Liquid crystal display device and fabricating method thereof

• US 20060119771A1
• Filed: 06/29/2005
• Published: 06/08/2006
• Est. Priority Date: 12/04/2004
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Lim, Joo Soo, Kim, Woong Sik
• Granted Patent: US 7,626,669 B2
• Time in Patent Office: Days
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/13458 Terminal pads
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer

Abstract

The present invention relates to a transflective thin film transistor substrate and method of fabricating the same that is adaptive for simplifying its process. The liquid crystal display device includes: first and second substrates; a gate line on the first substrate; a gate insulating film on the first substrate; a data line crossing the gate line to define a pixel area; a thin film transistor connected to the gate line and the data line; an organic insulating film on the gate line, the data line and the thin film transistor, and having a transmission hole in the pixel area; a pixel electrode on the organic insulating film of the pixel area via the transmission hole and connected to the thin film transistor; and a reflective electrode on the pixel electrode having a same edge part as the pixel electrode or an edge part located at inner side from an edge part of the pixel electrode and exposing the pixel electrode of the transmission hole.

Claims

1. A liquid crystal display device, comprising:

first and second substrates;

a gate line on the first substrate;

a gate insulating film on the first substrate;

a data line crossing the gate line to define a pixel area;

a thin film transistor connected to the gate line and the data line;

an organic insulating film on the gate line, the data line and the thin film transistor, and having a transmission hole in the pixel area;

a pixel electrode on the organic insulating film of the pixel area via the transmission hole and connected to the thin film transistor; and

a reflective electrode on the pixel electrode having a same edge part as the pixel electrode or an edge part located at inner side from an edge part of the pixel electrode and exposing the pixel electrode of the transmission hole.

2. The liquid crystal display device according to claim 1, wherein the organic insulating film and the pixel electrode have an embossing surface.

3. The liquid crystal display device according to claim 2, wherein the reflective electrode has the same embossing surface.

4. The liquid crystal display device according to claim 1, wherein the reflective electrode is connected to the pixel electrode and encloses a lateral surface of the transmission hole.

5. The liquid crystal display device according to claim 1, further comprising a passivation film under the organic insulating film.

6. The liquid crystal display device according to claim 5, wherein the passivation film is formed of an inorganic insulating material.

7. The liquid crystal display device according to claim 1, wherein the transmission hole passes through the organic insulating film and the gate insulating film.

8. The liquid crystal display device according to claim 1, wherein the pixel electrode is connected to a drain electrode of the thin film transistor via a drain contact hole passing through the organic insulating film.

9. The liquid crystal display device according to claim 1, wherein the reflective electrode and the pixel electrode overlap at least one of the gate line and the data line.

10. The liquid crystal display device according to claim 1, further comprising:

a storage capacitor including a storage line, the storage line crossing the data line; and

a drain electrode, wherein the storage line is overlapped with the drain electrode extended from the thin film transistor with the gate insulating film therebetween.

11. The liquid crystal display device according to claim 1, further comprising a semiconductor pattern overlapped with the data line and the thin film transistor.

12. The liquid crystal display device according to claim 1, further comprising a pad connected to at least one of the gate line and the data line.

13. The liquid crystal display device according to claim 12, wherein the pad includes:

a lower pad electrode connected to at least one of the gate line and data line;

a contact hole passing through the organic insulating film and the gate insulating film to expose the lower pad electrode;

an upper pad electrode connected to the lower pad electrode via the contact hole.

14. The liquid crystal display device according to claim 13, further comprising:

a data link extended from the lower pad electrode and adjacent to the data line;

a plurality of contact holes exposing the data link and the data line; and

a contact electrode passing through the contact holes to connect to the data link and the data line.

15. The liquid crystal display device according to claim 14, wherein the contact electrode includes at least one of a transparent conductive film same as the pixel electrode and a reflective metal layer same as the reflective electrode.

16. The liquid crystal display device according to claim 15, wherein the contact electrode is formed of the transparent conductive film and the reflective metal layer.

17. The liquid crystal display device according to claim 16, wherein the reflective metal layer is formed to have the same edge part as the transparent conductive film or to have an edge part located at an inner part from the edge part of the transparent conductive film.

18. The liquid crystal display device according to claim 14, wherein the contact electrode is located at an area to be sealed by a sealant.

19. The liquid crystal display device according to claim 12, wherein the pad is one of a gate pad and a data pad.

20. The liquid crystal display device according to claim 1, further comprising a liquid crystal layer between the first and second substrates.

21. A method of fabricating a liquid crystal display device, comprising:

providing first and second substrates;

forming a gate line on the first substrate using a first mask;

forming a gate insulating film on the first substrate, a semiconductor pattern on the gate insulating film, a data line crossing the gate line to define a pixel area on the semiconductor pattern, a source electrode, and a drain electrode using a second mask;

forming an organic insulating film on the data line, the source electrode and the drain electrode and forming a transmission hole passing through the organic insulating film using a third mask; and

forming a pixel electrode connected to the drain electrode, passing through the organic insulating film and the transmission hole and forming a reflective electrode exposing the pixel electrode of the transmission hole on the pixel electrode using a fourth mask.

22. The method according to claim 21, wherein:

the first mask further includes forming a storage line substantially parallel to the gate line on the first substrate; and

the second mask further includes forming a storage capacitor overlapping the storage line with the gate insulating film therebetweeen by extending the drain electrode and the semiconductor pattern.

23. The method according to claim 21, wherein:

the first mask further includes forming a lower pad electrode connected to at least one of the gate line and the data line;

the third mask further includes forming a contact hole exposing the lower pad electrode during the third mask process; and

the fourth mask further includes forming an upper pad electrode connected to the lower pad electrode via the contact hole during the fourth mask process.

24. The method according to claim 23, wherein:

the first mask further includes forming a data link extended from the lower pad electrode and connected to the data line;

the third mask further includes forming a plurality of contact holes exposing the data link and the data line; and

the fourth mask further includes forming a contact electrode connected to the data link and the data line through the contact holes.

25. The method according to claim 24, wherein the contact electrode includes at least one of a transparent conductive film same as the pixel electrode and a reflective metal layer same as the reflective electrode.

26. The method according to claim 24, wherein the contact electrode is located at an area to be sealed by a sealant.

27. The method according to claim 21, wherein the reflective electrode is connected to the pixel electrode and encloses a lateral surface of the transmission hole.

28. The method according to claim 24, wherein the fourth mask further comprising:

forming a transparent conductive film and a reflective metal layer on the organic insulating film;

forming first and second photo-resist patterns having different thicknesses on the reflective metal layer;

patterning the transparent conductive film and the reflective metal layer by an etching using the first and the second photo-resist patterns as a mask to form a transparent conductive pattern, having the pixel electrode, the upper pad electrode and the contact electrode, and a reflective electrode having an edge part same as the transparent conductive pattern;

removing the pixel electrode in the transmission hole and the reflective electrode on the upper pad electrode by an etching using the first photo-resist pattern as a mask; and

removing the first photo-resist pattern.

29. The method according to claim 28, wherein the first and the second photo-resist patterns are formed by a photolithography process using one of a diffractive exposure mask, a half-tone mask, and a partial exposure mask.

30. The method according to claim 29, wherein the photolithography process has two exposure processes using first and second partial exposure masks in a case of the partial exposure mask.

31. The method according to claim 29, wherein the first photo-resist pattern corresponds to a shielding layer in the first and the second partial exposure masks, and the second photo-resist pattern corresponds to a shielding layer in the first partial exposure mask.

32. The method according to claim 21, wherein the third mask further comprising forming a passivation film under the organic insulating film.

33. The method according to claim 32, wherein the passivation film is formed of an inorganic insulating material.

34. The method according to claim 32, wherein the transmission hole passes through the organic insulating film to the gate insulating film.

35. The method according to claim 21, wherein the transmission holes passes through the organic insulating film to the gate insulating film.

36. The method according to claim 21, wherein the third mask further comprising forming a drain contact hole passing through the organic insulating film to expose the drain electrode, wherein the pixel electrode is connected to the drain electrode via the drain contact hole.

37. The method according to claim 21, wherein the reflective electrode and the pixel electrode overlap at least one of the gate line and the data line.

38. The method according to claim 21, wherein an edge part of the pixel electrode and an edge part of the reflective electrode are formed different from each other.