JP4428399B2 - Photosensitive resin composition used for production of printed wiring board - Google Patents

Description

  The present invention relates to a method for producing a printed wiring board and a photosensitive resin composition used therefor. In particular, the present invention relates to a method for producing a printed wiring board that can simplify the process, improve the connection reliability of mounted components, and improve the yield, and a photosensitive resin composition used therefor.

  Conventionally, in the field of manufacturing printed wiring boards, metal plating is performed on a circuit for the purpose of protecting the circuit and reducing contact resistance. In addition, with the spread of portable electronic devices, the types of mounting components used are chip scale packages (hereinafter abbreviated as CSP) and ball grid arrays (hereinafter abbreviated as CSP), which are advantageous for downsizing. (Abbreviated as BGA) is rapidly increasing. In such a mounting component, a resist is formed on the entire surface of the circuit conductor of the wiring board with a circuit excluding the mounting pad (solder pad) and the like, and the exposed pad portion and the like are subjected to metal plating. Thereafter, the mounted component and the metal plated pad are joined by a solder ball to connect the circuit-equipped wiring board to another circuit-equipped wiring board or another component. In metal plating, gold plating is often used in order to ensure good metal bonding. Gold plating is expensive and has a Mohs hardness of 2.5.

  Due to the trend toward miniaturization and higher density of printed wiring boards, and the application of metal plating technology to surface mounting of electronic components, the mainstream of metal plating is the need for electrode lead wires and a uniform plating film For reasons such as obtaining a thick and smooth surface, the electroplating is shifting to electroless plating, and particularly in a substrate for portable electronic devices. However, the printed wiring board by electroless plating method is inferior in mechanical strength due to phosphorus contained in the Ni plating layer and the bonding yield is low compared to the conventional wiring board by electrolytic plating method. We found the problem of low reliability. Furthermore, despite the low solder ball connection reliability, we have found the problem that the number of processes increases and the process becomes complicated.

  In recent years, a substrate for a portable electronic device has a problem that mounting components such as CSP and BGA are likely to drop off from the surface of the substrate due to a drop impact or bending or deflection caused by the force of pressing an input key. . As countermeasures, it has been considered to use a base material that absorbs a drop impact or the like, or to devise a method of electroless plating, but no effective countermeasures have been established yet.

  The object of the present invention is to simplify the process with a high yield by using a novel process method corresponding to the surface mounting of electronic parts that solves the above problems and achieves miniaturization and high density of the wiring board. The obtained printed wiring board has high connection reliability of mounted parts, and an improved printed wiring board manufacturing method, and suitable for use in such a manufacturing method, and has excellent plating resistance and peelability. It is providing the resin composition and its layer.

The method of the present invention is a method of manufacturing a printed wiring board,
(I) forming a solder resist on the circuit board with circuit;
(Ii) a step of laminating a layer of a previously formed photosensitive resin composition on the solder resist;
(Iii) a step of exposing and developing the layer of the photosensitive resin composition to form a resist pattern of the photosensitive resin composition;
The present invention relates to a method for producing a printed wiring board, comprising: (iv) a step of performing electroless plating on the entire surface thereof; and (v) a step of peeling off a layer of the photosensitive resin composition.

  The present invention is a photosensitive resin composition for a plating resist for performing two or more different electroless platings in printed wiring board production,

（式中、ΣＭは、該感光性樹脂組成物の固形分１kg当たりの前記反応基の総モル数であり、Ｍｉは該感光性樹脂組成物の固形分１kg当たりの光重合性化合物ｉのモル数であり、Ｎｉは光重合性化合物ｉの反応基の数であり、そしてｋは組成物中の光重合性化合物の総数である）
で示されるとき、
該感光性樹脂組成物に含まれる、分子内に重合可能なエチレン性不飽和基を有する光重合性化合物における反応基の総数ΣＭが、該感光性樹脂組成物の固形分１kg当たり、０.３〜１.５モルである、感光性樹脂組成物に関する。 The total number of moles ΣM of reactive groups in the photopolymerizable compound having an ethylenically unsaturated group polymerizable in the molecule contained in the photosensitive resin composition is represented by the formula (I):

(In the formula, ΣM is the total number of moles of the reactive group per kg solid content of the photosensitive resin composition, and Mi is the mole of photopolymerizable compound i per kg solid content of the photosensitive resin composition. And Ni is the number of reactive groups in photopolymerizable compound i and k is the total number of photopolymerizable compounds in the composition)
When indicated by
The total number of reactive groups ΣM in the photopolymerizable compound having an ethylenically unsaturated group polymerizable in the molecule contained in the photosensitive resin composition is 0.3 per 1 kg of the solid content of the photosensitive resin composition. It is related with the photosensitive resin composition which is -1.5 mol.

Hereinafter, the present invention will be described in detail.
In the present invention, the circuit board with a circuit is a circuit board with a circuit comprising a base material and a circuit (circuit conductor), may have a through-hole or the like, may have a multilayer structure, It is included in the wiring board.

  The resist is a coating material that masks or protects a specific area of the printed wiring board in order to selectively perform etching, soldering, or film formation, and also functions as a plating protective film. Usually, a photoresist is used, and a fine and accurate pattern is coated on a predetermined region with high accuracy by utilizing its photosensitivity to protect the object to be protected. In the present invention, the resist is classified into two types depending on the purpose.

  One of them is a solder resist, for example, applied so that only the region where the joint portion is formed is exposed by soldering (in other words, covers the entire surface of the circuit board with the circuit except the mounting pads). , And formed so as to have a desired coating (protection) pattern.

  The other is a resist used for the purpose of a plating resist, unlike a solder resist, and the photosensitive resin composition is used in the form of a pre-formed layer / film so that only the region where electroless plating is performed is exposed. (In other words, so as to cover the entire surface of the wiring board with a circuit where metal adhesion by plating such as a pad portion is not desirable), the molding layer / film is exposed to form a resist pattern of the photosensitive resin composition To do.

  Hereinafter, an example of the present invention will be described in more detail with reference to the drawings. As shown in FIG. 1, a solder resist 3 is formed in a region other than a mounting pad or the like (B) on a substrate with a circuit composed of a substrate 1 and a circuit 2 (B). Thereafter, a layer 4 of the photosensitive resin composition previously molded is laminated on the solder resist 3, and the layer of the photosensitive resin composition is exposed and developed to expose only a portion where electroless plating is performed. As described above (so as to cover a region where metal adhesion by plating such as a pad portion is not desirable), a resist pattern 4 ′ of the photosensitive resin composition layer is further formed for the purpose of plating resist (C). This resist pattern 4 'can then optionally be post-cured. Using the solder resist 3 and the resist pattern 4 ′ of the photosensitive resin composition layer as a mask, electroless plating 5, for example, Ni electroless plating such as Ni / Au plating, is performed on the entire surface of the resist pattern 4 ′. A plating film is formed on the surface (D), and then substitution Au plating 6 is performed (E) to obtain a plating film that is metal-plated only at a required portion. Next, the resist pattern 4 ′ of the photosensitive resin composition layer is peeled off for the purpose of plating resist (F) to obtain a printed wiring board excellent in connection reliability of mounted components.

  When the solder-resist formation step (the step (i) of the present invention) is performed before the steps such as electroless plating (the steps (ii) to (v) of the present invention) as in the method of the present invention The place where the layer of the conductive resin composition is laminated is on the solder resist. In this case, since the solder resist itself has a high light shielding property, there is no problem with respect to light leakage.

  The situation is different when using a different process sequence than the method of the present invention. For example, in this process sequence, a photosensitive resin composition layer is laminated on a circuit board, a resist pattern is formed by exposure and development, electroless Ni / Au plating is performed, and a photosensitive resin composition layer is formed. (Corresponding to steps (ii) to (v) of the present invention), and then forming a solder resist (corresponding to step (i) of the present invention). When the order of steps such as electrolytic plating is reversed from the method of the present invention, the place where the layer of the photosensitive resin composition is laminated is on a glass epoxy substrate or the like.

  Thus, when performing the formation process of a soldering resist after processes, such as an electroless plating, the place where the layer of the photosensitive resin composition is laminated | stacked will be on a glass epoxy board | substrate. Since glass epoxy substrates and the like have low light shielding properties, there is a problem in that even a photosensitive resin composition in a region that should not be exposed is exposed. That is, when the substrate is exposed from the upper surface, the light transmitted through the photosensitive resin composition layer on the upper surface of the substrate passes through the glass epoxy substrate and reaches the photosensitive resin composition layer on the lower surface of the substrate. Since this also occurs on the opposite side, a layer of the photosensitive resin composition that is unnecessarily cured is obtained, and there may be a case where a defect remaining after peeling occurs in the peeling step after electroless plating. Further, since the solder resist is formed on the gold plating surface after the electroless gold plating treatment, there is a problem that the development residue of the solder resist is likely to remain on the gold plating surface and the electrical characteristics are deteriorated.

  Therefore, in the method for producing the printed wiring board, the order of the steps is important, and the solder-resist forming step needs to be before the step such as electroless plating. As a result, a printed wiring board excellent in connection reliability of mounted components can be obtained.

  The solder resist in the present invention is not particularly limited as long as it can be used for the resist. For example, when forming a solder resist using a photoresist, after applying the photoresist on a circuit board with circuit and pre-drying, it is selectively exposed to active energy rays through a photomask and photopolymerized, It develops with a developing solution and forms the resist pattern of a soldering resist, Then, a soldering resist is formed by heating and thermosetting. Here, as a method for forming a coating film by applying a photoresist on a substrate, a known method can be used. For example, an application method can be selected as appropriate, such as screen printing, curtain coating, roll coating, and spray coating. Moreover, a solder resist can be obtained by laminating an element (photosensitive element) obtained by forming a photoresist on a film on a substrate, and exposing and developing. Similarly, a solder resist can be formed by a screen printing method or the like using a non-photosensitive solder resist.

The photosensitive resin composition (A) for the purpose of plating resist in the present invention is a photosensitive resin composition for resist for electroless plating in printed wiring board production,
The photosensitive resin composition is preferably used by laminating on a solder resist formed on a circuit board with a circuit and forming a pattern. Although the form or shape is not particularly limited, it is preferably laminated and used as a layer formed in advance on a circuit board with a circuit on which a solder resist is formed. Moreover, after apply | coating and drying with the form of a liquid composition, it can coat | cover with a protective film arbitrarily and can be used. Moreover, as a form shape | molded previously, it is preferable to use with the form of the photosensitive element which apply | coated on the support body, made it dry, and was coat | covered with the protective film arbitrarily, for example. (A) The thickness of a layer changes with uses of the printed wiring board to apply. For example, the thickness after drying is preferably about 1 to 100 μm. Moreover, it is more preferable that it is 40-75 micrometers from a viewpoint of plating tolerance. When the liquid resin composition (A) is dried and then coated with a protective film, examples of the protective film include polymer films such as polyethylene and polypropylene.

  The photosensitive resin composition (A) of the present invention contains at least one photopolymerizable compound and a photopolymerization initiator, optionally a binder polymer. Such a photopolymerizable compound is preferably one having a polymerizable ethylenically unsaturated group in the molecule.

（式中、ΣＭは、該感光性樹脂組成物の固形分１kg当たりの前記反応基の総モル数であり、Ｍｉは該感光性樹脂組成物の固形分１kg当たりの光重合性化合物ｉのモル数であり、Ｎｉは光重合性化合物ｉの反応基の数であり、そしてｋは組成物中の光重合性化合物の総数である）
で示されるとき、
該感光性樹脂組成物に含まれる、分子内に重合可能なエチレン性不飽和基を有する光重合性化合物における反応基の総数ΣＭは、めっき耐性と無電解めっき後の剥離時間のバランスを考慮すると、該感光性樹脂組成物の固形分１kg当たり、０.３〜１.５モルであることが好ましく、０.４〜１.３モルであることがより好ましく、０．５〜１．１モルであることが特に好ましい。 According to the present invention, the total number of moles ΣM of reactive groups in the photopolymerizable compound having an ethylenically unsaturated group polymerizable in the molecule contained in the photosensitive resin composition of the present invention is represented by the formula (I):

(In the formula, ΣM is the total number of moles of the reactive group per kg solid content of the photosensitive resin composition, and Mi is the mole of photopolymerizable compound i per kg solid content of the photosensitive resin composition. And Ni is the number of reactive groups in photopolymerizable compound i and k is the total number of photopolymerizable compounds in the composition)
When indicated by
The total number of reactive groups ΣM in the photopolymerizable compound having an ethylenically unsaturated group polymerizable in the molecule contained in the photosensitive resin composition is determined in consideration of the balance between plating resistance and peeling time after electroless plating. The solid content of the photosensitive resin composition is preferably 0.3 to 1.5 mol, more preferably 0.4 to 1.3 mol, and 0.5 to 1.1 mol. It is particularly preferred that

  As a photopolymerizable compound having an ethylenically unsaturated group polymerizable in the molecule used in the photosensitive resin composition (A), for example, an α, β-unsaturated carboxylic acid is reacted with a polyhydric alcohol. The resulting compound: 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolypropoxy) phenyl) propane, 2,2- Bisphenol A-based (meth) acrylate compounds such as bis (4-((meth) acryloxypolybutoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane; Compound obtained by reacting glycidyl group-containing compound with α, β-unsaturated carboxylic acid; (meth) acrylate compound having urethane bond in molecule Urethane monomers such as nonylphenoxypolyethyleneoxy (meth) acrylate; γ-chloro-β-hydroxypropyl-β ′-(meth) acryloyloxyethyl-o-phthalate, β-hydroxyalkyl-β ′-(meth) acryloyloxy Phthalic acid compounds such as alkyl-o-phthalate; (meth) acrylic acid alkyl esters and the like, and bisphenol A (meth) acrylate compounds are preferred. In particular, bisphenol A polyoxyethylene dimethacrylate; ethylene oxide, polypropylene oxide-modified urethane dimethacrylate or ethylene oxide-modified trimethylolpropane triacrylate is preferable. These can be used alone or in combination of two or more. The molecular weight of the photopolymerizable compound is preferably 1000 or more, more preferably 1500 or more, particularly preferably 2000 or more, and extremely preferably 2500 or more. These can be used alone or in combination of two or more.

  Examples of the compound obtained by reacting the polyhydric alcohol with an α, β-unsaturated carboxylic acid include, for example, polyethylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 propylene groups. Polypropylene glycol di (meth) acrylate which is ˜14, polyethylene polypropylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 14 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, tetramethylol methanetri ( And (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like. These can be used alone or in combination of two or more.

  Note that EO represents ethylene oxide, and the EO-modified compound has a block structure of an ethylene oxide group. PO represents propylene oxide, and the PO-modified compound has a block structure of propylene oxide groups.

  As the above 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) acryloxyheptaethoxy) phenyl ) Propane, 2,2-bis (4-((meth) acryloxyoctaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxynona) Toxi) 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, and 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is a BPE 500 (manufactured by Shin-Nakamura Chemical Co., Ltd., product name) and 2,2-bis (4- (methacryloxypentadecaethoxy) phenyl) propane is BPE-1300 (Shin-Nakamura Chemical) (Available from Kogyo Co., Ltd.). These can be used alone or in combination of two or more. Further, the number of ethoxy groups in the molecule is preferably 14 or more, more preferably 20 or more, and particularly preferably 25 or more. The number of intramolecular ethoxy groups is preferably 50 or less.

  As the above 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane, for example, 2,2-bis (4-((meth) acryloxydiethoxyoctapropoxy) phenyl) Examples include propane, 2,2-bis (4-((meth) acryloxytetraethoxytetrapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexaethoxyhexapropoxy) phenyl) propane, and the like. It is done. These can be used alone or in combination of two or more.

  Examples of the (meth) acrylate compound having a urethane bond in the molecule include, for example, a (meth) acryl monomer having an OH group at the β-position, isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, 1 , 6-hexamethylene diisocyanate and other diisocyanate compounds, tris ((meth) acryloxytetraethylene glycol isocyanate) hexamethylene isocyanurate, EO-modified urethane di (meth) acrylate, EO, PO-modified urethane di (meth) acrylate Etc. Examples of the EO-modified urethane di (meth) acrylate include the product name UA-11 manufactured by Shin-Nakamura Chemical Co., Ltd. Examples of EO and PO-modified urethane di (meth) acrylates include the product name UA-13 manufactured by Shin-Nakamura Chemical Co., Ltd.

  Examples of the nonylphenoxypolyethyleneoxy (meth) acrylate include nonylphenoxytetraethyleneoxy (meth) acrylate, nonylphenoxypentaethyleneoxy (meth) acrylate, nonylphenoxyhexaethyleneoxy (meth) acrylate, and nonylphenoxyheptaethyleneoxy. (Meth) acrylate, nonylphenoxyoctaethyleneoxy (meth) acrylate, nonylphenoxynonaethyleneoxy (meth) acrylate, nonylphenoxydecaethyleneoxy (meth) acrylate, nonylphenoxyundecaethyleneoxy (meth) acrylate, and the like.

  Examples of the photopolymerization initiator used in the photosensitive resin composition (A) include N, N′-tetraalkyl such as benzophenone and N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone). -4,4'-diaminobenzophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-methyl-1- (4- (methylthio) phenyl) -2- Aromatic ketones such as morpholino-propan-1-one, quinones such as alkylanthraquinones, benzoin ether compounds such as benzoin alkyl ether, benzoin compounds such as benzoin and alkylbenzoin, benzyl derivatives such as benzyldimethyl ketal, 2- (o -Chlorophenyl) -4,5-diphenylimidazole dimer, 2- ( -Chlorophenyl) -4,5-di (methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5- 2,4,5-triarylimidazole dimer such as diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, 9-phenylacridine, 1,7-bis ( And acridine derivatives such as 9,9'-acridinyl) heptane, N-phenylglycine, N-phenylglycine derivatives, and coumarin compounds. Further, the substituents of the aryl groups of two 2,4,5-triarylimidazoles may give the same and symmetric compounds, or differently give asymmetric compounds. From the viewpoint of adhesion and sensitivity, 2,4,5-triarylimidazole dimer is more preferable. These can be used alone or in combination of two or more.

  Examples of the binder polymer used in the photosensitive resin composition (A) of the present invention include acrylic resins, styrene resins, epoxy resins, amide resins, amide epoxy resins, alkyd resins, phenol resins, and the like. Is mentioned. From the viewpoint of alkali developability, an acrylic resin is preferable. These can be used alone or in combination of two or more. In the present invention, (meth) acrylic acid means acrylic acid and methacrylic acid corresponding thereto, (meth) acrylate means acrylate and corresponding methacrylate, (meth) acryloyl group means acryloyl group and The corresponding methacryloyl group is meant. Optionally, the binder polymer can have a photosensitive group.

  The binder polymer can be produced, for example, by radical polymerization of a polymerizable monomer. Examples of the polymerizable monomer include polymerizable styrene derivatives such as styrene, vinyl toluene, α-methyl styrene, p-methyl styrene, and p-ethyl styrene, acrylamide, acrylonitrile, vinyl n-butyl ether, and the like. Esters of vinyl alcohol, (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) acrylic acid, α-chloro ( (Meth) acrylic acid, β-furyl ( T) Acrylic acid, β-styryl (meth) acrylic acid, maleic acid, maleic anhydride, maleic acid monoesters such as monomethyl maleate, monoethyl maleate, monoisopropyl maleate, fumaric acid, cinnamic acid, α- Examples thereof include cyanocinnamic acid, itaconic acid, crotonic acid, and propiolic acid. These can be used alone or in combination of two or more.

  Examples of the (meth) acrylic acid alkyl ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, ( Examples include hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and structural isomers thereof. These can be used alone or in combination of two or more.

  The binder polymer preferably contains a carboxyl group from the viewpoint of alkali developability. For example, the binder polymer is produced by radical polymerization of a polymerizable monomer having a carboxyl group and another polymerizable monomer. can do. As the polymerizable monomer having a carboxyl group, methacrylic acid is preferable. The binder polymer preferably contains styrene or a styrene derivative as a polymerizable monomer from the viewpoint of film properties.

  In consideration of both adhesion and peeling properties, the above styrene or styrene derivative is used as a copolymerization component, preferably 3 to 30% by weight, more preferably 4 to 28% by weight, and more preferably 5 to 27% by weight. It is particularly preferred.

  The acid value of the binder polymer component is preferably 30 to 200 mg KOH / g, more preferably 45 to 150 mg KOH / g, considering both development time and developer resistance. Moreover, when performing solvent image development as a image development process, it is preferable to prepare the polymerizable monomer which has a carboxyl group in a small quantity.

  The weight average molecular weight (measured by gel permeation chromatography (GPC) and converted by a calibration curve using standard polystyrene) of the above binder polymer component is 20,000 to 20,000 considering both development time and developer resistance. It is preferable that it is 300,000, and it is more preferable that it is 25,000-150,000. Optionally, the binder polymer can have a photosensitive group.

  These binder polymers can be used alone or in combination of two or more. Examples of the binder polymer used in combination of two or more types include, for example, two or more types of binder polymers composed of different copolymerization components, two or more types of binder polymers having different weight average molecular weights, and two or more types of binders having different degrees of dispersion. Examples thereof include polymers. A polymer having a multimode molecular weight distribution described in JP-A No. 11-327137 can also be used.

  The photosensitive resin composition (A) of the present invention is optionally made of methanol, ethanol, acetone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether or the like. It can melt | dissolve in a solvent or these mixed solvents, and can apply | coat as a solution of about 30-60 weight% of solid content.

  The photosensitive resin composition (A) of the present invention optionally includes a photopolymerizable compound (such as an oxetane compound) having at least one cationically polymerizable cyclic ether group in the molecule, a cationic polymerization initiator, malachite green, and the like. Dyes, photochromic agents such as tribromomethylphenylsulfone, leucocrystal violet, thermochromic inhibitors, plasticizers such as p-toluenesulfonamide, pigments, fillers, antifoaming agents, flame retardants, stabilizers, leveling agents , Peeling accelerators, antioxidants, fragrances, imaging agents, thermal crosslinking agents, and the like can be added. These can be used alone or in combination of two or more.

  Further, it is preferable not to add an adhesion improver such as benztriazole and derivatives thereof, benzimidazole and derivatives thereof, and benzthiazole and derivatives thereof to the photosensitive resin composition. The reason is that when electroless plating is performed using a photosensitive resin composition layer containing an adhesion improver as a plating resist, for example, the adhesion improver is eluted in an electroless nickel plating bath, and a conductor such as copper This is because a rust preventive film is formed on the surface, and electroless nickel plating may not be deposited. In addition, it is difficult to remove the antirust coating on the conductor surface formed by this adhesion improver by pretreatment of electroless plating, so this problem can be solved by devising pretreatment of electroless plating. Difficult to do. However, such treatment of the conductor surface is important for the purpose of partially electroless Ni / Au plating and protecting the conductor surface from corrosion after the plating resist is stripped. Therefore, it is preferable to perform surface treatment using a technique such as OSP (Organic Solderability Preservative) rather than adding an adhesion improver to the layer of the photosensitive resin composition. The portion protected by the plating resist after the plating resist was peeled off was observed to be extremely corroded when electrically connected to the electroless Ni / Au partially plated conductor portion, and was derived from the potential difference between copper and gold. It is thought that corrosion. This corroded portion is not preferable because the solderability deteriorates and causes a decrease in solder connection reliability.

  The photosensitive element used in the present invention can be obtained, for example, by coating the photosensitive resin composition (A) on a polymer film such as polyethylene terephthalate, polypropylene, polyethylene, or polyester as a support and drying it. it can. The coating method can be performed by a known method such as a roll coater, a comma coater, a gravure coater, an air knife coater, a die coater, or a bar coater. Moreover, drying can be performed at about 70-150 degreeC for about 5 to 30 minutes. Further, the amount of the remaining organic solvent in the layer (A) after drying is preferably 2% by weight or less in consideration of preventing the diffusion of the organic solvent in the subsequent step. The thickness of the polymer film is preferably 1 to 100 μm.

  As the protective film for the photosensitive element of the present invention, a film similar to the support can be used. The protective film preferably has a smaller adhesive strength between the layer (A) and the protective film than the adhesive strength between the layer of the photosensitive resin composition (A) and the support, and a low fisheye film. preferable. One of these polymer films is used as a support for the (A) layer, one different type is used as the protective film for (A), the polymer films are laminated on both sides of the (A) layer, and the photosensitive element is used. Can be formed. Moreover, said photosensitive element can have intermediate | middle layers and protective layers, such as a cushion layer, an adhesive layer, a light absorption layer, and a gas barrier layer, in addition to (A) layer, a support body, and a protective film.

  The photosensitive element of the present invention, in addition to the flat plate shape as it is, for example, laminated a protective film on one side of the layer of the photosensitive resin composition (A) (on the surface that is not protected and exposed) Then, it can be wound around a cylindrical core and stored in a roll form. In addition, it is preferable to wind up so that a support body may become the outermost part at the time of storage. From the standpoint of protecting the end face, it is preferable to install an end face separator on the end face of the roll-shaped photosensitive element roll. In addition, it is more preferable to install a moisture-proof end face separator from the standpoint of edge fusion resistance. Moreover, as a packaging method, it is preferable to wrap and package in a black sheet with low moisture permeability.

  The winding core is not particularly limited. Examples thereof include plastics such as polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, ABS resin (acrylonitrile-butadiene-styrene copolymer).

When manufacturing the resist pattern of the layer of the photosensitive resin composition (A) using the photosensitive element of this invention, a protective film is removed and used in the photosensitive element with a support body and a protective film. For example, layer (A) is laminated on a wiring board on which a solder resist has been formed by heating and pressing at a pressure of about 0.1 to 1 MPa (about 1 to 10 kgf / cm ² ) while heating to about 70 to 130 ° C. It is preferable to perform lamination under reduced pressure. The surface to be laminated is usually on the solder resist surface, but is not particularly limited.

  In this way, the layer of the photosensitive resin composition (A) laminated on the wiring board with a circuit subjected to solder resist is irradiated with actinic rays through a negative or positive mask pattern to be exposed. As the actinic ray light source, a known light source such as a carbon arc lamp, a mercury vapor arc lamp, a high-pressure mercury lamp, a xenon lamp, or the like that can effectively emit ultraviolet rays and visible light can be used. A laser direct drawing exposure method can also be used.

In the present invention, the exposure is carried out using, for example, an exposure machine (HMW-590, manufactured by Oak Manufacturing Co., Ltd.) having a high-pressure mercury lamp lamp, and a stove 21 step tablet (density area 0.05 to 3.05, density). Step 0.15, step tablet size 20 mm × 175 mm, each step size 5 mm × 14 mm) is exposed with an energy amount of 8 (density 1.10). This is because when a 1% by weight aqueous sodium carbonate solution is sprayed onto the layer of the photosensitive resin composition laminated on a copper clad laminate at a pressure of 0.15 MPa over the entire surface of the photosensitive resin composition, When the minimum development time is taken as the time during which the layer is removed, the photosensitive resin composition layer laminated on another copper-clad laminate is passed through the 21-step tablet described above with actinic rays (all wavelengths in a high-pressure mercury lamp). ) Was irradiated with E (mJ / cm ² ) and sprayed with a 1% by weight aqueous sodium carbonate solution over the entire surface at a pressure of 0.15 MPa (twice the minimum development time), the number of step steps was 8 ( This is an energy amount in which the remaining area (relative to 5 mm × 14 mm) of the resist corresponding to the density 1.10) is 90% or more.

  Next, after the exposure, when the support is attached on the layer of the photosensitive resin composition (A), the support is removed with an auto peeler or the like and then developed with an alkaline aqueous solution, an aqueous developer, an organic solvent or the like. The resist pattern of the desired layer (A) can be produced by developing with wet development using a liquid or dry development. Examples of the alkaline aqueous solution include a dilute solution of 0.1 to 5% by weight sodium carbonate, 0.1 to 5% by weight potassium carbonate, and 0.1 to 5% by weight sodium hydroxide. The pH of the alkaline aqueous solution is preferably 9 to 11, and the temperature is adjusted according to the developability of the layer (A). Moreover, surfactant, an antifoamer, an organic solvent, etc. can be added and used for alkaline aqueous solution. Examples of the development method include a dip method, a spray method, brushing, and slapping.

Optionally, post-curing can be performed as the treatment after development. For example, the resist pattern of the layer of the desired photosensitive resin composition is further cured (post-cured) by heating at about 60 to 250 ° C. or further exposing at about 0.2 to 10 J / cm ^2. May be used.

  The plating of the metal terminal portion, etc., performed after development using the developed resist pattern of the photosensitive resin composition layer as a mask, for example, electroless nickel plating and replaceable electroless plating on the electroless nickel plating Plating. Examples of the displacement plating include plating containing one or more kinds of metals selected from the group consisting of gold, silver, palladium, platinum, rhodium, copper and tin. Substitutional electroless plating is one in which the metal is precipitated by the dissolution of nickel due to the difference in ionization tendency from the previously plated nickel by containing ions of the metal in the plating solution. In addition, the electroless plating containing one or more kinds of metals from among the above metals may include a reducing agent in the plating solution, along with a substitution reaction with one or more kinds of metal ions from the above metals, Among the above-mentioned metals, those containing precipitation due to a reduction reaction of one or more kinds of metal ions can also be used. For example, with the resist pattern of the developed photosensitive resin composition layer as a mask, metal plating performed after development is performed on the metal terminal portion, etc., pre-plating treatment such as degreasing treatment, soft etching, pickling treatment, activation, etc. By performing electroless nickel plating and subsequently performing electroless gold plating, electroless Ni / Au plating can be formed.

  Subsequently, the resist pattern of the layer of the photosensitive resin composition (A) for the purpose of plating resist can be peeled off with a stronger alkaline aqueous solution than the alkaline aqueous solution used for development, for example. As said strong alkaline aqueous solution, 1-10 weight% sodium hydroxide aqueous solution, 1-10 weight% potassium hydroxide aqueous solution, etc. are used, for example. Examples of the peeling method include an immersion method and a spray method. The photosensitive resin composition of the present invention is preferably peeled off after electroless plating from the viewpoint of electrical characteristics of the printed wiring board.

In addition, the circuit-attached wiring board on which the resist pattern (A) is formed may be a multilayer printed wiring board and may have a small-diameter through hole.
Usually, in a cured product of a resin composition, the storage elastic modulus E ′ and the loss elastic modulus in a viscoelastic temperature dispersion curve showing the relationship among the temperature of the cured product, the storage elastic modulus E ′, the loss elastic modulus E ″, and the loss tangent tan δ. The relationship of E ″ is as follows:
E ″ / E ′ = tanδ
Indicated by Here, in an ideal elastic body, δ = 0, and in a purely viscous fluid, δ = π / 2.

  The bridge density of the cured product is the following formula when the following conditions are satisfied:

で表される。そして、硬化物の弾性率は、下式：

It is represented by And the elastic modulus of the cured product is the following formula:

で表される。

It is represented by

unit:
Crosslink density: (mol / m ³ ); sample width, sample thickness, sample length: (mm); dynamic stress: (gf); dynamic strain: (mm); phase difference: δ (deg ); Storage modulus E ′: (Pa); loss modulus E ″ (Pa); | E ^* |: (Pa); 1 gf / mm ² = 9806 Pa; (gas constant): 8.31441 JK ⁻¹ mol ⁻¹ ; (Absolute temperature): (K)

The cured product obtained by photocuring and / or heat-curing the photosensitive resin composition (A) in the present invention has a loss when considering the resistance to the plating solution as the value of the storage elastic modulus E ′ in the viscoelastic temperature dispersion curve. It is preferably 2.0 × 10 ⁶ Pa (N / m ² ) or more at a temperature 30 ° C. to 50 ° C. higher than the peak temperature (glass transition temperature) of tangent tan δ, and 2.5 × 10 ⁶ Pa. More preferably (N / m ² ). Further, it is 2.0 × 10 ^{6 to} 8.0 × 10 ⁶ Pa (N / m ² ) at a temperature 30 ° C. to 50 ° C. higher than the peak temperature (glass transition temperature) of the loss tangent tan δ. Preferably, it is 2.5 × 10 ^{6 to} 6.0 × 10 ⁶ Pa (N / m ² ). It is preferably 2.0 × 10 ⁶ Pa (N / m ² ) or more at a temperature 40 ° C. higher than the peak temperature (glass transition temperature) of the loss tangent tan δ, and 2.5 × 10 ⁶ Pa ( N / m ² ) is more preferable.

  In addition, the photosensitive resin composition (A) of the present invention preferably has a water absorption of 8% or less, more preferably 6% or less, considering the resistance to a developer or a plating solution. It is preferably 5% or less, particularly preferably 4% or less.

  Further, the photosensitive resin composition (A) of the present invention preferably has a breaking elongation of 50% or more, preferably 70% or more, considering the ease of tearing of the cured coating film during plating. Is more preferable, 80% or more is particularly preferable, and 90% or more is particularly preferable.

  Hereinafter, the present invention will be described more specifically with reference to examples of the present invention and comparative examples thereof, but the present invention is not limited to these examples.

Synthesis of Binder Polymer In a flask equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas introduction tube, a mixed solution of ethylene glycol monomethyl ether and toluene in a weight ratio of 3: 2 (hereinafter referred to as solution A). 700 g was added, stirred while blowing nitrogen gas, and heated to 85 ° C. A solution prepared by previously mixing 110 g of methacrylic acid, 225 g of methyl methacrylate, 135 g of ethyl acrylate, 30 g of styrene and 3 g of azobisisobutyronitrile was added dropwise to solution A at a temperature of 85 ° C. over 4 hours, and then stirred at 85 ° C. The mixture was kept warm for 2 hours. Next, 60 g of the solution A was taken, 0.3 g of azobisisobutyronitrile was dissolved, and this solution was dropped into the flask over 10 minutes. Then, after stirring the obtained solution at 85 degreeC for 5 hours, stirring, it cooled and the polymer was obtained. The obtained polymer had a nonvolatile content of 41.8% by weight and a weight average molecular weight of 84,000.

  The weight average molecular weight is a value measured by a gel permeation chromatography method and converted using a standard polystyrene calibration curve.

Materials for Photosensitive Resin Composition The compounds shown below were used in the examples.
2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane (BPE-500: manufactured by Shin-Nakamura Chemical Co., Ltd.), molecular weight: 804
2,2-bis (4- (methacryloxypentadecaethoxy) phenyl) propane (BPE-1300: manufactured by Shin-Nakamura Chemical Co., Ltd.), molecular weight: 1684
EO, PO-modified urethane dimethacrylate (UA-13: Shin-Nakamura Chemical Co., Ltd.), molecular weight: 1436
EO-modified trimethylolpropane triacrylate (TA-401: manufactured by Sanyo Chemical Industries, Ltd.), molecular weight: 428
Polypropylene glycol diacrylate (APG-400: manufactured by Shin-Nakamura Chemical Co., Ltd.) (number of propylene glycol chains: 7), molecular weight: 532
Polyethylene glycol dimethacrylate (4G: manufactured by Shin-Nakamura Chemical Co., Ltd.) (number of ethylene glycol chains: 4), molecular weight: 330
Polyethylene glycol dimethacrylate (14G: manufactured by Shin-Nakamura Chemical Co., Ltd.) (number of ethylene glycol chains: 14), molecular weight: 770
Polyethylene glycol diacrylate (A-600: manufactured by Shin-Nakamura Chemical Co., Ltd.) (number of ethylene glycol chains: 14), molecular weight: 742

Example 1
(A) A solution of the photosensitive resin composition of the present invention was obtained with the material composition shown in Table 1.
(B) On a polyethylene terephthalate film (hereinafter referred to as PET) having dimensions (width 380 mm × thickness 20 μm), the solution of the photosensitive resin composition obtained in the previous step has a film thickness after drying of 50 μm. Coated so that. The film was dried at 100 ° C. using a hot air convection dryer, and a 35 μm thick polyethylene film was placed thereon, pressed with a roll, and coated to obtain the photosensitive element of the present invention.

Examples 2-12
As shown in Table 1, a photosensitive element of the present invention was obtained in the same manner as in Example 1 except that the composition of the components was changed.
Table 1 shows the formulations of the photosensitive resin compositions of Examples 1-12. In the table, the unit is parts by weight. The binder polymer showed a non-volatile weight.

Characteristic Evaluation Test Preparation Examples 1 to 8 of Characteristic Evaluation Samples
An etching resist is formed on the surface of the copper foil of a copper-clad epoxy laminate (MCL-E-67, manufactured by Hitachi Chemical Co., Ltd.) having dimensions of 12.5 cm in length, 20 cm in width, and 1.6 mm in thickness. The copper foil was removed by etching to form a metal terminal (pad) or wiring circuit, and then the remaining etching resist was removed to obtain a wiring board with circuit.
On the obtained wiring board with circuit, a photoresist (manufactured by Taiyo Ink Co., Ltd., PSR-4000) was applied on the entire surface, and then dried at 80 ° C. for 30 minutes. Thereafter, the entire surface was exposed through a mask pattern (photo tool) using an exposure machine (HMW-590, manufactured by Oak Manufacturing Co., Ltd.) except for the pad portion. The unexposed portion (pad portion) was spray-developed with a 1% by weight aqueous sodium carbonate solution (30 ° C.) to remove the photoresist on the pad portion, thereby forming a resist pattern of a solder resist. Then, it heated at 150 degreeC for 1 hour, and also was thermosetted, and the soldering resist was formed.
On the substrate on which this solder resist was formed, the photosensitive element (photosensitive layer) of Examples 1 to 8 prepared by the above method having a thickness of 50 μm was subjected to a pressure of 0.4 MPa, 100 ° C., and a laminating speed of 1.5 m / min. And then laminated. Thereafter, in the same manner as described above, the entire surface was exposed, developed, except for the pad portion, and samples 1 to 8 for characteristic evaluation covered with a layer (A layer) of the cured photosensitive resin composition were obtained. It was.

Examples 9-12
A circuit board with circuit was obtained in the same manner as in Examples 1-8. On the obtained circuit board with circuit, the photosensitive element (photosensitive layer) of Examples 9-12 having a thickness of 50 μm was pressure-bonded at a pressure of 0.4 MPa, 100 ° C. and a laminating speed of 1.5 m / min. And laminated. Thereafter, the entire surface was exposed through a photo tool except for the pad portion using an exposure machine (HMW-590, manufactured by Oak Manufacturing Co., Ltd.). The unexposed part (pad part) is spray-developed with a 1% by weight sodium carbonate aqueous solution (30 ° C.), the photoresist on the pad part is removed, and the layer of the cured photosensitive resin composition (A layer) Samples for characteristic evaluation 9 to 12 covered with the above were obtained. These characteristic evaluation samples 9 to 12 were evaluated in the same manner as in Examples 1 to 8, except for (4) plating resistance evaluation and (5) peeling characteristics.
Thereafter, a photoresist (manufactured by Taiyo Ink Co., Ltd., PSR-4000) was applied on the entire surface of the circuit board with a circuit plated with electroless Ni / Au, and then dried at 80 ° C. for 30 minutes. Thereafter, the entire surface was exposed and developed by the same method as described above, and the photoresist on the pad portion was removed to form a solder resist resist pattern. Then, it heated at 150 degreeC for 1 hour, and also was thermosetted, and the soldering resist was formed.

(1) Method for Measuring Storage Elastic Modulus E ′ of Cured Coating Film of Photosensitive Resin Composition The photosensitive element of the present invention obtained in the example was exposed to an exposure machine (HMW, manufactured by Oak Manufacturing Co., Ltd.) having a high-pressure mercury lamp. -590), the exposure was carried out with an energy amount at which the number of steps of the stove 21-step tablet was 8. After the exposure, the PET film and the polyethylene film were peeled and removed from the photosensitive element by hand, and a sample for evaluation (size 5 mm × width 40 mm × thickness 50 μm unit) consisting of a cured coating film of the photosensitive resin composition was prepared. Produced.
The test piece was fixed to a viscoelasticity measuring apparatus (manufactured by Rheometrics Co., Ltd., SOLIDS ANALYZER RSA-II) with a distance between chucks of 20 mm. Thereafter, the temperature is measured at a heating rate of 5 ° C./minute, a measurement frequency of 10 Hz, and a measurement temperature range of −50 ° C. to 250 ° C., a peak temperature of the loss tangent tan δ is obtained, E 'was determined. As an example, the viscoelastic temperature dispersion curve of Example 6 is shown in FIG. 2 (Tg = 89 ° C., E ′ _{129 ° C.} = 3.4 × 10 ⁶ (Pa)).

(2) Method for Measuring Water Absorption Rate of Cured Coating Film of Photosensitive Resin Composition A photosensitive element (photosensitive layer) is placed on a stainless steel plate having dimensions of 10 cm in length, 15 cm in width, and 1 mm in thickness, pressure 0.4 MPa, 100 A laminated piece was prepared by heat-pressing at a temperature of 1.5 ° C./min. Using an exposure machine having a high-pressure mercury lamp lamp (HMW-590, manufactured by Oak Manufacturing Co., Ltd.), a phototool having a window of 8 cm × 10 cm as a negative was placed on the laminated piece, and after development of the stove 21 step tablet The exposure was performed with an energy amount such that the number of remaining steps was 8. After the exposure, this laminate piece is allowed to stand at room temperature for 15 minutes, and then the PET is peeled and removed by hand, and developed by spraying with a 1% aqueous sodium carbonate solution (30 ° C.) from the cured coating film of the photosensitive resin composition. An 8 × 10 cm sample for evaluation was prepared.
About a test piece, the water absorption was calculated | required from the weight difference (cured coating film) before being immersed in pure water at room temperature, and after being immersed in pure water for 15 minutes.

(3) Method for measuring elongation at break of cured coating film of photosensitive resin composition Using a photosensitive element having a size of 15 mm × 100 mm and an exposure machine (HMW-590, manufactured by Oak Manufacturing Co., Ltd.) having a high-pressure mercury lamp. Then, the exposure was carried out with an energy amount at which the number of step stages of the stove 21-step tablet was eight. After exposure, the PET and polyethylene film are removed from the photosensitive element by the same method as above, and the dimensions (length 15 mm × width 100 mm × thickness 50 μm unit) consisting of a cured coating film of the photosensitive resin composition are evaluated. A sample was prepared.
The test piece was fixed to an autograph (RT-3010D-CW, manufactured by Rheotech Co., Ltd.) which is a tensile tester with a distance between chucks of 50 mm. Thereafter, a tensile test was performed in a vertical direction at a pulling speed of 2 cm / min, and elongation at break was measured.

(4) Plating resistance With respect to the obtained sample for property evaluation, the following treatment was continuously performed.
(A) Degreasing treatment Z-200 (trade name, manufactured by World Metal Co., Ltd.) is immersed for 1 minute at 50 ° C.
(B) Washing with water Wash with running water at room temperature for 2 minutes.
(C) Soft etching Immerse in a 100 g / l ammonium persulfate bath at room temperature for 1 minute.
(D) Washing with water Wash with running water at room temperature for 2 minutes.
(E) Pickling treatment The steel plate is immersed in a 10% sulfuric acid solution at room temperature for 1 minute.
(F) Washing with water Wash with running water at room temperature for 2 minutes.
(G) Activation It is immersed in a catalyst solution SA-100 for electroless plating (trade name, manufactured by Hitachi Chemical Co., Ltd.) for 5 minutes at room temperature.
(H) Washing with water Wash with running water at room temperature for 2 minutes.
(I) Electroless Nickel Plating An immersion treatment is performed at 85 ° C. for 20 minutes in NIPS-100 (trade name, manufactured by Hitachi Chemical Co., Ltd.) which is a Ni-P plating (P content 7%) solution.
(J) Washing with water Wash with running water at room temperature for 2 minutes.
(K) Substitutional type electroless gold plating Submerged type electroless gold plating solution Aurotec SF (Atotech Co., Ltd., trade name) is immersed at 85 ° C. for 10 minutes.
(L) Post-treatment After the completion of plating, the plate was washed with water and dried at 85 ° C. for 15 minutes.
The thus obtained plated evaluation sample for property evaluation was visually checked for the presence or absence of resist tearing, particularly around the pad portion.

(5) Peeling property The obtained sample for property evaluation was immersed in a 3% aqueous sodium hydroxide solution preheated to 50 ° C. The time required for the cured photosensitive resin composition to peel from the solder resist surface and the size of the peeled piece were measured.
Table 2 shows the characteristic values relating to the photosensitive resin compositions of Examples 1 to 8 and Table 3 to Examples 9 to 12 and the cured coating films obtained from the compositions. The characteristic values are calculated or measured by the above method in the amount of reactive groups ΣM of the photopolymerizable compound having a polymerizable ethylenically unsaturated group per kg solid content of the photosensitive resin composition, in the viscoelastic temperature dispersion curve. These are the storage elastic modulus E ′, water absorption, elongation at break, plating resistance, and peeling characteristics of a cured coating film at a temperature 40 ° C. higher than the peak temperature (glass transition temperature) of the loss tangent tan δ.

  As is apparent from Table 2, the wiring boards of the characteristic evaluation samples 1 to 8 produced using the methods of the present invention in Examples 1 to 8 are electrolessly plated on the mounting pad portions that do not require plating. Therefore, the connection reliability of the mounted parts was excellent.

In particular, in Examples 4 to 8 in which the photosensitive resin composition of the present invention was used in the method of the present invention, the total number of reactive groups ΣM in the photopolymerizable compound was 0.3 to 1.5 mol. When the storage elastic modulus E ′ is 2.0 × 10 ⁶ Pa (N / m ² ) or more at a temperature 40 ° C. higher than the peak temperature (glass transition temperature) of the loss tangent tan δ, the water absorption is 8% or less. The elongation at break is 50% or more, the plating resistance is excellent, it can be peeled off, the peeling time is as short as 100 seconds or less, and the peeling piece is subdivided into 30 mm or less and has excellent peeling characteristics. It was understood and showed excellent compatibility.

  Two findings are obtained from Examples 9-12. One is knowledge as a comparative example for the method of the present invention. When the process sequence in the method of the present invention was changed, light leakage occurred when exposing the photosensitive resin composition layer. For this reason, there is a part where the resist pattern is not partly peeled off, and the used resist pattern cannot be easily removed.

  Another is knowledge about the performance of the photosensitive resin composition of the present invention. The composition of the present invention was excellent in plating resistance. In addition, the reason why there was a peeling residue in the peeling characteristics was that the light was leaked and was exposed to extra light, and it was not related to the essential performance of the composition of the present invention.

  Moreover, when the sample for characteristic evaluation was created similarly to the characteristic evaluation samples 1-8 except having laminated | stacked the photosensitive element under the vacuum, the sample laminated | stacked under the vacuum rather than the lamination | stacking under a normal pressure. This improved the embedding property with respect to the unevenness on the layer lamination surface. In the evaluation of the plating resistance, the characteristic evaluation samples 1 to 4 did not change, but the number of breaks decreased. With respect to the characteristic evaluation samples 5 to 8, no breakage remained the same, but the number of blisters without breakage was eliminated, and the plating resistance was improved.

  In addition, when the characteristic evaluation sample was prepared in the same manner as the characteristic evaluation samples 1 to 8 except that the film thickness of the photosensitive resin composition (A) layer was 20 μm, the film thickness was 50 μm. When the film thickness was 20 μm, the evaluation of plating resistance was all broken, and the plating resistance was lowered.

The printed wiring board manufacturing method of the present invention uses a novel process method to adapt to surface mounting of electronic components that achieve miniaturization and high density of the wiring board, while simplifying the process, and further mounting components This is a method for manufacturing a printed wiring board that improves the connection reliability and yield. A more excellent effect can be obtained by using the photosensitive resin composition found by the present invention in the method of the present invention.
Moreover, the photosensitive resin composition of the present invention exhibits performance as an excellent protective film in electroless plating.
In the production of the printed wiring board of the present invention, the layer of the photosensitive resin composition for the electroless plating resist, which is laminated on the solder resist formed on the wiring board with circuit and patterned, is plated. Since it has excellent resistance and peelability, it improves the connection reliability and yield of mounted components.

It is a process flow schematic diagram of a printed wiring board by an example of a method of the present invention. It is a process flow schematic diagram of a printed wiring board by an example of a method of the present invention. It is a process flow schematic diagram of a printed wiring board by an example of a method of the present invention. It is a process flow schematic diagram of a printed wiring board by an example of a method of the present invention. It is a process flow schematic diagram of a printed wiring board by an example of a method of the present invention. It is a process flow schematic diagram of a printed wiring board by an example of a method of the present invention. It is a viscoelastic temperature dispersion curve figure in an example of the hardened | cured material of the photosensitive resin composition of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Circuit 3 Solder resist 4 Photosensitive resin composition layer 4 'Resist pattern of the photosensitive resin composition layer 5 Electroless Ni plating 6 Substitution Au plating

Claims (4)

A photosensitive resin composition for a plating resist for performing two or more different electroless platings in printed wiring board production,
The total number of moles ΣM of reactive groups in the photopolymerizable compound having an ethylenically unsaturated group polymerizable in the molecule contained in the photosensitive resin composition is represented by the formula (I):

(In the formula, ΣM is the total number of moles of the reactive group per kg solid content of the photosensitive resin composition, and Mi is the mole of photopolymerizable compound i per kg solid content of the photosensitive resin composition. And Ni is the number of reactive groups in photopolymerizable compound i and k is the total number of photopolymerizable compounds in the composition)
When indicated by
The total number of reactive groups ΣM in the photopolymerizable compound having an ethylenically unsaturated group polymerizable in the molecule contained in the photosensitive resin composition is 0.3 per 1 kg of the solid content of the photosensitive resin composition. 1.5 mol der is, and
At a temperature where the storage elastic modulus E ′ of the cured product of the photosensitive resin composition is 40 ° C. higher than the glass transition temperature of the cured product of the photosensitive resin composition, 2.0 × 10 ⁶ Pa (N / m ² ) or more, a photosensitive resin composition.   The photosensitive resin composition comprises at least one compound selected from the group consisting of bisphenol A polyoxyethylene dimethacrylate; ethylene oxide, polypropylene oxide modified urethane dimethacrylate, and ethylene oxide modified trimethylolpropane triacrylate. A composition according to 1. The composition of Claim 1 or 2 whose water absorption of the hardened | cured material of this photosensitive resin composition is 8% or less. The composition of any one of Claims 1-3 whose breaking elongation of the hardened | cured material of this photosensitive resin composition is 50% or more.

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