JPH0451808B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly to a method for manufacturing a transparent electrode disposed under an alignment film on opposing substrates of a liquid crystal display device. It is.

<Conventional technology> Conventionally, transparent electrodes on cell substrates constituting liquid crystal display devices are mainly made of In-Sn oxide (hereinafter referred to as ITO).
) is used.

The transparent electrode can be manufactured by vacuum evaporation using an electron beam, sputtering, In-
There are chemical conversion methods that involve coating with Sn compounds. Electron beam evaporation, which is classified as the former vacuum evaporation method, uses ITO as a deposition sample and locally heats it with an electron beam to evaporate it and deposit it on a substrate such as glass to form a transparent electrode. A transparent electrode is produced by forming an In film by DC sputtering using In as a target and baking it to form a transparent electrode, or by high-frequency reactive sputtering using ITO as a target.
In the latter chemical conversion method, an In-organic compound is coated on a glass substrate, and then fired to form an oxidized transparent conductive film, which is then used as a transparent electrode.

After coating an alignment film on this transparent electrode, it is heated.
A substrate having a transparent electrode and an alignment film is manufactured. This substrate is inspected and used as a cell substrate for a liquid crystal display device.

<Problems to be Solved by the Invention> When inspecting the electrode pattern, etc. of the above-mentioned substrate, IT, which is a transparent electrode produced by the above-mentioned conventional method,
The disadvantage of the O film is that it is difficult to visually confirm whether or not electrodes are formed on the substrate due to the high transparency of ITO. Therefore, it took time to confirm whether the electrode pattern formation was carried out without any problems.

The present invention provides a method for manufacturing a liquid crystal display device that can solve the above-mentioned conventional problems.

<Example> FIGS. 1 to 5 show cross-sectional views in each step. FIG. 1 shows a process of cleaning a glass substrate 1 to be used. FIG. 2 shows the above glass substrate 1.
In−Sn (90% In, 10% Sn in mol%) film 2
This is a process in which the film is deposited by sputtering to a thickness of 200 to 300 Å. In the step shown in FIG. 3, the In--Sn film 2 from the previous step is patterned into a desired electrode shape using a photoetching method or a screen printed mask. At this time, unnecessary portions of the metal film are removed by etching, but the etching solution used for etching is diluted 0.1 to 0.2 N because it only needs to etch the metal, compared to the conventional case of etching an oxide film. It is sufficient to use a hydrochloric acid aqueous solution of
Compared to minutes, it can be completed in 30 seconds at 30℃. The In--Sn film 2a exhibits a brown hue. In order to use the glass substrate 1 on which the In-Sn film 2a is adhered as a substrate for a liquid crystal cell, a pattern is formed on the glass substrate 1 in the process shown in FIG.
An alignment treatment film 3 is applied on the In-Sn film 2a. Silicon oxide, polyimide resin, etc. are used as the alignment treatment film 3, and in this example, polyimide resin is used. Visually inspect the glass substrate 1 on which the In-Sn film 2a and the alignment treatment film 3 are formed, and
The quality of the Sn film 2a is determined. The process in Figure 5 is
In the annealing step of the substrate 1 coated with the alignment film 3, heating is performed with the temperature range adjusted to 310 to 350° C., and the alignment film 3 is heat-treated. During this annealing process, the previously deposited In-Sn film 2
Perform the oxidation treatment of a. As a result, a transparent electrode 4 made of a heat-treated alignment film 3a and an ITO film is formed.
is fabricated on a glass substrate.

During the annealing process, the area under the alignment film 3
The In-Sn film 2a is oxidized to become an ITO film, which receives oxygen from the atmosphere through small pores (pinholes) in the alignment film 3.
This is considered to be because the alignment film 3 itself receives supply of oxygen contained therein.

The electrode substrate produced by the above process exhibits characteristics of a transmittance of 83% or more and a resistance value of 500Ω/mouth or less in the visible range. As is clear from this example, in the annealing process, the alignment film 3 and In-
The Sn film 2a is heated at the same time, and the In-Sn film 2
Since a is oxidized to become transparent and becomes an ITO film, the above resistance value can be obtained. On the other hand, as in the conventional method, an In-Sn film is formed on a substrate, an electrode pattern is formed by etching, and then a first heating is performed to make the film transparent by oxidation to form an ITO film. In a method in which a second heat treatment is performed after coating the I.
The TO film is further oxidized by secondary heating, which increases its resistance value and tends to cause problems as an electrode, and it is extremely difficult to control heating to prevent this. Ta. It is clear that this problem does not occur in the above embodiment.

Manufacturing processes after the process shown in Figure 5 (sealant printing,
Bonding, liquid crystal injection, etc.) are the same as the conventional method.

<Effects of the Invention> As described above, according to the method for manufacturing a liquid crystal display device of the present invention, the electrode film becomes colored in the electrode pattern inspection, making visual inspection easier, and in the case of etching treatment, the etching target Since the metal oxide is etched using a conventional method, it required 2 minutes at 50℃ using a 4N hydrochloric acid aqueous solution. It takes less time, the operation is simpler, and the adverse effects of the etching solution on the substrate surface can be alleviated.Also, by heating the alignment film and the electrode film, the electrode film under the alignment film can be oxidized. In order to make it transparent, in the conventional method, the electrode film is oxidized and made transparent by heating, and then it is further oxidized by heating during treatment of the alignment film, which tends to lead to an increase in resistance, but this problem can be solved. .

[Brief explanation of the drawing]

1 to 5 are explanatory diagrams showing an embodiment of the method for manufacturing a liquid crystal display device of the present invention. 1... Glass substrate, 2, 2a... In-Sn film,
3, 3a...Alignment treatment film, 4...Transparent electrode.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a liquid crystal display device in which a transparent electrode pattern is formed on at least one surface of opposing substrates and then an alignment treatment film is deposited to obtain a liquid crystal cell substrate, comprising: brown and colored on the surface of
forming a pattern by etching the In-Sn film after depositing; visually inspecting the patterned In-Sn film; and depositing an alignment film on the substrate including the In-Sn film. a step of visually inspecting the patterned In-Sn film; and a step of annealing the In-Sn film and the alignment film to oxidize the In-Sn film to form a transparent electrode. A method of manufacturing a liquid crystal display device, comprising: