Organic light-emitting display device and method of manufacturing the same

1. A method of manufacturing an organic light-emitting display device, the method comprising:

forming a semiconductor active layer on a substrate;

forming a gate insulating layer on the substrate and the semiconductor active layer;

forming a gate electrode comprising a lower gate electrode on the gate insulating layer and an upper gate electrode on the lower gate electrode;

forming a source region and a drain region at the semiconductor active layer using the gate electrode as a mask;

forming an interlayer insulating layer on the substrate and etching the interlayer insulating layer, resulting in contact holes that expose portions of the source region and the drain region;

forming a source/drain electrode raw material on the substrate and etching the source/drain electrode raw material to form a source electrode and a drain electrode;

after forming the source electrode and drain electrode, forming a gate-overlapped lightly doped drain (GOLDD) structure having a lightly doped drain (LDD) region at the semiconductor active layer by injecting impurity ions;

depositing a protective layer on the substrate; and

forming a display device on the substrate.

2. The method of claim 1 , wherein when the interlayer insulating layer is etched, edge portions of the upper gate electrode are exposed.

3. The method of claim 2 , wherein when the source/drain electrode raw material is etched, the edge portions of the upper gate electrode are etched concurrently with the source/drain electrode raw material to expose edge portions of the lower gate electrode.

4. The method of claim 3 , wherein the length of the upper gate electrode is shorter than that of the lower gate electrode.

5. The method of claim 3 , wherein after the source/drain electrode raw material is etched,

the source electrode is electrically connected to the source region, and

the drain electrode is electrically connected to the drain region,

wherein the source electrode and the drain electrode surround side walls of the gate insulating layer and the interlayer insulating layer, and portions of the contact holes remain empty.

6. The method of claim 3 , wherein the forming of the GOLDD structure comprises injecting impurity ions via the edge portions of the lower gate electrode such that the LDD region having low impurity ion concentration is formed at a portion of the semiconductor active layer vertically corresponding to the edge portions of the lower gate electrode.

7. The method of claim 6 , wherein the edge portions of the lower gate electrode and the LDD region having low impurity ion concentration overlap each other.

8. The method of claim 1 , wherein the lower gate electrode comprises a transparent conductive film.

9. The method of claim 1 , wherein the upper gate electrode has a single-layered structure comprising one selected from the group consisting of Mo, MoW, Cr, Al, an Al alloy, Mg, Al, Ni, W, and Au, or a multi-layered structure comprising a mixture of Mo, MoW, Cr, Al, an Al alloy, Mg, Al, Ni, W, and Au.

10. The method of claim 1 , further comprising forming a protective layer in the contact holes.

11. The method of claim 1 , wherein the display device is an organic light-emitting device.

12. The method of claim 1 , wherein when the source/drain electrode raw material is etched to form the source electrode and the drain electrode, portions of the source electrode and the drain electrode are left exposed.