Method of fabricating a liquid crystal display device

• US 8,294,855 B2
• Filed: 07/13/2009
• Issued: 10/23/2012
• 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
• Primary Examiner(s): Merlin, Jessica M
• Application Number:
  US12/458,456
• Publication Number:
  US 20090275155A1
• Time in Patent Office: 1,198 Days
• Field of Search: 349/114, 349/149, 349/153, 349/152, 349/187
• 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 method of fabricating a liquid crystal display device, comprising:

providing first and second substrates;

forming a gate line on the first substrate, a lower gate pad electrode connected to the gate line, a lower data pad electrode, and a data link extended from the lower data pad electrode, using a first mask during a first mask process;

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 during a second mask process;

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, a gate pad contact hole exposing the lower gate pad electrode, a data pad contact hole exposing the lower data pad electrode, and a plurality of contact holes exposing the data link and the data line, using a third mask during a third mask process; and

forming a pixel electrode connected to the drain electrode, passing through the organic insulating film and the transmission hole, forming a reflective electrode on the pixel electrode in a reflective area of the pixel and exposing the pixel electrode in the transmission hole, forming an upper gate pad electrode connected to the lower gate pad electrode via the gate pad contact hole, forming an upper data pad electrode connected to the lower data pad electrode via the data pad contact hole, and forming a contact electrode connected to the data link and the data line through the plurality of contact holes, using a fourth mask during a fourth mask process, in which the contact electrode includes a transparent conductive film same as the pixel electrode and a reflective metal layer same as the reflective electrode,

wherein the fourth mask process further comprises;

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

forming first and second photo-resist patterns on the reflective metal layer using the fourth mask, wherein the first photo-resist pattern is thicker than that of the second photo-resist pattern;

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 and a reflective electrode, wherein the transparent conductive pattern has the pixel electrode, the upper pad electrode and the contact electrode, and the reflective electrode has an edge part same as the transparent conductive pattern;

removing the second photo-resist pattern and thinning the first photo-resist pattern;

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

removing the first photo-resist pattern.

2. The method according to claim 1, wherein:

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

the second mask process 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.

3. The method according to claim 1, wherein the contact electrode is located at an area to be sealed by a sealant.

4. The method 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 method according to claim 1, 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.

6. The method according to claim 5, wherein the photolithography process has two exposure processes using first and second partial exposure masks in a case of the partial exposure mask.

7. The method according to claim 5, 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.

8. The method according to claim 1, wherein the third mask process further comprises forming a passivation film under the organic insulating film.

9. The method according to claim 8, wherein the passivation film is formed of an inorganic insulating material.

10. The method according to claim 8, wherein the transmission hole passes through the organic insulating film to the gate insulating film.

11. The method according to claim 1, wherein the transmission hole passes through the organic insulating film to the gate insulating film.

12. The method according to claim 1, wherein the third mask process further comprises 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.

13. The method according to claim 1, wherein the reflective electrode and the pixel electrode overlap at least one of the gate line and the data line.

14. The method according to claim 1, wherein the pixel electrode has a different edge from an edge part of the reflective electrode.