JP2002062650A - Photosensitive resin varnish, photosensitive adhesive film and printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin varnish having high reliability and photosensitivity and developable with little resin residue and to provide a photosensitive adhesive film and a printed wiring board using the film. SOLUTION: The photosensitive resin varnish contains a photo cationic polymerization initiator with tetrakispentafluorophenyl borate as an anionic species and tolylcumenyl iodonium as a cationic species, a bisphenol type epoxy novolak resin which is solid at ordinary temperature, a bisphenol type epoxy novolak resin which is liquid at ordinary temperature and methyl ethyl ketone as a solvent. The photosensitive adhesive film is obtained by volatilizing the solvent from the photosensitive resin varnish. Insulating resin build-up layers 4, 14, 6, 16 and resin soldering resist layers 8, 18 obtained by curing the photosensitive adhesive film are very high reliability layers having high moisture absorption resistance and adhesion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photosensitive resin varnish, a photosensitive adhesive film applicable to an interlayer insulating material of a printed wiring board, a permanent resist, a solder resist, and the like.
The present invention relates to a printed wiring board using the same.

[0002]

2. Description of the Related Art A multilayer printed wiring board can be manufactured by, for example, a build-up method. A multilayer printed wiring board is formed by coating a resin composition to be an interlayer film on a core substrate and forming a conductor layer thereon. . Conventionally, a resin varnish has been used for an interlayer film. In recent years, a method of laminating a resin adhesive film (dry film) formed of a resin varnish on a core substrate to simplify a manufacturing process has attracted attention.

A resin varnish is formed into a film by casting a solid resin dissolved in a volatile solvent and volatilizing the volatile solvent. For film formation, a polymer component is added so that the produced film does not excessively flow (for example, see JP-A-1-25178).
0) is known. It is also known to mix the resin with a resin having a low molecular weight so that the resin flows around the concave portion of the substrate when laminating, or to improve the cutting property of the film (for example, JP-A-6-37448).

On the other hand, to manufacture a build-up multilayer printed wiring board by a photo via process, a photosensitive resin composition is used as an interlayer insulating film and a solder resist, and vias, pads, and lands are formed by exposure and development.
The photosensitive resin composition used here is required to have not only the photosensitivity required for forming a via but also the reliability (in particular, moisture absorption resistance and high adhesion) required for a multilayer printed wiring board.
In general, a method of blending a photosensitive acrylic component and a highly reliable epoxy component in order to achieve both photosensitivity and reliability (for example, Japanese Patent Publication No. 51-40451).
Is used. From the above, a photosensitive resin adhesive film having high reliability is required.

[0005]

However, the production of a highly reliable photosensitive resin adhesive film has the following problems. As a method of forming a film that achieves both photosensitivity and reliability, a method of blending a photosensitive acrylic component and a highly reliable epoxy component cannot be used. Usually, when this method is used, two liquids are supplied, but one liquid is indispensable for film formation. In this case, there is a problem that the shelf life of the film is extremely reduced. The reason for this is not clear, but it is considered that a curing agent for curing the epoxy resin accelerates the reaction of the acrylic resin.

Further, when a polymer component is added to form a film, the developability is reduced, and the development residue (resin residue) of the resin tends to occur at the bottom of the via to be removed by development. This resin residue becomes more conspicuous as the via diameter becomes smaller, and poses a problem in reducing the via diameter as the printed wiring board becomes smaller.

SUMMARY OF THE INVENTION An object of the present invention is to provide a photosensitive resin varnish, a photosensitive adhesive film, and a printed wiring board using the same, which have high reliability and photosensitivity and are less likely to cause resin residue during development. is there.

[0008]

In order to solve the above-mentioned problems, a photosensitive resin varnish of the present invention comprises a polymer component having a molecular weight of 10,000 or more, a polymer component having a molecular weight of less than 10,000, and a solid at room temperature. A multifunctional epoxy resin component (hereinafter, also referred to as a solid epoxy resin component), an epoxy resin component that is liquid at room temperature (hereinafter, also referred to as a liquid epoxy resin component), a photocuring agent, and a solvent component. And

On the other hand, the photosensitive adhesive film of the present invention comprises a polymer component having a molecular weight of 10,000 or more, a polyfunctional epoxy resin component having a molecular weight of less than 10,000 and solid at ordinary temperature, and an epoxy resin component which is liquid at ordinary temperature. For example, the photosensitive resin varnish can be produced by casting the photosensitive resin varnish on a supporting base film and then evaporating a solvent component.

By using the photosensitive resin varnish of the present invention to exhibit photosensitivity by a system of a polyfunctional epoxy resin and a photo-curing agent which are solid at room temperature, a high shelf life can be obtained even when a film is formed, and Thus, by adding a liquid epoxy resin component, resin residue after development has been prevented or suppressed. Therefore, the photosensitive adhesive film obtained by casting the photosensitive resin varnish on a supporting base film or the like and evaporating the solvent component has excellent film characteristics, and has both high photosensitivity and high reliability. It will be. Further, when these photosensitive resin varnishes or photosensitive adhesive films are coated or laminated on a core substrate and developed by irradiation with light (for example, ultraviolet rays), almost all of the resin remains at the bottom of the via to be removed by development. This has made it possible to provide a highly reliable printed wiring board.

The support base film used for casting a photosensitive resin varnish may be made of, for example, PE or P.
VC, PET, PC, etc., release paper, copper foil, etc. can be used. These support base films may be subjected to release treatment such as application of a release agent. A protective film may be further laminated on the photosensitive adhesive film formed in a supporting base film shape. By doing so, it can be wound up on a roll and stored. The protective film includes P
E, PVC, PET, PC, release paper, and the like can be used.

The above-mentioned polymer component is a so-called thermoplastic polymer component which has a molecular weight of 10,000 or more and can be dissolved in a solvent. When the resin varnish is formed into a film, the film becomes excessively high. This prevents the fluid from flowing to the outside. Specifically, those having high compatibility with the epoxy resin, for example, phenoxy resin type, polysulfone type and the like are desirable. Above all, the phenoxy resin has high compatibility with the epoxy resin and is easily dissolved in a volatile solvent such as MEK, so that a stable varnish in which separation hardly occurs can be obtained. Polyamide resins are known as thermoplastic polymers compatible with epoxy resins.
Is not desirable because it may inhibit the cationic polymerization reaction. The molecular weight of the polymer component is preferably about 10,000 to 1,000,000, and more preferably about 10,000 to 100,000. If the molecular weight is less than 10,000, it may not be possible to effectively suppress the fluidity. If the molecular weight exceeds 1,000,000, the solubility in a solvent may be reduced, and the viscosity may be increased to decrease the fluidity, making it difficult to form a film. May be. The molecular weight referred to in the present invention is, for example, GPC (Gel PermeationCh).
It is a number average molecular weight calculated by a chromatographic method.

As a polyfunctional epoxy resin which is solid at room temperature,
A glycidyl ether type, glycidyl ester type, alicyclic or other uncured epoxy resin having a molecular weight of less than 10,000 can be mainly used. Amine type epoxy resins are known as other epoxy resins, but these are not desirable because N in the molecule inhibits the cationic polymerization reaction. Of these, a glycidyl ether type epoxy resin is particularly desirable, and specifically, an epoxy resin composed of polyphenol glycidyl ether can be mainly used.
This epoxy resin has higher moisture absorption resistance than other epoxy resins (glycidyl ester type, amine type, alicyclic type, etc.),
For example, when a photosensitive resin varnish or a photosensitive adhesive film containing the epoxy resin is used to form a resin layer of a printed wiring board, higher reliability can be obtained.

The polyphenol glycidyl ether is obtained by epoxidizing a known polyfunctional phenol compound with epihalohydrin. For example, a bisphenol-type epoxy novolak resin can be used. Specific examples of the polyfunctional phenol compound include bisphenols such as bisphenol A, F, S, and AD, and novolaks such as phenol novolak, cresol novolak, and bisphenol novolak. The polyphenol glycidyl ether may be one kind or a mixture of two or more kinds.

The bisphenol type epoxy novolak is
Specifically, a resin obtained by addition-condensing an epoxy resin having a structure represented by the following chemical formula (1) with formaldehyde is preferable. In this case, a photosensitive resin varnish or a photosensitive adhesive film having both high heat resistance and high photosensitivity is obtained.
In the formula, R1 represents —CH ₂ —, —C (CH ₃ ) ₂ —,
—CH (CH ₃ ) — or —SO ₂ —.

[0016]

Embedded image

The average number of epoxy groups in the epoxy resin of polyphenol glycidyl ether is 2-5.
Is good. If the average number of functional groups is less than 2, the heat resistance of the cured product may be reduced. If the average number of functional groups is more than 5, for example, the contrast (resolution) between the exposed portion and the unexposed portion is reduced, and fine vias and Pads may be difficult to form. Particularly preferably, it is 2.5 to 5, more preferably 2.5 to 4.
A range of 5 is good.

Here, the average number of functional groups can be determined by the formula: average number of functional groups = number average molecular weight / epoxy equivalent. The number average molecular weight is determined by GPC (Gel Perm
In the case where the epoxy resin is a mixture of two or more, the average number of functional groups is determined from the number average molecular weight of the entire mixture and the epoxy equivalent of the entire mixture.

Next, as the epoxy resin component which is liquid at room temperature, glycidyl ether type, glycidyl ester type, alicyclic epoxy resin and the like can be mainly used. Amine type epoxy resins are known as other epoxy resins, but these are not desirable because N in the molecule inhibits the cationic polymerization reaction. Particularly, glycidyl ether type epoxy resins (for example, bisphenol A type, bisphenol F type, phenol novolak type epoxy resin) are desirable. This is because the resin has higher moisture absorption resistance than other epoxy resins, and high reliability can be obtained when used for a resin layer of a printed wiring board. By the addition of the liquid resin, for example, when a film is laminated on a printed wiring board, in addition to the general effect of improving the wrapping property of the resin into the recesses of the board, the resin residue after development is reduced. An extremely important effect is exhibited in the photosensitive adhesive film.

The epoxy resin component which is liquid at normal temperature is
It can be composed mainly of an epoxy resin component having a molecular weight of 400 or less. Such a low-molecular-weight epoxy resin is a component having extremely high compatibility with the above-mentioned polymer component and with the solid multifunctional epoxy resin component. Therefore, by adding the low molecular weight epoxy resin component, the compatibility between the high molecular component and the solid epoxy resin component can be improved.

The solvent component used in the present invention is preferably one that can dissolve the polymer component and the resin component, and is easily volatilized when the varnish is cast to form a film.
For example, ketones, aromatic hydrocarbons, esters, ethers, and mixtures thereof can be used.
In particular, MEK (methyl ethyl ketone) and a mixture of MEK and another solvent are desirable from the viewpoint of volatility and toxicity. Other N-containing solvents (DMF (dimethylformamide) and NMP (N-methylpyrrolidone)) are known as solvents, but these are not desirable because N inhibits the cationic polymerization reaction.

As the photo-curing agent used in the present invention, for example, a photo-curing agent that generates an acid upon exposure and causes a polymerization reaction of the epoxy resin component by the acid can be used. Specifically, known compounds such as diazonium salts, iodonium salts and sulfonium salts can be used.
As such a photo-curing agent, a phenyl group substituted with at least one halogen selected from Cl or F is Φ1
And a general formula (1): [B (φ1) m (φ2) n] ⁻ (m is a phenyl group substituted with at least one substituent selected from F, CN, NO ₂ and CF ₃ ) 0
And n is an integer of 1 to 4 and satisfies m + n = 4).

In the present invention, the photo-curing agent can be used as a photo-cationic polymerization initiator for initiating cationic polymerization by light irradiation. Among them, the photo-curing agent having the above-mentioned anionic species is an epoxy resin. Can be polymerized in a small amount, and its photosensitivity becomes extremely high. In addition, since a small amount is used, surplus initiator components and generated acid hardly remain in the cured resin (cured product), and the reliability of the obtained cured product can be increased. It is possible to prevent or suppress a decrease in reliability.

Further, the anio represented by the above general formula (1)
The nucleophiles have low nucleophilicity, so that the polymerization termination reaction hardly occurs,
High reactivity (optical power) with any epoxy resin
(Thione polymerization initiation property). Further
Does not contain heavy metals such as Sb as anionic species.
Low toxicity and environmental protection for waste liquid and waste treatment.
Problems such as invasion hardly occur. In addition, such Anio
[B (C₆F₅)₄]⁻, [B (C₆H
₄CF₃)₄]⁻, [(C₆F₅)₂BF₂] ⁻, [C
₆F₅BF₃]⁻, [B (C₆H₃F₂)₄]⁻Use
And particularly preferred are [B (C₆F₅)
₄]⁻It is.

The cationic species of the photocuring agent can be, for example, diaryliodonium. Since diaryliodonium has an aromatic ring, it is excellent in solubility with the above epoxy resin despite being an ionic compound. Therefore, its starting efficiency is higher. In particular, those having a benzene ring skeleton having a hydrocarbon group such as an alkyl group are excellent in photosensitivity. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. The hydrocarbon group preferably has 4 or less carbon atoms. When a hydrocarbon group having a large number of carbon atoms is used, the steric hindrance may lower the initiation efficiency.

The diaryliodonium may be an asymmetric diaryliodonium in which different hydrocarbon groups are bonded to the two aryl groups in order to improve the photosensitivity. It is presumed that by breaking the symmetry of diaryliodonium, the activity against light is increased. A preferred combination of alkyl groups is a combination of a methyl group and another alkyl group. For example, methyl and ethyl, methyl and propyl, methyl and isopropyl, methyl and isobutyl, methyl and se
It is a combination of a c-butyl group, a methyl group and a tert-butyl group. Particularly preferred is a combination using a methyl group and an isopropyl group.

As the photo-curing agent which has lost the symmetry of diaryliodonium, a diaryliodonium borate (trilcumenyliodonium borate) represented by the following chemical formula (2) is particularly preferable. This is a benzene ring skeleton in which one aryl group has a methyl group (tolyl group)
Wherein the other aryl group has a combination of a benzene ring skeleton (cumenyl group) having an isopropyl group.
This photocuring agent has a high polymerization initiation efficiency and can be easily sensitized by many sensitizers (sensitizing dyes such as thioxanthones, phenothiazines, anthracenes, and ketocoumarin). Even when used as a thick film, excellent photocurability can be exhibited.

[0028]

Embedded image

In the above diaryliodonium, it is considered that electrons are localized at the iodine binding site of at least one aryl group. It is presumed that the electron localization improves the initiation efficiency of cationic polymerization. In the present invention, iodonium having an electron donating diaryl (iodonium containing an electron donating group) was employed in the present invention. It is thought that electron localization is more likely to occur, and high photosensitivity is obtained.

The photocuring agent (photoacid generator) is used in an amount of 0.1 to 100 parts by weight of the solid and liquid epoxy resin.
10 parts by weight can be contained. If the amount is less than 0.1 part by weight, sufficient photosensitivity cannot be obtained, and if the amount is more than 10 parts by weight, an excess photoacid generator remains after curing, and there is a concern that the reliability of the cured product may be reduced. is there. The preferred content of the photoacid generator is 0.1 to 5.0 parts by weight, more preferably 0.1 to 2.0 parts by weight. In the present invention, since a photocuring agent having an anionic species and a cationic species having the above structure is employed, even in the case of such a small initiator content, a varnish or a film having high photosensitivity is obtained. Therefore, it is possible to prevent or suppress the surplus initiator from remaining in the obtained printed wiring board. From such a viewpoint, the content of the initiator is 0.2 to 1.5 parts by weight, in particular, 0.5 to 1.5 parts by weight.
It is also possible to use 1.0 part by weight.

Next, the printed wiring board of the present invention comprises a polymer component having a molecular weight of 10,000 or more, a polyfunctional epoxy resin component having a molecular weight of less than 10,000 and solid at room temperature, and an epoxy resin component which is liquid at room temperature. Forming an uncured layer containing a photocuring agent,
It is characterized by having a resin layer obtained by curing it. For the uncured layer, for example, the above-described photosensitive resin varnish and / or photosensitive adhesive film can be used.

Specifically, the resin layer can be applied to a multilayer printed wiring board manufactured by a build-up method using a photo via process. in this case,
Applying the photosensitive resin varnish and / or the photosensitive adhesive film of the present invention to an interlayer insulating film and / or a solder resist,
The resin layer can be formed by exposure and development by photolithography technology, and the obtained insulating layer and / or solder resist layer of the printed wiring board have high reliability.

The photosensitive resin varnish of the present invention may contain a filler such as a silica filler, a pigment, a viscosity adjuster, a defoamer, a sensitizer, and other trace additives as required. it can.

In the present invention, the reason why the addition of a liquid epoxy resin component at room temperature reduces the resin residue after development is not clear, but is presumed as follows. Since the polymer component has a higher molecular weight than the epoxy resin component which is solid at room temperature, it has poor solubility in a developer. When the polymer component is sufficiently compatible with the solid epoxy resin component, the polymer component elutes as the solid epoxy resin component dissolves. However, if the polymer component and the epoxy resin component undergo phase separation, the polymer-rich region is difficult to be developed, and it is considered that resin residue is generated. In this case, 1 μm which is not a problem with a normal adhesive film
Even micro phase separation of about m is considered to cause resin residue.

This phase separation is more likely to occur as the molecular weight increases and the polarities differ from each other. High heat resistant epoxy resin (Chemical formula (1) etc.) to increase heat resistance by adding a polymer component for film formation
When using, it becomes easy to separate phases. Therefore, a method of selecting a solvent is generally used to reduce phase separation, but it is difficult to use this method because solvents that can be used for forming a film are limited to highly volatile solvents such as MEK.

The epoxy resin which is liquid at normal temperature has a low molecular weight (generally 400 or less), and is a component having extremely high compatibility with both the polymer component and the highly heat-resistant epoxy resin.
Therefore, the addition of this component acts in the same way as selecting an appropriate solvent (the liquid epoxy resin acts as a compatibilizing solvent), and separates the polymer component from the high heat resistant epoxy resin. It is thought to suppress.

[0037]

Embodiments of the present invention will be described below with reference to the embodiments shown in the drawings. FIG. 1 shows an example of a printed wiring board 1 according to an embodiment of the present invention.
FIG. 2 shows the cross-sectional structure. Printed wiring board 1
Is about 25 mm square and about 1 mm thick, for example, and has the following structure. That is, cores are formed in a predetermined pattern on both surfaces of a plate-shaped core material 2 made of a heat-resistant resin plate (for example, a bismaleimide-triazine resin plate) or a fiber-reinforced resin plate (for example, a glass fiber-reinforced epoxy resin). Wiring pattern layers 3 and 13 are respectively formed. These core wiring pattern layers 3 and 13 are formed so as to cover most of the surface of the core material 2 and are used as power supply layers or ground layers. On the other hand, a through-hole 12 formed by a drill or the like is formed in the core material 2, and a through-hole conductor 30 that connects the core wiring pattern layers 3 and 13 to each other is formed on the inner wall surface. The through-hole 12 is filled with a resin filling material 31 such as an epoxy resin.

On the upper layers of the core wiring pattern layers 3 and 13, first resin buildup layers 4 and 14 are respectively formed by a resin such as a photosensitive epoxy resin. Further, the first wiring pattern layers 5, 15
Are formed by Cu plating. The core wiring pattern layers 3 and 13 and the first wiring pattern layers 5 and 15
The interlayer connection is made by the via conductors 32 and 33, respectively. Similarly, second resin buildup layers 6 and 16 are formed on the first wiring pattern layers 5 and 15 by a resin such as a photosensitive epoxy resin, respectively. The second wiring pattern layers 7, 17 are formed on the surface by Cu plating, respectively. These first wiring pattern layers 5,
15 and the second wiring pattern layers 7 and 17 are interconnected by via conductors 34 and 35, respectively. In addition,
Core wiring patterns 3 and 13, first wiring pattern layers 5 and 1
The surface of each of the fifth and second wiring pattern layers 7, 17 is subjected to a surface roughening treatment (for example, based on a chemical treatment such as a blackening treatment or a chelate etching treatment) in order to increase the adhesion strength to the upper resin layer. Is given.

Next, on the second resin buildup layer 6,
A metal mark layer 9 is formed. The metal mark layer 9 has, for example, a gold plating layer (for example, a thickness of 0.04 μm) formed on the outermost surface, and for example, as shown in FIG. It includes a mark 9a, a fiducial mark 9b used for positioning the substrate, and the like. All of these have a smooth surface and a relatively strong metallic luster appearance. Further, on the second resin build-up layer 6, a large number of underlying conductive pads 10 that are electrically connected to the second wiring pattern layer 7 are provided. These underlying conductive pads 1
No. 0 is arranged in a square shape at substantially the center of the substrate by electroless Ni-P plating and Au plating, and forms a chip mounting portion 40 together with the solder bumps 11 formed thereon.

On the other hand, on the side where the second wiring pattern layer 7 is formed and on the side where the second wiring pattern layer 17 is formed, resin solder resist layers 8 and 18 covering the wiring pattern layers 7 and 17 are provided. Are formed respectively. On the wiring pattern layer 7 side, the metal mark layer 9 is exposed from the resin solder resist layer 8. Such a structure can be obtained, for example, by forming a resin solder resist layer so as to temporarily cover the entire metal mark layer, and then removing the portion of the resin solder resist layer that covers the metal mark layer.

Here, the insulating resin build-up layers 4, 1
4, 6, 16 and resin solder resist layers 8, 18
The resin material as the main component of the layer is composed of an insulating plastic material made of a cured product obtained by curing the photosensitive adhesive film of the present invention. Specifically, a photosensitive adhesive film obtained by forming the photosensitive resin varnish of the present invention into a film is laminated (laminated) in a predetermined pattern, and cured by exposure to thereby cure each of the resin layers 4, 14, 6, 16, and 8,1
8 have been obtained. In this case, a photosensitive resin is used,
Since a large number of via holes can be formed at the same time, productivity can be improved.

Specifically, the photosensitive resin varnish includes a photocationic polymerization initiator using tetrakispentafluorophenyl borate as an anionic species and trilcumenyliodonium as a cationic species, a bisphenol-type epoxy novolak resin solid at room temperature, and A resin containing a bisphenol-type epoxy novolak resin which is liquid at room temperature and methyl ethyl ketone as a solvent is employed, and the solvent is volatilized from the photosensitive resin varnish to obtain a photosensitive adhesive film. Obtained by curing such a photosensitive adhesive film,
The insulating resin build-up layers 4, 14, 6, 16 and the resin solder resist layers 8, 18 are extremely reliable with high moisture absorption resistance and adhesion.

[0043]

EXAMPLES 0.5 parts by weight of a curing agent and 0.2 parts by weight of a sensitizer were added to 100 parts by weight of the solid components of each component shown in Table 1, and diluted with MEK to prepare a photosensitive resin varnish. It was adjusted.

The following were used as the polymer component, solid and liquid epoxy resin components: E828: liquid bisphenol A type epoxy resin (Yuka Kasaku Co., Ltd.) E5051: brominated bisphenol A type epoxy resin ( Yuka Shell Co., Ltd. ・ E157S70: Bisphenol A type epoxy novolak resin (Yukaka Shell Co., Ltd.) ・ E1256: Phenoxy resin with a weight average molecular weight of 50,000 (Yukaka Shell Co., Ltd.) ・ E1010: Epoxy equivalent of 4000 Solid bisphenol A type epoxy resin (Yuka Shell Co., Ltd.) E1255HX30: Phenoxy resin with a weight average molecular weight of 100,000 (solvent cut product, solid content 30%, Yuka Shell Co., Ltd.).

(Trillcumenyl) iodonium tetrakis (pentafluorophenyl) borate (Rhone Poulin) was used as a photoacid generator, and 2,4-diethylthioxanthone (Nippon Kayaku Co., Ltd.) was used as a sensitizer.

[0046]

[Table 1]

The following evaluation was performed on these varnishes. 1. Photosensitive test Each of the photosensitive resin varnishes shown in Table 1 (Examples 1 to 4 and Comparative Examples 1 to 3) was applied on a core substrate so as to have a thickness of 50 μm, and dried at 70 ° C. for 30 minutes. . Then, using a photomask having an opening pattern with a diameter of 100 μm, irradiation with ultraviolet light having an exposure amount of 1000 mJ / cm ² was performed using a high-pressure mercury lamp. The exposed core substrate was post-baked at 80 ° C. for 30 minutes, developed with triethylene glycol dimethyl ether, and cured at 170 ° C. for 2 hours. The bottom of the via of the obtained sample was observed with a SEM to determine whether there was any resin residue.

2. Film moldability Each photosensitive resin varnish is applied on PET film,
The photosensitive adhesive film was prepared by drying at 30 ° C. for 30 minutes. The state of the obtained film was visually observed.

3. Concave wraparound property A photosensitive adhesive film obtained from each photosensitive resin varnish was adhered to a substrate having a concave section with a laminator, and the wraparound property of the film into the concave section was visually observed. A substrate having a groove having a width of 50 μm and a depth of 30 μm was used as a substrate having a concave portion.

Table 2 shows the above results.

[0051]

[Table 2]

Residual resin at the bottom of the vial was found in Comparative Examples 2 and 3 where no liquid epoxy resin was added.
In Example 4 in which the molecular weight of the phenoxy resin was large, the amount of resin residue was slightly larger than in Example 1. This is presumably because the molecular weight of the polymer component was too large, and the fluidity of the photosensitive resin varnish was excessively reduced.

The film formability was good in the system to which the polymer component was added. In Comparative Example 1, an epoxy resin having a large epoxy equivalent was used in place of the polymer component, but this caused undulation in the film, and a smooth adhesive film could not be formed.

The wraparound property of the recess was particularly good in Examples 1 to 4. In Comparative Examples 2 and 3 where no liquid epoxy resin was added, good results were obtained by optimizing the lamination conditions.

As described above, the photosensitive resin varnish of the present invention has good film formability, and the photosensitive adhesive film obtained therefrom has high photosensitivity and reliability.
It is widely used as an interlayer insulating material, a permanent resist, and a solder resist for various types of information communication printed wiring boards, including the C package.

In the present specification, the term "main component" or "main component" means a component having the highest weight content unless otherwise specified.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of a printed wiring board of the present invention.

FIG. 2 is a diagram schematically showing the cross-sectional structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed wiring board 4,14 First insulating resin buildup layer 6,16 Second insulating resin buildup layer 8,18 Resin solder resist layer

Continuing on the front page (72) Inventor Kazushige Obayashi 14-18 Takatsuji-cho, Mizuho-ku, Nagoya, Aichi Prefecture Inside Japan Specialty Ceramics Co., Ltd. (72) Inventor Yasuhiko Inui 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi, Aichi F-term in Japan Special Ceramics Co., Ltd. (reference) 2H025 AA04 AB15 AB17 AC01 AD01 BD03 BD23 BD53 BE00 BE07 BJ04 CC03

Claims (15)

[Claims] 1. A polymer component having a molecular weight of 10,000 or more, a polyfunctional epoxy resin component having a molecular weight of less than 10,000 and solid at ordinary temperature, an epoxy resin component being liquid at ordinary temperature, a photocuring agent, and a solvent component. A photosensitive resin varnish comprising: 2. The photosensitive resin varnish according to claim 1, wherein the polymer component is mainly composed of a phenoxy resin component. 3. The photosensitive resin varnish according to claim 1, wherein the polyfunctional epoxy resin component solid at room temperature is mainly composed of an epoxy resin component composed of polyphenol glycidyl ether. 4. The photosensitive resin varnish according to claim 1, wherein the polyfunctional epoxy resin component which is solid at room temperature is mainly composed of a bisphenol-type epoxy novolak resin component. 5. The photosensitive resin varnish according to claim 1, wherein an average number of epoxy groups contained in the polyfunctional epoxy resin component solid at room temperature is 2 to 5. 6. The epoxy resin component which is liquid at normal temperature,
The photosensitive resin varnish according to any one of claims 1 to 5, wherein the varnish mainly comprises an epoxy resin component having a molecular weight of 400 or less. 7. The photo-curing agent, wherein a phenyl group substituted with at least one halogen selected from Cl or F is Φ1, and F, CN, NO ₂ , C
A phenyl group substituted with at least one substituent selected from F ₃ is defined as Φ2, and a general formula: [B (Φ1) m (Φ2) n] ⁻ (m is an integer of 0 to 3 and n is 1 to 4 The photosensitive resin varnish according to any one of claims 1 to 6, wherein the varnish has an anionic species represented by the following formula: 8. The photosensitive resin varnish according to claim 1, wherein the cationic species of the photocuring agent is diaryliodonium. 9. A composition comprising a polymer component having a molecular weight of 10,000 or more, a polyfunctional epoxy resin component having a molecular weight of less than 10,000 and solid at room temperature, an epoxy resin component liquid at room temperature, and a photo-curing agent. Characteristic photosensitive adhesive film. 10. A photosensitive adhesive film produced by casting the photosensitive resin varnish according to claim 1 on a supporting base film and then evaporating a solvent component. 11. An uncured material containing a polymer component having a molecular weight of 10,000 or more, a polyfunctional epoxy resin component having a molecular weight of less than 10,000 and solid at room temperature, an epoxy resin component liquid at room temperature, and a photo-curing agent. A printed wiring board, wherein a resin layer is formed by forming a layer and curing the layer. 12. The varnish according to claim 1, wherein the uncured layer is made of the photosensitive resin varnish according to claim 1. Description:
The printed wiring board as described. 13. The printed wiring board according to claim 11, wherein the uncured layer is made of the photosensitive adhesive film according to claim 9. 14. The printed wiring board according to claim 11, wherein the resin layer is an insulating layer and / or a solder resist layer. 15. The printed wiring board according to claim 11, wherein said resin layer is patterned by a photolithography technique.