Etching solution for etching Cu and Cu/Ti metal layer of liquid crystal display device and method of fabricating the same
View Patent ↗An etching solution for etching one of a copper single metal layer and a copper (Cu)/titanium (Ti) double metal layer that serves as one of a gate electrode, a source electrode, and a drain electrode of a thin film transistor for a liquid crystal display (LCD) device includes oxone, fluoric compounds, one of a reducing agent and a weak oxidizing agent, an etching rate restrainer, KHF 2 , and water.
1. An etching solution for etching one of a copper single metal layer and a copper (Cu)/titanium (Ti) double metal layer that serves as one of a gate electrode, a source electrode, and a drain electrode of a thin film transistor for a liquid crystal display (LCD) device, comprising:
oxone;
fluoric compounds;
one of a reducing agent and a weak oxidizing agent;
an etching rate restrainer;
KHF 2 ; and
water.
2. The etching solution according to claim 1 , wherein a concentration of the oxone is between 3 and 5 wt %.
3. The etching solution according to claim 1 , wherein the fluoric compounds include hydrofluoric acid (HF) and ammonium fluoride (NH 4 F).
4. The etching solution according to claim 3 , wherein a concentration of the hydrofluoric acid (HF) is between 0.1 and 0.3 wt % and a concentration of the ammonium fluoride (NH 4 F) is between 0 and 0.1 wt %.
5. The etching solution according to claim 1 , wherein the weak oxidizing agent includes (NH 4 ) 2 S 2 O 8 .
6. The etching solution according to claim 5 , wherein a concentration of the weak oxidizing agent is between 0.1 and 1 wt %.
7. The etching solution according to claim 1 , wherein the reducing agent includes one of Na 2 SO 3 , K 2 SO 3 and (NH 4 )SO 3 .
8. The etching solution according to claim 7 , wherein a concentration of the reducing agent is between 0.1 and 1 wt %.
9. The etching solution according to claim 1 , wherein the etching rate restrainer includes a salicylic acid derivative.
10. The etching solution according to claim 9 , wherein a concentration of the salicylic acid derivative is between 0.01 and 0.2 wt %.
11. A method for fabricating a thin film transistor for a liquid crystal display device, comprising steps of:
forming gate, source, and drain electrodes of one of a copper single metal layer and a copper/titanium double metal layer on a substrate; and
etching the one of a copper single metal layer and a copper/titanium double metal layer using an etching solution including oxone, fluoric compounds, one of a reducing agent and a weak oxidizing agent, an etching rate restrainer, KHF 2 , and water.
12. The method according to claim 11 , wherein a concentration of the oxone is between 3 and 5 wt %.
13. The method according to claim 11 , wherein the fluoric compounds include hydrofluoric acid (HF) and ammonium fluoride (NH 4 F).
14. The method according to claim 13 , wherein a concentration of the hydrofluoric acid (HF) is between 0.1 and 0.3 wt % and a concentration of the ammonium fluoride (NH 4 F) is between 0 and 0.1 wt %.
15. The method according to claim 11 , wherein the weak oxidizing agent includes (NH 4 ) 2 S 2 O 8 .
16. The method according to claim 15 , wherein a concentration of the weak oxidizing agent is between 0.1 and 1 wt %.
17. The method according to claim 11 , wherein the reducing agent includes one of Na 2 SO 3 , K 2 SO 3 and (NH 4 )SO 3 .
18. The method according to claim 17 , wherein a concentration of the reducing agent is between 0.1 and 1 wt %.
19. The method according to claim 1 , wherein the etching rate restrainer includes a salicylic acid derivative.
20. The method according to claim 19 , wherein a concentration of the salicylic acid derivative is between 0.01 and 0.2 wt %.