Liquid crystal display device and fabricating method thereof

• US 20060146255A1
• Filed: 12/21/2005
• Published: 07/06/2006
• Est. Priority Date: 12/31/2004
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Ahn, Byung Chul
• Granted Patent: US 7,564,529 B2
• Time in Patent Office: Days
• US Class Current: 349/141
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• CPC Class Codes: G02F 1/13458 Terminal pads
• CPC Class Codes: G02F 1/136209 Light shielding layers, e.g. black matrix, incorporated in the active matrix substrate, e.g. structurally associated with the switching element
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/136231 for reducing the number of lithographic steps
• CPC Class Codes: G02F 1/136236 using a grey or half tone lithographic process
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/13629 Multilayer wirings
• CPC Class Codes: G02F 1/136295 Materials; Compositions; Manufacture processes

Abstract

A thin film transistor substrate of fringe field switching type and a fabricating method thereof for simplifying a process are disclosed. In the thin film transistor substrate of fringe field switching type, a gate line has a multiple-layer structure and includes a transparent conductive layer. A data line crosses the gate line to define a pixel area. A thin film transistor is connected to the gate line and the data line. A common line is provided in a multiple-layer structure and in parallel to the gate line. A common electrode is formed by an extension of a transparent conductive layer of the common line at said pixel area. A pixel electrode is connected to the thin film transistor to form a fringe field with the common electrode in the pixel area.

Claims

1. A liquid crystal display device, comprising:

a multiple-layer structure gate line having a transparent conductive layer;

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;

a common line formed in parallel to the gate line and having the multiple-layer structure;

a common electrode formed by an extension of a transparent conductive layer of the common line in the pixel area; and

a pixel electrode connected to the thin film transistor to form a fringe field with the common electrode in the pixel area.

2. The device as claimed in claim 1, wherein a storage capacitor provided such that the common electrode overlaps with the pixel electrode with an insulating film.

3. The device as claimed in claim 1, wherein the common electrode has a plate shape and the pixel electrode has a rib shape.

4. The device as claimed in claim 1, wherein the pixel electrode overlaps with the common electrode with a gate insulating film between the gate line and data line and a protective film on the data line.

5. The device as claimed in claim 4, wherein the pixel electrode is connected to a drain electrode of the thin film transistor via a contact hole passing through the protective film.

6. The device as claimed in claim 1, wherein a semiconductor pattern extends along the data line.

7. The device as claimed in claim 1, further comprising:

a pad connected to at least one of the gate line, the data line and the common line,

wherein the pad includes;

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

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

8. The device as claimed in claim 7, wherein the lower pad electrode connected to the at least one of the common line and gate line having a multiple-layer structure.

9. The device as claimed in claim 7, wherein the lower pad electrode connected to the data line overlaps with the semiconductor pattern extended along the data line.

10. The device as claimed in claim 1, wherein the multiple-layer structure having the transparent conductive layer is a layer structure having the transparent conductive layer and the upper conductive layer and having step coverage taking a stepwise shape.

11. The device as claimed in claim 1, further comprising:

a shielding pattern on the common electrode along at least one outer side of the common electrode.

12. The device as claimed in claim 1, wherein the pixel electrode is formed on a basis of the common line.

13. The device as claimed in claim 12, further comprising at least one shielding pattern extended, in parallel to the data line, from the common line.

14. The device as claimed in claim 12, further comprising a shielding pattern formed along at least one outer side of the common electrode.

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

a first mask process forming a first mask pattern group including a gate line and a common line having a multiple-layer structure of a transparent conductive layer, and a common electrode extended from the transparent conductive layer of the common electrode, on a substrate;

a second mask process forming a gate insulating film on the first mask pattern group, forming a semiconductor pattern on the gate insulating film, and forming a source/drain metal pattern including a data line, a source electrode and a drain electrode overlapped with each other on the semiconductor pattern;

a third mask process forming a protective film on the source/drain metal pattern and a contact hole for exposing the drain electrode; and

a fourth mask process forming a pixel electrode connected to the drain electrode via the contact hole and overlapped with the common electrode.

16. The method as claimed in claim 15, wherein a storage capacitor is provided such that the common electrode overlaps with the pixel electrode with the gate insulating film and the protective film.

17. The method as claimed in claim 15, wherein the first mask process includes:

forming a conductive layer of the multiple-layer structure of on the substrate;

forming a different thickness of the first and second photo-resist patterns on the conductive layer by a photolithography using one of a half tone mask and a diffractive exposure mask;

forming the gate pattern, the common line and a multiple-layer structure of common electrode by patterning the conductive layer of multiple-layer structure by an etching process using the first and second photo-resist patterns;

removing the second photo-resist pattern and an upper conductive layer of the exposed common electrode to thereby expose the transparent conductive layer; and

removing the first photo-resist pattern.

18. The method as claimed in claim 15, wherein the first mask process includes forming a lower pad electrode of the multiple-layer structure connected to at least one of the gate line and the common line,

the third mask process includes forming a second contact hole for exposing the lower pad electrode, and

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

19. The method as claimed in claim 15, wherein the second mask process includes forming a lower pad electrode extended, along with the semiconductor pattern, from the data line,

the third mask process includes forming a second contact hole for exposing the lower pad electrode, and

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

20. The method as claimed in claim 15, wherein the upper conductive layer or the source/drain metal layer of the conductive layer of the multiple-layer structure includes one of a single layer formed of one of Mo, Ti, Cu, AlNd, Al, Cr, a Mo-alloy, a Cu-alloy or an Al-alloy, a double layer and a triple layer formed of one of Al/Cr, Al/Mo, Al(Nd)/Al, Al(Nd)/Cr, Mo/Al(Nd)/Mo, Cu/Mo, Ti/Al(Nd)/Ti, Mo/Al, Mo/Ti/Al(Nd), Cu-alloy/Mo, Cu-alloy/Al, Cu-alloy/Mo-alloy, Cu-alloy/Al-alloy, Al/Mo-alloy, Mo-alloy/Al, Al-alloy/Mo-alloy, Mo-alloy/Al-alloy, Mo/Al-alloy, Cu/Mo-alloy, and Cu/Mo(Ti).

21. The method as claimed in claim 15, further comprising:

forming a shielding pattern on the common electrode along at least one outer side of the common electrode.

22. The method as claimed in claim 15, wherein the pixel electrode is formed on a basis of the common line.

23. The method as claimed in claim 22, further comprising:

forming at least one shielding pattern extended, in parallel to the data line, from the common line.

24. The method as claimed in claim 22, further comprising:

forming a shielding pattern along at least one outer side of the common electrode.