JP7477274B2 - Photosensitive resin composition - Google Patents

Description

The present invention relates to a photosensitive resin composition. It also relates to a photosensitive film, 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

Photosensitive resin compositions for solder resists are generally required to have high resolution, insulation, and the like. In recent years, solder resists are required to have fine opening patterns that expose parts of the conductor layer having the wiring pattern in order to connect substrates by soldering, and from the viewpoint of adhesion, it is required that the opening shape of these openings does not become reverse tapered. Here, a reverse tapered opening shape refers to a shape in which the deeper the opening, the wider it becomes. In this application, the property of the opening shape not becoming reverse tapered is sometimes referred to as excellent "undercut resistance."

The object of the present invention is to provide a photosensitive resin composition that can produce a cured product with excellent undercut resistance and excellent resolution; and to provide a photosensitive film, a photosensitive film with a support, a printed wiring board, and a semiconductor device obtained using the photosensitive resin composition.

As a result of extensive research, the inventors discovered that undercut resistance and resolution can be improved by adjusting the components of the resin composition so that the weight loss rate of the photosensitive film satisfies a specific relationship, leading to the completion of the present invention.

That is, the present invention includes the following.
[1] (A) a resin containing an ethylenically unsaturated group and a carboxyl group,
(B) a photopolymerization initiator,
A photosensitive resin composition comprising: (C) an epoxy resin; and (D) a volatile component,
A photosensitive resin composition, which satisfies the relationship between the following formula (1) and formula (2), where a is a weight loss rate (%) when the photosensitive resin composition is dried at 130°C for 15 minutes, and b is a weight loss rate (%) when the photosensitive resin composition is dried at 180°C for 15 minutes.
V = ^a2 + ^b2, where V≦30 (1)
a / b ≦ 0.6 (2)
[2] The photosensitive resin composition according to [1], further comprising (F) an inorganic filler.
[3] The photosensitive resin composition according to [1] or [2], wherein the component (A) contains an acid-modified unsaturated epoxy ester resin.
[4] The photosensitive resin composition according to any one of [1] to [3], wherein the component (A) contains an acid-modified epoxy (meth)acrylate.
[5] The photosensitive resin composition according to any one of [1] to [4], wherein the component (A) contains either an acid-modified naphthalene skeleton-containing epoxy(meth)acrylate or an acid-modified bisphenol skeleton-containing epoxy(meth)acrylate.
[6] The photosensitive resin composition according to any one of [1] to [5], wherein the component (B) contains either an acylphosphine oxide-based photopolymerization initiator or an oxime ester-based photopolymerization initiator.
[7] The photosensitive resin composition according to any one of [1] to [6], wherein the component (D) has any one of a ketone and a glycol ether.
[8] A photosensitive film comprising the photosensitive resin composition according to any one of [1] to [7].
[9] 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].
[10] 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].
[11] The printed wiring board according to [10], wherein the insulating layer is a solder resist.
[12] A semiconductor device comprising the printed wiring board according to [10] or [11].

According to the present invention, it is possible to provide a photosensitive resin composition that can obtain a cured product having excellent undercut resistance and excellent resolution; and a photosensitive film, a photosensitive film with a support, a printed wiring board, and a semiconductor device obtained using the photosensitive resin composition.

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

[Photosensitive resin composition]
The photosensitive resin composition of the present invention is a photosensitive resin composition containing (A) a resin containing an ethylenically unsaturated group and a carboxyl group, (B) a photopolymerization initiator, (C) an epoxy resin, and (D) a volatile component, and satisfies the relationship between the following formulas (1) and (2), where a is the weight loss rate (%) when the photosensitive resin composition is dried at 130° C. for 15 minutes and b is the weight loss rate (%) when the photosensitive resin composition is dried at 180° C. for 15 minutes.
V = ^a2 + ^b2, where V≦30 (1)
a / b ≦ 0.6 (2)

In the present invention, by adjusting each component of the photosensitive resin composition so that the weight loss rate satisfies a predetermined relationship, a cured product with excellent undercut resistance can be obtained, and a photosensitive resin composition with excellent resolution can be provided. In addition, a cured product with excellent embedding properties can usually be obtained. The present inventors focused on the amount of volatilization of the volatile components contained in the photosensitive resin composition when heated. As a result, they found that it is possible to obtain a cured product with excellent undercut resistance when the volatilization amount when the heating temperature is 130°C and the volatilization amount when the heating temperature is 180°C satisfy the above formulas (1) and (2). It can be said that the technical idea of focusing on the volatilization amount of the volatile components and adjusting the volatile components so that the volatilization amount satisfies a predetermined relationship has not been proposed at all so far as the present inventors know.

The photosensitive resin composition may further contain optional components in combination with components (A) to (D). Examples of optional components include (E) a reactive diluent, (F) an inorganic filler, and (G) other additives. 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, as component (A), a resin containing an ethylenically unsaturated group and a carboxyl group. By including component (A) in the photosensitive resin composition, it is possible to improve developability.

Examples of ethylenically unsaturated groups include vinyl groups, allyl groups, propargyl groups, butenyl groups, ethynyl groups, phenylethynyl groups, maleimide groups, nadimide groups, and (meth)acryloyl groups. From the viewpoint of reactivity in photoradical polymerization, (meth)acryloyl groups are preferred. "(meth)acryloyl groups" refers to methacryloyl groups and acryloyl groups.

Component (A) can be any compound that has an ethylenically unsaturated group and a carboxyl group, and that allows for photoradical polymerization and alkaline development. For example, 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 epoxy group-containing copolymers, bisphenol A-type epoxy resins, hydrogenated bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, hydrogenated bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, and modified bisphenol F-type epoxy resins obtained by reacting bisphenol F-type epoxy resins with epichlorohydrin to modify them to have three or more functional groups; biphenol-type epoxy resins, such as biphenol-type epoxy resins and tetramethylbiphenol-type epoxy resins; novolac-type epoxy resins, such as phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, bisphenol A-type novolac-type epoxy resins, and alkylphenol novolac-type epoxy resins; fluorine-containing epoxy resins, such as bisphenol AF-type epoxy resins and perfluoroalkyl-type epoxy resins; naphthalene-type epoxy resins, dihydroxynaphthalene-type epoxy resins, polyhydroxybinaphthalene-type epoxy resins, naphthol-type epoxy resins, and binaphthol-type epoxy resins. 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; cyclohexanedimethanol 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.

From the viewpoint of reducing the average linear thermal expansion coefficient, the epoxy compound is preferably an epoxy group-containing copolymer or an epoxy resin containing an aromatic skeleton. Here, the term "aromatic skeleton" includes polycyclic aromatics and aromatic heterocycles. The epoxy compound is preferably an epoxy resin containing a naphthalene skeleton; an epoxy resin containing a condensed ring skeleton; a biphenyl-type epoxy resin; a bisphenol-type epoxy resin such as a bisphenol F-type epoxy resin or a bisphenol A-type epoxy resin; a cresol novolac-type epoxy resin; or a glycidyl ester-type epoxy resin.

The epoxy group-containing copolymer can be obtained by polymerizing an epoxy group-containing monomer and, if necessary, any other monomer. Examples of the epoxy group-containing monomer include epoxy group-containing (meth)acrylate monomers such as glycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 2-methyl-3,4-epoxycyclohexyl (meth)acrylate, and allyl glycidyl ether, with glycidyl (meth)acrylate being preferred. The epoxy group-containing monomer may be used alone or in a mixture of two or more kinds.

Optional monomers include, for example, styrene, (meth)acrylic acid, methyl (meth)acrylate, ethyl methacrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl methacrylate, and nonyl (meth)acrylate. , decyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, cyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, benzyl (meth)acrylate, acrylamide, N,N-dimethyl (meth)acrylamide, (meth)acrylonitrile, 3-(meth)acrylate, p) acryloylpropyltrimethoxysilane, N,N-dimethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxy-n-butyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-n-butyl (meth)acrylate, 3-hydroxy-n-butyl (meth)acrylate , 1,4-cyclohexanedimethanol mono(meth)acrylate, glycerin mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate, lactone-modified (meth)acrylate having a hydroxyl group at the end, 1-adamantyl (meth)acrylate, etc. are included, and n-butyl (meth)acrylate is preferred. The optional monomers may be used alone or in a mixture of two or more. "(meth)acrylic acid" refers to acrylic acid and methacrylic acid. "(meth)acrylate" refers to acrylate and methacrylate.

As the epoxy resin containing a naphthalene skeleton, dihydroxynaphthalene type epoxy resin, polyhydroxybinaphthalene type epoxy resin, and naphthalene type epoxy resin obtained by condensation reaction of polyhydroxynaphthalene and aldehydes are preferred. As the dihydroxynaphthalene type epoxy resin, for example, 1,3-diglycidyloxynaphthalene, 1,4-diglycidyloxynaphthalene, 1,5-diglycidyloxynaphthalene, 1,6-diglycidyloxynaphthalene, 2,3-diglycidyloxynaphthalene, 2,6-diglycidyloxynaphthalene, 2,7-diglycidyloxynaphthalene, etc. As the polyhydroxybinaphthalene type epoxy resin, for example, 1,1'-bi-(2-glycidyloxy)naphthyl, 1-(2,7-diglycidyloxy)-1'-(2'-glycidyloxy)binaphthyl, 1,1'-bi-(2,7-diglycidyloxy)naphthyl, etc. are mentioned. Examples of naphthalene-type epoxy resins obtained by the condensation reaction of polyhydroxynaphthalene with aldehydes include 1,1'-bis(2,7-diglycidyloxynaphthyl)methane, 1-(2,7-diglycidyloxynaphthyl)-1'-(2'-glycidyloxynaphthyl)methane, and 1,1'-bis(2-glycidyloxynaphthyl)methane.

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", and here the epoxy group of the epoxy compound is substantially eliminated by the reaction with (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.

When obtaining the acid-modified unsaturated epoxy ester resin, a catalyst, a solvent, a polymerization inhibitor, etc. may be used as necessary.

As the acid-modified unsaturated epoxy ester resin, an acid-modified epoxy (meth)acrylate is preferred, and it is more preferred to include either an acid-modified naphthalene skeleton-containing epoxy (meth)acrylate or an acid-modified bisphenol skeleton-containing 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 acid-modified unsaturated epoxy ester resin is preferably a (meth)acrylic polymer having a glass transition temperature of -20°C or lower. A (meth)acrylic polymer is a polymer containing structural units having a structure formed by polymerizing a (meth)acrylic monomer. Examples of such a (meth)acrylic polymer include a polymer obtained by polymerizing a (meth)acrylic monomer, or a polymer obtained by copolymerizing a (meth)acrylic monomer and a monomer that can be copolymerized with the (meth)acrylic monomer.

(Meth)acrylic polymers with a glass transition temperature of -20°C or less include acid-modified unsaturated epoxy (meth)acrylic copolymers obtained by reacting an epoxy group-containing copolymer with (meth)acrylic acid and then with an acid anhydride. In more detail, an unsaturated epoxy (meth)acrylic copolymer can be obtained by reacting an epoxy group-containing copolymer with (meth)acrylic acid, and then an acid-modified unsaturated epoxy (meth)acrylic copolymer can be obtained by reacting the unsaturated epoxy (meth)acrylic copolymer with an acid anhydride.

Preferred embodiments of the (meth)acrylic polymer with a glass transition temperature of -20°C or less include an epoxy group-containing copolymer obtained by polymerizing an epoxy group-containing monomer and an arbitrary monomer, and a compound obtained by reacting (meth)acrylic acid and an acid anhydride, in which the epoxy group-containing monomer is glycidyl methacrylate, the arbitrary monomer is butyl acrylate, and the acid anhydride is tetrahydrophthalic anhydride.

Such acid-modified unsaturated epoxy ester resins can be commercially available products, and specific examples include "ZAR-2000" (a reaction product of bisphenol A type epoxy resin, acrylic acid, and succinic anhydride), "ZFR-1491H", and "ZFR-1533H" (a reaction product of bisphenol F type epoxy resin, acrylic acid, and tetrahydrophthalic anhydride (a bisphenol F type backbone-containing acid-modified epoxy acrylate)) manufactured by Nippon Kayaku Co., Ltd., and "PR-300CP" (a reaction product of cresol novolac type epoxy resin, acrylic acid, and acid anhydride) manufactured by Showa Denko KK. These may be used alone or in combination of two or more types.

Other examples of resins containing ethylenically unsaturated groups and carboxyl groups include unsaturated modified (meth)acrylic resins in which ethylenically unsaturated groups are introduced by reacting an ethylenically unsaturated group-containing epoxy compound with a (meth)acrylic resin having structural units obtained by polymerizing (meth)acrylic acid. Examples of ethylenically unsaturated group-containing epoxy compounds include glycidyl methacrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and 3,4-epoxycyclohexylmethyl (meth)acrylate. It is also possible to react an acid anhydride with the hydroxyl group generated during the introduction of the unsaturated group. The acid anhydride may be the same as the acid anhydride described above, and the preferred range is also the same.

Such unsaturated modified (meth)acrylic resins can be commercially available products, and specific examples include "SPC-1000" and "SPC-3000" manufactured by Showa Denko K.K., and "Cyclomer P(ACA)Z-250", "Cyclomer P(ACA)Z-251", "Cyclomer P(ACA)Z-254", "Cyclomer P(ACA)Z-300", and "Cyclomer P(ACA)Z-320" manufactured by Daicel Allnex Co., Ltd.

From the viewpoint of film-forming properties, the weight average molecular weight of component (A) is preferably 1000 or more, more preferably 1500 or more, and even more preferably 2000 or more. From the viewpoint of developability, the upper limit is preferably 10000 or less, more preferably 8000 or less, and even more preferably 7500 or less. The weight average molecular weight is the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

The acid value of the (A) component is preferably 0.1 mgKOH/g or more, more preferably 0.5 mgKOH/g or more, and even more preferably 1 mgKOH/g or more, from the viewpoint of improving the alkaline developability of the photosensitive resin composition. On the other hand, from the viewpoint of suppressing the fine pattern of the cured product from dissolving due to 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 weighing out 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, which is an indicator, is added to the solution, and titration is performed using a 0.1 N KOH aqueous solution. Then, the acid value is calculated by the following formula.
Formula: A(b)=10×Vf×56.1/(Wp×I)

In the above formula, A(b) represents the acid value (mgKOH/g), Vf represents the titration amount of KOH (mL), Wp represents the mass of the measured resin solution (g), and I represents the proportion of non-volatile matter in the measured resin solution (mass%).

In the production of component (A), 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 1:0.8-1.3, and more preferably in the range of 1:0.9-1.2.

From the viewpoint of improving flexibility, the glass transition temperature (Tg) of the component (A) is preferably −300° C. or higher, more preferably −200° C. or higher, and even more preferably −80° C. or higher, and is preferably −20° C. or lower, more preferably −23° C. or lower, and even more preferably −25° C. or lower. Here, the glass transition temperature of the component (A) is the theoretical glass transition temperature of the main chain of the component (A), and this theoretical glass transition temperature can be calculated by the FOX formula shown below. The glass transition temperature calculated by the FOX formula is almost the same as the glass transition temperature measured by differential scanning calorimetry (TMA, DSC, DTA), so the glass transition temperature of the main chain of the component (A) may be measured by differential scanning calorimetry.
1/Tg=(W1/Tg1)+(W2/Tg2)+...+(Wm/Tgm)
W1+W2+...+Wm=1
Wm represents the content (mass%) of each monomer constituting component (A), and Tgm represents the glass transition temperature (K) of each monomer constituting component (A).

From the viewpoint of improving alkaline developability, the (A) component is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, when the non-volatile components in the photosensitive resin composition are taken as 100% by mass. From the viewpoint of improving heat resistance and average linear expansion coefficient, the upper limit is preferably 40% by mass or less, more preferably 35% by mass or less, even more preferably 35% by mass or less, 30% by mass or less, or 25% 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.

<(B) Photopolymerization initiator>
The photosensitive resin composition contains a photopolymerization initiator as component (B). By including the photopolymerization initiator (B) in the photosensitive resin composition, the photosensitive resin composition can be efficiently photocured.

(B) Any compound can be used as the photopolymerization initiator, for example, acylphosphine oxide-based photopolymerization initiators such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide) and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide; oxime ester-based photopolymerization initiators such as 1,2-octanedione, 1-4-(phenylthio)-2-(O-benzoyloxime), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, and 1-(O-acetyloxime); 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-[4-(4-morpholinyl)phenyl]-1-butanone, and 2-methyl-1-[4-(methylthio)phenyl]-2-mol Examples of the photopolymerization initiator include α-aminoalkylphenone-based photopolymerization initiators such as holinopropan-1-one; benzophenone, methylbenzophenone, o-benzoylbenzoic acid, benzoyl ethyl ether, 2,2-diethoxyacetophenone, 2,4-diethylthioxanthone, diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl-(2,4,6-trimethylbenzoyl)phenylphosphinate, 4,4'-bis(diethylamino)benzophenone, 1-hydroxy-cyclohexyl-phenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxand; and sulfonium salt-based photopolymerization initiators. These may be used alone or in combination of two or more. Among these, from the viewpoint of more efficiently photocuring the photosensitive resin composition, either an acylphosphine oxide-based photopolymerization initiator or an oxime ester-based photopolymerization initiator is preferred, and an oxime ester-based photopolymerization initiator is more preferred. These may be used alone or in combination of two or more.

(B) Specific examples of photopolymerization initiators include "Omnirad 907", "Omnirad 369", "Omnirad 379", "Omnirad 819", and "Omnirad TPO" manufactured by IGM, "Irgacure OXE-01", "Irgacure OXE-02", "Irgacure TPO", and "Irgacure 819" manufactured by BASF, and "N-1919" manufactured by ADEKA.

Furthermore, the photosensitive resin composition may contain, in combination with the photopolymerization initiator (B), tertiary amines such as N,N-dimethylaminobenzoic acid ethyl ester, N,N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, triethanolamine, etc., as photopolymerization initiator assistants, or may contain photosensitizers such as pyrazonides, anthracenes, coumarins, xanthones, thioxanthones, etc. Any of these may be used alone or in combination of two or more.

The content of the photopolymerization initiator (B) is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and even more preferably 0.01% by mass or more, when the non-volatile components of the photosensitive resin composition are taken as 100% by mass, from the viewpoint of sufficiently photocuring the photosensitive resin composition and improving insulation reliability. On the other hand, from the viewpoint of suppressing a decrease in resolution due to excessive sensitivity, the upper limit is preferably 3% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less. In addition, when the photosensitive resin composition contains a photopolymerization initiator assistant, it is preferable that the total content of the photopolymerization initiator (B) and the photopolymerization initiator assistant is within the above range.

<(C) Epoxy Resin>
The photosensitive resin composition contains an epoxy resin as component (C). By containing component (C), the insulation reliability can be improved. However, component (C) does not include an epoxy resin containing an ethylenically unsaturated group and a carboxyl group.

Examples of the (C) component 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, etc. The (C) epoxy resins may be used alone or in combination of two or more types.

The photosensitive resin composition preferably contains, as component (C), an epoxy resin having two or more epoxy groups in one molecule. From the viewpoint of significantly obtaining the desired effect 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 (C) is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more.

Component (C) includes 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 as component (C), only solid epoxy resins, or a combination of liquid and 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 naphthalene 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 epoxy resin). diene type epoxy resin); "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", and "HP6000" (naphthylene ether type epoxy resin) manufactured by DIC Corporation; "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", and "NC3000" manufactured by Nippon Kayaku Co., Ltd. "L", "NC3100" (biphenyl type epoxy resin); "ESN475V" (naphthol type epoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; "ESN485" (naphthol novolac type epoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; "YX4000H", "YX4000", "YL6121" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX4000HK" (bixylenol type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "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; "jER1031S" (tetrakishydroxyphenylethane 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, with bisphenol A type epoxy resins and bisphenol F type epoxy resins being more preferable.

Specific examples of liquid epoxy resins include DIC's "HP4032", "HP4032D", and "HP4032SS" (naphthalene type epoxy resins); Mitsubishi Chemical's "828US", "jER828EL", "825", and "Epicoat 828EL" (bisphenol A type epoxy resins); Mitsubishi Chemical's "jER807" and "1750" (bisphenol F type epoxy resins); Mitsubishi Chemical's "jER152" (phenol novolac type epoxy resin); Mitsubishi Chemical's "630" and "630LSD" (glycidylamine type epoxy resins). Examples of such epoxy resins include "ZX1059" manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd. (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin); "EX-721" manufactured by Nagase ChemteX Corporation (glycidyl ester type epoxy resin); "Celloxide 2021P" manufactured by Daicel Corporation (alicyclic epoxy resin having an ester skeleton); "PB-3600" manufactured by Daicel Corporation (epoxy resin having a butadiene structure); and "ZX1658" and "ZX1658GS" manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd. (liquid 1,4-glycidylcyclohexane type epoxy resin). These may be used alone or in combination of two or more types.

When a liquid epoxy resin and a solid epoxy resin are used in combination as component (C), the ratio by mass (liquid epoxy resin:solid epoxy resin) is preferably 1:1 to 1:20, more preferably 1:1.5 to 1:15, and particularly preferably 1:2 to 1:10. By keeping the ratio by mass of the liquid epoxy resin to the solid epoxy resin within this range, the desired effects of the present invention can be significantly obtained.

The epoxy equivalent of component (C) 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 the component (C) is preferably 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500, from the viewpoint of prominently obtaining the desired effects of the present invention.
The weight average molecular weight of the resin can be measured by gel permeation chromatography (GPC) as a polystyrene equivalent value.

The content of component (C) is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, when the non-volatile components in the resin composition are taken as 100% by mass, from the viewpoint of obtaining an insulating layer that exhibits good tensile mechanical strength and insulating reliability. The upper limit of the content of component (C) is preferably 20% by mass or less, more preferably 15% by mass or less, and particularly preferably 12% by mass or less, from the viewpoint of significantly obtaining the desired effects of the present invention.

<(D) Volatile Components>
The photosensitive resin composition contains a volatile component as component (D). By adding component (D) to the photosensitive resin composition so as to satisfy formula (1) and formula (2), a cured product having excellent undercut resistance can be obtained. In addition, by adding component (D) to the photosensitive resin composition, the varnish viscosity of the photosensitive resin composition can be adjusted.

(D) Examples of the volatile component include solvents such as organic solvents. Organic solvents also include the organic solvents in the organic solvent solution containing components (A) to (C), (E) or (G) when preparing the photosensitive resin composition.

Examples of such solvents include ketones such as ethyl methyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, carbitol acetate, and ethyl diglycol acetate; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha; and the like. These may be contained alone or in combination of two or more. Among them, it is preferable that the solvent contains either ketones or glycol ethers from the viewpoint of obtaining a cured product with excellent undercut resistance.

From the viewpoint of obtaining a cured product with excellent undercut resistance, it is preferable to use a mixture of a high-boiling organic solvent and a low-boiling organic solvent as the volatile component (D). The high-boiling organic solvent has a boiling point of preferably 100°C or higher, more preferably 120°C or higher, and even more preferably 150°C or higher. The upper limit is not particularly limited, but may be 300°C or lower. The low-boiling organic solvent has a boiling point of preferably less than 100°C, more preferably 90°C or lower, and even more preferably 85°C or lower. The lower limit is not particularly limited, but may be 30°C or higher.

(D) The content of the volatile components can be adjusted to satisfy formula (1) and formula (2).

<(E) Reactive Diluent>
In addition to the above-mentioned components, the photosensitive resin composition may further contain a reactive diluent as an optional component (E). However, the component (E) does not include the component (A). By including the reactive diluent (E) in the photosensitive resin composition, the photoreactivity can be improved. As the component (E), for example, a photosensitive (meth)acrylate compound that has one or more (meth)acryloyl groups in one molecule and is liquid, solid or semi-solid at room temperature can be used. Room temperature refers to about 25°C.

Examples of photosensitive (meth)acrylate compounds include 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 (E) reactive diluent is, from the viewpoint of promoting photocuring, preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and preferably 25% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, when the total solid content of the photosensitive resin composition is taken as 100% by mass.

<(F) Inorganic Filler>
In addition to the above-mentioned components, the photosensitive resin composition may further contain an inorganic filler as an optional component (F).

(F) An inorganic compound is used as the material of the inorganic filler. Examples of the material of the inorganic filler 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 magnesium hydroxide are preferred, and silica is particularly preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. In addition, spherical silica is preferred as the silica. (F) The inorganic filler may be used alone or in combination of two or more types.

Commercially available products of component (F) include, for example, "UFP-20" and "UFP-30" manufactured by Denka; "SP60-05" and "SP507-05" manufactured by Nippon Steel & Sumitomo Metal Materials; "SC2050", "YC100C", "YA050C", "YA050C-MJE", "YA010C", "SC2500SQ", "SO-C4", "SO-C2", and "SO-C1" manufactured by Admatechs; "Silfil NSS-3N", "Silfil NSS-4N", and "Silfil NSS-5N" manufactured by Tokuyama Corporation; and "EP4-A" manufactured by Konoshima Chemical Co., Ltd.

The specific surface area of component (F) is preferably 1 m ² /g or more, more preferably 2 m ² /g or more, and particularly preferably 3 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.

From the viewpoint of significantly obtaining the desired effects of the present invention, the average particle size of component (F) is preferably 0.01 μm or more, more preferably 0.05 μm or more, and particularly preferably 0.1 μm or more, and is preferably 5 μm or less, more preferably 2 μm or less, and even more preferably 1 μm or less.

The average particle size of component (F) 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 used as the average particle size. The measurement sample can be prepared by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing the mixture ultrasonically for 10 minutes. The measurement sample is measured using a laser diffraction particle size distribution measuring device with blue and red light wavelengths as the light source, and the volume-based particle size distribution of component (F) is measured using a flow cell method, and the average particle size can be calculated as the median diameter from the particle size distribution obtained. An example of a laser diffraction particle size distribution measuring device is the "LA-960" manufactured by Horiba, Ltd.

From the viewpoint of improving moisture resistance and dispersibility, it is preferable that the (F) component is treated with a surface treatment agent. Examples of the surface treatment agent include vinylsilane coupling agents, (meth)acrylic coupling agents, fluorine-containing silane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, alkoxysilanes, organosilazane compounds, and titanate coupling agents. Among them, from the viewpoint of obtaining the effects of the present invention significantly, vinylsilane coupling agents, (meth)acrylic coupling agents, and aminosilane coupling agents are preferred. Moreover, the surface treatment agent may be used alone or in any combination of two or more types.

Commercially available surface treatment agents include, for example, Shin-Etsu Chemical Co., Ltd.'s "KBM1003" (vinyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM503" (3-methacryloxypropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM403" (3-glycidoxypropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM803" (3-mercaptopropyltrimethoxysilane), and Shin-Etsu Chemical Co., Ltd.'s "KBE903" (3-aminopropyltriethoxy silane), Shin-Etsu Chemical Co., Ltd.'s "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd.'s "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy-type silane coupling agent), Shin-Etsu Chemical Co., Ltd.'s "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane), etc.

From the viewpoint of improving the dispersibility of the inorganic filler, it is preferable that the degree of surface treatment with the surface treatment agent falls within a specified range. Specifically, 100 parts by mass of the inorganic filler is preferably surface-treated with 0.2 parts by mass to 5 parts by mass of the surface treatment agent, more preferably with 0.2 parts by mass to 3 parts by mass, and more preferably with 0.3 parts by mass to 2 parts by mass.

The degree of surface treatment by the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of the inorganic filler is preferably 0.02 mg/m ² or more, more preferably 0.1 mg/m ² or more, and even more preferably 0.2 mg/m ² or more. On the other hand, from the viewpoint of suppressing the increase in the melt viscosity of the resin varnish and the melt viscosity in the sheet form, it is preferably 1 mg/m ² or less, more preferably 0.8 mg/m ² or less, and even more preferably 0.5 mg/m ² or less.

The amount of carbon per unit surface area of the inorganic filler can be measured after the surface-treated inorganic filler is washed with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solids, the amount of carbon per unit surface area of the inorganic filler can be measured using a carbon analyzer. An example of a carbon analyzer that can be used is the "EMIA-320V" manufactured by Horiba, Ltd.

From the viewpoint of obtaining a significant effect of the present invention, the content of component (F) is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, when the non-volatile components in the photosensitive resin composition are taken as 100% by mass.

<(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 by mixing the above essential components (A) to (D) and the above optional components (E) to (G), and kneading or stirring the mixture as necessary using a kneading device such as a triple roll mill, ball mill, bead mill, or sand mill, or a stirring device such as a super mixer or planetary mixer.

<Properties and Applications of Photosensitive Resin Composition>
The weight loss rate (%) when the photosensitive resin composition is dried at 130 ° C for 15 minutes is defined as a. The weight loss rate (%) when the photosensitive resin composition is dried at 180 ° C for 15 minutes is defined as b. At this time, by satisfying the relationship between formula (1) and formula (2), it is possible to obtain a cured product having excellent undercut resistance, and improve the resolution. The photosensitive resin composition may be a layered photosensitive resin composition layer that satisfies the relationship between formula (1) and formula (2) during the exposure step. For example, a photosensitive resin composition layer formed on a support, or a photosensitive resin composition layer formed after directly applying and drying a photosensitive resin composition on a circuit board, etc. can be mentioned.
V = ^a2 + ^b2, where V≦30 (1)
a / b ≦ 0.6 (2)

The weight reduction rate a (%) here is a value calculated from the following formula (A) by cutting the photosensitive film with the support after applying and drying the resin varnish on the support to 10 cm x 10 cm, leaving it in a desiccator for 30 minutes, taking the mass (g) of the photosensitive film with the support as (a1), and then heating the photosensitive film with the support for 15 minutes in an oven at 130 ° C. as (a2). The weight reduction rate b (%) here is a value calculated from the following formula (B) by cutting the photosensitive film with the support after applying and drying the resin varnish on the support to 10 cm x 10 cm, leaving it in a desiccator for 30 minutes, taking the mass (g) of the photosensitive film with the support as (b1), and then heating the photosensitive film with the support for 15 minutes in an oven at 180 ° C. as (b2). In addition, the "mass (g) of the support" in formulas (A) and (B) represents the mass (g) of the support after the support is cut into a size of 10 cm x 10 cm and left in a desiccator for 30 minutes.

From the viewpoint of obtaining a cured product having excellent undercut resistance and improving resolution, V in formula (1) is 30 or less, preferably 28 or less, more preferably 27 or less, and even more preferably 26 or less. From the viewpoint of obtaining a significant effect of the present invention, the lower limit of V in formula (1) is preferably 1 or more, more preferably 3 or more, and even more preferably 5 or more.

In order to obtain a cured product having excellent undercut resistance and to improve resolution, a/b in formula (2) is 0.6 or less, preferably 0.55 or less, more preferably 0.5 or less, and even more preferably 0.48 or less. In order to obtain the effects of the present invention significantly, the lower limit of a/b in formula (2) is preferably 0.01 or more, more preferably 0.05 or more, and even more preferably 0.1 or more.

The photosensitive resin composition of the present invention exhibits the characteristic that the cured product obtained by photocuring the photosensitive resin composition of the present invention has excellent resolution. Therefore, there is no residue at the bottom of a round hole (via) with an opening diameter of 100 μm. The via bottom residue can be evaluated according to the method described below in <Evaluation of via bottom residue and undercut resistance>.

The cured product obtained by photocuring the photosensitive resin composition of the present invention exhibits excellent undercut resistance. In other words, it results in an insulating layer and a solder resist that have excellent undercut resistance. The undercut is preferably 5 μm or less, more preferably 4 μm or less, and even more preferably 3 μm or less. There is no particular limit to the lower limit, but it can be 0.1 μm or more. The undercut can be measured according to the method described below in <Evaluation of residue at the bottom of vias and undercut resistance>.

The photosensitive resin composition of the present invention exhibits excellent embeddability. In a specific example of measuring embeddability, a photosensitive film is laminated onto an inner layer circuit board (conductor thickness 18 μm, thickness 0.8 mm). The appearance of the inner layer circuit board laminated with the photosensitive film is visually observed for the presence or absence of voids. The number of voids is usually 0. Details of the evaluation of embeddability can be measured according to the method described in the examples below.

The photosensitive resin composition of the present invention exhibits the characteristic of having a low melt viscosity. The melt viscosity is preferably 100 poise or more, more preferably 500 poise or more, even more preferably 1000 poise or more, and preferably 20000 poise or less, more preferably 15000 poise or less, even more preferably 10000 poise or less. The melt viscosity 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, 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, it 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), 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]
The photosensitive resin composition of the present invention can be made into a photosensitive film by forming a photosensitive resin composition layer by applying a resin varnish containing the photosensitive resin composition onto a supporting substrate and drying it. Also, the photosensitive film can be made by applying the resin varnish onto a support and drying it. That is, the photosensitive film of the present invention contains the photosensitive resin composition of the present invention. The supporting substrate mainly includes a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a thermosetting polyphenylene ether substrate, and the like.

Examples of methods for applying resin varnish 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, spray coating, and dip coating.

The resin varnish may be applied in several separate applications, or in one application, or a combination of different methods may be used. Of 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.

The photosensitive film can be produced according to a method known to those skilled in the art, for example, by applying the photosensitive resin composition onto a support substrate or a substrate, and drying the (D) component by heating or blowing hot air. The photosensitive resin composition may be produced, for example, by using a resin varnish containing the non-volatile components of the photosensitive resin composition and an excess amount of the (D) component. Specifically, first, bubbles in the resin varnish are completely removed by a vacuum degassing method or the like, and then the resin varnish is applied onto a support substrate, and the amount of the (D) component is adjusted by drying in a hot air oven or far-infrared oven to produce a photosensitive film containing a photosensitive resin composition layer formed of the photosensitive resin composition. As an embodiment of the method for producing a photosensitive film, the resin varnish is dried at a maximum temperature of 105°C to 135°C and for a drying time of 6 minutes to 20 minutes.

The drying temperature varies depending on the curability of the photosensitive resin composition and the amount of component (D) in the resin varnish, but can be between 80°C and 120°C. However, the maximum drying temperature is preferably 105°C or higher, more preferably 110°C or higher, from the viewpoint of obtaining a cured product with excellent undercut resistance. There is no particular limit to the lower limit of the maximum temperature, but it is preferably 135°C or lower, more preferably 130°C or lower.

The drying time varies depending on the curability of the photosensitive resin composition and the amount of component (D) in the resin varnish, but is preferably 6 minutes or more, preferably 30 minutes or less, and more preferably 20 minutes or less. Here, the drying time refers to the time from when the drying temperature reaches 80°C.

The remaining amount of component (D) in the photosensitive resin composition layer is preferably 5% by mass or less, and more preferably 2% by mass or less, based on the total amount of the photosensitive resin composition layer. Those skilled in the art can set suitable drying conditions by simple experiments.

In the present invention, the photosensitive resin composition layer only needs to satisfy formula (1) and formula (2) during the exposure step, and since a cured product having excellent undercut resistance can be obtained and resolution can be improved, the thickness of the photosensitive resin composition layer is not particularly limited, but from the viewpoint of improving handleability and suppressing a decrease in sensitivity and resolution inside the photosensitive resin composition layer, the thickness is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more, and is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less.

[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 "Alphan MA-410" and "E-200C" manufactured by Oji Paper Co., Ltd., polypropylene films manufactured by Shin-Etsu Film Co., Ltd., and PS series films such as "PS-25" manufactured by Teijin Co., Ltd. In order to facilitate removal of these supports, it is preferable to apply a release agent such as a silicone coating agent to the surface. 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 preferable. Here, fisheyes are foreign matter, undissolved matter, oxidized deterioration products, etc. of the material that are taken into the film when the material is thermally melted and produced by kneading, extrusion, biaxial stretching, casting, etc.

In order to reduce light scattering during exposure to active energy 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.

The thickness of the photosensitive resin composition layer is preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more, from the viewpoint of improving handleability and suppressing a decrease in sensitivity and resolution inside the photosensitive resin composition layer, and is preferably 30 μm or less, more preferably 28 μm or less, and even more preferably 25 μm or less.

[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 or a photosensitive film with a support. Below, an example in which the insulating layer is a solder resist is described.

<Coating and drying process>
When a resin varnish containing a photosensitive resin composition is directly applied onto a circuit board, a photosensitive film is formed on the circuit board by drying and volatilizing the component (D).

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 in which a patterned conductor layer (circuit) is formed on one or both sides of the support board as described above. 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.

As a coating method, full-surface printing by screen printing is generally used, but any other coating method that can apply the coating evenly 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 common coating methods can all be used. After coating, the coating is 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. In this way, a photosensitive film is formed on the circuit board.

<Lamination process>
On the other hand, when a photosensitive film with a support is used, the photosensitive resin composition layer side is laminated on one or both sides of a circuit board using a vacuum laminator. In the lamination step, 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 pressure-bonded to the circuit board while being pressurized and heated. For a photosensitive film with a support, a method of laminating the film to a circuit board under reduced pressure by a vacuum lamination method is preferably used.

The conditions of the lamination process are not particularly limited, but for example, the lamination temperature is preferably 70°C to 140°C, the lamination pressure is preferably 1 kgf/cm ² to 11 kgf/cm ² (9.8×10 ⁴ N/m ² to 107.9×10 ⁴ N/m ² ), the lamination time is preferably 5 seconds to 300 seconds, and the air pressure is preferably 20 mmHg (26.7 hPa) or less under reduced pressure. The lamination process may be a batch process or a continuous process using a roll. 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.

<Exposure process>
After the photosensitive resin composition layer is provided on the circuit board by the coating and drying process or the lamination 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, but 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 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.

The solder resist has excellent undercut resistance because it uses the photosensitive resin composition of the present invention. Therefore, the via diameter can be preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. There is no particular lower limit, but it can be 1 μm or more, 10 μm or more, etc.

<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. 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, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

(Synthesis Example 1: Synthesis of Resin (A-1))
162 parts of 1,1'-bis(2,7-diglycidyloxynaphthyl)methane ("EXA-4700", manufactured by Dainippon Ink & Chemicals, Inc.) having an epoxy equivalent of 162 g/eq. was placed in a flask equipped with a gas inlet tube, a stirrer, a cooling tube and a thermometer, 340 parts of EDGAc (ethyl diglycol acetate, manufactured by Daicel Corporation) 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 to 105°C, and 72 parts of acrylic acid were gradually added dropwise and reacted for 16 hours. The reaction product was cooled to 80 to 90°C, and 80 parts of tetrahydrophthalic anhydride was added, reacted for 8 hours, and cooled. In this way, a resin solution having an acid value of 90 mgKOH/g of solid matter (non-volatile content 70%, hereinafter abbreviated as (A-1)) was obtained.

<Production Examples 1 and 2>
Resin materials were mixed as shown in the following recipe, and resin varnishes 1 and 2 were obtained using a high-speed rotating mixer.

The abbreviations in the table are as follows:
Component (A-1): Resin (A-1) prepared in Synthesis Example 1, ethyl diglycol acetate solution with a solid content of 70% ZFR-1491H: bis-F skeleton-containing acid-modified epoxy acrylate, manufactured by Nippon Kayaku Co., Ltd., EDGAc cut, solid content of 70%
Irgacure TPO: bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, manufactured by BASF Irgacure OXE-02: ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime), manufactured by BASF NC3000H: biphenyl type epoxy resin, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: approximately 272 g/eq.
ZX1059: a mixed epoxy resin of bisphenol A type epoxy resin and bisphenol F type epoxy resin, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., epoxy equivalent: about 165 g/eq.
1031S: Tetrakishydroxyphenylethane type epoxy resin, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent of about 200 g/eq.
EDGAc: Ethyl diglycol acetate (carbitol acetate), manufactured by Daicel Corporation, boiling point 217.4°C
MEK: Methyl ethyl ketone, Junsei Chemical Co., Ltd., boiling point 79.6°C
DPHA: dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd. EBECRYL3708: modified epoxy acrylate, manufactured by Daicel Allnex Co., Ltd. SC2050: fused silica, manufactured by Admatechs Co., Ltd., surface-treated with 0.5 parts by mass of aminosilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM573) per 100 parts by mass of average particle size 0.5 μm EP4-A: magnesium hydroxide with an average particle size of 0.8 μm surface-treated with 1 part by mass of aminosilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM573), manufactured by Konoshima Chemical Co., Ltd.

Example 1
A PET film (Toray Industries, Inc., "Lumirror T6AM", thickness 38 μm, softening point 130° C., "release PET") that had been subjected to release treatment with an alkyd resin-based 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. (maximum temperature 110° C.) for 6 minutes. Next, a cover film (biaxially oriented polypropylene film, MA-411, Oji F-Tex Co., Ltd.) was placed on the surface of the photosensitive resin composition layer and laminated at 80° C. to obtain a photosensitive film with a support having a three-layer structure of release PET, photosensitive resin composition layer, and cover film. The lamination was performed using a vacuum pressure laminator MVLP-500 manufactured by Nikko Materials Co., Ltd., by vacuum suction at a temperature of 80°C for 30 seconds, followed by pressing for 60 seconds from above the release PET via heat-resistant rubber under conditions of a temperature of 80°C and a pressure of 7.0 kg/ ^cm2 . Next, pressing was performed for 90 seconds under atmospheric pressure using a SUS end plate under conditions of a temperature of 80°C and a pressure of 5.5 kg/ ^cm2 .

<Examples 2 to 5, Comparative Examples 1 to 3>
In Example 1, the drying time and the maximum temperature during drying in obtaining a supported photosensitive film were changed to the values shown in the following table. A supported photosensitive film was obtained in the same manner as in Example 1 except for the above.

<Example 6, Comparative Example 4>
In Example 1, photosensitive resin composition 1 was changed to photosensitive resin composition 2, and the drying time and maximum temperature during drying in obtaining a supported photosensitive film were changed to the values shown in the following table. A supported photosensitive film was obtained in the same manner as in Example 1 except for the above.

<Measurement of Weight Loss Rate>
The photosensitive film with the support obtained in the examples and comparative examples was cut into 10 cm x 10 cm. These and thoroughly dried silica gel were placed in a desiccator and left for 30 minutes. After that, the mass of the photosensitive film with the support was measured with the cover film peeled off, and the value was taken as (a1) (unit: g). Next, the photosensitive film with the support was heated in an oven at 130 ° C. for 15 minutes, and the mass of the photosensitive film with the support was measured again, and the value was taken as (a2) (unit: g). The value of a (weight reduction rate when the photosensitive film with the support was dried at 130 ° C. for 15 minutes) was calculated from the above formula (A). In addition, b (weight reduction rate when the photosensitive film with the support was dried at 180 ° C. for 15 minutes) was calculated from the above formula (B) in the same manner as a, except that the oven temperature was set to 180 ° C. After calculating a and b, V and a/b were calculated.

<Melt Viscosity Measurement>
Only the photosensitive resin composition layer was peeled off from the release PET of the photosensitive film with the support, and compressed in a mold to prepare a measurement pellet (diameter 18 mm, 1.2 to 1.3 g). Using the measurement pellet, a dynamic viscoelasticity measuring device (Rheosol-G3000 manufactured by UBM Co., Ltd.) was used to measure the dynamic viscoelasticity of 1 g of the photosensitive resin composition layer of the sample, using a parallel plate with a diameter of 18 mm, from a starting temperature of 60° C. to 200° C. at a heating rate of 5° C./min, and the measurement conditions of a measurement temperature interval of 2.5° C., a frequency of 1 Hz, and a strain of 1 deg, and the minimum melt viscosity (poise) was calculated.

<Evaluation of embeddability>
An inner layer circuit board (IPC MULTI-PURPOSE TESTBOARD No. IPC-B-25, conductor thickness 18 μm, 0.8 mm thickness) was prepared. After peeling off the cover film of the photosensitive film with a support, the support-attached photosensitive film was laminated on both sides of the inner layer circuit board using a batch-type vacuum pressure laminator (manufactured by Nikko Materials Co., Ltd., VP160) so that the photosensitive resin composition layer was bonded to the inner layer circuit board. The lamination process was performed by reducing the pressure for 30 seconds to 13 hPa or less, and then pressing at 90° C. and a pressure of 0.7 MPa for 30 seconds. Next, a heat press was performed at 90° C. and a pressure of 0.5 MPa for 60 seconds.

The appearance of the inner layer circuit board after lamination was visually observed and evaluated according to the following criteria.
◯: There are no voids between the copper wirings, and the resin seeps out from the outer edge of the support to a depth of 1 cm or less.
△: A few voids are observed.
×: Resin seeps out 1 cm or more.

<Evaluation of via bottom residue and undercut resistance>
(Preparation of Laminate for Evaluation)
The copper layer of a glass epoxy substrate (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 a 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 form a laminate. The pressure bonding conditions were a vacuum drawing time of 30 seconds, a pressure bonding temperature of 90° C., a pressure bonding pressure of 0.7 MPa, and a pressure time of 30 seconds. The laminate was left at room temperature for 30 minutes or more, and exposed to ultraviolet light from the support of the laminate using a pattern forming device using a round hole pattern. The exposure pattern was an opening: a quartz glass mask that draws a round hole (via) of 100 μm. After leaving it at room temperature for 30 minutes, the support was peeled off from the laminate. A 1% by mass aqueous solution of sodium carbonate at 30°C was used as a developer on the entire surface of the photosensitive resin composition layer on the laminate, and spray development was performed for 2 minutes at a spray pressure of 0.2 MPa. After spray development, the laminate was irradiated with ultraviolet light at 1 J/ ^cm2 and further heated at 180°C for 30 minutes to form an insulating layer having an opening on the laminate. This was used as a laminate for evaluation.

(Evaluation of via bottom residue)
The evaluation was performed according to the following criteria for a 100 μm round hole formed in the evaluation laminate.
A: No residue.
×: Residue was observed.

(Evaluation of undercut resistance)
A cross section of a 100 μm round hole formed in the evaluation laminate was observed using an SEM, and the radius (μm) of the top and bottom of the cross section was measured, and the difference (radius of the top - radius of the bottom) was calculated.

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

Claims (11)

A photosensitive film containing a photosensitive resin composition,
The photosensitive resin composition comprises:
(A) a resin containing an ethylenically unsaturated group and a carboxyl group,
(B) a photopolymerization initiator,
(C) an epoxy resin; and (D) a volatile component.
(D) the volatile component is at least one selected from the group consisting of ethyl diglycol acetate and methyl ethyl ketone;
A photosensitive film, wherein the photosensitive resin composition satisfies the following formula (1) and formula (2):
V = a2 ⁺ b2 ^, where V≦30 (1)
a / b ≦ 0.6 (2)
However, ( D) a photosensitive resin composition layer having a volatile component content of 5 mass% or less, a thickness of 25 μm after drying, and a size of 10 cm × 10 cm on a PET film is
The weight loss rate (%) when dried in an oven at 130° C. for 15 minutes is defined as a ,
The weight loss rate (%) when dried in an oven at 180 °C for 15 minutes is defined as b. The photosensitive film according to claim 1, further comprising (F) an inorganic filler. The photosensitive film according to claim 1 or 2, wherein component (A) contains an acid-modified unsaturated epoxy ester resin. The photosensitive film according to any one of claims 1 to 3, wherein component (A) contains an acid-modified epoxy (meth)acrylate. The photosensitive film according to any one of claims 1 to 4, wherein component (A) contains either an acid-modified naphthalene skeleton-containing epoxy (meth)acrylate or an acid-modified bisphenol skeleton-containing epoxy (meth)acrylate. The photosensitive film according to any one of claims 1 to 5, wherein component (B) contains either an acylphosphine oxide-based photopolymerization initiator or an oxime ester-based photopolymerization initiator. The photosensitive film according to any one of claims 1 to 6, wherein component (D) is ethyl diglycol acetate and methyl ethyl ketone. A photosensitive film with a support, comprising a support and the photosensitive film according to any one of claims 1 to 7 provided on the support. A printed wiring board comprising an insulating layer that is a cured product of the photosensitive film according to any one of claims 1 to 7. The printed wiring board according to claim 9, wherein the insulating layer is a solder resist. A semiconductor device including the printed wiring board according to claim 9 or 10.