Etchant and array substrate having copper lines etched by the etchant

1. A method of using an etchant for simultaneously etching and patterning a double metal layer, comprising:

providing an etchant comprising: hydrogen peroxide (H 2 O 2 ); sulfuric acid; a neutral salt; and a hydrogen peroxide (H 2 O 2 ) stabilizer;

controlling the concentration of hydrogen peroxide in the etchant at a value such that the etchant simultaneously etches and patterns both layers of the double metal layer;

controlling a molar ratio of hydrogen peroxide to sulfuric acid in the etchant to determine an etch time of the double metal layer; and

simultaneously etching and patterning both layers of the double metal layer using the etchant.

2. A method of using an etchant for simultaneously etching and patterning a double metal layer that includes a copper (Cu) layer and a molybdenum (Mo) layer, comprising:

providing an etchant comprising: hydrogen peroxide (H 2 O 2 ); at least one of an organic acid, and an inorganic acid, and a neutral salt; and a hydrogen peroxide (H 2 O 2 ) stabilizer;

controlling the concentration of hydrogen peroxide in the etchant at a value such that the etchant simultaneously etches and patterns both the Cu layer and the Mo layer of the double metal layer; and

simultaneously etching and patterning both the Cu layer and the Mo layer of the double metal layer.

3. The method of claim 2 , wherein the at least one of an organic acid, and an inorganic acid, and a neutral salt includes acetic acid.

4. The method of claim 2 , wherein the at least one of an organic acid, and an inorganic acid, and a neutral salt includes nitric acid.

5. The method of claim 2 wherein the at least one of an organic acid, and an inorganic acid, and a neutral salt includes hydrochloric acid.

6. The method of claim 2 , wherein the at least one of an organic acid, and an inorganic acid, and a neutral salt includes phosphoric acid.

7. The method of claim 2 , wherein the at least one of an organic acid, and an inorganic acid, and a neutral salt includes one of potassium chloride, sodium chloride, potassium hydrogen sulfate and potassium metaperiodate.

8. The method of claim 7 wherein the one of potassium chloride, sodium chloride, potassium hydrogen sulfate and potassium metaperiodate includes potassium hydrogen sulfate.

9. A method of using an etchant for simultaneously etching and patterning a double metal layer that includes a copper (Cu) layer and a molybdenum (Mo) layer, comprising:

providing an etchant comprising: hydrogen peroxide (H 2 O 2 ); sulfuric acid (H 2 SO 4 ); and a hydrogen peroxide (H 2 O 2 ) stablizer;

controlling a molar ratio of hydrogen peroxide to sulfuric acid in the etchant to determine an etch time of the copper layer;

controlling a concentration of hydrogen peroxide in the etchant at a value such that the etchant simultaneously etches and patterns both the Cu layer and the Mo layer of the double metal layer; and

simultaneously etching and patterning both the Cu layer and the Mo layer of the double metal layer.

10. The method of claim 9 , wherein the molar ratio of hydrogen peroxide to sulfuric acid is controlled such that 1000 angstroms of copper is etched in between about 5 and about 15 seconds.

11. The method of claim 9 , wherein the concentration of hydrogen peroxide is controlled such that an etch rate of molybdenum is between about 500 and about 2000 angstroms per minute.

12. A method of fabricating a thin film transistor of display device, comprising:

forming a first metal layer on a substrate;

forming a second metal layer on the first metal layer;

patterning the first metal layer and the second metal layer to form a gate line and a gate electrode using an etchant that includes hydrogen peroxide (H 2 O 2 ) and a hydrogen peroxide (H 2 O 2 ) stabilizer and

forming a gate insulation layer on the gate line and the gate electrode;

forming an active layer on the gate insulation layer;

forming an ohmic contact layer on the active layer;

forming a third metal layer on the active layer;

forming a passivation layer on the second metal layer; and

forming a pixel electrode on the passivation layer; forming a fourth metal layer on the third metal layer;

patterning the third metal layer and the fourth metal layer to form a data line, a source electrode and a drain electrode using an etchant that includes hydrogen peroxide (H 2 O 2 ) and a hydrogen peroxide (H 2 O 2 ) stabilizer.

13. The method of claim 12 , wherein the first metal layer includes a molybdenum (Mo) layer.

14. The method of claim 12 , wherein the second metal layer includes a copper (Cu) layer.

15. The method of claim 12 , wherein the pixel electrode is electrically connected to the third metal layer.

16. The method of claim 12 , wherein the third metal layer includes a molybdenum (Mo) layer.

17. The method of claim 12 , wherein the fourth metal layer includes a copper (Cu) layer.

18. A method of fabricating a thin film transistor of a display device, comprising:

forming a first metal layer on a substrate;

forming a second metal layer including a copper (Cu) layer or copper alloy layer on the first metal layer; and

patterning the first and second metal layers using an etchant, the etchant including hydrogen peroxide (H 2 O 2 ) and at least one of an organic acid and a neutral salt;

forming a pixel region with the first metal layer and the second metal layer, the pixel region having a thin film transistor;

controlling the concentration of hydrogen peroxide in the etchant at a value such that the etchant simultaneously etches and patterns both the first metal layer and the second metal layer; and

simultaneously etching and patterning both the first metal layer and the second metal layer of the double metal layer.

19. The method of claim 18 , wherein the second metal layer includes a molybdenum (Mo) layer.

20. The method of claim 18 , wherein the first and second metal layers include a gate line and a gate electrode.

21. The method of claim 18 , wherein the first and second metal layers include a data line and source and drain electrodes.

22. The method of claim 18 , further comprising forming a pixel electrode on the second metal layer.

23. The method of claim 18 , wherein the etchant further comprises a hydrogen peroxide (H 2 O 2 ) stabilizer.

24. The method of claim 18 , wherein the organic acid includes an acetic acid (CH 3 COOH).

25. The method of claim 18 , wherein the neutral salt includes one of potassium chloride (KCl), sodium chloride (NaCl), potassium hydrogen sulfate (KHSO 4 ), and potassium metaperiodate (KIO4).

26. The method of claim 18 , wherein the etchant further comprises an inorganic acid.

27. The method of claim 26 , wherein the inorganic acid includes one of sulfuric acid (H 2 SO 4 ), nitric acid (HNO 3 ), hydrochloric acid (HCl), and phosphoric acid (H 3 PO 4 ).

28. The method of claim 18 , further comprising forming an insulation layer on the second metal layer.

29. The method of claim 28 , wherein the insulation layer is formed of one of an inorganic material and an organic material.

30. The method of claim 29 , wherein the inorganic material includes one of silicon oxide (SiOx) and silicon nitride (SiNx).

31. The method of claim 29 , wherein the organic material includes one of benzocyclobutene (BCB) and an acryl-base resin.