JP2867568B2 - Functional multilayer thin film and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a functional multilayer thin film, and in particular, to a functional multilayer thin film including a transparent conductive film and an insulating protective film for protecting the transparent conductive film, and a method for manufacturing the same. According to.

[Conventional technology]

In general, a transparent electrode for a display element, a current-melting glass, and the like, which are one of the functional multilayer thin films, are required to have high translucency and low resistance.

Therefore, conventionally, for example, in a transparent electrode for a display element,
A transparent conductive film as an electrode is laminated on a thin glass substrate, and the transparent conductive film is covered from above on the transparent conductive film.

In this case, ITO that can obtain a relatively low resistance value is often used as the transparent conductive film. This ITO is In
₅ to 10 wt% of SnO ₂ is added to impart conductivity to ₂ O ₃ , and its crystal is considered to be the same as In ₂ O _{3 as the} main component.

Further, as the insulating protective film, SiO ₂ is generally used from the viewpoints of high translucency, low bending ratio, and low cost.

These two thin films are sequentially laminated on a glass substrate using a general method of forming a thin film in a vacuum, such as sputtering or vapor deposition.

In addition, as a conventional technology of such a functional multilayer thin film,
For example, JP-A-63-57757 (Japanese Patent Application No. 61-202189)
No.).

[Problems to be solved by the invention]

However, in such a functional multilayer thin film, as shown in Table 1, both the crystal form and the lattice constant of ITO (side, In ₂ O ₃ ) of the transparent conductive film and SiO _{2 of the} insulating protective film are large. Because of the difference, when both were laminated as a thin film, the interface was poor in conformity and the adhesion was poor.

For this reason, the two thin films are easily peeled off at the interface, and thus lacked abrasion resistance.

Therefore, an object of the present invention is to improve the adaptability of both thin films and improve the adhesion between the two thin films.

[Means for solving the problem]

Therefore, the functional multilayer thin film of the present invention is composed of a transparent conductive film composed of an ITO thin film containing tin oxide laminated on a glass substrate and an insulating protective film composed of a silicon oxide thin film laminated on the transparent conductive film and covering the surface thereof. In the functional multilayer thin film constituted by the film, the surface of the ITO thin film is a composition change layer in which the addition amount of tin oxide gradually increases toward the surface side, and further, the transparent conductive film and the insulating protective film A diffusion layer between the ITO thin film and the silicon oxide thin film is provided at the boundary between the thin film and the silicon oxide thin film.

Further, the method for producing a functional multilayer thin film of the present invention comprises, on a glass substrate, a transparent conductive film and an insulating protective film covering the transparent conductive film by a physical thin film forming method such as vacuum deposition, ion plating, and sputtering. A method for producing a functional multilayer thin film to be laminated, comprising the steps of:
While laminating the ITO thin film, the amount of tin oxide added was gradually increased on the surface of the ITO thin film, and the composition change layer was continuously laminated to form a transparent conductive film. Are laminated to form a multilayer film as an insulating protective film, and then a heat treatment is performed to form a diffusion layer at a boundary between the transparent conductive film and the insulating protective film.

[Action]

According to the above-described means, the surface of the ITO thin film, which is a transparent conductive film, is a composition change layer in which tin oxide is gradually increased toward the surface side, so that it is compatible with the silicon oxide thin film, which is an insulating protective film. Further, since the diffusion layer of the ITO thin film and the silicon oxide thin film is formed by heat treatment at the boundary between the transparent conductive film and the insulating protective film, the adhesion at the boundary between the two thin films is improved.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a sectional view of a functional multilayer thin film showing one embodiment of the present invention.

Then, as shown in FIG. 1, the functional multilayer thin film 1
ITO thin film 31 on glass substrate 2 containing indium oxide (In ₂ O ₃ ) as a main component and tin oxide (SnO ₂ ) added at 5 to 10 wt%
Then, the transparent conductive film 3 composed of the composition change layer 32 in which the addition amount of tin oxide gradually increases toward the surface side and finally becomes 100 wt% tin oxide is formed on the surface of the ITO thin film 31. The transparent conductive film 3 is laminated on the transparent conductive film 3.
An insulating protective film 4 mainly composed of silicon oxide (SiO ₂ ) is laminated, and an ITO thin film 31 and a silicon oxide are formed on the boundary between the composition change layer 32 of the transparent conductive film 3 and the insulating protective film 4. It has a thin-film diffusion layer 5.

Next, a method of manufacturing the functional multilayer thin film 1 configured as described above will be described.

First, a multi-source sputtering device
Using In ₂ O ₃ and SnO ₂ , the glass substrate 2 was heated to 300 ° C. in an Ar atmosphere at a degree of vacuum of 5.0 × 10 ^-1 Pa, and the high frequency power was 500 W for the In ₂ O ₃ target and the SnO ₂ target was Is high frequency power 50
W was applied. As a result, about 5 wt% on the glass substrate 2
An In ₂ O ₃ thin film (ITO thin film) 31 to which SnO ₂ was added was formed.

Further, after the ITO thin film 31 is formed to a thickness of 300 nm, the high-frequency power applied to the In ₂ O ₃ target is continuously reduced from 500 W to 0 W.
W is gradually changed, and by gradually changing the high frequency power applied to the SnO ₂ target from 50 W to 1000 W, the addition amount of SnO ₂ is gradually increased, and finally SnO ₂ 100w
A composition change layer 32 having a concentration of t% was formed, and a transparent conductive film 3 was formed. The high-frequency power applied to the SnO ₂ target is finally 1000 W, and the high-frequency power applied to the In ₂ O ₃ target is 500 W
The reason for the increase is that the sputtering rate of SnO ₂ is as low as about half of the sputtering rate of In ₂ O ₃ .

Then, on this composition change layer 32, using SiO ₂ as a target, the glass substrate 2 was placed at 300 ° C. in an Ar atmosphere, and the degree of vacuum = 5.0.
The insulating protection film 4 of SiO ₂ was formed by sputtering under the conditions of × 10 ^-1 Pa and an applied high-frequency power of 500 W. The thickness of the insulating protective film 4 was 180 nm.

After that, in an O ₂ atmosphere, the degree of vacuum = 7.0 × 10 ⁻² Pa,
The diffusion layer 5 was formed at the boundary between the composition change layer 32 of the transparent conductive film 3 and the insulating protective film 4 by performing a heat treatment for one hour under the condition of the atmosphere temperature of 500 ° C.

As a comparative example, a functional multilayer thin film (hereinafter, referred to as Comparative Example 1) laminated under the same steps and the same sputtering conditions as those of the above-described embodiment except that the step of the heat treatment was omitted, and simply formed on the ITO thin film Functional multilayer thin film laminated with SiO ₂ and not subjected to heat treatment (hereinafter referred to as Comparative Example 2)
Was manufactured. Next, results of a Taber abrasion test of this example and Comparative Examples 1 and 2 will be described with reference to FIGS. In addition, in this Taber abrasion test,
The wear wheel used CS-10F, the load was 500 g, and the rotation was performed up to 1000 revolutions.

FIG. 2 is a diagram showing a change characteristic of the haze value after the Taber abrasion test when the thickness of the composition change layer 32 of the transparent conductive film 3 of this embodiment is changed. This shows the change in the haze value.

The haze value is an index indicating wear resistance, and the smaller the haze value is, the smaller the haze value is.

As can be seen from FIG. 2, as the thickness of the composition change layer 32 increases, the haze value decreases and becomes constant when the thickness is 20 nm or more. From this, the thickness of the composition change layer 32 is 20
nm or more is preferred. However, even at this thickness, the haze value is not less than 2% of the target, and the wear resistance is insufficient.

FIG. 3 is a graph showing a change in base value after a Taber abrasion test when the heat treatment conditions of the functional multilayer thin film of this example were changed.
The heating time was changed to 00 ° C., 600 ° C., and 700 ° C., and the change in the haze was plotted on the abscissa.

As can be seen from FIG. 3, the heating time was changed to the ambient temperature.
By setting the temperature at 400 ° C. for about 80 minutes and the temperature at 700 ° C. for about 30 minutes, the haze value becomes 2% or less of the target, and it can be seen that sufficient abrasion resistance can be secured. This is because the diffusion layer 5 was formed near the interface between the transparent conductive film 3 and the insulating protective film 4 by the heat treatment, and peeling was prevented.

When the ambient temperature is 300 ° C. or lower, the diffusion layer 5 is hardly formed, and when the ambient temperature is 800 ° C. or higher, the glass substrate 2 is easily melted and damaged. It is preferable to set.

FIG. 4 is a graph showing the change in the haze value between the functional multilayer thin film of this embodiment and Comparative Examples 1 and 2 according to the increase in the number of Taber abrasions. The change of the haze value with the number of Taber abrasions on the horizontal axis is shown.

As can be seen from FIG. 4, the haze value of the multilayer thin film of this example was 2% or less even after 1000 rotations of the Taber abrasion frequency.
It can be seen that the abrasion resistance of the functional multilayer thin film of this example is significantly improved, as compared with a value exceeding 11 at 1000 rotations. In Comparative Example 1, although the wear resistance was improved as compared with Comparative Example 2, the wear resistance was still insufficient.

In the case of this embodiment, the sheet resistance of the transparent conductive film 3 formed by the ITO thin film 31 and the composition change layer 32 is about 10 Ω / □.
Thus, it can be sufficiently applied to a transparent electrode for a display element and the like, which require high translucency and low resistance.

In the above embodiments, the composition change layer in which tin oxide finally becomes 100 wt% has been described as an example. However, the present invention is not limited to this, and the compatibility with the silicon oxide forming the insulating protective film is good. Any ratio may be used.

Further, the method of manufacturing the functional multilayer thin film by sputtering has been described as an example, but the present invention is not limited to this, and the functional multilayer thin film may be manufactured by another physical thin film forming method such as ion plating.

〔The invention's effect〕

According to the present invention, as described above, the surface of an ITO thin film, which is a transparent conductive film, is a composition change layer in which tin oxide is gradually increased toward the surface, and an insulating protective film formed of a silicon oxide thin film is formed thereon. Since the two thin films are stacked, the boundary between the two thin films is made of a combination of materials having the same crystal form of tin oxide and silicon oxide and a similar lattice constant, so that the compatibility between the transparent conductive film and the insulating protective film can be improved. .

Furthermore, since a diffusion layer of the ITO thin film and the silicon oxide thin film is formed at the boundary between the transparent conductive film and the insulating protective film by heat treatment, the adhesion between the two thin films can be greatly improved, and the thin films are separated. Can be prevented, and the wear resistance can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a functional multilayer thin film showing one embodiment of the present invention, and FIG. 2 is a haze value after a Taber abrasion test when the thickness of the composition change layer of the transparent conductive film in FIG. FIG. 3 is a change characteristic diagram of the haze value after the Taber abrasion test of the functional multilayer thin film in FIG. 1 when the heat treatment condition is changed, and FIG. 4 is a graph according to the increase in the number of Taber abrasion. Functional multilayer thin film in FIG. 1 and Comparative Examples 1 and 2
6 is a change characteristic diagram of the haze value of FIG. DESCRIPTION OF SYMBOLS 1 ... Functional multilayer thin film 3 ... Transparent conductive film 32 ... Composition change layer 4 ... Insulating protective film 5 ... Diffusion layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C03C 15/00-23/00

Claims (2)

(57) [Claims] 1. A transparent conductive film composed of an ITO thin film containing tin oxide laminated on a glass substrate, and an insulating protective film composed of a silicon oxide thin film laminated on the transparent conductive film and covering the surface thereof. In the functional multilayer thin film, the surface of the ITO thin film is a composition change layer in which the addition amount of tin oxide gradually increases toward the surface side, and further, a boundary portion between the transparent conductive film and the insulating protective film. A functional multilayer thin film comprising a diffusion layer of the ITO thin film and the silicon oxide thin film. 2. A method for producing a functional multilayer thin film in which a transparent conductive film and an insulating protective film covering the transparent conductive film are laminated on a glass substrate by a physical thin film forming method such as vacuum deposition, ion plating, and sputtering. On the glass substrate surface, the IT
While laminating the O thin film, the amount of tin oxide added is gradually increased on the surface of the ITO thin film, and the composition change layer is continuously laminated to form a transparent conductive film. Are laminated to form a multilayer film as an insulating protective film, and then heat-treated to form a diffusion layer at a boundary between the transparent conductive film and the insulating protective film. Manufacturing method.