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

1. An organic light-emitting display device, comprising:

a substrate in which a light-emitting region and a thin-film transistor (TFT) region are defined; and

a plurality of insulating films formed on the substrate,

wherein a refractive index changes at only one of interfaces between insulating films, which correspond to the light-emitting region and which are formed between the substrate and a first electrode of an organic electroluminescence display element, and a refractive index changes at at least two interfaces between insulating films which correspond to the TFT region.

2. The display device of claim 1 , wherein the TFT region of the substrate comprises:

a first insulating film formed on the substrate;

a semiconductor layer formed on the first insulating film;

a second insulating film formed on the semiconductor layer;

a gate electrode formed on the second insulating film;

a third insulating film formed on the gate electrode;

source and drain electrodes formed on the third insulating film; and

a fourth insulating film formed on the source and drain electrodes.

3. The display device of claim 2 , wherein the first insulating film comprises a first sub-insulating film and a second sub-insulating film formed sequentially on the substrate, wherein the first sub-insulating film is made of one of SiN x and SiON, and the second sub-insulating film is made of SiO 2 .

4. The display device of claim 3 , wherein the second insulating film comprises a third sub-insulating film and a fourth sub-insulating film formed sequentially on the semiconductor layer, wherein the third sub-insulating film is made of SiO 2 , and the fourth sub-insulating film is made of one of SiN x , SiON, and a high-k film.

5. The display device of claim 4 , wherein the third insulating film comprises a fifth sub-insulating film and a sixth sub-insulating film formed sequentially on the gate electrode, wherein the fifth sub-insulating film is made of SiO 2 , and the sixth sub-insulating film is made of one of SiN x and SiON.

6. The display device of claim 5 , wherein the third sub-insulating film directly contacts the substrate in the light-emitting region.

7. The display device of claim 6 , wherein the fifth sub-insulating film directly contacts the third sub-insulating film in the light-emitting region.

8. The display device of claim 7 , wherein the refractive index changes only at an interface between the fifth sub-insulating film and the sixth sub-insulating film disposed between the substrate and the first electrode of the organic electroluminescence display element in the light-emitting region.

9. The display device of claim 4 , wherein the fourth sub-insulating film has a same pattern shape as the gate electrode.

10. The display device of claim 4 , wherein the substrate further comprises a capacitor region, and wherein the capacitor region comprises:

the first and second sub-insulating films formed on the substrate;

a capacitor first electrode formed on the second sub-insulating film;

the third and fourth sub-insulating films formed on the capacitor first electrode; and

a capacitor second electrode formed on the fourth sub-insulating film.

11. The display device of claim 3 , wherein the first sub-insulating film and the second sub-insulating film have a same pattern shape as the semiconductor layer.

12. The display device of claim 3 , wherein the first and second sub-insulating films comprise regions which protrude from sidewalls of the semiconductor layer.

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

sequentially forming a first insulating film, which comprises a stack of a first sub-insulating film and a second sub-insulating film, and a film for forming a semiconductor layer on a substrate in which a light-emitting region and a TFT region are defined;

forming a first photoresist pattern on the film for forming the semiconductor layer;

etching the film for forming the semiconductor layer, the second sub-insulating film, and the first sub-insulating film using the first photoresist pattern as an etch mask;

removing the first photoresist pattern and then sequentially forming a second insulating film, which comprises a stack of a third sub-insulating film and a fourth sub-insulating film, and a conductive film for forming a gate electrode on an entire surface of the substrate having a semiconductor layer;

forming a second photoresist pattern on the conductive film for forming the gate electrode; and

etching the conductive film for forming the gate electrode and the fourth sub-insulating film using the second photoresist pattern as an etch mask.

14. The method of claim 13 , wherein the first sub-insulating film is made of one of SiN x and SiON, the second and third sub-insulating films are made of SiO 2 , and the fourth sub-insulating film is made of one of SiN x , SiON, and a high-k film.

15. The method of claim 14 , wherein the first photoresist pattern comprises a first region and a second region having different thicknesses, wherein the first region is thicker than the second region, the first region corresponds to a region in which the semiconductor layer is formed, and the second region corresponds to the TFT region excluding the light-emitting region.

16. The method of claim 14 , further comprising:

removing the second photoresist pattern and then forming a third insulating film, which comprises a stack of a fifth sub-insulating film and a sixth sub-insulating film, on the entire surface of the substrate having a gate electrode;

forming source and drain electrodes on the sixth sub-insulating film; and

forming a fourth insulating film on the entire surface of the substrate having the source and drain electrodes.

17. The method of claim 16 , wherein the fifth sub-insulating film is made of SiO 2 , and the sixth sub-insulating film and the fourth insulating film are made of one of SiN x and SiON.

18. An organic light-emitting display device fabricated by the method of claim 16 , wherein a refractive index changes at only one of interfaces between insulating films, which correspond to the light-emitting region and which are formed between the substrate and a first electrode of an organic electroluminescence display element, and a refractive index changes at at least two interfaces between insulating films which correspond to the TFT region.

19. An organic light-emitting display device fabricated by the method of claim 16 , wherein the TFT region of the substrate comprises:

the first insulating film formed on the substrate;

the semiconductor layer formed on the first insulating film;

the second insulating film formed on the semiconductor layer;

the gate electrode formed on the second insulating film;

a third insulating film formed on the gate electrode;

source and drain electrodes formed on the third insulating film; and

a fourth insulating film formed on the source and drain electrodes.

20. The method of claim 15 , wherein the first photoresist pattern is formed using a slit mask or a halftone mask.