Liquid crystal display device and method for fabricating the same

• US 20030206252A1
• Filed: 04/14/2003
• Published: 11/06/2003
• Est. Priority Date: 09/08/1999
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Ahn, Byung Chul, Yoo, Soon Sung, Kim, Yong Wan, Ha, Young Hun, Lim, Byung Ho
• Granted Patent: US 7,023,501 B2
• Time in Patent Office: Days
• US Class Current: 349/43
• 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

Abstract

A liquid crystal display device and a method of fabricating the same are disclosed. The device, as disclosed, reduces the number of masks required to fabricate. Thus, cost is reduced and yield is increased. The device includes a plurality of gate lines, a plurality of data lines crossing the gate lines such that active regions are defined near the crossover points, thin film transistors are formed near the active regions, and a plurality of pixel electrodes are formed within regions defined by the adjacent gate and data lines. Also, pixel electrodes overlap gate lines and the two electrodes function as a storage capacitor. A fabrication method includes forming a gate line; forming a data line region, protections layers, and an active area where drain and source electrodes are spaced apart a predetermined distance; forming a data line, a gate line protection layer, and a gate insulating layer; and forming pixel electrodes by depositing a transparent conductive material, such that each pixel electrode also overlaps a portion of a gate line.

Claims

1. A method for fabricating a liquid crystal display array panel, comprising:

forming a gate line by depositing a first metal layer on a substrate and patterning the first metal layer using a first mask;

depositing an insulating layer, a pure amorphous silicon layer, a doped amorphous silicon layer and a second metal layer sequentially on the entire surface of the substrate and covering the gate line;

forming a data line region, a gate line protection layer and an active area by patterning the second metal layer and the doped amorphous silicon layer using a second mask, the data line region having a source electrode and the gate line protection layer having a drain electrode spaced at a predetermined distance from the source electrode;

depositing a protection layer on the entire surface of the substrate while covering the data line region, the gate line protection layer and the active area;

forming a data line, a protection film and a gate insulating layer using a third mask;

depositing a transparent conductive material on the entire surface of the substrate while covering the data line and the source and drain electrodes; and

forming a pixel electrode and exposing a portion of the gate line using a fourth mask, the pixel electrode being connected with the drain electrode, the exposed portion extending from the active area.

2. The method according to claim 1, wherein the first metal layer is one of Cr, Mo, and aluminum-based metal.

3. The method according to claim 1, further comprising, a step of removing the exposed portion of the gate line.

4. The method according to claim 1, wherein the transparent conductive material is Indium Zinc Oxide.

5. The method according to claim 1, wherein in the third mask process a contact hole is formed to connect the drain electrode with the pixel electrode.

6. The method according to claim 1, wherein a contact area between the drain electrode and the pixel electrode is larger than a cross section area of the drain electrode.

7. The method according to claim 1, wherein the active area has a “

C”

shape.

8. A method for fabricating a liquid crystal display device, comprising steps of:

forming a gate line by depositing a first metal layer on a substrate and patterning the first metal layer using a first mask;

depositing an insulating layer, a pure amorphous silicon layer, a doped amorphous silicon layer and a second metal layer sequentially on the entire surface of the substrate and covering the gate line;

forming an active area using a second mask by selectively patterning the second metal layer and the pure amorphous silicon layer, the second metal layer covering the entire surface of the substrate except for the active area;

depositing a protection layer on the entire surface of the substrate and covering the data line region, the gate line protection layer and the active area;

forming a data line, a protection film, a gate insulating layer, and source and drain electrodes by patterning the second metal layer, the pure amorphous metal layer, the doped amorphous silicon layer and the insulating layer using a third mask;

depositing a transparent conductive material on the entire surface while covering the data line and the source and drain electrodes; and

forming a pixel electrode and exposing a portion of the gate line using a fourth mask, the pixel electrode being connected with the drain electrode, the exposed portion extending from the active area.

9. The method according to claim 8, wherein the first metal layer is one of Cr, Mo, and aluminum-based metal.

10. The method according to claim 8, further comprising, a step of removing the exposed portion of the gate line.

11. The method according to claim 8, wherein the transparent conductive material is Indium Zinc Oxide.

12. The method according to claim 8, wherein a contact area between the drain electrode and the pixel electrode is larger than a cross section area of the drain electrode.

13. The method according to claim 8, wherein in the third mask process a contact hole is formed to connect the drain electrode with the pixel electrode.

14. The method according to claim 8, wherein the active area has a “

C”

shape.

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

forming a gate line by depositing a first metal layer on a substrate and patterning the first metal layer using a first mask;

depositing an insulating layer, a pure amorphous silicon layer, a doped amorphous silicon layer and a second metal layer sequentially on the entire surface of the substrate and covering the gate line;

forming an active area and a data line region using a second mask by selectively patterning the second metal layer and the pure amorphous silicon layer, the second metal layer away from the data line region and covering the entire surface of the substrate excluding the active area and the data line;

depositing a protection layer on the entire surface of the substrate while covering the data line region, the gate line protection layer and the active area;

forming a data line, a protection film, a gate insulating layer, and source and drain electrodes using a third mask by patterning the second metal layer, the pure amorphous metal layer, the doped amorphous silicon layer and the insulating layer;

depositing a transparent conductive material on the entire surface including the data line and the source and drain electrodes; and

forming a pixel electrode and exposing a portion of the gate line using a fourth mask, the pixel electrode being connected with the drain electrode, the exposed portion extending from the active area.

16. The method according to claim 15, wherein the first metal layer is one of Cr, Mo, and aluminum-based metal.

17. The method according to claim 16, further comprising, a step of removing the exposed portion of the gate line.

18. The method according to claim 15, wherein the transparent conductive material is Indium Zinc Oxide.

19. The method according to claim 15, wherein in the third mask process is formed a contact hole to connect the drain electrode with the pixel electrode.

20. The method according to claim 15, wherein a contacting area between the drain electrode and the pixel electrode is larger than a cross section area of the drain electrode.

21. The method according to claim 15, wherein the active area has a “

C”

shape.

22. A liquid crystal display (LCD) device, comprising:

a plurality of gate lines extending in one direction on a transparent substrate;

a plurality of data lines extending in a perpendicular direction to said gate lines such that active regions are defined at crossover points between said plurality of gate and data lines;

a plurality of gate electrodes formed on said plurality of gate lines near said active regions;

a plurality of source electrodes formed over said plurality of data lines near said active regions;

a plurality of drain electrodes formed over said plurality of gate lines near said active regions;

a protection layer formed on said plurality of drain electrodes; and

a plurality of pixel electrodes formed on said protection layer within regions defined between adjacent gate and data lines, each pixel electrode overlapping at least a portion of a gate line adjacent to said pixel electrode such that said pixel electrode and said portion of gate line electrode form plates of a storage capacitor without an intervening conductor therebetween, and wherein a contact hole is defined over a portion of said pixel electrode such that said pixel electrode fills in sides of said contact hole and said drain electrode contacts said pixel electrode through said sides of said contact hole with said protection layer formed between said pixel electrode and said drain electrode.

23. The LCD device of claim 22, wherein said contact hole is sloped such that a contact area between said pixel electrode and said drain electrode is larger than the thickness of said drain electrode.

24. The LCD device of claim 22, wherein said active area is “

C”

shaped.

25. The LCD device of claim 22, wherein said plurality of gate lines is a dual layered structure of AlNd and Mo.

26. The LCD device of claim 22, wherein said pixel electrode is made of Indium Zinc Oxide.