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

Abstract

To provide a photosensitive resin composition containing a carboxyl group-containing resin, which facilitates achieving a low dielectric loss tangent in a cured product, allows the flexibility of the cured product to be easily maintained, and is resistant to excessive corrosion even when the cured product is treated with an oxidizing agent.SOLUTION: A photosensitive resin composition contains a carboxyl group-containing resin (A), a photopolymerization initiator (B), a photopolymerizable compound (C), an epoxy compound (D), silica (E) whose percentage relative to the carboxyl group-containing resin (A) is 50 mass% or more and 300 mass% or less, the silica (E) being surface-treated with a silane coupling agent, and a blocked isocyanate compound (F) whose percentage relative to the carboxyl group-containing resin (A) is 21 mass% or more and 100 mass% or less. The silane coupling agent has a phenyl skeleton.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a photosensitive resin composition, a dry film, a cured product, and a printed circuit board, and more specifically, to a photosensitive resin composition containing a carboxyl group-containing resin, a dry film containing the photosensitive resin composition, a cured product of the photosensitive resin composition, and a printed circuit board comprising a solder resist layer or interlayer insulating layer containing the cured product. [Background technology]

[0002] Patent Document 1 discloses a curable resin composition in which the cured product has a low dielectric constant and a low dielectric loss tangent. Patent Document 1 also discloses that the curable resin composition contains an alkali-soluble resin, an inorganic filler, a photocurable compound that does not have hydroxyl groups and carboxyl groups, an adhesion promoter, and a photopolymerization initiator, that a blocked isocyanate is preferred as the adhesion promoter, and that the amount of adhesion promoter added is 0.01 to 20 parts by mass per 100 parts by mass of (A) alkali-soluble resin, on a solid content basis. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2017-68242 [Overview of the project] [Problems that the invention aims to solve]

[0004] According to the inventor's own findings obtained through research and development, when preparing solder resist layers, interlayer insulating layers, etc., from cured resin compositions containing carboxyl group-containing resins, the addition of inorganic fillers to reduce dielectric loss tangent tends to make the cured material brittle. Furthermore, when the surface of the cured material is treated with an oxidizing agent to adjust its roughness in order to improve adhesion between the cured material, particularly the interlayer insulating layer and the conductor overlapping it, the inorganic fillers tend to detach from the cured material, making it susceptible to excessive corrosion by the oxidizing agent.

[0005] The object of the present invention is to provide a photosensitive resin composition containing a carboxyl group-containing resin that makes it easy to achieve a low dielectric loss tangent in the cured product, makes it easy to maintain the flexibility of the cured product, and makes the cured product less susceptible to excessive corrosion even when treated with an oxidizing agent; a dry film containing this photosensitive resin composition; a cured product of this photosensitive resin composition; and a printed circuit board comprising a solder resist layer or interlayer insulating layer containing this cured product. [Means for solving the problem]

[0006] A photosensitive resin composition according to one aspect of the present invention contains a carboxyl group-containing resin (A), a photopolymerization initiator (B), a photopolymerizable compound (C), an epoxy compound (D), silica (E) in a ratio of 50% to 300% by mass relative to the carboxyl group-containing resin (A), and a blocked isocyanate compound (F) in a ratio of 21% to 100% by mass relative to the carboxyl group-containing resin (A).

[0007] A dry film according to one aspect of the present invention contains the photosensitive resin composition.

[0008] A cured product according to one aspect of the present invention is obtained by curing the photosensitive resin composition.

[0009] A printed circuit board according to one aspect of the present invention comprises an interlayer insulating layer containing the cured material.

[0010] A printed circuit board according to one aspect of the present invention comprises a solder resist layer containing the cured product. [Effects of the Invention]

[0011] According to one aspect of the present invention, a photosensitive resin composition containing a carboxyl group-containing resin is provided, which easily reduces the dielectric loss tangent of the cured product, easily maintains the flexibility of the cured product, and is resistant to excessive corrosion even when the cured product is treated with an oxidizing agent; a dry film containing this photosensitive resin composition; a cured product of this photosensitive resin composition; and a printed wiring board comprising a solder resist layer or interlayer insulating layer containing this cured product. [Brief explanation of the drawing]

[0012] [Figure 1] Figures 1A to 1E are cross-sectional views showing the process for manufacturing a printed circuit board according to one embodiment of the present invention. [Modes for carrying out the invention]

[0013] One embodiment of the present invention will be described below. Note that the following embodiment is only one of many embodiments of the present invention. The following embodiment can be modified in various ways depending on the design, as long as the objective of the present invention is achieved.

[0014] The photosensitive resin composition according to this embodiment contains a carboxyl group-containing resin (A), a photopolymerization initiator (B), a photopolymerizable compound (C), an epoxy compound (D), silica (E) in a ratio of 50% to 300% by mass relative to the carboxyl group-containing resin (A), and a blocked isocyanate compound (F) in a ratio of 21% to 100% by mass relative to the carboxyl group-containing resin (A).

[0015] According to this embodiment, the dielectric loss tangent of the cured product of the photosensitive resin composition is easily reduced. Therefore, the high-frequency characteristics of the printed circuit board containing the cured product of the photosensitive resin composition are easily improved. Furthermore, the flexibility of the cured product is easily maintained, and the cured product is less susceptible to excessive corrosion even when treated with an oxidizing agent. The reasons for this are presumed to be as follows. However, this embodiment is not bound by the explanation of the reasons below.

[0016] The photosensitive resin composition contains silica (E), and the percentage of silica (E) to carboxyl group-containing resin (A) is 50% by mass or more, so that silica (E) can reduce the dielectric loss tangent of the cured product. Furthermore, the photosensitive resin composition contains a blocked isocyanate compound (F), and the percentage of the blocked isocyanate compound (F) is 21% by mass or more and 100% by mass or less relative to the carboxyl group-containing resin (A), so that during the curing process of the photosensitive resin composition, the blocked isocyanate compound (F) reacts with hydroxyl groups, thereby reducing the hydroxyl groups in the cured product (X), and further reducing the dielectric loss tangent of the cured product. In addition, the urethane bonds formed by this reaction enhance the flexibility of the cured product. Moreover, the blocked isocyanate compound (F) readily bonds with the hydroxyl groups on the surface of silica (E), so that even if the surface of the cured product is treated with an oxidizing agent, the silica (E) particles are less likely to detach from the cured product.

[0017] Furthermore, the blocked isocyanate compound (F) can improve the developability when producing films such as solder resist layers and interlayer insulating layers from a photosensitive resin composition by photolithography. Although the reason for this is not entirely clear, it is presumed that when the percentage of the blocked isocyanate compound (F) in the photosensitive resin composition is 21% to 100% by mass relative to the carboxyl group-containing resin (A), the blocked isocyanate compound (F) acts as a plasticizer, making the photosensitive resin composition more compatible with developing solutions such as alkaline aqueous solutions. This allows the photosensitive resin composition to dissolve or disperse appropriately in the developing solution. In addition, since the blocked isocyanate compound (F) is protected by a blocking agent, it is less likely to react during the film formation process by photolithography. This is also presumed to contribute to the improved developability.

[0018] The components of the photosensitive resin composition will be explained in more detail.

[0019] The carboxyl group-containing resin (A) can contain a component having a carboxyl group with an ethylenically unsaturated group. In this case, the carboxyl group-containing resin (A) can impart photosensitivity, specifically photocurability, to the photosensitive resin composition.

[0020] The carboxyl group-containing resin (A) preferably contains a carboxyl group-containing resin (A1) having an aromatic ring. In this case, the heat resistance and electrical insulation of the cured product of the photosensitive resin composition are likely to be enhanced. The carboxyl group-containing resin (A1) more preferably has any one of a polycyclic aromatic ring of a biphenyl skeleton, a naphthalene skeleton, a fluorene skeleton, and an anthracene skeleton. In this case, the heat resistance and electrical insulation of the cured product are more likely to be enhanced.

[0021] The carboxyl group-containing resin (A) particularly preferably contains a carboxyl group-containing resin (A11) having a bisphenol fluorene skeleton. In this case, the heat resistance and electrical insulation of the cured product are particularly likely to be enhanced.

[0022] The bisphenol fluorene skeleton is represented by the following formula (1).

[0023]

Chemical formula

[0024] In formula (1), R1 to R8 are each independently hydrogen, an alkyl group having 1 to 5 carbon atoms, or a halogen. That is, each of R1 to R8 in formula (1) may be hydrogen, but may also be an alkyl group having 1 to 5 carbon atoms or a halogen. Even if the hydrogen in the aromatic ring is substituted with a low molecular weight alkyl group or a halogen, it does not adversely affect the physical properties of the carboxyl group-containing resin (A11), but rather, in some cases, the heat resistance or flame retardancy of the cured product of the photosensitive resin composition containing the carboxyl group-containing resin (A11) is improved by the substitution.

[0025] The carboxyl group-containing resin (A11) can be synthesized, for example, by reacting an epoxy compound (a1) having a bisphenol fluorene skeleton represented by formula (1) with an unsaturated group-containing carboxylic acid (a2), and then reacting the resulting intermediate with an acid anhydride (a3).

[0026] The epoxy compound (a1) has a structure as shown in formula (2) below, for example. In formula (2), n is an integer in the range of 0 to 20. In order to appropriately control the molecular weight of the carboxyl group-containing resin (A11), it is more preferable that the average of n is in the range of 0 to 1. If the average of n is in the range of 0 to 1, an excessive increase in the molecular weight of the carboxyl group-containing resin (A11) is easily suppressed. Also, in formula (2), R1 to R8 are each independently hydrogen, an alkyl group having 1 to 5 carbon atoms, or a halogen.

[0027] [ka]

[0028] Unsaturated group-containing carboxylic acids (a2) include, for example, compounds that have only one ethylenically unsaturated group in a single molecule. More specifically, the unsaturated group-containing carboxylic acid (a2) contains, for example, at least one compound selected from the group consisting of acrylic acid, methacrylic acid, ω-carboxy-polycaprolactone (n≒2) monoacrylate, crotonic acid, cinnamic acid, 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl phthalic acid, 2-acryloyloxypropyl phthalic acid, 2-methacryloyloxypropyl phthalic acid, 2-acryloyloxyethyl maleic acid, 2-methacryloyloxyethyl maleic acid, β-carboxyethyl acrylate, 2-acryloyloxyethyl tetrahydrophthalic acid, 2-methacryloyloxyethyl tetrahydrophthalic acid, 2-acryloyloxyethyl hexahydrophthalic acid, and 2-methacryloyloxyethyl hexahydrophthalic acid. Preferably, the unsaturated group-containing carboxylic acid (a2) contains acrylic acid. Furthermore, if the unsaturated group-containing carboxylic acid (a2) contains acrylic acid, it is preferable that the acrylic acid is present in 50 mol% or more of the unsaturated group-containing carboxylic acid (a2), more preferably 80 mol% or more, even more preferably 85 mol% or more, and particularly preferably 90 mol% or more.

[0029] The epoxy compound (a1) and the unsaturated group-containing carboxylic acid (a2) can be reacted by appropriate methods. For example, a reactive solution can be obtained by adding the unsaturated group-containing carboxylic acid (a2) to a solvent solution of the epoxy compound (a1), and then, if necessary, adding a thermal polymerization inhibitor and a catalyst and stirring and mixing. An intermediate can be obtained by reacting this reactive solution by conventional methods at a temperature preferably between 60°C and 150°C, more preferably between 80°C and 120°C. The solvent in this case can contain at least one component selected from the group consisting of ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, and acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, and dialkyl glycol ethers. The thermal polymerization inhibitor may contain at least one component selected from the group consisting of, for example, hydroquinone, methylhydroquinone, and hydroquinone monomethyl ether. The catalyst may contain at least one component selected from the group consisting of, for example, tertiary amines such as benzyldimethylamine and triethylamine, quaternary ammonium salts such as trimethylbenzylammonium chloride and methyltriethylammonium chloride, triphenylphosphine, and triphenylstybin.

[0030] It is preferable that the catalyst contains triphenylphosphine. That is, it is preferable to react the epoxy compound (a1) with the unsaturated group-containing carboxylic acid (a2) in the presence of triphenylphosphine. In this case, the ring-opening addition reaction between the epoxy group in the epoxy compound (a1) and the unsaturated group-containing carboxylic acid (a2) is particularly promoted, and a reaction rate (conversion rate) of 95% or more, 97% or more, or nearly 100% can be achieved.

[0031] It is also preferable to react the epoxy compound (a1) with the unsaturated group-containing carboxylic acid (a2) under air bubbling. In this case, the addition polymerization reaction of the unsaturated group can be suppressed, thereby preventing an increase in the molecular weight of the intermediate and gelation of the intermediate solution. Furthermore, excessive discoloration of the final product, the carboxyl group-containing resin (A11), can be suppressed.

[0032] When reacting epoxy compound (a1) with unsaturated group-containing carboxylic acid (a2), the amount of unsaturated group-containing carboxylic acid (a2) per mole of epoxy group in epoxy compound (a1) is preferably 0.8 moles or more and 1.2 moles or less. In this case, a photosensitive resin composition with excellent photosensitivity and stability can be obtained.

[0033] The intermediate thus obtained comprises a hydroxyl group produced by the reaction between the epoxy group of the epoxy compound (a1) and the carboxyl group of the unsaturated group-containing carboxylic acid (a2).

[0034] Next, the intermediate is reacted with acid anhydride (a3). Acid anhydride (a3) ​​contains, for example, acid dianhydride (a4).

[0035] Acidic dianhydride (a4) is a compound having two acid anhydride groups. Acidic dianhydride (a4) can contain tetracarboxylic anhydrides. Examples of acidic dianhydride (a4) include 1,2,4,5-benzenetetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride, methylcyclohexene tetracarboxylic dianhydride, tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, ethylene tetracarboxylic dianhydride, 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride, glycerin bis-anhydrotrimellitate monoacetate, and ethylene The composition may contain at least one compound selected from the group consisting of glycol bis-anhydrotrimellitate, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-c]furan-1,3-dione, 1,2,3,4-butanetetracarboxylic dianhydride, and 3,3',4,4'-biphenyltetracarboxylic dianhydride. In particular, it is preferable that the acid dianhydride (a4) contains 3,3',4,4'-biphenyltetracarboxylic dianhydride. In this case, the photosensitive resin composition can suppress the tackiness of the film produced from the photosensitive resin composition while ensuring good developability, and can also improve the insulation reliability and plating resistance of the cured product.

[0036] Acid anhydride (a3) ​​may contain acid monoanhydride (a5). Acid monoanhydride (a5) is a compound having one acid anhydride group. Acid monoanhydride (a5) can contain dicarboxylic acid anhydrides. Acid monoanhydride (a5) can contain one or more compounds selected from the group consisting of, for example, phthalic anhydride, 1,2,3,6-tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, methylsuccinic anhydride, maleic anhydride, citraconic anhydride, glutaric anhydride, cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, and itaconic anhydride. It is particularly preferable that acid monoanhydride (a5) contains 1,2,3,6-tetrahydrophthalic anhydride. In other words, it is preferable that the acid anhydride (a3) ​​contains 1,2,3,6-tetrahydrophthalic anhydride. In this case, while ensuring good developability of the photosensitive resin composition, the tackiness of the film formed from the photosensitive resin composition can be further suppressed, and the insulation reliability and plating resistance of the cured product can be further improved. The amount of 1,2,3,6-tetrahydrophthalic anhydride relative to the total acid anhydride (a5) is preferably in the range of 20 mol% to 100 mol%, and more preferably in the range of 40 mol% to 100 mol%, but is not limited thereto.

[0037] Various methods can be used to react the intermediate with the acid anhydride (a3). For example, a reactive solution is obtained by adding the acid anhydride (a3) ​​to a solvent solution of the intermediate, and then, if necessary, adding a thermal polymerization inhibitor and a catalyst and stirring. By reacting this reactive solution at a temperature of 60°C to 150°C, more preferably 80°C to 120°C, a carboxyl group-containing resin (A11) having a bisphenol fluorene skeleton is obtained. Suitable solvents, catalysts, and polymerization inhibitors can be used, and the solvents, catalysts, and polymerization inhibitors used in the synthesis of the intermediate can also be used as is.

[0038] It is preferable that the catalyst contains triphenylphosphine. That is, it is preferable to react the intermediate with the acid anhydride (a3) ​​in the presence of triphenylphosphine. In this case, the reaction between the intermediate and the acid anhydride (a3) ​​is particularly promoted, and a reaction rate (conversion rate) of 90% or more, 95% or more, 97% or more, or nearly 100% can be achieved.

[0039] When the acid anhydride (a3) ​​contains an acid dianhydride (a4), the amount of acid dianhydride (a4) per mole of epoxy group of epoxy compound (a1) is preferably 0.05 moles or more and 0.24 moles or less. In this case, a carboxyl group-containing resin (A11) having a bisphenol fluorene skeleton with appropriately adjusted acid value and molecular weight can be easily obtained.

[0040] Furthermore, if the acid anhydride (a3) ​​further contains an acid monoanhydride (a5), it is preferable that the amount of acid monoanhydride (a5) is 0.3 moles or more and 0.7 moles or less per mole of epoxy groups of the epoxy compound (a1). In this case, a carboxyl group-containing resin (A11) having a bisphenol fluorene skeleton with appropriately adjusted acid value and molecular weight can be easily obtained.

[0041] It is also preferable to react the intermediate with the acid anhydride (a3) ​​under air bubbling. In this case, excessive molecular weight increase of the resulting carboxyl group-containing resin (A11) having a bisphenol fluorene skeleton is suppressed, which particularly improves the developability of the photosensitive resin composition with an alkaline aqueous solution.

[0042] The carboxyl group-containing resin (A) may also contain a carboxyl group-containing resin that does not have a bisphenol fluorene skeleton (hereinafter also referred to as carboxyl group-containing resin (A2)). The carboxyl group-containing resin (A) may contain at least one of the carboxyl group-containing resin (A11) and the carboxyl group-containing resin (A2).

[0043] The carboxyl group-containing resin (A2) may contain, for example, a carboxyl group-containing resin that has carboxyl groups and does not exhibit photopolymerization properties (hereinafter referred to as carboxyl group-containing resin (A2-1)). The carboxyl group-containing resin (A2-1) may contain, for example, a polymer of an ethylenically unsaturated monomer containing an ethylenically unsaturated compound having carboxyl groups. The ethylenically unsaturated compound having carboxyl groups may include compounds such as acrylic acid, methacrylic acid, and ω-carboxy-polycaprolactone (n≒2) monoacrylate. The ethylenically unsaturated compound having carboxyl groups may also include reaction products of pentaerythritol triacrylate, pentaerythritol trimethacrylate, etc., with dibasic acid anhydrides. The ethylenically unsaturated monomer may further contain ethylenically unsaturated compounds that do not have a carboxyl group, such as 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate, and (meth)acrylic acid esters of linear or branched aliphatic or alicyclic groups (which may have some unsaturated bonds in the ring).

[0044] The carboxyl group-containing resin (A2) may contain a carboxyl group-containing resin having a carboxyl group and an ethylenically unsaturated group (hereinafter referred to as carboxyl group-containing resin (A2-2)). The carboxyl group-containing resin (A2-2) can impart photosensitivity, specifically photocurability, to the photosensitive resin composition. The carboxyl group-containing resin (A2) may contain only the carboxyl group-containing resin (A2-2).

[0045] The carboxyl group-containing resin (A2-2) contains a resin (hereinafter also referred to as the first resin (x)) which is a reaction product of an intermediate that is a reaction product of an epoxy compound (x1) having two or more epoxy groups in one molecule and an ethylenically unsaturated compound (x2), and at least one compound (x3) selected from the group of polycarboxylic acids and their anhydrides. The first resin (x) is obtained, for example, by adding compound (x3) to an intermediate obtained by reacting the epoxy group in the epoxy compound (x1) with the carboxyl group in the ethylenically unsaturated compound (x2).

[0046] The epoxy compound (x1) may contain any suitable epoxy compound, such as a cresol novolac type epoxy compound, a phenol novolac type epoxy compound, or a biphenyl novolac type epoxy compound. In particular, it is preferable that the epoxy compound (x1) contains at least one compound selected from the group consisting of biphenyl novolac type epoxy compounds and cresol novolac type epoxy compounds. In this case, the resin contained in the carboxyl group-containing resin (A1) having the aromatic ring described above is obtained. The epoxy compound (x1) may contain only a biphenyl novolac type epoxy compound, or only a cresol novolac type epoxy compound.

[0047] The epoxy compound (x1) may contain a polymer of the ethylenically unsaturated compound (z). The ethylenically unsaturated compound (z) may contain, for example, a compound (z1) having an epoxy group such as glycidyl (meth)acrylate, or further contain a compound (z2) that does not have an epoxy group such as 2-(meth)acryloyloxyethyl phthalate. The ethylenically unsaturated compound (x2) preferably contains at least one of acrylic acid and methacrylic acid. The compound (x3) contains one or more compounds selected from the group consisting of polycarboxylic acids such as phthalic acid, tetrahydrophthalic acid, and methyltetrahydrophthalic acid, and anhydrides of these polycarboxylic acids. In particular, it is preferable that the compound (x3) contains at least one polycarboxylic acid selected from the group consisting of phthalic acid, tetrahydrophthalic acid, and methyltetrahydrophthalic acid.

[0048] The carboxyl group-containing resin (A2-2) may contain a resin (referred to as the second resin (y)) which is a reaction product of a polymer of an ethylenically unsaturated monomer containing an ethylenically unsaturated compound having a carboxyl group and an ethylenically unsaturated compound having an epoxy group. The ethylenically unsaturated monomer may further contain an ethylenically unsaturated compound that does not have a carboxyl group. The second resin (y) is obtained by reacting an ethylenically unsaturated compound having an epoxy group with some of the carboxyl groups in the polymer. The ethylenically unsaturated monomer may further contain an ethylenically unsaturated compound that does not have a carboxyl group. Examples of ethylenically unsaturated compounds containing carboxyl groups include acrylic acid, methacrylic acid, ω-carboxy-polycaprolactone (n≒2) monoacrylate, pentaerythritol triacrylate, and pentaerythritol trimethacrylate. Ethylene-unsaturated compounds that do not have a carboxyl group include, for example, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate, and (meth)acrylic acid esters of linear or branched aliphatic or alicyclic groups (which may have some unsaturated bonds in the ring). Ethylene-unsaturated compounds that have an epoxy group preferably contain glycidyl (meth)acrylate.

[0049] The carboxyl group-containing resin (A) preferably contains 25% by mass or more of the carboxyl group-containing resin (A1), more preferably 40% by mass or more, even more preferably 60% by mass or more, and particularly preferably 100% by mass. In this case, the heat resistance and insulation reliability of the cured product of the photosensitive resin composition can be particularly improved.

[0050] The carboxyl group-containing resin (A) preferably contains 25% by mass or more of carboxyl group-containing resin (A11), more preferably 40% by mass or more, even more preferably 60% by mass or more, and particularly preferably 100% by mass. In this case, excellent photosensitivity and developability with an alkaline aqueous solution can be ensured for the photosensitive resin composition. Furthermore, the heat resistance and insulation reliability of the cured product of the photosensitive resin composition can be particularly improved, and the dielectric constant can be reduced. Moreover, the tackiness of the film formed from the photosensitive resin composition can be sufficiently reduced.

[0051] The weight-average molecular weight of the carboxyl group-containing resin (A) is preferably 700 or more and 100,000 or less. When the weight-average molecular weight of the carboxyl group-containing resin (A) is 700 or more, the tackiness of the film formed from the photosensitive resin composition is easily suppressed, and the insulation reliability and plating resistance of the cured product of the photosensitive resin composition can be improved. When the weight-average molecular weight of the carboxyl group-containing resin (A) is 100,000 or less, the developability of the photosensitive resin composition with an alkaline aqueous solution tends to be good. The weight-average molecular weight of the carboxyl group-containing resin (A) is more preferably 900 or more and 60,000 or less, even more preferably 1,200 or more and 10,000 or less, and particularly preferably 1,400 or more and 5,000 or less. The weight-average molecular weight of the carboxyl group-containing resin (A) is calculated, for example, from the measurement results by gel permeation chromatography under the following conditions.

[0052] GPC equipment: SHODEX SYSTEM 11 manufactured by Showa Denko Corporation. Columns: SHODEX KF-800P, KF-005, KF-003, KF-001 (4 in series) Mobile phase: THF, Flow rate: 1ml / min, Column temperature: 45°C, Detector: RI, Conversion: Polystyrene.

[0053] The carboxyl group-containing resin (A) preferably contains a component with an acid value of 65 mg KOH / g or more and 150 mg KOH / g or less. In this case, the developability of the photosensitive resin composition with an alkaline aqueous solution is particularly easily improved. It is more preferable that the acid value is 70 mg KOH / g or more and 145 mg KOH / g or less, even more preferable that it is 75 mg KOH / g or more and 140 mg KOH / g or less, and particularly preferable that it is 85 mg KOH / g or more and 135 mg KOH / g or less.

[0054] The percentage of carboxyl group-containing resin (A) to the solid content of the photosensitive resin composition is preferably 5% by mass or more and 85% by mass or less. This percentage is more preferably 10% by mass, and even more preferably 20% by mass or more. Furthermore, this percentage is more preferably 75% by mass or less, and even more preferably 50% by mass or less.

[0055] Furthermore, the percentage of carboxyl group-containing resin (A1) relative to the solid content of the photosensitive resin composition is preferably 5% by mass or more and 85% by mass or less. This percentage is more preferably 10% by mass, and even more preferably 20% by mass or more. This percentage is also more preferably 75% by mass or less, and even more preferably 50% by mass or less.

[0056] Furthermore, the percentage of carboxyl group-containing resin (A11) relative to the solid content of the photosensitive resin composition is preferably 5% by mass or more and 85% by mass or less. This percentage is more preferably 10% by mass, and even more preferably 20% by mass or more. This percentage is also more preferably 75% by mass or less, and even more preferably 50% by mass or less.

[0057] The photopolymerization initiator (B) will be explained.

[0058] The photopolymerization initiator (B) is a component that can improve the photosensitivity of the photosensitive resin composition. Preferably, the photopolymerization initiator (B) includes at least one selected from the group consisting of, for example, α-aminoalkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, and oxime ester-based photopolymerization initiators. In this case, when the photosensitive resin composition is exposed to light such as ultraviolet light, high photosensitivity can be imparted to the photosensitive resin composition. It is even more preferable that the photopolymerization initiator (B) includes an acylphosphine oxide-based photopolymerization initiator (B1). In this case, high photosensitivity can be imparted to the photosensitive resin composition, and the insulation reliability of the cured product of the photosensitive resin composition can be particularly improved.

[0059] The α-aminoalkylphenone-based photopolymerization initiator may include, for example, at least one component selected from the group consisting of 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, and 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone.

[0060] Acylphosphine oxide-based photopolymerization initiators (B1) include, for example, monoacylphosphine oxide-based photopolymerization initiators such as 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and 2,4,6-trimethylbenzoyl-ethyl-phenyl-phosphinate, as well as bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, and bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine The product may contain at least one component selected from the group consisting of bisacyl phosphine oxide-based photopolymerization initiators such as fin oxide, bis-(2,6-dimethoxybenzoyl)phenyl phosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenyl phosphine oxide, bis-(2,4,6-trimethylbenzoyl)phenyl phosphine oxide, and (2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentyl phosphine oxide.

[0061] Oxime ester-based photopolymerization initiators may include, for example, at least one component selected from the group consisting of 1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyl oxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyl oxime).

[0062] The photosensitive resin composition may further contain appropriate photopolymerization accelerators and sensitizers. For example, the photosensitive resin composition may contain hydroxyketones such as 1-hydroxycyclohexylphenyl ketone, phenylglyoxylic acid methyl ester, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methyl-propan-1-one, and 2-hydroxy-2-methyl-1-phenyl-propan-1-one; benzoin and its alkyl ethers; acetophenones such as acetophenone and benzyldimethylketal; anthraquinones such as 2-methylanthraquinone; and 2,4-dimethyl The photosensitive resin composition may contain at least one component selected from the group consisting of thioxanthones such as luthioxanthone, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, and 2,4-diisopropylthioxanthone; benzophenones such as benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and bis(diethylamino)benzophenone; xanthones such as 2,4-diisopropylxanthone; α-hydroxyketones such as 2-hydroxy-2-methyl-1-phenyl-propan-1-one; and compounds containing a nitrogen atom such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone. The photosensitive resin composition may also contain, together with the photopolymerization initiator (B), appropriate photopolymerization accelerators and sensitizers such as tertiary amines such as p-dimethylbenzoate ethyl ester, p-dimethylaminobenzoate isoamyl ester, and 2-dimethylaminoethyl benzoate. The photosensitive resin composition may optionally contain at least one of a photopolymerization initiator for visible light exposure and a photopolymerization initiator for near-infrared exposure. The photosensitive resin composition may also contain, together with the photopolymerization initiator (B), a coumarin derivative such as 7-diethylamino-4-methylcoumarin, a carbocyanine dye system, a xanthene dye system, etc., which are sensitizers for laser exposure.

[0063] The photopolymerization initiator (B) preferably includes a hydroxyketone-based photopolymerization initiator (B2) in addition to an acylphosphine oxide-based photopolymerization initiator (B1). In other words, it is preferable that the photosensitive resin composition contains a hydroxyketone-based photopolymerization initiator (B2). In this case, the photosensitive resin composition can be given even higher photosensitivity compared to the case where the hydroxyketone-based photopolymerization initiator (B2) is not included. As a result, when a film formed from the photosensitive resin composition is cured by irradiating it with ultraviolet light, the film can be sufficiently cured from its surface to its depths. Examples of hydroxyketone-based photopolymerization initiators (B2) include 1-hydroxy-cyclohexyl-phenyl-ketone, phenylglyoxylic acid methyl ester, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, and 2-hydroxy-2-methyl-1-phenyl-propan-1-one.

[0064] The mass ratio ((B1):(B2)) of the acylphosphine oxide-based photopolymerization initiator (B1) to the hydroxyketone-based photopolymerization initiator (B2) is preferably in the range of 1:0.01 to 1:10. In this case, it is possible to improve the curability near the surface and in the deeper parts of the film formed from the photosensitive resin composition in a well-balanced manner.

[0065] The photopolymerization initiator (B) may also preferably contain bis(diethylamino)benzophenone (B3). That is, the photosensitive resin composition preferably contains an acylphosphine oxide-based photopolymerization initiator (B1) and bis(diethylamino)benzophenone (B3), or contains an acylphosphine oxide-based photopolymerization initiator (B1), a hydroxyketone-based photopolymerization initiator (B2), and bis(diethylamino)benzophenone (B3). In this case, when a coating film formed from the photosensitive resin composition is partially exposed and then developed, the curing of the unexposed parts is suppressed, resulting in particularly high resolution. This makes it possible to form very fine patterns in the cured product of the photosensitive resin composition. In particular, when an interlayer insulating layer of a multilayer printed circuit board is made from the photosensitive resin composition and small-diameter holes for through-holes are made in this interlayer insulating layer by photolithography, it becomes possible to form small-diameter holes precisely and easily.

[0066] The percentage ratio of bis(diethylamino)benzophenone (B3) to the acylphosphine oxide-based photopolymerization initiator (B1) is preferably 0.5% by mass or more and 20% by mass or less. When the bis(diethylamino)benzophenone (B3) content is 0.5% by mass or more, the resolution is particularly high. Furthermore, when the bis(diethylamino)benzophenone (B3) content is 20% by mass or less, the bis(diethylamino)benzophenone (B3) is less likely to inhibit the electrical insulation properties of the cured product of the photosensitive resin composition.

[0067] The percentage ratio of the photopolymerization initiator (B) to the carboxyl group-containing resin (A) is preferably 0.1% by mass or more and 30% by mass or less, and more preferably 1% by mass or more and 25% by mass or less.

[0068] The percentage of the photopolymerization initiator (B) relative to the total solid content of the photosensitive resin composition is preferably 0.001% by mass or more and 6% by mass or less, and more preferably 0.01% by mass or more and 3% by mass or less.

[0069] This section describes photopolymerizable compounds (C).

[0070] The photopolymerizable compound (C) can impart photosensitivity, specifically photocurability, to the photosensitive resin composition. Note that the compounds included in the carboxyl group-containing resin (A) described above are excluded from the photopolymerizable compound (C).

[0071] The photopolymerizable compound (C) includes, for example, a compound having an ethylenically unsaturated bond. More specifically, the photopolymerizable compound (C) includes at least one compound selected from the group consisting of monofunctional (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, and polyfunctional (meth)acrylates such as diethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ε-caprolactone-modified pentaerythritol hexaacrylate, and tricyclodecanedimethanol di(meth)acrylate.

[0072] The photopolymerizable compound (C) preferably contains a compound (C1) having a tricyclodecane skeleton. The compound (C1) having a tricyclodecane skeleton may include, for example, tricyclodecane dimethanol di(meth)acrylate. In this case, the dielectric loss tangent of the cured product is further reduced. The percentage ratio of the compound (C1) having a tricyclodecane skeleton to the photopolymerizable compound (C) is preferably 20% by mass or more, more preferably 40% by mass or more, and even more preferably 60% by mass or more.

[0073] The photopolymerizable compound (C) may also preferably contain a trifunctional compound, that is, a compound having three unsaturated bonds in one molecule. In this case, the developability and resolution when preparing a film from the photosensitive resin composition by photolithography are further improved. The trifunctional compound may contain at least one compound selected from the group consisting of trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethoxylated isocyanurate tri(meth)acrylate, ε-caprolactone-modified tris-(2-acryloxyethyl) isocyanurate, and ethoxylated glycerin tri(meth)acrylate.

[0074] The photopolymerizable compound (C) may also preferably contain a phosphorus-containing compound (phosphorus-containing unsaturated compound). In this case, the flame retardancy of the cured product of the photosensitive resin composition is improved. Examples of phosphorus-containing unsaturated compounds include 2-methacryloyloxyethyl acid phosphate (specifically, product numbers Light Ester P-1M and Light Ester P-2M from Kyoeisha Chemical Co., Ltd.), 2-acryloyloxyethyl acid phosphate (specifically, product number Light Acrylate P-1A from Kyoeisha Chemical Co., Ltd.), diphenyl-2-methacryloyloxyethyl phosphate (specifically, product number MR-260 from Daihachi Kogyo Co., Ltd.), and the HFA series from Showa Polymer Co., Ltd. (specifically, Diphenyl-2-methacryloyloxyethyl phosphate from Daihachi Kogyo Co., Ltd.). It may contain at least one compound selected from the group consisting of (e.g., catalog numbers HFA-6003 and HFA-6007, which are addition reaction products of pentaerythritol hexaacrylate and HCA (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), and catalog numbers HFA-3003 and HFA-6127, which are addition reaction products of caprolactone-modified dipentaerythritol hexaacrylate and HCA (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide).

[0075] The photopolymerizable compound (C) may contain a prepolymer. The prepolymer may contain at least one compound selected from the group consisting of, for example, a prepolymer obtained by polymerizing a monomer having an ethylenically unsaturated bond and then adding an ethylenically unsaturated group, and oligo(meth)acrylate prepolymers. The oligo(meth)acrylate prepolymers may contain at least one component selected from the group consisting of, for example, epoxy(meth)acrylate, polyester(meth)acrylate, urethane(meth)acrylate, alkyd resin(meth)acrylate, silicone resin(meth)acrylate, and spiran resin(meth)acrylate.

[0076] The percentage of the photopolymerizable compound (C) to the carboxyl group-containing resin (A) is preferably 1% by mass or more and 50% by mass or less. This percentage is more preferably 10% by mass or more, and even more preferably 21% by mass or more. Furthermore, this percentage is more preferably 45% by mass or less, and even more preferably 40% by mass or less.

[0077] Let's discuss epoxy compounds (D).

[0078] Since epoxy compound (D) can react with carboxyl groups in carboxyl group-containing resin (A), it can impart thermosetting properties to the photosensitive resin composition.

[0079] The epoxy compound (D) preferably contains a crystalline epoxy compound (D1). In this case, developability is more easily improved. Furthermore, if the organic filler (G) described later contains an organic filler having a carboxyl group, the carboxyl group in the organic filler makes it easier to dissolve the crystalline epoxy compound (D1) in the photosensitive resin composition. This makes it difficult for the crystalline epoxy compound (D1) to recrystallize.

[0080] The epoxy compound (D) may further contain an amorphous epoxy compound (D2). Note that a "crystalline epoxy compound" is an epoxy compound with a melting point, while an "amorphous epoxy compound" is an epoxy compound without a melting point.

[0081] The crystalline epoxy compound (D1) preferably contains one or more components selected from the group consisting of, for example, 1,3,5-tris(2,3-epoxypropyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, hydroquinone-type crystalline epoxy compounds (specifically, product name YDC-1312 manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), biphenyl-type crystalline epoxy compounds (specifically, product name YX-4000 manufactured by Mitsubishi Chemical Corporation), diphenyl ether-type crystalline epoxy compounds (specifically, product name YSLV-80DE manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), bisphenol-type crystalline epoxy compounds (specifically, product names YSLV-70XY and YSLV-80XY manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), tetrakisphenolethane-type crystalline epoxy compounds (specifically, product name GTR-1800 manufactured by Nippon Kayaku Co., Ltd.), and bisphenol fluorene-type crystalline epoxy compounds (specifically, epoxy resins having the structure shown in formula (2)).

[0082] The crystalline epoxy compound (D1) preferably has two epoxy groups in one molecule. In this case, cracks can be further reduced in the cured product when repeated temperature changes occur.

[0083] The epoxy equivalent of the crystalline epoxy compound (D1) is preferably 150 g / eq or more and 300 g / eq or less. This epoxy equivalent is the gram weight of the crystalline epoxy compound (D1) containing 1 gram equivalent of epoxy groups. The crystalline epoxy compound (D1) has a melting point. The melting point of the crystalline epoxy compound (D1) is, for example, 70°C or more and 180°C or less.

[0084] In particular, the epoxy compound (D) preferably contains a crystalline epoxy compound (D1-1) with a melting point of 110°C or lower. In this case, the developability of the photosensitive resin composition with an alkaline aqueous solution is particularly easily improved. The crystalline epoxy compound (D1-1) with a melting point of 110°C or lower may contain at least one component selected from the group consisting of, for example, biphenyl-type epoxy resin (specifically, product number YX-4000 from Mitsubishi Chemical Corporation), biphenyl ether-type epoxy resin (specifically, product number YSLV-80DE from Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), bisphenol-type epoxy resin (specifically, product numbers YSLV-70XY and YSLV-80XY from Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), and bisphenol fluorene-type crystalline epoxy compound.

[0085] Amorphous epoxy compounds (D2) include, for example, phenol novolac type epoxy resins (specifically, product code EPICLONN N-775 from DIC Corporation), cresol novolac type epoxy resins (specifically, product code EPICLONN-695 from DIC Corporation), bisphenol A novolac type epoxy resins (specifically, product code EPICLONN N-865 from DIC Corporation), bisphenol A type epoxy resins (specifically, product code jER1001 from Mitsubishi Chemical Corporation), bisphenol F type epoxy resins (specifically, product code jER4004P from Mitsubishi Chemical Corporation), bisphenol S type epoxy resins (specifically, product code EPICLONN EXA-1514 from DIC Corporation), bisphenol AD ​​type epoxy resins, biphenyl novolac type epoxy resins (specifically, product code NC-3000 from Nippon Kayaku Co., Ltd.), hydrogenated bisphenol A type epoxy resins (specifically, product code ST-4000D from Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), and naphthalene type epoxy resins (specifically, product code EPICLONN from DIC Corporation). HP-4032, EPICLON HP-4700, EPICLONHP-4770), Tertiary butylcatechol type epoxy resin (specifically, DIC Corporation's product code EPICLON HP-820), Dicyclopentadiene type epoxy resin (specifically, DIC Corporation's product code EPICLONHP-7200), Adamantane type epoxy resin (specifically, Idemitsu Kosan Co., Ltd.'s product code ADAMANTATEX-E-201), Special bifunctional epoxy resin (specifically, Mitsubishi Chemical Corporation's product codes YL7175-500 and YL7175-1000; DIC Corporation's product codes EPICLON TSR-960, EPICLON TER-601, EPICLONTSR-250-80BX, EPICLON 1650-75MPX, EPICLON EXA-4850, EPICLON EXA-4816, EPICLON EXA-4822 and EPICLONEXA-9726;It is preferable to contain at least one component selected from the group consisting of Nippon Steel & Sumitomo Metal Chemical Co., Ltd. (product code YSLV-120TE), rubbery core-shell polymer-modified bisphenol A type epoxy resin (specifically, Kaneka Corporation's product code MX-156), rubbery core-shell polymer-modified bisphenol F type epoxy resin (specifically, Kaneka Corporation's product code MX-136), and rubber particle-containing bisphenol F type epoxy resin (specifically, Kaneka Corporation's product code Kaneace MX-130).

[0086] The epoxy compound (D) may contain a phosphorus-containing epoxy resin. In this case, the flame retardancy of the cured product of the photosensitive resin composition is improved. The phosphorus-containing epoxy resin may be contained in the crystalline epoxy compound (D1) or in the amorphous epoxy compound (D2). Examples of phosphorus-containing epoxy resins include phosphorus-modified bisphenol F type epoxy resins (specific examples include product numbers EPICLON EXA-9726 and EPICLON EXA-9710 from DIC Corporation) and product number EPOTOTE FX-305 from Nippon Steel & Sumitomo Metal Chemical Co., Ltd.

[0087] Regarding the amount of epoxy compound (D) in the photosensitive resin composition, it is preferable that the equivalent amount of epoxy groups in epoxy compound (D) is 0.1 or more and less than 1 per equivalent amount of carboxyl groups in carboxyl group-containing resin (A). In this case, the dielectric loss tangent of the cured product is easily reduced while maintaining the thermosetting properties of the photosensitive resin composition. Therefore, the cured product is more likely to have even better dielectric properties. This equivalent amount of epoxy groups is more preferably 0.9 or less, and even more preferably 0.8 or less. Furthermore, this equivalent amount of epoxy groups is more preferably 0.5 or more, and even more preferably 0.7 or more.

[0088] Let's explain silica (E).

[0089] As described above, the photosensitive resin composition contains silica (E), and the percentage of silica (E) is 50% by mass or more relative to the carboxyl group-containing resin (A), which makes it easier to reduce the dielectric loss tangent of the cured product. Furthermore, silica (E) reduces the coefficient of thermal expansion of the cured product, making it less likely for warping to occur in printed circuit boards that have layers made from the cured product. In addition, the flexibility of the cured product is easily maintained when the percentage of silica (E) is 300% by mass or less. The percentage of silica (E) is more preferably 100% by mass or more, and even more preferably 130% by mass or more. Furthermore, this percentage is more preferably 250% by mass or less, and even more preferably 220% by mass or less.

[0090] The silica (E) preferably contains silica (E1) with an average particle size of 0.1 μm or more and 5 μm or less. In this case, when the surface of the cured product is treated with an oxidizing agent, fine irregularities are easily formed on the cured product, which tends to increase the surface area of ​​the cured product. Therefore, when a conductor is made by plating the surface of the cured product, the adhesion between the cured product and the conductor tends to be improved. Furthermore, the scattering of light by silica (E) is reduced, which can improve resolution. The average particle size of silica (E1) is more preferably 3 μm or less, and even more preferably 2 μm or less. In addition, this average particle size is more preferably 0.2 μm or more, and even more preferably 0.4 μm or more. The average particle size of silica (E1) is the cumulative 50% diameter (median diameter D50) calculated from the particle size distribution obtained by the laser diffraction-scattering method.

[0091] Silica (E) may contain silica (E2) having an average particle size of 1 nm to 150 nm. In this case, the cured product is less susceptible to excessive corrosion when treated with an oxidizing agent, and particularly fine irregularities are easily formed on the surface of the cured product. The average particle size of silica (E2) is more preferably 5 nm or more, even more preferably 20 nm or more, and particularly preferably 25 nm or more. Furthermore, the average particle size of silica (E2) is more preferably 120 nm or less, even more preferably 85 nm or less, and particularly preferably 65 nm or less. The average particle size of silica (E2) is the cumulative 50% diameter (median diameter D50) calculated from the particle size distribution obtained by dynamic light scattering.

[0092] Silica (E2) may contain two or more types of silica with different average particle sizes. In this case, resolution tends to be further improved, and when the surface of the cured product is treated with an oxidizing agent, fine irregularities tend to form more easily on the surface of the cured product.

[0093] Silica (E2) may include, for example, at least two types of silica (E21) and silica (E22) with different average particle sizes. The average particle size of silica (E21) with a larger average particle size is, for example, 20 nm to 100 nm, and the average particle size of silica (E22) with a smaller average particle size is, for example, 1 nm to less than 20 nm. The average particle size of silica (E21) is more preferably 20 nm or larger, and even more preferably 30 nm or larger. Furthermore, the average particle size of silica (E21) is more preferably less than 70 nm, and even more preferably 60 nm or smaller. The average particle size of silica (E22) is, for example, 1 nm to 15 nm, and even more preferably 10 nm to 15 nm, when the average particle size of silica (E21) is 20 nm to 100 nm. The mass ratio of silica (E21) to silica (E22) is preferably 20:80 to 80:20. In this case, the thermal expansion coefficient of the cured material can be further reduced, and the dielectric loss tangent can also be further reduced.

[0094] The silica (E2) preferably contains silica particles derived from silica sol. In this case, the transparency of the photosensitive resin composition may be improved. Therefore, silica (E) may contribute to improved resolution. Examples of silica sol include spherical silica sol and chain-like silica sol. Specific examples of silica sol include organo-silica sols manufactured by Nissan Chemical Industries, Ltd.: product numbers MA-ST-M, MA-ST-L, IPA-ST, IPA-ST-ZL, IPA-ST-UP, EG-ST, NPC-ST-30, PGM-ST, DMAC-ST, MEK-ST-40, MIBK-ST, MIBK-ST-L, CHO-ST-M, EAC-ST, TOL-ST, MEK-AC-4130Y, MEK-AC-5140Z, PGM-AC-2140Y, PGM-AC-4130Y, MIBK-AC-2140Z, MIKB-SD-L, MEK-EC-6150. Examples include P, MEK-EC-7150P, EP-F2130Y, EP-F6140P, EP-F7150P, PMA-ST, MEK-EC-2130Y, MEK-AC-2140Z, MEK-ST-L, MEK-ST-ZL, MEK-ST-UP; NANOCRYL from Hanse-Chemie: part numbers XP0396, XP0596, XP0733, XP0746, XP0765, XP0768, XP0953, XP0954, XP1045; NANOPOX from Hanse-Chemie: part numbers XP0516, XP0525, XP0314, etc.

[0095] Silica (E) may contain both silica (E1) and silica (E2). In this case, the mass ratio of silica (E1) to silica (E2) is, for example, 50:1 to 2:1.

[0096] The photosensitive resin composition may contain inorganic fillers other than silica (E). The inorganic filler may contain at least one selected from the group consisting of, for example, barium sulfate, carbon nanotubes, talc, bentonite, aluminum hydroxide, magnesium hydroxide, and titanium dioxide. The total percentage ratio of silica (E) to other inorganic fillers in the photosensitive resin composition is preferably 50% by mass or more and 300% by mass or less relative to the carboxyl group-containing resin (A).

[0097] It is preferable that the silica(E) is surface-treated with a silane coupling agent. In this case, the dispersibility of silica(E) in the photosensitive resin composition and in the cured product tends to be increased. In addition, silica(E) particles are more easily retained within the cured product, and when the surface of the cured product is treated with an oxidizing agent, the silica(E) particles are less likely to fall off the cured product. As a result, the surface of the cured product is less likely to be excessively corroded by the oxidizing agent.

[0098] Examples of silane coupling agents include tetraethoxysilane, tetramethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropylmethyldimethoxysilane. p-styryltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-aminoethylamino)propyltriethoxysilane, N,N-dimethyl-3-(trimethoxysilyl)propylamine, 3-triethoxysilyl-N-(1,3-Dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, allyltriethoxysilane, allyltrimethoxysilane, A Rylchlorodimethylsilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-chloropropyldimethoxymethylsilane, chloromethyltriethoxysilane, chloromethyltrimethoxysilane, 3-chloropropylmethyldiethoxysilane, 3-isocyanatetopropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, cyclohexyltrimethoxysilane, methyltriethoxysilane Lan, ethyltriethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, hexadecyltrimethoxysilane, octadecyltriethoxysilane, octadecyltrimethoxysilane, n-octyltriethoxysilane, n-octyltrimethoxysilane, dodecyltriethoxysilane, dodecyltrimethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, benzyltriethoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane It contains at least one selected from the group consisting of lan, phenyltriethoxysilane, phenyltrimethoxysilane, p-tolyltrimethoxysilane, 4-vinylphenyltrimethoxysilane, 1-naphthyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 11-pentafluorophenoxyundecyltrimethoxysilane, pentafluorophenyltrimethoxysilane, 11-azidundecyltrimethoxysilane, 2-cyanoethyltriethoxysilane, vinyltriacetoxysilane, etc.

[0099] The silane coupling agent preferably has a phenyl skeleton. In this case, the silica (E) particles are less likely to fall off. Furthermore, if the carboxyl group-containing resin (A) contains a carboxyl group-containing resin (A1) having an aromatic ring or a carboxyl group-containing resin (A11) having a bisphenol fluorene skeleton, the silica (E) particles are particularly less likely to fall off.

[0100] Only a portion of silica (E) may be surface-treated with a silane coupling agent. For example, if silica (E) contains silica (E1) and silica (E2), only silica (E1) may be surface-treated with a silane coupling agent.

[0101] Blocked isocyanate compounds (F) will be explained.

[0102] As described above, the blocked isocyanate compound (F) can lower the dielectric loss tangent of the cured product, increase its flexibility, and make the cured product less susceptible to excessive corrosion when its surface is treated with an oxidizing agent.

[0103] As described above, it is presumed that the above effect is obtained by the reaction of the blocked isocyanate compound (F) with hydroxyl groups. Examples of hydroxyl groups that can react with the blocked isocyanate compound (F) include hydroxyl groups present in the carboxyl group-containing resin (A), hydroxyl groups produced by the reaction between the carboxyl group-containing resin (A) and the epoxy compound (D), and hydroxyl groups present on the surface of silica (E). The hydroxyl groups present in the carboxyl group-containing resin (A) refer to, for example, unreacted secondary hydroxyl groups originating from the intermediate in the compound obtained by reacting a carboxylic acid or carboxylic acid anhydride with a secondary hydroxyl group in an intermediate obtained by the reaction of an epoxy compound and an unsaturated compound having a carboxyl group. The carboxyl group-containing resin (A11) and the second resin (y) described above may have such hydroxyl groups.

[0104] Furthermore, as described above, the blocked isocyanate compound (F) can improve the developability when preparing a film from a photosensitive resin composition by photolithography.

[0105] As described above, the percentage ratio of the blocked isocyanate compound (F) to the carboxyl group-containing resin (A) is 21% by mass or more and 100% by mass or less, thereby obtaining the above-mentioned effects of the blocked isocyanate compound (F). Specifically, a percentage of 21% by mass or more lowers the dielectric loss tangent of the cured product, increases the flexibility of the cured product, makes the surface of the cured product treated with an oxidizing agent less susceptible to excessive corrosion, and further improves developability. Furthermore, a percentage of 100% by mass or less also improves developability. A percentage of 24% by mass or more is more preferable, and 40% by mass or more is even more preferable. Furthermore, a percentage of 90% by mass or less is more preferable, and 80% by mass or less is even more preferable.

[0106] Further details about blocked isocyanate compound (F) will be explained. Blocked isocyanate compound (F) is a compound obtained by blocking an isocyanate compound with a blocking agent.

[0107] The number of isocyanate groups in one molecule of the isocyanate compound is, for example, 2 to 6. The isocyanate compound may be an aliphatic, alicyclic, or aromatic polyisocyanate. Examples of isocyanate compounds include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, 1,3-trimethylene diisocyanate, 1,4-tetramethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 1,9-nonameethylene diisocyanate, 1,10-decamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 2,2'-diethyl ether diisocyanate, diphenylmethane-4,4'-diisocyanate, o-xylene diisocyanate, and m-xylene diisocyanate. The product contains isocyanate compounds such as nate, p-xylene diisocyanate, methylenebis(cyclohexyl isocyanate), cyclohexane-1,3-dimethylene diisocyanate, cyclohexane-1,4-dimethylene diisocyanate, 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, 3,3'-methylenedithrylene-4,4'-diisocyanate, 4,4'-diphenyl ether diisocyanate, tetrachlorophenylene diisocyanate, norbornane diisocyanate, hydrogenated 1,3-xylylene diisocyanate, hydrogenated 1,4-xylylene diisocyanate, and at least one selected from the group consisting of these polymers. In particular, it is preferable that the isocyanate compound contains at least one compound selected from the group consisting of tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and polymers thereof. Examples of polymers include biuret derivatives, isocyanurate derivatives, and adduct derivatives, with biuret derivatives being preferred.

[0108] Examples of blocking agents in the blocked isocyanate compound (F) include oxime compounds, lactam compounds, phenol compounds, alcohol compounds, amine compounds, activated methylene compounds, pyrazole compounds, mercaptan compounds, imidazole compounds, and imide compounds. In particular, it is preferable that the blocking agent contains at least one compound selected from the group consisting of oxime compounds, lactam compounds, phenol compounds, alcohol compounds, amine compounds, activated methylene compounds, and pyrazole compounds. Examples of oxime compounds include oximes and ketoximes, specifically acetoxime, formaldehyde oxime, cyclohexane oxime, methyl ethyl ketone oxime, cyclohexanone oxime, and benzophenone oxime. Examples of lactam compounds include ε-caprolactam and γ-butyrolactam. Examples of phenol compounds include phenol, naphthol, cresol, xylenol, and halogen-substituted phenols. Examples of alcohol compounds include methanol, ethanol, propanol, butanol, cyclohexanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, and alkyl lactate. Examples of amine compounds include primary and secondary amines, such as aniline, diphenylamine, ethyleneimine, and polyethyleneimine. Examples of active methylene compounds include diethyl malonate, dimethyl malonate, ethyl acetoacetate, and methyl acetoacetate. Examples of pyrazole compounds include pyrazole, methylpyrazole, and dimethylpyrazole. Examples of mercaptan compounds include alkyl mercaptans and aryl mercaptans.

[0109] The photosensitive resin composition may further contain an organic filler (G). The organic filler (G) improves the storage stability of the photosensitive resin composition by imparting thixotropy to it. In addition, the organic filler (G) can further improve the adhesion between the cured product and the conductor.

[0110] The organic filler (G) preferably has a reactive group. In this case, the organic filler (G) has high compatibility in the photosensitive resin composition and imparts stronger thixotropy to the photosensitive resin composition, thereby further improving the storage stability of the photosensitive resin composition. In addition, the adhesion between the cured product and the conductor is further improved. The reactive group of the organic filler (G) more preferably includes at least one group selected from the group consisting of carboxyl groups, amino groups, epoxy groups, vinyl groups, and hydroxyl groups, and even more preferably includes at least one of carboxyl groups and amino groups. In this case, the storage stability of the photosensitive resin composition is further improved. In addition, the adhesion between the cured product and the conductor is further improved.

[0111] The reactive group is particularly preferably a carboxyl group. In this case, the developability of the photosensitive resin composition is improved. Furthermore, the carboxyl group of the organic filler (G) can react with the epoxy compound (D) in the photosensitive resin composition. This makes it easier for the organic filler (G) to disperse uniformly within the cured product. In addition, the carboxyl group of the organic filler (G) can improve the adhesion between the cured product and the conductor. Moreover, if the photosensitive resin composition contains a crystalline epoxy compound (D1), the compatibility of the crystalline epoxy compound (D1) in the photosensitive resin composition can be improved, making it more difficult for the crystalline epoxy compound (D1) to crystallize. Furthermore, when the photosensitive resin composition flows and a coating film is formed, the coating film is less likely to become non-uniform, making it easier to achieve uniform thickness in layers such as the solder resist layer and interlayer insulating layer made from the photosensitive resin composition.

[0112] It is also preferable that the reactive group includes a hydroxyl group. In this case, the adhesion between the cured product of the composition and the conductor is further enhanced. The reactive group may also contain both a carboxyl group and a hydroxyl group.

[0113] When the organic filler (G) has a carboxyl group, the carboxyl group is formed as a side chain in the product by polymerizing or crosslinking a carboxylic acid monomer such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, or itaconic acid. The carboxylic acid monomer has a carboxyl group and a polymerizable unsaturated double bond.

[0114] When the organic filler (G) has a carboxyl group, it is preferable that the acid value of the organic filler (G) is 1 mg KOH / g or more and 60 mg KOH / g or less. If the acid value is 1 mg KOH / g or more, the stability of the photosensitive resin composition and the developability of the cured product tend to be particularly high. If the acid value is 60 mg KOH / g or less, the moisture resistance reliability of the cured product tends to be improved. It is more preferable that the acid value of the organic filler (G) is 3 mg KOH / g or more. Furthermore, it is even more preferable that this acid value is 40 mg KOH / g or less.

[0115] The organic filler (G) preferably contains rubber particles. It is also preferable that the organic filler (G) contains only rubber particles. The rubber particles can further enhance the flexibility of the cured product. The rubber particles may have a crosslinked structure. The rubber particles include, for example, at least one polymer selected from the group consisting of crosslinked acrylic rubber, crosslinked acrylonitrile-butadiene rubber (NBR), crosslinked methyl methacrylate-butadiene-styrene (MBS), and crosslinked styrene-butadiene rubber (SBR). In this case, the flexibility of the cured product is particularly easily improved. Furthermore, the surface of the cured product is more easily and appropriately roughened when treated with an oxidizing agent.

[0116] Specific examples of rubber particles include JSR Corporation's product numbers XER-91-MEK, XER-32-MEK, and XSK-500. XER-91-MEK is a crosslinked rubber (NBR) having carboxyl groups with an average primary particle diameter of 0.07 μm, and is provided in a methyl ethyl ketone dispersion containing 15% by weight of this crosslinked rubber, with an acid value of 10.0 mgKOH / g. XER-32-MEK is a dispersion in which carboxyl group-modified hydrogenated nitrile rubber polymer (linear particles) is dispersed in methyl ethyl ketone at a content of 17% by weight relative to the total volume of the dispersion. XSK-500 is a crosslinked rubber (SBR) having carboxyl groups and hydroxyl groups with an average primary particle diameter of 0.07 μm, and is provided in a methyl ethyl ketone dispersion containing 15% by weight of this crosslinked rubber. Thus, the organic filler (G) may be incorporated into the photosensitive resin composition in the form of a dispersion. That is, rubber particles can be incorporated into the photosensitive resin composition in the form of a dispersion. In addition to the above, specific examples of the organic filler (G) include JSR Corporation's product number XER-92, etc.

[0117] The average particle size of the organic filler (G) is preferably 1 μm or less. In this case, the developability of the photosensitive resin composition tends to improve. Also, when the surface of the cured product is treated with an oxidizing agent, fine irregularities tend to form on the cured product, which tends to increase the surface area of ​​the cured product. Therefore, the adhesion between the cured product and the conductor tends to improve. The average particle size of the organic filler (G) is more preferably 0.5 μm or less, and even more preferably 0.3 μm or less. In this case, light scattering in the photosensitive resin composition can be suppressed, which tends to further improve the resolution. Also, the irregularities formed by roughening the surface of the cured product tend to become finer. Furthermore, the average particle size of the organic filler (G) is, for example, 0.001 μm or more. Note that the average particle size of the organic filler (G) is the cumulative 50% diameter (median diameter %D50) calculated from the particle size distribution measured by dynamic light scattering.

[0118] The organic filler (G) may contain particles other than rubber particles. In this case, the organic filler (G) may contain at least one particle selected from the group consisting of, for example, acrylic resin particles having carboxyl groups and cellulose particles having carboxyl groups. The acrylic resin particles having carboxyl groups may contain at least one particle component selected from the group consisting of non-crosslinked styrene-acrylic resin particles and crosslinked styrene-acrylic resin particles. A specific example of non-crosslinked styrene-acrylic resin particles is product number FS-201 (average primary particle diameter 0.5 μm) manufactured by Nippon Paint Industrial Coatings Co., Ltd. Specific examples of crosslinked styrene-acrylic resin particles are product number MG-351 (average primary particle diameter 1.0 μm) and product number BGK-001 (average primary particle diameter 1.0 μm) manufactured by Nippon Paint Industrial Coatings Co., Ltd. Furthermore, the organic filler (G) may contain particles other than those selected from the above-mentioned rubber particles, acrylic resin particles, and cellulose particles. In this case, the organic filler (G) may contain particles having carboxyl groups. In other words, the particles having this carboxyl group may be different from the particles selected from rubber particles, acrylic resin particles, and cellulose particles.

[0119] The percentage of organic filler (G) to carboxyl group-containing resin (A) is preferably 1% by mass or more and 60% by mass or less. In this case, the thixotropy of the photosensitive resin composition is particularly enhanced, and its stability is improved. In addition, the surface of the cured product is more easily roughened appropriately by the oxidizing agent, and the adhesion between the cured product and the conductor is further improved. This percentage is more preferably 3% by mass or more, and even more preferably 5% by mass or more. Furthermore, this percentage is more preferably 30% by mass or less, and even more preferably 17% by mass or less.

[0120] The photosensitive resin composition may contain a coupling agent. The coupling agent can further improve the dispersibility of silica (E), and if the photosensitive resin composition contains an organic filler (G), it can also improve the dispersibility of the organic filler (G). Furthermore, it can also improve resolution. The coupling agent has at least one atom selected from the group consisting of silicon atoms, aluminum atoms, titanium atoms, and zirconium atoms, for example. The coupling agent may also have a functional group selected from the group consisting of alkoxy groups, acyloxy groups, and alkoxides, for example. It is particularly preferable that the coupling agent has a silicon atom, that is, it is preferable that the coupling agent contains a silane coupling agent.

[0121] The percentage ratio of the coupling agent to the total of silica (E) and organic filler (G) is more preferably 0.05% by mass or more and 5% by mass or less.

[0122] The photosensitive resin composition may contain melamine. In this case, when the cured product of the photosensitive resin composition is treated with an oxidizing agent, the cured product is less likely to be excessively corroded. Melamine is 2,4,6-triamino-1,3,5-triazine, which is generally commercially available. The average particle size of melamine is preferably 20 μm or less, and more preferably 15 μm or less. When melamine is uniformly dispersed in the photosensitive resin composition, it becomes easier for the melamine to further coordinate bond with the metal element. This can further improve the adhesion of the photosensitive resin composition. The lower limit of the average particle size of melamine is not particularly limited, but it can be 0.01 μm or more. The average particle size of melamine is the cumulative 50% diameter (median diameter D50) calculated from the particle size distribution measured by laser diffraction-scattering method with melamine dispersed in the photosensitive resin composition.

[0123] When the photosensitive resin composition contains melamine, the percentage of melamine to the carboxyl group-containing resin (A) is preferably 0.1% by mass or more and 10% by mass or less. In this case, excessive corrosion when the cured product is treated with an oxidizing agent is further suppressed. This percentage is more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more, and particularly preferably 1% by mass or more. Furthermore, this percentage is more preferably 9% by mass or less, even more preferably 8% by mass or less, and particularly preferably 6% by mass or less.

[0124] The photosensitive resin composition may contain an organic solvent. The organic solvent is used for purposes such as liquefying or varnishing the photosensitive resin composition, adjusting viscosity, adjusting coatability, and adjusting film-forming properties.

[0125] The organic solvent may contain one or more compounds selected from the group consisting of, for example, linear, branched, secondary, or polyhydric alcohols such as ethanol, propyl alcohol, isopropyl alcohol, hexanol, and ethylene glycol; ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; petroleum-based aromatic mixed solvents such as the Swazole series (manufactured by Maruzen Petrochemical Co., Ltd.) and the Solvesso series (manufactured by Exxon Chemical Co., Ltd.); cellosolves such as cellosolve and butyl cellosolve; carbitols such as carbitol and butyl carbitol; propylene glycol alkyl ethers such as propylene glycol methyl ether; polypropylene glycol alkyl ethers such as dipropylene glycol methyl ether; acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, and carbitol acetate; and dialkyl glycol ethers.

[0126] When a photosensitive resin composition contains an organic solvent, it is preferable that the amount of organic solvent be adjusted so that the organic solvent evaporates quickly when the coating film formed from the photosensitive resin composition is dried, that is, so that no organic solvent remains in the dried film. In particular, it is preferable that the proportion of the organic solvent to the entire photosensitive resin composition be 0% by mass or more and 99.5% by mass or less, and more preferably 15% by mass or more and 60% by mass or less. Note that the preferred proportion of the organic solvent varies depending on the application method, so it is preferable that the proportion be appropriately adjusted according to the application method.

[0127] The photosensitive resin composition may further contain components other than those described above, as long as they do not impair the effects of this embodiment.

[0128] The photosensitive resin composition may contain at least one resin selected from the group consisting of tolylene diisocyanate, morpholine diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate blocked with caprolactam, oxime, malonic acid ester, etc.; butylated urea resin; various thermosetting resins other than those mentioned above; UV-curable epoxy (meth)acrylate; resins obtained by adding (meth)acrylic acid to epoxy resins such as bisphenol A type, phenol novolac type, cresol novolac type, and alicyclic type; and polymer compounds such as diallyl phthalate resin, phenoxy resin, urethane resin, melamine resin, and fluororesin.

[0129] The photosensitive resin composition may contain a curing agent for curing the epoxy compound (D). The curing agent may contain at least one component selected from the group consisting of, for example, imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; amine compounds such as dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, and 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipic acid hydrazide and sebacate hydrazide; phosphorus compounds such as triphenylphosphine; acid anhydrides; phenols; mercaptans; Lewis acid amine complexes; and onium salts. Commercially available products containing these components include, for example, 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, and 2P4MHZ (all trade names for imidazole compounds) from Shikoku Chemicals Co., Ltd., and U-CAT3503N, UCAT3502T (both trade names for dimethylamine blocked isocyanate compounds), DBU, DBN, U-CATSA102, and U-CAT5002 (all bicyclic amidine compounds and their salts) from Sunapro Co., Ltd.

[0130] The photosensitive resin composition may contain an adhesion promoter. Examples of adhesion promoters include guanamine derivatives such as acetoguanamine (2,4-diamino-6-methyl-1,3,5-triazine) and benzoguanamine (2,4-diamino-6-phenyl-1,3,5-triazine), as well as S-triazine derivatives such as 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-4,6-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine isocyanuric acid adduct, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine isocyanuric acid adduct, silane coupling agents, melamine derivatives, and the like.

[0131] The photosensitive resin composition may contain a rheology control agent. The rheology control agent facilitates the optimization of the viscosity of the photosensitive resin composition. Examples of rheology control agents include urea-modified medium-polarity polyamide (product numbers BYK-430 and BYK-431 from BIG Chemie Japan Co., Ltd.), polyhydroxycarboxylic acid amide (product number BYK-405 from BIG Chemie Japan Co., Ltd.), modified urea (product numbers BYK-410, BYK-411, and BYK-420 from BIG Chemie Japan Co., Ltd.), high-molecular-weight urea derivative (product number BYK-415 from BIG Chemie Japan Co., Ltd.), urea-modified urethane (product number BYK-425 from BIG Chemie Japan Co., Ltd.), polyurethane (product number BYK-428 from BIG Chemie Japan Co., Ltd.), castor oil wax, polyethylene wax, polyamide wax, bentonite, kaolin, and clay.

[0132] The photosensitive resin composition may contain at least one component selected from the group consisting of curing accelerators; colorants; copolymers such as silicones and acrylates; leveling agents; thixotropic agents; polymerization inhibitors; anti-halation agents; flame retardants; defoamers; antioxidants; surfactants; and polymer dispersants.

[0133] The photosensitive resin composition of this embodiment can be prepared by any appropriate method. For example, the photosensitive resin composition can be prepared by mixing and stirring the raw materials of the photosensitive resin composition. Alternatively, the photosensitive resin composition may be prepared by kneading using an appropriate kneading method, such as a three-roll mill, ball mill, or sand mill. If the raw materials contain liquid components, low-viscosity components, etc., the portion of the raw materials excluding the liquid components, low-viscosity components, etc., may be kneaded first to prepare a mixture, and then the liquid components, low-viscosity components, etc., may be added to the resulting mixture and mixed to prepare the photosensitive resin composition. If the photosensitive resin composition contains a solvent, some or all of the solvent may be mixed first, and then mixed with the remainder of the raw materials.

[0134] This document describes a printed circuit board containing a cured product of a photosensitive resin composition, and a method for manufacturing the same.

[0135] The printed circuit board comprises at least one of the following: an interlayer insulating layer containing a cured product of a photosensitive resin composition, and a solder resist layer containing a cured product of a photosensitive resin composition.

[0136] A printed circuit board 11 having an interlayer insulating layer 7 containing a cured product of a photosensitive resin composition will be described in detail with reference to Figures 1A to 1E.

[0137] When manufacturing a printed circuit board 11, for example, a photosensitive resin composition and a substrate 1 are prepared. The substrate 1 comprises an insulating layer 2 and a second conductor layer 3 that overlaps the insulating layer 2. An interlayer insulating layer 7 is fabricated on the substrate 1 from the photosensitive resin composition using photolithography. That is, a film 4 made from the photosensitive resin composition is placed on the substrate 1 so as to cover the second conductor layer 3, and a negative pattern-like region of the film 4, including the pattern of via holes 6, is exposed to light, and then developed using an alkaline aqueous solution. This creates an interlayer insulating layer 7 and via holes 6 that penetrate the interlayer insulating layer 7.

[0138] Specifically, for example, first, a base material 1 is prepared as shown in Figure 1A. The base material 1 comprises an insulating layer 2 and a second conductor layer 3. The second conductor layer 3 is a conductor wiring.

[0139] A photosensitive resin composition is applied to the substrate 1 and, if necessary, dried to produce a film 4 that covers the second conductive layer 3, as shown in Figure 1B. The method for applying the photosensitive resin composition is selected from the group consisting of, for example, immersion method, spray method, spin coating method, roll coating method, curtain coating method, and screen printing method. When drying the photosensitive resin composition, the photosensitive resin composition is heated to a temperature of, for example, 60°C to 130°C.

[0140] A coating 4 may be prepared by layering a dry film containing a photosensitive resin composition onto a substrate 1. The dry film is formed on a suitable support, such as one made of polyester, by applying the photosensitive resin composition to the support and then drying it. This yields a dry film with a support, comprising the dry film and a support that supports the dry film. In this dry film with a support, the dry film is layered onto the substrate 1 so as to cover the second conductive layer 3, and then pressure is applied to the dry film and the substrate 1. This results in a coating 4 made of the dry film being layered onto the substrate 1.

[0141] Next, the film 4 is exposed. For example, a negative pattern-like region of the film 4 that includes the pattern of via holes 6 is exposed. In this case, for example, ultraviolet light is irradiated onto the film 4 through a negative mask. The negative mask comprises an exposure area that transmits ultraviolet light and a non-exposure area that blocks ultraviolet light, and the pattern of the non-exposure area includes the pattern of via holes 6. The negative mask is a phototool such as a mask film or a dry plate. The ultraviolet light source is selected from the group consisting of, for example, a chemical lamp, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, a very high-pressure mercury lamp, a YAG laser, an LED, a xenon lamp, and a metal halide lamp.

[0142] When the coating 4 is made from a dry film, when exposing the coating 4, for example, the support is peeled off from the coating 4 beforehand before exposing the coating 4. Alternatively, the coating 4 may be exposed by irradiating the coating 4 with ultraviolet light while the support remains on top of the coating 4, allowing the support to pass through, and then the support may be peeled off from the exposed coating 4.

[0143] Other methods besides using a negative mask may be employed as the exposure method. For example, the film 4 may be exposed using a direct writing method in which ultraviolet light emitted from a light source is irradiated only on the portion of the film 4 to be exposed. The light source applied to the direct writing method is selected from the group consisting of, for example, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, YAG lasers, LEDs, g-line (436 nm), h-line (405 nm), i-line (365 nm), and combinations of two or more of the g-line, h-line, and i-line.

[0144] Next, the film 4 is developed with an alkaline aqueous solution to create an interlayer insulating layer 7 having via holes 6. By developing the film 4, the uncured portion 5 of the film 4 shown in Figure 1C is removed, thereby providing the via holes 6 as shown in Figure 1D. In the developing process, an appropriate developer can be used depending on the composition of the photosensitive resin composition. The developer is, for example, an alkaline aqueous solution containing at least one of alkali metal salts and alkali metal hydroxides, or an organic amine. More specifically, the alkaline aqueous solution contains at least one component selected from the group consisting of sodium carbonate, potassium carbonate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium hydroxide, potassium hydroxide, ammonium hydroxide, tetramethylammonium hydroxide, and lithium hydroxide. The solvent in the alkaline aqueous solution may be water alone, or a mixture of water and a hydrophilic organic solvent such as lower alcohols. The organic amine contains at least one component selected from the group consisting of, for example, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, and triisopropanolamine.

[0145] The alkaline aqueous solution preferably contains at least one of an alkali metal salt and / or alkali metal hydroxide, and is particularly preferably sodium carbonate. In this case, improvements to the working environment and reductions in the burden of waste disposal can be achieved.

[0146] Since the photosensitive resin composition according to this embodiment has good developability, the residue of the uncured photosensitive resin composition is less likely to remain at the bottom of the via hole 6 after development.

[0147] Next, the developed film 4 may be heat-cured by heating. The heating conditions are, for example, a heating temperature within the range of 120°C to 200°C and a heating time within the range of 20 minutes to 300 minutes. Heat-curing the film 4 in this way improves the strength, hardness, chemical resistance, and other properties of the interlayer insulating layer 7.

[0148] If necessary, the coating 4 may be further irradiated with ultraviolet light either before or after heating, or both. In this case, the photocuring of the coating 4 can be further advanced.

[0149] As a result, an interlayer insulating layer 7 made of a cured product of a photosensitive resin composition is provided on the substrate 1.

[0150] Next, the first conductor layer 8 and the via conductor 9 are fabricated, but before that, it is preferable to roughen the inner surface of the via hole 6 and the outer surface of the interlayer insulating layer 7 by treating them with an oxidizing agent. As the oxidizing agent, a desmear solution used in general desmear treatment can be used. Such an oxidizing agent contains, for example, at least one permanganate selected from the group consisting of sodium permanganate and potassium permanganate.

[0151] Next, a first conductor layer 8, which is a conductor wiring, can be fabricated on the interlayer insulating layer 7 using a known method such as the additive method, and via conductors 9 can be fabricated in the via holes 6. As a result, a printed circuit board 11 is obtained, which comprises the first conductor layer 8, the second conductor layer 3, the interlayer insulating layer 7, via holes 6, and via conductors 9, as shown in Figure 1E. In Figure 1E, the via conductors 9 are a film that covers the inside of the via holes 6, but the via conductors 9 may also fill the entire inside of the via holes 6.

[0152] In this embodiment, when the interlayer insulating layer 7 is surface-treated with an oxidizing agent, the surface of the interlayer insulating layer 7 is not excessively corroded, and fine irregularities are easily formed. Therefore, the adhesion between the interlayer insulating layer 7 and the first conductor layer 8 and via conductor 9 can be improved.

[0153] A printed circuit board having a solder resist layer containing a cured product of a photosensitive resin composition will be described in detail.

[0154] When manufacturing a printed circuit board, for example, a core material is first prepared. The core material comprises, for example, at least one insulating layer and at least one conductive wiring. A solder resist layer is fabricated on the core material from a photosensitive resin composition using photolithography. That is, a film is formed from the photosensitive resin composition on the surface of the core material on which the conductive wiring is provided. Methods for forming the film include coating and dry film methods. The same methods as those used to form the interlayer insulating layer can be used for coating and dry film methods. The film is partially cured by exposure. The exposure method can also be the same as that used to form the interlayer insulating layer. Subsequently, the film is subjected to a developing process to remove the unexposed parts of the film, thereby leaving the exposed parts of the film on the core material. Subsequently, the film on the core material is heat-cured. The developing method and heating method can also be the same as those used to form the interlayer insulating layer. If necessary, the film may be further irradiated with ultraviolet light before, after, or both of the heating process. In this case, the photocuring of the coating can be further advanced.

[0155] The thickness of the solder resist layer is not particularly limited, but may be between 3 μm and 50 μm.

[0156] As a result, a solder resist layer made of a cured photosensitive resin composition is provided on the core material. This provides a printed circuit board comprising a core material having an insulating layer and conductive wiring on it, and a solder resist layer that partially covers the surface of the core material on which the conductive wiring is provided. The surface of the solder resist layer may be roughened by surface treatment with an oxidizing agent, similar to the case of the interlayer insulating layer. This improves the adhesion between the solder resist layer and the conductors that make up the conductive wiring and solder. [Examples]

[0157] The following describes specific examples of this embodiment. However, this embodiment is not limited to the examples described below.

[0158] 1. Synthesis of carboxyl group-containing resins (1) Synthesis Example A-1: ​​Synthesis of a resin having a bisphenol fluorene skeleton In a four-necked flask equipped with a reflux condenser, thermometer, air inlet, and stirrer, 250 parts by mass of a bisphenol fluorene type epoxy compound (represented by formula (2), where R1 to R8 in formula (2) are all hydrogen, with an epoxy equivalent of 250 g / eq), 72 parts by mass of acrylic acid, 1.5 parts by mass of triphenylphosphine, 0.2 parts by mass of methyl hydroquinone, 60 parts by mass of propylene glycol monomethyl ether acetate, and 140 parts by mass of diethylene glycol monoethyl ether acetate were added. These were stirred under air bubbling to prepare a mixture. This mixture was heated in the flask under air bubbling while stirring at 115°C for 12 hours. This prepared an intermediate solution. Next, 60.8 parts by mass of 1,2,3,6-tetrahydrophthalic anhydride, 58.8 parts by mass of 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 38.7 parts by mass of propylene glycol monomethyl ether acetate were added to the intermediate solution in the flask. These were heated at 115°C for 6 hours with stirring under air bubbling, and then heated at 80°C for 1 hour with stirring under air bubbling. This yielded a solution of carboxyl group-containing resin A-1 (solid content 65% by mass). The polydispersity (Mw / Mn) of carboxyl group-containing resin A-1 was 2.15, the weight-average molecular weight (Mw) was 3096, and the acid value was 105 mgKOH / g.

[0159] (2) Synthesis example A-2: Synthesis of resin having a biphenyl novolac skeleton A mixture was prepared by adding 288 parts by mass of biphenyl novolac epoxy resin (manufactured by Nippon Kayaku Co., Ltd., product code NC-3000-H, epoxy equivalent 288 g / eq), 155 parts by mass of diethylene glycol monoethyl ether acetate, 0.2 parts by mass of methyl hydroquinone, 72 parts by mass of acrylic acid, and 3 parts by mass of triphenylphosphine to a four-necked flask equipped with a reflux condenser, thermometer, air blowing tube, and stirrer. This mixture was heated in the flask at 115°C for 12 hours while stirring under air bubbling. This prepared an intermediate solution.

[0160] Next, 91.2 parts by mass of tetrahydrophthalic anhydride and 90 parts by mass of diethylene glycol monoethyl ether acetate were added to the intermediate solution in the flask, and the mixture was heated at 90°C for 4 hours while stirring under air bubbling. This yielded a solution of carboxyl group-containing resin A-2 (solid content 65% by mass). The weight-average molecular weight of carboxyl group-containing resin A-2 was 8120, and the acid value was 76 mgKOH / g.

[0161] 2. Preparation of photosensitive resin composition A photosensitive resin composition was obtained by first kneading the powdered raw material and the carboxyl group-containing resin using a three-roller mixer, then adding the remaining raw materials and stirring and mixing them in a flask at 35°C.

[0162] In the table, "Raw Material (Solid Content) / Parts by Mass" indicates the amount of raw material used. If the raw material contains a solvent, the amount of raw material used is the amount of solid content excluding the solvent. Details of the raw materials are as follows. Furthermore, "E / A" in the table indicates the equivalent amount of epoxy groups in the epoxy compound relative to one equivalent of carboxyl groups in the carboxyl group-containing resin in the raw material. - Photopolymerization initiator A: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, manufactured by BASF, catalog number Irgacure TPO. - Photopolymerization initiator B: 1-hydroxycyclohexylphenyl ketone, manufactured by BASF, catalog number Irgacure 184. - Photopolymerization initiator C:4,4'-bis(diethylamino)benzophenone. - Photopolymerization initiator D: 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, manufactured by BASF, catalog number Irgacure 907. - Photopolymerizable compound A: Tricyclodecanedimethanol diacrylate. - Photopolymerizable compound B: Trimethylolpropane triacrylate. -Epoxy compound A: Biphenyl-type crystalline epoxy resin, product code YX-4000, manufactured by Mitsubishi Chemical Corporation, melting point 105°C, epoxy equivalent 187 g / eq. -Epoxy compound B: Bisphenol-type crystalline epoxy resin, manufactured by Nippon Steel Chemical & Material Co., Ltd., product number YSLV-80XY, melting point 75~85℃, epoxy equivalent 192g / eq. - Blocked isocyanate compound A: Product code Duranate MF-B60B, manufactured by Asahi Kasei Corporation. A hexamethylene diisocyanate type methyl ethyl ketone oxime blocked isocyanate compound, in an n-butyl n-butanol acetate solution. Solid content 60% by mass. Curing temperature 120°C or higher. -Blocked isocyanate compound B: Product code Duranate SBB-70P, manufactured by Asahi Kasei Corporation. A propylene glycol monomethyl ether acetate solution of a blocked isocyanate compound whose parent structure has a biuret structure and whose block structure has a 1,3-dimethylpyrazole skeleton. Solid content 70% by mass. Curing temperature 110°C or higher. -Blocked isocyanate compound C: Asahi Kasei Corporation, product number Duranate SBN-70D. A dipropylene glycol monomethyl ether solution of a pyrazole derivative blocked isocyanate of 1,6-hexamethylene diisocyanate. Solid content 70% by mass. Curing temperature 110°C or higher. -Blocked isocyanate compound D: Product code Duranate 17B-60P, manufactured by Asahi Kasei Corporation. A propylene glycol monomethyl ether acetate solution of a blocked isocyanate compound having a biuret structure as its parent structure and an oxime ester structure as its block structure. Solid content 60% by mass. Curing temperature 130°C or higher. - Isocyanate compound: Product code Duranate TPA-100, manufactured by Asahi Kasei Corporation. Isocyanate prepolymer having an isocyanurate structure. Solid content 100% by mass. Isocyanate group content 23% by mass. -Silica A dispersion: Product code SSP-CM1, manufactured by Admatex Co., Ltd. A slurry containing silica with an average particle size of 0.5 μm treated with phenylsilane and methyl ethyl ketone. Solid content 70% by mass. -Silica B dispersion: SC2050-MTX, manufactured by Admatex Co., Ltd. A slurry containing silica with an average particle size of 0.5 μm, treated with phenylaminosilane (KBM-573, manufactured by Shin-Etsu Chemical Co., Ltd.), and methyl ethyl ketone. Solid content 70% by mass. -Silica C dispersion: Product code SC2050-MNU, manufactured by Admatex Co., Ltd. A slurry containing silica with an average particle size of 0.5 μm treated with vinylsilane and methyl ethyl ketone. Solid content 70% by mass. -Silica D dispersion: Product code SC2050-MB, manufactured by Admatex Co., Ltd. A slurry containing silica with an average particle size of 0.5 μm treated with epoxysilane and methyl ethyl ketone. Solid content 70% by mass. -Silica E dispersion: Product code 5SQ-CM2, manufactured by Admatex Co., Ltd. A slurry containing untreated silica with an average particle size of 0.5 μm and methyl ethyl ketone. Solid content 70% by mass. -Silica sol A solvent dispersion: Part number MEK-EC-2130Y, manufactured by Nissan Chemical Corporation. A dispersion containing silica sol with an average particle size of 12 nm and methyl ethyl ketone. Solid content: 30% by mass. -Silica sol B solvent dispersion: Part number MEK-AC-4130Y, manufactured by Nissan Chemical Corporation. A dispersion containing silica sol with an average particle size of 45 nm and methyl ethyl ketone. Solid content: 30% by mass. - Dispersion of organic filler A: Product code XER-91-MEK, manufactured by JSR Corporation. A dispersion containing crosslinked rubber (NBR) with an average particle size of 0.07 μm and an acid value of 10.0 mg KOH / g, and methyl ethyl ketone. Solid content 15% by mass. - Dispersion of organic filler B: Product code OPE-2St 1200, manufactured by Mitsubishi Gas Chemical Company, Inc. A dispersion containing a vinyl benzyl-modified polyphenylene ether oligomer with a number average molecular weight of 1187 and a vinyl group equivalent of 590 g / eq, and toluene. Solid content 65% by mass. - Antioxidant: Irganox 1010, manufactured by BASF Japan Ltd. - Melamine: 2,4,6-triamino-1,3,5-triazine. Average particle size 5 μm. -Coupling agent: 3-glycidoxypropyltrimethoxysilane. - Surfactant: DIC Corporation product number Megafac F-477. - Solvent: Methyl ethyl ketone.

[0163] 3. Preparation of test pieces (1) Preparation of test pieces 1 The test pieces for conducting tests (1) to (8) in "4. Evaluation Tests" below were prepared as follows.

[0164] A photosensitive resin composition was applied to a polyethylene terephthalate film using an applicator, and then dried by heating at 90°C for 30 minutes to form a 30 μm thick dry film on the film. A glass epoxy copper-clad laminate (FR-4 type) with 17.5 μm thick copper foil was prepared. Comb-shaped electrodes with a line width / space width of 30 μm / 30 μm were formed on this glass epoxy copper-clad laminate as conductive wiring using a subtractive method to obtain a core material. The conductive wiring of this core material was roughened by dissolving and removing the surface portion of the conductive wiring, which was about 1 μm thick, with an etching agent (product code CZ-8101, manufactured by MEC Corporation). The dry film was heat-laminated onto this core material using a vacuum laminator, with the film overlapping, so as to cover the conductive wiring. The heat lamination conditions were 0.5 MPa, 80°C, and 1 minute. This formed a coating on the core material consisting of the dry film described above. Next, when exposing the film, a negative mask having unexposed areas with a pattern including circular shapes with diameters of 100 μm, 80 μm, and 60 μm was directly applied to the film overlapping the film, and 300 mJ / cm² was applied to the film. 2 Under these conditions, ultraviolet light was irradiated through the film. After exposure, the film was peeled off the dry film (coating), and then the coating was subjected to a developing process. For the developing process, a 1% Na2CO3 aqueous solution at 30°C was sprayed onto the coating at a spray pressure of 0.2 MPa for 90 seconds. Subsequently, pure water was sprayed onto the coating at a spray pressure of 0.2 MPa for 90 seconds. This removed the unexposed parts of the coating and formed via holes in the coating. Next, the coating was heated at 180°C for 120 minutes. This formed a layer on the core material consisting of a cured product of the photosensitive resin composition (which can also be called a cured product of the dry film). A test piece was then obtained.

[0165] (2) Preparation of test pieces 2 Test pieces for conducting tests (9) and (10) in "4. Evaluation Tests" below were prepared as follows.

[0166] A photosensitive resin composition was applied to a polyethylene terephthalate film using an applicator, and then dried by heating at 90°C for 30 minutes to form a 50 μm thick dry film on the film. This dry film, while still overlapping the film, was heat-laminated over one entire surface of a Teflon® film using a vacuum laminator. The heat lamination conditions were 0.5 MPa, 80°C, and 1 minute. This formed a 50 μm thick film of dry film on the Teflon film. Next, when exposing the film, a mask with a rectangular exposure area of ​​3 mm × 85 mm was directly applied to the film overlapping the film, and 300 mJ / cm² of light was applied to the film through the mask. 2 The film was irradiated with ultraviolet light under the specified conditions. After exposure, the film was peeled off the dry film (coating). Next, to develop the coating, a 1% Na2CO3 aqueous solution at 30°C was sprayed onto the coating at a spray pressure of 0.2 MPa for 90 seconds. Subsequently, the coating was washed by spraying pure water at a spray pressure of 0.2 MPa for 90 seconds. Then, the coating was heated at 180°C for 120 minutes. This formed a cured product of the photosensitive resin composition (cured dry film) on the Teflon film. This cured product was peeled off the Teflon film to obtain a test piece.

[0167] 4. Evaluation Test (1) Developability During the process of preparing test pieces, the unexposed areas of the film after development were observed, and the results were evaluated as follows. A: All unexposed areas of the coating have been removed. B: A portion of the unexposed area of ​​the film remained on the core material. After an additional 30 seconds of development (1% Na2CO3 aqueous solution, 0.2 MPa), all of the unexposed areas were removed. C: A portion of the unexposed area of ​​the film remained on the core material. Even after an additional 30 seconds of development (1% Na2CO3 aqueous solution, 0.2 MPa), a portion of the unexposed area remained on the core material. D: Could not develop.

[0168] If the evaluation was "D", the tests from (2) onward below were not conducted.

[0169] (2) Openness A commercially available swelling solution for desmearing (Swelling Dip Securigant P, manufactured by Atotec Japan Co., Ltd.) was prepared. The cured material on the test piece was immersed in this swelling solution at 60°C for 5 minutes, and then the cured material was washed with hot water. Next, a desmear solution containing potassium permanganate as an oxidizing agent (Concentrate Compact CP, manufactured by Atotec Japan Co., Ltd.) was prepared, and the cured material was immersed in the oxidizing agent at 80°C for 10 minutes to roughen the surface of the cured material. Subsequently, the cured material was washed with hot water, and then the cured material was immersed in a neutralizing solution (Reduction Solution Securigant P, manufactured by Atotec Japan Co., Ltd.) at 40°C for 5 minutes to remove any residue of the oxidizing agent from the surface of the cured material. Finally, the cured material was washed with water.

[0170] After the above treatment, the holes in the cured test pieces corresponding to the 100 μm, 80 μm, and 60 μm diameter patterns in the mask used during the curing process were observed, and the results were evaluated as follows. A: Holes corresponding to a pattern with a diameter of 100 μm, holes corresponding to a pattern with a diameter of 80 μm, and holes corresponding to a pattern with a diameter of 60 μm are all open. B: Holes corresponding to the 100 μm diameter pattern and the 80 μm diameter pattern were open, but holes corresponding to the 60 μm diameter pattern were not open. C: Holes corresponding to the 100 μm diameter pattern were open, but holes corresponding to the 80 μm diameter pattern and the 60 μm diameter pattern were not open. D: The holes corresponding to the 100 μm diameter pattern, the 80 μm diameter pattern, and the 60 μm diameter pattern were all not open.

[0171] (3) Plating resistance During the preparation of the test piece, care was taken to ensure that a portion of the conductor wiring was not covered by the layer consisting of the hardened material. On this test piece, a nickel plating layer was formed on a portion of the conductor wiring using a commercially available electroless nickel plating bath, and then a gold plating layer was formed using a commercially available electroless gold plating bath. This created a metal layer consisting of the nickel plating layer and the gold plating layer. The layer consisting of the hardened material and the metal layer were visually inspected. In addition, a cellophane adhesive tape peel test was performed on the layer consisting of the hardened material. The results were evaluated as follows. A: No abnormalities were observed in the appearance of the hardened layer or the metal layer, and no peeling of the hardened layer occurred in the cellophane adhesive tape peel test. B: Although discoloration was observed in the layer consisting of the cured material, no peeling of the layer consisting of the cured material occurred in the cellophane adhesive tape peel test. C: Significant discoloration was observed in the layer consisting of the cured material, but no peeling of the layer consisting of the cured material occurred in the cellophane adhesive tape peel test. D: Lifting of the hardened layer was observed, and peeling of the hardened layer occurred as determined by the cellophane adhesive tape peel test.

[0172] (4) Insulation A bias voltage of DC 5V was applied to the conductor wiring (comb-shaped electrodes) of the test piece, and the printed circuit board was exposed to a test environment of 130°C and 85% RH for 200 hours. The electrical resistance between the comb-shaped electrodes of the hardened material layer was continuously measured under this test environment, and the results were evaluated according to the following evaluation criteria. A: From the start of the test until 200 hours have passed, the electrical resistance value remains constant at 10 6 It maintained a value of Ω or higher. B: The electrical resistance value remains constant at 10 for the first 150 hours from the start of the test. 6 The resistance remained above Ω, but before 200 hours had passed since the start of the test, the electrical resistance value was 10 6 It became less than Ω. C: The electrical resistance value remains constant at 10 for the first 100 hours from the start of the test. 6 The resistance remained above Ω, but before 150 hours had passed since the start of the test, the electrical resistance value was 10 6It became less than Ω. D: Before 100 hours have passed from the start of the test, the electrical resistance value is 10 6 It became less than Ω.

[0173] (5) PCT (Pressure Cooker Test) After leaving the test pieces in an environment of 121°C and 100% RH for 100 hours, the appearance of the layer consisting of the cured material was evaluated according to the following criteria. A: No abnormalities were observed in the layer consisting of the hardened material. B: Slight discoloration was observed in the layer consisting of the hardened material. C: Significant discoloration was observed in the layer consisting of hardened material. D: Significant discoloration was observed in the hardened layer, and blistering had occurred in some areas.

[0174] (6) Thermal shock resistance A water-soluble flux (London Chemical, part number LONCO 3355-11) was applied to the cured layer of the test piece. The test piece was then immersed in a 280°C molten solder bath for 30 seconds, followed by immersion in 25°C water for 30 seconds. The appearance of the cured layer was then observed. This process was repeated five times, and the thermal shock resistance was evaluated as follows. A: Even after five treatments, no abnormalities such as blistering, peeling, or cracking were observed in the hardened layer. B: After 5 treatments, abnormalities such as blistering, peeling, and cracking were observed in the hardened layer, but after 4 treatments, no abnormalities such as blistering, peeling, or cracking were observed in the hardened layer. C: After four treatments, abnormalities such as blistering, peeling, and cracking were observed in the hardened layer, but after three treatments, no abnormalities such as blistering, peeling, or cracking were observed in the hardened layer. D: Within three treatments, abnormalities such as blistering, peeling, and cracking were observed in the hardened layer.

[0175] (7) Roughening resistance (evaluation of the thickness of the hardened layer after roughening) The layer made of the cured product in the test piece was treated with a swelling treatment liquid, an oxidizing agent, and a neutralizing agent in the same manner as in the method described in the above “(2) Openability” to roughen the surface of this layer.

[0176] The surface of the layer made of this cured product was observed. Subsequently, after the layer made of the cured product was ultrasonically cleaned (42 kHz, 30 seconds), it was observed again.

[0177] Based on the results, the resistance of the cured product to the oxidizing agent was evaluated according to the following evaluation criteria. A: No whitening phenomenon was observed on the surface of the layer made of the cured product, and no significant change was observed in the surface uneven shape even after ultrasonic cleaning. B: No whitening phenomenon was observed on the surface of the layer made of the cured product, but a slight desorption of silica from the surface was confirmed after ultrasonic cleaning. C: A slight whitening phenomenon was observed on the surface of the layer made of the cured product, and desorption of silica from the surface was confirmed after ultrasonic cleaning. D: The surface of the layer made of the cured product was strongly whitened, and desorption of silica from the surface was confirmed after ultrasonic cleaning.

[0178] (8) Adhesion to the copper plating layer The layer made of the cured product in the test piece was treated with a swelling treatment liquid, an oxidizing agent, and a neutralizing agent in the same manner as in the method described in the above “(2) Openability” to roughen the surface of this layer.

[0179] Subsequently, after an initial wiring was produced by electroless copper plating treatment using a commercially available chemical solution on the layer made of the cured product, the test piece was heated at 150 °C for 1 hour. Next, by electrolytic copper plating treatment under the condition of a current density of 2 A / dm 2 copper with a thickness of 33 μm was deposited on the initial wiring to produce a copper plating layer. Subsequently, the test piece was heated at 180 °C for 30 minutes.

[0180] During the process of producing the copper plating layer described above, the occurrence of blisters was checked during heating after electroless copper plating and after electrolytic copper plating. Furthermore, the adhesion strength between the copper plating layer and the cured material was measured in accordance with JIS C6481. Four measurements were performed, and the average value was calculated. The results were evaluated as follows. A: No blisters were observed during heating after electroless copper plating or after electrolytic copper plating, and the average adhesion strength was 0.40 kN / m or higher. B: No blisters were observed during heating after electroless copper plating or after electrolytic copper plating, and the average adhesion strength was 0.30 kN / m or higher and less than 0.4 kN / m. C: No blisters were observed during heating after electroless copper plating or after electrolytic copper plating, and the average adhesion strength was less than 0.3 kN / m. D: Blisters were observed during heating after electroless copper plating or after electrolytic copper plating.

[0181] (9) Relative permittivity The relative permittivity of the test pieces was measured using a dielectric constant measuring device (ADMS01O, manufactured by AET Co., Ltd.) under the cavity resonator method in accordance with JIS C2565, at a frequency of 10 GHz. The results were evaluated as follows. A: The relative permittivity is less than 3.2. B: The relative permittivity is 3.2 or higher and less than 3.5. C: The relative permittivity is 3.5 or higher and less than 3.8. D: The relative permittivity is 3.8 or higher.

[0182] (10) Dielectric loss tangent The dielectric loss tangent (tanδ) of the test piece was measured using a dielectric constant measuring device (ADMS01O, manufactured by AET Co., Ltd.) in accordance with JIS C2565, by the cavity resonator method at a frequency of 10 GHz. The results were evaluated as follows. A: The dielectric loss tangent is less than 0.008. B: The dielectric loss tangent is 0.008 or greater and less than 0.01. C: The dielectric loss tangent is 0.01 or greater and less than 0.012. D: The dielectric loss tangent is 0.012 or greater.

[0183] [Table 1]

[0184] [Table 2]

[0185] [Table 3]

Claims

1. Carboxyl group-containing resin (A), Photopolymerization initiator (B), photopolymerizable compound (C), Epoxy compound (D), Silica (E) having a percentage ratio of 50% to 300% by mass relative to the carboxyl group-containing resin (A), and surface-treated with a silane coupling agent, and The present invention contains a blocked isocyanate compound (F) in a percentage ratio of 21% by mass or more and 100% by mass or less relative to the carboxyl group-containing resin (A), The silane coupling agent has a phenyl skeleton, Photosensitive resin composition.

2. The carboxyl group-containing resin (A) contains a carboxyl group-containing resin (A1) having an aromatic ring. The photosensitive resin composition according to claim 1.

3. The carboxyl group-containing resin (A) contains a carboxyl group-containing resin (A11) having a bisphenol fluorene skeleton. The photosensitive resin composition according to claim 1 or 2.

4. The photopolymerization initiator (B) contains an acylphosphine oxide-based photopolymerization initiator (B1). A photosensitive resin composition according to any one of claims 1 to 3.

5. The equivalent amount of epoxy groups in the epoxy compound (D) is equal to the equivalent amount of the carboxyl group-containing resin (A). The amount is 0.1 or more and less than 1 per equivalent of carboxyl group. A photosensitive resin composition according to any one of claims 1 to 4.

6. The epoxy compound (D) contains a crystalline epoxy compound (D1). A photosensitive resin composition according to any one of claims 1 to 5.

7. The blocked isocyanate compound (F) is a compound obtained by blocking an isocyanate compound with a blocking agent, and the isocyanate compound contains at least one compound selected from the group consisting of tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and polymers thereof. A photosensitive resin composition according to any one of claims 1 to 6.

8. The blocking agent contains at least one compound selected from the group consisting of oxime compounds, lactam compounds, phenol compounds, alcohol compounds, amine compounds, active methylene compounds, and pyrazole compounds. The photosensitive resin composition according to claim 7.

9. The silica (E) contains silica (E1) with an average particle size of 0.1 μm or more and 5 μm or less. A photosensitive resin composition according to any one of claims 1 to 8.

10. The organic filler (G) further contains at least one particle selected from the group consisting of rubber particles, acrylic resin particles having carboxyl groups, and cellulose particles having carboxyl groups. A photosensitive resin composition according to any one of claims 1 to 9.

11. The organic filler (G) has a reactive group, The photosensitive resin composition according to claim 10.

12. A photosensitive resin composition containing the one described in any one of claims 1 to 11, Dry film.

13. A photosensitive resin composition obtained by curing the photosensitive resin composition according to any one of claims 1 to 11, cured product.

14. The interlayer insulating layer comprises the cured product described in claim 13, Printed circuit board.

15. A solder resist layer comprising the cured product described in claim 13, Printed circuit board.

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