Reflective liquid crystal display device

• US 20020075423A1
• Filed: 09/12/2001
• Published: 06/20/2002
• Est. Priority Date: 09/14/2000
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Fujino, Masahiro
• Granted Patent: US 6,943,049 B2
• Time in Patent Office: Days
• US Class Current: 349/43
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• 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 provides a method of manufacturing an active matrix reflecting liquid crystal display device including the step of forming and processing an interlayer insulating film. The step forming and processing an interlayer insulating film includes step A of forming the interlayer insulating film on a silicon film in which the sources and drains of TFTs are formed; step B of forming a photoresist layer on the interlayer insulating film; step C of patterning the photoresist layer in a specified pattern by using, as a photoresist mask for the photoresist layer, a mask having a pattern formed with a resolution limit or less corresponding to the reflecting electrode to be formed; and step D of etching the interlayer insulating film by using the photoresist layer patterned in step C as an etching mask. After step D, a metal film is deposited for simultaneously forming source electrodes, signal wiring, drain electrodes, and the reflecting electrode. The manufacturing method can thus be simplified to improve productivity.

Claims

1. A method of manufacturing an active matrix reflective liquid crystal display device comprising an interlayer insulating film formed on a silicon film in which sources and drains of TFTs are formed, and a reflecting electrode having an irregular surface and formed on the interlayer insulating film, the method comprising the step of forming and processing the interlayer insulating film comprising steps A to D:

step A of forming the interlayer insulating film on the silicon film in which the sources and drains of TFTs are formed;

step B of forming a photoresist layer on the interlayer insulating film;

step C of patterning the photoresist layer by photolithography uses, in which a mask having a pattern formed with a resolution limit or less corresponding to the reflecting electrode to be formed is used as a photoresist mask for the photoresist layer so that portions of the photoresist layer corresponding to contact holes to be formed in the interlayer insulating film above the sources or drains can be completely removed, and surface irregularity can be formed in a portion of the photoresist layer corresponding to the reflecting electrode to be formed; and

step D of etching the interlayer insulating film by using the photoresist layer patterned in step C as an etching mask so that portions of the interlayer insulating film, which correspond to the contact holes to be formed, are completely opened, and surface irregularity is formed in a portion of the interlayer insulating film which corresponds to the reflecting electrode to be formed.

2. A method of manufacturing a liquid crystal display device according to claim 1, wherein the photoresist layer patterned in step C is reflowed and used as an etching mask in step D.

3. A method of manufacturing a liquid crystal display device according to claim 1, wherein step C uses a photomask having a pattern corresponding to the shape of the surface irregularity so that surface irregularity is formed in the interlayer insulating film to increase the reflectance of the reflecting electrode in a specified direction.

4. A method of manufacturing a liquid crystal display device according to claim 1, further comprising, after step D;

step E of depositing a metal film for simultaneously forming source electrodes communicating with the sources through the contact holes, signal wiring, drain electrodes communicating with the drains through the contact holes, and the reflecting electrode;

step F of depositing a protecting film and patterning the protecting film to open portions of the protecting film which correspond to contact holes to be formed above the drain electrodes; and

step G of forming a transparent conductive film on the protecting film so that the transparent conductive film is connected to the reflecting electrode through the contact holes.

5. A method of manufacturing a liquid crystal display device according to claim 4, wherein step F comprises forming the protecting film comprising photoresist and patterning the protecting film by using, as a photoresist mask for the protecting film, a mask having a pattern formed with a resolution limit or less corresponding to the reflecting electrode to be formed, so that the portions of the protecting film corresponding to the contact holes to be formed above the drains can be completely removed, and surface irregularity can be formed in the portion of the protecting film corresponding to the reflecting electrode to be formed.

6. A method of manufacturing a liquid crystal display device according to claim 4 or 5, wherein the thickness of the protecting film is controlled so that the cell gap of a liquid crystal display cell is 1/4λ

.

7. A method of manufacturing a liquid crystal display device according to claim 1, further comprising, after step D;

step E of depositing a metal film for simultaneously forming source electrodes communicating with the sources through the contact holes, signal wiring, drain electrodes communicating with the drains through the contact holes, and the reflecting electrode; and

step G_y of forming a transparent conductive film on the reflecting electrode so that the transparent conductive film is connected to the reflecting electrode.

8. A method of manufacturing a liquid crystal display device according to claim 4, further comprising, after step D;

step E_x of depositing a transparent conductive film for simultaneously forming pattern portions which correspond to source electrodes communicating with the sources through the contact holes, signal wiring, and drain electrodes communicating with the drains through the contact holes, and the reflecting electrode; and

step G_x of forming a transparent conductive film on the reflecting electrode so that the transparent conductive film is connected to the reflecting electrode.

9. An active matrix reflective liquid crystal display device comprising an insulating film formed on a silicon film in which sources and drains of TFTs are formed, and a reflecting electrode having an irregular surface and formed on the insulating film, wherein the insulating layer comprises a single insulating film.

10. A liquid crystal display device according to claim 9, further comprising a transparent conductive film formed on the reflecting electrode so that the transparent conductive film is connected to the reflecting electrode.

11. A liquid crystal display device according to claim 10, further comprising a protecting film provided between the reflecting electrode and the transparent conductive film so that the cell gap of a liquid crystal display cell is set to 1/4λ

.

12. A liquid crystal display device according to claim 11, wherein the surface irregularity is formed in the transparent conductive film formed on the reflecting electrode.

13. A liquid crystal display device according to claim 9, wherein the reflecting electrode is deposited on the insulating layer through the transparent conductive film.