JPH0658476B2 - Method for manufacturing substrate for liquid crystal display device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for manufacturing a substrate for forming a pattern display electrode, and more particularly to a method for manufacturing a liquid crystal display device using a plastic film or a plastic substrate for this substrate.

BACKGROUND OF THE INVENTION Conventionally, a liquid crystal display element has been constructed by interposing a liquid crystal between upper and lower two glass substrates each having a counter electrode formed on an inner surface thereof and sealing a peripheral portion with a sealing material. In recent years, a plastic liquid crystal display element using a plastic film substrate instead of a glass substrate has been proposed, for example, in Japanese Patent Laid-Open No. 53-68099.

A liquid crystal display device using this type of plastic film substrate has a low heat resistance as a method for forming electrodes on the plastic film substrate.
A vapor deposition method using B (electron beam), a vapor deposition method using resistance heating, or a sputtering method is used. Particularly, in the sputtering method, since radiant heat is small, it is possible to form a transparent and conductive thin film on a film substrate at a low temperature. When a thin film of this type is formed on a film substrate by using a low temperature sputtering method, it can be roughly classified into two types. One is I _n2 O ₃ , S _n O ₂
A metal oxide etc. as Tagetsuto, a method of forming a A _r (hereinafter referred to as ITO film) transparent conductive film in the row of connexion film on a substrate Supatsutaringu in (argon) atmosphere, I _n another method the -S _n alloy subjected to Supatsutaringu in a mixed atmosphere of a _r and O ₂ (oxygen), and a method of forming an ITO film is deposited on the film substrate to generate a metal oxide in Supatsutaringu. The ITO film thus formed is subjected to etching or the like in a later step to form a desired pattern display electrode, an electrode terminal, and a translucent electrode such as a lead electrode for electrically connecting the two. .

However, although the ITO film formed by the method described above is not completely crystallized, it can be crystallized by firing at a high temperature of about 400 to 500 ° C when formed on a conventional glass substrate or the like. However, in the case of a film substrate on which an ITO film is formed, it is impossible to perform high-temperature baking at about 400 ° C except for a special polyimide film, so the ITO film is acid and alkaline. In any of the above cases, it dissolves easily and its chemical resistance is extremely lower than that of the crystallized ITO film. In other words, the difficulty in using the plastic substrate was that it was extremely difficult to crystallize the ITO film by heating.

As an improvement on such a problem, Japanese Patent Publication No. 59-412
As proposed in Japanese Patent No. 41, a method of crystallizing an ITO film by raising the film substrate temperature to about 170 ° C. has been proposed. However, even in this method, since the film substrate is formed of an organic material, the heating temperature is sufficiently high even at about 170 ° C., and in extreme cases, the film substrate itself is largely deformed or shrunk, or the material is Therefore, the melting point is exceeded and the function as an electrode substrate cannot be obtained.

[Object of the Invention]

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to form a crystallized ITO film on a film substrate without impairing the function as an electrode substrate. An object of the present invention is to provide a method for manufacturing a liquid crystal display device capable of manufacturing the liquid crystal display device. Another object of the present invention is to provide a method of manufacturing a liquid crystal display device capable of forming an ITO film having excellent chemical resistance on a film substrate.

[Outline of Invention]

In order to achieve such an object, the present invention provides an amorphous I film on a substrate for a liquid crystal display device by a low temperature sputtering method.
By irradiating ultraviolet rays after forming the TO film, I
The TO film is crystallized.

Example of Invention

With 10 wt% of tin oxide as Tagetsuto of <Comparative Example> Supatsutaringu indium oxide containing _{(SnO 2) (I n2 O} 3), the temperature of the substrate so as not exceed 40 ℃, A _r (argon) atmosphere And perform spantering. A sufficient amount of O ₂ (oxygen) is added from the outside during sputtering to form a film with a sheet resistance of the ITO film formed on the substrate of at least 300Ω / b and a transmittance of 85-90% (ITO film only). To do. The film thickness at this time is 300 to 400Å. For the substrate formed by the above method, (1) no treatment, (2) 170 ° C, 24 hours heating, (3) UV light irradiation 40 ° C, 20 minutes (however, 365 nm, 3 nm
(0 mw), and acid resistance was examined using an aqueous HC solution. The results are shown in Table 1 (HC liquid is HC ...
Using those _{1, H 2 O ···· 5,} HNO 3 ···· 0.08% mixing ratio).

The acid resistance was evaluated by the time until the resistance value became infinite.
In the experiment of this comparative example, no change in acid resistance was observed by the ultraviolet irradiation treatment performed under the condition (3). The acid resistance of the untreated crystal is low because the formed ITO film is not crystallized. It is considered that in the treatment (2), since the ITO film was crystallized due to the heating, the acid resistance was improved.

<Example> As compared with the sputtering condition described as a comparative example, the oxygen concentration in the atmosphere is lowered, and conditions are set such that the formed ITO film becomes a low oxide. Other conditions are the same as in the comparative example. In the present specification, the low oxide of indium refers to one represented by the following general formula.

InxOY (0 <Y / X <1.5) Indium oxide has a general formula of In ₂ O ₃ , and when the ratio of indium to oxygen is more than that of the general formula In ₂ O ₃ of 2: 3, Alternatively, the case where the amount of oxygen is small is shown. The characteristic of the formed ITO film is 60-70 in resistance value.
KΩ / B, transmittance 40 to 50%.

Table 2 shows the results of performing the same treatments (1), (2), and (3) as those shown in the comparative example and further performing the same evaluation.

Unlike the case of the comparative example, the ITO film irradiated with UV light also shows the same tendency as the one subjected to the heat treatment, and the acid resistance is improved. By irradiating with UV light, it is possible to reduce the resistance of the nesa and further improve the acid resistance without increasing the temperature of the substrate. Although there are many unclear points regarding each condition such as UV light irradiation intensity and time, heating to the heat-resistant temperature of the substrate film will bring about some effect in a shorter time.
Further, the effect of the nesa is the same whether it is formed by a sputter or by EB (electron beam) vapor deposition. Furthermore, there is no difference (metal or oxide) due to the target used during sputtering.

〔The invention's effect〕

As described above, according to the present invention, a crystallized transparent conductive film can be obtained without deforming the substrate by irradiating ultraviolet rays after forming the transparent conductive film by low temperature sputtering on the substrate. At the same time, the chemical resistance can be improved, and an extremely excellent effect such as the realization of a liquid crystal display device with high quality and reliability can be obtained.

Claims (1)

[Claims] 1. A method of manufacturing a substrate for a liquid crystal display element, which is formed by depositing an electrode made of a transparent conductive film, wherein the transparent conductive film is formed on the substrate for a liquid crystal display element by a low oxide of indium (InxOy, O < A method for manufacturing a substrate for a liquid crystal display element, which is characterized in that Y / X <1.5) is formed by sputtering, and then the transparent conductive film is crystallized by irradiation with ultraviolet rays.