KR20230165789A - Laminated structures, dry films, cured products and electronic components - Google Patents

Abstract

A laminated structure is provided that not only achieves high levels of both conflicting characteristics such as B-HAST resistance and crack resistance, but also has excellent photo-patterning properties. A laminated structure having a two-layer resin layer in which a resin layer (A) containing a resin composition (a) and a resin layer (B) containing a resin composition (b) are laminated, and the resin of the resin layer (B) The composition (b) includes an alkali-soluble resin, a photobase generator having the function of a photopolymerization initiator, or a photopolymerization initiator and a photobase generator, and a thermosetting resin, and the resin composition (a) of the resin layer (A) is , a carboxyl group-containing resin, a thermosetting resin, and substantially no photopolymerization initiator, and formed after exposing the two-layer resin layer from the resin layer (B) side through a step tablet and performing a PEB process. It is characterized in that the difference between the gloss sensitivity and the residual sensitivity obtained by measuring the film thickness of the pattern and the film thickness of the pattern formed by development after the exposure and the PEB process is respectively 20 levels or less.

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, etc., and electronic components using them.

In recent years, in response to the increase in density of printed wiring boards accompanying the lighter, thinner, and shorter electronic devices, solder resists have also been required to have improved workability and high performance. In addition, in recent years, with the miniaturization, weight reduction, and performance improvement of electronic devices, miniaturization and multi-pin semiconductor packages have become practical, and mass production is in progress. Various semiconductor packages are being proposed in response to this increase in density.

In recent years, solder resists used in various semiconductor packages corresponding to higher densities have been required to have both high reliability in the use environment and high long-term reliability. One of the reliability tests regarding reliability in the use environment is the biased high acceleration stress test (Biased HAST, hereinafter referred to as B-HAST), and one of the long-term reliability tests is the crack resistance test in the heating and cooling cycle. B-HAST relates to a photocurable/thermocurable resin composition with excellent resistance, which is obtained by reacting a compound (a) having two or more phenolic hydroxyl groups per molecule with an alkylene oxide (b) or cyclocarbonate compound (c). There is a resin composition containing a carboxyl group-containing photosensitive resin obtained by reacting the obtained reaction product with an unsaturated group-containing monocarboxylic acid (d) and reacting the obtained reaction product with a polybasic acid anhydride (e) (Patent Document 1).

Japanese Patent No. 5183073 Publication

Since the resin composition described in Cited Document 1 contains a carboxyl group-containing photosensitive resin with a rigid skeleton, it is excellent in B-HAST resistance, but on the other hand, crack resistance in cold and heat cycles is necessarily sufficient at the level required in recent years. It wasn't.

When a resin composition containing a resin having a more flexible skeleton, such as a carboxyl group-containing urethane resin, is used instead of the carboxyl group-containing photosensitive resin having a rigid skeleton described above, crack resistance is improved, but B-HAST resistance tends to decrease. there was.

Therefore, the purpose of the present invention is to provide a laminated structure, dry film, cured product, and electronic components that not only can achieve high levels of both conflicting characteristics such as B-HAST resistance and crack resistance, but also have excellent photo-patterning properties. there is.

The present inventors conducted extensive research to solve the above problems and confirmed that by creating a laminate of two layers with different compositions, the conflicting characteristics of B-HAST resistance and crack resistance can be achieved at a high level. . Above all, in a laminated structure in which a layer suitable for B-HAST resistance and a layer suitable for crack resistance are simply laminated, it is difficult to control the sensitivity of each layer, so it has been found difficult to obtain good photo-patterning properties. In recent years, in the use of semiconductor packages, excellent photo-patterning properties that enable the opening diameter of the solder resist opening (SRO) to be 50 μm or less have been required.

Therefore, in order to obtain a laminated structure that has not only B-HAST resistance and crack resistance, but also excellent photo-patterning properties, further research and development were continued, and the present invention was completed.

That is, the laminated structure of the present invention is a laminated structure having a two-layer resin layer in which a resin layer (A) containing a resin composition (a) and a resin layer (B) containing a resin composition (b) are laminated. ,

The resin composition (b) of the resin layer (B) contains an alkali-soluble resin, a photobase generator having the function of a photopolymerization initiator or a photopolymerization initiator and a photobase 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 substantially does not contain a photopolymerization initiator,

After exposing the two resin layers from the resin layer (B) side through a step tablet and performing a PEB (POST EXPOSURE BAKE) process, the coating film thickness of the pattern formed, and after the exposure and performing the PEB process , It is characterized in that the difference between the gloss sensitivity and the residual sensitivity obtained by measuring the film thickness of the pattern formed by development is 20 levels or less. Additionally, details of the PEB process will be described later.

Here, the definitions of gloss sensitivity and residual sensitivity are as follows.

After exposing the two resin layers from the resin layer (B) side through a step tablet and performing the PEB process, assuming that the coating film thickness of the two resin layers before development of the formed pattern is 100%, After exposure, performing the PEB process, the largest value of the number of steps in which more than 95% of the film thickness remains after development is defined as gloss sensitivity, and when the film thickness before development is 100%, the film thickness after development is The largest value of the step number below 5% was defined as residual sensitivity.

In the present invention, the coating film thickness of the formed pattern was measured as the difference between the measured value obtained as the thickness of the entire coating film thickness and the measured value obtained as the thickness of the base material in accordance with JIS K 5600-1-7:2014. . The measurement method is a mechanical measurement method, using a thickness gauge (DIGIMICRO MF-501, manufactured by Nikon Corporation), exposing the two layers of resin layer to light from the resin layer (B) side through a step tablet, at 90°C for 30 minutes. After performing the PEB process, the coating film thickness of the formed pattern before development and the coating film thickness of the remaining coating film formed after the exposure, after performing the PEB process, and after development were measured, respectively, and the coating film before development was taken as 100%. When the largest value of the number of steps in which more than 95% of the film thickness remains after the development is referred to as gloss sensitivity, and when the film thickness before the development is 100%, the number of steps in which the film thickness is 5% or less after the development is The largest value of was called the residual sensitivity.

In the laminated structure of the present invention, the thickness of the resin layer (B) is 2 μm or more and less than half the thickness of the resin layer (A), and the thickness of the resin layer (A) is 10 to 80 μm. It is preferable, and 20 to 60 μm is more preferable.

In addition, the dry film of the present invention includes a film provided in contact with the laminated structure of the present invention and at least one of the surface of the resin layer (B) and the surface of the resin layer (A) of the laminated structure. It is characterized by:

Additionally, the cured product of the present invention is characterized in that it is obtained by curing the laminated structure of the present invention or the dry film laminated structure 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, it is possible to provide a laminated structure having not only B-HAST resistance and crack resistance but also excellent photo-patterning properties, a dry film, a cured product thereof, and electronic components using the cured product.

Hereinafter, embodiments of the laminated structure, dry film, cured product, and electronic component of the present invention will be described in detail.

(laminated structure)

The laminated structure of the present invention is a laminated structure having a two-layer resin layer in which a resin layer (A) containing a resin composition (a) and a resin layer (B) containing a resin composition (b) are laminated,

The resin composition (b) of the resin layer (B) contains an alkali-soluble resin, a photobase generator having the function of a photopolymerization initiator or a photopolymerization initiator and a photobase 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 substantially does not contain a photopolymerization initiator,

After exposing the two resin layers through a step tablet from the resin layer (B) side and performing the PEB process, the coating film thickness of the pattern formed, and the pattern formed by developing after the exposure and performing the PEB process The difference between the gloss sensitivity and the remaining sensitivity obtained by measuring each coating film thickness is 20 levels or less, and more preferably 14 levels or less.

When the laminated structure is formed on a substrate, the layer in contact with the substrate is the resin layer (A), and the layer in contact with the surface on the opposite side to the surface of the resin layer (A) on the side in contact with the substrate can be. This is stratum (B). That is, the laminated structure has a structure in which the resin layer (A) and the resin layer (B) are laminated in that order on a substrate. Examples of the substrate include printed wiring boards and flexible printed wiring boards in which circuits have been formed in advance using copper or the like.

The resin layer (B) contains a resin composition (b) containing an alkali-soluble resin, a photobase generator that also functions as a photopolymerization initiator, or a photopolymerization initiator and a photobase generator, and a thermosetting resin. The resin composition (b) of the resin layer (B) containing these components has photosensitivity because the photopolymerization initiator reacts with the alkali-soluble resin when irradiated with light, and also functions as a photobase generator of the polymerization initiator when heated. It is a photosensitive thermosetting resin composition that can be thermally cured.

The resin layer (A) contains a resin composition (a) that contains a carboxyl group-containing resin and a thermosetting resin and substantially does not contain a photopolymerization initiator. Substantially containing no photopolymerization initiator means that the photopolymerization initiator is less than 0.5 parts by mass per 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 since it is laminated in contact with the resin layer (B), this number Active species such as radicals generated from the photopolymerization initiator contained in the stratum (B) diffuse into the resin layer (A), so that the resin layer (A) also has photosensitivity. Additionally, it can be thermoset by heating. Therefore, in the laminated structure, it is possible to collectively form a predetermined pattern in the resin layer (B) and the resin layer (A) by development. In particular, when performing the PEB process after exposure, the effect of batch formation of patterns due to thermal diffusion at that time was significant.

[Resin layer (A)]

(Resin composition (a) of resin layer (A))

The resin layer (A) contains the resin composition (a). It is preferable 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 responding to the formation of various circuit patterns. Therefore, the resin composition (a) of the resin layer (A) uses a base generated from a base generator as a catalyst to cause an addition reaction between a resin having a carboxyl group, especially a carboxyl group-containing resin, and a thermosetting component by heating after exposure. It is preferable that it is a photosensitive thermosetting resin composition that allows development by removing the unexposed portion with an alkaline solution.

Specific examples of the carboxyl group-containing resin contained in the resin composition (a) of the resin layer (A) include the following compounds.

(1) Carboxyl group-containing resin obtained by copolymerization of an unsaturated carboxylic acid such as (meth)acrylic acid and an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth)acrylate, and isobutylene.

(2) Diisocyanates such as aliphatic diisocyanate, branched aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate, carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, and polycarbonate-based polyol and polyether-based polyol. , polyester polyol, polyolefin polyol, acrylic polyol, bisphenol A alkylene oxide adduct diol, carboxyl group-containing urethane resin by polyaddition reaction of diol compounds such as compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups. .

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

(4) Diisocyanate and bifunctional epoxy resins 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, and biphenol-type epoxy resin. A urethane resin containing a carboxyl group obtained by polyaddition reaction of (meth)acrylate or its partial acid anhydride modified product, a dialcohol compound containing a carboxyl group, 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 to form the terminal. (meth)acrylated urethane resin containing a carboxyl group.

(6) During the synthesis of the resin of (2) or (4) above, an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate, etc., has one isocyanate group and one or more (meth)acryloyl groups in the molecule. A urethane resin containing a carboxyl group whose ends have been (meth)acrylated by adding a compound.

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

(8) A carboxyl group-containing resin obtained by reacting (meth)acrylic acid with a polyfunctional epoxy resin in which the hydroxyl group of the difunctional epoxy resin is further epoxidized with epichlorohydrin, and dibasic acid anhydride is added to the hydroxyl group generated.

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

(10) The 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 is reacted with a monocarboxylic acid containing an unsaturated group, and a polybasic acid anhydride is added to the reaction product obtained. A carboxyl group-containing resin obtained by reaction.

(11) 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 is reacted with a monocarboxylic acid containing an unsaturated group, resulting in A carboxyl group-containing resin obtained by reacting a reaction product with a polybasic acid anhydride.

(12) Epoxy resins having multiple epoxy groups in one molecule, compounds having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule such as p-hydroxyphenethyl alcohol, and unsaturated compounds such as (meth)acrylic acid. A product obtained by reacting a group-containing monocarboxylic acid and reacting the alcoholic hydroxyl group of the obtained reaction product with a polybasic acid anhydride such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and adipic anhydride. Carboxyl group-containing resin.

(13) A carboxyl group-containing resin having at least either an amide structure or an imide structure.

(14) Maleimides or maleimide derivatives such as N-phenylmaleimide and N-benzylmaleimide, unsaturated carboxylic acids such as (meth)acrylic acid, and unsaturated groups having a hydroxyl group such as hydroxyalkyl (meth)acrylate. Glycidyl (meth)acrylate, α-methyl to a carboxyl group-containing copolymer resin containing a compound and an unsaturated group-containing compound having an aromatic ring such as styrene, α-methylstyrene, α-chlorostyrene, and vinyl toluene as monomers. Photosensitive carboxyl group-containing photosensitive carboxyl group having a copolymer structure, formed by adding a compound having one epoxy group and one or more (meth)acryloyl groups to a molecule such as glycidyl (meth)acrylate or epoxycyclohexylmethyl (meth)acrylate. profit.

(15) The carboxyl group-containing resins described in (1) to (13) above also contain one epoxy group and one or more ( A carboxyl group-containing resin obtained by adding a compound having a meta)acryloyl group.

In addition, in this specification, (meth)acrylate is a general term for acrylates, methacrylates, and mixtures thereof, and the same applies to other similar expressions.

The carboxyl group-containing resin contained in the resin composition (a) of the resin layer (A) can be used without being limited to those listed above. One type may be used individually, or multiple types may be mixed and used. Among the above carboxyl group-containing resins, they are ethylene oxide (EO) and propylene oxide (PO) modified resins starting from phenol resins (10) and ethylene carbonate and propylene carbonate modified resins starting from phenol resins (11), but they contain a photosensitive group. Since the unit with a carboxyl group and the developing unit with a carboxyl group are independent, even after the photosensitive unit is crosslinked by exposure, the developability of the developing unit with a carboxyl group is not affected, and a good contrast between the exposed and unexposed areas is obtained, making it easy to adjust the sensitivity. It is desirable because you can do it. In addition, the carboxyl group-containing resins (10) and (11) above may be used in combination with the carboxyl group-containing urethane resins (2) to (6) above.

The compounding amount of the carboxyl group-containing resin contained in the resin composition (a) of the resin layer (A) is 10 to 70% by mass in the total solid content of the resin composition (a). The coating film strength can be improved by setting it to 10% by mass or more. Additionally, by setting it to 70% by mass or less, the viscosity becomes appropriate and processability improves. In particular, in the present invention, in order to adjust the residual sensitivity, the carboxyl group-containing resin of the resin layer (A) is preferably 30 to 100% by mass, more preferably 70 to 100% by mass of the resins (10) and (11). It is 100% by mass. If it is within this range, it is possible to narrow the difference between gloss sensitivity and remaining sensitivity to 20 levels or less with a constant exposure amount.

In the present invention, from the viewpoint of adjusting the gloss sensitivity and residual sensitivity of the resin laminated structure, it is preferable that the resin composition (a) of the resin layer (A) does not substantially contain a photopolymerization initiator. Substantially containing no photopolymerization initiator means that the photopolymerization initiator is less than 0.5 parts by mass per 100 parts by mass of the carboxyl group-containing resin contained in the resin composition (a).

This is a photobase generator that functions as a photopolymerization initiator in the resin composition (b) of the resin layer (B) in order to collectively form a pattern by development in the laminated structure of the resin layer (B) and the resin layer (A). In that it contains, it is sufficient to cure the resin laminate. For example, if the resin composition (a) of the resin layer (A) contains a photopolymerization initiator, the residual sensitivity tends to increase, which adversely affects fine patterning.

[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 a curing reaction by heat. The thermosetting resin is not particularly limited and includes epoxy resins, oxetane compounds, compounds having two or more thioether groups in the molecule, that is, episulfide resins, melamine resins, benzoguanamine resins, melamine derivatives, benzoguanamine derivatives, etc. Amino resins, block isocyanate compounds, cyclocarbonate compounds, bismaleimide, carbodiimide, etc. can be used, and these may be used in combination.

The epoxy resin is a resin having an epoxy group, and all conventionally known ones can be used, and examples include a bifunctional epoxy resin having two epoxy groups in the molecule, and a polyfunctional epoxy resin having many epoxy groups in the molecule. Additionally, hydrogenated bifunctional epoxy resin may be used.

Examples of the epoxy resin 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, bisphenol A novolac type epoxy resin, biphenyl type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin, alicyclic epoxy resin, aliphatic Chain epoxy resin, phosphorus-containing epoxy resin, anthracene-type epoxy resin, norbornene-type epoxy resin, adamantane-type epoxy resin, fluorene-type epoxy resin, aminophenol-type epoxy resin, aminocresol-type epoxy resin, alkylphenol-type epoxy resin, etc. This is used. These epoxy resins can be used individually or in combination of two or more types.

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

As solid epoxy resins, naphthalene such as EPICLON HP-4700 (naphthalene type epoxy resin) manufactured by DIC, EXA4700 (tetrafunctional naphthalene type epoxy resin) manufactured by DIC, and NC-7000 (polyfunctional solid epoxy resin containing naphthalene skeleton) manufactured by Nippon Kayaku Corporation. type epoxy resin; Epoxidized products of condensates of phenols and aromatic aldehydes having phenolic hydroxyl groups, such as EPPN-502H (trisphenol epoxy resin) manufactured by Nippon Kayaku Co., Ltd. (trisphenol type epoxy resin); Dicyclopentadiene aralkyl type epoxy resins such as EPICLON HP-7200H (dicyclopentadiene skeleton-containing polyfunctional solid epoxy resin) manufactured by DIC; Biphenyl aralkyl type epoxy resins such as NC-3000H (polyfunctional solid epoxy resin containing biphenyl skeleton) manufactured by Nippon Kayaku Co., Ltd.; Biphenyl/phenol novolac type epoxy resins such as NC-3000L manufactured by Nippon Kayaku Co., Ltd.; Novolac-type epoxy resins such as EPICLON N660 and EPICLON N690 manufactured by DIC Corporation and EOCN-104S manufactured by Nippon Kayaku Corporation; Biphenyl type epoxy resins such as YX-4000 manufactured by Mitsubishi Chemical Corporation; Phosphorus-containing epoxy resins such as TX0712 manufactured by Nittetsu Chemical &Materials; Tris(2,3-epoxy propyl)isocyanurate such as TEPIC manufactured by Nissan Chemicals, etc. can be mentioned.

Semi-solid epoxy resins include EPICLON 860, EPICLON 900-IM, EPICLON EXA-4816, and EPICLON EXA-4822 manufactured by DIC, Epototo YD-134 manufactured by Nittetsu Chemical & Materials, jER834 and jER872 manufactured by Mitsubishi Chemical, and Sumitomo Chemical. Bisphenol A type epoxy resin such as ELA-134; Naphthalene type epoxy resins such as EPICLON HP-4032 manufactured by DIC Corporation; Phenol novolak-type epoxy resins such as EPICLON N-740 manufactured by DIC, etc. are included.

Liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, phenol novolak type epoxy resin, tert-butyl-catechol type epoxy resin, glycidyl amine type epoxy resin, and aminophenol type. Epoxy resin, alicyclic epoxy resin, etc. are mentioned.

Next, as oxetane compounds, 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)methylacryl ester, (3-ethyl-3-oxetanyl)methyl acrylate, (3-methyl-3-oxetanyl)methyl methacrylate, (3-ethyl-3-oxetanyl)methyl methacrylate or their In addition to polyfunctional oxetanes such as oligomers or copolymers, oxetane alcohol, novolak resin, poly(p-hydroxy styrene), cardo-type bisphenols, calixarenes, calixresorcin arenes, or silsesqui and ether compounds with resins having hydroxyl groups such as oxane. Other examples include copolymers of an unsaturated monomer having an oxetane ring and an alkyl (meth)acrylate.

Examples of the episulfide resin include bisphenol A episulfide resin. Furthermore, using the same synthesis method, an episulfide resin in which the oxygen atom of the epoxy group of the epoxy resin is replaced with a sulfur atom can also be used.

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

The molecular weight of the thermosetting resin contained in the resin composition (a) of the resin layer (A) is preferably a weight average molecular weight of 100 to 2,000 in order to adjust developability and cured film properties. Within this range, when adjusting the residual sensitivity based on the molecular weight of the thermosetting resin, the number of steps for the residual sensitivity can be reduced by using a low molecular weight component, that is, a component with a weight average molecular weight (Mw) of 100 to 1,000. That is, if a component with a weight average molecular weight of more than 1,000 to 2,000 is used, the number of steps in remaining sensitivity can be increased. In the examples of the present invention, the residual sensitivity is adjusted by using an epoxy resin with a weight average molecular weight of 1,000 or less so that the number of steps is not excessively large.

Thermosetting resins can be used individually or in combination of two or more types. The mixing ratio of the thermosetting resin is preferably 10 to 50% by mass, more preferably 15 to 45% by mass, and even more preferably 19 to 40% by mass, in terms of solid content, based on the total amount of the resin composition (a). desirable.

[Photopolymerizable monomer]

The resin composition (a) of the resin layer (A) is prepared by causing an addition reaction between a resin having a carboxyl group and a thermosetting component by heating after exposure, using a base generated from a base generator as a catalyst as described above, and forming the unexposed portion. It is a photosensitive thermosetting resin composition that can be developed by removing it with an alkaline solution. As a result, there is no need to mix the necessary (meth)acrylate monomer in the photosensitive resin composition using a polymerization reaction by radicals generated from a conventional photo radical polymerization initiator. Above all, a (meth)acrylate monomer may be blended in the resin composition of the resin layer (A), mainly to adjust the sensitivity of the resin layer (A). For example, it is possible to mix about 10 to 100 parts by mass of (meth)acrylate monomer with respect to 100 parts by mass of the carboxyl group-containing resin of the resin layer (A).

[Resin layer (B)]

(Resin composition (b) constituting the resin layer (B))

The resin layer (B) contains the 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) enables radical polymerization by light using a photopolymerization initiator, and uses a base generated from a base generator as a catalyst to heat the alkali-soluble resin and the thermosetting component after exposure to light. It is a photosensitive thermosetting resin composition that can be developed by carrying out an addition reaction and removing the unexposed portion with an alkaline solution.

The alkali-soluble resin contained in the resin composition (b) of the resin layer (B) includes, for example, 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, and includes known and commonly used resins. is used. In particular, carboxyl group-containing resin or carboxyl group-containing photosensitive resin that contains a compound having a carboxyl group and has been conventionally used as a solder resist composition can be mentioned. Here, as the carboxyl group-containing resin or 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 that is excellent in properties such as bending resistance and heat resistance can be suitably used.

The molecular weight of the carboxyl group-containing resin contained in the resin composition (b) of the resin layer (B) is preferably a weight average molecular weight of 1,000 to 10,000 in order to adjust fine patterning properties and surface hardening properties. Within this range, when controlling the gloss sensitivity by the molecular weight of the carboxyl group-containing resin component, the number of gloss sensitivity steps can be reduced by using a carboxyl group-containing resin with a low molecular weight, that is, 1,000 to 5,000, and with a high molecular weight, that is, exceeding 5,000. By using a carboxyl group-containing resin of 10,000 to 10,000, the number of gloss sensitivity steps can be increased. When the alkali-soluble resin having an imide ring described later has a carboxyl group, the gloss sensitivity can be similarly adjusted within the range of the weight average molecular weight mentioned above.

(Alkali-soluble resin having an imide ring)

In the present invention, the alkali-soluble resin having an imide ring has one or more alkali-soluble groups selected from a phenolic hydroxyl group and a carboxyl group and an imide ring. A known and commonly used method can be used to introduce the imide ring into this alkali-soluble resin. For example, a resin obtained by reacting a carboxylic acid anhydride component with an amine component and/or an isocyanate component can be mentioned. Imidization may be performed by thermal imidation, chemical imidation, or a combination of these.

Here, examples of the carboxylic acid anhydride component include tetracarboxylic acid anhydride and tricarboxylic acid anhydride, but are not limited to these acid anhydrides, and any compound having an acid anhydride group and a carboxyl group that reacts with an amino group or an isocyanate group can be used. , including its derivatives, can be used. In addition, these carboxylic acid anhydride components may be used individually or in combination.

As the amine component, diamines such as aliphatic diamine and aromatic diamine, polyhydric amines such as aliphatic polyetheramine, diamines having a carboxylic acid, diamines having a phenolic hydroxyl group, etc. can be used, but are not limited to these amines. In addition, these amine components may be used individually or in combination.

As the isocyanate component, diisocyanates such as aromatic diisocyanates and their isomers and multimers, aliphatic diisocyanates, alicyclic diisocyanates and their isomers, and other general-purpose diisocyanates can be used, but are not limited to these isocyanates. no. In addition, these isocyanate components may be used individually or in combination.

The alkali-soluble resin having an imide ring as described above may have an amide bond. This may be a polyamideimide obtained by reacting an imidide having a carboxyl group with an isocyanate and a carboxylic acid anhydride, or it may be obtained by a reaction other than that. Additionally, it may have other bonds including addition and condensation.

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

The alkali-soluble resin having an imide ring and at least one alkali-soluble group among the phenolic hydroxyl group and the carboxyl group as described above has an acid value of 20 to 200 mgKOH in order to adapt to the photolithography process and adjust the gloss sensitivity and residual sensitivity. It is preferably /g, and more preferably 60 to 150 mgKOH/g. When this acid value is 20 mgKOH/g or more, solubility in alkali increases, developability becomes good, and furthermore, the degree of crosslinking with the heat-curing component after light irradiation increases, so that sufficient development contrast can be obtained. In addition, when the acid value is 200 mgKOH/g or less, so-called thermal overheating in the PEB process after light irradiation, which will be described later, can be suppressed, and the process margin increases.

In addition, the molecular weight of this alkali-soluble resin is preferably 1,000 to 100,000, more preferably 2,000 to 50,000 in order to adjust developability and cured film properties. When this molecular weight is 1,000 or more, sufficient development resistance and cured properties can be obtained after exposure and PEB. Additionally, when the molecular weight is 100,000 or less, alkali solubility increases and developability improves.

(Photopolymerization initiator)

As the photopolymerization initiator used in the resin composition (b) of the resin layer (B), known and commonly used ones can be used, for example, benzoin compounds, acylphosphine oxide-based compounds, acetophenone-based compounds, and α-aminoaceto. Phenone compounds, oxime ester compounds, thioxanthone-based compounds, etc. can be mentioned. The resin composition (b) of the resin layer (B) contains a photopolymerization initiator, thereby enabling radical polymerization by light.

In particular, when used in the PEB process after light irradiation described later, a photopolymerization initiator that also functions as a photobase generator is suitable. Additionally, in this PEB process, a photopolymerization initiator and a photobase generator may be used together.

The amount of the photopolymerization initiator is preferably 0.5 to 30 parts by mass per 100 parts by mass of the alkali-soluble resin. When it is 0.5 parts by mass or more, surface hardenability becomes good, and when it is 30 parts by mass or less, halation is unlikely to occur and good resolution is obtained. More preferably, it is 1.0 to 20 parts by mass.

(Photobase generator)

A photobase generator that also functions as a photopolymerization initiator is one or more types of photobase generators that can function as a catalyst for the polymerization reaction of a heat-reactive compound described later by changing the molecular structure or cleavage of the molecule upon irradiation of light such as ultraviolet rays or visible light. It is a compound that produces basic substances. Examples of basic substances include secondary amines and tertiary amines.

Examples of photobase generators that also function as such photopolymerization initiators include α-aminoacetophenone compounds, oxime ester compounds, acyloxyimino groups, N-formylated aromatic amino groups, N-acylated aromatic amino groups, and nitrobenzylcarboxyl groups. Compounds having substituents such as a bamate group and an alkoxybenzyl carbamate group can be mentioned. Among them, oxime ester compounds and α-aminoacetophenone compounds are preferable, and oxime ester compounds are more preferable. As the α-aminoacetophenone compound, one having two or more nitrogen atoms is particularly preferable.

The α-aminoacetophenone compound may have a benzoin ether bond in the molecule, and when irradiated with light, cleavage occurs within the molecule to generate a basic substance (amine) that acts as a curing catalyst.

As an oxime ester compound, any compound that produces a basic substance by light irradiation can be used.

These photobase generators may be used individually, or may be used in combination of two or more types. The amount of the photobase generator 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. In the case of 1.0 parts by mass or more, good development resistance contrast of the light irradiated part/unirradiated part can be obtained. Additionally, when the amount is 40 parts by mass or less, the properties of the cured product improve.

(thermosetting resin)

The thermosetting resin (b) of the resin layer (B), like the thermosetting resin of the resin layer (A) described above, is an epoxy resin, an oxetane compound, a compound having two or more thioether groups in the molecule, that is, an episulfide resin, and a melamine. Resins, benzoguanamine resins, melamine derivatives, amino resins such as benzoguanamine derivatives, block isocyanate compounds, cyclocarbonate compounds, bismaleimide, carbodiimide, etc. can be used, and these may be used in combination.

The thermosetting resin (b) of the resin layer (B) may be the same thermosetting resin as the thermosetting resin of the resin layer (A), or may be a different thermosetting resin. In addition, thermosetting resins can be used individually or in combination of two or more types.

The mixing ratio of the thermosetting resin, in terms of solid content, is preferably 10 to 50% by mass, more preferably 15 to 45% by mass, and even more preferably 20 to 40% by mass, based on the total amount of the composition.

The following components can be blended as needed in the resin composition used in the resin layer (A) and resin layer (B) as described above.

(coloring agent)

For the purpose of adjusting sensitivity, a colorant can be added. As the colorant, known and commonly used colorants such as red, blue, green, yellow, white, and black can be mixed, and may be any of pigments, dyes, and pigments.

(Other Ingredients)

For the purpose of adjusting sensitivity or improving the properties of effect paints, known and commonly used additives such as antioxidants, ultraviolet absorbers, finely divided silica, hydrotalcite, silane coupling agents, etc. can be mixed.

[Layered structure]

The thickness of the resin layer (B) is 2 μm or more and less than half the thickness of the resin layer (A), and the thickness of the resin layer (A) is preferably 10 to 80 μm, more preferably 20 to 60 μm. desirable.

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

[Dry film]

Next, the dry film of the present invention has a resin layer obtained by applying and drying the resin composition (a) of the resin layer (A) and the resin composition (b) of the resin layer (B) on the first film. When forming a dry film, first, the resin composition (a) of the resin layer (A) and the resin composition (b) of the resin layer (B) are diluted with the above organic solvent to adjust the viscosity to an appropriate viscosity, and then used with a comma coater and blade. It is applied to a uniform thickness on the carrier film by a coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, etc. 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. There is no particular limitation on the coating film thickness, but generally, the film thickness after drying is appropriately selected from the range of 5 to 150 ㎛, preferably 15 to 60 ㎛.

As the first film, a plastic film is used, and for example, polyester films such as polyethylene terephthalate (PET), polyimide films, polyamideimide films, polypropylene films, polystyrene films, etc. can be used. There is no particular limitation on the thickness of the first film, but it is generally appropriately selected from the range of 10 to 150 μm. More preferably, it is in the range of 15 to 130㎛.

After forming the resin layer containing the resin composition (a) of the resin layer (A) and the resin composition (b) of the resin layer (B) on the first film, preventing dust from adhering to the surface of the film, etc. For this purpose, it is also desirable to laminate a peelable cover film on the surface of the membrane. As the peelable second film, for example, polyethylene film, polytetrafluoroethylene film, polypropylene film, surface-treated paper, etc. can be used. The second film may be one that is smaller than the adhesive force between the resin layer and the first film when peeling off the cover film.

Furthermore, in the present invention, a laminated structure is formed by applying and drying the resin composition (b) of the resin layer (B) and the resin composition (a) of the resin layer (A) on the second film, and forming a layered structure on the surface of the second film. The first film may be laminated. That is, in the present invention, when producing a dry film, the film to which the resin composition (a) of the resin layer (A) and the resin composition (b) of the resin layer (B) are applied is either the first film or the second film. You can also use

The resin composition of the resin layer (A) and the resin composition of the resin layer (B) are adjusted to a viscosity suitable for the application method using, for example, the above-mentioned organic solvent, and applied to the substrate by dip coating, flow coating, or roll. After application by a method such as a coating method, a bar coater method, a screen printing method, or a curtain coating method, the organic solvent contained in the composition is volatilized and dried (temporarily dried) at a temperature of 60 to 100° C., thereby forming a tack-free resin layer. can be formed. In addition, in the case of a dry film in which the composition is applied on a carrier film or cover film, dried, and wound as a film, the composition layer of the present invention is bonded to the substrate by a laminator or the like so that it contacts the substrate, and then the carrier film is peeled off. By doing so, a resin layer can be formed.

As the substrate, in addition to printed wiring boards and flexible printed wiring boards with circuits formed in advance of copper or the like, paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth/nonwoven epoxy, glass cloth/paper epoxy, synthetic fiber epoxy, and fluororesin. · Materials such as copper-clad laminates for high-frequency circuits using polyethylene, polyphenylene ether, polyphenylene oxide, cyanate, etc. are used, including copper-clad laminates of all grades (FR-4, etc.), metal substrates, and polyimide films. , PET film, polyethylene naphthalate (PEN) film, glass substrate, ceramic substrate, wafer plate, etc.

Volatilization drying performed after applying the resin composition to the base material or the first film of the dry film can be done using a hot air circulation type drying furnace, an IR furnace, a hot plate, a convection oven, etc. (using a heat source of an air heating type using steam). This can be done using a method of countercurrent contact with hot air in the dryer and a method of spraying it from a nozzle to a support. In addition, heating performed in the PEB process and post-curing process described later can be performed using the hot air circulation type drying furnace or the like.

[Hardened product]

The dry film is formed on a substrate for electronic components, such as a printed wiring board, by peeling off the first film, and becomes a cured product through 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 applied and formed on a substrate, followed by exposure and alkali development to obtain a cured product. After alkali development, post-curing is performed as necessary.

(Exposure (light irradiation) process)

In this step, the photobase generator contained in the resin composition (b) of the resin layer (B) is activated into a negative pattern by irradiation of active energy rays, and the exposed portion is cured. In the case of a composition using the PEB process described later, a photopolymerization initiator or a photobase generator that functions as a photobase generator is activated in a negative pattern to generate a base.

Exposure machines used in this process include direct drawing devices, exposure machines equipped with metal halide lamps, light irradiators equipped with (ultra) high-pressure mercury lamps, light irradiators equipped with mercury short arc lamps, or (ultra) high-pressure mercury lamps. A direct drawing device using an ultraviolet lamp can be used. The mask for exposure on a pattern is a negative mask.

As the active energy ray used for exposure, it is preferable to use laser light or scattered light with a maximum wavelength in the range of 350 to 450 nm. By setting the maximum wavelength within this range, the photobase generator can be activated efficiently. In addition, the exposure amount varies depending on the film thickness, etc., but can usually be 100 to 1500 mJ/cm2.

By performing exposure (light irradiation) on the resin composition (a) of the laminated resin layer (A) and the resin composition (b) of the resin layer (B), the exposed portion (light irradiated portion) is cured. In this process, a photobase generator contained in the resin layer is activated by irradiating light in a negative pattern to cure the light irradiated portion. In this process, the photobase generator is destabilized by the base generated in the light irradiation area, and the base chemically proliferates, allowing sufficient curing of the deep portion of the resin layer. The exposure machine used for light irradiation may be a device that irradiates ultraviolet rays in the range of 350 to 450 nm.

(PEB (POST EXPOSURE BAKE) process)

In this process, after exposure (light irradiation), the exposed portion is cured by heating the resin layer. In this process, the deep portion of the resin layer can be sufficiently cured by the base generated in the light irradiation process. The heating temperature is, for example, 80 to 140°C. The heating time is, for example, 2 to 140 minutes. Since curing of the resin composition in the present invention is, for example, a ring-opening reaction of an epoxy resin by a thermal reaction, deformation and curing shrinkage can be suppressed compared to the case where curing proceeds by a photo radical reaction.

(Development process)

In the development process, unradiated portions are removed through alkaline development to form an insulating film in a negative pattern. Developing methods can be dipping, showering, spraying, brushing, etc., and as a developing solution, alkaline aqueous solutions such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, and amines can be used. there is.

(Post curing process)

In this process, after the development process, the resin layer is completely heat-cured to obtain a highly reliable coating film. The heating temperature is, for example, 140°C to 180°C. The heating time is, for example, 20 to 120 minutes. Additionally, light irradiation may be performed before or after post-curing.

[Electronic parts]

The laminated structure of the present invention is suitably used for semiconductor packages, etc. to form a cured film on a printed wiring board, more suitably used to form a permanent film, and more suitably used as a solder resist and interlayer insulation. It is used to form layers and cover lays. In addition, according to the curable resin composition of the present invention, a cured product with excellent crack resistance can be obtained, so that it can be used on printed wiring boards, for example, package boards, with fine-pitch wiring patterns that are highly susceptible to defects due to crack generation. It can be suitably used for forming permanent coating films such as solder resist.

Example

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[Synthesis Example 1]

220 parts of cresol novolak-type epoxy resin (DIC Co., Ltd., EPICLON N-695, epoxy equivalent: 220) were placed in a four-necked flask equipped with a stirrer and reflux condenser, and 214 parts of carbitol acetate were added and heated and dissolved. Next, 0.1 part of hydroquinone as a polymerization inhibitor and 2.0 parts of dimethylbenzylamine as a reaction catalyst were added. This mixture was heated to 95 to 105°C, 72 parts of acrylic acid was added dropwise, and it was allowed to react for 16 hours. This reaction product was cooled to 80 to 90°C, 106 parts of tetrahydrophthalic anhydride was added, it was made to react for 8 hours, and it was taken out after cooling.

The photosensitive resin solution (A-1) having both an ethylenically unsaturated bond and a carboxyl group obtained in this way had a non-volatile content of 65%, a solid acid value of 100 mgKOH/g, and a weight average molecular weight (Mw) of about 3,500.

[Synthesis Example 2]

6.98 g of 2,2-bis[4-(4-aminophenoxy)phenyl]propane (hereinafter referred to as “BAPP”), 3,5- in a four-necked 300 mL flask equipped with a nitrogen gas introduction tube, thermometer, and stirrer. 3.80 g of diaminobenzoic acid, 8.21 g of Jeffamine XTJ-542 (manufactured by Huntsman, molecular weight 1025.64), and 86.49 g of γ-butyrolactone were added 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 added, and kept at room temperature for 30 minutes. Additionally, 30 g of toluene was added, the temperature was raised to 160°C, the water produced along with the toluene was removed, the mixture was maintained for 3 hours, and the imidide solution was obtained by cooling to room temperature.

9.61 g of trimellitic anhydride and 17.45 g of trimethylhexamethylene diisocyanate were added to the obtained imidate solution, and maintained at a temperature of 160°C for 32 hours. In this way, a polyamideimide resin solution (A-2) containing a carboxyl group was obtained. The solid content was 40.1%, the solid acid value was 83.1 mgKOH/g, and the weight average molecular weight (Mw) was 4,500.

[Synthesis Example 3]

In an autoclave equipped with a thermometer, a nitrogen introduction device and an alkylene oxide introduction device, and a stirring device, 119.4 g of novolak-type cresol resin (manufactured by Aika Kogyo Co., Ltd., brand name "Shonol CRG-951", OH equivalent weight: 119.4), hydroxyl. 1.19 g of potassium and 119.4 g of toluene were added, the inside of the system was replaced with nitrogen while stirring, and the temperature was raised by heating. Next, 63.8 g of propylene oxide was added dropwise little by little, and reacted at 125 to 132°C and 0 to 4.8 kg/cm2 for 16 hours. Afterwards, it was cooled to room temperature, and 1.56 g of 89% phosphoric acid was added to the reaction solution and mixed to neutralize potassium hydroxide, resulting in propylene oxide reaction of novolak-type cresol resin with a non-volatile content of 62.1% and a hydroxyl value of 182.2 g/eq. A solution was obtained. This was an average of 1.08 moles of alkylene oxide added per equivalent of phenolic hydroxyl group. Next, 293.0 g of the alkylene oxide reaction solution of the obtained novolak-type cresol resin, 43.2 g of acrylic acid, 11.53 g of methanesulfonic acid, 0.18 g of methyl hydroquinone, and 252.9 g of toluene were added to a reactor equipped with a stirrer, thermometer, and air intake tube. Then, air was blown in at a rate of 10 ml/min and the mixture was stirred while reacting at 110°C for 12 hours. The water produced by the reaction was an azeotropic mixture with toluene, and 12.6 g of water flowed out. After that, it was cooled to room temperature, and the obtained reaction solution was neutralized with 35.35 g of 15% aqueous sodium hydroxide solution and then washed with water. Thereafter, toluene was distilled off in an evaporator while being replaced with 118.1 g of diethylene glycol monoethyl ether acetate to obtain a novolak-type acrylate resin solution. Next, 332.5 g of the obtained novolak-type acrylate resin solution and 1.22 g of triphenylphosphine were introduced into a reactor equipped with a stirrer, a thermometer, and an air blowing tube, and air was blown in at a rate of 10 ml/min and stirred, 60.8 g of tetrahydrophthalic anhydride was added little by little, and reaction was performed at 95 to 101°C for 6 hours. In this way, a carboxyl group-containing photosensitive resin solution (A-3) with a solid acid value of 88 mgKOH/g, a solid content of 71%, and a weight average molecular weight (Mw) of 2,000 was obtained.

The materials of each example and each comparative example shown in Table 1 and Table 2 were mixed in the amounts shown in these tables, premixed with a stirrer, and then kneaded with a three-roll mill to obtain the resin composition of the resin layer (A) ( The resin composition (b) of a) and the resin layer (B) was prepared. In addition, the values in the table are parts by mass of solid content unless otherwise specified.

<Formation of resin layer (A)>

A substrate formed on the entire surface with a copper thickness of 18 µm was prepared, and pretreatment was performed using Mack CZ8108B. Thereafter, each resin composition of Examples and Comparative Examples was applied to the substrate subjected to the above pretreatment by a method such as screen printing so that the film thickness after drying was the thickness (unit: ㎛) in Tables 1 and 2. applied. After that, the resin layer (A) was formed by drying at 90°C for 30 minutes in a hot air circulation type drying furnace.

<Formation of resin layer (B)>

On the resin layer (A) formed as described above, each resin composition of Examples and Comparative Examples was applied by a method such as screen printing so that the film thickness after drying was the thickness (unit: ㎛) in Tables 1 and 2. applied. After that, it was dried at 90°C/30 minutes in a hot air circulation type drying furnace to form a resin layer (B).

In this way, a laminated structure containing each resin composition of the Examples and Comparative Examples was produced on the substrate whose entire surface was formed with the copper thickness of 18 μm.

In the case of the dry film lamination method, first, each resin composition of the examples and comparative examples was diluted with an organic solvent to adjust the viscosity to an appropriate viscosity, and then each resin composition of the examples and comparative examples was applied to the carrier film in the same manner as above. It was dried to form a resin layer (B), and a resin layer (A) was formed thereon to produce a dry film. Next, after bonding the resin layer (A) side into contact with the base material using a laminator or the like, the carrier film was peeled off.

<Sensitivity>

Each of the obtained laminated structures on the substrate was exposed using an exposure apparatus (HMW-680-GW20) equipped with a metal halide lamp through a 41-stage step tablet (T-4105 manufactured by STOUFFER), and subjected to PEB at 90°C for 30 minutes. After performing the process, developing at 30°C and 0.2MPa with a 1.0% sodium carbonate aqueous solution under development conditions tailored to each composition (see Table 1 and Table 2), the gloss sensitivity and residual sensitivity were determined from the pattern formed with a 41-stage step tablet. evaluated. The exposure amount was adjusted so that the gloss sensitivity was 10 levels.

Gloss sensitivity and residual sensitivity were measured as follows according to the above-mentioned definitions.

After exposing each laminated structure (two layers of resin layers) on the obtained substrate from the resin layer (B) side through a step tablet and performing a PEB process, the coating film thickness of the two layers of resin layers before development of the formed pattern When is 100%, the largest value of the number of steps in which a film thickness of 95% or more remains after the exposure, the PEB process, and development is referred to as gloss sensitivity, and the film thickness before development is taken as 100%. At this time, the largest value of the number of steps at which the film thickness becomes 5% or less after the development was referred to as the residual sensitivity.

Here, after exposing each laminated structure formed on the substrate and performing the PEB process, the coating film thickness before and after development of the formed pattern is based on JIS K 5600-1-7:2014, and is taken as the thickness of the entire coating film thickness. It was measured as the difference between the obtained measured value and the measured value obtained as the thickness of the base material.

The measurement method is a mechanical measurement method in which each laminated structure formed on the substrate is exposed from the resin layer (B) side through a step tablet using a thickness gauge (DIGIMICRO MF-501, manufactured by Nikon Corporation) at 90°C and 30°C. After performing the PEB process, the coating film thickness of the formed pattern before development and the coating film thickness of the remaining coating film formed after the exposure, after performing the PEB process, and after development were measured, respectively, and the coating film thickness before development was measured as 100%. In this case, the largest value of the number of steps in which more than 95% of the film thickness remains after the development is referred to as gloss sensitivity, and when the film thickness before the development is 100%, the film thickness after the development is 5% or less. The largest value of the number of steps was called the residual sensitivity.

<B-HAST resistance>

The above resin composition was formed on a comb-shaped evaluation substrate with L/S = 12/13 μm, an exposure process was performed under the conditions described above, a PEB process was performed at 90°C for 30 minutes, and then development (30°C, 0.2 MPa, 1% by mass Na2CO3 aqueous solution) process was performed to obtain a resist pattern. In addition, the post-curing process cured the coating film under the conditions of 150°C for 60 minutes. A bias voltage of 5.0 V was applied to the obtained evaluation board, placed in a constant temperature and humidity chamber at 130°C and an 85% atmosphere, and the life of the test piece during treatment for 1000 h was evaluated based on the following criteria.

○: 700h or more

△: More than 200h but less than 700h

×: 200h or less

<TCT crack resistance (cold and heat shock resistance)>

The resin compositions of each Example and each Comparative Example were formed on a BT material evaluation substrate, and this test was performed to evaluate crack resistance. An exposure process was performed under the conditions of the evaluation method of <Sensitivity> described above, a PEB process was performed at 90°C for 30 minutes, and then a development process (30°C, 0.2 MPa, 1% by mass Na2CO3 aqueous solution) was performed to form an opening of 200 ㎛ size. A pattern was formed. In addition, in the post-cure process, the coating film was cured under the conditions of 150°C for 60 minutes, and the obtained evaluation board was subjected to -65°C (30 min.) + 175°C (30 min.) using a cold-heat impact tester (manufactured by Kusumoto Kasei Co., Ltd.). After 1000 cycles (one cycle), the presence or absence of cracks in the openings (each 200 μm) was confirmed by observation under an optical microscope, and evaluated based on the following criteria.

◎: Crack incidence rate is less than 10%

○: Crack incidence rate is 10% or more but less than 20%

△: Crack incidence rate is 20% or more and less than 40%

×: Crack incidence rate of 40% or more

<Photo patterning performance>

The resin compositions of each Example and each Comparative Example were formed on a copper-clad substrate, and in order to evaluate photo-patterning properties, an exposure process was performed under the conditions of the evaluation method of <Sensitivity> described above, and a PEB process was performed at 90° C. for 30 minutes. Then, a development process (30°C, 0.2 MPa, 1 mass% Na2CO3 aqueous solution) was performed to form an SRO pattern in 10㎛ units from Φ40㎛ to Φ200㎛. In addition, in the post-cure process, the coating film was cured under the conditions of 150°C for 60 minutes, and the obtained evaluation substrate was observed using an optical microscope adjusted to 100x magnification to evaluate the minimum size at which the opening can be completely formed.

◎: SRO size Φ50㎛ or less

○: SRO size greater than Φ50 and less than Φ60㎛

△: SRO size greater than Φ60 and less than Φ80㎛

×: SRO size greater than Φ80 and less than Φ100㎛

The evaluation results are shown together in Tables 1 and 2.

The materials in Table 1 and Table 2 are as follows.

*1) Photosensitive resin solution containing both an ethylenically unsaturated bond and a carboxyl group (A-1), Mw3,500

*2) Polyamideimide resin solution containing carboxyl group (A-2), Mw4,500

*3) jER834 (bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation), Mw470

*4) IRGACURE OXE-02 (ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(0-acetyl oxime), manufactured by BASF Japan )

*5) Carboxyl group-containing photosensitive resin solution (A-3) (halogen-free, acid-added, acrylate resin, halogen impurity concentration of 5 mass ppm or less), Mw2,000

*6) KAYARAD UXE-3000 (carboxyl group-containing bisphenol A type urethane epoxy acrylate, manufactured by Nippon Kayaku Co., Ltd.), Mw10,000

*7) DPCA-60 (lactone-modified hexaacrylate of dipentaerythritol, manufactured by Nippon Kayaku Co., Ltd.)

*8) NC-3000L (biphenyl aralkyl type epoxy resin, manufactured by Nippon Kayaku Co., Ltd.), Mw700

*9) IRGACURE OXE-02 (ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(0-acetyl oxime), manufactured by BASF Japan )

As is clear from the evaluation results shown in Tables 1 and 2, the laminated structures of each Example had excellent B-HAST resistance and crack resistance, as well as excellent resolution, compared to the laminated structures of each comparative example.

Claims (5)

It is a laminated structure having a two-layer resin layer in which a resin layer (A) containing a resin composition (a) and a resin layer (B) containing a resin composition (b) are laminated,
The resin composition (b) of the resin layer (B) contains an alkali-soluble resin, a photobase generator having the function of a photopolymerization initiator or a photopolymerization initiator and a photobase 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 substantially does not contain a photopolymerization initiator,
After exposing the two resin layers through a step tablet from the resin layer (B) side and performing the PEB process, the coating film thickness of the pattern formed, and the pattern formed by developing after the exposure and performing the PEB process A laminated structure characterized in that the difference between the gloss sensitivity and the residual sensitivity obtained by measuring the film thickness of each is 20 levels or less. The laminate structure according to claim 1, wherein the thickness of the resin layer (B) is 2 μm or more and less than half the thickness of the resin layer (A), and the thickness of the resin layer (A) is 10 to 80 μm. . Characterized by comprising: the laminated structure according to claim 1 or 2, and 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. dry film. 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.