Organic light emitting display device and method of manufacturing the same

1. An organic light emitting display device comprising:

a substrate including a display area and a pad area;

a pad electrode structure on the substrate in the pad area and including a first pad electrode and a second pad electrode on the first pad electrode;

a protection conductive layer covering a lateral surface of the second pad electrode so as to reduce corrosion of the second pad electrode; and

a passivation layer covering an edge of the first pad electrode,

wherein the second pad electrode is electrically connected with the first pad electrode through a contact hole in the passivation layer.

2. The organic light emitting display device according to claim 1 , wherein the protection conductive layer is formed of one of transparent conductive oxide, molybdenum (Mo), and a molybdenum alloy (Mo alloy).

3. The organic light emitting display device according to claim 1 , further comprising:

a thin-film transistor on the substrate in the display area and including an active layer, a gate electrode, a source electrode, and a drain electrode; and

an anode electrically connected with the thin-film transistor and including a plurality of conductive layers,

wherein the first pad electrode is formed of same material as the source electrode and the drain electrode, and the second pad electrode is formed of a same material as the anode.

4. The organic light emitting display device according to claim 3 , wherein the anode has a structure in which a lower poly-ITO layer, a silver alloy layer, and an upper poly-ITO layer are laminated.

5. The organic light emitting display device according to claim 3 , wherein the source electrode and the drain electrode have a structure in which a copper (Cu) layer is laminated on a molybdenum-titanium (MoTi) alloy layer.

6. The organic light emitting display device according to claim 1 , wherein the protection conductive layer covers a lateral surface of the second pad electrode and at least a part of a top surface of the second pad electrode.

7. The organic light emitting display device according to claim 3 , further comprising:

a dummy layer covering the anode,

wherein the dummy layer is formed of a same material as the protection conductive layer.

8. An organic light emitting display device comprising:

a substrate including a display area and a pad area;

a thin film transistor on the substrate in the display area and including an active layer, agate electrode, a source electrode, and a drain electrode;

an anode electrically connected with the thin film transistor and including a plurality of conductive layers; and

a pad electrode structure on the substrate in the pad area and including a first pad electrode and a second pad electrode on the first pad electrode,

wherein a material of the second pad electrode is different in etching selectivity from a material of the anode, and

wherein the second pad electrode is formed of one of polymerized transparent conductive oxide, titanium (Ti), and a molybdenum-titanium (MoTi) alloy.

9. The organic light emitting display device according to claim 8 , wherein the material of the second pad electrode and the material of the anode are different from each other in etching selectivity with respect to an etchant for etching the material of the anode.

10. The organic light emitting display device according to claim 8 , wherein the second pad electrode is formed of a material which is not etched by an etchant for etching the anode.

11. The organic light emitting display device according to claim 8 , wherein each of the source electrode and the drain electrode includes a first conductive layer formed of a same material as the first pad electrode and a second conductive layer formed of a same material as the second pad electrode, and

the first conductive layer has a structure in which a copper (Cu) layer is laminated on a molybdenum-titanium (MoTi) alloy layer or a structure in which a molybdenum (Mo) layer, an aluminum (Al) layer, and a molybdenum layer are laminated.

12. The organic light emitting display device according to claim 8 , further comprising:

a passivation layer on the source electrode and the drain electrode and including a contact hole for revealing a part of a top surface of the second pad electrode; and

an external module in direct contact with the second pad electrode via the contact hole.

13. An organic light emitting display device comprising:

a substrate having a display area and a pad area;

a thin film transistor on the substrate in the display area and including an active layer, a gate electrode, a source electrode, and a drain electrode;

an anode electrically connected with the thin film transistor and including at least two layers;

a pad electrode structure on the substrate in the pad area and including a plurality of pad electrodes;

a planarization layer that covers the thin film transistor; and

a first auxiliary wiring on a top side of the planarization layer and on a same plane as the anode,

wherein a first pad electrode of the pad electrode structure is formed of a same material as the source electrode and the drain electrode, and a second pad electrode of the pad electrode structure and a third pad electrode of the pad electrode structure cover the first pad electrode, and

wherein the second pad electrode of the pad electrode structure and the third pad electrode of the pad electrode structure are formed of a same material as the first auxiliary wiring.

14. The organic light emitting display device according to claim 13 , wherein the anode has a structure in which a lower ITO (Indium Tin Oxide) layer, a silver alloy (Ag alloy) layer, and an upper ITO layer are laminated.

15. The organic light emitting display device according to claim 14 , wherein the anode further includes a dummy layer which is in contact with a rear side of the lower ITO layer and electrically connected with the lower ITO layer.

16. The organic light emitting display device according to claim 15 , wherein the dummy layer includes a plurality of layers, a lower layer of the plurality of layers has a structure in which a copper (Cu) layer is laminated on a molybdenum-titanium (MoTi) alloy layer, and an upper layer of the plurality of layers is formed of molybdenum-titanium (MoTi) alloy and covers the lower layer.

17. The organic light emitting display device according to claim 15 , wherein the dummy layer is formed of a same material as the second pad electrode of the pad electrode structure and the third pad electrode of the pad electrode structure.