Photosensitive resin composition, photosensitive element, and printed wiring board

Abstract

The present disclosure relates to a photosensitive resin composition for a permanent resist, the photosensitive resin composition containing (A) an acid-modified vinyl group-containing resin, (B) a photopolymerizable compound, (C) a photopolymerization initiator, (D) a thermosetting resin, and (E) a pigment, but not containing silica.

Description

Photosensitive resin composition, photosensitive element, and printed wiring board

[0001] The present disclosure relates to a photosensitive resin composition for permanent resist, a photosensitive element, and a printed wiring board.

[0002] As the performance of various electronic devices improves, the integration of semiconductors is becoming more and more advanced, which requires various performance features from permanent resists (e.g., solder resists) formed on printed wiring boards, semiconductor package substrates, etc.

[0003] Known photosensitive resin compositions used for forming permanent resists include, for example, photosensitive resin compositions containing an acid-modified vinyl group-containing epoxy resin, an epoxy resin, a photopolymerization initiator, a photopolymerizable compound, and an inorganic filler (see Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2021-33207

[0005] Conventional photosensitive resin compositions containing silica as an inorganic filler sometimes have difficulty in achieving sufficient resolution in via formation. The present disclosure provides a photosensitive resin composition with excellent resolution, and a photosensitive element and a printed wiring board using the same.

[0006] One aspect of the present disclosure relates to the following photosensitive resin composition, photosensitive element, and printed wiring board: [1] A photosensitive resin composition for permanent resist, containing (A) an acid-modified vinyl group-containing resin, (B) a photopolymerizable compound, (C) a photopolymerization initiator, (D) a thermosetting resin, and (E) a pigment, and not containing silica. [2] The lightness L of a 20 μm-thick resin film formed by applying the photosensitive resin composition to a substrate and drying it is ＊is less than 40. [3] The photosensitive resin composition according to [1] above, further comprising (F) an elastomer. [4] The photosensitive resin composition according to [3] above, wherein the elastomer comprises a polyester-based elastomer. [5] A photosensitive element comprising a support film and a photosensitive layer formed on the support film, the photosensitive layer comprising the photosensitive resin composition according to any one of [1] to [4] above. [6] A printed wiring board comprising a permanent resist comprising a cured product of the photosensitive resin composition according to any one of [1] to [4] above.

[0007] According to the present invention, it is possible to provide a photosensitive resin composition capable of forming a resist pattern with excellent resolution, and a photosensitive element and a printed wiring board using the photosensitive resin composition.

[0008] FIG. 1 is a cross-sectional view schematically illustrating a photosensitive element according to an embodiment of the present invention.

[0009] Hereinafter, one embodiment of the present disclosure will be specifically described, but the present disclosure is not limited thereto. In the following embodiments, the components (including element steps, etc.) are not essential unless otherwise specified, or unless they are considered to be clearly essential in principle. The same applies to numerical values ​​and their ranges, and they do not unduly limit the present disclosure.

[0010] In this disclosure, the term "layer" encompasses not only a structure with a shape formed over the entire surface when observed in a plan view, but also a structure with a shape formed on a portion of the surface. In this disclosure, the term "process" refers not only to an independent process, but also to a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. In this disclosure, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In numerical ranges described in stages in this disclosure, the upper or lower limit of a numerical range of a certain stage may be replaced with the upper or lower limit of a numerical range of another stage. Furthermore, in numerical ranges described in this disclosure, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. In this disclosure, "A or B" may include either A or B, or may include both. Unless otherwise specified, the materials exemplified below may be used alone or in combination of two or more. In the present disclosure, when a plurality of substances corresponding to each component are present in the composition, the content of each component in the composition means the total amount of the plurality of substances present in the composition, unless otherwise specified.

[0011] In the present disclosure, the term "solid content" refers to the non-volatile content excluding volatile substances such as water and diluents contained in the photosensitive resin composition, and refers to components that remain without evaporating or vaporizing when the resin composition is dried, and also includes components that are liquid, syrup-like, or waxy at room temperature (25°C; the same applies hereinafter).

[0012] [Photosensitive Resin Composition] The photosensitive resin composition for permanent resist according to this embodiment contains (A) an acid-modified vinyl group-containing resin (hereinafter also referred to as "component (A)"), (B) a photopolymerizable compound (hereinafter also referred to as "component (B)"), (C) a photopolymerization initiator (hereinafter also referred to as "component (C)"), (D) a thermosetting resin (hereinafter also referred to as "component (D)"), and (E) a pigment (hereinafter also referred to as "component (E)"), and does not contain silica. The photosensitive resin composition according to this embodiment is a negative photosensitive resin composition, and a cured film of the photosensitive resin composition can be suitably used as a permanent resist.

[0013] The photosensitive resin composition according to this embodiment contains components (A) to (E) as essential components, and does not contain silica, thereby enabling the formation of a permanent resist with excellent resolution. The photosensitive resin composition according to this embodiment is suitable for via formation by photolithography. Each component contained in the photosensitive resin composition according to this embodiment will be described in detail below.

[0014] (Component (A): Acid-Modified Vinyl Group-Containing Resin) The photosensitive resin composition according to this embodiment contains an acid-modified vinyl group-containing resin as component (A). The acid-modified vinyl group-containing resin is not particularly limited as long as it has a vinyl bond that is a photopolymerizable ethylenically unsaturated bond and an alkali-soluble acidic group. The component (A) can be used alone or in combination of two or more.

[0015] Examples of the group having an ethylenically unsaturated bond contained in component (A) include a vinyl group, an allyl group, a propargyl group, a butenyl group, an ethynyl group, a phenylethynyl group, a maleimide group, a nadimide group, and a (meth)acryloyl group. Among these, from the viewpoint of reactivity and resolution, the group having an ethylenically unsaturated bond may be a (meth)acryloyl group. Examples of the acidic group contained in component (A) include a carboxy group, a sulfo group, and a phenolic hydroxyl group. Among these, from the viewpoint of resolution, the acidic group may be a carboxy group.

[0016] The component (A) may be an acid-modified vinyl group-containing epoxy derivative obtained by reacting (a3) ​​a saturated or unsaturated group-containing polybasic acid anhydride with a resin (A') obtained by reacting (a1) an epoxy resin with (a2) an ethylenically unsaturated group-containing organic acid.

[0017] Examples of the acid-modified vinyl group-containing epoxy derivative include acid-modified epoxy (meth)acrylate, such as an addition reaction product obtained by adding a saturated or unsaturated polybasic acid anhydride to an ester obtained by reacting an epoxy resin with a vinyl group-containing monocarboxylic acid.

[0018] (a1) Examples of epoxy resins include bisphenol-type epoxy resins, novolac-type epoxy resins, biphenyl-type epoxy resins, naphthalene-type epoxy resins, and dicyclopentadiene-type epoxy resins.

[0019] Examples of bisphenol type epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, and hydrogenated bisphenol A type epoxy resins.

[0020] Examples of commercially available bisphenol-type epoxy resins include jER807, jER825, jER827, jER828, jER834, jER1004F, jER1007FS, and jER1009F (all of which are product names manufactured by Mitsubishi Chemical Corporation), D.E.R-330 and D.E.R-354 (all of which are product names manufactured by Olin Corporation), and YD-8125, YDF-170, YDF-2001, YDF-2004, and YDF-8170C (all of which are product names manufactured by Nippon Steel Chemical & Material Co., Ltd.).

[0021] Examples of novolac epoxy resins include phenol novolac epoxy resins and cresol novolac epoxy resins, which can be obtained by reacting a phenol novolac resin or a cresol novolac resin with epichlorohydrin using a known method.

[0022] Commercially available novolac epoxy resins include, for example, YDCN-700-7, YDCN-700-10, YDCN-704, YDCN-704A, and YDPN-638 (all of which are trade names manufactured by Nippon Steel Chemical & Material Co., Ltd.), D.E.N. 431, and D.E.N. 438 (all trade names, manufactured by Olin Chemical), EOCN-102S, EOCN-103S, EOCN-104S, EOCN-1012, EOCN-1027, BREN-S (all trade names, manufactured by Nippon Kayaku Co., Ltd.), EPN1138, EPN9880, ECN1299 (all trade names, manufactured by Hantsman Chemical), N-740, N-770, N-665, N-673 (all trade names, manufactured by DIC Corporation), and the like.

[0023] Examples of (a2) ethylenically unsaturated group-containing organic acids include acrylic acid derivatives such as (meth)acrylic acid, crotonic acid, cinnamic acid, and α-cyanocinnamic acid; half-ester compounds which are reaction products of hydroxyl group-containing (meth)acrylates and dibasic acid anhydrides; and half-ester compounds which are reaction products of vinyl group-containing monoglycidyl ethers or vinyl group-containing monoglycidyl esters and dibasic acid anhydrides.

[0024] The half-ester compound can be obtained, for example, by reacting a hydroxyl group-containing (meth)acrylate, a vinyl group-containing monoglycidyl ether, or a vinyl group-containing monoglycidyl ester with a dibasic acid anhydride.

[0025] Examples of hydroxyl group-containing (meth)acrylates, vinyl group-containing monoglycidyl ethers, and vinyl group-containing monoglycidyl esters include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and glycidyl (meth)acrylate.

[0026] Examples of dibasic acid anhydrides include succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, ethyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, ethylhexahydrophthalic anhydride, and itaconic anhydride.

[0027] The component (a2) may be used alone or in combination of two or more. Among these, acrylic acid is preferred.

[0028] In the reaction between component (a1) and component (a2), the ratio of component (a2) may be 0.7 to 1.05 equivalents or 0.8 to 1.0 equivalents of component (a2) per equivalent of epoxy group in component (a1). Reaction at such a ratio tends to increase photosensitivity and result in excellent linearity of the resist pattern contour.

[0029] The (a1) component and the (a2) component can be dissolved in an organic solvent and reacted. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, and carbitol acetate; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. The organic solvents may be used alone or in combination of two or more.

[0030] A catalyst may be used to promote the reaction between component (a1) and component (a2). Examples of the catalyst include triethylamine, benzylmethylamine, methyltriethylammonium chloride, benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, benzyltrimethylammonium iodide, and triphenylphosphine. The catalyst may be used alone or in combination of two or more.

[0031] The amount of the catalyst used may be 0.01 to 10 parts by mass, 0.05 to 2 parts by mass, or 0.1 to 1 part by mass, relative to 100 parts by mass of the total of the components (a1) and (a2), from the viewpoint of promoting the reaction between the components (a1) and (a2).

[0032] A polymerization inhibitor may be used in the reaction between component (a1) and component (a2) to prevent polymerization during the reaction. Examples of polymerization inhibitors include hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, catechol, and pyrogallol. One polymerization inhibitor may be used alone, or two or more polymerization inhibitors may be used in combination. From the viewpoint of improving stability, the amount of the polymerization inhibitor used may be 0.01 to 1 part by mass, 0.02 to 0.8 parts by mass, or 0.04 to 0.5 parts by mass, per 100 parts by mass of the total of component (a1) and component (a2).

[0033] The reaction temperature of the component (a1) and the component (a2) may be 60 to 150°C, 80 to 120°C, or 90 to 110°C from the viewpoint of productivity.

[0034] Component (A'), obtained by reacting components (a1) and (a2), has hydroxyl groups formed by a ring-opening addition reaction between the epoxy groups of component (a1) and the carboxyl groups of component (a2). By further reacting component (A') with component (a3), an acid-modified vinyl-group-containing epoxy resin is obtained in which the hydroxyl groups of component (A') (including the hydroxyl groups originally present in component (a1)) and the acid anhydride groups of component (a3) ​​are half-esterified.

[0035] Examples of component (a3) ​​include succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, ethyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, ethylhexahydrophthalic anhydride, and itaconic anhydride. Among these, tetrahydrophthalic anhydride is preferred from the viewpoint of via resolution. One type of component (a3) ​​may be used alone, or two or more types may be used in combination.

[0036] The reaction temperature of the component (A') and the component (a3) ​​may be 50 to 150°C, 60 to 120°C, or 70 to 100°C from the viewpoint of productivity.

[0037] In the reaction of component (A') with component (a3), for example, the acid value of component (A) can be adjusted by reacting 0.1 to 1.0 equivalents of component (a3) ​​with one equivalent of hydroxyl groups in component (A').

[0038] The acid value of component (A) may be 20 to 180 mgKOH / g, 30 to 150 mgKOH / g, or 40 to 120 mgKOH / g. When the acid value of component (A) is 20 mgKOH / g or more, the photosensitive resin composition tends to have excellent solubility in a dilute alkaline solution. When the acid value of component (A) is 180 mgKOH / g or less, the electrical properties of the permanent resist are easily improved.

[0039] The acid value can be measured in accordance with JIS K6901 5.3.2. For example, 30 g of acetone is added to approximately 1 g of a solution of component (A), and then phenolphthalein, an indicator, is added, and titration is performed using a 0.1 N aqueous potassium hydroxide solution. The acid value can be calculated using the following formula: Acid value (mg KOH / g) = 10 × Titration amount (mL) of aqueous potassium hydroxide solution × 56.1 / (Mass (g) of solution of component (A) × Mass (% by mass) of component (A))

[0040] The weight average molecular weight (Mw) of the component (A) may be 3,000 to 30,000, 5,000 to 20,000, or 7,000 to 15,000, from the viewpoint of film-forming properties.

[0041] Mw can be measured by gel permeation chromatography (GPC). Mw can be measured, for example, under the following GPC conditions, and the value converted using a calibration curve of standard polystyrene can be used as Mw. The calibration curve can be created using a 5-sample set ("PStQuick MP-H" and "PStQuick B", manufactured by Tosoh Corporation) as standard polystyrene. Apparatus: High-speed GPC apparatus "HCL-8320GPC" (manufactured by Tosoh Corporation) Detector: Differential refractometer (manufactured by Tosoh Corporation) Column: Column TSKgel SuperMultipore HZ-H (column length: 15 cm, column inner diameter: 4.6 mm) (manufactured by Tosoh Corporation) Eluent: Tetrahydrofuran (THF) Measurement temperature: 40°C Flow rate: 0.35 mL / min Sample concentration: 10 mg / 5 mL THF Injection volume: 20 μL

[0042] From the viewpoint of the heat resistance, electrical properties, and chemical resistance of the permanent resist, the content of the component (A) may be 5 to 60 mass%, 10 to 55 mass%, 20 to 50 mass%, 25 to 50 mass%, or 30 to 45 mass%, based on the total solid content of the photosensitive resin composition.

[0043] (Component (B): Photopolymerizable Compound) The photosensitive resin composition according to this embodiment contains a photopolymerizable compound as component (B). Component (B) is not particularly limited as long as it is a compound having a functional group exhibiting photopolymerizability. Examples of functional groups exhibiting photopolymerizability include groups having an ethylenically unsaturated bond, such as a vinyl group, an allyl group, a propargyl group, a butenyl group, an ethynyl group, a phenylethynyl group, a maleimide group, a nadimide group, and a (meth)acryloyl group. From the viewpoint of reactivity, component (B) may contain a compound having a (meth)acryloyl group.

[0044] Examples of the component (B) include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; mono- or di(meth)acrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, and polyethylene glycol; (meth)acrylamide compounds such as N,N-dimethyl(meth)acrylamide and N-methylol(meth)acrylamide; aminoalkyl (meth)acrylates such as N,N-dimethylaminoethyl (meth)acrylate; hexanediol, trimethylolpropane, pentaerythritol, and ditrimethylolpropane. , dipentaerythritol, tris-hydroxyethyl isocyanurate, and other polyhydric alcohols, or polyhydric (meth)acrylates of these ethylene oxide or propylene oxide adducts; (meth)acrylate compounds of ethylene oxide or propylene oxide adducts of phenolic compounds, such as phenoxyethyl (meth)acrylate and polyethoxydi(meth)acrylate of bisphenol A; (meth)acrylates of glycidyl ethers, such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate; and melamine (meth)acrylate. Component (B) can be used singly or in combination of two or more.

[0045] The content of component (B) may be 1 to 25 mass%, 2 to 20 mass%, 5 to 18 mass%, or 7 to 15 mass%, based on the total solid content in the photosensitive resin composition. When the content of component (B) is 1 mass% or more, the exposed area is less likely to dissolve during development, and when it is 25 mass% or less, heat resistance is more likely to be improved.

[0046] (Component (C): Photopolymerization Initiator) The photosensitive resin composition according to this embodiment contains a photopolymerization initiator as the component (C). The component (C) is not particularly limited as long as it can polymerize the components (A) and (B). The component (C) can be used alone or in combination of two or more.

[0047] Examples of the component (C) include benzoin compounds such as benzoin, benzoin methyl ether, and benzoin isopropyl ether; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-methyl-1-[4-(methylthio) ) phenyl]-2-morpholino-1-propanone, N,N-dimethylaminoacetophenone and other acetophenone compounds; 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone and other anthraquinone compounds; 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone ketal compounds such as acetophenone dimethyl ketal and benzil dimethyl ketal; benzophenone compounds such as benzophenone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bis(diethylamino)benzophenone, Michler's ketone and 4-benzoyl-4'-methyldiphenyl sulfide; acridine compounds such as 9-phenylacridine and 1,7-bis(9,9'-acridinyl)heptane; Examples thereof include acylphosphine oxide compounds such as trimethylbenzoyldiphenylphosphine oxide; and oxime ester compounds such as 1,2-octanedione-1-[4-(phenylthio)phenyl]-2-(O-benzoyloxime), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone-1-(O-acetyloxime), and 1-phenyl-1,2-propanedione-2-[O-(ethoxycarbonyl)oxime].

[0048] The component (C) may contain an acetophenone compound from the viewpoint of being less likely to volatilize and generate outgassing, or may contain a thioxanthone compound from the viewpoint of improving photocurability even in the visible light range.

[0049] The content of component (C) is not particularly limited, and may be 0.1 to 10 mass%, 0.1 to 5 mass%, 0.2 to 1 mass%, or 0.2 to 0.8 mass%, based on the total solid content of the photosensitive resin composition. If the content of component (C) is 0.1 mass% or more, the exposed area is less likely to dissolve during development, and if it is 10 mass% or less, it is easier to suppress a decrease in heat resistance.

[0050] (Component (D): Thermosetting Resin) The photosensitive resin composition of the present embodiment contains a thermosetting resin as component (D). Component (D) does not include anything equivalent to component (B). When the photosensitive resin composition contains a thermosetting resin (D), the adhesion, insulation reliability, heat resistance, etc. of the permanent resist can be improved.

[0051] Examples of the component (D) include epoxy resins, phenolic resins, unsaturated imide resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, and melamine resins. The component (D) can be used alone or in combination of two or more.

[0052] Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol A novolac type epoxy resins, bisphenol F novolac type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, biphenyl novolac type epoxy resins, phenol aralkyl type epoxy resins, stilbene type epoxy resins, naphthalene type epoxy resins, naphthol novolac type epoxy resins, naphthol type epoxy resins, naphthol aralkyl type epoxy resins, naphthylene ether type epoxy resins, biphenyl type epoxy resins, biphenyl aralkyl type epoxy resins, xylylene type epoxy resins, dihydroanthracene type epoxy resins, dicyclopentadiene type epoxy resins, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane dimethanol type epoxy resins, trimethylol type epoxy resins, aliphatic linear epoxy resins, and rubber-modified epoxy resins.

[0053] From the viewpoints of heat resistance and insulation reliability, the component (D) may contain at least one selected from the group consisting of bisphenol-based epoxy resins, naphthol-type epoxy resins, naphthalene-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, and cresol novolac-type epoxy resins, and preferably contains a bisphenol A-type epoxy resin, a bisphenol F-type epoxy resin, or a biphenyl-type epoxy resin, more preferably contains a bisphenol F-type epoxy resin or a biphenyl-type epoxy resin, and even more preferably contains a biphenyl-type epoxy resin.

[0054] The content of the component (D) is 5 to 50% by mass, and may be 5 to 40% by mass, 7 to 30% by mass, or 10 to 25% by mass, based on the total solid content of the photosensitive resin composition. When the content of the component (D) is 5% by mass or more, the heat resistance of the formed permanent resist can be further improved while maintaining better developability, and when the content of the component (D) is 50% by mass or less, the via resolution is better.

[0055] (Component (E): Pigment) The photosensitive resin composition according to this embodiment contains a pigment as component (E) according to the desired color in order to adjust photosensitivity properties, etc. As component (E), a colorant that develops a desired color when concealing wiring (conductor pattern), etc., can be used.

[0056] Examples of the component (E) include phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, carbon black, and naphthalene black. The component (E) can be used alone or in combination of two or more.

[0057] From the viewpoints of making the production equipment easier to identify and further concealing the wiring, the content of the component (E) may be 0.1 to 5.0 mass%, 0.3 to 3.0 mass%, or 0.5 to 2.0 mass% based on the total solid content of the photosensitive resin composition.

[0058] (Component (F): Elastomer) The photosensitive resin composition according to this embodiment may contain an elastomer as component (F). By containing component (F), it is possible to improve via resolution, adhesion, and insulation reliability, and to suppress a decrease in flexibility and adhesive strength caused by distortion (internal stress) inside the resin due to cure shrinkage of component (A).

[0059] Examples of component (F) include styrene-based elastomers, olefin-based elastomers, urethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, acrylic elastomers, and silicone-based elastomers. These elastomers are composed of a hard segment component that contributes to heat resistance and strength and a soft segment component that contributes to flexibility and toughness. Component (F) can be used alone or in combination of two or more.

[0060] Examples of styrene-based elastomers include styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, styrene-ethylene-butylene-styrene block copolymers, and styrene-ethylene-propylene-styrene block copolymers. In addition to styrene, styrene derivatives such as α-methylstyrene, 3-methylstyrene, 4-propylstyrene, and 4-cyclohexylstyrene can be used as components constituting the styrene-based elastomers.

[0061] The number average molecular weight (Mn) of the styrene elastomer may be 1,000 to 50,000, 2,000 to 30,000, or 3,000 to 20,000. The Mn of component (F) is a value measured by GPC and calculated in terms of standard polystyrene.

[0062] Examples of olefin-based elastomers include ethylene-propylene copolymers, ethylene-α-olefin copolymers, ethylene-α-olefin-non-conjugated diene copolymers, propylene-α-olefin copolymers, butene-α-olefin copolymers, ethylene-propylene-diene copolymers, copolymers of non-conjugated dienes such as dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylenenorbornene, ethylidenenorbornene, butadiene, and isoprene with α-olefins, epoxy-modified polybutadiene, and carboxylic acid-modified butadiene-acrylonitrile copolymers.

[0063] The epoxy-modified polybutadiene preferably has hydroxyl groups at the molecular terminals, more preferably at both molecular terminals, and even more preferably at only both molecular terminals. The number of hydroxyl groups that the epoxy-modified polybutadiene has may be one or more, preferably 1 to 5, more preferably 1 or 2, and even more preferably 2.

[0064] The Mn of the olefinic elastomer may be 1,000 to 5,000, 1,200 to 3,000, or 1,500 to 3,500.

[0065] As the urethane-based elastomer, a compound composed of a hard segment made of a low molecular weight (short chain) diol and diisocyanate, and a soft segment made of a high molecular weight (long chain) diol and diisocyanate can be used.

[0066] Examples of short-chain diols include ethylene glycol, propylene glycol, 1,4-butanediol, and bisphenol A. The number average molecular weight of the short-chain diol is preferably 48 to 500.

[0067] Examples of long-chain diols include polypropylene glycol, polytetramethylene oxide, poly(1,4-butylene adipate), poly(ethylene-1,4-butylene adipate), polycaprolactone, poly(1,6-hexylene carbonate), and poly(1,6-hexylene-neopentylene adipate). The number-average molecular weight of the long-chain diol is preferably 500 to 10,000.

[0068] As the polyester-based elastomer, a compound (for example, polyester resin) obtained by polycondensation of a dicarboxylic acid or a derivative thereof with a diol compound or a derivative thereof can be used.

[0069] Examples of dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid; aliphatic dicarboxylic acids having 2 to 20 carbon atoms such as adipic acid, sebacic acid, and dodecanedicarboxylic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. The dicarboxylic acids can be used alone or in combination of two or more.

[0070] Examples of the diol compound include aliphatic diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and 1,10-decanediol; alicyclic diols such as 1,4-cyclohexanediol; and aromatic diols such as bisphenol A, bis-(4-hydroxyphenyl)methane, bis-(4-hydroxy-3-methylphenyl)propane, and resorcinol.

[0071] The Mn of the urethane-based elastomer may be 1,000 to 25,000, 1,500 to 20,000, or 2,000 to 15,000.

[0072] Polyester elastomers can be multiblock copolymers that use aromatic polyesters (e.g., polybutylene terephthalate) as hard segment components and aliphatic polyesters (e.g., polytetramethylene glycol) as soft segment components. There are various grades of polyester elastomers that differ in the type, ratio, and molecular weight of the hard and soft segments.

[0073] The Mn of the polyester-based elastomer may be 900 to 30,000, 1,000 to 25,000, or 5,000 to 20,000.

[0074] Polyamide elastomers are broadly classified into two types: polyether block amide type and polyether ester block amide type, which use polyamide for the hard segment and polyether or polyester for the soft segment. Examples of polyamides include polyamide-6, polyamide-11, and polyamide-12. Examples of polyethers include polyoxyethylene glycol, polyoxypropylene glycol, and polytetramethylene glycol.

[0075] The Mn of the polyamide-based elastomer may be 1,000 to 50,000, 1,500 to 40,000, or 2,000 to 30,000.

[0076] The acrylic elastomer may be a compound containing a structural unit based on a (meth)acrylic acid ester as a main component. Examples of (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, methoxyethyl (meth)acrylate, and ethoxyethyl (meth)acrylate. The acrylic elastomer may be a compound obtained by copolymerizing a (meth)acrylic acid ester with acrylonitrile, or may be a compound obtained by further copolymerizing a monomer having a functional group that serves as a crosslinking point. Examples of monomers having a functional group include glycidyl methacrylate and allyl glycidyl ether.

[0077] Examples of acrylic elastomers include acrylonitrile-butyl acrylate copolymer, acrylonitrile-butyl acrylate-ethyl acrylate copolymer, methyl methacrylate-butyl acrylate-methacrylic acid copolymer, and acrylonitrile-butyl acrylate-glycidyl methacrylate copolymer. As the acrylic elastomer, acrylonitrile-butyl acrylate-glycidyl methacrylate copolymer or methyl methacrylate-butyl acrylate-methacrylic acid copolymer is preferred, and methyl methacrylate-butyl acrylate-methacrylic acid copolymer is more preferred.

[0078] The Mn of the acrylic elastomer may be 1,000 to 50,000, 1,500 to 40,000, or 2,000 to 30,000.

[0079] Silicone elastomers are compounds primarily composed of organopolysiloxane. Examples of organopolysiloxane include polydimethylsiloxane, polymethylphenylsiloxane, and polydiphenylsiloxane. Silicone elastomers may be compounds in which a portion of an organopolysiloxane is modified with a vinyl group, an alkoxy group, or the like.

[0080] The Mn of the silicone-based elastomer may be 1,000 to 50,000, 1,500 to 40,000, or 2,000 to 30,000.

[0081] From the viewpoint of compatibility and solubility, the component (F) preferably contains at least one selected from the group consisting of an olefin-based elastomer, a polyester-based elastomer, and a urethane-based elastomer, and more preferably contains a polyester-based elastomer.

[0082] The content of component (F) may be 0.5 to 20 mass%, 1.0 to 15 mass%, 1.5 to 10 mass%, or 2.0 to 6.0 mass%, based on the total solid content of the photosensitive resin composition. When the content of component (F) is 0.5 mass% or more, the insulation reliability tends to be even better. When the content of component (F) is 20 mass% or less, both the via resolution and the insulation reliability tend to be sufficient.

[0083] (Component (G): Inorganic Filler) The photosensitive resin composition of the present embodiment may contain an inorganic filler other than silica as component (G). By containing component (G), the thermal expansion of the permanent resist can be reduced, making it less likely to warp. The component (G) may be used alone or in combination of two or more.

[0084] Examples of component (G) include alumina, titania, tantalum oxide, zirconia, silicon nitride, barium titanate, barium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, lead titanate, lead zirconate titanate, lead lanthanum zirconate titanate, gallium oxide, spinel, mullite, cordierite, talc, aluminum titanate, yttria-containing zirconia, barium silicate, boron nitride, calcium carbonate, barium sulfate, calcium sulfate, zinc oxide, magnesium titanate, hydrotalcite, mica, calcined kaolin, and carbon.

[0085] The component (G) may contain barium sulfate from the viewpoint of improving the heat resistance and adhesive strength of the permanent resist. From the viewpoint of improving the dispersibility of the inorganic filler, an inorganic filler that has been surface-treated in advance with alumina or an organic silane compound may be used.

[0086] From the viewpoint of via resolution, the average particle size of the component (G) may be 0.01 to 5.0 μm, 0.1 to 3.0 μm, 0.1 to 2.0 μm, or 0.1 to 1.0 μm.

[0087] The average particle size of component (G) is the volume-average particle size of the inorganic filler in a state dispersed in the photosensitive resin composition, and is a value obtained by measuring as follows: First, the photosensitive resin composition is diluted (or dissolved) 1000 times with methyl ethyl ketone, and then the particles dispersed in the solvent are measured using a submicron particle analyzer (manufactured by Beckman Coulter, Inc., product name "N5") in accordance with international standard ISO 13321 at a refractive index of 1.38, and the particle size at an integrated value of 50% (volume basis) in the particle size distribution is taken as the average particle size (volume-average particle size).

[0088] The content of the component (G) may be 0 to 60 mass%, 10 to 60 mass%, 20 to 55 mass%, or 30 to 50 mass%, based on the total solid content of the photosensitive resin composition. When the content of the component (G) is within the above range, it is possible to improve the mechanical strength, heat resistance, via resolution, etc.

[0089] (Other Components) The photosensitive resin composition according to this embodiment may further contain various additives as needed. Examples of the additives include polymerization inhibitors such as hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, catechol, and pyrogallol; thickeners such as bentone and montmorillonite; antifoaming agents such as silicone-based antifoaming agents, fluorine-based antifoaming agents, and vinyl resin-based antifoaming agents; silane coupling agents; and flame retardants such as brominated epoxy compounds, acid-modified brominated epoxy compounds, antimony compounds, phosphate compounds, aromatic condensed phosphate esters, and halogen-containing condensed phosphate esters.

[0090] (Solvent) The photosensitive resin composition according to this embodiment contains a solvent for dissolving and dispersing each component, which makes it easy to apply the composition onto a substrate and allows a coating film of uniform thickness to be formed.

[0091] Examples of solvents include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, propylene glycol monoethyl ether acetate, butyl cellosolve acetate, and carbitol acetate; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. The solvents may be used alone or in combination of two or more.

[0092] The amount of the solvent to be added is not particularly limited, but the ratio of the solvent in the photosensitive resin composition may be 10 to 50% by mass, 20 to 40% by mass, or 25 to 35% by mass.

[0093] The photosensitive resin composition according to this embodiment can be obtained by kneading and mixing the components using a roll mill, a bead mill, or the like.

[0094] The lightness L of a 20 μm-thick resin film formed by applying the photosensitive resin composition according to this embodiment to a substrate and drying it ＊ It is preferable that the L of the resin film is less than 40. ＊ The larger the value, the whiter the color of the resin film becomes and the lower the resolution. ＊ From the viewpoint of further improving the resolution, it may be 38 or less, 36 or less, or 35 or less, and from the viewpoint of further concealing the wiring, it may be 30 or more, 31 or more, 32 or more, or 33 or more.

[0095] [Photosensitive Element] The photosensitive element according to this embodiment includes a support film and a photosensitive layer containing the above-described photosensitive resin composition. Fig. 1 is a cross-sectional view schematically showing the photosensitive element according to this embodiment. As shown in Fig. 1, the photosensitive element 1 includes a support film 10 and a photosensitive layer 20 formed on the support film 10.

[0096] The photosensitive element 1 can be produced by applying the photosensitive resin composition according to this embodiment onto a support film 10 by a known method such as reverse roll coating, gravure roll coating, comma coating, or curtain coating, and then drying the coating to form a photosensitive layer 20.

[0097] Examples of the support film include polyester films such as polyethylene terephthalate and polybutylene terephthalate; and polyolefin films such as polypropylene and polyethylene. The thickness of the support film may be, for example, 5 to 100 μm, 5 to 60 μm, or 15 to 45 μm. The thickness of the photosensitive layer may be, for example, 1 to 50 μm, 5 to 40 μm, or 10 to 30 μm.

[0098] The coating film can be dried by hot air drying, far infrared drying, or near infrared drying. The drying temperature may be 60 to 150° C., 70 to 120° C., or 80 to 100° C. The drying time may be 1 to 60 minutes, 2 to 30 minutes, or 5 to 20 minutes.

[0099] The content of the solvent remaining in the photosensitive layer, which is a coating film after drying, may be 3% by mass or less, 2% by mass or less, or 1% by mass or less, from the viewpoint of avoiding diffusion of the solvent during the manufacturing process of the printed wiring board.

[0100] The photosensitive element 1 may further include a protective film 30 on the photosensitive layer 20 to cover the photosensitive layer 20. The photosensitive element 1 may also have the protective film 30 laminated on the surface of the photosensitive layer 20 opposite to the surface that contacts the support film 10. The protective film 30 may be, for example, a polymer film such as polyethylene or polypropylene.

[0101] The solid content of each component (components (A) to (G) and other components) other than the volatile substance in the photosensitive layer 20 may be in the same range as the solid content of each component in the photosensitive resin composition.

[0102] [Printed Wiring Board] The printed wiring board according to this embodiment includes a permanent resist containing a cured product of the photosensitive resin composition according to this embodiment, which can improve insulation reliability and crack resistance.

[0103] The method for producing a printed wiring board according to this embodiment includes the steps of forming a photosensitive layer on a substrate using the above-described photosensitive resin composition or photosensitive element, exposing and developing the photosensitive layer to form a resist pattern, and curing the resist pattern to form a permanent resist. An example of each step will be described below.

[0104] First, a substrate such as a copper-clad laminate is prepared, and a photosensitive layer is formed on the substrate. The photosensitive layer may be formed by applying a photosensitive resin composition to the substrate and drying it. Examples of methods for applying the photosensitive resin composition include screen printing, spraying, roll coating, curtain coating, and electrostatic coating. The drying temperature may be 60 to 120°C, 70 to 110°C, or 80 to 100°C. The drying time may be 1 to 7 minutes, 1 to 6 minutes, or 2 to 5 minutes.

[0105] The photosensitive layer may be formed on the substrate by peeling off the protective film from the photosensitive element and laminating the photosensitive layer on the substrate. Examples of methods for laminating the photosensitive layer include thermal lamination using a laminator.

[0106] Next, a negative film is brought into contact with the photosensitive layer directly or via a support film, and the layer is exposed to actinic rays. Examples of actinic rays include electron beams, ultraviolet rays, and X-rays, with ultraviolet rays being preferred. Examples of light sources that can be used include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and halogen lamps. The exposure dose is 10 to 2000 mJ / cm. ２ , 100-1500mJ / cm ２ , or 300 to 1000 mJ / cm ２ may be.

[0107] After exposure, the unexposed areas are removed with a developer to form a resist pattern. Examples of the developing method include dipping and spraying. Examples of the developer that can be used include aqueous alkali solutions such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, and tetramethylammonium hydroxide.

[0108] A patterned cured film (permanent resist) can be formed by subjecting the resist pattern to at least one of post-exposure and post-heating. The exposure dose of the post-exposure is 100 to 5000 mJ / cm. ２ , 500-2000mJ / cm ２ , or 700 to 1500 J / cm ２ The heating temperature of the post-heating may be 100 to 200° C., 120 to 180° C., or 135 to 165° C. The heating time of the post-heating may be 5 minutes to 12 hours, 10 minutes to 6 hours, or 30 minutes to 2 hours.

[0109] The permanent resist according to this embodiment can be used as an interlayer insulating layer or a surface protective layer of a semiconductor element. A semiconductor element having an interlayer insulating layer or a surface protective layer formed from a cured film of the above-described photosensitive resin composition, and an electronic device including the semiconductor element, can be produced. The semiconductor element may be, for example, a memory, a package, or the like having a multilayer wiring structure, a rewiring structure, or the like. Examples of electronic devices include mobile phones, smartphones, tablet terminals, personal computers, and hard disk suspensions. By providing a patterned cured film formed from the photosensitive resin composition according to this embodiment, semiconductor elements and electronic devices with excellent reliability can be provided.

[0110] The present disclosure will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0111] Synthesis Example 1: 1,052 parts by weight of bisphenol F epoxy resin (epoxy equivalent: 526), ​​144 parts by weight of acrylic acid, 1 part by weight of methylhydroquinone, 850 parts by weight of carbitol acetate, and 100 parts by weight of solvent naphtha were mixed with stirring at 70°C. The mixed solution was cooled to 50°C, and 2 parts by weight of triphenylphosphine and 75 parts by weight of solvent naphtha were added. The mixture was reacted at 100°C until the acid value of the solution reached 1 mgKOH / g or less. After the reaction solution was cooled to 50°C, 745 parts by weight of tetrahydrophthalic anhydride (THPAC), 75 parts by weight of carbitol acetate, and 75 parts by weight of solvent naphtha were added, and the mixture was reacted at 80°C for 6 hours. Thereafter, the reaction solution was cooled to room temperature to obtain a solution of acid-modified epoxy acrylate (A-1) (solid acid value: 80 mg KOH / g, solid concentration: 62 mass %) as component (A).

[0112] (Synthesis Example 2) 250 parts by mass of dicyclopentadiene epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name "XD-1000", epoxy equivalent: 252, softening point: 74.2 ° C.), 70 parts by mass of acrylic acid, 0.5 parts by mass of methyl hydroquinone, and 120 parts by mass of carbitol acetate were mixed with stirring at 90 ° C. The mixed solution was cooled to 60 ° C., 2 parts by mass of triphenylphosphine was added, and the mixture was reacted at 100 ° C. until the acid value of the solution reached 1 mg KOH / g. 98 parts by mass of tetrahydrophthalic anhydride and 85 parts by mass of carbitol acetate were added to the reaction solution, and the mixture was reacted at 80 ° C. for 6 hours. Thereafter, the mixture was cooled to room temperature to obtain a solution of acid-modified epoxy acrylate (A-2) (solid acid value: 60 mg KOH / g, solid concentration: 73 mass%).

[0113] The following materials were prepared as components (B) to (G): B-1: Dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (manufactured by Nippon Kayaku Co., Ltd., trade name "KAYARAD DPHA") C-1: 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone (manufactured by IGM Resins B.V., trade name "Omirad 907") C-2: 2,4-diethylthioxanthone (manufactured by IGM Resins B.V., trade name "Omnirad DETX") D-1: Biphenyl-type epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name "YX-4000") E-1: Anthraquinone-based pigment (manufactured by Nippon Pigment Co., Ltd., trade name "R177") E-2: Diketopyrrolopyrrole pigment (manufactured by Nippon Pigment Co., Ltd., product name "R291") F-1: Polyester elastomer (manufactured by Resonac Corporation, product name "Teslac 2505-63") G-1: Barium sulfate (average primary particle size: 300 nm) G-2: Amorphous silica (average primary particle size: 500 nm)

[0114] [Photosensitive Resin Composition] The components were blended in the amounts (parts by mass, solid content equivalent) shown in Table 1 and kneaded using a three-roll mill. Then, carbitol acetate was added so that the solid content concentration became 60% by mass, thereby preparing a photosensitive resin composition.

[0115] [Photosensitive element] A 25 μm thick polyethylene terephthalate film (manufactured by Teijin Limited, product name "G2-25") was prepared as a support film. A photosensitive resin composition was applied onto the support film so that the thickness after drying would be 20 μm, and the composition was dried at 75°C for 30 minutes using a hot air convection dryer to form a photosensitive layer. Subsequently, a biaxially oriented polypropylene film (manufactured by Oji F-Tex Co., Ltd., product name "MA-411") was laminated as a protective film onto the surface of the photosensitive layer opposite the side in contact with the support film, thereby obtaining a photosensitive element.

[0116] (Hue) The protective film was peeled off from the photosensitive element. The lightness L including specular reflection light was measured using a spectrophotometer (manufactured by Konica Minolta, Inc., product name "CM-5") with the photosensitive layer as the measurement surface. ＊ asked for.

[0117] [Evaluation of Resolution] (Preparation of Evaluation Laminate) The copper foil surface of a printed wiring board substrate (manufactured by Resonac Corporation, product name "MCL-E-679") in which a 12 μm thick copper foil was laminated on a glass epoxy base material was treated with a roughening pretreatment solution (manufactured by MEC Co., Ltd., product name "CZ-8100"), followed by rinsing with water and drying to obtain a roughening pretreated printed wiring board substrate. The protective film was peeled off and removed from the photosensitive element, and the exposed photosensitive layer was placed so as to abut against the copper foil of the roughening pretreated printed wiring board substrate. Then, a lamination process was performed using a press-type vacuum laminator (manufactured by Meiki Seisakusho Co., Ltd., product name "MVLP-500"). The lamination conditions were a press hot plate temperature of 70°C, a vacuuming time of 20 seconds, a lamination press time of 30 seconds, an atmospheric pressure of 4 kPa or less, and a pressure of 0.4 MPa. After lamination, the laminate was left to stand at room temperature for at least 1 hour to obtain a laminate for evaluation in which the photosensitive layer and the support film were laminated in this order on the copper foil surface of the substrate for printed wiring board.

[0118] (Measurement of Sensitivity of Photosensitive Layer) After peeling and removing the support film from the evaluation laminate, a 41-step tablet was placed on the photosensitive layer, and exposure was performed using a direct imaging exposure device (manufactured by ORC Manufacturing Co., Ltd., product name "DXP-3512") using an ultra-high pressure mercury lamp as a light source. The exposure pattern used was a pattern in which dots were arranged in a lattice (dot diameter: distance between dot centers = 1:2). The dot diameter (φ) was changed in 5 μm increments within the range of 30 to 100 μm. After exposure, the layer was left at room temperature for 30 minutes, and then the unexposed portions of the photosensitive layer were spray-developed for 60 seconds using a 1% by mass aqueous solution of sodium carbonate at 30°C. After development, the exposure amount at which the number of remaining gloss steps of the 41-step tablet was 8 was determined as the sensitivity (mJ / cm) of the photosensitive layer. ２ )

[0119] (Evaluation of via resolution) The via resolution was evaluated by exposing to an exposure dose that resulted in 8 remaining steps as measured above, followed by spray development, and then observing the via pattern using an optical microscope and evaluating according to the following criteria. The state of "opening" below indicates a state in which the copper foil of the printed wiring board substrate can be confirmed when the via portion of the dot pattern is observed using an optical microscope. A: The φ40 μm via portion of the dot pattern is open. B: The φ40 μm via portion of the dot pattern is not open.

[0120]

[0121] 1...photosensitive element, 10...support film, 20...photosensitive layer, 30...protective film

Claims

1. A photosensitive resin composition for permanent resist, which contains (A) an acid-modified vinyl group-containing resin, (B) a photopolymerizable compound, (C) a photopolymerization initiator, (D) a thermosetting resin, and (E) a pigment, and does not contain silica.

2. The lightness L of a 20 μm-thick resin film formed by applying the photosensitive resin composition to a substrate and drying it ＊ The photosensitive resin composition according to claim 1 , wherein the ρ is less than 40.

3. The photosensitive resin composition according to claim 1, further comprising (F) an elastomer.

4. The photosensitive resin composition according to claim 3, wherein the elastomer comprises a polyester-based elastomer.

5. A photosensitive element comprising a support film and a photosensitive layer formed on the support film, wherein the photosensitive layer comprises the photosensitive resin composition according to any one of claims 1 to 4.

6. A printed wiring board comprising a permanent resist containing a cured product of the photosensitive resin composition according to any one of claims 1 to 4.

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