WO2022211122A1

WO2022211122A1 - Laminated structure, dry film, cured product, and electronic component

Info

Publication number: WO2022211122A1
Application number: PCT/JP2022/016969
Authority: WO
Inventors: ハヌルチャ; 大地岡本; 英和宮部
Original assignee: 太陽インキ製造株式会社
Priority date: 2021-03-31
Filing date: 2022-03-31
Publication date: 2022-10-06
Also published as: KR20230165788A; JPWO2022211122A1; CN117120930A

Abstract

Provide a laminated structure which has excellent crack resistance, has good patterning properties, and can be removed without residue in a development step.　The laminated structure has a dual-layered resin layer obtained by laminating a resin layer (A) formed from a resin composition (a) and a resin layer (B) formed from a resin composition (b). The resin composition (b) of the resin layer (B) comprises an alkali-soluble resin, a photo-base generator that also functions as a photopolymerization initiator or a photopolymerization initiator and a photo-base generator, and a thermosetting resin. The resin composition (a) of the resin layer (A) contains a carboxyl group-containing resin and a thermosetting resin, and does not substantially contain a photopolymerization initiator. The 150°C gelling time of a mixture of the thermosetting resin and the alkali-soluble resin contained in the resin composition (b) of the resin layer (B) is 120-600 seconds. The 150°C gelling time of a mixture of the thermosetting resin and the carboxyl group-containing resin contained in the resin composition (a) of the resin layer (A) is 300-1200 seconds, and is longer than the gelling time of the mixture of the resin layer (B).

Description

Laminated structures, dry films, cured products and electronic components

The present invention relates to laminated structures, dry films, cured products suitable for use in semiconductor packages and the like, and electronic components using these.

In recent years, in response to the increased density of printed wiring boards that accompanies the miniaturization of electronic equipment, workability and higher performance are also required for solder resists. In recent years, as electronic devices have become smaller, lighter, and have higher performance, miniaturization and multi-pin semiconductor packages have been put to practical use, and mass production is progressing. Various semiconductor packages have been proposed to cope with such high density.

In recent years, there has been a demand for solder resists used in various high-density semiconductor packages to have both high reliability in the usage environment and long-term reliability. Biased HAST (hereinafter referred to as B-HAST) is one of the reliability tests related to reliability in the usage environment, and crack resistance in thermal cycles is one of the long-term reliability tests. I have an exam. With respect to a photocurable / thermosetting resin composition excellent in B-HAST resistance, a compound (a) having two or more phenolic hydroxyl groups in one molecule and an alkylene oxide (b) or a cyclocarbonate compound (c) A carboxyl group-containing photosensitive resin obtained by reacting the reaction product obtained by reacting an unsaturated group-containing monocarboxylic acid (d) and reacting the resulting reaction product with a polybasic acid anhydride (e) There is a resin composition containing (Patent Document 1).

Japanese Patent No. 5183073

Since the resin composition described in Cited Document 1 contains a carboxyl group-containing photosensitive resin having a rigid skeleton, it is excellent in B-HAST resistance. was not always sufficient.

Instead of the carboxyl group-containing photosensitive resin having a rigid skeleton, attempts have been made to make a resin composition containing a resin having a more flexible skeleton, such as a carboxyl group-containing urethane resin, and a photobase generator. Furthermore, it was found that the characteristics can be improved by forming a laminated structure in which a plurality of layers having different compositions are laminated.
However, in order to obtain good patterning properties in a laminated structure using a photobase generator, a heating step is required after exposure for the purpose of promoting the thermal reaction between the carboxylic acid and the epoxy in the exposed area. At that time, the problem was how to suppress the reaction between the carboxylic acid and the epoxy in the unexposed area as much as possible and remove it without residue in the development process.

Accordingly, an object of the present invention is to provide a laminate structure, a dry film, a cured product, and an electronic component that are excellent in crack resistance, have good patterning properties, and can be removed without residue in the development process.

The laminate structure of the present invention is a laminate having two resin layers in which a resin layer (A) made of the resin composition (a) and a resin layer (B) made of the resin composition (b) are laminated. is a struct,
The resin composition (b) of the resin layer (B) comprises an alkali-soluble resin, a photobase generator or a photopolymerization initiator and a photobase generator having the function of a photopolymerization initiator, a thermosetting resin, including
The resin composition (a) of the resin layer (A) contains a carboxyl group-containing resin and a thermosetting resin and does not substantially contain a photopolymerization initiator,
The mixture of the alkali-soluble resin and the thermosetting resin contained in the resin composition (b) of the resin layer (B) has a gelation time at 150° C. of 120 seconds or more and 600 seconds or less,
The mixture of the carboxyl group-containing resin and the thermosetting resin contained in the resin composition (a) of the resin layer (A) has a gelation time at 150° C. of 300 seconds or more and 1200 seconds or less, and It is characterized by being longer than the gelation time in the mixture of the resin layer (B).

In the laminated structure, the thickness of the resin layer (B) is 2 μm or more and not more than half the thickness of the resin layer (A), and the thickness of the resin layer (A) is 10 to 80 μm. is preferred, and 20 to 60 μm is more preferred.

Further, the dry film of the present invention is in contact with the laminated structure of the present invention and at least one surface of the surface of the resin layer (B) and the surface of the resin layer (A) of the laminated structure. and a film provided.

Furthermore, the cured product of the present invention is characterized by being obtained by curing the laminated structure of the present invention or the laminated structure of the dry film of the present invention.

The electronic component of the present invention is characterized by having the cured product of the present invention.

According to the present invention, there are provided a laminated structure, a dry film, a cured product thereof, and an electronic component using the cured product, which have excellent crack resistance, good patterning properties, and can be removed without residue in a development process. can provide.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the laminated structure, dry film, cured product and electronic component of the present invention will be described in detail.
(Laminate structure)
The laminate structure of the present invention is a laminate having two resin layers in which a resin layer (A) made of the resin composition (a) and a resin layer (B) made of the resin composition (b) are laminated. is a struct,
The resin composition (b) of the resin layer (B) comprises an alkali-soluble resin, a photobase generator or a photopolymerization initiator and a photobase generator having the function of a photopolymerization initiator, a thermosetting resin, including
The resin composition (a) of the resin layer (A) contains a carboxyl group-containing resin and a thermosetting resin and does not substantially contain a photopolymerization initiator,
The mixture of the alkali-soluble resin and the thermosetting resin contained in the resin composition (b) of the resin layer (B) has a gelation time at 150° C. of 120 seconds or more and 600 seconds or less,
The mixture of the carboxyl group-containing resin and the thermosetting resin contained in the resin composition (a) of the resin layer (A) has a gelation time at 150° C. of 300 seconds or more and 1200 seconds or less, and It is characterized by being longer than the gelling time in the mixture of the resin composition (b) of the resin layer (B).

When the laminated structure is formed on a substrate, the layer in contact with the substrate is the resin layer (A), and the surface of the resin layer (A) opposite to the surface in contact with the substrate is in contact with the substrate. This layer is the resin layer (B). That is, the laminated structure has a structure in which the resin layer (A) and the resin layer (B) are laminated in this order on the substrate. Examples of the base material include a printed wiring board, a flexible printed wiring board, and the like on which a circuit is formed in advance using copper or the like.

The resin composition (b) of the resin layer (B) comprises an alkali-soluble resin, a photobase generator or a photopolymerization initiator and a photobase generator having the function of a photopolymerization initiator, and a thermosetting resin. It consists of a resin composition containing The resin composition (b) of the resin layer (B) containing these components has photosensitivity due to the reaction of the photopolymerization initiator with the alkali-soluble resin by light irradiation, and the photobase of the polymerization initiator by heating. It is a photosensitive thermosetting resin composition that can be thermally cured with its function as a generator serving as a catalyst.

The resin composition (a) of the resin layer (A) is composed of a resin composition containing a carboxyl group-containing resin and a thermosetting resin and substantially free of a photopolymerization initiator. The term "substantially free of photopolymerization initiator" means that the amount of photopolymerization initiator is less than 0.5 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin contained in the resin composition (a).
Since the resin composition (a) of the resin layer (A) containing these components does not contain a photopolymerization initiator, it does not have photosensitivity in a single layer, but it is laminated in contact with the resin layer (B). Therefore, active species such as radicals generated from the photopolymerization initiator contained in the resin composition (b) of the resin layer (B) diffuse into the resin layer (A) to form the resin layer (A) is also photosensitive. Moreover, it can be thermoset by heating. Therefore, in the laminated structure, a predetermined pattern can be collectively formed on the resin layer (B) and the resin layer (A) by development. In particular, when post-exposure baking (POST EXPOSURE BAKE, hereinafter referred to as PEB) is performed, the effect of batch formation of patterns is remarkable due to thermal diffusion at that time.

If a photopolymerization initiator is contained in the resin composition (a) of the resin layer (A), the photopolymerization initiator itself has a property of absorbing light, so the photopolymerization initiator increases as it goes deeper. As a result, the polymerization initiating ability of the core is lowered, and the photoreactivity of the deep portion is lowered, which tends to cause undercutting, making it difficult to form a highly precise pattern. In contrast, in the laminated structure, the resin composition (a) of the resin layer (A) does not contain a photopolymerization initiator, and active species diffuse from the resin layer (B) to improve the undercut problem.
As a result, it is possible to form a pattern with excellent deep-part curability without undercut.

However, even if the laminated structure of the resin layer (A) and the resin layer (B) each has the above composition, the carboxylic acid in the unexposed area reacts with the epoxy during the heating process after exposure. As a result, it may become a residue in the developing process. Regarding this point, the gelation time under predetermined conditions in the mixture of the alkali-soluble resin and the thermosetting resin contained in the resin layer (B) and the resin composition (a) contained in the resin layer (A) Residue can be eliminated by adjusting the gelation time under predetermined conditions in the mixture of the carboxyl group-containing resin and the thermosetting resin.
The method for measuring the gelling time is based on the gelling time measuring method described below.

[Resin layer (A)]
(Resin composition (a) of resin layer (A))
A resin layer (A) consists of a resin composition (a). It is desirable that the resin composition (a) of the resin layer (A) not only functions as an adhesive layer with the base material, but also has properties capable of coping with formation of various circuit patterns. Therefore, the resin composition (a) of the resin layer (A) is prepared by heating a resin having a carboxyl group, especially a carboxyl group-containing resin and a thermosetting resin with a base generated from a base generator as a catalyst after exposure. It is preferably a photosensitive thermosetting resin composition that can be developed by addition reaction and removal of unexposed portions with an alkaline solution.

Various conventionally known carboxyl group-containing resins having a carboxyl group in the molecule can be used as the carboxyl group-containing resin contained in the resin composition (a) of the resin layer (A). In particular, a carboxyl group-containing photosensitive resin having an ethylenically unsaturated double bond in the molecule is preferable from the viewpoint of photocurability and development resistance. The ethylenically unsaturated double bonds are preferably derived from acrylic acid or methacrylic acid or derivatives thereof. When only a carboxyl group-containing resin having no ethylenically unsaturated double bonds is used, in order to make the composition photocurable, a compound having a plurality of ethylenically unsaturated groups in the molecule, i.e., photo It is necessary to use a reactive monomer together. Carboxyl group-containing resins may be used alone or in combination of two or more.
Specific examples of the carboxyl group-containing resin include the following compounds (both oligomers and polymers).

(1) Carboxyl group-containing resins obtained by copolymerizing unsaturated carboxylic acids such as (meth)acrylic acid and unsaturated group-containing compounds such as styrene, α-methylstyrene, lower alkyl (meth)acrylates, and isobutylene.

(2) Diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates and aromatic diisocyanates; Carboxyl group-containing urethane resins obtained by polyaddition reaction of diol compounds such as polyols, polyester-based polyols, polyolefin-based polyols, acrylic polyols, bisphenol A-based alkylene oxide adduct diols, and compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups.

(3) Diisocyanate compounds such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates, polycarbonate-based polyols, polyether-based polyols, polyester-based polyols, polyolefin-based polyols, acrylic polyols, and bisphenol A-based A terminal carboxyl group-containing urethane resin obtained by reacting an acid anhydride with the terminal of a urethane resin obtained by a polyaddition reaction of a diol compound such as an alkylene oxide adduct diol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

(4) Diisocyanate and bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin ( A carboxyl group-containing urethane resin produced by a polyaddition reaction of a meth)acrylate or its partial acid anhydride modified product, a carboxyl group-containing dialcohol compound and a diol compound.

(5) During the synthesis of the resin of (2) or (4) above, a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule such as hydroxyalkyl (meth)acrylate is added, and the terminal ( Meta) acrylated urethane resin containing carboxyl groups.

(6) During the synthesis of the resin of (2) or (4), one isocyanate group and one or more (meth)acryloyl groups in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate A carboxyl group-containing urethane resin that is terminally (meth)acrylated by adding a compound having

(7) A carboxyl group obtained by reacting a polyfunctional epoxy resin with (meth)acrylic acid and adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the hydroxyl group present in the side chain. Contained resin.

(8) A carboxyl group-containing resin obtained by reacting (meth)acrylic acid with a polyfunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of a bifunctional epoxy resin with epichlorohydrin, and adding a dibasic acid anhydride to the resulting hydroxyl groups. .

(9) A carboxyl group-containing polyester resin obtained by reacting a polyfunctional oxetane compound with a dicarboxylic acid and adding a dibasic acid anhydride to the resulting primary hydroxyl group.

(10) A reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide and reacting an unsaturated group-containing monocarboxylic acid to obtain a reaction product A carboxyl group-containing resin obtained by reacting a polybasic acid anhydride with a substance.

(11) Obtained by reacting a reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate with a monocarboxylic acid containing an unsaturated group. A carboxyl group-containing resin obtained by reacting a reaction product with a polybasic acid anhydride.

(12) an epoxy resin having a plurality of epoxy groups in one molecule, a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenethyl alcohol; Maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and A carboxyl group-containing resin obtained by reacting a polybasic acid anhydride such as adipic acid.

(13) A carboxyl group-containing resin having at least one of an amide structure and an imide structure.
(14) A maleimide or maleimide derivative such as N-phenylmaleimide or N-benzylmaleimide, an unsaturated carboxylic acid such as (meth)acrylic acid, and an unsaturated group-containing compound having a hydroxyl group such as hydroxyalkyl (meth)acrylate , styrene, α-methylstyrene, α-chlorostyrene, a carboxyl group-containing copolymer resin having an unsaturated group-containing compound having an aromatic ring such as vinyltoluene as a monomer, glycidyl (meth) acrylate, α-methyl A carboxyl group-containing photosensitive material having a copolymer structure obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in the molecule, such as glycidyl (meth)acrylate and epoxycyclohexylmethyl (meth)acrylate. synthetic resin.

(15) In addition to the carboxyl group-containing resins described in (1) to (13) above, one epoxy group and one or more ( A carboxyl group-containing resin obtained by adding a compound having a meth)acryloyl group.
In this specification, (meth)acrylate is a generic term for acrylate, methacrylate and mixtures thereof, and the same applies to other similar expressions.

Carboxyl group-containing resins are not limited to those listed above, and one type may be used alone, or a plurality of types may be mixed and used.
The acid value of the carboxyl group-containing resin is preferably 20-200 mgKOH/g.

In addition, although the weight average molecular weight of the carboxyl group-containing resin differs depending on the resin skeleton, the weight average molecular weight Mw is preferably 1,000 to 100,000.

The blending amount of the carboxyl group-containing resin is 10 to 70% by mass based on the total solid content of the resin composition. By making it 10% by mass or more, the strength of the coating film can be improved. Moreover, by making it 70% by mass or less, the viscosity becomes appropriate and the workability improves.

[Thermosetting resin]
The thermosetting resin contained in the resin composition (a) of the resin layer (A) is a resin having a functional group capable of thermal curing reaction. Thermosetting resins are not particularly limited, and include epoxy resins, oxetane compounds, compounds having two or more thioether groups in the molecule, namely amino resins such as episulfide resins, melamine resins, benzoguanamine resins, melamine derivatives, and benzoguanamine derivatives. , blocked isocyanate compounds, cyclocarbonate compounds, bismaleimides, carbodiimides and the like can be used, and these may be used in combination.

The epoxy resin is a resin having an epoxy group, and any conventionally known one can be used, including a bifunctional epoxy resin having two epoxy groups in the molecule and a polyfunctional epoxy resin having many epoxy groups in the molecule. etc. In addition, a hydrogenated bifunctional epoxy resin may be used.

Examples of epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, and cresol novolak type epoxy resin. Epoxy resins, bisphenol A novolak type epoxy resins, biphenyl type epoxy resins, naphthol type epoxy resins, naphthalene type epoxy resins, dicyclopentadiene type epoxy resins, triphenylmethane type epoxy resins, alicyclic epoxy resins, aliphatic chain Epoxy resins, phosphorus-containing epoxy resins, anthracene-type epoxy resins, norbornene-type epoxy resins, adamantane-type epoxy resins, fluorene-type epoxy resins, aminophenol-type epoxy resins, aminocresol-type epoxy resins, alkylphenol-type epoxy resins, and the like are used. These epoxy resins can be used singly or in combination of two or more.

The epoxy resin may be solid epoxy resin, semi-solid epoxy resin, or liquid epoxy resin. Here, in this specification, solid epoxy resin refers to an epoxy resin that is solid at 40°C, and semi-solid epoxy resin refers to an epoxy resin that is solid at 20°C and liquid at 40°C. A liquid epoxy resin means an epoxy resin that is liquid at 20°C.

As solid epoxy resins, EPICLON HP-4700 (naphthalene type epoxy resin) manufactured by DIC, EXA4700 (tetrafunctional naphthalene type epoxy resin) manufactured by DIC, NC-7000 (polyfunctional solid epoxy resin containing naphthalene skeleton) manufactured by Nippon Kayaku Co., Ltd. ) and other naphthalene-type epoxy resins; EPPN-502H (trisphenol epoxy resin) manufactured by Nippon Kayaku Co., Ltd. Epoxidized products of condensation products of phenols and aromatic aldehydes having phenolic hydroxyl groups (trisphenol-type epoxy resins); Dicyclopentadiene aralkyl type epoxy resin such as EPICLON HP-7200H (dicyclopentadiene skeleton-containing polyfunctional solid epoxy resin) manufactured by DIC; Biphenyl such as Nippon Kayaku NC-3000H (biphenyl skeleton-containing polyfunctional solid epoxy resin) Aralkyl-type epoxy resins; biphenyl/phenol novolac-type epoxy resins such as NC-3000L manufactured by Nippon Kayaku; EPICLON N660, EPICLON N690 manufactured by DIC; novolac-type epoxy resins such as EOCN-104S manufactured by Nippon Kayaku; biphenyl type epoxy resins such as YX-4000 manufactured by Nittetsu Chemical &Materials; phosphorus-containing epoxy resins such as TX0712 manufactured by Nippon Steel Chemical &Materials;

Semi-solid epoxy resins include EPICLON 860, EPICLON 900-IM, EPICLON EXA-4816, EPICLON EXA-4822 manufactured by DIC, Epotato YD-134 manufactured by Nippon Steel Chemical & Materials, jER834 and jER872 manufactured by Sumitomo Chemical Co., Ltd. Bisphenol A type epoxy resin such as ELA-134; naphthalene type epoxy resin such as EPICLON HP-4032 manufactured by DIC; phenol novolac type epoxy resin such as EPICLON N-740 manufactured by DIC;

Liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, glycidylamine type epoxy resin, aminophenol type epoxy resin. , and alicyclic epoxy resins.

Next, the oxetane compounds include bis[(3-methyl-3-oxetanylmethoxy)methyl]ether, bis[(3-ethyl-3-oxetanylmethoxy)methyl]ether, 1,4-bis[(3-methyl -3-oxetanylmethoxy)methyl]benzene, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, (3-methyl-3-oxetanyl)methyl acrylate, (3-ethyl-3-oxetanyl ) In addition to polyfunctional oxetanes such as methyl acrylate, (3-methyl-3-oxetanyl)methyl methacrylate, (3-ethyl-3-oxetanyl)methyl methacrylate and their oligomers or copolymers, oxetane alcohols and novolac resins, Poly(p-hydroxystyrene), cardo-type bisphenols, calixarenes, calixresorcinarenes, or etherified products with resins having a hydroxyl group such as silsesquioxane. Other examples include copolymers of unsaturated monomers having an oxetane ring and alkyl (meth)acrylates.

Examples of the episulfide resin include bisphenol A type episulfide resin. In addition, an episulfide resin or the like obtained by replacing the oxygen atom of the epoxy group of the epoxy resin with a sulfur atom by using a similar synthesis method can also be used.

Among thermosetting resins, it is preferable to use epoxy resin. Further, at least one of solid epoxy resins and semi-solid epoxy resins is preferable, since a cured product having a high glass transition temperature (Tg) and excellent crack resistance can be obtained. As the epoxy resin, aromatic epoxy resins are preferable from the viewpoint of desirable physical properties of the cured product, and among them, naphthalene-type epoxy resins and biphenyl-type epoxy resins are more preferable. In this specification, the aromatic epoxy resin means an epoxy resin having an aromatic ring skeleton in its molecule.

A thermosetting resin can be used individually by 1 type or in combination of 2 or more types. The blending ratio of the thermosetting resin is preferably 10 to 50% by mass, more preferably 15 to 45% by mass, more preferably 20 to 40% by mass, based on the total amount of the composition in terms of solid content. is more preferred.
As will be described later, it is preferable to appropriately adjust the equivalent ratio with the carboxyl group-containing resin.

[Photopolymerizable Monomer]
In the resin composition (a) of the resin layer (A), as described above, a resin having a carboxyl group and a thermosetting resin are subjected to an addition reaction by heating after exposure using a base generated from a base generator as a catalyst to form an un It is a photosensitive thermosetting resin composition that can be developed by removing the exposed portion with an alkaline solution. This eliminates the need to add a (meth)acrylate monomer, which is necessary in a photosensitive resin composition utilizing a polymerization reaction by radicals generated from a conventional photoradical polymerization initiator. However, mainly for controlling the sensitivity of the resin layer, a (meth)acrylate monomer may be blended in the resin composition of the resin layer (A). For example, about 10 to 100 parts by mass of the (meth)acrylate monomer can be blended with 100 parts by mass of the carboxyl group-containing resin.

[Resin layer (B)]
(Resin composition (b) of resin layer (B))
A resin layer (B) consists of a resin composition (b). The resin layer (B) mainly functions as a protective layer for the substrate. The resin composition (b) of the resin layer (B) is capable of radical polymerization by light due to the photopolymerization initiator, and the alkali-soluble resin and the thermosetting resin are separated by using the base generated from the base generator as a catalyst. It is a photosensitive thermosetting resin composition that undergoes an addition reaction by heating after exposure and that can be developed by removing the unexposed portion with an alkaline solution.

Examples of the alkali-soluble resin contained in the resin composition (b) of the resin layer (B) include a compound having a phenolic hydroxyl group, a compound having a carboxyl group, and a compound having a phenolic hydroxyl group and a carboxyl group. are used. In particular, carboxyl group-containing resins or carboxyl group-containing photosensitive resins, which contain a compound having a carboxyl group and are conventionally used as solder resist compositions, can be mentioned. Here, as the carboxyl group-containing resin or the carboxyl group-containing photosensitive resin and the compound having an ethylenically unsaturated bond, known and commonly used compounds are used.
Among them, as the alkali-soluble resin, an alkali-soluble resin having an imide ring, which is superior in properties such as bending resistance and heat resistance, can be preferably used. Further, as the thermosetting resin, a known and commonly used one similar to that for the resin layer (A) can be used.

(Alkali-soluble resin having imide ring)
In the present invention, the alkali-soluble resin having an imide ring has one or more alkali-soluble groups selected from phenolic hydroxyl groups and carboxyl groups, and an imide ring. A well-known and commonly used technique can be used for introducing an imide ring into this alkali-soluble resin. Examples thereof include resins obtained by reacting a carboxylic anhydride component with an amine component and/or an isocyanate component. The imidization may be carried out by thermal imidization or by chemical imidization, or these may be used in combination.

Here, examples of the carboxylic acid anhydride component include tetracarboxylic acid anhydrides and tricarboxylic acid anhydrides, but are not limited to these acid anhydrides. Any compound having a physical group and a carboxyl group can be used, including derivatives thereof. Also, these carboxylic acid anhydride components may be used alone or in combination.

As the amine component, diamines such as aliphatic diamines and aromatic diamines, polyvalent amines such as aliphatic polyetheramines, diamines having a carboxylic acid, diamines having a phenolic hydroxyl group, and the like can be used. is not limited to Also, these amine components may be used alone or in combination.

As the isocyanate component, diisocyanates such as aromatic diisocyanates and their isomers and polymers, aliphatic diisocyanates, alicyclic diisocyanates and their isomers, and other general-purpose diisocyanates can be used. It is not limited. Also, these isocyanate components may be used alone or in combination.

The alkali-soluble resin having an imide ring as explained above may have an amide bond. This may be a polyamide-imide obtained by reacting an imidized product having a carboxyl group with an isocyanate and a carboxylic acid anhydride, or may be obtained by other reactions. It may also have other bonds consisting of addition and condensation.

In synthesizing such an alkali-soluble resin having an alkali-soluble group and an imide ring, a known and commonly used organic solvent can be used. As such an organic solvent, there is no problem as long as it does not react with the carboxylic acid anhydrides, amines, and isocyanates that are raw materials and dissolves these raw materials, and its structure is not particularly limited. In particular, aprotic solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, and γ-butyrolactone are preferred because of their high solubility of raw materials.

The alkali-soluble resin having at least one alkali-soluble group and an imide ring among phenolic hydroxyl groups and carboxyl groups as described above has an acid value of 20 to 200 mgKOH/g in order to be compatible with the photolithography process. and more preferably 60 to 150 mgKOH/g. When the acid value is 20 mgKOH/g or more, the solubility in alkali increases, the developability becomes good, and the degree of crosslinking with the thermosetting resin after light irradiation increases, so that sufficient development contrast can be obtained. Obtainable. Moreover, when the acid value is 200 mgKOH/g or less, so-called heat fogging can be suppressed particularly in the PEB process after light irradiation, which will be described later, and the process margin is increased.

In addition, the molecular weight of this alkali-soluble resin is preferably a mass average molecular weight of 1,000 to 100,000 in consideration of developability and cured coating film properties.

(Photoinitiator)
As the photopolymerization initiator used in the resin composition (b) of the resin layer (B), known and commonly used photopolymerization initiators can be used, such as benzoin compounds, acylphosphine oxide compounds, acetophenone compounds, α-aminoacetophenone compounds, oxime ester compounds, thioxanthone compounds, and the like.
In particular, when used in the PEB step after light irradiation, which will be described later, a photopolymerization initiator that also functions as a photobase generator is suitable. In this PEB step, a photopolymerization initiator and a photobase generator may be used together.
The amount of the photopolymerization initiator compounded is preferably 0.5 to 30 parts by mass with respect to 100 parts by mass of the alkali-soluble resin. When the amount is 0.5 parts by mass or more, the surface curability is improved, and when the amount is 30 parts by mass or less, halation is less likely to occur and good resolution is obtained. More preferably, it is 1.0 to 20 parts by mass.

(Photobase generator)
The photobase generator, which also functions as a photopolymerization initiator, undergoes a polymerization reaction of the heat-reactive compound described below by changing its molecular structure or by cleaving the molecule upon irradiation with light such as ultraviolet light or visible light. A compound that produces one or more basic substances that can function as a catalyst. Examples of basic substances include secondary amines and tertiary amines.

Examples of such photobase generators also functioning as photopolymerization initiators include α-aminoacetophenone compounds, oxime ester compounds, acyloxyimino groups, N-formylated aromatic amino groups, N-acylated aromatic and compounds having substituents such as group amino groups, nitrobenzylcarbamate groups, alkoxybenzylcarbamate groups, and the like. Among them, oxime ester compounds and α-aminoacetophenone compounds are preferred, and oxime ester compounds are more preferred. As α-aminoacetophenone compounds, those having two or more nitrogen atoms are particularly preferred.

Any α-aminoacetophenone compound may be used as long as it has a benzoin ether bond in the molecule and undergoes intramolecular cleavage when exposed to light to generate a basic substance (amine) that acts as a curing catalyst.

Any compound can be used as the oxime ester compound as long as it is a compound that generates a basic substance upon irradiation with light.

Such photobase generators may be used singly or in combination of two or more. The amount of the photobase generator compounded in the resin composition is preferably 1.0 to 40 parts by mass, more preferably 1.0 to 20 parts by mass, per 100 parts by mass of the alkali-soluble resin. When the amount is 1.0 parts by mass or more, a good contrast of the development resistance between the light-irradiated area and the non-irradiated area can be obtained. Moreover, when it is 40 parts by mass or less, the properties of the cured product are improved.

(Thermosetting resin)
The thermosetting resin contained in the resin composition (b) of the resin layer (B) is, like the thermosetting resin of the resin layer (A) described above, an epoxy resin, an oxetane compound, and two or more in the molecule. compounds having a thioether group, that is, episulfide resins, melamine resins, benzoguanamine resins, melamine derivatives, amino resins such as benzoguanamine derivatives, blocked isocyanate compounds, cyclocarbonate compounds, bismaleimides, carbodiimides, etc., can be used in combination. may

The thermosetting resin contained in the resin composition (b) of the resin layer (B) may be the same thermosetting resin as the thermosetting resin contained in the resin composition (a) of the resin layer (A). , may be different thermosetting resins. Moreover, a thermosetting resin can be used individually by 1 type or in combination of 2 or more types.

The blending ratio of the thermosetting resin is preferably 10 to 50% by mass, more preferably 15 to 45% by mass, more preferably 20 to 40% by mass, based on the total amount of the composition in terms of solid content. is more preferred.
As will be described later, it is preferable to appropriately adjust the equivalent ratio with the carboxyl group-containing resin.

The resin composition used in the resin layer (A) and the resin layer (B) as described above may optionally contain the following components.

(coloring agent)
A coloring agent can be added for the purpose of adjusting sensitivity. As the colorant, known and commonly used colorants such as red, blue, green, yellow, white, and black can be blended, and any of pigments, dyes, and pigments can be used.

(Other ingredients)
For the purpose of adjusting the sensitivity and improving the properties of the effect paint, known and commonly used additives such as antioxidants, ultraviolet absorbers, finely divided silica, hydrotalcite and silane coupling agents can be added.

[Laminated structure]
In the laminated structure of the present invention, the mixture of the alkali-soluble resin and the thermosetting resin contained in the resin composition (b) of the resin layer (B) has a gelation time at 150 ° C. of 120 seconds or more and 600 seconds or less, more preferably 180 seconds or more and 300 seconds or less, and the mixture of the carboxyl group-containing resin and the thermosetting resin contained in the resin layer (A) has a gelling time of 300 seconds at 150°C. It is characterized by being 1200 seconds or less, more preferably 360 seconds or more and 600 seconds or less, and longer than the gelling time of the mixture of the resin layer (B).
The lower limit of the result of measuring the thermal reactivity between the carboxyl group-containing resin and the thermosetting resin in the resin composition (a) of the resin layer (A) by gelation time is relatively long at 300 seconds or more, and the resin layer (B The lower limit of the result of measuring the thermal reactivity in the mixture of the alkali-soluble resin and the thermosetting resin contained in the resin composition (b) of ) by gelation time is 120 seconds or more, and the resin composition of the resin layer (A) By making a laminated structure of a combination relatively shorter than the lower limit of the result of measuring the thermal reactivity in the mixture of the carboxyl group-containing resin and the thermosetting resin contained in the product (a) by the gelation time, In the baking process, the reaction in the unexposed areas does not proceed and the product can have a long life. As a result, finer resolution can be obtained, and a cured product without residue can be obtained after development.
The method for measuring the gelling time is based on the gelling time measuring method described below.

In the laminated structure of the present invention, the resin layer (A) and the resin layer (B) are each made of a photocurable resin composition. Since the photocurable resin composition requires a heating step after exposure with a photobase generator, the gelation time of each composition is 60 to 1 in order to suppress the influence of the thermal reaction even in the unexposed area. , 200 seconds. In particular, the resin layer (B), in terms of developability and resistance to development after exposure and PEB, and properties of the cured coating film, has an alkali-soluble resin contained in the resin composition (b) of the resin layer (B) and the heat The gelling time of the mixture with the curable resin is preferably 120 to 600 seconds, more preferably 180 seconds or more and 300 seconds or less.
The resin layer (A) is made of a mixture of a carboxyl group-containing resin and each thermosetting resin contained in the resin composition (a) of the resin layer (A) in terms of developability, development residue and cured coating film properties. The gelation time is preferably 300 to 1,200 seconds, more preferably 360 seconds or more and 600 seconds or less.
Further, it is preferable that the gelation time of the resin composition of the resin layer (A) is longer than the gelation time of the resin composition of the resin layer (B), and the difference therebetween is 120 seconds or more.
The gelation time of the present invention is an index for combining resin components by adjusting parameters such as the acid value of each component, the molecular weight, the number of functional groups of the thermosetting resin, and the blending amount of the thermosetting resin, as shown below. It is as

(acid number)
The carboxyl group-containing resin and the alkali-soluble resin contained in the resin compositions of the resin layer (A) and the resin layer (B) of the present invention, respectively, have an acid value of 20 to 200 mgKOH/g in order to be compatible with the photolithography process. more preferably 30 to 100 mgKOH/g for the resin layer (A), and more preferably 30 to 150 mgKOH/g for the resin layer (B). When the acid value is 20 mgKOH/g or more, the solubility in alkali is increased, the developability is improved, and the degree of crosslinking with the thermosetting component after light irradiation is increased, so that sufficient development contrast is obtained. Obtainable. On the other hand, when the acid value is 200 mgKOH/g or less, accurate pattern drawing is facilitated, and in particular, so-called heat fogging in the PEB (POST EXPOSURE BAKE) step after light irradiation, which will be described later, can be suppressed, resulting in a large process margin. Become. Furthermore, in the present invention, the gelling time can be controlled by adjusting the acid value of the carboxyl group-containing resin of the resin composition of the resin layer (A) and the resin layer (B).
In particular, when the gelling time is controlled by the acid value of the carboxyl group-containing resin of the resin layer (A), the acid value is relatively low in the above range of 20 to 200 mgKOH/g, that is, the acid value is 20. Using a carboxyl group-containing resin of less than ~100 mgKOH/g can make the gelation time longer, and using a carboxyl group-containing resin with a relatively high acid value, that is, an acid value of 100 to 200 mgKOH/g Gelation time can be made shorter.

(Carboxyl group-containing resin, weight average molecular weight (Mw) of alkali-soluble resin)
The weight-average molecular weights of the carboxyl group-containing resin and the alkali-soluble resin contained in the resin compositions of the resin layer (A) and the resin layer (B), respectively, are A weight average molecular weight of 1,000 to 100,000 is preferred. Within this range, if the gelation time is controlled by the molecular weight of the resin, a relatively low molecular weight, that is, a carboxyl group-containing resin having a weight average molecular weight of 1,000 to 5,000, or an alkali-soluble resin will gel. The gelling time can be lengthened, and the gelation time can be shortened by using a carboxyl group-containing resin or alkali-soluble resin having a relatively high molecular weight, ie, a weight average molecular weight of more than 5,000 to 10,000.
In the present invention, the weight average molecular weight of the alkali-soluble resin of the resin layer (B) is preferably 5,000 to 100,000, more preferably 10,000 to 50,000, in order to adjust the gelation time. The weight average molecular weight of the carboxyl group-containing resin of the resin layer (A) is preferably 1,000 to 10,000, more preferably 2,000 to 5,000.

(Number of functional groups of thermosetting resin)
The thermosetting resin contained in the resin composition of the resin layer (A) and the resin layer (B) has a functional group capable of undergoing an addition reaction with a carboxyl group or a phenolic hydroxyl group by heat. As the thermosetting resin, for example, compounds having a cyclic (thio)ether group are preferable, and examples thereof include epoxy resins. The epoxy resin is a resin having an epoxy group, and any known epoxy resin can be used. When controlling the gelation time with a thermosetting resin, the gelation time can be lengthened by using a component with a functional group number of 2 or less, and the gelation time can be lengthened by using a component with a functional group number of 3 or more. can be made shorter.
In order to adjust the gelling time in the present invention, the resin layer (B) is preferably a polyfunctional epoxy resin having 3 or more epoxy groups in the molecule, and the resin layer (A) preferably has epoxy groups in the molecule. A bifunctional epoxy resin having two or less is preferable.

(Amount of thermosetting resin compounded)
The thermosetting resin contained in the resin composition of the resin layer (A) and the resin layer (B) has a functional group capable of undergoing an addition reaction with a carboxyl group or a phenolic hydroxyl group by heat.
As the amount of the thermosetting resin, the equivalent ratio of the carboxyl group-containing resin and the alkali-soluble resin contained in the resin composition of the resin layer (A) and the resin layer (B) (carboxyl group: thermal reactivity such as epoxy group group) is preferably 1.0:0.1 to 1.0:10.0. When controlling the gelation time with a thermosetting resin, the gelation time can be shortened as the equivalent ratio to the carboxyl group-containing resin increases.
In order to adjust the gelation time in the present invention, the equivalent ratio of the resin layer (B) is preferably 1.0:1.0 to 1.0:10.0, and the equivalent ratio of the resin layer (A) is 1.0:0.1 to 1.0:5.0 is preferred. More preferably, the resin layer (B) has a ratio of 1.0:1.2 to 1.0:5.0, and the resin layer (A) has a ratio of 1.0:0.5 to 1.0:2.5. preferable.

In the laminated structure, the thickness of the resin layer (B) is 2 μm or more and not more than half the thickness of the resin layer (A), and the thickness of the resin layer (A) is 10 to 80 μm. Preferred, more preferably 10-60.

The laminated structure may be formed by forming the resin composition of the resin layer (A) and the resin composition of the resin layer (B) into a dry film on a substrate such as a wiring board, or by sequentially forming liquid ones. It may be formed by coating. When used as a liquid, it may be one-liquid or two-liquid or more, but from the viewpoint of storage stability, it is preferably two-liquid or more.

[Dry film]
Next, the dry film of the present invention has a resin layer obtained by coating and drying the resin composition for the resin layer (A) and the resin composition for the resin layer (B) on the first film. When forming a dry film, first, the resin composition of the resin layer (A) and the resin composition of the resin layer (B) are diluted with the above organic solvent to adjust the viscosity to an appropriate value, and then a comma coater, A blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, or the like is used to coat the first film to a uniform thickness. After that, the applied composition is usually dried at a temperature of 40 to 130° C. for 1 to 30 minutes to form a resin layer. The thickness of the coating is not particularly limited, but is generally selected appropriately within the range of 5 to 150 μm, preferably 15 to 60 μm, in terms of thickness after drying.

A plastic film is used as the first film, and for example, a polyester film such as polyethylene terephthalate (PET), a polyimide film, a polyamideimide film, a polypropylene film, a polystyrene film, or the like can be used. The thickness of the first film is not particularly limited, but is generally selected appropriately within the range of 10 to 150 μm. More preferably, it is in the range of 15 to 130 μm.

After forming a resin layer composed of the resin composition of the resin layer (A) and the resin composition of the resin layer (B) on the first film, for the purpose of preventing dust from adhering to the surface of the film, Furthermore, it is preferable to laminate a peelable second film on the surface of the membrane. As the peelable second film, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, surface-treated paper, or the like can be used. As the second film, any film may be used as long as it has an adhesive strength smaller than that between the resin layer and the first film when the second film is peeled off.

In the present invention, the resin composition of the resin layer (B) and the resin composition of the resin layer (A) are coated on the second film and dried to form a laminated individual structure. A first film may be laminated on the surface. That is, the film to which the resin composition of the resin layer (A) and the resin composition of the resin layer (B) are applied when producing the dry film in the present invention may be either the first film or the second film. may be used.

The resin composition of the resin layer (A) and the resin composition of the resin layer (B) are, for example, adjusted to a viscosity suitable for the coating method using the above organic solvent, and then coated on the substrate by a dip coating method, a flow After applying by a method such as coating method, roll coating method, bar coating method, screen printing method, curtain coating method, etc., the organic solvent contained in the composition is volatilized and dried (temporary drying) at a temperature of 60 to 100 ° C. , a tack-free resin layer can be formed. In the case of a dry film obtained by coating the above composition on the first film or the second film, drying the composition, and winding it as a film, a laminator or the like is used so that the layer of the composition of the present invention comes into contact with the substrate. A resin layer can be formed by peeling off the first film after pasting on the base material.

Examples of the substrate include printed wiring boards and flexible printed wiring boards on which circuits are formed in advance using copper or the like, paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth/non-woven cloth epoxy, glass cloth/paper epoxy. , Synthetic fiber epoxy, fluororesin, polyethylene, polyphenylene ether, polyphenylene oxide, cyanate, and other materials such as copper-clad laminates for high-frequency circuits, and copper-clad laminates of all grades (FR-4, etc.) Plates, metal substrates, polyimide films, PET films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer plates and the like can also be used.

Volatilization drying performed after applying the resin composition to the substrate or the first film of the dry film can be performed using a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, etc. A method in which the hot air in the dryer is brought into countercurrent contact with the hot air in the dryer, and a method in which the support is blown from a nozzle) can be used.

[Cured product]
The dry film is formed on a substrate for electronic parts, such as a printed wiring board, by peeling off the first film, and is cured by exposure and alkali development. After alkali development, post-curing is performed as necessary. Without using a dry film, the resin composition (a) of the resin layer (A) and the resin composition (b) of the resin layer (B) are formed by coating on a substrate, followed by exposure and alkali development to obtain a cured product. be. After alkali development, post-curing is performed as necessary.

(Exposure (light irradiation) process)
In this step, the photobase generator contained in the resin layer (B) is activated in a negative pattern by irradiation with active energy rays, and the exposed portion is cured. In the case of the composition using the PEB process, which will be described later, a photopolymerization initiator or photobase generator functioning as a photobase generator is activated in a negative pattern to generate a base.
The exposure machine used in this process includes a direct drawing machine, an exposure machine equipped with a metal halide lamp, a light irradiation machine equipped with a (ultra) high pressure mercury lamp, a light irradiation machine equipped with a mercury short arc lamp, or a (ultra) A direct drawing apparatus using an ultraviolet lamp such as a high-pressure mercury lamp can be used. A mask for patternwise exposure is a negative mask.
As active energy rays used for exposure, laser light or scattered light having a maximum wavelength in the range of 350 to 450 nm is preferably used. By setting the maximum wavelength within this range, the photobase generator can be efficiently activated. Although the amount of exposure differs depending on the film thickness, etc., it is usually 100 to 1500 mJ/cm ² .
The resin composition (a) of the laminated resin layer (A) and the resin composition (b) of the resin layer (B) are exposed (light irradiation) to form an exposed portion (light irradiated portion). hardens. In this step, the light-irradiated portion is cured by activating the photobase generator contained in the resin layer by light irradiation in a negative pattern. In this step, the base generated in the light irradiation step can sufficiently cure deep portions of the resin layer. The heating temperature is, for example, 80-140.degree. The heating time is, for example, 2 to 140 minutes. Curing of the resin composition in the present invention is, for example, a ring-opening reaction of an epoxy resin due to a thermal reaction, so distortion and curing shrinkage can be suppressed compared to the case where curing proceeds by a photoradical reaction.

(PEB process)
In this step, the exposed portion is cured by heating the resin layer after exposure (light irradiation). In this step, the photobase generator is destabilized by the base generated in the light-irradiated portion, and the base chemically proliferates, so that the deep part of the resin layer can be fully cured. The heating temperature is, for example, 80-140.degree. The heating time is, for example, 2 to 140 minutes. Curing of the resin composition in the present invention is, for example, a ring-opening reaction of an epoxy resin due to a thermal reaction, so distortion and curing shrinkage can be suppressed compared to the case where curing proceeds by a photoradical reaction.

(Development process)
In the developing step, the non-irradiated portion is removed by alkali development to form a negative patterned insulating film. The developing method can be a dipping method, a shower method, a spray method, a brush method, or the like. Aqueous alkaline solutions such as amines can be used.

(Post-cure process)
In this step, after the developing step, the resin layer is completely heat-cured to obtain a highly reliable coating film. The heating temperature is, for example, 140.degree. C. to 180.degree. The heating time is, for example, 20 to 120 minutes. Furthermore, light irradiation may be performed before or after post-curing.

[Electronic parts]
The laminate structure of the present invention is preferably used for forming a cured film on a printed wiring board, more preferably for forming a permanent film, and more preferably for a semiconductor package or the like. , solder resists, interlayer dielectric layers, and coverlays. Further, according to the curable resin composition of the present invention, it is possible to obtain a cured product having excellent crack resistance. It can be suitably used for forming a permanent coating film such as a solder resist used for.

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

(Synthesis of alkali-soluble resin 1)
6.98 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane (hereinafter referred to as "BAPP"), 3, 3.80 g of 5-diaminobenzoic acid, 8.21 g of Jeffamine XTJ-542 (manufactured by Huntsman, molecular weight: 1025.64), and 86.49 g of γ-butyrolactone were charged and dissolved at room temperature.

Next, 17.84 g of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride and 2.88 g of trimellitic anhydride were charged and kept at room temperature for 30 minutes. Further, 30 g of toluene was charged, the temperature was raised to 160° C., and after removing the water generated together with the toluene, the mixture was held for 3 hours and cooled to room temperature to obtain an imidized compound solution.

9.61 g of trimellitic anhydride and 17.45 g of trimethylhexamethylene diisocyanate were added to the obtained imidized product solution and kept at a temperature of 160° C. for 32 hours. Thus, a polyamide-imide resin solution containing carboxyl groups was obtained (hereinafter abbreviated as A-1). The solid content was 40.1%, the solid content acid value was 83.1 mgKOH/g, and Mw was 4,500.

(Synthesis of alkali-soluble resin 2)
12.5 g of 3,5-diaminobenzoic acid and 2,2′-bis[4-(4-aminophenoxy) were placed in a separable three-necked flask equipped with a stirrer, a nitrogen inlet tube, a fractionating ring and a cooling ring. 8.2 g of phenyl]propane, 30 g of NMP, 30 g of γ-butyrolactone, 27.9 g of 4,4′-oxydiphthalic anhydride, and 3.8 g of trimellitic anhydride were added, and the mixture was stirred at room temperature and 100 rpm under a nitrogen atmosphere. and stirred for 4 hours. Next, 20 g of toluene was added, and the mixture was stirred for 4 hours at a silicon bath temperature of 180° C. and 150 rpm while toluene and water were distilled off to obtain an imide ring-containing alkali-soluble resin solution (hereinafter abbreviated as A-2). . After that, γ-butyrolactone was added so that the solid content was 30% by mass. The resulting resin solution had a solid content acid value of 86 mgKOH/g and an Mw of 10,000.

(Synthesis of carboxyl group-containing resin)
456 parts of bisphenol A, 228 parts of water and 649 parts of formalin were charged, 228 parts of an aqueous sodium hydroxide solution was added, reacted for 10 hours, neutralized to pH 4 with an aqueous phosphoric acid solution, and the aqueous layer was separated. Thereafter, methyl isobutyl ketone was added and dissolved uniformly, and the obtained polymethylol compound was dissolved in 550 parts of methanol to obtain a polymethylol compound. 500 parts of the methanol solution of the obtained polymethylol compound and 440 parts of 2,6-xylenol were charged, and then 8 parts of oxalic acid was added to obtain 550 parts of novolak resin A. Further, 130 parts of this novolac resin A, 2.6 parts of a 50% aqueous sodium hydroxide solution, and 100 parts of toluene/methyl isobutyl ketone (mass ratio = 2/1) were charged in an autoclave and heated to 45 parts of ethylene oxide. was gradually introduced and allowed to react. 3.3 parts of a 36% hydrochloric acid aqueous solution was added to this reaction solution and mixed, and the product neutralized with sodium hydroxide had a hydroxyl value of 175 g/eq. An ethylene oxide adduct of novolak resin A was obtained.
175 parts of the ethylene oxide adduct of novolak resin A thus obtained, 50 parts of acrylic acid, 3.0 parts of p-toluenesulfonic acid, 0.1 part of hydroquinone monomethyl ether and 130 parts of toluene were stirred and heated to 115°C. The reaction solution obtained by raising the temperature and reacting for 4 hours was washed with water using a 5% NaCl aqueous solution, and diethylene glycol monoethyl ether acetate was added to obtain an acrylate resin solution having a solid content of 68%.
Next, 312 parts of the obtained acrylate resin solution, 0.1 part of hydroquinone monomethyl ether, and 0.3 parts of triphenylphosphine are charged, the mixture is heated to 110° C., 45 parts of tetrahydrophthalic anhydride is added, and the mixture is stirred for 4 hours. After reacting and cooling, a carboxyl group-containing resin solution having a solid content of 70%, a solid content acid value of 65 mgKOH/g, and an Mw of 10,000 was obtained (hereinafter abbreviated as B-1).

The materials of each example and each comparative example shown in Table 1 were blended in the amounts shown in the table, premixed with a stirrer, and then kneaded with a three-roll mill to form a resin layer (A) and a resin layer. A resin composition (B) was prepared. Unless otherwise specified, the values in the table are parts by mass of the solid content.

<Formation of resin layer (A)>
A base material having a copper thickness of 18 μm formed on the entire surface was prepared, and pretreatment was performed using CZ8108B from MEC. After that, each resin composition of Examples and Comparative Examples was applied to the pretreated substrate by a method such as screen printing so that the film thickness after drying would be the thickness (unit: μm) shown in Table 1. coated on the substrate. Thereafter, the resin layer (A) was formed by drying at 90° C./30 minutes in a hot air circulating drying oven.

<Formation of resin layer (B)>
On the resin layer (A) formed as described above, each resin composition of Examples and Comparative Examples is applied by a method such as screen printing, and the film thickness after drying is shown in Table 1 (unit: μm). was applied so as to be Then, it was dried in a hot air circulation drying oven at 90° C./30 minutes to form a resin layer (B).

In this manner, laminated structures composed of the respective resin compositions of Examples and Comparative Examples were produced on the base material on which the copper thickness of 18 μm was formed over the entire surface.
In the case of the dry film lamination method, first, each resin composition of Examples and Comparative Examples was diluted with an organic solvent to adjust the viscosity to an appropriate value, and the first film was coated in the same manner as described above. Each resin composition of Examples was applied and dried to form a resin layer (B), and a resin layer (A) was applied and dried thereon to form a dry film having a resin layer. Next, the first film (PET film, thickness 25 μm) was peeled off after laminating so that the resin layer (A) side was in contact with the base material using a laminator or the like.

<Method for measuring gelation time>
Gelation time was measured using a hot plate type gelation tester (GT-D; manufactured by Eucalyptus Giken Co., Ltd.) in accordance with the hot plate method specified in JIS-C2161:2010.
The gelation time is measured from a mixture of the carboxyl group-containing resin of the resin layer (A) and each thermosetting resin, and a mixture of the alkali-soluble resin and the thermosetting resin of the resin layer (B). , each using a 1.00 mL syringe, to obtain 0.20 mL and place on the hot plate of the gelation tester set at 150° C., maintaining the stir needle at a 90 degree angle to the hot plate surface. While stirring, the sample was circularly stirred with a needle tip at a speed of 90±10 times/min. At this time, the end point was when the sample became gelatinous such that the stirring needle could not be rotated or the sample stopped sticking to the tip of the needle, and the time from placing the sample to the end point was measured. This operation was repeated three times, and the average time was taken as the gelation time. The gelling time of each mixture was as shown in Table 1.

<TCT crack resistance (thermal shock resistance)>
This test was conducted to evaluate crack resistance. The resin composition of each example and each comparative example was chemically treated (manufactured by MEC Co., Ltd., MEC Etch Bond CZ-8101, 1.0 μm etching), and then subjected to rust prevention treatment (manufactured by MEC Co., Ltd., MEC Etch Bond CL-8300). The entire surface is formed on a BT material (manufactured by Mitsubishi Gas Chemical Co., Ltd.), and an exposure process is performed with an exposure device (direct exposure device (DiIMPACT Mms60) manufactured by OAK Mfg. Co., Ltd.) at 200 mJ / cm ² with a 200 μm size open pattern, A PEB process was performed under the conditions of 90°C for 30 minutes, a development process (30°C, 0.2 MPa, 1 mass% Na ₂ CO ₃ aqueous solution for 60 seconds) was performed, and a post-curing process was evaluated under the conditions of 150°C for 60 minutes. A substrate was produced. After 1000 cycles of −65° C. (30 min.) + 175° C. (30 min.) using a thermal shock tester (manufactured by Etac Co., Ltd.), the obtained evaluation substrate was observed with an optical microscope to determine the opening (200 μm square). The presence or absence of crack generation was confirmed and evaluated according to the following criteria.
○: Crack incidence rate is less than 20% △: Crack incidence rate is 20% or more and less than 40% ×: Crack incidence rate is 40% or more

<Photopatternability>
A final test was conducted to evaluate the patterning properties. The resin composition of each example and each comparative example was chemically treated (manufactured by MEC Co., Ltd., MEC Etch Bond CZ-8101, 1.0 μm etching), and then subjected to rust prevention treatment (manufactured by MEC Co., Ltd., MEC Etch Bond CL-8300). The entire surface is formed on a copper-clad substrate, and an SRO pattern with a diameter of 40 μm to 200 μm is exposed at 200 mJ/cm ² with an exposure device (a direct exposure device (DiIMPACT Mms60) manufactured by ORC Manufacturing Co., Ltd.). , 90° C. for 30 minutes, followed by a development step (30° C., 0.2 MPa, 1% by mass Na ₂ CO ₃ aqueous solution for 60 seconds) to form an SRO pattern from Φ40 μm to Φ200 μm in increments of 10 μm. formed. In addition, the coating film was cured under the conditions of 150° C. for 60 minutes in a post-cure process, and the obtained evaluation substrate was observed using an optical microscope adjusted to 100 times, and the minimum size at which the opening was completely formed was evaluated. did.
◎: SRO size Φ50 μm or less ○: SRO size Φ50 to Φ60 μm △: SRO size Φ60 to Φ80 μm ×: SRO size Φ80 to Φ100 μm

<Development residue>
The laminated structure of each example and each comparative example was chemically treated (manufactured by MEC Co., Ltd., MEC Etch Bond CZ-8101, 1.0 μm etching), and then rust-proofed (manufactured by MEC Co., Ltd., MEC Etch Bond CL-8300). formed on a copper-clad substrate, subjected to pattern exposure at 200 mJ/cm ² with an exposure device (a direct exposure device (DiIMPACT Mms60) manufactured by Oak Manufacturing Co., Ltd.), and subjected to a PEB process at 90° C. for 30 minutes. Then, development (30° C., 0.2 MPa, 1 mass % Na ₂ CO ₃ aqueous solution for 60 seconds) was carried out, and residues in unexposed areas were visually evaluated.
〇: No residue ×: With residue

These evaluation results are also shown in Table 1.

The materials in Table 1 are as follows.
*1) Alkali-soluble resin 1 (A-1), Mw 4,500, whose synthesis method was explained earlier
*2) Alkali-soluble resin 2 (A-2), Mw 10,000, whose synthesis method was explained earlier
*3) Bifunctional epoxy resin (jER834, bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation), Mw470
*4) Polyfunctional epoxy resin (TEPIC-HP manufactured by Nissan Chemical Industries, Ltd.), Mw297
*5) IRGACURE OXE-02 (ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(0-acetyloxime), manufactured by BASF Japan)
*6) Acid-modified epoxy acrylate resin having a biphenyl novolak skeleton, (manufactured by Nippon Kayaku Co., Ltd., product number KAYARADZCR-1601H) solid content 65%, solid content acid value 98 mgKOH/g, Mw 4,500
*7) Carboxyl group-containing resin (B-1) solid content 70%, solid content acid value 65 mg KOH / g, Mw 10,000, whose synthesis method was explained above
*8) Acid-modified epoxy acrylate resin, KAYARAD ZFR-1401H (manufactured by Nippon Kayaku Co., Ltd., bisphenol F type epoxy acrylate resin), solid content 63%, solid content acid value 98 mgKOH / g, Mw 15,000
*9) Bifunctional epoxy resin, NC-3000L (biphenylaralkyl type epoxy resin, manufactured by Nippon Kayaku Co., Ltd.), Mw700
*10) Polyfunctional epoxy resin (EPICLON HP-4700 manufactured by DIC), Mw648
*11) Bifunctional tricyclodecanol methacrylate DCP (NK ester, manufactured by Shin-Nakamura Chemical Co., Ltd.)
*12) IRGACURE OXE-02 (ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(0-acetyloxime), manufactured by BASF Japan)

As is clear from the evaluation results shown in Table 1, the laminated structure of each example has excellent crack resistance and excellent resolution compared to the laminated structure of each comparative example. There was no development residue.

Claims

A laminated structure having two resin layers in which a resin layer (A) made of the resin composition (a) and a resin layer (B) made of the resin composition (b) are laminated,
The resin composition (b) of the resin layer (B) comprises an alkali-soluble resin, a photobase generator or a photopolymerization initiator and a photobase generator having the function of a photopolymerization initiator, a thermosetting resin, including
The resin composition (a) of the resin layer (A) contains a carboxyl group-containing resin and a thermosetting resin and does not substantially contain a photopolymerization initiator,
The mixture of the alkali-soluble resin and the thermosetting resin contained in the resin composition (b) of the resin layer (B) has a gelation time at 150° C. of 120 seconds or more and 600 seconds or less,
The mixture of the carboxyl group-containing resin and the thermosetting resin contained in the resin composition (a) of the resin layer (A) has a gelation time at 150° C. of 300 seconds or more and 1200 seconds or less, and A laminate structure, wherein the gelling time of the mixture contained in the resin composition (b) of the resin layer (B) is longer than the gelling time.
The laminate according to claim 1, wherein the thickness of the resin layer (B) is 2 µm or more and not more than half the thickness of the resin layer (A), and the thickness of the resin layer (A) is 10 to 80 µm. Structure.
A laminated structure according to claim 1 or 2, a film provided in contact with at least one surface of the surface of the resin layer (B) and the surface of the resin layer (A) of the laminated structure, A dry film comprising:
A cured product obtained by curing the resin layer of the laminated structure according to claim 1 or 2 or the dry film according to claim 3.
An electronic component comprising the cured product according to claim 4.