JP2006330193A - Photosensitive resin composition, photosensitive element and method for producing printed wiring board using therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition capable of forming a cured material layer which hardly contaminates a plating solution and exhibits excellent plating resistance even when electroless plating is carried out at a high temperature. <P>SOLUTION: The photosensitive resin composition contains a binder polymer, a photopolymerizable compound having an ethylenically unsaturated bond, a photopolymerization initiator and a guanamine compound represented by formula (1) wherein R<SP>1</SP>denotes H, an alkyl group or an aryl group which may have a substituent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  Conventionally, in a printed wiring board, metal plating is performed on a circuit pattern for the purpose of protecting the circuit pattern. In recent years, the use of Chip Scale Package (CSP) and Ball Grid Array (BGA), which are advantageous for miniaturization, is increasing as mounting parts mounted on printed wiring boards. These mounting components are usually connected to the circuit board by engaging with mounting pads (solder pads) provided on the circuit pattern via solder balls. In this case, a solder resist is generally formed on the entire circuit pattern surface of the circuit board except for the mounting pads. In such a mounting method, metal plating is often performed on the mounting pad described above for the purpose of reducing the contact resistance with the mounting component. As metal plating formed on these circuit patterns and mounting pads, gold plating is frequently used in order to enable good connection of mounted components and the like.

  Further, in recent years, the method of metal plating is rapidly shifting from the conventional electrolytic plating method to the electroless plating method. This is because printed wiring boards are being further miniaturized and densified compared to conventional methods, and conventional electroplating that requires electrode lead attachment cannot cope with such downsizing trends. It is. In addition, electroless plating has an advantage that a plating film having a uniform film thickness and a smooth surface can be obtained. For this reason, the shift to electroless plating is particularly remarkable in the substrate for portable electronic devices.

  However, such portable electronic devices are more susceptible to impacts such as dropping and forces such as bending than conventional electronic devices. When these forces are applied to the portable electronic device, there is a tendency that inconveniences such as mounting components fall off on the board mounted on the portable electronic device.

Therefore, in order to reduce such inconvenience, electroless plating is performed on the solder resist with a layer made of a cured product of the photosensitive resin composition so as to remove the mounting pad, and then this curing is performed. Attempts have been made to form an electroless plating layer better by removing the object layer (see Patent Documents 1 and 2). As a result, the connection reliability between the mounting pad and the solder ball can be improved, and the dropout of the mounted component can be reduced.
JP 2004-12812 A JP 2003-35953 A

  However, the present inventors have examined the above prior art and found that the method for forming a cured layer of the photosensitive resin composition on the solder resist as described above has the following improvements. I found it. That is, the electroless plating is usually performed at a relatively high temperature, but when the electroless plating is performed under such a high temperature condition, the cured product layer tends to be peeled off or torn. That is, the cured product layer made of the photosensitive resin composition had low plating resistance under high temperature conditions. When the cured product layer is peeled or torn like this, it is difficult to sufficiently obtain the advantage of forming the cured product layer as described above, and as a result, mounting components are likely to drop off as in the past. It becomes.

  In order to eliminate such inconvenience, it was effective to add an additive capable of improving adhesion to the photosensitive resin composition, but a photosensitive resin composition containing such an additive is used. In addition, the additive applied during electroless gold plating tends to precipitate in the plating solution. As a result, it has been found that plating is inhibited and a sufficient plating layer cannot be formed.

  Therefore, the present invention has been made in view of such circumstances, and even when electroless plating is performed under high temperature conditions, the plating solution is less contaminated and can exhibit excellent plating resistance. It aims at providing the photosensitive resin composition which can form a hardened | cured material layer. Another object of the present invention is to provide a photosensitive element using such a photosensitive resin composition and a method for producing a printed wiring board using these photosensitive elements.

［式中、Ｒ^１は、水素原子、アルキル基又は置換基を有していてもよいアリール基を示す。］ In order to achieve the above object, the photosensitive resin composition of the present invention is represented by a binder polymer, a photopolymerizable compound having an ethylenically unsaturated bond, a photopolymerization initiator, and the following general formula (1). And a guanamine compound.

[Wherein, R ¹ represents a hydrogen atom, an alkyl group, or an aryl group which may have a substituent. ]

  According to the photosensitive resin composition having such a configuration, in addition to excellent adhesion to a protective layer such as a solder resist provided on a circuit pattern, a cured product layer having excellent strength can be formed. Therefore, according to this photosensitive resin composition, it is possible to form a cured product layer that is less likely to peel or break from the substrate under high-temperature conditions without adding an additive or the like, and has excellent plating resistance. become. As a result, by forming a cured product layer made of this photosensitive resin composition, it is possible to satisfactorily perform electroless plating on a mounting pad or the like without contaminating the plating solution. As a result, the obtained printed wiring board is extremely unlikely to drop off mounted components or the like.

  More specifically, the binder polymer preferably contains an acrylic resin containing (meth) acrylic acid and (meth) acrylic acid alkyl ester as monomer units. Thereby, the adhesiveness of the hardened | cured material layer obtained and the characteristic of intensity | strength become further excellent.

  The photosensitive resin composition of the present invention preferably contains a 2,4,5-triarylimidazole dimer as a photopolymerization initiator. The combination of the above-described guanamine compound that is an additive and the 2,4,5-triarylimidazole dimer that is a photopolymerization initiator further improves the plating resistance of the resulting cured layer.

［式中、Ｒ^２１及びＲ^２２は、それぞれ独立に、炭素数２〜６のアルキレン基、Ｒ^２３及びＲ^２４は、それぞれ独立に、水素原子又はメチル基を示し、ｐ及びｑは、ｐ＋ｑ＝４〜４０を満たす正の整数である。］ Further, the photopolymerizable compound preferably includes a bisphenol A-based (meth) acrylate compound represented by the following general formula (2). The photosensitive resin composition containing such a compound is further excellent in the above-described characteristics.

[Wherein, R ²¹ and R ²² each independently represent an alkylene group having 2 to 6 carbon atoms, R ²³ and R ²⁴ each independently represent a hydrogen atom or a methyl group, and p and q are p + q = It is a positive integer satisfying 4 to 40. ]

  More specifically, in order to obtain the above characteristics satisfactorily, it is preferable that each component of the photosensitive resin composition satisfies the following compounding ratio. That is, with respect to 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound, the content of the binder polymer is 40 to 80 parts by mass, the content of the photopolymerizable compound is 20 to 60 parts by mass, and photopolymerization is started. It is preferable that the content of the agent is 0.1 to 20 parts by mass and the content of the guanamine compound is 0.05 to 10 parts by mass.

  Moreover, this invention provides the photosensitive element using the photosensitive resin composition of the said invention. That is, the photosensitive element of the present invention comprises a support and a photosensitive layer made of the above-described photosensitive resin composition of the present invention provided on the support. According to such a photosensitive element, in the above-described electroless plating method, it is possible to more easily form a cured product layer on a protective layer such as a solder resist.

  Here, it is more preferable that the photosensitive layer in this photosensitive element has a transmittance of 5 to 75% for light having a wavelength of 365 nm. Such a photosensitive layer can sufficiently diffuse actinic rays in the wavelength region used for curing in the layer, and therefore can be sufficiently cured easily. As a result, it has high adhesiveness and strength, whereby a cured product layer having excellent plating resistance can be formed.

  The present invention further provides a method for producing a printed wiring board using the photosensitive resin composition or photosensitive element of the present invention. That is, the first printed wiring board manufacturing method of the present invention includes a circuit board provided with a circuit pattern, and a protective layer that covers the surface of the circuit board so that an exposed portion from which a part of the circuit pattern is exposed is formed. A photosensitive layer forming step of forming a photosensitive layer comprising the photosensitive resin composition of the present invention on a protective layer of a circuit board with a protective layer provided, and irradiating actinic rays to a region other than the region on the exposed portion of the photosensitive layer An exposure step for forming an exposed portion, a developing step for removing regions other than the exposed portion in the photosensitive layer to expose the exposed portion, a plating step for performing electroless plating on the exposed portion, and removing the exposed portion And a removing step.

  Further, the second printed wiring board manufacturing method of the present invention includes a circuit board provided with a circuit pattern, a protective layer covering the surface of the circuit board so that an exposed portion from which a part of the circuit pattern is exposed, A photosensitive layer forming step of laminating a photosensitive layer in the photosensitive element of the present invention on a protective layer of a circuit board with a protective layer, and irradiating actinic rays to a region other than the region on the exposed portion of the photosensitive layer An exposure step for forming an exposed portion, a developing step for removing regions other than the exposed portion in the photosensitive layer to expose the exposed portion, a plating step for performing electroless plating on the exposed portion, and a removal for removing the exposed portion And a process.

  In these printed wiring board manufacturing methods, since a cured product layer obtained from the photosensitive resin composition of the present invention is formed on a protective layer formed on a circuit board, a mounting pad ( The electroless plating can be satisfactorily performed on the exposed portion). As a result, when the obtained printed wiring board is joined to a mounted component or the like, the mounted component is hardly dropped off.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where electroless plating is performed on high temperature conditions, the photosensitive resin composition which can form the hardened | cured material layer which can exhibit the outstanding metal-plating resistance can be provided. . Moreover, according to this invention, the manufacturing method of the photosensitive element using such a photosensitive resin composition and a printed wiring board using these can be provided.

Hereinafter, preferred embodiments of the present invention will be described in detail.
[Photosensitive element]

  FIG. 1 is a diagram schematically showing a cross-sectional configuration of a photosensitive element according to a preferred embodiment. The photosensitive element 1 includes a support 10, a photosensitive layer 20 provided on the support 10, and a protective film 30 provided on the photosensitive layer 20.

  First, the photosensitive layer 20 will be described. The photosensitive layer 20 is a layer composed of a photosensitive resin composition. The photosensitive resin composition constituting the photosensitive layer includes (A) a binder polymer (hereinafter referred to as “A component”), (B) a photopolymerizable compound having an ethylenically unsaturated bond (hereinafter referred to as “B component”). , (C) a photopolymerization initiator (hereinafter referred to as “C component”) and (D) an additive containing a guanamine compound represented by the general formula (1) (hereinafter referred to as “D component”). Yes. Hereinafter, the A component, the B component, the C component, and the D component will be described in detail.

(A component)
First, the A component will be described. Examples of the component A include acrylic resins, styrene resins, epoxy resins, amide resins, amide epoxy resins, alkyd resins, and phenol resins. From the viewpoint of excellent alkali developability, it is preferable to use an acrylic resin. These can be used individually by 1 type or in combination of 2 or more types.

  Such component A can be produced, for example, by radical polymerization of a polymerizable monomer. Examples of the polymerizable monomer include polymerizable styrene derivatives substituted at the α-position or aromatic ring such as styrene, vinyl toluene, α-methylstyrene, acrylamide such as diacetone acrylamide, acrylonitrile, vinyl, and the like. -Esters of vinyl alcohol such as n-butyl ether, (meth) acrylic acid alkyl ester, (meth) acrylic acid tetrahydrofurfuryl ester, (meth) acrylic acid dimethylaminoethyl ester, (meth) acrylic acid diethylaminoethyl ester, ( (Meth) acrylic acid glycidyl ester, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, (meth) acrylic acid, α-bromo (meth) acryl Acid, α-chloro ( T) Acrylic acid, β-furyl (meth) acrylic acid, β-styryl (meth) acrylic acid, maleic acid, maleic anhydride, monomethyl maleate, monoethyl maleate, monoisopropyl maleate and the like, Examples include fumaric acid, cinnamic acid, α-cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid. As the component A, two or more of these may be used in combination.

  Here, in the present specification, (meth) acrylic acid means acrylic acid and methacrylic acid corresponding thereto, (meth) acrylate means acrylate and methacrylate corresponding thereto, and (meth) acryloyl. The group means an acryloyl group and a corresponding methacryloyl group.

［式中、Ｒ^３１は、水素原子又はメチル基、Ｒ^３２は、炭素数１〜１２のアルキル基を示す。］ Examples of the (meth) acrylic acid alkyl ester include compounds represented by the following general formula (3) and those obtained by substituting a hydroxyl group, an epoxy group, a halogen or the like on the alkyl group of this compound.

[Wherein R ³¹ represents a hydrogen atom or a methyl group, and R ³² represents an alkyl group having 1 to 12 carbon atoms. ]

Examples of the group represented by R ³² in the above formula (3) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, and an undecyl group. , Dodecyl groups and structural isomers thereof.

  More specifically, examples of the compound represented by the formula (3) include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, and (meth) acrylic acid butyl. Ester, (meth) acrylic acid pentyl ester, (meth) acrylic acid hexyl ester, (meth) acrylic acid heptyl ester, (meth) acrylic acid octyl ester, (meth) acrylic acid-2-ethylhexyl ester, (meth) acrylic acid Nonyl ester, (meth) acrylic acid decyl ester, (meth) acrylic acid undecyl ester, (meth) acrylic acid dodecyl ester may be mentioned. These can be used individually by 1 type or in combination of 2 or more types.

  As the component A, those containing a carboxyl group are preferable from the viewpoint of improving alkali developability as described later. Examples of such component A include those obtained by radical polymerization of a polymerizable monomer having a carboxyl group and other polymerizable monomers. Such A component may have a photosensitive group as appropriate. As the polymerizable monomer having a carboxyl group, (meth) acrylic acid as described above is preferable.

  Among these, as the component A, an acrylic resin containing (meth) acrylic acid and / or (meth) acrylic acid alkyl ester as a monomer unit from the viewpoint of improving the alkali developability and the releasability of the resist after light irradiation. It is preferable to contain, and it is more preferable to contain acrylic resin containing (meth) acrylic acid and (meth) acrylic acid alkyl ester as monomer units. Moreover, what further contains styrene or a styrene derivative as a monomer unit as another polymerizable monomer is preferable. By including styrene or a styrene derivative as a monomer unit, the adhesion and peelability of the resulting cured product layer are further improved. In particular, as the component A, (meth) acrylic acid, (meth) acrylic acid alkyl ester, and a copolymer obtained using styrene or a styrene derivative as a copolymerization component are preferable.

  By using styrene or a styrene derivative as a copolymerization component, both the adhesiveness and the release characteristics of the photosensitive resin composition are improved. The content of this styrene or styrene derivative is preferably 2 to 40% by mass, more preferably 3 to 28% by mass, based on the total amount of copolymerization components for forming the component A, and 5 to 27 More preferably, it is mass%. When the content is less than 2% by mass, the adhesiveness of the photosensitive resin composition tends to decrease. On the other hand, if it exceeds 40% by mass, the peeling piece tends to be large and the peeling time tends to be long.

  The acid value of such an A component is preferably 30 to 250 mgKOH / g, and more preferably 50 to 200 mgKOH / g. If the acid value is less than 30 mg KOH / g, the development time tends to be longer. On the other hand, when it exceeds 250 mgKOH / g, the developing solution resistance of the photocured resist tends to be lowered. In addition, when developing with a solvent at the time of image development, it is desirable to adjust the compounding quantity of the polymerizable monomer which has a carboxyl group so that it may become small compared with the case where solvent development is not performed.

  Furthermore, the weight average molecular weight of the component A is preferably 20,000 to 300,000, and more preferably 40,000 to 150,000. When the weight average molecular weight is less than 20,000, the developer resistance of the photosensitive resin composition tends to be lowered. On the other hand, if it exceeds 300,000, the development time tends to be longer.

  As the component A, the above-described compounds and the like can be applied alone or in combination of two or more. Suitable combinations of two or more A components include, for example, combinations obtained from different copolymer components, those having different weight average molecular weights, and those having different degrees of dispersion. .

(B component)
Next, the B component will be described. As the component B, for example, a compound obtained by reacting an α, β-unsaturated carboxylic acid with a polyhydric alcohol, a bisphenol A (meth) acrylate compound, an α, β-unsaturated carboxylic acid to a glycidyl group-containing compound. Examples include compounds obtained by reaction, urethane monomers or urethane oligomers such as (meth) acrylate compounds having a urethane bond in the molecule. Besides these, nonylphenoxy polyoxyethylene acrylate, phthalic acid compounds (for example, γ-chloro-β-hydroxypropyl-β ′-(meth) acryloyloxyethyl-o-phthalate, β-hydroxyalkyl-β '-(Meth) acryloyloxyalkyl-o-phthalate, etc.), (meth) acrylic acid alkyl ester, EO-modified nonylphenyl (meth) acrylate, and the like can be exemplified.

  Among these, a bisphenol A-based (meth) acrylate compound or a (meth) acrylate compound having a urethane bond in the molecule is preferable because it can improve the plating resistance and adhesion of the resulting resist pattern, and the above formula (2) A bisphenol A (meth) acrylate compound represented by the formula is particularly preferred. In addition, although a B component is a compound which has an ethylenically unsaturated bond in a molecule | numerator as above-mentioned, as this B component, the compound mentioned above can be used individually or in combination of 2 or more types. As a combination of two or more kinds, a combination of a compound having one ethylenically unsaturated bond in the molecule and a compound having two or more ethylenically unsaturated bonds in the molecule can improve sensitivity and resolution. Particularly preferred.

  Among the compounds described above, examples of the compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid include, for example, polyethylene glycol di (meth) acrylate having 2 to 14 ethylene groups, propylene group Polypropylene glycol di (meth) acrylate having 2-14 in number, polyethylene polypropylene glycol di (meth) acrylate having 2-14 in number of ethylene groups and 2-14 in number of propylene groups, trimethylolpropane di (Meth) acrylate, trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO, PO-modified trimethylolpropane tri (meth) acrylate, tetramethylo Examples include rumethane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate.

  Here, EO and PO represent ethylene oxide and propylene oxide, respectively, the EO-modified compound has a block structure of ethylene oxide group, and the PO-modified compound has a block structure of propylene oxide group. It is what you have. These can be used alone or in combination of two or more.

  Examples of the bisphenol A-based (meth) acrylate compound include 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxy). Polypropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolybutoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane Etc. These can be used alone or in combination of two or more.

  More specifically, as 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane, for example, 2,2-bis (4-((meth) acryloxydiethoxy) phenyl) Propane, 2,2-bis (4-((meth) acryloxytriethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetraethoxy) phenyl) propane, 2,2-bis ( 4-((meth) acryloxypentaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxy) Heptaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyoctaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryl) Xinonaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxydecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyundecaethoxy) phenyl) propane, 2 , 2-bis (4-((meth) acryloxydodecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytridecaethoxy) phenyl) propane, 2,2-bis (4- ((Meth) acryloxytetradecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxy) Hexadecaethoxy) phenyl) propane and the like. These can be used alone or in combination of two or more.

  Of these, 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is commercially available as BPE-500 (product name, manufactured by Shin-Nakamura Chemical Co., Ltd.). -Bis (4- (methacryloxypentadecaethoxy) phenyl) propane is commercially available as BPE-1300 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.). These can be used alone or in combination of two or more. The number of ethylene oxide groups in one molecule of 2,2-bis (4- (methacryloxypolyethoxy) phenyl) propane is preferably 4-20, and more preferably 8-15.

(C component)
Next, the C component will be described. Examples of the component C include benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N′-tetraethyl-4,4′-diaminobenzophenone, 4-methoxy-4′-. Such as dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone-1, etc. Aromatic ketone; 2-ethylanthraquinone, phenanthrenequinone, 2-t-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1 -Chloroanthraquinone, 2-methylant Quinones such as quinone, 1,4-naphthoquinone, 9,10-phenantharaquinone, 2-methyl 1,4-naphthoquinone and 2,3-dimethylanthraquinone; benzoins such as benzoin methyl ether, benzoin ethyl ether and benzoin phenyl ether Ether compounds; benzoin compounds such as benzoin, methylbenzoin, and ethylbenzoin; benzyl derivatives such as benzyldimethyl ketal; 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4 , 5-Di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer , 2- (p-methoxyphenyl)- 2,4,5-triarylimidazole dimers such as 4,5-diphenylimidazole dimer; acridine derivatives such as 9-phenylacridine, 1,7-bis (9,9'-acridinyl) heptane, N- N-phenylglycine derivatives such as phenylglycine; coumarin compounds; reaction products of thioxanthone compounds such as diethylthioxanthone and tertiary amine compounds such as dimethylaminobenzoic acid. These may be used alone or in combination of two or more.

(D component)
The photosensitive resin composition of this embodiment contains the guanamine compound represented by the said General formula (1) at least as D component. In the compound represented by the general formula (1), the group represented by R ¹ is preferably a methyl group or a phenyl group. Among these, benzoguanamine or acetoguanamine is suitable as such a guanamine compound.

  As mentioned above, although the AD component contained in the photosensitive resin composition of suitable embodiment was demonstrated, when these AD components are contained with the content shown below in the photosensitive resin composition. preferable.

  First, the content of the A component is preferably 40 to 80 parts by mass and more preferably 45 to 70 parts by mass with respect to 100 parts by mass of the total amount of the A component and the B component. When the content of the component A is less than 40 parts by mass, the cured product layer made of the cured product of the photosensitive resin composition becomes brittle and the coating properties at the time of forming the photosensitive element tend to deteriorate. On the other hand, when it exceeds 80 mass parts, it exists in the tendency for a sensitivity to fall. In the present specification, “part by mass” is substantially equivalent to a weight reference value (“part by weight”).

  Moreover, content of B component is preferable in it being 20-60 mass parts with respect to 100 mass parts of total amounts of A component and B component, and it is more preferable in it being 30-55 mass parts. When this content is less than 20 parts by mass, the sensitivity of the photosensitive resin composition tends to be insufficient, and when it exceeds 60 parts by mass, the cured product layer tends to become brittle.

  Furthermore, the content of the C component is preferably 0.1 to 20 parts by mass and more preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the total amount of the A component and the B component. When the content is less than 0.1 parts by mass, the sensitivity of the photosensitive resin composition tends to be insufficient. When the content exceeds 20 parts by mass, the activity in the surface region of the photosensitive layer 20 is exposed during exposure. Light absorption may increase, and the lower layer may not be sufficiently cured.

  Furthermore, the content of the D component is preferably 0.05 to 10 parts by mass and more preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the total amount of the A component and the B component. When the content of the D component is less than 0.05 parts by mass, the adhesion to the lower protective layer and the circuit board tends to be insufficient during the production of the printed wiring board. On the other hand, if it exceeds 10 parts by mass, plating bath contamination may occur during plating.

  In addition, the photosensitive resin composition of this embodiment may further contain other components according to the desired property in addition to the above-described components A to D. Examples of other components include dyes such as malachite green, photochromic agents such as tribromophenyl sulfone and leuco crystal violet, thermochromic inhibitors, plasticizers such as p-toluenesulfonamide, pigments, fillers, antifoaming agents, Examples include flame retardants, stabilizers, adhesion imparting agents, leveling agents, peeling accelerators, antioxidants, fragrances, imaging agents, and thermal crosslinking agents. The content of these components is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the total amount of component A and component B, respectively. These can be used individually by 1 type or in combination of 2 or more types.

  Moreover, the photosensitive resin composition may be in the form of a varnish containing a solvent as necessary. Examples of the solvent include methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether, and mixed solvents thereof. The varnish is preferably a solution having a solid content of about 30 to 60% by mass because application described later becomes easy.

  In the photosensitive element 1 having the above-described configuration, the thickness of the photosensitive layer 20 is preferably 1 to 100 μm, and more preferably 1 to 50 μm. It tends to be difficult to form the photosensitive layer 20 having a thickness of less than 1 μm. On the other hand, when the thickness of the photosensitive layer 20 exceeds 100 μm, the adhesiveness to the protective layer and the circuit board on which the photosensitive layer 20 is laminated decreases, and the resolution of the layer 20 tends to decrease.

  Further, the photosensitive layer 20 has a transmittance for light having a wavelength of 365 nm of preferably 5 to 75%, more preferably 7 to 60%, and still more preferably 10 to 40%. When the transmittance is less than 5%, the adhesion of the photosensitive layer tends to be insufficient. On the other hand, if it exceeds 75%, the actinic ray may not be sufficiently absorbed and the resolution may be lowered. Such transmittance can be measured by a UV spectrometer. Examples of the UV spectrometer include a 228A type W beam spectrophotometer manufactured by Hitachi, Ltd.

  Examples of the support 10 in the photosensitive element 1 include a polymer film having heat resistance and solvent resistance such as polyethylene terephthalate, polypropylene, polyethylene, and polyester. The thickness of the support 10 is preferably 5 to 25 μm, more preferably 8 to 20 μm, and still more preferably 10 to 16 μm. If the thickness is less than 5 μm, tearing tends to occur when peeling from the photosensitive layer 20. On the other hand, when the thickness exceeds 25 μm, the resolution of the photosensitive layer 20 tends to decrease when exposure is performed through the support 10.

  The haze of the support 10 is preferably 0.001 to 5.0, more preferably 0.001 to 2.0, and still more preferably 0.01 to 1.8. When the haze of the support 10 exceeds 2.0, the resolution of the photosensitive layer 20 tends to decrease when exposure is performed through the support 10. Such haze can be measured by a method based on JIS K 7105, and can be measured by, for example, a turbidimeter (NHD-1001DP (manufactured by Nippon Denshoku Industries Co., Ltd.)).

  Examples of the protective film 30 include polymer films having heat resistance and solvent resistance such as polyethylene terephthalate, polypropylene, polyethylene, and polyester. As the protective film 30, it is preferable to select and use a film having an adhesive force with respect to the photosensitive layer 20 smaller than that of the support 10, and more preferably a low fish eye film.

  The thickness of the protective film 30 is preferably 5 to 30 μm, more preferably 10 to 28 μm, and still more preferably 15 to 25 μm. If the thickness is less than 5 μm, tearing may occur when peeling from the photosensitive layer 20. On the other hand, a protective film exceeding 30 μm tends to cause an unnecessary increase in cost.

  The tensile strength in the longitudinal direction of the protective film 30 is preferably 13 MPa or more, more preferably 13 to 100 MPa, still more preferably 15 to 100 MPa, and particularly preferably 16 to 100 MPa. If the tensile strength is less than 13 MPa, there is a risk of tearing when peeling from the photosensitive layer 20. Further, the tensile strength in the short direction is preferably 9 MPa or more, more preferably 9 to 100 MPa, further preferably 10 to 100 MPa, particularly preferably 11 to 100 MPa, and 12 to 100 MPa. It is extremely preferable. If the tensile strength is less than 9 MPa, tearing may occur at the time of peeling from the photosensitive layer 20. These tensile strengths can be measured according to JIS C 2318-1997 (5.3.3). For example, it can be measured by a tensile strength tester such as Tensilon manufactured by Toyo Baldwin.

  In addition, the support body 10 and the protective film 30 in the photosensitive element 1 may perform an appropriate surface treatment as necessary. However, since these are finally peeled off from the photosensitive layer 20, it is desirable to perform a surface treatment that does not inhibit such peeling. Furthermore, the support 10 or the protective film 30 may be subjected to an antistatic treatment.

  The photosensitive element 1 which has the said structure can be manufactured by the method shown below, for example. For example, after applying a coating solution obtained by dissolving the above-described photosensitive resin composition in a predetermined solvent on the support 10, the solvent is removed to form the photosensitive layer 20, and then the photosensitive layer 20. The method of laminating | stacking protective films, such as an above-described polypropylene film, is mentioned. As this coating liquid, the varnish of the photosensitive resin composition as described above is suitable.

  Examples of the coating method include a roll coater, a comma coater, a gravure coater, an air knife coater, a die coater, and a bar coater. The solvent can be removed, for example, by heating. In this case, the heating temperature is preferably about 70 to 150 ° C., and the heating time is preferably about 5 to 30 minutes. The solvent remaining amount in the photosensitive layer 20 after removal of the solvent is desirably 2% by mass or less from the viewpoint of preventing the diffusion of the solvent in the subsequent steps. Moreover, as a method of laminating a polypropylene film on the photosensitive layer 20, for example, a method of pressing with a roll while supplying the polypropylene film onto the photosensitive layer can be mentioned.

The photosensitive element 1 thus obtained can be stored, for example, in the form of a flat plate as it is, or wound around a cylindrical core or the like and rolled. Note that the photosensitive element 1 does not necessarily have the protective film 30 described above, and may have a two-layer structure of the support 10 and the photosensitive layer 20.
[Method of manufacturing printed wiring board]

  Next, a method for manufacturing a printed wiring board using the photosensitive element 1 described above will be described with reference to FIG. Drawing 2 is a figure showing typically the manufacturing process of the printed wiring board concerning an embodiment.

  In the method for manufacturing a printed wiring board according to the present embodiment, first, a circuit board with a protective layer including a circuit board 80 having a circuit pattern 50 on the board 40 and a protective layer 60 covering the circuit pattern surface of the circuit board 80. 90 is prepared (FIG. 2A). In the circuit board 90 with a protective layer, an opening 70 is formed in a part of the protective layer 60. A part of the circuit pattern 50 is exposed through the opening 70 to form an exposed portion 50a. As the substrate 40, the circuit pattern 50, and the protective layer 60, a substrate, a wiring material, and a solder resist used in a conventional printed wiring board can be applied. Such a circuit substrate 90 with a protective layer is a known circuit board. It can be manufactured by a manufacturing method.

  Next, the photosensitive element 1 of the above-described embodiment is adhered on the protective layer 60 in the circuit board 90 with the protective layer so that the photosensitive layer 20 is in contact with the protective layer 60, and the photosensitive layer 20 is formed on the protective layer 60. Are laminated (FIG. 2B; photosensitive layer forming step).

  Examples of the method for laminating the photosensitive layer 20 include a method in which when the protective film 30 is present on the photosensitive element 1, after removing the protective film 30, the photosensitive layer 20 is pressure-bonded to the circuit board 90 with the protective layer while heating. . In addition, it is preferable to perform this pressure bonding under reduced pressure from a viewpoint of improving adhesiveness and followable | trackability.

At this time, the heating temperature of the photosensitive layer 20 is preferably 70 to 130 ° C., and the pressure bonding pressure is preferably about 0.1 to 1.0 MPa (about 1 to 10 kgf / cm ² ). However, these conditions are not particularly limited. In addition, in order to further improve the lamination property, the pre-heat treatment of the circuit board 90 with the protective layer may be performed. However, when the photosensitive layer 20 is heated to 70 to 130 ° C. as described above, this pre-heat treatment is not necessarily required.

  Next, the photosensitive layer 20 is irradiated with an actinic ray L through a mask 110 having a predetermined pattern, and the photosensitive resin composition constituting the photosensitive layer 20 of the portion irradiated with the actinic ray L is photocured. Then, the exposure part 22 is formed (FIG. 2C; exposure process). In this exposure step, the photosensitive layer 20 is exposed to a region other than the region on the exposed portion 50a of the circuit pattern 50. When the support 10 existing on the photosensitive layer 20 is transparent, it can be irradiated with actinic rays as it is. When the support 20 shows a light shielding property against the actinic rays, the support 20 is removed. After removal, the photosensitive layer 20 is irradiated with actinic rays.

  The mask 110 is, for example, a negative or positive mask pattern called an artwork, and includes a shielding part 110a that shields the actinic ray L and a transparent part 110b that transmits the shielding part 110a. The actinic ray L passes through only the transparent portion 110b of the mask 110 and is irradiated onto the photosensitive layer 20 in an image form. Further, as the light source of the actinic ray L, a conventionally known light source such as a carbon arc lamp, a mercury vapor arc lamp, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, or the like that can effectively emit ultraviolet rays can be used. In addition, those that effectively emit visible light, such as photographic flood bulbs and solar lamps, can also be used.

  Next, if the support 10 remains on the photosensitive layer 20, it is removed, and then wet development, dry development, etc. are performed on the photosensitive layer 20 to remove portions other than the exposed portion 22 (unexposed portions). (FIG. 2 (d); development step). As a result, a resist pattern formed from the exposed portion 22 is formed on the protective layer 60. In this developing process, the exposed portion 50a is exposed again by removing the unexposed portion.

  When the development is performed by wet development, a developer such as an alkaline aqueous solution, an aqueous developer, and an organic solvent can be used. In this case, as a developing method, methods such as spraying, rocking immersion, brushing, and scraping can be appropriately employed.

  In wet development, it is particularly preferable to use an alkaline aqueous solution because it is safe and stable and has good operability. Examples of the base of this alkaline aqueous solution include alkali hydroxides such as lithium, sodium or potassium hydroxide, alkali carbonates such as lithium, sodium, potassium or ammonium carbonate or bicarbonate, alkali metals such as calcium phosphate and sodium phosphate. Examples thereof include alkali metal pyrophosphates such as phosphate, sodium pyrophosphate and potassium pyrophosphate.

  More specifically, the alkaline aqueous developer includes, for example, a 0.1-5 wt% dilute solution of sodium carbonate, a 0.1-5 wt% dilute solution of potassium carbonate, 0.1-5 wt%. % Dilute solution of sodium hydroxide, 0.1-5% by weight dilute solution of sodium tetraborate and the like. Furthermore, the pH of the alkaline aqueous solution is preferably in the range of 9 to 11, and the temperature can be adjusted according to the developability of the photosensitive layer. In the alkaline aqueous solution, a surfactant, an antifoaming agent, a small amount of an organic solvent for promoting development, and the like may be added.

  Examples of the aqueous developer include a developer composed of water or an alkaline aqueous solution and one or more organic solvents. Here, as the base of the alkaline aqueous solution, for example, borax, sodium metasilicate, tetramethylammonium hydroxide, ethanolamine, ethylenediamine, diethylenetriamine, 2-amino-2-hydroxymethyl-1, Examples include 3-propanediol, 1,3-diaminopropanol-2, morpholine and the like. The pH of the developer is preferably as low as possible within a range where the resist can be sufficiently developed, preferably pH 8-12, more preferably pH 9-10.

  Examples of the organic solvent include triacetone alcohol, acetone, ethyl acetate, alkoxyethanol having an alkoxy group having 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono And butyl ether. These can be used alone or in combination of two or more. The concentration of the organic solvent is preferably 2 to 90% by mass, and the temperature can be adjusted according to the developability. Further, a small amount of a surfactant, an antifoaming agent or the like can be mixed in the aqueous developer. Examples of the organic solvent developer used alone include 1,1,1-trichloroethane, N-methylpyrrolidone, N, N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone.

  These organic solvents preferably add water in the range of 1 to 20% by mass in order to prevent ignition. Moreover, you may use together 2 or more types of image development methods as needed. Development methods include a dip method, a battle method, a spray method, brushing, and slapping, and the high pressure spray method is most suitable for improving the resolution.

In addition, after the development process described above, as a post-development process, heating at about 60 to 250 ° C. or exposure at about 0.2 to 10 J / cm ² is performed as necessary, and the resist pattern (exposed portion 22) is further formed It may be cured. Further, the metal surface may be etched after development, and for this, for example, a cupric chloride solution, a ferric chloride solution, an alkaline etching solution, or the like can be used.

  Then, using the protective layer 60 and the resist pattern (exposed portion 22) as a mask, electroless plating is applied to the exposed portion 50a of the circuit pattern 50 on the circuit board 80, and a plated layer 55 is formed on the surface of the exposed portion 50a. (FIG. 2 (e); plating step).

  The electroless plating can be performed, for example, by immersing the circuit board 90 with a protective layer on which a resist pattern (exposed portion 22) is formed in a plating bath. At this time, the temperature of the plating bath is preferably about 60 to 100 ° C. Examples of the electroless plating include electroless nickel plating. On the plating layer 55, metal plating such as gold, silver, palladium, platinum, rhodium, copper and tin may be further performed.

  Thereafter, the above-described resist pattern (exposed portion 22) is peeled and removed from the circuit board 90 with the protective layer, thereby obtaining the printed wiring board 100 in which the plating layer 55 is formed on the exposed portion 50a of the circuit pattern 50 (FIG. 2 (f); removal step).

  The resist pattern can be removed by, for example, processing with an aqueous solution having alkalinity stronger than that used in the development step described above. More specifically, as the strong alkaline aqueous solution, for example, a 1 to 10% by weight sodium hydroxide aqueous solution, a 1 to 10% by weight potassium hydroxide aqueous solution and the like can be applied. Further, examples of the peeling method include dipping and spraying, and these can be performed in combination.

  In the printed wiring board 100 thus obtained, the exposed portion 50a functions as a mounting pad. And the printed wiring board 100 becomes a board | substrate mounted in a portable electronic device etc. by mounting mounted components via a solder ball etc. on this mounting pad. In the present embodiment, since the plating layer 55 is formed on the mounting pad (exposed portion 50a), it is very advantageous to join the mounting components via the solder pad.

  In addition, the manufacturing method of the printed wiring board of this invention is not necessarily limited to embodiment mentioned above, You may implement it changing suitably. For example, in the above embodiment, the photosensitive layer is laminated on the protective layer of the circuit board with the protective layer via the photosensitive element. However, the present invention is not limited to this, for example, a varnish containing the photosensitive resin composition is used. You may laminate | stack by apply | coating directly on a protective layer. As the varnish and coating method, the same methods and methods as those for manufacturing the photosensitive element described above can be applied. Moreover, a through-hole etc. may be formed in a printed wiring board for multilayering.

EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples.
[Production of photosensitive element]

(Examples 1-2, Comparative Examples 1-2)
First, after mixing A component, a color former, dye, and a solvent, B component, C component, and D component were dissolved in this mixture, and the solution of the photosensitive resin composition was obtained. The amount of each component was as shown in Table 1 (units in the table indicate parts by weight).

In addition, each component in a table | surface is as follows.
A component: A copolymer obtained by copolymerizing methacrylic acid / methyl methacrylate / styrene at a weight ratio of 28/60/12 (weight average molecular weight 60,000, glass transition temperature 124 ° C., acid value 68 mgKOH / g) is methyl cellosolve / Solution dissolved in toluene mixed solvent (weight ratio 6/4) (non-volatile content 50% by weight),
B1; 2,2′-bis (4-methacryloxypentaethoxyphenyl) propane (BPE-500, manufactured by Shin-Nakamura Chemical Co., Ltd.)
B2: Polypropylene glycol / polyethylene glycol modified urethane acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.)
C1; 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer,
C2, N, N′-tetraethyl-4,4′-diaminobenzophenone,
D1; benzoguanamine; 2,4-diamino-6-phenyl-1,3,5-triazine (manufactured by Nippon Shokubai Co., Ltd.),
D2; 1,2,3-benzotriazole (BT, manufactured by Kawaguchi Chemical Industry Co., Ltd.)

Subsequently, the obtained solution of each photosensitive resin composition was uniformly applied onto a 16 μm-thick polyethylene terephthalate film (PET film, GS-16, haze: 1.7%, manufactured by Teijin Ltd.), and 100 ° C. After drying with a hot air convection dryer for 10 minutes to form a photosensitive layer, the photosensitive layer was covered with a polyethylene protective film to obtain photosensitive elements of Examples 1-2 and Comparative Examples 1-2. The film thickness of the photosensitive layer after drying was 50 μm.
[Manufacture of printed wiring boards]

(Production of circuit board with protective layer)
First, prior to the production of a printed wiring board, a circuit board with a protective layer was produced by the following method. That is, first, a 1 cm peripheral portion is left on the copper foil surface on one side of a copper clad laminate (MCL-E-679, manufactured by Hitachi Chemical Co., Ltd.), which is a glass epoxy material having a copper foil (thickness: 35 μm) on both sides. After forming an etching resist having a predetermined pattern, the copper foil was etched to remove unnecessary portions, and a circuit pattern including a mounting pad in a part was formed to obtain a circuit board.

  A photoresist (PSR-4000, manufactured by Taiyo Ink Co., Ltd.) was applied on the entire surface leaving 1 cm of the peripheral edge on the circuit pattern surface of the obtained circuit board, and then dried at 80 ° C. for 30 minutes. The entire surface of the photoresist other than the region covering the mounting pad portion was exposed through a photo tool (exposure machine: HMW-590 manufactured by Oak Manufacturing Co., Ltd.). The exposed photoresist was spray-developed using a 1% by weight aqueous sodium carbonate solution (30 ° C.), and the photoresist formed on the mounting pad was removed by removing unexposed portions. . Then, the obtained circuit board with a photoresist was processed at 150 ° C. for 1 hour to thermally cure the photoresist to form a protective layer (solder resist) on the circuit board. This obtained the circuit board with a protective layer which the mounting pad exposed.

(Preparation of printed wiring board)
Next, the printed wiring board was manufactured using the obtained circuit board with a protective layer. That is, first, the photosensitive layers in the photosensitive elements of Examples 1 and 2 and Comparative Examples 1 and 2 were laminated on the protective layers of the circuit boards with different protective layers. Specifically, each photosensitive element was disposed so that the photosensitive layer was in contact with the protective layer, and laminated at a pressure of 0.4 MPa, a temperature of 100 ° C., and a laminating speed of 1.5 m / min.

  Next, for each photosensitive layer laminated on the protective layer, the entire surface other than the region on the mounting pad is exposed and developed in the same manner as in the above-mentioned “production of circuit board with protective layer”, and only the mounting pad is developed. A resist pattern (cured product layer made of a cured product of the photosensitive resin composition) having a shape covering the protective layer was formed so as to be exposed. And the resist pattern was further hardened by heating the circuit board with the protective layer after forming the resist pattern at 150 ° C. for 1 hour, and provided on the circuit board so as to cover the entire surface other than the mounting pads. A laminate having a protective layer and a resist pattern was obtained.

  Thereafter, the following steps (a) to (l) were sequentially performed on the obtained laminates to perform electroless plating, thereby forming a plating layer on the mounting pad.

(A) Degreasing treatment The laminate was immersed in a degreasing agent (Z-200, manufactured by World Metal Co., Ltd.) at 50 ° C. for 1 minute for degreasing treatment.
(B) Washing with water The laminate was washed with running water at room temperature for 2 minutes.
(C) Soft etching The surface of the mounting pad was soft etched by immersing the laminate in a 100 g / L ammonium persulfate bath at room temperature for 1 minute.
(D) Washing with water The laminate was washed with running water at room temperature for 2 minutes.
(E) Pickling treatment Pickling was performed by immersing the laminate in a 10% sulfuric acid solution at room temperature for 1 minute.
(F) Washing with water The laminate was washed with running water at room temperature for 2 minutes.
(G) Activation The laminated board was immersed in the electroless plating catalyst solution SA-100 (manufactured by Hitachi Chemical Co., Ltd.) for 5 minutes at room temperature to activate the mounting pad.
(H) Washing with water The laminate was washed with running water at room temperature for 2 minutes.
(I) Electroless nickel plating The laminate is immersed in a Ni-P plating solution (P content 7%, NIPS-100, manufactured by Hitachi Chemical Co., Ltd.) at 80 ° C. for 20 minutes, and electroless plating is applied to the mounting pad. Went.
(J) Washing with water The laminate was washed with running water at room temperature for 2 minutes.
(K) Substitution-type electroless gold plating The laminate was immersed in Aurotech SF (manufactured by Atotech Co., Ltd.), which is a substitution-type gold plating solution, at 85 ° C. for 10 minutes to perform substitution-type electroless gold plating on the mounting pad.
(L) Post-treatment The laminate was washed with running water at room temperature for 2 minutes and then dried at 85 ° C. for 15 minutes.

  By performing electroless plating on the laminate as described above, a printed wiring board having a plating layer formed on the mounting pad was obtained. In addition, the obtained printed wiring board is a thing of the state in which the resist pattern which consists of hardened | cured material of the photosensitive resin composition remained on the protective layer.

(Evaluation of plating resistance)
The resist pattern in each printed wiring board obtained by using the photosensitive elements of Examples 1 and 2 and Comparative Examples 1 and 2 was visually observed, and the presence or absence of peeling or tearing of the resist pattern, particularly those around the mounting pad. The presence or absence was confirmed. The obtained results are shown in Table 2. In Table 2, if the resist pattern was not peeled or torn, it was marked as ○ with excellent plating resistance, and if the resist pattern was peeled or torn, it was marked with × as inferior plating resistance. It was.

(Evaluation of plating bath contamination)
Next, using the photosensitive elements of Examples 1 and 2 and Comparative Examples 1 and 2, the plating bath contamination was evaluated as described below. Hereinafter, the case where the photosensitive element of Example 1 is used will be described as an example.

That is, first, the PET film and the protective film were peeled off from the photosensitive element of Example 1 to form only a photosensitive layer, and 0.5 m ² of these were each replaced with Ni-P plating solution (P content 7%, NIPS-100, manufactured by Hitachi Chemical Co., Ltd.) at 85 ° C. for 5 hours.

  Further, using the photosensitive element of Example 1, two laminates before electroless plating were produced in the same manner as in the above-mentioned “Production of printed wiring board”. And the Ni-P plating layer was formed on the mounting pad by performing the process of said (a)-(j) with respect to the obtained laminated board, respectively. At this time, as the plating solution used in the step (i), an untreated Ni-P plating solution and the Ni-P plating solution after immersion in the photosensitive layer described above were used.

And when the untreated Ni-P plating solution was used, the thickness (T ₁ (μm)) of the plating layer obtained and when the Ni-P plating solution after immersion in the photosensitive layer was used were obtained. The thickness (T ₂ (μm)) of the plating layer was measured. By substituting these values into the following equation, the decrease rate (%) of T ₂ with respect to T ₁ was calculated. The value thus obtained was used as a numerical value indicating the plating bath contamination by the photosensitive element of Example 1. The smaller the value of the photosensitive element (photosensitive resin composition), the greater the degree of contamination of the plating bath and hindering plating.
Plating bath contamination (%) = 100 × T ₂ / T ₁

The same evaluation was performed in the same manner using the photosensitive elements of Example 2 and Comparative Examples 1 and 2, and the plating bath contamination by each photosensitive element was evaluated. The results obtained are summarized in Table 2.

  As shown in Table 2, the resist pattern (cured material layer) formed by the photosensitive elements of Examples 1 and 2 is sufficiently excellent in plating resistance and has sufficiently low plating bath contamination. Was confirmed.

It is a figure which shows typically the cross-sectional structure of the photosensitive element which concerns on embodiment. Drawing 2 is a figure showing typically the manufacturing process of the printed wiring board concerning an embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Photosensitive element, 10 ... Support body, 20 ... Photosensitive layer, 22 ... Exposure part, 30 ... Protection film, 40 ... Board | substrate, 50 ... Circuit pattern, 50a ... Exposed part, 55 ... Plating layer, 60 ... Protection layer, DESCRIPTION OF SYMBOLS 70 ... Opening part, 80 ... Circuit board, 90 ... Circuit board with a protective layer, 100 ... Printed wiring board.

Claims (9)

A binder polymer;
A photopolymerizable compound having an ethylenically unsaturated bond;
A photopolymerization initiator;
A guanamine compound represented by the following general formula (1);
A photosensitive resin composition comprising:

[Wherein, R ¹ represents a hydrogen atom, an alkyl group, or an aryl group which may have a substituent. ]   The photosensitive resin composition according to claim 1, wherein the binder polymer contains an acrylic resin containing (meth) acrylic acid and a (meth) acrylic acid alkyl ester as monomer units.   The photosensitive resin composition according to claim 1, wherein the photopolymerization initiator contains a 2,4,5-triarylimidazole dimer. The photosensitive resin composition according to claim 1, wherein the photopolymerizable compound includes a bisphenol A-based (meth) acrylate compound represented by the following general formula (2). .

[Wherein, R ²¹ and R ²² each independently represent an alkylene group having 2 to 6 carbon atoms, R ²³ and R ²⁴ each independently represent a hydrogen atom or a methyl group, and p and q are p + q = It is a positive integer satisfying 4 to 40. ]   The content of the binder polymer is 40 to 80 parts by mass, the content of the photopolymerizable compound is 20 to 60 parts by mass with respect to 100 parts by mass of the total amount of the binder polymer and the photopolymerizable compound, The content of the photopolymerization initiator is 0.1 to 20 parts by mass, and the content of the guanamine compound is 0.05 to 10 parts by mass. The photosensitive resin composition as described.   A photosensitive element comprising: a support; and a photosensitive layer made of the photosensitive resin composition according to any one of claims 1 to 5 provided on the support.   The photosensitive element according to claim 6, wherein the photosensitive layer has a transmittance of 5 to 75% for light having a wavelength of 365 nm. On the protective layer of the circuit board with a protective layer, comprising: a circuit board provided with a circuit pattern; and a protective layer that covers a surface of the circuit board so that an exposed portion from which a part of the circuit pattern is exposed is formed. A photosensitive layer forming step of forming a photosensitive layer comprising the photosensitive resin composition according to any one of claims 1 to 5;
In the photosensitive layer, an exposure step of irradiating a region other than the region on the exposed portion with an actinic ray to form an exposed portion;
A developing step of removing the region other than the exposed portion in the photosensitive layer and exposing the exposed portion;
A plating step of performing electroless plating on the exposed portion;
A removing step of removing the exposed portion;
The printed wiring board manufacturing method characterized by including this. On the protective layer of the circuit board with a protective layer, comprising: a circuit board provided with a circuit pattern; and a protective layer that covers a surface of the circuit board so that an exposed portion from which a part of the circuit pattern is exposed is formed. A photosensitive layer forming step of laminating the photosensitive layer in the photosensitive element according to claim 6 or 7,
In the photosensitive layer, an exposure step of irradiating a region other than the region on the exposed portion with an actinic ray to form an exposed portion;
A developing step of removing the region other than the exposed portion in the photosensitive layer and exposing the exposed portion;
A plating step of performing electroless plating on the exposed portion;
A removing step of removing the exposed portion;
The printed wiring board manufacturing method characterized by including this.

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