JP5415163B2 - Photosensitive resin composition - Google Patents

Description

  The present invention relates to a photosensitive resin composition. More specifically, the present invention relates to a plating resist suitable for forming fine wiring on a printed wiring board.

  In recent years, printed wiring boards used in electronic devices, communication devices, and the like have been increasingly demanded for high-density wiring and high processing speed. Accordingly, as a method of manufacturing a multilayer printed wiring board, a build-up manufacturing technique in which interlayer insulating layers are alternately stacked on a conductor layer of a circuit board has attracted attention.

  In general, for example, a semi-additive method is known as a build-up wiring forming method. As a method of forming a wiring by the semi-additive method, after electroless plating of the surface of the interlayer resin, a photosensitive resin plating resist is formed, and a pattern is formed by light development and alkali development with a weak alkaline aqueous solution. Next, electrolytic plating is performed to form a conductor layer, and then the plating resist is swelled and peeled off with a strong alkaline aqueous solution to remove unnecessary plating resist. After that, the wiring pattern is formed by etching the electroless plating of the non-wiring pattern portion.

  As the plating resist used in the semi-additive method, a negative photosensitive resin comprising a polyfunctional acrylic monomer, a carboxyl group-containing hydrophilic polymer, and a radical photopolymerization initiator is used. The light irradiated part is insolubilized by crosslinking and curing of the acrylic group by photo radical polymerization, and the unirradiated part is formed into a pattern by dissolving in a weak alkali with a hydrophilic polymer. Further, the resin at the photocured portion after pattern formation is peeled off by swelling the resin portion with a strong alkaline aqueous solution and further spraying.

However, as the wiring pattern becomes finer, the influence of the swelling of the pattern due to the swelling of the light-irradiated part in alkali development becomes larger, and the adhesion to the substrate is lowered by this swelling. It is necessary to suppress swelling of the resist. However, the suppression of swelling during the alkali development of the plating resist and the swelling peelability by the strong alkaline aqueous solution are contradictory, and it is difficult to achieve both.
Further, since the photo-cured plating resist between the fine wirings is difficult to peel and remove, there is a problem that a wiring pattern defect occurs due to defective removal.
For this reason, in order to form a fine wiring pattern, a plating resist having good resolution of the plating resist after alkali development and easy removal of the photocured plating resist under the condition of a strong alkaline aqueous solution is required.

As a method for easily removing the photocured plating resist with a strong alkaline aqueous solution, for example, a method of increasing the carboxyl group ratio of the hydrophilic resin to increase the hydrophilicity (Patent Document 1) has been proposed.
However, the method of increasing the hydrophilicity has a problem that the resolution is lowered because it swells even by alkali development after light irradiation.

As a method for achieving both the resolution of the plating resist and the removability by the strong alkaline aqueous solution, for example, a method for making the alkaline aqueous solution easily penetrated by heat treatment (Patent Document 2) has been proposed.
However, since it is thermally decomposed by a strong acid by an acid generator, there is a problem that the wiring copper is corroded by a strong acid.

  Accordingly, there is a need for a plating resist that has good resolution of the plating resist, can easily remove the photocured plating resist under the condition of a strong alkaline aqueous solution, and does not corrode the wiring.

JP-A-9-325487 Republished patent WO2005 / 022260 specification

  An object of the present invention is to provide a plating resist having a good resolution of the plating resist and capable of easily removing the photocured plating resist under the condition of a strong alkaline aqueous solution.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems.
That is, the present invention relates to a radically polymerizable compound (A) represented by the following general formula (1) and a hydrophilic polymer (B) containing two or more radically polymerizable double bonds (a) in the molecule. And a photosensitive resin composition (Q) characterized by containing a radical photopolymerization initiator (C) as an essential component and capable of forming a pattern by light irradiation and alkali development; and a plating resist using the same. .

[In the formula (1), R ¹ represents a monovalent electron-withdrawing group or a monovalent electron-withdrawing group containing an organic group. R ² represents a hydrogen atom or a monovalent organic group. R ³ and R ⁴ each independently represent a hydrogen atom, a monovalent electron-donating group, or a monovalent electron-donating group containing an organic group. R ⁵ represents a hydrogen atom or a monovalent organic group. R ⁶ represents a monovalent organic group. However, two or more radical polymerizable double bonds (a) are contained in a part of the organic groups in R ^{1 to} R ⁶ . ]

The photosensitive resin composition (Q) of the present invention can be photocured with a radical polymerizable double bond (a) by irradiation with ultraviolet rays. Furthermore, since the hydrophilic polymer (B) is contained, a pattern can be formed by alkali development with a weak alkaline aqueous solution.
In addition, the photocured part is cross-linked by light irradiation because the characteristic group (b) represented by the following chemical formula (10) is decomposed into a double bond-containing compound, an amine-containing compound and carbon dioxide by a strong alkaline aqueous solution. Can be disassembled. This makes it easier for the aqueous alkali solution to penetrate, and the peelability is improved.
For this reason, when used as a plating resist, it is possible to obtain excellent resolution by forming a photocured portion that is difficult to swell due to alkali development, and it can be easily peeled off with a strong alkaline aqueous solution. A plating resist capable of forming is provided.

[In Formula (10), R ¹ represents a monovalent electron-withdrawing group or a monovalent electron-withdrawing group containing an organic group. ]

The present invention comprises a radically polymerizable compound (A) having a specific chemical structure, a hydrophilic polymer (B), and a radical photopolymerization initiator (C) as essential components. (Q).
And the radically polymerizable compound (A) of this invention is represented by following General formula (1), and needs to contain the 2 or more radically polymerizable double bond (a) in a molecule | numerator. Specifically, this double bond (a) is included as part of the organic group of R ^{1 to} R ⁶ .

[In the formula (1), R ¹ represents a monovalent electron-withdrawing group or a monovalent electron-withdrawing group containing an organic group. R ² represents a hydrogen atom or a monovalent organic group. R ³ and R ⁴ each independently represent a hydrogen atom, a monovalent electron-donating group, or a monovalent electron-donating group containing an organic group. R ⁵ represents a hydrogen atom or a monovalent organic group. R ⁶ represents a monovalent organic group. However, two or more radical polymerizable double bonds (a) are contained in a part of the organic groups in R ^{1 to} R ⁶ . ]

  In addition, the characteristic group (b) part represented by the following general formula (10) in the radical polymerizable compound (A) is decomposed into a double bond-containing compound, an amine-containing compound, and carbon dioxide by a strong alkaline aqueous solution. It is expected.

R ¹ in formula (10) is the same as R ¹ in formula (1) and represents a monovalent electron-withdrawing group or a monovalent electron-withdrawing group containing an organic group.

The photosensitive resin composition (Q) of the present invention is subjected to alkali development after light irradiation, whereby the light irradiated portion is insoluble in weak alkali, and the non-light irradiated portion is dissolved in weak alkali to form a pattern.
Furthermore, the photocured part crosslinked by light irradiation is characterized in that crosslinking is decomposed at the characteristic group (b) by the strong alkaline aqueous solution, and the alkaline aqueous solution permeates to easily peel off.

R ¹ which is an essential functional group for decomposing the characteristic group (b) with a strong alkaline aqueous solution is a monovalent electron-withdrawing group (r11) or a monovalent electron-withdrawing group (r12) containing an organic group. Consists of.
Here, the electron-withdrawing group in the present invention refers to a functional group having a Hammett's substituent constant (σp value) of 0.10 or more with respect to adjacent carbon atoms.

Hammett's Substituent Constant (σp Value) Hammett's rule is based on 1935 in order to quantitatively discuss the effect of substituents on the reaction or equilibrium of benzene derivatives. P. This is an empirical rule proposed by Hammett and is widely accepted today.
Substituent constants determined by Hammett's rule include a σp value and a σm value, and these values can be found in many general books. A. Dean, “Lange's Handbook of Chemistry”, 12th edition, 1979 (McGraw-Hill) and “Chemicals” special edition, 122, 96-103, 1979 (Nankodo).
In the present invention, the Hammett's substituent constant σp of each substituent is not limited to only those substituents whose values are known in the above-mentioned book, but their values are unknown. Also includes substituents that are assumed to fall within that range when measured based on Hammett's law.
In the present invention, the σp value is used in this sense, and in the case of quantification, for example, in the case of σp ₁ (or σp ₂ ), R bonded to the carbon atom [C _a ] of the following general formula (11) ¹ (or R ² ) is calculated from a structure composed of a range of 3 atoms or less from the atoms in ¹
Further, in the case of σp ₃ (or σp ₄ ), from a structure constituted by a range of 3 atoms or less from the atoms in R ³ (or R ⁴ ) bonded to the carbon atom [C _b ] in the formula (11). calculate.

[R ^{1 to} R ⁶ in Formula (11) represent the same substituent as R ^{1 to} R ⁶ in Formula (1) above. ]

Examples of the monovalent electron-withdrawing group (r11) in R ¹ include a cyano group (—CN), a nitro group (—NO ₂ ), a nitroso group (—N═O), and a trifluoro group (—CF ₃ ). , Trialkylamine group (—N ⁺ R ₃ ), chlorine atom (—Cl), bromine atom (—Br), iodine atom (—I) and the like. Among these, a cyano group, a nitro group, and a trifluoro group are preferable from the viewpoint of decomposability in a strong alkaline aqueous solution.

Examples of the monovalent electron-withdrawing group (r12) containing an organic group in R ¹ include substituents represented by the following general formulas (2) to (9).

[R in Formulas (2) to (9) represents a monovalent organic group (ry1). ]

  Of these electron withdrawing groups (r12), from the viewpoint of ease of synthesis and decomposability in the formation of a strong alkaline aqueous solution, the substituents represented by the general formulas (2) to (7) are preferable. The substituent of (7) is more preferable.

The monovalent organic group in R ¹ (ry1), is not particularly limited, for example, an alkyl group (methyl group having 1 to 20 carbon atoms, an ethyl group, a propyl group, n- butyl group, t- butyl group ), A monovalent hydrocarbon group such as a cycloalkyl group having 4 to 20 carbon atoms (such as a cyclopentyl group or a cyclohexyl group), an aryl group having 6 to 20 carbon atoms, an arylalkyl group having 7 to 15 carbon atoms, or a part thereof Are the above hydrocarbon groups substituted with ether, ester, ketone, amino group, amide group or radical polymerizable double bond (a).

R ² in the general formula (1) is a hydrogen atom or a monovalent organic group (ry2).
As the monovalent organic group (ry2), the same one as the monovalent organic group (ry1) can be used. Preferably, when the monovalent organic group (ry2) is an electron withdrawing group, the decomposability of the characteristic group (b) is further increased.

In the radical polymerizable compound (A), R ³ and R ⁴ are each independently a hydrogen atom, a monovalent electron donating group (r31), or a monovalent electron donating group (r32) containing an organic group. Become.
Here, the electron donating group in the present invention refers to a functional group having a Hammett's substituent constant (σp value) of −0.05 or less with respect to a carbon atom bonded adjacently.

The monovalent electron donating group (r31) in R ³ and R ⁴ is, for example, an alkyl group having 1 to 12 carbon atoms (methyl group, ethyl group, propyl group, n-butyl group, t-butyl group, etc.) , A cycloalkyl group having 4 to 10 carbon atoms (such as a cyclopentyl group and a cyclohexyl group), an amino group (—NH ₂ ), a hydroxyl group (—OH), and a thiol group (—SH).

Examples of the monovalent electron donating group (r32) containing an organic group in R ³ and R ⁴ include substituents represented by the following general formulas (12) to (21).

[R in the formulas (12) to (21) represents a monovalent organic group (ry3), and R ′ represents an alkyl group having 1 to 6 carbon atoms. ]

  As the monovalent organic group (ry3), the same as the monovalent organic group (ry1) can be used.

The combination of R ¹ , R ² , R ³ and R ⁴ in the radically polymerizable compound (A) of the present invention is such that RX defined by the following formula (1) is usually 0.2 to 2.0. It is in the range, preferably 0.3 to 1.8, more preferably 0.4 to 1.6, and particularly preferably 0.5 to 1.4.

RX = σp ₁ + σp ₂ −σp ₃ −σp ₄ (1)
[Σp ₁ , σp ₂ , σp ₃ , and σp ₄ represent Hammett's substituent constants (σp values) of R ¹ , R ² , R ³ , and R ⁴ , respectively. ]

  If RX is 0.2 or more, the characteristic group (b) can be easily decomposed with a strong alkaline aqueous solution, and if it is 2.0 or less, the characteristic group (b) in alkali development with a weak alkaline aqueous solution can be decomposed. Decomposition is suppressed and pattern formation is possible.

R ⁵ in the radically polymerizable compound (A) represents a hydrogen atom or a monovalent organic group (ry5), and R ⁶ represents a monovalent organic group (ry6).
Monovalent organic group R ⁵ (ry5), and the monovalent organic group ^{R 6 (ry6)} the same thing can be used as the organic group ^{R 1} (ry1). R ⁵ can be linked to R ⁶ to form a nitrogen-containing ring.
The nitrogen-containing ring can contain a plurality of heteroatoms (N, S, O, etc.) in its ring constituent atoms.

The radically polymerizable compound (A) of the present invention usually contains 1 to 100 characteristic groups (b) represented by the general formula (10) in one molecule, preferably 80 or less, more preferably Contains 50 or less.
If the number of characteristic groups (b) is one or more in one molecule, crosslinking is decomposed by a strong alkaline aqueous solution to obtain the peelability of the light irradiation part. Can be used.

As the radical polymerizable double bond (a) in the radical polymerizable compound (A) of the present invention, a vinyl group (CH ₂ ═CH—), a vinylidene group (CH ₂ ═CH <), a vinylene group (—CH = CH-) and the like.

Examples of the vinyl group include an acryl group, an acrylamide group, a vinyl ester group, a vinyl ether group, and an allyl group.
Examples of the vinylidene group include a methacryl group, a methacrylamide group, a cyanoacryl group, and the like.
As a vinylene group, a propenyl ether group, a maleic acid group, a maleimide group etc. are mentioned, for example.
Among these, an acrylic group, an acrylamide group, an allyl group, a methacryl group, a methacrylamide group, and an allyl group are preferable from the viewpoints of reactivity and storage stability.

The radically polymerizable compound (A) of the present invention usually contains 2 to 20 double bonds (a) in one molecule, preferably 15 or less, more preferably 10 or less.
If the number of double bonds (a) is 2 or more in one molecule, sufficient cross-linking is formed by light irradiation to obtain pattern strength, and if it is 20 or less, cross-linking is sufficiently decomposed by strong alkali treatment. Peel off.

From the viewpoint of decomposition in a strong alkaline aqueous solution, the radical polymerizable compound (A) of the present invention is
Usually, one or more characteristic groups (b) that are decomposed by a strong alkaline aqueous solution are contained in one molecule, and some of the organic groups in R ^{1 to} R ⁶ in the formula (1) are radically polymerizable. It is a structure containing two or more double bonds (a).
Preferably, R ¹ or R ² in the radical polymerizable compound (A) contains one or more double bonds (a), and R ⁶ contains one or more double bonds (a). Structure (i) or Structure (ii) containing one or more double bonds (a) in R ³ or R ⁴ and one or more double bonds (a) in R ⁶ With these structures, the crosslinked structure can be efficiently decomposed and can be easily peeled off with an alkaline aqueous solution.
More preferably, the structure always includes the characteristic group (b) between the two double bonds (a). With this structure, the crosslinked structure can be completely decomposed and dissolved.

The molecular weight of the radically polymerizable compound (A) of the present invention is usually 200 to 10,000 or less, preferably 250 to 8,000, and more preferably 300 to 6,000, from the viewpoint of developability.
When the molecular weight exceeds 200, the resin hardness can be sufficiently exerted, and when the molecular weight is 10,000 or less, the developability can be satisfactorily exhibited.

The content of the radically polymerizable compound (A) based on the weight of the solid content of the photosensitive resin composition (Q) is preferably 10 to 90% by weight, more preferably 15 to 85% by weight, particularly preferably 20 to 80%. % By weight.
If it is 10% by weight or more, the photo-curing reactivity can be further improved, and if it is 90% by weight or less, the resolution can be further improved.

  Representative examples of the radical polymerizable compound of the present invention are shown below.

The photosensitive resin composition (Q) is essentially composed of the hydrophilic polymer (B) because the light-irradiated part is alkali-developed with a weak alkaline aqueous solution.
The hydrophilicity index in the hydrophilic polymer (B) in the present invention is defined by HLB. Generally, the larger this value, the higher the hydrophilicity.

The preferred range of the HLB value of the hydrophilic polymer (B) varies depending on the resin skeleton of the hydrophilic polymer (B) (for example, vinyl resin, epoxy resin, polyester resin, etc.), but preferably 4-19, Preferably it is 5-18, Most preferably, it is 6-17.
When it is 4 or more, the developing property is further improved when developing the photo spacer, and when it is 19 or less, the water resistance of the cured product is further improved.

In addition, HLB in this invention is an HLB value by the Oda method, is a hydrophilicity-hydrophobicity balance value, and can be calculated from the ratio of the organic value and inorganic value of an organic compound.
HLB≈10 × inorganic / organic In addition, the inorganic value and the organic value are described on page 501 of the document “Synthesis of Surfactant and its Application” (published by Tsuji Shoten, written by Oda, Teramura); It is described in detail on page 198 of “Introduction to New Surfactants” (Takehiko Fujimoto, published by Sanyo Chemical Industries, Ltd.).

The hydrophilic polymer (B) preferably has a carboxyl group from the viewpoint of developability. The carboxyl group content is indicated by an acid value.
The acid value of the hydrophilic polymer (B) is preferably 10 to 500 mgKOH / g. If it is 10 mgKOH / g or more, the developability is more likely to be exhibited, and if it is 500 mgKOH / g or less, the water resistance of the cured product can be further improved.

The acid value of the hydrophilic polymer (B) in the present invention can be measured by an indicator titration method using an alkaline titration solution.
A specific method is as follows.
(I) About 1 g of a sample is precisely weighed and placed in an Erlenmeyer flask, and then a neutral methanol / acetone solution (a mixture of acetone and methanol at 1: 1 (volume ratio)) is added and dissolved.
(Ii) Add several drops of phenolphthalein indicator and titrate with 0.1 mol / L potassium hydroxide titration solution. The end point of neutralization is defined as the time when the indicator is slightly red for 30 seconds.
(Iii) Determine using the following equation.
Acid value (KOHmg / g) = (A × f × 5.61) / S
However, A: mL number of 0.1 mol / L potassium hydroxide titration solution f: Titer of 0.1 mol / L potassium hydroxide titration solution S: Sampling amount (g)

The number average molecular weight (hereinafter referred to as Mn) of the hydrophilic polymer (B) measured by gel permeation chromatograph (GPC) is usually 2,000 from the viewpoint of hardness and developability when it becomes a cured product. And 100,000 or less, preferably 2,500 to 80,000, and more preferably 3,000 to 50,000.
When Mn exceeds 2,000, the resin hardness can be sufficiently exerted, and when Mn is 100,000 or less, the developability can be satisfactorily exhibited.

Examples of the hydrophilic polymer (B) include vinyl polymer (B1), epoxy polymer, polyester, polyamide, polycarbonate and polyurethane.
A hydrophilic polymer (B) may be used by 1 type, and may use 2 or more types together.
Among these, the vinyl polymer (B1) is preferable from the viewpoint of the hardness of the obtained cured product and the ease of production.

  A preferred production method of the vinyl polymer (B1) includes a vinyl monomer (Ba) having a hydrophilic group (hereinafter sometimes simply referred to as (Ba)) and, if necessary, a hydrophobic group-containing vinyl monomer (Bb) (hereinafter, referred to as “Ba”). (It may be simply expressed as (Bb)).

Examples of the vinyl monomer (Ba) having a hydrophilic group include the following (Ba1) to (Ba3) vinyl monomers.
(Ba1) Carboxyl group-containing vinyl monomer:
Unsaturated monocarboxylic acids [such as (meth) acrylic acid, crotonic acid and cinnamic acid], unsaturated polyvalent (2-4 valent) carboxylic acids [such as (anhydrous) maleic acid, itaconic acid, fumaric acid and citraconic acid], Unsaturated polyvalent carboxylic acid alkyl (alkyl group having 1 to 10 carbon atoms) ester [maleic acid monoalkyl ester, fumaric acid monoalkyl ester, citraconic acid monoalkyl ester, etc.] and salts thereof [alkali metal salt (sodium salt) And potassium salts, etc.), alkaline earth metal salts (calcium salts and magnesium salts, etc.), amine salts and ammonium salts, etc.].
Among (Ba1), preferred is an unsaturated monocarboxylic acid from the viewpoint of hydrophilicity, and more preferred is (meth) acrylic acid.

(Ba2) hydroxyl group-containing vinyl monomer:
Hydroxyalkyl (meth) acrylate [2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, etc.], polyalkylene glycol mono (meth) acrylate [polyethylene glycol mono (meta ) Acrylate etc.], alkylol (meth) acrylamide [N-methylol (meth) acrylamide etc.], hydroxystyrene and 2-hydroxyethylpropenyl ether.
Among (Ba2), hydroxyalkyl (meth) acrylate, particularly 2-hydroxyethyl (meth) acrylate is preferable from the viewpoint of alkali developability.

(Ba3) Sulphonic acid group-containing vinyl monomer:
Examples thereof include vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, α-methyl styrene sulfonic acid, 2- (meth) acryloylamido-2-methylpropane sulfonic acid, and salts thereof. Examples of the salt include alkali metal (sodium and potassium) salts, alkaline earth metal (calcium and magnesium) salts, primary to tertiary amine salts, ammonium salts and quaternary ammonium salts.

  Among these (Ba), (Ba1) and (Ba2) are preferable from the viewpoint of imparting sufficient developability, and particularly (Ba1).

  Examples of the hydrophobic group-containing vinyl monomer (Bb) include the following nonionic monomers (Bb1) to (Bb3).

(Bb1) (meth) acrylic acid ester;
C1-C20 alkyl (meth) acrylate of an alkyl group [for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, n-hexyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, etc.] and alicyclic group-containing (meth) acrylate [dicyclopentanyl (meth) acrylate, sidiclopentenyl (meth) acrylate, isobornyl (meth) acrylate, etc. ] Etc. are mentioned.

(Bb2) aromatic hydrocarbon monomer;
And hydrocarbon monomers having a styrene skeleton [for example, styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene, butylstyrene, phenylstyrene, cyclohexylstyrene, and benzylstyrene] and vinylnaphthalene. It is done.

(Bb3) carboxylic acid vinyl ester;
Examples thereof include those having 4 to 50 carbon atoms, such as vinyl acetate, vinyl propionate and vinyl butyrate.

  Of these hydrophobic group-containing vinyl monomers (Bb), (Bb1) is preferred from the viewpoint of polymerizability.

  The charged monomer molar ratio of (Ba) / (Bb) in the hydrophilic polymer (B1) is usually from 10 to 100/0 to 90, and preferably from 10 to 80/20 to 90 from the viewpoint of photocuring reactivity and developability. More preferably, it is 25-85 / 15-75.

The hydrophilic polymer (B) may contain a double bond (a) in the side chain for the purpose of further improving photocuring reactivity. The double bond (a) in the hydrophilic polymer (B) is preferably contained in 1-10 molecules, more preferably 2-5 in one molecule.
If the number of double bonds (a) is one or more in one molecule, sufficient cross-linking is formed by light irradiation to obtain a pattern strength. If the number of double bonds (a) is 10 or less, it can be sufficiently decomposed and peeled off.

The content of the hydrophilic polymer (B) based on the weight of the solid content of the photosensitive resin composition (Q) is preferably 10 to 90% by weight, more preferably 15 to 85% by weight, particularly preferably 20 to 80% by weight. %.
If it is 10% by weight or more, the alkali developability can be exhibited more satisfactorily, and if it is 90% by weight or less, the resolution can be exhibited more satisfactorily.

  In order to cause radical polymerization reaction of the double bond (a) in the radical polymerizable compound (A), the photosensitive resin composition (Q) contains the photo radical polymerization initiator (C) as an essential component.

Examples of the photo radical polymerization initiator (C) include benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzophenone, methyl benzoyl formate, isopropyl thioxanthone, 4,4-bis (dimethylamino) benzophenone, 3,3-dimethyl-4-methoxy-benzophenone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, tert-butylanthraquinone, benzoin, benzoin methyl ether, benzoin ethyl ether, Benzoinpropyl ether, acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-hydroxy-2-methylpropion Non, 4-isopropyl-2-hydroxy-2-methylpropiophenone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone, 2-chlorothioxanthone, diethylthioxanthone, isopropylthioxanthone , Diisopropylthioxanthone, Michler's ketone, benzyl-2,4,6- (trihalomethyl) triazine, 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer, 9-phenylacridine, 1,7-bis (9 -Acridinyl) heptane, 1,5-bis (9-acridinyl) pentane, 1,3-bis (9-acridinyl) propane, dimethylbenzyl ketal, trimethylbenzoyldiphenylphosphine oxide, tribromomethylphenylsulfone and 2-ben Le 2-dimethylamino-1- (4-morpholinophenyl) - butan-1-one, and the like.
The radical photopolymerization initiator (C) may be used alone or in combination of two or more.

  As the radical photopolymerization initiator (C), a commercially available product can be easily obtained. For example, as 2-methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone, Irgacure 907 is available. Examples of 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one include Irgacure 369 (manufactured by Ciba Specialty Chemicals).

The content of the radical photopolymerization initiator (C) based on the weight of the solid content of the photosensitive resin composition (Q) is preferably 0.001 to 10% by weight, more preferably 0.01 to 7% by weight, particularly Preferably it is 0.05-5 weight%.
If it is 0.001% by weight or more, the photocuring reactivity can be exhibited more satisfactorily, and if it is 10% by weight or less, the resolution can be further improved.

In order to improve adhesion to smooth electroless copper plating and to easily decompose the cross-linking with a strong alkaline aqueous solution, the photosensitive resin composition (Q) contains a plurality of thiol groups in one molecule. A functional thiol compound (D) may be contained.
By including the polyfunctional thiol compound (D), it is not a chain polymerization of the double bond (a) of the radical polymerizable compound (A), but an addition reaction between the double bond (a) and the thiol group. Since the cross-linked structure can be decomposed into low molecules by decomposing the characteristic group (b) with an alkaline aqueous solution, it can be easily peeled off with a strong alkaline aqueous solution and further dissolved in an alkali.

  Examples of the polyfunctional thiol compound (D) include bifunctional thiol (D1), trifunctional thiol (D2), and tetrafunctional or higher thiol (D3). A polyfunctional thiol compound (D) may be used individually by 1 type, and may use 2 or more types together.

  Examples of the bifunctional thiol (D1) include 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1,5-pentanedithiol, 1,6- Hexanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 2,3-dimercapto-1-propanol, dithioerythritol, 2,3-dimercaptosuccinic acid, 1,2-benzenedithiol, 1,2- Benzenedimethanethiol, 1,3-benzenedithiol, 1,3-benzenedimethanethiol, 1,4-benzenedimethanethiol, 3,4-dimercaptotoluene, 4-chloro-1,3-benzenedithiol, 2 , 4,6-trimethyl-1,3-benzenedimethanethiol, 4,4'-thiodiphenol, Hexylamino-4,6-dimercapto-1,3,5-triazine, 2-diethylamino-4,6-dimercapto-1,3,5-triazine, 2-cyclohexylamino-4,6-dimercapto-1,3 5-triazine, 2-di-n-butylamino-4,6-dimercapto-1,3,5-triazine, ethylene glycol bis (3-mercaptopropionate), butanediol bisthioglycolate, ethylene glycol bisthio 2 such as glycolate, 2,5-dimercapto-1,3,4-thiadiazole, 2,2 ′-(ethylenedithio) diethanethiol, 2,2-bis (2-hydroxy-3-mercaptopropoxyphenylpropane) And compounds having one thiol group.

  Examples of the trifunctional thiol (D2) include 1,2,6-hexanetriol trithioglycolate, 1,3,5-trithiocyanuric acid, trimethylolpropane tris (3-mercaptopropionate), trimethylolpropane tris. Examples thereof include compounds having three thiol groups such as thioglycolate and tris [(3-mercaptopropionyloxy) -ethyl] isocyanurate.

  Examples of the tetrafunctional or higher thiol (D3) include four or more such as pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakisthioglycolate, dipentaerythritol hexakis (3-mercaptopropionate), and the like. And a compound having a thiol group.

  Of these, trifunctional thiol (D2) and tetrafunctional or higher thiol (D3) are preferred from the viewpoints of photocurability and degradability.

The polyfunctional thiol compound (D) usually contains 2 to 10 thiol groups in one molecule. Preferably it is 9 or less, more preferably 8 or less, particularly preferably 6 or less.
When it is 2 or more, a sufficient cross-linked structure is formed by ene-thiol reaction with the double bond (a) of the radical polymerizable compound (A) by light irradiation, and the pattern strength is obtained, and it is 10 or less. The cross-linked structure can be easily decomposed with a strong alkaline aqueous solution, and can be peeled off with a strong alkaline aqueous solution.

The content of the polyfunctional thiol compound (D) based on the weight of the solid content of the photosensitive resin composition (Q) is usually 0.1 to 60% by weight, preferably 1 to 50% by weight, particularly preferably 2 to 40%. % By weight.
If the polyfunctional thiol compound (D) is 0.1% by weight or more, the adhesiveness with the electroless copper plating is excellent, and if it is 60% by weight or less, the pattern strength of the cured product is excellent.

The molar ratio (Am / Dm) of the number of moles (Am) of the double bond (a) in the radical polymerizable compound (A) of the present invention to the number of moles (Dm) of the thiol group in the polyfunctional thiol compound (D) Is usually 0.3 to 1.7, preferably 0.5 to 1.5, more preferably 0.7 to 1.3.
If it is in the range of 0.3 to 1.7, a sufficient cross-linked structure can be formed to obtain pattern strength, and the cross-linked structure can be easily decomposed and peeled off with a strong alkaline aqueous solution. can do.

The photosensitive resin composition (Q) may contain a basic compound (E) in order to release the light-irradiated part with a weak alkaline aqueous solution instead of a strong alkaline aqueous solution.
By containing the basic compound (E), the characteristic group (b) can be decomposed by the same reaction as the decomposition with the strong alkaline aqueous solution by heat-treating the light irradiation part. Thereby, a crosslinked structure can be decomposed | disassembled and a peeling process is attained also with weak alkaline aqueous solution.

Examples of the basic compound (E) include primary and secondary amines, imidazoles, tertiary amines, and photobase generators.
As the primary or secondary amine, an aromatic amine compound, an aliphatic amine compound, an alicyclic amine compound, or the like is used.
Known aromatic amine compounds can be used, such as 1,3-phenylenediamine, 1,4-phenylenediamine, 4,4′-diphenylmethanediamine, 4,4′-diaminodiphenylmethane, 4,4′-diamino. Examples include diphenyl ether, 3,3′-dimethyl-4,4′-diaminodiphenyl ether, 4,4′-diaminobenzophenone, and 4,4′-diaminodiphenyl sulfone.

  As the aliphatic amine compound, known compounds can be used, such as ethylenediamine, propylenediamine, trimethylenediamine, diethylenetriamine, iminobispropylamine, and 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane. Can be mentioned.

  As the alicyclic amine compound, known compounds can be used, such as cyclohexylene-1,3-diamine (an aromatic nucleus hydrogenated compound of 1,3-phenylenediamine), cyclohexylene-1,4-diamine (1,4 -Phenylenediamine aromatic nucleus hydrogenated compound), bis (aminocyclohexyl) methane (4,4'-diphenylmethanediamine aromatic nucleus hydrogenated compound) and the like.

  As the imidazole, known ones can be used, for example, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzyl-2- Examples include methylimidazole and 1-cyanoethyl-2-methylimidazole.

  As the tertiary amine, known ones can be used. For example, benzylmethylamine, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (diaminomethyl) phenol, triethylamine, 1,5-diazabicyclo [ 4,3,0] -5-Nonene (Trademark: DBA), 1,8-diazabicyclo [5,4,0] -7-undecene (Trademark: DBU), DBU-phenol salt, DBU-octyl And acid salts, DBU-p-toluenesulfonate, DBN-phenol salt, DBN-octylate, DBN-p-toluenesulfonate, and the like.

  Examples of the photobase generator include ammonium metal salt compounds (Japanese Patent Laid-Open No. Sho 56-57859), carbamoyloxime compounds, carbamoylhydroxylamine compounds, carbamic acid compounds, formamide compounds, acetamide compounds, carbamate compounds, benzylcarbamate compounds, nitrobenzyl. Carbamate compounds, sulfonamide compounds, imidazole derivative compounds, amine imide compounds, pyridine derivative compounds, α-aminoacetophenone derivative compounds, quaternary ammonium salt derivative compounds, α-lactone ring derivative compounds, amine imide compounds, phthalimide derivative compounds, and the like.

  Among these basic compounds (E), from the viewpoint of storage stability, imidazole, tertiary amine, and photobase generator are preferable, and tertiary amine salt and photobase generator are more preferable. It is.

The content of the basic compound (E) based on the weight of the solid content of the photosensitive resin composition (Q) is preferably 0.001 to 15% by weight, more preferably 0.01 to 10% by weight, particularly preferably. 0.05 to 7% by weight.
If it is 0.001% by weight or more, the decomposition reactivity during heating of the characteristic group (b) can be exhibited more favorably, and if it is 15% by weight or less, the physical properties of the cured product can be exhibited more favorably.

The photosensitive resin composition (Q) may further contain other components (F) as necessary.
As other components (F), inorganic fine particles (F1), sensitizers (F2), polymerization inhibitors (F3), and other additives (for example, inorganic pigments, silane coupling agents, dyes, fluorescent brighteners) , Yellowing inhibitors, antioxidants, antifoaming agents, etc.).

As the inorganic fine particles (F1), metal oxides and metal salts can be used.
Examples of the metal oxide include titanium oxide, silicon oxide, and aluminum oxide.

Examples of the metal salt include calcium carbonate and barium sulfate.
Of these, metal oxides are preferable from the viewpoint of heat resistance and chemical resistance, and silicon oxide and titanium oxide, and particularly silicon oxide are more preferable.
The inorganic fine particles have a volume average primary particle diameter of 1 to 200 nm, preferably from 1 to 150 nm, more preferably from 1 to 120 nm, and particularly preferably from 5 to 20 nm, from the viewpoint of transparency.

  The content of (F1) based on the weight of the solid content of the photosensitive resin composition (Q) is usually 0 to 50% by weight, preferably 1 to 45% by weight, particularly preferably 2 to 40% by weight. If it is 50% by weight or less, the developability can be further improved.

  Examples of the sensitizer (F2) include nitro compounds (for example, anthraquinone, 1,2-naphthoquinone, 1,4-naphthoquinone, benzanthrone, p, p′-tetramethyldiaminobenzophenone, carbonyl compounds such as chloranil, nitrobenzene, p -Dinitrobenzene and 2-nitrofluorene etc.), aromatic hydrocarbons (eg anthracene and chrysene etc.), sulfur compounds (eg diphenyl disulfide etc.) and nitrogen compounds (eg nitroaniline, 2-chloro-4-nitroaniline) , 5-nitro-2-aminotoluene, tetracyanoethylene and the like.

  The content of the sensitizer (F2) based on the weight of the radical photopolymerization initiator (C) is usually 0.1 to 100% by weight, preferably 0.5 to 80% by weight, particularly preferably 1 to 70% by weight. It is.

  There is no limitation in particular as a polymerization inhibitor (F3), What is used for normal reaction is used. Specifically, diphenylhydrazyl, tri-p-nitrophenylmethyl, N- (3-N-oxyanilino-1,3-dimethylbutylidene) aniline oxide, p-benzoquinone, p-tert-butylcatechol, nitrobenzene, Examples include picric acid, dithiobenzoyl disulfide, and copper (II) chloride.

  The content of the polymerization inhibitor (F3) based on the weight of the solid content of the photosensitive resin composition (Q) is preferably 0 to 1.0% by weight, more preferably 0.01 to 0.5% by weight, particularly. Preferably it is 0.02 to 0.1 weight%.

As a method for forming the plating resist (R) of the present invention,
(1) Curtain coating, roll coating, spray coating, screen printing with photosensitive resin varnish (QW) in which photosensitive resin composition (Q) is dissolved in a predetermined organic solvent (dissolved and dispersed when inorganic fine particles are included) A method of forming a plating resist (R) by drying the solvent by heating or hot air blowing after applying to the substrate using a known method such as; and (2) the resin varnish (QW) on the supporting base film. A plating resist film (RF) having a photosensitive resin layer formed by applying and drying using the same method is subjected to pressure laminating on a substrate under heating conditions to form a plating resist (R). The method etc. are mentioned.
A preferred method is a method in which a plating resist film (RF) is pressure-laminated under heating conditions. This is preferable because the productivity of the printed wiring board is greatly improved.

The organic solvent for dissolving the photosensitive resin composition (Q) is not particularly limited as long as the resin composition can be dissolved and the resin solution can be adjusted to physical properties (viscosity, etc.) applicable to a film production apparatus. . For example, known solvents such as N-methylpyrrolidone, N, N-dimethylformamide, dimethyl sulfoxide, toluene, ethanol, cyclohexanone, methanol, methyl ethyl ketone, ethyl acetate, acetone and xylene can be used.
Of these solvents, those having a boiling point of 200 ° C. or less (toluene, ethanol, cyclohexanone, methanol, methyl ethyl ketone, ethyl acetate, acetone and xylene) are preferable from the viewpoint of the drying temperature of the film, etc., alone or in combination of two or more. It can also be used.
When the organic solvent is used, the amount of the solvent is not particularly limited, but is usually preferably 30 to 1,000% by weight, more preferably 40 based on the weight of the solid content of the photosensitive resin composition (Q). It is -900 weight%, Most preferably, it is 50-800 weight%.

The resin varnish (QW) of the photosensitive resin composition (Q) can be obtained, for example, by mixing each component with a known mixing device such as a planetary mixer.
The resin varnish (QW) is usually liquid at room temperature and has a viscosity of 0.1 to 10,000 mPa · s, preferably 1 to 8,000 mPa · s at 25 ° C.

  The drying conditions of the resin varnish (QW) vary depending on the solvent to be used, but it is preferably carried out at 50 to 200 ° C. for 2 to 30 minutes. The complex viscosity of the photosensitive resin composition (Q) after drying and the amount of residual solvent (Wt%) and the like are determined as appropriate.

As a substrate, an interlayer insulating resin layer is formed on a copper-clad laminate, an electroless plating or electrolytic plating layer is further formed on the surface of the interlayer insulating resin, and an electroless plating catalyst is applied to the surface of the interlayer insulating resin. Substrates are preferred.
Examples of the copper clad laminate include a glass epoxy, a metal plate, a polyester plate, a polyimide plate, a thermosetting polyphenylene ether plate, etc. bonded with a copper foil.

Examples of the supporting base film include polyolefins such as polyethylene and polyvinyl chloride, polyesters such as polyethylene terephthalate, and polycarbonate. The thickness of the base film is preferably 10 to 150 μm. The width of the base film is not particularly specified as long as it can enter the apparatus, but is preferably 30 to 300 cm.
The base film may be subjected to a mold release treatment in addition to a mat treatment and a corona treatment. Since this resin composition exudes resin during lamination, if a support base portion having no resin is provided at both ends or one side of the roll at least 5 mm, it is easy to prevent the resin from adhering to the laminate portion and to peel off the support base film. There are advantages such as.

When the plating resist film (RF) is pressure-laminated on the substrate under heating conditions, it is laminated while pressing and heating from the support base film side. Lamination may be performed under reduced pressure, in a batch system or a continuous system in a roll system, and it is preferable to laminate both surfaces simultaneously.
As for the lamination condition, the lamination temperature is usually 50 to 180 ° C, preferably 60 to 170 ° C, more preferably 70 to 150 ° C. If it is less than 50 ° C., it is difficult to transfer to the inner layer substrate. The pressure of the laminate is usually 0.01 to 20 MPa, preferably 0.1 to 15 MPa. If it is less than 0.01 MPa, transfer to the inner layer substrate is difficult, and if it is higher than 20 MPa, the thickness of the plating resist (R) cannot be adjusted. The decompression condition is preferably 2.5 kPa or less.

After forming the plating resist (R) on the substrate, the wiring pattern-shaped groove is formed by performing the light irradiation of the wiring pattern shape and the step (I) of alkali development. Next, electroless plating or electrolytic plating is performed to form wiring in the groove portion.
Thereafter, an alkali stripping or dissolving step (II) with a strong alkaline aqueous solution is performed to decompose the characteristic group (b) portion and remove the photocured plating resist (R). Thereafter, the wiring can be formed by etching the electroless plating or the electrolytic plating layer as necessary.

Examples of the method of irradiating with light in the step (I) include a method of exposing the plating resist (R) with actinic rays through a photomask having a wiring pattern. The actinic ray used for light irradiation is not particularly limited as long as the photosensitive resin composition (Q) of the present invention can be cured.
As active light, low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, xenon lamp, metal halogen lamp, electron beam irradiation device, X-ray irradiation device, laser (argon laser, dye laser, nitrogen laser, helium cadmium laser) Etc.). Of these, high pressure mercury lamps and ultrahigh pressure mercury lamps are preferred.

Examples of the method of alkali development in step (I) include a method of dissolving and removing the wiring pattern shape using an alkali developer. As the alkali developer, the ultraviolet ray irradiation part of the photosensitive resin composition (Q) is not dissolved, the ultraviolet ray non-irradiation part can be dissolved, and the characteristic group (b) is particularly difficult to be decomposed. There is no limit.
Examples of the alkali developer include a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, sodium hydrogen carbonate, and a tetramethylammonium salt aqueous solution.
These alkaline developers may contain a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropyl alcohol, tetrahydrofuran, and N-methylpyrrolidone.

As a developing method, there are a dip method, a shower method, and a spray method using an alkaline developer, but the spray method is more preferable.
The temperature of the developer is preferably 25 to 40 ° C. The development time is appropriately determined according to the thickness of the plating resist (R).

Examples of the method of removing or dissolving the alkali in the step (II) include a method of swelling and removing or dissolving and removing using an alkaline aqueous solution. There is no restriction | limiting in particular as aqueous alkali solution, if it is the conditions which can decompose | disassemble characteristic group (b).
Examples of the alkaline aqueous solution include a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, sodium hydrogen carbonate, and a tetramethylammonium salt aqueous solution. These alkaline aqueous solutions may contain a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropyl alcohol, tetrahydrofuran and N-methylpyrrolidone.
As a removing method, there are a dip method, a shower method, and a spray method using an alkaline aqueous solution, but the spray method is preferable. The temperature of the aqueous solution is preferably 25 to 40 ° C. The dissolution time is appropriately determined according to the thickness of the plating resist (R).

When the basic compound (E) is contained in the photosensitive resin composition (Q), a heating step for decomposing the characteristic group (b) may be performed before the step (II).
As temperature of a heating process, it is 100-200 degreeC normally, Preferably it is 110-190 degreeC, More preferably, it is 120-180 degreeC. If it is less than 100 degreeC, characteristic group (b) cannot fully decompose | disassemble, but alkali peeling or solubility is insufficient, and when it exceeds 200 degreeC, there exists a problem that productivity of a printed wiring board falls.
The heating time is usually 2 to 120 minutes, preferably 3 to 90 minutes, and more preferably 3 to 90 minutes. If it is less than 2 minutes, it is difficult to control the time and temperature.

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, unless otherwise specified, “%” represents “% by weight” and “parts” represents “parts by weight”.

<Synthesis Example 1>
<Synthesis of Radical Polymerizable Compound (A-1)>
A three-necked flask equipped with a thermometer, a stirrer, a dropping funnel and a reflux condenser was charged with 300 parts of 35% formalin and 300 parts of tetrahydrofuran, and then gradually added 430 parts of ethylene glycol monoacetate monomethacrylate, The reaction was allowed to proceed for 12 hours at ° C. Subsequently, extraction with toluene-water was performed to recover the toluene layer, and the solvent was removed under reduced pressure to obtain an alcohol compound (Aa-1).

  Subsequently, 160 parts of 1,4-phenylene diisocyanate and 400 parts of toluene were charged into a three-necked flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser, and then 244 parts of an alcohol compound (Aa-1) was gradually added. However, after reacting at 50 ° C. for 12 hours, the solvent is removed under reduced pressure, so that the chemical formula (22) contains two characteristic groups (b) and two double bonds (a) in the molecule. The represented radically polymerizable compound (A-1) was obtained. (RX = 1.04)

<Synthesis Example 2><Synthesis of Radical Polymerizable Compound (A-2)>
In a three-necked flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser, 276 parts of 1,3-bis (2-hydroxyethylsulfonyl) -2-propanol, 6 parts of dibutyltin dilaurate, and 780 parts of dimethylformamide were added. Charged and uniformly dissolved at room temperature. Next, while gradually adding 500 parts of 2-methacryloxyethyl isocyanate (“Karenz MOI”, manufactured by Showa Denko KK), the mixture was reacted at 40 ° C. for 12 hours, and then the solvent was removed under reduced pressure, whereby a characteristic group ( A radical polymerizable compound (A-2) represented by the chemical formula (27) containing 3 b) and 3 double bonds (a) was obtained. (RX = 0.73)

<Synthesis Example 3>
<Synthesis of hydrophilic polymer (B-1)>
A three-necked flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser is charged with 60 parts of isobornyl methacrylate, 20 parts of 2-hydroxyethyl methacrylate, 20 parts of methacrylic acid, and 150 parts of methyl ethyl ketone up to 80 ° C. Heated. After substituting the gas phase part in the system with nitrogen, 55 parts of a solution prepared by dissolving 5 parts of AIBN prepared in advance in 50 parts of methyl ethyl ketone was dropped into Kolben at 80 ° C. over 10 minutes, and the same temperature. For 3 hours. Thereafter, methylethylketone was removed under reduced pressure to obtain a hydrophilic polymer having a hydroxyl group and a carboxyl group (B-1: Mn: 21,000, SP value: 12.24, HLB value: 12.38, hydroxyl value: 86 mgKOH / g , Acid value: 138 mgKOH / g), a hydrophilic polymer (B-1) was obtained.

<Comparative Synthesis Example 1>
<Synthesis of Radical Polymerizable Compound (A′-1)>
In the same manner as in Synthesis Example 1 except that 130 parts of hydroxyethyl methacrylate was used instead of 244 parts of the alcohol compound (Aa-1), two characteristic groups (b ′) not containing an electron-withdrawing group were obtained. A radical polymerizable compound (A′-1) containing 2 heavy bonds (a) in the molecule was obtained. (RX <0).

<Comparative Synthesis Example 2>
<Synthesis of Radical Polymerizable Compound (A′-2)>
Radical polymerization having one characteristic group (b) and only one double bond in the molecule in the same manner as in Synthesis Example 1 except that 119 parts of phenyl isocyanate is used instead of 1,4-phenylene diisocyanate. Compound (A′-2) was obtained. (RX = 1.04).

<Example 1>
In a three-necked flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser, 45 parts of the hydrophilic polymer (B-1) synthesized in Synthesis Example 3 and 120 parts of dimethylformamide were uniformly dissolved. Next, 50 parts of the radical polymerizable compound (A-1) synthesized in Synthesis Example 1 and 5 parts of a photopolymerization initiator (C-1) (Ciba Specialty Chemicals Co., Ltd., “Irgacure 907”) were added, The mixture was stirred and dissolved at 25 ° C. to obtain a photosensitive resin varnish.

  This photosensitive resin varnish was applied to a copper-clad laminate (“CCL-HL830”, manufactured by Mitsubishi Gas Chemical Company, Inc.) having a surface roughness of 0.3 μm and subjected to microetching at a coating speed of 0.3 m / min. The whole surface was coated with a knife coater so that the thickness of the photosensitive resin layer after drying was 15 μm, and then dried at 80 ° C. for 4 minutes to form a plating resist.

  A wiring pattern having a line / space (hereinafter referred to as L / S) of 25 μm / 25 μm and 15 μm / 15 μm is formed on the formed plating resist using a projection type exposure apparatus (OMW Corporation, HMW-661F-01). It was exposed to light, developed by spraying a 1% aqueous sodium carbonate solution at 30 ° C. for 90 seconds, washed with water, blown with air, and then dried at 60 ° C. for 20 minutes in a circulating drier.

  Next, after electrolytic copper plating was performed to form a 13 μm conductor layer, it was immersed in a 3% aqueous sodium hydroxide solution at 30 ° C. for 3 minutes. Subsequently, after washing with water and air blowing, the printed wiring board (Z-1) was obtained by drying at 100 ° C. for 20 minutes in an air circulation dryer.

<Example 2>
The number of parts of the radical polymerizable compound (A-1) was changed to 30 parts, and pentaerythritol tetrakis- (3-mercaptopropionate) (“PMP” manufactured by Sakai Chemical Industry Co., Ltd.) as a polyfunctional thiol compound ( D-1) A printed wiring board (Z-2) was obtained in the same manner as in Example 1 except that 20 parts were added.

<Example 3>
A printed wiring board (Z-3) was obtained in the same manner as in Example 1 except that 50 parts of the radical polymerizable compound (A-2) was used instead of the radical polymerizable compound (A-1).

<Example 4>
A printed wiring board (Z-4) was obtained in the same manner as in Example 2 except that 30 parts of the radical polymerizable compound (A-2) was used instead of the radical polymerizable compound (A-1).

<Comparative Example 1>
A printed wiring board was prepared in the same manner as in Example 1 except that the radical polymerizable compound (A-1) was changed to 50 parts of the radical polymerizable compound (A′-1) comprising a characteristic group not containing an electron withdrawing group. (Z′-1) was obtained.

<Comparative example 2>
Printing was performed in the same manner as in Example 1 except that the radical polymerizable compound (A-1) was changed to 50 parts of the radical polymerizable compound (A′-2) containing only one radical polymerizable double bond. A wiring board (Z′-2) was obtained.

<Comparative Example 3>
Radical polymerizable compound (A-1), radical polymerizable compound (A′-3) not containing the characteristic group (b) (“Neomer DA-600” manufactured by Sanyo Chemical Industries, Ltd .; dipentaerythritol pentaacrylate and A printed wiring board (Z′-3) was obtained in the same manner as in Example 1 except that the mixture was changed to 50 parts (mixture of dipentaerythritol hexaacrylate).

<Comparative Example 4>
Printing was performed in the same manner as in Example 1 except that the radical polymerizable compound (A-1) was changed to 20 parts of the radical polymerizable compound (A′-3) and the number of parts of the hydrophilic polymer (B-1) was changed to 75 parts. A wiring board (Z′-4) was obtained.

<Performance evaluation>
As the performance evaluation of the plating resist, the obtained printed wiring boards (Z-1) to (Z-4) and (Z′-1) to (Z′-4) have a resist pattern formability, The behavior of the resist and the wiring pattern formability were evaluated by the following methods.

<Resist pattern formability>
After exposure, 1% sodium carbonate aqueous solution development and drying of the formed plating resist, L / S was 25 μm / 25 μm and 15 μm / 15 μm using a shape measuring microscope (VD-8550, manufactured by Keyence Corporation). The peeling of the 15 μm resist pattern was observed under the condition of a microscope magnification of 200 times and evaluated according to the following criteria.
○: No peeling of wiring is recognized at all ×: There is partial peeling of wiring

<Behavior of resist in strong alkaline aqueous solution>
The behavior when the resist after light irradiation was immersed in a 2% aqueous sodium hydroxide solution was visually observed and evaluated according to the following criteria.
◎: Resist dissolves ○: Resist swells and peels ×: Resist does not change

<Wiring pattern formability>
Use a shape measurement microscope to observe the presence or absence of resist residues between the wires in the plated wiring pattern with L / S of 25/25/15 and 15/15/15 μm at a magnification of 200 ×. The evaluation was made according to the following criteria.
○: Resist residue is not recognized ×: Resist residue partially

  Table 1 shows the number of blended photosensitive resins obtained in Examples and Comparative Examples and the evaluation results of the printed wiring board.

As is apparent from Table 1, when the photosensitive resin compositions (Q) of Examples 1 to 4 of the present invention are used for the plating resist, the resist pattern formability is good even when L / S is 15 μm / 15 μm, and Since the resist can be removed after plating, it can be seen that a wiring having no defect can be formed even in a wiring of 15 μm or less. In particular, Examples 2 and 4 containing the polyfunctional thiol compound (D) can be dissolved in a strong alkaline aqueous solution, and the removability of the resist is particularly excellent.
On the other hand, in Comparative Example 1 using the radically polymerizable compound (A′-1) composed of the characteristic group (b ′) not containing an electron-withdrawing group, decomposition with a strong alkaline aqueous solution does not occur. The removability is poor and there is a problem with the wiring pattern formation.
It can be seen that Comparative Example 2 using the radically polymerizable compound (A′-2) containing only one double bond (a) has a poor resist photocurability and a problem in resist pattern formation.
Further, Comparative Example 3 using a radically polymerizable compound (A′-3) not containing the characteristic group (b) and having a small amount of hydrophilic polymer has poor removability of the resist between the wirings, and has a problem in wiring pattern formability. It can be seen that Comparative Example 4 having a large amount of hydrophilic polymer swells at the time of alkali development, so that the adhesion to the copper surface is lowered and the resist pattern formability is deteriorated.

  When the photosensitive resin composition of the present invention is used as a plating resist, the resolution at the time of alkali development is excellent, and the photocured portion is easily decomposed by a strong alkaline aqueous solution, so that the removability of the plating resist between fine wirings is excellent. Therefore, it is suitable as a plating resist for forming a printed wiring board suitable for increasing the density and speed of conductor circuits.

Claims (7)

Radical polymerizable compound (A) represented by the following general formula (1) containing two or more radical polymerizable double bonds (a) in the molecule, hydrophilic polymer (B), and initiation of radical photopolymerization A photosensitive resin composition (Q) comprising an agent (C) as an essential component and capable of forming a pattern by light irradiation and alkali development.

[In the formula (1), R ¹ represents a monovalent electron-withdrawing group or a monovalent electron-withdrawing group containing an organic group. R ² represents a hydrogen atom or a monovalent organic group. R ³ and R ⁴ each independently represent a hydrogen atom, a monovalent electron-donating group, or a monovalent electron-donating group containing an organic group. R ⁵ represents a hydrogen atom or a monovalent organic group. R ⁶ represents a monovalent organic group. However, R ¹ radical polymerizable double bond in some of the organic groups in to R ^6: (a) containing 2 or more, R ³ or R ⁴ 1 or more double bonds in (a ) And one or more double bonds (a) in R ⁶ . ] The radically polymerizable compound (A) contains one or more radically polymerizable double bonds (a) in R ¹ or R ² in the general formula (1), and one or more in R ⁶ The photosensitive resin composition (Q) according to claim 1, comprising a double bond (a). RX defined by the following formula (1) using each Hammett's substituent constant (σp value) of R ¹ , R ² , R ³ and R ⁴ of the radical polymerizable compound (A) is 0.3 to 1 The photosensitive resin composition (Q) according to claim 1 or 2, which is .8.
RX = σp ₁ + σp ₂ −σp ₃ −σp ₄ (1)
In the formula, σp ₁ , σp ₂ , σp ₃ , and σp ₄ represent Hammett's substituent constants (σp values) of R ¹ , R ² , R ³ , and R ⁴ , respectively. Furthermore, the photosensitive resin composition (Q) in any one of Claims 1-3 containing the polyfunctional thiol compound (D) which contains a 2 or more thiol group in a molecule | numerator. The ratio Am / Dm of the number of moles (Am) of the double bond (a) of the radical polymerizable compound (A) to the number of moles (Dm) of the thiol group of the polyfunctional thiol compound (D) is 0.5 to 1. The photosensitive resin composition (Q) according to any one of claims 1 to 4, which is 0.5. The photosensitive resin composition (Q) according to any one of claims 1 to 5, wherein R ¹ in the radical polymerizable compound (A) is an electron-withdrawing group represented by the following general formulas (2) to (9). ).

[In the formulas (2) to (9), R represents a monovalent organic group. ] The plating resist (R) using the photosensitive resin composition (Q) in any one of Claims 1-6 .