Display device

1. A display device comprising:

a substrate including a display area and a pad area;

a data conductive layer disposed on the substrate;

a passivation layer disposed on the data conductive layer;

a via layer disposed on the passivation layer; and

a pixel electrode disposed on the via layer, wherein

the data conductive layer includes:

a data base layer;

a data main metal layer disposed on the data base layer;

a first data capping layer disposed on the data main metal layer;

a second data capping layer disposed on the first data capping layer; and

a third data capping layer disposed on the second data capping layer,

the passivation layer and the via layer include a pad opening which exposes a portion of the data conductive layer in the pad area,

the third data capping layer has a higher etch rate than the first and second data capping layers for a same etchant in a mask process in which the first, second, and third data capping layers are formed, and

the third data capping layer includes a pad conductive layer which exposes the second data capping layer through the pad opening.

2. The display device of claim 1 , wherein the third data capping layer has a twice higher etch rate than the first and second data capping layers for the same etchant in the mask process.

3. The display device of claim 2 , wherein the third data capping layer includes copper (Cu) or zinc indium oxide (ZIO).

4. The display device of claim 3 , wherein the data main metal layer and the third data capping layer include copper.

5. The display device of claim 3 , wherein the third data capping layer has a thickness in a range of about 10 Å to about 100 Å.

6. The display device of claim 3 , wherein the data base layer and the first data capping layer include a same material and include at least one of titanium (Ti), tantalum (Ta), calcium (Ca), chromium (Cr), magnesium (Mg), and nickel (Ni).

7. The display device of claim 6 , wherein the data base layer and the first data capping layer include titanium.

8. The display device of claim 3 , wherein the second data capping layer includes indium tin oxide (ITO).

9. The display device of claim 1 , wherein side surfaces of each layer of the data conductive layer are aligned with each other.

10. The display device of claim 1 , wherein side surfaces of the passivation layer are aligned with corresponding side surfaces of the pad conductive layer.

11. The display device of claim 1 , wherein

the passivation layer overlaps the pad conductive layer, and

side surfaces of the passivation layer protrude outwardly beyond side surfaces of the pad conductive layer.

12. A display device comprising:

a substrate including a display area and a pad area;

a data conductive layer disposed on the substrate;

a passivation layer disposed on the data conductive layer;

a via layer disposed on the passivation layer; and

a pixel electrode disposed on the via layer, wherein

the data conductive layer includes:

a data base layer;

a data main metal layer disposed on the data base layer;

a first data capping layer disposed on the data main metal layer;

a second data capping layer disposed on the first data capping layer; and

a third data capping layer disposed on the second data capping layer,

the passivation layer and the via layer include:

a first contact hole which penetrates the passivation layer and the via layer in a thickness direction to expose a portion of the data conductive layer in the display area; and

a pad opening which exposes a portion of the data conductive layer in the pad area,

the data conductive layer includes:

a first area which overlaps the passivation layer;

a second area which overlaps the first contact hole; and

a third area which overlaps the pad opening,

the third data capping layer is disposed in the entire first and second areas of the data conductive layer, and

the third data capping layer includes a pad conductive layer which does not overlap the pad opening in the third area of the data conductive layer.

13. The display device of claim 12 , wherein the third data capping layer contacts the pixel electrode in the second area of the data conductive layer.

14. The display device of claim 12 , further comprising:

a lower metal layer disposed on the substrate below the first area of the data conductive layer; and

at least one insulating layer disposed between the data conductive layer and the lower metal layer.

15. The display device of claim 14 , wherein

the at least one insulating layer includes a contact hole which penetrates the at least one insulating layer in the thickness direction to expose the lower metal layer, and

the lower metal layer is electrically connected to the data conductive layer through the contact hole.

16. The display device of claim 12 , wherein portions of the third data capping layer in the first and second areas of the data conductive layer and the pad conductive layer in the third area of the data conductive layer include a same material.

17. The display device of claim 12 , wherein the third data capping layer has a higher etch rate than the first and second data capping layers for a same etchant in a mask process in which the first, second, and third data capping layers are formed.

18. The display device of claim 17 , wherein the third data capping layer includes copper (Cu) or zinc indium oxide (ZIO).

19. The display device of claim 18 , wherein the data main metal layer and the third data capping layer include copper.

20. The display device of claim 18 , wherein the third data capping layer has a thickness in a range of about 10 Å to about 100 Å.