the data wire further comprises etching an ohmic contact layer under the barrier layer to expose a semiconductor layer.

11. The method of claim 10 , wherein etching the barrier layer for the forming of the data wire and etching the ohmic contact layer are continuously performed.