KR20180103927A - Blackening plating liquid and conductive substrate manufacturing method - Google Patents

Abstract

There is provided a blackening plating solution comprising nickel ions, copper ions, and a pH adjusting agent, wherein the pH adjusting agent is an alkali metal hydroxide.

Description

Blackening plating liquid and conductive substrate manufacturing method

The present invention relates to a blackening plating liquid and a conductive substrate manufacturing method.

The capacitive touch panel detects the change in capacitance caused by an object approaching the panel surface, thereby converting the position information of an object in proximity on the surface of the panel into an electrical signal. Since the conductive substrate used in the capacitive touch panel is provided on the surface of the display, it is required that the conductive layer material of the conductive substrate has low reflectance and is difficult to visually recognize.

Therefore, as a material of the conductive layer used in the capacitive touch panel, a material having a low reflectance and hardly visible is used, and wirings are formed on a transparent substrate or a transparent film.

For example, Patent Document 1 discloses a transparent conductive film comprising a polymer film and a transparent conductive film composed of a metal oxide formed thereon by a vapor phase film forming method. As the transparent conductive film made of a metal oxide, An indium-tin oxide (ITO) film is used.

In recent years, however, a large-sized display of a display including a touch panel is being developed, and a large area is also required for a conductive substrate such as a transparent conductive film for a touch panel. However, the ITO has a high electric resistance value and thus can not cope with the large-sized conductive substrate.

Thus, it has been studied to use a metal such as copper instead of ITO as the material of the conductive layer. However, since the metal has a metallic luster, there is a problem that the visibility of the display is deteriorated by reflection. Thus, a conductive substrate which has been subjected to a blackening treatment in which a layer made of a black material is formed on the surface of a conductive layer by a dry method has been studied.

However, it takes a long time to perform sufficient blackening treatment on the surface of the conductive layer by the dry method, resulting in low productivity.

Thus, the inventors of the present invention have studied the blackening treatment by the wet method in view of the fact that the vacuum environment required in the dry method is not required, the facilities can be simplified, and the productivity is excellent. Specifically, it has been studied to form a blackening layer by a wet process using a plating solution containing Ni and Zn as main components.

Japanese Unexamined Patent Publication No. 2003-151358

However, in the case of performing the blackening treatment for forming the blackening layer by the wet method, that is, the wet plating method using the plating solution containing Ni and Zn as the main components, the blackening layer to be formed is, The reactivity was high in some cases. When a conductive substrate having a desired wiring pattern is fabricated, a copper layer and a blackening layer, which are conductive layers, are formed and patterned by etching. However, from the difference in reactivity between the copper layer and the blackening layer relative to the etching solution, It has been difficult to form the pattern into a shape.

In view of the problems of the prior art, it is an object of the present invention to provide a blackening plating solution capable of forming a blackening layer which can be patterned in a desired shape when etching together with a copper layer.

According to an aspect of the present invention, there is provided a blackening plating solution comprising nickel ions, copper ions, and a pH adjusting agent, wherein the pH adjusting agent is an alkali metal hydroxide.

According to one aspect of the present invention, there is provided a blackening plating solution capable of forming a blackening layer that can be patterned into a desired shape when etching together with a copper layer.

1A is a cross-sectional view of a conductive substrate according to an embodiment of the present invention.
1B is a cross-sectional view of a conductive substrate according to an embodiment of the present invention.
2A is a cross-sectional view of a conductive substrate according to an embodiment of the present invention.
2B is a cross-sectional view of a conductive substrate according to an embodiment of the present invention.
3 is a top view of a conductive substrate having mesh-shaped wiring according to an embodiment of the present invention.
4A is a cross-sectional view taken along the line AA 'in FIG.
4B is a cross-sectional view taken along the line AA 'in Fig.

Hereinafter, one embodiment of the blackening plating liquid and conductive substrate of the present invention will be described.

(Blackening plating solution)

The blackening plating solution of the present embodiment contains nickel ions, copper ions, and a pH adjusting agent, and an alkali metal hydroxide may be used as a pH adjusting agent.

As described above, for example, the blackening layer formed by a wet process using a plating solution containing Ni and Zn as main components has a higher reactivity to the etching solution than that of the copper layer, and is patterned into a desired shape when etching together with the copper layer It was difficult to do. Thus, the inventors of the present invention have carefully examined a blackening plating solution capable of forming a blackening layer that can be patterned into a desired shape when etching together with a copper layer.

Thus, the inventors of the present invention have found that when the blackening layer is made of a layer containing nickel and copper, the reactivity of the blackening layer with respect to the etching solution can be suppressed, and even when etching is performed simultaneously with the copper layer It is possible to obtain a desired shape. Further, it has also been found that the blackening layer contains nickel and copper, so that the color can be suppressed from reflecting on the surface of the copper layer. On the other hand, the desired shape in the case of etching the copper layer and the blackening layer at the same time means, for example, a shape and a pattern including wiring with a wiring width of 10 mu m or less.

Therefore, the blackening plating solution of the present embodiment is preferably a plating solution capable of forming a layer containing nickel and copper as a metal component, and the blackening plating solution of this embodiment may contain nickel ions and copper ions.

The concentration of each component in the blackening plating liquid is not particularly limited, but the nickel ion concentration in the blackening plating liquid is preferably 2.0 g / l or more, more preferably 3.0 g / l or more. This is because, by setting the nickel ion concentration in the blackening plating liquid to 2.0 g / l or more, the blackening layer can be made to be a color very suitable for suppressing light reflection on the surface of the copper layer, and the reflectance of the conductive substrate can be suppressed .

The upper limit of the nickel ion concentration in the blackening plating solution is not particularly limited, but is preferably 20.0 g / l or less, more preferably 15.0 g / l or less. This is because, by setting the nickel ion concentration in the blackening plating liquid to 20.0 g / l or less, it is possible to prevent the nickel component in the blackening layer formed from being excessive and prevent the surface of the blackening layer from becoming like a plated nickel surface, Can be suppressed.

The copper ion concentration in the blackening plating liquid is preferably 0.005 g / l or more, more preferably 0.008 g / l or more. This is because, when the copper ion concentration in the blackening plating solution is 0.005 g / l or more, the blackening layer is made to be a color very suitable for suppressing light reflection on the surface of the copper layer and the reactivity of the blackening layer to the etching solution is made very suitable This is because, even when the blackening layer is etched together with the copper layer, the pattern can be more reliably patterned into a desired shape.

The upper limit value of the copper ion concentration in the blackening plating solution is not particularly limited, but is preferably 1.02 g / l or less, more preferably 0.5 g / l or less, for example. This is because, by setting the copper ion concentration in the blackening plating liquid to 1.02 g / l or less, it is possible to suppress the reactivity of the blackened layer formed to an excessively high level with respect to the etchant, and the blackening layer is very suitable for suppressing light reflection on the surface of the copper layer This is because the reflectance of the conductive substrate can be suppressed by using the color.

The method of supplying nickel ions and copper ions when preparing the blackening plating solution is not particularly limited and can be supplied in a salt state, for example. For example, sulfamates and sulfates may be suitably used as needed. On the other hand, the kind of the salt may be the same kind of salt for each metal element, or a salt of another kind may be used at the same time. Specifically, for example, a blackening plating solution may be prepared using the same kind of salt as nickel sulfate or copper sulfate. In addition, for example, other types of salts such as nickel sulfate and copper sulfamate may be used at the same time to prepare a blackening plating solution.

The blackening plating solution of this embodiment may contain a pH adjusting agent.

As the pH adjusting agent, an alkali metal hydroxide may preferably be used. This is because the use of an alkali metal hydroxide as a pH adjusting agent can greatly reduce the reflectance of a conductive substrate having a blackening layer formed by using the blackening plating solution. the reason why the reflectance of a conductive substrate having a blackening layer formed using the blackening plating solution can be suppressed to a low level when an alkali metal hydroxide is used as the pH adjusting agent is not clearly known but it is not clear whether the hydroxide ion supplied to the blackening plating solution is nickel oxide To promote the precipitation of water. Precipitation of nickel oxide is promoted, so that the blackening layer can be made into a color very suitable for suppressing light reflection on the surface of the copper layer. Thus, it is considered that the reflectance of the conductive substrate having the blackening layer can be suppressed.

As the alkali metal hydroxide which is a pH adjusting agent, for example, at least one selected from sodium hydroxide, potassium hydroxide and lithium hydroxide can be used. Particularly, the alkali metal hydroxide which is a pH adjusting agent is more preferably one or more selected from sodium hydroxide and potassium hydroxide. This is because sodium hydroxide and potassium hydroxide are particularly easy to obtain and cost-effective.

The pH of the blackening plating solution of the present embodiment is not particularly limited, but is preferably 4.0 to 5.2, more preferably 4.5 to 5.0, for example.

This is because, by setting the pH of the blackening plating liquid to 4.0 or more, occurrence of color unevenness in the blackening layer can be suppressed more reliably when the blackening layer is formed by using the blackening plating liquid, and light reflection on the surface of the copper layer can be suppressed This is because it is possible to form a blackening layer having a color which is very suitable for the blackening. This is because the pH of the blackening plating solution is adjusted to 5.2 or less, whereby the precipitation of a part of the components of the blackening plating solution can be suppressed.

On the other hand, the blackening plating solution of the present embodiment preferably contains a pH adjusting agent so that the pH is in the above range.

The blackening plating solution of the present embodiment may further include amide sulfuric acid which functions as a complexing agent in addition to nickel ions and copper ions. By containing amide sulfuric acid, a blackening layer of a color that is very suitable for suppressing light reflection on the surface of the copper layer can be obtained.

The content of the amide sulfuric acid in the blackening plating solution is not particularly limited and can be arbitrarily selected depending on the degree of suppression of the reflectance required for the blackening layer to be formed.

For example, the concentration of amide sulfuric acid in the blackening plating liquid is not particularly limited, but is preferably 1 g / l or more and 50 g / l or less, more preferably 5 g / l or more and 20 g / l or less. This is because by setting the concentration of amide sulfuric acid to 1 g / l or more, the blackening layer can be made to be a color which is very suitable for suppressing light reflection on the surface of the copper layer, and the reflectance of the conductive substrate can be suppressed. In addition, even when excess amount of amide sulfuric acid is added in an amount exceeding 50 g / l, the effect of suppressing the reflectance of the conductive substrate is not significantly changed, and is preferably 50 g / l or less as described above.

The blackening plating solution of the present embodiment may contain an arbitrary component in addition to the components described so far. Examples of the optionally contained component include a pit inhibitor for nickel plating. Examples of the anti-pinning agent for nickel plating include Fetris S (trade name) manufactured by Nippon Chemical Industrial Co., and nickel gel (trade name) NAW4 (trade name) manufactured by Rohm and Haas.

According to the blackening plating solution of the present embodiment described above, it is possible to form a blackening layer that can be patterned into a desired shape when etching together with the copper layer.

The blackening plating solution of the present embodiment can be suitably used when necessary in forming a blackening layer which can sufficiently suppress light reflection on the surface of the copper layer of the conductive substrate. Further, since the blackening layer can be formed by a wet process such as an electrolytic plating method using the blackening plating solution of the present embodiment, a blackening layer can be formed with good productivity as compared with a blackening layer which has been formed by a dry method in the past.

(Conductive substrate)

Next, a structural example of a conductive substrate including a blackening layer formed by using the blackening plating solution of the present embodiment will be described.

The conductive substrate of the present embodiment may include a transparent substrate (base material), a copper layer disposed on at least one side of the transparent substrate, and a blackening layer formed using a blackening plating solution on the copper layer.

On the other hand, the conductive substrate in the present embodiment includes a substrate having a copper layer and a blackening layer on the surface of a transparent substrate before patterning the copper layer or the like, and a substrate in which a copper layer or the like is patterned, that is, a wiring substrate .

First, each member included in the conductive substrate will be described below.

The transparent substrate is not particularly limited, and preferably a transparent substrate such as a resin substrate (resin film) or a glass substrate that transmits visible light can be used.

As a material of the resin substrate through which visible light is transmitted, it is preferable to use a resin such as a polyamide resin, a polyethylene terephthalate resin, a polyethylene naphthalate resin, a cycloolefin resin, a polyimide resin, a polycarbonate resin Can be used. Particularly preferably, PET (polyethylene terephthalate), COP (cycloolefin polymer), PEN (polyethylene naphthalate), polyamide, polyimide, polycarbonate and the like can be used as the material of the resin substrate for transmitting visible light have.

The thickness of the transparent substrate is not particularly limited and may be arbitrarily selected depending on the strength, electrostatic capacity, light transmittance, and the like required when the substrate is a conductive substrate. The thickness of the transparent substrate may be, for example, 10 占 퐉 or more and 200 占 퐉 or less. In particular, when used as a touch panel, the thickness of the transparent base material is preferably 20 탆 or more and 120 탆 or less, more preferably 20 탆 or more and 100 탆 or less. For example, in applications where it is required to reduce the thickness of the entire display, it is preferable that the thickness of the transparent substrate is not less than 20 μm and not more than 50 μm.

The total light transmittance of the transparent substrate is preferably high. For example, the total light transmittance is preferably 30% or more, more preferably 60% or more. When the total light transmittance of the transparent base material is in the above range, the visibility of the display can be sufficiently secured when used for a touch panel, for example.

On the other hand, the total light transmittance of the transparent substrate can be evaluated by the method specified in JIS K 7361-1.

Next, the copper layer will be described.

The method of forming the copper layer on the transparent substrate is not particularly limited, but it is preferable not to place the adhesive between the transparent substrate and the copper layer in order to reduce the light transmittance. That is, the copper layer is preferably formed directly on at least one side of the transparent substrate. On the other hand, as will be described later, when the adhesion layer is disposed between the transparent substrate and the copper layer, the copper layer is preferably formed directly on the upper surface of the adhesion layer.

In order to directly form a copper layer on the upper surface of a transparent substrate or the like, it is preferable that the copper layer has a copper thin film layer. Further, the copper layer may have a copper thin film layer and a copper plating layer.

For example, a copper thin film layer may be formed on a transparent substrate by a dry plating method to form the copper thin film layer as a copper layer. Thereby, the copper layer can be formed directly on the transparent substrate without passing through the adhesive. On the other hand, as the dry plating method, for example, a sputtering method, a vapor deposition method, an ion plating method and the like can be preferably used.

When the thickness of the copper layer is increased, a copper layer having a copper thin film layer and a copper plating layer may be formed by forming a copper plating layer by an electroplating method which is a kind of wet plating method using a copper thin film layer as a power supply layer. The copper layer has the copper thin film layer and the copper plating layer, and in this case also, the copper layer can be formed directly on the transparent substrate without passing through the adhesive.

The thickness of the copper layer is not particularly limited, and when the copper layer is used as the wiring, it may be arbitrarily selected depending on the size of the current to be supplied to the wiring, the width of the wiring, and the like.

However, if the copper layer is thick, it takes a long time to etch to form a wiring pattern, so that side etching tends to occur and a problem that a thin line is difficult to be formed may occur. Therefore, the thickness of the copper layer is preferably 5 mu m or less, more preferably 3 mu m or less.

In addition, from the viewpoint that a sufficient electric current can be supplied by lowering the resistance value of the conductive substrate in particular, for example, the copper layer preferably has a thickness of 50 nm or more, more preferably 60 nm or more, desirable.

On the other hand, when the copper layer has the copper thin film layer and the copper plating layer as described above, it is preferable that the total thickness of the copper thin film layer and the copper plating layer is in the above range.

In any case where the copper layer is composed of a copper thin film layer or in the case of having a copper thin film layer and a copper plating layer, the thickness of the copper thin film layer is not particularly limited, but is preferably 50 nm or more and 500 nm or less, for example.

The copper layer can be used as wiring, for example, by patterning the copper layer in a desired wiring pattern, as described later. Since the copper layer can lower the electric resistance value of the ITO used as the conventional transparent conductive film, the electric resistance value of the conductive substrate can be reduced by providing the copper layer.

Next, the blackening layer will be described.

The blackening layer can be formed by using the above-described blackening plating solution. For this purpose, for example, a copper layer may be formed and then formed on the upper surface of the copper layer by a wet process such as electrolytic plating.

Since the blackening plating solution has been described above, its explanation is omitted here.

The thickness of the blackening layer is not particularly limited, but is preferably 30 nm or more, for example, and more preferably 50 nm or more. This is because when the thickness of the blackening layer is 30 nm or more, light reflection on the surface of the copper layer can be suppressed to a large extent.

The upper limit of the thickness of the blackening layer is not particularly limited, but if it is thicker than necessary, the time required for film formation, the time required for etching when forming wiring, and the like increase, resulting in an increase in cost. Therefore, the thickness of the blackening layer is preferably 120 nm or less, more preferably 90 nm or less.

On the other hand, when the blackening layer is formed by the above-described blackening plating solution, the blackening layer may be a layer containing nickel and copper. In addition, components derived from various additive components included in the above-described blackening plating solution may also be contained.

The conductive substrate may have an arbitrary layer other than the above-described transparent substrate, copper layer, and blackening layer. For example, an adhesive layer may be provided.

An example of the structure of the adhesion layer will be described.

As described above, although the copper layer can be formed on the transparent substrate, when the copper layer is directly formed on the transparent substrate, the adhesion between the transparent substrate and the copper layer may not be sufficient. Therefore, when the copper layer is formed directly on the upper surface of the transparent substrate, the copper layer may peel off from the transparent substrate during the manufacturing process or use.

Thus, in the conductive substrate of the present embodiment, in order to improve the adhesion between the transparent substrate and the copper layer, the adhesion layer may be disposed on the transparent substrate. That is, it may be a conductive substrate having an adhesive layer between the transparent substrate and the copper layer.

By disposing the adhesive layer between the transparent substrate and the copper layer, the adhesion between the transparent substrate and the copper layer can be improved, and the copper layer can be prevented from peeling off from the transparent substrate.

Further, the adhesion layer can also function as a blackening layer. Thus, it is possible to suppress the light reflection of the copper layer with respect to the light coming from the lower side of the copper layer, that is, the transparent substrate side.

The material constituting the adhesion layer is not particularly limited and the adhesion between the transparent substrate and the copper layer, the degree of light reflection suppression required on the surface of the copper layer, and the environment (for example, humidity, temperature) And the like.

The adhesion layer preferably contains at least one kind of metal selected from Ni, Zn, Mo, Ta, Ti, V, Cr, Fe, Co, W, Cu, Sn and Mn. Further, the adhesion layer may further include at least one element selected from carbon, oxygen, hydrogen, and nitrogen.

The adhesion layer may include a metal alloy containing at least two kinds of metals selected from Ni, Zn, Mo, Ta, Ti, V, Cr, Fe, Co, W, Cu, Sn and Mn. Also in this case, the adhesion layer may further include at least one element selected from carbon, oxygen, hydrogen, and nitrogen. The metal alloy containing at least two kinds of metals selected from Ni, Zn, Mo, Ta, Ti, V, Cr, Fe, Co, W, Cu, Sn and Mn is preferably Cu- Ti-Fe alloy, Cu-Ni-Fe alloy, Ni-Cu alloy, Ni-Zn alloy, Ni-Ti alloy, Ni-W alloy, Ni-Cr alloy and Ni-Cu-Cr alloy.

The method of forming the adhesion layer is not particularly limited, but it is preferable to form the adhesion layer by a dry plating method. As the dry plating method, for example, a sputtering method, an ion plating method, a vapor deposition method, or the like can be preferably used. In the case of forming the adhesion layer by the dry method, it is more preferable to use the sputtering method in view of easy control of the film thickness. On the other hand, at least one kind of element selected from carbon, oxygen, hydrogen, and nitrogen may be added to the adhesion layer as described above. In this case, reactive sputtering may be further preferably used.

When the adhesive layer contains one or more elements selected from carbon, oxygen, hydrogen, and nitrogen, a gas containing one or more elements selected from carbon, oxygen, hydrogen, and nitrogen in the atmosphere for forming the adhesion layer By weight, to the adhesion layer. For example, when carbon is added to the adhesion layer, carbon monoxide gas and / or carbon dioxide gas is added. When oxygen is added, oxygen gas is added. When hydrogen is added, hydrogen gas and / Nitrogen gas may be added to the atmosphere for dry plating.

It is preferable that a gas containing at least one element selected from carbon, oxygen, hydrogen and nitrogen is added to an inert gas to be an atmospheric gas for dry plating. The inert gas is not particularly limited, but argon can be preferably used, for example.

As described above, by forming the adhesion layer by a dry plating method, adhesion between the transparent substrate and the adhesion layer can be improved. Since the adhesive layer can contain, for example, a metal as a main component, adhesion with the copper layer is also good. Therefore, by disposing the adhesion layer between the transparent substrate and the copper layer, peeling of the copper layer can be suppressed.

The thickness of the adhesive layer is not particularly limited, but is preferably 3 nm or more and 50 nm or less, more preferably 3 nm or more and 35 nm or less, and more preferably 3 nm or more and 33 nm or less.

When the adhesive layer functions also as a blackening layer, that is, when reflection of light in the copper layer is suppressed, the thickness of the adhesive layer is preferably 3 nm or more as described above.

The upper limit value of the thickness of the adhesion layer is not particularly limited, but if it is made thicker than necessary, the time required for film formation, the time required for etching at the time of formation of wiring, and the like increase, resulting in an increase in cost. Therefore, the thickness of the adhesion layer is preferably 50 nm or less as described above, more preferably 35 nm or less, and more preferably 33 nm or less.

Next, a configuration example of the conductive substrate will be described.

As described above, the conductive substrate of the present embodiment may have a transparent substrate, a copper layer, and a blackening layer. In addition, a layer such as an adhesive layer may be optionally provided.

A specific configuration example will be described below with reference to Figs. 1A, 1B, 2A, and 2B. Figs. 1A, 1B, 2A, and 2B show examples of cross-sectional views on a plane parallel to the stacking direction of the transparent substrate, the copper layer, and the blackening layer of the conductive substrate of the present embodiment.

The conductive substrate of the present embodiment may have, for example, a structure in which a copper layer and a blackening layer are stacked in this order from a transparent substrate side on at least one side of a transparent substrate.

Specifically, for example, as in the case of the conductive substrate 10A shown in Fig. 1A, the copper layer 12 and the blackening layer 13 are stacked one by one in this order on one surface 11a side of the transparent substrate 11, can do. As in the case of the conductive substrate 10B shown in Fig. 1B, copper layers 12A and 12B and a blackening layer (not shown) are formed on one surface 11a and the other surface 11b side of the transparent substrate 11, 13A, and 13B may be stacked one by one in this order.

Further, as an arbitrary layer, for example, an adhesion layer may be further provided. In this case, for example, a structure in which the adhesion layer, the copper layer, and the blackening layer are formed in order from the transparent substrate side on at least one side of the transparent substrate can be adopted.

Specifically, for example, the adhesion layer 14, the copper layer 12, the blackening layer 13, and the adhesion layer 14 are formed on one surface 11a side of the transparent substrate 11, as in the conductive substrate 20A shown in Fig. As shown in FIG.

In this case as well, an adhesive layer, a copper layer, and a blackening layer may be laminated on both sides of the transparent substrate 11. Concretely, as in the case of the conductive substrate 20B shown in Fig. 2B, the adhesion layers 14A and 14B and the copper layers 12A and 12B are formed on one surface 11a and the other surface 11b side of the transparent substrate 11, 12B, and the blackening layers 13A, 13B in this order.

On the other hand, when a copper layer, a blackening layer, or the like is laminated on both surfaces of the transparent substrate as shown in Figs. 1B and 2B, the layers laminated on and under the transparent substrate 11 are arranged symmetrically with the transparent substrate 11 as a symmetry plane An example is shown, but the present invention is not limited to this. For example, the structure on one surface 11a side of the transparent substrate 11 in Fig. 2B may be a structure of the copper layer 12A and the blackening layer 13A without the adhesive layer 14A as in the configuration of Fig. The layers laminated on and under the transparent substrate 11 may have an asymmetric structure.

Incidentally, in the conductive substrate of the present embodiment, by providing the copper layer and the blackening layer on the transparent substrate, it is possible to suppress the reflection of light by the copper layer and suppress the reflectance of the conductive substrate.

The degree of reflectivity of the conductive substrate of the present embodiment is not particularly limited, but it is preferable that the reflectance is low in order to improve display visibility when used as a conductive substrate for a touch panel, for example. For example, the average reflectance of light having a wavelength of 400 nm or more and 700 nm or less is preferably 55% or less, more preferably 18% or less, and more preferably 10% or less.

The reflectance can be measured by irradiating the blackened layer of the conductive substrate with light. Specifically, for example, when the copper layer 12 and the blackening layer 13 are stacked in this order on one surface 11a side of the transparent substrate 11 as shown in Fig. 1A, the blackening layer 13 The surface A of the blackening layer 13 can be irradiated with light so as to be irradiated with light. In the measurement, the average value of the values measured by irradiating the blackened layer 13 of the conductive substrate with light having a wavelength of 400 nm or more and 700 nm or less, for example, at a wavelength interval of 1 nm as described above, As shown in FIG.

The conductive substrate of the present embodiment is preferably used as a conductive substrate for a touch panel. In this case, the conductive substrate may be provided with a mesh-shaped wiring.

The conductive substrate having the mesh-shaped wiring can be obtained by etching the copper layer and the blackening layer of the conductive substrate of the present embodiment described so far.

For example, mesh-shaped wiring can be formed by wiring of two layers. A specific configuration example is shown in Fig. Fig. 3 shows a view of the conductive substrate 30 provided with the mesh-shaped wirings from the top surface side in the stacking direction of the copper layer or the like. The wirings 31A and 31B ) Is omitted for the layers other than the layer. In addition, the wiring 31B seen through the transparent substrate 11 is also shown.

The conductive substrate 30 shown in Fig. 3 has a transparent substrate 11, a plurality of wirings 31A parallel to the Y-axis direction, and wirings 31B parallel to the X-axis direction in the figure. On the other hand, the wirings 31A and 31B are formed by etching a copper layer, and a blackening layer (not shown) is formed on the upper or lower surface of the wirings 31A and 31B. In addition, the blackening layer is etched in the same shape as the wirings 31A and 31B.

The arrangement of the transparent substrate 11 and the wirings 31A and 31B is not particularly limited. Examples of the arrangement of the transparent substrate 11 and the wiring arrangement are shown in Figs. 4A and 4B. Figs. 4A and 4B correspond to cross-sectional views taken along the line A-A 'in Fig.

First, as shown in Fig. 4A, wirings 31A and 31B may be disposed on the upper and lower surfaces of the transparent substrate 11, respectively. On the other hand, in FIG. 4A, blackening layers 32A and 32B etched in the same shape as wiring are arranged on the upper surface of the wiring 31A and the lower surface of the wiring 31B.

4B, the pair of transparent substrates 11 are used, the wirings 31A and 31B are arranged on the upper and lower sides with one transparent substrate 11 therebetween, May be disposed between the transparent substrate 11. In this case also, blackening layers 32A and 32B etched in the same shape as wiring are arranged on the upper surfaces of the wirings 31A and 31B. On the other hand, as described above, the adhesion layer may be formed in addition to the copper layer and the blackening layer. Thus, in either case of Figs. 4A and 4B, for example, an adhesion layer may be formed between the wiring 31A and / or the wiring 31B and the transparent substrate 11. In the case of forming the adhesion layer, it is preferable that the adhesion layer is also etched in the same shape as the wirings 31A and 31B.

The conductive substrate having the mesh wiring shown in Figs. 3 and 4A is formed by laminating copper layers 12A and 12B and blackening layers 13A and 13B on both sides of the transparent member 11, for example, as shown in Fig. And can be formed of a conductive substrate provided.

The copper layer 12A and the blackening layer 13A on the side of one surface 11a of the transparent substrate 11 are first formed on the Y axis of FIG. Direction so as to be arranged at predetermined intervals along the X-axis direction. On the other hand, the X-axis direction in Fig. 1B means a direction parallel to the width direction of each layer. In addition, the Y-axis direction in Fig. 1B means a direction perpendicular to the paper in Fig. 1B.

The copper layer 12B and the blackening layer 13B on the other side 11b side of the transparent substrate 11 are patterned so that a plurality of line patterns parallel to the X axis direction of FIG. Etching is performed so as to be arranged.

By the above operation, the conductive substrate having the mesh wiring shown in Figs. 3 and 4A can be formed. On the other hand, both sides of the transparent substrate 11 can be etched simultaneously. That is, etching of the copper layers 12A and 12B and the blackening layers 13A and 13B can be performed at the same time. The conductive substrate further includes a patterned adhesion layer between the wirings 31A and 31B and the transparent substrate 11 in the same shape as the wirings 31A and 31B in Fig. 4A. The conductive substrate shown in Fig. And then etching it in the same manner.

The conductive substrate having the mesh wiring shown in Fig. 3 may be formed by using two conductive substrates shown in Figs. 1A and 2A. 1A, the copper layer 12 and the blackening layer 13 are formed on two conductive substrates shown in Fig. 1A, respectively, and a plurality of Are arranged so as to be arranged along the Y-axis direction at predetermined intervals. Then, two conductive substrates are adhered to each other so that the line-shaped patterns formed on the respective conductive substrates cross each other by the etching process, thereby making the conductive substrate having the mesh-shaped wiring. The surface to which the two conductive substrates are pasted when pasted together is not particularly limited. For example, the surface A in Fig. 1A in which the copper layer 12 and the like are laminated and the other surface 11b in Fig. 1A where the copper layer 12 and the like are not laminated are bonded to each other, The structure shown in Fig.

In addition, for example, the other surfaces 11b in FIG. 1A in which the copper layer 12 and the like are not laminated in the transparent substrate 11 may be bonded to each other to have a cross-sectional structure as shown in FIG. 4A .

On the other hand, a conductive substrate further including a patterned adhesion layer between the wirings 31A and 31B and the transparent substrate 11 in the same shape as the wirings 31A and 31B in Figs. 4A and 4B is shown in Fig. 1A The conductive substrate shown in Fig. 2A can be used instead of the conductive substrate.

The wiring width and the inter-wiring distance in the conductive substrate having the mesh-shaped interconnection shown in Figs. 3, 4A, and 4B are not particularly limited, and can be selected depending on, for example, the amount of electric current to flow through the interconnection.

However, according to the conductive substrate of the present embodiment, even when the blackening layer formed using the above-described blackening plating solution and the blackening layer and the copper layer are simultaneously etched to pattern the blackening layer and the copper layer, have. Concretely, for example, a wiring having a wiring width of 10 mu m or less can be formed. Therefore, it is preferable that the conductive substrate of the present embodiment includes a wiring having a wiring width of 10 mu m or less. The lower limit value of the wiring width is not particularly limited, but may be 3 mu m or more, for example.

3, 4A, and 4B show an example in which mesh-shaped wirings (wiring patterns) are formed by combining linear wirings, but the present invention is not limited to this, and the wirings constituting the wiring patterns may be arbitrary As shown in Fig. For example, in order to prevent moire (interference fringes) from occurring with the display image, the shapes of the wirings constituting the mesh-shaped wiring pattern may be various shapes such as jagged lines (zigzag lines) have.

The conductive substrate having the mesh-like wiring composed of the two-layer wiring in this manner can be preferably used, for example, as a conductive substrate for a projection-type electrostatic capacitance type touch panel.

According to the above-described conductive substrate of the present embodiment, it has a structure in which a blackening layer is laminated on a copper layer formed on at least one surface of a transparent substrate. Since the blackening layer is formed by using the blackening plating solution described above, the blackening layer can be easily patterned into a desired shape when the copper layer and the blackening layer are patterned by etching.

In addition, the blackening layer included in the conductive substrate of the present embodiment can be a conductive substrate in which the reflection of light is suppressed sufficiently on the surface of the copper layer to suppress the reflectance. In addition, for example, when used for a touch panel or the like, display visibility can be improved.

Further, since the blackening layer can be formed by the wet process using the above-described blackening plating solution, the conductive substrate can be produced with good productivity as compared with the case of forming the blackening layer using the conventional dry method.

(Conductive substrate manufacturing method)

Next, a structural example of the conductive substrate manufacturing method of the present embodiment will be described.

The conductive substrate manufacturing method of the present embodiment includes a copper layer forming step of forming a copper layer on at least one side of a transparent substrate and a blackening layer forming step of forming a blackening layer using a blackening plating solution on the copper layer .

On the other hand, as the blackening plating solution, the above-described blackening plating solution, specifically, a blackening plating solution containing nickel ions, copper ions, and a pH adjusting agent and whose pH adjuster is an alkali metal hydroxide can be used.

Hereinafter, the conductive substrate manufacturing method of the present embodiment will be described in detail.

On the other hand, by the conductive substrate manufacturing method of the present embodiment, the above-described conductive substrate can be suitably manufactured as required. Therefore, except for the points described below, the same structure as that of the above-described conductive substrate can be used, so that some explanation is omitted.

The transparent substrate to be provided in the copper layer forming step can be prepared in advance. The type of the transparent substrate to be used is not particularly limited, but it is preferable to use a transparent substrate such as a resin substrate (resin film) or a glass substrate that transmits visible light, as described above. The transparent substrate may be cut in advance to an arbitrary size if necessary.

It is preferable that the copper layer has a copper thin film layer as described above. Further, the copper layer may have a copper thin film layer and a copper plating layer. Thus, the copper layer forming step may have a step of forming a copper thin film layer by, for example, a dry plating method. The copper layer forming step may include a step of forming a copper thin film layer by a dry plating method and a step of forming a copper plating layer by an electroplating method which is one type of wet plating method using the copper thin film layer as a power supply layer.

The dry plating method used in the step of forming the copper thin film layer is not particularly limited, and for example, a vapor deposition method, a sputtering method, an ion plating method, or the like can be used. On the other hand, as the vapor deposition method, a vacuum vapor deposition method can be preferably used. The dry plating method used in the step of forming the copper thin film layer is more preferably a sputtering method because it is easy to control the film thickness.

Next, the step of forming the copper plating layer will be described. The conditions in the step of forming the copper plating layer by the wet plating method, that is, the electroplating treatment conditions, are not particularly limited, and the conditions according to the ordinary method may be employed. For example, a copper plating layer can be formed by supplying a substrate provided with a copper thin film layer to a plating bath containing a copper plating solution, controlling the current density, the transporting speed of the substrate, and the like.

Next, the blackening layer forming step will be described.

In the blackening layer forming step, the blackening layer can be formed by using the above-described blackening plating solution containing nickel ions, copper ions, and a pH adjusting agent and the pH adjuster being an alkali metal hydroxide.

The blackening layer can be formed by a wet process. Specifically, for example, a black layer can be formed on the copper layer by electrolytic plating in a plating bath containing the above-described blackening plating solution using a copper layer as a power supply layer. By forming the blackening layer by the electrolytic plating method using the copper layer as the power supply layer as described above, a blackening layer can be formed on the entire surface of the copper layer opposite to the surface facing the transparent substrate.

Since the blackening plating solution has been described above, the explanation is omitted.

In the conductive substrate manufacturing method of the present embodiment, an arbitrary step may be further performed in addition to the above-described steps.

For example, in the case of forming the adhesion layer between the transparent substrate and the copper layer, the adhesion layer forming step of forming the adhesion layer on the surface of the transparent substrate on which the copper layer is to be formed can be performed. In the case where the adhesion layer forming step is performed, the copper layer forming step can be performed after the adhesion layer forming step, and in the copper layer forming step, the copper thin film layer is formed on the substrate having the adhesion layer formed on the transparent substrate in this step .

In the adhesion layer forming step, the method of forming the adhesion layer is not particularly limited, but it is preferable to form the film by a dry plating method. As the dry plating method, for example, a sputtering method, an ion plating method, a vapor deposition method, or the like can be preferably used. When the adhesion layer is formed by the dry method, the sputtering method is more preferable because it is easy to control the film thickness. On the other hand, as described above, one or more kinds of elements selected from carbon, oxygen, hydrogen, and nitrogen may be added to the adhesion layer. In this case, reactive sputtering may be further preferably used.

The conductive substrate obtained in the conductive substrate manufacturing method of the present embodiment can be used for various purposes such as, for example, a touch panel. In the case of using for various purposes, it is preferable that the copper layer and the blackening layer included in the conductive substrate of the present embodiment are patterned. On the other hand, when the adhesion layer is formed, it is preferable that the adhesion layer is also patterned. The copper layer, the blackening layer and, in some cases, the adhesion layer can be patterned in accordance with a desired wiring pattern, and the copper layer, the blackening layer, and in some cases even the adhesion layer are patterned in the same shape .

Thus, the conductive substrate manufacturing method of the present embodiment can include a patterning step of patterning the copper layer and the blackening layer. In the case of forming the adhesion layer, the patterning step may be a step of patterning the adhesion layer, the copper layer and the blackening layer.

A specific method of the patterning process is not particularly limited and may be carried out by any method. For example, in the case of the conductive substrate 10A in which the copper layer 12 and the blackening layer 13 are laminated on the transparent substrate 11 as shown in Fig. 1A, the surface A of the blackening layer 13 A resist disposing step of disposing a resist having a desired pattern can be performed. Then, an etching step for supplying an etching liquid onto the surface (A) on the blackened layer 13, that is, the surface on which the resist is disposed, can be performed.

The etching solution used in the etching step is not particularly limited. However, the blackening layer formed in the conductive substrate manufacturing method of the present embodiment exhibits almost the same etching liquid reactivity as the copper layer. Therefore, the etching solution used in the etching step is not particularly limited, and an etching solution generally used for copper layer etching can be preferably used.

As the etching solution, it is preferable to use, for example, a mixed aqueous solution containing at least one selected from sulfuric acid, hydrogen peroxide (hydrogen peroxide solution), hydrochloric acid, copper chloride and ferric chloride. The content of each component in the etching solution is not particularly limited.

The etching solution may be used at room temperature. However, the etching solution may be used at an elevated temperature in order to increase the reactivity. For example, the etching solution may be heated to not less than 40 ° C and not more than 50 ° C.

The conductive substrate 10B in which the copper layers 12A and 12B and the blackening layers 13A and 13B are laminated on one surface 11a and the other surface 11b of the transparent substrate 11 as shown in Fig. A patterning process for patterning can be performed. In this case, for example, a resist disposing step of disposing a resist having a desired pattern on the surface A and the surface B on the blackening layers 13A and 13B can be performed. The etching step for supplying the etching liquid onto the surface A and the surface B on the blackening layers 13A and 13B, that is, the surface on which the resist is disposed, can be performed.

The pattern to be formed in the etching step is not particularly limited, and any shape can be used. For example, the conductive substrate 10A shown in Fig. 1A includes a plurality of straight lines, jagged lines (zigzag lines), and the like with respect to the copper layer 12, the blackening layer 13 A pattern can be formed.

In the case of the conductive substrate 10B shown in Fig. 1B, a pattern can be formed to be a mesh-shaped wiring in the copper layer 12A and the copper layer 12B. In this case, the blackening layer 13A is preferably patterned to have the same shape as the copper layer 12A and the blackening layer 13B to have the same shape as the copper layer 12B.

In addition, a lamination step of patterning the copper layer 12 or the like with respect to the above-described conductive substrate 10A in the patterning step and then laminating two or more patterned conductive substrates may be performed. In the case of laminating, for example, a laminated conductive substrate provided with mesh-shaped wiring lines may be obtained by laminating copper substrate patterns of the respective conductive substrates so as to cross each other.

The method of fixing two or more conductive substrates stacked is not particularly limited, but can be fixed with an adhesive, for example.

The conductive substrate obtained by the conductive substrate manufacturing method of the present embodiment has a structure in which a blackening layer is laminated on a copper layer formed on at least one surface of a transparent substrate. Further, since the blackening layer is formed by using the blackening plating solution described above, the blackening layer can be easily patterned into a desired shape when the copper layer and the blackening layer are patterned by etching.

In addition, the blackening layer included in the conductive substrate obtained by the conductive substrate manufacturing method of the present embodiment can be a conductive substrate in which the reflection of light is suppressed sufficiently on the surface of the copper layer to suppress the reflectance. Thus, for example, when used for a touch panel or the like, the visibility of the display can be improved.

Further, since the blackening layer can be formed by the wet process using the above-described blackening plating solution, the conductive substrate can be produced with good productivity as compared with the case where the blackening layer is formed by using the conventional dry method.

Example

Hereinafter, specific examples and comparative examples will be described, but the present invention is not limited to these examples.

(Assessment Methods)

First, the evaluation method of the obtained conductive substrate will be described.

(One) reflectivity

The measurement was carried out by installing a reflectance measuring unit on an ultraviolet visible spectrophotometer (manufactured by Shimadzu Corporation, model: UV-2600).

As described later, in each of the experimental examples, a conductive substrate having the structure shown in Fig. 1A was produced. Thus, the reflectance was measured with respect to the surface (A) of the blackening layer 13 of the conductive substrate 10A shown in Fig. 1A by setting the light having a wavelength of 400 nm to 700 nm at an incident angle of 5 deg. The average value of the reflectance was determined as the reflectance (average reflectance) of the conductive substrate.

 (2) Etching characteristics

First, in the following Experimental Example, dry film resist (Hitachi Kasei, RY3310) was bonded to the surface of the blackening layer of the obtained conductive substrate by the lamination method. Then, ultraviolet exposure was carried out through a photomask, and the resist was dissolved by a 1% aqueous sodium carbonate solution to be developed. Thus, a sample having a pattern with a different resist width by 0.5 占 퐉 in a range of 3.0 占 퐉 to 10.0 占 퐉 was produced. That is, 15 types of line patterns having resist widths of 3.0 탆, 3.5 탆, 4.0 탆, 9.5 탆, 10.0 탆, and 0.5 탆 each were formed.

Subsequently, the sample was immersed in an etching solution at 30 캜 consisting of 10% by weight of sulfuric acid and 3% by weight of hydrogen peroxide for 40 seconds, and then the dry film resist was peeled off with an aqueous solution of sodium hydroxide.

The obtained sample was observed with a 200-times microscope to find the minimum value of the wiring width of the metal wiring remaining on the conductive substrate. On the other hand, the metal wiring herein includes a linear patterned blackening layer having a wiring width corresponding to the resist width, and a copper layer or wiring.

The smaller the minimum value of the wiring width of the metal wiring remaining on the conductive substrate after the resist is peeled off means that the reactivity of the etching solution between the copper layer and the blackening layer is closer to the same value and the minimum wiring width of the remaining metal wiring is 10 m or less In this case, it is evaluated as " Good " In the case where a metal wiring having a wiring width of 10 mu m was not formed, the evaluation was evaluated as " x "

(Sample preparation conditions)

In each of the following experimental examples, a conductive substrate was produced under the conditions described below and evaluated by the above-described evaluation method.

Experimental Examples 1 to 21 are Examples, and Experimental Examples 22 to 25 are Comparative Examples.

[Experimental Example 1]

(One) Blackening plating solution

In Experimental Example 1, a blackening plating solution containing nickel ions, copper ions, amide sulfuric acid and sodium hydroxide was prepared. On the other hand, nickel sulfate hexahydrate and copper sulfate pentahydrate were added to the blackening plating solution to supply nickel ions and copper ions.

Thus, each component was added and prepared so that the nickel ion concentration in the blackening plating layer was 2.0 g / l, the copper ion concentration was 0.005 g / l, and the amide sulfuric acid concentration was 11 g / l.

Further, an aqueous solution of sodium hydroxide was added to the blackening solution to adjust the pH of the blackening solution to 5.0.

(2) Conductive substrate

(Copper layer forming step)

A copper layer was formed on one side of a long transparent polyethylene terephthalate resin (PET) transparent substrate having a length of 100 m, a width of 500 mm and a thickness of 100 m. On the other hand, the total light transmittance of the transparent substrate made of a polyethylene terephthalate resin used as a transparent substrate was evaluated by the method specified in JIS K 7361-1, and it was 97%.

In the copper layer forming step, a copper thin film layer forming step and a copper plating layer forming step were performed.

First, the copper foil layer forming process will be described.

In the copper thin film layer forming step, the above-described transparent substrate was used as a substrate, and a copper thin film layer was formed on one side of the transparent substrate.

In the copper thin film layer forming step, the above-mentioned transparent substrate from which water was removed by heating to 60 deg. C in advance was placed in the chamber of the sputtering apparatus.

Subsequently, the inside of the chamber was evacuated to 1 x 10 < ^-3 > Pa and argon gas was introduced to set the chamber inner pressure to 1.3 Pa.

Electric power was supplied to the copper target previously set on the cathode of the sputtering apparatus to form a copper thin film layer having a thickness of 0.2 占 퐉 on one surface of the transparent substrate.

Then, a copper plating layer was formed in the copper plating layer forming step. The copper plating layer was formed by electroplating so that the thickness of the copper plating layer was 0.3 mu m.

The copper thin film layer forming step and the copper plating layer forming step described above were carried out to form a copper layer having a thickness of 0.5 mu m as the copper layer.

A substrate formed with a copper layer having a thickness of 0.5 mu m on a transparent substrate prepared in the copper layer forming step was immersed in sulfuric acid of 20 g / l for 30 seconds and washed, and then the following blackening layer forming step was carried out.

(Blackening layer forming step)

In the blackening layer forming step, a blackening layer was formed on one side of the copper layer by the electrolytic plating method using the blackening plating solution of the present experimental example described above. On the other hand, in the blackening layer forming step, the blackening layer was formed by electrolytic plating under the condition that the temperature of the blackening plating liquid was 40 캜, the current density was 0.2 A / dm ² , and the plating time was 100 seconds.

The thickness of the formed blackening layer was 70 nm.

The above-described reflectance and etching characteristic evaluation were carried out on the conductive substrate obtained by the above process. The results are shown in Tables 2 and 3. Table 2 shows the evaluation results of the etching characteristics, and Table 3 shows the evaluation results of the reflectance.

Table 2 and Table 3 show the results of the respective experimental examples at positions corresponding to the numbers of the experimental examples shown in Table 1. [ For example, in Table 1, the results of Experimental Example 1 are shown in Tables 2 and 3 at a point where the nickel ion concentration is 2.0 g / l and the copper ion concentration is 0.005 g / l, which is shown in Experimental Example 1.

[Experimental Examples 2 to 24]

Blackening plating solutions were prepared in the same manner as in Experimental Example 1 except that the nickel ion concentration and the copper ion concentration in the blackening plating solution were changed to the values shown in Table 1 for each experimental example.

On the other hand, for example, in the case of Experimental Example 2, the nickel ion concentration is 3.0 g / l and the copper ion concentration is 0.005 g / l.

A conductive substrate was prepared and evaluated in the same manner as in Experimental Example 1 except that the blackening plating liquid prepared in each of the Experimental Examples was used for forming the blackening layer.

The results are shown in Tables 2 and 3.

[Experimental Example 25]

A blackening plating solution was prepared in the same manner as in Experimental Example 8, except that ammonia water was used instead of sodium hydroxide in preparing the blackening plating solution.

Specifically, a blackening plating solution containing nickel ions, copper ions, amide sulfuric acid, and ammonia was prepared.

Each component was added to the blackening plating liquid so that the concentration of nickel ion was 9.9 g / l, the concentration of copper ion was 0.05 g / l, and the concentration of amide sulfuric acid was 11 g / l.

Further, ammonia water was added to the blackening solution to adjust the pH of the blackening solution to 5.0.

Then, a conductive substrate was prepared and evaluated in the same manner as in Experimental Example 1, except that the blackening plating liquid was used in forming the blackening layer.

As a result, it was evaluated that the etching property was?, But the reflectance was 55.1%.

The conductive substrate on which the blackening layer was formed by using the blackening plating solutions of Experimental Examples 1 to 21 including nickel ions, copper ions, and a pH adjuster and the pH adjuster was an alkali metal hydroxide, It was confirmed that the minimum value of the wiring width was 10 mu m or less. Thus, it has been confirmed that, in a conductive substrate having a blackening layer formed by using these blackening plating solutions, the blackening layer can be patterned into a desired shape when it is etched together with the copper layer. In addition, it was confirmed that the average reflectance (reflectance) of light having a wavelength of 400 nm or more and 700 nm or less was 55.0% or less.

On the other hand, it was confirmed that the metal wiring patterns with the wiring width of 10 mu m remained in the comparative examples 22 to 24. Therefore, it has been confirmed that it is difficult to pattern the blackening layer into a desired shape when the blackening layer is formed using these blackening plating liquids and etched together with the copper layer.

In addition, it was confirmed that the minimum value of the wiring width in the metal wiring pattern remaining after etching was 10 占 퐉 or less in the conductive substrate on which the blackening layer was formed using the blackening plating liquid of Experimental Example 25 as a comparative example. Therefore, it has been confirmed that, in the case of a conductive substrate having a blackening layer formed by using these blackening plating solutions, when the blackening layer is etched together with the copper layer, it can be patterned into a desired shape. However, it was confirmed that the average reflectance (reflectance) of light having a wavelength of 400 nm or more and 700 nm or less was 55.1%, which is very high. The blackening plating solution of Experimental Example 25 was a blackening plating solution having the same constitution as Experimental Example 8 except that ammonia water was used instead of sodium hydroxide. In the case of a conductive substrate having a blackening layer formed by using the blackening plating solution of Experimental Example 8, 4.3%, which is much lower than that of Experimental Example 25. Thus, by using an alkali metal hydroxide as a pH adjusting agent for the blackening plating solution, it is possible to suppress the average value of the reflectance (reflectance) of light having a wavelength of 400 nm or more and 700 nm or less in the conductive substrate formed by using the blackening plating solution .

Although the blackening plating solution and the method of manufacturing the conductive substrate have been described in the above embodiments and the examples, the present invention is not limited to the above embodiments and examples. Various changes and modifications may be made without departing from the scope of the present invention described in the claims.

This application is based upon and claims the benefit of priority under Japanese Patent Application No. 2016-016598, filed on January 29, 2016, the entire contents of which is incorporated herein by reference.

Claims (4)

Nickel ions, copper ions, and pH adjusting agents,
Wherein the pH adjuster is an alkali metal hydroxide. The method according to claim 1,
Wherein the pH adjusting agent is at least one selected from sodium hydroxide and potassium hydroxide. 3. The method according to claim 1 or 2,
a pH of not less than 4.0 and not more than 5.2,
A blackening plating solution having a nickel ion concentration of 2.0 g / l or more and 20.0 g / l or less and a copper ion concentration of 0.005 g / l or more and 1.02 g / l or less. A copper layer forming step of forming a copper layer on at least one side of the transparent substrate;
And a blackening layer forming step of forming a blackening layer on the copper layer by using the blackening plating solution according to any one of claims 1 to 3.

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