TW202108369A - Transparent conductive film and patterning method thereof - Google Patents

Abstract

An object of the present invention is to provide a transparent conductive film and a patterning method thereof, which have excellent stability of a copper layer and are capable of easily being patterned and suppressing damage to a metal layer in a transparent conductive layer. To achieve the object of the present invention, a conductive film (1) includes: a transparent base material (2); a transparent conductive layer (3) which is disposed on the transparent base material (2) and has a first inorganic oxide layer (6), a metal layer (7) and a second inorganic oxide layer (8) in order; a copper layer (4) arranged on the upper side of the transparent conductive layer (3); and a copper oxide layer (5) arranged on the upper side of the copper layer (4).

Description

Conductive film and patterning method thereof

The present invention relates to a conductive film and a patterning method thereof, and more specifically, to a conductive film and a patterning method thereof that can be used for optical purposes.

It has been known that a transparent conductive film provided with a transparent conductive layer is used in optical applications such as a touch panel.

For example, a transparent conductive film is described that includes a transparent substrate and a light-transmitting inorganic layer, and the light-transmitting inorganic layer sequentially includes a first inorganic oxide layer, a metal layer, and a second inorganic oxide layer (such as , Refer to Patent Document 1).

Regarding the transparent conductive film of Patent Document 1, it is known that since a metal layer such as a silver layer functions as a conductive layer, it exhibits superior conductivity (low resistance) than a conventional transparent conductive layer containing indium oxide oxide.

On the other hand, for the transparent conductive film, in order to form a draw-around wiring on the outer edge of the touch input area to achieve narrow margins, a copper layer-attached conductive layer formed by layering a copper layer on the surface of the transparent conductive layer is proposed.性膜。 The film. Since the copper layer is easily oxidized and the conductivity of such a conductive film with a copper layer changes over time, abnormalities such as uneven conductivity such as surface resistance (sheet resistance) in a plan view over a long period of time occur. Therefore, it is known to arrange a metal layer such as a copper-nickel alloy on the copper layer to suppress the natural oxidation of the copper layer (for example, refer to Patent Document 2).

In the conductive film with a copper layer of Patent Document 2, the copper layer and the transparent conductive film are patterned separately in order to form the draw-wound wiring from the copper layer to the edge, and the conductive film is formed from the transparent conductive film to the touch The electrode pattern of the panel. Prior art literature Patent literature

[Patent Document 1] Japanese Patent Laid-Open No. 2016-155377 [Patent Document 2] Japanese Patent Laid-Open No. 2013-1009

[The problem to be solved by the invention]

In addition, in order to meet the various demands in recent years, research is under way to achieve narrow margins and stability of the margin (copper layer) of the low resistance transparent conductive film represented by Patent Document 1 on the upper surface of the transparent conductive layer. Furthermore, a copper layer and a copper-nickel layer are arranged.

In this case, since it is necessary to pattern the copper-nickel layer and the copper layer together, it is necessary to use a strong acid-based etching solution. As a result, an abnormality occurs in which the etching solution reaches the metal layer (silver layer) of the transparent conductive layer and damages the metal layer. As a result, sometimes the metal layer cannot be formed into the required electrode pattern, or the required surface resistance cannot be achieved.

The present invention provides a conductive film that has excellent stability of a copper layer, can easily pattern the copper layer, and can suppress damage to the metal layer in the transparent conductive layer, and a patterning method thereof. [Technical means to solve the problem]

The present invention [1] includes a conductive film including: a transparent substrate; and is disposed on one side of the transparent substrate in the thickness direction, and is provided with a first inorganic oxide layer, a metal layer, and a second inorganic oxide layer in this order The transparent conductive layer; the copper layer arranged on one side of the thickness direction of the above-mentioned transparent conductive layer; and the copper oxide layer arranged on one side of the thickness direction of the above-mentioned copper layer.

The present invention [2] includes the conductive film as described in [1], wherein the thickness of the copper oxide layer is 13 nm or less.

The present invention [3] includes the conductive film as described in [1] or [2], wherein the copper layer and the copper oxide layer are patterned.

The present invention [4] includes a method for patterning a conductive film, comprising: preparing the conductive film as described in [1] or [2]; and by combining a neutral etchant with the conductive film The step of patterning the copper oxide layer and the copper layer while contacting one side in the thickness direction. [Effects of Invention]

According to the conductive film of the present invention, since it has a transparent conductive layer having a first inorganic oxide layer, a metal layer, and a second inorganic oxide layer in this order, it has excellent conductivity.

According to the conductive film of the present invention, since the copper oxide layer is arranged on one side of the thickness direction of the copper layer, the natural oxidation of the copper layer is suppressed and the stability of the copper layer is excellent.

According to the conductive film of the present invention, since the copper oxide layer is provided, the copper oxide layer and the copper layer can be easily etched with a neutral etching solution. In addition, since the inorganic oxide layer arranged on the other side of the thickness direction of the copper layer is not easily etched by the neutral etching solution, damage to the metal layer in the transparent conductive layer can be suppressed.

According to the patterning method of the present invention, since the copper oxide layer and the copper layer are patterned by contacting the neutral etchant with the conductive film, it is possible to suppress the transparent conduction on the other side of the copper oxide layer in the thickness direction. Layer of etching. Therefore, damage to the metal layer in the transparent conductive layer can be suppressed.

1, the conductive film 1 as one embodiment of the present invention will be described.

In Figure 1, the vertical direction on the paper is the vertical direction (thickness direction, the first direction), the upper side of the paper is the upper side (one side in the thickness direction, the first direction), and the lower side of the paper is the lower side (the other side in the thickness direction, the first direction). 1 direction on the other side). In addition, the left-right direction and the depth direction on the paper surface are plane directions orthogonal to the up-down direction. Specifically, according to the direction arrows in each figure.

1. Conductive film The conductive film 1 is formed into a film shape (including a sheet shape) with a specific thickness, extends in a plane direction orthogonal to the thickness direction, and has a flat upper surface (one surface in the thickness direction) and a flat lower surface (the other surface in the thickness direction) . The conductive film 1 is, for example, a part such as a substrate for a touch panel included in an optical device (for example, an image display device), and is not an optical device. That is, the conductive film 1 is used to make parts for optical devices, etc., and does not include image display elements such as LCD (Liquid Crystal Display) modules, or LEDs (Light Emitting Diodes), etc. The light source is a device that circulates separately and can be used in industry.

Specifically, as shown in FIG. 1, the conductive film 1 of the first embodiment is a conductive film including a transparent base material 2, a transparent conductive layer 3, a copper layer 4, and a copper oxide layer 5 in this order. That is, the conductive film 1 includes: a transparent substrate 2, a transparent conductive layer 3 disposed on the upper side of the transparent substrate 2, a copper layer 4 disposed on the upper side of the transparent conductive layer 3, and an oxide disposed on the upper side of the copper layer 4. Copper layer 5. Preferably, the conductive film 1 is composed of only the transparent substrate 2, the transparent conductive layer 3, the copper layer 4, and the copper oxide layer 5. Hereinafter, each layer will be described in detail.

2. Transparent substrate The transparent substrate is a support material that ensures the mechanical strength of the conductive film 1. That is, the transparent substrate 2 supports the transparent conductive layer 3, the copper layer 4, and the copper oxide layer 5.

The transparent substrate 2 has a film shape, and is the lowermost layer of the conductive film 1.

The transparent substrate 2 is, for example, a polymer film having transparency. As the material of the polymer film, for example, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; for example, polymethacrylate, etc. (former Base) acrylic resin (acrylic resin and/or methacrylic resin); for example, polyethylene, polypropylene, cycloolefin polymers (for example, norenes, cyclopentadienes, cyclohexadienes and other polymers) Olefin resins such as polycarbonate resins, polyether ether resins, polyarylate resins, melamine resins, polyamide resins, polyimide resins, cellulose resins, polystyrene resins, etc. The polymer film can be used singly or in combination of two or more kinds.

From the viewpoints of transparency, heat resistance, mechanical strength, etc., a polyester resin is preferable, and polyethylene terephthalate is more preferable.

The total light transmittance (JIS K 7375-2008) of the transparent substrate 2 is, for example, 80% or more, preferably 85% or more.

From the viewpoints of mechanical strength, transparency, and click characteristics when the conductive film 1 is made into a touch panel film, the thickness of the transparent substrate 2 is, for example, 2 μm or more, preferably 20 μm or more, and, for example, It is 300 μm or less, preferably 150 μm or less.

The thickness of the transparent base material 2 can be measured using a film thickness meter (digital dial gauge), for example.

Furthermore, an easy-to-bond layer, an adhesive layer, a spacer, etc. can also be arranged on the upper surface and/or the lower surface of the transparent substrate 2 as needed.

3. Transparent conductive layer The transparent conductive layer 3 is formed into a desired pattern (patterned transparent conductive layer 3A described below) in the second patterning step described below, for example, a conductive layer that becomes the electrode pattern in the touch input area of the touch panel .

The transparent conductive layer 3 has a film shape, and is arranged on the entire upper surface of the transparent substrate 2 in a manner of contact with the upper surface of the transparent substrate 2. More specifically, the transparent conductive layer 3 is arranged between the transparent substrate 2 and the copper layer 4 in a manner of contacting the upper surface of the transparent substrate 2 and the lower surface of the copper layer 4.

The transparent conductive layer 3 includes a first inorganic oxide layer 6, a metal layer 7, and a second inorganic oxide layer 8 in this order. That is, the transparent conductive layer 3 includes a first inorganic oxide layer 6 arranged on the upper surface of the transparent substrate 2, a metal layer 7 arranged on the upper surface of the first inorganic oxide layer 6, and a metal layer 7 arranged on the metal layer 7. The second inorganic oxide layer 8 on the upper surface. Preferably, the transparent conductive layer 3 is composed of only the first inorganic oxide layer 6, the metal layer 7, and the second inorganic oxide layer 8.

The surface resistance of the upper surface of the transparent conductive layer 3 is, for example, 10 Ω/□ or less, preferably 5 Ω/□ or less, and, for example, 0.1 Ω/□ or more.

The total light transmittance (JIS K 7375-2008) of the transparent conductive layer 3 is, for example, 60% or more, preferably 85% or more.

The average reflectance of the near-infrared rays (wavelength 850-2500 nm) of the transparent conductive layer 3 is, for example, 10% or more, preferably 50% or more, and, for example, 95% or less.

The total thickness of the transparent conductive layer 3 (ie, the total thickness of the first inorganic oxide layer 6, the metal layer 7, and the second inorganic oxide layer 8) is, for example, 20 nm or more, preferably 40 nm or more, and, for example, 150 nm or less, preferably 100 nm or less. The total thickness of the transparent conductive layer 3 and the thickness of each layer can be measured by, for example, a transmission electron microscope (TEM, Transmission Electron Microscopy) by cross-sectional observation. Hereinafter, the first inorganic oxide layer 6, the metal layer 7, and the second inorganic oxide layer 8 will be described in detail.

4. The first inorganic oxide layer The first inorganic oxide layer 6 suppresses the penetration of hydrogen or carbon from the transparent substrate 2 into the barrier layer of the metal layer 7. In addition, the first inorganic oxide layer 6 is also an optical adjustment layer that suppresses the visible light reflectance of the metal layer 7 together with the second inorganic oxide layer 8 and improves the visible light transmittance (transparency) of the transparent conductive layer 3. In addition, the first inorganic oxide layer 6 is preferably a conductive layer that imparts conductivity to the transparent conductive layer 3 together with the metal layer 7, and more preferably a transparent conductive layer.

The first inorganic oxide layer 6 has a film shape and is the lowest layer in the transparent conductive layer 3. More specifically, the first inorganic oxide layer 6 is arranged on the entire upper surface of the transparent substrate 2 so as to be in contact with the upper surface of the transparent substrate 2.

Examples of inorganic oxides forming the first inorganic oxide layer 6 include those selected from In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, W, Metal oxides formed by at least one metal in the group consisting of Fe, Pb, Ni, Nb, and Cr. The metal oxide can be further doped with metal atoms shown in the above group as needed.

As the inorganic oxide, from the viewpoint of reducing the surface resistance and ensuring excellent transparency, preferably, an oxide containing indium oxide (an oxide containing indium oxide) can be cited.

The indium oxide-containing oxide may contain only indium (In) as a metal element, or may contain (semi) metal elements other than indium (In). The oxide containing indium oxide is preferably indium (In) as the main metal element. The oxide containing indium oxide whose main metal element is indium has an excellent barrier function, and it is easy to better inhibit the corrosion of the metal layer 7 caused by the influence of water and the like.

Specific examples of oxides containing indium oxide include indium zinc composite oxide (IZO), indium gallium composite oxide (IGO), indium gallium zinc composite oxide (IGZO), and indium tin composite oxide ( ITO), more preferably, indium tin composite oxide (ITO) is mentioned. The "ITO" in this specification should just be a composite oxide containing at least indium (In) and tin (Sn), and may contain additional components other than these. As additional components, for example, metal elements other than In and Sn, such as metal elements shown in the above group, and combinations thereof, can be cited. The content of the additional component is, for example, 5 mass% or less.

The content of tin oxide (SnO ₂ ) contained in ITO relative to the total amount of tin oxide and indium oxide (In ₂ O ₃ ) is, for example, 0.5% by mass or more, preferably 3% by mass or more, more preferably 10% by mass % Or more, and, for example, 35% by mass or less, preferably 20% by mass or less, and more preferably 15% by mass or less. The content of indium oxide (In ₂ O ₃ ) is the remainder of the content of tin oxide (SnO _{2 ).} If the content of tin oxide (SnO ₂ ) contained in ITO is in the above range, the crystallinity of the ITO film can be easily adjusted.

The first inorganic oxide layer 6 may be either crystalline or amorphous.

The thickness of the first inorganic oxide layer 6 is, for example, 5 nm or more, preferably 20 nm or more, and, for example, 100 nm or less, preferably 50 nm or less. If the thickness of the first inorganic oxide layer 6 is in the above range, the visible light transmittance of the transparent conductive layer 3 can be easily adjusted to a higher level.

5. Metal layer The metal layer 7 is a conductive layer that imparts conductivity to the transparent conductive layer 3 together with the first inorganic oxide layer 6 and the second inorganic oxide layer 8. In addition, the metal layer 7 is also a low-resistance layer that reduces the surface resistance of the transparent conductive layer 3. In addition, it is preferable that the metal layer 7 is also an infrared reflective layer that imparts high infrared reflectance.

The metal layer 7 has a film shape and is arranged on the upper surface of the first inorganic oxide layer 6 so as to be in contact with the upper surface of the first inorganic oxide layer 6. More specifically, the metal layer 7 is arranged on the first inorganic oxide layer 6 and the second inorganic oxide so as to be in contact with the upper surface of the first inorganic oxide layer 6 and the lower surface of the second inorganic oxide layer 8. Between layer 8.

The metal forming the metal layer 7 is not limited as long as it is a metal with a low surface resistance. For example, it may include: including Ti, Si, Nb, In, Zn, Sn, Au, Ag, Cu, Al, Co, Cr, One metal from the group consisting of Ni, Pb, Pd, Pt, Ge, Ru, Nd, Mg, Ca, Na, W, Zr, Ta, and Hf, or an alloy containing two or more of these metals.

As the metal, preferably, silver (Ag) and silver alloys are cited. If the metal is silver or silver alloy, the resistance value of the transparent conductive layer 3 can be lowered. In addition, the transparent conductive layer 3 with a particularly high average reflectivity in the near infrared region (wavelength 850 ~ 2500 nm) can be obtained. It is well used for image display devices used outdoors.

The silver alloy contains silver as a main component and other metals as a subsidiary component. The metal elements of the secondary components are not limited. Examples of silver alloys include Ag-Cu alloys, Ag-Pd alloys, Ag-Pd-Cu alloys, Ag-Pd-Cu-Ge alloys, Ag-Cu-Au alloys, Ag-Cu-In alloys, and Ag-Cu alloys. Cu-Sn alloy, Ag-Ru-Cu alloy, Ag-Ru-Au alloy, Ag-Nd alloy, Ag-Mg alloy, Ag-Ca alloy, Ag-Na alloy, Ag-Ni alloy, Ag-Ti alloy, Ag -In alloy, Ag-Sn alloy, etc. From the viewpoint of wet heat durability, the silver alloy preferably includes Ag-Cu alloy, Ag-Cu-In alloy, Ag-Cu-Sn alloy, Ag-Pd alloy, Ag-Pd-Cu alloy, and the like.

The content of silver in the silver alloy is, for example, 80% by mass or more, preferably 90% by mass or more, more preferably 95% by mass or more, and, for example, 99.9% by mass or less. The content ratio of other metals in the silver alloy is the remainder of the above-mentioned silver content ratio.

From the viewpoint of increasing the transmittance of the transparent conductive layer 3, the thickness of the metal layer 7 is, for example, 1 nm or more, preferably 5 nm or more, and, for example, 20 nm or less, preferably 10 nm or less.

6. The second inorganic oxide layer The second inorganic oxide layer 8 is a barrier layer that prevents external oxygen or moisture from penetrating into the metal layer 7. In addition, the second inorganic oxide layer 8 is also an optical adjustment layer that suppresses the visible light reflectivity of the metal layer 7 together with the first inorganic oxide layer 6 and increases the visible light transmittance of the transparent conductive layer 3. Furthermore, it is preferable that the second inorganic oxide layer 8 is a conductive layer that imparts conductivity to the transparent conductive layer 3 together with the metal layer 7, and more preferably a transparent conductive layer.

The second inorganic oxide layer 8 has a film shape and is the uppermost layer in the transparent conductive layer 3. More specifically, the second inorganic oxide layer 8 is arranged on the entire upper surface of the metal layer 7 so as to be in contact with the upper surface of the metal layer 7.

Examples of the inorganic oxide forming the second inorganic oxide layer 8 include the inorganic oxides exemplified in the first inorganic oxide layer 6, preferably an oxide containing indium oxide, and more preferably ITO.

The inorganic oxide forming the second inorganic oxide layer 8 and the inorganic oxide forming the first inorganic oxide layer 6 may be the same or different. From the viewpoint of patterning characteristics, it is preferably the same as the first inorganic oxide layer. 6 The same inorganic oxide.

When the second inorganic oxide layer 8 contains ITO, the content of tin oxide (SnO ₂ ) contained in the ITO is the same as that of the first inorganic oxide layer 6.

The second inorganic oxide layer 8 may be either crystalline or amorphous.

The thickness of the second inorganic oxide layer 8 is, for example, 5 nm or more, preferably 20 nm or more, and, for example, 100 nm or less, preferably 50 nm or less. If the thickness of the second inorganic oxide layer 8 is in the above range, the visible light transmittance of the transparent conductive layer 3 can be easily adjusted to a higher level.

The ratio of the thickness of the second inorganic oxide layer 8 to the thickness of the first inorganic oxide layer 6 (the second inorganic oxide layer 8/the first inorganic oxide layer 6) is, for example, 0.5 or more, preferably 0.75 or more, Moreover, it is 1.5 or less, for example, Preferably it is 1.25 or less. If the above-mentioned ratio is within the above-mentioned range, the deterioration of the metal layer 7 can be further suppressed.

The ratio of the thickness of the second inorganic oxide layer 8 to the thickness of the metal layer 7 (second inorganic oxide layer 8/metal layer 7) is, for example, 2.0 or more, preferably 3.0 or more, and, for example, 10 or less. Preferably, it is 8.0 or less.

7. Copper layer The copper layer 4 is formed into a desired pattern (patterned copper layer 4A described below) in the first patterning step described below, for example, it becomes the outer edge portion (outer periphery) of the touch input area. ) Is the conductive layer of the wiring pattern (for example, drawn wiring).

The copper layer 4 has a film shape, and is arranged on the entire upper surface of the transparent conductive layer 3 in a manner of being in contact with the upper surface of the transparent conductive layer 3. More specifically, the copper layer 4 is disposed between the transparent conductive layer 3 and the copper oxide layer 5 in a manner of contacting the upper surface of the transparent conductive layer 3 and the lower surface of the copper oxide layer 5.

Examples of the material of the copper layer 4 include copper or copper alloys. The metal constituting the copper alloy is not limited, and examples thereof include silver, tin, chromium, and zirconium. From the viewpoint of conductivity and the like, preferably, copper is used.

The thickness of the copper layer 4 is, for example, 100 nm or more, preferably 150 nm or more, and, for example, 400 nm or less, preferably 300 nm or less. If the thickness of the metal layer 7 is more than the above-mentioned lower limit, the conductivity of the copper layer 4 is excellent. Therefore, it is possible to cope with the increase in the size of the touch panel, and to form a narrower and longer wiring pattern (stretched copper wiring at the edge). If the thickness of the copper layer 4 is less than or equal to the above upper limit, the edge portion can be thinned.

The thickness of the copper layer 4 can be measured by cross-sectional observation using, for example, a transmission electron microscope (TEM).

8. Copper oxide layer The copper oxide layer 5 is a protective layer that suppresses the decrease in conductivity caused by the natural oxidation of the copper layer 4. In addition, the copper oxide layer 5 is formed into a desired pattern (patterned copper oxide layer 5A described below) together with the copper layer 4, for example, becomes the outer edge of the touch input area (outer periphery) of the touch panel ( The layer of the wiring pattern (for example, the drawn wiring) in the outer peripheral edge portion).

The copper oxide layer 5 has a film shape and is the uppermost layer of the conductive film 1. More specifically, the copper oxide layer 5 is arranged on the entire upper surface of the copper layer 4 so as to be in contact with the upper surface of the copper layer 4.

The material of the copper oxide layer 5 is an oxide of copper or copper alloy. The metal constituting the copper alloy is not limited, and examples thereof include silver, tin, chromium, and zirconium. From the viewpoint of conductivity and the like, preferably, copper oxide is used.

The thickness of the copper oxide layer 5 is, for example, 1 nm or more, preferably 3 nm or more, for example, 30 nm or less, preferably 13 nm or less, more preferably 8 nm or less, and still more preferably 6 nm or less. If the thickness of the copper oxide layer 5 is within the above range, on the upper surface of the conductive film 1 (the copper oxide layer 5 and the copper layer 4), the temporal change (natural oxidation) of its surface resistance can be further suppressed, and It can further reduce the uneven surface resistance.

The ratio of the thickness of the copper oxide layer 5 to the thickness of the copper layer 4 (copper oxide layer 5/copper layer 4) is, for example, 1/100 or more, preferably 2/100 or more, and, for example, 15/100 or less. It is preferably 7/100 or less, more preferably 5/100 or less, and still more preferably 3/100 or less. If the above ratio is within the range, the unevenness of the surface resistance can be further reduced.

The thickness of the copper oxide layer 5 can be measured using, for example, a scanning fluorescent X-ray analyzer.

9. Manufacturing method of conductive film Next, a method of manufacturing the conductive film 1 will be described. The manufacturing method of the conductive film 1 includes, for example, a step of sequentially arranging (laminating) the transparent conductive layer 3, the copper layer 4, and the copper oxide layer 5 on the transparent substrate 2.

In this method, first, a transparent substrate 2 is prepared. As the transparent substrate 2, a publicly known or commercially available one can be used.

Then, the transparent conductive layer 3 is arranged on the upper surface of the transparent substrate 2. For example, by a dry method, the first inorganic oxide layer 6, the metal layer 7, and the second inorganic oxide layer 8 are sequentially arranged on the upper surface of the transparent substrate 2.

As a dry method, a vacuum vapor deposition method, a sputtering method, an ion plating method, etc. are mentioned, for example. Preferably, a sputtering method is mentioned.

Examples of the gas used in the sputtering method include inert gases such as Ar. In addition, a reactive gas such as oxygen can be used in combination as necessary. When a reactive gas is used in combination, the volume ratio of the reactive gas flow rate to the inert gas flow rate (reactive gas/inert gas) is, for example, 0.1/100 or more, preferably 1/100 or more, and, for example, 5/ Below 100.

Specifically, in the formation of the first inorganic oxide layer 6, as the gas, it is preferable to use an inert gas and a reactive gas in combination. In the formation of the metal layer 7, as the gas, it is preferable to use an inert gas alone. In the formation of the second inorganic oxide layer 8, as the gas, an inert gas and a reactive gas are preferably used in combination.

In the case of using the sputtering method, as the target material, the above-mentioned inorganic oxide or metal constituting each layer can be cited.

The power supply used in the sputtering method can, for example, be used alone or in combination with DC (Direct Current) power supply, MF (Medium Frequency, intermediate frequency)/AC (Alternating Current, alternating current) power supply and RF (Radio Frequency, radio frequency) power supply Preferably, a DC power supply can be cited.

Thereby, the first inorganic oxide layer 6, the metal layer 7, and the second inorganic oxide layer 8 are sequentially formed on the upper surface of the transparent substrate 2.

If necessary, heating may be applied in order to crystallize the first inorganic oxide layer 6 and/or the second inorganic oxide layer 8.

The heating temperature is, for example, 80°C or more and 180°C or less, and the heating time is, for example, 10 minutes or more and 5 hours or less. Heating can be carried out in any environment of atmospheric atmosphere, inert atmosphere, and vacuum.

Then, a copper layer 4 is arranged on the upper surface of the transparent conductive layer 3. For example, the copper layer 4 is formed on the upper surface of the transparent conductive layer 3 by a dry method.

As the dry method, the same method as that described in the above-mentioned formation of the transparent conductive layer 3 can be cited, and preferably, the sputtering method can be cited. By this method, the copper layer 4 having a uniform thickness even if it is a thick film can be formed.

The conditions of the sputtering method in the copper layer 4 may be the same as those exemplified in the formation of the transparent conductive layer 3. It is preferable to use an inert gas alone as a gas in the formation of the copper layer 4. Moreover, as a target material, oxygen-free copper is preferable.

Then, a copper oxide layer 5 is arranged on the upper surface of the copper layer 4. For example, the copper oxide layer 5 is formed on the upper surface of the copper layer 4 by a dry method.

As the dry method, the same method as that described in the above-mentioned formation of the transparent conductive layer 3 can be cited, and preferably, the sputtering method can be cited. By this method, the copper oxide layer 5 with uniform thickness can be formed on the upper surface of the copper layer 4 with better adhesion.

The conditions of the sputtering method in the copper oxide layer 5 can also be the same as the conditions exemplified in the formation of the transparent conductive layer 3. It is preferable to use an inert gas alone or to use an inert gas and a reactive gas (specifically, oxygen) in the formation of the copper oxide layer 5. Moreover, as a target material, copper oxide (CuO) is mentioned preferably.

Thus, as shown in FIG. 1, the conductive film 1 provided with the transparent base material 2, the transparent conductive layer 3, the copper layer 4, and the copper oxide layer 5 can be obtained. The conductive film 1 is a transparent conductive film with a copper layer.

Furthermore, the above-mentioned manufacturing method can be implemented using a roll-to-roll method. In addition, part or all of them may be implemented in batches.

10. Patterning method of conductive film Next, a method of patterning the conductive film 1 will be described. The patterning method of the conductive film 1 includes, for example, a first etching step and a second etching step in this order.

In the first etching step, the copper oxide layer 5 and the copper layer 4 are etched. That is, the neutral etchant is brought into contact with the upper surface (one surface in the thickness direction) of the conductive film 1, that is, the upper surface of the copper oxide layer 5.

For example, by etching the copper oxide layer 5 and the copper layer 4 at the center of the copper oxide layer 5 and the copper layer 4 by etching the required pattern (drawing wiring) at the bottom peripheral end (equivalent to the area of the drawing wiring) in the plan view (touch Input area) is removed.

Specifically, first, as shown in FIG. 2A, the photosensitive dry film photoresist 10 is disposed on the entire upper surface of the copper oxide layer 5, and the dry film photoresist 10 is developed into a desired pattern.

Then, the neutral etching solution is brought into contact with the copper oxide layer 5 exposed from the dry film photoresist 10. Thereby, as shown in FIG. 2B, the copper oxide layer 5 and the copper layer 4 disposed on the lower side thereof are etched by the neutral etching solution. That is, the copper oxide layer 5 and the copper layer 4 are simultaneously etched. On the other side, the transparent conductive layer 3 exposed from the copper layer 4 is not etched.

The pH value of the neutral etching solution is, for example, 5.0 or more, preferably 6.0 or more, and for example, 9.0 or less, preferably 8.0 or less.

As the neutral etching solution, for example, a ferric chloride aqueous solution, a copper chloride aqueous solution, an amine compound-organic acid-copper compound aqueous solution, a copper(II) sulfate aqueous solution, a sulfuric acid-hydrogen peroxide aqueous aqueous solution, etc., are preferred. An amine compound-organic acid-copper compound aqueous solution can be mentioned.

Thereafter, the dry film photoresist 10 is removed from the upper surface of the copper oxide layer 5 by, for example, peeling.

Thereby, as shown in FIG. 2C, the copper oxide layer 5 and the copper layer 4 are patterned. That is, the patterned copper oxide layer 5A and the patterned copper layer 4A are formed. The patterned copper oxide layer 5A and the patterned copper layer 4A have patterns that are substantially the same as each other in a plan view.

In the second etching step, the transparent conductive layer 3 is etched. That is, the acid etching solution is brought into contact with the upper surface of the transparent conductive layer 3.

For example, by forming the required pattern (electrode pattern) in the central part (touch input area) in the plan view, the central part of the transparent conductive layer 3 exposed from the copper layer 4 and the copper oxide layer 5 is removed by etching. .

Specifically, first, as shown in FIG. 2D, a photosensitive dry film photoresist 10 is placed on the entire surface of the patterned copper oxide layer 5A and the upper surface of the transparent conductive layer 3 exposed therefrom, and the dry film photoresist 10 Develop into the desired pattern.

Then, the acid etching solution is brought into contact with the transparent conductive layer 3 exposed from the dry film photoresist 10. Thereby, as shown in FIG. 2E, the transparent conductive layer 3 is etched by the acid etching solution.

The pH value of the acid etching solution is, for example, less than 4.0, preferably less than 3.0.

Examples of acidic etching solutions include aqueous solutions containing acids such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, oxalic acid, phosphoric acid, and mixed acids thereof.

Thereafter, the dry film photoresist 10 is removed from the upper surface of the transparent conductive layer 3, for example, by peeling.

Thereby, the transparent conductive layer 3 is patterned to form a patterned transparent conductive layer 3A (a laminated body composed of a patterned first inorganic oxide layer 6A, a patterned metal layer 7A, and a patterned second inorganic oxide layer 8A ).

Thus, as shown in FIG. 2F, as an embodiment of the conductive film 1, a pattern including a transparent substrate 2, a patterned transparent conductive layer 3A, a patterned copper layer 4A, and a patterned copper oxide layer 5A in this order can be obtained.化conductive film 1A.

The total thickness of the conductive film 1 is, for example, 2 μm or more, preferably 20 μm or more, and, for example, 300 μm or less, preferably 200 μm or less.

The surface resistance of the upper surface of the conductive film 1 (specifically, the copper oxide layer 5 and the copper layer 4 on the lower side) is, for example, 1.0 Ω/□ or less, preferably 0.5 Ω/□ or less, and, for example, 0.001 Above Ω/□.

11. Purpose The conductive film 1 is used, for example, for a base material for a touch panel included in an image display device. As the form of the touch panel, for example, various methods such as an electrostatic capacitance method and a resistive film method can be cited, and in particular, it can be suitably used for a touch panel of an electrostatic capacitance method. Specifically, for example, the patterned conductive film 1A is used as a touch panel by arranging the patterned conductive film 1A on a protective substrate such as a protective glass.

In addition, the conductive film 1 can be used, for example, as a substrate for near-infrared reflection, and can be particularly preferably used in an image quality display device suitable for outdoor use. Specifically, for example, a polarizing film with a transparent conductive layer in which a polarizing element is attached to the conductive film 1 may be arranged in an image display device.

Furthermore, the conductive film 1 can also be suitably used for, for example, an electrophoresis method, a twisted ball method, a thermal rewritable method, an optical writing liquid crystal method, a polymer dispersed liquid crystal method, a guest-host liquid crystal method, a color enhancer display method, and a color changing method. Flexible display elements such as method, electric field precipitation method, etc.

According to this conductive film 1, since the copper oxide layer 5 is provided on the upper side of the copper layer 4, the natural oxidation of the copper layer 4 can be suppressed, and the upper surface of the conductive film 1 (copper layer 4 and copper oxide layer 4) can be suppressed. The uneven surface resistance changes over time. Therefore, the stability of the surface resistance of the upper surface (draw wiring, etc.) of the conductive film 1 is excellent.

In addition, since the protective layer arranged on the upper surface of the copper layer 4 is the copper oxide layer 5, the layers (the copper oxide layer 5 and the copper layer 4) can be easily etched with a neutral etching solution. In addition, since the second inorganic oxide layer 8 disposed under the copper layer 4 is not easily etched by the neutral etching solution, the corrosion of the metal layer 7 in the transparent conductive layer 3 and even the damage of the metal layer 7 can be suppressed.

Moreover, in the patterning method of the conductive film 1, since the copper oxide layer 5 and the copper layer 4 are patterned by contacting the neutral etchant with the conductive film 1, the underside of the copper oxide layer 5 can be suppressed The etching of the transparent conductive layer 3. Therefore, the corrosion of the metal layer 7 in the transparent conductive layer 3 and even the damage of the metal layer 7 can be suppressed.

In addition, since the transparent conductive layer 3 includes the first inorganic oxide layer 6, the metal layer 7, and the second inorganic oxide layer 8, the metal layer 7 functions as a conductive layer and has excellent conductivity. In addition, since the transparent conductive layer 3 has such a three-layer structure, it has excellent transparency, and when the transparent conductive layer 3 is patterned, the visual recognition of the pattern can be suppressed.

Moreover, in the conductive film 1, if the metal layer 7 is a silver layer or a silver alloy layer, the electrical resistance can be lowered, and the reflectivity in the near-infrared region is high, which can effectively block heat rays such as sunlight . Therefore, it can also be better used in an image display device used in an environment where the panel temperature is likely to rise (for example, outdoors, etc.).

Moreover, in the conductive film 1, if the first inorganic oxide layer 6 and the second inorganic oxide layer 8 both contain an indium tin composite oxide, the transparency is excellent, and the visibility of the pattern can be effectively suppressed.

12. Variations In the above embodiment, as shown in FIG. 1, a transparent substrate 2, a transparent conductive layer 3, a copper layer 4, and a copper oxide layer 5 are provided, but for example, a hard coat layer may be further provided between the transparent substrate 2 and the transparent conductive layer 3. Functional layers such as layer, optical adjustment layer, and adhesion layer.

In the above embodiment, as shown in FIG. 1, only the transparent conductive layer 3, the copper layer 4, and the copper oxide layer 5 are provided on the upper surface of the transparent substrate 2. However, for example, the lower surface of the transparent substrate 2 may be sequentially The transparent conductive layer 3, the copper layer 4, and the copper oxide layer 5 are provided, but not shown. [Example]

Examples and comparative examples are shown below to further specifically describe the present invention. Furthermore, the present invention is not limited in any way by the examples and comparative examples. In addition, specific numerical values such as the blending ratio (content ratio), physical property values, and parameters used in the following descriptions can be replaced with the blending ratios (content ratio), physical property values, etc. corresponding to them described in the above-mentioned "embodiment". The upper limit (defined as the value of "below" or "not reached") or the lower limit (defined as the value of "above" or "exceeding") corresponding to the parameters, etc.

Example 1 Prepare a polyethylene terephthalate (PET, Polyethylene Terephthalate) film with a thickness of 50 μm as a transparent substrate.

Then, the PET film was introduced into the vacuum sputtering device, and by the sputtering method, an indium tin oxide layer with a thickness of 40 nm, a silver layer with a thickness of 8 nm, and an indium tin oxide layer with a thickness of 36 nm were sequentially formed from the bottom , Thereby forming a transparent conductive layer.

Furthermore, in the formation of the indium tin oxide layer, a sintered target containing 12% by mass of tin oxide and 88% by mass of indium oxide was used, and a target containing an Ag alloy was used in the formation of the silver layer.

Then, the PET film laminated with the transparent conductive layer was introduced into a vacuum sputtering device, and a copper layer with a thickness of 200 nm was formed by the sputtering method.

Specifically, in a vacuum environment with an argon gas pressure of 0.4 Pa, a Cu target containing oxygen-free copper is used to sputter the transparent conductive layer.

Then, the PET film laminated with a copper layer and a transparent conductive layer was introduced into a vacuum sputtering device, and a copper oxide layer with a thickness of 4 nm was formed by the sputtering method.

Specifically, a CuO target was used to sputter the transparent conductive layer in a vacuum environment with an argon gas pressure of 0.4 Pa.

Thereby, a conductive film provided with a PET film, a transparent conductive layer, a copper layer, and a copper oxide layer is obtained.

Examples 2～4 Except having changed the thickness of the copper oxide layer to the thickness described in Table 1, it carried out similarly to Example 1, and obtained the conductive film.

Comparative example 1 A conductive film 1 was obtained in the same manner as in Example 1 except that the copper oxide layer was not formed.

Comparative example 2 Except that a copper-nickel-titanium alloy layer (CuNiTi layer) with a thickness of 15 nm was formed instead of the copper oxide layer, a conductive film was obtained in the same manner as in Example 1.

(1) Thickness The thickness of the substrate was measured using a film thickness meter (manufactured by Peacock, digital dial gauge DG-205). The thicknesses of the first inorganic oxide layer, the metal layer, the second inorganic oxide layer, and the copper layer are measured by using a transmission electron microscope (manufactured by Hitachi, "HF-2000") on the side profile of the conductive film Observed and measured. The thickness of the copper oxide layer is measured using a scanning fluorescent X-ray analyzer (manufactured by Rigaku Corporation, "ZSX Primus II").

(2) The stability of surface resistance The conductive film of each example and each comparative example was left for 240 hours under the conditions of 60° C. and 95 RH%. After that, the surface resistance of each conductive film was measured at 30 locations at 10 mm intervals in the width direction. The measurement of surface resistance is carried out in accordance with the four-probe method of JIS K7194 (1994).

At this time, the case where the unevenness of the surface resistance (maximum or minimum) is within 5% of the average value of the measured surface resistance is evaluated as 5, and the case where it is within 15% is evaluated as 4, and it is evaluated as 30 Cases within% are evaluated as 3, cases within 50% are evaluated as 2, and cases exceeding 50% are evaluated as 1 (bad). The results are shown in Table 1.

(3)Using the patterning characteristics of neutral etching solution On the upper surface of the conductive film of each example and each comparative example, a masking tape was attached to form stripes with 10 mm intervals, and a neutral etching solution (manufactured by MEC Corporation, "MECBRITE SF-5404B", pH value 7.0, amine compound-organic acid-copper compound aqueous solution), the upper surface is etched.

The more transparent conductive layer of the conductive film is the upper layer (the copper layer and the copper oxide layer in each embodiment, the copper layer in the comparative example 1 and the copper layer and the copper-nickel-titanium layer in the comparative example 2) The case where the alloy layer) was formed in a striped pattern was evaluated as ○, and the case where it was not formed in a striped pattern was evaluated as ×. The results are shown in Table 1.

(4) Using the patterning characteristics of the acid etching solution The same procedure as in (3) above was used, and the etching was performed using acid etching (30 wt% HNO ₃ aqueous solution, pH value below 1.0) instead of neutral etching. After that, using an energy dispersive X-ray analyzer (EDX, manufactured by JEOL Ltd., "JED-2300"), the surface of the transparent conductive layer exposed from the copper layer and the copper oxide layer was observed by element mapping. As a result, in all the conductive films, parts where no silver element was present were seen everywhere, and it was found that the silver layer was damaged. In addition, the surface resistance of the surface of the transparent conductive layer was measured using a four-terminal resistance measuring device. As a result, it was found that the surface resistance of all conductive films increased by more than 15%, and the conductivity decreased.

[Table 1] [Table 1] Thickness of copper oxide layer (nm) Thickness of CuNiTi layer (nm) Stability of surface resistance Utilize the patterning characteristics of neutral etchant Example 1 4 - 5 ○ Example 2 8 - 4 ○ Example 3 12 - 3 ○ Example 4 15 - 2 ○ Comparative example 1 - - 1 ○ Comparative example 2 - 15 5 X

1: Conductive film 1A: Patterned conductive film 2: Transparent substrate 3: Transparent conductive layer 3A: Patterned transparent conductive layer 4: Copper layer 4A: Patterned copper layer 5: Copper oxide layer 5A: Patterned copper oxide 6: The first inorganic oxide layer 6A: Patterned first inorganic oxide layer 7: Metal layer 7A: Patterned metal layer 8: The second inorganic oxide layer 8A: Patterned second inorganic oxide layer 10: Dry film photoresist

Fig. 1 shows a cross-sectional view of an embodiment of the conductive film of the present invention. Figures 2A-F show the steps of the patterning method of the conductive film shown in Figure 1, Figure 2A shows the steps of disposing a dry film photoresist, Figure 2B shows the steps of etching the copper oxide layer and the copper layer, and Figure 2C shows Fig. 2D shows the step of disposing the dry film photoresist, Fig. 2E shows the step of etching the transparent conductive layer, and Fig. 2F shows the step of obtaining a patterned conductive film.

1: Conductive film

2: Transparent substrate

3: Transparent conductive layer

4: Copper layer

5: Copper oxide layer

6: The first inorganic oxide layer

7: Metal layer

8: The second inorganic oxide layer

Claims (4)

A conductive film, which is characterized by having: Transparent substrate A transparent conductive layer arranged on one side of the thickness direction of the above-mentioned transparent substrate, and sequentially provided with a first inorganic oxide layer, a metal layer, and a second inorganic oxide layer; The copper layer arranged on one side of the thickness direction of the above-mentioned transparent conductive layer; and A copper oxide layer arranged on one side of the above-mentioned copper layer in the thickness direction. The conductive film of claim 1, wherein the thickness of the copper oxide layer is 13 nm or less. The conductive film of claim 1 or 2, wherein the copper layer and the copper oxide layer are patterned. A method for patterning a conductive film, which is characterized by having: Steps to prepare the conductive film as in claim 1 or 2; and The step of patterning the copper oxide layer and the copper layer by bringing a neutral etching solution into contact with one surface in the thickness direction of the conductive film.

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