JPS61223721A - Manufacture of liquid crystal display device - Google Patents

Abstract

PURPOSE:To facilitate the manufacturing step and to mass-produce by forming an insulating layer on an optical stopping film contacting with a liquid crystal cell, with an oxidation. CONSTITUTION:The thin film transistor TFT and the display picture element electrode 7 are arranged on the substrate 1 in a matrix state to form the first electrode substrate and the insulating film 8 is coated on the first electrode substrate, and then a metal such as a aluminium is vapor-deposited and is etched to a pattern so as to cover an upper part of TFT, to form the optical stopping film 9 contacting with the liquid crystal 13. The formation of the insulting layer on the optical stopping film 9 is performed by the oxidative treatment according to the anodic oxidation resulting in the formation of the oxidation film 10. Accordingly, the method as mentioned above, makes the step very easy and improves the mass production, on comparing with the earlier method in which the insulating layer is formed with the vapor-deposition or the sputtering method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing an active material type liquid crystal display device using, for example, a thin film transistor (hereinafter referred to as TPT) as an active element.

[Technical background of the invention and its problems]

Recently, as for display devices using liquid crystals or electroluminescence (EL), large-capacity, high-density active matrix display devices aimed at television displays, graphic displays, etc. have been actively developed and put into practical use. In such display devices, active elements are used as means for driving and controlling each pixel so as to perform high contrast display without crosstalk. The active element is a MOf9FET formed on a single crystal St substrate.
Recently, mini T formed on a transparent insulating substrate has been developed because it enables transmissive display and it is easy to increase the area.
PT etc. are used.

Among such active elements, TPT uses amorphous silicon (hereinafter referred to as a-8i) as a semiconductor base material,
Many of them are of field effect type using CdSe, Cd8, etc. These semiconductor base materials have a large absorption coefficient for visible light. Therefore, in the case of a liquid crystal display device that transmits or reflects outside light, in order to prevent light from entering the active area of the TPT and causing it to be constantly in a conductive state, for example, in an inverted staggered TPT, the active area of the TPT is A thin metal film may be provided on one side with an insulating layer in between as a mask to shield the source.

However, in this case, liquid crystal C: ε
However, it is necessary to form an insulating layer by vapor deposition or sputtering to cover the thin metal film that serves as a mask for blocking light, which complicates the manufacturing process and impairs mass productivity.

[Purpose of the invention]

The present invention has been made in view of these points, and
An object of the present invention is to provide a method for manufacturing a liquid crystal display device that allows the process to be made easier than ever before.

[Summary of the Invention] That is, the present invention provides a method for manufacturing an active matrix type liquid crystal display device in which a plurality of display pixel electrodes are selectively driven by a plurality of TFTs. The method is characterized in that a light blocking film made of metal is formed via an insulating layer, and the surface of this light blocking film is oxidized.

[Embodiments of the invention]

The details of the present invention will be explained below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention. In this embodiment, first, as shown in FIG. 1(a), a gate electrode (2) made of aluminum, for example, is formed on one main surface of a substrate (1), for example a glass substrate, and then a substrate (2) is formed to cover this gate electrode (2). 1
), a gate insulating film (3) made of, for example, silicon nitride is formed to a thickness of about 4,000 yen. Next, as shown in FIG. 1(b), a part-2 corresponding to the gate electrode (2) on the gate insulating film (3), for example, a-8i with a thickness of about 4000
After forming a semiconductor thin film (4) made of ITO, a drain electrode (5) and a source electrode (6) made of, for example, ITO with a thickness of about 100 mm are formed on the 1-gate insulating film (3) so as to be partially in contact with the semiconductor thin film (4). A display pixel electrode (7) is formed integrally therewith. Note that the drain and source electrodes (5), (6)
In order to obtain sufficient ohmic contact, an a-8i film doped with phosphorus may be interposed at the contact portion with the semiconductor thin film (4). The thus formed TPTs and display pixel electrodes (7) are arranged in a matrix on the substrate (1) to obtain a first electrode substrate.

Next (: As shown in FIG. 1(C), an insulating layer (8) made of polyimide and having a thickness of about 1 μm is formed on the first electrode substrate.
This insulating layer (
8) Upper layer: A metal such as aluminum is deposited to a thickness of about 100 OA and etched in a pattern covering the top of the TPT to form a light blocking film (9). Next, Figure 1 (
As shown in d): 2. The surface of the light blocking film (9) is oxidized by, for example, an anodization method, and the oxide film (11 is
After being formed to a thickness of 500A, the insulating layer (8) on top of the display pixel electrode (1) is removed by selective etching.

In this way, a light blocking film (9) is formed on the TFT via the insulating layer (8), and this surface is oxidized. On the other hand, a counter electrode α made of a transparent conductive film is formed on one main surface of a transparent substrate aυ, for example, a glass substrate, and a second electrode substrate is obtained. As shown in FIG. 1(e), the first and second electrode substrates are opposed to each other with a spacer (not shown) interposed therebetween, and the liquid crystal α is sandwiched between them. In this way, a desired liquid crystal display device is obtained.

FIG. 2 is a plan view showing the shape of the pattern of the light blocking film (9) in this example. From the same figure 1:,
The pattern of the light blocking film (9) is in the form of a lattice on the display pixel electrode.

In this embodiment, a column selection line X1 (i=1.2..., m) which is normally used as a data line, and a row selection line Yj (j=1s2..., m) which is normally used as an address line.
A TPT is provided at each intersection of the column selection line Xt and the row selection line Yj. Further, the drain electrode (5) of the TPT is connected to the column selection line Xi, and the gate electrode (2) is connected to the row selection line Yj+2 for each row. The operation of this embodiment is as follows.

That is, when the frame scanning period is T, the row selection line Y'' is sequentially scanned and driven by the address signal, and the TPT is brought into a conductive state sequentially for each row by CTy/n periods. On the other hand, in synchronization with the scanning of row selection line Yj, column selection line Xi
For example, m parallel image signal voltages are supplied. This 1
:Therefore, the signal voltage is sequentially guided to the display pixel electrode (7) row by row, and the liquid crystal (131) held between the opposing electrodes α.
is excited and an image is displayed.

In this embodiment, instead of forming an insulating layer on the light blocking film (9), an oxidation treatment is performed on the light blocking film (9), making the manufacturing process easier than before. Oxide film (C in place of 10: When forming an insulating layer, take into account the step coverage of the light blocking film (9), etc.) If the organic insulating layer is made of polyimide, the thickness is 1 to 2 μm; if the inorganic insulating layer is made of SiN, the thickness is It is necessary to form 4,000 to 5,000 people.C: In this embodiment, the level difference on the substrate (1) is reduced, making the alignment process 42 times easier than in the past.

[Other embodiments of the invention]

FIG. 3 is a diagram showing one step of another embodiment of the present invention,
Components corresponding to those in FIG. 1 are given the same reference numerals. In this example, as shown in FIG. 3, the photo-blocking film (9) is etched into a reverse pattern (: after etching the surface For example, by anodizing, the oxide film α1 is 30%
0 to 500) thickness. Then, the insulating layer (8) on the top of the display pixel electrode is removed by, for example, reactive plasma etching in an oxygen atmosphere using the oxide film α as a mask. This is almost the same as shown, and a desired liquid crystal display device can be obtained.

This embodiment not only has the same effect as the embodiment shown in FIG. 1, but also eliminates the PEP process when removing the insulating layer (8) on the display pixel electrode (7), making the manufacturing process easier. Simplification is possible.

Although the material for the light blocking film (9) is easily oxidized,
In addition to aluminum, titanium, chromium,
Tantalum, tungsten, etc. are good. Also, light blocking film (9)
In addition to anodic formation, the oxidation method may be thermal oxidation or plasma oxidation in an oxygen atmosphere, chemical conversion, boiling in pure water or distilled water, or the like.

〔Effect of the invention〕

As explained above, the method for manufacturing a liquid crystal display device of the present invention simplifies the process compared to the conventional method by forming the insulating layer on the light blocking film in contact with the liquid crystal by oxidation treatment, and improves mass production of the liquid crystal display device. can be increased.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing an example of the shape of a pattern of a light blocking film, and FIG. 3 is a diagram showing another embodiment of the present invention. (1)...Substrate (7)...Display pixel electrode (8)...Insulating layer (9)...Light blocking film (1υ...Transparent substrate (12...Counter electrode aQ...・LCD agent Patent attorney Noriyuki Chika (and 1 other person) No.
1 figure

Claims (2)

[Claims] (1) A first electrode substrate in which thin film transistors and display pixel electrodes are arranged in a matrix on one main surface of the substrate, and a first electrode substrate in which a transparent counter electrode is formed on one main surface of a transparent substrate. In the method for manufacturing a liquid crystal display device comprising a second electrode substrate and a liquid crystal sandwiched between the first and second electrode substrates, a light blocking film made of metal is formed on the thin film transistor with an insulating layer interposed therebetween. and oxidizing the surface of this light blocking film. (2) The method for manufacturing a liquid crystal display device according to claim 1, wherein the metal is made of any one of aluminum, titanium, chromium, tantalum, and tungsten.