Liquid crystal display device and method of fabricating the same

• US 7,279,383 B2
• Filed: 06/25/2004
• Issued: 10/09/2007
• Est. Priority Date: 06/30/2003
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: You, JaeSung
• Primary Examiner(s): LOUIE, WAI SING
• Application Number:
  US10/875,308
• Publication Number:
  US 20040263703A1
• Time in Patent Office: 1,201 Days
• Field of Search: None
• US Class Current: 438/254
• CPC Class Codes: G02F 1/136231 for reducing the number of lithographic steps
• CPC Class Codes: G02F 1/136277 formed on a semiconductor substrate, e.g. of silicon
• CPC Class Codes: Y10S 438/924 To facilitate selective etching

Abstract

There is disclosed a liquid crystal display device and a fabricating method thereof that reduce the number of processes and production cost. A liquid crystal display device and a fabricating method thereof according to an embodiment of the present invention forms a poly-silicon pattern by partially crystallizing an amorphous silicon, and simultaneously etches the amorphous silicon and the poly-silicon pattern, thereby removing the amorphous silicon and leaving the poly-silicon pattern on the substrate.

Claims

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

forming an amorphous silicon on a substrate;

forming a poly-silicon pattern in the amorphous silicon by partially crystallizing the amorphous silicon; and

simultaneously etching the amorphous silicon and the poly-silicon pattern using an etching ratio of the amorphous silicon and the poly-silicon pattern to remove the amorphous silicon and leave the poly-silicon pattern on the substrate in absence of a photo-resist.

2. The fabricating method according to claim 1, wherein the poly-silicon pattern is an active layer included in each of a plurality of thin film transistors.

3. The fabricating method according to claim 1, wherein the poly-silicon pattern is an aligning mark.

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

forming a buffer layer on a substrate;

forming an amorphous silicon on the buffer layer;

forming a poly-silicon pattern by partially irradiating a laser beam on the amorphous silicon and inducing the growth of crystal from the side surface of an area on which the laser beam is irradiated; and

simultaneously etching the amorphous silicon and the poly-silicon using an etching ratio of the amorphous silicon and the poly-silicon pattern to remove the amorphous silicon and leave the poly-silicon pattern on the substrate in absence of a photo-resist pattern.

5. The fabricating method according to claim 4, wherein the poly-silicon pattern is an active layer included in each of a plurality of thin film transistors.

6. The fabricating method according to claim 4, wherein the poly-silicon pattern is an aligning mark.

7. The fabricating method according to claim 5, further comprising the steps of:

forming a gate insulating film on the buffer layer to cover the poly-silicon pattern;

forming a gate electrode of the thin film transistor that partially overlaps with the poly-silicon pattern by forming a gate metal layer on the gate insulating film and patterning the gate metal layer;

forming a doping area on the poly-silicon pattern by injecting impurities at a low concentration into the poly-silicon pattern other than the part thereof that overlaps with the gate electrode by using the gate electrode as a mask;

forming a source area and a drain area on the poly-silicon pattern by injecting impurities at a high concentration into part of the doping area;

forming a interlayer insulating film on the gate insulating film to cover the gate electrode and forming a first contact hole that runs through the interlayer insulating film and the gate insulating film to expose the source area and the drain area;

forming a source electrode of the thin film transistor connected to the source area and a drain electrode of the thin film transistor connected to the drain area;

forming a protective film on the interlayer insulating film to cover the source electrode and the drain electrode; and

forming a second contact hole on the protective film to expose the drain electrode and forming a pixel electrode connected to the drain electrode.

8. A fabricating method of a liquid crystal display device having a plurality of thin film transistors, comprising:

forming an amorphous silicon layer on a substrate;

partially crystallizing the amorphous silicon layer using a laser annealing method,

wherein the partially crystallized silicon layer has a poly-silicon region and an amorphous silicon region; and

etching the partially crystallized silicon layer to remove the amorphous silicon region and leave the poly-silicon region on the substrate without using a photo-resist pattern.

9. The fabricating method according to claim 8, wherein the laser annealing method is a sequential lateral solidification (SLS) method.

10. The fabricating method according to claim 8, wherein the poly-silicon region is an active layer included in each of the thin film transistors.

11. The fabricating method according to claim 8, wherein the poly-silicon region is an aligning mark.

12. The fabricating method according to claim 8, wherein etching the partially crystallized silicon layer includes subjecting the amorphous silicon region and the poly-silicon region to an etching condition at the same time.

13. The fabricating method according to claim 8, wherein the thin film transistors are a top-gate type.