Liquid crystal display device and method of manufacturing the same

• US 6,433,842 B1
• Filed: 03/29/2000
• Issued: 08/13/2002
• Est. Priority Date: 03/26/1999
• Status: Expired due to Term

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamamoto, Hideaki, Takahashi, Takuya, Ochiai, Takahiro, Terakado, Masatomo, Tamura, Katsumi, Kaneko, Toshiki, Takabatake, Masaru, Onisawa, Kenichi, Harano, Yuichi, Cyahara, Kenichi
• Primary Examiner(s): Ton, Toan
• Assistant Examiner(s): NGUYEN, HOAN C
• Application Number:
  US09/537,395
• Time in Patent Office: 867 Days
• Field of Search: 349/139, 349/43, 349/44, 349/46
• US Class Current: 349/43
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/13629 Multilayer wirings

Abstract

The method of fabrication of a liquid crystal display device includes the steps of: forming a metal thin film on a glass substrate; forming a resist pattern on the metal thin film by photolithography; and wet-etching the metal thin film with an etchant formed of a mixture including phosphoric acid, nitric acid in a range between 7 mol % and 12 mol % inclusive, and at least one of ammonium fluoride and hydrogen fluoride in a trace amount of about 0.01 to 0.1 mol %.

Claims

1. A liquid crystal display device comprising:

a pair of substrates;

a liquid crystal layer interposed between said pair of substrate; and

drain lines and gate lines formed on one of said pair of substrates and cross each other in a matrix form;

wherein at least one of said drain lines and gate lines has a layered structure formed of a first conductive layer and a second conductive layer;

and said first conductive layer includes Al as a main component and said second conductive layer includes Mo in a range between 77 wt. % to 96 wt. % and Zr in a range between 4 wt. % to 23 wt. %.

2. The liquid crystal display device according to claim 1, wherein said second conductive layer includes Mo containing Zr and Hf as a main component.

3. The liquid crystal display device according to claim 1, wherein said gate lines have a layered structure formed of said first and second conductive layers.

4. The liquid crystal display device according to claim 1, further comprising at least a pair of a pixel electrode and a counter electrode formed on one of the pair of substrates in each of a plurality of pixels respectively defined by said plurality of gate lines and drain lines, wherein an image signal is supplied from a drain line to a pixel electrode via a thin film transistor driven based on supply of a scanning signal from a gate line, and a counter voltage signal line is connected to said counter electrode, said counter voltage signal line or said counter electrode having a layered structure formed of said first and second conductive layers.

5. The liquid crystal display device according to claim 4, wherein said gate lines are in the same layer as said counter voltage signal line and said counter electrode,

the drain lines are in a layer above said gate lines via a first insulating film, and said pixel electrodes are in a layer above the drain lines via a second insulating film, said pixel electrodes being connected with the layer including Mo containing Zr as a main component via connecting means formed through said second insulating film.

6. The liquid crystal display device according to claim 5, wherein said pixel electrodes are made of either ITO or IZO.

7. The liquid crystal display device according to claim 4, wherein said first conductive layer including Al as a main component has been anodized.

8. The liquid crystal display device according to claim 1, wherein said first conductive layer including Al as a main component has been anodized.

9. The liquid crystal display device according to claim 1, wherein said second conductive layer is formed on said first conductive layer, and the sectional shape of said first conductive layer is a tapered shape.

10. The liquid crystal display according to claim 1, wherein the first conductive layer is an Al—

Nd alloy.

24. The liquid crystal display device according to claim 7, wherein said second conductive layer is formed on said first conductive layer, and the sectional shape of said first conductive layer is a tapered shape.

11. A liquid crystal display device comprising:

a pair of substrates;

a liquid crystal layer interposed between said pair of substrates; and

drain lines and gate lines formed on one of said pair of substrates and crossing each other in a matrix form;

wherein at least one of said drain lines and gate lines has a layered structure formed of a first conductive layer and a second conductive layer; and

said first conductive layer includes Al as a main component and said second conductive layer includes Mo in a range between 64 wt. % to 92.7 wt. % and Hf in a range between 7.3 wt. % to 36 wt. %.

12. The liquid crystal display device according to claim 11, wherein said second conductive layer includes Mo containing Zr and Hf as a main component.

13. The liquid crystal display device according to claim 11, herein said gate lines have a layered structure formed of said first and second conductive layers.

14. The liquid crystal display device according to claim 11, wherein said second conductive layer is formed on said first conductive layer, and the sectional shape of said first conductive layer is a tapered shape.

15. The liquid crystal display device according to claim 11, wherein said gate lines are in the same layer as said counter voltage signal line and said counter electrode,

the drain lines are in a layer above said gate lines via a first insulating film, and said pixel electrodes are in a layer above the drain lines via a second insulating film, said pixel electrodes being connected with the layer including Mo containing Zr as a main component via connecting means formed through said second insulating film.

16. The liquid crystal display device according to claim 15, wherein said pixel electrodes are made of either ITO or IZO.

17. The liquid crystal display according to claim 11, wherein the first conductive layer is an Al—

Nd alloy.

18. A liquid crystal display device comprising:

a pair of substrates;

a liquid crystal layer interposed between said pair of substrates; and

drain lines and gate lines formed on one of said pair of substrates and crossing each other in a matrix form;

wherein at least one of said drain lines and gate lines has a layered structure formed of a first conductive layer, a second conductive layer and a third conductive layer, and

said second conductive layer includes Al as a main component, said first and third conductive layers include Mo in a range between 77 wt. % to 96 wt. % and Zr in a range between 4 wt. % and 23 wt. %.

19. The liquid crystal display device according to claim 18, wherein said second conductive layer includes Mo containing Zr and Hf as a main component.

20. The liquid crystal display device according to claim 18, wherein said gate lines have a three-layer structure formed of said first, second, and third conductive layers.

21. The liquid crystal display device according to claim 18, further comprising at least a pair of a pixel electrode and a counter electrode formed on one of the pair of substrates in each of a plurality of pixels respectively defined by the plurality of gate lines and the plurality of drain lines, wherein an image signal is supplied from a drain line to a pixel electrode via a thin film transistor driven based on supply of a scanning signal from a gate line, and a counter voltage signal line is connected to said counter electrode, said counter voltage signal line or said counter electrode having a three-layer structure formed of said first, second and third conductive layers.

22. The liquid crystal display device according to claim 21, wherein said gate lines are in the same layer as said counter voltage signal line and said counter electrode,

the drain lines are in a layer above said gate lines via a first insulating film, and said pixel electrodes are in a layer above the drain lines via a second insulating film, said pixel electrodes being connected with the layer including Mo containing Zr as a main component via connecting means formed through said second insulating film.

23. The liquid crystal display device according to claim 22, wherein said pixel electrodes are made of either ITO or IZO.

25. The liquid crystal display according to claim 18, wherein the second conductive layer is an Al—

Nd alloy.

26. A liquid crystal device comprising:

a liquid crystal layer sandwiched by a pair of substrates;

a plurality of gate lines formed on one of the pair of substrates;

a plurality of drain lines intersecting said gate lines in a matrix shape;

thin film transistors driven in response to supply of a scanning signal from said gate lines;

an image signal supplied from the drain lines to said pixel electrodes via the thin film transistors; and

a counter electrode formed to face said pixel electrodes, a counter voltage being supplied to said counter electrode via a counter voltage signal line,

wherein any of said gate lines, said drain lines, said counter voltage signal line, and said counter electrode have a layered structure formed of a first conductive layer and a second conductive layer, and

said first conductive layer includes Al as a main component and said second conductive layer includes Mo and Zr, the content of the Mo being in a range between 77 wt. % to 96 wt. % and Zr being in a range between 4 wt. % to 23 wt. %.

27. The liquid crystal display device according to claim 26, wherein said gate lines and said counter voltage signal line have a layered structure formed of said first and second conductive layers.

28. The liquid crystal display device according to claim 26, wherein said second conductive layer is formed on said first conductive layer, and the sectional shape of said first conductive layer is a tapered shape.

29. The liquid crystal display device according to claim 26, wherein said gate lines are in the same layer as said counter voltage signal line and said counter electrode,

the drain lines are in a layer above said gate lines via a first insulating film, and said pixel electrodes are in a layer above the drain lines via a second insulating film, said pixel electrodes being connected with the layer including Mo containing Zr as a main component via connecting means formed through said second insulating film.

30. The liquid crystal display device according to claim 29, wherein said pixel electrodes are made of either ITO or IZO.

31. The liquid crystal display according to claim 26, wherein the first conductive layer is an Al—

Nd alloy.

32. A liquid crystal display device comprising:

a liquid crystal layer sandwiched by a pair of substrates;

a plurality of gate lines formed on one of said pair of substrates;

a plurality of drain lines intersecting said gate lines in a matrix shape;

thin film transistors driven in response to supply of a scanning signal from said gate lines; and

an image signal supplied from the drain lines to said pixel electrode via the thin film transistor,

wherein any of said gate lines and drain lines have a layered structure of a first conductive layer and a second conductive layer, and

said first conductive layer includes Al as a main component and said second conductive layer includes Mo, Cr, and Zr, the content of the Mo being in a range between 77 wt. % to 96 wt. %, the content of Zr being in a range between 4 wt. % to 23 wt. %, and the content of Cr being in a range of 0.4 wt. % to 1 wt. %.

33. A liquid crystal display device comprising:

a liquid crystal layer sandwiched by a pair of substrates;

a plurality of gate lines formed on one of the said pair of substrates;

a plurality of drain lines intersecting said gate lines in a matrix shape;

thin film transistors driven in response to supply of a scanning signal from said gate lines; and

an image signal supplied from the drain lines to said pixel electrode via the thin film transistor;

wherein an SiN film is formed on the drain electrode and source electrode of the thin film transistor,

said pixel electrode is formed on the source electrode,

a through hole is formed in the SiN film to connect said pixel electrode and said source electrode,

said source electrode has a layered structure of a first conductive layer and a second conductive layer, and

said first conductive layer includes Al as a main component, and said second conductive layer includes Mo in a range between 77 wt. % to 96 wt. % and Zr in a range between 4 wt. % to 23 wt. %.