JP7459887B2 - Photosensitive resin composition, photosensitive element, printed wiring board, and method for producing printed wiring board - Google Patents

Description

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

In the field of printed wiring boards, permanent mask resist is formed on printed wiring boards. The permanent mask resist prevents corrosion of the conductor layer and maintains electrical insulation between the conductor layers when the printed wiring board is in use. In recent years, permanent mask resist also serves as a solder resist film that prevents solder from adhering to unnecessary parts of the conductor layer of the printed wiring board in processes such as flip-chip mounting and wire bonding mounting of semiconductor elements on the printed wiring board via solder.

Conventionally, permanent mask resists have been produced by a screen printing method using a thermosetting resin composition or a photographic method using a photosensitive resin composition. For example, in flexible wiring boards that use mounting methods such as FC (Flip Chip), TAB (Tape Automated Bonding), and COF (Chip On Film), the wiring pattern portion that connects to IC chips, electronic components, or LCD (Liquid Crystal Display) panels With the exception of , a thermosetting resin paste is screen printed and thermally cured to form a permanent mask resist (for example, see Patent Document 1).

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

JP 2003-198105 A Japanese Patent Application Publication No. 11-240930

On the other hand, permanent mask resists formed from conventional photosensitive resin compositions do not have sufficient adhesion with underfill in harsh environments such as high temperatures, and cracks may occur in the permanent mask resists. There is.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a photosensitive resin composition capable of forming a permanent mask resist that has excellent adhesion to underfill and reduces the occurrence of cracks, and a photosensitive resin composition using the photosensitive resin composition. An object of the present invention is to provide an element, a printed wiring board, and a method for manufacturing the printed wiring board.

A first aspect of the present invention comprises (A) an acid-modified vinyl group-containing epoxy resin, (B) an epoxy compound, (C) a photopolymerization initiator, and (D) a photopolymerizable compound; The present invention relates to a photosensitive resin composition in which the equivalent ratio of the epoxy group contained in the epoxy compound (B) 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 comprising a support film and a photosensitive layer made of the photosensitive resin composition described above.
A third aspect of the present invention relates to a printed wiring board provided with a permanent mask resist formed from 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. and curing the resist pattern to form a permanent mask resist.

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

FIG. 1 is a cross-sectional view schematically showing a photosensitive element of this embodiment.

Hereinafter, one embodiment of the present invention will be specifically described, but the present invention is not limited thereto. It goes without saying that in the following embodiments, the constituent elements (including elemental steps, etc.) are not necessarily essential, except when specifically specified or when they are clearly considered essential in principle. This also applies to numerical values and ranges, and should not be construed as unduly limiting the present invention.

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

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

The photosensitive resin composition has excellent adhesion to underfill and can form a permanent mask resist with reduced cracking. The photosensitive resin composition also has excellent flowability and can form a permanent mask resist with excellent adhesion to copper substrates. Furthermore, the photosensitive resin composition is excellent in performance such as resolution, electrical insulation, solder heat resistance, thermal shock resistance, solvent resistance, acid resistance, and alkali resistance required for photosensitive resin compositions used in the manufacture of printed wiring boards.

<(A) Acid-modified vinyl group-containing epoxy resin>
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 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 and a vinyl group-containing monocarboxylic acid can be used.

As the component (A), for example, as an epoxy resin, an acid-modified vinyl group-containing epoxy resin (A1 ) (hereinafter sometimes referred to as component (A1)), acid-modified product obtained using an epoxy resin (a2) other than epoxy resin (a1) (hereinafter sometimes referred to as epoxy resin (a2)) Examples include vinyl group-containing epoxy resin (A2) (hereinafter sometimes referred to as component (A2)). These can be used alone or in combination of two or more.

(Epoxy resin (a1))
Examples of the epoxy resin (a1) include epoxy resins having a structural unit represented by the following general formula (I) or (II); preferable.

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

From the viewpoint of improving 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 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. If the number of structural units is within the above range, it becomes easier to improve adhesion to the underfill, heat resistance, and electrical insulation. Here, the number of structural units of a structural unit indicates an integer value in a single molecule, and indicates a rational number that is an average value in an aggregate of multiple types of molecules. The same applies to the number of structural units of a structural unit below.

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

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, adhesion with the underfill, heat resistance, and electrical insulation properties can be easily improved.

In the general formula (II), an epoxy resin in which R ¹² is a hydrogen atom and Y ³ and Y ⁴ are glycidyl groups is commercially available as the EXA-7376 series (trade name, manufactured by DIC Corporation), and an epoxy resin in which R ¹² is a methyl group and Y ³ and Y ⁴ are glycidyl groups is commercially available as the EPON SU8 series (trade name, manufactured by Japan Epoxy Resins Co., Ltd.).

(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). From the viewpoint of improving adhesion to the underfill, however, it is preferably at least one selected from the group consisting of novolac type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, and triphenolmethane type epoxy resins.

Examples of novolak-type epoxy resins include epoxy resins having a structural unit represented by the following general formula (III). Examples of bisphenol A-type epoxy resins and bisphenol F-type epoxy resins include epoxy resins having a structural unit represented by the following general formula (IV). Examples of the triphenolmethane 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 epoxy resin having a structural unit represented by general formula (III) and an epoxy resin having a structural unit represented by general formula (IV). More preferred. The epoxy resin having a structural unit represented by general formula (IV) is preferably a bisphenol F type epoxy resin.

As the epoxy resin (a2), a novolac-type epoxy resin having a structural unit represented by the following general formula (III) is preferable. An example of a novolac-type epoxy resin having such a structural unit is a novolac-type epoxy resin represented by the following general formula (III').

In formulas (III) and (III'), ^R13 represents a hydrogen atom or a methyl group, and ^Y5 represents a hydrogen atom or a glycidyl group, provided that at least one of ^Y5 is a glycidyl group. In formula (III'), _n1 is a number of 1 or more, and multiple ^R13s and ^Y5s may be the same or different.

From the viewpoint of improving 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/ It may be 90. As can be seen from this molar ratio, at least one of Y ⁵ is a glycidyl group.

_n1 is 1 or more, but may be 10 to 200, 30 to 150, or 30 to 100. When _n1 is within the above range, adhesion to the underfill, heat resistance, and electrical insulation are easily improved.

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

Examples of phenol novolac type epoxy resins or cresol novolac type epoxy resins represented by general formula (III') include YDCN-701, YDCN-702, YDCN-703, YDCN-704, YDCN-704L, YDPN-638, YDPN-602 (all of which are product names manufactured by Nippon Steel Chemical Co., Ltd.), DEN-431, DEN-439 (all of which are product names manufactured by Dow Chemical Co., Ltd.), EOCN-120, and EOCN-10. Commercially available products include EOCN-2S, EOCN-103S, EOCN-104S, EOCN-1012, EOCN-1025, EOCN-1027, BREN (all trade names manufactured by Nippon Kayaku Co., Ltd.), EPN-1138, EPN-1235, EPN-1299 (all trade names manufactured by BASF), N-730, N-770, N-865, N-665, N-673, VH-4150, VH-4240 (all trade names manufactured by DIC Corporation), etc.

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

In formulas (IV) and (IV'), ^R14 represents a hydrogen atom or a methyl group, and a plurality of ^R14s may be the same or different, and ^Y6 represents a hydrogen atom or a glycidyl group. In formula (IV'), _n2 represents a number of 1 or more, and when _n2 is 2 or more, a plurality of ^Y6s may be the same or different, and at least one ^Y6 is a glycidyl group.

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

_n2 represents 1 or more, but may be 10 to 100, 10 to 80, or 15 to 60. When _n2 is within the above range, adhesion to the underfill, heat resistance, and electrical insulation are easily improved.

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

To promote the reaction between hydroxyl groups and epichlorohydrin, it is preferable to carry out the reaction in a polar organic solvent such as dimethylformamide, dimethylacetamide, or dimethylsulfoxide in the presence of an alkali metal hydroxide at a reaction temperature of 50 to 120°C. If the reaction temperature is within the above range, the reaction does not slow down too much and side reactions can be suppressed.

Bisphenol A type epoxy resins or bisphenol F type epoxy resins represented by general formula (IV') are commercially available, such as Epicoat 807, 815, 825, 827, 828, 834, 1001, 1004, 1007 and 1009 (all of which are product names manufactured by Japan Epoxy Resins Co., Ltd.), DER-330, DER-301, DER-361 (all of which are product names manufactured by The Dow Chemical Company, Ltd.), YD-8125, YDF-170, YDF-170, YDF-175S, YDF-2001, YDF-2004 and YDF-8170 (all of which are product names manufactured by Nippon Steel Chemical Co., Ltd.).

Preferred examples of the epoxy resin (a2) include triphenolmethane type epoxy resins having a structural unit represented by the following general formula (V). Examples of the triphenolmethane epoxy resin having such a structural unit include the triphenolmethane epoxy resin represented by the general formula (V').

In formulas (V) and (V'), Y ⁷ represents a hydrogen atom or a glycidyl group, a plurality of Y ^7s may be the same or different, and at least one Y ⁷ is a glycidyl group. In formula (V'), _n3 represents a number of 1 or more.

From the viewpoint of improving 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 Y ⁷ is a glycidyl group.

n ₃ is 1 or more, but may be 10-100, 15-80, or 15-70. When _n3 is within the above range, adhesion with the underfill, heat resistance, and electrical insulation are likely to improve.

Triphenolmethane type epoxy resins represented by general formula (V') are commercially available, such as FAE-2500, EPPN-501H, and EPPN-502H (all trade names manufactured by Nippon Kayaku Co., Ltd.).

Component (A1) and component (A2) are epoxy resin (a1) and epoxy resin (a2) (hereinafter sometimes collectively referred to as "component (a)") from the viewpoint of improving resolution. , vinyl group-containing monocarboxylic acid (b) (hereinafter sometimes referred to as component (b)) and esterified products (A1') and (A2') (hereinafter collectively referred to as "(A It is preferable that it is an addition reaction product in which a saturated or unsaturated polybasic acid anhydride (c) (hereinafter sometimes referred to as component (c)) is added to component '). .

(Vinyl group-containing monocarboxylic acid (b))
Component (b) includes, for example, acrylic acid, acrylic acid dimer, methacrylic acid, β-furfurylacrylic acid, β-styrylacrylic acid, cinnamic acid, crotonic acid, α-cyanocinnamic acid, etc. Derivatives, half-ester compounds that are the reaction products of hydroxyl group-containing acrylates and dibasic acid anhydrides, vinyl group-containing monoglycidyl ethers, or half-esters that are the reaction products of vinyl group-containing monoglycidyl esters and dibasic acid anhydrides. Examples include compounds.

The half-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. 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, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipentaerythritol pentaacrylate, pentaerythritol pentamethacrylate, glycidyl acrylate and glycidyl methacrylate.

Examples of dibasic acid anhydrides include succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, ethyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride. , ethylhexahydrophthalic anhydride and itaconic anhydride.

In the reaction between the above components (a) and (b), it is preferable to react in a ratio where 0.6 to 1.05 equivalents of component (b) are used per equivalent of epoxy groups in component (a), and it is even more preferable to react in a ratio where 0.8 to 1.0 equivalents are used. By reacting in such a ratio, photopolymerization is improved, that is, photosensitivity is increased, and therefore resolution is improved.

Component (a) and component (b) can be dissolved in an organic solvent and reacted. Examples of organic solvents 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, and 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 include petroleum solvents such as ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha.

A catalyst may be used to promote the reaction between component (a) and component (b), such as 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 may be 0.01 to 10 parts by mass, 0.05 to 2 parts by mass, or 0.1 to 1 part by mass, relative to 100 parts by mass of the total of the component (a) and the component (b).

To prevent polymerization during the reaction, it is preferable to use a polymerization inhibitor. Examples of polymerization inhibitors include hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, catechol, pyrogallol, etc. From the viewpoint of improving the storage stability of the composition, the amount of the polymerization inhibitor used may be 0.01 to 1 part by mass, 0.02 to 0.8 parts by mass, or 0.04 to 0.5 parts by mass per 100 parts by mass of the total of components (a) and (b).

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

Component (A') obtained by reacting component (a) with component (b) has a hydroxyl group formed by a ring-opening addition reaction between the epoxy group of component (a) and the carboxyl group of component (b). It is presumed that he does. In addition, by reacting component (A') with component (c), the hydroxyl group of component (A') (including the hydroxyl group originally present in component (a)) and the acid anhydride of component (c) can be combined. It is presumed that this is an acid-modified vinyl group-containing epoxy resin in which the chemical groups are half-esterified.

(Polybasic Acid Anhydride (c))
Examples of component (c) include succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, methyltetrahydrophthalic anhydride, ethyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, ethylhexahydrophthalic anhydride, and itaconic anhydride. Among these, tetrahydrophthalic anhydride is preferred from the viewpoint of obtaining a photosensitive resin composition capable of forming a pattern with excellent resolution.

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

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

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

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

The weight average molecular weight (Mw) of component (A) may be 3,000 to 30,000, 4,000 to 25,000, or 5,000 to 18,000. Within the above range, a resist with excellent resolution can be formed, and the adhesion with the underfill, heat resistance, and electrical insulation can be further improved. Here, Mw is a value measured by gel permeation chromatography (GPC) and converted to standard polystyrene. Mw can be measured, for example, under the following GPC conditions and converted using a standard polystyrene calibration curve. To create a calibration curve, a set of 5 samples ("PStQuick MP-H" and "PStQuick B", manufactured by Tosoh Corporation) can be used as standard polystyrene.
(GPC conditions)
GPC device: High-speed GPC device “HCL-8320GPC”,
Detector: Differential refractometer or UV, Tosoh Co., Ltd. Column: TSKgel SuperMultipore HZ-H (column length: 15 cm, column inner diameter: 4.6 mm), Tosoh Co., Ltd. Eluent: Tetrahydrofuran (THF)
Measurement temperature: 40℃
Flow rate: 0.35mL/min Sample concentration: 10mg/THF5mL
Injection volume: 20μL

The content of component (A) is 20 to 80% by mass, 30 to 70% by mass based on the total solid content of the photosensitive resin composition, from the viewpoint of improving the heat resistance, electrical properties, and chemical resistance of the permanent mask resist. It may be % by weight or 30-50% by weight. In this specification, "solid content" refers to non-volatile content excluding volatile substances such as water and diluent contained in the photosensitive resin composition, and is evaporated when the resin composition is dried. It also refers to components that remain without volatilization, and includes components that are liquid, starch syrup-like, or wax-like at room temperature around 25°C.

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

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

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

Epoxy compounds include, for example, bisphenol A type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins, brominated bisphenol A type epoxy resins, novolac type epoxy resins, bisphenol S type epoxy resins, biphenyl type epoxy resins, heterocyclic epoxy resins such as triglycidyl isocyanurate, and bixylenol type epoxy resins.

From the viewpoint of improving adhesion to the underfill, the equivalent ratio of the epoxy groups contained in component (B) to the carboxyl groups contained in component (A) is 1.2 to 4.0, preferably 1.3 to 3.8, and more preferably 1.5 to 3.5. In other words, the content of component (B) in the photosensitive resin composition is 1.2 to 4.0 equivalents of the epoxy groups contained in component (B) per equivalent of the carboxyl groups contained in component (A), preferably 1.3 to 3.8 equivalents, and more preferably 1.5 to 3.5 equivalents.

<(C) Photopolymerization initiator>
The photopolymerization initiator that is component (C) is not particularly limited as long as it can polymerize the photopolymerizable compound that is component (D). Component (C) includes, for example, an alkylphenone photopolymerization initiator, an acylphosphine oxide photopolymerization initiator, a compound having a thioxanthone skeleton, and a titanocene photopolymerization initiator. Among these, from the viewpoint of improving soldering heat resistance, an alkylphenone photopolymerization initiator or an acylphosphine oxide photopolymerization initiator is preferred. Component (C) can be used alone or in combination of two or more.

Examples of the alkylphenone 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-propanone, 4,4'-bis(dimethylamino)benzophenone (Michler's ketone), 4,4'-bis(diethylamino)benzophenone and 4-methoxy-4'-dimethylaminobenzophenone.

Examples of the acylphosphine oxide 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)-phenylphosphine oxide, (2,5-dihydroxyphenyl)diphenylphosphine oxide, (p-hydroxyphenyl)diphenylphosphine oxide, 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 component (C) may be 0.2 to 15 mass%, 0.4 to 5 mass%, or 0.6 to 1 mass% based on the total solid content of the photosensitive resin composition. If the content of component (C) is 0.2 mass% or more, the exposed area is less likely to dissolve during development, and if it is 15 mass% or less, it is easier to suppress a decrease in heat resistance.

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

Component (D) includes, for example, hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; glycol monomers such as ethylene glycol, methoxytetraethylene glycol, and polyethylene glycol. or di(meth)acrylate; (meth)acrylamide compounds such as N,N-dimethyl(meth)acrylamide and N-methylol(meth)acrylamide; aminoalkyl(meth) such as N,N-dimethylaminoethyl(meth)acrylate; Acrylates; polyhydric alcohols such as hexanediol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, tris-hydroxyethyl isocyanurate, or polyhydric (meth)acrylates of their ethylene oxide or propylene oxide adducts; phenoxy (Meth)acrylate compounds of ethylene oxide or propylene oxide adducts of phenolic compounds such as ethyl (meth)acrylate and polyethoxydi(meth)acrylate of bisphenol A; glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, triglycidyl isocyanurate, etc. (meth)acrylate of glycidyl ether and melamine (meth)acrylate. These (D) components can be used alone or in combination of two or more.

The content of component (D) may be 0.1 to 5 mass%, 0.1 to 3 mass%, or 0.5 to 2 mass% based on the total solid content in the photosensitive resin composition. If it is 2 mass% or more, it is possible to prevent the exposed area from dissolving during development, and if it is 50 mass% or less, it is possible to prevent a decrease in heat resistance.

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

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

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

Component (F) may contain silica from the viewpoint of improving heat resistance, and may contain barium sulfate or a combination of silica and barium sulfate from the viewpoint of improving solder heat resistance, crack resistance (thermal shock resistance), and adhesive strength between the underfill material and the permanent mask resist after PCT resistance test. Component (F) may also contain an inorganic filler that has been surface-treated with alumina or an organosilane compound from the viewpoint of improving the aggregation prevention effect.

The average particle size of 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, a decrease in insulation reliability of the permanent mask resist can be further suppressed.

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

When silica is used as component (F), the content of silica may be 5 to 60 mass%, 15 to 55 mass%, or 15 to 50 mass%, based on the total solid content of the photosensitive resin composition. When barium sulfate is used as component (F), the content of barium sulfate may be 5 to 30 mass%, 5 to 25 mass%, or 5 to 20 mass%, based on the total solid content of the photosensitive resin composition. When the content is 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) Curing Agent>
The photosensitive resin composition of the present embodiment may further contain a curing agent as component (G). The component (G) may be a compound that is cured by itself with heat, ultraviolet light, or the like, or a compound that is cured by heat, ultraviolet light, or the like together with a carboxyl group or hydroxyl group of component (A), which is a photocurable component in the photosensitive resin composition of the present embodiment. By using a curing agent, the heat resistance, adhesion, chemical resistance, and the like of the permanent mask resist can be improved.

Component (G) may be, for example, a thermosetting compound such as a melamine compound or an oxazoline compound. Melamine compounds may be, for example, triaminotriazine, hexamethoxymelamine, and hexabutoxylated melamine. Component (G) may be used alone or in combination of two or more.

When component (G) is used, its content 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 permanent mask resist to be formed can be further improved while maintaining good developability.

The photosensitive resin composition of this embodiment contains a curing accelerator for accelerating the curing of component (D) in order to further improve the properties such as heat resistance, adhesion, and chemical resistance of the permanent mask resist. May be used together.

Examples of the curing accelerator include imidazole derivatives such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-phenylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole; guanamines such as acetoguanamine and benzoguanamine; polyamines such as diaminodiphenylmethane, m-phenylenediamine, m-xylylenediamine, diaminodiphenylsulfone, dicyandiamide, urea, urea derivatives, melamine, and polybasic hydrazides; organic acid salts or epoxy adducts thereof; amine complexes of boron trifluoride; and triazine derivatives such as ethyldiamino-S-triazine, 2,4-diamino-S-triazine, and 2,4-diamino-6-xylyl-S-triazine. The curing accelerators can be used alone or in combination of two or more.

From the viewpoint of improving reliability, 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. It may be.

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

Examples of the component (H) include thermoplastic elastomers such as styrene elastomers, olefin elastomers, urethane elastomers, polyester elastomers, polyamide elastomers, acrylic elastomers, and silicone elastomers. Thermoplastic elastomers are composed of hard segment components that contribute to heat resistance and strength, and soft segment components that contribute to flexibility and toughness. Component (H) can be used alone or in combination of two or more.

As the urethane elastomer, it is possible to use a compound composed of a hard segment made of a low molecular weight (short chain) diol and a diisocyanate, and a soft segment made of a high molecular weight (long chain) diol and diisocyanate. Examples of low-molecular diols include ethylene glycol, propylene glycol, 1,4-butanediol, and bisphenol A. Examples of polymeric diols 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 low molecular weight diol is preferably 48 to 500. The Mn of the polymeric diol is preferably 500 to 10,000. As urethane elastomers, 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 elastomer, a compound obtained by polycondensing a dicarboxylic acid or its derivative and a diol compound or its derivative can be used. Examples of dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalene dicarboxylic acid, and aromatic dicarboxylic acids in which the hydrogen atom of the aromatic nucleus of these acids is substituted with a methyl group, ethyl group, phenyl group, etc.; adipic acid; , aliphatic dicarboxylic acids having 2 to 20 carbon atoms such as sebacic acid and dodecanedicarboxylic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid.

Examples of diol compounds 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 include cyclic diols and dihydric phenols represented by the following general formula (VI).

In 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, ^R1 and ^R2 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 12 carbon atoms, l and m each independently represent an integer of 0 to 4, and p is 0 or 1. The alkylene group and 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 resorcinol. These compounds can be used alone or in combination of two or more.

As polyester-based elastomers, multiblock copolymers can be used in which aromatic polyester (e.g., polybutylene terephthalate) is used as the hard segment component and aliphatic polyester (e.g., polytetramethylene glycol) is used as the soft segment component. There are various grades of polyester-based elastomers depending on the type, ratio, and molecular weight of the hard and soft segments. Commercially available polyester-based elastomers include Hytrel (manufactured by DuPont-Toray Industries, Inc., "Hytrel" is a registered trademark), Pelprene (manufactured by Toyobo Co., Ltd., "Pelprene" is a registered trademark), and Espel (manufactured by Hitachi Chemical Co., Ltd., "Espel" is a registered trademark).

The acrylic elastomer may be a compound containing an acrylic acid ester-based structural unit as a main component. Examples of acrylic acid esters 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 obtained by further copolymerizing a monomer having a functional group that serves as a crosslinking point. Examples of monomers having a functional group include glycidyl methacrylate and allyl glycidyl ether. Examples of acrylic elastomers include acrylonitrile-butyl acrylate copolymer, acrylonitrile-butyl acrylate-ethyl acrylate copolymer, and acrylonitrile-butyl acrylate-glycidyl methacrylate copolymer.

As an elastomer other than the thermoplastic elastomer, a rubber-modified epoxy resin may be used. The rubber-modified epoxy resin can be obtained, for example, by modifying 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 with a butadiene-acrylonitrile rubber modified at both ends with a carboxylic acid, a silicone rubber modified at both ends with an amino, or the like. Among these elastomers, from the viewpoint of shear adhesion, a butadiene-acrylonitrile copolymer modified at both ends with a carboxyl group, and Espel (Hitachi Chemical Co., Ltd., Espel 1612, 1620), which is a polyester-based elastomer having a hydroxyl group, are preferred.

The content of component (H) may be 2 to 40 parts by weight, 4 to 30 parts by weight, 10 to 25 parts by weight, or 15 to 22 parts by weight, per 100 parts by weight of component (A). By keeping the content within the above range, the unexposed parts of the photosensitive layer are more easily dissolved by the developer, and the elastic modulus of the permanent mask resist in high temperature regions is lowered.

<Other ingredients>
If necessary, a diluent such as an organic solvent may be mixed into the photosensitive resin composition of this embodiment in order to adjust the viscosity. Examples of organic solvents 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 include petroleum solvents such as ether, petroleum naphtha, hydrogenated 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. By keeping the content within the above ranges, the coatability of the photosensitive resin composition is improved, making it possible to form a more precise pattern.

The photosensitive resin composition of this embodiment may further be mixed with various additives, if necessary. Examples of additives include polymerization inhibitors such as hydroquinone, methylhydroquinone, hydroquinone monomethyl ether, catechol, and pyrogallol; thickeners such as bentone and montmorillonite; silicone-based, fluorine-based, or vinyl resin-based antifoaming agents; silane cups. Ringing agents; flame retardants such as brominated epoxy compounds, acid-modified brominated epoxy compounds, antimony compounds, phosphate compounds of phosphorus compounds, aromatic condensed phosphoric esters, and halogen-containing condensed phosphoric esters.

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

[Photosensitive element]
The photosensitive element of this embodiment includes a support film and a photosensitive layer made of the photosensitive resin composition of this embodiment. Fig. 1 is a cross-sectional view showing a schematic diagram of the photosensitive element of this 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. In addition, a protective film 30 that covers the photosensitive layer 20 may be further provided on the photosensitive layer 20.

The photosensitive element 1 of this embodiment is produced by applying the photosensitive resin composition of this embodiment onto a support film 10 by a known method such as reverse roll coating, gravure roll coating, comma coating, curtain coating, etc. , the photosensitive layer 20 can be produced by drying a coating film.

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 10-50 μm, 15-40 μm or 20-30 μm.

To dry the coating film, 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. Further, the drying time may be 1 to 60 minutes, 2 to 30 minutes, or 5 to 20 minutes.

In the photosensitive element 1 of this embodiment, a protective film 30 can also 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 the same film as the support film or may be a different film.

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

The method for producing a printed wiring board of this embodiment includes the steps of forming a photosensitive layer on a substrate using the photosensitive resin composition of this embodiment or the photosensitive element of this embodiment, exposing and developing the photosensitive layer to form a resist pattern, and curing the resist pattern to form a permanent mask resist. The printed wiring board can be produced, for example, as follows.

First, a metal-clad laminate substrate such as a copper-clad laminate is prepared, and a photosensitive layer is formed on the substrate. When using a photosensitive resin composition, 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. A photosensitive layer may be provided by drying at 60 to 110°C. The thickness of the coating film may be 10-200 μm, 15-150 μm, 20-100 μm or 23-50 μm. When using a photosensitive element, the photosensitive layer may be provided by thermally laminating the photosensitive layer of the photosensitive element onto the substrate using a laminator.

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

Next, the exposed portions of the photosensitive layer are sufficiently cured by at least one of post-exposure (ultraviolet light 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 for 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. Thereafter, 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.

The objectives and advantages of this embodiment will be explained in more detail below 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 condenser, and a thermometer, a bisphenol F novolac type epoxy resin (EXA-7376, manufactured by DIC Corporation, general formula (II), Y ³ and Y ⁴ are glycidyl groups, R ¹² A bisphenol F novolak type epoxy resin having a structure in which is a hydrogen atom, 350 parts by mass of epoxy equivalent: 186), 70 parts by mass of acrylic acid, 0.5 parts by mass of methylhydroquinone and 120 parts by mass of carbitol acetate were charged, and the mixture was heated 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. 98 parts by mass of tetrahydrophthalic anhydride (THPAC) and 85 parts by mass of carbitol acetate were added to the solution after the reaction, and the mixture was reacted at 80° C. for 6 hours. Thereafter, the mixture was cooled to room temperature to obtain a THPAC-modified bisphenol F novolac type epoxy acrylate (epoxy acrylate (1)) as component (A1) having a solid content of 73% by mass.

(Synthesis example 2)
In a flask equipped with a stirrer, a reflux condenser, and a thermometer, a bisphenol F-type epoxy resin (bisphenol F-type epoxy resin having a structure in which ^Y6 is a hydrogen atom and ^R14 is a hydrogen atom in the general formula (IV), Epoxy equivalent: 526) 1052 parts by mass, 144 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, 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. Thereafter, the mixture was cooled to room temperature to obtain a THPAC-modified bisphenol F-type epoxy acrylate (epoxy acrylate (2)) as 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)
The components were mixed according to the composition shown in Table 1 and kneaded in a three-roll mill to prepare a photosensitive resin composition. Carbitol acetate was added so that the solids concentration was 70% by mass, to obtain a photosensitive resin composition. Table 1 shows the parts by mass of the solids of components (A) and (C) to (F) based on the total solids content of the photosensitive resin composition. The value for component (B) in Table 1 is the equivalent ratio of the epoxy groups contained in component (B) to the carboxyl groups contained in 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 (manufactured by Mitsubishi Chemical Corporation, trade name)
Irgacure 907: 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone (BASF Corporation, trade name)
Irgacure 819: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BASF Corporation, trade name)
DETX-S: 2,4-diethylthioxanthone (trade name, manufactured by Nippon Kayaku Co., Ltd.)
DPHA: Dipentaerythritol hexaacrylate (trade name, manufactured by Nippon Kayaku Co., Ltd.)
Phthalocyanine pigment: C.I. Pigment Blue 15 (manufactured by Sanyo Dye Co., Ltd., product name)
B34: Barium sulfate particles (manufactured by Sakai Chemical Industry Co., Ltd., product name, average particle size: 0.3 μm)
SFP20M: Silica particles (manufactured by Denka Co., Ltd., product name, average particle size: 0.3 μm)
Melamine compound: finely ground melamine (product name, manufactured by Nissan Chemical Industries, Ltd.)

The photosensitive resin composition was used to carry out the evaluations under the conditions shown below. The results are shown in Table 2.

[Preparation of test specimens]
The photosensitive resin compositions of the examples and comparative examples were applied to a 0.6 mm thick copper-clad laminate substrate (MCL-E-67, manufactured by Hitachi Chemical Co., Ltd.) by screen printing so that the thickness after drying was 35 μm, and then dried at 80 ° C. for 20 minutes using a hot air circulation dryer. Next, a negative mask having a predetermined pattern was attached to the coating film, and exposed to an exposure amount of 600 mJ / cm ² using an ultraviolet exposure device. Thereafter, the coating was spray-developed with a 1 mass % aqueous sodium carbonate solution for 60 seconds at a pressure of 1.765 × 10 ⁵ Pa, and the unexposed parts were dissolved and developed. Next, the coating 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 using a metallurgical microscope with a magnification of 1000 times. Resolution was judged based on the following criteria.
A: The via was open, and no resist residue was formed at the bottom of the via.
B: The via was open, but resist residue was present at the bottom of the via.
C: Via did not open.

[Underfill adhesion]
After adhering a circular mold underfill (CEL-C-3730 (manufactured by Hitachi Chemical Co., Ltd.) with a diameter of 3.0 mm on the permanent mask resist of the above test piece, the mold underfill was placed in a direction parallel to the test piece. The fill was scratched and the state of the test piece surface after the mold underfill was peeled off was observed. Judgment was made based on the following criteria.
A: Because the underfill and resist were in close contact with each other with high strength, there was no resist in the peeled part, and the copper foil surface of the test piece material was deposited.
B: Although the adhesion between the underfill and the resist was excellent, some of the resist remained in the peeled area.
C: Due to poor adhesion between the underfill and the resist, the resist remained completely in the peeled area.

[Solder heat resistance]
A water-soluble flux was applied to the test piece, and the test piece was immersed in a solder bath at 265°C for 10 seconds. After repeating this for 6 cycles, the appearance of the permanent mask resist was visually observed and evaluated based on the following criteria.
A: There was no change in appearance within the permanent mask resist 30 cm x 30 cm.
B: One to five flakes or blisters of the coating film occurred within a 30 cm x 30 cm permanent mask resist.
C: Six or more flakes or blisters of the coating film occurred within a 30 cm x 30 cm permanent mask resist.

[Solvent resistance]
The test piece was immersed in isopropyl alcohol at room temperature (25° C., hereinafter the same) for 30 minutes, and after checking whether there was any abnormality in the appearance of the permanent mask resist, a peeling test was carried out using cellophane tape.
A: The appearance of the permanent mask resist was normal and no peeling occurred.
B: Only a slight change occurred in the appearance of the permanent mask resist.
C: The appearance of the permanent mask resist was abnormal or peeling occurred.

[Acid resistance]
The test piece was immersed in a 10% by weight aqueous hydrochloric acid solution at room temperature for 30 minutes, and after checking whether there was any abnormality in the appearance of the permanent mask resist, a peeling test was carried out using cellophane tape.
A: The appearance of the permanent mask resist was normal and no peeling occurred.
B: Only slight change in permanent mask resist appearance occurred.
C: The appearance of the permanent mask resist was abnormal or peeling occurred.

[Alkaline resistance]
The test piece was immersed in a 5% by mass aqueous solution of sodium hydroxide at room temperature for 30 minutes, and after checking whether there was any abnormality in the appearance of the permanent mask resist, a peeling test was carried out using cellophane tape.
A: The appearance of the permanent mask resist was normal and no peeling occurred.
B: Only slight change in permanent mask resist appearance occurred.
C: The appearance of the permanent mask resist was abnormal or peeling occurred.

[Insulation properties (electrical insulation properties)]
A test piece was prepared in the same manner as described in the above [Preparation of Test Piece], except that a bismaleimide triazine substrate on which comb-shaped electrodes (line/space = 10 μm/10 μm) were formed was used instead of the copper-clad laminate substrate, and this was exposed to conditions of 135° C., 85%, and 5 V. Thereafter, the degree of occurrence of migration was observed with a metallurgical microscope at 100x magnification, and evaluated according to the following criteria.
A: Even after 200 hours, migration did not occur in the permanent mask resist, and the resistance did not decrease to 10 ⁻⁶ Ω or less.
B: 100 hours or more and less than 200 hours, no migration occurred in the permanent mask resist, and the resistance value did not decrease to 10 ⁻⁶ Ω or less.
C: Migration occurred in the permanent mask resist within 100 hours, and the resistance value decreased to 10 ⁻⁶ Ω or less.

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

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

[Photosensitive element evaluation]
The protective film was peeled off from the above photosensitive element, the photosensitive layer of the photosensitive element was thermally laminated onto a solid copper foil substrate, and then exposed in the same manner as described in [Preparation of test piece] above to form a permanent mask resist. A test piece having the following properties was prepared.

Evaluations similar to those in Example 1 were performed using the obtained test pieces. The results are shown in Table 3.

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

1...photosensitive element, 10...support film, 20...photosensitive layer, 30...protective film.

Claims (8)

(A) an acid-modified vinyl group-containing epoxy resin, (B) an epoxy compound, (C) a photopolymerization initiator, and (D) a photopolymerizable compound,
an equivalent ratio of an epoxy group contained in the epoxy compound (B) to a carboxyl group contained in the acid-modified vinyl group-containing epoxy resin (A) is 1.2 to 4.0;
does not contain any resin containing a carboxy group other than the (A) acid-modified vinyl group-containing epoxy resin,
The acid-modified vinyl group-containing epoxy resin (A) comprises an acid-modified vinyl group-containing epoxy resin (A1) which is an addition reaction product obtained by adding a saturated or unsaturated polybasic acid anhydride to an esterification product of a bisphenol novolac type epoxy resin having a structural unit represented by the following general formula (I) or (II) and a vinyl group-containing monocarboxylic acid, and an acid-modified vinyl group-containing epoxy resin (A2) which is an addition reaction product obtained by adding a saturated or unsaturated polybasic acid anhydride to an esterification product of at least one epoxy resin selected from the group consisting of a novolac type epoxy resin having a structural unit represented by the following general formula (III) and a bisphenol A type epoxy resin or a bisphenol F type epoxy resin having a structural unit represented by the following general formula (IV) and a vinyl group- containing monocarboxylic acid,
The epoxy compound (B) comprises at least one epoxy resin selected from the group consisting of bisphenol A type epoxy resins, bisphenol F type epoxy resins, and biphenyl type epoxy resins .

[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, and 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 ¹² may be the same or different, and Y ³ and Y ⁴ each independently represent a hydrogen atom or a glycidyl group, and at least one of Y ³ and Y ⁴ is a glycidyl group.]

[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 ^14s may be the same or different, and Y ⁶ represents a hydrogen atom or a glycidyl group.] The photosensitive resin composition according to claim 1 , wherein the photopolymerization initiator (C) includes an acylphosphine oxide photopolymerization initiator. The photosensitive resin composition according to claim 1 or 2 , further comprising (E) a pigment. The photosensitive resin composition according to any one of claims 1 to 3 , further comprising (F) 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 4 . A printed wiring board comprising a permanent mask resist formed from the photosensitive resin composition according to any one of claims 1 to 4 . The printed wiring board according to claim 6 , wherein the thickness of the permanent mask resist is 10 to 50 μm. forming a photosensitive layer on the substrate using the photosensitive resin composition according to any one of claims 1 to 4 or the photosensitive element according to claim 5 ;
exposing and developing the photosensitive layer to form a resist pattern;
curing the resist pattern to form a permanent mask resist;
A method of manufacturing a printed wiring board, including:

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