JP6806093B2 - Blackening plating solution, manufacturing method of conductive substrate - Google Patents

Description

The present invention relates to a blackening plating solution and a method for producing a conductive substrate.

Capacitive touch panels convert information about the position of nearby objects on the panel surface into electrical signals by detecting changes in capacitance caused by objects close to the panel surface. Since the conductive substrate used for the capacitive touch panel is installed on the surface of the display, it is required that the material of the conductive layer of the conductive substrate has low reflectance and is difficult to see.

Therefore, as the material of the conductive layer used for the capacitance type touch panel, a material having low reflectance and difficult to see is used, and wiring is formed on a transparent substrate or a transparent film.

For example, Patent Document 1 discloses a transparent conductive film including a polymer film and a transparent conductive film made of a metal oxide provided on the polymer film by a vapor deposition method, as a transparent conductive film made of a metal oxide. It is disclosed to use an indium oxide-tin oxide (ITO) film.

By the way, in recent years, the screen size of a display provided with a touch panel has been increasing, and in response to this, a large area of a conductive substrate such as a transparent conductive film for a touch panel is required. However, since ITO has a high electric resistance value, there is a problem that it cannot cope with a large area of the conductive substrate.

Therefore, 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 lowered due to reflection. For this reason, a conductive substrate in which a layer made of a black material is formed on the surface of the conductive layer by a dry method is being studied.

However, it takes time to sufficiently blacken the surface of the conductive layer by the dry method, and the productivity is low.

Therefore, the inventors of the present invention have considered performing a blackening treatment by a wet method because it does not require a vacuum environment as required by the dry method, can simplify the equipment, and is excellent in productivity. It was. Specifically, it has been studied to form a blackened layer by a wet method using a plating solution containing Ni and Zn as main components.

Japanese Patent Application Laid-Open No. 2003-151358

However, when a blackening treatment for forming a blackening layer is performed by a wet method, that is, a wet plating method using a plating solution containing Ni and Zn as main components, the blackening layer formed is formed as a conductive layer. In some cases, the reactivity with the etching solution was higher than that of the copper layer. Then, when a conductive substrate having a desired wiring pattern is produced, a copper layer as a conductive layer and a blackening layer are formed and then patterned by etching. Due to the difference in reactivity with the blackened layer, it may be difficult to pattern the blackened layer into a desired shape.

In view of the above problems of the prior art, one aspect of the present invention is to provide a blackening plating solution capable of forming a blackening layer that can be patterned into a desired shape when etched together with a copper layer. And.

In order to solve the above problems, in one aspect of the present invention,
Contains nickel ions, copper ions, and amidosulfate ,
pH is Ri der 4.0 or 5.8 or less, the copper ion concentration provides a blackening plating solution Ru Der below 0.005 g / l or more 0.20 g / l.

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

Sectional drawing of the conductive substrate which concerns on embodiment of this invention. Sectional drawing of the conductive substrate which concerns on embodiment of this invention. Sectional drawing of the conductive substrate which concerns on embodiment of this invention. Sectional drawing of the conductive substrate which concerns on embodiment of this invention. Top view of a conductive substrate provided with mesh-like wiring according to an embodiment of the present invention. FIG. 3 is a cross-sectional view taken along the line AA'of FIG. FIG. 3 is a cross-sectional view taken along the line AA'of FIG.

Hereinafter, an embodiment of the blackening plating solution and the conductive substrate of the present invention will be described.
(Black plating solution)
The blackening plating solution of the present embodiment contains nickel ions and copper ions, and can have a pH of 4.0 or more and 5.8 or less.

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

Then, while proceeding with the study on the blackening plating solution, the inventors of the present invention suppress the reactivity of the blackening layer with the etching solution by forming the blackening layer as a layer containing nickel and copper. It was found that the desired shape can be obtained even when the copper layer is etched at the same time. It was also found that the blackening layer can have a color capable of suppressing the reflection of light on the surface of the copper layer by containing nickel and copper. The desired shape when the copper layer and the blackening layer are simultaneously etched means, for example, a shape or pattern including wiring having a wiring width of 10 μm 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 metal components, and the blackening plating solution of the present embodiment is nickel ions and copper ions. And can be contained.

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

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, and more preferably 15.0 g / l or less, for example. By setting the nickel ion concentration in the blackening plating solution to 20.0 g / l or less, it is possible to prevent the nickel component in the formed blackening layer from becoming excessive, and the surface of the blackening layer is bright nickel. This is because it is possible to prevent the surface from becoming a plating-like surface and suppress the reflectance of the conductive substrate.

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

The upper limit of the copper ion concentration in the blackening plating solution is not particularly limited, but is preferably 1.02 g / l or less, and more preferably 0.5 g / l or less, for example. By setting the copper ion concentration in the blackening plating solution to 1.02 g / l or less, it is possible to prevent the formed blackening layer from becoming too reactive with the etching solution, and to make the blackening layer copper. This is because the color is particularly suitable for suppressing the reflection of light on the layer surface, and the reflectance of the conductive substrate can be suppressed.

When preparing the blackening plating solution, the method of supplying nickel ions and copper ions is not particularly limited, and for example, it can be supplied in the form of a salt. For example, sulfamate and sulfate can be preferably used. The type of salt may be the same type for each metal element, and different types of salts may be used at the same time. Specifically, for example, a blackened plating solution can be prepared using the same type of salt as nickel sulfate and copper sulfate. It is also possible to prepare a blackened plating solution by simultaneously using different kinds of salts such as nickel sulfate and copper sulfamate.

The blackening plating solution of the present embodiment may further contain amidosulfate that functions as a complexing agent in addition to nickel ions and copper ions. By containing amidosulfuric acid, a blackening layer having a color particularly suitable for suppressing light reflection on the surface of the copper layer can be obtained.

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

For example, the concentration of amidosulfate in the blackening plating solution is not particularly limited, but is preferably 1 g / l or more and 50 g / l or less, and more preferably 5 g / l or more and 20 g / l or less. This is because by setting the concentration of amidosulfate to 1 g / l or more, the blackened layer has a color particularly suitable for suppressing the reflection of light on the surface of the copper layer, and the reflectance of the conductive substrate can be suppressed. Is. Further, even if more than 50 g / l of amide sulfuric acid is added in excess, the effect of suppressing the reflectance of the conductive substrate is not significantly changed. Therefore, it is preferably 50 g / l or less as described above.

The pH of the blackened plating solution of the present embodiment can be set to, for example, 4.0 or more and 5.8 or less.

This is because by setting the pH of the blackened plating solution to 4.0 or higher, it is more reliable to suppress the occurrence of color unevenness in the blackened layer when the blackened layer is formed by using the blackened plating solution. This is because it is possible to form a blackening layer having a color that can particularly suppress the reflection of light. Further, by setting the pH of the blackening plating solution to 5.8 or less, particularly the pH to 5.3 or less, it is possible to suppress the precipitation of a part of the components of the blackening plating solution.

Since the pH of the blackened plating solution is within the above range, the blackened plating solution of the present embodiment can contain, for example, an alkaline substance. Examples of the alkaline substance include ammonia (ammonia water) and alkali metal hydroxides such as potassium hydroxide, sodium hydroxide and lithium hydroxide.

Since the alkaline substance functions as a pH adjuster as described above, the blackening plating solution of the present embodiment preferably contains the alkaline substance so that the pH is within the above range.

The blackening plating solution of the present embodiment may contain any component other than the components described so far. Examples of the components that can be arbitrarily contained include a pit inhibitor for nickel plating. Examples of the pit inhibitor for nickel plating include Pitless S (trade name) manufactured by Nihon Kagaku Sangyo Co., Ltd. and Nickel Gleam 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 etched together with the copper layer.

Further, the blackening plating solution of the present embodiment can be suitably used when forming a blackening layer capable of sufficiently suppressing light reflection on the copper layer surface of the conductive substrate. Further, by using the blackening plating solution of the present embodiment, the blackening layer can be formed by a wet method such as an electrolytic plating method, so that it can be compared with the blackening layer which has been conventionally formed by a dry method. Therefore, the blackening layer can be formed with good productivity.
(Conductive substrate)
Next, a configuration 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 includes a transparent base material, a copper layer arranged on at least one surface of the transparent base material, and a blackening layer formed on the copper layer using a blackening plating solution. Can have.

The conductive substrate in the present embodiment is a substrate having a copper layer and a blackening layer on the surface of a transparent substrate before the copper layer or the like is patterned, and a substrate in which the copper layer or the like is patterned, that is, , Including wiring board.

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

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

As the material of the resin substrate that transmits visible light, for example, resins such as polyamide resin, polyethylene terephthalate resin, polyethylene naphthalate resin, cycloolefin resin, polyimide resin, and polycarbonate resin can be preferably used. In particular, PET (polyethylene terephthalate), COP (cycloolefin polymer), PEN (polyethylene naphthalate), polyamide, polyimide, polycarbonate and the like can be more preferably used as the material of the resin substrate that transmits visible light.

The thickness of the transparent base material is not particularly limited, and can be arbitrarily selected according to the strength, capacitance, light transmittance, etc. required for a conductive substrate. The thickness of the transparent base material can be, for example, 10 μm or more and 200 μm or less. In particular, when used in a touch panel application, the thickness of the transparent base material is preferably 20 μm or more and 120 μm or less, and more preferably 20 μm or more and 100 μm or less. When used for a touch panel, for example, especially in an application where it is required to reduce the thickness of the entire display, the thickness of the transparent base material is preferably 20 μm or more and 50 μm or less.

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

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 for forming the copper layer on the transparent base material is not particularly limited, but it is preferable not to arrange an adhesive between the transparent base material and the copper layer in order not to reduce the light transmittance. That is, the copper layer is preferably formed directly on at least one surface of the transparent substrate. When the adhesion layer is arranged between the transparent base material and the copper layer as described later, it is preferable that the copper layer is directly formed on the upper surface of the adhesion layer.

Since the copper layer is directly formed on the upper surface of the transparent base material or the like, the copper layer preferably 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 can be formed on a transparent substrate by a dry plating method, and the copper thin film layer can be used as a copper layer. As a result, the copper layer can be directly formed on the transparent base material without using an adhesive. As the dry plating method, for example, a sputtering method, a vapor deposition method, an ion plating method, or the like can be preferably used.

In addition, when increasing the thickness of the copper layer, the copper thin film layer and the copper plating layer are formed by forming the copper plating layer by an electroplating method, which is a kind of wet plating method, using the copper thin film layer as a feeding layer. It can also be a copper layer to have. Since the copper layer has the copper thin film layer and the copper plating layer, the copper layer can be directly formed on the transparent base material without using an adhesive in this case as well.

The thickness of the copper layer is not particularly limited, and when the copper layer is used as the wiring, it can be arbitrarily selected according to the magnitude of the current supplied to the wiring, the wiring width, and the like.

However, when the copper layer becomes thick, side etching is likely to occur because etching takes time when etching is performed to form a wiring pattern, which may cause problems such as difficulty in forming fine wires. Therefore, the thickness of the copper layer is preferably 5 μm or less, and more preferably 3 μm or less.

Further, from the viewpoint of lowering the resistance value of the conductive substrate and enabling sufficient current to be supplied, for example, the copper layer preferably has a thickness of 50 nm or more, more preferably 60 nm or more, and more preferably 150 nm. The above is more preferable.

When the copper layer has the copper thin film layer and the copper plating layer as described above, the total of the thickness of the copper thin film layer and the thickness of the copper plating layer is preferably in the above range.

The thickness of the copper thin film layer is not particularly limited in any case where the copper layer is composed of the copper thin film layer or has the copper thin film layer and the copper plating layer, but is, for example, 50 nm or more and 500 nm. The following is preferable.

The copper layer can be used as wiring, for example, by patterning it into a desired wiring pattern as described later. Since the copper layer can have a lower electric resistance value than ITO which has been conventionally used as a 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 blackened layer can be formed by using the blackened plating solution described above. Therefore, for example, after forming the copper layer, it can be formed on the upper surface of the copper layer by a wet method such as an electrolytic plating method.

Since the blackening plating solution has already been described, the description thereof will be omitted here.

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

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

When the blackening layer is formed with the blackening plating solution described above, the blackening layer can be a layer containing nickel and copper. In addition, components derived from various additive components contained in the blackened plating solution described above can also be contained.

Further, the conductive substrate may be provided with any layer other than the above-mentioned transparent base material, copper layer and blackening layer. For example, an adhesion layer can be provided.

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

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

Therefore, in the conductive substrate of the present embodiment, in order to improve the adhesion between the transparent base material and the copper layer, the adhesion layer can be arranged on the transparent base material. That is, a conductive substrate having an adhesion layer between the transparent base material and the copper layer can also be used.

By arranging the adhesion layer between the transparent base material and the copper layer, the adhesion between the transparent base material and the copper layer can be enhanced, and the peeling of the copper layer from the transparent base material can be suppressed.

In addition, the adhesion layer can also function as a blackening layer. Therefore, it is possible to suppress the reflection of the light of the copper layer by the light from the lower surface side of the copper layer, that is, the transparent base material side.

The material constituting the adhesion layer is not particularly limited, and the adhesion to the transparent base material and the copper layer, the required degree of suppression of light reflection on the surface of the copper layer, and the use of a conductive substrate are used. It can be arbitrarily selected according to the degree of stability with respect to the environment (for example, humidity and temperature).

The adhesion layer preferably contains, for example, at least one metal selected from Ni, Zn, Mo, Ta, Ti, V, Cr, Fe, Co, W, Cu, Sn, and Mn. The adhesion layer can also further contain one or more elements selected from carbon, oxygen, hydrogen and nitrogen.

The adhesion layer may also contain a metal alloy containing at least two or more 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 contain one or more elements selected from carbon, oxygen, hydrogen and nitrogen. At this time, the Cu—Ti—Fe alloy is a metal alloy containing at least two or more metals selected from Ni, Zn, Mo, Ta, Ti, V, Cr, Fe, Co, W, Cu, Sn, and Mn. Alternatively, Cu—Ni—Fe alloys, Ni—Cu alloys, Ni—Zn alloys, Ni—Ti alloys, Ni—W alloys, Ni—Cr alloys, and Ni—Cu—Cr alloys can be preferably used.

The method for 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, it is more preferable to use the sputtering method because the film thickness can be easily controlled. As described above, one or more elements selected from carbon, oxygen, hydrogen, and nitrogen can be added to the adhesion layer, and in this case, the reactive sputtering method can be more preferably used.

When the adhesion layer contains one or more elements selected from carbon, oxygen, hydrogen, and nitrogen, one or more elements selected from carbon, oxygen, hydrogen, and nitrogen are included in the atmosphere when the adhesion layer is formed. By adding a gas containing the above, it can be added to the adhesion layer. For example, carbon monoxide gas and / or carbon dioxide gas when carbon is added to the adhesion layer, oxygen gas when oxygen is added, hydrogen gas and / or water when hydrogen is added, When nitrogen is added, nitrogen gas can be added to the atmosphere at the time of dry plating.

A gas containing one or more elements selected from carbon, oxygen, hydrogen, and nitrogen is preferably added to the inert gas to be an atmospheric gas for dry plating. The inert gas is not particularly limited, but for example, argon can be preferably used.

By forming the adhesion layer by the dry plating method as described above, the adhesion between the transparent base material and the adhesion layer can be improved. Since the adhesive layer can contain, for example, a metal as a main component, it has high adhesion to the copper layer. Therefore, by arranging the adhesion layer between the transparent base material and the copper layer, peeling of the copper layer can be suppressed.

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

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

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

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

As described above, the conductive substrate of the present embodiment can have a transparent base material, a copper layer, and a blackening layer. Further, it is also possible to optionally have a layer such as an adhesion layer.

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

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

Specifically, for example, as in the conductive substrate 10A shown in FIG. 1A, the copper layer 12 and the blackening layer 13 can be laminated layer by layer on one surface 11a side of the transparent substrate 11. it can. Further, as in the conductive substrate 10B shown in FIG. 1B, copper layers 12A and 12B and black are formed on one surface 11a side of the transparent substrate 11 and the other surface (the other surface) 11b side, respectively. The chemical layers 13A and 13B can be laminated layer by layer in that order.

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

Specifically, for example, as in the conductive substrate 20A shown in FIG. 2A, the adhesion layer 14, the copper layer 12, and the blackening layer 13 are laminated in this order on one surface 11a side of the transparent substrate 11. be able to.

In this case as well, the transparent base material 11 may be configured by laminating an adhesion layer, a copper layer, and a blackening layer on both sides. Specifically, like the conductive substrate 20B shown in FIG. 2B, the adhesion layers 14A and 14B and the copper layers 12A and 12B are on one surface 11a side and the other surface 11b side of the transparent base material 11, respectively. And the blackened layers 13A and 13B can be laminated in that order.

In addition, in FIGS. 1B and 2B, when a copper layer, a blackening layer, etc. are laminated on both sides of the transparent base material, the layers laminated above and below the transparent base material 11 are symmetrical with the transparent base material 11 as a symmetrical plane. An example of the arrangement is shown, but the present invention is not limited to this form. For example, in FIG. 2B, the configuration of one surface 11a side of the transparent base material 11 is the same as the configuration of FIG. 1B, in which the copper layer 12A and the blackening layer 13A are laminated in that order without providing the adhesion layer 14A. The layers laminated on the upper and lower sides of the transparent base material 11 may have an asymmetrical structure.

By the way, in the conductive substrate of the present embodiment, by providing a copper layer and a blackening layer on the transparent substrate, the reflection of light by the copper layer is suppressed and the reflectance of the conductive substrate is suppressed. Can be done.

The degree of reflectance of the conductive substrate of the present embodiment is not particularly limited, but for example, in order to improve the visibility of the display when used as a conductive substrate for a touch panel, the reflectance is lower. Is good. For example, the average reflectance of light having a wavelength of 400 nm or more and 700 nm or less is preferably 60% or less, and more preferably 56% 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 laminated in this order on one surface 11a side of the transparent base material 11 as shown in FIG. 1A, the blackening layer 13 is irradiated with light so as to irradiate the blackening layer 13. The surface A of the surface A can be irradiated with light for measurement. In the measurement, light having a wavelength of 400 nm or more and 700 nm or less is irradiated to the blackening layer 13 of the conductive substrate as described above at intervals of, for example, 1 nm, and the average value of the measured values is taken as the reflectance of the conductive substrate. be able to.

The conductive substrate of this embodiment can be preferably used as a conductive substrate for a touch panel. In this case, the conductive substrate can be configured to include mesh-shaped wiring.

The conductive substrate provided with the mesh-like 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, a mesh-like wiring can be obtained by two-layer wiring. A specific configuration example is shown in FIG. FIG. 3 shows a view of the conductive substrate 30 provided with the mesh-shaped wiring from the upper surface side in the stacking direction of the copper layer or the like, and the transparent base material and the copper layer are patterned so that the wiring pattern can be easily understood. The description is omitted for the layers other than the wirings 31A and 31B formed by the formation. Further, the wiring 31B that can be seen through the transparent base material 11 is also shown.

The conductive substrate 30 shown in FIG. 3 has a transparent base material 11, a plurality of wirings 31A parallel to the Y-axis direction in the drawing, and wirings 31B parallel to the X-axis direction. The wirings 31A and 31B are formed by etching a copper layer, and a blackening layer (not shown) is formed on the upper surface or the lower surface of the wirings 31A and 31B. Further, the blackened layer is etched into the same shape as the wirings 31A and 31B.

The arrangement of the transparent base material 11 and the wirings 31A and 31B is not particularly limited. A configuration example of the arrangement of the transparent base material 11 and the wiring is shown in FIGS. 4A and 4B. 4A and 4B are cross-sectional views taken along the line AA'of FIG.

First, as shown in FIG. 4A, wirings 31A and 31B may be arranged on the upper and lower surfaces of the transparent base material 11, respectively. In FIG. 4A, blackening layers 32A and 32B etched in the same shape as the wiring are arranged on the upper surface of the wiring 31A and the lower surface of the wiring 31B.

Further, as shown in FIG. 4B, one set of transparent base materials 11 is used, wirings 31A and 31B are arranged on the upper and lower surfaces with one transparent base material 11 interposed therebetween, and one wiring 31B is a transparent base material. It may be arranged between eleven. Also in this case, the blackening layers 32A and 32B etched in the same shape as the wiring are arranged on the upper surfaces of the wirings 31A and 31B. As described above, an adhesion layer may be provided in addition to the copper layer and the blackening layer. Therefore, in either case of FIGS. 4A and 4B, for example, an adhesion layer can be provided between the wiring 31A and / or the wiring 31B and the transparent base material 11. When the adhesion layer is provided, 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-like wiring shown in FIGS. 3 and 4A is, for example, conductive having copper layers 12A and 12B and blackening layers 13A and 13B on both sides of the transparent base material 11 as shown in FIG. 1B. It can be formed from a sex substrate.

Explaining the case of forming using the conductive substrate of FIG. 1B as an example, first, the copper layer 12A and the blackening layer 13A on the one side 11a side of the transparent base material 11 are parallel to each other in the Y-axis direction in FIG. 1B. Etching is performed so that a plurality of linear patterns are arranged at predetermined intervals along the X-axis direction. The X-axis direction in FIG. 1B means a direction parallel to the width direction of each layer. Further, the Y-axis direction in FIG. 1B means a direction perpendicular to the paper surface in FIG. 1B.

Then, a plurality of linear patterns parallel to the X-axis direction in FIG. 1B form the copper layer 12B and the blackening layer 13B on the other surface 11b side of the transparent base material 11 along the Y-axis direction at predetermined intervals. Etching is performed so that it is arranged.

By the above operation, the conductive substrate having the mesh-like wiring shown in FIGS. 3 and 4A can be formed. Both sides of the transparent base material 11 can be etched at the same time. That is, the copper layers 12A and 12B and the blackening layers 13A and 13B may be etched at the same time. Further, in FIG. 4A, the conductive substrate having an adhesion layer patterned between the wirings 31A and 31B and the transparent base material 11 in the same shape as the wirings 31A and 31B is the conductive substrate shown in FIG. 2B. It can be produced by etching in the same manner using.

The conductive substrate having the mesh-like wiring shown in FIG. 3 can also be formed by using two conductive substrates shown in FIGS. 1A or 2A. Explaining the case where two conductive substrates of FIG. 1A are used as an example, a plurality of copper layers 12 and blackening layers 13 are formed parallel to the X-axis direction for each of the two conductive substrates shown in FIG. 1A. Etching is performed so that the linear patterns of the above are arranged along the Y-axis direction at predetermined intervals. Then, the two conductive substrates are laminated so that the linear patterns formed on the conductive substrates by the etching process are oriented so as to intersect with each other to obtain a conductive substrate having mesh-like wiring. be able to. The surface to be bonded when the two conductive substrates are bonded 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 in which the copper layer 12 and the like are not laminated are bonded together so as to have the structure shown in FIG. 4B. You can also do it.

Further, for example, the other surfaces 11b in FIG. 1A in which the copper layers 12 and the like of the transparent base material 11 are not laminated may be bonded to each other so that the cross section has the structure shown in FIG. 4A.

In FIGS. 4A and 4B, the conductive substrate having an adhesion layer patterned between the wirings 31A and 31B and the transparent base material 11 in the same shape as the wirings 31A and 31B is shown in FIG. 1A. It can be manufactured by using the conductive substrate shown in FIG. 2A instead of the conductive substrate.

The width of the wiring and the distance between the wirings in the conductive substrate having the mesh-shaped wirings shown in FIGS. 3, 4A and 4B are not particularly limited, and are, for example, depending on the amount of current flowing through the wirings. You can choose.

However, the conductive substrate of the present embodiment has a blackening layer formed by using the blackening plating solution described above, and the blackening layer and the copper layer are simultaneously etched and patterned. Even in this case, the blackening layer and the copper layer can be patterned into a desired shape. Specifically, for example, a wiring having a wiring width of 10 μm or less can be formed. Therefore, the conductive substrate of the present embodiment preferably includes wiring having a wiring width of 10 μm or less. The lower limit of the wiring width is not particularly limited, but may be, for example, 3 μm or more.

Further, in FIGS. 3, 4A and 4B, examples of forming a mesh-shaped wiring (wiring pattern) by combining linear wirings are shown, but the wiring pattern is not limited to this. The wiring constituting the above can be of any shape. For example, the shape of the wiring forming the mesh-like wiring pattern so as not to generate moire (interference fringes) with the image on the display can be made into various shapes such as a jaggedly bent line (zigzag straight line).

Such a conductive substrate having a mesh-like wiring composed of two layers of wiring can be preferably used as, for example, a conductive substrate for a projected capacitance type touch panel.

The conductive substrate of the present embodiment described above 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 formed when the copper layer and the blackening layer are patterned by etching as described above. It can be patterned into a desired shape.

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

Furthermore, since the blackened layer can be formed by the wet method using the blackened plating solution described above, the conductive substrate can be produced with higher productivity than the case where the blackened layer is formed by using the conventional dry method. Can be produced.
(Manufacturing method of conductive substrate)
Next, a configuration example of the method for manufacturing the conductive substrate of the present embodiment will be described.

The method for manufacturing a conductive substrate of this embodiment can have the following steps.
A copper layer forming step of forming a copper layer on at least one surface of a transparent substrate.
A blackening layer forming step of forming a blackening layer on a copper layer using a blackening plating solution.

As the blackening plating solution, the above-mentioned blackening plating solution, specifically, a blackening plating solution containing nickel ions and copper ions and having a pH of 4.0 or more and 5.8 or less may be used. it can.

The method for manufacturing the conductive substrate of the present embodiment will be specifically described below.

The conductive substrate described above can be suitably manufactured by the method for manufacturing a conductive substrate of the present embodiment. Therefore, except for the points described below, the configuration can be the same as that of the conductive substrate described above, and some description thereof will be omitted.

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

Then, as described above, the copper layer preferably has a copper thin film layer. Further, the copper layer may have a copper thin film layer and a copper plating layer. Therefore, the copper layer forming step can include, for example, a step of forming a copper thin film layer by a dry plating method. The copper layer forming step includes 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 a kind of wet plating method using the copper thin film layer as a feeding layer. May have.

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. As the vapor deposition method, a vacuum vapor deposition method can be preferably used. As the dry plating method used in the step of forming the copper thin film layer, it is more preferable to use the sputtering method because the film thickness can be easily controlled.

Next, the process 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 conditions of the electroplating treatment are not particularly limited, and various conditions according to the conventional method may be adopted. For example, a copper plating layer can be formed by supplying a base material having a copper thin film layer formed to a plating tank containing a copper plating solution and controlling the current density and the transport speed of the base material.

Next, the blackening layer forming step will be described.

In the blackening layer forming step, a blackening layer can be formed by using a blackening plating solution containing the above-mentioned nickel ions and copper ions and having a pH of 4.0 or more and 5.8 or less.

The blackened layer can be formed by a wet method. Specifically, for example, using a copper layer as a feeding layer, a blackening layer can be formed on the copper layer by an electrolytic plating method in a plating tank containing the blackening plating solution described above. By forming the blackening layer by the electrolytic plating method using the copper layer as the feeding layer in this way, the blackening layer can be formed on the entire surface of the copper layer opposite to the surface facing the transparent base material.

Since the blackening plating solution has already been described, the description thereof will be omitted.

In the method for manufacturing a conductive substrate of the present embodiment, any step can be further carried out in addition to the above-mentioned steps.

For example, when an adhesive layer is formed between the transparent base material and the copper layer, an adhesive layer forming step of forming the adhesive layer on the surface forming the copper layer of the transparent base material can be carried out. When the adhesion layer forming step is carried out, the copper layer forming step can be carried out after the adhesion layer forming step, and in the copper layer forming step, copper is formed on the base material in which the adhesion layer is formed on the transparent base material in this step. A thin film layer can be formed.

In the adhesion layer forming step, the film forming method of the adhesion layer is not particularly limited, but it is preferable to form a 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, it is more preferable to use the sputtering method because the film thickness can be easily controlled. As described above, one or more elements selected from carbon, oxygen, hydrogen, and nitrogen can be added to the adhesion layer, and in this case, the reactive sputtering method can be more preferably used.

The conductive substrate obtained by the method for manufacturing a conductive substrate of the present embodiment can be used for various purposes such as a touch panel. When used for various purposes, it is preferable that the copper layer and the blackening layer contained in the conductive substrate of the present embodiment are patterned. When the adhesion layer is provided, it is preferable that the adhesion layer is also patterned. The copper layer and the blackening layer, and in some cases the adhesion layer, can be patterned according to, for example, a desired wiring pattern, and the copper layer, the blackening layer, and in some cases the adhesion layer can be patterned in the same shape. It is preferable that it is made.

Therefore, the method for manufacturing a conductive substrate of the present embodiment can include a patterning step of patterning a copper layer and a blackening layer. When the adhesion layer is formed, the patterning step can be a step of patterning the adhesion layer, the copper layer, and the blackening layer.

The specific procedure of the patterning step is not particularly limited, and can be carried out by any procedure. 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 base material 11 as shown in FIG. 1A, first, a resist having a desired pattern is arranged on the surface A on the blackening layer 13. A resist placement step can be performed. Next, an etching step of supplying the etching solution to the surface A on the blackening layer 13, that is, the surface side on which the resist is arranged can be performed.

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

As the etching solution, for example, a mixed aqueous solution containing one or more selected from sulfuric acid, hydrogen peroxide (hydrogen peroxide solution), hydrochloric acid, cupric chloride, and ferric chloride can be preferably used. The content of each component in the etching solution is not particularly limited.

The etching solution can be used at room temperature, but it can also be used by heating it in order to enhance the reactivity. For example, it can be used by heating it to 40 ° C. or higher and 50 ° C. or lower.

Further, as shown in FIG. 1B, a patterning step is performed in which 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 is also patterned. it can. In this case, for example, a resist placement step of placing a resist having a desired pattern on the surface A and the surface B on the blackened layers 13A and 13B can be performed. Next, an etching step of supplying an etching solution to the surface A and the surface B on the blackening layers 13A and 13B, that is, the surface side on which the resist is arranged can be performed.

The pattern formed in the etching step is not particularly limited, and any shape can be used. For example, in the case of the conductive substrate 10A shown in FIG. 1A, a pattern is formed so that the copper layer 12 and the blackening layer 13 include a plurality of straight lines and jaggedly bent lines (zigzag straight lines) as described above. Can be done.

Further, in the case of the conductive substrate 10B shown in FIG. 1B, a pattern can be formed between the copper layer 12A and the copper layer 12B so as to form a mesh-like wiring. In this case, it is preferable that the blackening layer 13A is patterned so as to have the same shape as the copper layer 12A, and the blackening layer 13B is preferably patterned so as to have the same shape as the copper layer 12B.

Further, for example, it is also possible to carry out a laminating step of laminating two or more patterned conductive substrates after patterning a copper layer 12 or the like on the above-mentioned conductive substrate 10A in a patterning step. When laminating, for example, by laminating so that the patterns of the copper layers of each conductive substrate intersect, it is possible to obtain a laminated conductive substrate having mesh-shaped wiring.

The method of fixing the two or more laminated conductive substrates is not particularly limited, but can be fixed by, for example, an adhesive or the like.

The conductive substrate obtained by the above-mentioned method for manufacturing a conductive substrate 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. .. Since the blackening layer is formed by using the blackening plating solution described above, when the copper layer and the blackening layer are patterned by etching, the blackening layer is easily patterned into a desired shape. can do.

Further, the blackening layer contained in the conductive substrate obtained by the method for manufacturing the conductive substrate of the present embodiment shall be a conductive substrate in which the reflection of light on the surface of the copper layer is sufficiently suppressed and the reflectance is suppressed. Can be done. Therefore, the visibility of the display can be improved when used for a touch panel or the like, for example.

Furthermore, since the blackened layer can be formed by the wet method using the blackened plating solution described above, the conductive substrate can be produced with higher productivity than the case where the blackened layer is formed by using the conventional dry method. Can be produced.

Specific examples and comparative examples will be described below, but the present invention is not limited to these examples.
(Evaluation method)
First, an evaluation method of the obtained conductive substrate will be described.
(1) The reflectance was measured by installing a reflectance measurement unit on an ultraviolet-visible spectrophotometer (model: UV-2600 manufactured by Shimadzu Corporation).

As will be described later, in each experimental example, a conductive substrate having the structure shown in FIG. 1A was produced. Therefore, in the reflectance measurement, the incident angle is 5 ° and the light receiving angle is 5 ° with respect to the surface A of the blackening layer 13 of the conductive substrate 10A shown in FIG. 1A, and light having a wavelength of 400 nm or more and 700 nm or less is emitted at wavelength 1 nm intervals. The regular reflectance was measured by irradiation, and the average value was taken as the reflectance (average reflectance) of the conductive substrate.
(2) Etching Characteristics First, a dry film resist (Hitachi Kasei RY3310) was attached to the surface of the blackened layer of the conductive substrate obtained in the following experimental example by a laminating method. Then, ultraviolet exposure was performed through a photomask, and the resist was further dissolved and developed with a 1% aqueous sodium carbonate solution. As a result, a sample having a pattern in which the resist width was different every 0.5 μm was prepared in the range of 3.0 μm or more and 10.0 μm or less. That is, the resist width was 3.0 μm, 3.5 μm, 4.0 μm ... 9.5 μm, 10.0 μm, and 15 types of linear patterns different for each 0.5 μm were formed.

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

The obtained sample was observed with a microscope of 200 times, and the minimum value of the wiring width of the metal wiring remaining on the conductive substrate was determined. The metal wiring here includes a linearly patterned blackening layer having a wiring width corresponding to the resist width, and a copper layer, that is, 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, the closer the reactivity of the copper layer and the blackening layer to the etching solution is closer to the same, and the remaining metal wiring remains. When the minimum value of the wiring width of the metal wiring was 10 μm or less, it was evaluated as 〇 in Table 2 as a pass. Further, when a metal wiring having a wiring width of 10 μm could not be formed, it was evaluated as × in Table 2 as a failure.
(Sample preparation conditions)
In each of the following experimental examples, a conductive substrate was prepared under the conditions described below, and evaluation was performed by the above-mentioned evaluation method.

Experimental Examples 1 to 12 are Examples, and Experimental Examples 13 to 25 are Comparative Examples.
[Experimental Example 1]
(1) Blackening Plating Solution In Experimental Example 1, a blackening plating solution containing nickel ions, copper ions, amidosulfate, and ammonia was prepared. Nickel ions and copper ions were supplied to the blackened plating solution by adding nickel sulfate hexahydrate and copper sulfate pentahydrate.

Then, each component was added and prepared so that the concentration of nickel ions in the blackening plating solution was 8.9 g / l, the concentration of copper ions was 0.05 g / l, and the concentration of amidosulfate was 11 g / l.

Further, aqueous ammonia was added to the blackening plating solution to adjust the pH of the blackening plating solution to 4.0.
(2) Conductive substrate (copper layer forming process)
A copper layer was formed on one surface of a long transparent polyethylene terephthalate resin (PET) having a length of 100 m, a width of 500 mm, and a thickness of 100 μm. Regarding the transparent base material made of polyethylene terephthalate resin used as the transparent base material, the total light transmittance was evaluated by the method specified in JIS K 7361-1 and found to be 97%.

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

First, the copper thin film layer forming step will be described.

In the copper thin film layer forming step, the above-mentioned transparent base material was used as the base material, and the copper thin film layer was formed on one surface of the transparent base material.

In the copper thin film layer forming step, first, the above-mentioned transparent base material which was previously heated to 60 ° C. to remove water was installed in the chamber of the sputtering apparatus.

Next, after exhausting the inside of the chamber to 1 × 10 ^-3 Pa, argon gas was introduced to set the pressure inside the chamber to 1.3 Pa.

Electric power was supplied to a copper target set in advance on the cathode of the sputtering apparatus, and a copper thin film layer was formed on one surface of the transparent substrate so as to have a thickness of 0.2 μm.

Next, in the copper plating layer forming step, a copper plating layer was formed. The copper plating layer was formed by an electroplating method so that the thickness of the copper plating layer was 0.3 μm.

By carrying out the above copper thin film layer forming step and the copper plating layer forming step, a copper layer having a thickness of 0.5 μm was formed as a copper layer.

The substrate having a copper layer having a thickness of 0.5 μm formed on the transparent substrate prepared in the copper layer forming step was immersed in 20 g / l sulfuric acid for 30 seconds, washed, and then the following blackening layer forming step was carried out. ..
(Blackening layer forming process)
In the blackening layer forming step, a blackening layer was formed on one surface of the copper layer by an electrolytic plating method using the blackening plating solution of the above-mentioned experimental example. In the blackening layer forming step, electrolytic plating was performed under the conditions that the temperature of the blackening plating solution was 40 ° C., the current density was 0.2 A / dm ² , and the plating time was 100 sec, to form a blackened layer.

The film thickness of the formed blackened layer was 70 nm.

The reflectance and etching characteristics described above were evaluated for the conductive substrate obtained by the above steps. 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.
[Experimental Examples 2 to 25]
When preparing the blackened plating solution, the same as in Experimental Example 1 except that the concentration and pH of copper ions in the blackened plating solution were changed to the values shown in Table 1. A blackened plating solution was prepared.

For example, in the case of Experimental Example 2, the concentration of copper ions is 0.10 g / l and the pH is 4.0.

In addition, a conductive substrate was prepared and evaluated in the same manner as in Experimental Example 1 except that the blackened plating solution prepared in each Experimental Example was used when forming the blackened layer.

The results are shown in Tables 2 and 3.

In Tables 2 and 3, the parts corresponding to the numbers of the experimental examples shown in Table 1 show the results of each experimental example. For example, the places where the copper ion concentration shown in Table 1 as Experimental Example 2 is 0.10 g / l and the pH is 4.0 show the results of Experimental Example 2 in Tables 2 and 3.

表２に示した結果より、ニッケルイオンと、銅イオンと、を含み、ｐＨが４．０以上５．８以下である実験例１〜実験例１２の黒化めっき液を用いて黒化層を形成し、エッチング後に残った金属配線のパターンの、配線幅の最小値が１０μｍ以下となることが確認できた。従って、これらの黒化めっき液を用いて成膜した黒化層を有する導電性基板では、黒化層を銅層と共にエッチングした場合に、所望の形状にパターン化できることが確認できた。また、表３に示した結果より、実験例１〜実験例１２の黒化めっき液を用いて形成した黒化層を有する導電性基板は、波長４００ｎｍ以上７００ｎｍ以下の光の正反射率の平均値（反射率）も６０％以下であることを確認できた。

From the results shown in Table 2, the blackened layer was formed using the blackened plating solution of Experimental Examples 1 to 12 containing nickel ions and copper ions and having a pH of 4.0 or more and 5.8 or less. It was confirmed that the minimum value of the wiring width of the metal wiring pattern that was formed and remained after etching was 10 μm or less. Therefore, it was confirmed that the conductive substrate having the blackening layer formed by using these blackening plating solutions can be patterned into a desired shape when the blackening layer is etched together with the copper layer. Further, from the results shown in Table 3, the conductive substrate having the blackening layer formed by using the blackening plating solution of Experimental Examples 1 to 12 has an average specular reflectance of light having a wavelength of 400 nm or more and 700 nm or less. It was confirmed that the value (reflectance) was also 60% or less.

On the other hand, in Experimental Example 13 and Experimental Examples 18 to 20 which are comparative examples, it was confirmed that no metal wiring pattern having a wiring width of 10 μm remained after etching. Therefore, it was confirmed that it is difficult to pattern the blackened layer into a desired shape when a blackened layer is formed using these blackening plating solutions and etched together with the copper layer.

Further, in Experimental Examples 21 to 25, a precipitate was formed in the plating solution, and the blackening layer could not be formed.

In Experimental Examples 14 to 17, it was confirmed that the minimum value of the wiring width of the metal wiring pattern remaining after etching was 10 μm or less, but uneven plating occurred in the formed blackened layer. , Could not be used as a conductive substrate.

Although the method for producing the blackened plating solution and the conductive substrate has been described above in the embodiments and examples, the present invention is not limited to the above-described embodiments and examples. Various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

This application claims priority based on Japanese Patent Application No. 2016-016592 filed with the Japan Patent Office on January 29, 2016, and the entire contents of Japanese Patent Application No. 2016-016592 are included in this international application. Invite.

Claims (3)

Contains nickel ions, copper ions, and amidosulfate,
pH is Ri der 4.0 or 5.8 or less, blackening plating solution copper ion concentration Ru Der below 0.005 g / l or more 0.20 g / l. Blackening plating solution according to claim 1 nickel ion concentration is 20.0 g / l hereinafter more 2.0 g / l. A copper layer forming step of forming a copper layer on at least one surface of a transparent substrate,
A method for producing a conductive substrate, which comprises a blackening layer forming step of forming a blackening layer on the copper layer using the blackening plating solution according to claim 1 or 2 .

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