Liquid crystal display device and method for manufacturing the same

• US 20070069210A1
• Filed: 11/05/2004
• Published: 03/29/2007
• Est. Priority Date: 11/14/2003
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kuwabara, Hideaki, Maekawa, Shinji, Fujii, Gen, Yamazaki, Shunpei
• Granted Patent: US 7,795,616 B2
• Time in Patent Office: Days
• US Class Current: 257/59
• CPC Class Codes: G02F 1/13415 Drop filling process
• 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 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/136295 Materials; Compositions; Manufacture processes
• CPC Class Codes: H01L 27/1292 using liquid deposition, e.g. printing

Abstract

As a substrate gets larger, time of manufacture is increased due to the repetition of film formations and etchings; waste disposal costs of etchant and the like are increased; and material efficiency is significantly reduced. A base film for improving adhesion between a substrate and a material layer formed by a droplet discharge method is formed in the invention. Further, a manufacturing method of a liquid crystal display device according to the invention includes at least one step for forming the following patterns required for manufacturing a liquid crystal display device without using a photomask: a pattern of a material layer typified by a wiring (or an electrode) pattern, an insulating layer pattern; or a mask pattern for forming another pattern.

Claims

1. A liquid crystal display device comprising:

a thin film transistor including a gate electrode formed by a droplet discharge method;

a columnar conductive film formed by a droplet discharge method over a drain electrode of the thin film transistor; and

a pixel electrode connected to the columnar conductive film.

2. The liquid crystal display device according to claim 1,

wherein the gate electrode is formed over an area which is pretreated.

3. The liquid crystal display device according to claim 2,

wherein the area which is pretreated is formed using photocatalyst.

4. The liquid crystal display device according to claim 1,

wherein at least one of the gate electrode, the drain electrode, and the columnar conductive film contains one selected from the group consisting of gold, silver, copper, platinum, palladium, tungsten, nickel, tantalum, bismuth, lead, indium, tin, zinc, titanium, and aluminum.

5. The liquid crystal display device according to claim 1,

wherein the thin film transistor includes an amorphous semiconductor or a semiamorphous semiconductor.

6. A television receiver, wherein the liquid crystal display device according to claim 1 is included in a display screen of the television receiver.

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

forming a gate electrode by a droplet discharge method;

forming a first insulating film over the gate electrode;

forming a semiconductor film over the first insulating film;

forming a mask over the semiconductor film;

patterning the semiconductor film using the mask to form a patterned semiconductor film;

forming a thin film transistor using the patterned semiconductor film by forming source and drain electrodes by a droplet discharge method;

forming a columnar conductive film over one of the source and drain electrodes;

forming a second insulating film covering the columnar conductive film and the thin film transistor; and

forming a pixel electrode connecting the columnar conductive film over the second insulating film.

9. The method for manufacturing the liquid crystal display device according to claim 7 or 8, wherein the method further comprises a step of pretreating an area to where the gate electrode is formed.

10. The method for manufacturing the liquid crystal display device according to claim 9, wherein the step of pretreating uses photocatalyst.

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

forming a gate electrode by a droplet discharge method;

forming a first insulating film over the gate electrode;

forming a semiconductor film over the first insulating film;

forming a mask over the semiconductor film;

patterning the semiconductor film using the mask to form a patterned semiconductor film;

forming a thin film transistor using the patterned semiconductor film by forming source and drain electrodes by a droplet discharge method;

forming a columnar organic film over one of the source and the drain electrodes;

forming a second insulating film covering the columnar organic film and the thin film transistor;

removing the columnar organic film; and

forming a pixel electrode connecting the source or drain electrode over the second insulating film.

11. The method for manufacturing the liquid crystal display device according to claim 8, wherein the second insulating film is repellent to the columnar organic film.

12. The method for manufacturing a liquid crystal display device according to claim 8,wherein the columnar organic film is removed by water washing.