Electronic circuit board

Abstract

To provide an electronic circuit board that achieves both excellent resolution and concealment while also being suitable for optical defect inspection.SOLUTION: In an electronic circuit board comprising a substrate, a wiring pattern, and a cured layer obtained by curing a photosensitive resin composition, the cured layer constitutes a portion of the surface of the electronic circuit board, and the cured layer has predetermined optical properties.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an electronic circuit board. [Background technology]

[0002] As wiring patterns on electronic circuit boards become increasingly finer, it is becoming more difficult to visually inspect the occurrence of defects in electronic circuit boards. Therefore, in order to manufacture high-density electronic circuit boards with a high yield and guarantee their quality, it is necessary to automate the inspection of wiring patterns and be able to detect the occurrence of defects.

[0003] Known methods for inspecting defects in wiring patterns on electronic circuit boards include irradiating the board with infrared light, visible light, ultraviolet light, X-rays, etc., and detecting the image of the pattern from the reflected light, transmitted light, etc., optically visualizing the wiring pattern and insulating layer patterns, etc., and detecting them as binary images for comparison inspection.

[0004] For example, Patent Document 1 discloses an inspection method for wiring circuit boards that can determine the quality of a wiring pattern with high accuracy, in which, during inspection of the wiring circuit board, a first wiring board is irradiated with a first light having a peak wavelength in a wavelength range of 425 nm or more and 525 nm or less, an image is generated based on the reflected light, and a second wiring board is irradiated with a second light having a peak wavelength in a wavelength range of 630 nm or more and 850 nm or less, an image is generated based on the reflected light, and the quality of the wiring pattern is determined based on these generated images. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-186557 Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the above circumstances, an object of the present invention is to provide an electronic circuit board that achieves both good resolution and concealment and is suitable for optical defect inspection. [Means for solving the problem]

[0007] As a result of extensive research into achieving the above object, the present inventors have discovered that an electronic circuit board suitable for optical defect inspection while maintaining good resolution and concealment can be obtained by providing an electronic circuit board having a substrate, a wiring pattern, and a cured material layer obtained by curing a photosensitive resin composition, wherein the cured material layer constitutes a part of the surface of the electronic circuit board, and the cured material layer has (a) a transmittance of 1% or more at a wavelength of 365 nm, (b) a transmittance of 13% or more at a wavelength of 405 nm, (c) a transmittance of 24% or less at a wavelength of 450 to 500 nm, (d) a maximum transmittance of 13% or more and 24% or less in the wavelength region of 500 to 550 nm, (e) a transmittance of 24% or less at a wavelength of 550 to 725 nm, and (f) a transmittance of 13% or more at a wavelength of 750 to 850 nm, thereby completing the present invention.

[0008] In the electronic circuit board according to the embodiment of the present invention, the L of the cured material layer constituting a part of the surface of the electronic circuit board * Preferably, the L value of the cured material layer is 26 or less. The cured material layer is obtained by curing a photosensitive resin composition, and the cured material layer has a transmittance of 24% or less at wavelengths of 450 to 500 nm and a transmittance of 24% or less at wavelengths of 550 to 725 nm. In addition, the L value of the cured material layer is * A cured material layer having excellent hiding properties can be obtained by setting the value to 26 or less. Furthermore, a cured material layer having a maximum transmittance of 13% or more and 24% or less in the wavelength region of 500 to 550 nm can be obtained while maintaining hiding properties and being suitable for optical defect inspection.

[0009] In addition, the electronic circuit board according to this embodiment of the present invention may have a portion in which the line / space of the cured material layer is 100 μm / 100 μm or less, and may have via holes with an opening diameter of 100 μm or less. In the electronic circuit board, the photosensitive resin composition that provides the cured material layer satisfies the optical properties (a) and (b), i.e., has a certain degree of transmittance in the wavelength ranges of 365 nm and 405 nm, so that resolution can be ensured.

[0010] Furthermore, in the electronic circuit board according to the present invention, the cured product layer may be formed on a substrate or a wiring pattern having a copper residual ratio of 60% or more, or on the substrate and the wiring pattern. When the photosensitive resin composition is cured on copper, the bottom part is more easily cured due to the light reflected from the copper, and good resolution can be achieved.

[0011] In an electronic circuit board according to another embodiment of the present invention, the photosensitive resin composition that forms the cured layer can be a photosensitive resin composition containing (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a photopolymerizable monomer, (D) an epoxy resin, and (E) an organic pigment. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide an electronic circuit board that has both good resolution and concealment properties and is also suitable for optical defect inspection. DETAILED DESCRIPTION OF THE INVENTION

[0013] Preferred embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments.

[0014] In this specification, "(meth)acrylate" is a term that collectively refers to "acrylate," "methacrylate," and mixtures thereof, and the same applies to other similar expressions.

[0015] [1. Electronic circuit board] The electronic circuit board according to this embodiment has a substrate, a wiring pattern, and a cured layer obtained by curing a photosensitive resin composition.

[0016] [1-1. Substrate and wiring pattern] The substrate used in this embodiment is not particularly limited, and examples thereof include printed wiring boards and flexible printed wiring boards having a wiring pattern in which a circuit is formed in advance using copper or the like, as well as copper-clad laminates for high-frequency circuits made of materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, fluororesin / polyethylene / polyphenylene ether, polyphenylene oxide / cyanate, and the like, and copper-clad laminates of all grades (FR-4, etc.), as well as metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer plates, etc.

[0017] The copper remaining ratio of the substrate or wiring pattern is preferably 60% or more, more preferably 70% or more. When the photosensitive resin composition is cured on copper, the bottom part is more easily cured due to the light reflected from the copper, and good resolution can be achieved.

[0018] [1-2. Cured material layer] The cured layer according to this embodiment is obtained by curing a photosensitive resin composition and constitutes a part of the surface of an electronic circuit board. The cured layer has the following optical properties (a) to (f): (a) Transmittance of 1% or more at a wavelength of 365 nm (b) Transmittance of 13% or more at a wavelength of 405 nm (c) Transmittance at wavelengths of 450 to 500 nm is 24% or less (d) The maximum transmittance in the wavelength range of 500 to 550 nm is 13% or more and 24% or less. (e) Transmittance at wavelengths of 550 to 725 nm is 24% or less (f) Transmittance at wavelengths of 750 to 850 nm is 13% or more

[0019] Furthermore, the L of the cured material layer * From the viewpoint of ensuring hiding power, the value is preferably 26 or less, more preferably 24 or less, and even more preferably 20 or less. where L * The value is L * a * b * It is an index that represents the lightness (brightness) in the color space of the color system, and the lower the value, the darker the color tone. * The value can be measured in accordance with JIS Z 8781 using a spectrophotometer (for example, CM-2600d (manufactured by Konica Minolta Japan, Inc.)).

[0020] The cured material layer according to this embodiment uses a photosensitive resin composition having the optical properties (a) and (b) described above, thereby achieving good resolution. Therefore, it is possible to form a cured material layer portion having a line / space (L / S) of 100 μm / 100 μm or less (wiring pitch of 200 μm or less). The line / space of the cured material layer is not particularly limited, and may have a portion of 150 μm / 150 μm or less, a portion of 100 μm / 100 μm or less, or a portion of 80 μm / 80 μm or less.

[0021] Similarly, since the cured material layer according to this embodiment uses the photosensitive resin composition, the opening diameter of the via hole can be 100 μm or less. The opening diameter of the via hole in the cured material layer is not particularly limited and may be 200 μm or less, 150 μm or less, or 100 μm or less. The lower limit of the opening diameter of the via hole is also not particularly limited and may be 1 μm or more, or 10 μm or more.

[0022] <Method of manufacturing the cured material layer> When the cured product layer of this embodiment is produced using a photosensitive resin composition, it can be produced by applying the photosensitive resin composition to a substrate, drying it to produce a resin layer, exposing the resin layer to active energy rays, and developing it. When the cured product layer is produced using a dry film having a photosensitive resin composition as a resin layer, it can be produced by laminating the resin layer of the dry film on a substrate, exposing the resin layer to active energy rays, and developing it. The method for producing a dry film having the photosensitive resin composition as a resin layer will be described later.

[0023] <Coating, drying and laminating process> The photosensitive resin composition may be adjusted to a viscosity suitable for the coating method using an organic solvent, coated onto a substrate by a method such as dip coating, flow coating, roll coating, bar coating, screen printing, or curtain coating, and then the organic solvent contained in the composition is evaporated and dried (pre-dried) at a temperature of 60 to 100° C. Alternatively, in the case of a dry film, the resin layer can be formed on the substrate by laminating it onto the substrate using a laminator or the like so that the resin layer is in contact with the substrate.

[0024] The dry film is preferably applied to the substrate under pressure and heat using a vacuum laminator or the like. By using such a vacuum laminator, even if a circuit-formed substrate is used, the dry film adheres tightly to the circuit substrate, preventing the inclusion of air bubbles and improving the filling of recesses in the substrate surface. The pressure is preferably about 0.1 to 2.0 MPa, and the heating temperature is preferably 40 to 120°C.

[0025] The volatilization drying carried out after coating the photosensitive resin composition can be carried out using a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, or the like (a method in which hot air in a dryer equipped with a heat source of an air heating method using steam is brought into countercurrent contact with the substrate, or a method in which hot air is blown onto the substrate from a nozzle).

[0026] <Exposure and development process> After forming a resin layer on a substrate, it is selectively exposed to active energy rays through a photomask with a predetermined pattern, and the unexposed areas are developed with a dilute alkaline aqueous solution (e.g., a 0.3 to 3% by mass sodium carbonate aqueous solution) to form a patterned cured layer. In the case of a dry film, after exposure, the first film is peeled off from the dry film and development is carried out, thereby forming a patterned cured layer on the substrate. Note that, as long as the properties are not impaired, the first film may be peeled off from the dry film before exposure, and the exposed resin layer may be exposed and developed.

[0027] Furthermore, by irradiating the cured material layer with active energy rays and then heat-curing (for example, at 100 to 220°C), or by irradiating active energy rays after heat-curing, or by heat-curing alone to perform final finish curing (main curing), a cured material layer with excellent properties such as adhesion and hardness can be formed.

[0028] The exposure device used for the above-mentioned active energy ray irradiation may be a device equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, or the like, and capable of irradiating ultraviolet rays in the range of 350 to 450 nm. Furthermore, a direct imaging device (for example, a laser direct imaging device that directly draws an image with a laser based on CAD data from a computer) may also be used. The lamp or laser light source of the direct imaging device may have a maximum wavelength in the range of 350 to 450 nm. The exposure dose for image formation varies depending on factors such as the film thickness, but is generally 10 to 1,000 mJ / cm. 2 , preferably 20 to 800 mJ / cm 2 The range may be:

[0029] The developing method may be a dipping method, a shower method, a spray method, a brush method, or the like, and the developing solution may be an aqueous alkali solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, or an amine.

[0030] [2. Photosensitive resin composition] The photosensitive resin composition according to this embodiment contains (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a photopolymerizable monomer, (D) an epoxy resin, and (E) an organic pigment. Furthermore, the cured layer obtained by curing the photosensitive resin composition has the following optical properties (a) to (f). (a) Transmittance of 1% or more at a wavelength of 365 nm (b) Transmittance of 13% or more at a wavelength of 405 nm (c) Transmittance at wavelengths of 450 to 500 nm is 24% or less (d) The maximum transmittance in the wavelength range of 500 to 550 nm is 13% or more and 24% or less. (e) Transmittance at wavelengths of 550 to 725 nm is 24% or less (f) Transmittance at wavelengths of 750 to 850 nm is 13% or more

[0031] The transmittance of the photosensitive resin composition at each wavelength can be measured using an ultraviolet-visible-near-infrared spectrophotometer or the like, by forming a coating film of the photosensitive resin composition on a transparent substrate, drying the coating film using a hot plate or the like, heat-treating the coating film in a hot air oven or the like to form a resin layer, exposing the coating film to light to obtain a cured product layer, and using the transmittance of the transparent substrate at each wavelength as a reference. The transmittance can be measured, for example, by applying a photosensitive resin composition to a 2 mm thick glass substrate, drying it at 80°C for 30 minutes with an applicator, and then forming a resin layer to a thickness of 15 μm; alternatively, by laminating a dry film having a resin layer thickness of 15 μm onto a 2 mm thick glass substrate and peeling off the first film, the resin layer is formed, and then exposed using a high-pressure mercury lamp exposure device to obtain a cured product layer, which is then measured using a UV-visible-near-infrared spectrophotometer V-670 (manufactured by JASCO Corporation).

[0032] When the photosensitive resin composition has the optical properties (a) to (f) described above, the contrast ratio between reflected light in a wavelength region where the photosensitive resin composition has high transmittance and reflected light in a wavelength region where the photosensitive resin composition has low transmittance can be increased, and an electronic circuit board suitable for optical defect inspection can be produced.

[0033] [2-1. (A) Carboxyl group-containing resin] The photosensitive resin composition according to this embodiment contains (A) a carboxyl group-containing resin. The (A) carboxyl group-containing resin is not particularly limited, and any known or commonly used resin may be used as long as it contains a carboxyl group in the molecule. The carboxyl group-containing resin may be a carboxyl group-containing photosensitive resin having an ethylenically unsaturated group, or a carboxyl group-containing resin not having an ethylenically unsaturated group. (A) The carboxyl group-containing resin may be used alone or in combination of two or more. By incorporating (A) a carboxyl group-containing resin into a photosensitive resin composition, it becomes easier to form a pattern by alkaline development of a coating film formed from the photosensitive resin composition.

[0034] Specific examples of the carboxyl group-containing resin include the compounds (which may be either oligomers or polymers) listed below.

[0035] (1) Carboxyl group-containing resins obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid with unsaturated group-containing compounds such as styrene, α-methylstyrene, lower alkyl (meth)acrylates, and isobutylene.

[0036] (2) Carboxylic acid-containing urethane resins obtained by the polyaddition reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates with carboxyl-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, and diol compounds such as polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A alkylene oxide adduct diols, and compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups.

[0037] (3) Carboxylic acid group-containing photosensitive urethane resins obtained by the polyaddition reaction of diisocyanates with bifunctional epoxy resins such as bisphenol A epoxy resins, hydrogenated bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bixylenol epoxy resins, and biphenol epoxy resins, and monocarboxylic acid compounds having ethylenically unsaturated double bonds such as (meth)acrylic acid, partially acid anhydride-modified products thereof, carboxyl group-containing dialcohol compounds, and diol compounds.

[0038] (4) A carboxyl group-containing photosensitive urethane resin that is (meth)acrylated at the terminal by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule, such as hydroxyalkyl (meth)acrylate, during the synthesis of the resin (2) or (3).

[0039] (5) A carboxyl group-containing photosensitive urethane resin that is (meth)acrylated at the end by adding a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate, during the synthesis of the resin (2) or (3).

[0040] (6) A carboxyl group-containing photosensitive resin obtained by reacting a difunctional or more polyfunctional (solid) epoxy resin with (meth)acrylic acid and adding a dibasic acid anhydride to the hydroxyl group present in the side chain.

[0041] (7) A carboxyl group-containing photosensitive resin in which the hydroxyl groups of a bifunctional (solid) epoxy resin are further epoxidized with epichlorohydrin to form a multifunctional epoxy resin, which is then reacted with (meth)acrylic acid, and a dibasic acid anhydride is added to the resulting hydroxyl groups.

[0042] (8) Carboxyl group-containing polyester resins obtained by reacting a dicarboxylic acid such as adipic acid, phthalic acid, or hexahydrophthalic acid with a bifunctional oxetane resin, and then adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the resulting primary hydroxyl groups.

[0043] (9) A carboxyl group-containing photosensitive resin obtained by reacting an epoxy compound having multiple epoxy groups in one molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenethyl alcohol, and an unsaturated group-containing monocarboxylic acid, such as (meth)acrylic acid, and then reacting the alcoholic hydroxyl groups of the resulting reaction product with a polybasic acid anhydride, such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, or adipic acid.

[0044] (10) A carboxyl group-containing photosensitive resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide, reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0045] (11) A carboxyl group-containing photosensitive resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate, reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0046] (12) A carboxyl group-containing photosensitive resin obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule to the resins (1) to (11).

[0047] From the viewpoint of improving the alkaline developability of the photosensitive resin composition, the acid value of the carboxyl group-containing resin is preferably 20 to 180 mgKOH / g, more preferably 30 to 150 mgKOH / g, and even more preferably 40 to 120 mgKOH / g.

[0048] From the viewpoint of film-forming ability, the weight-average molecular weight of the carboxyl group-containing resin is preferably 3,000 to 30,000, more preferably 5,000 to 20,000, and even more preferably 7,000 to 15,000. The weight-average molecular weight can be determined from a standard polystyrene-equivalent value by gel permeation chromatography (GPC).

[0049] The amount of the carboxyl group-containing resin in the photosensitive resin composition is preferably 10 to 80 parts by mass, more preferably 15 to 70 parts by mass, and even more preferably 20 to 60 parts by mass, per 100 parts by mass of the total solid content in the photosensitive resin composition.

[0050] [2-2. (B) Photopolymerization initiator] The photosensitive resin composition according to this embodiment contains (B) a photopolymerization initiator. The (B) photopolymerization initiator is not particularly limited, and any known or commonly used photopolymerization initiator can be used. The photopolymerization initiator may be used alone or in combination of two or more.

[0051] Examples of the photopolymerization initiator include α-aminoacetophenone-based photopolymerization initiators such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, and N,N-dimethylaminoacetophenone; 1-hydroxy-cyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]; Hydroxyacetophenone-based photopolymerization initiators such as 2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, and 2-hydroxy-2-methyl-1-phenylpropan-1-one; bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, and bis-(2,6-dichlorobenzoyl)-4-propylphenyl Phosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide acylphosphine oxide-based photopolymerization initiators such as pivaloylphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphinic acid isopropyl ester, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; benzoin-based photopolymerization initiators such as benzoin, benzil, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, and benzoin n-butyl ether;Benzoin alkyl ether photopolymerization initiators; benzophenone photopolymerization initiators such as benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, and 4,4'-bisdiethylaminobenzophenone; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-( Acetophenone-based photopolymerization initiators such as [methylthio(phenyl)]-2-morpholino-1-propanone; thioxanthone-based photopolymerization initiators such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, and 2-tert-butylanthraquinone. Anthraquinone-based photopolymerization initiators such as 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone; ketal-based photopolymerization initiators such as acetophenone dimethyl ketal and benzil dimethyl ketal; benzoic acid ester-based photopolymerization initiators such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, and p-dimethylbenzoic acid ethyl ester; 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], ethanone, Examples of such photopolymerization initiators include oxime ester photopolymerization initiators such as 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime); and titanocene photopolymerization initiators such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium and bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyr-1-yl)ethyl)phenyl]titanium.

[0052] Commercially available α-aminoacetophenone-based photopolymerization initiators include, for example, Omnirad 907, 369, 369E, and 379 manufactured by IGM Resins. Commercially available acylphosphine oxide photopolymerization initiators include, for example, Omnirad 819 manufactured by IGM Resins. Commercially available titanocene photopolymerization initiators include, for example, JMT-784 manufactured by Yueyang Kimoutain Sci-tech Co., Ltd.

[0053] The amount of the photopolymerization initiator, excluding the oxime ester photopolymerization initiator, is preferably 0.5 to 10 parts by mass per 100 parts by mass of the total solid content in the photosensitive resin composition. When the amount is 0.5 parts by mass or more, the photocurability of the photosensitive resin composition is good, the cured product layer is less likely to peel, and coating properties such as chemical resistance are also good. On the other hand, when the amount is 10 parts by mass or less, the effect of reducing outgassing is obtained, and further, light absorption at the surface of the resin layer is good, and deep curing properties are not likely to decrease. Furthermore, the amount of the oxime ester photopolymerization initiator is preferably 0.1 to 5 parts by mass per 100 parts by mass of the total solid content in the photosensitive resin composition. When the amount is 0.1 part by mass or more, the photocurability of the photosensitive resin composition is good, and coating properties such as heat resistance and chemical resistance are also good. On the other hand, when the amount is 5 parts by mass or less, light absorption at the surface of the resin layer is good, and deep curing properties are not likely to decrease.

[0054] [2-3. (C) Photopolymerizable Monomer] The photosensitive resin composition according to this embodiment contains a photopolymerizable monomer (C). The photopolymerizable monomer (C) may be any monomer having an ethylenically unsaturated double bond in the molecule, and any known or commonly used monomer may be used.

[0055] Examples of photopolymerizable monomers include polyester (meth)acrylate, polyether (meth)acrylate, urethane (meth)acrylate, carbonate (meth)acrylate, and epoxy (meth)acrylate. Specifically, alkyl acrylates such as 2-ethylhexyl acrylate and cyclohexyl acrylate; hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; mono- or diacrylates of alkylene oxide derivatives such as ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol; acrylamides such as N,N-dimethylacrylamide, N-methylolacrylamide, and N,N-dimethylaminopropylacrylamide; aminoalkyl acrylates such as N,N-dimethylaminoethyl acrylate and N,N-dimethylaminopropyl acrylate; and various alkyl acrylates such as hexanediol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, and trishydroxyethyl isocyanurate. Polyhydric acrylates derived from hydroxyl alcohols or their alkylene oxide adducts or ε-caprolactone adducts; polyhydric acrylates such as phenols such as phenoxy acrylate and bisphenol A diacrylate or their alkylene oxide adducts; acrylates derived from glycidyl ethers such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether and triglycidyl isocyanurate; and, without being limited to the above, acrylates and melamine acrylates obtained by directly acridating polyols such as polyether polyols, polycarbonate diols, hydroxyl group-terminated polybutadienes and polyester polyols or by urethane acrylates via diisocyanates, and at least one of the methacrylates corresponding to the above acrylates can be appropriately selected and used.

[0056] The photopolymerizable monomer may be used alone or in combination of two or more. The amount of the photopolymerizable monomer is preferably 10 to 60 parts by mass relative to 100 parts by mass of the total solid content in the photosensitive resin composition. When the amount is 10 parts by mass or more, the photocurability is good, and pattern formation is easy in alkaline development after irradiation with active energy rays.

[0057] [2-4.(D) Epoxy Resin] The photosensitive resin composition according to this embodiment contains an epoxy resin (D). The epoxy resin (D) is not particularly limited, and any known or commonly used epoxy resin can be used.

[0058] The epoxy resin may be an epoxy resin having two or more epoxy groups in the molecule, and examples thereof include bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenol type epoxy resins, hydroquinone type epoxy resins, bisphenol fluorene type epoxy resins, naphthalene diol type epoxy resins, bisphenol S type epoxy resins, bisthioether type epoxy resins, resorcinol type epoxy resins, hydrogenated bisphenol A type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, and alkyl novolac type epoxy resins.

[0059] Commercially available epoxy resins include, for example, "jER828", "jER834", "jER1001", and "jER1004" manufactured by Mitsubishi Chemical Corporation; "Epiclon 840", "Epiclon 850", "Epiclon 1050", and "Epiclon 2055" manufactured by DIC Corporation; Epotohto "YD-011", "YD-013", "YD-127", and "YD-128" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "DER317", "DER331", "DER661", and "DER664" manufactured by Dow Chemical Japan Co., Ltd.; Sumi-Epoxy "ESA-011", "ESA-014", "ELA-115", and "ELA-128" manufactured by Sumitomo Chemical Co., Ltd.; and "AER330", "AER331", and "AER664" manufactured by Asahi Chemical Industry Co., Ltd. Bisphenol A epoxy resins such as AER661 and AER664; Mitsubishi Chemical Corporation's jER152 and jER154; Dow Chemical Japan's DEN431 and DEN438; DIC Corporation's Epicron N-730, Epicron N-770, and Epicron N-865; Nippon Steel Chemical & Material Co., Ltd.'s Epototo YDCN-701 and YDCN-704; Nippon Kayaku Co., Ltd.'s EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S, RE-306, and NC-3000H; Sumitomo Chemical Co., Ltd.'s Sumi-Epoxy ESCN-195X and ESCN-220; and Asahi Chemical Industry Co., Ltd.'s AER.Novolac epoxy resins such as "ECN-235" and "ECN-299"; bisphenol F epoxy resins such as "Epiclon 830" manufactured by DIC Corporation, "jER807" manufactured by Mitsubishi Chemical Corporation, and Epototo "YDF-170", "YDF-175", and "YDF-2004" manufactured by Nippon Steel Chemical & Material Co., Ltd.; and "TECHMORE" manufactured by Printec Co., Ltd. Trisphenol-type epoxy resins such as "VG3101L"; hydrogenated bisphenol A-type epoxy resins such as Epotohto "ST-2004", "ST-2007", "ST-3000", "ST-4000D", and "ST-6100" manufactured by Nippon Steel Chemical & Material Co., Ltd.; glycidyl amine-type epoxy resins such as "jER604" manufactured by Mitsubishi Chemical Corporation, Epotohto "YH-434" manufactured by Nippon Steel Chemical & Material Co., Ltd., and Sumi-Epoxy "ELM-120" manufactured by Sumitomo Chemical Co., Ltd.; hindatoin-type epoxy resins; alicyclic epoxy resins such as "Celloxide 2021·P" manufactured by Daicel Corporation and "CY179" manufactured by Huntsman Advanced Materials; "YL-933" manufactured by Mitsubishi Chemical Corporation, and "TEN" manufactured by Dow Chemical Japan Co., Ltd.trihydroxyphenylmethane-type epoxy resins such as "YL-6056," "YX-4000," and "YL-6121" manufactured by Mitsubishi Chemical Corporation; bixylenol-type or biphenol-type epoxy resins or mixtures thereof such as "EBPS-200" manufactured by Nippon Kayaku Co., Ltd., "EPX-30" manufactured by ADEKA Corporation, and "EXA-1514" manufactured by DIC Corporation; and bisphenol S-type epoxy resins such as "EBPS-200" manufactured by Nippon Kayaku Co., Ltd., "EPX-30" manufactured by ADEKA Corporation, and "EXA-1514" manufactured by Mitsubishi Chemical Corporation. Bisphenol A novolac epoxy resins such as "jER157S" manufactured by Mitsubishi Chemical Corporation; tetraphenylolethane epoxy resins such as "jERYL-931" manufactured by Mitsubishi Chemical Corporation; heterocyclic epoxy resins such as "TEPIC" manufactured by Nissan Chemical Co., Ltd.; diglycidyl phthalate resins such as "Blenmer DGT" manufactured by NOF Corporation; tetraglycidyl xylenoylethane resins such as "ZX-1063" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ES" manufactured by Nippon Steel Chemical & Material Co., Ltd. naphthalene group-containing epoxy resins such as "HP-4032", "EXA-4750", and "HP-4700" manufactured by DIC Corporation; dicyclopentadiene skeleton epoxy resins such as "HP-7200" and "HP-7200H" manufactured by DIC Corporation; and "890", "YL6810", "1750", "YX7700", "YX8000", "YX8034", "YX8800", "YL980", and "YL983U" manufactured by Mitsubishi Chemical Corporation. Special-function epoxy resins such as "YX7400N", "YX7105", "YX7110B80", and "YX7760"; flexible and tough epoxy resins such as "EXA-4816", "EXA-4822", and "EXA-4850" series manufactured by DIC Corporation; glycidyl methacrylate copolymer epoxy resins such as "CP-50S" and "CP-50M" manufactured by NOF Corporation; and copolymer epoxy resins of cyclohexylmaleimide and glycidyl methacrylate.

[0060] The amount of the epoxy resin blended is preferably 5 to 50 parts by mass, and more preferably 10 to 40 parts by mass, per 100 parts by mass of the total solid content in the photosensitive resin composition.

[0061] [2-5.(E) Organic pigments] The photosensitive resin composition according to this embodiment contains an organic pigment (E). The organic pigment (E) is not particularly limited, and any known or commonly used organic pigment can be used. As the organic pigment, known organic pigments such as red, blue, green, yellow, orange, purple, black, etc. can be used. However, from the viewpoint of reducing the environmental load and the effect on the human body, it is preferable that the pigment does not contain halogen.

[0062] Examples of organic pigments include monoazo, disazo, azo lake, benzimidazolone, perylene, diketopyrrolopyrrole, condensed azo, anthraquinone, quinacridone, and phthalocyanine pigments.

[0063] Examples of blue organic pigments include phthalocyanine pigments such as phthalocyanine, phthalocyanine blue, and fast sky blue; anthraquinone pigments; indigo pigments such as indigo blue; and indophenol pigments. Specific examples include Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 17, 17:1, 68, 75, 76, 79, 22, and 60.

[0064] Examples of yellow organic pigments include anthraquinone pigments such as Flavanthrone Yellow and Anthrapyrimidine Yellow, monoazo pigments such as Hansa Yellow, disazo pigments such as Benzidine Yellow and Permanent Yellow, condensed azo pigments such as Condensed Azo Yellow, and isoindoline pigments such as Isoindolinone Yellow. Specific examples include Pigment Yellow 24, 108, 112, 147, and 193.

[0065] Examples of red organic pigments include perylene pigments such as perylene scarlet, perylene red, and perylene maroon; anthraquinone pigments such as diaminoanthraquinolyl red; quinacridone pigments such as quinacridone red; azo pigments such as permanent carmine and permanent red; and condensed azo pigments such as condensed azo red. Specific examples include Pigment Red 123, 149, 178, 179, 190, and 224.

[0066] The organic pigments can be used alone or in combination. Among these, from the viewpoint of obtaining a photosensitive resin composition that can provide an electronic circuit board that is suitable for optical defect inspection while achieving both good resolution and hiding power, it is preferable to include one or more selected from phthalocyanine pigments, anthraquinone pigments, and perylene pigments, and it is more preferable to include both phthalocyanine pigments and perylene pigments.

[0067] The organic pigment can be appropriately blended so that the cured layer obtained by curing the photosensitive resin composition has the following optical properties (a) to (f). (a) Transmittance of 1% or more at a wavelength of 365 nm (b) Transmittance of 14% or more at a wavelength of 405 nm (c) Transmittance at wavelengths of 450 to 500 nm is 24% or less (d) The maximum transmittance in the wavelength range of 500 to 550 nm is 13% or more and 24% or less. (e) Transmittance at wavelengths of 550 to 725 nm is 24% or less (f) Transmittance at wavelengths of 750 to 850 nm is 13% or more

[0068] The method for blending the organic pigments is not particularly limited. For example, a cured material layer having the optical properties (a) to (f) above can be prepared by combining, in an appropriate ratio, one or more blue organic pigments selected from phthalocyanine pigments and anthraquinone pigments, one or more yellow organic pigments selected from anthraquinone pigments, and one or more red organic pigments selected from perylene pigments.

[0069] The method for blending the organic pigments is not particularly limited, and as just one example, the blending amounts of the blue organic pigment, yellow organic pigment, and red organic pigment are preferably 1 to 5 parts by mass of the blue organic pigment, 0 to 3 parts by mass of the yellow organic pigment, and 1 to 5 parts by mass of the red organic pigment, relative to 100 parts by mass of the carboxyl group-containing resin, as the total solid content in the photosensitive resin composition, and more preferably 1.5 to 4 parts by mass of the blue organic pigment, 0 to 2 parts by mass of the yellow organic pigment, and 1.5 to 4 parts by mass of the red organic pigment.

[0070] The amount of the (E) organic pigment in the photosensitive resin composition is not particularly limited, but is preferably 2 to 15 parts by mass, more preferably 2.5 to 12 parts by mass, and even more preferably 3 to 10 parts by mass, based on 100 parts by mass of the carboxyl group-containing resin, in terms of total solid content.

[0071] [2-6.Other] The photosensitive resin composition according to this embodiment may contain a black inorganic pigment, an inorganic filler, an antifoaming agent, other additive components, and the like.

[0072] [2-6-1. Black inorganic pigment] The black inorganic pigment used in the photosensitive resin composition according to this embodiment is not particularly limited, and any known or commonly used pigment may be used. These black inorganic pigments may be used alone or in combination of two or more.

[0073] Examples of black inorganic pigments include carbon black, titanium black, zirconium nitride, and iron oxide.

[0074] The blending amount of the black inorganic pigment is preferably 0.01 to 5 parts by mass, and more preferably 0.05 to 2 parts by mass, per 100 parts by mass of the total solid content in the photosensitive resin composition.

[0075] [2-6-2. Inorganic filler] The inorganic filler used in the photosensitive resin composition according to this embodiment is not particularly limited, and any known or commonly used inorganic filler can be used. These inorganic fillers may be used alone or in combination of two or more.

[0076] Examples of inorganic fillers include talc, silica, kaolin, montmorillonite, synthetic mica, hydrotalcite, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, gold, aluminum, copper, and nickel.

[0077] The shape of the inorganic filler is not particularly limited, and examples thereof include spherical, fibrous, plate-like, amorphous, and balloon-like shapes. The average particle size of the inorganic filler is also not particularly limited, and those having a particle size of, for example, 0.01 to 3.0 μm can be used. Furthermore, the inorganic filler may be subjected to various surface treatments, such as an insulating treatment or a high-dispersibility treatment, as needed.

[0078] The inorganic filler used in the present embodiment is preferably one selected from the group consisting of barium sulfate, talc, and silica, from the viewpoint of improving the adhesion of the cured layer obtained by curing the photosensitive resin composition after leveling treatment or gold plating treatment.

[0079] The amount of the inorganic filler to be blended is preferably 15 to 70 parts by mass, more preferably 20 to 60 parts by mass, even more preferably 25 to 55 parts by mass, and particularly preferably 30 to 50 parts by mass, relative to 100 parts by mass of the total solid content in the photosensitive resin composition.

[0080] [2-6-3. Defoaming agents] The defoaming agent used in this embodiment is not particularly limited, and any known or commonly used agent can be used, and among these, a silicone-based or acrylic copolymer-based defoaming agent can be preferably used.

[0081] Commercially available silicone-based antifoaming leveling agents include, for example, BYK-322 and BYK-333 manufactured by BYK and KS-66 manufactured by Shin-Etsu Chemical Co., Ltd. Commercially available acrylic copolymer-based antifoaming leveling agents include, for example, BYK-361N, BYK-1794, BYK-350, and BYK-1791 manufactured by BYK.

[0082] The amount of the antifoaming agent to be added is not particularly limited, and can be set to 0.1 to 10 parts by mass per 100 parts by mass of the total solid content in the photosensitive resin composition.

[0083] [2-6-4. Other additives] The photosensitive resin composition according to this embodiment may further contain, as necessary, components such as organic solvents, photopolymerization initiator aids, cyanate compounds, elastomers, mercapto compounds, curing catalysts, polymerization inhibitors, thixotropic agents, adhesion promoters, block copolymers, chain transfer agents, copper inhibitors, antioxidants, rust inhibitors, thickeners such as organic bentonite and montmorillonite, silane coupling agents such as imidazoles, thiazoles, and triazoles, and flame retardants such as phosphorus compounds such as phosphinates, phosphate ester derivatives, and phosphazene compounds. These may be known in the field of electronic materials.

[0084] [3. Dry film] The photosensitive resin composition according to this embodiment can also be in the form of a dry film comprising a first film and a resin layer formed on the first film, the resin layer being a dried coating of the photosensitive resin composition. In this embodiment, the first film refers to a film that is at least adhered to the resin layer when the dry film is laminated onto a substrate or other base material by heating or other means so that the resin layer formed on the dry film is in contact with the resin layer formed on the dry film and integrally molded. The first film may be peeled from the resin layer in a post-lamination step. In this embodiment, it is particularly preferable to peel it from the resin layer in a post-exposure step. To form the dry film, the photosensitive resin composition according to this embodiment is diluted with an organic solvent to an appropriate viscosity, and then coated to a uniform thickness on the first film using a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, or the like. The film is typically dried at a temperature of 50 to 130°C for 1 to 30 minutes to obtain a film. There are no particular restrictions on the thickness of the coating film, but it is generally selected appropriately within the range of 1 to 150 μm, preferably 10 to 60 μm, in terms of the thickness after drying.

[0085] The first film can be any known film without particular limitation, and examples of suitable films include polyester films such as polyethylene terephthalate and polyethylene naphthalate, and films made of thermoplastic resins such as polyimide films, polyamideimide films, polypropylene films, and polystyrene films. Among these, polyester films are preferred from the viewpoints of heat resistance, mechanical strength, ease of handling, etc. A laminate of these films can also be used as the first film.

[0086] From the viewpoint of improving mechanical strength, the thermoplastic resin film as described above is preferably a film stretched in a uniaxial or biaxial direction.

[0087] The thickness of the first film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0088] After forming a resin layer of the photosensitive resin composition according to this embodiment on the first film, it is preferable to further laminate a peelable second film on the surface of the resin layer for the purpose of preventing dust from adhering to the surface of the resin layer. The second film in this embodiment refers to a film that is peeled off from the resin layer before lamination when the resin layer side of the photosensitive film laminate is laminated onto a base material such as a substrate by heating or the like so as to be in contact with the substrate and integrally molded. Examples of the peelable second film that can be used include polyethylene film, polytetrafluoroethylene film, polypropylene film, and surface-treated paper, as long as the adhesive strength between the resin layer and the second film is smaller than the adhesive strength between the resin layer and the first film when the second film is peeled off.

[0089] The thickness of the second film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0090] In this embodiment, the photosensitive resin composition according to this embodiment may be applied to the second film and dried to form a resin layer, and the first film may be laminated on the surface of the resin layer. That is, in this embodiment, when producing a dry film, either the first film or the second film may be used as the film to which the photosensitive resin composition according to this embodiment is applied. [Example]

[0091] EXAMPLES The present invention will be specifically explained below by showing examples, but the present invention is not limited to these examples.

[0092] [1. Synthesis of carboxyl group-containing resin] To 650 parts by mass of diethylene glycol monoethyl ether acetate, 1070 g of orthocresol novolac epoxy resin (EPICLON N-695, manufactured by DIC Corporation, softening point 95°C, epoxy equivalent 214, average functionality 7.6), 360 g of acrylic acid, and 1.5 g of hydroquinone were added, and the mixture was heated to 100°C with stirring to dissolve uniformly. Next, 4.3 parts by mass of triphenylphosphine was added, and the mixture was heated to 110°C and reacted for 2 hours, after which 1.6 parts by mass of triphenylphosphine was further added, the mixture was heated to 120°C, and the reaction was continued for a further 12 hours. To the resulting reaction solution, 525 g of an aromatic hydrocarbon (T-Sol 150, manufactured by Standard Oil Corporation, Osaka Sales Office) and 608 g (4.0 mol) of tetrahydrophthalic anhydride were added, and the reaction was carried out for 4 hours at 110° C. Furthermore, 142.0 g of glycidyl methacrylate was added to the resulting reaction solution, and the reaction was carried out for 4 hours at 115° C. In this way, a solution of carboxyl group-containing resin 1 was obtained, which had a solid content of 65% by mass and an acid value of the solid content of 77 mgKOH / g.

[0093] In a flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser, 325.0 parts by mass of dipropylene glycol monomethyl ether as a solvent was heated to 110°C, and a mixture of 174.0 parts by mass of methacrylic acid, 174.0 parts by mass of ε-caprolactone-modified methacrylic acid (average molecular weight 314), 77.0 parts by mass of methyl methacrylate, 222.0 parts by mass of dipropylene glycol monomethyl ether, and 12.0 parts by mass of t-butylperoxy 2-ethylhexanoate (Perbutyl O, manufactured by NOF Corporation) as a polymerization catalyst was added dropwise over 3 hours, and the mixture was stirred at 110°C for a further 3 hours to deactivate the polymerization catalyst, thereby obtaining a resin solution. After cooling this resin solution, 289.0 parts by mass of Cyclomer M100 (manufactured by Daicel Allnex Corporation), 3.0 parts by mass of triphenylphosphine, and 1.3 parts by mass of hydroquinone monomethyl ether were added, and the temperature was raised to 100°C and the mixture was stirred to carry out a ring-opening addition reaction of the epoxy groups. In this way, a solution of carboxyl group-containing resin 2 was obtained, having a solid content of 45.5% by mass and an acid value of the solid matter of 79.8 mgKOH / g.

[0094] 2. Preparation of Test Photosensitive Resin Composition The carboxyl group-containing resin, photopolymerization initiator, photopolymerizable monomer, epoxy resin, organic pigment, black inorganic pigment, inorganic filler, and antifoaming agent were blended in the amounts (unit: parts by mass) shown in Table 1, premixed by stirring, and then kneaded with a three-roll mill to prepare the test photosensitive resin compositions of Examples 1 to 7 and Comparative Examples 1 to 3.

[0095] The details of each component listed in Table 1 are as follows. The blend amount of each component is the value in solid content. <(A) Carboxyl group-containing resin> *1: Carboxyl group-containing resin 1 synthesized above *2: Carboxyl group-containing resin 2 synthesized above <(B) Photopolymerization initiator> Omnirad 379 (IGM Resins): 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one ·JMT-784 (manufactured by Yueyang Kimoutain Sci-tech Co., Ltd.): Screw (η 5 -2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium <(C) Photopolymerizable Monomer> A-9550 (Shin-Nakamura Chemical Co., Ltd.): Dipentaerythritol polyacrylate <(D) Epoxy resin> N-870 (DIC Corporation): Bisphenol A novolac epoxy resin (epoxy equivalent weight 205) <(E) Organic pigments> FASTOGEN BLUE FA5380 (DIC Corporation, CI Pigment Blue 15:3): Phthalocyanine blue pigment Cromophtal Yellow AGR (CI Pigment Yeiiow 147): Anthraquinone yellow pigment Paliogen Red K 3580 (BASF, CI Pigment Red 149): Perylene-based red pigment <(F) Black inorganic pigment> MA-100 (Mitsubishi Chemical Corporation): Carbon black TilackD TM-B (Ako Kasei Co., Ltd.): Titanium Black <(G) Inorganic filler> B-30 (Sakai Chemical Industry Co., Ltd.): Barium sulfate ACEMATT82 (EVONIK DEGUSSA): Silica LMP-100 (Fuji Talc Co., Ltd.): Talc <(H) Antifoaming Agent> KS-66 (Shin-Etsu Chemical Co., Ltd.): Silicone antifoaming leveling agent BYK-1791 (BYK): Acrylic copolymer defoaming and leveling agent

[0096] [Table 1]

[0097] [3. Transmittance] The prepared test photosensitive resin composition was applied to a 2 mm thick glass substrate using an applicator to form a resin layer with a thickness of 15 μm after drying at 80°C for 30 minutes. Test cured product layers were then produced by exposure using a high-pressure mercury lamp exposure device. The transmittance of each test cured product layer was measured using a V-670 ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation). The transmittance of each test cured product layer in each wavelength region under the following conditions (a) to (f) was evaluated to determine whether it was within the specified transmittance range. The results are shown in Table 1. In Table 1, conditions (a) to (f) that met the conditions were indicated as ○, and conditions that did not met the conditions were indicated as ×. Condition (a): Transmittance of 1% or more at a wavelength of 365 nm Condition (b): Transmittance of 13% or more at a wavelength of 405 nm Condition (c): Transmittance at wavelengths of 450 to 500 nm is 24% or less Condition (d): The maximum transmittance in the wavelength range of 500 to 550 nm is 13% or more and 24% or less. Condition (e): Transmittance at wavelengths of 550 to 725 nm is 24% or less Condition (f): Transmittance at wavelengths of 750 to 850 nm is 13% or more

[0098] [4. Concealment and L * Test method and evaluation criteria for values] An interdigital electrode with a residual copper ratio of 70% and an L / S ratio of 100 μm / 100 μm was formed on an FR-4 substrate. The test photosensitive resin compositions of Examples 1 to 7 and Comparative Examples 1 to 3 were applied to the substrate by screen printing so that the film thickness after drying was 20 μm, and the composition was dried in a hot air circulation oven at 80°C for 30 minutes. Next, a test substrate having a cured product layer was produced by exposure using a high-pressure mercury lamp exposure device.

[0099] The test substrates thus prepared were visually observed from a distance of 30 cm, and the concealment of the wiring pattern was evaluated according to the following criteria. The results are shown in Table 1. ○: Wiring pattern is not visible ×: The wiring pattern is visible.

[0100] The appearance color of the cured product layer on the test substrate was measured using a spectrophotometer CM-2600d (manufactured by Konica Minolta Japan, Inc.) and expressed as L in the CIE 1976 color system. * The values ​​were calculated. * The values ​​were measured in accordance with JIS Z 8781. The cured product layers obtained by curing the test photosensitive resin compositions of Examples 1 to 7 and Comparative Examples 1 and 2 were all L * In contrast, the cured layer obtained by curing the photosensitive resin composition of Comparative Example 3 gave a value of L * The value was 30.

[0101] [5. Resolution test method and evaluation criteria] <Resolution on copper foil> The photosensitive resin compositions of Examples 1 to 7 and Comparative Examples 1 to 3 were applied to the entire surface of the copper foil of a copper-clad laminate by screen printing so that the film thickness after drying would be 15 μm, and then dried in a hot air circulation drying oven at 80°C for 30 minutes. After drying, the resin layer on the test copper foil was exposed to light using a high-pressure mercury lamp exposure device. A quartz glass mask was used to create an exposure pattern with circular holes with an opening diameter of 100 μm. After leaving the sample to stand at room temperature for 30 minutes, the sample was spray-developed with a 1% by mass aqueous solution of sodium carbonate at 30°C as the developer at a spray pressure of 0.2 MPa for 1 minute. After spray development, the sample was exposed to light at a pressure of 2 J / cm. 2 The cured product layer was then fully cured by heating at 170°C for 1 hour.

[0102] The sensitivity of the photosensitive resin composition was determined as the amount of exposure energy required to produce 20 gloss-remaining steps on a 41-step tablet. Via holes patterned on the cured product layer on copper foil exposed at this sensitivity were observed with an SEM (1000x magnification). The radius (μm) of the top and bottom cross sections of the via holes with an opening diameter of 100 μm were measured with the SEM, and the difference between the bottom and top radii (bottom radius - top radius) was calculated. The calculated value was considered undercut, and the resolution of the cured product layer on the copper foil was evaluated according to the following criteria. The results are shown in Table 1. ○: Undercut is 20 μm or less △: Undercut is less than 30 μm ×: Undercut is 30 μm or more

[0103] <Resolution on base material> The test photosensitive resin compositions of Examples 1 to 7 and Comparative Examples 1 to 3 were applied by screen printing to the entire surface of a glass epoxy substrate from which the copper foil of a copper-clad laminate had been etched away, and then dried in a hot air circulating drying oven at 80°C for 30 minutes. After drying, the resin layer on the test substrate was exposed to light using a high-pressure mercury lamp exposure device. A quartz glass mask was used to create an exposure pattern with circular holes with an opening diameter of 100 μm. After leaving the substrate to stand at room temperature for 30 minutes, development was carried out by spraying a 1% by mass aqueous solution of sodium carbonate at 30°C as a developer at a spray pressure of 0.2 MPa for 1 minute. After spray development, the coating was exposed to light at a pressure of 2 J / cm. 2 The cured product layer was then fully cured by heating at 170°C for 1 hour.

[0104] The resolution of the cured product layer on the substrate was evaluated using the same method and criteria as in the evaluation of the resolution on the copper foil. The results are shown in Table 1.

[0105] [6. Evaluation of Test Photosensitive Resin Composition and Cured Layer Obtained by Curing the Same] From the results of the evaluation of the hiding power in Table 1, when the transmittance of the cured product layer at a wavelength of 365 nm was 1% or more and the transmittance at 405 nm was 13% or more, as in the case of the photosensitive resin composition of Comparative Example 3, both the resolution on the copper foil and the resolution on the substrate were good. On the other hand, the photosensitive resin composition of Comparative Example 3 had a region where the transmittance of the cured product layer at a wavelength of 450 to 500 nm was greater than 24%, the maximum transmittance in the wavelength region of 500 to 550 nm was greater than 24%, and there was a region where the transmittance in the wavelength region of 550 to 725 nm was greater than 24%, so the hiding power of the wiring pattern was reduced, and the L * The value was 30. In contrast, when the transmittance of the cured product layer at a wavelength of 365 nm was less than 1% or the transmittance at a wavelength of 405 nm was less than 13%, as in the case of the photosensitive resin compositions of Comparative Examples 1 and 2, the results showed that the resolution on the copper foil and the resolution on the substrate were poor. Furthermore, when the resolution on the copper foil and the substrate of the photosensitive resin composition of Comparative Example 1 was compared, the photosensitive resin composition of Comparative Example 1 was evaluated as fair for its resolution on the copper foil, but poor for its resolution on the substrate, because the bottom of the photosensitive resin composition on the copper foil was more likely to be cured due to reflection from the copper.

[0106] Furthermore, Table 1 shows that when the optical properties (a) to (f) of the cured product layer are satisfied, as in the case of the photosensitive resin compositions of Examples 1 to 7, the resolution on the copper foil and the substrate is generally good and good hiding power is also provided. Furthermore, by having the cured product layer obtained by curing the photosensitive resin composition have the optical properties (a) to (f) above, it is possible to establish a contrast ratio between reflected light in a wavelength range where the photosensitive resin composition has high transmittance and reflected light in a wavelength range where the photosensitive resin composition has low transmittance. This makes it possible to distinguish between areas where the cured product layer forms part of the surface of the electronic circuit board and areas where the cured product layer is not present, facilitating automatic optical defect inspection of the electronic circuit board.

Claims

1. An electronic circuit board having a substrate, a wiring pattern, and a cured layer obtained by curing a photosensitive resin composition, the cured material layer constitutes a part of the surface of the electronic circuit board, The cured material layer is (a) the transmittance at a wavelength of 365 nm is 1% or more; (b) the transmittance at a wavelength of 405 nm is 13% or more; (c) the transmittance at wavelengths of 450 to 500 nm is 24% or less; (d) the maximum transmittance in the wavelength region of 500 to 550 nm is 13% or more and 24% or less; (e) the transmittance at wavelengths of 550 to 725 nm is 24% or less; (f) The transmittance at a wavelength of 750 to 850 nm is 13% or more; Electronic circuit board.

2. L of the cured material layer ＊ The value is 26 or less, The electronic circuit board according to claim 1 .

3. the cured material layer has a line / space of 100 μm / 100 μm or less and via holes with an opening diameter of 100 μm or less; The electronic circuit board according to claim 1 .

4. 2. The electronic circuit board according to claim 1, wherein the cured product layer is formed on a substrate or a wiring pattern having a residual copper ratio of 60% or more.

5. The photosensitive resin composition is (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a photopolymerizable monomer, (D) an epoxy resin, and (E) Organic pigments containing The electronic circuit board according to claim 1 .

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