Liquid Crystal Display Device and Method for Fabricating the Same

• US 20130162926A1
• Filed: 10/15/2012
• Published: 06/27/2013
• Est. Priority Date: 12/21/2011
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Park, Mun-Gi, Jang, Jin-Hee, Kwack, Hee-Young
• Granted Patent: US 8,885,128 B2
• Time in Patent Office: Days
• US Class Current: 349/43
• CPC Class Codes: G02F 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/136231 for reducing the number of lithographic steps
• CPC Class Codes: H01L 27/1248 with a particular composition or shape of the interlayer dielectric specially adapted to the circuit arrangement
• CPC Class Codes: H01L 27/1288 employing particular masking sequences or specially adapted masks, e.g. half-tone mask

Abstract

Disclosed are a liquid crystal display device which reduces the number of masks and improves an aperture ratio, and a method for fabricating the same. The liquid crystal display device includes gate and data lines perpendicularly intersecting on a substrate having pixel and pad parts; a thin film transistor on the substrate at the intersection of the gate and data lines; a pixel electrode on the substrate at the pixel part and connected directly to a drain electrode of the thin film transistor; an insulating film on the overall surface of the substrate including the pixel electrode and the thin film transistor; an organic film on the insulating film over the thin film transistor and the data line; and a common electrode of slit shapes overlapping the pixel electrode such that the insulating film is interposed between the common electrode and the pixel electrode.

Claims

1. A liquid crystal display device comprising:

gate and data lines perpendicularly intersecting on a substrate having pixel and pad parts;

a thin film transistor on the substrate at the intersection of the gate and data lines;

a pixel electrode on the substrate at the pixel part and connected directly to a drain electrode of the thin film transistor;

an insulating film on the overall surface of the substrate including the pixel electrode and the thin film transistor;

an organic film on the insulating film over the thin film transistor and the data line; and

a common electrode of slit shapes overlapping the pixel electrode such that the insulating film is interposed between the common electrode and the pixel electrode.

2. The liquid crystal display device according to claim 1, wherein the organic film includes at least one selected from the group consisting of carbon, titanium oxide, a color pigment and a black resin.

3. The liquid crystal display device according to claim 1, wherein the organic film is formed of a photo active compound (PAC).

4. The liquid crystal display device according to claim 1, wherein the organic film exposes the insulating film over the pixel electrode.

5. The liquid crystal display device according to claim 1, wherein the pad part includes:

a gate pad lower electrode connected to the gate line;

a data pad lower electrode connected to the data line;

a gate pad upper electrode connected to the gate pad lower electrode; and

a data pad upper electrode connected to the data pad lower electrode,

wherein the gate pad upper electrode and the data pad upper electrode is formed of the same layer as the common electrode.

6. A method for fabricating a liquid crystal display device comprising:

forming a gate line, a gate electrode and a gate pad lower electrode on a substrate using a first mask;

forming a gate insulating layer on an entire surface of the substrate including the gate line, the gate electrode and the gate pad lower electrode;

forming a semiconductor layer on the gate insulating layer over the gate electrode using a second mask;

forming a pixel electrode on the gate insulating layer using a third mask;

forming a data line and a data pad lower electrode on the gate insulating layer, and a source electrode and a drain electrode separated from the source electrode and connected directly to the pixel electrode on the semiconductor layer using a fourth mask, thereby forming a thin film transistor including the gate electrode and the source and drain electrodes;

forming an insulating film on an entire surface of the substrate including the data line and the source and drain electrodes;

forming an organic material layer on the insulating film over the thin film transistor and the data line using a fifth mask so that contact holes are formed on the gate and data pad lower electrodes; and

forming a common electrode of slit shapes on the substrate to overlap with the pixel electrode using a sixth mask such that the insulating film is interposed between the common electrode and the pixel electrode.

7. The method according to claim 6, further comprising:

forming a gate pad upper electrode connected to the gate pad lower electrode, and a data pad upper electrode connected to the data pad lower electrode,

wherein the gate pad upper electrode and the data pad upper electrode is formed of the same layer as the common electrode.

8. The method according to claim 6, wherein the step of forming an organic material layer includes:

forming an organic material on an entire surface of the insulating film,

forming an organic film pattern by exposing and developing the organic material using a half tone mask as the fifth mask, wherein the half tone mask includes a transmitting region corresponding to the gate and data pad lower electrodes, a blocking region corresponding to the data line and the thin film transistor and a semi-transmitting region corresponding to remaining areas, and

ashing the organic film pattern to form the organic material layer.

9. The method according to claim 6, wherein the organic material layer includes at least one selected from the group consisting of carbon, titanium oxide, a color pigment and a black resin.

10. The method according to claim 6, wherein the organic material layer is formed of a photo active compound (PAC).