JP2021140004A - Photosensitive resin composition for laser direct writing exposure, and photosensitive element, resist pattern forming method and method for manufacturing printed wiring board using the same - Google Patents

Abstract

To provide a photosensitive resin composition for laser direct writing exposure having high photosensitivity compatible with an LDI system, and a photosensitive element, a resist pattern formation method, and a method for manufacturing a printed wiring board using the same.SOLUTION: A photosensitive resin composition for laser direct writing exposure contains (A) a binder polymer, (B) a photopolymerizable compound, (C) a photopolymerization initiator, (D) a compound having a mercapto group and (E) a sensitizer, and contains a compound having a pyrazoline skeleton as a sensitizer of the component (E). A photosensitive element has a support, and a photosensitive layer using the photosensitive resin composition for laser direct writing exposure on the support.SELECTED DRAWING: Figure 1

Description

The present invention relates to a photosensitive resin composition for direct laser drawing exposure, a photosensitive element using the same, a method for forming a resist pattern, and a method for manufacturing a printed wiring board.

In the printed wiring board manufacturing industry, solder resist has been conventionally formed on a printed wiring board. This solder resist has a role of preventing solder from adhering to unnecessary parts of the conductor layer of the printed wiring board in the soldering process for joining the mounted parts to the printed wiring board, and also joins the mounted parts. When the printed wiring board is used later, it also has a role as a permanent mask for preventing corrosion of the conductor layer and maintaining electrical insulation between the conductor layers.

As a method for forming a solder resist, for example, a method of screen-printing a thermosetting resin on a conductor layer of a printed wiring board is known. However, since there is a limit to increasing the resolution of the resist pattern by such a method, it has become difficult to cope with the recent increase in the density of printed wiring boards.

Therefore, in order to achieve high resolution of the resist pattern, the photoresist method has been widely used. In this photoresist method, a photosensitive resin composition layer composed of a photosensitive resin composition is formed on a substrate, the photosensitive resin composition layer is cured by exposure of a predetermined pattern, and an unexposed portion is removed by development. It forms a cured film with a predetermined pattern.

Further, as the photosensitive resin composition used in such a method, an alkali-developable type that can be developed with a dilute alkaline aqueous solution such as a sodium carbonate aqueous solution has become mainstream from the viewpoint of work environment protection and global environment protection. .. As such a photosensitive resin composition, for example, the liquid resist ink composition described in Patent Document 1 below, the photosensitive thermosetting resin composition described in Patent Document 2 below, and the like are known.

Japanese Unexamined Patent Publication No. 61-243869 Japanese Unexamined Patent Publication No. 01-141904

In the field of manufacturing printed wiring boards, a photosensitive resin composition or a layer formed by using a photosensitive resin composition as a resist used for etching treatment, plating treatment, etc. in addition to the above-mentioned solder resist applications. A photosensitive element having a support (hereinafter referred to as a "photosensitive layer") is widely used. It is manufactured by the same method as the above-mentioned solder resist forming method, for example, when a photosensitive element is used, the procedure is as follows. That is, first, the photosensitive layer of the photosensitive element is laminated on a circuit-forming substrate such as a copper-clad laminate. Next, the photosensitive layer is exposed through a mask film or the like to form a photocurable portion. At this time, the support is peeled off at any timing before or after the exposure. After that, the region of the photosensitive layer other than the photocurable portion is removed with a developing solution. Next, an etching treatment or a plating treatment is performed to form a conductor pattern, and finally the photocurable portion is removed.
The photosensitive resin composition is a method of directly drawing a pattern created by CAD (computer-aided design) by laser light without requiring a mask from the viewpoint of further increasing the density of the printed wiring board, LDI (laser). A photosensitive curable resin composition compatible with the direct imaging) method is desired.

In the LDI method, a highly sensitive photosensitive resin composition is required from the viewpoint of improving throughput and the like. However, the conventional photosensitive resin compositions described in Patent Document 1 and Patent Document 2 do not have sufficient photosensitivity to be compatible with the LDI method, and it is difficult to apply them to the LDI method. .. Further, although the sensitivity can be improved by adding a large amount of a photopolymerization initiator or a sensitizer, in that case, sufficient resist characteristics tend not to be obtained.

Generally, resists have developability, high resolution, solder heat resistance, plating resistance, thermal shock resistance (crack resistance) to temperature cycle test (TCT), and ultra-accelerated high temperature and high humidity life test (HAST). ) Is required to be resistant to (HAST resistance) between fine wires. From the viewpoint of workability, it is also desired that the photosensitive resin composition has low tackiness (surface stickiness after solvent drying).

The present invention has been made in view of the above circumstances, and forms a photosensitive resin composition for laser direct drawing exposure having high light sensitivity compatible with the LDI method, and a photosensitive element and a resist pattern using the same. It is an object of the present invention to provide a method and a method for manufacturing a printed wiring board.

The present invention includes [1] (A) a binder polymer, (B) a photopolymerizable compound, (C) a photopolymerization initiator, (D) a compound having a mercapto group, and (E) a sensitizer, and (E). The present invention relates to a photosensitive resin composition for laser direct drawing exposure, which contains a compound having a pyrazoline skeleton as a component sensitizer.
Further, in the present invention, [2] for laser direct drawing exposure according to the above [1], wherein the compound having a mercapto group of the component (D) is a compound having a secondary thiol or a tertiary thiol having an imidazole skeleton. The present invention relates to a photosensitive resin composition.
Further, the present invention includes a [3] support and a photosensitive layer on the support using the photosensitive resin composition for laser direct drawing exposure according to the above [1] or [2]. Regarding the element.
Further, the present invention relates to the photosensitive resin composition for laser direct drawing exposure according to the above [1] or [2], or the photosensitive resin composition for laser direct drawing exposure according to the above [1] or [2], or the above [3] on the circuit forming substrate [4] (i). A step of forming a photosensitive layer using a photosensitive element, (ii) a step of irradiating a predetermined portion of the photosensitive layer with active light to form a photocurable portion, and (iii) a process of forming a circuit. The present invention relates to a method for forming a resist pattern, comprising a step of removing at least a part other than the photocurable portion from the photosensitive layer.
Further, the present invention comprises a step of forming a conductor pattern by etching or plating a substrate on which a resist pattern is formed by the method for forming a resist pattern according to [5] above [4]. Regarding the manufacturing method of.
Further, the present invention relates to the method for manufacturing a printed wiring board according to the above [5], further comprising a step of removing the photocured portion after the step of forming the conductor pattern [6].

When the photosensitive resin composition for laser direct drawing exposure of the present invention is used, it has high light sensitivity, can perform direct drawing exposure by the LDI method, and has high sensitivity and resistance suitable for circuit formation of a printed wiring board. A photosensitive element (dry film), resist pattern, and printed wiring board with excellent plating can be obtained.

It is a photograph which shows the cross section which formed the conductor pattern by copper plating and tin plating on the resist pattern produced in an Example. It is a figure which shows typically the cross-sectional structure of the photosensitive element which concerns on embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail. In the present invention, (meth) acrylic acid means acrylic acid and / or methacrylic acid, (meth) acrylate means acrylate and / or methacrylate, and (meth) acryloyl group means. Means an acryloyl group and / or a metaacryloyl group.

(Photosensitive resin composition for direct laser exposure)
The photosensitive resin composition for laser direct drawing exposure according to the present embodiment includes (A) a binder polymer, (B) a photopolymerizable compound, (C) a photopolymerization initiator, and (D) a compound having a mercapto group. And (E) a sensitizer is contained, and a compound having a pyrazoline skeleton is used as the sensitizer for the component (E).

<(A) Binder polymer>
The photosensitive resin composition for laser direct drawing exposure according to the present embodiment contains one or more binder polymers as the component (A).
As the binder polymer, a polymer having a carboxyl group in the molecule is preferable, for example, acrylic resin, polyurethane, vinyl group-containing epoxy resin, epoxy resin, phenoxy resin, polyester, polyamide, polyimide, polyamideimide, polyesterimide, polycarbonate, melamine. Examples thereof include known resins such as resins, polyphenylene sulfides and polyoxybenzoyls, and acid-modified resins thereof having a carboxyl group in the molecule. These can be used alone or in combination of two or more.

The photosensitive resin composition for laser direct drawing exposure according to the present embodiment preferably contains the following urethane resin (a1) as the component (A).
The urethane resin of the component (a1) has an ethylenically unsaturated group and a carboxyl group. The component (a1) has (a) an ethylenically unsaturated group and two or more hydroxyl groups from the viewpoint of further improving the photosensitivity of the photosensitive resin composition and corresponding to curing with a smaller amount of active light energy. A urethane resin (a1) obtained by reacting an epoxy acrylate compound, (b) a diisocyanate compound, and (c) a diol compound having a carboxyl group is preferable.

The epoxy acrylate compound (a) may be any epoxy acrylate compound having an ethylenically unsaturated group and two or more hydroxyl groups, for example, (a-1) a compound having two or more epoxy groups and (a-2). ) A compound or the like obtained by reacting with an unsaturated monocarboxylic acid can be used.

Here, examples of the compound having two or more epoxy groups (a-1) include, for example, a bisphenol type epoxy compound obtained by reacting bisphenol A type or bisphenol F type with epichlorohydrin, hydrogenated bisphenol A type or hydrogenated compound. Examples thereof include hydrogenated bisphenol type epoxy compounds obtained by reacting bisphenol F type with epichlorohydrin, amino group-containing epoxy compounds, alicyclic epoxy compounds, epoxidized polybutadiene, and the like. Further, a novolak type epoxy compound obtained by reacting novolaks with epichlorohydrin can also be preferably used. The above novolaks are obtained, for example, by reacting phenol, cresol, halogenated phenol or alkylphenol with formaldehyde in the presence of an acidic catalyst. Examples of the novolak type epoxy compound include YDCN-701, YDCN-704, YDPN-638 and YDPN-602 manufactured by Nittetsu Chemical & Materials Co., Ltd., DEN-431 and DEN-439 manufactured by Dow Chemical Co., Ltd., and EPN manufactured by Ciba Gaigi Co., Ltd. -1299, N-730, N-770, N-865, N-665, N-673, VH-415 and VH-4240 manufactured by DIC Corporation, EOCN-120 and BREN manufactured by Nippon Kayaku Co., Ltd., etc. It is commercially available.

As the compound having two or more epoxy groups, salicylaldehyde-phenol type epoxy compound, cresol type epoxy compound (EPPN502H, FAE2500, etc. manufactured by Nippon Kayaku Co., Ltd.) and the like are also preferably used. In addition, for example, Mitsubishi Chemical Co., Ltd. Epicoat 828, Epicoat 1007 and Epicoat 807, DIC Corporation Epicron 840, Epicron 860 and Epicron 3050, Dow Chemical Co., Ltd. DER-330, DER-337 and DER-361, Serokiside 2021 manufactured by Daicel Corporation, TETRAD-X and TETRAD-C manufactured by Mitsubishi Gas Chemical Company, Inc., EPB-13 and EPB-27 manufactured by Nippon Soda Co., Ltd. can be used. Further, as the compound having two or more epoxy groups, a mixture of the above-mentioned compounds, a block copolymer, or the like may be used.

Examples of the (a-2) unsaturated monocarboxylic acid include (meth) acrylic acid, crotonic acid, cinnamic acid and the like, of which acrylic acid is preferable from the viewpoint of photosensitivity and solder heat resistance. Further, as the unsaturated monocarboxylic acid, a compound obtained by reacting a saturated or unsaturated polybasic acid anhydride with an unsaturated monoalcohol compound can also be preferably used. These can be used alone or in combination of two or more.

Here, as the saturated or unsaturated polybasic acid anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, succinic anhydride, itaconic anhydride, methylhexa Dibasic acid anhydrides such as hydrohydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, chlorendic anhydride, methyltetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetra Aromatic polyvalent carboxylic acid anhydrides such as carboxylic acid dianhydride, and other accompanying examples such as 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride. Examples thereof include a polyvalent carboxylic acid anhydride derivative such as a product. Examples of the unsaturated monoalcohol compound include (meth) acrylates having one hydroxyl group, saturated or unsaturated dibasic acid semi-ester compounds, and the like. Further, examples of the semi-ester compounds include compounds obtained by reacting a saturated or unsaturated dibasic acid with an unsaturated monoglycidyl compound, and examples of such semi-ester compounds include phthalic acid and tetrahydrophthal. Acids, hexahydrophthalic acid, maleic acid or succinic acid and hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, tris (hydroxyethyl) isocyanurate di (meth) acrylate or glycidyl (meth) acrylate. It can be obtained by reacting at an equimolar ratio by a conventional method.

Examples of the (b) diisocyanate compound include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethylene diisocyanate, o-xylene diisocyanate, m-xylene diisocyanate, and o-xylene diisocyanate. , O-Hluene diisocyanide, m-Hydroxylene diisocyanate, p-Hydroxylene diisocyanate, Methylenebis (cyclohexyl isocyanate), trimethylhexamethylene diisocyanate, cyclohexane-1,3-dimethylene diisocyanate, cyclohexane-1,4-dimethi Examples thereof include reranged isocyanate and 1,5-naphthalenediocyanide. These can be used alone or in combination of two or more.

Examples of the diol compound (c) having a carboxyl group include dimethylolpropionic acid and trimethylolbutanoic acid.

The urethane resin obtained by reacting (a) an epoxy acrylate compound having an ethylenically unsaturated group and two or more hydroxyl groups, (b) a diisocyanate compound, and (c) a diol compound having a carboxyl group is UXE-. 3011, UXE-3012, UXE-3024 (manufactured by Nippon Kayaku Co., Ltd., trade name) can be exemplified. Of these, UXE-3024 (manufactured by Nippon Kayaku Co., Ltd., trade name) is most preferable from the viewpoint of flame retardancy, heat impact resistance, and solder heat resistance.

Further, as a urethane resin obtained by reacting (a) an epoxy acrylate compound having an ethylenically unsaturated group and two or more hydroxyl groups, (b) a diisocyanate compound, and (c) a diol compound having a carboxyl group. For example, a urethane resin having a structure represented by the following general formula (1) is preferable.

In the general formula (1), R ¹¹ is an epoxy acrylate residue, R ¹² is a diisocyanate residue, R ¹³ is an alkyl group having 1 to 5 carbon atoms, and R ¹⁴ is a hydrogen atom or a methyl group. The residue refers to the structure of the portion of the raw material component excluding the functional group provided for bonding. Further, a plurality of groups in the formula may be the same or different from each other.

Further, as the component (a1), a polymer obtained by reacting a diol compound, a diisocyanate compound, a diol compound having a carboxyl group, and a monohydroxy compound having an ethylenically unsaturated group can also be preferably used. Here, examples of the diol compound include 1,6-hexanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, polycarbonate diol, polyester diol, and polycaprolactone diol. , Polybutadienediol and the like, and examples of the monohydroxy compound having an ethylenically unsaturated group include 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate.

The component (a1) preferably has an acid value of 20 to 130 mgKOH / g, more preferably 40 to 110 mgKOH / g, and even more preferably 50 to 100 mgKOH / g. The photosensitive resin composition containing such a component (a1) has better developability with an alkaline aqueous solution, and more excellent resolution can be obtained.

Here, the acid value can be measured as follows. That is, first, about 1 g of a resin solution whose acid value should be measured is precisely weighed, and then 30 g of acetone is added to this resin solution to uniformly dissolve the solution. Next, an appropriate amount of phenolphthalein, which is an indicator, is added to the solution, and titration is performed using a 0.1 N KOH aqueous solution. Then, the acid value is calculated by the following formula.
A = 10 × Vf × 56.1 / (Wp × I)
In the formula, A indicates an acid value (mgKOH / g), Vf indicates a titration amount (mL) of a 0.1 N KOH aqueous solution, Wp indicates the measured weight (g) of the resin solution, and I is measured. The ratio (mass%) of the non-volatile content in the resin solution is shown.

The weight average molecular weight of the component (a1) is 3,000 to 200,000 from the viewpoint of obtaining a coating film property of the photosensitive resin composition and better crack resistance and HAST resistance of the cured film. , More preferably 5,000 to 100,000, and even more preferably 7,000 to 50,000.
The weight average molecular weight (Mw) can be measured by gel permeation chromatography (GPC) (converted to standard polystyrene).

The photosensitive resin composition for laser direct drawing exposure according to the present embodiment preferably contains an acrylic resin as the binder polymer as the component (A). Examples of the acrylic resin include those obtained by polymerizing (radical polymerization or the like) a monomer having an ethylenically unsaturated double bond (polymerizable monomer). Examples of the monomer having such an ethylenically unsaturated double bond include acrylamide such as diacetoneacrylamide, esters of vinyl alcohols such as acrylonitrile and vinyl-n-butyl ether, and (meth) acrylic acid alkyl esters. (Meta) Acrylic Acid Tetrahydrofurfuryl Estel, (Meta) Acrylic Acid Dimethylaminoethyl Estel, (Meta) Acrylic Acid Diethylaminoethyl Estel, (Meta) Acrylic Acid Glycidyl Estel, 2,2,2-Trifluoroethyl (Meta) Acrylic , 2,2,3,3-tetrafluoropropyl (meth) acrylate, (meth) acrylic acid, α-bromo (meth) acrylic acid, α-chloro (meth) acrylic acid, β-frill (meth) acrylic acid, (Meta) acrylic acid-based monomers such as β-styryl (meth) acrylic acid, maleic acid-based monomers such as maleic acid, maleic acid anhydride, monomethyl maleate, monoethyl maleate, monoisopropyl maleate, etc. Examples thereof include acid, silicate acrylic acid, α-cyanoacrylic acid, itaconic acid, crotonic acid, propiole acid and the like. These can be used alone or in combination of two or more.

As the acrylic resin, an acrylic resin (component (a2)) containing (meth) acrylic acid and (meth) acrylic acid alkyl ester as monomer units from the viewpoint of further improving the photosensitivity and the resist shape after photocuring. Is preferable. As the component (a2), a vinyl-based copolymer compound obtained by using methacrylic acid and (meth) acrylic acid alkyl ester as a copolymerization component is more preferable.

Examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, (meth) acrylic acid butyl ester, and (meth) acrylic acid pentyl. Examples thereof include esters, (meth) acrylic acid hexyl esters, (meth) acrylic acid heptyl esters, (meth) acrylic acid octyl esters, and (meth) acrylic acid 2-ethylhexyl esters.

As the component (a2), a component obtained by copolymerizing a (meth) acrylic acid alkyl ester or a (meth) acrylic acid with a vinyl monomer copolymerizable therewith may be used. Examples of such vinyl monomers include (meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid dimethylaminoethyl ester, (meth) acrylic acid diethylaminoethyl ester, and glycidyl methacrylate ester, 2,2,2-. Examples thereof include trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate acrylamide, diacetone acrylamide, styrene and vinyl toluene.

Further, as the component (a2), a copolymer having an ethylenically unsaturated bond introduced into the side chain or the terminal is also suitable. Examples of such copolymers include vinyl polymerizable monomers having a carboxyl group such as acrylic acid, methacrylic acid, fumaric acid, silicic acid, crotonic acid, and itaconic acid, and methyl methacrylate, methyl acrylate, ethyl methacrylate, and ethyl. Acrylate, n-propyl methacrylate, n-propyl acrylate, butyl methacrylate, butyl acrylate, lauryl methacrylate, lauryl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, vinyl toluene, N-vinylpyrrolidone, α-methylstyrene, 2-hydroxy Vinyl polymerizable monomers such as ethyl methacrylate, 2-hydroxyethyl acrylate, acrylamide, acrylonitrile, dimethylaminoethyl methacrylate and dimethylaminoethyl acrylate are mixed with azobisisobutyronitrile, azobisdimethylvaleronitrile, etc. in an organic solvent. Those obtained by general solution polymerization using a polymerization initiator such as benzoyl peroxide can be used.

As the component (A), an acid-modified polyester resin is also preferable. The acid-modified polyester resin has, for example, a chain structure containing an ester bond formed by a polymerization reaction of a diglycidyl ether type epoxy compound catalyzed by a tertiary amine having a pKa of 9.0 or less and a dibasic acid. Examples of the resin contained therein include those having a carboxyl group by adding an acid anhydride to the chain structure.

Examples of the diglycidyl ether type epoxy compound for forming this acid-modified polyester resin include bisphenol A type epoxy resin such as bisphenol A diglycidyl ether, bisphenol F type epoxy resin such as bisphenol F diglycidyl ether, and bisphenol S diglycidyl ether. Bisphenol S type epoxy resin such as biphenol diglycidyl ether, biphenol type epoxy resin such as biphenol diglycidyl ether, bixilenol type epoxy resin such as bixilenol diglycidyl ether, hydrogenated bisphenol A type epoxy resin such as hydrogenated bisphenol A glycidyl ether, these Examples thereof include a dibasic acid-modified diglycidyl ether type epoxy resin. Among these, bisphenol A type epoxy resin is preferable because it has more excellent heat resistance and chemical resistance and does not shrink relatively due to curing. These can be used alone or in combination of two or more.

From the viewpoint of further improving the alkali developability, the acid value of the component (A) is preferably 40 to 170 mgKOH / g, preferably 50 to 150 mgKOH / g, for example, in the case of an acrylic or acid-modified polyester-based binder polymer. It is more preferably g, and even more preferably 60 to 120 mgKOH / g. The weight average molecular weight (Mw) of the binder polymer is preferably 5,000 to 200,000, preferably 10,000, from the viewpoint of further improving the coating film property and the alkali developability of the photosensitive resin composition. It is more preferably ~ 170,000, and more preferably 20,000 to 150,000.

As the component (A), it is preferable to use the above-mentioned component (a1) and component (a2) in combination from the viewpoint of further improving light sensitivity, coating film property and heat resistance.

The content of the component (A) in the photosensitive resin composition for laser direct drawing exposure is preferably 20 to 70% by mass, preferably 20 to 70% by mass, based on the total amount of solid organic compounds in the photosensitive resin composition for laser direct drawing exposure. ~ 60% by mass is more preferable.

Further, when the component (a1) and the component (a2) are contained, the content ratio of the component (a1) is preferably 20 to 100% by mass, more preferably 40 to 100% by mass, based on the total amount of the component (A). The content ratio of the component (a2) is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, based on the total amount of the component (A).

<Ingredient (B)>
The photosensitive resin composition for laser direct drawing exposure according to the present embodiment contains a photopolymerizable compound as the component (B).
Compounds obtained by reacting polyhydric alcohols with α, β-unsaturated carboxylic acids, bisphenol A-based (meth) acrylate compounds, compounds obtained by reacting glycidyl group-containing compounds with α, β-unsaturated carboxylic acids, Examples thereof include urethane monomers such as (meth) acrylate compounds having a urethane bond in the molecule, urethane oligomers and the like. In addition to these, nonylphenoxypolyoxyethylene acrylate, γ-chloro-β-hydroxypropyl-β'-(meth) acryloyloxyethyl-o-phthalate, β-hydroxyalkyl-β'-(meth) acryloyloxy Examples thereof include phthalic acid compounds such as alkyl-o-phthalate, (meth) acrylic acid alkyl ester, and EO-modified nonylphenyl (meth) acrylate. These can be used alone or in combination of two or more.

Here, examples of the compound obtained by reacting a polyhydric alcohol with α, β-unsaturated carboxylic acid include trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, and PO-modified trimethylolpropane. Tri (meth) acrylate, EO or PO-modified trimethylolpropane tri (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa. Examples include (meth) acrylate.

The EO modification indicates that it is modified with ethylene oxide, and the PO modification indicates that it is modified with propylene oxide.

Examples of the bisphenol A-based (meth) acrylate compound include 2,2-bis (4-((meth) acryloxipolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxy). Polypropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxipolybutoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxipolyethoxypolypropoxy) phenyl) propane And so on.

Examples of the above 2,2-bis (4-((meth) acryloxipolyethoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxidiethoxy) phenyl) propane, 2, 2-Bis (4-((meth) acryloxitriethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxitetraethoxy) phenyl) propane, 2,2-bis (4-((() Meta) acryloxipentaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxihexaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptaethoxy) phenyl ) Propane, 2,2-bis (4-((meth) acryloxyoctaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxinonaethoxy) phenyl) propane, 2,2-bis (4-((Meta) acryloxidecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxiune decaethoxy) phenyl) propane, 2,2-bis (4-((meth)) Acryloxidodecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxitridecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxitetradecaethoxy) phenyl) ) Propane, 2,2-bis (4-((meth) acryloxypentadecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexadecaethoxy) phenyl) propane and the like. .. These may be used alone or in combination of two or more. From the viewpoint of reducing the load on the environment, it is preferable to use a halogen-free component (B) described above.

Of the above compounds, 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is commercially available as BPE-500 (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., trade name). 2-Bis (4- (methacryloxypentadecaethoxy) phenyl) is commercially available as BPE-1300 (manufactured by Shin Nakamura Chemical Industry Co., Ltd., trade name).

Examples of the compound obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid include trimethylolpropane triglycidyl ether tri (meth) acrylate and 2,2-bis (4- (meth)). Acryloxy-2-hydroxy-propyloxy) phenyl and the like can be mentioned. Examples of the α, β-unsaturated carboxylic acid for obtaining the above-mentioned compound include (meth) acrylic acid.

Examples of urethane monomers include (meth) acrylic monomers having an OH group at the β-position and diisocyanates such as isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, and 1,6-hexamethylene diisocyanate. Examples thereof include addition reactants with compounds. Further, tris ((meth) acryloxytetraethylene glycol isocyanate) hexamethylene isocyanurate, EO-modified urethane di (meth) acrylate, EO or PO-modified urethane di (meth) acrylate and the like can also be used.

Further, examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, and (meth) acrylic acid 2-ethylhexyl ester. Be done.
One of these components (B) can be used alone or in combination of two or more.

The content of the component (B) is preferably 5 to 45% by mass, preferably 10 to 35% by mass, based on the total amount of the organic compound solid content of the photosensitive resin composition from the viewpoint of tackiness, sensitivity, and resolution. More preferably, it is by mass%. When the content of the component (B) is 5% by mass or more, the sensitivity and resolution tend to be better, and when it is 45% by mass or less, the tackiness tends to be better.

<Ingredient (C)>
The photosensitive resin composition for laser direct drawing exposure according to the present embodiment is particularly limited as long as it can polymerize the photopolymerizable compound of the component (B) as the photopolymerization initiator of the component (C). However, it can be appropriately selected from commonly used photopolymerization initiators.
Examples of the component (C) include benzoins such as benzoin, benzoin methyl ether, and benzoin isopropyl ether; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1. -Dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-methyl-1- [4- (methylthio) phenyl] -2- Acetphenones such as morpholino-1-propanone, N, N-dimethylaminoacetophenone; 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone, etc. Anthraquinones; thioxanthones having a thioxanthone skeleton such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone; Benzophenones such as benzophenone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bis (diethylamino) benzophenone, Michler's ketone, 4-benzoyl-4'-methyldiphenylsulfide; 9-phenylaclydin, 1,7- Acrydins such as bis (9,9'-acrydinyl) heptane; acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphenyl oxide; 1,2-octanedione-1- [4- (phenylthio) phenyl] -2- (O-benzoyloxime), 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl] ethanone 1- (O-acetyloxime), 1-phenyl-1, Oxyme esters such as 2-propanedione-2- [O- (ethoxycarbonyl) oxime]; 2,2'-bis (o-chlorophenyl) -4,5,4', 5'-tetraphenylbiimidazole, 2 , 2'-bis (o-methylphenyl) -4,5,4', 5'-tetraphenylbimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (O, p-dichlorophenyl) biimidazole, 2,2'-bis (o, p-dichlorophenyl) -4,4', 5 , 5'-Tetra (o, p-dichlorophenyl) biimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (p-fluorophenyl) biimidazole, 2,2 '-Bis (o-chlorophenyl) -4,4', 5,5'-Tetra (o, p-dibromophenyl) biimidazole, 2,2'-bis (o-bromophenyl) -4,4', 5 , 5'-tetra (o, p-dichlorophenyl) biimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (p-chloronaphthyl) biimidazole and the like. ..
The hexaphenylbiimidazole compound is preferably one in which the o-position of the benzene ring bonded to the 2,2'-position on the imidazole ring is replaced with a methyl atom, a methoxy group, or a halogen atom, and 4 on the imidazole ring. , 4', 5,5'-position-bonded benzene ring is preferably unsubstituted, or substituted with a halogen atom or a methoxy group. These (C) components may be used alone or in combination of two or more.

The content of the component (C) is 0.2 to 15% by mass, 0.4 to 5% by mass, or 0.6 to 1 based on the total solid content of the photosensitive resin composition for laser direct drawing exposure. It may be appropriately selected from mass%. When the content of the component (C) is 0.2% by mass or more, the exposed portion tends to be difficult to elute during development, and when it is 15.0% by mass or less, the heat resistance is improved.

<(D) Compound having a mercapto group>
(D) The compound having a mercapto group is not particularly limited as long as it is a compound containing a mercapto group. It is considered that the compound (D) having a mercapto group functions effectively as a hydrogen donor and has an effect of further improving the sensitivity and aging stability of the photosensitive resin composition.
Here, the hydrogen donor means a compound capable of donating a hydrogen atom to a radical generated by the exposure treatment of the above-mentioned photopolymerization initiator. In the present invention, the combination of the above-mentioned acylphosphine oxide-based photopolymerizable initiator or hexaphenylbiimidazole compound and the compound having a (D) mercapto group as a hydrogen donor has particularly good linearity of the pattern contour. It is effective in forming a pattern having an excellent resist shape and excellent resolution.

(D) Examples of the compound having a mercapto group include mercaptobenzoxazole (MBO), mercaptobenzothiazole (MBT), mercaptobenzoimidazole (MBI), ethanethiol, benzenethiol, mercaptophenol, mercaptotoluene, and 2-mercaptoethylamine. , Mercaptoethyl alcohol, mercaptoxylene, thioxylenol, 2-mercaptoquinolin, mercaptoacetic acid, α-mercaptopropionic acid, 3-mercaptopropionic acid, mercaptosuccinic acid, thiosalicylic acid, mercaptocyclohexane, α-mercaptodiphenylmethane, C-mercaptotetrazole , Mercaptonaphthalin, mercaptonaphthol, 4-mercaptobiphenyl, mercaptohypoxanthin, mercaptopyridine, 2-mercaptopyrimidine, mercaptopurine, thiokumazone, thiocumothiazone, butane-2,3-dithiol, thiocianulic acid, 2,4,6-trimercapto Examples thereof include −s-triazine, 2-dibutylamino-4,6-dimercapto-s-triazine, 2-anilino-4,6-dimercapto-s-triazine and the like. These (D) compounds having a mercapto group can be used alone or in combination of two or more. Among these, mercaptobenzoxazole (MBO), mercaptobenzothiazole (MBT) and mercaptobenzo are preferable from the viewpoint of effectively functioning as a hydrogen donor and further improving the sensitivity and aging stability of the photosensitive resin composition. An imidazole (MBI), more preferably a mercaptobenzimidazole (MBI) having an imidazole skeleton.

The content of the compound having a mercapto group (D) in the photosensitive resin composition for laser direct drawing exposure is a photosensitive resin composition from the viewpoint of obtaining a photosensitive resin composition capable of forming a pattern having excellent resolution. Based on the total solid content of, preferably 0.01 to 5% by mass, more preferably 0.1 to 3% by mass, still more preferably 0.2 to 1.5% by mass, and particularly preferably 0.6 to 1 by mass. .2% by mass.
(D) When the content of the compound having a mercapto group is 0.01% by mass or more, the solution of the photosensitive resin composition tends to be difficult to gel, and when it is 5% by mass or less, the decrease in sensitivity is suppressed. be able to.

<Ingredient (E)>
The photosensitive resin composition for laser direct drawing exposure of the present invention contains (E) a sensitizer, and a compound having a pyrazoline skeleton is used as the sensitizer. A compound having a pyrazoline skeleton may be referred to as a pyrazoline-based sensitizer.
By adding a pyrazoline-based sensitizer, even with digital exposure, the bottom is not scooped out and the upper part of the resist is not chipped, and the linearity of the pattern contour is good and the resist shape is excellent. A photosensitive resin composition capable of forming a pattern having excellent resolution can be obtained.

The pyrazoline-based sensitizer is not particularly limited as long as it is a sensitizer having a pyrazole ring, but a pyrazoline-based sensitizer represented by the following general formula (2) is preferable.

In the general formula (2), R represents an alkyl group having 4 to 12 carbon atoms, a, b and c each represent an integer of 0 to 2, and the sum of a, b and c is 1 to 6. When the sum of a, b and c is 2 to 6, a plurality of Rs in the same molecule may be the same or different. The alkyl group of R may be linear or branched, or 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. As R, an alkyl group having 4, 8 and 12 carbon atoms is preferable, and more specifically, an n-butyl group, a tert-butyl group, a tert-octyl group, and an n-dodecyl group are preferable. It is preferable that they are the same or different from each other.

Examples of such pyrazoline-based sensitizers include 1- (4-tert-butyl-phenyl) -3-styryl-5-phenyl-pyrazolin and 1-phenyl-3- (4-tert-butyl-styryl) -5. -(4-tert-Butyl-phenyl) -pyrazolin, 1,5-bis- (4-tert-butyl-phenyl) -3- (4-tert-butyl-styryl) -pyrazolin, 1- (4-tert- Octyl-phenyl) -3-styryl-5-phenyl-pyrazolin, 1-phenyl-3- (4-tert-octyl-styryl) -5- (4-tert-octyl-phenyl) -pyrazolin, 1,5-bis -(4-tert-octyl-phenyl) -3- (4-tert-octyl-styryl) -pyrazolin, 1- (4-dodecyl-phenyl) -3-styryl-5-phenyl-pyrazolin, 1-phenyl-3 -(4-Dodecyl-styryl) -5- (4-dodecyl-phenyl) -pyrazolin, 1- (4-dodecyl-phenyl) -3- (4-dodecyl-styryl) -5- (4-dodecyl-phenyl) -Pyrazoline, 1- (4-tert-octyl-phenyl) -3- (4-tert-butyl-styryl) -5- (4-tert-butyl-phenyl) -pyrazolin, 1- (4-tert-butyl- Phenyl) -3- (4-tert-octyl-styryl) -5- (4-tert-octyl-phenyl) -pyrazolin, 1- (4-dodecyl-phenyl) -3- (4-tert-butyl-styryl) -5- (4-tert-Butyl-phenyl) -pyrazolin, 1- (4-tert-butyl-phenyl) -3- (4-dodecyl-styryl) -5- (4-dodecyl-phenyl) -pyrazolin, 1 -(4-Dodecyl-phenyl) -3- (4-tert-octyl-styryl) -5- (4-tert-octyl-phenyl) -pyrazolin, 1- (4-tert-octyl-phenyl) -3- ( 4-Dodecyl-styryl) -5- (4-dodecyl-phenyl) -pyrazolin, 1- (2,4-di-n-butyl-phenyl) -3- (4-dodecyl-styryl) -5- (4-) Dodecyl-phenyl) -pyrazolin, 1-phenyl-3- (3,5-di-tert-butyl-styryl) -5- (3,5-di-tert-butyl-phenyl) -pyrazolin, 1-phenyl-3 -(2,6-di-tert-butyl-styryl) -5- (2,6-di-tert-butyl-phenyl)- Pyrazoline, 1-phenyl-3- (2,5-di-tert-butyl-styryl) -5- (2,5-di-tert-butyl-phenyl) -pyrazolin, 1-phenyl-3- (2,6) -Di-n-butyl-butyl) -5- (2,6-di-n-butyl-phenyl) -pyrazolin, 1- (3,4-di-tert-butyl-phenyl) -3-styryl-5- Phenyl-pyrazolin, 1- (3,5-di-tert-butyl-phenyl) -3-styryl-5-phenyl-pyrazolin, 1- (4-tert-butyl-phenyl) -3- (3,5-di) -Tert-Butyl-steryl) -5- (3,5-di-tert-butyl-phenyl) -pyrazolin and 1- (3,5-di-tert-butyl-phenyl) -3- (3,5-di) -Tert-Butyl-styryl) -5- (3,5-di-tert-butyl-phenyl) -pyrazolin and the like are preferably mentioned.

The content of the pyrazoline-based sensitizer (compound having a pyrazoline skeleton) of the component (E) having a total solid content of 100 parts by mass in the photosensitive resin composition for laser direct drawing exposure is 0.01 to 10.0. By mass is preferable, 0.01 to 5 parts by mass is more preferable, 0.02 to 1 part by mass is further preferable, 0.03 to 0.5 parts by mass is particularly preferable, and 0.03 to 0.2 parts by mass is preferable. Very preferable. When the content of the pyrazoline-based sensitizer is 0.01 parts by mass or more, the exposed part is less likely to elute during development, and when it is 10 parts by mass or less, the decrease in heat resistance can be suppressed.

<Other ingredients>
The photosensitive resin composition according to the present embodiment may include a dye such as malakite green, a photocoloring agent such as leuco crystal violet, a heat coloring inhibitor, a plasticizing agent such as p-toluenesulfoneamide, phthalocyanine blue and the like, if necessary. Phthalocyanine-based or azo-based organic pigments, inorganic pigments such as titanium dioxide, fillers composed of inorganic pigments such as silica, alumina, talc, calcium carbonate or barium sulfate, the above-mentioned fillers, organic pigments or inorganic pigments, etc. Wet dispersants, flame retardants, antifoaming agents, stabilizers, adhesion imparting agents, leveling agents, antioxidants, fragrances, imaging agents and the like can be contained. When these components are contained, the content thereof is preferably about 0.01 to 70% by mass based on the total amount of the organic compound solid content of the photosensitive resin composition for laser direct drawing exposure. In addition, the above-mentioned components may be used alone or in combination of two or more.

Further, the photosensitive resin composition for laser direct drawing exposure according to the present embodiment is, if necessary, methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl. It can be dissolved and dispersed in a solvent such as ether or a mixed solvent thereof, and applied as a solution having a solid content of about 30 to 70% by mass.

The photosensitive resin composition for laser direct drawing exposure according to the present embodiment is applied as a liquid resist on a metal surface such as copper, a copper-based alloy, iron, or an iron-based alloy, dried, and then protected as necessary. It can be used by coating it with a film or in the form of a photosensitive element described later.

(Photosensitive element)
Next, a photosensitive element using the photosensitive resin composition for laser direct drawing exposure according to the present embodiment will be described. FIG. 2 is a schematic cross-sectional view showing a preferred embodiment of the photosensitive element according to the present embodiment. The photosensitive element 100 shown in FIG. 2 is composed of a support 10 and a photosensitive resin composition layer (photosensitive layer) 20 provided on the support 10. The photosensitive resin composition layer 20 is a layer made of the photosensitive resin composition according to the present embodiment. Further, in the photosensitive element 100 according to the present embodiment, the surface of the photosensitive resin composition layer 20 on the opposite side of the support 10 may be covered with the protective film 30.

The photosensitive resin composition layer 20 is prepared by dissolving the photosensitive resin composition for laser direct drawing exposure according to the present embodiment in the above solvent or a mixed solvent to obtain a solution having a solid content of about 30 to 70% by mass, and then such a solution. Is preferably formed by coating on the support 10.

The thickness of the photosensitive resin composition layer 20 varies depending on the application, but the thickness after drying after removing the solvent by heating or hot air blowing is preferably 10 to 100 μm, more preferably 20 to 60 μm. When the thickness of the photosensitive resin composition layer 20 is 10 μm or more, industrial coating tends to be easier, and when it is 100 μm or less, the above-mentioned effect produced by the present invention is further enhanced. At the same time, the flexibility and resolution tend to be better.

Examples of the support 10 included in the photosensitive element 100 include a polymer film having heat resistance and solvent resistance such as polyester such as polyethylene terephthalate, polypropylene, and polyethylene.

The thickness of the support 10 is preferably 5 to 100 μm, more preferably 10 to 30 μm. When the thickness is 5 μm or more, the support tends to be less likely to be torn when the support is peeled off before development, and when the thickness is 100 μm or less, the resolution and flexibility tend to be better. be.

The photosensitive element 100 composed of two layers of the support 10 and the photosensitive resin composition layer 20 or the photosensitive element composed of three layers of the support 10 and the photosensitive resin composition layer 20 and the protective film 30 is, for example, , It may be stored as it is, or it may be wound around a core in a roll shape and stored with a protective film interposed therebetween.

[Method of forming resist pattern]
The resist pattern using the photosensitive element according to the present embodiment is photosensitive by laminating the photosensitive element on the circuit forming substrate and irradiating a predetermined portion of the photosensitive resin composition layer with active light. It can be produced by a production method including an exposure step of forming a photocurable portion on the resin composition layer and a developing step of removing the photosensitive resin composition layer other than the photocurable portion.

When the photosensitive element has a protective film, the resist pattern forming method may further include a removing step of removing the protective film from the photosensitive element before the laminating step. Further, in the laminating step, the photosensitive resin composition layer is laminated so that the surface opposite to the support and the circuit forming substrate are in contact with each other. That is, the photosensitive elements are laminated on the circuit board so that the photosensitive resin composition layer and the support are laminated in this order.

The circuit forming substrate includes an insulating layer and an iron-based alloy (copper, copper-based alloy, nickel, chromium, iron, stainless steel, or other iron-based alloy, preferably copper, copper-based alloy, etc.) formed on the insulating layer. A substrate provided with (made of an iron-based alloy).

Examples of the laminating method in the laminating step include a method of laminating the photosensitive resin composition layer by pressing it against a circuit forming substrate while heating it. At the time of such lamination, it is preferable to laminate under reduced pressure from the viewpoint of adhesion and followability. The surface to be laminated is usually the surface of the conductor layer of the circuit forming substrate, but may be a surface other than the conductor layer.

Here, the heating temperature of the photosensitive resin composition layer is preferably 50 to 130 ° C., the crimping pressure is preferably about 0.1 to 1.0 MPa, and the ambient air pressure is 4,000 Pa or less. Is more preferable, but these conditions are not particularly limited. Further, if the photosensitive resin composition layer is heated to 50 to 130 ° C. as described above, it is not always necessary to preheat the circuit forming substrate in advance, but in order to further improve the stackability, the circuit is formed. Preheat treatment of the substrate can also be performed.

After the lamination is completed in this way, a predetermined portion of the photosensitive resin composition layer is irradiated with active light in the exposure step to form a photocurable portion. Examples of the method for forming the photocurable portion include a method of irradiating an active ray in an image shape through a negative or positive mask pattern called artwork. In the present invention, an LDI method and a DLP (Digital Light Processing) exposure method can be applied. It is suitable for exposure by the direct drawing method that does not use a mask pattern such as.

As the light source of the active light, a known light source, for example, a light source that effectively emits ultraviolet rays such as a carbon arc lamp, a mercury vapor arc lamp, an ultra-high pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, and a semiconductor laser can be used. It is also possible to use a light source such as a photographic flood bulb or a solar lamp that effectively emits visible light.

Next, when a support is present on the photosensitive resin composition layer, after removing the support, the photosensitive resin composition layer other than the photocurable portion is subjected to wet development, dry development, or the like in the development step. Is removed and developed to form a resist pattern.

In the case of wet development, it can be developed by a known method such as spraying, rocking dipping, brushing, scraping, etc. using a developing solution such as an alkaline aqueous solution. The developing solution is preferably safe, stable, and has good operability. For example, a dilute solution of sodium carbonate (1 to 5% by mass aqueous solution) at 20 to 50 ° C. is used.

When the resist pattern obtained by the above-mentioned forming method is used as a solder resist for a printed wiring board, for example, after the development step is completed, a high pressure is used for the purpose of improving the solder heat resistance, chemical resistance, etc. of the solder resist. It is preferable to irradiate ultraviolet rays with a mercury lamp or heat with an oven.

When irradiating with ultraviolet rays, the irradiation amount can be adjusted as needed, and for example, irradiation can be performed with an irradiation amount of about ^{0.2 to 10 J / cm 2.} When heating, it is preferably carried out in the range of about 100 to 170 ° C. for about 15 to 90 minutes. Further, both ultraviolet irradiation and heating may be carried out, and one of them may be carried out and then the other may be carried out.

[Manufacturing method of printed wiring board]
The method for producing a printed wiring board of the present invention is a step of forming a photosensitive layer on a substrate using the photosensitive resin composition for laser direct drawing exposure of the present invention or the dry film of the present invention, and a pattern is formed on the photosensitive layer. It has a step of forming (a step of irradiating the predetermined photosensitive portion with active light to form a photocurable portion) and a step of curing the photosensitive layer to form a permanent mask resist.
Specifically, it can be manufactured as follows.
First, a screen printing method, a spray method, a roll coating method, a curtain, etc. By a method such as a coating method or an electrostatic coating method, a film is preferably applied to a thickness of 10 to 200 μm, more preferably 15 to 150 μm, further preferably 20 to 100 μm, and particularly preferably 23 to 50 μm, and then a coating film is applied. A photosensitive layer is provided on the substrate by drying at 60 to 110 ° C. or by thermally laminating the photosensitive element (dry film) of the present invention from which the cover film has been peeled off on the substrate.
Next, the photosensitive layer is brought into direct contact (or non-contact via a transparent film) with an LDI method or a negative film, and the active light is preferably 10 to 2,000 mJ / cm ² , more preferably 100 to 1. , 500 mJ / cm ^2, more preferably 300~1,000mJ / cm ² was irradiated, then, to form a pattern dissolved away (development) to the unexposed portion with a dilute aqueous alkaline solution. Examples of the active light used include those described above.
Next, the exposed portion of the photosensitive layer is sufficiently cured by post-exposure (ultraviolet exposure) or post-heating to form a permanent mask resist.
The post-exposure condition is preferably the above-mentioned condition.
After that, wiring is formed by etching using the formed resist as a mask, and a printed wiring board is produced. Alternatively, a printed wiring board is further provided with a step of plating an exposed substrate with a resist pattern as a mask to form a plated conductor pattern, and after a step of forming a conductor pattern if necessary, a step of removing a photocured portion. Is produced.

Hereinafter, examples of the present invention will be described.
(Example 1)
[Making varnish]
The raw material containing 57 parts by mass of the photosensitive resin A as the binder polymer of the component (A) and 43 parts by mass of the photopolymerizable compound B as the photopolymerizable compound of the component (B) has a pyrazoline skeleton of the component (E). 0.1 part by mass of pyrazoline-based sensitizer E as a compound, 4.5 parts by mass of HABI (hexaarylbisimidazole) -based photopolymerization initiator C as a photopolymerization initiator of component (C), and 4.5 parts by mass of component (D) As a compound having a mercapto group, 1.0 part by mass of compound D having a mercapto group, 0.04 part by mass of dye F, 0.5 part by mass of adhesion imparting agent G, 20 parts by mass of toluene, 50 parts by mass of methanol, acetone. 15 parts by mass was added and stirred at 20 ° C. for 1 hour to obtain a photosensitive resin composition varnish for laser direct drawing exposure having a non-volatile content of 56% by mass.

The materials used above are shown below.
(A) Binder polymer; Photosensitive resin A; Hitachi Kasei Co., Ltd., Methacrylate / Methyl methacrylate / Ethyl acrylate / Styrene copolymer ・ (B) Photopolymerizable compound B; Hitachi Kasei Co., Ltd., Bisphenol A Polyoxyethylene dimethacrylate and bisphenol A (EO) 30 dimethacrylate mixture (C) photopolymerization initiator; HABI-based photopolymerization initiator C; manufactured by Joshu Strong Electronics New Materials Co., Ltd., 2,2'-biz (o-chlorophenyl) ) -4,4', 5,5'-Tetraphenyl-1,2'-biimidazole- (D) Compound D having a mercapto group; 2-mercaptobenzimidazoline (E) pyrazoline manufactured by Tokyo Kasei Kogyo Co., Ltd. Compound having skeleton; Pyrazoline-based sensitizer E; Nippon Kagaku Kogyo Co., Ltd., Pyrazoline-based ultraviolet absorber (F) Dye F; Tokyo Aniline Dye Manufacturing Co., Ltd., Malakite Green (G) Adhesion imparting agent G ; A mixture of carboxybenzotriazole, 5-amino-1H-tetrazole, and methoxypropanol manufactured by Sanwa Kasei Co., Ltd.

[Making varnish]
Using a PET (polyethylene terephthalate) film as a support, the photosensitive resin composition varnish for laser direct drawing exposure obtained above was coated with a coater at a coating speed of 2.0 m / min, a drying oven 1 zone at 110 ° C. The coating was performed under the condition of two zones at 70 ° C. to obtain a photosensitive element having a thickness of 38 μm after drying.

Then, a printed wiring board (circuit) was manufactured using the obtained photosensitive element.
It was pickled using a copper-clad laminate (copper thickness 35 μm) and preheated in a dryer (80 ° C.).
Lamination was performed on the preheated copper-clad laminate at a surface temperature of 60 to 80 ° C. using a photosensitive element to obtain an evaluation laminate. The laminating conditions are a roll temperature of 90 to 110 ° C., a pressure of 0.3 to 0.5 MPa, and a speed of 1.0 to 2.0 m / min. After laminating, it was allowed to stand for 1 to 2 hours.

(Exposure; Sensitivity)
After the laminating process, a direct drawing exposure machine (manufactured by Hitachi Via Mechanics, Ltd., product name DE-1AH) using a 405 nm blue-violet laser diode as a light source is used to have a grid pattern on the photosensitive resin layer. Using the drawing data, the amount of energy at which the number of remaining step steps after development of the stofer 41-step step tablet is 20 was evaluated. The amount of energy irradiated to each evaluation laminate is shown in Table 1. The smaller the amount of energy, the higher the sensitivity of the photosensitive resin composition.
After exposure, the PET film of the support on the evaluation laminate is peeled off, and the time is 1.7 times the minimum developing time (minimum time for developing the unexposed portion) with a 1% by mass sodium carbonate aqueous solution at 30 ° C. The spray development was performed in. As a result, a pattern formed by curing the photosensitive resin composition layer was formed.

(Adhesion)
The evaluation laminate obtained in the same manner as the above exposure test was subjected to a direct drawing exposure machine (manufactured by Hitachi Via Mechanics, Ltd., product name DE-1AH) using a 405 nm blue-violet laser diode as a light source. Energy that the space width is 400 μm from the top of the above-mentioned evaluation laminate, drawing data having a wiring pattern with a line width of 6 to 47 is used, and the number of remaining step steps after development of the stofer 41-step step tablet is 20. Exposed in quantity.
Peel off the polyethylene terephthalate on the evaluation laminate after exposure, and spray develop with a 1% by mass sodium carbonate aqueous solution at 30 ° C. in 1.7 times the minimum development time (minimum time for removing unexposed areas). Was performed, and the unexposed portion was removed to evaluate the adhesion. The value of adhesion is represented by the smallest value among the line widths (μm) in which the unexposed portion can be completely removed by the developing process, and the smaller this value is, the higher the adhesion is.

(resolution)
The evaluation laminate obtained in the same manner as the above exposure test was subjected to a direct drawing exposure machine (manufactured by Hitachi Via Mechanics, Ltd., product name DE-1AH) using a 405 nm blue-violet laser diode as a light source. Using drawing data having a wiring pattern with a line width / space width of 6/6 to 47/47 (unit: μm) from above the evaluation laminate, the remaining steps after development of the stofer 41-step step tablet. The exposure was performed with an amount of energy such that the number of steps was 20.
Peel off the polyethylene terephthalate on the evaluation laminate after exposure, and spray develop with a 1% by mass sodium carbonate aqueous solution at 30 ° C. in 1.7 times the minimum development time (minimum time for removing unexposed areas). Was performed, and the unexposed portion was removed to evaluate the resolution. The resolution value is represented by the smallest value among the space widths (μm) in which the unexposed portion can be completely removed by the developing process, and the smaller this value is, the higher the resolution is.

(Peeling time)
The peeling time at 50 ° C. was measured using a 3% by mass NaOH solution of the exposed and cured photosensitive layer.

(Formation of conductor pattern by plating)
The photosensitive layer of the evaluation laminate was treated in the same manner as above using a substrate having a space width of about 2 mils (59 μm), and the developed substrate circuit was washed with a degreasing solution manufactured by ROHM & Haas and washed with water. , Soft-etched with ammonium persulfate (APS) and washed with water.
Plating was performed using a copper plating solution manufactured by ROHM & Haas at a current density of 0.5 to 1.5 A / dm ² (ASD) and 60 to 90 min.

After the copper plating, the substrate circuit was washed with a degreasing solution manufactured by ROHM & Haas, washed with water, soft-etched with APS, and washed with water. Then, tin plating with a current density of 0.5 to 1.5 ASD and 5 to 15 minutes was performed using a tin plating solution manufactured by ROHM & Haas (see FIG. 1).

(Example 2)
In Example 1, 1.0 part by mass of compound D having a mercapto group was mixed in exactly the same manner except that it was changed to 0.4 part by mass, and the obtained varnish was used for coating in the same manner as in Example 1. Then, a photosensitive element was prepared and evaluated.

(Comparative Example 1)
In Example 1, 1.0 part by mass of compound D having a mercapto group was blended in exactly the same manner except that it was changed to 0 part by mass, and the obtained varnish was applied in the same manner as in Example 1. A photosensitive element was prepared and evaluated.

(Comparative Example 2)
In Example 1, 57 parts by mass of the binder polymer of the component (A) was blended in exactly the same manner except that it was changed to 0 parts by mass, and the obtained varnish was applied in the same manner as in Example 1 to be photosensitive. Sex elements were prepared and evaluated.
Table 1 shows the measurement of the exposure amount, adhesion, resolution, peeling time, and evaluation results of the evaluation laminates obtained in Examples 1 and 2 and Comparative Examples 1 and 2.

The photosensitive resin composition for laser direct drawing exposure having the components (A) to (E) of the present invention can be exposed even with a small exposure amount, has excellent sensitivity, and is also excellent in resolution and adhesion.
According to the resist pattern and the method for manufacturing a wiring board of the present invention, a photosensitive element (dry film) having high sensitivity and excellent plating resistance, which is suitable for use in circuit formation of a printed wiring board, can be obtained. Further, the photosensitive element of the present invention is suitable for circuit formation and has high sensitivity and excellent plating resistance.

1 ... Resist 2 ... Copper 3 ... Tin 10 ... Support 20 ... Photosensitive resin composition layer 30 ... Protective film 100 ... Photosensitive element

Claims (6)

It contains (A) a binder polymer, (B) a photopolymerizable compound, (C) a photopolymerization initiator, (D) a compound having a mercapto group, and (E) a sensitizer, as a sensitizer for the component (E). A photosensitive resin composition for direct laser drawing exposure, which contains a compound having a pyrazoline skeleton. The photosensitive resin composition for laser direct drawing exposure according to claim 1, wherein the compound having a mercapto group of the component (D) is a compound having a secondary thiol or a tertiary thiol having an imidazole skeleton. A photosensitive element comprising a support and a photosensitive layer on the support using the photosensitive resin composition for laser direct drawing exposure according to claim 1 or 2. (I) A photosensitive layer is formed on a circuit-forming substrate by using the photosensitive resin composition for laser direct drawing exposure according to claim 1 or 2, or the photosensitive element according to claim 3. And the process to do
(Ii) A step of irradiating a predetermined portion of the photosensitive layer with active light to form a photocurable portion,
(Iii) A method for forming a resist pattern, comprising a step of removing at least a part other than the photocurable portion from the photosensitive layer of the circuit forming substrate. A method for manufacturing a printed wiring board, comprising a step of etching or plating a substrate on which a resist pattern is formed by the method for forming a resist pattern according to claim 4 to form a conductor pattern. The method for manufacturing a printed wiring board according to claim 5, further comprising a step of removing the photocurable portion after the step of forming the conductor pattern.

Images