JP7622502B2 - Photosensitive resin composition - Google Patents

Description

The present invention relates to a photosensitive resin composition. It also relates to a photosensitive film with a support, a printed wiring board, and a semiconductor device obtained using the photosensitive resin composition.

In printed wiring boards, solder resist is sometimes provided as a permanent protective film to prevent solder from adhering to areas where solder is not required and to prevent the circuit board from corroding. For the solder resist, a photosensitive resin composition such as that described in Patent Document 1 is generally used.

JP 2014-115672 A

In recent years, as printed wiring boards have become smaller and thinner, there is a demand for smaller diameter via holes.

However, the smaller the diameter of the via hole that is formed, the more likely it is that an undercut will occur. Undercut is a phenomenon in which the outline of the via does not have the intended shape at the bottom of the via, but becomes enlarged. In a via hole where an undercut has occurred, the diameter of the bottom part, which corresponds to the bottom of the via hole, is larger than the diameter of the top part, which corresponds to the opening of the via hole.

The objective of the present invention is to provide a photosensitive resin composition capable of forming small diameter via holes and producing a cured product in which the occurrence of undercuts is suppressed; and to provide a photosensitive film with a support, a printed wiring board, and a semiconductor device obtained using the photosensitive resin composition.

As a result of intensive research, the inventors discovered that by combining two or more types of resins containing ethylenically unsaturated groups and carboxyl groups with different weight average molecular weights, and further using a photopolymerization initiator with a molecular weight of 400 or more, it is possible to form small diameter via holes and obtain a cured product in which the occurrence of undercuts is suppressed, and thus completed the present invention.

（式（Ｂ－１）中、Ｒ^１は活性光線吸収基を表し、Ｒ^２はそれぞれ独立に２価の炭化水素基を表す。ｎは１～１０の整数を表す。＊は結合手を表す。）
［７］ ソルダーレジスト形成用である、［１］～［６］のいずれかに記載の感光性樹脂組成物。
［８］ 支持体と、該支持体上に設けられた、［１］～［７］のいずれかに記載の感光性樹脂組成物を含む感光性樹脂組成物層と、を有する支持体付き感光性フィルム。
［９］ ［１］～［７］のいずれかに記載の感光性樹脂組成物の硬化物により形成された絶縁層を含むプリント配線板。
［１０］ 絶縁層が、層間絶縁材、及びソルダーレジストのいずれかである、［９］に記載のプリント配線板。
［１１］ ［９］又は［１０］に記載のプリント配線板を含む、半導体装置。 That is, the present invention includes the following.
[1] (A-1) a resin containing an ethylenically unsaturated group and a carboxyl group, having a weight average molecular weight of 6,000 or less;
(A-2) a resin containing an ethylenically unsaturated group and a carboxyl group and having a weight average molecular weight 2,000 or more larger than that of the component (A-1), and (B) a photopolymerization initiator;
A photosensitive resin composition, in which the molecular weight of component (B) is 400 or more.
[2] The photosensitive resin composition according to [1], further comprising (C) an inorganic filler.
[3] The photosensitive resin composition according to [2], wherein the content of the component (C) is 1 mass% or more, based on 100 mass% of non-volatile components in the photosensitive resin composition.
[4] The photosensitive resin composition according to any one of [1] to [3], wherein the component (A-1) and the component (A-2) have any one of a cresol novolac skeleton, a bisphenol A skeleton, a bisphenol F skeleton, a biphenyl skeleton, and a naphthol aralkyl skeleton.
[5] The photosensitive resin composition according to any one of [1] to [4], wherein the component (A-1) and the component (A-2) contain an acid-modified cresol novolac skeleton-containing epoxy (meth)acrylate.
[6] The photosensitive resin composition according to any one of [1] to [5], wherein the component (B) has a structural unit represented by the following formula (B-1):

(In formula (B-1), R ¹ represents an actinic ray absorbing group, and each R ² independently represents a divalent hydrocarbon group. n represents an integer of 1 to 10. * represents a bond.)
[7] The photosensitive resin composition according to any one of [1] to [6], which is for forming a solder resist.
[8] A supported photosensitive film comprising a support and a photosensitive resin composition layer provided on the support, the photosensitive resin composition layer comprising the photosensitive resin composition according to any one of [1] to [7].
[9] A printed wiring board comprising an insulating layer formed from a cured product of the photosensitive resin composition according to any one of [1] to [7].
[10] The printed wiring board according to [9], wherein the insulating layer is either an interlayer insulating material or a solder resist.
[11] A semiconductor device comprising the printed wiring board according to [9] or [10].

The present invention provides a photosensitive resin composition capable of forming small diameter via holes and producing a cured product in which the occurrence of undercuts is suppressed; and a photosensitive film with a support, a printed wiring board, and a semiconductor device obtained using the photosensitive resin composition.

The photosensitive resin composition, the photosensitive film with a support, the printed wiring board, and the semiconductor device of the present invention are described in detail below.

[Photosensitive resin composition]
The photosensitive resin composition of the present invention comprises: (A-1) a resin containing an ethylenically unsaturated group and a carboxyl group, the resin having a weight average molecular weight of 6,000 or less; (A-2) a resin having a weight average molecular weight of 2,000 or more from the component (A-1); The composition contains a resin having a large weight average molecular weight and containing an ethylenically unsaturated group and a carboxyl group, and (B) a photopolymerization initiator, and the molecular weight of component (B) is 400 or more.

In the present invention, by using a combination of the (A-1) and (A-2) components, which have different weight average molecular weights, and the (B) component, which has a specified molecular weight, it is possible to form small diameter via holes and obtain a cured product in which the occurrence of undercuts is suppressed. In addition, in the present invention, it is usually possible to obtain a cured product that is excellent in peel strength between the conductor layer, glass transition temperature (Tg), average coefficient of linear thermal expansion (CTE), and surface shape.

The photosensitive resin composition may further contain optional components such as (C) an inorganic filler, (D) an epoxy resin, (E) a reactive diluent, (F) a solvent, and (G) other additives, as necessary. In this specification, the components (A-1) and (A-2) are sometimes collectively referred to as "(A) a resin containing an ethylenically unsaturated group and a carboxyl group." Each component contained in the photosensitive resin composition is described in detail below.

<(A) Resin containing an ethylenically unsaturated group and a carboxyl group>
The photosensitive resin composition contains (A-1) a resin containing an ethylenically unsaturated group and a carboxyl group, and having a weight average molecular weight of 6000 or less, and (A-2) a resin containing an ethylenically unsaturated group and a carboxyl group, and having a weight average molecular weight that is 2000 or more greater than that of the component (A-1). By using the components (A-1) and (A-2) in combination, it is possible to form small diameter via holes and to obtain a cured product in which the occurrence of undercuts is suppressed.

The weight average molecular weight of component (A-1) is 6000 or less, preferably 5500 or less, from the viewpoint of forming small diameter via holes and obtaining a cured product in which the occurrence of undercuts is suppressed, and the lower limit is preferably 1000 or more, more preferably 1500 or more. The weight average molecular weight of component (A-1) is the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

The weight average molecular weight of component (A-2) is at least 2000 larger than the weight average molecular weight of component (A-1), and preferably at least 2500 larger. The upper limit is preferably 20,000 or less, more preferably 17,000 or less, and even more preferably 15,000 or less. The weight average molecular weight of component (A-2) can be measured by the same method as the weight average molecular weight of component (A-1).

The specific weight average molecular weight of component (A-2) varies depending on the weight average molecular weight of component (A-1) used in combination, but is preferably 3,000 or more, more preferably 3,500 or more, and even more preferably 4,000 or more, and is preferably 20,000 or less, more preferably 17,000 or less, and even more preferably 15,000 or less.

The ethylenically unsaturated groups in the (A-1) and (A-2) components have a carbon-carbon double bond, and examples thereof include vinyl, allyl, propargyl, butenyl, ethynyl, phenylethynyl, maleimide, nadimide, and (meth)acryloyl groups. From the viewpoint of photoradical polymerization reactivity, (meth)acryloyl groups are preferred. The term "(meth)acryloyl group" includes methacryloyl, acryloyl, and combinations thereof. The (A-1) and (A-2) components contain ethylenically unsaturated groups, and therefore are capable of photoradical polymerization. The number of ethylenically unsaturated groups per molecule of the (A-1) and (A-2) components may be one or two or more. In addition, when the (A-1) and (A-2) components contain two or more ethylenically unsaturated groups per molecule, the ethylenically unsaturated groups may be the same or different.

In addition, since the components (A-1) and (A-2) contain carboxyl groups, the photosensitive resin composition containing the components (A-1) and (A-2) is soluble in an alkaline solution (for example, a 1% by mass aqueous solution of sodium carbonate as an alkaline developer). The number of carboxyl groups per molecule of the components (A-1) and (A-2) may be one or two or more.

Component (A-1) and component (A-2) are not particularly limited as long as they are compounds that have different weight average molecular weights, have ethylenically unsaturated groups and carboxyl groups, and enable photoradical polymerization and alkaline development, but a resin that has both a carboxyl group and two or more ethylenically unsaturated groups in one molecule is preferred.

One embodiment of a resin containing an ethylenically unsaturated group and a carboxyl group is an acid-modified unsaturated epoxy ester resin obtained by reacting an epoxy compound with an unsaturated carboxylic acid and then with an acid anhydride. In more detail, an unsaturated epoxy ester resin can be obtained by reacting an epoxy compound with an unsaturated carboxylic acid to obtain an unsaturated epoxy ester resin, and then reacting the unsaturated epoxy ester resin with an acid anhydride to obtain an acid-modified unsaturated epoxy ester resin.

As the epoxy compound, any compound having an epoxy group in the molecule can be used, and examples thereof include bisphenol type epoxy resins such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol F type epoxy resin, bisphenol S type epoxy resin, and modified bisphenol F type epoxy resin obtained by reacting bisphenol F type epoxy resin with epichlorohydrin to modify it to have three or more functionalities; biphenol type epoxy resins such as biphenol type epoxy resin and tetramethylbiphenol type; novolac type epoxy resins such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A type novolac type epoxy resin, and alkylphenol novolac type epoxy resin; fluorine-containing epoxy resins such as bisphenol AF type epoxy resin and perfluoroalkyl type epoxy resin; naphthalene type epoxy resin, dihydroxynaphthalene type epoxy resin, polyhydroxybinaphthalene type epoxy resin, naphthol type epoxy resin, naphthol aralkyl type epoxy resin, binaphthol type epoxy resin, Epoxy resins having a naphthalene skeleton, such as naphthylene ether type epoxy resins, naphthol novolac type epoxy resins, and naphthalene type epoxy resins obtained by the condensation reaction of polyhydroxynaphthalene with aldehydes (epoxy resins containing a naphthalene skeleton); bixylenol type epoxy resins; dicyclopentadiene type epoxy resins; trisphenol type epoxy resins; tert-butyl-catechol type epoxy resins; epoxy resins containing a condensed ring skeleton, such as anthracene type epoxy resins; glycidylamine type epoxy resins; glycidyl ester type epoxy resins; biphenyl type epoxy resins; linear aliphatic epoxy resins; epoxy resins having a butadiene structure; alicyclic epoxy resins; heterocyclic epoxy resins; spiro ring-containing epoxy resins; cyclohexane dimethanol type epoxy resins; trimethylol type epoxy resins; tetraphenylethane type epoxy resins; glycidyl group-containing acrylic resins, such as polyglycidyl (meth)acrylate and copolymers of glycidyl methacrylate and acrylic acid esters; fluorene type epoxy resins; halogenated epoxy resins, etc.

The epoxy compound is preferably an epoxy resin containing an aromatic skeleton from the viewpoint of reducing the average linear thermal expansion coefficient. Here, the aromatic skeleton is a concept that includes polycyclic aromatics and aromatic heterocycles. Among them, any of cresol novolac type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins, and naphthol aralkyl type epoxy resins is preferred, and cresol novolac type epoxy resins, biphenyl type epoxy resins, and naphthol aralkyl type epoxy resins are more preferred, and cresol novolac type epoxy resins are even more preferred, from the viewpoint of increasing the rigidity of the molecules and suppressing the movement of the molecules, thereby further reducing the average linear thermal expansion coefficient of the cured product of the resin composition.

Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, cinnamic acid, and crotonic acid, and these may be used alone or in combination of two or more. Among these, acrylic acid and methacrylic acid are preferred from the viewpoint of improving the photocurability of the photosensitive resin composition. In this specification, the epoxy ester resin, which is the reaction product of the above-mentioned epoxy compound and (meth)acrylic acid, may be referred to as "epoxy (meth)acrylate", where the epoxy group of the epoxy compound is substantially eliminated by the reaction with (meth)acrylic acid. "(meth)acrylate" refers to methacrylate and acrylate. Acrylic acid and methacrylic acid may be collectively referred to as "(meth)acrylic acid".

Examples of acid anhydrides include maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic dianhydride. Any one of these may be used alone, or two or more may be used in combination. Among these, succinic anhydride and tetrahydrophthalic anhydride are preferred from the viewpoint of improving the resolution and insulation reliability of the cured product, and tetrahydrophthalic anhydride is more preferred.

When obtaining the acid-modified unsaturated epoxy ester resin in components (A-1) and (A-2), an unsaturated carboxylic acid may be reacted with an epoxy resin in the presence of a catalyst to obtain an unsaturated epoxy ester resin, and then the unsaturated epoxy ester resin may be reacted with an acid anhydride. If necessary, a solvent or a polymerization inhibitor may be used.

The acid-modified unsaturated epoxy ester resin in the (A-1) and (A-2) components preferably has any one of a cresol novolac skeleton, a bisphenol A skeleton, a bisphenol F skeleton, a biphenyl skeleton, and a naphthol aralkyl skeleton. The acid-modified unsaturated epoxy ester resin in the (A-1) and (A-2) components is preferably an acid-modified epoxy (meth)acrylate. The "epoxy" in the acid-modified unsaturated epoxy ester resin represents the structure derived from the epoxy compound described above. For example, "acid-modified bisphenol-type epoxy (meth)acrylate" refers to an acid-modified unsaturated epoxy ester resin obtained by using a bisphenol-type epoxy resin as the epoxy compound and (meth)acrylic acid as the unsaturated carboxylic acid. The preferred range of the acid-modified epoxy (meth)acrylate is derived from the preferred range of the epoxy compound. That is, from the viewpoint of lowering the average linear thermal expansion coefficient of the cured product of the resin composition, the acid-modified unsaturated epoxy ester resin is preferably an acid-modified cresol novolac skeleton-containing epoxy (meth)acrylate, an acid-modified bisphenol A skeleton-containing epoxy (meth)acrylate, an acid-modified bisphenol F skeleton-containing epoxy (meth)acrylate, a biphenyl skeleton-containing epoxy (meth)acrylate, or a naphthol aralkyl skeleton-containing epoxy (meth)acrylate, more preferably an acid-modified cresol novolac skeleton-containing epoxy (meth)acrylate, a biphenyl skeleton-containing epoxy (meth)acrylate, or a naphthol aralkyl skeleton-containing epoxy (meth)acrylate, and even more preferably an acid-modified cresol novolac skeleton-containing epoxy (meth)acrylate. The acid-modified cresol novolac skeleton-containing epoxy (meth)acrylate is a compound obtained by reacting a reaction product of a cresol novolac type epoxy resin and a (meth)acrylate with an acid anhydride such as succinic anhydride or tetrahydrophthalic anhydride. The acid-modified bisphenol A skeleton-containing epoxy (meth)acrylate is a compound obtained by reacting a reaction product of a bisphenol A type epoxy resin and a (meth)acrylate with an acid anhydride such as succinic anhydride or tetrahydrophthalic anhydride. The acid-modified bisphenol F skeleton-containing epoxy (meth)acrylate is a compound obtained by reacting a reaction product of a bisphenol F type epoxy resin and a (meth)acrylate with an acid anhydride such as succinic anhydride or tetrahydrophthalic anhydride. The acid-modified biphenyl skeleton-containing epoxy (meth)acrylate is a compound obtained by reacting a reaction product of a biphenyl type epoxy resin and a (meth)acrylate with an acid anhydride such as succinic anhydride or tetrahydrophthalic anhydride. The acid-modified naphthol aralkyl skeleton-containing epoxy (meth)acrylate is a compound obtained by reacting a reaction product of a naphthol aralkyl type epoxy resin and a (meth)acrylate with an acid anhydride such as succinic anhydride or tetrahydrophthalic anhydride.

The acid-modified unsaturated epoxy ester resin in component (A) may be a commercially available product. Specific examples of the acid-modified unsaturated epoxy ester resin as component (A-1) include "CCR-1373H" (cresol novolac type epoxy acrylate), "ZCR-8001H" (acid-modified biphenyl type epoxy acrylate), and "ZCR-1569H" (acid-modified biphenyl type epoxy acrylate: reaction product of biphenyl type epoxy resin, acrylic acid, and acid anhydride), all manufactured by Nippon Kayaku Co., Ltd. These may be used alone or in combination of two or more.

Specific examples of the acid-modified unsaturated epoxy ester resin as component (A-2) include "CCR-1171H" (cresol novolac type epoxy acrylate) and "ZCR-1797H" (acid-modified biphenyl type epoxy acrylate) manufactured by Nippon Kayaku Co., Ltd., "ZAR-2000" (reaction product of bisphenol A type epoxy resin, acrylic acid, and succinic anhydride), "ZFR-1491H", and "ZFR-1533H" (reaction product of bisphenol F type epoxy resin, acrylic acid, and tetrahydrophthalic anhydride) manufactured by Nippon Kayaku Co., Ltd., "PR-300CP" (reaction product of cresol novolac type epoxy resin, acrylic acid, and acid anhydride) manufactured by Showa Denko KK, and "CCR-1179" (cresol novolac F type epoxy acrylate) manufactured by Nippon Kayaku Co., Ltd. These may be used alone or in combination of two or more.

As for the acid value of the (A-1) component and the (A-2) component, from the viewpoint of improving the alkaline developability of the photosensitive resin composition, the acid value is preferably 0.1 mgKOH/g or more, more preferably 0.5 mgKOH/g or more, and more preferably 1 mgKOH/g or more, 10 mgKOH/g or more, 20 mgKOH/g or more, 30 mgKOH/g or more, 40 mgKOH/g or more, and even more preferably 50 mgKOH/g or more. On the other hand, from the viewpoint of suppressing the fine pattern of the cured product from dissolving by development and improving the insulation reliability, the acid value is preferably 150 mgKOH/g or less, more preferably 120 mgKOH/g or less, and even more preferably 100 mgKOH/g or less. Here, the acid value refers to the residual acid value of the carboxyl group present in the (A) component, and the acid value can be measured by the following method. First, after precisely weighing about 1 g of the resin solution to be measured, 30 g of acetone is added to the resin solution to dissolve the resin solution uniformly. Next, an appropriate amount of phenolphthalein as an indicator is added to the solution, and titration is performed using a 0.1 N aqueous ethanol solution. The acid value is then calculated using the following formula.
Formula: A=10×(Vf-BL)×F×56.11/(Wp×I)

In the above formula, A represents the acid value (mg KOH/g), Vf represents the titer of KOH (mL), BL represents the blank, F represents the factor (titer), Wp represents the mass of the resin solution measured (g), and I represents the proportion of non-volatile matter in the resin solution measured (mass%).

In the production of components (A-1) and (A-2), from the viewpoint of improving storage stability, the ratio of the number of moles of epoxy groups in the epoxy resin to the number of moles of carboxyl groups in the total of the unsaturated carboxylic acid and acid anhydride is preferably in the range of 1:0.8 to 1.3, and more preferably in the range of 1:0.9 to 1.2.

From the viewpoint of improving alkaline developability, the total content of the (A-1) and (A-2) components is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, when the non-volatile components of the photosensitive resin composition are taken as 100% by mass. From the viewpoint of improving heat resistance, the upper limit is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less. In the present invention, the content of each component in the photosensitive resin composition is the value when the non-volatile components in the photosensitive resin composition are taken as 100% by mass, unless otherwise specified.

From the viewpoint of improving alkaline developability, the content of component (A-1) is preferably 5% by mass or more, more preferably 8% by mass or more, and even more preferably 10% by mass or more, assuming that the non-volatile components of the photosensitive resin composition are 100% by mass. From the viewpoint of improving heat resistance, the upper limit is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less.

From the viewpoint of improving alkaline developability, the content of component (A-2) is preferably 5% by mass or more, more preferably 8% by mass or more, and even more preferably 10% by mass or more, assuming that the non-volatile components of the photosensitive resin composition are 100% by mass. From the viewpoint of improving heat resistance, the upper limit is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less.

When the content of component (A-1) is a1 (mass%) and the content of component (A-2) is a2 (mass%) when the non-volatile components of the photosensitive resin composition are taken as 100 mass%, from the viewpoint of improving resolution, a1/a2 is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.3 or more, and is preferably 10 or less, more preferably 8 or less, and even more preferably 5 or less.

<(B) Photopolymerization initiator>
The photosensitive resin composition contains a photopolymerization initiator (B) as component (B). The molecular weight of component (B) is 400 or more. By containing component (B) in the photosensitive resin composition, the occurrence of undercuts is suppressed, and it is possible to obtain a cured product having excellent peel strength even if the arithmetic mean roughness (Ra) is small.

The molecular weight of component (B) is 400 or more, preferably 500 or more, more preferably 600 or more, or 700 or more, from the viewpoint of obtaining a cured product that suppresses the occurrence of undercuts and has excellent peel strength even if the arithmetic mean roughness (Ra) is small. There is no particular upper limit, but it is preferably 3000 or less, more preferably 2500 or less, and even more preferably 2000 or less.

（式（Ｂ－１）中、Ｒ^１は活性光線吸収基を表し、Ｒ^２はそれぞれ独立に２価の炭化水素基を表す。ｎは１～１０の整数を表す。＊は結合手を表す。） As the component (B), a compound having a molecular weight of 400 or more, having a group that absorbs actinic rays such as ultraviolet rays, and capable of being efficiently photocured can be used. As such a component (B), for example, a compound containing a structural unit represented by formula (B-1) can be preferably used.

(In formula (B-1), R ¹ represents an actinic ray absorbing group, and each R ² independently represents a divalent hydrocarbon group. n represents an integer of 1 to 10. * represents a bond.)

R ¹ represents an active light absorbing group. The active light absorbing group is a group that can absorb active light such as ultraviolet light. The active light absorbing group may be any functional group that can absorb active light, and examples thereof include a group having an aminoketone skeleton, a group having an anthraquinone skeleton, a group having a thioxanthone skeleton, a group having a ketal skeleton, a group having a benzophenone skeleton, a group having a xanthone skeleton, a group having an acetophenone skeleton, a group having a benzoin skeleton, a group having a thioxanthone skeleton, and a group having a benzoate skeleton.

Specific examples of the active light absorbing group include the following groups (i) to (vii). Among them, the active light absorbing group is preferably either (i) or (ii). In the formula, * represents a bond.

Each ^R2 independently represents a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include a divalent aliphatic hydrocarbon group and a divalent aromatic hydrocarbon group. From the viewpoint of obtaining the effects of the present invention remarkably, a divalent aliphatic hydrocarbon group is preferable.

As the divalent aliphatic hydrocarbon group, a divalent saturated aliphatic hydrocarbon group is preferred, and examples thereof include an alkylene group and an alkenylene group, with an alkylene group being more preferred. The alkylene group may be linear, branched, or cyclic, with a linear group being preferred. As the alkylene group, an alkylene group having 1 to 10 carbon atoms is preferred, an alkylene group having 1 to 6 carbon atoms is more preferred, and an alkylene group having 1 to 5 carbon atoms or an alkylene group having 1 to 3 carbon atoms is even more preferred. Examples of such alkylene groups include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, and a cyclohexylene group, with a methylene group being preferred. The alkenylene group may be linear, branched, or cyclic, with a linear group being preferred. As the alkenylene group, an alkenylene group having 2 to 10 carbon atoms is preferable, an alkenylene group having 2 to 6 carbon atoms is more preferable, and an alkenylene group having 2 to 5 carbon atoms is even more preferable.

Examples of divalent aromatic hydrocarbon groups include arylene groups and heteroarylene groups. As the arylene group and heteroarylene group, an arylene group or heteroarylene group having 6 to 20 carbon atoms is preferable, and an arylene group or heteroarylene group having 6 to 10 carbon atoms is more preferable.

The divalent hydrocarbon group may have a substituent. Examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, an aryl group, an arylalkyl group, a silyl group, an acyl group, an acyloxy group, a carboxy group, a sulfo group, a cyano group, a nitro group, a hydroxy group, a mercapto group, and an oxo group.

n represents an integer from 1 to 10, preferably an integer from 1 to 8, more preferably an integer from 1 to 5, and even more preferably an integer from 1 to 3.

（一般式（Ｂ－２）中、Ｒ^１１はそれぞれ独立に活性光線吸収基を表し、Ｒ^１２はそれぞれ独立に２価の炭化水素基を表し、Ｒ^１３はｍ価の炭化水素基を表す。ｎ１は１～１０の整数を表し、ｍは１～４の整数を表す。
一般式（Ｂ－３）中、Ｒ^２１、Ｒ^２３はそれぞれ独立に活性光線吸収基を表し、Ｒ^２２はそれぞれ独立に２価の炭化水素基を表す。ｎ２は１～１０の整数を表す。） The component (B) preferably contains either a compound represented by the following general formula (B-2) or a compound represented by the following general formula (B-3).

(In formula (B-2), R ¹¹ each independently represent an actinic ray absorbing group, R ¹² each independently represent a divalent hydrocarbon group, and R ¹³ represents an m-valent hydrocarbon group. n1 represents an integer of 1 to 10, and m represents an integer of 1 to 4.
In formula (B-3), R ²¹ and R ²³ each independently represent an actinic ray absorbing group, and R ²² each independently represent a divalent hydrocarbon group. n2 represents an integer of 1 to 10.

Each R ¹¹ independently represents an actinic ray absorbing group and is the same as the actinic ray absorbing group represented by R ¹ in formula (B-1).

Each R ¹² independently represents a divalent hydrocarbon group and is the same as the divalent hydrocarbon group represented by R ² in formula (B-1).

R ¹³ represents an m-valent hydrocarbon group. Examples of the m-valent hydrocarbon group include an m-valent aliphatic hydrocarbon group and an m-valent aromatic hydrocarbon group, and an m-valent aliphatic hydrocarbon group is preferred. For example, when m is 3, an alkynylene group is preferred. Specific examples of the group represented by R ¹³ include the following. In the formula, "*" represents a bond.

n1 represents an integer from 1 to 10 and is the same as n in formula (B-1).

m represents an integer from 1 to 4, preferably an integer from 1 to 3, and more preferably 3.

R ²¹ and R ²³ each independently represent an actinic ray absorbing group and are the same as the actinic ray absorbing group represented by R ¹ in formula (B-1).

Each R ²² independently represents a divalent hydrocarbon group and is the same as the divalent hydrocarbon group represented by R ² in formula (B-1).

Component (B) may be a commercially available product. Examples of commercially available products include "Omnipol 910" and "Omnipol TP" manufactured by IGM.

The content of component (B) is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, based on 100% by mass of the non-volatile components of the photosensitive resin composition, from the viewpoint of suppressing the occurrence of undercuts and obtaining a cured product with excellent peel strength even if the arithmetic mean roughness (Ra) is small. From the viewpoint of improving heat resistance, the upper limit is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

<(C) Inorganic filler>
The photosensitive resin composition may further contain an inorganic filler (C) as an optional component. By containing the component (C), it is possible to obtain a cured product having a low average linear thermal expansion coefficient. The component (C) may be used alone or in combination of two or more kinds.

(C) The material of the inorganic filler is not particularly limited, but examples thereof include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica and barium sulfate are preferred, and silica is particularly preferred. As the silica, spherical silica is preferred. (C) The inorganic filler may be used alone or in combination of two or more types.

The average particle size of the inorganic filler (C) is preferably 10 μm or less, more preferably 5 μm or less, even more preferably 3 μm or less, 2 μm or less, 1 μm or less, or 0.7 μm or less, from the viewpoint of obtaining a cured product with a low average linear thermal expansion coefficient. The lower limit of the average particle size is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.07 μm or more, 0.1 μm or more, or 0.2 μm or more.

The average particle size of the inorganic filler can be measured by a laser diffraction/scattering method based on the Mie scattering theory. Specifically, a particle size distribution of the inorganic filler is created on a volume basis using a laser diffraction/scattering particle size distribution measuring device, and the median diameter is taken as the average particle size. The measurement sample is preferably an inorganic filler dispersed in water using ultrasonic waves. Examples of laser diffraction/scattering particle size distribution measuring devices that can be used include the LA-500 manufactured by Horiba, Ltd. and the SALD-2200 manufactured by Shimadzu Corporation.

From the viewpoint of obtaining a cured product having a low average linear thermal expansion coefficient, the specific surface area of the (C) inorganic filler is preferably 1 m ² /g or more, more preferably 3 m ² /g or more, and particularly preferably 5 m ² /g or more. There is no particular upper limit, but it is preferably 60 m ² /g or less, 50 m ² /g or less, or 40 m ² /g or less. The specific surface area is obtained according to the BET method by adsorbing nitrogen gas onto the surface of a sample using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) and calculating the specific surface area using the BET multipoint method.

(C) From the viewpoint of improving moisture resistance and dispersibility, it is preferable that the inorganic filler is treated with one or more surface treatment agents such as a vinyl silane coupling agent, an amino silane coupling agent, an epoxy silane coupling agent, a mercapto silane coupling agent, a silane coupling agent, an alkoxy silane compound, an organo silazane compound, a titanate coupling agent, etc. Examples of commercially available surface treatment agents include Shin-Etsu Chemical Co., Ltd.'s "KBM-1003" (vinyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-403" (3-glycidoxypropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-803" (3-mercaptopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBE-903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd.'s "KBM-103" (phenyltrimethoxysilane), and Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy-type silane coupling agent).

(C) Commercially available inorganic fillers can be used. Examples of commercially available products include "SC2050", "SC4050", "SO-C4", "SO-C2", "SO-C1", and "Admafine" manufactured by Admatechs Co., Ltd., "SFP series" manufactured by Denki Kagaku Kogyo Co., Ltd., "SP(H) series" manufactured by Nippon Steel & Sumikin Materials Co., Ltd., "Sciqas series" manufactured by Sakai Chemical Industry Co., Ltd., "Sea Hoster series" manufactured by Nippon Shokubai Co., Ltd., "AZ series" and "AX series" manufactured by Nippon Steel & Sumikin Materials Co., Ltd., and "B series" and "BF series" manufactured by Sakai Chemical Industry Co., Ltd.

The content of (C) inorganic filler is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, 10% by mass or more, 20% by mass or more, or 30% by mass or more, based on 100% by mass of non-volatile components in the photosensitive resin composition, from the viewpoint of obtaining a cured product with a low average linear thermal expansion coefficient. The upper limit is, for example, preferably 65% by mass or less, more preferably 60% by mass or less, even more preferably 55% by mass or less, 50% by mass or less, or 40% by mass or less, based on the viewpoint of suppressing light reflection during exposure and obtaining excellent developability.

<(D) Epoxy Resin>
The photosensitive resin composition may further contain an epoxy resin (D) as an optional component. By containing the component (D), the insulation reliability of the cured product of the photosensitive resin composition can be improved. However, the component (D) does not include the epoxy resin (A) containing an ethylenically unsaturated group and a carboxyl group. The component (D) may be used alone or in combination of two or more types.

Examples of component (D) include bixylenol type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AF type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol novolac type epoxy resins, phenol novolac type epoxy resins, tert-butyl-catechol type epoxy resins, naphthalene type epoxy resins, naphthol type epoxy resins, anthracene type epoxy resins, glycidylamine type epoxy resins, glycidyl ester type epoxy resins, cresol novolac type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, naphthylene ether type epoxy resins, trimethylol type epoxy resins, tetraphenylethane type epoxy resins, tetraglycidyldiaminodiphenylmethane type epoxy resins, etc. Among these, biphenyl-type epoxy resins are preferred as component (D). The epoxy resins may be used alone or in combination of two or more.

The resin composition preferably contains, as component (D), an epoxy resin having two or more epoxy groups in one molecule. From the viewpoint of significantly obtaining the desired effects of the present invention, the ratio of the epoxy resin having two or more epoxy groups in one molecule to 100% by mass of the non-volatile components of component (D) is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more.

Epoxy resins include epoxy resins that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 20°C (hereinafter sometimes referred to as "solid epoxy resins"). The resin composition may contain only liquid epoxy resins, only solid epoxy resins, or a combination of liquid epoxy resins and solid epoxy resins as component (D), but from the viewpoint of significantly achieving the desired effects of the present invention, it is preferable to contain only solid epoxy resins.

As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups in one molecule is preferable, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is more preferable.

As solid epoxy resins, bixylenol type epoxy resins, naphthalene type epoxy resins, naphthalene type tetrafunctional epoxy resins, cresol novolac type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol type epoxy resins, biphenyl type epoxy resins, naphthylene ether type epoxy resins, anthracene type epoxy resins, bisphenol A type epoxy resins, bisphenol AF type epoxy resins, and tetraphenylethane type epoxy resins are preferred, with biphenyl type epoxy resins being more preferred.

Specific examples of solid epoxy resins include DIC's "HP4032H" (naphthalene type epoxy resin); DIC's "HP-4700" and "HP-4710" (naphthalene type tetrafunctional epoxy resin); DIC's "N-690" (cresol novolac type epoxy resin); DIC's "N-695" (cresol novolac type epoxy resin); DIC's "HP-7200", "HP-7200HH", and "HP-7200H" (dicyclopentadiene ether type epoxy resins); DIC Corporation's "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", and "HP6000" (naphthylene ether type epoxy resins); Nippon Kayaku Co., Ltd.'s "EPPN-502H" (trisphenol type epoxy resin); Nippon Kayaku Co., Ltd.'s "NC7000L" (naphthol novolac type epoxy resin); Nippon Kayaku Co., Ltd.'s "NC3000H", "NC3000", and "NC3000L" ","NC3100" (biphenyl type epoxy resin); "ESN475V" (naphthol type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN485" (naphthol novolac type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YL6121" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd.; "YX4000HK" (bixylenol type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd.; " Examples of such epoxy resins include "YX8800" (anthracene type epoxy resin); "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals; "YL7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical; "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical; "jER1010" (solid bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical; and "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical. These may be used alone or in combination of two or more types.

Preferably, the liquid epoxy resin has two or more epoxy groups in one molecule.

Preferred liquid epoxy resins are bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, glycidyl amine type epoxy resins, and epoxy resins having a butadiene structure. Preferred glycidyl amine type epoxy resins are tetraglycidyl diamino diphenyl methane type epoxy resins.

Specific examples of liquid epoxy resins include "HP4032", "HP4032D", and "HP4032SS" (naphthalene type epoxy resins) manufactured by DIC Corporation; "828US", "jER828EL", "825", and "Epicoat 828EL" (bisphenol A type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "jER807" and "1750" (bisphenol F type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "jER152" (phenol novolac type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "630" and "630LSD" (glycidylamine type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "ZX1059" (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX Corporation; and "Celloxide 2021P" (a fatty acid having an ester skeleton) manufactured by Daicel Corporation. cyclic epoxy resin); "PB-3600" manufactured by Daicel Corporation (epoxy resin having a butadiene structure); "ZX1658" and "ZX1658GS" manufactured by Nippon Steel Chemical & Material Co., Ltd. (liquid 1,4-glycidylcyclohexane type epoxy resin); "ELM-434L" manufactured by Sumitomo Chemical Co., Ltd. (glycidylamine type epoxy resin); "ELM-434VL" manufactured by Sumitomo Chemical Co., Ltd. (tetraglycidyldiaminodiphenylmethane type epoxy resin) ADEKA's "EP-3980S" (bifunctional glycidylamine type epoxy resin); ADEKA's "EP-3950L" (trifunctional glycidylamine type epoxy resin); Nissan Chemical's "TEPIC-VL" (isocyanuric ring type epoxy resin); Sumitomo Chemical's "ELM-100H" (N-[2-methyl-4-(oxiranylmethoxy)phenyl]-N-(oxiranylmethyl)oxiranemethanamine), etc. These may be used alone or in combination of two or more.

When a liquid epoxy resin and a solid epoxy resin are used in combination as component (D), the ratio by mass (liquid epoxy resin:solid epoxy resin) is preferably 1:0.01 to 1:20, more preferably 1:0.1 to 1:10, and particularly preferably 1:0.5 to 1:5. When the ratio by mass of the liquid epoxy resin and the solid epoxy resin is within this range, the desired effects of the present invention can be significantly obtained. Furthermore, when used in the form of a photosensitive film with a support, appropriate adhesion is usually obtained. Furthermore, when used in the form of a photosensitive film with a support, sufficient flexibility is obtained and handling is improved. Furthermore, a cured product having sufficient breaking strength can usually be obtained.

The epoxy equivalent of component (D) is preferably 50 g/eq. to 5000 g/eq., more preferably 50 g/eq. to 3000 g/eq., even more preferably 80 g/eq. to 2000 g/eq., and even more preferably 110 g/eq. to 1000 g/eq. Within this range, the crosslink density of the cured product of the resin composition layer is sufficient, resulting in an insulating layer with small surface roughness. The epoxy equivalent is the mass of an epoxy resin containing one equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

The weight average molecular weight (Mw) of component (D) is preferably 100 to 5000, more preferably 200 to 3000, and even more preferably 250 to 1500, from the viewpoint of significantly achieving the desired effects of the present invention. The weight average molecular weight of the resin can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC).

The content of component (D) is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, based on 100% by mass of the non-volatile components in the resin composition, from the viewpoint of obtaining an insulating layer that exhibits good mechanical strength and insulating reliability. The upper limit of the epoxy resin content is preferably 25% by mass or less, more preferably 20% by mass or less, and particularly preferably 15% by mass or less, from the viewpoint of significantly obtaining the desired effects of the present invention.

<(E) Reactive Diluent>
The photosensitive resin composition may further contain a reactive diluent (E) as an optional component. However, the components corresponding to the components (A), (B) and (D) are not included in the component (E). By including the component (E) in the photosensitive resin composition, the photoreactivity can be improved. As the component (E), for example, a photosensitive (meth)acrylate compound having one or more (meth)acryloyl groups in one molecule and being liquid, solid or semi-solid at room temperature can be used. The room temperature means about 25°C. The component (E) may be used alone or in combination of two or more types.

Representative photosensitive (meth)acrylate compounds include, for example, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxybutyl acrylate; mono- or diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; acrylamides such as N,N-dimethylacrylamide and N-methylolacrylamide; aminoalkyl acrylates such as N,N-dimethylaminoethyl acrylate; polyhydric alcohols such as trimethylolpropane, pentaerythritol, and dipentaerythritol, or polyhydric acrylates of their ethylene oxide, propylene oxide, or ε-caprolactone adducts; phenols such as phenoxy acrylate and phenoxyethyl acrylate, or acrylates such as their ethylene oxide or propylene oxide adducts; epoxy acrylates derived from glycidyl ethers such as trimethylolpropane triglycidyl ether; modified epoxy acrylates; melamine acrylates; and/or methacrylates corresponding to the above acrylates. Among these, polyvalent acrylates or polyvalent methacrylates are preferred. For example, trivalent acrylates or methacrylates include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane EO-added tri(meth)acrylate, glycerol PO-added tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, tetrafurfuryl alcohol oligo(meth)acrylate, ethyl carbitol oligo(meth)acrylate, 1,4-butanediol oligo(meth)acrylate, 1,6-hexanediol oligo(meth)acrylate, trimethylolpropane oligo(meth)acrylate, pentaerythritol oligo(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, Examples of the photosensitive (meth)acrylate compounds include hexa(meth)acrylate and (meth)acrylic acid ester of N,N,N',N'-tetrakis(β-hydroxyethyl)ethyldiamine, and examples of the trivalent or higher acrylates or methacrylates include phosphate triester (meth)acrylates such as tri(2-(meth)acryloyloxyethyl)phosphate, tri(2-(meth)acryloyloxypropyl)phosphate, tri(3-(meth)acryloyloxypropyl)phosphate, tri(3-(meth)acryloyl-2-hydroxyloxypropyl)phosphate, di(3-(meth)acryloyl-2-hydroxyloxypropyl)(2-(meth)acryloyloxyethyl)phosphate, and (3-(meth)acryloyl-2-hydroxyloxypropyl)di(2-(meth)acryloyloxyethyl)phosphate. Any one of these photosensitive (meth)acrylate compounds may be used alone, or two or more of them may be used in combination. "EO" refers to ethylene oxide.

(E) The reactive diluent may be a commercially available product. Examples of commercially available products include "DPHA" manufactured by Nippon Kayaku Co., Ltd. and "EBECRYL3708" manufactured by Daicel Allnex Co., Ltd.

The content of component (E) is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on 100% by mass of non-volatile components in the photosensitive resin composition, from the viewpoint of accelerating photocuring and suppressing stickiness when the cured product is formed, and is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less, 20% by mass or less, or 10% by mass or less.

<(F) Organic Solvent>
The photosensitive resin composition may further contain an organic solvent (F) as an optional component. The varnish viscosity can be adjusted by including the component (F). Examples of the organic solvent (F) include ketones such as methyl ethyl ketone (MEK) and cyclohexanone, aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene, glycol ethers such as methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether, esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, carbitol acetate, and ethyl diglycol acetate, aliphatic hydrocarbons such as octane and decane, and petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. These may be used alone or in combination of two or more. The content of the organic solvent when used may be appropriately adjusted from the viewpoint of the coatability of the photosensitive resin composition.

<(G) Other Additives>
The photosensitive resin composition may further contain (G) other additives to the extent that the object of the present invention is not hindered. (G) Other additives include, for example, thermoplastic resins, organic fillers, fine particles such as melamine and organic bentonite, colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, carbon black, and naphthalene black, polymerization inhibitors such as hydroquinone, phenothiazine, methylhydroquinone, hydroquinone monomethyl ether, catechol, and pyrogallol, thickeners such as bentone and montmorillonite, silicone-based, fluorine-based, and vinyl resin-based defoamers, flame retardants such as brominated epoxy compounds, acid-modified brominated epoxy compounds, antimony compounds, phosphorus-based compounds, aromatic condensed phosphate esters, and halogen-containing condensed phosphate esters, and thermosetting resins such as phenol-based curing agents and cyanate ester-based curing agents.

The photosensitive resin composition can be produced as a resin varnish by mixing the above essential components (A) and (B) with the above optional components (C) to (G) and, if necessary, kneading or stirring the mixture with a kneading means such as a triple roll mill, ball mill, bead mill, or sand mill, or a stirring means such as a super mixer, planetary mixer, or high-speed rotary mixer.

<Properties and Applications of Photosensitive Resin Composition>
The photosensitive resin composition contains the components (A-1) and (A-2), and therefore exhibits the characteristic of excellent resolution. Specifically, when the photosensitive resin composition is exposed to light and developed to form a via hole, the minimum opening diameter (minimum via diameter) of the via hole that can be formed without causing residue or peeling can be reduced. The minimum opening diameter is preferably 60 μm or less, more preferably less than 50 μm. The lower limit is not particularly limited, but may be 1 μm or more. The minimum opening diameter can be measured according to the method described in the examples below.

The photosensitive resin composition contains components (A-1) and (A-2), and therefore exhibits excellent resolution. Specifically, when a via hole is formed by exposing and developing the photosensitive resin composition, a via hole in which the occurrence of undercut is suppressed can be formed, and more specifically, a via hole in which the difference between the radius of the top and the radius of the bottom is small or no difference can be formed. Specifically, the radius (μm) of the top and the radius (μm) of the cross section of a via hole with an opening diameter of 50 μm are measured by SEM. The difference between the radius of the top and the radius of the bottom (radius of the top - radius of the bottom) is obtained. As a result, preferably less than 3 μm, more preferably no undercut (0 μm). The evaluation of the undercut can be measured according to the method described in the examples below.

After photocuring the photosensitive resin composition, the cured product is thermally cured at 180°C for 30 minutes to increase the peel strength (adhesion) between the cured product and the conductor layer formed by plating. Therefore, when an insulating layer and a solder resist are formed from this cured product, an insulating layer with high peel strength between the cured product and the plated conductor layer can be obtained. The peel strength is preferably 0.30 kgf/cm or more. The upper limit of the peel strength is not particularly limited, but may be, for example, 10.0 kgf/cm or less. The peel strength can be measured according to the method described in the examples below.

The photosensitive resin composition is photocured, and then heat cured at 180°C for 30 minutes. The roughened surface of the cured product is then roughened. The roughened surface usually exhibits low arithmetic mean roughness (Ra). Thus, the cured product provides an insulating layer with low arithmetic mean roughness. The arithmetic mean roughness is preferably 400 nm or less, more preferably 200 nm or less, and even more preferably less than 200 nm. On the other hand, the lower limit of the arithmetic mean roughness may be 1 nm or more. The arithmetic mean roughness can be evaluated according to the method described in the examples below.

After photocuring the photosensitive resin composition, the cured product is thermally cured at 170°C for 1 hour, and usually exhibits the characteristic of a high glass transition temperature (Tg). In other words, it results in an insulating layer and solder resist with a high glass transition temperature. The glass transition temperature is preferably greater than 150°C. There is no particular upper limit, but it can be 350°C or less. The glass transition temperature (Tg) can be measured according to the method described in the examples below.

After photocuring the photosensitive resin composition, the cured product is thermally cured at 170°C for 1 hour, and usually exhibits the characteristic of a low average linear thermal expansion coefficient (CTE). In other words, an insulating layer and a solder resist having a low average linear thermal expansion coefficient are obtained. The average linear thermal expansion coefficient is preferably 70 ppm or less, more preferably 50 ppm or less, and even more preferably less than 50 ppm. The lower limit is not particularly limited, but may be 10 ppm or more. The average linear thermal expansion coefficient can be measured according to the method described in the examples below.

The photosensitive resin composition of the present invention can be used in a wide range of applications requiring a photosensitive resin composition, including, but not limited to, photosensitive films with supports, insulating resin sheets such as prepregs, circuit boards (for laminates, multilayer printed wiring boards, etc.), solder resists, underfill materials, die bonding materials, semiconductor encapsulants, hole-filling resins, and component-embedding resins. In particular, the photosensitive resin composition can be suitably used as a photosensitive resin composition for insulating layers of printed wiring boards (printed wiring boards in which the cured product of the photosensitive resin composition is the insulating layer), a photosensitive resin composition for interlayer insulating layers (printed wiring boards in which the cured product of the photosensitive resin composition is the interlayer insulating layer (interlayer insulating material)), a photosensitive resin composition for plating (printed wiring boards in which plating is formed on the cured product of the photosensitive resin composition), and a photosensitive resin composition for solder resist (printed wiring boards in which the cured product of the photosensitive resin composition is the solder resist).

[Photosensitive film with support]
The photosensitive resin composition of the present invention can be suitably used in the form of a supported photosensitive film in which a photosensitive resin composition layer is formed on a support. That is, the supported photosensitive film includes a support and a photosensitive resin composition layer formed of the photosensitive resin composition of the present invention provided on the support.

Examples of the support include polyethylene terephthalate film, polyethylene naphthalate film, polypropylene film, polyethylene film, polyvinyl alcohol film, triacetyl acetate film, etc., with polyethylene terephthalate film being particularly preferred.

Examples of commercially available supports include, but are not limited to, polyethylene terephthalate films such as those manufactured by Oji Paper under the product names "Alphan MA-410" and "E-200C," polypropylene films manufactured by Shin-Etsu Film Co., Ltd., and those manufactured by Teijin under the product name "PS-25" and other PS series. These supports are preferably coated with a release agent such as a silicone coating agent on the surface in order to facilitate removal of the photosensitive resin composition layer. The thickness of the support is preferably in the range of 5 μm to 50 μm, and more preferably in the range of 10 μm to 25 μm. By making the thickness 5 μm or more, it is possible to prevent the support from breaking when peeling off the support before development, and by making the thickness 50 μm or less, it is possible to improve the resolution when exposing from above the support. In addition, supports with low fisheyes are preferred. Here, fisheyes are foreign matter, undissolved matter, oxidized deterioration products, etc. of the material that are incorporated into the film when the material is thermally melted and then kneaded, extruded, biaxially stretched, cast, etc. to produce a film.

In order to reduce light scattering during exposure to actinic rays such as ultraviolet rays, the support is preferably one with excellent transparency. Specifically, the support is preferably one with a turbidity (haze standardized by JIS-K6714), which is an index of transparency, of 0.1 to 5. Furthermore, the photosensitive resin composition layer may be protected by a protective film.

By protecting the photosensitive resin composition layer side of the photosensitive film with a support with a protective film, it is possible to prevent the adhesion of dirt and the like to the surface of the photosensitive resin composition layer and scratches. As the protective film, a film made of the same material as the support can be used. The thickness of the protective film is not particularly limited, but is preferably in the range of 1 μm to 40 μm, more preferably in the range of 5 μm to 30 μm, and even more preferably in the range of 10 μm to 30 μm. By making the thickness 1 μm or more, the handleability of the protective film can be improved, and by making the thickness 40 μm or less, the cost tends to be improved. In addition, it is preferable that the adhesive strength between the photosensitive resin composition layer and the protective film is smaller than the adhesive strength between the photosensitive resin composition layer and the support.

A photosensitive film with a support can be produced, for example, by preparing a resin varnish by dissolving the photosensitive resin composition of the present invention in an organic solvent, applying the resin varnish to a support, and drying the organic solvent by heating or blowing hot air to form a photosensitive resin composition layer. Specifically, first, bubbles in the photosensitive resin composition are completely removed by a vacuum degassing method or the like, and then the photosensitive resin composition is applied to a support, the solvent is removed by a hot air oven or far-infrared oven, the support is dried, and then a protective film is laminated on the obtained photosensitive resin composition layer as necessary to produce a photosensitive film with a support. Specific drying conditions vary depending on the curability of the photosensitive resin composition and the amount of organic solvent in the resin varnish, but in a resin varnish containing 30% to 60% by mass of organic solvent, drying can be performed at 80°C to 120°C for 3 to 13 minutes. The amount of the remaining organic solvent in the photosensitive resin composition layer is preferably 5% by mass or less, more preferably 2% by mass or less, based on the total amount of the photosensitive resin composition layer, from the viewpoint of preventing the diffusion of the organic solvent in the subsequent process. A person skilled in the art can appropriately set suitable drying conditions through simple experiments. The thickness of the photosensitive resin composition layer is preferably in the range of 5 μm to 500 μm, more preferably in the range of 10 μm to 200 μm, even more preferably in the range of 15 μm to 150 μm, even more preferably in the range of 20 μm to 100 μm, and especially preferably in the range of 20 μm to 60 μm, from the viewpoint of improving the handleability and suppressing the decrease in the sensitivity and resolution inside the photosensitive resin composition layer.

Examples of methods for applying the photosensitive resin composition include gravure coating, microgravure coating, reverse coating, kiss reverse coating, die coating, slot die, lip coating, comma coating, blade coating, roll coating, knife coating, curtain coating, chamber gravure coating, slot orifice coating, spray coating, and dip coating.

The photosensitive resin composition may be applied in several separate applications, or in one application, or a combination of different methods may be used. Among these, the die coating method is preferred, as it provides excellent uniformity of application. In addition, to avoid contamination by foreign matter, it is preferable to carry out the application process in an environment where foreign matter is unlikely to be generated, such as a clean room.

[Printed wiring board]
The printed wiring board of the present invention includes an insulating layer formed from a cured product of the photosensitive resin composition of the present invention. The insulating layer is preferably used as a solder resist.

In detail, the printed wiring board of the present invention can be manufactured using the above-mentioned photosensitive film with a support. Below, we will explain the case where the insulating layer is a solder resist.

<Lamination and drying process>
The photosensitive resin composition layer side of the supported photosensitive film is laminated onto a circuit board and dried to form a photosensitive resin composition layer on the circuit board.

Examples of circuit boards include glass epoxy boards, metal boards, polyester boards, polyimide boards, BT resin boards, and thermosetting polyphenylene ether boards. Here, the circuit board refers to a board such as the above boards on which a patterned conductor layer (circuit) is formed on one or both sides. In addition, in a multilayer printed wiring board formed by alternately laminating conductor layers and insulating layers, a board in which one or both sides of the outermost layer of the multilayer printed wiring board are patterned conductor layers (circuits) is also included in the circuit board referred to here. Note that the surface of the conductor layer may be roughened in advance by blackening, copper etching, etc.

In one embodiment of the lamination process, the photosensitive resin composition layer is laminated to one or both sides of the circuit board using a vacuum laminator. In the lamination process, if the photosensitive film with a support has a protective film, the protective film is removed, and then the photosensitive film with a support and the circuit board are preheated as necessary, and the photosensitive resin composition layer is pressed and heated while being bonded to the circuit board. For the photosensitive film with a support, a method of laminating it to the circuit board under reduced pressure by a vacuum lamination method is preferably used.

The conditions for the lamination step are not particularly limited, but for example, the lamination temperature is preferably 70°C to 140°C, the lamination pressure is preferably 1 kgf/ ^cm2 to 11 kgf/ ^cm2 (9.8 x ¹⁰⁴ N/ ^m2 to 107.9 x ¹⁰⁴ N/ ^m2 ), the lamination time is preferably 5 seconds to 300 seconds, and lamination is preferably performed under reduced pressure with an air pressure of 20 mmHg (26.7 hPa) or less. The lamination step may be a batch type or a continuous type using rolls. The vacuum lamination method can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum applicator manufactured by Nikko Materials Co., Ltd., a vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd., a roll type dry coater manufactured by Hitachi Industries Co., Ltd., and a vacuum laminator manufactured by Hitachi AIC Co., Ltd. In this manner, a photosensitive film with a support is formed on the circuit board.

Instead of laminating a photosensitive film with a support, the photosensitive resin composition may be directly applied to the circuit board in the form of a resin varnish, and the organic solvent may be dried to form a photosensitive resin composition layer on the circuit board. Screen printing is generally used as the coating method, but any other coating method that can apply the coating uniformly may be used. For example, spray coating, hot melt coating, bar coating, applicator, blade coating, knife coating, air knife coating, curtain flow coating, roll coating, gravure coating, offset printing, dip coating, brush coating, and other conventional coating methods may all be used. After coating, the coating may be dried in a hot air oven or far infrared oven as necessary. Drying conditions are preferably 80°C to 120°C for 3 to 13 minutes.

<Exposure process>
After the photosensitive resin composition layer is provided on the circuit board by the above process, an exposure process is then performed in which a predetermined portion of the photosensitive resin composition layer is irradiated with active light through a mask pattern to photocure the photosensitive resin composition layer in the irradiated portion. Examples of active light include ultraviolet light, visible light, electron beams, and X-rays, and ultraviolet light is particularly preferred. The amount of ultraviolet light is approximately 10 mJ/cm ² to 1000 mJ/cm ^2. There are two types of exposure method: a contact exposure method in which a mask pattern is closely attached to a printed wiring board, and a non-contact exposure method in which exposure is performed using parallel light without close contact, and either method may be used. In addition, when a support is present on the photosensitive resin composition layer, exposure may be performed from above the support, or exposure may be performed after peeling off the support.

The solder resist has excellent developability (resolution) because it uses the photosensitive resin composition of the present invention. For this reason, the exposure pattern in the mask pattern can be, for example, a pattern in which the ratio (L/S) of the circuit width (line; L) to the width between circuits (space; S) is 100 μm/100 μm or less (i.e., wiring pitch 200 μm or less), L/S = 80 μm/80 μm or less (wiring pitch 160 μm or less), L/S = 70 μm/70 μm or less (wiring pitch 140 μm or less), or L/S = 60 μm/60 μm or less (wiring pitch 120 μm or less). Note that the pitch does not need to be the same across the entire circuit board.

<Developing process>
After the exposure step, if a support is present on the photosensitive resin composition layer, the support is removed, and then the non-photocured portion (unexposed portion) is removed and developed by wet development or dry development, whereby a pattern can be formed.

In the case of the above-mentioned wet development, a developer that is safe, stable, and easy to operate, such as an alkaline aqueous solution, a water-based developer, or an organic solvent, is used as the developer, and among these, a development process using an alkaline aqueous solution is preferred. In addition, as the development method, a known method such as spraying, rocking immersion, brushing, or scraping is appropriately adopted.

Examples of alkaline aqueous solutions used as the developer include aqueous solutions of alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; carbonates or bicarbonates such as sodium carbonate and sodium bicarbonate; alkali metal phosphates such as sodium phosphate and potassium phosphate; and alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate; and aqueous solutions of organic bases that do not contain metal ions, such as tetraalkylammonium hydroxide. An aqueous solution of tetramethylammonium hydroxide (TMAH) is preferred because it does not contain metal ions and does not affect the semiconductor chip.

To improve the development effect, surfactants, defoamers, etc. can be added to these alkaline aqueous solutions. The pH of the alkaline aqueous solution is preferably in the range of 8 to 12, and more preferably in the range of 9 to 11. The base concentration of the alkaline aqueous solution is preferably 0.1% by mass to 10% by mass. The temperature of the alkaline aqueous solution can be appropriately selected according to the developability of the photosensitive resin composition layer, but is preferably 20°C to 50°C.

Organic solvents used as developers include, for example, acetone, ethyl acetate, alkoxyethanols having an alkoxy group with 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether.

The concentration of such an organic solvent is preferably 2% by mass to 90% by mass based on the total amount of the developer. The temperature of such an organic solvent can be adjusted according to the developability. Furthermore, such organic solvents can be used alone or in combination of two or more kinds. Examples of organic solvent-based developers used alone include 1,1,1-trichloroethane, N-methylpyrrolidone, N,N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone.

When forming a pattern, two or more of the above-mentioned development methods may be used in combination, if necessary. Development methods include the dip method, the bath method, the spray method, the high-pressure spray method, brushing, and slapping, and the high-pressure spray method is suitable for improving resolution. When using the spray method, the spray pressure is preferably 0.05 MPa to 0.3 MPa.

<Thermal curing (post-bake) process>
After the development step, a thermal curing (post-baking) step is performed to form a solder resist. Examples of the post-baking step include an ultraviolet irradiation step using a high-pressure mercury lamp and a heating step using a clean oven. When irradiating with ultraviolet light, the amount of irradiation can be adjusted as necessary, and for example, irradiation can be performed at an amount of irradiation of about 0.05 J/cm ² to 10 J/cm ^2. The heating conditions may be appropriately selected depending on the type and content of the resin component in the photosensitive resin composition, and are preferably selected in the range of 150° C. to 220° C. for 20 minutes to 180 minutes, and more preferably in the range of 160° C. to 200° C. for 30 minutes to 120 minutes.

<Other processes>
After the solder resist is formed, the printed wiring board may further include a drilling step and a desmearing step, which may be carried out according to various methods used in the manufacture of printed wiring boards and known to those skilled in the art.

After the solder resist is formed, if desired, a drilling process is performed on the solder resist formed on the circuit board to form via holes and through holes. The drilling process can be performed by known methods such as drilling, laser, plasma, etc., or by combining these methods as necessary, but a drilling process using a laser such as a carbon dioxide laser or YAG laser is preferred.

The desmear process is a process of performing a desmear treatment. Generally, resin residue (smear) adheres to the inside of the opening formed in the drilling process. Since such smears can cause poor electrical connections, a process to remove the smear (desmear treatment) is performed in this process.

The desmearing process may be performed by a dry desmearing process, a wet desmearing process, or a combination of these.

An example of a dry desmear process is a desmear process using plasma. A desmear process using plasma can be performed using a commercially available plasma desmear process. Among commercially available plasma desmear process devices, examples suitable for use in the manufacture of printed wiring boards include a microwave plasma device manufactured by Nissin Co., Ltd. and an atmospheric pressure plasma etching device manufactured by Sekisui Chemical Co., Ltd.

As the wet desmear treatment, for example, a desmear treatment using an oxidizing agent solution can be mentioned. When performing the desmear treatment using an oxidizing agent solution, it is preferable to perform the swelling treatment using a swelling liquid, the oxidation treatment using an oxidizing agent solution, and the neutralization treatment using a neutralizing liquid in this order. As the swelling liquid, for example, "Swelling Dip Securigans P" and "Swelling Dip Securigans SBU" manufactured by Atotech Japan can be mentioned. The swelling treatment is preferably performed by immersing the substrate on which the via holes and the like are formed in the swelling liquid heated to 60°C to 80°C for 5 to 10 minutes. As the oxidizing agent solution, an alkaline permanganate solution is preferable, and for example, a solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide can be mentioned. The oxidation treatment using the oxidizing agent solution is preferably performed by immersing the substrate after the swelling treatment in the oxidizing agent solution heated to 60°C to 80°C for 10 to 30 minutes. Commercially available alkaline permanganate aqueous solutions include, for example, "Concentrate Compact CP" and "Dosing Solution Securiganth P" manufactured by Atotech Japan. The neutralization treatment using a neutralizing solution is preferably carried out by immersing the substrate after the oxidation treatment in the neutralizing solution at 30°C to 50°C for 3 to 10 minutes. The neutralizing solution is preferably an acidic aqueous solution, and a commercially available product is, for example, "Reduction Solution Securiganth P" manufactured by Atotech Japan.

When dry desmear treatment and wet desmear treatment are performed in combination, the dry desmear treatment may be performed first, or the wet desmear treatment may be performed first.

When the insulating layer is used as an interlayer insulating layer, it can be carried out in the same manner as the solder resist, and after the thermal curing process, a drilling process, a desmear process, and a plating process may be carried out.

The plating process is a process for forming a conductor layer on an insulating layer. The conductor layer may be formed by combining electroless plating and electrolytic plating, or a plating resist having a reverse pattern to the conductor layer may be formed and the conductor layer may be formed only by electroless plating. Subsequent pattern formation methods may include, for example, subtractive methods and semi-additive methods known to those skilled in the art.

[Semiconductor device]
The semiconductor device of the present invention includes a printed wiring board. The semiconductor device of the present invention can be manufactured using the printed wiring board of the present invention.

Semiconductor devices include various semiconductor devices used in electrical appliances (e.g., computers, mobile phones, digital cameras, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft).

The semiconductor device of the present invention can be manufactured by mounting a component (semiconductor chip) on a conductive portion of a printed wiring board. A "conductive portion" is a portion of a printed wiring board that transmits an electrical signal, and the portion may be either on the surface or embedded. In addition, there are no particular limitations on the semiconductor chip, so long as it is an electrical circuit element made of semiconductor material.

The method of mounting the semiconductor chip when manufacturing the semiconductor device of the present invention is not particularly limited as long as the semiconductor chip functions effectively, but specific examples include a wire bonding mounting method, a flip chip mounting method, a bumpless buildup layer (BBUL) mounting method, an anisotropic conductive film (ACF) mounting method, a non-conductive film (NCF) mounting method, etc. Here, a "bumpless buildup layer (BBUL) mounting method" refers to a mounting method in which a semiconductor chip is directly embedded in a recess in a printed wiring board and the semiconductor chip is connected to the wiring on the printed wiring board.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the following description, the terms "parts" and "%" used to indicate amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. The weight average molecular weight is the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography.

<Synthesis Example 1: Synthesis of naphthol aralkyl type epoxy acrylate (1000)>
325 parts of an epoxy resin having a naphthol aralkyl skeleton with an epoxy equivalent of 325 g/eq. ("ESN-475V", manufactured by Nippon Steel Chemical & Material Co., Ltd.) was placed in a flask equipped with a gas inlet tube, a stirrer, a cooling tube and a thermometer, 340 parts of carbitol acetate was added, and the mixture was dissolved by heating, and 0.46 parts of hydroquinone and 1 part of triphenylphosphine were added. This mixture was heated to 95-105°C, and 72 parts of acrylic acid were gradually added dropwise and reacted for 16 hours. This reaction product was cooled to 80-90°C, and 80 parts of tetrahydrophthalic anhydride was added, reacted for 8 hours, and cooled. The amount of solvent was adjusted to obtain a resin solution with an acid value of 60 mgKOH/g of solid matter (non-volatile content 70%, hereinafter abbreviated as "naphthol aralkyl type epoxy acrylate (1000)"). The naphthol aralkyl type epoxy acrylate (1000) had a weight average molecular weight of 1,000.

<Examples 1 to 13 and Comparative Examples 1 to 9>
The components were mixed in the proportions shown in the table below, and a resin varnish was prepared using a high-speed rotating mixer.

Next, a PET film (Toray Industries, Inc., "Lumirror T6AM", thickness 38 μm, softening point 130°C, "release PET") that had been treated with an alkyd resin release agent (Lintec Corporation, "AL-5") was prepared as a support. The prepared resin varnish was uniformly applied to the release PET with a die coater so that the thickness of the photosensitive resin composition layer after drying was 25 μm, and the film was dried at 80°C to 110°C for 6 minutes to obtain a photosensitive film with a support having a photosensitive resin composition layer on the release PET.

<Measurement of glass transition temperature and average linear thermal expansion coefficient>
(Preparation of Cured Product A for Evaluation)
The photosensitive resin composition layer of the supported photosensitive film obtained in the Examples and Comparative Examples was irradiated with ultraviolet light at ² J/cm2 and then heat-treated at 170°C for 1 hour to obtain a cured product. The support was then peeled off to obtain a cured product A for evaluation.

(Measurement of Glass Transition Temperature (Tg))
The cured product A for evaluation was cut into a test piece having a width of about 5 mm and a length of about 15 mm, and a thermomechanical analysis was performed by a tensile load method using a dynamic viscoelasticity measuring device (EXSTAR6000, manufactured by SII Nano Technology Co., Ltd.). After mounting the test piece on the device, the measurement was performed under the measurement conditions of a load of 200 mN and a heating rate of 2°C/min. The peak top of the obtained tan δ was calculated as the glass transition temperature (°C) and evaluated according to the following criteria.
◯: Glass transition temperature is 150° C. or higher.
×: Glass transition temperature is less than 150°C.

(Measurement of average linear thermal expansion coefficient)
The cured product A for evaluation was cut into a test piece having a width of 5 mm and a length of 15 mm, and a thermomechanical analysis was performed by a tensile load method using a thermomechanical analyzer (Rigaku Thermo Plus, TMA8310). After mounting the test piece on the device, measurements were performed twice consecutively under the measurement conditions of a load of 1 g and a heating rate of 5°C/min. The average linear thermal expansion coefficient (ppm) from 25°C to 150°C in the second measurement was calculated and evaluated according to the following criteria.
◯: Average linear thermal expansion coefficient is less than 50 ppm.
Δ: The average linear thermal expansion coefficient is 50 ppm or more and 70 ppm or less.
×: The average linear thermal expansion coefficient exceeds 70 ppm.

<Preparation of Laminate A for Evaluation>
The copper layer of the glass epoxy board (copper-clad laminate) on which a circuit patterned with a copper layer having a thickness of 18 μm was formed was roughened by treatment with a surface treatment agent containing an organic acid (CZ8100, manufactured by MEC Co., Ltd.). Next, the photosensitive resin composition layer of the photosensitive film with the support obtained in the examples and comparative examples was arranged so as to be in contact with the copper circuit surface, and laminated using a vacuum laminator (manufactured by Nikko Materials Co., Ltd., VP160), and the copper-clad laminate, the photosensitive resin composition layer, and the support were laminated in this order to prepare an evaluation laminate A. The pressure bonding conditions were a vacuum drawing time of 30 seconds, a pressure bonding temperature of 80 ° C, a pressure bonding pressure of 0.7 MPa, and a pressure application time of 30 seconds. After preparing the evaluation laminate A, it was left to stand at room temperature (25 ° C) for 30 minutes or more.

<Evaluation of Resolution>
(1) Exposure, development, and curing process of photosensitive resin composition layer Using a 41-step step tablet and a round hole pattern, a pattern forming device was used to expose the support of the evaluation laminate A to ultraviolet light. The exposure pattern used a quartz glass mask that draws round holes with openings of 40 μm/50 μm/60 μm/70 μm/80 μm/90 μm/100 μm. After leaving it at room temperature for 30 minutes, the support was peeled off from the evaluation laminate A. The entire surface of the photosensitive resin composition layer on the evaluation laminate A was spray-developed with a 1% by mass aqueous sodium carbonate solution at 30 ° C. as a developer at a spray pressure of 0.2 MPa for 1 minute. After spray development, 2 J/cm ² ultraviolet light was irradiated, and the photosensitive resin composition layer was cured by further performing a heat treatment at 170 ° C. for 1 hour.

(2) Evaluation of Resolution The sensitivity of the photosensitive resin composition was determined as the amount of exposure energy at which the number of remaining gloss steps in a 41-step tablet was 8. The round holes patterned on the evaluation laminate A exposed at this sensitivity were observed with an SEM (magnification 1000x) to observe the minimum via hole diameter free of residues and peeling, and evaluated according to the following criteria.
◯: The minimum via hole diameter is less than 50 μm.
Δ: The minimum via hole diameter is 50 μm or more and 60 μm or less.
x: There is no via hole with a minimum diameter of 60 μm or less.

For undercut observation, a via hole with a diameter of 50 μm was observed with a SEM (magnification 1000 times). The radius (μm) of the top and bottom of the cross section of a via hole with an opening diameter of 50 μm was measured with a SEM, and the difference between the radius of the bottom and the radius of the top (radius of the bottom - radius of the top) was calculated. The calculated value was taken as the undercut and evaluated according to the following criteria.
◎: No undercut.
◯: Undercut is less than 3 μm.
△: Undercut is 3 μm or more and 6 μm or less.
×: Undercut is more than 6 μm, or a via hole with a diameter of 50 μm is not opened.

<Evaluation of roughness and peel strength>
(1) Exposure, development, and curing process of photosensitive resin composition layer Using a pattern forming device, ultraviolet exposure was performed from the support of the evaluation laminate A at an exposure energy such that the number of gloss remaining steps of the 41-step step tablet was 8 steps. A quartz glass mask without an exposure pattern was used. After leaving it at room temperature for 30 minutes, the support was peeled off from the evaluation laminate A. A 1% by mass aqueous sodium carbonate solution at 30 ° C. as a developer was spray-developed on the entire surface of the photosensitive resin composition layer on the evaluation laminate A at a spray pressure of 0.2 MPa for 1 minute. After spray development, ultraviolet irradiation of 2 J / cm ² was performed, and further heat treatment at 170 ° C. for 1 hour was performed to cure the photosensitive resin composition layer.

(2) Roughening Treatment The evaluation laminate A was immersed in a swelling liquid, Swelling Dip Securigand P containing diethylene glycol monobutyl ether, manufactured by Atotech Japan, for 10 minutes at 60° C., then in a roughening liquid, Concentrate Compact P (aqueous solution of _KMnO4 : 60 g/L, NaOH: 40 g/L) manufactured by Atotech Japan, for 10 minutes at 80° C., and finally in a neutralizing liquid, Reduction Showreusin Securigant P, manufactured by Atotech Japan, for 5 minutes at 40° C. The evaluation laminate A after this roughening treatment was designated as Sample A.

(3) Plating by semi-additive process In order to form a circuit on the insulating layer surface, sample A was immersed in an electroless plating solution containing _PdCl2 , and then immersed in an electroless copper plating solution. After heating at 150°C for 30 minutes to perform annealing, an etching resist was formed, and after pattern formation by etching, copper sulfate electroplating was performed to form a conductor layer with a thickness of 25 μm. Next, annealing was performed at 180°C for 60 minutes. This sample A was designated as sample B.

(4) Measurement of arithmetic mean roughness (Ra) For sample A, the arithmetic mean roughness (Ra) was determined using a non-contact surface roughness meter (WYKO NT3300 manufactured by Veeco Instruments) in VSI mode with a 50x lens over a measurement range of 121 μm×92 μm. The average of 10 points was calculated as the measured value, and the results were evaluated according to the following criteria.
◯: The arithmetic mean roughness is less than 200 μm.
Δ: The arithmetic mean roughness is 200 μm or more and 400 μm or less.
×: The arithmetic mean roughness is greater than 400 μm.

(5) Measurement of peel strength of plated conductor layer A cut was made in the conductor layer of Sample B, measuring 10 mm in width and 100 mm in length, and one end of the cut was peeled off and held with a gripper (Autocom type testing machine, AC-50C-SL, manufactured by TSE Corporation). The load (kgf/cm) when 35 mm was peeled off in the vertical direction at a speed of 50 mm/min at room temperature was measured and evaluated according to the following criteria.
A: Peel strength is 0.3 kgf/cm or more.
×: Peel strength is less than 0.3 kgf/cm.

・ＯｍｎｉｐｏｌＴＰ：下記構造で表される化合物（ＩＧＭ社製、分子量は９００以上）式中、ａ、ｂ、ｃはそれぞれ１～１０の整数を表す。

・Ｏｍｎｉｒａｄ３７９ＥＧ：（ＩＧＭ社製、分子量３８０．５）

・ＯｍｎｉｒａｄＴＰＯ：（ＩＧＭ社製、分子量３４８）

・ＮＣ３０００Ｈ：ビフェニル型エポキシ樹脂（日本化薬社製、エポキシ当量２７１ｇ／ｅｑ．）
・ＳＯ－Ｃ２：無機充填材（球状シリカ、アドマテックス社製、平均粒径０．５μｍ、比表面積６ｍ^２／ｇ）
・ＤＰＨＡ：ジペンタエリスリトールヘキサアクリレート（日本化薬社製）
・ＥＤＧ－Ａｃ：エチルジグリコールアセテート
・ＭＥＫ：メチルエチルケトン The abbreviations in the table are as follows:
CCR-1171H: Cresol novolac epoxy acrylate (manufactured by Nippon Kayaku Co., Ltd., acid value 99 mg KOH/g, solid content concentration approximately 60%, weight average molecular weight 7500)
CCR-1373H: Cresol novolac type epoxy acrylate (manufactured by Nippon Kayaku Co., Ltd., acid value 99 mg KOH/g, solid content concentration approximately 60%, weight average molecular weight 2800)
ZCR-1797H: Biphenyl type epoxy acrylate (manufactured by Nippon Kayaku Co., Ltd., acid value 99 mg KOH/g, solid content concentration approximately 60%, weight average molecular weight 6500)
ZCR-8001H: Biphenyl type epoxy acrylate (manufactured by Nippon Kayaku Co., Ltd., acid value 109 mg KOH/g, solid content concentration approximately 60%, weight average molecular weight 3700)
CCR-1224H: Cresol novolac epoxy acrylate (manufactured by Nippon Kayaku Co., Ltd., acid value 99 mg KOH/g, solid content concentration approximately 60%, weight average molecular weight 8700)
Naphthol aralkyl type (1000): naphthol aralkyl type epoxy acrylate (1000) synthesized in Synthesis Example 1
Omnipol 910: a compound represented by the following structure (manufactured by IGM, molecular weight of 850 or more) in which d represents an integer of 1 to 10.

Omnipol TP: a compound represented by the following structure (manufactured by IGM, molecular weight 900 or more) In the formula, a, b, and c each represent an integer of 1 to 10.

・Omnirad379EG: (manufactured by IGM, molecular weight 380.5)

Omnirad TPO: (manufactured by IGM, molecular weight 348)

NC3000H: biphenyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 271 g/eq.)
SO-C2: inorganic filler (spherical silica, manufactured by Admatechs, average particle size 0.5 μm, specific surface area 6 m ² /g)
DPHA: Dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.)
EDG-Ac: Ethyl diglycol acetate MEK: Methyl ethyl ketone

In each example, it has been confirmed that even when components (C) to (F) are not included, the results are similar to those of the above examples, although to a lesser extent.

Claims (10)

(A-1) a resin containing an ethylenically unsaturated group and a carboxyl group, the resin having a weight average molecular weight of 6,000 or less;
(A-2) a resin containing an ethylenically unsaturated group and a carboxyl group and having a weight average molecular weight 2,000 or more larger than that of the component (A-1), and (B) a photopolymerization initiator;
the component (A-1) and the component (A-2) each have a cresol novolak skeleton, a bisphenol A skeleton, a bisphenol F skeleton, a biphenyl skeleton, or a naphthol aralkyl skeleton;
The component (B) has a structural unit represented by the following formula (B-1):
A photosensitive resin composition, in which the molecular weight of component (B) is 400 or more.

(In formula (B-1), R ¹ represents an actinic ray absorbing group, and each R ² independently represents a divalent hydrocarbon group. n represents an integer of 1 to 10. * represents a bond.) The photosensitive resin composition according to claim 1, wherein the molecular weight of component (B) is 700 or more. The photosensitive resin composition according to claim 1 or 2 , further comprising (C) an inorganic filler. 4. The photosensitive resin composition according to claim 3 , wherein the content of the component (C) is 1% by mass or more, based on 100% by mass of nonvolatile components in the photosensitive resin composition. The photosensitive resin composition according to any one of claims 1 to 4 , wherein the component (A-1) and the component (A-2) contain an acid-modified cresol novolac skeleton-containing epoxy (meth)acrylate. The photosensitive resin composition according to any one of claims 1 to 5 , which is used for forming a solder resist. A supported photosensitive film comprising a support and a photosensitive resin composition layer provided on the support, the photosensitive resin composition layer comprising the photosensitive resin composition according to any one of claims 1 to 6 . A printed wiring board comprising an insulating layer formed from a cured product of the photosensitive resin composition according to any one of claims 1 to 6 . 9. The printed wiring board according to claim 8 , wherein the insulating layer is either an interlayer insulating material or a solder resist. A semiconductor device comprising the printed wiring board according to claim 8 or 9 .