JP5760676B2 - Process for producing patterned metal film - Google Patents

Description

  The present invention relates to a method for producing a patterned metal film by etching a metal film. Specifically, the present invention relates to a method for producing a patterned metal film that can be used for a conductive film, an electromagnetic wave shielding film, or circuit wiring.

  As a method for producing a mesh-like metal pattern of a conductive film or an electromagnetic wave shielding film or a metal pattern of circuit wiring, a patterned resist film is formed on the metal film by a photolithography method or a printing method, and then the metal film is etched. The method is known.

  In addition, it is also known to perform over-etching (etching until the line width of the metal film becomes smaller than the line width of the patterned resist film) in the etching process of the metal film (for example, Patent Document 1).

  The resist film formed on the metal film is designed to have a relatively high pencil hardness in consideration of etching resistance and the like. For example, as described in Patent Documents 2 to 5, the pencil hardness of the resist film is generally H or HB.

International Publication No. 2006/137229 Pamphlet JP-A-8-176886 Japanese Patent Laid-Open No. 8-21602 JP-A-10-231326 JP 2009-300533 A

  As described above, it is known to over-etch a metal film, but the pencil hardness of a conventional general resist film is relatively hard, such as H or HB or higher. In such a technical background, when the thickness of the patterned resist film formed on the metal film is relatively small (for example, 5 μm or less) and overetching is performed, the resist film is partially broken in the etching process. The problem of missing. When the resist film is partially broken, the etching of the portion proceeds excessively, resulting in a problem that a desired metal pattern cannot be obtained.

  Accordingly, an object of the present invention is to stably produce a metal film having a desired pattern in a method for producing a patterned metal film in which the thickness of the resist film is relatively reduced and overetched in view of the above-described problems of the prior art. An object of the present invention is to provide a method for producing a patterned metal film.

The above object of the present invention has been basically achieved by the following invention.
1) A method for producing a patterned metal film, which includes a step (A) of forming a patterned resist film on the metal film and a step (B) of etching the metal film,
The resist film has a thickness of 0.5 μm or more and 5 μm or less and a pencil hardness of B or less,
A method for producing a patterned metal film, wherein in the step (B), overetching is performed by chemical etching so that the line width of the metal film is 80% or less with respect to 100% of the line width of the resist film.
2) The method for producing a patterned metal film according to 1), wherein the step (A) forms a patterned resist film on the metal film by a printing method.
3) The method for producing a patterned metal film according to 2), wherein the printing method is a gravure printing method.
4) The method for producing a patterned metal film according to any one of 1) to 3), wherein the resist film is obtained by curing an active energy ray-curable resist film forming composition.

  5) The method for producing a patterned metal film according to 4), wherein the composition for forming an active energy ray-curable resist film includes at least the following component a and the following component b.

Component a: Monomer and / or oligomer component b having at least one ethylenically unsaturated group and at least one ethyleneoxy group in one molecule; having at least one carboxyl group in one molecule Resin having an acid value of 50 or more and less than 200 6) The patterned metal film according to any one of 1) to 5), further including a step of peeling and removing the resist film after the step (B). Manufacturing method.

  According to the present invention, a high-definition metal pattern can be stably manufactured at a low cost by a combination of thinning of a resist film (thickness of 5 μm or less) and over-etching.

The schematic front view of the state by which the patterned resist film was formed on the metal film by the patterned resist film formation process (A) of this invention. The YY schematic cross section of FIG. The schematic cross section which shows the state over-etched by the etching process (B) of this invention. The schematic plan view which shows the relationship between the resist film at the time of overetching, and a metal film.

  The method for producing a patterned metal film according to the present invention includes a step (A) of forming a patterned resist film on the metal film and a step (B) of etching the metal film. In the following description, the step (A) of forming a patterned resist film on the metal film is simply referred to as a resist film forming step (A), and the step of etching the metal film (B) is simply referred to as an etching step (B). .

  Examples of the material constituting the metal film used in the present invention include metals and metal compounds, and it is essential that any of these materials can be etched. Examples of metals or metal compounds include metals such as copper, aluminum, nickel, iron, gold, silver, indium, antimony, tin, and zinc, and metal compounds such as oxides, nitrides, sulfides, and carbides of the above metals. Can be mentioned. Furthermore, as a material constituting the metal film, a composite material of the metal or the metal compound (for example, indium tin oxide (ITO), antimony tin oxide (ATO), or the like) can be given.

  The metal film preferably has electrical conductivity, and the surface resistance value of the metal film is preferably 500Ω / □ or less, more preferably 300Ω / □ or less, further preferably 100Ω / □ or less, and particularly preferably 50Ω / □ or less. The lower limit is about 0.005Ω / □.

  The metal film may be a single film or a laminated film. The thickness of the metal film is suitably in the range of 0.01 to 20 μm, but the present invention is suitable when the thickness of the metal film is relatively small, specifically 10 μm or less, more preferably 5 μm or less, It is more preferably 3 μm or less, and particularly preferably 2 μm or less. The lower limit is preferably 0.01 μm or more.

  When the thickness of the metal film is relatively small as described above, the etching time in the etching step (B) is relatively short, which is effective in suppressing partial breakage of the resist film during overetching.

  The metal film is preferably used in a state of being laminated on a suitable base material such as a glass plate, a plastic plate, or a plastic film. As a method of laminating a metal film on a base material, a method in which the base material and the metal film are bonded with an adhesive or the like, a plating method or a gas phase film forming method (sputtering, ion plating, electron directly on the base material). And a method of forming a metal film by beam evaporation, vacuum evaporation, chemical vapor deposition, or the like. Among these, the vapor deposition method is preferably used from the viewpoint of uniformly and stably laminating a metal film having a relatively small thickness.

  The pattern shape in the patterned resist film and the patterned metal film is not particularly limited to a specific shape, for example, a lattice pattern used for an electromagnetic shielding film, a circuit pattern used for a printed wiring board, An electrode pattern such as a touch panel can be used.

  In the resist film forming step (A), as a method for forming a patterned resist film on the metal film, for example, a photolithography method or a printing method can be used.

  The method of forming a patterned resist film on a metal film by the photolithography method is to laminate a resist film on the metal film and expose it through a photomask having a desired pattern, or directly scan and expose with a laser, This is a method for forming a patterned resist film by developing. As a method of laminating the resist film on the metal film, for example, a method of attaching a resist film on the metal film or a method of applying a liquid resist is used.

  The method of forming a patterned resist film on a metal film by the printing method is a method of printing a resist film on a metal film in a pattern. Examples of such a printing method include a relief printing method, a lithographic printing method, an intaglio printing method, and a stencil printing method. Among these, the intaglio printing method and the stencil printing method are preferable, and the intaglio printing method is more preferably used.

  Among the resist film forming methods, a printing method is preferable from the viewpoint of productivity, and among the printing methods, an intaglio printing method is preferable because a pattern can be continuously formed by a roll-to-roll method.

  As the intaglio printing method, a gravure printing method is particularly preferable. Among gravure printing methods, there are direct gravure printing method and offset gravure printing method, both of which are preferably used, but the direct gravure printing method is a roll-to-roll method in particular that provides a stable and continuous pattern. It is preferable because a resist film can be formed.

  After a resist film having a predetermined pattern is formed on the metal film in the resist film formation step (A), the portion of the metal film not covered with the resist film is etched (dissolved and removed) in the etching step (B). Then, a patterned metal film is formed.

  The etching method used in the etching step (B) is not particularly limited, but a chemical etching method is preferably used. The chemical etching method is a method in which an unnecessary metal film portion other than a metal film portion protected by a resist film is dissolved and removed with an etching solution. Examples of the etching solution used for the chemical etching method include an aqueous ferric chloride solution, an aqueous cupric chloride solution, and an alkaline etching solution.

  The temperature of the etching solution in the etching step (B) is suitably in the range of 20-60 ° C, and preferably in the range of 25-50 ° C. The treatment time is suitably in the range of 10 to 300 seconds, and preferably in the range of 20 to 180 seconds.

  In the present invention, it is important that overetching is performed in the etching step (B). Hereinafter, over-etching in the present invention will be described.

  FIG. 1 is a schematic front view showing a state in which a patterned resist film is formed on a metal film in the resist film forming step (A), and FIG. 2 is a YY schematic cross-sectional view of FIG. FIG. 3 is a schematic cross-sectional view when overetching is performed.

  1 and FIG. 2 in which a patterned resist film is formed on the metal film, the portion of the metal film 1 that is not covered with the resist film 2 is etched, and the resist film pattern and A metal film having a similar pattern can be obtained. In this etching step (B), etching until the line width M of the metal film 1 becomes smaller than the line width L of the resist film 2 as shown in FIG.

  The present invention is characterized in that overetching is performed until the line width of the patterned metal film becomes 80% or less with respect to the line width of 100% of the patterned resist film. That is, when the line width L of the patterned resist film 2 in FIG. 3 is 100%, overetching is performed until the line width M of the patterned metal film 1 becomes 80% or less.

  Hereinafter, the ratio (%) of the line width of the patterned metal film to the line width of 100% of the patterned resist film is referred to as the over-etching rate. That is, the overetching rate in the present invention is 80% or less.

  The cross-sectional shape of the line of the over-etched patterned metal film may be trapezoidal or curved, and the width may be different in the thickness direction of the patterned metal film 1. Therefore, in the present invention, the line width of the patterned metal film can be obtained by, for example, enlarging the surface using a digital microscope or the like, observing the surface, and measuring the line width using the length measurement function.

  Similarly, the line width of the patterned resist film can also be obtained by enlarging the surface using a digital microscope or the like, observing the surface, and measuring the line width using the length measurement function.

  The over-etching ratio is measured by measuring the line width of the patterned resist film in the region where the line width is the same (the line width of the patterned resist film is measured in the region where the designed line width is the same). In addition, by measuring the line width in the region of the patterned metal film corresponding to the region of the patterned resist film whose line width was measured (corresponding to the region of the patterned resist film whose line width was measured, Measure and calculate the line width of the patterned metal film in the region with the same line width in the design.

  For example, a grid pattern used for an electromagnetic wave shielding film or the like is usually configured with the same grid pattern (a grid pattern designed so that the line width and pitch are the same) throughout the electromagnetic wave shielding film. The line width of the patterned resist film and the line width of the patterned metal film can be measured at arbitrary positions to calculate the overetching rate.

  On the other hand, in the case of a pattern in which a plurality of areas having different line widths are mixed, such as a circuit pattern or an electrode pattern (in the case of a pattern having a plurality of line widths by design), the pattern is formed within the same line width. Then, the line width of the patterned resist film is measured (by measuring the line width of the patterned resist film in the region where the same line width is designed by design), and then the line width of the patterned resist film is measured. Then, the line width is measured in the region of the patterned metal film, and the overetching rate is calculated.

  There is a limit to reducing the line width of the patterned resist film formed on the metal film in the resist film forming step (A), and therefore, in the method of etching to the same extent as the line width of the patterned resist film, It is difficult to form a high-definition patterned metal film having a smaller line width. Therefore, in order to obtain a patterned metal film having a small line width, a method of obtaining a high-definition patterned metal film having a smaller line width by over-etching is important.

  In particular, when a patterned resist film is formed by a printing method in the resist film forming step (A), it is difficult to obtain a patterned resist film having a smaller line width compared to the photolithography method, and as described above, overetching is necessary. The sex becomes even greater.

  Further, when forming a patterned resist film by a printing method, it is preferable to reduce the thickness of the patterned resist film in order to form a pattern having a smaller line width. From this viewpoint, it is preferable that the thickness of the resist film is small. Further, reducing the thickness of the resist film is used for reducing the raw material cost, shortening the resist film curing process and resist film peeling process, which will be described later, and the resist film peeling process. There are advantages such as being able to suppress degradation of the stripping solution (alkaline aqueous solution).

  Therefore, in the present invention, it is important that the thickness of the patterned resist film formed on the metal film in the resist film forming step (A) is 5 μm or less.

  However, if the thickness of the patterned resist film is 5 μm or less and overetching is performed until the overetching rate is 80% or less, the patterned resist film 2 is partially broken in the etching step (B) as shown in FIG. A new problem has arisen.

  FIG. 4 is a schematic plan view showing the relationship between the patterned resist film and the metal film during overetching. As over-etching progresses, the line width (indicated by dotted lines) of the metal film 1 becomes smaller than the line width of the patterned resist film 2, but in this process, the patterned resist film 2 is partially broken and chipped. The problem occurs. When the patterned resist film 2 is partially chipped, etching proceeds from the chipped portion, and the line width of the metal film 1 becomes too small or is disconnected to produce a metal film having a desired pattern. become unable.

  The above problem is solved by using a patterned resist film having a pencil hardness of B or less. The pencil hardness of the patterned resist film used in the present invention is preferably 2B or less, and more preferably 3B or less. The lower limit is about 6B.

  In the present invention, the overetching rate (ratio (%) of the line width of the patterned metal film to the line width of 100% of the patterned resist film) is preferably 75% or less, more preferably 70% or less, and particularly preferably 65% or less. Is preferred. The lower limit is preferably 30% or more.

  In order to make the line width of the patterned metal film 80% or less with respect to the line width of 100% of the patterned resist film, the etching conditions (such as the temperature of the etching solution and the processing time with the etching solution) are adjusted. Is possible.

  The relationship between the over-etching rate and the pencil hardness of the patterned resist film is such that the smaller the over-etching rate (the smaller the ratio (%) of the line width of the patterned metal film to 100% of the line width of the patterned resist film), It is preferable to lower the pencil hardness of the patterned resist film. Specifically, when the overetching rate is 70% or less, the pencil hardness of the patterned resist film is preferably 2B or less, and when the overetching rate is 60% or less, the pencil hardness of the patterned resist film is 3B. The following is preferable.

  In general, the patterned resist film does not have an area necessary for measuring the pencil hardness, so it is difficult to measure the pencil hardness of the patterned resist film. Therefore, in the present invention, the pencil hardness of the patterned resist film is measured by preparing a sample for pencil hardness measurement separately and substituting the pencil hardness value obtained from the sample. The pencil hardness measurement sample is formed by forming a continuous film of a resist film (for example, a width of 5 cm or more and a length of 5 cm or more) on a polyethylene terephthalate film (PET film) having a thickness of 100 μm and curing under a predetermined curing condition. To make.

  Here, the predetermined thickness means the same thickness as the actual thickness of the patterned resist film. Similarly, the predetermined curing conditions mean the same conditions as the curing conditions used in the actual production of the patterned resist film. Specifically, the curing conditions are a heating temperature and a heating time in the case of a thermosetting resist composition, and an irradiation amount of active energy rays (for example, an ultraviolet curable type resist composition in the case of an active energy ray curable resist composition). In this case, the integrated light quantity of ultraviolet rays).

The resist film according to the present invention is preferably a film obtained by curing a thermosetting or active energy ray curable resist film forming composition (hereinafter simply referred to as a resist composition), and in particular, active energy ray curing. The film is preferably a film obtained by curing the type resist composition.
Hereinafter, the active energy ray-curable resist composition preferably used in the present invention will be described.

  The active energy ray-curable resist composition comprises a monomer and / or oligomer (hereinafter referred to as component a) having one or more ethylenically unsaturated groups and one or more ethyleneoxy groups in one molecule, and It is preferable that at least one resin having at least one carboxyl group and having an acid value of 50 or more and less than 200 (hereinafter referred to as component b) in one molecule.

  The pencil hardness of the resist film is adjusted by adjusting, for example, the mixing ratio of component a and component b in the active energy ray-curable resist composition, or the type of component a (the number of ethylenically unsaturated groups, etc.). It is possible by adjusting

  The number of ethylenically unsaturated groups contained in component a is preferably 2 to 10, more preferably 2 to 6, and particularly preferably 2 to 4. The number of ethyleneoxy groups contained in component a is preferably 2 to 12, more preferably 3 to 10, and particularly preferably 4 to 8.

  That is, a compound preferable as component a is a compound having 2 to 10 ethylenically unsaturated groups and 2 to 12 ethyleneoxy groups in one molecule, and a more preferable compound as component a is in one molecule. The number of ethylenically unsaturated groups is 2 to 6 and 3 to 10 ethyleneoxy groups, and a particularly preferred compound as component a is that the number of ethylenically unsaturated groups is 2 in one molecule. It is a compound having -4 and 4-8 ethyleneoxy groups.

  As said ethylenically unsaturated group, (meth) acryl group, a vinyl group, an allyl group etc. are mentioned, for example.

  The number average molecular weight of component a is preferably 2000 or less, more preferably 1500 or less, and particularly preferably 1000 or less.

  Preferred compounds (monomers, oligomers) of component a include, for example, polyethylene glycol di (meth) acrylate, poly (ethylene glycol-propylene glycol) di (meth) acrylate, poly (ethylene glycol-tetramethylene glycol) di (meth) acrylate. , EO-modified trimethylolpropane tri (meth) acrylate, EO-PO-modified trimethylolpropane tri (meth) acrylate, EO-modified pentaerythritol tri (meth) acrylate, EO-PO-modified pentaerythritol tri (meth) acrylate, EO-modified penta Erythritol hexa (meth) acrylate, EO-PO modified pentaerythritol hexa (meth) acrylate, EO modified dipentaerythritol penta (meth) acrylate, E -PO modified dipentaerythritol penta (meth) acrylate, EO modified dipentaerythritol hexa (meth) acrylate, EO-PO modified dipentaerythritol hexa (meth) acrylate, EO modified bisphenol A di (meth) acrylate, EO-PO modified Examples thereof include bisphenol A di (meth) acrylate.

  In the above exemplary compounds, EO represents an ethyleneoxy group and PO represents a propyleneoxy group.

  When the resist composition contains the component a, the pencil hardness can be lowered as compared with the conventional resist film, and a resist film having a pencil hardness of B or less can be formed.

  In addition, since the resist composition contains the component a, the resist film can be easily peeled off due to swelling of the resist film in the step of peeling the resist film with an alkaline aqueous solution, which will be described later. Is suppressed, and deterioration of the aqueous alkali solution and reprecipitation of the resist film component can be suppressed.

  As described above, the resist composition preferably contains the component b. The component b is a resin having one or more carboxyl groups in one molecule and an acid value of 50 or more and less than 200. Further, as the component b, a resin having an acid value of 70 or more and less than 150 is preferable. The acid value can be measured by a measurement method defined in JISK2501 (2003).

  As the component b, a resin satisfying the above conditions can be used from among resins known as alkali-soluble resins. Examples of component b include acrylic resin, styrene-acrylic resin, maleic resin, and styrene-maleic resin.

  By including the component b in the resist composition, the releasability of the resist film is improved in the resist film peeling step with an alkaline aqueous solution, which will be described later, and an increase in the elution concentration of the resist film component in the alkaline aqueous solution is suppressed. .

  The content of the component a in the resist composition is 20% by mass with respect to 100% by mass of the total solid content of the resist composition from the viewpoint of ensuring etching resistance while adjusting the pencil hardness of the resist film to B or less. The above is preferable, 25 mass% or more is more preferable, and 30 mass% or more is particularly preferable. Further, from the viewpoint of ensuring good releasability in the resist film peeling step, the upper limit of the content of component a is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

  The content of the component b in the resist composition is preferably 30% by mass or more with respect to 100% by mass of the total solid content of the resist composition from the viewpoint of ensuring good releasability in the resist film peeling step. It is preferably at least 40% by mass, particularly preferably at least 40% by mass. In addition, from the viewpoint of ensuring etching resistance, the upper limit of the content of component b is preferably 75% by mass or less, more preferably 65% by mass or less, and particularly preferably 55% by mass or less.

  The above-mentioned etching resistance refers to the erosion resistance of the resist film by the etching solution in the etching step (B). When the etching resistance of the resist film deteriorates, a pinhole or the like is generated in the resist film, and the pin Dissolution of the metal film spreads from the hole, causing a disadvantage that a portion that is not an original etching portion is dissolved.

  The resist composition can contain monomers and / or oligomers other than component a in order to adjust the film strength (strength of the resist film). Examples of the monomer used suitably other than the component a include, for example, ethylene glycol di (meth) acrylate, bisphenol A di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipenta Erythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethanetri (meth) Acrylate, 1,2,4-cyclohexanetetra (meth) acrylate, pentaglycerol triacrylate, tripentaerythritol triacrylate, tripe Such data hexa triacrylate and the like, also, urethane (meth) acrylates, polyester (meth) acrylates, may also be used multifunctional monomer or multifunctional oligomer, such as epoxy (meth) acrylates.

  The content of the monomer and / or oligomer other than the component a described above is preferably adjusted in a range of 50 parts by mass or less, more preferably in a range of 40 parts by mass or less, with respect to 100 parts by mass of the component a. Furthermore, it is preferable to adjust in the range of 30 mass parts or less, and it is preferable to adjust in the range of 20 mass parts or less especially.

  The resist composition preferably further contains a thixotropic agent. Here, the thixotropic agent is a substance for causing the resist composition to exhibit thixotropic properties. The thixotropic property refers to a phenomenon in which the fluid viscosity decreases due to an increase in stirring, vibration, shear rate, and the like. Details are described in the book “The World of Rheology” (written by Kunihiro Ozaki, Industrial Research Society (issued in 2004), p114).

  By imparting appropriate thixotropy to the resist composition of the present invention, fluidity and spinnability are improved, and as a result, a high-definition pattern can be printed.

  Examples of such thixotropic imparting agents include organic thixotropic imparting agents such as fatty acid amide waxes, oxidized polyolefin waxes, and acrylic waxes, silica fine particles, carbon black, bentonite, talc, clay, calcium carbonate, and barium sulfate. System thixotropic imparting agents.

  The content of the thixotropic imparting agent is suitably in the range of 1 to 20% by mass and preferably in the range of 2 to 15% by mass with respect to 100% by mass of the total solid content of the resist composition.

  The resist composition can further contain a colorant. Examples of the colorant include pigments and dyes such as carbon black, phthalocyanine green, phthalocyanine blue, crystal violet, malachite green, Victoria blue, and methyl violet. These may be used alone or in combination.

  It is preferable that the resist composition further contains a photopolymerization initiator. Examples of such photopolymerization initiator include acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, benzophenone, 2-chlorobenzophenone, 4,4′-dichlorobenzophenone, 4, 4′-bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, methyl benzoylformate, p-isopropyl-α-hydroxyisobutylphenone, α-hydroxyisobutylphenone, 2,2- Carbonyl compounds such as dimethoxy-2-phenylacetophenone and 1-hydroxycyclohexyl phenyl ketone, tetramethylthiuram monosulfide, tetramethyl Examples thereof include sulfur compounds such as ruthiuram disulfide, thioxanthone, 2-chlorothioxanthone, and 2-methylthioxanthone. These photopolymerization initiators may be used alone or in combination of two or more. .

  The content of the photopolymerization initiator is suitably in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the component a.

  The resist composition preferably contains an organic solvent in order to adjust the viscosity to be suitable for printing. Examples of the organic solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol mono-t-butyl ether, ethylene Glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol monobutyl ether, ethers such as triethylene glycol dimethyl ether, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propyl acetate, butyl acetate, isobutyl acetate, 3-methoxybutyl acetate Acetates such as 3-methyl-3-methoxybutyl acetate, methyl lactate, ethyl lactate, butyl lactate, acetylacetone, methylpropylketone, methylbutylketone, methylisobutylketone, cyclopentanone, cyclohexanone, 2-heptanone, etc. Alcohols such as ketones, butanol, isobutyl alcohol, pentanol, 4-methyl-2-pentanol, 3-methyl-2-butanol, 3-methyl-3-methoxy-1-butanol, diacetone alcohol, benzyl alcohol And aromatic hydrocarbons such as toluene and xylene, and these organic solvents can be used alone or in combination.

  The content of the organic solvent is suitably in the range of 5 to 50% by mass, preferably in the range of 10 to 40% by mass, and more preferably in the range of 15 to 35% by mass with respect to 100% by mass of the resist composition. preferable.

  The method for producing the resist composition is not particularly limited. Specifically, the resist composition is produced by combining the above-described component a and component b in combination with a ball mill, bead mill, roll mill, disper, kneader, mixer, or the like. be able to.

  When the printing method is used in the resist film forming step (A), the viscosity of the resist composition (viscosity at 25 ° C.) is preferably in the range of 0.03 to 30 Pa · s at a shear rate of 100 (1 / s). A range of 0.1 to 10 Pa · s is more preferable, and a range of 1 to 10 Pa · s is particularly preferable.

  When a printing method is used in the resist film forming step (A), the resist composition is printed in a predetermined pattern on the metal film, and then irradiated with active energy rays and cured to form a patterned resist film.

  Further, as described above, when the resist composition contains an organic solvent, it is preferable to heat and dry the resist composition after printing it on the metal film and before irradiating the active energy rays.

  Examples of the active energy rays irradiated to cure the resist composition printed on the metal film include ultraviolet rays, electron beams and radiation (α rays, β rays, γ rays, etc.), and practically. Ultraviolet rays are simple and preferable. As the ultraviolet ray source, an ultraviolet fluorescent lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a xenon lamp, a carbon arc lamp, or the like can be used. Moreover, when irradiating an active energy ray, if it irradiates under low oxygen concentration, it can harden | cure efficiently. Furthermore, the electron beam system is expensive and requires operation under an inert gas, but it does not have to contain a photopolymerization initiator or photosensitizer in the printed resist composition. This is advantageous.

  In the present invention, the method of curing the resist composition is preferably a method of curing by irradiating ultraviolet rays because high productivity can be obtained with a relatively simple apparatus.

  As described above, the thickness of the patterned resist film formed on the metal film in the resist film forming step (A) is important to be 5 μm or less, preferably 4 μm or less, more preferably 3 μm or less. In particular, 2 μm or less is preferable. The lower limit of the thickness of the patterned resist film is preferably 0.5 μm or more, and more preferably 1 μm or more. Here, the thickness of the patterned resist film is the maximum thickness in the width direction of the lines constituting the pattern.

  If the thickness of the patterned resist film is less than 0.5 μm, the problem of partial breakage of the patterned resist film during overetching may not be sufficiently solved.

  When the thickness of the patterned resist film exceeds 5 μm, in addition to the above-described problem, there is a problem that the processing load of the pattern resist film peeling process with an alkaline aqueous solution described later increases.

  After the metal film is etched and the patterned metal film is formed in the etching step (B), the patterned resist film is preferably peeled and removed. In such a resist film peeling and removing process, the resist film is usually peeled and removed using an alkaline aqueous solution.

  Examples of the alkaline aqueous solution used in the patterned resist film peeling and removing step include 1 to 5% by mass of a sodium hydroxide aqueous solution and a potassium hydroxide aqueous solution. The temperature of the alkaline aqueous solution is suitably in the range of 20 to 60 ° C, and preferably in the range of 30 to 55 ° C. The treatment time with the aqueous alkali solution is suitably in the range of 5 to 100 seconds, and preferably in the range of 20 to 80 seconds.

  As described above, the patterned metal film is preferably used in a state of being laminated on a suitable base material such as a glass plate, a plastic plate, or a plastic film. Among the substrates, a plastic film is preferably used from the viewpoint of continuously forming a pattern in a roll-to-roll manner in the resist film forming step (A).

  Examples of the resin constituting the plastic film include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, cellulose resins such as triacetyl cellulose, polyolefin resins such as polyethylene, polypropylene, and polybutylene, acrylic resins, polycarbonate resins, cyclic olefin resins, and epoxy. Examples include resins, polyimide resins, polyetherimide resins, polyamide resins, polysulfone resins, polyphenylene sulfide resins, and polyether sulfone resins.

  The thickness of the plastic film is suitably in the range of 20 to 300 μm, but is preferably in the range of 50 to 250 μm from the viewpoint of cost handling.

  The plastic film is preferably a plastic film in which an easy-adhesion layer for strengthening adhesion (adhesion strength) with a metal film or a patterned metal film is laminated in advance. That is, it is preferable to use a plastic film having an easy-adhesion layer as the substrate.

  As such an easy-adhesion layer, those using a water-soluble resin or a water-dispersible resin are generally known and are also preferably used in the present invention. As the water-soluble resin or water-dispersible resin, polyurethane resin, polyester resin, acrylic resin, polyvinyl alcohol resin, or the like is used. The easy-adhesion layer preferably further contains a crosslinking agent. Examples of the crosslinking agent include isocyanate compounds, epoxy compounds, oxazoline compounds, melamine compounds, and the like. Further, it is preferable that the easy adhesion layer further contains inorganic fine particles (for example, silica fine particles).

  The thickness of the easy-adhesion layer is suitably in the range of 5 to 500 nm, preferably in the range of 10 to 300 nm, and more preferably in the range of 20 to 200 nm. The easy-adhesion layer may be formed after the plastic film is manufactured, or may be formed in-line when the plastic film is manufactured.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these Examples. In addition, the measuring method and evaluation method in a present Example are as follows.
(1) Measurement of pencil hardness of patterned resist film On a PET film having a thickness of 100 μm, the resist composition was applied so that the thickness after drying / curing (thickness of the resist film) was 1.5 μm. A resist film is formed by drying with hot air and curing by irradiating ultraviolet rays from a high-pressure mercury UV lamp with an integrated light amount of 200 mJ / cm ² . The pencil hardness of the resist film is measured in accordance with JIS K 5600-5-4 (1999) except that a PET film having a thickness of 100 μm is used as a base material. The pencil hardness value thus obtained was taken as the pencil hardness value of the patterned resist film.
(2) Measurement of thickness of patterned resist film A sample cross section was cut out with a microtome, and the cross section was observed with an electrolytic emission scanning electron microscope (Hitachi S-800, acceleration voltage 26 kV, observation magnification 3000 times). Then, the thickness of the maximum part of the patterned resist film was measured. That is, the sample size is 20 cm × 20 cm, the maximum thickness in each width direction is measured at any five locations, and the average value is taken as the thickness of the patterned resist film.
(3) Measurement of the line width of the patterned resist film The sample in which the patterned resist film is formed on the metal film in the resist forming step (A) is used with a digital microscope (for example, VHX-200 manufactured by Keyence). The surface is observed at a magnification of 450 times, and the line width is measured using the length measurement function. The sample size is 20 cm × 20 cm and is measured at any five locations, and the average value is taken as the line width of the resist film.
(4) Measurement of line width of patterned metal film Magnification of the patterned metal film obtained through the etching step (B) and the resist film peeling step using a digital microscope (for example, VHX-200 manufactured by Keyence) The surface is observed at 450 times, and the line width is measured using the length measurement function. The sample size is 20 cm × 20 cm and is measured at any five locations, and the average value is taken as the line width of the metal film.
(5) Over-etching rate From the line widths of the patterned resist film and the patterned metal film obtained in the above (3) and (4), the over-etching rate (of the patterned metal film with respect to 100% of the line width of the patterned resist film) The line width ratio (%) was calculated.
(6) Evaluation of patterned metal film The obtained patterned metal film was observed and evaluated according to the following criteria.

  A: No partial chipping or disconnection is observed in the thin line.

  ○: There is a slight chip in the thin line, but there is no practical problem.

X: The fine line is partially largely missing or the fine line is broken.
(Example 1, Example 2)
A patterned metal film was produced in the following manner.

<Manufacture of metal film>
On one side of a 100 μm thick PET film (Lumirror (registered trademark) U426 manufactured by Toray Industries, Inc.) having an easy adhesion layer on both sides, a nickel sputtered film (thickness 0.02 μm) and a copper vacuum deposited film (thickness) 1.5 μm) were laminated in this order.

<Resist film forming step (A)>
The following resist composition was printed on the surface of the metal film produced above in a lattice pattern by a direct gravure printing method. Next, it was dried by hot air at 60 ° C., and was cured by irradiating with ultraviolet light from a high-pressure mercury UV lamp at an integrated light quantity of 200 mJ / cm ² to form a patterned resist film. The lattice pattern resist film had a thickness of 1.5 μm and a line width of 50 μm.

<Resist composition>
As component b, 34.4 parts by mass of ARUFON-UC-3000 (acrylic resin, acid value 74) manufactured by Toagosei Co., Ltd. was weighed and dissolved in 21 parts by mass of triethylene glycol dimethyl ether. Thereto, 5 parts by mass of carbon black # 40 manufactured by Mitsubishi Chemical Corporation was added as a colorant and mixed in a three-roll mill. Next, as component a, A-BPE-4 (EO-modified acrylic monomer; bifunctional monomer having 4 EO number) manufactured by Shin-Nakamura Chemical Co., Ltd. and Light Acrylate TMP manufactured by Kyoeisha Chemical Co., Ltd. -6EO-3A (EO-modified acrylic monomer; trifunctional monomer having 6 EO) 13.8 parts by mass was added and mixed and stirred. Furthermore, 7 parts by mass of Disparon DFA-220 manufactured by Enomoto Kasei Co., Ltd. as a thixotropic agent and 5 parts by mass of Irgacure 184 manufactured by Ciba Specialty Chemicals Co., Ltd. as a photopolymerization initiator were added and mixed and stirred.

<Etching step (B)>
A portion of the metal film not covered with the resist film was etched with an etching solution (ferric chloride aqueous solution (42 ° Be)) adjusted to a temperature range of 30 to 33 ° C. to form a patterned metal film.

  Sample (implementation) in which the etching time is adjusted in the etching step (B), and the over-etching rate (ratio of the line width of the patterned metal film to the line width of 100% of the patterned resist film (%)) is 50% Example 1) and a sample of 70% (Example 2) were prepared.

<Resist film peeling process>
The resist film on the patterned metal film was stripped for 30 seconds with a 2% by mass aqueous sodium hydroxide solution adjusted to a temperature range of 50 ° C.
(Example 3, Example 4)
A sample in which the over-etching rate is 50% (Example 3) and a sample in which 70% are obtained in the same manner as in Examples 1 and 2 except that the resist composition in Example 1 is changed to the following resist composition. (Example 4) was produced.

<Resist composition>
32 parts by mass of ARUFON-UC-3000 (acrylic resin, acid value 74) manufactured by Toagosei Co., Ltd. was weighed out as component b and dissolved in 21 parts by mass of triethylene glycol dimethyl ether. Thereto, 5 parts by mass of carbon black # 40 manufactured by Mitsubishi Chemical Corporation was added as a colorant and mixed in a three-roll mill. Next, as component a, 15 parts by mass of Shin-Nakamura Chemical Co., Ltd. A-BPE-4 (EO-modified acrylic monomer; bifunctional monomer having 4 EO) and Kyoeisha Chemical Co., Ltd. Light Acrylate TMP-6EO 15 parts by mass of -3A (EO-modified acrylic monomer; trifunctional monomer having 6 EO) was added and mixed and stirred. Furthermore, 7 parts by mass of Disparon DFA-220 manufactured by Enomoto Kasei Co., Ltd. as a thixotropic agent and 5 parts by mass of Irgacure 184 manufactured by Ciba Specialty Chemicals Co., Ltd. as a photopolymerization initiator were added and mixed and stirred.
(Example 5, Example 6)
A sample with an overetching rate of 50% (Example 5) and a sample with 70%, in the same manner as in Examples 1 and 2, except that the resist composition of Example 1 was changed to the following resist composition. (Example 6) was produced.

<Resist composition>
As component b, 34.4 parts by mass of ARUFON-UC-3000 (acrylic resin, acid value 74) manufactured by Toagosei Co., Ltd. was weighed and dissolved in 21 parts by mass of triethylene glycol dimethyl ether. Thereto, 5 parts by mass of carbon black # 40 manufactured by Mitsubishi Chemical Corporation was added as a colorant and mixed in a three-roll mill. Next, as component a, 17.6 parts by mass of A-BPE-4 (EO-modified acrylic monomer; bifunctional monomer having 4 EOs) manufactured by Shin-Nakamura Chemical Co., Ltd. and 10 parts by mass of dipentaerythritol hexaacrylate And mixed and stirred. Furthermore, 7 parts by mass of Disparon DFA-220 manufactured by Enomoto Kasei Co., Ltd. as a thixotropic agent and 5 parts by mass of Irgacure 184 manufactured by Ciba Specialty Chemicals Co., Ltd. as a photopolymerization initiator were added and mixed and stirred.
(Comparative Example 1)
A patterned metal film was produced in the same manner as in Examples 1 and 2 except that the resist composition of Example 1 was changed to the following resist composition.
However, in the etching step (B), a sample in which the over etching rate (ratio of the metal film line width to the resist film line width of 100% (%)) is 70% by adjusting the etching time (Comparative Example 1). , And 90% of the sample (Comparative Example 2).

<Resist composition>
As component b, 34.4 parts by mass of ARUFON-UC-3000 (acrylic resin, acid value 74) manufactured by Toagosei Co., Ltd. was weighed and dissolved in 21 parts by mass of triethylene glycol dimethyl ether. Thereto, 5 parts by mass of carbon black # 40 manufactured by Mitsubishi Chemical Corporation was added as a colorant and mixed in a three-roll mill. Next, A-BPE-4 (EO-modified acrylic monomer; bifunctional monomer having 4 EO number) manufactured by Shin-Nakamura Chemical Co., Ltd. as component a, 13.8 parts by mass, and dipentaerythritol hexaacrylate 13.8 A part by mass was added and mixed and stirred. Furthermore, 7 parts by mass of Disparon PFA-220 manufactured by Enomoto Kasei Co., Ltd. as a thixotropic agent and 5 parts by mass of Irgacure 184 manufactured by Ciba Specialty Chemicals Co., Ltd. as a photopolymerization initiator were added and mixed and stirred.
(Comparative Examples 2 to 4)
A patterned metal film was produced in the same manner as in Examples 1 and 2, except that the resist composition of Example 1 was changed to “Etching Resist ER-112N” manufactured by Toyobo Co., Ltd.
However, in the etching step (B), a sample in which the etching time is adjusted and the over-etching ratio (ratio of the metal film line width to the resist film line width of 100% (%)) is 70% (Comparative Example 3). , And 90% of the sample (Comparative Example 4).
<Evaluation>
Table 1 shows the results of measurements and evaluations on the above Examples and Comparative Examples.

  From the results of Table 1, in the examples of the present invention, even when the thickness of the resist film is 5 μm or less and the overetching rate is 80% or less, the resist film is not partially broken, and a metal film having a desired pattern is obtained. I understand that

  On the other hand, in the comparative example, when the thickness of the resist film is 5 μm or less and the overetching rate is 80% or less, the resist film is partially broken and chipped, and as a result, the fine line of the patterned metal film is partially large. It was missing or the fine wire was broken.

1 Metal film 2 Resist film 3 Base material

Claims (6)

A method for producing a patterned metal film, which includes a step (A) of forming a patterned resist film on the metal film and a step (B) of etching the metal film,
The resist film has a thickness of 0.5 μm or more and 5 μm or less and a pencil hardness of B or less,
In the step (B), the patterned metal film is overetched by chemical etching so that the line width of the patterned metal film is 80% or less with respect to 100% of the line width of the resist film.   The method for producing a patterned metal film according to claim 1, wherein the step (A) forms a patterned resist film on the metal film by a printing method.   The method for producing a patterned metal film according to claim 2, wherein the printing method is a gravure printing method.   The method for producing a patterned metal film according to any one of claims 1 to 3, wherein the resist film is obtained by curing an active energy ray-curable resist film forming composition. The method for producing a patterned metal film according to claim 4, wherein the composition for forming an active energy ray-curable resist film includes at least the following component a and the following component b.
Component a: Monomer and / or oligomer having one or more ethylenically unsaturated groups and one or more ethyleneoxy groups in one molecule Component b; having one or more carboxyl groups in one molecule And an acid value of 50 or more and less than 200   The manufacturing method of the patterned metal film in any one of Claims 1-5 which has the process of peeling and removing the said resist film further after the said process (B).

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