Photosensitive resin composition, dry film, cured product, and printed wiring board

Abstract

[Problem] To provide a photosensitive resin composition having excellent resolution and deep curability even in a photosensitive resin composition containing a predetermined amount of an inorganic filler. [Solution] A photosensitive resin composition characterized by containing at least (A) an alkali-soluble resin, (B) a photopolymerization initiator including an acylphosphine oxide-based photopolymerization initiator and a titanocene-based photopolymerization initiator, (C) a sensitizing agent including an anthracene-based sensitizing agent, (D) an inorganic filler, and (E) a photopolymerizable monomer, the photopolymerization initiator (B) including an acylphosphine oxide-based photopolymerization initiator and a titanocene-based photopolymerization initiator, and the sensitizing agent (D) including an inorganic filler. The inorganic filler (D) is contained in a ratio of 50-90% by mass with respect to the total solid content in the photosensitive resin composition, and the average particle diameter (D50) of the inorganic filler (D) is 0.1-1.0 m.

Description

Technical Field

[0001] This invention relates to photosensitive resin compositions, and more specifically to photosensitive resin compositions suitable for forming insulating layers such as solder resist films, dry films using photosensitive resin compositions, cured products of photosensitive resin compositions or dry films, and printed wiring boards using these cured products. Background Technology

[0002] Generally, in printed circuit boards (PCBs) used in electronic devices, a solder resist layer is formed in areas other than the interconnect holes on the substrate with the circuit pattern to prevent solder from adhering to unwanted parts of the PCB during reflow soldering and other steps when mounting electronic components onto the PCB. Currently, the mainstream method involves coating a photosensitive resin composition onto the substrate, drying it, and then forming a pattern through exposure and development. The patterned resin is then cured by heating or even light irradiation, a process known as photoresist. Alternatively, a method has been proposed that uses a photosensitive dry film to form the solder resist layer instead of the liquid photosensitive resin composition described above.

[0003] In such photosensitive resin compositions and photosensitive dry films, alkali-soluble photosensitive resin components are included to enable exposure and development. Other photopolymerizable monomers may also be included as needed, or thermosetting components such as epoxy may be included to consider heat resistance and substrate adhesion. In addition, inorganic fillers are sometimes mixed into the photosensitive resin composition to reduce the coefficient of linear expansion and suppress solder mask peeling and substrate warping (Patent Document 1, etc.).

[0004] However, in the field of photosensitive resin compositions, high resolution is required for insulating layers such as solder resist films in order to handle the fine patterning of wiring. For example, focusing on initiators used in photosensitive resin compositions, it has been proposed that excellent resolution can be obtained by using specific initiators together (Patent Document 2, etc.).

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2001-72834 Patent Document 2: Japanese Patent Application Publication No. 2013-228758 Summary of the Invention

[0006] The problem to be solved by the present invention As mentioned above, inorganic fillers such as silica are widely used to improve the properties of solder resist films due to their low coefficient of thermal expansion. However, inorganic fillers generally have low light transmittance, leading to a problem that as the amount of inorganic filler increases, the light during exposure has difficulty reaching the bottom of the coating film of the photosensitive resin composition. Furthermore, the refractive index of the resin components constituting the photosensitive resin composition differs from that of the inorganic fillers, causing light incident on the coating film to scatter during exposure, resulting in a phenomenon where the resolution decreases towards the bottom (undercut).

[0007] Therefore, the object of the present invention is to provide a photosensitive resin composition that still exhibits excellent resolution and deep curing properties even in a photosensitive resin composition containing a predetermined amount of inorganic filler.

[0008] Methods for solving problems In view of the above-mentioned problems, the inventors of this application, after conducting research, learned that when using only a specific photopolymerization initiator as proposed in Patent Document 2, which is believed to improve resolution, the resolution is insufficient if the photosensitive resin composition has a high content of inorganic fillers. Further research led to the following insight: by using a specific initiator and a specific sensitizer together, a photosensitive resin composition with excellent resolution can be obtained even with a high content of inorganic fillers. This invention is derived according to this insight. In other words, the gist of this invention is as follows.

[0009] [1] A photosensitive resin composition, characterized in that it comprises at least (A) an alkali-soluble resin, (B) a photopolymerization initiator, (C) a sensitizer, (D) an inorganic filler, and (E) a photopolymerizable monomer. The photopolymerization initiator (B) includes acylphosphine oxide-based photopolymerization initiators and titanium lithocene-based photopolymerization initiators. The sensitizer (C) comprises anthracene-based sensitizers. The inorganic filler (D) is contained in the photosensitive resin composition at a ratio of 50-90% by mass relative to all solid components. The average particle size (D50) of the (D) inorganic filler is 0.1~1.0µm.

[0010] [2] The photosensitive resin composition as described in [1], wherein the acylphosphine oxide photopolymerization initiator and the titanium cadmium photopolymerization initiator are contained in a ratio of 10:1 to 90:1 by weight.

[0011] [3] The photosensitive resin composition as described in [1], wherein the (C) sensitizer is contained in a proportion of 2 to 18% by weight relative to the (B) photopolymerization initiator.

[0012] [4] The photosensitive resin composition as described in [1], wherein the (D) inorganic filler comprises silica.

[0013] [5] The photosensitive resin composition as described in [1] further comprises (F) a thermosetting component.

[0014] [6] A dry film comprising: a first film; and a resin layer obtained by coating a one side of the first film with the photosensitive resin composition as described in [1] and drying it.

[0015] [7] A cured product formed by curing a photosensitive resin composition of any one of [1] to [5] or a resin layer of a dry film as described in [6].

[0016] [8] A printed wiring board having a coating made of a cured material as described in [7].

[0017] The effects of the invention According to the present invention, by using two specific photopolymerization initiators and a specific sensitizer together, excellent resolution and deep curing properties can still be achieved even in photosensitive resin compositions containing inorganic fillers having a predetermined average particle size in the range of 50 to 90% by mass. Attached Figure Description

[0018] Figure 1 A schematic cross-sectional view of the solder mask used to illustrate the evaluation of resolution. Detailed Implementation

[0019] [Photosensitive Resin Composition] The photosensitive resin composition of the present invention comprises at least (A) an alkali-soluble resin, (B) a photopolymerization initiator, (C) a sensitizer, (D) an inorganic filler, and (E) a photopolymerizable monomer. Hereinafter, each component constituting the photosensitive resin composition will be described. Furthermore, in this specification, (meth)acrylic acid is used as a general term for both acrylic acid and methacrylic acid. Additionally, (meth)acryloyl is used as a general term for both acryloyl and methacryloyl groups. Further, (meth)acrylate is used as a general term for acrylates, methacrylates, and mixtures thereof.

[0020] <(A) Alkali-soluble resin> In the photosensitive resin composition of the present invention, the (A) alkali-soluble resin can be any type of alkali-soluble resin, and commonly known substances can be used. One type of alkali-soluble resin can be used alone or in combination of two or more. Examples include water-soluble resins such as carboxyl-containing resins and phenolic hydroxyl-containing resins. Among these, carboxyl-containing resins and phenolic hydroxyl-containing resins are preferred for their superior developability, and carboxyl-containing resins are more preferred. Alkali-soluble resins can achieve alkaline developability by including carboxyl groups. Furthermore, from the viewpoint of photosensitivity, in addition to having carboxyl groups, it is preferable to have vinyl unsaturated double bonds within the molecule, but it is also possible to use only carboxyl-containing resins that do not have vinyl unsaturated double bonds. In the case where the carboxyl-containing resin does not have vinyl unsaturated double bonds, a photopolymerizable monomer must be used in conjunction to achieve photocurability of the composition. Vinyl unsaturated double bonds are preferably derived from acrylic acid, methacrylic acid, or derivatives thereof.

[0021] Specific examples of carboxyl-containing resins include, for example, the following compounds (which may be either oligomers or polymers). Furthermore, in this specification, "(meth)acrylate" is a general term for acrylates, methacrylates, and mixtures thereof, as are other similar expressions.

[0022] (1) A carboxyl-containing resin obtained by copolymerization of unsaturated carboxylic acids such as (meth)acrylic acid with styrene, α-methylstyrene, lower alkyl (meth)acrylates, isobutylene and other compounds containing unsaturated groups.

[0023] (2) A carboxyl-containing urethane resin obtained by polyaddition reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates, as well as carboxyl-containing diol compounds such as dimethylolpropionic acid and dimethylolbutyric acid, and diol compounds such as polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A epoxy alkyl adduct diols, and compounds with phenolic hydroxyl and alcoholic hydroxyl groups.

[0024] (3) A carboxyl-containing photosensitive urethane resin obtained by polyaddition reaction of a partially modified acid anhydride product of a reaction product of diisocyanate, bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin, and monocarboxylic acid compounds with vinyl unsaturated double bonds such as (meth)acrylic acid, with carboxyl-containing diol compounds and diol compounds.

[0025] (4) In the synthesis of the resin in (2) or (3) above, a carboxyl-containing photosensitive urethane resin is obtained by adding a compound such as (meth)acrylate hydroxyalkyl ester with one hydroxyl group and one or more (meth)acryloyl groups in the molecule and performing terminal (meth)acryloylation.

[0026] (5) In the synthesis of the resin in (2) or (3) above, a compound having one isocyanate group and one or more (meth)acryloyl groups in the equimolar reactants of isophorone diisocyanate and neopentyl tertetrol triacrylate is added and terminally (meth)acryloylated to obtain a carboxyl-containing photosensitive urethane resin.

[0027] (6) A carboxyl-containing photosensitive resin is obtained by reacting (meth)acrylic acid with a polyfunctional (solid) epoxy resin with two or more functions and adding a dibasic acid anhydride to a hydroxyl group present in the side chain.

[0028] (7) A multifunctional epoxy resin containing carboxyl groups is obtained by reacting (meth)acrylic acid with the hydroxyl groups of a difunctional (solid) epoxy resin with epichlorohydrin to further epoxidize the hydroxyl groups, thereby adding a dibasic acid anhydride to the generated hydroxyl groups.

[0029] (8) A dicarboxylic acid such as adipic acid, phthalic acid, and hexahydrophthalic acid is reacted with a difunctional oxobutane resin to add phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and other dibasic anhydrides to the generated primary hydroxyl group to obtain a carboxyl-containing polyester resin.

[0030] (9) A carboxyl-containing photosensitive resin is obtained by reacting a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenylethanol, and a monocarboxylic acid containing an unsaturated group, such as (meth)acrylic acid, with an epoxy compound having multiple epoxy groups in one molecule, and by reacting the alcoholic hydroxyl group of the obtained reaction product with polyacid anhydride such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyrolithic anhydride, and adipic anhydride.

[0031] (10) A carboxyl-containing photosensitive resin is obtained by reacting a compound with multiple phenolic hydroxyl groups in one molecule with ethylene oxide, propylene oxide and other epoxides, reacting the product with a monocarboxylic acid containing an unsaturated group, and reacting the product with a polyacid anhydride.

[0032] (11) A carboxyl-containing photosensitive resin is obtained by reacting a compound with multiple phenolic hydroxyl groups in one molecule with cyclic carbonate compounds such as ethyl carbonate and propyl carbonate, reacting the product with a monocarboxylic acid containing an unsaturated group, and reacting the product with a polyacid anhydride.

[0033] (12) A carboxyl-containing photosensitive resin obtained by further adding one molecule of a compound having one epoxy group and one or more (meth)acryloyl groups to the resin described in (1) to (11) above.

[0034] These carboxyl-containing resins can be used in addition to the substances listed above, and can be used alone or in combination. Among the above substances, carboxyl-containing resins such as (10) and (11), which are synthesized from compounds with phenolic hydroxyl groups as starting materials, are preferred because of their excellent HAST resistance and PCT resistance.

[0035] The acid value of the carboxyl-containing resin is preferably 40-150 mg KOH / g. With an acid value of 40 mg KOH / g or higher, alkaline development becomes better. Furthermore, with an acid value of 150 mg KOH / g or lower, it is easier to draw good resist patterns. More preferably, it is 50-130 mg KOH / g.

[0036] The weight-average molecular weight of carboxyl-containing resins varies depending on the resin skeleton, but is generally preferred to be between 2,000 and 150,000. A weight-average molecular weight of 2,000 or higher improves non-stickiness and resolution. Conversely, a weight-average molecular weight of 150,000 or lower improves developability and storage stability. A further preferred value is 5,000 to 15,000. Furthermore, the weight-average molecular weight can be obtained from the standard polystyrene conversion value obtained by gel permeation chromatography (GPC).

[0037] In the photosensitive resin composition, the amount of the alkali-soluble resin (A) described above, converted from solid content, is preferably 10 to 50% by mass. By having an amount of 10% by mass or more, the coating strength can be improved. Furthermore, by setting the amount of 50% by mass or less, the viscosity becomes suitable and the printability is improved. More preferably, it is 10 to 30% by mass.

[0038] <(B) Photopolymerization Initiator> The photosensitive resin composition of the present invention comprises (B) a photopolymerization initiator to photopolymerize the aforementioned (A) alkali-soluble resin or the (D) photopolymerizable monomer described later. The present invention includes an acylphosphine oxide-based photopolymerization initiator and a titanium-based photopolymerization initiator as (B) the photopolymerization initiator. By using both the acylphosphine oxide-based and titanium-based photopolymerization initiators as photopolymerization initiators, absorption and reactivity are improved not only in the short wavelength region but also in the long wavelength region, resulting in improved resolution.

[0039] Acylphosphine oxide-based photopolymerization initiators can be any known photopolymerization initiator. Specific examples of acylphosphine oxide-based photopolymerization initiators include: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, ethyl(2,4,6-trimethylbenzoyl)phenyl isophosphine ester, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, etc. These acylphosphine oxide-based photopolymerization initiators can be used alone or in combination of two or more.

[0040] Relative to 100 parts by weight of the carboxyl-containing resin in (A), the content of the acylphosphine oxide-based photopolymerization initiator in (B) is preferably 0.5 to 50 parts by weight, more preferably 1 to 30 parts by weight.

[0041] Regarding the diacene-based photopolymerization initiator used in conjunction with acylphosphine oxide-based photopolymerization initiators, any known photopolymerization initiator having a diacene structure may be used. Specific examples of titanium cadmium-based photopolymerization initiators include: bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyrrolo-1-yl)ethyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(3-(1-pyrrolo-1-yl)propyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-((1-pyrrolo-1-yl)methyl)phenyl]titanium, bis(methylcyclopentadienyl)-bis[2,6-difluoro-3-((1-pyrrolo-1-yl)methyl)phenyl]titanium, and bis(cyclopentadienyl)-bis[2,6-difluoro-3-((2,5-dimethyl-1-pyrrolo-1-yl)methyl)phenyl]titanium. , bis(cyclopentadienyl)-bis[2,6-difluoro-3-((2-isopropyl-5-methyl-1-pyrrolo-1,6-yl)methyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-((2-(2-methoxyethyl)-5-methyl-1-pyrrolo-1-yl)methyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-((3-trimethylsilyl-2,5-dimethyl-1-pyrrolo-1-yl)methyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-((2,5-dimethyl-3-(bis(2-methoxyethyl)aminomethyl)-1-pyrrolo-1-yl)methyl)phenyl]titanium, bis( Cyclopentadienyl)-bis[2,6-difluoro-3-((2,5-bis(morpholinylmethyl)-1-pyrrolo-1-yl)methyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-((2,5-dimethyl-3-(1,3-dioxolane-2-yl)-1-pyrrolo-1-yl)methyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-4-((2,5-dimethyl-1-pyrrolo-1-yl)methyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-methyl-4-(2-(1-pyrrolo-1-yl)ethyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-methyl-4-(2-(1-pyrrolo-1-yl)ethyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-((2- ... [3,4,5-Tetramethyl-1-pyrrolo-1-yl)methyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,3,5,6-tetrafluoro-4-(3-(1-pyrrolo-1-yl)propyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyrrolo-1-yl)propyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(1-methyl-2-(1-pyrrolo-1-yl)ethyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(3-(2-isoindol-2-yl)propyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(3-(2-isoindol-2-yl)propyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(4,5,6,7-Tetrahydro-isoindol-2-yl)ethyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(6-(9-carbazol-9-yl)hexyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(3-(2,3,4,5,6,7,8,9-octahydro-1-carbazol-9-yl)propyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(3-(4,5,6,7-tetrahydro-2-methyl-1-indol-1-yl)propyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-((acetamido)methyl)phenyl]titanium, bis(cyclopentadienyl) Bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(propamido)ethyl)phenyl]titanium, Bis(cyclopentadienyl)-bis[2,6-difluoro-3-(3-(acetamido)propyl)phenyl]titanium, Bis(cyclopentadienyl)-bis[2,6-difluoro-3-(4-(trimethylacetamido)butyl)phenyl]titanium, Bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(2,2-dimethylpentamido)ethyl)phenyl]titanium, Bis(cyclopentadienyl)-bis[2,6-difluoro-3-(3-(benzamido)propyl)phenyl]titanium, Bis(cyclopentadienyl)-bis[2,6-difluoro-3-(3-(2,2-dimethylpentamido)ethyl ... [Amamido)methyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(2,2-dimethyl-3-chloropropamido)ethyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-((2,2-dimethyl-3-ethoxypropamido)methyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(lauroylamino)ethyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(N-enylmethylsulfonylamino)ethyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(N-isobutyl) Titanium bis(cyclopentadienyl)-bis[2,6-difluoro-3-((methylsulfonylamino)methyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(3-(ethylsulfonylamino)propyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(butylsulfonylamino)ethyl)phenyl]titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(4-(trisulfonylamino)propyl)phenyl]titanium, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)phenyl)titanium, etc. These titanium biscarbonate photopolymerization initiators can be used alone or in combination of two or more.

[0042] Relative to 100 parts by weight of carboxyl-containing resin in (A), the content of titanium-ceramic photopolymerization initiator in (B) is preferably 0.01 to 10 parts by weight, more preferably 0.01 to 8 parts by weight.

[0043] Furthermore, in this invention, as the (B) photopolymerization initiator, the acylphosphine oxide-based photopolymerization initiator and the titanium cadmium-based photopolymerization initiator are preferably contained in a ratio of 10:1 to 90:1 by mass, and more preferably in a ratio of 15:1 to 50:1.

[0044] In this invention, known photopolymerization initiators other than the aforementioned acylphosphine oxide-based and titanium cadmium-based photopolymerization initiators may also be included as (B) photopolymerization initiators. Examples include: 2-methyl-1-[4-(methylthio)phenyl]-2-morphofolinyl-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morphofolinylphenyl)-but-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morphofolinyl)phenyl]-1-butanone, N,N-dimethylaminoacetophenone, and other α-aminoacetophenone-based photopolymerization initiators; 1-hydroxy-cyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-prop-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-prop-1-one, 2-hydroxy-2-methyl-1-phenylprop-1-one and other hydroxyacetophenone-based photopolymerization initiators; benzoin, benzoyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether and other benzoin-based photopolymerization initiators; benzoin alkyl ether-based photopolymerization initiators; diphenyl ketone, p-methyl diphenyl ketone, milchnerone, methyl diphenyl ketone, 4,4'-dichlorodiphenyl ketone Photoinitiators based on diphenyl ketones, such as 4,4'-bis(diethylamino)diphenyl ketone; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, and 2-methyl-1-[4-(methylthio)phenyl]-2-morphofolinyl-1-propanone; thioxanone, 2-ethylthioxanone, 2-isopropylthioxanone, 2,4-dimethylthioxanone, 2,4-diethylthioxanone, 2-chlorothioxanone, and 2,4-diisopropylthioxanone; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, etc. Anthraquinone-based photopolymerization initiators such as 2-ethylanthraquinone, 2-trimethylbutylanthraquinone, 1-chloroanthraquinone, 2-pentanthraquinone, and 2-aminoanthraquinone; ketal-based photopolymerization initiators such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzoate-based photopolymerization initiators such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethylbenzoate, and ethyl p-dimethylbenzoate; and oxime-based photopolymerization initiators such as 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyl oxime)], acetophenone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-, and 1-(O-acetyl oxime).

[0045] The amount of photopolymerization initiator (B) in the photosensitive resin composition, in terms of solid content, is preferably 1 to 50 parts by weight, more preferably 1 to 20 parts by weight, relative to 100 parts by weight of alkali-soluble resin (A). This improves the curability of deeper layers.

[0046] <(C) Sensitizer> The photosensitive resin composition of the present invention includes an anthracene-based sensitizer as (C) sensitizer for use with the aforementioned specific photopolymerization initiator. In addition to containing acylphosphine oxide-based and titanium thiocyanate-based photopolymerization initiators, it also contains an anthracene-based sensitizer. Therefore, the curing efficiency due to light irradiation during exposure is high, and even when the photosensitive resin composition contains 50-90% by mass of inorganic fillers having a predetermined average particle size, excellent resolution can be achieved. Furthermore, a cured product with sufficient hardness can be formed throughout the solder resist layer.

[0047] Anthracene-based sensitizers are preferably anthracene compounds represented by the following general formula: [Chemical Formula 1] .

[0048] In the above formula, A represents a single bond or an alkyl group having 1 to 20 carbon atoms, which can also be branched by alkyl groups. R represents an alkyl group having 1 to 20 carbon atoms, which can also be branched by alkyl groups, and can be a cycloalkyl group, a cycloalkylalkyl group, or be substituted with a hydroxyl group, or have some carbon atoms substituted with oxygen atoms (except in the case of forming peroxides). P and Q can be the same or different, representing hydrogen atoms, alkyl groups having 1 to 8 carbon atoms, or halogen atoms.

[0049] In the above formula, examples of alkyl groups with 1 to 20 carbon atoms, represented by A, include: methylene, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, decadecyl, hexadecyl, heptadecanyl, octadecyl, nonadecanyl, and icosyl. Alkyl groups can also be branched by alkyl groups.

[0050] Furthermore, in the above formulas, examples of alkyl groups with 1 to 8 carbon atoms, represented by P or Q, include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, etc. Additionally, examples of halogen atoms include: fluorine, chlorine, bromine, iodine, etc.

[0051] In the above formula, examples of alkyl groups with 1 to 20 carbon atoms represented by R include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tributyl, n-pentyl, isopentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecanyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecanyl, n-eicosyl, etc. Examples of groups that replace these alkyl groups with hydroxyl groups include: 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 2-hydroxybutyl, 3-hydroxybutyl, 4-hydroxybutyl, 5-hydroxypentyl, 6-hydroxyhexyl, 7-hydroxyheptyl, 8-hydroxyoctyl, 6-hydroxy-2-ethylhexyl, 9-hydroxynonyl, 10-hydroxydecyl, 11-hydroxyundecyl, 12-hydroxydodecyl, 2-hydroxy-3-methoxypropyl, 2-hydroxy-3-ethoxypropyl, 2-hydroxy-3-propoxypropyl, 2-hydroxy-3-butoxypropyl, 2-hydroxy-3-pentyloxypropyl, 2-hydroxy-3-hexyloxypropyl, 2-hydroxy-3-octyloxypropyl, 2-hydroxy-3-(2-ethylhexyloxy)propyl, 2,3-dihydroxypropyl, 2-hydroxy-3-allyloxypropyl, 2-hydroxy-3-methylallyloxypropyl, etc. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, nordimethyl, adamantyl, 4-dodecylcyclohexyl, decahydronaphthyl, and hydroxycyclohexyl. Examples of cycloalkyl groups include cyclopropylmethyl, cyclobutylmethyl, cyclopentylmethyl, cyclohexylmethyl, cycloheptylmethyl, cyclooctylmethyl, cyclononylmethyl, cyclodecylmethyl, 2-cyclobutylethyl, 2-cyclopentylethyl, 2-cyclohexylethyl, 2-cycloheptylethyl, 2-cyclooctylethyl, 2-cyclononylethyl, 2-cyclodecylethyl, 3-cyclobutylpropyl, 3-cyclopentylpropyl, 3-cyclohexylpropyl, 3-cycloheptylpropyl, 3-cyclooctylpropyl, 3-cyclononylpropyl, 3-cyclodecylpropyl, 4-cyclobutylbutyl, 4-cyclopentylbutyl, 4-cyclohexylbutyl, 4-cycloheptylbutyl, 4-cyclooctylbutyl, 4-cyclononylbutyl, 4-cyclodecylbutyl, 3-adamantylpropyl, decahydronaphthylpropyl, etc.

[0052] Among the aforementioned substances, considering ease of manufacture, availability of raw materials, and ease of handling, it is preferable that R in the above general formula is an alkyl group with 1 to 20 carbon atoms that does not contain oxygen atoms. Furthermore, A in the above general formula is preferably a single bond or a methylene group with 1 carbon atom. Taking into account various physical properties such as migration and hydrophobicity, it is preferable that R is an alkyl group with 3 or more carbon atoms. From this viewpoint, it is particularly preferable to use an anthracene-based sensitizer as shown in formula (1-a) or (1-b): [Chemical Formula 2] .

[0053] Anthracene-based sensitizers can be commercially available, such as UVS-581, UVS-1101, and UVS-1331 manufactured by Avote High Energy Chemical Co., Ltd.

[0054] (C) The sensitizer is preferably contained in a proportion of 2 to 18% by weight relative to (B) the photopolymerization initiator, more preferably in a proportion of 5 to 15%.

[0055] <(D) Inorganic packing> The photosensitive resin composition of the present invention comprises (D) inorganic filler. By incorporating inorganic filler into the photosensitive resin composition, the physical strength, etc., of the cured photosensitive resin composition, i.e., the solder resist layer, can be improved. Furthermore, from the viewpoint of improving the physical strength of the solder resist layer, the photosensitive resin composition of the present invention comprises (D) inorganic filler in a proportion of 50 to 90% by mass relative to the total solid content of the photosensitive resin composition. More preferably, the incorporation ratio is 60 to 90% by mass.

[0056] Furthermore, from the viewpoints of resolution, deep curing properties, peelability, and residue, (D) inorganic fillers using materials with an average particle size (D50) of 0.1 to 1.0 µm are preferred. If the inorganic filler has a D50 of less than 0.1 µm, it may sometimes remain on the pretreated copper-plated plate after development. Also, the photosensitive resin composition may sometimes become viscous, leading to poor coatability. On the other hand, if the inorganic filler has a D50 greater than 1.0 µm, resolution and deep curing properties may sometimes deteriorate. Furthermore, when the photosensitive resin composition is coated onto the substrate to form a cured product, adhesion to the substrate may sometimes deteriorate. The preferred average particle size of the inorganic filler is 0.4 to 0.8 µm. Furthermore, the average particle size refers to the particle size of the cumulative 50% volume obtained using a laser diffraction scattering particle size distribution measurement method. Additionally, the average particle size of silica refers to the value of silica obtained by measuring as described above before preparing the photosensitive resin composition (pre-stirring, kneading).

[0057] As (D) inorganic fillers, existing and well-known inorganic fillers can be used, such as: silica, talc, mica, alumina, calcium oxide, magnesium oxide, zinc oxide, calcium carbonate, magnesium carbonate, fly ash, dewatered sludge, kaolin, clay, calcium hydroxide, aluminum hydroxide, magnesium hydroxide, hydrotalcite, aluminum silicate, magnesium silicate, calcium silicate, wollastonite, potassium titanate, magnesium sulfate, calcium sulfate, magnesium phosphate, sepiolite, calcium silicate, boron nitride, aluminum borate, silica microspheres, glass flakes, glass microspheres, ironmaking slag, copper, iron, iron oxide, iron-silicon-aluminum soft magnetic alloy, AlNiCo magnets, various ferrite magnetic powders, cement, glass powder, Neuburg silica, diatomaceous earth, antimony trioxide, magnesium oxysulfate, hydrated aluminum, hydrated gypsum, alum, and barium sulfate, etc. One type of inorganic filler can be used alone, or two or more can be used in combination. From the viewpoint that the coefficient of thermal expansion of the cured photosensitive resin composition can be reduced, silica is preferred among the above-mentioned substances.

[0058] From the viewpoint of dispersibility, when using silica as an inorganic filler, surface treatment with a silane coupling agent is preferred. In this case, surface treatment with one of the following two types of silane coupling agents is preferred: a silane coupling agent without reactive functional groups; and a silane coupling agent having at least one reactive functional group selected from the group consisting of vinyl, (meth)acryloyl, and styrene groups. As described above, by using silica surface-treated with two types of silane coupling agents—a silane coupling agent without reactive functional groups and a silane coupling agent having specific reactive functional groups—a photosensitive resin composition that can suppress the decrease in coating properties such as elastic modulus and exhibit excellent storage stability can be obtained.

[0059] Examples of silane coupling agents that do not possess reactive functional groups include silicon-containing compounds with alkoxysilyl or silanol groups, such as: methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isopropyltrimethoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, n-pentyltrimethoxysilane, cyclopentyltrimethoxysilane, n-hexyltrimethoxysilane, cyclohexyltrimethoxysilane, n-octyltrimethoxysilane, isooctyltrimethoxysilane, n-decyltrimethoxysilane, n-dodecyltrimethoxysilane, n-tetradecyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, and vinyltrimethoxysilane. Silanes, allyltrimethoxysilane, 7-octenyltrimethoxysilane, phenyltrimethoxysilane, benzyltrimethoxysilane, 1-naphthyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, n-propyltriethoxysilane, isopropyltriethoxysilane, n-butyltriethoxysilane, isobutyltriethoxysilane, n-pentyltriethoxysilane, cyclopentyltriethoxysilane, n-hexyltriethoxysilane, cyclohexyltriethoxysilane, n-octyltriethoxysilane, isooctyltriethoxysilane, n-decyltriethoxysilane, n-dodecyltriethoxysilane, n-tetradecyltriethoxysilane, n-hexadecyltriethoxysilane, n-octadecyltriethoxysilane, etc. These silane coupling agents, which do not possess reactive functional groups, can be used alone or in combination of two or more. Among them, methyltrimethoxysilane and ethyltrimethoxysilane are preferred.

[0060] Examples of silane coupling agents with reactive functional groups include vinyl-containing silane coupling agents, (meth)acryloyl-containing silane coupling agents, and styrene-containing silane coupling agents. These can be used individually or in combination of two or more.

[0061] Examples of vinyl-containing silane coupling agents include: vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane, octenyltrimethoxysilane, allyltrimethoxysilane, etc.

[0062] Additionally, examples of silane coupling agents containing (meth)acrylyl groups include: 1,3-bis(acryloyloxymethyl)-1,1,3,3-tetramethyldisilazane, 1,3-bis(methacryloyloxymethyl)-1,1,3,3-tetramethyldisilazane, 1,3-bis(γ-acryloyloxypropyl)-1,1,3,3-tetramethyldisilazane, 1,3-bis(γ-methacryloyloxypropyl)-1,1,3,3-tetramethyldisilazane, acryloyloxymethylmethyltrisilazane, methacryloyloxymethylmethyltrisilazane, acryloyloxymethylmethyltetrasilazane, methyl Acryloyloxymethyl methyl tetrasilazane, acryloyloxymethyl methyl polysilazane, methacryloyloxymethyl methyl polysilazane, 3-acryloyloxypropyl methyl trisilazane, 3-methacryloyloxypropyl methyl trisilazane, 3-acryloyloxypropyl methyl tetrasilazane, 3-methacryloyloxypropyl methyl tetrasilazane, 3-acryloyloxypropyl methyl polysilazane, 3-methacryloyloxypropyl methyl polysilazane, acryloyloxymethyl polysilazane, methacryloyloxymethyl polysilazane, 3-acryloyloxypropyl polysilazane, 3-methacryloyloxypropyl polysilazane, etc.

[0063] In addition, examples of styrene-containing silane coupling agents include p-styrenetrimethoxysilane.

[0064] Among the silane coupling agents with reactive functional groups mentioned above, silane coupling agents containing (meth)acryloyl groups can be used, for example, methacryloyloxypropyltrimethoxysilane is preferred.

[0065] Surface treatment of silica is preferably performed by adding a silane coupling agent at a ratio of 0.5 to 10 parts by mass relative to 100 parts by mass of silica, more preferably at a ratio of 0.5 to 2.0 parts by mass. Surface treatment of silica can be performed by first preparing a dispersion in a suitable solvent, then adding a predetermined amount of silane coupling agent to the silica dispersion and stirring, thereby performing surface treatment. To promote the surface treatment reaction, stirring can also be performed under a heating environment at a temperature of 50 to 100°C.

[0066] Regarding silica, in the silane coupling agent coated on the silica surface, the amount of the silane coupling agent having reactive functional groups coated is preferably greater than the amount of the silane coupling agent without reactive functional groups coated. Silanes with this coating ratio can be obtained by surface treatment of silica, for example, by adjusting the mixing amount of the two when adding the silane coupling agent to the silica dispersion, thereby making the amount of the silane coupling agent with reactive functional groups greater than that without reactive functional groups, thus obtaining silanes. Particularly preferred silica is silica in which the ratio of the amount of silane coupling agent with reactive functional groups coated to the amount of silane coupling agent without reactive functional groups coated is 2:1 to 10:1 by mass. Silica with this coating ratio can be obtained, for example, by surface treatment of the silica using a silane coupling agent comprising a silane coupling agent with reactive functional groups and a silane coupling agent without reactive functional groups in a mass ratio of 2:1 to 10:1. Whether or not surface treatment is performed can be confirmed by quantifying the free unreacted coupling agent in the silica slurry using LC-MS. Furthermore, the added silane coupling agent can coat approximately 60-90% of the silica.

[0067] In addition, compared to the case where silica and silane coupling agent are placed separately, surface-treated silica can achieve better results.

[0068] The silica used for surface treatment can be any known material without limitation, and can be either amorphous or crystalline, or a mixture thereof. Amorphous (molten) silica is particularly preferred.

[0069] <(E) Photopolymerizable monomers> The photosensitive resin composition of the present invention comprises (E) a photopolymerizable monomer. The photopolymerizable monomer is a monomer having an vinyl unsaturated double bond. Examples of such photopolymerizable monomers include, for instance, conventionally known polyester (meth)acrylates, polyether (meth)acrylates, urethane (meth)acrylates, carbonate (meth)acrylates, epoxy (meth)acrylates, etc. Specifically, this includes alkyl acrylates such as 2-ethylhexyl acrylate and cyclohexyl acrylate; hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; monoacrylates or diacrylates of epoxide derivatives such as ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol; acrylamides such as N,N-dimethylacrylamide, N-hydroxymethylacrylamide, and N,N-dimethylaminopropylacrylamide; aminoalkyl acrylates such as N,N-dimethylaminoethyl acrylate and N,N-dimethylaminopropyl acrylate; and epoxides derived from polyols or such epoxides, such as hexanediol, trimethylolpropane, neopentyl terephthalate, di-trimethylolpropane, di-neopentyl terephthalate, and trimethylolpropane. Polyacrylates such as esters or ε-caprolactone adducts; polyacrylates such as phenolic compounds or their epoxy alkyl adducts, such as phenoxy acrylates and bisphenol A diacrylates; acrylates derived from glycidyl ethers such as glycerol diglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl triisocyanate; and not limited to the above substances, at least one of the following substances may be appropriately selected for use: acrylates obtained by direct acrylate esterification of polyether polyols, polycarbonate diols, hydroxyl-terminated polybutadiene, polyester polyols, etc., or by acrylate acrylate esterification of diisocyanates, as well as melamine acrylates, and various methacrylates corresponding to the acrylates. This photopolymerizable monomer can also be used as a reactive diluent.

[0070] (E) Photopolymerizable monomers can be used alone or in combination of two or more. The amount of photopolymerizable monomer mixed with (A) 100 parts by weight of alkali-soluble resin, converted to solids content, is preferably 0.5 to 30 parts by weight. If the mixing amount is 0.5 parts by weight or more, photocurability is good, and patterns are easily formed in alkaline development after irradiation with activation energy rays. Furthermore, if the mixing amount is 30 parts by weight or less, haloing is less likely to occur, resulting in good resolution.

[0071] <(F) Thermosetting components> In addition to the components described above, the photosensitive resin composition of the present invention may also include (F) a thermosetting component. Examples of thermosetting components include isocyanate compounds, terminal isocyanate compounds, amino resins, maleimide compounds, benzoxazine resins, carbodiimide resins, cyclic carbonate compounds, epoxy compounds, oxetane compounds, cyclic sulfide resins, and other commonly known substances. Among these substances, epoxy resin is preferred as the thermosetting component.

[0072] Examples of epoxy resins include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol S type epoxy resin, phenolic varnish type epoxy resin, cresol phenolic varnish type epoxy resin, bisphenol A phenolic varnish type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin, etc. They can be used alone or in combination of two or more.

[0073] Commercially available epoxy resins include, for example: jER 828, 806, 807, YX8000, YX8034, and 834 manufactured by Mitsubishi Chemical Corporation; YD-128, YDF-170, ZX-1059, and ST-3000 manufactured by Nippon Steel Chemical Materials Co., Ltd.; EPICLON 830, 835, 840, 850, N-730A, and N-695 manufactured by DISCO; and RE-306 manufactured by Nippon Kayaku Co., Ltd.

[0074] The epoxy group equivalent of the epoxy resin in the photosensitive resin composition, calculated in terms of solid content, is preferably 0.5 to 2.5, relative to the carboxyl group equivalent of the carboxyl-containing resin. By setting the amount to 0.5 equivalents or more, residual carboxyl groups in the cured product can be prevented, and good heat resistance, alkali resistance, and electrical insulation properties can be obtained. Furthermore, by setting the above-mentioned blending amount to 2.5 equivalents or less, low molecular weight cyclic (thio)ether groups can be prevented from remaining in the dried coating film, and good strength and other properties of the cured product can be ensured.

[0075] When the photosensitive resin composition of the present invention contains a thermosetting component, it may include a thermosetting catalyst for promoting the curing of the thermosetting component. Examples of thermosetting catalysts include: imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; amine compounds such as dicyandiamine, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, and 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipate dihydrazide and sebacate dihydrazide; and phosphorus compounds such as triphenylphosphine. In addition, commercially available products include, for example, 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, and 2P4MHZ (all trade names of imidazole compounds) manufactured by Shikoku Chemical Industry Co., Ltd., and U-CAT 3513N (trade name of dimethylamine compound), DBU, DBN, and U-CAT SA 102 (all bicyclic amidine compounds and their salts) manufactured by Miya Pro Co., Ltd.

[0076] The compounds are not limited to those mentioned above; any thermosetting catalyst that is an epoxy resin, an oxetane compound, or a substance that can promote the reaction of at least one of the epoxy group and the oxetane group with the carboxyl group is acceptable. They can be used alone or in combination of two or more. Additionally, S-triazine derivatives such as guanidine, acetylguanidine, benzoguanidine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine isocyanuric acid adduct, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine isocyanuric acid adduct are also acceptable. Preferably, such compounds, which can also function as adhesive agents, are used together with the thermosetting catalyst.

[0077] The thermosetting catalyst can be used alone or in combination of two or more. From the viewpoint of the storage stability of the resin composition and the heat resistance of the cured coating (i.e., the coating composed of the cured material), the amount of thermosetting catalyst mixed in, in terms of solid content, is preferably 0.01 to 30 parts by weight, more preferably 0.1 to 20 parts by weight, relative to 100 parts by weight of alkali-soluble resin (A).

[0078] <Other Ingredients> In addition to the above-mentioned components, the photosensitive resin composition of the present invention may also be mixed with, as needed, colorants, elastomers, mercapto compounds, urethane esterification catalysts, thixotropic agents, adhesion promoters, block copolymers, chain transfer agents, polymerization inhibitors, copper corrosion inhibitors, antioxidants, rust inhibitors, organobenzene, montmorillonite and other thickeners, at least one of polysiloxane-based, fluorine-based, polymer-based defoamers and leveling agents, phosphonates, phosphate ester derivatives, phosphazene compounds and other phosphorus compounds and other flame retardants. These can be substances known in the field of electronic materials.

[0079] From the viewpoint of ease of preparation and coatability, organic solvents can also be incorporated into the photosensitive resin composition of the present invention. The following commonly known organic solvents can be used: ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellulose, methyl cellulose, butyl cellulose, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, diethylene glycol monomethyl ether acetate, and tripropylene glycol monomethyl ether; esters such as ethyl acetate, butyl acetate, butyl lactate, cellulose acetate, butyl cellulose acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, naphtha, and solvent naphtha. One or more of these organic solvents can be used alone or in combination.

[0080] The amount of organic solvent in the photosensitive resin composition can be appropriately changed according to the materials constituting the photosensitive resin composition.

[0081] The photosensitive resin composition of the present invention can be used in dry film form or in liquid form. Furthermore, when used in liquid form, it can be a single-component or a two-component or more-component composition.

[0082] <Dry film> The photosensitive resin composition of the present invention can also be formulated as a dry film having a first film and a resin layer, wherein the resin layer is formed on the first film and is composed of the aforementioned photosensitive resin composition. The first film in the dry film of the present invention refers to a film that is at least adhered to the resin layer when integrally formed by lamination, such as by heating, with the resin layer side of the photosensitive resin composition already formed on the dry film in contact with a substrate such as a substrate. The first film can also be peeled off from the resin layer in a post-lamination step. In the present invention, it is particularly preferable to peel it off from the resin layer in a post-exposure step.

[0083] When preparing the dry film, the photosensitive resin composition of the present invention can be diluted with an organic solvent to adjust to a suitable viscosity, and then coated onto a first film to a uniform thickness using a notched roller coater, doctor blade coater, lip coater, bar coater, extrusion coater, reverse coater, transfer roller coater, gravure coater, or spray coater. The film is typically dried at a temperature of 50–130°C for 1–30 minutes to obtain the final film. There are no particular limitations on the film thickness, but the dried film thickness is generally within the range of 1–150 µm, preferably within the range of 5–60 µm.

[0084] As the first membrane, any known material can be used without particular limitation. For example, films made of thermoplastic resins such as polyethylene terephthalate (PET) or polyethylene naphthalate (PET), polyimide films, polyamide-imide films, polypropylene films, and polystyrene films are preferred. From the viewpoints of heat resistance, mechanical strength, and processability, polyester films are preferred among these. Furthermore, laminates of such films can also be used as the first membrane.

[0085] Furthermore, from the viewpoint of improving mechanical strength, the aforementioned thermoplastic resin film is preferably a film that extends along a uniaxial direction or a biaxial direction.

[0086] There is no particular limitation on the thickness of the first membrane, but it can be set to, for example, 10µm to 150µm.

[0087] After the resin layer of the photosensitive resin composition of the present invention is formed on the first film, in order to prevent dust from adhering to the surface of the resin layer, it is preferable to laminate a peelable second film on the surface of the resin layer. The second film in the dry film of the present invention refers to a film that is peeled off from the resin layer before lamination when the dry film is integrally formed by lamination by heating or the like, so that the resin layer side of the dry film is in contact with a substrate such as a substrate.

[0088] The second film that can be peeled off from the resin layer can be, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, or a surface-treated paper, as long as the adhesive force between the resin layer and the second film is less than the adhesive force between the resin layer and the first film when peeling off the second film.

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

[0090] <Cured product> The cured product of the present invention is obtained by curing the above-mentioned photosensitive resin composition or the resin layer of the above-mentioned dry film.

[0091] Printed wiring boards The printed wiring board of the present invention has a cured product obtained from the resin layer of the photosensitive resin composition or dry film of the present invention. As a method for manufacturing the printed wiring board of the present invention, for example, the photosensitive resin composition of the present invention is adjusted to a viscosity suitable for a coating method using the aforementioned organic solvent, and then coated onto a substrate by methods such as dip coating, flow coating, roller coating, bar coating, screen printing, or curtain coating. Afterwards, the organic solvent contained in the composition is evaporated and dried (temporarily dried) at a temperature of 60-100°C, thereby forming a non-sticky resin layer. Alternatively, in the case of a dry film, the resin layer is bonded to the substrate in contact with the substrate by lamination or the like, thereby forming a resin layer on the substrate.

[0092] In addition to printed wiring boards or flexible printed wiring boards with circuits pre-formed on copper, the aforementioned substrates also include copper-clad laminates of all grades (FR-4, etc.) using materials such as phenolic paper, epoxy paper, epoxy glass cloth, polyimide glass, epoxy glass cloth / non-woven fabric, epoxy glass cloth / paper, epoxy synthetic fiber, fluoropolymer / polyethylene / polyphenylene ether, and polyoxyphenylene oxide / cyanate for high-frequency circuits. Other substrates include metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, and wafer boards.

[0093] When the film is in dry film form, it is preferable to laminate it onto the substrate under pressure and heat using a vacuum laminator or similar equipment. By using a vacuum laminator, even if the surface of the circuit board has unevenness, the dry film will still adhere to the circuit board, thus preventing air bubbles from entering and improving the filling effect of the recesses on the substrate surface. The pressure conditions are preferably around 0.1 to 2.0 MPa, and the heating conditions are preferably 40 to 120°C.

[0094] When the photosensitive resin composition of the present invention contains an organic solvent, it is preferable to coat the surface of the substrate with the photosensitive resin composition and then perform evaporation drying. Evaporation drying can be performed using a hot air circulating drying oven, IR oven, heating plate, convection oven, etc. (methods that use a heat source with a heat source that utilizes steam to heat the air and make hot air in the dryer convect and contact, and methods that blow the material onto the substrate through a nozzle).

[0095] After forming a resin layer on a substrate, a photomask with a predetermined pattern is selectively exposed to activation energy rays. The unexposed areas are then developed using a dilute alkaline aqueous solution (e.g., 0.3-3% by mass sodium carbonate aqueous solution) to form a patterned cured product. In the case of a dry film, the first film is peeled off from the dry film after exposure and developed, thereby forming a patterned cured product on the substrate. Furthermore, in the case of a dry film, if the properties are not compromised, the first film can be peeled off from the dry film before exposure, and then the exposed resin layer can be exposed and developed. Moreover, by irradiating the cured product with activation energy rays followed by heat curing (e.g., 100-220°C), or by irradiating the cured product with activation energy rays after heat curing, or by performing final fine curing (formal curing) solely with heat curing, a cured coating with excellent adhesion, hardness, and other properties can be formed.

[0096] The exposure machine used for the aforementioned activation energy ray irradiation only needs to be a device equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, or a mercury short-arc lamp, capable of irradiating ultraviolet light in the range of 350-450 nm. Alternatively, a direct drawing device (e.g., a laser direct imaging device that directly draws images using lasers based on CAD data from a computer) can also be used. The light source or laser source of the direct drawing machine can be a light source with a maximum wavelength in the range of 350-450 nm. The exposure amount used to form the image varies depending on the film thickness, and is generally set to 10-1000 mJ / cm². 2 Within the range of 20~800mJ / cm, it is preferably set to 20~800mJ / cm 2 Within the range.

[0097] The above-mentioned developing methods can utilize immersion, spraying, spraying, brushing, etc., and the developing solution can be an alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, or amines.

[0098] After a cured coating is formed on the substrate as described above, electronic components and other parts are mounted onto the substrate via solder reflow. Solder reflow can be performed using existing known methods. Furthermore, solder reflow is generally performed under processing conditions, for example, at 245–260°C for 5–10 seconds.

[0099] The photosensitive resin composition or dry film of the present invention is suitable for use in the manufacture of electronic components such as printed wiring boards, and is even more suitable for forming permanent coatings. In this case, a cured product is formed using the photosensitive resin composition or dry film of the present invention through the methods described above. When the resin layer of the photosensitive resin composition or dry film of the present invention is insulating, it is suitable for forming solder resist films, cover layers, or interlayer insulating layers. It is particularly suitable for use in forming permanent coatings such as solder resist films that can be used in packaging substrates. Furthermore, the photosensitive resin composition of the present invention can also be used to form solder dams.

[0100] Example Next, embodiments will be provided to further illustrate the invention in detail, but the invention is not limited to these embodiments. Furthermore, unless otherwise specified, "parts" and "%" refer to mass measurements.

[0101] <Synthesis Example 1 (Synthesis of Alkali-Soluble Resin A)> In a high-pressure autoclave equipped with a thermometer, a nitrogen introduction device, an epoxy alkane introduction device, and a stirring device, 119.4 parts by weight of phenolic varnish-type cresol resin (trade name "Shonol CRG951", manufactured by Aike Industrial Co., Ltd., OH equivalent: 119.4), 1.19 parts by weight of potassium hydroxide, and 119.4 parts by weight of toluene were introduced. While stirring, nitrogen replacement and heating were carried out in the system. Then, 63.8 parts by weight of propylene oxide were slowly added dropwise at 125~132℃ and 0~4.8 kg / cm³. 2 The reaction was carried out under the specified conditions for 16 hours. Afterwards, the solution was cooled to room temperature, and 1.56 parts by mass of 89% phosphoric acid was added and mixed into the reaction solution while potassium hydroxide was neutralized to obtain a propylene oxide reaction solution of phenolic varnish-type cresol resin [solid content: 62.1%; hydroxyl value: 182.2 mg KOH / g (307.9 g / eq.)]. This propylene oxide reaction solution contained an average of 1.08 moles of propylene oxide added per phenolic hydroxyl group.

[0102] 293.0 parts by mass of the obtained propylene oxide reaction solution of phenolic varnish-type cresol resin, 43.2 parts by mass of acrylic acid, 11.53 parts by mass of methanesulfonic acid, 0.18 parts by mass of hydroquinone, and 252.9 parts by mass of toluene were introduced into a reactor equipped with a stirrer, thermometer, and air blow-in pipe. Air was blown in at a rate of 10 ml / min, and the reaction was carried out at 110°C for 12 hours with stirring. 12.6 parts by mass of water generated in the reaction was distilled off as an azeotropic mixture with toluene. Afterward, the mixture was cooled to room temperature and neutralized with 35.35 parts by mass of 15% sodium hydroxide aqueous solution, followed by washing with water. Then, the mixture was distilled off in a still while replacing toluene with 118.1 parts by mass of propylene glycol monomethyl ether acetate (PMA) to obtain a phenolic varnish-type acrylate resin solution. Next, 332.5 parts by weight of the obtained phenolic varnish-type acrylate resin solution and 1.22 parts by weight of triphenylphosphine were introduced into a reactor equipped with a stirrer, thermometer, and air blow-in pipe. Air was blown in at a rate of 10 ml / min, and 60.8 parts by weight of tetrahydrophthalic anhydride were slowly added while stirring. The reaction was carried out at 95-101°C for 6 hours, and then cooled and removed. In this way, a solution of alkali-soluble resin A was obtained (solid content: 65% by weight, acid value of solid content: 87.7 mg KOH / g).

[0103] <Preparation of Inorganic Fillers> [Silicon dioxide 1] A pre-dispersion was prepared by adding 70g of spherical silica (ADMAFINESO-C2, manufactured by Yaduma Co., Ltd., with an average particle size of 0.5µm) to 30g of propylene glycol monomethyl ether acetate (PMA) as a solvent and stirring. Next, 0.8g of methacryloxypropyltrimethoxysilane (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.1g of methyltrimethoxysilane (KBM-13, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to the pre-dispersion, and the mixture was stirred at 50°C to obtain a silica slurry (70% by mass of silica solids) surface-treated with two silane coupling agents.

[0104] [Silicon dioxide 2] A pre-dispersion was prepared by adding 70g of spherical silica (ADMAFINESO-C1, manufactured by Yaduma Co., Ltd., with an average particle size of 0.3µm) to 30g of propylene glycol monomethyl ether acetate (PMA) as a solvent and stirring. Next, 0.8g of methacryloxypropyltrimethoxysilane (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.1g of methyltrimethoxysilane (KBM-13, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to the pre-dispersion, and the mixture was stirred at 50°C to obtain a silica slurry (70% by mass of silica solids) surface-treated with two silane coupling agents.

[0105] [Silicon dioxide 3] A pre-dispersion was prepared by adding 70g of spherical silica (ADMAFINESO-C4, manufactured by Yaduma Co., Ltd., with an average particle size of 1.2µm) to 30g of propylene glycol monomethyl ether acetate (PMA) as a solvent and stirring. Next, 0.8g of methacryloxypropyltrimethoxysilane (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.1g of methyltrimethoxysilane (KBM-13, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to the pre-dispersion, and the mixture was stirred at 50°C to obtain a silica slurry (70% by mass of silica solids) surface-treated with two silane coupling agents.

[0106] [Silicon dioxide 4] A pre-dispersion was prepared by adding 70g of spherical silica (ADMANANOYA050C, manufactured by Yaduma Co., Ltd., with an average particle size of 0.05µm) to 30g of propylene glycol monomethyl ether acetate (PMA) as a solvent and stirring. Next, 0.8g of methacryloxypropyltrimethoxysilane (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.1g of methyltrimethoxysilane (KBM-13, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to the pre-dispersion, and the mixture was stirred at 50°C to obtain a silica slurry (70% by mass of silica solids) surface-treated with two silane coupling agents.

[0107] <Preparation of Photosensitive Resin Compositions> The components listed in Table 1 below are blended and mixed using a three-roll mill at room temperature to obtain the photosensitive resin compositions listed in the table. Furthermore, the values ​​in the table represent parts by mass (including the mass of the solvent).

[0108] Furthermore, the components *1 to *6 in Table 1 below are as described below.

[0109] *1: Acylphosphine oxide-based photopolymerization initiator (2,4,6-trimethylbenzoyldiphenylphosphine oxide); *2: Titanium thiocyanate photopolymerization initiator (manufactured by Yueyang Jinmaotai Technology Co., Ltd.); *3: Anthracene-based sensitizer (manufactured by Aiwote High Energy Chemical Co., Ltd.); *4: Anthracene-based sensitizer (manufactured by Aiwote High Energy Chemical Co., Ltd.); *5: Dinepentylenetetraol hexaacrylate; *6: Bisphenol A type epoxy resin (solvent-reduced product manufactured by D.E. Co., Ltd., solid content: 85% by weight); *7: Blue and yellow pigments; *8: Propylene glycol monomethyl ether acetate (PMA).

[0110] <Resolution Evaluation> The photosensitive resin compositions obtained as described above were applied to the surface of a polyethylene terephthalate film (T-60, manufactured by Toray Industries, Inc., 38µm thick) using a smearer, and dried at 80°C for 20 minutes to produce a dry film with a resin layer thickness of 25µm. Next, the dry film was laminated onto a BT substrate using a vacuum laminator (CVP-600, manufactured by Nikko Materials Co., Ltd.), thereby forming a resin layer on the substrate. Subsequently, a DI exposure apparatus equipped with a high-pressure mercury lamp (manufactured by Oulsi Manufacturing Co., Ltd.) was used to pattern the resin layer side of the substrate at the optimal exposure level with a linewidth and spacing (L / S) of 100µm / 100µm. The optimal exposure was as follows: the resin layer obtained above was exposed using a DI exposure apparatus with a 21-segment exposure meter, and then developed for 60 seconds using a 1% by mass Na₂CO₃ aqueous solution at 30°C and a spray pressure of 0.2 MPa. At this point, the remaining pattern on the exposure meter showed an exposure of 9 segments. Next, development was performed using a 1% by mass Na₂CO₃ aqueous solution at 30°C, followed by rinsing with water. Afterward, the sample was cured at 170°C for 60 minutes to produce an evaluation sample.

[0111] The evaluation samples were sealed and cured using cold-embedded resin (105NSP, manufactured by Stell Corporation), and then the resulting samples were cut and the cross-sections were observed using an electron microscope (×1000x). Figure 1 This is a schematic diagram of the cross-section. In the cross-sectional view of the cured coating, let the widest point be W. Max (µm) and let the narrowest point be W. MIN (µm), and the difference between them is used as an indicator to evaluate the resolution according to the following evaluation criteria.

[0112] ○:W MAX -WMin The difference is less than 10µm; △:W MAX -W Min The difference is greater than 10µm but less than 16µm; ×:W MAX -W Min The difference is greater than 16µm, or it cannot be formed; The evaluation results are shown in Table 1 below.

[0113] <Gloss> In the <Resolution Evaluation>, a copper-plated board pretreated with MAG Corporation's CZ-8100 was used, and the exposure was set to 200 mJ / cm². 2 Otherwise, prepare evaluation samples in the same manner as described above. Evaluate the gloss at this time according to the evaluation criteria below.

[0114] ○: 7 or more stanzas; △: Less than 7 dan; ×: Cannot be formed; The evaluation results are shown in Table 1 below.

[0115] <Margin> In the <Resolution Evaluation>, a copper-plated board pretreated with a CZ-8100 manufactured by Magtech Corporation was used. During exposure, the focus was shifted by +60µm from the substrate surface, and the pattern was exposed with an aperture diameter of 200µm. Otherwise, an evaluation sample was prepared in the same manner as described above. The obtained evaluation sample was observed using an optical microscope (×500x), and the top diameter of the aperture was measured.

[0116] ○: The difference between the opening diameter and the design value (200µm) is less than 1µm; ×: The difference between the opening diameter and the design value (200µm) is more than 1µm, or it cannot be formed; The evaluation results are shown in Table 1 below.

[0117] <Adhesion> In the <Resolution Evaluation>, the exposure pattern is set to a line width and spacing (L / S) of 40µm / 100µm. Otherwise, it is performed in the same manner as above. The obtained evaluation sample is peeled off twice using celluloid tape, and the cured coating remaining on the substrate side is observed using an optical microscope (×30x). The adhesion is evaluated using the following evaluation criteria.

[0118] ○: None of the threads have peeled off; ×: Some or all of the lines have peeled off, or the lines cannot be formed. The evaluation results are shown in Table 1 below.

[0119] <Evaluation of Coating Properties (Elastic Modulus)> In the <Resolution Evaluation>, copper foil was used as the substrate, and the process was otherwise carried out in the same manner as described above. An 8cm long and 1cm wide cured film was peeled off from the obtained evaluation sample, and the peeled cured film was then fed into a universal testing machine (AG-X, manufactured by Shimadzu Corporation) to measure the elastic modulus at room temperature. The evaluation criteria are as follows.

[0120] ○: Elastic modulus is above 6 GPa; ×: Elastic modulus is less than 6 GPa; The evaluation results are shown in Table 1 below.

[0121] <Identification of Residue> In the <Resolution Evaluation>, copper-plated boards pretreated with Magtech CZ-8100 were used. Otherwise, the process was the same as described above. The copper surface of the evaluation sample with an opening diameter of 200µm was observed using an electron microscope (×5000x), and the number of identifiable fillers was measured. The evaluation criteria are as follows.

[0122] ○: Less than 10; ×: More than 10; The evaluation results are shown in Table 1 below.

[0123] [Table 1]

Claims

1. A photosensitive resin composition, characterized in that, At least include: (A) Alkali-soluble resin; (B) Photopolymerization initiator; (C) Sensitizer; (D) Inorganic fillers; and (E) Photopolymerizable monomers, The photopolymerization initiator (B) includes acylphosphine oxide-based photopolymerization initiators and titanium lithocene-based photopolymerization initiators. The sensitizer (C) comprises anthracene-based sensitizers. The inorganic filler (D) is contained in the photosensitive resin composition at a ratio of 50-90% by mass relative to all solid components. The average particle size (D50) of the (D) inorganic filler is 0.1~1.0µm.

2. The photosensitive resin composition according to claim 1, wherein, The acylphosphine oxide-based photopolymerization initiator and the titanium cadmium-based photopolymerization initiator are contained in a ratio of 10:1 to 90:1 by mass.

3. The photosensitive resin composition according to claim 1, wherein, The sensitizer (C) is contained in a proportion of 2 to 18% by weight relative to the photopolymerization initiator (B).

4. The photosensitive resin composition according to claim 1, wherein, The inorganic filler (D) contains silicon dioxide.

5. The photosensitive resin composition according to claim 1, wherein, It also contains (F) thermosetting components.

6. A dry film, characterized in that, have: First membrane; and Coating one side of the first film The resin layer obtained by drying the photosensitive resin composition according to claim 1.

7. A cured product, characterized in that, It is formed by curing the photosensitive resin composition according to any one of claims 1 to 5 or the resin layer of the dry film according to claim 6.

8. A printed wiring board, characterized in that, It has a coating made of the cured material as described in claim 7.

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