JP2022058666A - Photosensitive resin composition, photosensitive element, printed wiring board, and method for manufacturing printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition that can form a permanent mask resist having excellent adhesion to an underfill, with reduced cracking, and a photosensitive element prepared therewith.

SOLUTION: A photosensitive resin composition has (A) an acid-modified vinyl group-containing epoxy resin, (B) an epoxy compound, (C) a photopolymerization initiator and (D) a photopolymerizable compound. The equivalent ratio of epoxy groups in the (B) epoxy compound to carboxyl groups in the (A) acid-modified vinyl group-containing epoxy resin is 1.2-4.0.

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a photosensitive resin composition, a photosensitive element, a printed wiring board, and a method for manufacturing a printed wiring board.

In the field of printed wiring boards, permanent mask resists are formed on printed wiring boards. The permanent mask resist has a role of preventing corrosion of the conductor layer and maintaining electrical insulation between the conductor layers when the printed wiring board is used. In recent years, permanent mask resists have prevented solder from adhering to unnecessary parts of the conductor layer of a printed wiring board even in the process of flip-chip mounting, wire bonding, etc. of semiconductor elements on a printed wiring board via solder. It also has a role as a solder resist film to prevent it.

Conventionally, a permanent mask resist has been produced by a method of screen printing using a thermosetting resin composition or a photographic method using a photosensitive resin composition. For example, in a flexible wiring board using a mounting method such as FC (Flip Chip), TAB (Tape Automated Bonding), and COF (Chip On Film), an IC chip, an electronic component, or an LCD (liquid crystal display) panel and a connection wiring pattern portion are used. The heat-curable resin paste is screen-printed and heat-cured to form a permanent mask resist (see, for example, Patent Document 1).

Further, in semiconductor package substrates such as BGA (ball grid array) and CSP (chip size package) mounted on electronic components, (1) in order to flip-chip mount semiconductor elements on the semiconductor package substrate via solder. In addition, in order to (2) wire bond the semiconductor element and the semiconductor package substrate, and (3) solder bond the semiconductor package substrate onto the motherboard substrate, it is necessary to remove the permanent mask resist at the bonded portion. be. To form an image of a permanent mask resist, a photosensitive resin composition is applied, dried, and then selectively irradiated with active light such as ultraviolet rays to cure it, and only the unirradiated portion is removed by development to form an image. Is used. Since the photographic method is suitable for mass production due to its good workability, it is widely used in the electronic materials industry for image formation of photosensitive materials. (See, for example, Patent Document 2).

Japanese Patent Application Laid-Open No. 2003-198105 Japanese Unexamined Patent Publication No. 11-240930

On the other hand, the permanent mask resist formed from the conventional photosensitive resin composition does not have sufficient adhesion to the underfill in a harsh environment such as high temperature, and cracks occur in the permanent mask resist. There is.

Therefore, an object of the present invention is a photosensitive resin composition having excellent adhesion to underfill and capable of forming a permanent mask resist with reduced generation of cracks, and a photosensitive resin composition using the photosensitive resin composition. It is an object of the present invention to provide an element, a printed wiring board, and a method for manufacturing a printed wiring board.

The first aspect of the present invention contains (A) an acid-modified vinyl group-containing epoxy resin, (B) an epoxy compound, (C) a photopolymerization initiator and (D) a photopolymerizable compound, and (A) acid-modified. The present invention relates to a photosensitive resin composition in which the equivalent ratio of the epoxy group contained in the (B) epoxy compound to the carboxyl group contained in the vinyl group-containing epoxy resin is 1.2 to 4.0.
A second aspect of the present invention relates to a photosensitive element including a support film and a photosensitive layer made of the above-mentioned photosensitive resin composition.
A third aspect of the present invention relates to a printed wiring board provided with a permanent mask resist formed of the photosensitive resin composition.
A fourth aspect of the present invention includes a step of forming a photosensitive layer on a substrate using the photosensitive resin composition or the photosensitive element, and a step of exposing and developing the photosensitive layer to form a resist pattern. The present invention relates to a method for manufacturing a printed wiring board, which comprises a step of curing the resist pattern to form a permanent mask resist.

According to the present invention, a photosensitive resin composition having excellent adhesion to underfill and capable of forming a permanent mask resist with reduced crack generation, a photosensitive element using the same, a printed wiring board and a printed circuit board. A method for manufacturing a wiring board can be provided.

It is sectional drawing which shows typically the photosensitive element of this embodiment.

Hereinafter, one embodiment of the present invention will be specifically described, but the present invention is not limited thereto. Needless to say, in the following embodiments, the components (including element steps and the like) are not necessarily essential unless otherwise specified or clearly considered to be essential in principle. This also applies to numerical values and ranges, and should be construed as not unreasonably limiting the present invention.

In addition, in this specification, the term "layer" includes not only the structure having a shape formed on the entire surface but also the structure having a shape partially formed when observed as a plan view. In the present specification, the term "process" is used not only as an independent process but also as a term as long as the intended purpose of the process is achieved even if it cannot be clearly distinguished from other processes. included. In the present specification, the numerical range indicated by using "-" indicates a range including the numerical values before and after "-" as the minimum value and the maximum value, respectively. In the numerical range described stepwise in the present specification, the upper limit value or the lower limit value of the numerical range of one step may be replaced with the upper limit value or the lower limit value of the numerical range of another step. Further, in the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. "A or B" may include either A or B, and may include both. Unless otherwise specified, the materials exemplified below may be used alone or in admixture of two or more. The content of each component in the composition means the total amount of the plurality of substances present in the composition when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified.

[Photosensitive resin composition]
The photosensitive resin composition of the present embodiment is referred to as (A) acid-modified vinyl group-containing epoxy resin (hereinafter, may be referred to as (A) component), (B) epoxy compound (hereinafter, referred to as (B) component). (C), (C) photopolymerization initiator (hereinafter, may be referred to as (C) component) and (D) photopolymerizable compound (hereinafter, may be referred to as (D) component). The equivalent ratio of the epoxy group contained in the (B) epoxy compound to the carboxyl group contained in the (A) acid-modified vinyl group-containing epoxy resin is 1.2 to 4.0.

The photosensitive resin composition has excellent adhesion to underfill and can form a permanent mask resist in which the occurrence of cracks is reduced. In addition, the photosensitive resin composition can form a permanent mask resist having excellent fluidity and adhesion to a copper substrate. Further, the photosensitive resin composition has resolution, electrical insulation, solder heat resistance, heat impact resistance, solvent resistance, acid resistance and alkali resistance required for the photosensitive resin composition used for manufacturing printed wiring boards. It is also excellent in performance.

<(A) Acid-modified vinyl group-containing epoxy resin>
The component (A) is a resin obtained by acid-modifying a reaction product of an epoxy resin and an organic acid having a vinyl group, and is a resin containing a vinyl group and a carboxyl group. As the component (A), for example, an addition reaction product obtained by adding a saturated or unsaturated polybasic acid anhydride to an esterified product obtained by reacting an epoxy resin with a vinyl group-containing monocarboxylic acid can be used.

As the component (A), for example, an acid-modified vinyl group-containing epoxy resin (A1) obtained by using a bisphenol novolak type epoxy resin (a1) (hereinafter, may be referred to as an epoxy resin (a1)) as an epoxy resin. ) (Hereinafter, it may be referred to as a component (A1)), acid modification obtained by using an epoxy resin (a2) other than the epoxy resin (a1) (hereinafter, may be referred to as an epoxy resin (a2)). Examples thereof include a vinyl group-containing epoxy resin (A2) (hereinafter, may be referred to as a component (A2)). These can be used alone or in combination of two or more.

(Epoxy resin (a1))
Examples of the epoxy resin (a1) include an epoxy resin having a structural unit represented by the following general formula (I) or (II), and an epoxy resin having a structural unit represented by the general formula (II) can be used. preferable.

In formula (I), R ¹¹ represents a hydrogen atom or a methyl group, and a plurality of R ¹¹ may be the same or different. Y ¹ and Y ² each independently represent a hydrogen atom or a glycidyl group, but at least one of Y ¹ and Y ² is a glycidyl group.

From the viewpoint of improving the resolution, R ¹¹ is preferably a hydrogen atom, and Y ¹ and Y ² are preferably glycidyl groups.

The number of structural units represented by the general formula (I) in the epoxy resin (a1) is 1 or more, and may be 10 to 100, 15 to 80, or 15 to 70. When the number of structural units is within the above range, it becomes easy to improve the adhesion to the underfill, the heat resistance, and the electrical insulation. Here, the number of structural units of the structural unit indicates an integer value in a single molecule and a rational number which is an average value in an aggregate of a plurality of types of molecules. Hereinafter, the same applies to the number of structural units.

In formula (II), R ¹² represents a hydrogen atom or a methyl group, and a plurality of R ^12s may be the same or different. Y ³ and Y ⁴ each independently represent a hydrogen atom or a glycidyl group, but at least one of Y ³ and Y ⁴ is a glycidyl group.

From the viewpoint of improving the resolution, R ¹² is preferably a hydrogen atom, and Y ³ and Y ⁴ are preferably glycidyl groups.

The number of structural units represented by the general formula (II) in the epoxy resin (a1) is 1 or more, and may be 10 to 100, 15 to 80, or 15 to 70. When the number of structural units is within the above range, it becomes easy to improve the adhesion to the underfill, the heat resistance, and the electrical insulation.

In the general formula (II), the epoxy resin in which R ¹² is a hydrogen atom and Y ³ and Y ⁴ are glycidyl groups is used as EXA-7376 series (manufactured by DIC Co., Ltd., trade name), and R ¹² is used. Epoxy resins that are methyl groups and have glycidyl groups ^Y3 and Y4 ^are commercially available as EPON SU8 Series (manufactured by Japan Epoxy Resin Co., Ltd., trade name).

(Epoxy resin (a2))
The epoxy resin (a2) is not particularly limited as long as it is an epoxy resin different from the epoxy resin (a1), but from the viewpoint of improving the adhesion to the underfill, a novolak type epoxy resin, a bisphenol A type epoxy resin, and a bisphenol. It is preferably at least one selected from the group consisting of an F-type epoxy resin and a triphenol methane-type epoxy resin.

Examples of the novolak type epoxy resin include epoxy resins having a structural unit represented by the following general formula (III). Examples of the bisphenol A type epoxy resin or the bisphenol F type epoxy resin include epoxy resins having a structural unit represented by the following general formula (IV). Examples of the triphenol methane type epoxy resin include epoxy resins having a structural unit represented by the following general formula (V).

The epoxy resin (a2) may be at least one selected from a novolak type epoxy resin having a structural unit represented by the general formula (III) and an epoxy resin having a structural unit represented by the general formula (IV). More preferred. The epoxy resin having the structural unit represented by the general formula (IV) is preferably a bisphenol F type epoxy resin.

As the epoxy resin (a2), a novolak type epoxy resin having a structural unit represented by the following general formula (III) is preferable. Examples of the novolak type epoxy resin having such a structural unit include a novolak type epoxy resin represented by the following general formula (III').

In formulas (III) and (III'), R ¹³ represents a hydrogen atom or a methyl group, Y ⁵ represents a hydrogen atom or a glycidyl group, but at least one of Y ⁵ is a glycidyl group. In formula (III'), n ₁ is a number of 1 or more, and a plurality of R ¹³ and Y ⁵ may be the same or different.

From the viewpoint of improving the resolution, R ¹³ is preferably a hydrogen atom. In the general formula (III'), the molar ratio of Y ⁵ which is a hydrogen atom and Y ⁵ which is a glycidyl group is 0/100 to 30/70 or 0/100 to 10 / from the viewpoint of improving the resolution. It may be 90. As can be seen from this molar ratio, at ^least one of Y5 is a glycidyl group.

n ₁ is 1 or more, but may be 10 to 200, 30 to 150, or 30 to 100. When n ₁ is within the above range, the adhesion to the underfill, heat resistance, and electrical insulation are likely to be improved.

Examples of the novolak type epoxy resin represented by the general formula (III') include phenol novolac type epoxy resin and cresol novolak type epoxy resin. These novolak-type epoxy resins can be obtained, for example, by reacting a phenol novolak resin or a cresol novolak resin with epichlorohydrin by a known method.

Examples of the phenol novolac type epoxy resin or cresol novolac type epoxy resin represented by the general formula (III') include YDCN-701, YDCN-702, YDCN-703, YDCN-704, YDCN-704L, YDPN-638. YDPN-602 (above, manufactured by Nippon Steel Chemical Co., Ltd., trade name), DEN-431, DEN-439 (above, manufactured by Dow Chemical Co., Ltd., trade name), EOCN-120, EOCN-102S, EOCN- 103S, EOCN-1012S, EOCN-1012, EOCN-1025, EOCN-1027, BREN (above, manufactured by Nippon Kayaku Co., Ltd., trade name), EPN-1138, EPN-1235, EPN-1299 (above, BASF) (Product name), N-730, N-770, N-865, N-665, N-673, VH-4150, VH-4240 (above, product name manufactured by DIC Co., Ltd.), etc. are commercially available. It is available.

As the epoxy resin (a2), a bisphenol A type epoxy resin or a bisphenol F type epoxy resin having a structural unit represented by the following general formula (IV) is preferably mentioned. Examples of the epoxy resin having such a structural unit include a bisphenol A type epoxy resin represented by the general formula (IV') or a bisphenol F type epoxy resin.

In formulas (IV) and (IV'), R ¹⁴ represents a hydrogen atom or a methyl group, and a plurality of R ¹⁴ may be the same or different, and Y ⁶ represents a hydrogen atom or a glycidyl group. In formula (IV'), n ₂ represents a number of 1 or more, and when n ₂ is 2 or more, the plurality of Y ^6s may be the same or different, and at least one Y ⁶ is a glycidyl group.

From the viewpoint of improving the resolution, R ¹⁴ is preferably a hydrogen atom, and Y ⁶ is preferably a glycidyl group.

n ₂ indicates 1 or more, but may be 10 to 100, 10 to 80, or 15 to 60. When n ₂ is within the above range, the adhesion to the underfill, heat resistance, and electrical insulation are likely to be improved.

The bisphenol A type epoxy resin or bisphenol F type epoxy resin in which Y ⁶ in the general formula (IV) is a glycidyl group is, for example, a bisphenol A type epoxy resin or bisphenol in which Y ⁶ in the general formula (IV) is a hydrogen atom. It can be obtained by reacting a hydroxyl group (-OY ⁶ ) of an F-type epoxy resin with epichlorohydrin.

In order to promote the reaction between the hydroxyl group and epichlorohydrin, it is preferable to carry out the reaction at a reaction temperature of 50 to 120 ° C. in the presence of an alkali metal hydroxide in a polar organic solvent such as dimethylformamide, dimethylacetamide or dimethyl sulfoxide. When the reaction temperature is within the above range, the reaction does not become too slow and side reactions can be suppressed.

Examples of the bisphenol A type epoxy resin or the bisphenol F type epoxy resin represented by the general formula (IV') include Epicoat 807, 815, 825, 827, 828, 834, 1001, 1004, 1007 and 1009 (all of which are Japan). Epoxy Resin Co., Ltd., trade name), DER-330, DER-301, DER-361 (above, Dow Chemical Co., Ltd., trade name), YD-8125, YDF-170, YDF-170, YDF- 175S, YDF-2001, YDF-2004, YDF-8170 (all manufactured by Nippon Steel Chemical Co., Ltd., trade name) and the like are commercially available.

As the epoxy resin (a2), a triphenol methane type epoxy resin having a structural unit represented by the following general formula (V) is preferably mentioned. Examples of the triphenol methane type epoxy resin having such a structural unit include a triphenol methane type epoxy resin represented by the general formula (V').

In formulas (V) and (V'), Y ⁷ represents a hydrogen atom or a glycidyl group, and a plurality of Y ^7s may be the same or different, and at least one Y ⁷ is a glycidyl group. In the formula (V'), n ₃ represents a number of 1 or more.

From the viewpoint of improving the resolution, the molar ratio of Y ⁷ which is a hydrogen atom and Y ⁷ which is a glycidyl group in Y ⁷ may be 0/100 to 30/70. As can be seen from this molar ratio, at least one of ^Y7 is a glycidyl group.

n ₃ is 1 or more, but may be 10 to 100, 15 to 80, or 15 to 70. When n ₃ is within the above range, the adhesion to the underfill, heat resistance, and electrical insulation are likely to be improved.

As the triphenol methane type epoxy resin represented by the general formula (V'), for example, FAE-2500, EPPN-501H, EPPN-502H (all manufactured by Nippon Kayaku Co., Ltd., trade name) and the like are commercially available. It is available at.

The components (A1) and (A2) are referred to as an epoxy resin (a1) and an epoxy resin (a2) (hereinafter, may be collectively referred to as "component (a)") from the viewpoint of improving resolution. , A vinyl group-containing monocarboxylic acid (b) (hereinafter, may be referred to as a component (b)) and an esterified product (A1') and (A2') (hereinafter collectively referred to as "(A)". It is preferably an addition reaction product obtained by adding a saturated or unsaturated polybasic acid anhydride (c) (hereinafter, may be referred to as a component (c)) to a) component. ..

(Vinyl group-containing monocarboxylic acid (b))
Examples of the component (b) include acrylic acid, a dimer of acrylic acid, methacrylic acid, β-fulfurylacrylic acid, β-styrylacrylic acid, cinnamic acid, crotonic acid, and acrylic acid such as α-cyanoceramic acid. A semi-ester compound which is a reaction product of a derivative, a hydroxyl group-containing acrylate and a dibasic acid anhydride, a vinyl group-containing monoglycidyl ether or a semi-ester which is a reaction product of a vinyl group-containing monoglycidyl ester and a dibasic acid anhydride. Examples include compounds.

The semi-ester compound can be obtained, for example, by reacting a hydroxyl group-containing acrylate, a vinyl group-containing monoglycidyl ether or a vinyl group-containing monoglycidyl ester with a dibasic acid anhydride in an equimolar ratio. The component (b) can be used alone or in combination of two or more.

Examples of the hydroxyl group-containing acrylate, vinyl group-containing monoglycidyl ether and vinyl group-containing monoglycidyl ester include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate and polyethylene glycol monoacrylate. , Polyethylene Glycol Monomethacrylate, Trimethylol Propane Diacrylate, Trimethylol Propane Dimethacrylate, Pentaerythritol Triacrylate, Pentaerythritol Trimethacrylate, Dipentaerythritol Pentaacrylate, Pentaerythritol Pentamethacrylate, Glysidylacrylate and Glysidyl Methacrylate.

Examples of the dibasic acid anhydride include succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, ethyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride. , Ethylhexahydrophthalic anhydride and phthalic anhydride.

In the reaction between the component (a) and the component (b), it is preferable to react the component (b) at a ratio of 0.6 to 1.05 equivalent to 1 equivalent of the epoxy group of the component (a). , It is more preferable to react at a ratio of 0.8 to 1.0 equivalent. By reacting at such a ratio, the photopolymerizability is improved, that is, the photosensitivity is increased, so that the resolution is improved.

The component (a) and the component (b) can be dissolved in an organic solvent and reacted. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether and dipropylene glycol. Glycol ethers such as monoethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, carbitol acetate; aliphatic hydrocarbons such as octane and decane; petroleum Examples thereof include petroleum-based solvents such as ether, petroleum naphtha, hydrocarbon petroleum naphtha, and solvent naphtha.

A catalyst may be used to promote the reaction between the component (a) and the component (b). Examples of the catalyst include triethylamine, benzylmethylamine, methyltriethylammonium chloride, benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, benzyltrimethylammonium iodide and triphenylphosphine.
From the viewpoint of promoting the reaction between the component (a) and the component (b), the amount of the catalyst used is 0.01 to 10 parts by mass with respect to 100 parts by mass in total of the component (a) and the component (b). , 0.05 to 2 parts by mass or 0.1 to 1 part by mass.

It is preferable to use a polymerization inhibitor for the purpose of preventing polymerization during the reaction. Examples of the polymerization inhibitor include hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, catechol, pyrogallol and the like. From the viewpoint of improving the storage stability of the composition, the amount of the polymerization inhibitor used is 0.01 to 1 part by mass, 0.02 with respect to 100 parts by mass in total of the component (a) and the component (b). It may be up to 0.8 parts by mass or 0.04 to 0.5 parts by mass.

The reaction temperature between the component (a) and the component (b) may be 60 to 150 ° C., 80 to 120 ° C. or 90 to 110 ° C. from the viewpoint of productivity.

The component (A') formed by reacting the component (a) and the component (b) has a hydroxyl group formed by a cycloaddition reaction between the epoxy group of the component (a) and the carboxyl group of the component (b). It is presumed that it is doing. Further, by further reacting the component (A') with the component (c), the hydroxyl group of the component (A') (including the hydroxyl group originally present in the component (a)) and the acid anhydride of the component (c). It is presumed that the acid-modified vinyl group-containing epoxy resin is semi-esterified with the physical group.

(Polybasic acid anhydride (c))
Examples of the component (c) include succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, ethyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride. Ethylhexahydrophthalic anhydride and thalic anhydride can be mentioned. Among these, tetrahydrophthalic anhydride is preferable from the viewpoint of obtaining a photosensitive resin composition capable of forming a pattern having excellent resolution.

The reaction temperature between the component (A') and the component (c) may be 50 to 150 ° C., 60 to 120 ° C. or 70 to 100 ° C. from the viewpoint of productivity.

If necessary, as the component (a), for example, a hydrogenated bisphenol A type epoxy resin may be used in combination, and styrene-maleic acid such as a hydroxyethyl (meth) acrylate-modified product of a styrene-maleic anhydride copolymer may be used in combination. A system resin may be used in combination.

In the reaction between the component (A') and the component (c), for example, by reacting the component (c) by 0.1 to 1.0 equivalent with respect to 1 equivalent of the hydroxyl group in the component (A'), ( A) The acid value of the component can be adjusted.

The acid value of the component (A) may be 30 to 150 mgKOH / g, 40 to 120 mgKOH / g or 50 to 100 mgKOH / g. When the acid value is 30 mgKOH / g or more, the solubility of the photosensitive resin composition in a dilute alkaline solution is excellent, and when the acid value is 150 mgKOH / g or less, the electrical characteristics of the permanent mask resist are improved.

The weight average molecular weight (Mw) of the component (A) may be 3000 to 30000, 4000 to 25000 or 5000 to 18000. Within the above range, a resist having excellent resolution can be formed, and adhesion to the underfill, heat resistance and electrical insulation can be further improved. Here, Mw is a value measured by a gel permeation chromatography (GPC) method and converted into standard polystyrene. Mw can be, for example, a value measured under the following GPC conditions and converted using a standard polystyrene calibration curve as Mw. A 5-sample set (“PStQuick MP-H” and “PStQuick B”, manufactured by Tosoh Corporation) can be used as the standard polystyrene for preparing the calibration curve.
(GPC condition)
GPC device: High-speed GPC device "HCL-8320GPC",
Detector: Differential refractometer or UV, Column manufactured by Tosoh Corporation: Column TSKgel SuperMultipore HZ-H (column length: 15 cm, column inner diameter: 4.6 mm), eluent manufactured by Tosoh Corporation: tetrahydrofuran (THF)
Measurement temperature: 40 ° C
Flow rate: 0.35 mL / min Sample concentration: 10 mg / THF 5 mL
Injection volume: 20 μL

The content of the component (A) is 20 to 80% by mass and 30 to 70 based on the total solid content of the photosensitive resin composition from the viewpoint of improving the heat resistance, electrical characteristics and chemical resistance of the permanent mask resist. It may be% by mass or 30 to 50% by mass. In the present specification, the "solid content" is a non-volatile substance excluding volatile substances such as water and a diluent contained in the photosensitive resin composition, and evaporates when the resin composition is dried. Alternatively, it indicates a component that remains without volatilizing, and also contains a liquid, water candy-like or wax-like component at room temperature around 25 ° C.

When the component (A1) and the component (A2) are used in combination as the component (A), the total content of the component (A1) and the component (A2) in the component (A) improves the solder heat resistance. From the viewpoint, it may be 80 to 100% by mass, 90 to 100% by mass, 95 to 100% by mass or 100% by mass. Further, when the component (A1) or the component (A2) is used alone, it can be appropriately selected from the above range.

When the component (A1) and the component (A2) are used in combination as the component (A), the mass ratio (A1 / A2) is 20/80 to 90/10, 20 from the viewpoint of improving the solder heat resistance. It may be / 80 to 80/20 or 30/70 to 70/30.

<(B) Epoxy compound>
As the epoxy compound as the component (B), a compound having two or more epoxy groups can be used, and examples thereof include a carboxy group contained in the component (A) and an epoxy compound that is cured by heat or ultraviolet rays. By using the component (B), a permanent mask resist having excellent heat resistance, adhesion and chemical resistance can be formed.

Examples of the epoxy compound include bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, novolak type epoxy resin, bisphenol S type epoxy resin, and biphenyl type epoxy resin. , Triglycidyl isocyanurate and other heterocyclic epoxy resins and bixilenol type epoxy resins.

From the viewpoint of improving the adhesion to the underfill, the equivalent ratio of the epoxy group contained in the component (B) to the carboxyl group contained in the component (A) is 1.2 to 4.0, but 1. 3 to 3.8 is preferable, and 1.5 to 3.5 is more preferable. That is, the content of the component (B) in the photosensitive resin composition is 1.2 to 4.0 equivalents of the epoxy group contained in the component (B) with respect to 1 equivalent of the carboxyl group contained in the component (A). However, it is preferably 1.3 to 3.8 equivalents, and more preferably 1.5 to 3.5 equivalents.

<(C) Photopolymerization Initiator>
The photopolymerization initiator as the component (C) is not particularly limited as long as the photopolymerizable compound as the component (D) can be polymerized. Examples of the component (C) include an alkylphenone-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, a compound having a thioxanthone skeleton, and a titanosen-based photopolymerization initiator. Among these, an alkylphenone-based photopolymerization initiator or an acylphosphine oxide-based photopolymerization initiator is preferable from the viewpoint of improving solder heat resistance. The component (C) can be used alone or in combination of two or more.

Examples of the alkylphenone-based photopolymerization initiator include benzophenone, N, N'-tetraalkyl-4,4'-diaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-. 1,2-Methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanol, 4,4'-bis (dimethylamino) benzophenone (Mihilerketone), 4,4'-bis (diethylamino) benzophenone And 4-methoxy-4'-dimethylaminobenzophenone.

Examples of the acylphosphine oxide-based photopolymerization initiator include (2,6-dimethoxybenzoyl) -2,4,4-pentylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl-2,4. 6-trimethylbenzoylphenylphosphinate, bis (2,4,6-trimethylbenzoyl) -phenylphosphinoxide, (2,5-dihydroxyphenyl) diphenylphosphine oxide, (p-hydroxyphenyl) diphenylphosphinoxide, bis (p) -Hydroxyphenyl) phenylphosphine oxide, and tris (p-hydroxyphenyl) phosphine oxide and bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide.

The content of the component (C) may be 0.2 to 15% by mass, 0.4 to 5% by mass or 0.6 to 1% by mass based on the total solid content of the photosensitive resin composition. .. When the content of the component (C) is 0.2% by mass or more, it becomes difficult for the exposed portion to elute during development, and when it is 15% by mass or less, it becomes easy to suppress the decrease in heat resistance.

<(D) Photopolymerizable compound>
The photopolymerizable compound as the component (D) is not particularly limited as long as it is a compound having a functional group exhibiting photopolymerizability. Examples of the functional group exhibiting photopolymerizability include ethylenically unsaturated groups such as vinyl group, allyl group, propagyl group, butenyl group, ethynyl group, phenylethynyl group, maleimide group, nadiimide group and (meth) acryloyl group. Can be mentioned. From the viewpoint of reactivity, the component (D) preferably contains a compound having a (meth) acryloyl group.

As the component (D), for example, hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; glycol mono such as ethylene glycol, methoxytetraethylene glycol and polyethylene glycol. Or di (meth) acrylate; (meth) acrylamide compound such as N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide; aminoalkyl (meth) such as N, N-dimethylaminoethyl (meth) acrylate. Acrylate; Polyhydric alcohols such as hexanediol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, tris-hydroxyethyl isocyanurate or polyvalent (meth) acrylates of these ethylene oxide or propylene oxide adducts; phenoxy. Ethylene oxide of phenol compounds such as ethyl (meth) acrylate and polyethoxydi (meth) acrylate of bisphenol A or (meth) acrylate compounds of propylene oxide adduct; Examples thereof include (meth) acrylates and melamine (meth) acrylates of glycidyl ethers. These components (D) can be used alone or in combination of two or more.

The content of the component (D) may be 0.1 to 5% by mass, 0.1 to 3% by mass or 0.5 to 2% by mass based on the total solid content in the photosensitive resin composition. good. When it is 2% by mass or more, it is possible to suppress elution of the exposed portion during development, and when it is 50% by mass or less, it is possible to suppress a decrease in heat resistance.

<(E) Pigment>
The photosensitive resin composition of the present embodiment may further contain a pigment as the component (E). As the component (E), a colorant that develops a desired color when concealing the wiring or the like can be used. Examples of the component (E) include known colorants such as phthalocyanine blue, phthalocyanine green, iodin green, diazo yellow, crystal violet, titanium oxide, carbon black, and naphthalene black.

The content of the component (E) is 2 to 30% by mass, 3 to 20% by mass, or 3 to 10% by mass based on the total amount of solid content in the photosensitive resin composition from the viewpoint of further concealing the wiring. You may.

<(F) Inorganic filler>
The photosensitive resin composition of the present embodiment may further contain an inorganic filler as the component (F) for the purpose of improving properties such as adhesion and hardness of the permanent mask resist. Examples of the component (F) include silica, alumina, zirconia), talc, aluminum hydroxide), calcium carbonate, barium sulfate, calcium sulfate, zinc oxide, magnesium titanate and carbon. The component (F) can be used alone or in combination of two or more.

The component (F) may contain silica from the viewpoint of improving heat resistance, and exhibits solder heat resistance, crack resistance (heat impact resistance), and adhesive strength between the underfill material and the permanent mask resist after the PCT test. From the viewpoint of improvement, barium sulfate may be contained, or silica and barium sulfate may be contained in combination. Further, the component (F) may contain an inorganic filler surface-treated with alumina or an organic silane compound from the viewpoint of improving the antiaggregation effect.

The average particle size of the component (F) may be 0.1 to 20 μm, 0.1 to 10 μm, 0.1 to 5 μm, or 0.1 to 1 μm. When the average particle size is 20 μm or less, the deterioration of the insulation reliability of the permanent mask resist can be further suppressed.

The content of the component (F) may be 10 to 80% by mass, 15 to 70% by mass, or 20 to 50% by mass based on the total solid content of the photosensitive resin composition. Within the above range, the resolution of the photosensitive resin composition can be improved, and the strength, heat resistance, insulation reliability and heat impact resistance of the permanent mask resist can be further improved.

When silica is used as the component (F), the content of silica may be 5 to 60% by mass, 15 to 55% by mass, or 15 to 50% by mass based on the total solid content of the photosensitive resin composition. good. When barium sulfate is used as the component (F), the content of barium sulfate is 5 to 30% by mass, 5 to 25% by mass, or 5 to 20% by mass based on the total solid content of the photosensitive resin composition. May be%. Within the above range, the solder heat resistance and the adhesive strength between the underfill material and the cured film after the PCT resistance test can be further improved.

<(G) Hardener>
The photosensitive resin composition of the present embodiment may further contain a curing agent as the component (G). The component (G) includes a compound that is itself cured by heat, ultraviolet rays, or the like, or the carboxy group or hydroxyl group of the component (A) that is a photocurable component in the photosensitive resin composition of the present embodiment, and heat. , Compounds that cure with ultraviolet rays and the like can be mentioned. By using a curing agent, the heat resistance, adhesion, chemical resistance, etc. of the permanent mask resist can be improved.

Examples of the component (G) include thermosetting compounds such as melamine compounds and oxazoline compounds. Examples of the melamine compound include triaminotriazine, hexamethoxymelamine and hexabutoxyd melamine. The component (G) can be used alone or in combination of two or more.

When the component (G) is used, the content thereof may be 2 to 40% by mass, 3 to 30% by mass, or 5 to 20% by mass based on the total solid content of the photosensitive resin composition. By keeping it within the above range, the heat resistance of the formed permanent mask resist can be further improved while maintaining good developability.

In the photosensitive resin composition of the present embodiment, a curing accelerator for accelerating the curing of the component (D) is added for the purpose of further improving the properties such as heat resistance, adhesion, and chemical resistance of the permanent mask resist. It may be used together.

Examples of the curing accelerator include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole and the like. Imidazole derivatives of imidazole; guanamines such as acetoguanamine and benzoguanamine; polyamines such as diaminodiphenylmethane, m-phenylenediamine, m-xylenediamine, diaminodiphenylsulphon, dicyandiamide, urea, urea derivatives, melamine and polybasic hydrazide; these organic acids Examples thereof include salts or epoxyadducts; amine complexes of boron trifluoride; triazine derivatives such as ethyldiamino-S-triazine, 2,4-diamino-S-triazine, 2,4-diamino-6-xysilyl-S-triazine. .. The curing accelerator can be used alone or in combination of two or more.

The content of the curing accelerator in the photosensitive resin composition is 0.01 to 20% by mass or 0.1 to 10% by mass based on the total solid content of the photosensitive resin composition from the viewpoint of improving reliability. May be.

<(H) Elastomer>
The photosensitive resin composition of the present embodiment may further contain an elastomer as the component (H). The component (H) can be suitably used particularly when the photosensitive resin composition of the present embodiment is used for a semiconductor package substrate. By adding the component (H) to the photosensitive resin composition, it is possible to suppress a decrease in flexibility and adhesive strength due to the strain (internal stress) inside the resin due to the curing shrinkage of the component (A). That is, the flexibility and adhesive strength of the permanent mask resist formed by the photosensitive resin composition can be improved.

Examples of the component (H) include thermoplastic elastomers such as styrene-based elastomers, olefin-based elastomers, urethane-based elastomers, polyester-based elastomers, polyamide-based elastomers, acrylic-based elastomers, and silicone-based elastomers. The thermoplastic elastomer is composed of a hard segment component that contributes to heat resistance and strength, and a soft segment component that contributes to flexibility and toughness. The component (H) can be used alone or in combination of two or more.

As the urethane-based elastomer, a compound composed of a hard segment composed of a small molecule (short chain) diol and a diisocyanate and a soft segment composed of a high molecular weight (long chain) diol and a diisocyanate can be used. Examples of small molecule diols include ethylene glycol, propylene glycol, 1,4-butanediol and bisphenol A. Examples of the polymer diol include polypropylene glycol, polytetramethylene oxide, poly (1,4-butylene adipate), poly (ethylene-1,4-butylene adipate), polycaprolactone, and poly (1,6-hexylene carbonate). And poly (1,6-hexylene-neopentylene adipate).

The number average molecular weight (Mn) of the small molecule diol is preferably 48 to 500. The Mn of the polymer diol is preferably 500 to 10000. As the urethane elastomer, PANDEX T-2185, T-2983N (manufactured by DIC Corporation), Miractran E790 (manufactured by Nippon Miractran Co., Ltd.) and the like are commercially available.

As the polyester-based elastomer, a compound obtained by polycondensing a dicarboxylic acid or a derivative thereof and a diol compound or a derivative thereof can be used. Examples of the dicarboxylic acid include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and aromatic dicarboxylic acids in which the hydrogen atom of these aromatic nuclei is substituted with a methyl group, an ethyl group, a phenyl group, or the like; adipic acid. , An aliphatic dicarboxylic acid having 2 to 20 carbon atoms such as sebacic acid and dodecanedicarboxylic acid; and an alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid.

Examples of the diol compound include aliphatic diols or fats such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,10-decanediol, and 1,4-cyclohexanediol. Examples thereof include cyclic diols and divalent phenols represented by the following general formula (VI).

In the formula (VI), Y represents an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 4 to 8 carbon atoms, an ether group, a thioether group, a sulfonyl group or a single bond, and R ¹ and R ² are independent of each other. , Hydrogen atom, halogen atom or alkyl group having 1 to 12 carbon atoms, l and m are independently integers of 0 to 4, and p is 0 or 1. The alkylene group and the cycloalkylene group may be linear or branched, and may be substituted with a halogen atom, an alkyl group, an aryl group, an aralkyl group, an amino group, an amide group, an alkoxy group or the like.

Examples of the dihydric phenol represented by the general formula (VI) include bisphenol A, bis- (4-hydroxyphenyl) methane, bis- (4-hydroxy-3-methylphenyl) propane and resorcin. These compounds can be used alone or in combination of two or more.

As the polyester-based elastomer, a multi-block copolymer having an aromatic polyester (for example, polybutylene terephthalate) as a hard segment component and an aliphatic polyester (for example, polytetramethylene glycol) portion as a soft segment component can be used. There are various grades of polyester elastomers depending on the type, ratio, and molecular weight of the hard segment and the soft segment. As polyester elastomers, Hytrel (Dupont-Toray Industries, Inc., "Hytrel" is a registered trademark), Perprene (Toyobo Co., Ltd., "Perprene" is a registered trademark), Esper (Hitachi Kasei Co., Ltd., "" "Esper" is a registered trademark) and is commercially available.

As the acrylic elastomer, a compound containing a structural unit based on an acrylic acid ester as a main component can be used. Examples of the acrylic acid ester include ethyl acrylate, butyl acrylate, methoxyethyl acrylate and ethoxyethyl acrylate. The acrylic elastomer may be a compound obtained by copolymerizing an acrylic acid ester with acrylonitrile, or may be a compound further copolymerized with a monomer having a functional group as a cross-linking point. Examples of the monomer having a functional group include glycidyl methacrylate and allyl glycidyl ether. Examples of the acrylic elastomer include acrylonitrile-butyl acrylate copolymer, acrylonitrile-butyl acrylate-ethyl acrylate copolymer and acrylonitrile-butyl acrylate-glycidyl methacrylate copolymer.

A rubber-modified epoxy resin may be used as the elastomer other than the thermoplastic elastomer. The rubber-modified epoxy resin is, for example, a part or all of the epoxy groups of the above-mentioned bisphenol F type epoxy resin, bisphenol A type epoxy resin, salicylaldehyde type epoxy resin, phenol novolac type epoxy resin or cresol novolac type epoxy resin. , Both-terminal carboxylic acid-modified butadiene-acrylonitrile rubber, terminal amino-modified silicone rubber, etc. Among these elastomers, Esper (manufactured by Hitachi Chemical Co., Ltd., Esper 1612, 1620), which is a double-ended carboxyl group-modified butadiene-acrylonitrile copolymer and a polyester elastomer having a hydroxyl group, is preferable from the viewpoint of shear adhesion. ..

The content of the component (H) may be 2 to 40 parts by mass, 4 to 30 parts by mass, 10 to 25 parts by mass, or 15 to 22 parts by mass with respect to 100 parts by mass of the component (A). Within the above range, the unexposed portion of the photosensitive layer is more likely to elute with the developing solution, and the elastic modulus of the permanent mask resist in the high temperature region becomes lower.

<Other ingredients>
If necessary, the photosensitive resin composition of the present embodiment may be mixed with a diluent such as an organic solvent in order to adjust the viscosity. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene, methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether and dipropylene glycol. Glycol ethers such as monoethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether, esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate and carbitol acetate, aliphatic hydrocarbons such as octane and decane, petroleum Examples thereof include petroleum-based solvents such as ether, petroleum naphtha, hydrocarbon petroleum naphtha, and solvent naphtha.

When a diluent is used, the content of the diluent in the photosensitive resin composition may be 10 to 50% by mass, 20 to 40% by mass, or 25 to 35% by mass. Within the above range, the coatability of the photosensitive resin composition is improved, and a higher-definition pattern can be formed.

Various additives may be further mixed with the photosensitive resin composition of the present embodiment, if necessary. Examples of the additive include polymerization inhibitors such as hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, catechol, and pyrogallol; thickeners such as Benton and montmorillonite; silicone-based, fluorine-based or vinyl resin-based defoaming agents; silane cups. Ring agents; flame retardants such as brominated epoxy compounds, acid-modified brominated epoxy compounds, antimony compounds, phosphate compounds of phosphorus compounds, aromatic condensed phosphoric acid esters, halogen-containing condensed phosphoric acid esters and the like can be mentioned.

The photosensitive resin composition of the present embodiment can be prepared by uniformly mixing each of the above-mentioned components with a roll mill, a bead mill, or the like.

[Photosensitive element]
The photosensitive element of the present embodiment includes a support film and a photosensitive layer made of the photosensitive resin composition of the present embodiment. FIG. 1 is a cross-sectional view schematically showing a photosensitive element of the present embodiment. As shown in FIG. 1, the photosensitive element 1 includes a support film 10 and a photosensitive layer 20 formed on the support film 10. Further, a protective film 30 for covering the photosensitive layer 20 may be further provided on the photosensitive layer 20.

The photosensitive element 1 of the present embodiment is, for example, after the photosensitive resin composition of the present embodiment is applied onto the support film 10 by a known method such as a reverse roll coat, a gravure roll coat, a comma coat, and a curtain coat. It can be produced by drying the coating film to form the photosensitive layer 20.

Examples of the support film include polyester films such as polyethylene terephthalate and polybutylene terephthalate, and polyolefin films such as polypropylene and polyethylene. The thickness of the support film is, for example, 5 to 100 μm. The thickness of the photosensitive layer may be 10 to 50 μm, 15 to 40 μm, or 20 to 30 μm.

As the coating film is dried, hot air drying, drying using far infrared rays or near infrared rays can be used, and the drying temperature may be 60 to 120 ° C., 70 to 110 ° C. or 80 to 100 ° C. The drying time may be 1 to 60 minutes, 2 to 30 minutes, or 5 to 20 minutes.

In the photosensitive element 1 of the present embodiment, the protective film 30 can be laminated on the surface of the photosensitive layer 20 opposite to the surface in contact with the support film 10. As the protective film, for example, a polymer film such as polyethylene or polypropylene may be used. The protective film may be a film similar to the support film or a different film.

[Printed wiring board]
The printed wiring board of the present embodiment comprises a permanent mask resist formed of the photosensitive resin composition of the present embodiment. Since the printed wiring board of the present embodiment includes the permanent mask resist formed from the photosensitive resin composition of the present embodiment, the resist has excellent adhesion to underfill and reduces the occurrence of cracks. A pattern is formed.

The method for manufacturing a printed wiring board of the present embodiment is a step of forming a photosensitive layer on a substrate by using the photosensitive resin composition of the present embodiment or the photosensitive element of the present embodiment, and the photosensitive layer. It includes a step of forming a resist pattern by exposure and development, and a step of curing the resist pattern to form a permanent mask resist. The printed wiring board can be manufactured, for example, as follows.

First, a metal-clad laminated substrate such as a copper-clad laminate is prepared, and a photosensitive layer is formed on the substrate. When a photosensitive resin composition is used, a coating film formed by applying the photosensitive resin composition onto a substrate by a method such as a screen printing method, a spray method, a roll coating method, a curtain coating method, or an electrostatic coating method. May be dried at 60 to 110 ° C. to provide a photosensitive layer. The thickness of the coating film may be 10 to 200 μm, 15 to 150 μm, 20 to 100 μm, or 23 to 50 μm. When a photosensitive element is used, the photosensitive layer may be provided by thermally laminating the photosensitive layer of the photosensitive element on a substrate using a laminator.

Next, the negative film is brought into direct contact with the photosensitive layer (or non-contact via a transparent film such as a support film), irradiated with active light, and then the unexposed portion is dissolved and removed (developed) with a dilute alkaline aqueous solution. To form a resist pattern. Examples of the active light include electron beams, ultraviolet rays, X-rays and the like, and ultraviolet rays are preferable. As the light source, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a halogen lamp, or the like can be used. The exposure amount may be 10 to 2000 mJ / cm ² , 100 to 1500 mJ / cm ² or 300 to 1000 mJ / cm ² .

Next, the exposed portion of the photosensitive layer is sufficiently cured by at least one treatment of post-exposure (ultraviolet exposure) and post-heating to form a permanent mask resist. The exposure amount of the post-exposure may be 100 to 5000 mJ / cm ² , 500 to 2000 mJ / cm ² , or 700 to 1500 J / cm ² . The heating temperature of the post-heating may be 100 to 200 ° C., 120 to 180 ° C. or 135 to 165 ° C. The heating time for post-heating may be 5 minutes to 12 hours, 10 minutes to 6 hours, or 30 minutes to 2 hours. After that, wiring is formed by etching, and a printed wiring board is produced. The thickness of the permanent mask resist may be 10-50 μm, 15-40 μm or 20-30 μm.

Hereinafter, the purpose and advantages of the present embodiment will be described more specifically based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(Synthesis Example 1)
In a flask equipped with a stirrer, a reflux cooler and a thermometer, bisphenol F novolak type epoxy resin (EXA-7376, manufactured by DIC Co., Ltd., in general formula (II), Y ³ and Y ⁴ are glycidyl groups, R ¹² Bisphenol F novolak type epoxy resin having a structure in which is a hydrogen atom, epoxy equivalent: 186) 350 parts by mass, 70 parts by mass of acrylic acid, 0.5 parts by mass of methylhydroquinone and 120 parts by mass of carbitol acetate are charged at 90 ° C. The mixture was completely dissolved by heating and stirring. Next, the obtained solution was cooled to 60 ° C., 2 parts by mass of triphenylphosphine was added, and the mixture was heated to 100 ° C. and reacted until the acid value of the solution became 1 mgKOH / g or less. To the solution after the reaction, 98 parts by mass of tetrahydrophthalic anhydride (THPAC) and 85 parts by mass of carbitol acetate were added, and the mixture was reacted at 80 ° C. for 6 hours. Then, it cooled to room temperature to obtain THPAC-modified bisphenol F novolak type epoxy acrylate (epoxy acrylate (1)) as a component (A1) having a solid content of 73% by mass.

(Synthesis Example 2)
In a flask equipped with a stirrer, a reflux cooler and a thermometer, a bisphenol F type epoxy resin (in the general formula (IV), a bisphenol F type epoxy resin having a structure ⁱⁿ which Y6 is a hydrogen atom and ^R14 is a hydrogen atom, Epoxy equivalent: 526) 1052 parts by mass of acrylic acid, 1 part by mass of methylhydroquinone, 850 parts by mass of carbitol acetate and 100 parts by mass of solvent naphtha were charged, and the mixture was dissolved by heating and stirring at 70 ° C. Next, the solution was cooled to 50 ° C., 2 parts by mass of triphenylphosphine and 75 parts by mass of solvent naphtha were added, and the mixture was heated to 100 ° C. and reacted until the acid value of the solution became 1 mgKOH / g or less. Next, 745 parts by mass of THPAC, 75 parts by mass of carbitol acetate and 75 parts by mass of solvent naphtha were added to the solution after the reaction, and the mixture was reacted at 80 ° C. for 6 hours. Then, the mixture was cooled to room temperature to obtain a THPAC-modified bisphenol F type epoxy acrylate (epoxy acrylate (2)) as a component (A2) having a solid acid value of 80 mgKOH / g and a solid content of 62% by mass.

(Examples 1 to 6, Comparative Examples 1 to 2)
Each component was blended according to the blending composition shown in Table 1 and kneaded with a three-roll mill to prepare a photosensitive resin composition. Carbitol acetate was added so that the solid content concentration became 70% by mass to obtain a photosensitive resin composition. Table 1 shows the mass parts of the solid content of the components (A), (C) to (F) when the total solid content of the photosensitive resin composition is used as a reference. The numerical value of the component (B) in Table 1 is the equivalent ratio of the epoxy group contained in the component (B) to the carboxyl group contained in the component (A).

Details of each material in Table 1 are as follows.
-Epoxy acrylate (1): Acid-modified vinyl group-containing epoxy resin obtained in Synthesis Example 1-Epoxy acrylate (2): Acid-modified vinyl group-containing epoxy resin obtained in Synthesis Example 2-YX4000X: Biphenyl-type epoxy resin ( Mitsubishi Chemical Co., Ltd., product name)
-Irgacure 907: 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanone (manufactured by BASF, trade name)
-Irgacure 819: Bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (manufactured by BASF, trade name)
-DETX-S: 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., trade name)
・ DPHA: Dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd., trade name)
・ Phthalocyanine pigment: C.I. I. Pigment Blue 15 (manufactured by Sanyo Pigment Co., Ltd., product name)
-B34: Barium sulfate particles (manufactured by Sakai Chemical Industry Co., Ltd., trade name, average particle size: 0.3 μm)
-SFP20M: Silica particles (manufactured by Denka Co., Ltd., trade name, average particle size: 0.3 μm)
-Melamine compound: Finely pulverized melamine (manufactured by Nissan Chemical Industries, Ltd., trade name)

Each evaluation was performed using the photosensitive resin composition under the conditions shown below. The results are shown in Table 2.

[Preparation of test piece]
The photosensitive resin compositions of Examples and Comparative Examples were applied to a copper-clad laminated substrate (MCL-E-67, manufactured by Hitachi Kasei Co., Ltd.) having a thickness of 0.6 mm so that the thickness after drying was 35 μm. After applying by the screen printing method, it was dried at 80 ° C. for 20 minutes using a hot air circulation type dryer. Next, a negative mask having a predetermined pattern was brought into close contact with the coating film and exposed with an exposure amount of 600 mJ / cm ² using an ultraviolet exposure apparatus. Then, it was spray-developed with a 1 mass% sodium carbonate aqueous solution at a pressure of ^1.765 × 105 Pa for 60 seconds to dissolve and develop the unexposed portion. Next, the test piece was exposed to an exposure amount of 1000 mJ / cm ² using an ultraviolet exposure device and heated at 150 ° C. for 1 hour to prepare a test piece having a permanent mask resist.

[Resolution]
The open via portion of the test piece was observed with a 1000 times metallurgical microscope. The resolution was judged based on the following criteria.
A: The via was open and no resist residue was generated at the bottom of the via.
B: The via is open, but a resist residue is generated at the bottom of the via.
C: The via did not open.

[Underfill adhesion]
After adhering a circular mold underfill (CEL-C-3730 (manufactured by Hitachi Kasei Co., Ltd.)) with a diameter of 3.0 mm on the permanent mask resist of the test piece, the mold underfill is parallel to the test piece. The fill was scratched and the state of one side of the test after peeling off the mold underfill was observed. Judgment was made based on the following criteria.
A: Since the underfill and the resist adhered to each other with high strength, the resist disappeared from the peeled portion, and the copper foil surface of the test piece material was deposited.
B: Although the adhesion between the underfill and the resist was excellent, a part of the resist remained in the peeled portion.
C: Due to poor adhesion between the underfill and the resist, the resist completely remained on the peeled portion.

[Solder heat resistance]
A water-soluble flux was applied to the test piece and immersed in a solder bath at 265 ° C. for 10 seconds. This was set as one cycle, and after repeating 6 cycles, the appearance of the permanent mask resist was visually observed and evaluated according to the following criteria.
A: There was no change in appearance within the permanent mask resist 30 cm × 30 cm.
B: 1 to 5 floats or blister of the coating film were generated in the permanent mask resist 30 cm × 30 cm.
C: Six or more floats or blister of the coating film were generated in the permanent mask resist 30 cm × 30 cm.

[Solvent resistance]
The test piece was immersed in isopropyl alcohol at room temperature (25 ° C., the same applies hereinafter) for 30 minutes, and after confirming that there was no abnormality in the appearance of the permanent mask resist, a peeling test was performed with cellophane tape.
A: There was no abnormality in the appearance of the permanent mask resist, and no peeling occurred.
B: There was a slight change in the appearance of the permanent mask resist.
C: The appearance of the permanent mask resist is abnormal or peeled off.

[Acid resistance]
The test piece was immersed in a 10 mass% hydrochloric acid aqueous solution at room temperature for 30 minutes, and after confirming that there was no abnormality in the appearance of the permanent mask resist, a peeling test was performed with cellophane tape.
A: There was no abnormality in the appearance of the permanent mask resist, and no peeling occurred.
B: There was a slight change in the appearance of the permanent mask resist.
C: The appearance of the permanent mask resist is abnormal or peeled off.

[Alkali resistance]
The test piece was immersed in a 5 mass% sodium hydroxide aqueous solution at room temperature for 30 minutes, and after confirming that there was no abnormality in the appearance of the permanent mask resist, a peeling test was performed with cellophane tape.
A: There was no abnormality in the appearance of the permanent mask resist, and no peeling occurred.
B: There was a slight change in the appearance of the permanent mask resist.
C: The appearance of the permanent mask resist is abnormal or peeled off.

[Insulation (electrical insulation)]
A test piece was used in the same manner as in the above [Preparation of test piece] except that a bismaleimide triazine substrate on which a comb-shaped electrode (line / space = 10 μm / 10 μm) was formed was used instead of the copper-clad laminated substrate. It was formed and exposed to 135 ° C., 85%, 5V conditions. Then, the degree of migration was observed with a 100x metallurgical microscope and evaluated according to the following criteria.
A: Even after 200 hours, the resistance value did not drop to ^10-6 Ω or less without migration occurring in the permanent mask resist.
B: For 100 hours or more and less than 200 hours, the resistance value did not drop to ^10-6 Ω or less without migration occurring in the permanent mask resist.
C: Within less than 100 hours, migration occurred in the permanent mask resist, and the resistance value dropped to ^10-6 Ω or less.

From Table 2, it can be confirmed that the photosensitive resin compositions of Examples 1 to 6 are excellent in underfill adhesion and crack resistance.

(Examples 7 to 12, Comparative Examples 3 to 4)
Each of the photosensitive resin compositions of Examples 1 to 6 and Comparative Examples 1 and 2 prepared in the blending ratios shown in Table 1 was diluted with methyl ethyl ketone, applied on a PET film, dried at 90 ° C. for 10 minutes, and thickened. A photosensitive layer made of a photosensitive resin composition having a thickness of 25 μm was formed. Further, a protective film was laminated on the protective film to prepare photosensitive elements of Examples 7 to 12, Comparative Examples 3 and 4.

[Evaluation of photosensitive element]
The protective film is peeled off from the photosensitive element, the photosensitive layer of the photosensitive element is heat-laminated on a solid copper foil substrate, and then exposed in the same manner as described in the above [Preparation of test piece] to perform a permanent mask resist. A test piece having the above was prepared.

Using the obtained test piece, the same evaluation as in Example 1 was performed. The results are shown in Table 3.

From Table 3, it can be confirmed that the photosensitive elements of Examples 7 to 12 are excellent in underfill adhesion and crack resistance.

1 ... Photosensitive element, 10 ... Support film, 20 ... Photosensitive layer, 30 ... Protective film.

Claims (9)

It contains (A) an acid-modified vinyl group-containing epoxy resin, (B) an epoxy compound, (C) a photopolymerization initiator, and (D) a photopolymerizable compound.
The equivalent ratio of the epoxy group contained in the (B) epoxy compound to the carboxyl group contained in the (A) acid-modified vinyl group-containing epoxy resin is 1.2 to 4.0.
The acid-modified vinyl group-containing epoxy resin (A) is saturated with an esterified product of a bisphenol novolak type epoxy resin having a structural unit represented by the following general formula (I) or (II) and a vinyl group-containing monocarboxylic acid. Alternatively, an acid-modified vinyl group-containing epoxy resin (A1), which is an addition reaction product to which unsaturated polybasic acid anhydride is added, a novolak type epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a triphenol methane type epoxy. An acid-modified vinyl group-containing epoxy resin which is an addition reaction product obtained by adding a saturated or unsaturated polybasic acid anhydride to an esterified product of at least one epoxy resin selected from the group consisting of resins and a vinyl group-containing monocarboxylic acid. A photosensitive resin composition comprising (A2) and.

[In formula (I), R ¹¹ represents a hydrogen atom or a methyl group, and a plurality of R ¹¹ may be the same or different. Y ¹ and Y ² each independently represent a hydrogen atom or a glycidyl group, but at least one of Y ¹ and Y ² is a glycidyl group. ]

[In formula (II), R ¹² represents a hydrogen atom or a methyl group, and a plurality of R ^12s may be the same or different, and Y ³ and Y ⁴ each independently represent a hydrogen atom or a glycidyl group, but Y. At least one of ³ and ^Y4 is a glycidyl group. ] The acid-modified vinyl group-containing epoxy resin (A2) is a novolak type epoxy resin having a structural unit represented by the following general formula (III), and a bisphenol A type epoxy having a structural unit represented by the following general formula (IV). An ester of at least one epoxy resin selected from the group consisting of a resin or a bisphenol F type epoxy resin and a triphenol methane type epoxy resin having a structural unit represented by the following general formula (V) and a vinyl group-containing monocarboxylic acid. The photosensitive resin composition according to claim 1, which is an addition reaction product obtained by adding a saturated or unsaturated polybasic acid anhydride to a product.

[In formula (III), R ¹³ represents a hydrogen atom or a methyl group, and Y ⁵ represents a hydrogen atom or a glycidyl group].

[In formula (IV), R ¹⁴ represents a hydrogen atom or a methyl group, and a plurality of R ¹⁴ may be the same or different, and Y ⁶ represents a hydrogen atom or a glycidyl group. ]

[In formula (V), Y ⁷ represents a hydrogen atom or a glycidyl group, and a plurality of Y ^7s may be the same or different, and at least one Y ⁷ is a glycidyl group. ] The photosensitive resin composition according to claim 1 or 2, wherein the (C) photopolymerization initiator contains an acylphosphine oxide-based photopolymerization initiator. (E) The photosensitive resin composition according to any one of claims 1 to 3, further containing a pigment. (F) The photosensitive resin composition according to any one of claims 1 to 4, further containing an inorganic filler. A photosensitive element comprising a support film and a photosensitive layer made of the photosensitive resin composition according to any one of claims 1 to 5. A printed wiring board comprising a permanent mask resist formed by the photosensitive resin composition according to any one of claims 1 to 5. The printed wiring board according to claim 7, wherein the permanent mask resist has a thickness of 10 to 50 μm. A step of forming a photosensitive layer on a substrate by using the photosensitive resin composition according to any one of claims 1 to 5 or the photosensitive element according to claim 6.
The step of exposing and developing the photosensitive layer to form a resist pattern,
The step of curing the resist pattern to form a permanent mask resist,
Manufacturing method of printed wiring board including.

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