JPWO2014098158A1 - Film forming method, conductive film, and insulating film - Google Patents

Abstract

It is to provide a film with a high resolution pattern. A step of providing a conductive carbon layer; a step of providing an overcoat layer on the conductive carbon layer; a step of disposing a mask on the overcoat layer; and the mask on the overcoat layer. And a step of irradiating the conductive carbon layer with ultraviolet rays from above the mask in an intimately attached and oxygen-containing atmosphere.

Description

  The present invention relates to a transparent conductive film, for example.

  A transparent conductive film substrate in which a transparent conductive film (for example, a transparent conductive film made of indium tin oxide (ITO) or the like) is provided on a transparent substrate is known. This type of substrate is used for a display panel, for example. For example, it is used for a liquid crystal display. Used for plasma displays. Used for organic EL displays. Or it is used for a touch panel. Or it is used for a solar cell. In addition, it is used in various fields.

  The transparent conductive film is formed in a desired pattern. As this pattern forming method, a chemical etching means (a photolithography means using a photoresist or an etchant) is generally employed.

  The chemical etching method is a photoresist film forming process (applying a photoresist paint on the ITO film formed on the entire surface of the substrate) → photoresist film patterning process (exposure development forms the photoresist film into a predetermined pattern) ) → ITO film etching process (etching the ITO film using a predetermined pattern of photoresist film as a mask) → Photoresist film removing process is required. Therefore, the chemical etching method is cumbersome. The chemical etching method has a problem of a decrease in etching accuracy due to swelling of the photoresist film in the solution. The chemical etching method has problems in handling of the etching solution and waste solution treatment.

  As a method for solving the above problem, a laser ablation method has been proposed. In this method, unnecessary portions are removed by directly irradiating a conductive film with a laser. This method does not require a photoresist and enables highly accurate patterning.

  However, in the laser ablation method, applicable substrates are limited. The laser ablation method has a high process cost. In the laser ablation method, the processing speed is slow. Therefore, the laser ablation method is not a method suitable for a mass production process.

  Chemical etching techniques that do not require a photolithography process include “use of iron (III) chloride or iron (III) chloride hexahydrate as an etching component in a composition for etching an oxide surface”, “iron chloride” (III) or iron (III) chloride hexahydrate, in display technology (TFT), in photovoltaics, semiconductor technology, high performance electronics, mineralogy or glass industry, in OLED lighting, in the manufacture of OLED displays, and Use as an etching component in a composition in paste form for the manufacture of photodiodes and for the construction of ITO glass for flat panel screen applications (plasma displays) "" Composition for etching oxide layers " A) Chlorination as an etching component (III) or iron (III) chloride hexahydrate, b) solvent, c) optionally homogeneously dissolved organic thickener, d) optionally at least one inorganic and / or organic acid And optionally e) said composition comprising an additive such as an antifoaming agent, a thixotropic agent, a flow control agent, a degassing agent, an adhesion promoter, and is in paste form and printable. Table 2008-547232).

  “An etching medium for etching a transparent conductive layer of an oxide, comprising phosphoric acid or a salt thereof or a phosphoric acid adduct or a mixture of phosphoric acid and a phosphate and / or a phosphoric acid adduct “Etching medium containing at least one etchant” “A method for etching a transparent conductive layer of oxide, characterized in that the etching medium is applied to a substrate to be etched by a printing process” It has been proposed (Japanese Patent Publication No. 2009-503825).

  However, the techniques disclosed in JP-T-2008-547232 and JP-T-2009-503825 do not easily perform etching in the plane. For this reason, unevenness occurs.

  Incidentally, as the transparent conductive film, in addition to the transparent conductive film made of ITO, a transparent conductive film made of carbon nanotube is known. The carbon nanotube is a tube-shaped material having a diameter of 1 μm or less. An ideal carbon nanotube has a structure in which a carbon hexagonal mesh surface is parallel to the tube axis to form a tube. The tubes may be multiplexed. Carbon nanotubes exhibit metallic or semiconducting properties depending on how the hexagonal network made of carbon is connected and the thickness of the tube. For this reason, carbon nanotubes are expected as functional materials. However, depending on the configuration and manufacturing method of the carbon nanotube, the thickness and direction are random. For this reason, in use, there are cases where it is necessary to recover after the synthesis and purify it, and to treat it according to the form to be used. The following methods have been proposed as a method for patterning carbon nanotubes of this type (Japanese Patent Publication No. 2006-513557, Japanese Patent Publication No. 2007-529884 (Pamphlet of International Publication No. 2005/086982)). For example, a carbon nanotube dispersion is applied to the substrate surface. Thereby, a carbon nanotube film is formed. A binder solution is applied to the carbon nanotube film in a predetermined pattern. After application, the solvent is removed by drying. Thereby, the binder remains in the carbon nanotube film, and the network of carbon nanotubes is strengthened. Thereafter, the substrate is washed with a solvent that does not dissolve the binder. As a result, a pattern is formed in which only the portion where the binder exists (to which the binder has been applied) remains. A photoresist material can also be used instead of the binder. That is, a photoresist-containing paint is applied to the carbon nanotube film. Thereby, the photoresist is impregnated in the network of carbon nanotubes. Thereafter, a predetermined pattern is formed using photolithography. However, the method of patterning after forming the carbon nanotube film on the entire surface of the substrate is complicated.

  There is also a method in which a pre-patterned carbon nanotube film is directly applied and formed on a substrate by an application method such as screen printing, ink jet, or gravure printing. When the patterned carbon nanotube film is formed by a coating method such as screen printing, it is necessary that the physical properties of the carbon nanotube-containing coating are adjusted to the physical properties suitable for the coating method. The carbon nanotube dispersion generally contains a dispersant such as a surfactant. The carbon nanotube dispersion has a relatively low viscosity. In order to obtain ink physical properties suitable for the coating method, it is necessary to add a material for adjusting the viscosity and surface tension to the carbon nanotube dispersion. In this case, the dispersibility of the carbon nanotubes may be deteriorated.

  The following technique is proposed (international publication 2010/113744 pamphlet) as an alternative to the technique proposed in JP-T-2006-513557 and JP-T-2007-529884. That is, an acid having a boiling point of 80 ° C. or higher (for example, sulfuric acid or a sulfonic acid compound), a base having a boiling point of 80 ° C. or higher, or a compound, solvent, resin (for example, primary to fourth that generates an acid or a base by external energy) Cationic resins containing any of the primary amino groups as part of the structure) and conductive film removing agents containing leveling agents have been proposed. The conductive film removing agent is applied to at least a part of the base material with a conductive film having a conductive film containing a whisker-like conductor, a fibrous conductor (for example, carbon nanotube) or a particulate conductor on the base material. There has been proposed a conductive film removal method including a process, a process of heat treatment at 80 ° C. or higher, and a process of removing the conductive film by cleaning with a liquid. There has been proposed a conductive film removal method for removing the overcoat layer and the conductive film from a conductive film-containing substrate having an overcoat layer on the conductive film. When the conductive film removing agent is applied by heat treatment at 80 to 200 ° C., the conductive film in the portion where the conductive film removing agent is applied is decomposed, dissolved or solubilized, and has an overcoat layer. It is said that the overcoat layer and the conductive film are decomposed, dissolved or solubilized.

Special table 2008-547232 gazette Special table 2009-503825 gazette JP-T-2006-513557 Special Table 2007-529884 (International Publication No. 2005/086982 Pamphlet) International Publication 2010/113744 Pamphlet

  The carbon nanotube is exposed on the side surface (vertical wall surface) of the pattern formed by the technique using the conductive film removing agent of Patent Document 5. This is because even if an overcoat layer is provided on the upper surface of the carbon nanotube layer, the carbon nanotube layer and the overcoat layer are removed by the conductive film removing agent. That is, there is a carbon nanotube surface that is not covered with the overcoat layer. For this reason, a decrease in durability (for example, dropping of carbon nanotubes, change in physical properties due to moisture, etc.) can be considered.

  Furthermore, there may be a problem that the surface is uneven.

  The technique of Patent Document 5 requires a heating step of heating the conductive film remover applied in a predetermined pattern to 80 ° C. or higher. Therefore, workability is poor. Furthermore, the substrate is required to have a heat resistance of 80 ° C. or higher. This reduces the degree of freedom in substrate selection.

  The present invention aims to solve the above problems. In particular, the problem to be solved by the present invention is to provide a conductive (or insulating) film having high resolution and excellent durability by a simple method.

  The above-mentioned problems have been studied with eagerness.

  As a result, the following has been found. An overcoat layer was provided on a conductive film (for example, a conductive film formed by applying conductive carbon nanotubes). A resin-coated mask was placed and adhered onto the overcoat layer. Ultraviolet rays were irradiated in an oxygen-containing atmosphere through the mask adhered to the overcoat layer. The pattern thus formed had high pattern accuracy. The durability of the conductive film (insulating film) was excellent. Moreover, pattern formation was simple. The conductive film having a predetermined pattern is an insulating film having a predetermined pattern when viewed from the opposite standpoint.

  The present invention has been achieved based on the above findings.

The present invention
A method of forming a film with a predetermined pattern in which the conductive carbon layer in the ultraviolet irradiation region is modified to be insulative, and the conductive carbon layer in the non-ultraviolet irradiation region retains conductivity,
A step of providing a conductive carbon layer;
A step of providing an overcoat layer on the conductive carbon layer;
On the overcoat layer, a step in which at least the mask on the overcoat layer side is a resin is disposed;
Forming a film comprising: a step of irradiating the conductive carbon layer with ultraviolet rays from above the mask in a state where the mask is in close contact with the overcoat layer and in an atmosphere containing oxygen Suggest a method.

The present invention is the film forming method, wherein the overcoat layer is preferably composed of a composition containing at least one selected from the group of hydrolyzable hydrolyzable organosilanes. A film forming method is proposed.
The present invention proposes the film forming method, wherein the overcoat layer preferably has a thickness of 1 nm to 1 μm.

The present invention is the film forming method, wherein the mask preferably includes a shield having a predetermined pattern made of a shielding material that shields the ultraviolet rays, and a resin provided on a surface of the shield. A film forming method is proposed.
The present invention proposes the film forming method, wherein the resin is preferably at least one selected from the group consisting of a photocurable resin, a thermosetting resin, and a resist material. .
The present invention proposes a method of forming a film by pressurizing the mask and the overcoat layer.
The present invention proposes the film forming method, wherein the adhesion between the mask and the overcoat layer is performed by heating.
The present invention proposes a film forming method according to the film forming method, wherein the adhesion between the mask and the overcoat layer is performed by heating and pressing.

The present invention proposes the film forming method, wherein the ultraviolet ray is preferably an ultraviolet ray having a wavelength in the range of 10 to 400 nm.
The present invention proposes the film forming method, wherein the ultraviolet ray is preferably an ultraviolet ray having a wavelength in the range of 150 to 180 nm.
The present invention proposes a film forming method according to the above-mentioned film forming method, wherein the cumulative amount of irradiated ultraviolet light is preferably 50 to 500,000 mJ / cm ² .
The present invention proposes a film forming method according to the above-mentioned film forming method, wherein the cumulative amount of irradiated ultraviolet light is preferably 500 to 30000 mJ / cm ² .

The present invention proposes the film forming method, wherein the atmosphere containing oxygen preferably has an oxygen pressure of 101 to 21273 Pa.
The present invention proposes the film forming method, wherein the atmosphere containing oxygen preferably has an oxygen pressure of 1013 to 10130 Pa.

The present invention proposes the film forming method, wherein the conductive carbon layer is preferably composed of graphene.
The present invention proposes the film forming method, wherein the conductive carbon layer is preferably composed of carbon nanotubes.
The present invention proposes the above film forming method, wherein the conductive carbon layer is preferably composed of acid-treated single-walled carbon nanotubes.

  The present invention proposes a conductive film formed by the film forming method.

  The present invention proposes an insulating film formed by the film forming method.

  A conductive (or insulating) film with high resolution can be easily obtained.

Schematic sectional view showing the layer structure before UV irradiation Schematic sectional view showing the layer structure after UV irradiation Plan view of a pattern obtained by carrying out the present invention Schematic cross section of mask coated with resin Plan view of conductivity evaluation pattern

The first aspect of the present invention is a film forming method. The method is, for example, a method of forming a conductive film having a predetermined pattern. Alternatively, it is a method of forming an insulating film having a predetermined pattern. The method is a method of forming a transparent conductive film having a predetermined pattern. Alternatively, a transparent insulating film having a predetermined pattern is formed. The method is a film formation method of a predetermined pattern in which the conductive carbon layer in the ultraviolet irradiation region is modified to be insulative and the conductive carbon layer in the non-ultraviolet irradiation region retains conductivity. The above-described method is an insulating film forming method, particularly if the portion modified to be insulating is taken up. The above method is a method for forming a conductive film, particularly if the conductive part is taken up. The method includes the step of providing a conductive carbon layer. On the substrate, for example, conductive carbon (for example, conductive graphene (conductive carbon nanotube))-containing (for example, dispersed) paint is applied. By this coating, a conductive carbon layer is provided. A method other than the coating method may be used. For example, CVD (chemical vapor deposition method) and PVD (physical vapor deposition method) can be used. However, it is preferable to employ a coating method. The method includes a step of providing an overcoat layer on the conductive carbon layer. For example, an overcoat paint is applied on the conductive carbon layer. This coating forms an overcoat layer. The method includes a step of disposing a mask having a resin on the surface of at least the overcoat layer on the overcoat layer. The mask preferably includes a shield having a predetermined pattern made of a shielding material that shields the ultraviolet rays, and a resin provided on a surface of the shield. The resin may be provided only on one side of the shield (on the side facing the overcoat layer). The resin may be provided on the one surface side of the shield and only on the periphery of the shield. For example, the resin may not be provided in the central portion on the one surface side of the shield. The resin may be provided on one side and the other side of the shield (a surface facing the one surface). The resin may be a resin that can ensure adhesion with the overcoat layer. The resin is, for example, a photocurable resin. For example, a thermosetting resin. For example, a resist material. Adhesion between the mask and the overcoat layer is ensured, for example, by applying pressure. The adhesion between the mask and the overcoat layer is ensured, for example, by heating. The adhesion between the mask and the overcoat layer is ensured, for example, by heating and pressing. Adhesion between the overcoat layer and the mask was improved by using a resin-coated mask. Accordingly, it is difficult for ultraviolet rays to enter the boundary between the overcoat layer and the mask. In addition, active oxygen hardly enters the boundary between the overcoat layer and the mask. As a result, the pattern accuracy of the conductive film (insulating film) is increased. That is, a film having a high resolution pattern was obtained. The method includes a step of irradiating the conductive carbon layer with ultraviolet rays from above the mask in a state where the mask is in close contact with the overcoat layer and in an atmosphere containing oxygen. In this irradiation step, a resin-coated mask is brought into close contact with the conductive portion (for example, the wiring film portion), and ultraviolet rays are emitted to regions (insulating portions) other than the conductive portion (for example, the wiring film portion). Irradiated. Ultraviolet rays are irradiated to the portions that should be insulated. The ultraviolet non-irradiated region is a region where electrical conductivity should be ensured. The ultraviolet irradiation region is a region where conductivity should be lost. In order to form a conductive film (or insulating film) having a predetermined pattern, ultraviolet irradiation is performed. The overcoat layer is preferably composed of a composition containing at least one selected from the group of hydrolyzable organosilane hydrolysates. The ultraviolet rays are preferably ultraviolet rays having a wavelength in the range of 10 to 400 nm. More preferably, it is an ultraviolet ray having a wavelength in the range of 150 to 260 nm. Particularly preferred is ultraviolet light having a wavelength in the range of 150 to 180 nm. The atmosphere containing oxygen preferably has an oxygen pressure (in the case of a mixed gas, an oxygen partial pressure) of 101 to 21273 Pa. More preferably, the oxygen pressure is 507-20260 Pa. Particularly preferably, the oxygen pressure is 1013 to 10130 Pa. The conductive carbon layer is made of graphene, for example. The conductive carbon layer (graphene layer) is composed of, for example, carbon nanotubes. The conductive carbon layer (carbon nanotube layer) is composed of, for example, single-walled carbon nanotubes. The conductive carbon layer (carbon nanotube layer) is composed of, for example, single-walled carbon nanotubes subjected to acid treatment. The carbon nanotube is preferably a carbon nanotube of G (intensity at a Raman peak common to graphite substances appearing near 1590 cm ⁻¹ ) / D (intensity at a Raman peak due to defects appearing near 1350 cm ⁻¹ ) ≧ 10. . The upper limit value of G / D is about 150, for example.

  The second aspect of the present invention is a conductive film. The film is a conductive film formed by the film forming method.

The third aspect of the present invention is an insulating film. The film is an insulating film formed by the film forming method.
Further detailed description will be given below.

  1-4 is explanatory drawing of one Embodiment of this invention. 1 is a schematic cross-sectional view showing a layer structure before ultraviolet irradiation, FIG. 2 is a schematic cross-sectional view showing a layer structure after ultraviolet irradiation, FIG. 3 is a plan view of a pattern obtained by carrying out the present invention, and FIG. 4 is a resin It is a schematic sectional drawing of a coating mask.

1 is a transparent conductive carbon layer.
The transparent conductive carbon layer 1 is made of graphene, for example.
The transparent conductive carbon layer 1 was made of carbon nanotubes, for example.
The transparent conductive carbon layer 1 was composed of, for example, single-walled carbon nanotubes.
The transparent conductive carbon layer 1 is composed of, for example, single-walled carbon nanotubes that have been subjected to acid treatment.

Examples of the carbon nanotubes (CNT) constituting the transparent conductive carbon layer 1 include single-walled carbon nanotubes, double-walled carbon nanotubes, and multi-walled carbon nanotubes.
Single-walled carbon nanotubes are preferred. In particular, single-walled carbon nanotubes having a G / D of 10 or more (for example, 20 to 60) are preferable.
CNTs having a diameter of 0.3 to 100 nm are preferable. In particular, CNT having a diameter of 0.3 to 2 nm is preferable.
CNTs with a length of 0.1-100 μm are preferred. In particular, CNT having a length of 0.1 to 5 μm is preferable.
The CNTs in the transparent conductive carbon layer 1 are intertwined with each other, for example.

The single-walled carbon nanotube may be a single-walled carbon nanotube obtained by any manufacturing method. For example, single-walled carbon nanotubes obtained by a production method such as arc discharge, chemical vapor deposition, or laser evaporation can be used.
From the viewpoint of crystallinity, single-walled carbon nanotubes obtained by an arc discharge method are preferred. This is easily available.
The single-walled carbon nanotube is preferably a single-walled carbon nanotube subjected to acid treatment. The acid treatment is performed by immersing single-walled carbon nanotubes in an acidic liquid. A technique called spraying may be employed instead of immersion. There are various types of acidic liquids. For example, an inorganic acid or an organic acid is used. However, inorganic acids are preferred. For example, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, or a mixture thereof can be used. Among these, acid treatment using nitric acid or a mixed acid of nitric acid and sulfuric acid is preferable. By this acid treatment, when the single-walled carbon nanotube and the carbon fine particles are physically bonded via the amorphous carbon, the amorphous carbon is decomposed. Both separated. The fine particles of the metal catalyst used in the production of the single-walled carbon nanotube were decomposed. A functional group is attached by the acid treatment. The conductivity was improved by the acid treatment.
The single-walled carbon nanotube is preferably a single-walled carbon nanotube in which impurities are removed by filtration and purity is improved. This is because a decrease in conductivity and a decrease in light transmittance due to impurities are prevented. Various methods are employed for filtration. For example, suction filtration, pressure filtration, cross flow filtration and the like are used. Among these, from the viewpoint of scale-up, it is preferable to employ cross flow filtration using a hollow fiber membrane.

The conductive layer (carbon nanotube layer) 1 preferably contains fullerene in addition to the CNT.
The conductive layer 1 preferably contains the above-mentioned CNT and fullerene.
In the present specification, “fullerene” includes “fullerene analog”.
This is because heat resistance is improved by including fullerene. It is because it was excellent also in electroconductivity.
The fullerene may be any fullerene. For example, C60, C70, C76, C78, C82, C84, C90, C96 etc. are mentioned. Of course, a mixture of plural kinds of fullerenes may be used.
C60 is particularly preferable from the viewpoint of dispersion performance. Furthermore, C60 is easy to obtain. Not only C60 but also a mixture of C60 and another kind of fullerene (for example, C70) may be used.
The fullerene may contain metal atoms.
Examples of the fullerene analog include those having a functional group (for example, a functional group such as OH group, epoxy group, ester group, amide group, sulfonyl group, ether group). Examples also include phenyl-C61-propyl acid alkyl ester and phenyl-C61-butyric acid alkyl ester. Examples thereof include hydrogenated fullerene. Among them, fullerene having an OH group (hydroxyl group) (fullerene hydroxide) is preferable. This is because the dispersibility during coating of the single-walled carbon nanotube dispersion was high. When the number of OH groups is small, the degree of improvement in dispersibility of the single-walled carbon nanotube is lowered. On the other hand, if too much, synthesis is difficult. Accordingly, the number of OH groups is preferably 5 to 30 per molecule of fullerene. In particular, 8 to 15 are preferable. When there is too much addition amount (content) of fullerene, electroconductivity will fall. Conversely, if the amount is too small, the effect is poor. Therefore, the amount of fullerene is preferably 10 to 1000 parts by mass (particularly 20 parts by mass or more and 100 parts by mass or less) with respect to 100 parts by mass of CNT.

  The transparent conductive carbon layer (carbon nanotube layer) 1 may contain a binder resin. However, from the viewpoint of conductivity, it is preferable not to include a binder resin. For example, when entangled CNTs are used, there is no need for a binder resin. The CNTs that are intertwined are in direct contact with each other. Since there is no insulator between them, the conductivity is good. If the surface of the conductive film is observed with a scanning electron microscope, it can be confirmed / determined whether the structure is intertwined with CNTs.

  The transparent conductive carbon layer 1 is configured by applying a CNT dispersion liquid (a dispersion liquid in which CNT having the above characteristics and fullerene added as necessary are dispersed) on the substrate 2. Examples of the coating method include die coating, knife coating, spray coating, spin coating, slit coating, micro gravure, flexo and the like. Of course, it is not limited to this. The carbon nanotube dispersion liquid is applied to the entire surface of the substrate 2. The transparent conductive carbon layer (carbon nanotube layer) 1 is preferably formed uniformly in order to uniformly promote insulation during ultraviolet irradiation.

  Various materials are appropriately used as the constituent material of the substrate 2. For example, polystyrene (PS), polymethyl methacrylate (PMMA), styrene-methyl methacrylate copolymer (MS), polycarbonate (PC), cycloolefin polymer (COP), cycloolefin copolymer (COC), polyethylene terephthalate (PET), A resin such as polyethylene naphthalate (PEN) is used. In the present invention, since heating is not required for pattern formation, the degree of required heat resistance is low. Therefore, even when a resin is used as the constituent material of the substrate 2, the degree of freedom in resin selection is high. In addition to the resin, an inorganic glass material or a ceramic material can be used.

In the present invention, the overcoat layer (protective layer) 3 is provided on the transparent conductive carbon layer 1.
The overcoat layer 3 is composed of an organic polymer material, an inorganic polymer material, an organic-inorganic hybrid resin, or the like.
Examples of organic polymer materials include thermoplastic resins, thermosetting resins, cellulose resins, and photocurable resins. It is appropriately selected from the viewpoints of visible light transmittance, substrate heat resistance, glass transition point, film curing degree, and the like. Examples of the thermoplastic resin include polymethyl methacrylate, polystyrene, polyethylene terephthalate, polycarbonate, polylactic acid, and ABS resin. Examples of the thermosetting resin include phenol resin, melamine resin, alkyd resin, polyimide, epoxy resin, fluorine resin, and urethane resin. Examples of the cellulose resin include acetyl cellulose and triacetyl cellulose. Examples of the photocurable resin include various oligomers, monomers, resins containing a photopolymerization initiator, and the like.
Examples of the inorganic material include silica sol, alumina sol, zirconia sol, titania sol and the like. Examples thereof include a polymer obtained by hydrolyzing and dehydrating and condensing water or an acid catalyst to the inorganic material.
Examples of the organic-inorganic hybrid resin include a resin in which a part of the inorganic material is modified (for example, substituted or added) with an organic functional group, or a resin mainly composed of various coupling agents such as a silane coupling agent. Etc.
If the overcoat layer 3 is too thick, the contact resistance of the conductive film increases. On the contrary, if the overcoat layer 3 is too thin, it is difficult to obtain an effect as a protective film. Therefore, the thickness of the overcoat layer 3 is preferably 1 nm to 1 μm. In particular, 10 nm or more is preferable. 200 nm or less is preferable. Furthermore, 150 nm or less is preferable.

The overcoat layer 3 provided on the transparent conductive carbon layer (carbon nanotube layer) 1 is particularly preferably composed of a composition containing, for example, a hydrolyzate of hydrolyzable organosilane.
Preferably, it consists of a composition containing a tetrafunctional hydrolyzable organosilane.
In particular, it comprises a composition containing a hydrolyzate of a tetrafunctional hydrolyzable organosilane and a hydrolyzable organosilane having an epoxy group and an alkoxy group.
Among these, the content of the hydrolyzable organosilane hydrolyzate having an epoxy group and an alkoxy group is preferably 1 to 10% by weight based on the total solid content of the resin.
When a hydrolyzable organosilane cohydrolyzate having an epoxy group and an alkoxy group is contained, the epoxy group of the cohydrolyzate is a hydroxyl group contained in the substrate when the composition is applied and cured. And oxygen sites such as carbonyl groups. For this reason, the adhesion between the overcoat layer (protective film) and the transparent conductive carbon layer (carbon nanotube layer) 1 is improved.
It consists of a composition containing silica-based metal oxide fine particles. In some cases, the composition further comprises a hydrolyzate of hydrolyzable organosilane having a fluorine-substituted alkyl group.
The hydrolyzate of the hydrolyzable organosilane is preferably a product obtained by reacting at a water ratio of 1.0 to 3.0 with respect to the alkoxy group contained in the hydrolyzable organosilane.
The hydrolyzate of the hydrolyzable organosilane is preferably a compound having a polystyrene equivalent weight average molecular weight of 1000 to 2000.

The tetrafunctional hydrolyzable organosilane is a compound represented by, for example, SiX ₄ . X is a hydrolyzable group. For example, an alkoxy group, an acetoxy group, an oxime group, an enoxy group, and the like. In particular, it is a tetrafunctional hydrolyzable organoalkoxysilane represented by Si (OR ¹ ) ₄ . R ¹ is preferably a monovalent hydrocarbon group. For example, it is a monovalent hydrocarbon group having 1 to 8 carbon atoms. For example, it is a C1-C8 alkyl group (methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group). Examples of the tetrafunctional hydrolyzable organosilane used in the present embodiment include tetramethoxysilane and tetraethoxysilane. The hydrolyzable organosilane having an epoxy group and an alkoxy group is, for example, a compound represented by R ² Si (OR ³ ) ₃ or R ² R ⁴ Si (OR ³ ) ₂ . R ² is a group selected from an epoxy group, a glycidoxy group, and substituted products thereof. R ³ is a monovalent hydrocarbon group as in R ¹ . For example, methyl group, ethyl group, propyl group, butyl group, pentyl group and the like. R ⁴ is a group selected from hydrogen, an alkyl group, a fluoroalkyl group, an aryl group, an alkenyl group, a methacryloxy group, an epoxy group, a glycidoxy group, an amino group, and substituents thereof.
Examples of the hydrolyzable organosilane having an epoxy group and an alkoxy group used in this embodiment include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and γ-glycidoxypropyltrisilane. Examples thereof include ethoxysilane and γ-glycidoxypropyldimethoxymethylsilane.
As silica-based metal oxide fine particles, hollow silica fine particles are preferably used. The hollow silica fine particles are those in which cavities are formed inside the outer shell of the silica-based metal oxide. The outer shell is preferably a porous one having pores. It may be one in which the pores are closed and the cavity is sealed. As long as it contributes to lowering the refractive index of the formed film, it is not necessarily limited to the hollow silica described above.

  In the case of the overcoat layer having such a composition, the light reflectance was lowered and the light transmittance was high. High physical protection against friction. Protection was high against environmental changes such as heat and humidity. When such an overcoat layer 3 was provided, it was confirmed that the transparent conductive carbon layer (carbon nanotube layer) 1 was modified from conductive to insulating by ultraviolet irradiation in a short time. In the present invention, such an overcoat layer is provided on the transparent conductive carbon layer (carbon nanotube layer) 1 prior to the ultraviolet irradiation step.

  The overcoat layer 3 is provided by applying a paint containing the above composition. As the application method, the method described in the application of the CNT dispersion liquid is employed. The coating is performed on the conductive layer (carbon nanotube layer). Moreover, it is applied to the entire surface. It is preferable that the overcoat layer 3 is also formed uniformly in order to make the insulation at the time of ultraviolet irradiation progress uniformly.

Reference numeral 4 denotes a mask coated with a resin.
The entire surface of the mask may be coated with a resin.
Only the surface on the overcoat layer 3 side may be coated with a resin.
Instead of the entire surface on the overcoat layer 3 side, it may be partially (peripheral) covered. However, full coverage will be easier than partial coverage. Therefore, preferably, at least the surface on the overcoat layer 3 side is coated with a resin. Of course, there may be some coating leakage.

The mask 4 coated with a resin includes a shield 5 having a predetermined pattern made of a shielding material that shields ultraviolet rays, and a resin layer 6 coated (applied) on the surface of the shield 5.
The shield 5 is made of a material that does not transmit the ultraviolet rays. For example, it is made of metal. Specifically, Au, Ag, Cu, Al, stainless steel, etc. are mentioned. Of course, it is not limited to this. Furthermore, materials other than metal may be used.
Examples of the resin include a photocurable resin and a thermosetting resin. In addition, a resist material can also be used. Examples of the photocurable resin include acryloyl group-modified resins. Examples of the thermosetting resin include an epoxy resin. Examples of the resist material include novolak resin and melamine resin.
The resin may be one that transmits ultraviolet light or one that does not transmit ultraviolet light. When a resin that does not transmit ultraviolet rays is used, the resin does not close the opening 7 of the shield 5.
By providing the resin layer on the surface of the shield 5, the adhesion between the mask 4 and the overcoat layer 3 was improved. By improving the adhesion between the mask 4 and the overcoat layer 3, leakage of ultraviolet rays (around) to the portion where conductivity is desired to be maintained, and leakage of active oxygen such as ozone generated from oxygen present in the atmosphere (entrance) Is prevented. Thereby, the precision of patterning increased.
Examples of the mask include a suspend metal mask in which a nickel foil is attached on a stainless steel mesh, and a metal mask in which an opening is opened by laser or etching.
The mask 4 and the overcoat layer 3 are heated, for example (temperature at which the resin softens: for example, 80 to 100 ° C., and may be a temperature lower than 80 ° C.) and pressed (crimping: the mask 4 and Any pressure may be used as long as it is in close contact with the overcoat layer 3. For example, about 100 to 1000 g / m ² .

The transparent conductive carbon layer (carbon nanotube layer) 1 was irradiated with ultraviolet rays. This ultraviolet ray preferably has a wavelength of 10 to 400 nm. More preferably, the wavelength is 150 to 260 nm. Particularly preferably, the wavelength is 150 to 180 nm. More preferably, the wavelength is 160 to 175 nm. For example, when ultraviolet rays having a long wavelength exceeding 400 nm are irradiated, denaturation from conductive carbon nanotubes to insulating carbon nanotubes hardly occurs. By the way, it was difficult for the denaturation to occur when the high pressure mercury lamp used in a normal photolithography process was irradiated with ultraviolet rays (wavelength: 365 nm). In order to denature conductive carbon nanotubes into insulating carbon nanotubes, it was more preferable that the irradiated ultraviolet light had a wavelength of 260 nm or less. More preferably, the ultraviolet ray was 180 nm or less. For example, when irradiated with ultraviolet light (wavelength: 185 nm, 254 nm) from a low-pressure mercury lamp, the carbon nanotubes were easily denatured from conductive to insulating at the irradiated site. However, when the substrate 2 is made of resin, the substrate 2 sometimes has a phenomenon called discoloration. For this reason, it was particularly preferable that the irradiated ultraviolet light has a wavelength of 180 nm or less, and further 175 nm or less. For example, ultraviolet rays (wavelength: 172 nm) from a xenon excimer lamp were particularly preferable. The time of ultraviolet irradiation having the above characteristics is, for example, about 10 seconds to 1 hour. Preferably, it is 1 minute or longer. Preferably, it is 40 minutes or less. The cumulative amount of UV irradiation was, for example, about 50 to 500,000 mJ / cm ² . Preferably, it was about 100 to 100,000 mJ / cm ² . More preferably, it was 500-30,000 mJ / cm < ² >. The preferable integrated light amount varies somewhat depending on the thickness of the carbon nanotube layer 1. It varied greatly depending on the presence or absence of the overcoat layer. With the overcoat layer, the carbon nanotubes were modified from conductive to insulating in a short time. It also varied depending on the type and thickness of the overcoat layer. When the overcoat layer was a composition containing a hydrolyzate of hydrolyzable organosilane, the irradiation time was significantly shortened. The thickness of the overcoat layer 3 was preferably 10 to 200 nm. More preferably, it was 50-150 nm. 1a is an ultraviolet irradiation location. The ultraviolet irradiation part 1a is denatured to be insulating. Reference numeral 1b denotes a portion not irradiated with ultraviolet rays. The portion 1b not irradiated with ultraviolet rays remains conductive.

  It was preferable that oxygen (or active oxygen) was present in the atmosphere at the time of ultraviolet irradiation. Even when UV irradiation was performed, no modification of the transparent conductive carbon layer (carbon nanotube layer) 1 from conductivity to insulation was observed in an oxygen-free state. The atmosphere containing oxygen preferably had an oxygen pressure of 101 to 21273 Pa. More preferably, the oxygen pressure was 507-20260 Pa. Particularly preferably, the oxygen pressure was 1013 to 10130 Pa.

  The transparent conductive carbon layer (carbon nanotube layer) 1 becomes a conductive (or insulating) film having a predetermined pattern by ultraviolet irradiation. The present invention and the conventional pattern forming method are greatly different. That is, the overcoat layer (coating layer) 3 remains as it is. The conductive layer (insulating layer) remains covered with the overcoat layer 3. Not exposed. As a result, the protective effect of the conductive layer (insulating layer) is high. That is, the durability is high. For example, the conductive layer (insulating layer) is hardly chipped (dropped off). It is difficult for moisture (humidity) to enter the conductive layer (insulating layer). In order to obtain a conductive film having a predetermined pattern, there is no need to remove (etch away) the transparent conductive carbon layer (carbon nanotube layer) 1. Because it is not necessary to use chemicals for removal, it is environmentally friendly. A conductive film (insulating film) was obtained by a very simple operation.

  Hereinafter, description will be made with specific examples. The present invention is not limited to the following examples.

[Example 1]
The single wall carbon nanotubes (commercially available) synthesized by arc discharge were subjected to acid treatment, water washing, centrifugation and filtration. A surfactant (sodium dodecylbenzenesulfonate: SDBS) 0.2 wt% aqueous solution was added to the purified carbon nanotubes. The carbon nanotube-containing aqueous solution was subjected to a dispersion treatment using an ultrasonic device. Centrifugation was then performed. Thus, a carbon nanotube dispersion liquid (CNT: 3200 ppm) was obtained.

  The carbon nanotube dispersion was applied onto the substrate 2. The substrate 2 is a PET film (MKZ-T4A: manufactured by Higashiyama Film). The application method is die coating. The coating thickness is 0.05 μm (thickness after drying). After application, ion exchange water cleaning was performed. Thereby, the surfactant contained in the coating film (carbon nanotube layer) was removed. This was followed by drying (1.5 minutes; 120 ° C.). Thus, the carbon nanotube layer (transparent conductive carbon layer) 1 was provided on the PET film 2.

  An overcoat layer 3 was provided on the carbon nanotube layer 1. For the construction of the overcoat layer 3, 1.8 wt% Aerocera (hydrolyzable organosilane-containing composition: manufactured by Panasonic Corporation) was used. The application method is die coating. The coating thickness was 0.1 μm (thickness after drying).

A mask 4 was placed on the overcoat layer 3. The mask 4 has a structure in which a resist (G63: resin) layer 6 is coated on the surface of a metal (Ni) mask (ultraviolet shield) 5. An opening 7 having a predetermined pattern is formed in the metal mask (ultraviolet shield) 5. Ultraviolet light can pass through the opening 7. The opening (ultraviolet transmission part) 7 has a square shape with a line width of 100 μm and a side length of 5 mm.
The resist layer 6 of the mask 4 and the overcoat layer 3 were brought into close contact with each other. That is, the mask 4 disposed on the overcoat layer 3 was heated to 100 ° C. During this heating, the mask 4 was pressed (pressed) to the overcoat layer 3 side.

Thereafter, ultraviolet rays were irradiated from above the mask 4. Ultraviolet rays are ultraviolet rays (wavelength: 172 nm) from a xenon excimer lamp. The atmosphere during ultraviolet irradiation was 94% nitrogen and 6% oxygen. The pressure by the mixed gas is 1.013 × 10 ⁵ Pa.

  The continuity between the inside and outside of the □ -shaped opening 7 was examined with a tester. As a result, it was found that there was no conduction (insulation) between the two.

  The pattern shape (□ shape) of the opening 7 of the mask 4 was compared with the pattern shape (□ shape) of the carbon nanotube conductive layer. The agreement between the two was extremely high. That is, the transparent conductive film was formed with high accuracy.

  For conductivity evaluation, the conductivity evaluation pattern shown in FIG. 5 was formed in the same manner as the above-mentioned □ shape pattern. In this pattern, the portion corresponding to the metal mask (ultraviolet shield) is the conductive portion 51, and the portion corresponding to the opening is the insulating portion 71. The inter-terminal resistance values at both ends of the conductive portion 51 in the conductive evaluation pattern were measured with a tester. As a result, the resistance value between terminals was about 20 kΩ. At this time, the width of the thin line portion in the conductive film was 680 μm, while the width of the thin line portion in the resin film was 686 μm.

[Example 2]
The same procedure was performed except that a mask having the following structure was used instead of the mask used in Example 1. The mask used in this example has a structure in which a Ni film is provided on stainless steel and a resist (SR300s: resin) layer is coated on the Ni film.

  The continuity between the inside and outside of the □ -shaped opening was examined with a tester. As a result, it was found that there was no conduction (insulation) between the two.

  The pattern shape (□ shape) of the opening of the mask was compared with the pattern shape (□ shape) of the carbon nanotube conductive layer. The agreement between the two was extremely high. That is, the transparent conductive film was formed with high accuracy.

  For conductivity evaluation, the conductivity evaluation pattern shown in FIG. 5 was formed in the same manner as the above-mentioned □ shape pattern. The resistance value between terminals at both ends of the conductive portion 51 of the conductive evaluation pattern was measured with a tester. As a result, the resistance value between terminals was about 20 kΩ.

[Comparative Example 1]
In Example 1, it carried out similarly except having set it as nitrogen atmosphere (oxygen partial pressure 0Pa: no oxygen).

  In Comparative Example 1, the ultraviolet irradiation site was not modified from conductive to insulating.

[Comparative Example 2]
In Example 1, it carried out similarly except that the overcoat layer 3 was not provided.

  Even in Comparative Example 2, the ultraviolet irradiation site was not modified from conductive to insulating.

[Comparative Example 3]
In Example 1, it was performed in the same manner except that a mask not coated with resin (a mask made of only metal) was used and no heating / pressurization was performed.

The continuity between the inside and outside of the □ -shaped opening was examined with a tester.
As a result, it was found that there was no conduction (insulation) between the two.
The pattern shape (□ shape) of the mask opening was compared with the pattern shape (□ shape) of the carbon nanotube conductive layer. As a result, the insulated part was wider than the mask opening. That is, the formation accuracy of the transparent conductive pattern was low.

  A conductive evaluation pattern was formed on the conductive film in the same manner as the square shape pattern except that the metal mask pattern was changed to the conductive evaluation pattern shown in FIG. The resistance value between terminals at both ends of the conductive portion 51 of the pattern was measured with a tester. As a result, the resistance value between the terminals was 356 kΩ, and the resistance value was larger than that of the example.

1 Transparent conductive carbon layer (carbon nanotube layer)
1a UV irradiation location (insulation modified location)
1b UV-irradiated area (transparent conductive area)
2 Substrate 3 Overcoat layer (hydrolyzable organosilane-containing composition layer)
4 Mask 5 UV shield 6 Resin layer (resist layer)
7 Opening (UV transmitting part)
51 Conducting part 71 Insulating part 8 Fine wire part

Claims (19)

A method of forming a film with a predetermined pattern in which the conductive carbon layer in the ultraviolet irradiation region is modified to be insulative, and the conductive carbon layer in the non-ultraviolet irradiation region retains conductivity,
A step of providing a conductive carbon layer;
A step of providing an overcoat layer on the conductive carbon layer;
On the overcoat layer, a step in which at least the mask on the overcoat layer side is a resin is disposed;
Forming a film comprising: a step of irradiating the conductive carbon layer with ultraviolet rays from above the mask in a state where the mask is in close contact with the overcoat layer and in an atmosphere containing oxygen Method. 2. The film forming method according to claim 1, wherein the overcoat layer is composed of a composition containing at least one selected from the group of hydrolyzable hydrolyzable organosilanes. The film formation method according to claim 1, wherein the overcoat layer has a thickness of 1 nm to 1 μm. The mask is
A shield of a predetermined pattern made of a shielding material that shields the ultraviolet rays, and
The film forming method according to claim 1, further comprising: a resin provided on a surface of the shield. 5. The film forming method according to claim 1, wherein the resin is at least one selected from the group consisting of a photocurable resin, a thermosetting resin, and a resist material. The film forming method according to claim 1, wherein the adhesion between the mask and the overcoat layer is applied by pressure. The film forming method according to claim 1, wherein the adhesion between the mask and the overcoat layer is by heating. 6. The film forming method according to claim 1, wherein the adhesion between the mask and the overcoat layer is performed by heating and pressing. The film forming method according to any one of claims 1 to 8, wherein the ultraviolet ray is an ultraviolet ray having a wavelength in a range of 10 to 400 nm. The film forming method according to any one of claims 1 to 8, wherein the ultraviolet ray is an ultraviolet ray having a wavelength in a range of 150 to 180 nm. 11. The film forming method according to claim 1, wherein the cumulative amount of irradiation with ultraviolet light is 50 to 500,000 mJ / cm ² . 11. The film forming method according to claim 1, wherein an integrated irradiation light quantity of the ultraviolet rays is 500 to 30000 mJ / cm ² . The film forming method according to any one of claims 1 to 12, wherein the atmosphere containing oxygen has an oxygen pressure of 101 to 21273 Pa. The film forming method according to claim 1, wherein the atmosphere containing oxygen has an oxygen pressure of 1013 to 10130 Pa. The film forming method according to claim 1, wherein the conductive carbon layer is made of graphene. The film forming method according to claim 1, wherein the conductive carbon layer is composed of carbon nanotubes. The film forming method according to any one of claims 1 to 16, wherein the conductive carbon layer is composed of acid-treated single-walled carbon nanotubes.   A conductive film formed by the film forming method according to claim 1. An insulating film formed by the film forming method according to claim 1.

Images