KR20230146996A - Target and blackening layer - Google Patents

Abstract

The present invention has a composition expressed as Cu _a Ni _b Co _c , a represents the proportion of Cu in at%, b represents the proportion of Ni in at%, c represents the proportion of Co in at%, a+b+c= A sputtering target of 100, 0.30≤a/(a+b+c)≤0.70, 10≤b≤65, 0.1≤c, and a metal oxide with a composition of (Cu _a Ni _b Co _c ) _100-x O _x , a represents the proportion of Cu in at%, b represents the proportion of Ni in at%, c represents the proportion of Co in at%, x represents the proportion of O in at%, a+b+c=100, 0.30≤ It relates to a blackening film characterized by a/(a+b+c)≤0.70, 10≤b≤65, 0.1≤c, 30≤x≤50.

Description

Target and blackening layer{TARGET AND BLACKENING LAYER}

This invention relates to a target for sputtering and a blackening film that can be suitably formed using this target.

A touch panel is a device that combines the two functions of display and input by superimposing a sensor (touch panel sensor) for detecting touch operations on the upper surface of a display device (display device) represented by a liquid crystal panel. In this touch panel, when an operator touches a display on the screen, information on the operated position is output to the outside as a signal, and the external device performs an appropriate operation desired by the operator based on the position information of the manipulated position.

Conventionally, transparent ITO (Indium Tin Oxide) electrodes have been used as electrodes in touch panel sensors. However, ITO has a high specific resistance and is also inferior in bendability, so it has recently been used as an electrode for touch panel sensors. It has the problem of not being able to sufficiently respond to the larger or curved panel.

For this reason, metal mesh wiring made by processing Cu or Al into a mesh shape, which has better resistivity and bendability than ITO, is beginning to be used. In the case of a metal electrode using this metal wire, since the metal wire is opaque and has a metallic luster, light from the outside strikes the metal wire and is reflected, and the visibility of the display portion is reduced due to the reflected light, which is a problem. As a means of solving this problem, it has been proposed to form a blackening film as a reflection reduction film on the surface of the metal wire (see Patent Documents 1 and 2 below).

Japanese Patent Publication No. 2016-216795 Japanese Patent Publication No. 2016-216797

However, the blackening film as a reflection reduction film is expected to expand in application in vehicle applications in the future, and environmental test characteristics that prevent the film surface from discoloring even under high temperature and high humidity are required. For example, the blackening film described in Patent Document 1 is made of an oxide of CuNiW alloy, and the blackening film described in Patent Document 2 is made of an oxide of CuNiMo alloy. However, these known blackening films have not been able to obtain sufficient environmental resistance test characteristics.

Against the background of the above circumstances, the present invention is to provide a blackening film with low reflectance and environmental test characteristics that are difficult to discolor even under high temperature and high humidity, and a sputtering film suitable for forming this blackening film. This was done with the purpose of providing a target.

The present inventors have conducted extensive studies to solve the above problems and have found that, by additionally containing a predetermined amount of Ni and Co in the blackening film containing the oxide of Cu, the environmental test characteristics that are difficult to discolor even under high temperature and high humidity are improved. found what was achieved. The present invention has been made based on this recognition.

And the blackening film of the present invention is made of a metal oxide whose composition is expressed as (Cu _a Ni _b Co _c ) _100-x O _x , where a represents the proportion of Cu in at%, and b represents the proportion of Ni at Expressed in %, c represents the proportion of Co in at%, and x represents the proportion of O in at%,

It is characterized by a+b+c=100, 0.30≤a/(a+b+c)≤0.70, 10≤b≤65, 0.1≤c, 30≤x≤50.

According to the present invention defined in this way, it is possible to produce a blackening film that has low reflectance and has environmental test characteristics that are difficult to discolor even under high temperature and high humidity.

Here, if x is 30 ≤

In addition, if x is 40≤x≤50, a blackening film can be obtained that has low reflectivity and environmental test characteristics as well as suppressed electrical resistivity to a low level.

In addition, the target of the present invention is a target for sputtering and has a composition expressed as Cu _a Ni _b Co _c , where a represents the proportion of Cu in at%, the b represents the proportion of Ni in at%, and the c represents the ratio of Co in at%,

It is characterized by a+b+c=100, 0.30≤a/(a+b+c)≤0.70, 10≤b≤65, 0.1≤c.

By using the target of the present invention defined in this way, a blackening film with low reflectivity and environmental test characteristics can be suitably formed by reactive sputtering using a sputtering device.

FIG. 1(A) is a diagram showing a laminate provided with a blackening film according to an embodiment of the present invention, and FIG. 1(B) is a diagram showing an example of another form of the same laminate.
Figure 2 is a diagram showing another example of a dynamic layer body.
Figure 3 is an explanatory diagram of an environmental resistance test.

(Form for carrying out the invention)

Next, embodiments of the present invention will be described in detail.

<1. Laminate>

In Fig. 1, 10A represents an example of a laminate provided with a blackening film of one embodiment of the present invention. In the same figure, 12 is a transparent substrate, and on one side of this substrate 12 (the upper surface in the drawing), a metal layer 14 to form an electrode is laminated in a film shape over the entire surface of the substrate 12. And a blackening film 16 as a reflection reduction film is laminated on the surface of this metal layer 14 opposite to the base material 12, that is, the upper surface in the figure. This blackening film 16 is also laminated in a film shape over the entire surface of the metal layer 14.

The transparent substrate 12 may be glass such as soda lime glass, and may also be made of polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polycarbonate (PC), or polymethyl methane. Resin materials such as crylate (PMMA) and polyimide (PI) may also be used. As the resin material, polyethylene terephthalate (PET) is preferable.

The metal layer 14 is preferably highly conductive with an electrical resistivity of 8.0 μΩ·cm or less, and pure Cu, Cu alloy, pure Al, Al alloy, etc. can be used as such materials.

The blackening film 16 is laminated on the upper surface of the metal layer 14 in the drawing. The blackening film 16 is a layer aimed at preventing light from the outside from hitting the metal wire (metal layer) and being reflected, thereby reducing the visibility of the display portion due to the reflected light. The blackening film 16 has a light reflectance of less than 20%, Preferably, it is suppressed to less than 15%. This blackening film 16 will be described in detail later.

The laminate 10A is actually processed and used as an element of a touch panel sensor. In Figure 1(A), number 10 represents the laminate after processing.

In the laminate 10 after processing, the excess portion of the film-like metal layer 14 in the laminate 10A before processing is removed, and only a large number of ultrafine wires S1 are left as the metal layer 14. , the remaining ultrafine lines S1 are parallel to each other to form electrodes 14D in a striped pattern.

The blackening film 16 also has its excess portion removed, leaving only the portion covering the upper surface of the drawing of the ultra-fine line S1 as the ultra-fine line S2, and these are incident on the upper surface of the drawing of the ultra-fine line S1. It has the function of absorbing light and suppressing reflection of light from the ultra-fine wire (S1).

These ultrafine lines S1 and S2 can be formed, for example, by a wet etching method using an etching solution such as ferric chloride.

Figure 1(B) shows another example of a laminated body. Like the laminates 20A and 20 shown in the same figure, it is also possible to form a blackening film 16 between the metal layer 14 and the transparent substrate 12 by laminating them.

In addition, like the laminates 22A and 22 shown in FIG. 2, a transparent base material 12, a first blackening film 16, a metal layer 14, and a second blackening film 16 are formed from the bottom upward in the figure. are sequentially laminated to form a second blackening film 16 that becomes a dark color layer on the upper surface of the figure opposite to the base material 12 of the metal layer 14, and the metal layer 14 Also on the lower side, that is, between the metal layer 14 and the base material 12, it is also possible to laminate the first blackening film 16, which becomes a similar dark color layer.

<2. Black screen>

Next, the blackening film 16 of this embodiment is explained.

The blackening film 16 is made of CuNiCo alloy oxide whose composition is expressed as (Cu _a Ni _b Co _c ) _100-x O _x . Here, a represents the proportion of Cu in the CuNiCo alloy (at%), b represents the proportion of Ni in the CuNiCo alloy (at%), and c represents the proportion of Co in the CuNiCo alloy (at%). , x represents the proportion (at%) of O in the CuNiCo alloy oxide. In this example, a, b, c, and x are defined as a+b+c=100, 0.30≤a/(a+b+c)≤0.70, 10≤b≤65, 0.1≤c, 30≤x≤50.

The reasons for limitation of each chemical component in the blackening film 16 are explained below.

Cu is an element effective in darkening the film by forming it into an oxide and lowering the reflectance of the film. If the proportion of Cu (a) in the CuNiCo alloy is excessively small, the proportion of Ni and Co (b+c) relatively increases, and thus the etching property using ferric chloride deteriorates. On the other hand, when the ratio (a) of Cu is excessively large, the ratio of Ni and Co (b+c) relatively decreases, and the environmental test characteristics deteriorate. For this reason, in this example, the Cu ratio (a) is specified as 0.30≤a/(a+b+c)≤0.70. Preferably, 0.40≤a/(a+b+c)≤0.70.

Ni is an element effective in increasing the corrosion resistance and discoloration resistance of the blackening film, and in this example to obtain this effect, the ratio (b) of Ni to the CuNiCo alloy is set to 10 (at%) or more. However, even when Ni is contained, localized discoloration may occur under high temperature and high humidity, and the discoloration may spread starting from this spotty discoloration area. Since this spot discoloration becomes more noticeable as the Ni ratio increases, in this example, the Ni ratio (b) is specified as 10≤b≤65. Preferably, it is 30≤b≤50, and more preferably, it is 40≤b≤50.

Co is an element effective in suppressing the occurrence of the above-mentioned spot discoloration. In order to obtain that effect, in this example, the proportion (c) of Co in the CuNiCo alloy is set to 0.1 (at%) or more. However, since excessive addition increases the reflectance, it is desirable to set the upper limit to 20 (at%). A more preferable range is 1≤c≤10.

In the blackening film made of the oxide of CuNiCo alloy, O can suppress the reflectance low and improve the environmental test characteristics by increasing its ratio (x). However, if the ratio (x) is excessively increased, the etching properties deteriorate, so in this example, the ratio (x) is specified as 30≤x≤50.

In addition, it has been confirmed that within the range specified in this way, there is a trade-off relationship between electrical resistivity and etching properties, and when it is desired to selectively increase etching properties, the ratio of O (x) must be set within the range of 30 ≤ x < 40. It is desirable to do it within. On the other hand, when it is desired to selectively obtain excellent electrical resistivity, it is desirable to set the ratio (x) within the range of 40≤x≤50.

To form a blackening film, a reactive sputtering method containing oxygen gas can be suitably used. Specifically, balanced magnetron sputtering method, unbalanced magnetron sputtering method, ion plating method, etc. can be mentioned. The composition of the metal component of the blackening film formed by sputtering is almost the same as that of the target for sputtering, and film formation by sputtering is also excellent in manufacturability.

<3. Target>

The target for sputtering of this embodiment is used for forming the blackening film, contains Cu, Ni, and Co, and has a composition expressed as Cu _a Ni _b Co _c . However, the target may contain unavoidable impurities.

Here, a represents the proportion of Cu in the CuNiCo alloy (at%), b represents the proportion of Ni in the CuNiCo alloy (at%), and c represents the proportion of Co in the CuNiCo alloy (at%). , these a, b, and c are defined as a+b+c=100, 0.30≤a/(a+b+c)≤0.70, and 10≤b≤65, respectively.

The reason that these a, b, and c are defined in the same range as the composition of the blackening film is based on the fact that the composition of the metal component of the blackening film formed by the sputtering method is almost the same as the composition of the target for sputtering.

This target can be manufactured by manufacturing a block with a predetermined composition using a solvent and cutting it out from there.

Additionally, depending on the case, it can be manufactured by mixing powders containing the constituent elements and pressurizing the mixed powder from cold to hot. The raw material powder may be a pure metal or alloy containing component elements. Molding methods include, for example, cold isostatic pressing (CIP), hot isostatic pressing (HIP), hot extrusion, and ultra-high pressure hot pressing.

(Example)

Next, embodiments of the present invention will be described in detail below. In this example, a laminate provided with a blackening film made of a metal oxide with the composition shown in Tables 1 and 2 below was produced, and the reflectance, environmental test characteristics, electrical resistivity, and etching properties were evaluated.

<Production of laminate>

A target was produced using a solvent so as to have the metal composition shown in Tables 1 and 2 above.

Next, using the manufactured target, a film thickness of 30 nm was applied to the surface of the glass substrate for evaluation (size: 100 mm in diameter x 0.5 mm in thickness) or the surface of the Cu metal film formed on the surface of the glass substrate by the reactive sputtering method. A blackening film of ∼50 nm was formed.

The film formation conditions for the blackening film by sputtering are as follows.

·Vacuum: 1×10 ^-4 Pa or less

·Film formation gas: Mixed gas of Ar gas and oxygen gas

·Sputter pressure: 0.15Pa

·Sputter power: 150W

<Evaluation of reflectance>

Reflectance was measured based on JIS K 7105:2008 using a laminate consisting of a blackening film/Cu metal film/substrate layer structure. In detail, the reflectance was measured for every 50 nm of wavelength for visible light (wavelength 400 nm to 800 nm) using an ultraviolet-visible spectrophotometer, and the average value was calculated as the reflectance. The reflectance was measured by measuring the reflected light when looking at the substrate side from the blackening film side, that is, measuring the reflected light when light was incident on the substrate side from the blackening film side, and evaluating it based on the following evaluation criteria. The results are shown in Tables 1 and 2.

○: Reflectance is less than 15%

△: Reflectance is 15% or more, less than 20%

×: Reflectance is 20% or more

<Evaluation of environmental test characteristics>

As shown in Figure 3, a laminate consisting of a layer structure of blackening film/Cu metal film/blackening film/substrate is used, and this laminate is stored and maintained in an atmospheric atmosphere of 85°C x 85%RH (relative humidity). , the brightness (L*) and chromaticity (a*, b*) of the film surface of the laminate are measured with a spectroscopic colorimeter every 100 hours, and the color difference (ΔE*) is based on the start of the test (0 hours) defined by the following calculation formula ) was calculated.

The time when the color difference ΔE* was 5 or less was considered the useful time, and was evaluated using the following evaluation criteria. The results are shown in Tables 1 and 2.

○: When the content time is more than 1000 hours

△: When the content time is more than 500 hours but less than 1000 hours

×: When the content time is less than 500 hours

<Evaluation of electrical resistivity>

A laminate consisting of a layered structure of blackening film (thickness 50 nm) / base material was manufactured, measurement was made at five locations on the blackening film by the four-probe method, and the electrical resistivity (Ω·cm) was calculated from the average value, and the following evaluation criteria were used. It was evaluated as In the measurement by the four-probe method, a low resistivity meter (MCP-T610 manufactured by Nitto Seiko Analytech Co., Ltd.) was used as a measuring instrument, and a PSP probe was used as a measuring probe. The results are shown in Tables 1 and 2.

○: Less than 1Ω·cm

△: 1Ω·cm or more, less than 10Ω·cm

×: 10Ω·cm or more

<Evaluation of etching properties>

A laminate consisting of a layered structure of blackening film (thickness 50 nm)/substrate was produced, a 20 mm square sample was cut from this laminate, and this sample was mixed with 1 mass% of ferric chloride and the remainder. It was immersed in an etching solution made of water. Then, the time until the blackening film formed on the substrate was completely dissolved was measured and evaluated based on the following evaluation criteria. The results are shown in Tables 1 and 2.

○: When the entire amount is dissolved in 5 to 10 seconds

×: Cases other than the above

The following points can be seen from the evaluation results in Tables 1 and 2.

Comparative examples 1 to 10 are examples in which the blackening film was composed of an oxide of a single metal. In Comparative Examples 1 to 10, blackening films were formed using any of Cu, Ni, Co, W, and Cr. Regarding reflectance, good results were obtained in Comparative Examples 5 to 8 using Co or W, but the evaluation results of environmental resistance test characteristics in Comparative Examples 5 to 8 were “×”. Additionally, in the example using a single metal other than Cu, the evaluation of etching properties was also “×”.

Comparative Examples 11 to 18 are examples in which the blackening film was composed of an oxide of an alloy consisting of Cu and one type of metal other than Cu. In the case of CuNi alloy (Comparative Examples 11 and 12) and CuCo alloy (Comparative Examples 13 and 14), the environmental test characteristics are improved, but the target service life of 1000 hours or more is not achieved because spot discoloration still occurs. .

Comparative Examples 19 to 28 are examples in which the blackening film is composed of oxide of CuNiCo alloy, but the ratio of certain elements is different from the claims of the present invention. In Comparative Examples 19 to 22 and Comparative Examples 24 to 27, where the O ratio (x) is 20 at%, which is lower than the lower limit of the present invention, the reflectance evaluation was “×”, and the target reflectance suppression effect was not obtained.

Comparative Examples 22 and 23 are examples in which the Ni ratio (b) was 70 at%, which exceeded the upper limit of the present invention. In these examples, because the proportion of Ni was high, spotty discoloration occurred, and the evaluation of the environmental resistance test characteristics was "×".

Comparative Examples 27 and 28 are examples in which the Ni ratio (b) was 5 at%, which was below the lower limit of the present invention. In these examples as well, discoloration of the film surface occurred, and the evaluation of the environmental resistance test characteristics was “×”.

As described above, in each comparative example, the evaluation of at least one of the reflectance and environmental test characteristics fell short of the target.

On the other hand, for Examples 1 to 27, which are made of CuNiCo alloy oxide and have blackening films whose ratio of constituent elements satisfies the provisions of the present invention, good results were obtained in both evaluations of reflectance and environmental resistance test characteristics. there is.

Looking at each Example in more detail, there is a trade-off relationship between electrical resistivity and etching property, and as shown in Examples 1 to 3, Examples 10 to 12, and Examples 19 to 21, the ratio of O (x) When set to 30 ≤ As shown in , if the O ratio (x) is set to 40≤x≤50, it can be seen that a blackening film with electrical resistivity suppressed to less than 1Ω·cm can be obtained.

Although the embodiments and examples of the present invention have been described in detail above, this is only an example. The present invention can be implemented with various modifications without departing from its spirit.

This application is based on Japanese Patent Application No. 2022-066558, filed on April 13, 2022, the contents of which are incorporated herein by reference.

Claims (4)

It has a composition expressed as Cu _a Ni _b Co _c , where a represents the proportion of Cu in at%, b represents the proportion of Ni in at%, and c represents the proportion of Co in at%, a+b+c=100 , 0.30≤a/(a+b+c)≤0.70, 10≤b≤65, 0.1≤c. A target for sputtering. The composition is made of a metal oxide expressed as (Cu _a Ni _b Co _c ) _{100-x O} The ratio of Co is expressed as at%, and x represents the ratio of O as at%, a+b+c=100, 0.30≤a/(a+b+c)≤0.70, 10≤b≤65, 0.1≤c, 30≤x≤50 A black film characterized by being . According to paragraph 2,
A blackening film, characterized in that x is 30≤x<40. According to paragraph 2,
Blackening film, characterized in that x is 40≤x≤50.