Liquid crystal display device and method for manufacturing the same

• US 20030122985A1
• Filed: 12/19/2002
• Published: 07/03/2003
• Est. Priority Date: 12/28/2001
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: Dae Lim Park, Seong Soo Hwang, Su Hwan Moon, Young Sik Kim
• Inventors: Moon, Su Hwan, Kim, Young Sik, Hwang, Seong Soo, Park, Dae Lim
• Granted Patent: US 6,847,413 B2
• Time in Patent Office: Days
• US Class Current: 349/43
• 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
• CPC Class Codes: G02F 1/136236 using a grey or half tone lithographic process

Abstract

A liquid crystal display device and a method for manufacturing the same are provided. The device and method increase contact stability by forming a contact hole exposing the lateral and upper surfaces of a metal layer using a diffraction mask. The device includes a lower metal layer on a substrate; a passivation layer on the substrate including the lower metal layer; a contact hole on the passivation layer so as to expose the lateral and upper surfaces of the lower metal layer; and an upper metal layer in the contact hole and over the passivation layer, and in contact with the exposed lateral and upper surface of the lower metal layer.

Claims

1. A liquid crystal display device comprising:

a lower metal layer on a substrate;

a passivation layer on the substrate including the lower metal layer;

a contact hole on the passivation layer so as to expose at least portions of lateral and upper surfaces of the lower metal layer; and

an upper metal layer in the contact hole and over the passivation layer adjacent to the contact hole, and being in contact with the exposed portions of the lateral and upper surfaces of the lower metal layer.

2. The device of claim 1, wherein the lower metal layer is made of Mo.

3. The device of claim 1, wherein the lower metal layer having the exposed portions of the lateral and upper surfaces is used as a drain electrode of the liquid crystal display device.

4. The device of claim 1, wherein the lower metal layer having the exposed portions of the lateral and upper surfaces is used as an upper electrode of a storage capacitor in the liquid crystal display device.

5. A method of manufacturing a liquid crystal display device, comprising the steps of:

forming a metal layer on an insulating layer;

forming a passivation layer on the metal layer;

forming a photoresist pattern having an opening exposing a predetermined portion of the passivation layer and having at least two areas differing in thickness from each other;

forming a contact hole exposing portions of lateral and upper surfaces of the metal layer by selectively etching the passivation layer using the photoresist pattern as an etch mask;

removing the photoresist pattern; and

forming a transparent conductive material to be in contact with the exposed portions of the lateral and upper surfaces of the metal layer through the contact hole.

6. The method of claim 5, wherein the metal layer is formed of Mo.

7. The method of claim 5, wherein the step of forming the photoresist pattern includes the steps of:

coating a photoresist layer on the passivation layer;

applying light beams to the photoresist layer using a diffraction mask having a predetermined slit pattern; and

developing the photoresist layer to form the photoresist pattern.

8. The method of claim 7, wherein the photoresist pattern includes a step-like pattern.

9. The method of claim 5, wherein the passivation layer is etched by using a (SF₆+Cl₂) gas having an O₂ gas added thereto.

10. A method of manufacturing a liquid crystal display device, comprising the steps of:

forming a semiconductor layer over a gate line on a substrate;

forming source and drain electrodes overlapped with sides of the semiconductor layer and forming an opaque metal layer overlapped with the gate line;

forming a photoresist pattern having openings exposing predetermined portions of the passivation layer over the drain electrode and the opaque metal layer respectively, wherein the photoresist pattern has at least two areas differing in thickness from each other;

forming first and second contact holes exposing at least portions of lateral and upper surfaces of the opaque metal layer and the drain electrode respectively by selectively etching the passivation layer using the photoresist pattern as an etch mask;

removing the photoresist pattern; and

forming a transparent conductive material to be in. contact with the opaque metal layer and the drain electrode exposed through the first and second contact holes, respectively.

11. The method of claim 10, wherein the opaque metal layer, the source electrode, and the drain electrode are formed of Mo.

12. The method of claim 10, wherein the step of forming the photoresist pattern includes the steps of:

coating a photoresist layer on the passivation layer;

applying light beams to the photoresist layer using a diffraction mask having a predetermined slit pattern; and

developing the photoresist layer to form the photoresist pattern.

13. The method of claim 12, wherein the photoresist pattern includes a step-like pattern.

14. The method of claim 10, wherein the passivation layer is etched by using a (SF₆+Cl₂) gas having an O₂ gas added thereto.

15. The method of claim 12, wherein a portion of the photoresist pattern under the slit pattern is thinner than other portions of the photoresist pattern.

16. The method of claim 15, wherein the thinner portion of the photoresist pattern is etched simultaneously when the passivation layer is etched in the step of forming the first and second contact holes.

17. The method of claim 10, further comprising:

forming an insulating layer between the gate line and the semiconductor layer.

19. The method of claim 17, wherein the step of forming the photoresist pattern includes the steps of:

coating a photoresist layer on the passivation layer;

performing an exposing and developing process to the photoresist layer using a diffraction mask having a predetermined slit pattern; and

removing the photoresist layer corresponding to the first and second areas at a predetermined thickness to form the photoresist pattern.

18. A method of manufacturing a liquid crystal display device, comprising the steps of:

forming a gate line on a substrate;

forming a semiconductor layer over the gate line;

forming source and drain electrodes overlapped with sides of the semiconductor layer;

forming an opaque metal layer overlapped with the gate line;

forming a passivation layer on the substrate including the source and drain electrodes and the opaque metal layer;

forming a photoresist pattern having thinner portions corresponding to first and second areas of the passivation layer;

forming first and second contact holes in the first and second areas of the passivation layer by using the photoresist pattern as a mark and thereby exposing portions of the opaque metal layer and the drain electrode;

removing the remaining photoresist pattern; and

forming a transparent conductive material to be in contact with the opaque metal layer and the drain electrode exposed through the first and second contact holes, respectively.

20. The method of claim 18, further comprising:

forming an insulating layer between the gate line and the semiconductor layer.