Photosensitive resin composition, photosensitive element, printed wiring board, and printed wiring board production method

Abstract

A photosensitive resin composition for a permanent resist according to the present disclosure includes (A) an acid-modified vinyl group-containing resin, (B) a photopolymerizable compound, (C) a thermosetting resin, (D) an inorganic filler, (E) a photopolymerization initiator, and (F) a polymerization inhibitor, wherein (F) the polymerization inhibitor contains a nitroxyl radical compound, and the content of the nitroxyl radical compound is 0.015-0.40 pt.mass with respect to 100 pts.mass of the total amount of (A) the acid-modified vinyl group-containing resin, (B) the photopolymerizable compound, and (C) the thermosetting resin.

Description

Photosensitive resin composition, photosensitive element, printed circuit board, and method for manufacturing a printed circuit board.

[0001] This disclosure relates to a photosensitive resin composition for permanent resists, a photosensitive element, a printed circuit board, and a method for manufacturing a printed circuit board.

[0002] In the field of printed circuit boards (PCBs), permanent resist is formed on the PCBs. Permanent resist plays a role in preventing corrosion of the conductor layer and maintaining electrical insulation between conductor layers during the use of the PCB. In recent years, permanent resist has also taken on the role of a solder resist film in processes such as flip-chip mounting and wire bonding mounting of semiconductor elements onto PCBs via solder, preventing solder from adhering to unwanted areas of the conductor layer on the PCB.

[0003] Structures having openings formed from permanent resist (solder resist) on a circuit board include SMD (Solder Mask Defined) structures, which have openings in which a portion of the solder resist is in contact with pads (copper wiring), and NSMD (Non-Solder Mask Defined) structures, which have openings in which the solder resist is not in contact with the pads (see, for example, Patent Document 1).

[0004] Japanese Patent Publication No. 2023-137137

[0005] In the case of NSMD structures, since the solder resist does not come into contact with the pads, light reflection from the pad surface does not occur. Compared to SMD structures, this results in insufficient curing of the bottom of the solder resist, making undercuts more likely. When undercuts occur, the solder resist may peel off from the substrate starting from that point, so it is necessary to minimize undercuts at openings as much as possible.

[0006] The present disclosure aims to provide a photosensitive resin composition, a photosensitive element, a printed circuit board, and a method for manufacturing a printed circuit board that can reduce undercuts in the openings of an NSMD structure.

[0007] One aspect of the present disclosure relates to the following photosensitive resin composition, photosensitive element, printed circuit board, and method for manufacturing a printed circuit board: [1] A photosensitive resin composition for permanent resist, comprising (A) an acid-modified vinyl group-containing resin, (B) a photopolymerizable compound, (C) a thermosetting resin, (D) an inorganic filler, (E) a photopolymerization initiator, and (F) a polymerization inhibitor, wherein (F) the polymerization inhibitor comprises a nitroxyl radical compound, and the content of the nitroxyl radical compound is 0.015 to 0.40 parts by mass per 100 parts by mass of the total amount of (A) the acid-modified vinyl group-containing resin, (B) the photopolymerizable compound, and (C) the thermosetting resin. [2] The photosensitive resin composition according to [1], wherein the nitroxyl radical compound is a 2,2,6,6-tetramethylpiperidine-1-oxyl derivative. [3] The photosensitive resin composition according to [1] or [2] above, wherein the content of the nitroxyl radical compound is 0.025 to 0.30 parts by mass per 100 parts by mass of the total amount of (A) acid-modified vinyl group-containing resin, (B) photopolymerizable compound, and (C) thermosetting resin. [4] The photosensitive resin composition according to any one of [1] to [3] above, wherein (A) acid-modified vinyl group-containing resin comprises acid-modified bisphenol novolac type epoxy (meth)acrylate. [5] The photosensitive resin composition according to any one of [1] to [4] above, wherein (E) photopolymerization initiator comprises alkylphenone-based photopolymerization initiator and acylphosphine oxide-based photopolymerization initiator. [6] The photosensitive resin composition according to any one of [1] to [5] above, wherein the content of the nitroxyl radical compound is 0.031 to 0.50 parts by mass per 100 parts by mass of the total amount of (A) acid-modified vinyl group-containing resin and (B) photopolymerizable compound. [7] A photosensitive resin composition according to any one of [1] to [6] above, used for forming openings in an NSMD structure. [8] A photosensitive element comprising a support film and a photosensitive layer formed on the support film, wherein the photosensitive layer contains the photosensitive resin composition according to any one of [1] to [7] above. [9] A printed circuit board comprising a permanent resist containing a cured product of the photosensitive resin composition according to any one of [1] to [7] above.

[10] A method for manufacturing a printed wiring board, comprising: a step of forming a photosensitive layer on a substrate using the photosensitive resin composition according to any one of [1] to [7] above; a step of exposing and developing the photosensitive layer to form a resist pattern; and a step of curing the resist pattern to form a permanent resist.

[11] A method for manufacturing a printed wiring board, comprising: a step of forming a photosensitive layer on a substrate using the photosensitive element according to [8] above; a step of exposing and developing the photosensitive layer to form a resist pattern; and a step of curing the resist pattern to form a permanent resist.

[0008] According to the present disclosure, it is possible to provide a photosensitive resin composition, a photosensitive element, a printed wiring board, and a method for manufacturing a printed wiring board that can reduce the undercut in the opening of the NSMD structure.

[0009] FIG. 1 is a cross-sectional view schematically showing the photosensitive element according to the present embodiment. FIG. 2 is a cross-sectional view schematically showing the NSMD structure in the printed wiring board.

[0010] Hereinafter, an 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 they are clearly considered to be essential in principle when specifically stated. The same applies to numerical values and their ranges, and they do not unduly limit the present disclosure.

[0011] In the present disclosure, the term "layer" includes not only a structure formed over the entire surface when observed in a plan view but also a structure formed only in part. In the present disclosure, the term "step" includes not only an independent step but also a step that is included in this term if the intended purpose of the step is achieved even when it cannot be clearly distinguished from other steps.

[0012] In this disclosure, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages in this disclosure, the upper or lower limit of one stage of the numerical range may be replaced with the upper or lower limit of another stage of the numerical range. Also, in numerical ranges described in this disclosure, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples. In this disclosure, "A or B" means that either A or B is included, or both are included. Unless otherwise specified, the materials exemplified below may be used individually or in combination of two or more. In this disclosure, the content of each component in a composition means the total amount of multiple substances present in the composition if there are multiple substances corresponding to each component in the composition, unless otherwise specified.

[0013] In this disclosure, "solids" refers to the non-volatile components of a photosensitive resin composition, excluding volatile substances such as water and diluents. It includes components that remain without evaporating or volatilizing 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).

[0014] [Photosensitive Resin Composition] The photosensitive resin composition for permanent resist according to this embodiment contains (A) an acid-modified vinyl group-containing resin, (B) a photopolymerizable compound, (C) a photopolymerization initiator, (D) an inorganic filler, and (E) a polymerization inhibitor. In the photosensitive resin composition according to this embodiment, the (F) polymerization inhibitor contains a nitroxyl radical compound, and the content of the nitroxyl radical compound is 0.015 to 0.40 parts by mass per 100 parts by mass of the total amount of (A) the acid-modified vinyl group-containing resin, (B) the photopolymerizable compound, and (C) the thermosetting resin.

[0015] The photosensitive resin composition according to this embodiment contains components (A) to (E) as essential components, and by including a nitroxyl radical compound in a specific range as component (E), undercuts at the openings in the NSMD structure can be reduced. The photosensitive resin composition according to this embodiment is a negative-type photosensitive resin composition. Each component included in the photosensitive resin composition according to this embodiment will be described in detail below.

[0016] <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 group which is a photopolymerizable ethylenically unsaturated bond and an alkali-soluble acidic group.

[0017] Examples of groups having an ethylenically unsaturated bond in component (A) include vinyl groups, allyl groups, propargyl groups, butenyl groups, ethynyl groups, phenylethynyl groups, maleimide groups, nadiimide groups, and (meth)acryloyl groups. Among these, from the viewpoint of reactivity and resolution, the group having an ethylenically unsaturated bond may be a (meth)acryloyl group. Examples of acidic groups having component (A) include carboxyl groups, sulfol groups, and phenolic hydroxyl groups. Among these, from the viewpoint of resolution, the acidic group may be a carboxyl group.

[0018] Component (A) may be an acid-modified vinyl group-containing epoxy derivative obtained by reacting a resin (A') (hereinafter also referred to as "component (A')") obtained by reacting (a) an epoxy resin (hereinafter also referred to as "component (a)") with (b) an ethylenically unsaturated group-containing organic acid (hereinafter also referred to as "component (b)") with (c) a saturated or unsaturated group-containing polybasic acid anhydride (hereinafter also referred to as "component (c)").

[0019] Examples of acid-modified vinyl group-containing epoxy derivatives include acid-modified epoxy (meth)acrylate. Acid-modified epoxy (meth)acrylate is a resin obtained by acid-modifying epoxy (meth)acrylate, which is a reaction product of component (a) and component (b), with component (c). As acid-modified epoxy (meth)acrylate, for example, an addition product obtained by adding a saturated or unsaturated polybasic acid anhydride to an esterified product obtained by reacting an epoxy resin with a vinyl group-containing monocarboxylic acid can be used.

[0020] (a) Examples of components include epoxy resins having an alicyclic skeleton, novolac-type epoxy resins, and bisphenol-type epoxy resins. Examples of novolac-type epoxy resins include bisphenol novolac-type epoxy resins such as bisphenol A novolac-type epoxy resin, bisphenol F novolac-type epoxy resin, and bisphenol S novolac-type epoxy resin; phenol novolac-type epoxy resin, cresol novolac-type epoxy resin, biphenyl novolac-type epoxy resin, and naphthol novolac-type epoxy resin. Examples of bisphenol-type epoxy resins include bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, and bisphenol S-type epoxy resin.

[0021] Examples of component (A) include an acid-modified vinyl group-containing resin (A1) (hereinafter also referred to as "component (A1)") which uses a bisphenol novolac type epoxy resin (a1) (hereinafter also referred to as "epoxy resin (a1)") as component (a), and an acid-modified vinyl group-containing resin (A2) (hereinafter also referred to as "component (A2)") which uses an epoxy resin other than epoxy resin (a1) (hereinafter also referred to as "epoxy resin (a2)") as component (a). These can be used individually or in combination of two or more.

[0022] (Epoxy resin (a1)) Examples of epoxy resin (a1) include epoxy resins having structural units represented by the following formulas (I) or (II). Epoxy resin (a1) may also be an epoxy resin having structural units represented by formula (I).

[0023]

[0024] In formula (I), R １１ represents a hydrogen atom or a methyl group, and a plurality of R １１ may be the same or different. Y １ and Y ２ each independently represent a hydrogen atom or a glycidyl group, provided that at least one of Y １ and Y ２ is a glycidyl group. From the viewpoint of suppressing the occurrence of undercut and improving the linearity and resolution of the resist pattern profile, R １１ may be a hydrogen atom, and from the viewpoint of further improving the thermal shock resistance, Y １ and Y ２ may be glycidyl groups.

[0025] The number of structural units represented by formula (I) in the epoxy resin (a1) is 1 or more, and may be 10 to 100, 15 to 80, or 15 to 70. When the number of structural units is within the above range, it becomes easier to improve the linearity of the resist pattern profile, the adhesion to the copper substrate, the heat resistance, and the electrical insulation. Here, the number of structural units represents an integer value in a single molecule and a rational number that is an average value in an aggregate of a plurality of types of molecules. Hereinafter, the same applies to the number of structural units of the structural unit.

[0026]

[0027] In formula (II), R １２ represents a hydrogen atom or a methyl group, and a plurality of R １２ may be the same or different. Y ３ and Y ４ each independently represent a hydrogen atom or a glycidyl group, provided that at least one of Y ３ and Y ４ １２ is a glycidyl group. From the viewpoint of suppressing the occurrence of undercut and improving the linearity and resolution of the resist pattern profile, R １２ may be a hydrogen atom, and from the viewpoint of further improving the thermal shock resistance, Y ３ and Y ４ may be glycidyl groups.

[0028] The number of structural units represented by formula (II) in the epoxy resin (a1) is 1 or more, and may be 10 to 100, 15 to 80, or 15 to 70. When the number of structural units is within the above range, it becomes easier to improve the linearity of the resist pattern contour, adhesion to the copper substrate, and heat resistance.

[0029] In equation (II), R １２ This is a hydrogen atom, Y ３ and Y ４ Epoxy resins in which R is a glycidyl group are commercially available as the EXA-7376 series (manufactured by DIC Corporation, trade name). In formula (II), R １２ is a methyl group, Y ３ and Y ４ Epoxy resins with a glycidyl group are commercially available as the EPON SU8 series (manufactured by Westlake, trade name).

[0030] (Epoxy resin (a2)) The epoxy resin (a2) is not particularly limited as long as it is a different epoxy resin from epoxy resin (a1), but from the viewpoint of suppressing the occurrence of undercuts and improving the linearity of the resist pattern contour, adhesion to the copper substrate, and resolution, it may be at least one selected from the group consisting of novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, triphenolmethane type epoxy resin, and biphenyl type epoxy resin.

[0031] Examples of novolac-type epoxy resins include epoxy resins having structural units represented by the following formula (III). Examples of bisphenol A-type epoxy resins or bisphenol F-type epoxy resins include epoxy resins having structural units represented by the following formula (IV). Examples of triphenolmethane-type epoxy resins include epoxy resins having structural units represented by the following formula (V). Examples of biphenyl-type epoxy resins include epoxy resins having structural units represented by the following formula (VI).

[0032] As the epoxy resin (a2), a novolac-type epoxy resin having a structural unit represented by the following formula (III) may be used. Examples of novolac-type epoxy resins having such a structural unit include a novolac-type epoxy resin represented by the following formula (III').

[0033]

[0034] In equations (III) and (III'), R １３ Y represents a hydrogen atom or a methyl group. ５ Y represents a hydrogen atom or a glycidyl group, ５ At least one of them is a glycidyl group. In formula (III'), n １ is a number greater than or equal to 1, and there are multiple R １３ and Y ５ These may be the same or different. From the viewpoint of suppressing the occurrence of undercuts and improving the linearity and resolution of the resist pattern contour, R １３ This could be a hydrogen atom.

[0035] In formula (III'), Y is a hydrogen atom. ５ and the glycidyl group Y ５ The molar ratio may be 0 / 100 to 30 / 70 or 0 / 100 to 10 / 90, from the viewpoint of suppressing the occurrence of undercuts and improving the linearity and resolution of the resist pattern contour. １ n is 1 or greater, but may be 10-200, 30-150, or 30-100. １ When the values ​​are within the above range, the linearity of the resist pattern contour, adhesion to the copper substrate, and heat resistance tend to improve.

[0036] Examples of novolac-type epoxy resins represented by formula (III') include phenol novolac-type epoxy resins and cresol novolac-type epoxy resins. These novolac-type epoxy resins can be obtained, for example, by reacting a phenol novolac resin or a cresol novolac resin with epichlorohydrin using a known method.

[0037] Examples of commercially available phenol novolac type epoxy resins or cresol novolac type epoxy resins represented by formula (III') include YDCN-700-7, YDCN-700-10, YDCN-704, YDCN-704A, YDPN-638 (all manufactured by Nippon Steel Chemical & Material Co., Ltd., trade names), EOCN-102S, EOCN-103S, EOCN-104S, BREN-S (all manufactured by Nippon Kayaku Co., Ltd., trade names), N-740, N-770, N-665, N-673 (all manufactured by DIC Corporation, trade names).

[0038] Examples of epoxy resins (a2) include bisphenol A type epoxy resins or bisphenol F type epoxy resins having a structural unit represented by the following formula (IV). Examples of epoxy resins having such a structural unit include bisphenol A type epoxy resins or bisphenol F type epoxy resins represented by the following formula (IV').

[0039]

[0040] In formulas (IV) and (IV'), R １４ R represents a hydrogen atom or a methyl group, and there are multiple R groups. １４ They may be the same or different, Y ６ Y represents a hydrogen atom or a glycidyl group. ６ At least one of them is a glycidyl group. In formula (IV'), n ２ n represents a number greater than or equal to 1. ２ If there are two or more Y ６ They may be the same or different.

[0041] From the viewpoint of suppressing the occurrence of undercuts and improving the linearity and resolution of the resist pattern contour, R １４ Y may be a hydrogen atom, and from the viewpoint of further improving thermal shock resistance, ６ n may be a glycidyl group. ２ n indicates 1 or more, but may be 10 to 100, 10 to 80, or 15 to 60. ２ When the values ​​are within the above range, the linearity of the resist pattern contour, adhesion to the copper substrate, and heat resistance tend to improve.

[0042] Y in equation (IV) ６ A bisphenol A-type epoxy resin or a bisphenol F-type epoxy resin in which is a glycidyl group is, for example, Y in formula (IV). ６ The hydroxyl group (-OY) of a bisphenol A type epoxy resin or bisphenol F type epoxy resin is a hydrogen atom. ６ It can be obtained by reacting it with epichlorohydrin.

[0043] To accelerate the reaction between the hydroxyl group and epichlorohydrin, the reaction may be carried out at a reaction temperature of 50 to 120°C in the presence of an alkali metal hydroxide and in a polar organic solvent such as dimethylformamide, dimethylacetamide, or dimethyl sulfoxide. Keeping the reaction temperature within this range prevents the reaction from becoming too slow and suppresses side reactions.

[0044] Examples of commercially available bisphenol A-type epoxy resins or bisphenol F-type epoxy resins represented by formula (IV') include jER807, jER825, jER827, jER828, jER834, jER1004F, jER1007FS, jER1009F (all manufactured by Mitsubishi Chemical Corporation, trade names), YD-8125, YDF-170, YDF-2001, YDF-2004, YDF-8170C (all manufactured by Nippon Steel Chemical & Material Co., Ltd., trade names).

[0045] Examples of epoxy resins (a2) include triphenolmethane type epoxy resins having structural units represented by the following formula (V). Examples of triphenolmethane type epoxy resins having such structural units include triphenolmethane type epoxy resins represented by the following formula (V').

[0046]

[0047] In equations (V) and (V'), Y ７ Y represents a hydrogen atom or a glycidyl group, and there are multiple Y ７ They may be the same or different, and there is at least one Y ７ n is a glycidyl group. In formula (V'), n ３ This represents a number greater than or equal to 1.

[0048] From the viewpoint of suppressing the occurrence of undercuts and upper defects and improving the linearity and resolution of the resist pattern contour, Y ７ Y is a hydrogen atom in ７ and the glycidyl group Y ７ The molar ratio of Y may be 0 / 100 to 30 / 70. As can be seen from this molar ratio, ７ At least one of them is a glycidyl group. ３ n is 1 or greater, but may be 10-100, 15-80, or 15-70. ３ When the values ​​are within the above range, the linearity of the resist pattern contour, adhesion to the copper substrate, and heat resistance tend to improve.

[0049] Examples of triphenolmethane-type epoxy resins represented by formula (V') include FAE-2500, EPPN-501H, and EPPN-502H (all manufactured by Nippon Kayaku Co., Ltd., trade names), which are commercially available.

[0050] Examples of epoxy resins (a2) include biphenyl-type epoxy resins having structural units represented by the following formula (VI). Examples of biphenyl-type epoxy resins having such structural units include biphenyl-type epoxy resins represented by the following formula (VI').

[0051]

[0052] In equations (VI) and (VI'), Y ８ Y represents a hydrogen atom or a glycidyl group, and there are multiple Y ８ They may be the same or different, and there is at least one Y ８ n is a glycidyl group. In formula (VI'), n ４ This represents a number greater than or equal to 1.

[0053] Examples of biphenyl-type epoxy resins represented by formula (VI') include NC-3000, NC-3000-L, NC-3000-H, and NC-3000-FH-75M (all manufactured by Nippon Kayaku Co., Ltd., trade names), which are commercially available.

[0054] The epoxy resin (a2) may include at least one selected from the group consisting of a novolac-type epoxy resin having a structural unit represented by formula (III), a bisphenol A-type epoxy resin having a structural unit represented by formula (IV), and a bisphenol F-type epoxy resin having a structural unit represented by formula (IV), and may also include a bisphenol F-type epoxy resin having a structural unit represented by formula (IV).

[0055] From the viewpoint of thermal shock resistance, warp reduction, and resolution, a combination of component (A1), which uses a bisphenol novolac type epoxy resin having a structural unit represented by the above formula (I) as component (a1), and component (A2), which uses a bisphenol A type epoxy resin or a bisphenol F type epoxy resin having a structural unit represented by the formula (IV) as component (a2), may be used.

[0056] (Organic acid containing ethylenically unsaturated groups (b)) Examples of component (b) include acrylic acid; acrylic acid derivatives such as acrylic acid dimers, methacrylic acid, β-furfurylacrylic acid, β-styrylacrylic acid, cinnamic acid, crotonic acid, and α-cyanocinnamic acid; semi-ester compounds which are reaction products of hydroxyl group-containing (meth)acrylates and dibasic acid anhydrides; and semi-ester compounds which are reaction products of vinyl group-containing monoglycidyl ethers or vinyl group-containing monoglycidyl esters and dibasic acid anhydrides. Component (b) can be used alone or in combination of two or more.

[0057] Semi-ester compounds 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.

[0058] 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, trimethylolpropanedi(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and glycidyl (meth)acrylate.

[0059] 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.

[0060] In the reaction between component (a) and component (b), the reaction may be carried out in a ratio of 0.6 to 1.05 equivalents of component (b) per 1 equivalent of epoxy group of component (a), or in a ratio of 0.7 to 1.02 equivalents of component (b), or in a ratio of 0.8 to 1.0 equivalents of component (b). By reacting in such ratios, the photosensitivity tends to increase and the linearity of the resist pattern contour tends to improve.

[0061] A polymerization inhibitor may be used in the reaction between component (a) and component (b) 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 in combination of two or more. From the viewpoint of improving stability, the amount of 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 components (a) and (b).

[0062] Component (A'), obtained by reacting component (a) and component (b), has a hydroxyl group formed by a ring-opening addition reaction between the epoxy group of component (a) and the carboxyl group of component (b). By further reacting component (A') with component (c), 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 (a)) and the acid anhydride group of component (c) are semi-esterified.

[0063] (Polybasic acid anhydride (c)) Examples of component (c) include succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, ethyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, ethylhexahydrophthalic anhydride, and itaconic anhydride. Among these, from the viewpoint of resolution, component (c) may be tetrahydrophthalic anhydride. Component (c) may be used alone or in combination of two or more.

[0064] If necessary, as component (a), for example, a hydrogenated bisphenol A epoxy resin may be used in combination, or a styrene-maleic acid-based resin such as a hydroxyethyl (meth)acrylate modified product of a styrene-maleic anhydride copolymer may be used in combination.

[0065] In the reaction between component (A') and component (c), for example, the acid value of the acid-modified vinyl group-containing resin can be adjusted by reacting 0.1 to 1.0 equivalents of component (c) with 1 equivalent of hydroxyl groups in component (A').

[0066] The acid value of component (A) may be 30 mg KOH / g or more, 40 mg KOH / g or more, or 50 mg KOH / g or more, from the viewpoint of improving the solubility of the photosensitive resin composition in an alkaline aqueous solution. The acid value of component (A) may be 200 mg KOH / g or less, 180 mg KOH / g or less, 150 mg KOH / g or less, or 100 mg KOH / g or less, from the viewpoint of improving the electrical properties of the permanent resist.

[0067] The acid value can be measured using the following procedure. First, 1 g of component (A), which is the substance to be measured for acid value, is accurately weighed, and then 30 g of acetone is added to component (A) to uniformly dissolve it and obtain a solution. Next, an appropriate amount of phenolphthalein, which is an indicator, is added to the solution, and then titration is performed using a 0.1 N KOH (potassium hydroxide) aqueous solution. The acid value is determined by calculating the mass (in mg) of KOH required to neutralize the acetone solution of component (A).

[0068] The weight-average molecular weight (Mw) of component (A) is not particularly limited. From the viewpoint of improving the adhesion, heat resistance, and insulation reliability of the permanent resist, the Mw of component (A) may be 1000 or more, 3000 or more, 4000 or more, or 5000 or more. From the viewpoint of improving the resolution of the photosensitive layer, the Mw of component (A) may be 30000 or less, 25000 or less, 18000 or less, or 15000 or less.

[0069] Mw can be measured by gel permeation chromatography (GPC). For example, Mw can be measured under the GPC conditions described below, and the value converted using a calibration curve for standard polystyrene can be used as the Mw value. A set of five samples ("PStQuick MP-H" and "PStQuick B," manufactured by Tosoh Corporation) can be used as the standard polystyrene to create the calibration curve. GPC instrument: High-speed GPC instrument "HCL-8320GPC" (manufactured by Tosoh Corporation) Detector: Differential refractometer or UV detector (manufactured by Tosoh Corporation) Column: TSKgel SuperMultipore HZ-H column (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 / THF 5 mL Injection volume: 20 μL

[0070] (A) The content of component (A) may be 5% by mass or more, 10% by mass or more, or 15% by mass or more, based on the total solid content of the photosensitive resin composition, from the viewpoint of heat resistance, electrical properties and chemical resistance of the permanent resist, and may be 50% by mass or less, 40% by mass or less, 35% by mass or less, or 30% by mass or less.

[0071] <Component (B): Photopolymerizable compound> The photosensitive resin composition according to this embodiment contains a photopolymerizable compound (excluding component (A) described above) as component (B). Component (B) is not particularly limited as long as it is a compound having a functional group that exhibits photopolymerizability. Examples of functional groups that exhibit photopolymerizability include groups having an ethylenically unsaturated bond, such as vinyl group, allyl group, propargyl group, butenyl group, ethynyl group, phenylethynyl group, maleimide group, nadiimide group, and (meth)acryloyl group.

[0072] (B) Component examples 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. Examples include polyhydric alcohols such as dipentaerythritol and tris-hydroxyethyl isocyanurate, or polyhydric (meth)acrylates of ethylene oxide or propylene oxide adducts thereof; (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 individually or in combination of two or more.

[0073] From the viewpoint of insulation reliability, component (B) may include a (meth)acrylic compound having (meth)acryloyl groups. The (meth)acrylic compound may be a monofunctional (meth)acrylic compound or a polyfunctional (meth)acrylic compound. A "monofunctional (meth)acrylic compound" means a compound in which the total number of acryloyl groups and methacryloyl groups in one molecule is 1, and a "polyfunctional (meth)acrylic compound" means a compound in which the total number of acryloyl groups and methacryloyl groups in one molecule is 2 or more.

[0074] (Meth)acrylic compounds may include tetrafunctional or higher (meth)acrylic compounds from the viewpoint of superior insulation reliability. Examples of tetrafunctional or higher (meth)acrylic compounds include pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, ethoxylated propoxylated pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethoxylated dipentaerythritol hexa(meth)acrylate, and propoxylated dipentaerythritol hexa(meth)acrylate.

[0075] The content of component (B) may be 1.0 to 15.0% by mass, 2.0 to 12.0% by mass, 4.0 to 10.0% by mass or more, 5.0 to 9.0% by mass, or 6.0 to 8.0% by mass, based on the total amount of solids in the photosensitive resin composition. When the content of component (B) is within the above range, the resolution can be further improved.

[0076] <Component (C): Thermosetting Resin> The photosensitive resin composition according to this embodiment contains a thermosetting resin as component (C). By including component (C) in the photosensitive resin composition, the insulation reliability, heat resistance, adhesion, and chemical resistance of the cured film (permanent resist) formed from the photosensitive resin composition can be improved. Component (C) may be used alone or in combination of two or more types.

[0077] Examples of component (C) 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. Among these, epoxy resin may be used as component (C) from the viewpoint of superior heat resistance, adhesion, and insulation reliability.

[0078] 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, novolac type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, hydantoin type epoxy resin, triglycidyl isocyanurate, and bixylenol type epoxy resin.

[0079] The content of component (C) may be 2.0 to 30.0% by mass, 5.0 to 25.0% by mass, 8.0 to 22.0% by mass, 10 to 20.0% by mass, or 12.0 to 18.0% by mass, based on the total solid content of the photosensitive resin composition. When the content of component (C) is within the above range, the insulation reliability and heat resistance of the formed cured film can be further improved while maintaining good developability.

[0080] <Component (D): Inorganic Filler> The photosensitive resin composition according to this embodiment contains an inorganic filler as component (D). By including component (D), the adhesive strength and hardness of the permanent resist can be improved. Component (D) may be used alone or in combination of two or more types.

[0081] Examples of inorganic fillers include silica, 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.

[0082] Component (D) may contain silica from the viewpoint of improving the heat resistance of the permanent resist, may contain barium sulfate from the viewpoint of improving the heat resistance and adhesive strength of the permanent resist, or may contain both silica and barium sulfate. From the viewpoint of improving the dispersibility of the inorganic filler, an inorganic filler that has been pre-surface-treated with alumina or an organosilane compound may be used.

[0083] The average particle size of the inorganic filler may be 0.01 to 5.0 μm, 0.05 to 3.0 μm, 0.1 to 2.0 μm, or 0.15 to 1.0 μm, from the viewpoint of resolution.

[0084] The average particle size of component (D) is the average particle size of the inorganic filler dispersed in the photosensitive resin composition, and is the value obtained by measurement as follows: First, the photosensitive resin composition is diluted 1000 times with methyl ethyl ketone, and then the particles dispersed in the solvent are measured using a submicron particle analyzer (Beckman Coulter, Inc., product name "N5") in accordance with the international standard ISO 13321, with a refractive index of 1.38, and the particle diameter at 50% of the cumulative value (by volume) in the particle size distribution is taken as the average particle size.

[0085] The content of component (D) may be 10 to 70% by mass, 20 to 60% by mass, 30 to 55% by mass, or 40 to 50% by mass, based on the total solid content of the photosensitive resin composition. Alternatively, the content of component (D) may be 50 to 200 parts by mass, 60 to 160 parts by mass, 70 to 140 parts by mass, or 80 to 120 parts by mass, based on 100 parts by mass of the total amount of components (A), (B), and (C). When the content of component (D) is within the above range, the low coefficient of thermal expansion, heat resistance, and film strength can be further improved.

[0086] <Component (E): Photopolymerization Initiator> The photosensitive resin composition according to this embodiment contains a photopolymerization initiator as component (E). Component (E) is not particularly limited as long as it can polymerize components (A) and (B). Component (E) may be used alone or in combination of two or more types.

[0087] Examples of component (E) include benzophenone-based photopolymerization initiators, alkylphenone-based photopolymerization initiators, alkylanthraquinone-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, oxime ester-based photopolymerization initiators, and acridine-based photopolymerization initiators. Component (E) can be selected according to the desired performance.

[0088] Examples of benzophenone-based photopolymerization initiators include benzophenone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bis(diethylamino)benzophenone (Michlars ketone), and 4-benzoyl-4'-methyldiphenyl sulfide.

[0089] Examples of alkylphenone-based photopolymerization initiators include benzyl ketals such as 2,2-dimethoxy-2-phenylacetophenone and 2,2-diethoxy-2-phenylacetophenone; α-hydroxyalkylphenones such as 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane, and 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-methylpropane; and α-aminoacetophenones such as 2-benzyl-2-dimethylamino-4'-morpholinobylophenone and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone.

[0090] Examples of alkylanthraquinone-based photopolymerization initiators include 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone.

[0091] Examples of thioxanthone-based photopolymerization initiators include 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone.

[0092] Examples of acylphosphine oxide-based photopolymerization initiators include 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0093] Examples of oxime ester-based photopolymerization initiators include 1,2-octanedione-1-[4-(phenylthio)phenyl]-2-(O-benzoyl oxime), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]ethanone 1-(O-acetyl oxime), and 1-phenyl-1,2-propanedione-2-[O-(ethoxycarbonyl)oxime].

[0094] Examples of acridine-based photopolymerization initiators include 9-phenylacridine and 1,7-bis(9,9'-acridinyl)heptane.

[0095] Component (E) may contain an alkylphenone-based photopolymerization initiator, a thioxanthone-based photopolymerization initiator, or an acylphosphine oxide-based photopolymerization initiator from the viewpoint of improving solder heat resistance. Component (E) may contain an acylphosphine oxide-based photopolymerization initiator from the viewpoint of improving the curability of the bottom by photobleaching, and may also contain an alkylphenone-based photopolymerization initiator from the viewpoint of being less prone to volatilization and outgassing. Component (E) may contain both an alkylphenone-based photopolymerization initiator and an acylphosphine oxide-based photopolymerization initiator.

[0096] The content of component (E) may be 0.5 to 5.0 parts by mass, 1.0 to 4.0 parts by mass, 1.5 to 3.5 parts by mass, or 2.0 to 3.0 parts by mass per 100 parts by mass of the total amount of components (A), (B), and (C). If the content of component (E) is 0.5 parts by mass or more, the exposed area will be less likely to dissolve during development, and if it is 5.0 parts by mass or less, the decrease in heat resistance will be more easily suppressed.

[0097] <Component (F): Polymerization inhibitor> The photosensitive resin composition contains a nitroxyl radical compound as component (F) from the viewpoint of forming openings with a good shape. As the nitroxyl radical compound, a 2,2,6,6-tetramethylpiperidine-1-oxyl derivative can be used. Component (F) may be used alone or in combination of two or more.

[0098] Examples of nitroxyl radical compounds include 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical, 4-carboxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical, 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl free radical, 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxyl free radical, and 4-(2-chloroacetamide)-2,2,6,6-tetramethylpiperidine-1-oxyl free radical. Examples include xyl free radicals, 4-cyano-2,2,6,6-tetramethylpiperidine-1-oxyl free radicals, 4-methyl-2,2,6,6-tetramethylpiperidine-1-oxyl free radicals, 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radicals, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radicals, and 4-acetyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radicals.

[0099] From the viewpoint of reducing undercuts at the opening, the content of the nitroxyl radical compound is 0.015 to 0.40 parts by mass, preferably 0.020 to 0.35 parts by mass, more preferably 0.025 to 0.30 parts by mass, and even more preferably 0.030 to 0.28 parts by mass, based on 100 parts by mass of the total amount of (A) acid-modified vinyl group-containing resin, (B) photopolymerizable compound, and (C) thermosetting resin.

[0100] From the viewpoint of further reducing undercutting of the opening, the content of the nitroxyl radical compound may be 0.031 to 0.50 parts by mass, 0.035 to 0.48 parts by mass, 0.040 to 0.45 parts by mass, or 0.042 to 0.40 parts by mass per 100 parts by mass of the total amount of component (A) and component (B).

[0101] The content of component (F) may be 0.005 to 1.0% by mass, 0.008 to 0.50% by mass, 0.010 to 0.20% by mass, or 0.012 to 0.15% by mass, based on the total solid content of the photosensitive resin composition, from the viewpoint of forming an opening with a better shape.

[0102] Component (F) may further contain other polymerization inhibitors other than nitroxyl radical compounds, provided that they do not impede the effects of the present disclosure. Examples of other polymerization inhibitors include catechol compounds (e.g., tert-butylcatechol) and phenolic antioxidants.

[0103] <Component (G): Pigment> The photosensitive resin composition according to this embodiment may further contain a pigment as component (G) from the viewpoint of improving the identifiability or appearance of the manufacturing apparatus. As component (G), a coloring agent that produces a desired color when concealing wiring (conductor patterns) can be used. Component (G) may be used alone or in combination of two or more types.

[0104] Examples of component (G) include phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium dioxide, carbon black, and naphthalene black.

[0105] (G) The content of component (G) may be 0.01 to 5.0% by mass, 0.03 to 3.0% by mass, or 0.05 to 2.0% by mass, based on the total amount of solids in the photosensitive resin composition, from the viewpoint of making the manufacturing equipment easier to identify and better concealing the wiring.

[0106] <Other Components> The photosensitive resin composition according to this embodiment may be further mixed with various additives as needed. Examples of additives include silane coupling agents; curing accelerators such as melamine; thickeners such as bentonite and montmorillonite; defoaming agents such as silicone-based, fluorine-based, and vinyl resin-based agents; and flame retardants such as phosphorus-based phosphate compounds, aromatic condensed phosphate esters, and halogen-containing condensed phosphate esters. These may be used individually or in combination of two or more.

[0107] The photosensitive resin composition according to this embodiment may be mixed with a diluent such as an organic solvent to adjust its viscosity. Examples of organic 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; and esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, and carbitol acetate.

[0108] When a diluent is used, the content of the diluent in the photosensitive resin composition may be 10 to 50% by mass, 20 to 40% by mass, or 25 to 35% by mass. By setting the content of the diluent within the above ranges, the coatability of the photosensitive resin composition is improved.

[0109] The photosensitive resin composition according to this embodiment can be prepared by uniformly mixing the above-mentioned components using a roll mill, bead mill, or the like.

[0110] [Photosensitive Element] The photosensitive element according to this embodiment comprises a support film and a photosensitive layer containing the above-described photosensitive resin composition. Figure 1 is a schematic cross-sectional view showing the photosensitive element according to this embodiment. As shown in Figure 1, the photosensitive element 1 comprises a support film 10 and a photosensitive layer 20 formed on the support film 10. The solid content of each component other than volatile substances in the photosensitive layer 20 may be within the numerical range of the solid content of each component in the above-described photosensitive resin composition.

[0111] The photosensitive element 1 can be manufactured, for example, by applying the photosensitive resin composition according to this embodiment onto the support film 10 using 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.

[0112] Examples of support films 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. The thickness of the photosensitive layer may be, for example, 10 to 50 μm, 15 to 40 μm, or 20 to 30 μm.

[0113] The coating film can be dried using hot air drying, far-infrared radiation, or near-infrared radiation. The drying temperature may be 60-120°C, 70-110°C, or 80-100°C. The drying time may be 1-60 minutes, 2-30 minutes, or 3-20 minutes.

[0114] A protective film 30 covering the photosensitive layer 20 may be further provided on the photosensitive layer 20. The protective film 30 of the photosensitive element 1 can also be laminated on the side of the photosensitive layer 20 opposite to the side in contact with the support film 10. As the protective film 30, for example, a polymer film such as polyethylene or polypropylene may be used. The protective film may be the same film as the support film, or it may be a different film.

[0115] [Printed Wiring Board] The printed wiring board according to this embodiment comprises a permanent resist containing a cured product of the photosensitive resin composition according to this embodiment.

[0116] The method for manufacturing a printed circuit board according to this embodiment comprises the steps of: forming a photosensitive layer on a substrate using the above-mentioned 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.

[0117] First, a core substrate with copper wiring formed on it is prepared as the substrate, and a photosensitive layer is formed on the substrate. When using a photosensitive resin composition, the photosensitive resin composition may be applied to the substrate by methods such as screen printing, spraying, roll coating, curtain coating, or electrostatic coating, and the formed coating film may be dried at 60 to 110°C to form the photosensitive layer. The thickness of the coating film may be 10 to 200 μm, 15 to 150 μm, 20 to 100 μm, or 23 to 50 μm. When using a photosensitive element, the photosensitive layer may be formed by thermal laminating the photosensitive layer of the photosensitive element onto the substrate using a laminator.

[0118] Next, by irradiating at least a portion of the photosensitive layer with active light, the irradiated portion becomes photocured, and a latent image is formed. In this case, if a support is present on the photosensitive layer, if the support is transparent to the active light, the active light can be irradiated through the support. However, if the support is light-blocking, the support is removed before irradiating the photosensitive layer with active light.

[0119] Exposure methods include, for example, direct imaging exposure methods such as LDI (Laser Direct Imaging) exposure and DLP (Digital Light Processing) exposure, which involve irradiating an active ray in an image-like manner; methods of irradiating an active ray in an image-like manner via a negative mask pattern (mask exposure method); and methods of irradiating an active ray in an image-like manner via projection exposure. Examples of active rays include electron beams, ultraviolet rays, and X-rays. 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 / cm². ２ , 20-1500mJ / cm ２ , 30-1000mJ / cm ２ , or 40-500 mJ / cm² ２ That's fine.

[0120] After exposure, the unexposed areas are dissolved and removed with a developer to form a resist pattern. Examples of development methods include dipping and spraying. Suitable developers include alkaline aqueous solutions such as potassium hydroxide aqueous solution, sodium hydroxide aqueous solution, sodium carbonate aqueous solution, potassium carbonate aqueous solution, and tetramethylammonium hydroxide aqueous solution.

[0121] Next, the formed resist pattern can be sufficiently cured by at least one of post-exposure and post-heating to form a permanent resist with openings. The exposure amount for post-exposure is 100 to 5000 mJ / cm². ２ , 500-3000mJ / cm ２ , or 700-2000 mJ / cm ２ The heating temperature for post-heating may be 100-200°C, 120-190°C, or 135-180°C. The heating time for post-heating may be 5 minutes to 6 hours, 10 minutes to 3 hours, or 30 minutes to 2 hours. The thickness of the permanent resist may be 10-50 μm, 15-40 μm, or 20-30 μm.

[0122] Figure 2 is a schematic cross-sectional view showing the NSMD structure in a printed circuit board. As shown in Figure 2, by using the photosensitive resin composition according to this embodiment, a permanent resist 70 having openings 60 can be formed on a core substrate 50 on which copper wiring 40 is formed.

[0123] The permanent resist according to this embodiment can be used as an interlayer insulating layer or surface protective layer of a semiconductor element. A semiconductor element having an interlayer insulating layer or surface protective layer formed from the cured film of the above-described photosensitive resin composition, and an electronic device including the semiconductor element, can be manufactured. The semiconductor element may be, for example, a memory, package, etc., having a multilayer wiring structure, a rewiring structure, etc. Examples of electronic devices include mobile phones, smartphones, tablet terminals, personal computers, and hard disk suspensions.

[0124] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0125] (Synthesis of component (A-1)) 350 parts by mass of bisphenol F novolac type epoxy resin (manufactured by DIC Corporation, trade name "EXA-7376"), 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 mixture was cooled to 60°C, 2 parts by mass of triphenylphosphine were added, and the mixture was reacted at 100°C until the acid value of the solution was 1 mg KOH / g or less. To the reaction solution, 98 parts by mass of tetrahydrophthalic anhydride (THPAC) and 85 parts by mass of carbitol acetate were added, and the mixture was reacted at 80°C for 6 hours. The reaction solution was then cooled to room temperature to obtain a solution of THPAC-modified bisphenol F type cresol novolac epoxy acrylate as component (A-1) (solid content concentration: 73% by mass).

[0126] (Examples 1-3 and Comparative Examples 1-3) [Photosensitive Resin Composition] Each component was blended in the amounts (parts by mass, equivalent to solid content) shown in Table 1 below and kneaded in a three-roll mill. Then, methyl ethyl ketone was added to obtain a photosensitive resin composition so that the solid content concentration was 65% by mass. Details of each component shown in Table 1 are as follows.

[0127] ((A) Acid-modified vinyl group-containing resin) A-1: ​​Component (A-1) synthesized above ((B) Photopolymerizable compound) B-1: DPHA (a mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate, manufactured by Nippon Kayaku Co., Ltd., trade name "KAYARAD DPHA") ((C) Thermosetting resin) C-1: Bisphenol F type epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., trade name "YSLV-80XY") C-2: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name "YL980") ((D) Inorganic filler) D-1: Silica particles (manufactured by Admatex Co., Ltd., trade name "SC2500", average particle size: 0.5 μm) ((E) Photopolymerization initiator) E-1: 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone (manufactured by IGM Resins B.V., trade name "Omnirad 907", alkylphenone-based photopolymerization initiator) E-2: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (manufactured by IGM Resins B.V., trade name "Omnirad 819", acylphosphine oxide-based photopolymerization initiator) ((F) polymerization inhibitor) F-1: 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical (manufactured by Tokyo Chemical Industry Co., Ltd., nitroxyl radical compound) F-2: 4-t-butylcatechol (manufactured by DIC Corporation, trade name "DIC-TBC", catechol compound) F-3: 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane (ADEKA Corporation, product name "ADEKA Stab AO-80", phenolic antioxidant) ((G) Pigment) G-1: Phthalocyanine pigment: Manufactured by Sanyo Shikkei Co., Ltd.

[0128] [Preparation of Photosensitive Element] A 25 μm thick polyethylene terephthalate film (manufactured by Toyobo Film Solutions Co., Ltd., product name "G2-25") was prepared as a support film. The photosensitive resin compositions of the examples and comparative examples were uniformly applied to the support film so that the film thickness after drying was 25 μm, and dried at 75°C for 15 minutes using a hot air convection dryer to form a photosensitive layer. Subsequently, a polyethylene film (manufactured by Tamapoly Co., Ltd., product name "NF-15") was laminated as a protective film onto the surface opposite to the side of the photosensitive layer that is in contact with the support film, and a photosensitive element was prepared.

[0129] [Preparation of Evaluation Laminate] A 0.4 mm thick copper-clad laminate substrate (manufactured by Resonac Co., Ltd., product name "MCL-E-705G") was prepared by laminating copper foil on both sides of a glass epoxy substrate. The copper foil on both sides of the copper-clad laminate substrate was removed using a known etching method to obtain the glass epoxy substrate. Next, the protective film was peeled off from the photosensitive element, and the exposed photosensitive layer was placed on the glass epoxy substrate. Then, lamination was performed using a press-type vacuum laminator (manufactured by Meiki Seisakusho Co., Ltd., product name "MVLP-500"). The lamination conditions were: vacuuming time 40 seconds, atmospheric pressure 4 kPa or less, press hot plate temperature 80°C, pressing pressure 0.4 MPa, and lamination press time 20 seconds. After lamination, it was left at room temperature for 1 hour to obtain an evaluation laminate in which the photosensitive layer and support film were laminated on the glass epoxy substrate in that order.

[0130] (Undercut evaluation) Exposure of 50-300 mJ / cm² was performed using an i-line exposure system (manufactured by Ushio Inc., product name "UX-2240SM") via a negative mask with a via pattern (aperture diameter size: 100 μmφ) on the support film of the evaluation laminate. ２ Within the range of 50 mJ / cm ２ The exposure was gradually changed. After exposure, the film was left at room temperature for 30 minutes, then the support film was peeled off, and the photosensitive layer was spray-developed using a 1% by mass sodium carbonate aqueous solution to remove the unexposed areas. The development conditions were: development time equivalent to twice the shortest development time at 30°C (the shortest time for removing the unexposed areas of the photosensitive layer), and spray pressure of 1.765 × 10⁻⁶. ５The exposure pressure was set to Pa. Next, using an ultraviolet exposure apparatus (manufactured by Oak Manufacturing Co., Ltd., product name "QRM-2317"), the photosensitive layer after development was exposed to 2000 mJ / cm². ２ Test specimens were prepared on a glass epoxy substrate by exposing it to a certain exposure level and heating it at 170°C for 1 hour, resulting in a cured film (permanent resist) with 100 μmφ openings.

[0131] The above test specimens were cast with embedding resin (using Mitsubishi Chemical Corporation's product name "jER828" as the epoxy resin, with triethylenetetramine as the curing agent) and allowed to cure completely. After that, they were polished with a polishing machine (Refinetech Co., Ltd., product name "Refine Polisher") to remove the cross-section of the opening pattern of the permanent mask resist. The resulting cross-section of the opening pattern was observed using a metallurgical microscope, and the undercut was evaluated according to the following criteria. The results are shown in Table 1. A: Undercut of 5.0 μm or less. B: Undercut greater than 5.0 μm and 8.0 μm or less. C: Undercut greater than 8.0 μm and less than 11.0 μm. D: Undercut of 11.0 μm or more.

[0132]

[0133] 1...Photosensitive element, 10...Support film, 20...Photosensitive layer, 30...Protective film, 40...Copper wiring, 50...Core substrate, 60...Opening, 70...Permanent resist.

Claims

1. A photosensitive resin composition for permanent resists, comprising (A) an acid-modified vinyl group-containing resin, (B) a photopolymerizable compound, (C) a thermosetting resin, (D) an inorganic filler, (E) a photopolymerization initiator, and (F) a polymerization inhibitor, wherein the polymerization inhibitor (F) contains a nitroxyl radical compound, and the content of the nitroxyl radical compound is 0.015 to 0.40 parts by mass per 100 parts by mass of the total amount of (A) the acid-modified vinyl group-containing resin, (B) the photopolymerizable compound, and (C) the thermosetting resin.

2. The photosensitive resin composition according to claim 1, wherein the nitroxyl radical compound is a 2,2,6,6-tetramethylpiperidine-1-oxyl derivative.

3. The photosensitive resin composition according to claim 1, wherein the content of the nitroxyl radical compound is 0.025 to 0.30 parts by mass per 100 parts by mass of the total amount of (A) acid-modified vinyl group-containing resin, (B) photopolymerizable compound, and (C) thermosetting resin.

4. The photosensitive resin composition according to claim 1, wherein the (A) acid-modified vinyl group-containing resin comprises an acid-modified bisphenol novolac type epoxy (meth)acrylate.

5. The photosensitive resin composition according to claim 1, wherein the (E) photopolymerization initiator comprises an alkylphenone-based photopolymerization initiator and an acylphosphine oxide-based photopolymerization initiator.

6. The photosensitive resin composition according to claim 1, wherein the content of the nitroxyl radical compound is 0.031 to 0.50 parts by mass per 100 parts by mass of the total amount of (A) acid-modified vinyl group-containing resin and (B) photopolymerizable compound.

7. The photosensitive resin composition according to claim 1, used for forming openings in an NSMD structure.

8. A photosensitive element comprising a support film and a photosensitive layer formed on the support film, wherein the photosensitive layer contains the photosensitive resin composition according to any one of claims 1 to 7.

9. A printed circuit board comprising a permanent resist containing a cured product of the photosensitive resin composition according to any one of claims 1 to 7.

10. A method for manufacturing a printed circuit board, comprising the steps of: forming a photosensitive layer on a substrate using a photosensitive resin composition according to any one of claims 1 to 7; exposing and developing the photosensitive layer to form a resist pattern; and curing the resist pattern to form a permanent resist.

11. A method for manufacturing a printed circuit board, comprising the steps of: forming a photosensitive layer on a substrate using the photosensitive element described in claim 8; exposing and developing the photosensitive layer to form a resist pattern; and curing the resist pattern to form a permanent resist.

Images