JP2022158998A - Laminate, cured product of the same, and electronic component including the same - Google Patents

Abstract

To provide a laminate which is formed into a cured product having good resolution and circuit concealing property and mechanical physical properties, a cured product of the same, and an electronic component including the same.SOLUTION: There are provided a laminate having a resin layer (A) and a resin layer (B), where one surface of the resin layer (B) is brought into contact with one surface of the resin layer (A), wherein the resin layer (A) has (A1) an alkali-soluble polyamide-imide resin and (A2) an alkali-soluble polyimide resin, and the resin layer (B) has (B1) an alkali-soluble (meth)acrylate resin; a cured product of the same, and an electronic component including the same.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to laminates, particularly laminates that can be used as insulating layers for electronic parts such as printed wiring boards, cured products thereof, and electronic parts containing the same.

An insulating film called a solder resist is formed on the surface layer of printed wiring boards used in various electronic devices. For example, as a method of obtaining a low-gloss solder resist for obtaining circuit hiding properties, it has been proposed to use a specific resin composition as a solder resist composition (for example, Patent Document 1). In Patent Document 1, mutually incompatible components are used as components of a composition for a solder resist to cause irregular reflection of light incident on the surface of the solder resist, thereby reducing glossiness. In another method, it is taught that by roughening the surface of the solder resist layer, the glossiness is suppressed and a solder resist with low gloss is obtained (for example, Patent Document 2). Patent Literature 2 describes obtaining a matted solder resist by a physical surface roughening technique in which a solder resist composition is applied onto a blasted support.

International publication WO2001/058977 JP 2012-141605 A

However, although a general solder resist has a certain degree of hiding power for the circuit of a printed wiring board, there is often a demand for a solder resist having even better hiding power for the circuit in order to improve the appearance of the board.
In addition, since the solder resist described in Patent Document 1 uses the incompatibility of the resin, the entire coating film is unevenly separated, so the mechanical properties of the coating film and the insulation reliability There is room for consideration regarding the securing of

Furthermore, as described in Patent Document 2, in the method of physically transferring the unevenness of the roughened support surface to the resin layer of the solder resist composition or dry film applied thereon, At the time of patterning exposure, the unevenness of the support scatters light, and as a result, the resolution of the solder resist may be affected.

That is, an object of the present invention is to provide a laminate which is excellent in resolution and which is a cured product having excellent circuit hiding properties and mechanical properties, a cured product thereof, and an electronic component having the same.

As a result of intensive studies by the present inventors, the above problem of the present invention has a resin layer (A) and a resin layer (B), and a resin layer (B) is provided on one surface of the resin layer (A). ) is provided so that one surface of the laminate is in contact,
The resin layer (A) is
(A1) an alkali-soluble polyamideimide resin;
(A2) an alkali-soluble polyimide resin;
has
The resin layer (B) is
(B1) It has been found that the above problems can be solved by a laminate characterized by having an alkali-soluble (meth)acrylate resin.
That is, the present inventors have found that a laminate having resin layers (A) and (B) containing the above components can provide a cured product having a matte appearance, thereby improving the circuit hiding property. We have found that an improved solder resist can be obtained. Moreover, according to the laminate of the present invention, a cured product having excellent resolution and excellent mechanical properties can be obtained.

（式（１）中、Ｘ_１は炭素数が２４～４８のダイマー酸由来の脂肪族ジアミン（ａ）の残基、式（２）中、Ｘ_２はカルボキシル基を有する芳香族ジアミン（ｂ）の残基、Ｙはそれぞれ独立にシクロヘキサン環または芳香環である）で示される何れか一方またはその双方の構造を一分子中に有するポリアミドイミド樹脂、またはこれら何れか２種類以上の混合物であると好ましい。 Furthermore, in the laminate of the present invention, (A1) the alkali-soluble polyamideimide resin is represented by the following general formula (1) or (2),

(In the formula (1), X ₁ is the residue of the dimer acid-derived aliphatic diamine (a) having 24 to 48 carbon atoms, and in the formula (2), X ₂ is the aromatic diamine (b) having a carboxyl group. Residues of Y are each independently a cyclohexane ring or an aromatic ring). preferable.

Furthermore, the laminate of the present invention further includes a first film and a second film, and can be provided with the first film, the resin layer (A), the resin layer (B) and the second film in this order. .

Furthermore, the object of the present invention is solved by a cured product obtained by curing the resin layer (A) and the resin layer (B) of the laminate, or an electronic component having the cured product of the laminate.

The laminate of the present invention is a cured product having high circuit hiding power, high resolution, and excellent mechanical properties, and electronic components having such a cured product have similar effects.

1 is a schematic cross-sectional view of a laminate according to an embodiment of the invention; FIG. It is process drawing for demonstrating an example of the manufacturing method of the electronic component containing the laminated body of this invention.

[Laminate]
The laminate of the present invention has a resin layer (A) and a resin layer (B), and is provided so that one surface of the resin layer (B) is in contact with one surface of the resin layer (A). In the laminate, the resin layer (A) is (A1) an alkali-soluble polyamideimide resin, (A2) an alkali-soluble polyimide resin, and the resin layer (B) is (B1) an alkali-soluble ( and a meth)acrylate resin. The resin layer (A) preferably further contains (A3) an epoxy resin and (A4) a photopolymerization initiator, and the resin layer (B) preferably further contains (B2) an epoxy resin. The resin layer (A) of the laminate is formed on the first film, and the resin layer (B) is provided on the surface (opposite side) of the resin layer (A) that does not face the first film to form a laminate. is preferred. It is preferable that a second film is further provided on the surface of the resin layer (B) that does not face the resin layer (A).

The laminate of the present invention is used for manufacturing a printed wiring board as a cured product arranged on a circuit board so that the resin layer (B) is in contact with the circuit board and the resin layer (A) is the outermost layer. preferably.
The resin layer (A) and the resin layer (B) of the laminate of the present invention are arranged so as to be in contact with each other as described above, and cured in this arrangement. In this uncured laminate, the components of the resin layer (A) and the components of the resin layer (B) are mixed at the interface, especially through the heating process. It is speculated that the mixing of the constituent components of the resin layer (A) and the resin layer (B) in this way causes diffuse reflection of visible light at the interface, making it possible to obtain a cured film with excellent circuit hiding properties. be done. By using the laminate of the present invention, it is possible to obtain a circuit concealing property. It is thought that the deterioration of resolution resulting from this does not occur. Furthermore, the laminate of the present invention is excellent in mechanical strength because it does not become non-uniform as a whole. Therefore, by using the laminate of the present invention, it is possible to achieve both circuit concealability, mechanical strength, and resolution.

[Resin layer (A)]
The resin composition constituting the resin layer (A) contains the following components.
((A1) alkali-soluble polyamideimide resin)
The (A1) alkali-soluble polyamideimide resin used in the resin layer (A) of the laminate of the present invention contains at least one alkali-soluble group and is developable with an alkaline solution. Well known and commonly used ones are used.
The alkali-soluble group is a functional group that enables the laminate of the present invention to be developed with an alkaline solution, and includes, for example, a carboxyl group and a phenolic hydroxyl group.
Such an alkali-soluble polyamide-imide resin is, for example, a resin obtained by reacting a carboxylic acid anhydride component and an amine component to obtain an imidized product, and then reacting the obtained imidized product with an isocyanate component. etc. Here, the alkali-soluble group is introduced by using an amine component having a carboxyl group or a phenolic hydroxyl group. Further, the imidization may be carried out by thermal imidization or by chemical imidization, and these may be used in combination.

Examples of the carboxylic anhydride component include tetracarboxylic anhydrides and tricarboxylic anhydrides, but are not limited to these acid anhydrides. Acid anhydride groups that react with amino groups and isocyanate groups and Any compound having a carboxyl group can be used, including its derivatives. 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 carboxyl group, diamines having a phenolic hydroxyl group, and the like can be used. The amine component is not limited to these amines, but it is necessary to use an amine capable of introducing at least one functional group out of phenolic hydroxyl groups and carboxyl groups. 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 polyamideimide resin as described above has a good balance between the alkali solubility (developability) of the polyamideimide resin and other properties such as the mechanical properties of the cured product of the resin composition containing the polyamideimide resin. From the point of view of is particularly preferred. By setting the acid value to 30 mgKOH/g or more, the alkali solubility, that is, developability, is improved, and further, the crosslink density with the thermosetting component after light irradiation is increased, and sufficient development contrast can be obtained. can. Further, by setting the acid value to 150 mgKOH/g or less, it is possible to suppress so-called heat fogging, especially in a PEB (POST EXPOSURE BAKE) step after light irradiation, which will be described later, and to increase the process margin.

Further, the molecular weight of the alkali-soluble polyamideimide resin is preferably 1,000 or more and 20,000 or less, considering the developability and cured coating film properties. 000 is more preferred, and 2,000 to 15,000 is even more preferred. When the molecular weight is 20,000 or less, the alkali-solubility of the unexposed area is increased and the developability is improved. On the other hand, when the molecular weight is 1,000 or more, sufficient development resistance and cured physical properties can be obtained in the exposed area after the exposure/PEB process.
In the present invention, the mass average molecular weight is measured by size exclusion chromatography in accordance with JIS K7252-1:2008 using polystyrene as a molecular weight standard.

（Ｘ１は炭素数が２４～４８のダイマー酸由来の脂肪族ジアミン（ａ）の残基、Ｘ２はカルボキシル基を有する芳香族ジアミン（ｂ）の残基、Ｙはそれぞれ独立にシクロヘキサン環または芳香環である。） In particular, in the present invention, the use of a polyamideimide resin having in one molecule a structure represented by the following general formula (1) or one or both of the structures represented by the following general formula (2) improves developability. It is more preferable in terms of further improvement.

(X1 is a residue of an aliphatic diamine (a) derived from a dimer acid having 24 to 48 carbon atoms, X2 is a residue of an aromatic diamine (b) having a carboxyl group, Y is each independently a cyclohexane ring or an aromatic ring is.)

((A2) alkali-soluble polyimide resin)
The resin composition constituting the resin layer (A) of the laminate of the present invention contains (A2) an alkali-soluble polyimide resin. This (A2) alkali-soluble polyimide resin has the above-described alkali-soluble group.

The (A2) alkali-soluble polyimide resin does not contain an amide bond (--CONH--), and is different from (A1) the alkali-soluble polyamide-imide resin in at least this point.

(A2) The alkali-soluble polyimide resin preferably has at least a carboxyl group as an alkali-soluble group, and particularly preferably has both a carboxyl group and a phenolic hydroxyl group as an alkali-soluble group.

Examples of such (A2) alkali-soluble polyimide resins include resins obtained by reacting a carboxylic anhydride component with an amine component and/or an isocyanate component. Here, the alkali-soluble group is introduced by using an amine component having a carboxyl group or a phenolic hydroxyl group. Further, the imidization may be carried out by thermal imidization or by chemical imidization, and these may be used in combination.

Examples of the carboxylic anhydride component include tetracarboxylic anhydrides and tricarboxylic anhydrides, but are not limited to these acid anhydrides. Acid anhydride groups that react with amino groups and isocyanate groups and Any compound having a carboxyl group can be used, including its derivatives. 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 carboxyl group, diamines having a phenolic hydroxyl group, and the like can be used. The amine component is not limited to these amines, but it is necessary to use an amine into which at least one functional group of phenolic hydroxyl groups and carboxyl groups can be introduced. 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.

In synthesizing such an alkali-soluble polyimide resin (A2), 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.

(A2) The alkali-soluble polyimide resin is used from the viewpoint of improving the balance between the alkali solubility (developability) of the polyimide resin and other properties such as the mechanical properties of the cured product of the laminate containing the polyimide resin. The acid value (solid content acid value) is preferably 20 to 200 mgKOH/g, particularly preferably 60 to 150 mgKOH/g.
In addition, the molecular weight of the alkali-soluble polyimide resin (A2) is preferably a mass average molecular weight Mw of 100,000 or less, more preferably 1,000 to 100,000, in consideration of developability and cured coating properties. Preferably, 2,000 to 50,000 is more preferable.

The total amount of the above (A1) alkali-soluble polyamideimide resin and (A2) alkali-soluble polyimide resin is, with respect to 100 parts by mass of the resin composition constituting the resin layer (A) of the present invention, For example, it is 10 to 85 parts by mass, preferably 30 to 80 parts by mass, and particularly preferably 45 to 75 parts by mass.

Further, the amount of (A2) the alkali-soluble polyimide resin per 100 parts by mass of the solid content of the (A1) alkali-soluble polyamideimide resin is 10 parts by mass or more and 100 parts by mass or less, preferably 20 parts by mass. Above, it is more preferable that it is 70 mass parts or less.

((A3) epoxy resin)
The resin composition constituting the resin layer (A) preferably contains (A3) an epoxy resin.
As the epoxy resin, known and commonly used resins can be used. Resins, hydantoin-type epoxy resins, alicyclic epoxy resins, trihydroxyphenylmethane-type epoxy resins, bixylenol-type or biphenol-type epoxy resins, or mixtures thereof; bisphenol S-type epoxy resins, bisphenol A novolak-type epoxy resins, tetraphenylol Ethane-type epoxy resin, heterocyclic epoxy resin, diglycidyl phthalate resin, tetraglycidyl xylenoyl ethane resin, naphthalene group-containing epoxy resin, epoxy resin having a dicyclopentadiene skeleton, glycidyl methacrylate copolymer epoxy resin, cyclohexylmaleimide and glycidyl methacrylate copolymer epoxy resin, CTBN-modified epoxy resin, and the like. Among these, particularly preferable (A3) epoxy as a component of the resin layer (A) is a bisphenol A type epoxy resin, a novolak type epoxy, or a combination thereof.

(A3) Specific examples of the epoxy resin include jER828, jER834, jER1001, and jER1004 manufactured by Mitsubishi Chemical Corporation; EPICLON 840, 850, 850-S, 1050, and 2055 manufactured by DIC; YD-011, YD-013, YD-127, YD-128, Dow Chemical Company D.I. E. R. 317, D. E. R. 331, D. E. R. 661, D. E. R. 664, Sumie-epoxy ESA-011, ESA-014, ELA-115, ELA-128, etc. (all trade names) manufactured by Sumitomo Chemical Co., Ltd.; jERYL903 manufactured by Mitsubishi Chemical Co., Ltd.; EPICLON 152, 165, Epotote YDB-400 and YDB-500 manufactured by Nippon Steel Chemical & Materials, D.I. manufactured by Dow Chemical. E. R. 542, Sumie-epoxy ESB-400, ESB-700, etc. (both trade names) manufactured by Sumitomo Chemical Co., Ltd.; jER152 and jER154 manufactured by Mitsubishi Chemical Co., Ltd.; E. N. 431, D. E. N. 438, EPICLON N-730, N-770, N-865 manufactured by DIC, Epotato YDCN-701, YDCN-704 manufactured by Nippon Steel Chemical & Materials, EPPN-201, EOCN-1025 manufactured by Nippon Kayaku, EOCN-1020, EOCN-104S, RE-306, NC-3000, NC-3000L, Sumitomo Chemical Co., Ltd. Sumy-Epoxy ESCN-195X, ESCN-220, Nippon Steel Chemical & Material Co., Ltd. YDCN-700-2, YDCN-700-3, YDCN-700-5, YDCN-700-7, YDCN-700-10, YDCN-704 YDCN-704A, DIC EPICLON N-680, N-690, N-695 (both Novolac type epoxy resin such as trade name); EPICLON 830 manufactured by DIC, jER807 manufactured by Mitsubishi Chemical Corporation, Epotato YDF-170, YDF-175, YDF-2004 manufactured by Nippon Steel Chemical & Materials Co., Ltd. (all trade names) Bisphenol F type epoxy resin; Epotote ST-2004, ST-2007, ST-3000 (trade name) manufactured by Nippon Steel Chemical & Materials Co., Ltd., hydrogenated bisphenol A type epoxy resin such as YX8034 manufactured by Mitsubishi Chemical Corporation; Mitsubishi Chemical Glycidylamine type epoxy resins such as jER604 manufactured by Nippon Steel Chemical & Materials Co., Ltd., Epotote YH-434 manufactured by Nippon Steel Chemical & Materials Co., Ltd., and Sumi-Epoxy ELM-120 manufactured by Sumitomo Chemical Co., Ltd. (all are trade names); Hydantoin type epoxy resins; Alicyclic epoxy resins such as Celoxide 2021 (both trade names) manufactured by Mitsubishi Chemical Corporation; Trihydroxy resins such as YL-933 manufactured by Mitsubishi Chemical Corporation, EPPN-501 and EPPN-502 manufactured by Nippon Kayaku Co., Ltd. (both trade names) Phenylmethane type epoxy resin; Mitsubishi Chemical Corp. YL-6056, YX-4000, YL-6121 (all trade names) and other bixylenol type or biphenol type epoxy resins or mixtures thereof; Nippon Kayaku Co., Ltd. EBPS- 200, ADEKA EPX-30, DIC EXA-1514 (trade name) and other bisphenol S type epoxy resins; Mitsubishi Chemical Corp. jER157S (trade name) and other bisphenol A novolac type epoxy resins; Mitsubishi Chemical Corp. Tetraphenylol ethane type epoxy resin such as jERYL-931 (both trade names) manufactured by Nissan Chemical Co., Ltd. Heterocyclic epoxy resin such as TEPIC (both trade names); Diglycidyl phthalate resins such as DGT; tetraglycidyl xylenoyl ethane resins such as ZX-1063 manufactured by Nippon Steel Chemical &Materials; ESN-190 and ESN-360 manufactured by Nippon Steel Chemical &Materials; HP-4032 manufactured by DIC; Naphthalene skeleton-containing epoxy resins such as EXA-4750 and EXA-4700; Epoxy resins having a dicyclopentadiene skeleton such as HP-7200 and HP-7200H manufactured by DIC Corporation; Glycidyl such as CP-50S and CP-50M manufactured by NOF Corporation methacrylate-copolymerized epoxy resins; copolymerized epoxy resins of cyclohexylmaleimide and glycidyl methacrylate; CTBN-modified epoxy resins (eg YR-102, YR-450, etc. manufactured by Nippon Steel Chemical & Materials Co., Ltd.), and the like.
In the resin layer (A), (A3) the epoxy resin may be in any amount, but the alkali contained in (A1) the alkali-soluble polyamideimide resin and (A2) the alkali-soluble polyimide resin It is preferable that the ratio of the soluble group (phenolic hydroxyl group, carboxyl group) equivalent to the epoxy equivalent of the (A3) epoxy resin is 1:0.1 to 1:10.

By setting the compounding ratio within such a range, the development is improved, and a fine pattern can be easily formed with high accuracy. More preferably, the equivalent ratio is 1:0.2 to 1:5.

((A4) photopolymerization initiator)
The resin composition constituting the resin layer (A) preferably contains (A4) a photopolymerization initiator.
(A4) The photopolymerization initiator is one selected from the group consisting of an oxime ester photopolymerization initiator having an oxime ester group, an α-aminoacetophenone photopolymerization initiator, and an acylphosphine oxide photopolymerization initiator. The above photopolymerization initiators can be preferably used.

Examples of the oxime ester photopolymerization initiator include commercial products such as IRUGACURE OXE01 and IRUGACURE OXE02 manufactured by BASF Japan, N-1919 and NCI-831 manufactured by Adeka Corporation. A photopolymerization initiator having two oxime ester groups in the molecule can also be preferably used.

As the α-aminoacetophenone-based photopolymerization initiator, specifically, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl)-butan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, N , N-dimethylaminoacetophenone, and the like. Commercially available products include IGM Resins B.I. Omnirad 907, Omnirad 369, Omnirad 379 manufactured by V company, and the like.

Specific examples of acylphosphine oxide photopolymerization initiators include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxy benzoyl)-2,4,4-trimethyl-pentylphosphine oxide and the like. Commercially available products include IGM Resins B.I. Omnirad 819 manufactured by V company and the like can be mentioned.

(A4) As the photopolymerization initiator, a photopolymerization initiator that also functions as a photobase generator is preferably used when used in the PEB step after photoirradiation, which will be described later. In this PEB step, a photopolymerization initiator and a photobase generator may be used together.

The photopolymerization initiator, which also functions as a photobase generator, changes its molecular structure by irradiation with light such as ultraviolet light or visible light, or when the molecule is cleaved, the polymerization reaction of the thermosetting resin described later is initiated. 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 photopolymerization initiators that also function as photobase generators include the above-mentioned α-aminoacetophenone compounds, oxime ester compounds, acyloxyimino groups, N-formylated aromatic amino groups, N- Compounds having a substituent such as an acylated aromatic amino group, a nitrobenzylcarbamate group, an alkoxybenzylcarbamate group, and the like are included.

As these photopolymerization initiators, it is particularly preferable to use at least one of oxime ester photopolymerization initiators, α-aminoacetophenone photopolymerization initiators, and acylphosphine oxide photopolymerization initiators. (A4) The amount of the photopolymerization initiator is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass, based on the total solid content in the resin layer (A). is more preferable. When it is 0.1% by mass or more, the photocurability on copper is improved, the adhesion of the coating film is improved, and the coating film properties such as chemical resistance are also improved. On the other hand, by making it 20% by mass or less, the effect of reducing outgassing can be obtained.

[Resin layer (B)]
The resin composition constituting the resin layer (B) contains the following components.
((B1) alkali-soluble (meth)acrylate resin)
As the (B1) alkali-soluble (meth)acrylate resin used in the present invention, those derived from a carboxyl group and a (meth)acryloyl group or derivatives thereof in the molecule are preferable. (B1) As specific examples of the alkali-soluble (meth)acrylate resin, the following compounds (both oligomers and polymers may be used) can be suitably used.

(1) Diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates, bisphenol A epoxy resins, hydrogenated bisphenol A epoxy resins, bisphenol F epoxy resins, and bisphenol S epoxy resins , bixylenol-type epoxy resin, biphenol-type epoxy resin, etc. (meth)acrylate or its partial acid anhydride-modified product with a carboxyl group-containing dialcohol compound and a diol compound, resulting in alkali solubility due to a polyaddition reaction urethane-based (meth)acrylate resin.

(2) During the synthesis of the resin of (1) 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 terminally (meth)acrylate. Alkali-soluble urethane-based (meth)acrylate resin.

(3) During the synthesis of the resin in (1) above, a compound having 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, is added. Alkali-soluble urethane-based (meth)acrylate resin with terminal (meth)acrylate.

(4) Alkali-soluble (meth)acrylate obtained by reacting (meth)acrylic acid with a polyfunctional (solid) epoxy resin having a functionality of 2 or more and adding a dibasic acid anhydride to the hydroxyl group present in the side chain. resin.

(5) Alkali obtained by reacting (meth)acrylic acid with a polyfunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of a bifunctional (solid) epoxy resin with epichlorohydrin, and adding a dibasic acid anhydride to the resulting hydroxyl groups Soluble (meth)acrylate resin.

(6) A reaction product obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide is reacted with (meth)acrylic acid, and the resulting reaction product is Alkali-soluble (meth)acrylate resin obtained by reacting polybasic acid anhydride.

(7) 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 and reacting (meth)acrylic acid with the reaction product. Alkali-soluble (meth)acrylate resin obtained by reacting a polybasic acid anhydride with a substance.

(8) An alkali-soluble (meth)acrylate resin obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule to the resins of (1) to (7) above. .
In this specification, (meth)acrylate is a generic term for acrylate, methacrylate and mixtures thereof, and the same applies to other similar expressions.

Since the (B1) alkali-soluble (meth)acrylate resin as described above has a large number of carboxyl groups in the side chains of the backbone polymer, development with a dilute aqueous alkali solution is possible.
The acid value of (B1) alkali-soluble (meth)acrylate resin is suitably in the range of 40 to 200 mgKOH/g, more preferably in the range of 45 to 120 mgKOH/g. (B1) When the acid value of the alkali-soluble (meth)acrylate resin is 40 mgKOH/g or more, good alkali development is achieved. A normal resist pattern can be drawn without occurrence of thinning of the line more than necessary, the distinction between the exposed area and the unexposed area is maintained, and dissolution and peeling by the developer does not occur.

Further, the mass average molecular weight of (B1) the alkali-soluble (meth)acrylate resin varies depending on the resin skeleton, but is generally in the range of 1,000 to 150,000, further 2,000 to 100,000. things are preferred. When the weight-average molecular weight is 2,000 or more, the tack-free property is good, the moisture resistance of the coating film after exposure is sufficient, development is performed as designed, and the resolution is improved. On the other hand, when the weight average molecular weight is 150,000 or less, excellent developability can be stably obtained, and storage stability is also improved.

The amount of such an alkali-soluble (meth)acrylate resin (B1) is 20 to 80% by mass, preferably 30 to 70% by mass, based on the solid content of the resin composition constituting the resin layer (B). %. (B1) When the content of the alkali-soluble (meth)acrylate resin is 20% by mass or more, the film strength is improved. On the other hand, when the amount is 80% by mass or less, the viscosity of the resin composition is considered favorable, and the coatability is improved, which is preferable. .

These (B1) alkali-soluble (meth)acrylate resins are not limited to those listed above, and may be used singly or in combination. Among alkali-soluble (meth)acrylate resins, resins having an aromatic ring are particularly preferable because they have a high refractive index and excellent resolution. It is preferable because it is excellent in PCT and crack resistance. Among them, it is preferable to use the alkali-soluble (meth)acrylate resins listed in (4), (6), and (7). (Meth)acrylate resins having excellent HAST resistance and PCT resistance can be suitably used.

In the present invention, the (B1) alkali-soluble (meth)acrylate resin ((B1) component) is the (A1) alkali-soluble amide imide resin ((A1) component) contained in the resin layer (A) and the (A2) It is thought to exhibit incompatibility with at least one of the alkali-soluble polyimide resins (component (A2)). That is, a mixture of the (A1) component, the (A2) component, and the (B1) component, or a mixture of the resin compositions for forming the resin layers (A) and (B) containing these, is the resin layer (A) and the resin layer At the interface of (B), an immiscible mixed state is formed, and as a result, the interface between the two layers loses smoothness and becomes uneven. It is presumed that when visible light is incident on the uneven interface, the visible light is diffusely reflected, and the circuit of the electronic component is better concealed.

((B2) epoxy resin)
The resin composition constituting the resin layer (B) preferably contains (B2) an epoxy resin. As the (B2) epoxy resin, the same epoxy resin as the (A3) epoxy resin described above as a component of the resin layer (A) can be used. The (A3) epoxy resin and (B2) epoxy resin used for the resin layer (A) and the resin layer (B) of the laminate may be of the same type or different types. good. Furthermore, when a plurality of types of epoxy resins are used for either or both of the resin layer (A) and the resin layer (B), some of them may be of the same type.

The (B2) epoxy resin in the resin layer (B) may be in any amount, but the alkali-soluble group (phenolic hydroxyl group, carboxyl group) of the (B1) alkali-soluble (meth)acrylate resin It is preferable that the ratio of the equivalent weight to the epoxy equivalent weight of the (B2) epoxy resin is 1:0.1 to 1:10.

By setting the compounding ratio within such a range, the development is improved, and a fine pattern can be easily formed with high accuracy. More preferably, the equivalent ratio is 1:0.2 to 1:5.

[Optional Components of Resin Layer (A) and Resin Layer (B)]
The resin layer (A) and resin layer (B) may further contain the following components.

(Photopolymerizable compound)
The resin layers (A) and (B) may contain a photopolymerizable compound, and any photopolymerizable compound conventionally used in the production of solder resists and the like can be used.

The photopolymerizable compounds that can be contained in the resin layers (A) and (B) include compounds having two or more ethylenically unsaturated groups in the molecule, α,β-unsaturated carboxylic acids added to polyhydric alcohols. A compound obtained by addition, a compound obtained by adding an α,β-unsaturated carboxylic acid to a glycidyl group-containing compound, and the like.

Compounds having two or more ethylenically unsaturated groups in the molecule include, for example, glycol diacrylates such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol and propylene glycol; hexanediol, trimethylolpropane, pentaerythritol , dipentaerythritol, tris-hydroxyethyl isocyanurate and other polyhydric alcohols, or polyhydric acrylates such as their ethyloxide adducts or propylene oxide adducts; phenoxy acrylate, bisphenol A diacrylate, and ethylene of these phenols polyvalent acrylates such as oxide adducts or propylene oxide adducts; polyvalent acrylates of glycidyl ethers such as glycerol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, triglycidyl isocyanurate; and melamine acrylate, and at least one of methacrylates corresponding to the above acrylates.

Compounds obtained by adding an α,β-unsaturated carboxylic acid to a polyhydric alcohol include, for example, ethylene glycol diacrylate, diethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, propylene glycol diacrylate, and polypropylene. glycol diacrylate, butylene glycol diacrylate, pentyl glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, tetramethylolmethane triacrylate, tetramethylolmethane tetraacrylate, glycerin diacrylate , pentaerythritol diacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and the like, and at least one of methacrylates corresponding to the above acrylates.

Compounds obtained by adding an α,β-unsaturated carboxylic acid to a glycidyl group-containing compound include, for example, ethylene glycol diglycidyl ether diacrylate, diethylene glycol diglycidyl ether diacrylate, trimethylolpropane triglycidyl ether triacrylate, and bisphenol A. glycidyl ether diacrylate, phthalic acid diglycidyl ester diacrylate, glycerin polyglycidyl ether polyacrylate, etc.; 2,2-bis(4-acryloyloxydiethoxyphenyl)propane, 2,2-bis-(4-acryloyloxy polyethoxyphenyl)propane, 2-hydroxy-3-acryloyloxypropyl acrylate, and at least one of methacrylates corresponding to the above acrylates. The above photopolymerizable compounds can be used singly or in combination of two or more.

Further, the photopolymerizable compound includes urethane acrylate, polyester acrylate, epoxy acrylate, and the like for the purpose of imparting toughness to the cured product. In addition, for the purpose of viscosity adjustment, monofunctional (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, ) acrylate, 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, glycidyl methacrylate and other (meth)acrylates, acryloylmorpholine and the like can also be used.
(Inorganic filler)
Inorganic fillers can be added in order to suppress curing shrinkage of the cured product and improve properties such as adhesion and hardness. Examples of such inorganic fillers include barium sulfate, amorphous silica, fused silica, spherical silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, aluminum nitride, boron nitride, and Neuburg Silicious Earth.

(Thermosetting catalyst)
The resin layers (A) and (B) can contain a thermosetting catalyst. Examples of thermosetting catalysts include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- Imidazole derivatives such as (2-cyanoethyl)-2-ethyl-4-methylimidazole; dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzyl amines, amine compounds such as 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; and phosphorus compounds such as triphenylphosphine. In addition, commercially available products include, for example, 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, and 2P4MHZ manufactured by Shikoku Kasei Co., Ltd. (all are trade names of imidazole compounds), and U-CAT manufactured by San-Apro Co., Ltd. 3513N (trade name of dimethylamine compound), DBU, DBN, U-CAT SA 102 (all bicyclic amidine compounds and salts thereof), and the like. These can be used alone or in combination of two or more.

Furthermore, guanamine, acetoguanamine, benzoguanamine, melamine, tetrahydrophthalic anhydride addition melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2- S-triazine derivatives such as vinyl-4,6-diamino-S-triazine/isocyanuric acid adduct and 2,4-diamino-6-methacryloyloxyethyl-S-triazine/isocyanuric acid adduct can also be used. One type of thermosetting catalyst may be used alone, or two or more types may be used in combination.

(coloring agent)
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.

(Organic solvent)
The organic solvent can be blended for the production of the resins to be the components for the resin layers (A) and (B), the production of the resin composition containing these, or the adjustment of the viscosity. Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, and petroleum solvents. Such organic solvents may be used singly or as a mixture of two or more.

(Other ingredients)
Further components such as mercapto compounds, adhesion promoters, antioxidants, and ultraviolet absorbers can be blended as necessary. Known and commonly used materials can be used as these materials. In addition, known and commonly used thickeners such as finely divided silica, hydrotalcite, organic bentonite, and montmorillonite, antifoaming agents and/or leveling agents such as silicone-based, fluorine-based, and polymer-based agents, silane coupling agents, and rust inhibitors. Known and commonly used additives such as these can be blended.

(Manufacturing process of laminate)
A production example of the laminate (dry film) of the present invention will be described with reference to FIG.
FIG. 1 shows a cross-sectional view of one embodiment of the laminate of the present invention. In FIG. 1, the laminate 10 is prepared by diluting the resin composition constituting the resin layer (A) on the first film 1 with an organic solvent to adjust the viscosity to an appropriate value, followed by a comma coater according to a conventional method. It is applied by a known method such as. After that, it is usually dried at a temperature of 50 to 140° C. for 1 to 30 minutes to form a dry coating film of the resin layer (A) on the first film 1 . On the resin layer (A) thus obtained, the resin composition constituting the resin layer (B) is further diluted with an organic solvent to adjust the viscosity to an appropriate level, and is coated with a comma coater or the like according to a conventional method. It is applied by a known method. Thereafter, it is usually dried at a temperature of 50 to 140° C. for 1 to 30 minutes to form a dry coating film of the resin layer (B) on the surface of the resin layer (A) opposite to the first film 1. .

Application of the resin composition for forming the resin layers (A) and (B) can be performed by known equipment such as a blade coater, a lip coater, a film coater, etc. in addition to the comma coater described above. Is preferably carried out by using a device equipped with a steam heating type heat source such as a hot air circulation drying furnace, an IR furnace, a hot plate, a convection oven, etc. A known method such as a spraying method can also be used.

In addition, on the resin layer (B) of the laminate, that is, on the surface of the resin layer (B) of the laminate opposite to the resin layer (A), dust is prevented from adhering to the surface of the resin layer. For such purposes, a peelable second film 2 can be further laminated. As the first film 1 and the second film 2, conventionally known plastic films can be appropriately used.

The adhesive force between the second film 2 and the resin layer (B) is preferably smaller than the adhesive force between the first film 1 and the resin layer (A). Since the laminate 10 of the present invention is placed on an electronic device after first peeling off the second film 2, this work is facilitated by controlling the adhesive force as described above. The thicknesses of the first film 1 and the second film 2 are not particularly limited, but are generally selected appropriately within the range of 10 to 150 μm.
Thus, a laminate having a four-layer structure in which the first film 1, the resin layer (A), the resin layer (B), and the second film 2 are laminated in this order is manufactured as a dry film.
Also, the laminate of the present invention may be supported or protected with a film (either the first film 1 or the second film 2) on only one side, or may be a laminate containing no film. Furthermore, the laminate (dry film) of the present invention may be wound into a roll.

From the viewpoint of coating film strength, the interface between each layer may be familiar. That is, the resin layer (A) and the resin layer (B) have high adhesion, and when the first film 1 or the second film 2 is peeled off, or when there are other layers to be peeled off as a laminate, It is preferable that the resin layer (A) and the resin layer (B) adhere to each other when the layers to be peeled off form a highly durable permanent film.

The laminate obtained as described above is applied to electronic devices (to be protected) such as printed wiring boards, and functions as a solder resist or the like. The laminate of the present invention is laminated so that the resin layer (B) is on the electronic component side and the resin layer (A) is on the surface layer side when the laminate of the present invention is laminated on an object to be protected.

When the laminate of the present invention is placed on an electronic device, if the laminate has the second film 2, it is peeled off and the resin layer (B) covers the surface to be protected of the circuit board. By arranging them facing each other and applying pressure using a laminator, the laminate and the electronic device are brought into close contact with each other. As the laminator, a commercially available vacuum heating and pressurizing laminator can be used. For example, a vacuum pressurized laminator manufactured by Meiki Seisakusho, a vacuum applicator manufactured by Nichigo-Morton, etc. can be used. In this case, in addition to the above-described vacuum heating and pressurizing laminator, a roll laminator, a vacuum roll laminator, a vacuum press, or the like can also be used. Commercially available general equipment can be applied to the vacuum press. The operating conditions of the above laminator, etc., can be performed at 60 to 130 ° C., pressure 0.1 to 0.7 MPa, heating and pressurizing time 1 to 90 seconds, degree of vacuum 10 to 10,000 Pa, vacuum time 1 to 90 A range of seconds can be processed.

Further, as a method for disposing the laminate of the present invention on a circuit board, the resin layer (A) and the resin layer (B) are individually prepared as dry films, and the dry films are applied to the surface to be protected of the circuit board. A method of sequentially laminating can also be used. That is, first, the resin layer (B) is formed on the circuit board by laminating the dry film of the resin layer (B) on the circuit board. After that, by laminating the dry film of the resin layer (A) on the resin layer (B), the laminate of the present invention formed on the circuit board can be obtained.

In the present invention, "above" and "opposite" do not necessarily mean that the layers, surfaces, etc. described as objects are in contact, and in some cases they may be provided via another layer. be. On the other hand, "directly" or the like means a state in which layers or surfaces are in contact with each other.

In addition, the resin composition for the resin layer (B) is directly applied to the circuit board, dried, and then the resin for the resin layer (A) is applied onto the dried resin layer (B). A laminate may be formed by applying and drying the composition. In this case, the laminate (dry film) is formed by laminating the resin layer (B) and the resin layer (A) in order from the circuit board side, and the resin layers (B) and (A) are laminated on the circuit board. The layered body of the present invention is constructed in a layered state. Even when directly provided on the circuit board in this way, viscosity adjustment using an organic solvent of the resin composition, application, drying, etc. are performed in the same manner as in the case of producing a laminate using the first film 1. .

In producing the resin composition, the organic solvent used for adjusting the viscosity is appropriately selected from the known organic solvents as described above.

The laminate thus produced is cured by a curing treatment described below to constitute a permanent coating on an electronic device (protection target) such as a printed wiring board.
The laminate of the present invention can be preferably used for forming a protective film for electronic parts, particularly for printed wiring boards, and is particularly preferably used for forming permanent protective films such as solder resist layers and coverlays for flexible printed wiring boards. can. Although the printed wiring board is not particularly limited, the laminate of the present invention has high resolution and is excellent in mechanical properties, so that it can be suitably used as a package substrate.

(Method for Producing Cured Product and Electronic Component Containing Cured Product)
An example of a method for manufacturing an electronic component including the laminate 10 of the present invention will be described with reference to the process diagrams of FIGS.
FIG. 2 shows the step (a) (lamination step) of forming the laminate (dry film) 10 of the present invention on a printed wiring board 20 on which a conductor circuit is formed, and irradiating the laminate with an active energy ray in a pattern. The manufacturing method includes step (b) (exposure step) and step (d) (development step) of forming a patterned laminate collectively by developing the laminate with an alkali. Further, if necessary, after the alkali development, a step (e) (post-cure step) of further photocuring or heat-curing is performed to completely cure the laminate to obtain a highly reliable printed wiring board. can be done. Furthermore, if necessary, the step (c) (PEB step) of heating the laminate may be inserted between the exposure step and the development step to collectively form a patterned laminate by the development step. Furthermore, when the resin layer (A) contains a compound that generates a basic substance upon irradiation with light, it is preferable to perform the PEB step from the viewpoint of resolution. In the development step, the resin layers (A) and (B) are developed simultaneously (batch) through the exposure and optional PEB steps, so this is referred to as “batch formation” above. there is

[Step a: Lamination step]
In this step, the resin composition that constitutes the resin layer (B) and the resin layer (A) is directly applied onto the printed wiring board 20 on which the conductor circuit 21 is formed, and then dried. By directly forming the resin layer (B) and the resin layer (A) on the printed wiring board 20, or forming the resin layer (B) and the resin layer (A) in advance as described above in the form of a dry film The resulting laminate 10 is laminated on the printed wiring board 20 . Alternatively, as described above, the resin layer (A) and the resin layer (B) are individually laminated as dry films on the printed wiring board 20 in sequence.

In step (a) of FIG. 2 , a dry film prepared in advance as the resin layer (B) on the resin layer (A) is laminated on the printed wiring board 20 . Laminate 10 is preferably laminated to printed wiring board 20 under pressure and heat using a vacuum laminator or the like. By using such a vacuum laminator, even if the surface of the printed wiring board 20 has unevenness, the dry film 10 adheres to the wiring base material, so there is no entrapment of air bubbles. The hole-filling property is also improved. As the conditions for vacuum lamination, the above conditions can be appropriately selected and used.

[Step (b): Exposure step]
In step (b), a negative mask 3 is placed on the upper surface of the resin layer (A). By irradiation with active energy rays, the photopolymerization initiator contained in the resin layer (A) or the resin layer (B) is activated in a negative pattern, and the exposed area is cured. As an exposure machine, an exposure machine equipped with a metal halide lamp or the like can be used. It is also possible to omit the arrangement of the mask 3 and perform activation energy irradiation by a direct drawing apparatus.

As active energy rays used for exposure, it is preferable to use laser light, scattered light, or parallel light having a maximum wavelength in the range of 350 to 450 nm. By setting the maximum wavelength within this range, the photopolymerization initiator can be efficiently activated. Also, the amount of exposure varies depending on the film thickness and the like, but it can usually be 50 to 1500 mJ/cm ² . In the present invention, the laminate 10 after being subjected to the exposure process and cured is referred to as a cured product of the laminate 10 .

[Step (c) PEB step]
After the exposure, the exposed portion can be cured by heating the resin layer as an optional step (c). This heating process is called a PEB (POST EXPOSURE BAKE) process, which suppresses curing shrinkage of the laminate 10 after photolithography, and can give excellent resolution to the laminate 10 after curing. . When the resin layer (A) and the resin layer (B) contain a photopolymerization initiator functioning as a photobase generator, or both a photopolymerization initiator and a photobase generator, the photobase generator generated in the exposure step The base can harden the resin layer (A) and the resin layer (B) to the depth. The heating temperature is, for example, 70 to 140°C, preferably 80 to 140°C. The heating time is, for example, 2 to 100 minutes, preferably 10 to 100 minutes. In the PEB process, curing proceeds mainly through ring-opening reaction of epoxy resin or the like due to heat reaction, so distortion and curing shrinkage can be suppressed compared to the case where curing is performed by photoradical reaction in the exposure process. As the PEB process, the exposed portion may be cured by heating the layer of the dry film between the exposure process and the development process.

[Step (d): Development step]
In this step (d), the unexposed portions are removed by alkali development, and the laminate 10 cured in a negative pattern is formed, particularly as a coverlay and a solder resist. As a developing method, a known method such as dipping can be used. As the developer, sodium carbonate, potassium carbonate, potassium hydroxide, amines, imidazoles such as 2-methylimidazole, alkaline aqueous solutions such as tetramethylammonium hydroxide aqueous solution (TMAH), or mixtures thereof. can be used.

[Step (e): Post-cure step]
After the development step (d), the cured product of the laminate 10 may be further irradiated with light, or heated at 150° C. or higher, for example. The heating temperature is, for example, 80 to 170° C., and the heating time is 5 to 100 minutes. Since the post-curing of the laminate 10 in the present invention is, for example, a ring-opening reaction of the epoxy resin by thermal reaction, it is possible to suppress distortion and cure shrinkage compared to the case where curing proceeds by photoradical reaction.
As described above, the electronic component 100 including the cured product of the laminate 10 of the present invention is manufactured.

The cured product of the present invention exhibits functions such as a solder resist in the electronic component of the present invention. In electronic parts, the cured product is formed such that the resin layer (A) is the outermost layer. Since the cured product of the present invention has excellent resolution, it is possible to form fine patterns and improve the quality of electronic parts. Furthermore, it can well hide the circuits of electronic parts, and exhibits excellent mechanical properties.

In the present invention, an electronic component means a component having an electronic circuit, and includes active components such as printed wiring boards, transistors, light emitting diodes, and laser diodes, as well as passive components such as resistors, capacitors, inductors, and connectors. . The cured product of the laminate of the present invention provides mechanical properties as an insulating layer of these electronic parts and good circuit concealability.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. The values of "parts" and "%" in the examples and comparative examples are based on mass unless otherwise specified.

<Preparation of resin composition>
I. Synthesis of Resin Component [Synthesis Example 1: Synthesis of polyamideimide resin solution having carboxyl group (alkali-soluble polyimideimide resin 1) (either one or both of general formula (1) or (2) Polyamideimide resin possessed in one molecule)]
3.8 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, nitrogen inlet tube, fractionation ring, and cooling ring. 6.98 g of phenyl]propane, 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 (25°C).

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. Then, 30 g of toluene was added, the temperature was raised to 160° C., and the mixture was stirred for 3 hours while toluene and water were distilled off, and then cooled to room temperature to obtain an imide solution.

9.61 g of trimellitic anhydride and 17.45 g of trimethylhexamethylene diisocyanate were added to the imidized product solution obtained, and the mixture was stirred at a temperature of 160° C. for 32 hours. Thus, a polyamide-imide resin solution having carboxyl groups was obtained. The obtained resin solution (resin 1) had a solid content of 40.1% by mass and an acid value of the solid content of 88.1 mgKOH.

[Synthesis Example 2: Synthesis of polyimide resin solution having phenolic hydroxyl group and carboxyl group (alkali-soluble polyimide resin 2)]
22.4 g of 3,3′-diamino-4,4′-dihydroxydiphenylsulfone, 2,2′-bis[4 8.2 g of -(4-aminophenoxy)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, Under nitrogen atmosphere, the mixture was stirred at room temperature and 100 rpm for 4 hours. Next, 20 g of toluene was added, and the mixture was stirred for 4 hours at a silicone bath temperature of 180° C. and 150 rpm while toluene and water were distilled off to obtain a polyimide resin solution (resin 2) having phenolic hydroxyl groups and carboxyl groups. The obtained resin (solid content) had an acid value of 18 mg KOH, an Mw of 10,000, and a hydroxyl equivalent of 390.

[Synthesis Example 3: Synthesis of carboxyl group-containing novolak-type acrylate resin (alkali-soluble (meth)acrylate resin 3)]
An autoclave equipped with a thermometer, a nitrogen introduction device and an alkylene oxide introduction device, and a stirring device was charged with 119.4 g of a novolak cresol resin (manufactured by Aica Kogyo Co., Ltd., trade name "Shonol CRG951", OH equivalent: 119.4), 1.19 g of potassium hydroxide and 119.4 g of toluene were charged, and the inside of the system was replaced with nitrogen while stirring, followed by heating. Next, 63.8 g of propylene oxide was gradually added dropwise and reacted at 125-132° C. and 0-4.8 kg/cm 2 for 16 hours. After cooling to room temperature, 1.56 g of 89% phosphoric acid was added to the reaction solution to neutralize the potassium hydroxide. A propylene oxide reaction solution of a novolak-type cresol resin was obtained. This was obtained by adding an average of 1.08 mol of alkylene oxide per equivalent of phenolic hydroxyl group. Next, 293.0 g of the alkylene oxide reaction solution of the novolak type cresol resin obtained, 43.2 g of acrylic acid, 11.53 g of methanesulfonic acid, 0.18 g of methylhydroquinone and 252.9 g of toluene were mixed with a stirrer, a thermometer and air. The mixture was charged into a reactor equipped with a blowing tube, air was blown in at a rate of 10 ml/min, and the mixture was reacted at 110° C. for 12 hours while stirring. 12.6 g of water was distilled out as an azeotrope with toluene, which was produced by the reaction. After cooling to room temperature, the resulting reaction solution was neutralized with 35.35 g of a 15% aqueous sodium hydroxide solution and then washed with water. After that, the toluene was removed by an evaporator while replacing it with 118.1 g of diethylene glycol monoethyl ether acetate to obtain a novolac type acrylate resin solution. Next, 332.5 g of the obtained novolak-type acrylate resin solution and 1.22 g of triphenylphosphine were charged into a reactor equipped with a stirrer, a thermometer and an air blowing pipe, and air was blown at a rate of 10 ml/min. While stirring, 60.8 g of tetrahydrophthalic anhydride was gradually added and reacted at 95-101° C. for 6 hours. Thus, a solution of a carboxyl group-containing photosensitive resin (resin 3) having a solid content acid value of 88 mgKOH/g, a solid content of 71%, and a mass average molecular weight of 2,000 was obtained.

II. Preparation of Resin Compositions for Resin Layers (A) and (B) According to the formulations of resin layers (A) and (B) shown in Table 1 below, each component was premixed with a stirrer and then kneaded with a three-roll mill. Then, each resin composition was prepared.

＊上記表中の各成分の割合は固形分による。 Table 1

*The ratio of each component in the table above is based on the solid content.

Details of each component described in Table 1 are as follows.
Polyamideimide resin: Alkali-soluble polyamideimide resin synthesized in Synthesis Example 1 Polyimide resin: Alkali-soluble polyimide resin synthesized in Synthesis Example 2 Epoxy resin ((A3) and (B2)): Bisphenol A type novolak epoxy resin (manufactured by DIC)
Photopolymerization initiator: oxime ester photopolymerization initiator IRUGACURE OXE 02 (manufactured by BASF Japan)
Acrylate resin 1: KAYARAD ZCR-1569H (dibasic acid anhydride adduct of polyfunctional epoxy (meth)acrylate, alkali-soluble (meth)acrylate resin) (manufactured by Nippon Kayaku Co., Ltd.)
DHPA: dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.)
Coloring pigment: Paliogen Black S0084 (perylene black pigment) (manufactured by BASF)
Acrylate resin 2: Alkali-soluble (meth)acrylate resin synthesized according to Synthesis Example 3 * By using matte PET (PTHA-25, manufactured by Unitika Ltd., surface roughness Ra: 0.3 μm) as the first film , unevenness was formed on the surface of the resin layer (A)

III. Preparation of Laminate and Evaluation of Cured Product III-1. Preparation of Laminate (Dry Film) Each resin composition obtained as described above was diluted with an organic solvent methyl ethyl ketone to obtain an appropriate viscosity (10 mPa s). ~100 dPa·s). On the first film (PET film, thickness: 25 μm, surface roughness (Ra): 0.03 μm), a resin composition corresponding to the resin layer (A) described in Table 1 is added to the resin layer (A). After drying, the coating was applied so that the film thickness was as shown in the same table, and dried at 90° C. for 15 minutes. Next, on the dried resin layer (A), a resin composition corresponding to the resin layer (B) in Table 1 is applied, and the film thickness of the resin layer (B) after drying becomes the thickness shown in the same table. After coating as above, it was dried at 80° C. for 30 minutes. As a result, a laminate having the resin layer (A) and the resin layer (B) in order on the first film was obtained as a dry film. However, in Comparative Example 3, a monolayer dry film having only the resin layer (A) was used. In Comparative Example 2, matte PET (PTHA-25, manufactured by Unitika Ltd., surface roughness Ra: 0.3 μm) was used as the first film, so the unevenness of the matte PET was transferred to the resin layer (A). As a result, the resin layer (A) had a physically roughened surface.

III-2. Preparation and Evaluation of Test Substrate <Preparation of Test Substrate A>
A single-sided printed wiring board having a circuit formed thereon with a copper thickness of 15 μm was prepared and pretreated using CZ8100 manufactured by MEC. A laminate was formed on a substrate by laminating the laminate (dry film) of each example and comparative example prepared above using a vacuum laminator so that the resin layer (B) was in contact with the substrate. This substrate was pattern-exposed from the resin layer (A) side using an exposure apparatus equipped with a high-pressure mercury lamp (short arc lamp) at an optimum exposure dose described later, and baked at 100° C. for 30 minutes. 1 film was peeled off. After that, development was performed for 60 seconds with a 1 wt % sodium carbonate aqueous solution at 30° C. under conditions of a spray pressure of 0.2 MPa to obtain a laminate as a solder resist pattern. This substrate is irradiated with ultraviolet rays from the resin layer (A) side in a UV conveyor furnace under the conditions of an integrated exposure amount of 1000 mJ/cm ² , and then cured by heating at 150 ° C. for 60 minutes. A test substrate A was prepared comprising:

[Determination of optimum exposure]
The optimum exposure amount used in the patterned exposure for fabricating the test substrate A was determined as follows. That is, a single-sided printed wiring board on which a circuit with a copper thickness of 15 μm is formed was prepared, and pretreatment was performed using CZ8100 manufactured by MEC. The laminate (dry film) of each example and comparative example prepared as described above is laminated using a vacuum laminator so that the resin layer (B) is in contact with the substrate, so that the laminate (optimal exposure amount A measurement sample) was formed. Each optimal exposure amount measurement sample thus obtained was exposed through a step tablet (Kodak No. 2) using an exposure apparatus equipped with a high-pressure mercury lamp. After exposure, heating was performed at 100° C. for 30 minutes. After that, the first film was peeled off, and development (30° C., 0.2 MPa, 1 wt % Na ₂ CO ₃ aqueous solution) was performed for 60 seconds. For each measurement sample, the amount of light corresponding to the density portion of the 5th stage of the step tablet in the portion remaining after development was taken as the optimum amount of exposure, and the amount of light during pattern exposure of test substrate A was determined.

<Concealability evaluation>
Using the test substrate A described above, the circuit was visually observed from a distance of 30 cm to evaluate the circuit concealability. Evaluation criteria are as follows.
⊚: The hiding power is high and the circuit cannot be visually recognized.
◯: Part of the circuit is visible.
x: The circuit can be clearly visually recognized.

<Evaluation of resistance to electroless gold plating>
Using a commercially available electroless nickel plating bath and an electroless gold plating bath, plating was performed on the test substrate A under the conditions of 0.5 μm nickel and 0.03 μm gold, and the plating surface was subjected to JIS Z 1522. A tape peeling test was performed by affixing a tape having a nominal width of 12 to 19 mm and instantaneously peeling off the tape. After the test, the presence or absence of peeling of the resist layer and the presence or absence of penetration of the plating were evaluated. Judgment criteria are as follows.
◯: Neither penetration nor peeling was observed.
×: Penetration is confirmed after plating

<Production of test substrate B>
A single-sided printed wiring board having a circuit formed thereon with a copper thickness of 15 μm was prepared and pretreated using CZ8100 manufactured by MEC. A laminate was formed on a substrate by laminating the laminate (dry film) of each example and comparative example prepared above using a vacuum laminator so that the resin layer (B) was in contact with the substrate. A negative pattern having a via opening diameter of 500 μm, 300 μm, 150 μm, 100 μm, and 80 μm was placed on the resin layer (A) of the laminated body of this substrate as a negative mask for evaluation of resolution. Using the apparatus, pattern exposure was performed at the optimum exposure dose described in connection with the preparation of test substrate A above. Furthermore, after baking at 100° C. for 30 minutes, the first film was peeled off. After that, development was performed for 60 seconds with a 1 wt % sodium carbonate aqueous solution at 30° C. and a spray pressure of 0.2 MPa to obtain a solder resist pattern. This substrate was irradiated with ultraviolet rays in a UV conveyor furnace under the condition of an integrated exposure amount of 1000 mJ/cm ² and then cured by heating at 150°C for 60 minutes to prepare a test substrate B comprising a cured product composed of each laminate. .
<Evaluation of resolution (evaluation of minimum aperture diameter))>
In the test substrate B, the pattern opening was observed with an SEM at a magnification of 200 to obtain the minimum opening diameter.

<Evaluation of Adhesion>
The cured product of the laminate of test substrate B was cut with a cutter knife so that 100 grids at 1 mm intervals were made according to the cross-cut adhesion test method based on JIS D-0202, and cellophane tape was attached. After that, the cellophane tape was peeled off, and the state of the cured product remaining on the substrate was evaluated according to the following criteria.
○: No peeling.
x: There is peeling.

<B-HAST resistance>
Test substrate B was placed in a high-temperature, high-humidity chamber under an atmosphere of 130° C. and humidity of 85%, and a voltage of 3.5 V was applied to comb-shaped electrode portions (n=6) of line/space=12 μm/13 μm. After that time, an in-tank B-HAST was performed. After 300 hours, B-HAST resistance was evaluated according to the following criteria. A resistance value of less than 1×10 ⁶ Ω was determined as a short circuit.
◎: No short-circuit occurred between all 6 comb-shaped electrodes ○: Short-circuit occurred between 1 out of 6 comb-shaped electrodes ×: Short-circuit occurred between 2 or more out of 6 comb-shaped electrodes

<Breaking strength>
The cured product of the laminate was peeled off from the test substrate B, and the peeled cured product was cut into a test piece having a width of 10 mm and a length of 70 mm according to JIS K7127, and the breaking strength was measured and evaluated. All samples had a breaking strength of 30 MPa or more.

<Heat resistance evaluation>
A rosin-based flux was applied to the test substrate B, which was then immersed in a solder bath previously set at 260° C. and 280° C. for 10 seconds to evaluate the occurrence of floating, blistering, and peeling of the cured coating film. Evaluation criteria are as follows.
⊚: No lifting, swelling or peeling occurred in both immersion at 260°C and 280°C.
◯: No lifting, swelling or peeling occurred when immersed at 260°C, but lifting, swelling or peeling occurred when immersed at 280°C.
x: Lifting and peeling occurred in both immersion at 260°C and 280°C.

The cured products of laminates according to the examples of the present invention showed good results in all evaluations. On the other hand, according to Comparative Examples 1 and 3, which have different resin compositions or layer structures, it is difficult to achieve both circuit concealability and mechanical properties. Furthermore, in Comparative Example 2, the resolution of the cured product was lowered because the circuit concealability was improved by a physical technique.

Although the invention made by the present inventors has been specifically described based on the embodiments, it should be understood that the present invention is not limited to the above-described embodiments, and that various changes can be made without departing from the gist of the invention. Needless to say.

1 first film (A) resin layer (A)
(B) Resin layer (B)
2 second film

Claims (5)

Having a resin layer (A) and a resin layer (B),
A laminate in which one surface of the resin layer (B) is in contact with one surface of the resin layer (A),
The resin layer (A) is
(A1) an alkali-soluble polyamideimide resin;
(A2) an alkali-soluble polyimide resin;
has
The resin layer (B) is
(B1) A laminate comprising an alkali-soluble (meth)acrylate resin. The (A1) alkali-soluble polyamideimide resin is represented by the following general formula (1) or (2),

(In formula (1), X1 is the residue of aliphatic diamine (a) derived from dimer acid having 24 to 48 carbon atoms, and in formula (2), X2 is the residue of aromatic diamine (b) having a carboxyl group. groups, Y are each independently a cyclohexane ring or an aromatic ring). 2. The laminate according to 1. 1. Further comprising a first film and a second film, wherein the first film, the resin layer (A), the resin layer (B) and the second film are provided in this order. 3. Or the laminated body of 2. A cured product obtained by curing the resin layer (A) and the resin layer (B) in the laminate according to claim 1 or 2. An electronic component comprising a cured product of the laminate according to claim 4.

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