KR102611763B1 - Blackening plating solution and conductive substrate manufacturing method - Google Patents

Abstract

A blackening plating solution containing nickel ions and copper ions and having a pH of 4.0 or more and 5.8 or less is provided.

Description

Blackening plating solution and conductive substrate manufacturing method

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

A capacitive touch panel converts position information of an object approaching on the panel surface into an electrical signal by detecting changes in capacitance caused by an object approaching the panel surface. Since the conductive substrate used in the capacitive touch panel is installed on the display surface, the conductive layer material of the conductive substrate is required to have a low reflectivity and be difficult to see.

Therefore, as the material of the conductive layer used in the electrostatic capacitive touch panel, a material with low reflectivity and difficult to be seen is used, and wiring is formed on a transparent substrate or 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 formed thereon by a vapor phase film forming method, and the transparent conductive film made of a metal oxide is oxidized. The use of indium-tin oxide (ITO) membranes is disclosed.

However, in recent years, displays with touch panels have been becoming larger, and correspondingly, there is a demand for larger areas for conductive substrates such as transparent conductive films for touch panels. However, ITO had a problem in that it had a high electrical resistance value and could not respond to larger areas of conductive substrates.

Therefore, the use of metals such as copper instead of ITO as a material for the conductive layer has been considered. However, since metal has a metallic luster, there was a problem that the visibility of the display was reduced due to reflection. Therefore, a conductive substrate subjected to a blackening treatment in which a layer composed of a black material is formed on the surface of the conductive layer by a dry method has been studied.

However, it took time to sufficiently blacken the surface of the conductive layer using the dry method, resulting in low productivity.

Therefore, the inventors of the present invention have studied blackening treatment by a wet method because it does not require the vacuum environment required by the dry method, simplifies equipment, and has excellent productivity. Specifically, the formation of a blackening layer by a wet method using a plating solution containing Ni and Zn as main components has been studied.

Japanese Patent Laid-open Publication No. 2003-151358

However, when blackening treatment to form 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 more resistant to the etching solution than the copper layer formed as a conductive layer. There were cases of high reactivity. In the case of manufacturing a conductive substrate with a desired wiring pattern, the conductive copper layer and the blackening layer are formed and then patterned by etching. There were cases where it was difficult to pattern it into a shape.

In consideration of the problems of the prior art, one aspect of the present invention aims to provide a blackening plating solution that can form a blackening layer that can be patterned into a desired shape when etched together with a copper layer.

In one aspect of the present invention for solving the above problems, a blackening plating solution containing nickel ions and copper ions and having a pH of 4.0 or more and 5.8 or less is provided.

According to one aspect of the present invention, it is possible to provide a blackening plating solution that can form a blackening layer that can be patterned into a desired shape when etched 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.
Figure 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.
Figure 3 is a top view of a conductive substrate provided with mesh-shaped wiring according to an embodiment of the present invention.
FIG. 4A is a cross-sectional view taken along line AA′ of FIG. 3.
FIG. 4B is a cross-sectional view taken along line AA′ of FIG. 3.

Below, an embodiment of the blackening plating solution and conductive substrate of the present invention will be described.

(Blackening plating solution)

The blackening plating solution of this embodiment contains nickel ions and copper ions, and can have a pH of 4.0 or more and 5.8 or less.

As previously explained, for example, the blackening layer formed by the wet method using a plating solution containing Ni and Zn as main components has a higher reactivity to the etching solution than the copper layer, so when etched together with the copper layer, it can be patterned into the desired shape. It was difficult to do. Therefore, the inventors of the present invention carefully studied a blackening plating solution that can form a blackening layer that can be patterned into a desired shape when etched together with a copper layer.

Accordingly, while examining the blackening plating solution, the inventors of the present invention found that by making the blackening layer a layer containing nickel and copper, the reactivity of the blackening layer to the etching solution could be suppressed, even when etching at the same time as the copper layer. It was discovered that it could be made into any desired shape. Additionally, it was also discovered that by containing nickel and copper in the blackening layer, a color that can suppress light reflection on the surface of the copper layer can be obtained. Meanwhile, the desired shape in the case of simultaneously etching the copper layer and the blackening layer referred to here means, for example, a shape and pattern including wiring with a wiring width of 10 μm or less.

Therefore, it is preferable that the blackening plating solution of this embodiment is a plating solution that can form a layer containing nickel and copper as metal components, and the blackening plating solution of this embodiment can contain nickel ions and copper ions.

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, and more preferably 3.0 g/l or more. This is because by setting the nickel ion concentration in the blackening plating solution to 2.0 g/l or more, the blackening layer can be made into 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 for example, it is preferably 20.0 g/l or less, and more preferably 15.0 g/l or less. By setting the nickel ion concentration in the blackening plating solution to 20.0 g/l or less, this suppresses the nickel component in the formed blackening layer from becoming excessive, prevents the blackening layer surface from becoming like a glossy nickel-plated surface, and increases the reflectance of the conductive substrate. This is because it can be suppressed.

Additionally, 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. 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 of 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 appropriate. This is because even when etching the blackening layer together with the copper layer, it can be more reliably patterned into the desired shape.

The upper limit of the copper ion concentration in the blackening plating solution is not particularly limited, but for example, it is preferably 1.02 g/l or less, and more preferably 0.5 g/l or less. By setting the copper ion concentration in the blackening plating solution to 1.02 g/l or less, the reactivity of the formed blackening layer to the etching solution is suppressed from being excessively high, making the blackening layer 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 coloring it.

When preparing a blackening plating solution, the method of supplying nickel ions and copper ions is not particularly limited, and for example, they can be supplied in a salt state. For example, sulfamate, sulfate, etc. can be used appropriately as needed. Meanwhile, the type of salt may be the same type for each metal element, or different types of salts may be used simultaneously. Specifically, for example, a blackening plating solution can be prepared using the same type of salt, such as nickel sulfate or copper sulfate. In addition, for example, a blackening plating solution can be prepared by simultaneously using different types of salts, such as nickel sulfate and copper sulfamate.

The blackening plating solution of this embodiment may further contain 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 very suitable for suppressing light reflection on the surface of the copper layer can be obtained.

The content of amide sulfuric acid 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 amide sulfuric acid in the blackening plating solution is not particularly limited, but for example, it 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 amide sulfuric acid to 1 g/l or more, the blackening layer can be made into 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. In addition, even if amide sulfuric acid is added in excess of 50 g/l, the effect of suppressing the reflectance of the conductive substrate does not significantly change, so as described above, it is preferable that the amount is 50 g/l or less.

And the pH of the blackening plating solution of this embodiment can be, for example, 4.0 or more and 5.8 or less.

By setting the pH of the blackening plating solution to 4.0 or higher, the occurrence of color unevenness in the blackening layer when the blackening layer is formed using the blackening plating solution can be more reliably suppressed, and the color that can significantly suppress light reflection can be obtained. This is because a blackening layer can be formed. Additionally, by setting the pH of the blackening plating solution to 5.8 or less, especially 5.3 or less, precipitation of a part of the blackening plating solution components can be suppressed.

In order to set the pH of the blackening plating solution to the above range, the blackening plating solution of this embodiment may contain, for example, an alkaline substance. Examples of alkaline substances include alkali metal hydroxides such as ammonia (ammonia water), potassium hydroxide, sodium hydroxide, and lithium hydroxide.

And, as described above, since the alkaline substance functions as a pH adjuster, it is preferable that the blackening plating solution of this embodiment contains an alkaline substance so that the pH is within the above range.

The blackening plating solution of this embodiment may contain arbitrary components other than the components described so far. Components that can be optionally included include, for example, a pit prevention agent for nickel plating. Examples of pitting prevention agents for nickel plating include Pitless S (trade name) manufactured by Japan Chemical Industry Co., Ltd., Nickel Gleam NAW4 (brand name) manufactured by Rohm & Haas Co., Ltd., and the like.

According to the blackening plating solution of the present embodiment described above, when etched together with the copper layer, a blackening layer that can be patterned into a desired shape can be formed.

Additionally, the blackening plating solution of this embodiment can be used appropriately as needed when forming a blackening layer that can sufficiently suppress light reflection on the surface of the copper layer of the conductive substrate. In addition, by using the blackening plating solution of this embodiment, the blackening layer can be formed by a wet method such as electrolytic plating, so the blackening layer can be formed with good productivity compared to the blackening layer formed into a film by a dry method conventionally.

(Conductive substrate)

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

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

Meanwhile, the conductive substrate in this embodiment includes a substrate having a copper layer and a blackening layer on the surface of a transparent substrate before patterning the copper layer, etc., and a substrate on which the copper layer, etc. are patterned, that is, a wiring board. .

Here, 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.

Materials for the resin substrate that transmit visible light are preferably, for example, polyamide-based resin, polyethylene terephthalate-based resin, polyethylene naphthalate-based resin, cycloolefin-based resin, polyimide-based resin, and polycarbonate-based resin. Resins such as these can be used. In particular, more preferably, as a material for the resin substrate that transmits visible light, PET (polyethylene terephthalate), COP (cycloolefin polymer), PEN (polyethylene naphthalate), polyamide, polyimide, polycarbonate, etc. can be used. there is.

The thickness of the transparent substrate is not particularly limited and can be arbitrarily selected depending on the strength, capacitance, light transmittance, etc. required when using a conductive substrate. The thickness of the transparent substrate can be, for example, 10 μm or more and 200 μm or less. In particular, when used for a touch panel, the thickness of the transparent substrate is preferably 20 μm or more and 120 μm or less, and more preferably 20 μm or more and 100 μm or less. In the case of use as a touch panel, for example, especially in applications that require thinning the overall thickness of the display, the thickness of the transparent substrate is preferably 20 μm or more and 50 μm or less.

It is preferable that the total light transmittance of the transparent substrate is 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 substrate is within the above range, for example, when used for a touch panel, sufficient visibility of the display can be ensured.

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

Next, the copper layer is explained.

The method of forming the copper layer on the transparent substrate is not particularly limited, but it is preferable not to place an adhesive between the transparent substrate and the copper layer to reduce light transmittance. That is, it is preferable that the copper layer is formed directly on at least one side of the transparent substrate. Meanwhile, as will be described later, when an adhesion layer is disposed between a transparent substrate and a copper layer, it is preferable that the copper layer is 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. Additionally, 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 formed directly on the transparent substrate without using an adhesive. On the other hand, as a dry plating method, for example, sputtering method, vapor deposition method, ion plating method, etc. can be preferably used.

In addition, when increasing the film thickness of the copper layer, a copper plating layer can be formed by using the copper thin film layer as a power supply layer by electroplating, a type of wet plating method, to form a copper layer having a copper thin film layer and a copper plating layer. Since the copper layer has a copper thin film layer and a copper plating layer, even in this case, the copper layer can be formed directly on the transparent substrate without using an adhesive.

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

However, if the copper layer is thick, side etching is likely to occur because etching to form a wiring pattern takes time, which may cause problems such as making it difficult to form thin lines. Therefore, the thickness of the copper layer is preferably 5 μm or less, and more preferably 3 μm or less.

In addition, especially from the viewpoint of lowering the resistance value of the conductive substrate to enable sufficient current supply, for example, the thickness of the copper layer is preferably 50 nm or more, more preferably 60 nm or more, and even more preferably 150 nm or more. desirable.

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

In either case, whether the copper layer is composed of a copper thin film layer or has 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, for example, 50 nm or more and 500 nm or less.

The copper layer can be used as a wiring, for example, by patterning it into a desired wiring pattern, as described later. In addition, the copper layer can lower the electrical resistance value than ITO, which has been used as a conventional transparent conductive film, and therefore the electrical resistance value of the conductive substrate can be reduced by providing the copper layer.

Next, the blackening layer is explained.

The blackening layer can be formed using the blackening plating solution described above. For this purpose, 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 electrolytic plating.

Since the blackening plating solution was explained previously, the description is omitted here.

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

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

On the other hand, when forming the blackening layer into a film using the blackening plating solution described above, the blackening layer can be a layer containing nickel and copper. In addition, it may also contain components derived from various additive components included in the blackening plating solution described above.

Additionally, the conductive substrate may include any layer other than the transparent substrate, copper layer, and blackening layer described above. For example, an adhesion layer may be provided.

A configuration example of the adhesion layer will be described.

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

Therefore, in the conductive substrate of this embodiment, an adhesion layer can be disposed on the transparent substrate in order to improve the adhesion between the transparent substrate and the copper layer. In other words, it can also be used as a conductive substrate having an adhesion layer between the transparent substrate and the copper layer.

By disposing an adhesion layer between the transparent substrate and the copper layer, the adhesion between the transparent substrate and the copper layer can be improved and peeling of the copper layer from the transparent substrate can be suppressed.

Additionally, the adhesion layer can also function as a blackening layer. Thus, it becomes possible to suppress light reflection of the copper layer for light entering from the lower surface of the copper layer, that is, the transparent substrate side.

The material constituting the adhesion layer is not particularly limited, and includes the adhesion between the transparent substrate and the copper layer, the degree of suppression of light reflection required on the surface of the copper layer, and the environment in which the conductive substrate is used (e.g., humidity, temperature). It can be selected arbitrarily depending on the degree of stability, etc.

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

Additionally, the adhesion layer may include a metal alloy containing at least two types of metals selected from Ni, Zn, Mo, Ta, Ti, V, Cr, Fe, Co, W, Cu, Sn, and Mn. In this case as well, the adhesion layer may further contain one or more elements selected from carbon, oxygen, hydrogen, and nitrogen. At this time, the metal alloy containing at least two 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, Ni-Cu-Cr alloy, etc. can be used.

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

If the adhesion 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 when forming the adhesion layer. By adding it, it can be added to the adhesion layer. For example, when adding carbon to the adhesion layer, carbon monoxide gas and/or carbon dioxide gas are added, when adding oxygen, oxygen gas is added, when adding hydrogen, hydrogen gas and/or water are added, and nitrogen is added. In this case, nitrogen gas can be added to the atmosphere during dry plating.

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

As described above, by forming the adhesion layer using a dry plating method, the adhesion between the transparent substrate and the adhesion layer can be improved. Also, since the adhesion layer may contain metal as a main component, for example, it has high adhesion to the copper layer. Therefore, peeling of the copper layer can be suppressed by disposing an adhesion layer between the transparent substrate and the copper layer.

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

When the adhesion layer also functions as a blackening layer, that is, when light reflection 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 if it is made thicker than necessary, the time required for film formation and the time required for etching when forming wiring will be longer, resulting in an increase in cost. Therefore, as described above, the thickness of the adhesion layer is preferably 50 nm or less, more preferably 35 nm or less, and even more preferably 33 nm or less.

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

As described above, the conductive substrate of this embodiment may have a transparent substrate, a copper layer, and a blackening layer. Additionally, layers such as an adhesion layer may be optionally provided.

A specific configuration example will be described below using FIGS. 1A, 1B, 2A, and 2B. 1A, 1B, 2A, and 2B show examples of cross-sectional views in a plane parallel to the lamination direction of the transparent substrate, copper layer, and blackening layer of the conductive substrate of this embodiment.

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

Specifically, for example, as in the conductive substrate 10A shown in FIG. 1A, a copper layer 12 and a blackening layer 13 are laminated one by one in that order on one side 11a of the transparent substrate 11. can do. In addition, as in the conductive substrate 10B shown in FIG. 1B, copper layers 12A and 12B and blackening layers are formed on one side 11a and the other side (11b) of the transparent substrate 11, respectively. It can be stacked one layer at a time in the order of 13A, 13B).

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

Specifically, for example, as in the conductive substrate 20A shown in FIG. 2A, an adhesion layer 14, a copper layer 12, and a blackening layer 13 are formed on one side 11a of the transparent substrate 11. It can be laminated in the following order.

In this case as well, a structure may be used in which an adhesion layer, a copper layer, and a blackening layer are laminated on both sides of the transparent substrate 11. Specifically, as in the conductive substrate 20B shown in FIG. 2B, adhesion layers 14A and 14B, copper layers 12A, and 12B), blackening layers (13A, 13B) can be laminated in that order.

On the other hand, in the case where a copper layer, a blackening layer, etc. are laminated on both sides of the transparent substrate as shown in FIGS. 1B and 2B, the layers laminated on the top and bottom of the transparent substrate 11 are arranged symmetrically with the transparent substrate 11 as the plane of symmetry. Although one example is shown, it is not limited to this form. For example, in FIG. 2B, the configuration on one side 11a of the transparent substrate 11 is made up of the copper layer 12A and the blackening layer 13A without the adhesion layer 14A as in the configuration in FIG. 1B. In a sequentially laminated form, the layers laminated on top and bottom of the transparent substrate 11 may be configured in an asymmetrical manner.

However, in the conductive substrate of the present embodiment, by providing a copper layer and a blackening layer on the transparent substrate, light reflection by the copper layer can be suppressed and the reflectance of the conductive substrate can be suppressed.

There is no particular limitation on the degree of reflectance of the conductive substrate of this embodiment, but for example, in order to improve display visibility when used as a conductive substrate for a touch panel, it is better for the reflectance to be low. For example, the average reflectance of light with a wavelength of 400 nm to 700 nm is preferably 60% or less, and more preferably 56% or less.

The reflectance can be measured by irradiating light to the blackening layer of the conductive substrate. Specifically, for example, when the copper layer 12 and the blackening layer 13 are laminated in that order on one side 11a of the transparent substrate 11 as shown in FIG. 1A, the blackening layer 13 It can be measured by irradiating light to the surface A of the blackening layer 13 so as to irradiate light. In the measurement, light with a wavelength of 400 nm or more and 700 nm or less is irradiated, for example, at wavelength intervals of 1 nm, to the blackening layer 13 of the conductive substrate as described above, and the average of the measured values is taken as the average value of the conductive substrate. It can be done with a reflectance of .

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

A conductive substrate with mesh-shaped wiring can be obtained by etching the copper layer and blackening layer of the conductive substrate of this embodiment described so far.

For example, mesh-shaped wiring can be achieved by two layers of wiring. A specific configuration example is shown in Figure 3. Figure 3 shows a view of the conductive substrate 30 with mesh-shaped wiring as seen from the upper surface in the direction in which copper layers, etc. are laminated. In order to make the wiring pattern easy to understand, the wiring 31A, 31B is formed by patterning the transparent substrate and the copper layer. ) The description of layers other than this is omitted. Additionally, the wiring 31B visible 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 in the drawing, and a wiring 31B parallel to the X-axis direction. 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. Additionally, the blackening layer is etched into 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. An example of the configuration of the transparent substrate 11 and wiring arrangement is shown in FIGS. 4A and 4B. Figures 4a and 4b correspond to cross-sectional views taken along line A-A' in Figure 3.

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

Additionally, as shown in FIG. 4B, a pair of transparent substrates 11 are used, and wirings 31A and 31B are arranged on the upper and lower surfaces with one transparent substrate 11 in between, and one wiring 31B may be disposed between the transparent substrates 11. In this case as well, blackening layers 32A and 32B etched to the same shape as the wiring are disposed on the upper surfaces of the wirings 31A and 31B. Meanwhile, as previously explained, an adhesion layer may be formed in addition to the copper layer and blackening layer. Therefore, 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. When forming an adhesive layer, it is preferable that the adhesive layer is also etched into the same shape as the wirings 31A and 31B.

The conductive substrate having the mesh-shaped wiring shown in FIGS. 3 and 4A has 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. 1B. It can be formed with a conductive substrate provided.

Taking the case of formation using the conductive substrate of FIG. 1B as an example, first, the copper layer 12A and the blackening layer 13A on one side 11a of the transparent substrate 11 are formed along the Y-axis of FIG. 1B. A plurality of linear patterns parallel to the direction are etched so that they are arranged at predetermined intervals along the X-axis direction. Meanwhile, the X-axis direction in FIG. 1B refers to a direction parallel to the width direction of each layer. Additionally, the Y-axis direction in FIG. 1B refers to a direction perpendicular to the ground in FIG. 1B.

Then, the copper layer 12B and the blackening layer 13B on the other side 11b of the transparent substrate 11 are formed by forming a plurality of linear patterns parallel to the Etch to arrange accordingly.

Through the above operations, a conductive substrate having mesh-shaped wiring shown in Figs. 3 and 4A can be formed. Meanwhile, both sides of the transparent substrate 11 can be etched simultaneously. That is, etching of the copper layers 12A and 12B and blackening layers 13A and 13B can be performed simultaneously. In addition, the conductive substrate further including an adhesion layer patterned in the same shape as the wirings 31A and 31B between the wirings 31A and 31B and the transparent substrate 11 in FIG. 4A is the conductive substrate shown in FIG. 2B. It can be manufactured by etching in the same way.

The conductive substrate having the mesh-shaped wiring shown in FIG. 3 can also be formed by using two conductive substrates shown in FIG. 1A or FIG. 2A. Taking the case where two conductive substrates shown in FIG. 1A are used as an example, a plurality of copper layers 12 and blackening layers 13 are formed on each of the two conductive substrates shown in FIG. 1A parallel to the X-axis direction. Two linear patterns are etched so that they are arranged along the Y-axis direction at predetermined intervals. Then, by orienting the two conductive substrates so that the linear patterns formed on each conductive substrate by the above etching process intersect each other, a conductive substrate with mesh-shaped wiring can be obtained. When two conductive substrates are glued together, the surface on which they are glued is not particularly limited. For example, the surface A in FIG. 1A on which the copper layer 12, etc. is laminated, and the other side 11b in FIG. 1A on which the copper layer 12, etc. are not laminated, are joined together to form FIG. 4B. It may be possible to have the structure shown.

Additionally, for example, the transparent substrate 11 on which the copper layer 12 or the like is not laminated can be joined to the other side 11b of FIG. 1A so that the cross section has the structure shown in FIG. 4A. .

Meanwhile, in FIGS. 4A and 4B, the conductive substrate further includes an adhesion layer patterned in the same shape as the wirings 31A and 31B between the wirings 31A and 31B and the transparent substrate 11, as shown in FIG. 1A. It can be manufactured by using the conductive substrate shown in Fig. 2A instead of the conductive substrate.

The wiring width, the distance between wirings, etc. in the conductive substrate having mesh-shaped wiring shown in FIGS. 3, 4A, and 4B are not particularly limited and can be selected according to, for example, the amount of current to flow through the wiring.

However, according to the conductive substrate of the present embodiment, it has a blackening layer formed using the blackening plating solution described above, and even when the blackening layer and the copper layer are etched and patterned at the same time, the blackening layer and the copper layer can be patterned into a desired shape. there is. Specifically, for example, a wiring having a wiring width of 10 μm or less can be formed. Therefore, the conductive substrate of this embodiment preferably includes wiring with a wiring width of 10 μm or less. The lower limit of the wiring width is not particularly limited, but can be, for example, 3 μm or more.

3, 4A, and 4B show an example of forming a mesh-shaped wiring (wiring pattern) by combining straight wiring, but this is not limited to this form, and the wiring constituting the wiring pattern may be arbitrary. It can be made in the shape of . For example, to prevent moiré (interference patterns) from occurring between display images, the shapes of the wires that make up the mesh-shaped wiring pattern may be made into various shapes such as jagged, curved lines (zigzag straight lines). there is.

In this way, a conductive substrate having a mesh-shaped wiring composed of two layers of wiring can preferably be used, for example, as a conductive substrate for a projected capacitance touch panel.

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

Additionally, the blackening layer included in the conductive substrate of this embodiment can be used as a conductive substrate in which light reflection on the surface of the copper layer is sufficiently suppressed and reflectance is suppressed. Additionally, for example, when used for purposes such as a touch panel, display visibility can be improved.

Additionally, since the blackening layer can be formed by a wet method using the blackening plating solution described above, a conductive substrate can be produced with better productivity compared to the case of forming the blackening layer using a conventional dry method.

(Conductive substrate manufacturing method)

Next, a configuration example of the conductive substrate manufacturing method of this embodiment will be described.

The method for manufacturing a conductive substrate of this 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. You can.

Meanwhile, as the blackening plating solution, the blackening plating solution described above can be used, specifically, the blackening plating solution containing nickel ions and copper ions and having a pH of 4.0 or more and 5.8 or less.

Below, the method for manufacturing a conductive substrate of this embodiment will be described in detail.

On the other hand, by the conductive substrate manufacturing method of this embodiment, the previously described conductive substrate can be appropriately manufactured as needed. Therefore, except for the points described below, the configuration can be the same as that of the conductive substrate described above, so some descriptions are omitted.

The transparent substrate used in the copper layer formation process can be prepared in advance. The type of transparent substrate used is not particularly limited, but as described above, a transparent substrate such as a resin substrate (resin film) or glass substrate that transmits visible light can be preferably used. The transparent substrate may be cut to an arbitrary size in advance as needed.

And, as previously explained, the copper layer preferably has a copper thin film layer. Additionally, the copper layer may have a copper thin film layer and a copper plating layer. Thus, the copper layer forming process may include, for example, a process of forming a copper thin film layer by a dry plating method. In addition, the copper layer forming process may include a process of forming a copper thin film layer by a dry plating method and a process of forming a copper plating layer by using the copper thin film layer as a power supply layer and an electroplating method, which is a type of wet plating method.

The dry plating method used in the process of forming the copper thin film layer is not particularly limited, and for example, vapor deposition, sputtering, or ion plating can be used. Meanwhile, as a vapor deposition method, a vacuum vapor deposition method can be preferably used. As a dry plating method used in the process of forming a copper thin film layer, it is more preferable to use a sputtering method because it is particularly easy to control the film thickness.

Next, the process for forming the copper plating layer is explained. The conditions in the process of forming a copper plating layer by a wet plating method, that is, the electroplating treatment conditions, are not particularly limited, and the conditions according to a normal method may be adopted. For example, a copper plating layer can be formed by supplying a base material on which a copper thin film layer is formed to a plating tank containing a copper plating solution, and controlling the current density, the transfer speed of the base material, etc.

Next, the blackening layer formation process is explained.

In the blackening layer formation process, the blackening layer can be formed using a blackening plating solution containing the nickel ions and copper ions described above and having a pH of 4.0 or more and 5.8 or less.

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

Since the blackening plating solution was explained previously, the description is omitted.

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

For example, when forming an adhesion layer between a transparent substrate and a copper layer, an adhesion layer forming process of forming an adhesion layer on the surface of the transparent substrate on which the copper layer is formed can be performed. When performing the adhesion layer forming process, the copper layer forming process may be performed after the adhesion layer forming process, and in the copper layer forming process, a copper thin film layer may be formed on the substrate on which the adhesion layer was formed on the transparent substrate in this process. You can.

In the adhesion layer formation process, 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 a dry plating method, for example, sputtering method, ion plating method, vapor deposition method, etc. can be preferably used. When forming an adhesion layer by a dry method, it is more preferable to use a sputtering method because it is easy to control the film thickness. Meanwhile, as described above, one or more elements selected from carbon, oxygen, hydrogen, and nitrogen may be added to the adhesion layer. In this case, a reactive sputtering method may be additionally used.

The conductive substrate obtained by the conductive substrate manufacturing method of this embodiment can be used for various purposes, such as a touch panel, for example. And when using for various purposes, it is preferable that the copper layer and blackening layer contained in the conductive substrate of this embodiment are patterned. On the other hand, when forming an adhesion layer, it is preferable that the adhesion layer is also patterned. The copper layer, blackening layer, and in some cases even the adhesion layer can be patterned to suit the desired wiring pattern, for example, and the copper layer, blackening layer, and even the adhesion layer in some cases are patterned in the same shape. It is desirable.

Thus, the method of manufacturing a conductive substrate of this embodiment may include a patterning process for patterning the copper layer and the blackening layer. In addition, when forming an adhesion layer, the patterning process can be a process of patterning the adhesion layer, copper layer, and blackening layer.

The specific method of the patterning process is not particularly limited and can be performed by any method. For example, in the case of a conductive substrate 10A in which a copper layer 12 and a blackening layer 13 are laminated on a transparent substrate 11 as shown in FIG. 1A, first, on the surface A on the blackening layer 13 A resist placement step may be performed to place a resist having a desired pattern. Next, an etching step of supplying an etchant to the surface A of the blackening layer 13, that is, the surface on which the resist is placed, 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 this embodiment shows almost the same etchant reactivity as the copper layer. Therefore, the etching solution used in the etching step is not particularly limited, and preferably, an etching solution generally used for etching the copper layer can be used.

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

The etching solution can be used at room temperature, but it can also be used at a higher temperature to increase reactivity, so for example, it can be used by heating it to 40℃ or higher and 50℃ or lower.

In addition, as shown in FIG. 1B, about the conductive substrate 10B in which copper layers 12A, 12B and blackening layers 13A, 13B are laminated on one side 11a and the other side 11b of the transparent substrate 11. A patterning process can be performed. In this case, for example, a resist placement step of arranging a resist having a desired pattern on the surface A and surface B on the blackening layers 13A and 13B can be performed. Next, an etching step of supplying an etchant to the surface A and surface B of the blackening layers 13A and 13B, that is, the surface on which the resist is placed, can be performed.

There is no particular limitation on the pattern formed in the etching step, and it can be of any shape. For example, in the case of the conductive substrate 10A shown in FIG. 1A, as described above, the copper layer 12 and the blackening layer 13 include a plurality of straight lines, jagged curved lines (zigzag straight lines), etc. A pattern can be formed to do so.

Additionally, in the case of the conductive substrate 10B shown in FIG. 1B, a pattern can be formed to form mesh-shaped wiring in the copper layers 12A and 12B. In this case, it is preferable to pattern the blackening layer 13A 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, for example, in the patterning process, the copper layer 12 or the like may be patterned on the above-described conductive substrate 10A, and then a lamination process may be performed in which two or more patterned conductive substrates are stacked. When stacking, for example, by stacking the copper layer patterns of each conductive substrate so that they intersect, a laminated conductive substrate with mesh-shaped wiring can be obtained.

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

The conductive substrate obtained by the conductive substrate manufacturing method 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 side of a transparent substrate. Additionally, since the blackening layer is formed 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.

Additionally, the blackening layer included in the conductive substrate obtained by the conductive substrate manufacturing method of this embodiment can sufficiently suppress light reflection on the surface of the copper layer, thereby making it possible to create a conductive substrate with suppressed reflectance. Therefore, for example, when used for purposes such as a touch panel, the visibility of the display can be improved.

Furthermore, since the blackening layer can be formed by a wet method using the blackening plating solution described above, a conductive substrate can be produced with better productivity compared to the case of forming the blackening layer using a conventional dry method.

Example

The following will describe specific examples and comparative examples, but the present invention is not limited to these examples.

(Assessment Methods)

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

(1) Reflectance

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

As will be described later, in each experimental example, a conductive substrate having the structure shown in FIG. 1A was manufactured. Therefore, the reflectance measurement is performed by measuring light with a wavelength of 400 nm to 700 nm at an incident angle of 5° and a light reception angle of 5° with respect to the surface A of the blackening layer 13 of the conductive substrate 10A shown in FIG. 1A. The regular reflectance was measured by irradiating at varying intervals of nm, and the average value was taken as the reflectance (average reflectance) of the conductive substrate.

(2) Etching characteristics

First, in the following experimental example, a dry film resist (Hitachi Kasei, RY3310) was adhered to the surface of the blackening layer of the obtained conductive substrate by a lamination method. Then, ultraviolet light exposure was performed through a photomask, and the resist was dissolved and developed with a 1% sodium carbonate aqueous solution. In this way, samples having patterns with resist widths varying by 0.5 μm in the range of 3.0 μm to 10.0 μm were produced. That is, the resist widths were 3.0㎛, 3.5㎛, 4.0㎛····9.5㎛, 10.0㎛, forming 15 types of linear patterns with different widths of 0.5㎛.

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 and removed with an aqueous sodium hydroxide solution.

The obtained sample was observed under a 200x microscope to determine the minimum wiring width of the metal wiring remaining on the conductive substrate. Meanwhile, the metal wiring here includes a blackening layer patterned in a linear form with a wiring width corresponding to the resist width, and a copper layer, that is, wiring.

The smaller the minimum wiring width of the metal wiring remaining on the conductive substrate after peeling off the resist, the closer the etchant reactivity of the copper layer and blackening layer is to the same, and the minimum wiring width of the remaining metal wiring is 10㎛ or less. In this case, it was evaluated as ○ in Table 2 as passing. And, when a metal wiring with a wiring width of 10 μm was not formed, it was evaluated as “×” in Table 2 as a failure.

(Sample production conditions)

In each of the following experimental examples, conductive substrates were produced under the conditions described below and evaluated by the evaluation method described above.

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, amide sulfuric acid, and ammonia was prepared. Meanwhile, nickel ions and copper ions were supplied to the blackening plating solution by adding nickel sulfate hexahydrate and copper sulfate pentahydrate.

Thus, each component was added and prepared so that the nickel ion concentration in the blackened plating layer was 8.9 g/l, the copper ion concentration was 0.05 g/l, and the amide sulfuric acid concentration was 11 g/l.

Additionally, ammonia water was added to the blackening plating solution to adjust the pH of the blackening plating solution to 4.0.

(2) Conductive substrate

(Copper layer formation process)

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

In the copper layer formation process, a copper thin film layer formation process and a copper plating layer formation process were performed.

First, the copper thin film layer formation process will be described.

In the copper thin film layer forming process, 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 process, the above-described transparent substrate from which moisture was removed by first heating to 60° C. was installed in the chamber of the sputtering device.

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

Power was supplied to the copper target previously set at the cathode of the sputtering device, and a thin copper film layer was formed to a thickness of 0.2 μm on one side of the transparent substrate.

Next, in the copper plating layer forming process, a copper plating layer was formed. The copper plating layer was formed into a film using an electroplating method so that the thickness of the copper plating layer was 0.3 μm.

By performing the above copper thin film layer forming process and copper plating layer forming process, a copper layer with a thickness of 0.5 μm was formed.

The substrate produced in the copper layer formation process, on which a copper layer with a thickness of 0.5 μm was formed on a transparent substrate, was immersed in 20 g/l sulfuric acid for 30 seconds, washed, and then subjected to the following blackening layer formation process.

(Blackening layer formation process)

In the blackening layer formation process, a blackening layer was formed on one side of the copper layer by electrolytic plating using the blackening plating solution of this experimental example described above. Meanwhile, in the blackening layer formation process, 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 seconds to form the blackening layer.

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

The conductive substrate obtained through the above process was evaluated for reflectance and etching characteristics as described above. The results are shown in Tables 2 and 3. Meanwhile, Table 2 shows the evaluation results of the etching characteristics, and Table 3 shows the evaluation results of the reflectance.

[Experimental Example 2~Experimental Example 25]

When preparing the blackening plating solution, the blackening plating solution was prepared in the same manner as in Experimental Example 1, except that the copper ion concentration and pH in the blackening plating solution were changed to the values shown in Table 1 for each experimental example.

Meanwhile, for example, in the case of Experimental Example 2, the copper ion concentration was 0.10 g/l and the pH was 4.0.

Additionally, a conductive substrate was produced and evaluated in the same manner as in Experimental Example 1, except that the blackening plating solution produced in each experimental example was used when forming the blackening layer.

The results are shown in Tables 2 and 3.

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

From the results shown in Table 2, in the metal wiring pattern remaining after forming a blackening layer and etching using the blackening 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, the wiring width It was confirmed that the minimum value of was 10㎛ or less. Thus, it was confirmed that in the conductive substrate having a blackening layer formed using these blackening plating solutions, the blackening layer can be patterned into a desired shape when etched together with the copper layer. Additionally, from the results shown in Table 3, the conductive substrates having blackening layers formed using the blackening plating solutions of Experimental Examples 1 to 12 had an average regular reflectance (reflectance) of light with a wavelength of 400 nm to 700 nm of 60% or less. It was confirmed that it was.

In contrast, in Experimental Example 13 and Experimental Examples 18 to 20, which are comparative examples, it was confirmed that a metal wiring pattern with a wiring width of 10 μm did not remain after etching. Therefore, it was confirmed that when the blackening layer was formed using these blackening plating solutions and etched together with the copper layer, it was difficult to pattern the blackening layer into a desired shape.

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

And, in Experimental Examples 14 to 17, it was confirmed that the minimum value of the wiring width was 10㎛ or less in the metal wiring pattern remaining after etching, but plating stains occurred on the formed blackening layer, making it impossible to use it as a conductive substrate. There wasn't.

In the above, the blackening plating solution and the method for manufacturing a conductive substrate have been described in terms of embodiments and examples, but the present invention is not limited to the above 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 Patent Application No. 2016-016592, filed with the Japan Patent Office on January 29, 2016, and the entire contents of Patent Application No. 2016-016592 are incorporated into this international application.

Claims (4)

Contains nickel ions, copper ions and amide sulfuric acid,
A blackening plating solution with a pH of 4.0 to 5.8 and a copper ion concentration of 0.005 g/l to 0.20 g/l. According to paragraph 1,
Blackening plating solution with a nickel ion concentration of 2.0 g/l or more and 20.0 g/l or less. A copper layer forming process of forming a copper layer on at least one side of a transparent substrate,
A method of manufacturing a conductive substrate comprising 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. delete