JPH0780692B2 - Conductive glass and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Prior Art] The present invention relates to a conductive glass with an alkali barrier film which prevents alkali ions from diffusing from a glass substrate of alkali-containing glass.

The glass plate as a transparent material is chemically stable, has excellent surface hardness, withstands high temperatures of about 500 ° C to 700 ° C, and has excellent electrical insulation and optical properties. Not only as a window glass material for aircraft, but also as an optical component, an electrical component, an electronic component, and the like. In particular,
Recently, an electrically conductive glass plate having an electrically conductive coating formed on the surface of a glass plate has been used as a display element such as a liquid crystal element, an electrochromic element, an electroluminescent element, or an amorphous solar cell substrate. As the glass substrate for these conductive glass plates, soda lime silica glass plate, which is the most widely used and inexpensive, tends to be used, but this soda lime silica glass plate is compositionally about 10 to 20 wt%. Since it contains alkali components such as sodium and potassium, it has a drawback that the performance of the coated conductive film deteriorates due to the diffusion of alkali ions from the glass substrate to the surface after long-term use. For example, white turbidity may occur in the conductive film of the conductive glass plate, the transparency may decrease, the resistance value of the conductive film may increase, or the chemical and physical durability may decrease.

That is, in the liquid crystal display element, the alkali that diffuses from the glass causes a redox reaction on the surface of the display electrode to change the quality of the transparent electrode material, the indium oxide film (ITO film) or the tin oxide film (nesa film). The liquid crystal itself also undergoes electrolysis and deteriorates. Even in the electrochromic device, the electrode is worn out for the same reason, and the durability of the electrochromic material such as tungsten oxide or molybdenum oxide is deteriorated to deteriorate the device. Also in the case of an electroluminescent device, the alkali that has emerged from the glass surface due to diffusion penetrates the conductive film and enters the phosphor material to change the luminous efficiency and the emission color. Furthermore, in the case of an amorphous solar cell, the resistance value of the conductive film increases and the photoelectric conversion efficiency decreases significantly, and sometimes the alkali that penetrates through the electrode diffuses into the amorphous silicon to improve the conversion efficiency. It is said that there is a risk of lowering it.

Alternatively, in alkali-containing glass such as soda lime silica glass, alkali ions tend to move during high temperature treatment, and diffusion of alkali ions during high temperature treatment during production of conductive glass or various coated glasses. As a result, there is a drawback that the performance of the conductive film or various coated films is deteriorated.

A typical solution to this drawback is to form a thin film on the surface of ordinary soda lime silica glass to prevent alkali diffusion, and a silica film is generally used. The reason why a silicon oxide film (eg, SiO ₂ film) is used to prevent alkali diffusion is that the film is amorphous, and when another thin film, such as a conductive film, is formed on top of this, the same film as that formed on glass is formed. What can be done and the refractive index of the silicon oxide film is slightly lower than glass, but close to glass,
In addition, the transparency of glass is not impaired because it is transparent to a wider range of light than that of ordinary plate glass.

[Problems to be Solved by the Invention] However, while the conductive film formed on the alkali barrier film is formed by the direct current sputtering method capable of forming a uniform film over a large area at high speed, silicon oxide is used. If you try to form a film by a DC sputtering method using a Si target, the surface of the Si target will be oxidized during sputtering and the electrical conductivity will decrease, making it impossible to maintain stable sputtering. Since the film could not be formed, the film was formed by the RF sputtering method or the CVD method using the oxide target.

Therefore, the RF of the silicon dioxide film is different from the method of forming the conductive film.
Since it is necessary to tune the sputtering and control the sputtering atmosphere, or to form a film by the CVD method using another device, it is not possible to form a silicon dioxide film continuously with the conductive film in-line. It had the problem of being inferior in sex.

[Means for Solving the Problems] The present invention has been made based on the above problems by finding a new alkali barrier film that can be formed by a direct current sputtering method. An alkali barrier film for suppressing alkali diffusion, and a conductive glass in which a conductive film is sequentially laminated, wherein the alkali barrier film is formed by a DC sputtering method, and at least one of Zr, Hf, Nb, Sn, and La is formed. Seed metal and Si
An amorphous film containing an oxide containing as a main component, wherein the content ratio of Si atoms in the film is
The present invention provides an electrically conductive glass, characterized in that Si is 5 atoms or more and 96 atoms or less, and a method for producing the same.

The alkali barrier film of the present invention is a film whose main component is an alkali barrier film whose main component is an oxide containing at least one of Zr, Hf, Nb, Sn and La and Si. Further, the alkali barrier film of the present invention may contain at least one of Ti, Ta, Mo, W and Cr, if desired.

As the composition of the alkali barrier film of the present invention, Si is contained at a ratio of 5 atoms or more with respect to the total amount of 95 atoms of metals such as Zr and Hf. This is because if the Si content is less than this proportion, the film becomes crystalline and the alkali barrier ability is significantly reduced. Further, Si is contained at a ratio of 96 atoms or less to a total amount of 4 atoms of metals such as Zr. If the Si content exceeds this ratio, the target cannot be stably deposited by the DC sputtering method due to the surface oxidation of the target. That is, the alkali barrier film in the present invention contains at least one metal selected from Zr, Hf, Nb, Sn and La and Si, and
The content ratio of Si atoms is Si based on the sum of the metal and Si.
Is 5 at% or more and 96 at% or less.

The refractive index of the alkali barrier film of the present invention can be freely adjusted by its composition. Table 1 shows the change in refractive index depending on the composition of the alkali barrier film when Zr is used as the metal.
Shown in.

Therefore, in the case of conductive glass as a transparent electrode plate of a display element or the like having a transparent electrode such as an ITO film (tin-containing indium oxide film) as a conductive film, the composition of the alkali barrier film of the present invention is If the refractive index is the same as that of the transparent electrode, the refractive index of the portion where the transparent electrode pattern is formed on the alkali barrier film and the portion where only the alkali barrier film is formed without forming the transparent electrode are Since there is no difference, the transparent electrode pattern is inconspicuous, and the so-called "bone-like" phenomenon of the transparent electrode pattern can be prevented. For example, in a conductive glass having a structure of glass plate / alkali barrier film / ITO film made of oxide containing Zr and Si, ITO
According to the refractive index of the film of about 1.9, from Table 1, Zr: Si = 70: 30 may be set. Alternatively, in the manufacture of display elements, etc., in terms of alignment, when it is desired to see the transparent electrode pattern, it is appropriate to set the refractive index different from that of the ITO film, and increase the proportion of Si. It can also have a low refractive index. As described above, the composition of the alkali barrier film of the present invention can be appropriately selected according to the refractive index of the conductive film formed thereon.

The thickness of the alkali barrier film of the present invention is preferably 50 Å or more so that a sufficient alkali barrier ability is exhibited. Of these, the range of 100Å to 5000Å is the most practical.

Further, as the glass applicable to the conductive glass of the present invention, not only the most widely used soda lime silica glass containing 10 to 20 wt% of Na or K, but also various other alkali-containing glasses can be cited.

In the conductive glass of the present invention, the conductive film formed on the alkali barrier film is a transparent conductive film such as an ITO film, a SnO ₂ film doped with F or Sb, or a ZnO film doped with Al. There is no particular limitation as long as it is a conductive film such as a conductive oxide film or a conductive metal film such as Ag or Au, which may be deteriorated by alkali ions.

Example 1 An ordinary glass plate (soda / lime silica glass plate) containing 15% of 10 cm × 10 cm × 3 mm alkali component R ₂ O (R: Na, K) was thoroughly washed with a detergent, washed with water and dried. did. This glass plate is placed in the vacuum chamber of the sputtering system and the inside of the chamber is set to 1 × 10 ^-5.
After exhausting to Torr, a target composed of Zr and Si (Zr: S
i = 10: 90) was subjected to DC sputtering in a mixed gas of 2 × 10 ⁻³ Torr of argon and oxygen to form a Zr _0.1 Si _0.9 O ₂ film of about 1000 Å.

Comparative Example 1 CVD using SiH ₄ and O ₂ gas on the same glass plate as in Example 1
A SiO ₂ film of 1000 Å was formed by the method.

The product of Example 1 and the product of Comparative Example 1 were each brought into contact with pure water to obtain 90
After keeping at ℃ for 24 hours, the amount of Na ⁺ eluted in pure water was measured to examine the alkali barrier property.
It was 0.60 μg / cm ² , and the product of Comparative Example 1 was 0.61 μg / cm ² .
Further, the product of Example 1 and the product of Comparative Example 1 were each washed with 5% NaOH, and then contacted with pure water at room temperature for 24 hours to elute the amount of Na ⁺ eluted in the pure water (the Na adsorbed during the cleaning). The amount of ⁺ ) was measured to check the alkali adsorptivity, and it was 0.13 μg / cm in Example 1 product.
² , the product of Comparative Example 1 was 0.14 μg / cm ² . From this,
It was found that the product of Example 1 has substantially the same characteristics as the comparative example.

Example 2 In the same manner as in Example 1, a Zr _0.1 Si _0.9 O ₂ film was formed to a thickness of about 200 Å.

ZrSi ₂ target as in Example 3 target (Zr: Si = 1: 2 ) with the other in the same manner as in Example 1, about a Zr _0.33 Si _0.66 O ₂ film
200Å formed.

Example 4 In the same manner as in Example 3, a Zr _0.33 Si _0.66 O ₂ film was formed to a thickness of about 500 Å.

Each of Examples 2 to 4 was contacted with pure water to obtain 85
After storing at 24 ° C. for 24 hours, the alkali barrier property and alkali adsorptivity were measured and the results are shown in Table 2.

For each of the products of Examples 1 to 4, after forming each alkali barrier film by a DC sputtering method, an ITO film was continuously formed on the alkali barrier film by a DC sputtering method, and then stored at 90 ° C. for 24 hours. There was no change in the appearance of the ITO film.

Further, even when Hf, Nb, Sn, and La were used instead of Zr, the same results as in the above-mentioned examples were shown, and the alkali barrier performance was confirmed.

[Operation] In the present invention, in a target made of metal such as Zr and Hf and Si, Zr, Ti, Ta, Hf, Mo, W, Nb, La and Cr are mostly silicon compounds, and Sn is Si. -Exists as Sn alloy, Si
Less active than oxygen as compared to
Since it works to suppress the decrease in conductivity due to surface oxidation of the target during DC sputtering, it is considered that the film can be stably formed by the DC sputtering method.

EFFECT OF THE INVENTION Since the alkali barrier film of the conductive glass of the present invention can be formed by the DC sputtering method, a uniform film over a large area can be stably formed at high speed and provided. This is a great advantage especially in terms of productivity because the alkali barrier film and the conductive film can be continuously formed by an in-line method when the conductive film formed on the alkali barrier film is formed by the DC sputtering method. .

The conductive glass with an alkali barrier film of the present invention is particularly suitable as a liquid crystal element, an electrochromic element, a display element such as an electroluminescent element or an alkali diffusion preventive film of a conductive glass used for an amorphous solar cell substrate or the like,
As can be seen from Table 1, it also has heat resistance, and is stable and does not deteriorate even in the manufacturing process of such display elements and solar cells and in various environmental conditions thereafter. Of course, in addition to these, it has a conductive coating on glass plates for automobiles, aircraft, railway vehicles and other various transportation vehicles, construction, various devices, optical parts, electric parts, electronic parts, and various other functions. It can be usefully applied to a base coat when forming a coating.

Further, when the periphery of a liquid crystal cell or the like is sealed, if the alkali barrier film of the present invention is interposed between the sealant and glass,
It is also possible to prevent peeling of the sealant due to alkali.

Further, since the alkali barrier film of the present invention can be made to have a desired refractive index by changing the ratio of metal such as Zr and Si, it can be widely used for the above various uses.

Further, since the alkali barrier film of the present invention has a low alkali adsorption property, it can be sufficiently used even if there is a step of washing with an alkali-containing liquid in the production of liquid crystal cells and the like.

Claims (4)

[Claims] 1. A conductive glass comprising an alkali-containing glass, an alkali barrier film for suppressing alkali diffusion from the glass, and a conductive film, which are sequentially laminated on the surface of the alkali-containing glass, wherein the alkali barrier film is formed by a DC sputtering method. An amorphous film which is formed into a film and contains an oxide containing at least one metal selected from Zr, Hf, Nb, Sn and La as the main component, and the content of Si atoms in the film is Metal and Si
Si is 5 atomic% or more and 96 atomic% or less with respect to the sum of the above. 2. The conductive glass according to claim 1, wherein the alkali barrier film contains at least one of Ti, Ta, Mo, W and Cr. 3. Zr, Hf, Nb, S on the surface of alkali-containing glass
contains at least one metal of n and La and Si, and
The content ratio of Si atoms is Si based on the sum of the metal and Si.
A method for producing a conductive glass, which comprises forming an amorphous alkali barrier film containing an oxide whose main content is 5 at% or more and 96 at% or less as a main component by a DC sputtering method, and then forming a conductive film. 4. The method for producing an electrically conductive glass according to claim 3, wherein the electrically conductive film is formed continuously with the alkali barrier film by a DC sputtering method.