JP2019185025A - Photosensitive resin composition, dry film, cured product and printed wiring board - Google Patents

Abstract

To provide a photosensitive resin composition excellent in a coating property and a film forming property as well as excellent in developability and resolution and capable of improving productivity of a dry film.SOLUTION: The photosensitive resin composition of the present invention comprises a carboxyl group-containing resin A having a weight average molecular weight of 1500 or more and less than 5000, a carboxyl group-containing resin B having a weight average molecular weight of 5000 or more and 150000 or less, an epoxy resin, a photopolymerization initiator, a photosensitive monomer, and an inorganic filler, in which a compounding ratio of the carboxyl group-containing resin A to the carboxyl group-containing resin B is 6:4 to 3:7 on a mass basis, and the content of the inorganic filler is 40 to 300 parts with respect to 100 parts of the carboxyl group-containing resin included in the photosensitive resin composition.SELECTED DRAWING: None

Description

The present invention relates to a photosensitive resin composition, and more specifically, relates to a photosensitive resin composition that is excellent in coating property and film forming property and has high developability and resolution.
The present invention also relates to a dry film, a cured product, and a printed wiring board using the photosensitive resin composition.

  In general, in printed wiring boards used for electronic devices, etc., in order to prevent solder from adhering to unnecessary parts, and to prevent circuit conductors from being exposed and corroded by oxidation or moisture, circuit pattern formation A solder resist is formed in the region excluding the connection holes on the substrate.

  One of the methods for forming a solder resist having a desired pattern on a substrate is a method using a photolithography technique. Specifically, an alkali-developable photosensitive resin composition is applied on a substrate and dried. Then, after forming the coating film, after exposing through the pattern mask, by performing alkali development using the difference in solubility in the alkaline developer of the exposed and unexposed areas, a solder resist having a desired pattern is obtained. Can be formed.

In recent years, electronic devices tend to be smaller, lighter, higher performance, and multifunctional. Following these trends, printed circuit boards can be used for wiring circuits such as L / S thinning and I / O count increase. The density of external connection terminals is increasing.
In particular, the connection method between the semiconductor chip and the printed wiring board tends to shift from the wire bonding connection method to the flip chip connection method in order to cope with the increase in the number of I / Os.

In order to perform high-density mounting in the flip-chip connection method, it is necessary to form a small-diameter flip chip pad on a solder resist together with high-density wiring circuits. Therefore, the photosensitive resin composition is required to have a performance capable of forming a solder resist having a small-diameter opening pattern with high accuracy and high density.
In order to satisfy this performance, in addition to good developability and resolution of the photosensitive resin composition, smooth film thickness accuracy of the solder resist surface is required.
In order to realize these, the solder resist is being transferred from a liquid to a dry film type (for example, Patent Document 1).

In general, a solder resist dry film is produced by coating and drying a photosensitive resin composition on a support film conveyed at a constant speed.
More specifically, the photosensitive resin composition is applied to a support film with a uniform thickness using a coating machine, and then the support film coated with the photosensitive resin composition is used as a dryer. By passing through, the dry film is produced by drying so that the amount of the residual solvent in the applied coating liquid becomes an appropriate value.

  In recent years, in order to improve the productivity of dry film, it has been carried out to increase the coating speed of the photosensitive resin composition, but when the conventional photosensitive resin composition is coated on a support film at a high speed, Problems that cause problems include film breaks and bubble generation. The term “film break” as used herein refers to a phenomenon in which the coating liquid to be uniformly applied on the support film cannot sufficiently follow, and partially breaks off during the coating. , Refers to the following two types of foam. The first is foam generated when air is entrained at the contact point between the discharge portion of the coating liquid and the support film to be transported, and the second is a step of drying the solvent contained in the coating liquid. It is a foam left in the coating liquid when it is dried and volatilized. In particular, since bubbles due to the volatilization of the solvent are smaller in size than bubbles formed by entraining air, it takes time to defoam and break bubbles from the generation of bubbles. Because of these problems, there is room for improvement in coating properties and film forming properties.

As a conventional solution, in order to improve the film breakage, there is a method in which the solvent content in the coating liquid is reduced to increase the viscosity and decrease the fluidity, thereby coating the support film to be transported without gaps. In order to improve foam, there is a method to increase the solvent content in the coating liquid to lower the viscosity and increase the fluidity, thereby making it easier for the foam to move to the interface between the coating liquid and the gas phase. .
However, these methods are contradictory and cannot be combined. Furthermore, with regard to the improvement of the above-mentioned foam, when the drying time is adjusted to a certain standard, the amount of the solvent remaining in the coating film increases, so that the tack becomes strong and the handling property in the subsequent substrate manufacturing process is deteriorated. Invite. In addition, when the residual solvent amount of the coating film is adjusted to a certain standard, the drying time becomes longer, so it takes a lot of heat history, and the life of the dry film is shortened and the productivity is deteriorated. Further problems arise.

JP 2011-13486 A

The present inventors now use a carboxyl group-containing resin having a weight average molecular weight in a specific numerical range at a specific blending ratio, and use an inorganic filler for 100 parts of the carboxyl group-containing resin contained in the photosensitive resin composition. Thus, the present inventors have found that the inclusion of 40 to 300 parts can significantly improve the coating property, film forming property, developability and resolution of the photosensitive resin composition.
The present invention has been made on the basis of the above knowledge, and the problems to be solved are excellent in coating property and film forming property, excellent in developability and resolution, and improved in productivity of dry film. The photosensitive resin composition which can be made to provide is provided.

  The photosensitive resin composition according to the present invention includes a carboxyl group-containing resin A having a weight average molecular weight of 1500 or more and less than 5000, a carboxyl group-containing resin B having a weight average molecular weight of 5000 or more and 150,000 or less, an epoxy resin, Including a photopolymerization initiator, a photosensitive monomer, and an inorganic filler, and the mixing ratio of the carboxyl group-containing resin A and the carboxyl group-containing resin B is 6: 4 to 3: 7 on a mass basis, Content of the said inorganic filler is 40-300 parts with respect to 100 parts of carboxyl group-containing resin contained in the photosensitive resin composition, It is characterized by the above-mentioned.

  In the embodiment of the present invention, the photosensitive resin composition preferably contains an acyl phosphine oxide photopolymerization initiator as a photopolymerization initiator.

  Moreover, in embodiment of this invention, it is preferable that the photosensitive resin composition contains at least one of barium sulfate and spherical silica as an inorganic filler.

  A dry film according to another aspect of the present invention has a resin layer obtained by applying the photosensitive resin composition to a support film and drying.

  A cured product according to another aspect of the present invention is obtained by curing the photosensitive resin composition or the resin layer of the dry film.

  The printed wiring board by another aspect of this invention has the said hardened | cured material, It is characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in coating property and film forming property, it is excellent in developability and resolution, The photosensitive resin composition which can improve the productivity of a dry film can be provided.

  Hereinafter, the photosensitive resin composition of the present invention will be described. Unless otherwise specified, in this specification, a numerical range represented using the symbol “to” includes a range including upper and lower limits (that is, a range not less than the lower limit and not more than the upper limit). , “Part” means part by mass, and “%” means mass%. Unless otherwise specified, the content of each component is converted to solid content.

[Photosensitive resin composition]
The photosensitive resin composition of the present invention includes a carboxyl group-containing resin A having a weight average molecular weight of 1500 or more and less than 5000, a carboxyl group-containing resin B having a weight average molecular weight of 5000 or more and 150,000 or less, an epoxy resin, It contains a photopolymerization initiator, a photosensitive monomer, and a specific amount of inorganic filler.
Moreover, the photosensitive resin composition can contain at least 1 sort (s) of a thermosetting catalyst, a coloring agent, and a diluent.
Hereinafter, each component contained in the photosensitive resin composition will be described in detail.

[Carboxyl group-containing resin]
As the carboxyl group-containing resin, various conventionally known resins having a carboxyl group in the molecule can be used. When the photosensitive resin composition contains a resin having a carboxyl group, alkali developability can be imparted to the photosensitive resin composition. In particular, a carboxyl group-containing resin having an ethylenically unsaturated double bond in the molecule is preferable in terms of photocurability and development resistance. The ethylenically unsaturated double bond is preferably derived from acrylic acid or methacrylic acid or derivatives thereof. When only a carboxyl group-containing resin having no ethylenically unsaturated double bond is used, the composition is sensitized by using a compound having a plurality of ethylenically unsaturated groups in the molecule described later, that is, a photosensitive monomer. Sexually.

The photosensitive resin composition according to the present invention includes a carboxyl group-containing resin A having a weight average molecular weight of 1500 or more and less than 5000, a carboxyl group-containing resin B having a weight average molecular weight of 5000 or more and 150,000 or less, and a blending ratio (mass). Standard) 6: 4 to 3: 7. By including the carboxyl group-containing resin A and the carboxyl group-containing resin B in the above-mentioned range in the above blending ratio in the above blending ratio, the coating property and the film forming property are excellent, and the photosensitivity is excellent in developability and resolution. Resin composition can be obtained. The reason for this is not necessarily clear, but is assumed to be as follows.
That is, by including a carboxyl group-containing resin having a large weight average molecular weight in the photosensitive resin composition, the fluidity of the resin composition can be lowered, and film breakage hardly occurs when applied at high speed. Therefore, the film forming property can be improved. On the other hand, due to the fluidity in the drying process after coating, bubbles that are generated when the solvent in the coating solution volatilizes worsen and remain in the coating solution, or foam is applied. It may take time to reach the interface between the liquid and the gas phase, resulting in poor leveling after bubble breaking. Furthermore, since it is difficult to dissolve in a developing solution during development in the substrate manufacturing process, there is a concern that the resin is likely to remain between the bottom of the opening and the pattern.
Therefore, in addition to the carboxyl group-containing resin having a large weight average molecular weight, the photosensitive resin organism contains a carboxyl group-containing resin having a small weight average molecular weight, and further, the blending ratio is set to a specific numerical range. Since the fluidity of the resin composition can be adjusted, the film breakage can be improved and the defoaming effect can be improved as compared with the case of only the carboxyl group-containing resin having a large weight average molecular weight. As a result, it is possible to obtain a photosensitive resin composition that is excellent in coating property and film forming property, and excellent in both developability and resolution.
However, this is only an estimation area and is not necessarily limited to this.
The photosensitive resin composition may contain at least one of two or more kinds of carboxyl group-containing resins A and two or more kinds of carboxyl group-containing resins B.
In the present invention, “weight average molecular weight” means a value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance, and is a method based on JIS-K-7252-1 (issued in 2008). Can be measured.

From the viewpoint of coating property, film-forming property, developability and resolution of the photosensitive resin composition, the weight average molecular weight of the carboxyl group-containing resin A is preferably 1600 or more and 4500 or less, preferably 1800 or more, More preferably, it is 4000 or less.
Further, from the viewpoints of coating property, film forming property, developability and resolution of the photosensitive resin composition, the weight average molecular weight of the carboxyl group-containing resin B is preferably 6000 or more and 100,000 or less, and 7000. As mentioned above, it is more preferable that it is 50000 or less.

  Specific examples of the carboxyl group-containing resin include the following compounds (any of oligomers and polymers).

  (1) A carboxyl group-containing resin obtained by copolymerization of an unsaturated carboxylic acid such as (meth) acrylic acid and an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth) acrylate, and isobutylene.

  (2) Diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates; carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, polycarbonate polyols, and polyethers A carboxyl group-containing urethane resin by a polyaddition reaction of a diol compound such as a polyol, a polyester polyol, a polyolefin polyol, an acrylic polyol, a bisphenol A alkylene oxide adduct diol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

  (3) Diisocyanate and bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin ( A carboxyl group-containing photosensitive urethane resin obtained by polyaddition reaction of (meth) acrylate or a partially acid anhydride modified product thereof, a carboxyl group-containing dialcohol compound, and a diol compound.

  (4) During the synthesis of the resin of the above (2) or (3), a compound having one hydroxyl group and one or more (meth) acryloyl groups in a molecule such as hydroxyalkyl (meth) acrylate is added, and the terminal ( (Meth) acrylic carboxyl group-containing photosensitive urethane resin.

  (5) During the synthesis of the resin of (2) or (3), one isocyanate group and one or more (meth) acryloyl groups are added in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate. A carboxyl group-containing photosensitive urethane resin obtained by adding a compound having a terminal (meth) acrylate.

  (6) A carboxyl group-containing photosensitive resin obtained by reacting a bifunctional or higher polyfunctional (solid) epoxy resin with (meth) acrylic acid and adding a dibasic acid anhydride to a hydroxyl group present in the side chain.

  (7) A carboxyl obtained by reacting (meth) acrylic acid with a polyfunctional epoxy resin obtained by epoxidizing the hydroxyl group of a bifunctional (solid) epoxy resin with epichlorohydrin and adding a dibasic acid anhydride to the resulting hydroxyl group Group-containing photosensitive resin.

  (8) Two bases such as phthalic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride are reacted with a dicarboxylic acid such as adipic acid, phthalic acid, and hexahydrophthalic acid by reacting the bifunctional oxetane resin. A carboxyl group-containing polyester resin to which an acid anhydride is added.

  (9) An epoxy compound having a plurality of epoxy groups in one molecule, a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule such as p-hydroxyphenethyl alcohol, and (meth) Reacting with an unsaturated group-containing monocarboxylic acid such as acrylic acid, and then reacting with the alcoholic hydroxyl group of the resulting reaction product, maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, adipine A carboxyl group-containing photosensitive resin obtained by reacting a polybasic acid anhydride such as an acid.

  (10) Reaction obtained by reacting an unsaturated group-containing monocarboxylic acid with a reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide. A carboxyl group-containing photosensitive resin obtained by reacting a product with a polybasic acid anhydride.

  (11) Reaction obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with a reaction product obtained by reacting a cyclic carbonate compound such as ethylene carbonate or propylene carbonate with an unsaturated group-containing monocarboxylic acid. A carboxyl group-containing photosensitive resin obtained by reacting a product with a polybasic acid anhydride.

(12) A carboxyl group-containing photosensitive resin obtained by adding a compound having one epoxy group and one or more (meth) acryloyl groups in one molecule to the resins (1) to (11).
In addition, in this specification, (meth) acrylate is a term which generically refers to acrylate, methacrylate and a mixture thereof, and the same applies to other similar expressions.

  The acid value of the carboxyl group-containing resins A and B is preferably 40 to 200 mgKOH / g, and more preferably 50 to 160 mgKOH / g. By making the acid value of the carboxyl group-containing resin within the above numerical range, the developability of the photosensitive resin composition can be improved, and dissolution of the exposed portion by the developer can be prevented.

  These carboxyl group-containing resins are not limited to those listed above, and one kind thereof may be used alone, or a plurality of kinds may be mixed and used. Among them, a carboxyl group-containing resin synthesized by using a compound having a phenolic hydroxyl group such as the carboxyl group-containing resins (10) and (11) as a starting material is excellent in HAST resistance and PCT resistance. it can.

[Photopolymerization initiator]
The photosensitive resin composition includes a photopolymerization initiator, and as the photopolymerization initiator, an acylphosphine oxide photopolymerization initiator, an oxime ester photopolymerization initiator having an oxime ester group, α-aminoacetophenone-based light Examples include a polymerization initiator, a titanocene photopolymerization initiator, a benzoin compound, an acetophenone compound, an anthraquinone compound, a thioxanthone compound, a ketal compound, a benzophenone compound, a tertiary amine compound, and a xanthone compound. Among these, it is preferable that it is an acyl phosphine oxide type photoinitiator from a viewpoint of the resolution of the photosensitive resin composition.

  Examples of the acylphosphine oxide photopolymerization initiator include bisacylphosphine oxide photopolymerization initiators and monoacylphosphine oxide photopolymerization initiators. Specifically, bis- (2,6-dichlorobenzoyl) phenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) ) -4-propylphenylphosphine oxide, bis- (2,6-dichlorobenzoyl) -1-naphthylphosphine oxide, bis- (2,6-dimethoxybenzoyl) phenylphosphine oxide, bis- (2,6- Dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,5-dimethylphenylphosphine oxide, bis- (2,4,6-trimethylbenzoyl)- Phenylphosphine oxide, 2,6-dimethoxy Benzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphinic acid isopropyl ester 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl-2,4,6-trimethylbenzoylphenylphosphinate, (2,6-dimethoxybenzoyl) -2,4,4-pentylphosphine oxide, etc. It is done.

As the acyl phosphine oxide photopolymerization initiator, an acyl phosphine oxide photopolymerization initiator represented by the following general formula (I) can be used.
Wherein R1 and R2 are each independently a halogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a linear or branched alkoxy group having 1 to 6 carbon atoms, carbon An aryl group having 6 to 20 carbon atoms which may be substituted with at least one of a cycloalkyl group having 5 to 20 atoms, an alkyl group and an alkoxy group, or at least one of an alkyl group and an alkoxy group. Represents an arylcarbonyl group having 7 to 20 carbon atoms which may be substituted with a seed.)

Examples of the halogen atom include fluorine, chlorine, bromine, iodine and the like.
Examples of the linear or branched alkyl group having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, t-butyl, pentyl, and hexyl groups.
Examples of the linear or branched alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, and a hexyloxy group.
Examples of the cycloalkyl group having 5 to 20 carbon atoms include a cyclopentyl group, a cyclohexyl group, and those in which these cycloalkyl groups are substituted with an alkyl group, an alkoxy group, or the like.
Examples of the aryl group having 6 to 20 carbon atoms which may be substituted with at least one of the alkyl group and the alkoxy group include a phenyl group, a naphthyl group, and an aryl group such as an alkyl group and an alkoxy group. The thing substituted by at least any 1 type is mentioned.
The arylcarbonyl group having 7 to 20 carbon atoms which may be substituted with at least one of the above alkyl group and alkoxy group is A- (C = O)-(A is the alkyl group or alkoxy group. Represents an aryl group which may be substituted with at least one of them, and specific examples include a benzyl group and a trimethylbenzyl group.

  As the acyl phosphine oxide-based photopolymerization initiator, commercially available products may be used. Examples thereof include Omnirad TPO, Omnirad TPO-L, LR8953X, Omnirad 819 manufactured by IGM Resins.

  The content of the acylphosphine oxide photopolymerization initiator in the photosensitive resin composition is preferably 0.1 to 20 parts with respect to 100 parts of the carboxyl group-containing resin contained in the photosensitive resin composition. More preferably, it is 5-18 parts, and 1-15 parts is still more preferable. By making content of the acyl phosphine oxide type photoinitiator in the photosensitive resin composition into the said numerical range, the photocurability of the photosensitive resin composition by this invention can be improved more. Moreover, chemical resistance etc. of hardened | cured material etc. which are formed using this photosensitive resin composition can be improved.

  The photosensitive resin composition may contain a photopolymerization initiator other than the acylphosphine oxide photopolymerization initiator (hereinafter referred to as other photopolymerization initiator), and the content of the other photopolymerization initiator. From the viewpoint of the resolution of the photosensitive resin composition, it is preferably 1 part or less and preferably 0.5 part or less with respect to 100 parts of the carboxyl group-containing resin contained in the photosensitive resin composition. More preferably, it is particularly preferable not to include it.

[Epoxy resin]
Examples of epoxy resins that can be used include bisphenol A type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins, brominated bisphenol A type epoxy resins, bisphenol S type epoxy resins, and phenol novolac type epoxies. Resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin, bisphenyl-phenol type epoxy resin, modified novolak Type epoxy resin and the like.
These epoxy resins may be used individually by 1 type, and may be used in combination of 2 or more type.

  As commercially available epoxy resins, for example, jER 828, 806, 807, YX4000, YX8000, 8034, 834 manufactured by Mitsubishi Chemical Corporation, YD-128, YDF-170, ZX- manufactured by Nippon Steel Chemical & Material Co., Ltd. 1059, ST-3000, EPICLON 830, 835, 840, 850 manufactured by DIC Corporation, N-770, N-870, N-730A, N-695, and RE-306, NC-3000H manufactured by Nippon Kayaku Co., Ltd. Etc. As these epoxy resins, those that are liquid at normal temperature (20 ° C.) may be used alone, those that are solid at normal temperature may be used alone, or two or more of liquid and solid are used in combination. Also good. Among these, those that are used in a liquid state at normal temperature (20 ° C.) or those that use a combination of liquid and solid are preferable.

  The content of the epoxy resin in the photosensitive resin composition is such that the number of functional groups of the thermosetting component that reacts is 0.5 to 2 with respect to 1 mol of carboxyl groups contained in the carboxyl group-containing resin contained in the photosensitive resin composition. 5 mol is preferable, and 0.8 to 2.0 mol is more preferable.

[Photosensitive monomer]
Examples of the compound used as the photosensitive monomer include conventionally known polyester (meth) acrylate, polyether (meth) acrylate, urethane (meth) acrylate, carbonate (meth) acrylate, epoxy (meth) acrylate, and the like.

Specifically, hydroxyalkyl acrylate compounds such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; diacrylate compounds of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; N, N-dimethylacrylamide Acrylamide compounds such as N-methylol acrylamide and N, N-dimethylaminopropyl acrylamide; aminoalkyl acrylate compounds such as N, N-dimethylaminoethyl acrylate and N, N-dimethylaminopropyl acrylate; hexanediol, trimethylolpropane, Polyhydric alcohols such as pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyanurate or the like Polyethylene acrylate compounds such as ethylene oxide adducts, propylene oxide adducts, or ε-caprolactone adducts; phenoxy acrylate, bisphenol A diacrylate, and ethylene oxide adducts or propylene oxide adducts of these phenol compounds. And polyvalent acrylate compounds of glycidyl ethers such as glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate.
Not limited to the above, acrylate compounds and melamine acrylates in which polyols such as polyether polyols, polycarbonate diols, hydroxyl-terminated polybutadienes, and polyester polyols are directly acrylated or urethane acrylated via diisocyanate, and each methacrylate corresponding to the acrylate Any one of the compounds can be appropriately selected and used.

  A polyfunctional epoxy resin such as a cresol novolac type epoxy resin, an epoxy acrylate resin obtained by reacting acrylic acid, and a hydroxyl group of the epoxy acrylate resin, a hydroxy urethane such as pentaerythritol triacrylate and a diisocyanate half urethane such as isophorone diisocyanate. An epoxy urethane acrylate compound or the like obtained by reacting the compound may be used as the photosensitive monomer. Such an epoxy acrylate resin can improve photocurability without deteriorating the touch drying property.

  The content of the photosensitive monomer in the photosensitive resin composition is preferably 5 to 50 parts and more preferably 10 to 40 parts with respect to 100 parts of the carboxyl group-containing resin contained in the photosensitive resin composition. preferable. By setting the content of the photosensitive monomer in the photosensitive resin composition within the above numerical range, the resolution of the photosensitive resin composition can be further improved.

[Inorganic filler]
The photosensitive resin composition by this invention is characterized by including 40-300 parts of inorganic fillers with respect to 100 parts of carboxyl group-containing resin contained in the photosensitive resin composition. When the photosensitive resin composition contains a specific blending amount of the inorganic filler, the physical strength of the cured product formed from the photosensitive resin composition can be improved. In addition, an effect can be expected to improve the foam of the present invention. The reason for this is not necessarily clear, but is assumed to be as follows.
When bubbles generated by volatilization of the solvent in the photosensitive resin composition reach the interface between the coating liquid and the gas phase and break the bubbles, bubbles are easily broken by including an inorganic filler. The reason is that when the affinity between the resin and the solvent contained in the photosensitive resin composition is compared with the affinity between the inorganic filler and the solvent, the affinity between the inorganic filler and the solvent is lower and incompatible. Because the interface state of the bubbles can be destabilized due to the incompatible state, bubble breakage is promoted. As a result, since the process is promptly performed from the generation of bubbles to the breakage of bubbles, the leveling property after the breakage is improved. However, this is only an estimation area and is not necessarily limited to this.

Examples of the inorganic filler include silicon oxides such as talc, amorphous silica, crystalline silica, fused silica and spherical silica, titanium oxide, aluminum oxide, calcium oxide, magnesium oxide, zinc oxide, calcium carbonate, magnesium carbonate, fly ash, Dehydrated sludge, natural silica, synthetic silica, kaolin, clay, calcium hydroxide, aluminum hydroxide, magnesium hydroxide, mica, hydrotalcite, aluminum silicate, magnesium silicate, calcium silicate, calcined talc, wollastonite, titanic acid Potassium, magnesium sulfate, calcium sulfate, magnesium phosphate, sepiolite, zonolite, boron nitride, aluminum borate, silica balloon, glass flake, glass balloon, silica, iron slag, copper, iron, iron oxide, sender DOO, alnico magnet, the magnetic powder of various ferrites such as cement, glass powder, Noiburugu siliceous earth, diatomaceous earth, antimony trioxide, magnesium oxysulfate, hydrated aluminum, hydrated gypsum, alum and barium sulfate and the like.
Among the above, it is preferable to contain at least one of spherical silica and barium sulfate from the viewpoint of improving the physical strength of the cured product or the like, and these may be used in combination.

    As the spherical silica, any spherical silica that can be used as an inorganic filler for electronic materials can be used. One kind may be used alone, or two or more kinds may be used in combination. Further, the shape of the spherical silica may be spherical and is not limited to a true sphere. In order to improve dispersibility, the spherical silica is preferably surface-treated with a coupling agent or the like.

Examples of suitable spherical silica include, but are not limited to, those having a sphericity measured as follows of 0.8 or more.
In the present invention, the sphericity of spherical silica is measured as follows.
First, a photograph of spherical silica was taken with a scanning electron microscope (SEM), and from the area and perimeter of particles observed on the photograph, (sphericity) = {4π × (area) ÷ (perimeter) ² }.
In the present invention, the sphericity is obtained for 100 spherical silicas, and the average value thereof is defined as the sphericity.

The average particle diameter of the spherical silica is preferably 300 to 1000 nm, and more preferably 500 to 900 nm.
In the present invention, the average particle diameter of the spherical silica is not only the particle diameter of the primary particles but also the average particle diameter (D50) including the particle diameter of the secondary particles (aggregates). It is the value of D50 measured. An example of a measurement apparatus using a laser diffraction method is Microtrac MT3300EXII manufactured by Microtrack Bell Co., Ltd. Note that the maximum particle size (D100) and the particle size (D10) can be measured in the same manner using the above-described apparatus.

    The method for producing spherical silica is not particularly limited, and methods known to those skilled in the art can be applied. For example, it can be manufactured by burning silicon powder by a VMC (Vaporized Metal Combustion) method. In the VMC method, a chemical flame is formed by a burner in an oxygen-containing atmosphere, and metal powder that constitutes part of the target oxide particles is introduced into the chemical flame in such an amount that a dust cloud is formed. In this method, deflagration is caused to obtain oxide particles. Commercially available spherical silica may be used. Examples of commercially available spherical silica include SO-C2, SO-E2, and SO-E3 manufactured by Admatechs Corporation, SFP-20M and SFP-30M manufactured by Denka Corporation.

    The surface treatment method of the spherical silica is not particularly limited, and a known and commonly used method may be used. However, the surface treatment agent having a curable reactive group, for example, a coupling agent having a curable reactive group as an organic group, etc. It is preferable to treat the surface.

    In addition, the surface-treated spherical silica may be contained in the photosensitive resin composition of the present invention in a surface-treated state, and the surface-untreated spherical silica and the surface treatment agent are separately blended. Although spherical silica may be surface-treated in the composition, it is preferable to blend spherical silica that has been surface-treated in advance. By blending the spherical silica that has been surface-treated in advance, it is possible to suppress a decrease in crack resistance or the like due to the surface treatment agent that has not been consumed by the surface treatment that may remain when blended separately. In the case of surface treatment in advance, it is preferable to blend a pre-dispersion in which spherical silica is pre-dispersed in a solvent or curable component. Pre-dispersing the surface-treated spherical silica in a solvent and blending this pre-dispersion into the composition Alternatively, it is more preferable that the pre-dispersed liquid is blended into the composition after sufficiently surface-treating when the surface-untreated spherical silica is pre-dispersed in the solvent.

    The spherical silica may be blended in a powder or solid state depending on the usage mode of the photosensitive resin composition of the present invention, or may be blended after mixing with a solvent or a dispersant to form a slurry.

    Any known barium sulfate can be used, and at least one selected from hydroxides and oxides of one or more metal elements selected from Al, Si and Zr is used as barium sulfate. The surface treatment may be performed by adhering to the surface. Specific examples of the surface treatment agent include hydrous silicic acid, hydrous amorphous silicon dioxide, aluminum hydroxide, zirconium oxide and organosilane compounds. Examples of commercially available barium sulfate include precipitated barium sulfate # 100, precipitated barium sulfate # 300, precipitated barium sulfate SS-50, BARIACE B-30, BARIACE B-31, and BARIACE manufactured by Sakai Chemical Industry Co., Ltd. B-32, BARIACE B-33, BARIACE B-34, BARIFINE BF-1, BARIFINE BF-10, BARIFINE BF-20, BARIFINE BF-40, W-1, W-6, W made by Takehara Chemical Co., Ltd. -10, C-300 and the like. One kind may be used alone, or two or more kinds may be used in combination. Furthermore, the photosensitive resin composition in the present invention may appropriately contain generally mentioned organic fillers in addition to the inorganic fillers.

    The content of the inorganic filler contained in the photosensitive resin composition in the present invention is 40 to 300 parts and 50 to 300 parts with respect to 100 parts of the carboxyl group-containing resin contained in the photosensitive resin composition. preferable. When the content of the inorganic filler is 40 parts or more, the coating property and the film forming property become better. Moreover, a line pattern shape becomes it more favorable that it is 300 parts or less. Furthermore, by making it into the said numerical range, physical strength, such as hardened | cured material, can be improved, maintaining the viscosity of the photosensitive resin composition favorable.

[Thermosetting catalyst]
The photosensitive resin composition by this invention can contain a thermosetting catalyst, and can improve the storage stability and heat resistance of the photosensitive resin composition by this.

Examples of the thermosetting catalyst include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- Imidazole derivatives such as (2-cyanoethyl) -2-ethyl-4-methylimidazole; dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy-N, N-dimethylbenzyl Examples include amines, amine compounds such as 4-methyl-N, N-dimethylbenzylamine, hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide, and phosphorus compounds such as triphenylphosphine.
Also, guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino S-triazine derivatives such as -S-triazine / isocyanuric acid adduct and 2,4-diamino-6-methacryloyloxyethyl-S-triazine / isocyanuric acid adduct can also be used as the thermosetting catalyst.
Examples of commercially available thermosetting catalysts include 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, 2P4MHZ (both trade names of imidazole compounds) manufactured by Shikoku Kasei Kogyo Co., Ltd., and U-CAT manufactured by San Apro Co., Ltd. 3513N (trade name of dimethylamine compound), DBU, DBN, U-CAT SA 102 (both are bicyclic amidine compounds and salts thereof), and the like.

    The content of the thermosetting catalyst contained in the photosensitive resin composition is preferably 1 to 30 parts and preferably 5 to 20 parts with respect to 100 parts of the carboxyl group-containing resin contained in the photosensitive resin composition. Is more preferable. By setting the content of the thermosetting catalyst within the above numerical range, the storage stability and heat resistance of the photosensitive resin composition can be further improved.

[Colorant]
The photosensitive resin composition may contain a colorant. As the colorant, known colorants such as red, blue, green and yellow can be used, and any of pigments, dyes and pigments may be used. However, it is preferable not to contain a halogen from the viewpoint of reducing the environmental burden and affecting the human body.

    Examples of the red colorant include monoazo, disazo, azo lake, benzimidazolone, perylene, diketopyrrolopyrrole, condensed azo, anthraquinone, quinacridone, and the like. -Indexes (CI; Issued by The Society of Dyersand Colors) are listed.

    Examples of the monoazo red colorant include Pigment Red 1, 2, 3, 4, 5, 6, 8, 9, 12, 14, 15, 16, 17, 21, 22, 23, 31, 32, 112, 114, 146, 147, 151, 170, 184, 187, 188, 193, 210, 245, 253, 258, 266, 267, 268, 269 and the like. Examples of the disazo red colorant include Pigment Red 37, 38, and 41. Examples of the monoazo lake red colorant include Pigment Red 48: 1, 48: 2, 48: 3, 48: 4, 49: 1, 49: 2, 50: 1, 52: 1, 52: 2, 53: 1, 53: 2, 57: 1, 58: 4, 63: 1, 63: 2, 64: 1, 68 and the like. Examples of the benzimidazolone red colorant include Pigment Red 171, 175, 176, 185, 208 and the like. Examples of the perylene red colorant include Solvent Red 135, 179, Pigment Red 123, 149, 166, 178, 179, 190, 194, 224, and the like. Examples of the diketopyrrolopyrrole red colorant include Pigment Red 254, 255, 264, 270, and 272. Examples of the condensed azo red colorant include Pigment Red 220, 144, 166, 214, 220, 221, 242 and the like. Examples of the anthraquinone red colorant include Pigment Red 168, 177, 216, Solvent Red 149, 150, 52, 207, and the like. Examples of the quinacridone red colorant include Pigment Red 122, 202, 206, 207, and 209.

    Examples of blue colorants include phthalocyanine and anthraquinone, and pigments include compounds classified as Pigment. For example, Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 60. Solvent Blue 35,63,68,70,83,87,94,97,122,136,67,70 etc. can be used as a dye system. In addition to the above, a metal-substituted or unsubstituted phthalocyanine compound can also be used.

Examples of the yellow colorant include monoazo, disazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone. Examples of the anthraquinone yellow colorant include Solvent Yellow 163, Pigment Yellow 24, 108, 193, 147, 199, 202 and the like. Examples of the isoindolinone-based yellow colorant include Pigment Yellow 110, 109, 139, 179, 185, and the like. As the condensed azo yellow colorant, Pigment Yellow
93, 94, 95, 128, 155, 166, 180 and the like. Examples of the benzimidazolone yellow colorant include Pigment Yellow 120, 151, 154, 156, 175, 181 and the like. Examples of the monoazo yellow colorant include Pigment Yellow 1, 2, 3, 4, 5, 6, 9, 10, 12, 61, 62, 62: 1, 65, 73, 74, 75, 97, 100, 104, 105, 111, 116, 167, 168, 169, 182, and 183. Examples of the disazo yellow colorant include Pigment Yellow 12, 13, 14, 16, 17, 55, 63, 81, 83, 87, 126, 127, 152, 170, 172, 174, 176, 188, 198, and the like. Is mentioned.

    In addition, colorants such as purple, orange, brown, and black may be added. Specifically, Pigment Black 1, 6, 7, 8, 9, 10, 11, 12, 13, 18, 20, 25, 26, 28, 29, 30, 31, 32, Pigment Violet 19, 23, 29 32, 36, 38, 42, Solvent Violet 13, 36, C.I. I. Pigment Orange 1, 5, 13, 14, 16, 17, 24, 34, 36, 38, 40, 43, 46, 49, 51, 61, 63, 64, 71, 73, Pigment Brown 23, 25, carbon black, etc. Is mentioned.

    The content of the colorant in the photosensitive resin composition is preferably 0.1 to 10 parts, preferably 0.1 to 5 parts, with respect to 100 parts of the carboxyl group-containing resin contained in the photosensitive resin composition. It is more preferable. By setting the content of the colorant in the photosensitive resin composition within the above numerical range, the resolution of the photosensitive resin composition and the circuit concealing property of a cured product formed thereby can be improved.

[Organic solvent]
The photosensitive resin composition according to the present invention may contain an organic solvent to form a coating solution, whereby the viscosity of the photosensitive resin composition can be adjusted. Moreover, content of the organic solvent in the photosensitive resin composition can be suitably changed according to the material which comprises the photosensitive resin composition.
The organic solvent that can be used is not particularly limited, and examples thereof include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents, and the like. be able to. More specifically, ketones such as methyl ethyl ketone (MEK) and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, Glycol ethers such as propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, diethylene glycol monoethyl ether acetate (carbitol acetate), dipropylene glycol methyl Ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate Esters such as propylene glycol butyl ether acetate; Alcohols such as ethanol, propanol, ethylene glycol, propylene glycol; Aliphatic hydrocarbons such as octane and decane; Petroleum such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha Solvent. Such an organic solvent may be used individually by 1 type, and may be used in combination of 2 or more type.

    Volatile drying of organic solvents is supported by a hot-air circulating drying furnace, IR furnace, hot plate, convection oven, etc. (using a steam-heated heat source with a steam source in countercurrent contact with hot air in the dryer and nozzles) Can be performed using a method of spraying on the body).

[Others]
The photosensitive resin composition can contain a well-known and usual additive in the range which does not impair the characteristic of this invention. For example, initiation aid, cyanate compound, elastomer, mercapto compound, urethanization catalyst, thixotropic agent, adhesion promoter, block copolymer, chain transfer agent, polymerization inhibitor, copper damage inhibitor, antioxidant, rust prevention Agents, fine silica, organic bentonite, montmorillonite and other thickeners, silicone-based, fluorine-based, polymer-based antifoaming agents and leveling agents, imidazole-based, thiazole-based, triazole-based silanes Examples include a flame retardant such as a coupling agent, a phosphinate, a phosphoric ester derivative, and a phosphorus compound such as a phosphazene compound.

[Usage]
The photosensitive resin composition by this invention can be used conveniently for formation of the soldering resist layer of a printed wiring board, and can be used suitably especially for formation of the soldering resist layer for IC packages. The photosensitive resin composition according to the present invention may be one-component or two-component or more.

[Dry film]
The photosensitive resin composition of this invention can also be made into the form of the dry film provided with the support film and the resin layer which consists of the said photosensitive resin composition formed on this support film. When forming a dry film, the photosensitive resin composition of the present invention is diluted with the above organic solvent to adjust to an appropriate viscosity, and is applied to a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater. A film can be obtained by applying a uniform thickness on a support film with a gravure coater, spray coater or the like, and drying usually at a temperature of 50 to 130 ° C. for 1 to 30 minutes. Although there is no restriction | limiting in particular about a coating film thickness, Generally, it is 1-150 micrometers by the film thickness after drying, Preferably it selects suitably in the range of 5-60 micrometers.

    The support film can be used without particular limitation as long as it is a known film. For example, a thermoplastic film such as a polyester film such as polyethylene terephthalate or polyethylene naphthalate, a polyimide film, a polyamideimide film, a polypropylene film, or a polystyrene film. The film which consists of can be used conveniently. Among these, a polyester film is preferable from the viewpoint of heat resistance, mechanical strength, handleability, and the like. Moreover, the laminated body of these films can also be used as a support film.

    The thermoplastic resin film as described above is preferably a film stretched in a uniaxial direction or a biaxial direction from the viewpoint of improving mechanical strength.

    Although the thickness of a support film is not specifically limited, For example, it can be 10-150 micrometers.

    After forming the resin layer of the photosensitive resin composition of the present invention on the support film, the protective layer (cover) that can be peeled off from the surface of the resin layer for the purpose of preventing dust from adhering to the surface of the resin layer. ) It is preferable to laminate films. As the peelable protective film, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, a surface-treated paper, etc. can be used, and when the protective film is peeled off, the adhesive force between the resin layer and the support film As long as the adhesive strength between the resin layer and the protective film is smaller.

    Although the thickness of a protective film is not specifically limited, For example, it can be 10-150 micrometers.

[Cured product]
The cured product of the present invention is obtained by curing the above-described photosensitive resin composition or the above-described dry film.

[Printed wiring board]
The printed wiring board of the present invention has a cured product obtained from the photosensitive resin composition of the present invention or the resin layer of the dry film. As a method for producing a printed wiring board of the present invention, for example, the photosensitive resin composition of the present invention is adjusted to a viscosity suitable for a coating method using the organic solvent, and a dip coating method is performed on a substrate. After coating by a method such as a flow coating method, a roll coating method, a bar coater method, a screen printing method, or a curtain coating method, the organic solvent contained in the composition is volatilized and dried (temporary drying) at a temperature of 60 to 100 ° C. Thus, a tack-free resin layer is formed. In the case of a dry film, the resin layer is formed on the substrate by peeling the support film after laminating the substrate so that the resin layer is in contact with the substrate.

    Examples of the base material include printed wiring boards and flexible printed wiring boards that have been previously formed with copper or the like, paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, glass cloth / paper epoxy. It is made of materials such as copper-clad laminates for high-frequency circuits using synthetic fiber epoxy, fluororesin, polyethylene, polyphenylene ether, polyphenylene oxide, cyanate, etc., and copper-clad laminates of all grades (FR-4 etc.) Examples thereof include a plate, a metal substrate, a polyimide film, a polyethylene terephthalate film, a polyethylene naphthalate (PEN) film, a glass substrate, a ceramic substrate, and a wafer plate.

    The bonding of the dry film onto the substrate is preferably performed under pressure and heating using a vacuum laminator or the like. By using such a vacuum laminator, when a circuit-formed substrate is used, even if there are irregularities on the circuit board surface, the dry film adheres to the circuit board, so there is no mixing of bubbles, The filling property of the recesses on the substrate surface is also improved. The pressurizing condition is preferably about 0.1 to 2.0 MPa, and the heating condition is preferably 40 to 120 ° C.

    Volatile drying performed after applying the photosensitive resin composition of the present invention is performed in a dryer using a hot air circulation drying furnace, an IR furnace, a hot plate, a convection oven or the like (equipped with a heat source of an air heating method using steam). The method can be carried out using a method in which hot air is brought into countercurrent contact and a method in which the hot air is blown onto the support.

    After the resin layer is formed on the substrate, it is selectively exposed with active energy rays through a photomask having a predetermined pattern, and the unexposed area is diluted with a dilute alkaline aqueous solution (for example, 0.3 to 3% sodium carbonate aqueous solution) Develop to form a cured product pattern. In the case of a dry film, after exposure, the support film is peeled off from the dry film and developed to form a cured product patterned on the substrate. In addition, if it is a range which does not impair a characteristic, a support film may be peeled from a dry film before exposure, and the exposed resin layer may be exposed and developed.

    Furthermore, the cured product is irradiated with active energy rays and then heat-cured (for example, 100 to 220 ° C.), irradiated with active energy rays after heat-curing, or subjected to final finish curing (main-curing) only by heat-curing, thereby allowing adhesion. A cured film having excellent properties such as properties and hardness is formed.

As an exposure machine used for the active energy ray irradiation, a high-pressure mercury lamp lamp, an ultra-high pressure mercury lamp lamp, a metal halide lamp, a mercury short arc lamp, and the like may be used as long as the apparatus irradiates ultraviolet rays in a range of 350 to 450 nm. Furthermore, a direct drawing apparatus (for example, a laser direct imaging apparatus that directly draws an image with a laser using CAD data from a computer) can also be used. The lamp light source or laser light source of the direct drawing machine may have a maximum wavelength in the range of 350 to 450 nm. The amount of exposure for image formation varies depending on the film thickness and the like, but is generally 10 to 1000 mJ / cm ² , preferably 20 to 800 mJ / cm ² .

    The developing method can be a dipping method, a shower method, a spray method, a brush method, etc., and as a developing solution, potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, Alkaline aqueous solutions such as ammonia and amines can be used.

    EXAMPLES Next, although an Example is given and this invention is demonstrated still in detail, this invention is not limited to these Examples.

<Synthesis of carboxyl group-containing resin A>
In an autoclave equipped with a thermometer, a nitrogen introduction device / alkylene oxide introduction device, and a stirring device, 152.8 parts of a novolac-type cresol resin (trade name “Shonol CRG951”, manufactured by Aika Industry Co., Ltd., OH equivalent: 119.4) Then, 1.52 parts of potassium hydroxide and 152.8 parts of toluene were charged, the inside of the system was replaced with nitrogen while stirring, and the temperature was increased.

Next, 81.7 parts of propylene oxide was gradually added dropwise and reacted for 16 hours under the conditions of 125 to 132 ° C. and 0 to 4.8 kg / cm ² to obtain a reaction solution. Thereafter, the reaction solution was cooled to room temperature, and 2 parts of 89% phosphoric acid was added to and mixed with the reaction solution to neutralize potassium hydroxide. The nonvolatile content was 62.1% and the hydroxyl value was 182.2 g / eq. A novolak-type cresol resin propylene oxide reaction solution was obtained. This was an average of 1.08 moles of alkylene oxide added per equivalent of phenolic hydroxyl group.

    375.0 parts of an alkylene oxide reaction solution of the obtained novolac-type cresol resin, 55.3 parts of acrylic acid, 14.8 parts of methanesulfonic acid, 0.23 parts of methylhydroquinone and 323.7 parts of toluene were mixed with a stirrer, temperature A reactor equipped with a meter and an air blowing tube was charged, air was blown at a rate of 10 ml / min, and the reaction was carried out at 110 ° C. for 12 hours while stirring. As the water produced by the reaction, 16.1 parts of water distilled as an azeotrope with toluene.

    Thereafter, the mixture was cooled to room temperature, and the resulting reaction solution was neutralized with 45.2 parts of a 15% aqueous sodium hydroxide solution and then washed with water.

    Thereafter, toluene was distilled off while substituting 151.2 parts of diethylene glycol monoethyl ether acetate with an evaporator to obtain a novolak acrylate resin solution.

    Next, 425.6 parts of the obtained novolak acrylate resin solution and 1.56 parts of triphenylphosphine were charged into a reactor equipped with a stirrer, a thermometer and an air blowing tube, and air was supplied at a rate of 10 ml / min. Then, 77.8 parts of tetrahydrophthalic anhydride was gradually added with stirring, reacted at 95 to 101 ° C. for 6 hours, cooled, and taken out. The carboxyl group-containing resin A thus obtained had a non-volatile content of 70.6% and a solid acid value of 87.7 mgKOH / g. Moreover, it was 2400 when the weight average molecular weight of carboxyl group-containing resin A was measured by the gel permeation chromatography (GPC) by using polystyrene based on JIS-K-7252-1 (issued in 2008) as a standard substance. Hereinafter, this carboxyl group-containing resin solution is referred to as varnish A.

<Synthesis of carboxyl group-containing resin B>
A flask equipped with a condenser and a stirrer was charged with 583.7 parts of bisphenol A, 291.8 parts of water, and 830.7 parts of 37% formalin, and maintained at a temperature of 40 ° C. or lower. Part was added and reacted at 50 ° C. for 10 hours.

    After completion of the reaction, the reaction mixture was cooled to 40 ° C and neutralized to pH 4 with a 37.5% phosphoric acid aqueous solution while maintaining the temperature at 40 ° C or lower. Thereafter, the mixture was allowed to stand to separate the aqueous layer. After separation, methyl isobutyl ketone was added and dissolved uniformly, then washed three times with distilled water, and water, solvent and the like were removed under reduced pressure at a temperature of 50 ° C. or lower.

    The obtained polymethylol compound was dissolved in 704 parts of methanol to obtain 1574.4 parts of a methanol solution of the polymethylol compound. When a part of the methanol solution of the obtained polymethylol compound was dried at room temperature in a vacuum dryer, the solid content was 55.2%.

A flask equipped with a condenser and a stirrer was charged with 640 parts of the methanol solution of the polymethylol compound obtained above and 563.2 parts of 2,6-xylenol and uniformly dissolved at 50 ° C. After dissolving uniformly, methanol was removed under reduced pressure at a temperature of 50 ° C. or lower.
Thereafter, 10.2 parts of oxalic acid was added and reacted at 100 ° C. for 10 hours. After completion of the reaction, the distillate was removed under reduced pressure at 180 ° C. and 50 mmHg to obtain 704 parts of novolak resin A.

In an autoclave equipped with a thermometer, a nitrogen introduction device / alkylene oxide introduction device, and a stirring device, 166.4 parts of novolak resin A, 3.3 parts of 50% aqueous sodium hydroxide solution, toluene / methyl isobutyl ketone (mass ratio = 2/1) ) 120 parts were charged, the inside of the system was purged with nitrogen while stirring, and then the temperature was raised by heating, and 57.6 parts of ethylene oxide was gradually introduced and reacted under the conditions of 150 ° C. and 8 kg / cm ² . The reaction was continued for about 4 hours until the gauge pressure reached 0.0 kg / cm ^2, and then cooled to room temperature.

    To this reaction solution, 4.2 parts of 36% hydrochloric acid aqueous solution was added and mixed to neutralize sodium hydroxide. The neutralized reaction product was diluted with toluene, washed three times with distilled water, and the solvent was removed with an evaporator. The hydroxyl value was 175 g / eq. An ethylene oxide adduct of novolak resin A was obtained. This was an average of 1 mole of ethylene oxide added per equivalent of phenolic hydroxyl group.

    224 parts of ethylene oxide adduct of the obtained novolak resin A, 64 parts of acrylic acid, 3.8 parts of p-toluenesulfonic acid, 0.13 part of hydroquinone monomethyl ether, and 166.4 parts of toluene were stirred, thermometer, air A reactor equipped with a blowing tube was charged, stirred while blowing air, heated to 115 ° C., and reacted for another 4 hours while distilling off the water produced by the reaction as an azeotrope with toluene. Cooled to room temperature.

    The obtained reaction solution was washed with 5% NaCl aqueous solution and toluene was removed by distillation under reduced pressure, and then diethylene glycol monoethyl ether acetate was added to obtain an acrylate resin solution having a nonvolatile content of 68%.

    Next, a four-necked flask equipped with a stirrer and a reflux condenser was charged with 399.4 parts of the obtained acrylate resin solution, 0.13 parts of hydroquinone monomethyl ether, and 0.38 parts of triphenylphosphine, and this mixture. Was heated to 110 ° C., 57.6 parts of tetrahydrophthalic anhydride was added, allowed to react for 4 hours, cooled and taken out. The carboxyl group-containing resin B thus obtained had a nonvolatile content of 72% and a solid content acid value of 65 mgKOH / g. Moreover, it was 13000 when the weight average molecular weight of carboxyl group-containing resin B was measured by gel permeation chromatography (GPC) using polystyrene based on JIS-K-7252-1 (issued in 2008) as a standard substance. Hereinafter, the solution of the carboxyl group-containing resin B is referred to as varnish B.

[Examples 1-7 and Comparative Examples 1-6]
Each component described in Table 1 below was premixed with a stirrer in the ratio (parts by mass) shown in Table 1, and then kneaded with a three-roll mill to prepare a photosensitive resin composition. In addition, the value of the compounding quantity in a table | surface shows the mass part of solid content, as long as there is no special description.

<Evaluation of coatability and film formability>
Methyl ethyl ketone was added to the photosensitive resin compositions prepared in the above Examples and Comparative Examples to appropriately dilute the solid content to 50%, and stirred with a stirrer for 15 minutes to obtain a coating solution.
Using a coating machine on a polyethylene terephthalate film having a thickness of 25 μm (Lumirror T60 manufactured by Toray Industries, Inc.), the coating speed (6 m / min, 9 m / min, 12 m / min) described above is used. After coating the coating solution, it was dried to produce a dry film having a thickness of 20 μm.
The coating film on the surface of the dry film was visually observed, and the coating property and film forming property of the photosensitive resin composition were evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1.
After the evaluation, a polypropylene film having a thickness of 18 μm (OPP-FOA manufactured by Futamura Chemical Co., Ltd.) was bonded to a dry film produced at a coating speed of 12 m / min using a roll laminator, and used for the evaluation described below. .
(Evaluation criteria)
◯: Good coating property and film forming property without film breakage and bubbles were confirmed.
X: A small amount of film breakage or bubbles were confirmed.
XX: Film breakage and bubbles were confirmed.

<Line pattern shape evaluation>
For Examples 1 to 7 and Comparative Example 5 in which good results were obtained in the above-described coating property and film forming property evaluation, test substrates were prepared in order to perform line pattern shape evaluation. Specifically, a HL832 NS substrate (manufactured by Mitsubishi Gas Chemical Co., Ltd., with copper foil removed by etching) was prepared, and a dry film polypropylene produced at a coating speed of 12 m / min in coating / film forming evaluation. The film was peeled off, and the exposed dry film and the substrate were bonded together. Subsequently, using a vacuum laminator (MVLP-500 manufactured by Meiki Seisakusho Co., Ltd.), the degree of pressure was 0.8 Mpa, 80 ° C., 1 minute, Vacuum lamination was performed under the condition of 133.3 Pa, and the substrate and the dry film were adhered to each other.
Next, using an exposure device equipped with a high-pressure mercury lamp (short arc lamp), a pattern is formed with an optimal exposure amount from a polyethylene terephthalate film surface side through a photomask having a line pattern with a width of 30 to 100 μm and a space with a width of 100 μm. After the exposure, the polyethylene terephthalate film was peeled off.
After peeling, development was performed for 90 seconds under the conditions of 30 ° C. and a spray pressure of 0.2 MPa using a 1% aqueous sodium carbonate solution for patterning.
Next, after irradiating the patterned dry film with an exposure amount of 1 J / cm 2 in a UV conveyor furnace equipped with a high-pressure mercury lamp, the film is further cured by heating at 160 ° C. for 60 minutes to form a cured film on the substrate. A test substrate on which a cured film was formed was produced.
The cross section of the line pattern with a width of 50 μm of the test substrate was observed using SEM, and the line pattern shape of the photosensitive resin composition was evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1.
(Evaluation criteria)
◯: Good resolution with no line pattern jumping, lifting, and undercutting of a test substrate having a width of 50 μm was confirmed.
X: A line pattern with a width of 50 μm of the test substrate was jumped and lifted, or undercut was confirmed at the bottom of the line.

The details of each component in Table 1 are as follows.
-Omnirad TPO: IGM Resins, 2,4,6-trimethylbenzoylphenyl phosphinate-EPICLON N-770: DIC Corporation, phenol novolac epoxy resin (solid)
EPICLON 850: manufactured by DIC Corporation, bisphenol A type epoxy resin (liquid)
KAYARAD DPHA: Nippon Kayaku Co., Ltd., dipentaerythritol hexa (meth) acrylate Barium sulfate: B-30, Sakai Chemical Industry Co., Ltd. Spherical silica: SO-C2, Admatechs Corporation, DICY: Mitsubishi Chemical Co., Ltd., dicyandiamide / blue pigment: C.I. I. Pigment Blue 15: 3
-Yellow pigment: C.I. I. Pigment Yellow 147

  From Table 1, a carboxyl group-containing resin A having a weight average molecular weight of 1500 or more and less than 5000 and a carboxyl group-containing resin B having a weight average molecular weight of 5000 or more and 150,000 or less are contained in a specific blending ratio, The photosensitive resin composition according to the present invention containing 40 to 300 parts of the inorganic filler in 100 parts of the carboxyl group-containing resin contained in the photosensitive resin composition is excellent in coating property, film forming property, developability and resolution. It turns out that it has sex.

Moreover, about Examples 1-7, developability was further evaluated using the test substrate evaluated by line pattern shape evaluation.
The test substrate surface was observed using a scanning electron microscope (SEM), and the developability of the photosensitive resin composition was evaluated based on the following evaluation criteria. As a result, in all of Examples 1 to 7, in the line pattern of the test substrate having a width of 30 to 100 μm, no residue of the photosensitive resin composition was confirmed between the line patterns, and good developability could be confirmed.

Claims (6)

  A carboxyl group-containing resin A having a weight average molecular weight of 1500 or more and less than 5000, a carboxyl group-containing resin B having a weight average molecular weight of 5000 or more and 150,000 or less, an epoxy resin, a photopolymerization initiator, a photosensitive monomer, , An inorganic filler, and the mixing ratio of the carboxyl group-containing resin A and the carboxyl group-containing resin B is 6: 4 to 3: 7 on a mass basis, and the content of the inorganic filler is 40-300 parts with respect to 100 parts of carboxyl group-containing resin contained in the photosensitive resin composition, The photosensitive resin composition characterized by the above-mentioned.   The photosensitive resin composition of Claim 1 containing an acyl phosphine oxide type photoinitiator as said photoinitiator.   The photosensitive resin composition of Claim 1 or 2 containing at least one of barium sulfate and spherical silica as said inorganic filler.   It has a resin layer obtained by apply | coating the photosensitive resin composition as described in any one of Claims 1-3 to a support film, and drying, The dry film characterized by the above-mentioned.   Hardened | cured material obtained by hardening the photosensitive resin composition as described in any one of Claims 1-3, or the resin layer of the dry film of Claim 4.   A printed wiring board comprising the cured product according to claim 5.