WO2018042979A1 - Method for producing conductive film, conductive film, touch panel sensor and touch panel - Google Patents

Abstract

The present invention addresses the problem of easily producing a conductive film which is provided with a thin metal wire that has a narrow line width, while exhibiting excellent adhesion to a substrate. A method for producing a conductive film according to the present invention sequentially comprises, in the following order: a step for forming a first metal film on at least one main surface of a substrate; a step for forming a second metal film, which contains a main component that is different from the main component of the first metal film, on the first metal film; a step for forming a resist film, which is provided with an opening part having a line width of 2.0 μm or less, in a region on the second metal film, where a thin metal wire is to be formed; a step for forming a third metal film; a step for removing the resist film; a step for removing the second metal film with use of a second etching liquid, while using the third metal film as a mask; and a step for removing the first metal film with use of a first etching liquid, while using the third metal film as a mask.

Description

Manufacturing method of conductive film, conductive film, touch panel sensor, and touch panel

The present invention relates to a method for producing a conductive film, a conductive film, a touch panel sensor, and a touch panel.

A conductive film in which a conductive portion made of a fine metal wire is arranged on a substrate is used for various purposes. For example, in recent years, with the increase in the mounting rate of touch panels on mobile phones or portable game devices, the demand for conductive films for capacitive touch panel sensors capable of multipoint detection is rapidly expanding.

When using a display having a touch panel, the user views the display from a distance of several tens of centimeters from the display. At this time, in order to prevent the fine metal wires from being visually recognized by the user, it is required to further narrow the width of the fine metal wires.
In general, a fine metal wire having a narrow line width is inferior in adhesion to the substrate, and in order to improve this, a conductive layer provided with a layer having an effect of further improving the adhesion between the substrate and the fine metal wire is provided. Sex films have been proposed.

As the conductive film as described above, Patent Document 1 discloses a transparent conductive film including a transparent electrode layer composed of a fine metal wire pattern on at least one surface of a transparent film substrate, and the fine metal wire is transparent. A first metal layer and a second metal layer in contact with the first metal layer are provided in this order from the film substrate side, and a base metal layer mainly composed of Ni is provided between the transparent film substrate and the first metal layer. A transparent conductive film in which the base metal layer and the first metal layer are in contact with each other is described. Patent Document 1 also describes a method for producing a transparent conductive film.

International Publication No. 2014/156489

The present inventor has examined the method for producing a transparent conductive film described in Patent Document 1, and when trying to form a fine metal wire having a narrower line width, the formed fine metal wire is easily peeled off from the substrate. Or, it has been clarified that there arises a problem that the metal film that becomes the metal fine wire disappears in the etching performed at the time of forming the metal fine wire.

Then, this invention makes it a subject to provide the manufacturing method of the electroconductive film which can manufacture easily the electroconductive film provided with the metal thin wire | line with the narrow line | wire width and excellent adhesiveness to a board | substrate.
Another object of the present invention is to provide a conductive film, a touch panel sensor, and a touch panel.

As a result of intensive studies to achieve the above-mentioned problems, the present inventor has found that the above-mentioned problems can be achieved by the following configuration.

[1] A method for producing a conductive film, comprising: a substrate; and a conductive portion made of a thin metal wire disposed on at least one main surface of the substrate, wherein the conductive film is formed on at least one main surface of the substrate. A step of forming a first metal film, a step of forming a second metal film containing as a main component a component different from the main component of the first metal film on the first metal film, and on the second metal film A step of forming a resist film having an opening in a region where a fine metal wire is formed, a step of forming a third metal film on the two-metal film in the opening by plating, and a resist film Removing the
The step of removing the second metal film using the second metal etchant using the third metal film as a mask, and the step of using the first etchant different from the second etchant using the third metal film as a mask, And a step of removing one metal film in this order, wherein the line width of the opening is 2.0 μm or less.
[2] The method for producing a conductive film according to [1], wherein the second metal film contains copper or an alloy thereof.
[3] The method for producing a conductive film according to [1] or [2], wherein the first metal film contains chromium or an alloy thereof.
[4] The method for producing a conductive film according to any one of [1] to [3], wherein the third metal film contains copper or an alloy thereof.
[5] The method for producing a conductive film according to any one of [1] to [4], wherein the thickness of the first metal film is less than 20 nm.
[6] The method for producing a conductive film according to any one of [1] to [5], wherein the line width of the opening is 1.5 μm or less.
[7] The method for producing a conductive film according to any one of [1] to [6], wherein an etching rate of the second etching liquid with respect to the second metal film is 300 nm or less per minute.
[8] The method for producing a conductive film according to any one of [1] to [7], wherein an etching rate of the first etching solution with respect to the first metal film is 200 nm or less per minute.
[9] Any of [1] to [8], wherein a ratio of an etching rate of the second etching solution to the first metal film to an etching rate of the second etching solution to the second metal film is 0.0005 or less. The manufacturing method of the electroconductive film of description.
[10] A conductive film comprising a substrate and a conductive portion made of a thin metal wire disposed on at least one main surface of the substrate, wherein the thin metal wire includes a first metal layer, a first metal layer, and a first metal layer. A second metal layer containing a component different from the main component of the metal layer as a main component and a third metal layer are provided in this order from the substrate side, and the line width of the thin metal wire is 2.0 μm or less, The conductive film in which the ratio of the line width of the second metal layer to the line width of the one metal layer is more than 1.0 and less than 1.3.
[11] The conductive film according to [10], wherein the second metal layer contains copper or an alloy thereof.
[12] The conductive film according to [10] or [11], wherein the first metal layer contains chromium or an alloy thereof.
[13] The conductive film according to any one of [10] to [12], wherein the third metal layer contains copper or an alloy thereof.
[14] The conductive film according to any one of [10] to [13], wherein the thickness of the first metal layer is 20 nm or less.
[15] The conductive film according to any one of [10] to [14], wherein the thin metal wire has a line width of 1.5 μm or less.
[16] A touch panel sensor comprising the conductive film according to any one of [10] to [15].
[17] A touch panel containing the touch panel sensor according to [16].

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the electroconductive film which can manufacture simply the electroconductive film provided with the metal thin wire excellent in the adhesiveness to a board | substrate with a narrow line | wire width can be provided.
Moreover, according to this invention, a conductive film, a touch panel sensor, and a touch panel can also be provided.

It is sectional drawing of the board | substrate with a 1st metal film obtained by implementing a 1st metal film formation process. It is sectional drawing of the board | substrate with a 2nd metal film obtained by implementing a 2nd metal film formation process. It is sectional drawing of the board | substrate with a resist film obtained by implementing a resist film formation process. It is sectional drawing of the board | substrate with a 3rd metal film obtained by implementing a 3rd metal film formation process. It is sectional drawing of the laminated body obtained by implementing a resist film removal process. It is sectional drawing of the electroconductive film obtained by implementing a 2nd metal film removal process and a 1st metal film removal process. It is a top view of one embodiment of a conductive film. It is sectional drawing in the AA cross section in FIG. 2A. It is a partial enlarged view of the electroconductive part in an electroconductive film. It is a partially expanded sectional view of a metal fine wire. It is sectional drawing of one Embodiment of the electroconductive film manufactured by the conventional method. It is sectional drawing of other embodiment of the electroconductive film manufactured by the conventional method.

Hereinafter, the present invention will be described in detail.
The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments.
In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
Further, in the present specification, “active light” or “radiation” means, for example, the emission line spectrum of a mercury lamp, and far ultraviolet rays, extreme ultraviolet rays (EUV) represented by excimer lasers, X-rays, and electrons. Means a line. In the present specification, light means actinic rays and radiation. Unless otherwise specified, “exposure” in this specification includes not only exposure by mercury lamp, excimer laser, deep ultraviolet ray, X-ray, EUV, but also drawing by particle beam such as electron beam and ion beam. To do.

As a feature of the method for producing a conductive film of the present invention, when producing a thin metal wire having a narrow line width, a predetermined metal film (first metal film and second metal film) is used by using two kinds of etching solutions. The point which is removed. As will be described later, when a thin metal wire having a narrow line width is formed using the method of removing the base metal layer and the first metal film described in Patent Document 1 with one etching solution, the metal thin wire is etched during the etching. Peeling and / or disappearance of the metal film occurs, and a desired fine metal wire cannot be obtained. Therefore, a desired metal thin wire can be easily manufactured by removing a predetermined metal film stepwise using two kinds of etching solutions.

Hereinafter, first, a method for producing a conductive film according to an embodiment of the present invention will be described, and then a conductive film according to an embodiment of the present invention will be described.

[Method for producing conductive film]
The manufacturing method of an electroconductive film has the following processes in this order.
(1) Step of forming a first metal film on at least one main surface of the substrate (first metal film forming step)
(2) Step of forming a second metal film on the first metal film (second metal film forming step)
(3) Step of forming a resist film having an opening in a region where a fine metal wire is formed on the second metal film (resist film forming step)
(4) Step of forming a third metal film on the second metal film in the opening by plating (third metal film forming step)
(5) Step of removing resist film (resist film removing step)
(6) Step of removing the second metal film using the second metal etchant with the third metal film as a mask (second metal film removing step)
(7) Step of removing the first metal film using the first metal etchant with the third metal film as a mask (first metal film removal step)
Hereafter, the procedure of each said process is explained in full detail.

[First metal film formation process]
The first metal film forming step is a step of forming the first metal film on at least one main surface of the substrate. Specifically, as shown in FIG. 1A, the first metal film 11 is formed on the substrate 101 by performing this step.
As will be described later, the first metal layer 11 is obtained by etching the first metal film 11. The first metal layer functions as a base metal layer (base adhesion layer).

〔substrate〕
If the board | substrate 101 has a main surface and supports an electroconductive part, the kind in particular will not be restrict | limited. As the substrate 101, a flexible substrate is preferable, and a flexible insulating substrate is more preferable. Specifically, a resin substrate is preferable.

The substrate 101 has a visible light (wavelength of 400 to 800 nm) light transmittance of preferably 60% or more, more preferably 80% or more, still more preferably 90% or more, and particularly preferably 95% or more.

Examples of the material constituting the resin substrate include polyethersulfone resin, polyacrylic resin, polyurethane resin, polyester resin (polyethylene terephthalate, polyethylene naphthalate, etc.), polycarbonate resin, polysulfone resin, polyamide. Resin, polyarylate resin, polyolefin resin, cellulose resin, polyvinyl chloride resin, cycloolefin resin and the like. Of these, cycloolefin resins are preferred because they have more excellent optical properties.
The thickness of the substrate 101 is not particularly limited, but is preferably 0.05 to 2 mm, more preferably 0.1 to 1 mm, from the viewpoint of the balance between handleability and thinning.
In addition, the substrate 101 may have a multilayer structure, and for example, may include a functional film as one layer. The substrate itself may be a functional film.

[First metal film]
The metal contained in the first metal film 11 is not particularly limited, and a known metal can be used.
The first metal film 11 may contain, for example, metals such as copper, chromium, lead, nickel, gold, silver, tin, and zinc, and alloys of these metals.
Examples of the main component contained in the first metal film 11 include copper, chromium, lead, nickel, gold, silver, tin, and zinc. The main component means a metal having the largest content (mass) among the metals contained in the first metal film 11.
Especially, it is preferable that the 1st metal film 11 contains chromium or its alloy from the point which the function as a base metal layer of a 1st metal layer is more excellent. Moreover, the main component of the first metal film 11 is preferably chromium in that the function of the first metal layer as the base metal layer is more excellent.

The content of the metal constituting the main component in the first metal film 11 is not particularly limited, but is generally preferably 55% by mass or more, and more preferably 70% by mass or more.

The thickness of the first metal film 11 is not particularly limited, but is generally preferably 50 nm or less, more preferably less than 20 nm, and more preferably 15 nm or less.
Although it does not restrict | limit especially as a lower limit of the thickness of the 1st metal film 11, Generally 3 nm or more is preferable.
When the thickness of the first metal film 11 is less than 20 nm, the fine metal wire provided in the conductive film has better adhesion to the substrate.

The formation method of the first metal film 11 is not particularly limited, and a known formation method can be used. Among these, the sputtering method or the vapor deposition method is preferable because a layer having a denser structure can be easily formed.

[Second metal film forming step]
The second metal film forming step is a step of forming a second metal film containing as a main component a component different from the main component of the first metal film on the first metal film. Specifically, as shown in FIG. 1B, the second metal film 12 is formed on the first metal film 11 by performing this step.
As will be described later, the second metal film 12 functions as a seed layer in the plating method. In addition, the second metal layer is obtained by etching the second metal film 12.

As long as the second metal film 12 contains a component different from the main component of the first metal film 11 as a main component, a known metal can be used. For example, when the 1st metal film 11 contains chromium as a main component, the 2nd metal film 12 contains components (for example, copper) other than chromium as a main component.
The second metal film 12 may contain, for example, metals such as copper, chromium, lead, nickel, gold, silver, tin, and zinc, and alloys of these metals.
Examples of the main component contained in the second metal film 12 include copper, chromium, lead, nickel, gold, silver, tin, and zinc. In addition, the said main component intends the metal with the largest content (mass) among the metals contained in the 2nd metal film 12. FIG.
Especially, it is preferable that the main component of the 2nd metal film 12 is the same as the main component of the 3rd metal film mentioned later by the point which is excellent by affinity with the material which comprises the 3rd metal layer mentioned later.
The second metal film 12 preferably contains copper or an alloy thereof in that the function of the second metal film 12 as a seed layer is more excellent. Moreover, the main component of the second metal film 12 is preferably copper in that the function of the second metal film 12 as a seed layer is more excellent.

The content of the metal constituting the main component in the second metal film 12 is not particularly limited, but is generally preferably 80% by mass or more, and more preferably 90% by mass or more.

The thickness of the second metal film 12 is not particularly limited, but is generally preferably 300 nm or less. Although it does not restrict | limit especially as a lower limit of the thickness of the 2nd metal film 12, Generally 30 nm or more is preferable.

The formation method of the second metal film 12 is not particularly limited, and a known formation method can be used. Among them, a sputtering method or a vapor deposition method is preferable because a layer having a denser structure can be easily formed.

[Resist film formation process]
The resist film forming step is a step of forming a resist film having an opening in a region where a fine metal wire is formed. Specifically, as shown in FIG. 1C, a resist film 20 is formed on the second metal film 12 by performing this step.

The resist film 20 includes an opening 21 in a region where a fine metal wire is formed.
The region of the opening 21 in the resist film 20 can be appropriately adjusted according to the region where the metal fine wire is to be disposed. For example, when forming metal fine wires arranged in a mesh shape, a resist film having a mesh-shaped opening is formed. In addition, normally, an opening part is formed in a thin wire shape according to a metal fine wire.
The line width W of the opening is 2.0 μm or less. The line width W is preferably 1.5 μm or less, and more preferably 1.0 μm or less. By setting the line width W of the opening to 2.0 μm or less, it is possible to obtain a fine metal line with a narrow line width. In particular, when the line width W of the opening is 1.5 μm or less, the line width of the obtained fine metal wire becomes thinner, and when the conductive film is applied to, for example, a touch panel sensor, the metal fine wire is more Hard to see. The lower limit of the line width W of the opening is not particularly limited, but is preferably 0.3 μm or more.
In the present specification, the width of the opening means the size of the thin line portion in a direction orthogonal to the extending direction of the thin line portion of the opening. Through each process described later, a fine metal wire having a line width corresponding to the line width of the opening is formed.

The method for forming the resist film 20 on the second metal film 12 is not particularly limited, and a known resist film forming method can be used. Examples thereof include a method having the following steps.
(A) The process of apply | coating the composition for resist film formation on a 2nd metal film, and forming the composition layer for resist film formation.
(B) The process of exposing the composition for resist film formation through a photomask provided with a pattern-form opening part.
(C) The process of developing the resist film formation composition after exposure, and obtaining a resist film.
In addition, between the said process (a) and (b), between (b) and (c), and / or after (c), the composition layer for resist film formation and / or a resist film are used. You may further have the process of heating.

・ Process (a)
It does not restrict | limit especially as a composition for resist film formation which can be used in the said process (a), A well-known resist film formation composition can be used.
Examples of the resist film forming composition include a positive-type or negative-type radiation-sensitive composition.

The method for coating the resist film forming composition on the second metal film is not particularly limited, and a known coating method can be used.
Examples of the method for applying the composition for forming a resist film include a spin coating method, a spray method, a roller coating method, and an immersion method.

After forming the resist film forming composition layer on the second metal film, the resist film forming composition layer may be heated. By heating, an unnecessary solvent remaining in the resist film-forming composition layer is removed, and the resist film-forming composition layer can be made uniform.
The method for heating the composition layer for forming a resist film is not particularly limited, and examples thereof include a method for heating the substrate.
The heating temperature is not particularly limited, but generally 40 to 160 ° C. is preferable.

The thickness of the resist film-forming composition layer is not particularly limited, but the thickness after drying is generally preferably 0.5 to 2.5 μm.

・ Process (b)
It does not restrict | limit especially as a method of exposing the composition layer for resist film formation, A well-known exposure method can be used.
Examples of the method of exposing the resist film forming composition layer include a method of irradiating the resist film forming composition layer with actinic rays or radiation through a photomask having a patterned opening. It is done. The amount of exposure is not particularly limited, but it is generally preferable to irradiate at 1 to 100 mW / cm ² for 0.1 to 10 seconds.

For example, when the resist film forming composition is a positive type, the line width W of the patterned opening provided in the photomask used in the step (b) is generally preferably 2.0 μm or less, and 1.5 μm or less. Is more preferable, and 1.0 μm or less is still more preferable.

The resist film-forming composition layer after exposure may be heated. The heating temperature is not particularly limited, but generally 40 to 160 ° C. is preferable.

・ Process (c)
A method for developing the composition layer for forming a resist film after exposure is not particularly limited, and a known developing method can be used.
Examples of known development methods include a method using a developer containing an organic solvent or an alkali developer.
Examples of the developing method include a dipping method, a paddle method, a spray method, and a dynamic dispensing method.

Further, the resist film after development may be washed using a rinse solution. The rinse solution is not particularly limited, and a known rinse solution can be used. Examples of the rinse liquid include an organic solvent and water.

[Third metal film formation process]
The third metal film forming step is a step of forming a third metal film on the second metal film in the opening of the resist film by plating. Specifically, as shown in FIG. 1D, by performing this process, the third metal film 13 is formed on the second metal film 12 so as to fill the opening 21 in FIG. 1C.
As will be described later, the third metal film 13 becomes a third metal layer in the thin metal wire after a predetermined treatment.

The third metal film 13 is formed by a plating method.
As a plating method, a known plating method can be used. Specific examples include an electrolytic plating method and an electroless plating method, and the electrolytic plating method is preferable from the viewpoint of productivity.

The metal contained in the third metal film 13 is not particularly limited, and a known metal can be used.
The third metal film 13 may contain, for example, metals such as copper, chromium, lead, nickel, gold, silver, tin, and zinc, and alloys of these metals.
In addition, the main component of the third metal film 13 and the main component of the first metal film 11 are preferably different from each other in that the solubility in the etching solution is different.
Especially, it is preferable that the 3rd metal film 13 contains copper or its alloy by the point which the electroconductivity of a 3rd metal layer is more excellent. Moreover, the main component of the third metal film 13 is preferably copper in that the conductivity of the third metal layer is more excellent.
The main component means a metal having the largest content (mass) among the metals contained in the third metal film 13.

The content of the metal constituting the main component in the third metal film 13 is not particularly limited, but is generally preferably 80% by mass or more, and more preferably 90% by mass or more.

The thickness of the third metal film 13 is not particularly limited, but is generally preferably 3 μm or less, more preferably 2 μm or less, and most preferably 1 μm or less. Although it does not restrict | limit especially as a lower limit of the thickness of the 3rd metal film 13, Generally 0.1 micrometer or more is preferable.

[Resist film removal process]
The resist film removing step is a step of removing the resist film. Specifically, as shown in FIG. 1E, by performing this step, a laminate including the first metal film 11, the second metal film 12, and the third metal film 13 on the substrate 101 is obtained. It is done.

The method for removing the resist film is not particularly limited, and examples thereof include a method for removing the resist film using a known resist film removing solution.
Examples of the resist film removing liquid include an organic solvent and an alkaline solution.
The method for bringing the resist film removing solution into contact with the resist film is not particularly limited, and examples thereof include a dipping method, a paddle method, a spray method, and a dynamic dispensing method.

[Second metal film removal step]
The second metal film removing step is a step of removing the second metal film using the second metal etchant using the third metal film as a mask. By performing this step, the second metal film in the region where the third metal film is not disposed is removed.
1F shows the conductive film 30 obtained after performing the second metal film removal step and the first metal film removal step described later, and the conductive film 30 includes a substrate 101 and a thin metal wire 103. . The thin metal wire 103 includes a first metal layer 201, a second metal layer 202, and a third metal layer 203 in order from the substrate 101 side.

The present inventor, when forming a thin metal wire having a narrow line width, in the step of removing the second metal film, as in the transparent conductive film manufacturing method (semi-additive method) described in paragraph 0087 of Patent Document 1. It has been found that if the first metal film is also removed together, a desired fine metal wire cannot be obtained. The reason is that the second metal film (and the third metal film) is not intended compared to the first metal film due to the difference in solubility in the etchant between the first metal film and the second metal film. It is presumed that this is because a large amount of the first metal film is unintentionally removed compared to the second metal film. When the second metal film (and the third metal film) is unintentionally removed in comparison with the first metal film, as shown in FIG. 5 (cross-sectional view in the line width direction of the thin metal wire), In the thin metal wire 103A disposed on the substrate 101, the line width of the first metal layer 201A is larger than the line width of the second metal layer 202A and the third metal layer 203A. Further, when the first metal film is unintentionally removed more than the second metal film, the first metal film is disposed on the substrate 101 as shown in FIG. 6 (cross-sectional view in the width direction of the fine metal wire). In the thin metal wire 103B, the line width of the first metal layer 201B is smaller than the line widths of the second metal layer 202B and the third metal layer 203B.

If the phenomenon shown in FIG. 5 occurs, the line width of the second metal film (and the third metal film) becomes thin, and the electrical resistivity of the metal thin line becomes large, and / or during etching. In addition, the second metal film (and the third metal film) is likely to fail.
On the other hand, if the phenomenon shown in FIG. 6 occurs, the adhesion between the fine metal wire and the substrate tends to be insufficient. If the adhesion between the fine metal wires and the substrate is insufficient, the fine metal wires are easily peeled from the substrate. When the fine metal wires are peeled off from the substrate, the fine metal wires are likely to be disconnected at that portion.

The manufacturing method of the conductive film which concerns on embodiment of this invention removes the 2nd metal film using a 2nd etching liquid (2nd metal film removal process), and 1st using a 1st etching liquid. A step of removing the metal film (second metal film removal step) is provided in this order.
Here, the first etching solution and the second etching solution mean different etching solutions. The different etching liquids mean etching liquids having different kinds of components, ratios (compositions) of the components to be contained, component contents, and / or temperatures, and the like. It is preferable that the type, the ratio of components to be contained, and / or the content of components are different.

The second metal film removal step removes the “second metal film in the region where the third metal film is not laminated”, in other words, “the second metal film in the region where the resist film is laminated”. Is preferably removed in the first metal film removal step, in other words, “the first metal film in the region where the second metal film is not laminated”, in other words, “the first metal film removed in the second metal film removal step”. The “first metal film in the region where the two metal films have been laminated” is preferable.

Since the manufacturing method of the electroconductive film which concerns on embodiment of this invention has the process of removing a 2nd metal film and a 1st metal film using different etching liquid as above-mentioned, FIG. It is presumed that a problem such as 6 is not likely to occur due to the removal of the first metal film and the second metal film using a single etching solution.

The second etching solution is not particularly limited as long as the second metal film can be dissolved and removed, and a known etching solution can be used.
Known etching solutions include, for example, ferric chloride solution, cupric chloride solution, ammonia alkali solution, sulfuric acid-hydrogen peroxide mixture, phosphoric acid-hydrogen peroxide mixture, and the like.

Although it does not restrict | limit especially as an etching rate with respect to a 2nd metal film of a 2nd etching liquid, The point of a 2nd etching liquid is a point with which the electroconductive film provided with the metal fine wire which was more excellent in the adhesiveness to a board | substrate is obtained more easily. The etching rate for the second metal film is preferably 300 nm / min (hereinafter, “Anm is expressed as“ Anm / min ”per minute”) or less, more preferably 200 nm / min or less.
The lower limit of the etching rate for the second metal film is not particularly limited, but is generally preferably 30 nm / min or more.
The etching rate of the second etching solution with respect to the second metal film can be adjusted by adjusting the concentration and temperature of the second etching solution.
In addition, in this specification, the etching rate of each metal film of each etching liquid means the etching rate measured by the following method.

(Etching rate measurement method)
The measurement of the etching rate with respect to the metal film by the etching liquid in this specification shall be performed by the following method.
First, a model substrate is prepared in which a target metal film is formed with a thickness of 10 μm on a silicon wafer. Next, the thickness of the metal film was measured after the model substrate was immersed in the target etching solution for 5 minutes, and the thickness of the metal film decreased before and after the immersion was calculated, and this was divided by 5 (minutes). To calculate the etching rate.
For measuring the thickness, a surface shape measuring device Dektak 6M (manufactured by Veeco) is used.

The ratio of the etching rate for the first metal film (ER1) of the second etching solution to the “etching rate for the second metal film (ER2)” of the second etching solution (ie, the etching rate for the first metal film) / Etching rate with respect to the second metal film, ER1 / ER2) is not particularly limited, but the second etching solution is difficult to dissolve the first metal film, in other words, the second metal film is selectively dissolved. In this respect, 0.01 or less is preferable, 0.002 or less is more preferable, and less than 0.0005 is even more preferable.
Although it does not restrict | limit especially as a lower limit of ER1 / ER2 of a 2nd etching liquid, Generally 0 or more is preferable.
The case where ER1 / ER2 of the second etching solution is 0 means a case where the second etching solution does not substantially dissolve the first metal film.
When the ER1 / ER2 of the second etching solution is less than 0.0005, a conductive film including a fine metal wire that is more excellent in adhesion to the substrate can be obtained more easily.

The method for etching the second metal film using the second etching solution is not particularly limited, and a known method can be used.

[First metal film removal step]
The first metal film removal step is a step of removing the first metal film using the first etching solution. By performing this step, the first metal film in the region where the third metal film is not disposed is removed.
The first etching solution is not particularly limited as long as the first metal film can be dissolved and removed, and a known etching solution can be used.
Examples of known etching solutions include cerium diammonium nitrate (ammonium cerium nitrate) -perchloric acid-water mixture, ammonium cerium nitrate-nitric acid-water mixture, and the like.

Although it does not restrict | limit especially as an etching rate with respect to a 1st metal film of a 1st etching liquid, The point of a 1st etching liquid is a point by which the electroconductive film provided with the metal fine wire excellent by the adhesiveness to a board | substrate is obtained more simply. The etching rate for the first metal film is preferably 400 nm / min or less, more preferably 200 nm / min or less, and still more preferably 100 nm / min.
The lower limit of the etching rate for the first metal film is not particularly limited, but generally 10 nm / min is preferable.
The etching rate of the first etching solution with respect to the first metal film can be adjusted by adjusting the concentration and temperature of the first etching solution.

The ratio of the etching rate of the first etching solution to the second metal film (ER2) to the etching rate of the first etching solution to the first metal film (ER1) (etching rate of the second metal film / first The etching rate for one metal film, ER2 / ER1) is not particularly limited, but is 0.01 in that the first etching solution hardly dissolves the second metal film (selectively dissolves the first metal film). The following is preferable, and 0.002 or less is more preferable.
Although it does not restrict | limit especially as a lower limit of ER2 / ER1 of a 1st etching liquid, Generally 0 or more are preferable.
The case where ER2 / ER1 of the first etching solution is 0 is intended when the first etching solution does not substantially dissolve the second metal film.

The method for etching the first metal film using the first etching solution is not particularly limited, and a known method can be used.

[Conductive film]
A predetermined conductive film is manufactured by the procedure described above.
The conductive film of the present invention includes a substrate and a conductive portion made of a fine metal wire disposed on at least one main surface of the substrate. In the conductive film, the conductive portion is usually composed of a plurality of fine metal wires. For example, when a conductive film is used for a touch panel sensor, the conductive portion can be used as a transparent electrode and / or a lead wiring.
In the present specification, the main surface means a surface having the largest area facing each other among the surfaces constituting the substrate, and corresponds to a surface facing the thickness direction of the substrate.

FIG. 2A is a top view of one embodiment of the conductive film, and FIG. 2B is a cross-sectional view taken along the line AA. FIG. 3 is a partially enlarged view of a conductive portion in the conductive film.
2A and 2B, the conductive film 100 includes a substrate 101 and a conductive portion 102 disposed on one main surface of the substrate 101.

2A and 2B show the form of the conductive film having a planar shape, the conductive film is not limited to the above. The conductive film may have a three-dimensional shape (three-dimensional shape). Examples of the three-dimensional shape include a three-dimensional shape containing a curved surface, and more specifically, a hemispherical shape, a kamaboko shape, a wavy shape, an uneven shape, and a cylindrical shape.
In FIGS. 2A and 2B, the conductive portion 102 is disposed on one main surface of the substrate 101, but the embodiment is not limited thereto. For example, the conductive portion 102 may be disposed on both main surfaces of the substrate 101.
2A and 2B, the conductive portions 102 are arranged in the form of six stripes, but the present invention is not limited to this configuration, and other arrangements may be used.

FIG. 3 is a partially enlarged top view of the conductive portion 102, and the conductive portion 102 includes a mesh pattern including a plurality of fine metal wires 103 and a plurality of openings 104 formed by intersecting metal fine wires 103. To do.
The line width of the fine metal wire 103 is 2.0 μm or less, more preferably 1.5 μm or less, and still more preferably 1.0 μm or less.
The lower limit of the line width of the fine metal wire 103 is not particularly limited, but generally 0.2 μm or more is preferable.
When the line width of the thin metal wire 103 is 2.0 μm or less, for example, when a conductive film is applied to the touch panel sensor, the user of the touch panel is less likely to visually recognize the thin metal wire.

In the present specification, the line width of the fine metal wire 103 refers to a first metal layer and a second metal layer, which will be described later, in a cross section in the width direction of the fine metal wire 103 (cross section orthogonal to the extending direction of the fine metal wire). And the maximum line width among the line widths of the third metal layer is intended. That is, the line widths of the first metal layer, the second metal layer, and the third metal layer are equal to or smaller than the line width of the metal thin wire 103.
The form of the first to third metal layers and the method for measuring the line width will be described later.

The thickness of the fine metal wire 103 is not particularly limited, but is generally preferably 0.1 to 5.0 μm, and preferably 0.2 to 2.0 μm from the viewpoint of conductivity.
The length X of one side of the opening 104 is preferably 20 to 250 μm.

In FIG. 3, the opening 104 has a substantially rhombus shape. However, other polygonal shapes (for example, a triangle, a quadrangle, a hexagon, and a random polygon) may be used. Further, the shape of one side may be a curved shape or a circular arc shape in addition to a linear shape. In the case of the arc shape, for example, the two opposing sides may have an outwardly convex arc shape, and the other two opposing sides may have an inwardly convex arc shape. The shape of each side may be a wavy shape in which an outwardly convex arc and an inwardly convex arc are continuous. Of course, the shape of each side may be a sine curve.
In FIG. 3, the conductive portion 102 has a mesh pattern, but is not limited to this form.

FIG. 4 is a cross-sectional view of the fine metal wire 103. The thin metal wire 103 includes a first metal layer 201, a second metal layer 202, and a third metal layer 203 in order from the substrate 101 side. The shapes of the first metal layer 201, the second metal layer 202, and the third metal layer 203 are all thin wires corresponding to the shape of the metal thin wires 103.

[First metal layer]
The first metal layer 201 has conductivity, and has an action (adhesion improving action) for holding the second metal layer 202 disposed thereon on the substrate. That is, the first metal layer 201 functions as a base metal layer.
As described above, the first metal layer 201 is formed by performing an etching process on the first metal film.
The kind of metal contained in the first metal layer 201 is the same as the kind of metal contained in the first metal film described above.
Moreover, the suitable range of the thickness of the 1st metal layer 201 is the same as the suitable range of the thickness of the 1st metal film mentioned above. In addition, the thickness of the 1st metal layer in an electroconductive film can also be measured in the case of the measurement of the line | wire width of a 1st metal layer mentioned later.

The line width of the first metal layer 201 is 2.0 μm or less, preferably 1.5 μm or less, and more preferably 1.0 μm or less.
The line width of the first metal layer 201 is obtained by embedding the metal thin wire 103 together with the substrate 101 in a resin and cutting it with an ultramicrotome in the width direction (direction perpendicular to the extending direction of the metal thin wire). It means the line width measured by observing with a scanning electron microscope (S-5500, manufactured by Hitachi High-Technologies Corporation) after depositing carbon on the obtained cross section. The same applies to the line widths of the second metal layer 202 and the third metal layer 203 described later.

The relationship between the first metal layer 201 and the line width of the second metal layer 202 described later is the ratio of the line width of the second metal layer 202 to the line width of the first metal layer 201 (the line of the second metal layer). Width / line width of the first metal layer) is preferably more than 1.0, more preferably 1.01 or more, preferably less than 1.3, and less than 1.25. Is more preferable and 1.2 or less is more preferable.
When the line width of the second metal layer / the line width of the first metal layer is greater than 1.0, the fine metal wire included in the conductive film has better visibility.
On the other hand, when the line width of the second metal layer / the line width of the first metal layer is less than 1.3, the fine metal wire included in the conductive film has better adhesion to the substrate.
[Second metal layer]
The second metal layer 202 has a function of improving the adhesion of the third metal layer 203 and a seed layer when the third metal layer 203 is formed.
As described above, the second metal layer 202 is formed by etching the second metal film.
The kind of metal contained in the second metal layer 202 is the same as the kind of metal contained in the second metal film described above. Among these, the main component of the second metal layer 202 is preferably the same as the main component of the third metal layer 203 described later in that it is more excellent in affinity with the material constituting the third metal layer 203 described later. .
Moreover, the suitable range of the thickness of the 2nd metal layer 202 is the same as the suitable range of the thickness of the 2nd metal film mentioned above. In addition, the thickness of the 2nd metal layer in an electroconductive film can also be measured in the case of the measurement of the line | wire width of a 1st metal layer mentioned above.

The line width of the second metal layer 202 is 2.0 μm or less, preferably 1.5 μm or less, and more preferably 1.0 μm or less.
The line width of the second metal layer 202 preferably satisfies the relationship with the line width of the first metal layer 201 already described.

[Third metal layer]
The third metal layer 203 has conductivity and has an action of ensuring the conduction of the fine metal wires.
The kind of metal contained in the third metal layer 203 is the same as the kind of metal contained in the third metal film described above.
The preferred range of the thickness of the third metal layer 203 is the same as the preferred range of the thickness of the third metal film described above. In addition, the thickness of the 3rd metal layer in an electroconductive film can also be measured in the case of the measurement of the line | wire width of a 1st metal layer mentioned above.

The line width of the third metal layer 203 is 2.0 μm or less, preferably 1.5 μm or less, and more preferably 1.0 μm or less.

The conductive film manufactured by the above manufacturing method can be used for various applications. Applications include, for example, various electrode films, heat generating sheets, and printed wiring boards. Especially, it is preferable to use an electroconductive film for a touch panel sensor, and it is more preferable to use it for a capacitive touch panel sensor. In a touch panel including the conductive film as a touch panel sensor, it is difficult to visually recognize a fine metal wire.
Note that examples of the configuration of the touch panel include a touch panel module described in paragraphs 0020 to 0027 of JP-A-2015-195004, and the above contents are incorporated in this specification.

Hereinafter, the present invention will be described in more detail based on examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the examples shown below.
Unless otherwise specified, parts and% are based on mass.

[Example 1]
On the COP film (cycloolefin polymer film, thickness 80 μm), Cr was formed to a thickness of 10 nm using a sputtering apparatus to obtain a first metal film. Subsequently, Cu was formed to a thickness of 50 nm on the first metal film to obtain a second metal film. Next, a resist film forming composition (“FHi-622BC”, manufactured by Fuji Film Co., Ltd., viscosity 11 mPa · s) is adjusted by adjusting the rotation speed of the spin coater so that the thickness after drying becomes 1 μm. It apply | coated on the metal film and it was made to dry at 100 degreeC for 1 minute, and the composition layer for resist film formation was obtained. The resist film forming composition layer is irradiated with light having a wavelength of 365 nm (exposure amount: 16 mW / cm ² ) using a parallel light exposure machine through a photomask having a linear opening with a line width of 0.8 μm. Irradiation was performed for 2 seconds, and heating was performed at 100 ° C. for 1 minute (post-baking) to obtain a composition layer for forming a resist film after exposure. Next, the resist film-forming composition after exposure was developed with a 0.5 M aqueous sodium hydroxide solution to obtain a patterned resist film. The patterned opening of the resist film had a line width of 1.0 μm ± 0.1 μm.
For the laminate comprising the substrate, the first metal film, the second metal film, and the resist film having a patterned opening in this order, produced by the above procedure, a copper sulfate high-throw bath (Top Lucina as an additive) Electroplating was performed using HT-A and Top Lucina HT-B (both manufactured by Okuno Pharmaceutical Co., Ltd.). As electroplating conditions, the current density was 3 A / dm ² and the conduction time was 20 seconds. A third metal film was formed on the second metal film in the pattern-shaped opening by electroplating. That is, a patterned third metal film was obtained. At this time, the thickness of the third metal film was 300 nm. Next, the resist film was peeled off using 1M sodium hydroxide aqueous solution. Next, the second metal film was prepared using a second etching solution (Cu etching solution, “Cu etchant” manufactured by Wako Pure Chemical Industries, Ltd.) whose concentration was adjusted so that the etching rate for the second metal film was 200 nm / min. Was etched.
Next, the first etching solution (manufactured by Nippon Chemical Industry Co., Ltd .; Cr etching solution; “alkaline chromium etching solution”; the stock solution was used; the etching rate for the first metal film was 100 nm / min) was used. The metal film was etched, and the electroconductive film 1 provided with a board | substrate and a metal fine wire was obtained.

[Example 2]
A conductive film 2 was obtained in the same manner as in Example 1 except that the thickness of the first metal film was 20 nm.

[Example 3]
The concentration of the second etching solution was adjusted so that the etching rate for the second metal film was 500 nm / min, and the concentration of the first etching solution was set so that the etching rate for the first metal film was 100 nm / min. Except having adjusted, the conductive film 3 was obtained by the same operation as Example 1. FIG. Compared to the conductive film 1, the line width and thickness of the fine metal wires were uneven. Moreover, although disconnection was confirmed in part, it was within a practical range.

[Example 4]
The concentration of the second etching solution is adjusted so that the etching rate for the second metal film is 200 nm / min, and the concentration of the first etching solution is 400 nm / min for the etching rate for the first metal film. Except having adjusted so, the electroconductive film 4 was obtained by operation similar to Example 1. FIG. Compared with the conductive film 1, the adhesion was reduced, but was within the practical range.

[Comparative Example 1]
The first metal film was formed using a copper alloy so as to have a thickness of 15 nm, and the second etching liquid (manufactured by Wako Pure Chemical Industries, Ltd.) whose concentration was adjusted so that the etching rate for the second metal film was 200 nm / min. The first metal film and the second metal film were etched using only a Cu etching solution, “Cu etchant”), and the same operation as in Example 1 was performed. In addition, the metal color derived from the second metal film indicates that the second metal film of the part other than the part where the third metal film is laminated (the part covered with the resist film) is completely removed. It went until it could confirm visually that disappeared. As a result, the fine metal wires were peeled in the etching solution.
The main component of the copper alloy was copper, and the copper content was 70% by mass of the entire copper alloy.

[Comparative Example 2]
The first metal film was formed to have a thickness of 15 nm using a copper alloy (similar to that used in Comparative Example 1), and the etching rate for the second metal film was 200 nm / min as the second etching solution. Using ferric chloride (manufactured by Wako Pure Chemical Industries, Ltd.) aqueous solution with adjusted concentration, and etching the first metal film and the second metal film using only the second etching solution. Except for this, the same operation as in Example 1 was performed. In addition, until the second metal film of the portion other than the portion where the third metal film is laminated is completely removed, it can be visually confirmed that the metal color derived from the second metal film has disappeared. went. As a result, the metal color derived from the third metal film in the thin metal wire also disappeared.

[Comparative Example 3]
The same operation as in Comparative Example 1 was performed except that the first metal film was formed to have a thickness of 35 nm using a copper alloy (similar to that used in Comparative Example 1). As a result, the fine metal wires were peeled in the etching solution.

[Comparative Example 4]
The same operation as in Comparative Example 2 was performed except that the first metal film was formed to have a thickness of 35 nm using a copper alloy (similar to that used in Comparative Example 1). As a result, the metal color derived from the third metal film in the thin metal wire also disappeared.

[Comparative Example 5]
The same operation as in Comparative Example 1 was performed except that the first metal film was not formed. As a result, the third metal film after etching maintained the shape of the third metal film before etching. However, in the tape peeling test carried out by the method described later, the fine metal wires were largely peeled off.

[Comparative Example 6]
The first metal film is formed using Cr so as to have a thickness of 10 nm, and the second metal film is used only with a second etching solution whose concentration is adjusted to an etching rate of 200 nm / min. The same operation as in Example 1 was performed except that the second metal film was etched.
In addition, the 2nd etching liquid used what mixed ammonium cerium (IV) nitrate and nitric acid, and diluted with the pure water. In Table 1, it described as "ammonium cerium nitrate liquid." All reagents are manufactured by Tokyo Chemical Industry Co., Ltd.
In addition, the metal color derived from the second metal film indicates that the second metal film of the part other than the part where the third metal film is laminated (the part covered with the resist film) is completely removed. It went until it could confirm visually that disappeared. As a result, the metal color derived from the third metal film in the thin metal wire also disappeared.

In addition, the etching rate with respect to the 1st metal film of the 1st etching liquid used in the above was measured with the following method. Other etching rates were also measured by the same method as described below. The measurement results are also shown in Table 1.
First, a model substrate in which a first metal film was formed with a thickness of 10 μm on a silicon wafer was prepared. Next, the thickness of the first metal film after the model substrate was immersed in the first etching solution for 5 minutes was measured, and the thickness of the first metal film decreased before and after the immersion was calculated. Then, the etching rate was calculated.
In addition, the surface shape measuring apparatus Dektak6M (made by Veeco) was used for the measurement of thickness.

[Evaluation]
[Formability of fine metal wires]
The shape of the fine metal wire was confirmed visually. The results were evaluated according to the following criteria, and the evaluation results are shown in Table 1. Practically “B” or more is preferable.
A: There was no unevenness in the line width and thickness of the fine metal wires, and no disconnection was confirmed.
B: Unevenness occurred in the line width and thickness of the fine metal wires. Moreover, although disconnection was also confirmed in part, it was in a practical range as a conductive film.
C: The fine metal wire was peeled off and / or the fine metal wire disappeared.

[Adhesion to substrate]
The adhesion of the fine metal wire to the substrate was evaluated by a tape peeling test.
After each cellulosic film produced by the above method was used, the cellophane tape film (“CT24” manufactured by Nichiban Co., Ltd.) was pressed and adhered to the base material main surface on the side provided with the fine metal wires, The cellophane tape was peeled off. Thereafter, the peeled area (%) of the fine metal wire on the substrate (area of the peeled fine metal wire / area of the fine metal wire in the test piece × 100) was visually confirmed.
The results were evaluated according to the following criteria, and the evaluation results are shown in Table 1. Practically “B” or more is preferable.
A: Peeling of the fine metal wire was not observed.
B: Peeling of the fine metal wire was observed, but the peeled area was less than 1%.
C: Peeling of fine metal wires was observed, and the peeled area was 1% or more.
D: The tape peeling test could not be performed because the fine metal wires had already peeled and / or the fine metal wires had disappeared.

[Line width of fine metal wires]
The line width of the metal fine wire with which the electroconductive film produced by said method is equipped, and the line width of each metal layer were measured with the following method. The results are summarized in Table 1.
First, the conductive film is embedded in a resin together with the substrate, cut in the width direction (direction perpendicular to the extending direction of the fine metal wires) using an ultramicrotome, and carbon is deposited on the obtained cross section This was observed using a scanning electron microscope (S-5500, manufactured by Hitachi High-Technologies Corporation). The respective line widths of the first metal layer, the second metal layer, and the third metal layer were measured, and the maximum line width was listed in Table 1 as the line width (μm) of the thin metal wire.

Table 1 shows the conditions in the metal film forming steps according to the examples and comparative examples, the type and etching rate of the etching solution used, the line width of the obtained conductive film, and the evaluation (Part 1). It was described in each line over (No. 4). For example, in Example 1, the first metal film is made of Cr and has a thickness of 10 nm, the second metal film is made of Cu and has a thickness of 50 nm, and the third metal film is made of Cu and has a thickness of 300 nm. . The type of the second etching solution is a Cu etching solution, the etching rate (ER2) of the second etching solution to the second metal film is 200 nm / min, and the etching rate (ER1) of the second etching solution to the first metal film. Is less than 0.1 nm / min, and as a result, the ER1 / ER2 of the second etchant is less than 0.0005. The first etching solution is a Cr etching solution, the etching rate (ER1) of the first etching solution to the first metal film is 100 nm / min, and the etching rate (ER2) of the first etching solution to the second metal film is As a result, the ER2 / ER1 of the first etching solution is less than 0.01. And the line width of the thin metal wire in the obtained conductive film is 1 μm, the line width of the first metal layer is 0.9 μm, the line width of the second metal layer is 1 μm, and the line width of the third metal layer is 1 μm. As a result, the line width of the second metal layer / the line width of the first metal layer was 1.11. In the evaluation, the formability of the fine metal wire was “A”, and the adhesion of the fine metal wire to the substrate was “A”. Other examples and comparative examples were also described in the same manner as described above.

In the above table, “None” means that the first metal film was not formed, and “−” means that the first metal film was not formed, and therefore there was no corresponding thickness.

In the above table, “None” represents that the first etching solution was not used, and “−” represents that there was no corresponding measurement result or calculation result. Further, “<” represents that the measured value or the calculated value is less than the numerical value.

In the above table, the methods for producing conductive films of Comparative Examples 1 to 4 did not provide the desired conductive film, and the line width could not be measured. did. “-” Indicates that there is no corresponding measurement result or calculation result.

From the results shown in Table 1, according to the method for producing conductive films of Examples 1 to 4, a conductive film including a thin metal wire having a narrow line width and excellent adhesion to a substrate can be easily produced. I found out that On the other hand, the methods for producing conductive films of Comparative Examples 1 to 6 could not produce a desired conductive film.
The method for producing a conductive film of Example 1 in which the thickness of the first metal layer is less than 20 nm includes a fine metal wire that is superior in adhesion to the substrate as compared with the method for producing a conductive film of Example 2. It turned out that an electroconductive film can be manufactured simply.
The manufacturing method of the conductive film of Example 1 whose etching rate with respect to the 2nd metal film of a 2nd etching liquid is 300 nm or less per minute was more excellent compared with the manufacturing method of the conductive film of Example 3. It turned out that the electroconductive film which has the metal fine wire which has a shape can be manufactured.
The manufacturing method of the conductive film of Example 1 whose etching rate with respect to the 1st metal film of a 1st etching liquid is 200 nm or less per minute is compared with the manufacturing method of the conductive film of Example 4, to a board | substrate. It turned out that an electroconductive film provided with the metal fine wire excellent in adhesiveness can be manufactured simply.
The ratio of the etching rate of the second etching solution to the first metal film with respect to the etching rate of the second etching solution to the second metal film is 0.0005 or less. Compared with the manufacturing method of 4 electroconductive films, it turned out that the electroconductive film provided with the metal fine wire excellent in the adhesiveness to a board | substrate can be manufactured simply.

DESCRIPTION OF SYMBOLS 11 1st metal film 12 2nd metal film 13 3rd metal film 20 Resist film 21 Opening part 30,100 Conductive film 101 Substrate 102 Conductive part 103 Metal fine wire 104 Opening part 201 First metal layer 202 Second metal layer 203 1st Three metal layers

Claims (17)

1. A substrate,
   A conductive part that is disposed on at least one main surface of the substrate and is composed of a thin metal wire;
   Forming a first metal film on at least one main surface of the substrate;
   Forming a second metal film containing as a main component a component different from the main component of the first metal film on the first metal film;
   Forming a resist film having an opening in a region where the thin metal wire is formed on the second metal film;
   Forming a third metal film on the second metal film in the opening by plating;
   Removing the resist film;
   Using the second metal film as a mask and removing the second metal film using a second etching solution;
   Using the first metal film as a mask and removing the first metal film using a first etchant different from the second etchant;
   In this order,
   The manufacturing method of the electroconductive film whose line width of the said opening part is 2.0 micrometers or less.
2. The method for producing a conductive film according to claim 1, wherein the second metal film contains copper or an alloy thereof.
3. The method for producing a conductive film according to claim 1 or 2, wherein the first metal film contains chromium or an alloy thereof.
4. The method for producing a conductive film according to any one of claims 1 to 3, wherein the third metal film contains copper or an alloy thereof.
5. The method for producing a conductive film according to any one of claims 1 to 4, wherein the thickness of the first metal film is less than 20 nm.
6. The method for producing a conductive film according to any one of claims 1 to 5, wherein a line width of the opening is 1.5 µm or less.
7. The method for producing a conductive film according to any one of claims 1 to 6, wherein an etching rate of the second etching liquid with respect to the second metal film is 300 nm or less per minute.
8. The method for producing a conductive film according to any one of claims 1 to 7, wherein an etching rate of the first etching liquid with respect to the first metal film is 200 nm or less per minute.
9. The ratio of the etching rate of the second etching solution to the first metal film to the etching rate of the second etching solution to the second metal film is 0.0005 or less. The manufacturing method of the electroconductive film as described in a term.
10. A substrate,
    A conductive film that is disposed on at least one main surface of the substrate and is composed of a thin metal wire;
    The thin metal wire is
    A first metal layer;
    A second metal layer containing as a main component a component different from the main component of the first metal layer,
    A third metal layer, and in this order from the substrate side,
    The metal thin wire has a line width of 2.0 μm or less,
    The conductive film in which the ratio of the line width of the second metal layer to the line width of the first metal layer is more than 1.0 and less than 1.3.
11. The conductive film according to claim 10, wherein the second metal layer contains copper or an alloy thereof.
12. The conductive film according to claim 10 or 11, wherein the first metal layer contains chromium or an alloy thereof.
13. The conductive film according to any one of claims 10 to 12, wherein the third metal layer contains copper or an alloy thereof.
14. The conductive film according to any one of claims 10 to 13, wherein the thickness of the first metal layer is 20 nm or less.
15. The conductive film according to any one of claims 10 to 14, wherein a line width of the thin metal wire is 1.5 µm or less.
16. A touch panel sensor comprising the conductive film according to any one of claims 10 to 15.
17. A touch panel comprising the touch panel sensor according to claim 16.
    

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