JP2009014990A - Photosensitive resin composition and photosensitive element using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition having excellent alkali developability, capable of forming a cured film excellent in flame retardancy, and capable of suppressing warpage of a substrate and increase of repulsive force when a cured film is formed on the substrate. <P>SOLUTION: The photosensitive resin composition contains (A) a novolac-type acid-modified vinyl group-containing epoxy resin having a biphenyl skeleton, (B) a photopolymerizable compound having a urethane bond and an ethylenically unsaturated group within a molecule, (C) a phosphorus-containing compound, and (D) a photopolymerization initiator. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a photosensitive resin composition and a photosensitive element.

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

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

  Therefore, in order to achieve high resolution of the resist pattern, the photoresist method has been actively used. In this photoresist method, a photosensitive resin composition layer made of a photosensitive resin composition is formed on a substrate, the photosensitive resin composition layer is cured by exposure of a predetermined pattern, and unexposed portions are removed by development. Thus, a cured film having a predetermined pattern is formed.

In addition, the photosensitive resin composition used in such a method is mainly an alkali development type that can be developed with a dilute aqueous alkali solution such as an aqueous sodium carbonate solution from the viewpoint of conservation of the working environment and global environment. . As such a photosensitive resin composition, for example, a liquid resist ink composition described in Patent Document 1 below and a photosensitive thermosetting resin composition described in Patent Document 2 below are known.
JP-A 61-243869 Japanese Patent Laid-Open No. 01-141904

  By the way, in recent years, regulations on flame retardancy of various industrial products against fire have become stricter, and materials used for printed wiring boards and the like are no exception. As a flame retardant method, a method of adding a halogen compound, an antimony compound, a phosphorus compound, a boron compound, an inorganic filler or the like to a material is generally known.

  However, recently, with increasing interest in environmental issues and human safety issues, the focus has shifted to non-polluting, low toxic and safety, not only flammable but also harmful gases and fuming substances. Reduction is being demanded. In response, flame retardant substrates that do not use halogen compounds or antimony compounds have already been developed and put into practical use.

  However, when a cured film is formed on a flame retardant substrate as described above using a conventional photosensitive resin composition as described in Patent Documents 1 and 2, sufficient flame retardancy (preferably, (UL94 VTM-0 level) cannot be ensured by examination by the present inventors.

  In addition, along with recent downsizing and thinning of electronic devices, there is an increasing demand for reduction of the warping and repulsion of the board when mounting components together with the flame retardant technology, such as when a flexible board is used as the board.

  The present invention has been made in view of the above circumstances, has an excellent alkali developability, can form a cured film excellent in flame retardancy, and is formed when a cured film is formed on a substrate. It aims at providing the photosensitive resin composition which can fully suppress generation | occurrence | production of the curvature of a board | substrate, and the increase in a repulsive force. Moreover, an object of this invention is to provide the photosensitive element provided with the photosensitive resin composition layer which consists of such a photosensitive resin composition.

  As a result of intensive studies to achieve the above object, the present inventors have made the photosensitive resin composition contain a resin having a specific structure, a specific photopolymerizable compound, and a phosphorus-containing compound. The inventors have found that the above object can be achieved and have completed the present invention.

  That is, the present invention comprises (A) a novolak acid-modified vinyl group-containing epoxy resin having a biphenyl skeleton, (B) a photopolymerizable compound having a urethane bond and an ethylenically unsaturated group in the molecule, and (C) phosphorus. There is provided a photosensitive resin composition comprising a containing compound and (D) a photopolymerization initiator.

  The photosensitive resin composition of the present invention contains the components (A) to (D), so that development with a dilute alkaline aqueous solution is possible, and a cured film obtained by curing the photosensitive resin composition. The flame retardancy of the substrate can be satisfied at a high level, and the occurrence of warpage of the substrate and the increase in the repulsive force when a cured film is formed on the substrate can be sufficiently suppressed. Therefore, according to the photosensitive resin composition of the present invention, it is possible to efficiently form a cured film having excellent flame retardancy with high resolution, and a cured film comprising the photosensitive resin composition can be formed. Even when formed on a substrate such as a flexible substrate, it is possible to suppress warping of the substrate during component mounting and to keep the repulsive force low.

  Moreover, according to the photosensitive resin composition of the present invention, since the flame retardancy of the cured film can be made sufficiently high without containing a halogen compound or an antimony compound, for example, the environment of a printed wiring board. It becomes possible to reduce load and toxicity. In particular, when the photosensitive resin composition of the present invention is applied to a non-halogen-based or non-antimony-based flame retardant substrate, the above-described effects are more effectively exhibited.

  In the photosensitive resin composition of the present invention, the photopolymerizable compound (B) has a urethane bond derived from the reaction between the terminal hydroxyl group of the polycarbonate compound and / or the polyester compound and the isocyanate group of the diisocyanate compound. In addition, it is preferable to include a compound obtained by reacting a urethane compound having an isocyanate group at a plurality of ends with a compound having a hydroxyl group and an ethylenically unsaturated group. By using the photopolymerizable compound (B) thus obtained, the flexibility of the cured film made of the photosensitive resin composition can be further improved, and the warpage of the substrate when the cured film is formed on the substrate can be improved. Increase in generation and repulsion can be more sufficiently suppressed.

Moreover, in the photosensitive resin composition of this invention, the said (B) photopolymerizable compound has a repeating unit represented by following formula (1) and following formula (2), and is represented by following formula (1). The urethane / unsaturated organooligomer having a molar ratio {(1) / (2)} of 9/1 to 1/9 of the repeating unit represented by the following formula (2) Further, an unsaturated organooxycarbonylimide group is bonded to the end of a urethane oligomer having a number average molecular weight of 1000 to 10,000, which is formed by connecting a copolycarbonate having a hydroxyl group with a number average molecular weight of 600 to 1000 and an organic isocyanate in a chain. The urethane / unsaturated organooligomer is preferably contained.

  By containing the urethane / unsaturated organooligomer, the photosensitive resin composition can obtain a more excellent alkali developability, and can form a cured film having better flame retardancy, and on the substrate. The generation of the warp of the substrate and the increase in the repulsive force when the cured film is formed can be more sufficiently suppressed.

［式（３）中、Ｒ^１及びＲ^２は各々独立に、水素原子、炭素数１〜８のアルキル基、又は、アリール基を示し、ｎは０〜５０の整数を示す。なお、式（３）中、複数存在するＲ^１及びＲ^２はそれぞれ同一でも異なっていてもよい。］ In the photosensitive resin composition of the present invention, the (A) epoxy resin includes (a) an epoxy resin represented by the following general formula (3), (b) an unsaturated group-containing monocarboxylic acid, ( c) It preferably contains an acid-modified vinyl group-containing epoxy resin which is a reaction product with a polybasic carboxylic acid anhydride.

Wherein (3), ^{R 1} and ^{R 2} each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or represents an aryl radical, n is an integer of 0 to 50. In the formula (3), R ¹ and R ² existing in plural numbers may be the same as or different from each other. ]

  (A) By including the above-mentioned specific acid-modified vinyl group-containing epoxy resin as an epoxy resin, the photosensitive resin composition provides excellent alkali developability and forms a cured film having more excellent flame retardancy. It becomes possible.

［式（４）中、Ａ及びＢは各々独立に、直鎖状又は分枝状の炭素数１〜６のアルキル基、又は、アリール基を示し、ＭはＭｇ、Ｃａ、Ａｌ、Ｓｂ、Ｓｎ、Ｇｅ、Ｔｉ、Ｚｎ、Ｆｅ、Ｚｒ、Ｃｅ、Ｂｉ、Ｓｒ、Ｍｎ、Ｌｉ、Ｎａ及びＫからなる群より選択される少なくとも一種の金属を示し、ｍは１〜４の整数を示す。］ Moreover, in the photosensitive resin composition of this invention, it is preferable that the said (C) phosphorus containing compound contains the phosphinic acid salt represented by following General formula (4).

[In Formula (4), A and B each independently represent a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group, and M represents Mg, Ca, Al, Sb, Sn. , Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, and K. m represents an integer of 1 to 4. ]

  When the photosensitive resin composition contains the phosphinic acid salt represented by the general formula (4), the flame retardancy of the obtained cured film can be further improved. In addition, the phosphinate represented by the general formula (4) has a structure that is difficult to hydrolyze, and can effectively prevent the generation of ionic impurities that reduce electrical insulation, so that the cured film is excellent. It can have insulation reliability.

  Moreover, the photosensitive resin composition of this invention may contain phosphate ester further as said (C) phosphorus containing compound. Thereby, the flame retardance of the cured film can be further improved, and since the phosphate ester functions as a plasticizer, the flexibility of the cured film can be further improved.

  Moreover, it is preferable that the photosensitive resin composition of this invention contains (E) thermosetting agent further. When the photosensitive resin composition contains (E) a thermosetting agent, the photosensitive resin composition is photocured and then further thermoset to further improve the insulation reliability of the resulting cured film. Can do.

  The substrate in which the cured film of the photosensitive resin composition of the present invention is formed on a flexible base material such as polyimide is characterized by excellent flame retardancy, and further features low warpage and low resilience when mounting components. And The photosensitive resin composition of the present invention does not contain a halogen-based compound or an antimony-based compound, and can make the cured film sufficiently high in flame retardancy. For example, it reduces the environmental load and toxicity of a printed wiring board. It becomes possible to do.

  Since the photosensitive resin composition of the present invention can form a cured film having sufficient flame retardancy with high resolution and has sufficient flexibility, it is suitable for forming a permanent mask of a printed wiring board, particularly a flexible printed wiring board. It is preferable to be used. That is, the photosensitive resin composition of the present invention is preferably for forming a cured film that becomes a permanent mask on a flexible substrate.

  The present invention also provides a photosensitive element comprising a support and a photosensitive resin composition layer comprising the above-described photosensitive resin composition of the present invention formed on the support. According to such a photosensitive element, by providing the photosensitive resin composition layer composed of the photosensitive resin composition, an excellent alkali developability can be obtained, and a cured film having excellent flame retardancy can be formed. In addition, it is possible to sufficiently suppress the occurrence of warping of the substrate and the increase in the repulsive force when a cured film is formed on the substrate.

  Further, according to the photosensitive element of the present invention, since it has sufficient flame retardancy without using a halogen-based compound or an antimony-based compound, it is possible to efficiently produce a printed wiring board with low environmental load, low toxicity, and high resolution. Production becomes possible.

  According to the present invention, it is possible to form a cured film having excellent alkali developability and excellent flame retardancy, and generation of warpage and repulsive force of the substrate when the cured film is formed on the substrate. The photosensitive resin composition which can fully suppress an increase, and the photosensitive element using the same can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as the case may be. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted. Moreover, in this specification, (meth) acrylic acid means acrylic acid and methacrylic acid corresponding to it, (meth) acrylate means acrylate and its corresponding methacrylate, and (meth) acrylic monomer means acrylic. It means a monomer and the corresponding methacrylic monomer. Moreover, the (meth) acryloyl group in this specification means an acryloyl group and the methacryloyl group corresponding to it, and a (meth) acryloxy group means an acryloxy group and the methacryloxy group corresponding to it.

(Photosensitive resin composition)
The photosensitive resin composition of the present embodiment includes (A) a novolak acid-modified vinyl group-containing epoxy resin having a biphenyl skeleton (hereinafter, sometimes referred to as “component (A)”), and (B) urethane in the molecule. A photopolymerizable compound having a bond and an ethylenically unsaturated group (hereinafter sometimes referred to as “component (B)”), and (C) a phosphorus-containing compound (hereinafter sometimes referred to as “component (C)”). And (D) a photopolymerization initiator (hereinafter referred to as “component (D)” in some cases) as an essential component. Hereinafter, each component contained in the photosensitive resin composition of this embodiment is demonstrated.

<(A) component>
The component (A) is a novolac acid-modified vinyl group-containing epoxy resin having a biphenyl skeleton that is soluble in a dilute alkaline aqueous solution. Among such components (A), (a) an epoxy resin represented by the general formula (3), (b) an unsaturated group-containing monocarboxylic acid, (c) a polybasic carboxylic acid anhydride, Those obtained as reaction products are preferred.

  By incorporating the component (A) synthesized using the epoxy resin having the structure represented by the general formula (3) into the photosensitive resin composition, a photosensitive resin composition excellent in alkali developability can be obtained. it can.

  (B) Specific examples of unsaturated bond-containing monocarboxylic acid include acrylic acid, dimer of acrylic acid, methacrylic acid, β-styrylacrylic acid, β-furfurylacrylic acid, crotonic acid, α-cyanocinnamic acid , Cinnamic acid, half-esters which are a reaction product of a saturated or unsaturated dibasic acid anhydride and a (meth) acrylate derivative having one hydroxyl group in one molecule, and a saturated or unsaturated dibasic acid and unsaturated The half ester which is a reaction material with a group containing monoglycidyl compound is mentioned.

  Examples of half esters include succinic anhydride, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, itaconic anhydride, methylendomethylene. Saturated or unsaturated dibasic anhydrides such as tetrahydrophthalic anhydride, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, glycerin di (meta ) Acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, (meth) acrylate of phenylglycidyl ether Compounds obtained by reacting equimolar amounts of (meth) acrylate derivatives having one hydroxyl group in one molecule such as a rate, or saturated or unsaturated dibasic acids (for example, succinic acid, maleic acid, adipine Acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, itaconic acid, fumaric acid, etc.) and an unsaturated group-containing monoglycidyl compound (eg, glycidyl (meth) acrylate, etc.) in an equimolar ratio. And the like.

  (B) Unsaturated bond-containing morphanobonic acid exemplified as described above can be used alone or in combination of two or more. Among these, acrylic acid is preferable from the viewpoint of developability.

  Specific examples of (c) polybasic carboxylic acid anhydrides include maleic anhydride, succinic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride and the like.

  The acid value of the component (A) is preferably 60 to 150 mgKOH / g, and more preferably 80 to 120 mgKOH / g. If the acid value is less than 60 mgKOH / g, the alkali developability tends to be impaired, and if it exceeds 150 mgKOH / g, the insulation reliability, chemical resistance and plating resistance of the resulting cured film tend to be insufficient.

In addition, the acid value of (A) component can be measured with the following method. First, about 1 g of the resin solution as the component (A) is precisely weighed, 30 g of acetone is added to the resin solution, and the resin solution is uniformly dissolved. Next, an appropriate amount of phenolphthalein as an indicator is added to the solution, and titration is performed using a 0.1N aqueous KOH solution. And from the titration result, the following formula (I);
A = 10 × Vf × 56.1 / (Wp × Y) (I)
To calculate the acid value. In the above formula (I), A represents the acid value (mgKOH / g), Vf represents the titration amount (mL) of phenolphthalein, and Wp represents the mass (g) of the resin solution as the component (A). Y represents the proportion (% by mass) of the nonvolatile content of the resin solution as the component (A).

  The novolak-type acid-modified vinyl group-containing epoxy resin as the component (A) can be obtained by purchasing a commercially available product. Specific examples include ZCR-1569H, ZCR-1596H, ZCR-1611H, and ZCR-1610H (all manufactured by Nippon Kayaku Co., Ltd., trade names).

<(B) component>
The component (B) is a photopolymerizable compound having a urethane bond and an ethylenically unsaturated group in the molecule. The component (B) includes a urethane compound having a urethane bond derived from a reaction between a hydroxyl group at a terminal of a polycarbonate compound and / or a polyester compound and an isocyanate group of a diisocyanate compound and having an isocyanate group at a plurality of terminals; It is preferable to include a compound obtained by reacting a group and a compound having an ethylenically unsaturated group. In addition, in order to obtain (B) component, it is preferable to use the urethane compound obtained by making a polycarbonate compound and diisocyanate react from a viewpoint which makes the external appearance of a cured film favorable.

  Examples of the polycarbonate compound used in the above reaction include those having a structure in which an alkylene group is arranged in the main chain through a carbonate bond. Such a polycarbonate compound can be obtained by a known method. For example, when a polycarbonate compound is obtained by the phosgene method, a diol compound and phosgene are reacted. Examples of the diol compound include diethylene glycol, triethylene glycol, tetraethylene glycol, tripropylene glycol, polypropylene glycol, erylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 2 -Methyl-1,3-butanediol, neopentyl glycol, 2-methylpentanediol, 3-methylpentanediol, 2,2,4-trimethyl-1,6-hexanediol, 3,3,5-trimethyl-1 , 6-hexanediol, 2,3,5-trimethyl-pentanediol, 1,6-hexanediol, 1,5-pentanediol and the like. These can be used individually by 1 type or in combination of 2 or more types. Further, polyol compounds such as trimethylolpropane, trimethylolethane, hexanetriol, heptanetriol, pentaerythritol may be contained.

Among the polycarbonate compounds, hexamethylene carbonate represented by the following general formula (5) derived from 1,6-hexanediol and 1,5-pentanediol and pentamethylene carbonate represented by the following general formula (6) The thing containing is preferable.
— (CH ₂ ) ₆ —O—CO—O— (5)
_{- (CH 2) 5 -O-} CO-O- (6)

  The molar ratio of hexamethylene carbonate and pentamethylene carbonate contained in the polycarbonate compound is preferably hexamethylene carbonate / pentamethylene carbonate = 1/9 to 9/1. If the content ratio is outside the above range, the elongation and strength of the cured film tend to decrease.

  The polyester compound used in the above reaction can be obtained by a known method by polycondensation of a polybasic acid and a polyhydric alcohol. Examples of the polybasic acid include aromatic and aliphatic dicarboxylic acids such as terephthalic acid, isophthalic acid, adipic acid, and sebacic acid. Examples of the polyhydric alcohol include glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, hexanediol, neopentyl glycol, diethylene glycol, and triethylene glycol.

  The polycarbonate compound and the polyester compound preferably have a weight average molecular weight (for example, measured by GPC and converted to polystyrene) of 600 to 1,000. When the weight average molecular weight is outside the above range, the elongation and strength of the cured film tend to decrease.

  Examples of the diisocyanate compound used in the above reaction include an aliphatic diisocyanate compound having a divalent aliphatic group such as an alkylene group, an alicyclic diisocyanate compound having a divalent alicyclic group such as cycloalkylene, and an aromatic group. Group diisocyanate compounds, and isocyanurate-modified products, carbodiimidization-modified products, and biuret-modified products.

  Examples of the aliphatic diisocyanate compound include hexamethylene diisocyanate and trimethylhexamethylene diisocyanate. Examples of the alicyclic diisocyanate compound include isophorone diisocyanate, methylene bis (cyclohexyl) diisocyanate, and 1,3- or 1,4-bis (isocyanate methyl) cyclohexane. As aromatic diisocyanate compounds, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,4-triene diisocyanate or dimerized polymer of 2,6-triene diisocyanate, (o, p or m) -xylene diisocyanate , Diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate. These can be used individually by 1 type or in combination of 2 or more types. Moreover, the isocyanate compound which has 2 or more isocyanate groups, such as a triphenylmethane triisocyanate and a tris (isocyanate phenyl) thiophosphate, may be contained. Among these, alicyclic diisocyanate compounds are preferable and isophorone diisocyanate is more preferable from the viewpoint of achieving a higher level of flexibility and toughness of the cured film.

  By reacting the above-described polycarbonate compound and / or polyester compound with a diisocyanate compound, a urethane compound having a urethane bond and having an isocyanate group at a plurality of terminals can be obtained. The urethane compound has isocyanate groups at both ends, and in the above reaction, the compounding amount of the diisocyanate compound may be 1.01 to 2.0 mol with respect to 1 mol of the total amount of the polycarbonate compound and the polyester compound. Preferably, it is 1.1-2.0. When the compounding amount of the diisocyanate compound is less than 1.01 mol or exceeds 2.0 mol, there is a tendency that a urethane compound having isocyanate groups at both ends cannot be obtained stably. In the reaction for synthesizing the urethane compound, it is preferable to add dibutyltin dilaurate as a catalyst. The reaction temperature is preferably 60 to 120 ° C. When the temperature is lower than 60 ° C., the reaction tends not to proceed sufficiently. When the temperature exceeds 120 ° C., the operation tends to be dangerous due to sudden heat generation.

  By reacting the urethane compound with a compound having a hydroxyl group and an ethylenically unsaturated group in the molecule, the component (B) can be obtained. Examples of the compound having a hydroxyl group and an ethylenically unsaturated group in the molecule include compounds having a hydroxyl group and a (meth) acryloyl group in the molecule. Examples of such compounds include hydroxy (meth) acrylates, caprolactone adducts or alkylene oxide adducts thereof, ester compounds of polyhydric alcohols such as glycerin and (meth) acrylic acid, and glycidyl (meth) arylate acrylic acid. Addenda may be mentioned.

  The component (B) has a molar ratio of the repeating unit represented by the above formula (1) and the repeating unit represented by the above formula (2) of {formula (1) / formula (2)} of 9 1/1/9 urethane / unsaturated organooligomer, which has a hydroxyl group-terminated copolycarbonate (number average molecular weight: 600 to 1,000) and an organic isocyanate linked in a chain It is more preferable to contain a urethane / unsaturated organooligomer in which an unsaturated organooxycarbonylimide group is further bonded to the end of the urethane oligomer (number average molecular weight: 1,000 to 10,000).

  Examples of the unsaturated organooxycarbonylimide group include a group represented by the following general formula (7).

［式中、Ｒ^３＝Ｒ^４−基は、二重結合を１つ以上含む不飽和オルガノ基を示す。］

[Wherein R ³ = R ⁴ -represents an unsaturated organo group containing one or more double bonds. ]

The R ³ ═R ⁴ — group in the general formula (7) is an unsaturated organo group containing one or more double bonds. The two R ³ and R ⁴ basic skeletons sandwiching the double bond may be the same or different from each other.

Examples of such an unsaturated organo group (R ³ = R ⁴ -group) include a dimethylene acrylate group (-C ₂ H ₄ OCOCH = CH ₂ ) derived from hydroxyethyl acrylate and a tripropylene derived from hydroxypropylene acrylate. Methylene acrylate group, tetramethylene acrylate group derived from hydroxybutyl acrylate, pentamethylenecarbonyloxydimethylene-acrylate group derived from hydroxyethylene acrylate / caprolactone adduct {— (CH ₂ ) ₅ COOC ₂ H ₄ OCOCH═CH ₂ } Pentamethylenecarbonyloxytrimethylene-acrylate group derived from hydroxypropyl acrylate / caprolactone adduct, pen derived from hydroxybutyl acrylate / caprolactone adduct Methylene carbonyl oxytetramethylene - acrylate group, caprolactone adduct or a group derived from alkylene oxide adduct, di methyleneoxy dimethylene from hydroxyethylene acrylate ethylene oxide adduct - acrylate group (-C ₂ H ₄ OC ₂ H ₄ OCOCH = CH ₂ ), methyldimethyleneoxydimethylene-acrylate group derived from hydroxyethylene acrylate / propylene oxide adduct {—C ₂ H ₃ (CH ₃ ) OC ₂ H ₄ OCOCH═CH ₂ }, hydroxyethyl acrylate ethyl derived from butylene oxide adduct di methyleneoxy dimethylene - acrylate group _{{-C 2 H 3 (C 2} H 5) OC 2 H 4 OCOCH = CH 2)} , and the like.

  Examples of the urethane / unsaturated organooligomer in which the unsaturated organooxycarbonylimide group represented by the general formula (7) is bonded to both ends of the urethane oligomer include the compound of the following general formula (8).

［式中、Ｒ^３＝Ｒ^４−基は二重結合を１つ以上含む不飽和オルガノ基を示し、Ｒ^５はコポリカーボネ−トの両末端からヒドロキシル基が脱離した２価の残基を示し、Ｒ^６は有機イソシアネ−トからイソシアネ−ト基が脱離した２価の脂肪族基又は芳香族基を示し、ｕは１〜２００の整数を示す。なお、式中、複数存在するＲ^３、Ｒ^４、Ｒ^５及びＲ^６は、それぞれ同一でも異なっていてもよい。］

[Wherein R ³ = R ⁴ -group represents an unsaturated organo group containing one or more double bonds, and R ⁵ represents a divalent residue in which hydroxyl groups are eliminated from both ends of the copolycarbonate. R ⁶ represents a divalent aliphatic group or aromatic group in which the isocyanate group is eliminated from the organic isocyanate, and u represents an integer of 1 to 200. In the formula, a plurality of R ³ , R ⁴ , R ⁵ and R ⁶ may be the same or different. ]

U in the general formula (8) is the number of repeating units in the urethane / unsaturated organooligomer, and u is preferably from 1 to 100, more preferably from 1 to 10. The R ³ ═R ⁴ — group in the general formula (8) is an unsaturated organo group containing one or more double bonds, and an oxy group is present at both ends of the urethane oligomer composed of R ⁵ and R ^6. They are bonded via a carbonylimide group (—OCONH—).

  The number average molecular weight of the urethane oligomer is preferably 1,000 to 10,000. When the number average molecular weight of the urethane oligomer is less than 1,000, the flexibility of the cured film tends to decrease, and when it exceeds 10,000, the developability of the photosensitive resin composition tends to decrease.

R ^{5 in the} general formula (8) is a divalent residue in which hydroxyl groups are eliminated from both ends of the copolycarbonate. The number average molecular weight of the copolycarbonate is preferably 600 to 1,000. When the number average molecular weight of the copolycarbonate is less than 600, the plasticity of the thermosetting resin composition tends to decrease, and when it exceeds 1,000, the developability, sensitivity, etc. tend to decrease.

R ^{5 in the} general formula (8) is a repeating unit derived from the hexamethylene carbonate represented by the formula (1) and a pentamethylene carbonate represented by the formula (2). A copolymer group containing a derived repeating unit is preferable. Adjacent repeating units may be the same or different. Further, the arrangement of the repeating units may be regular or irregular. Examples of R ⁵ include a divalent residue represented by the following formula (9).

［式中ｒ、ｓは、各々独立に１以上の整数を示す。］

[Wherein, r and s each independently represent an integer of 1 or more. ]

Molar ratio {formula (1) / formula (2)} of the repeating unit represented by the above formula (1) and the repeating unit represented by the above formula (2) in R ⁵ of the general formula (8), The ratio of the number of moles of the repeating unit represented by the above formula (1) to the number of moles of the repeating unit represented by the above formula (2) is preferably 9/1 to 1/9, 7.5 More preferably, the ratio is /2.5 to 1.5 / 8.5. In particular, when R ⁵ is a copolymer consisting only of a repeating unit represented by the above formula (1) and a repeating unit represented by the above formula (2), as represented by the above formula (9), If the molar ratio {formula (1) / formula (2)}, that is, the ratio of r to s (r / s) is in the range of 7.5 / 2.5 to 1.5 / 8.5, urethane Unsaturated organooligomer is effectively amorphized and can effectively prevent gelation of urethane / unsaturated organooligomer.

R ^{5 in the} general formula (8) may be a copolymer composed only of the repeating unit represented by the above formula (1) and the repeating unit represented by the above formula (2). It is preferable that the repeating unit in the coalescence includes a residue (polyol residue) from which hydroxyl groups at both ends of the polyol are eliminated. If a polyol residue is contained, the molar ratio {formula (1) / formula (2)} of the repeat unit represented by the above formula (1) and the repeat unit represented by the above formula (2) is: Effective prevention of gelation of urethane / unsaturated organooligomers if within the range of 9/1 to 1/9 even outside the range of 7.5 / 2.5 to 1.5 / 8.5 can do.

Examples of the polyol residue include 1,4-butadiol residue {— (CH ₂ ) ₄ —}, trimethylolpropane residue {—CH ₂ C (CH ₂ OH) (C ₂ H ₅ ) CH ₂ — }, Trimethylolethane residue {—CH ₂ C (CH ₂ OH) (CH ₃ ) CH ₂ —}, hexanetriol residue [eg, {— (CH ₂ ) ₄ CH (OH) CH ₂ —}, etc.] , heptane triol residues _{[e.g., {(- CH 2) 5} CH (OH) CH 2 -} , etc.], pentaerythritol residue _{{-CH 2 C (CH 2 OH} ) 2 CH 2 -} multifunctional polyols such as Residue.

When the polyol residue is 1,4 butadiol residue, the proportion of the polyol residue contained in R ⁵ of the general formula (8) is the repeating unit represented by the above formula (1) and the above formula (2). It is preferable that it is 1-20 mol% on the basis of the total mole number with the repeating unit represented, and it is more preferable that it is 5-15 mol%. In the case of a polyol residue other than 1,4 butadiol residue, the proportion of the polyol residue contained in R ⁵ is the repeating unit represented by the above formula (1) and the repeating unit represented by the above formula (2). It is preferably 1 to 10 mol% based on the total number of moles with the unit.

Specific examples of the divalent aliphatic group or aromatic group represented by R ⁶ in the general formula (8) include toluene-2,4-diyl group, toluene-2,6-diyl group, isophorone diisocyanate. 1-methylene-1,3,3-trimethylcyclohexane-5-yl group, (o, m or p) -xylenediyl group {— (CH ₃ ) ₂ C ₆ H ₂ —}, methylenebis (cyclohexenyl) group _{(-C 6 H 10 CH 2 C} 6 H 10 -), trimethyl hexamethylene group _{{- (CH 3) 3 C} 6 H 9 -}, cyclohexane-1,4-dimethylene group, a naphthalene -1 , 5-diyl group, triphenylene thiophosphate group {(—C ₆ H ₄ ) ₃ P═S} derived from tris (isocyanatophenyl) thiophosphate.

R ⁵ and R ^{6 in} the general formula (8) are urethane-bonded to form a urethane oligomer. In the main chain containing R ⁵ and R ⁶ , if residues such as water, low molecular polyol, polyamine and the like are contained by an ether bond or an imino bond within a range not impairing the effects of the present invention, The chain length is preferably increased as appropriate. Examples of the residue used for extension of the main chain include a residue from which hydrogen in the hydroxyl group of each compound such as polyester polyol, polyether polyol, polycarbonate polyol, and polyolefin polyol is eliminated. It is done.

  Examples of commercially available urethane / unsaturated organooligomers include UF-8001, UF-8002, UF-8003, and UF-8003M (all are trade names manufactured by Kyoeisha Chemical Co., Ltd.).

<(C) component>
(C) A component is a phosphorus containing compound. It is preferable that (C) component contains the (C1) phosphinic acid salt shown by the said General formula (4).

  Specific examples of A and B in the general formula (4) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tertiary butyl group, an n-pentyl group, and a phenyl group. It is done. Such (C1) phosphinic acid salts can be used singly or in combination of two or more.

  In addition, 80% by mass or more of the total of (C1) phosphinate contained in the photosensitive resin composition has a particle size of 10 μm from the viewpoint of improving adhesion reliability when used in the photosensitive resin composition and the photosensitive element. Or less, more preferably 5 μm or less, and even more preferably 3 μm or less. When the particle diameter exceeds 10 μm, the appearance of the coating film of the photosensitive resin composition tends to deteriorate, and the production of a high-resolution printed wiring board tends to be difficult.

  (C1) Commercially available phosphinates are available, and examples include EXOLIT OP 930, EXOLIT OP 935, and EXOLIT OP 940 (all are trade names manufactured by Clariant).

  In order to further improve the flame retardancy and flexibility of the cured film, the photosensitive resin composition can also contain (C2) phosphate ester in addition to (C1) phosphinate. Specific examples of (C2) phosphate ester include, for example, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, 1,3-dihydroxybenzene / trichlorophosphine polycondensation And phenol condensates of 2,2-bis (p-hydroxyphenyl) propane / trichlorophosphine oxide polycondensate. These are commercially available, for example, TPP, TCP, TXP, CDP, XDP, CR-733S, CR-741, and CR-747 (all are trade names, manufactured by Daihachi Chemical Co., Ltd.), and PFR , FP-600 and FP-700 (both manufactured by Adeka, trade names).

<(D) component>
Examples of the photopolymerization initiator (D) include benzophenone, 4,4′-bis (dimethylamino) benzophenone (Michler ketone), 4,4′-bis (diethylamino) benzophenone, 4-methoxy-4′- Dimethylaminobenzophenone, 2-benzyl-2-dimethylamino- (1-morpholinophenone) -butanone-1,2-ethylanthraquinone, aromatic ketones such as phenanthrenequinone, quinones such as alkylanthraquinone, benzoin methyl ether, benzoin ethyl Ether, benzoin ether such as benzoin phenyl ether, benzoin such as methyl benzoin and ethyl benzoin, benzyl derivatives such as benzyldimethyl ketal, 9-phenylacridine, 1,7-bis (9,9′-acridinyl) heptane, etc. Examples include acridine derivatives, N-phenylglycine, N-phenylglycine derivatives, and coumarin compounds. These can be used individually by 1 type or in combination of 2 or more types.

  The content of the component (A) in the photosensitive resin composition is based on the total solid content of the photosensitive resin composition from the viewpoint of improving the flame retardancy of the resulting cured film and reducing warpage and repulsion. It is preferable that it is 35-70 mass%, and it is more preferable that it is 40-65 mass%. When the component (A) is less than 35% by mass, the flame retardancy tends to decrease, and when it exceeds 70% by mass, development with a dilute aqueous alkali solution tends to be difficult.

  The content of the component (B) in the photosensitive resin composition is preferably 1 to 15% by mass, more preferably 2 to 10% by mass, based on the total solid content of the photosensitive resin composition. preferable. When the component (B) exceeds 15% by mass, flame retardancy tends to decrease, and when it is less than 1% by mass, warpage and resilience when mounted on a substrate or the like tend to increase.

  The content of the component (C) in the photosensitive resin composition is preferably 7 to 30% by mass, more preferably 10 to 25% by mass, based on the total solid content of the photosensitive resin composition. preferable. When the content of the component (C) is less than 7% by mass, the resolution tends to be impaired, and when it exceeds 30% by mass, the flame retardancy tends to decrease.

  In addition, it is preferable that the content of the (C) component in the photosensitive resin composition in terms of phosphorus is 1.5 to 5.0% by mass based on the total solid content of the photosensitive resin composition. It is more preferable that it is 0.0-4.5 mass%. If the content of the component (C) in terms of phosphorus is less than 1.5% by mass, the flame retardancy tends to decrease, and if it exceeds 5.0% by mass, the bending resistance of the cured film tends to decrease. is there.

  The content of the component (D) in the photosensitive resin composition is preferably 0.1 to 10% by mass, based on the total solid content of the photosensitive resin composition, from the viewpoint of photosensitivity, It is more preferable that it is 2-5 mass%.

  The photosensitive resin composition of the present embodiment further contains (E) a thermosetting agent (hereinafter sometimes referred to as “(E) component”) in addition to the components (A) to (D) described above. Is preferred. Hereinafter, the component (E) will be described.

<(E) component>
Specific examples of the thermosetting agent as component (E) include thermosetting compounds such as epoxy resins, phenol resins, urea resins, and melamine resins. Examples of the epoxy resin include bisphenol A type tertiary fatty acid modified polyol epoxy resin; diglycidyl esters such as diglycidyl phthalate and diglycidyl tetrahydrophthalate, and diglycidyl amines such as diglycidyl aniline and diglycidyl toluidine. Etc. These can be used alone or in combination of two or more.

  Moreover, the block isocyanate compound which is a latent thermosetting agent can also be used as (E) component. Examples of the blocked isocyanate compound include polyisocyanate compounds blocked with a blocking agent such as an alcohol compound, a phenol compound, ε-caprolactam, an oxime compound, and an active methylene compound. Examples of blocked polyisocyanate compounds include 4,4-diphenylmethane disissocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene 1,5-diisocyanate, o-xylene diisocyanate, and m-xylene. Aromatic polyisocyanates such as diisocyanates and 2,4-tolylene dimers, aliphatic polyisocyanates such as hexamethylene diisocyanate, 4,4-methylenebis (cyclohexyl isocyanate) and isophorone diisocyanate, and alicyclic polyisocyanates such as bicycloheptane triisocyanate Is mentioned. Among these, aromatic polyisocyanates are preferable from the viewpoint of heat resistance, and aliphatic polyisocyanates or alicyclic polyisocyanates are preferable from the viewpoint of preventing coloring.

  When the photosensitive resin composition contains the component (E), the content is 5 to 20 on the basis of the total solid content of the photosensitive resin composition from the viewpoint of obtaining excellent flame retardancy and insulation reliability. It is preferable that it is mass%, and it is more preferable that it is 8-15 mass%.

  In addition, the photosensitive resin composition of this embodiment may contain other photopolymerizable compounds other than (B) component. Specific examples of other photopolymerizable compounds include bisphenol A (meth) acrylate compounds; compounds obtained by reacting polyhydric alcohols with α, β-unsaturated carboxylic acids; glycidyl group-containing compounds with α, β- Compounds obtained by reacting an unsaturated carboxylic acid; urethane monomers or urethane oligomers such as (meth) acrylate compounds having a urethane bond. Besides these, nonylphenoxypolyoxyethylene acrylate; γ-chloro-β-hydroxypropyl-β ′-(meth) acryloyloxyethyl-o-phthalate, β-hydroxyalkyl-β ′-(meth) acryloyloxy Examples thereof include phthalic acid compounds such as alkyl-o-phthalate; (meth) acrylic acid alkyl ester, EO-modified nonylphenyl (meth) acrylate, and the like. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of bisphenol A-based (meth) acrylate compounds include 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxypolypropoxy). ) Phenyl) propane, 2,2-bis (4-((meth) acryloxypolybutoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane, etc. Can be mentioned.

  Examples of 2,2-bis (4-((meth) acryloxypolyethoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxy) phenyl) propane, 2,2- Bis (4-((meth) acryloxytriethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetraethoxy) phenyl) propane, 2,2-bis (4-((meth)) Acryloxypentaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptaethoxy) phenyl) propane 2,2-bis (4-((meth) acryloxyoctaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxy nonaethoxy) ) Phenyl) propane, 2,2-bis (4-((meth) acryloxydecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyundecaethoxy) phenyl) propane, 2, 2-bis (4-((meth) acryloxydodecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytridecaethoxy) phenyl) propane, 2,2-bis (4- ( (Meth) acryloxytetradecaethoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecaethoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxyhexa) Decaethoxy) phenyl) propane and the like. These can be used individually by 1 type or in combination of 2 or more types.

  Among these, 2,2-bis (4- (methacryloxypentaethoxy) phenyl) propane is commercially available as BPE-500 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.). (4- (Methacryloxypentadecaethoxy) phenyl) propane is commercially available as BPE-1300 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.).

  Examples of 2,2-bis (4-((meth) acryloxypolypropoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydipropoxy) phenyl) propane, 2,2- Bis (4-((meth) acryloxytripropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytetrapropoxy) phenyl) propane, 2,2-bis (4-((meth)) Acryloxypentapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyhexapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyheptapropoxy) phenyl) propane 2,2-bis (4-((meth) acryloxyoctapropoxy) phenyl) propane, 2,2-bis (4-((meth) acrylic) Xinonapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxydecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxyundecapropoxy) phenyl) propane 2,2-bis (4-((meth) acryloxydodecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxytridecapropoxy) phenyl) propane, 2,2-bis ( 4-((meth) acryloxytetradecapropoxy) phenyl) propane, 2,2-bis (4-((meth) acryloxypentadecapropoxy) phenyl) propane and 2,2-bis (4-((meth)) And acryloxyhexadecapropoxy) phenyl) propane. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of 2,2-bis (4-((meth) acryloxypolyethoxypolypropoxy) phenyl) propane include 2,2-bis (4-((meth) acryloxydiethoxyoctapropoxy) phenyl) propane, Examples include 2,2-bis (4-((meth) acryloxytetraethoxytetrapropoxy) phenyl) propane and 2,2-bis (4-((meth) acryloxyhexaethoxyhexapropoxy) phenyl) propane. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of the compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid include, for example, polyethylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups. Polypropylene glycol di (meth) acrylate, polyethylene polypropylene glycol di (meth) acrylate having 2 to 14 ethylene groups and 2 to 14 propylene groups, trimethylolpropane di (meth) acrylate, tri Methylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, EO / PO-modified trimethylolpropane tri (meth) acrylate, tetramethylolmethanetri (meth) A Examples thereof include acrylate, tetramethylolmethane tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. These can be used individually by 1 type or in combination of 2 or more types.

“EO” refers to “ethylene oxide”, and “PO” refers to “propylene oxide”. Further, “EO-modified” means having a block structure of ethylene oxide units (—CH ₂ CH ₂ O—), and “PO-modified” means propylene oxide units (—CH ₂ CH (CH ₃ ) O. -) Having a block structure.

  Examples of the compound obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid include trimethylolpropane triglycidyl ether tri (meth) acrylate and 2,2-bis (4- (meth) acryloxy- 2-hydroxy-propyloxy) phenyl and the like. These can be used individually by 1 type or in combination of 2 or more types. In addition, (meth) acrylic acid etc. are mentioned as said (alpha), (beta)-unsaturated carboxylic acid.

  Examples of the urethane monomer or urethane oligomer include a (meth) acryl monomer having an OH group at the β-position and a diisocyanate such as isophorone diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, and 1,6-hexamethylene diisocyanate. Addition reaction product with compound, tris ((meth) acryloxytetraethylene glycol isocyanate) hexamethylene isocyanurate, EO modified urethane di (meth) acrylate, EO or PO modified urethane di (meth) acrylate, carboxyl group-containing urethane (meth) acrylate Etc. These can be used individually by 1 type or in combination of 2 or more types.

  Furthermore, examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid butyl ester, and (meth) acrylic acid 2-ethylhexyl ester. It is done. These can be used individually by 1 type or in combination of 2 or more types.

  In addition, the photosensitive resin composition of the present embodiment includes a dye such as malachite green, a photochromic agent such as leuco crystal violet, a plasticizer such as a thermochromic inhibitor or p-toluenesulfonamide, phthalocyanine blue, if necessary. Phthalocyanine-based organic pigments such as azo-based pigments, inorganic pigments such as titanium dioxide, silica, alumina, talc, calcium carbonate or barium sulfate, and other fillers, antifoaming agents, stabilizers, and adhesion-imparting agents , Leveling agents, antioxidants, fragrances, imaging agents, and the like. These components are each preferably contained in an amount of about 0.01 to 20% by mass based on the total solid content of the photosensitive resin composition. Moreover, said component can be used individually by 1 type or in combination of 2 or more types.

  Furthermore, in the photosensitive resin composition of the present embodiment, the above components are mixed with methanol, ethanol, acetone, methyl ethyl ketone, methyl cellosolve, ethyl cellosolve, toluene, N, N-dimethylformamide, propylene glycol monomethyl ether as necessary. Etc. or a mixed solvent thereof, and can be used as a dispersion having a solid content of about 30 to 70% by mass.

  The photosensitive resin composition of the present embodiment as described above is applied as a liquid resist on a metal surface such as copper, a copper-based alloy, iron, and an iron-based alloy, and then dried, if necessary. It can be used by covering a protective film, or in the form of a photosensitive element described later.

(Photosensitive element)
Next, the photosensitive element using the photosensitive resin composition of this embodiment mentioned above is demonstrated.

  FIG. 1 is a schematic cross-sectional view showing a preferred embodiment of the photosensitive element of the present invention. The photosensitive element 1 shown in FIG. 1 includes a support 10 and a photosensitive resin composition layer 14 provided on the support 10. The photosensitive resin composition layer 14 is a layer made of the photosensitive resin composition of the present embodiment described above. Moreover, the photosensitive element 1 of this invention may coat | cover the surface F1 on the opposite side to the contact surface with the support body 10 of the photosensitive resin composition layer 14 with a protective film.

  The photosensitive resin composition layer 14 is obtained by dispersing the photosensitive resin composition of the present embodiment in the above-described solvent or mixed solvent to obtain a dispersion having a solid content of about 30 to 70% by mass, and then supporting the dispersion. Preferably, it is formed by coating on 10.

  Although the thickness of the photosensitive resin composition layer 14 varies depending on the application, it is preferably 10 to 100 μm and more preferably 20 to 60 μm in thickness after drying after removing the solvent by heating and / or hot air blowing. preferable. If this thickness is less than 10 μm, there is a tendency that it is difficult to apply industrially, and if it exceeds 100 μm, the above-mentioned effects produced by the present invention tend to be reduced, in particular, the resolution tends to decrease, and the flexibility tends to decrease. It is in.

  Examples of the support 10 included in the photosensitive element 1 include polymer films having heat resistance and solvent resistance such as polyethylene terephthalate, polypropylene, polyethylene, and polyester.

  The thickness of the support 10 is preferably 5 to 100 μm, and more preferably 10 to 30 μm. If the thickness is less than 5 μm, the support tends to be broken when the support is peeled off before development, and if it exceeds 100 μm, the resolution and flexibility tend to decrease.

  The photosensitive element 1 consisting of two layers of the support 10 and the photosensitive resin composition layer 14 as described above or the photosensitive element consisting of three layers of the support 10, the photosensitive resin composition layer 14 and the protective film is as follows. For example, it may be stored as it is, or it can be wound around a roll core and stored after interposing a protective film.

  The resist pattern forming method using the photosensitive element of the present embodiment includes a removing step of removing the protective film from the photosensitive element as necessary, and the photosensitive resin composition layer 14 facing the circuit forming substrate. Then, the photosensitive element 1 from which the protective film has been removed is laminated on the circuit-forming substrate, and a predetermined part of the photosensitive resin composition layer 14 is irradiated directly or through the support 10 with an actinic ray. And an exposure step of forming a photocured portion on the photosensitive resin composition layer 14 and a developing step of removing the photosensitive resin composition layer 14 other than the photocured portion. In addition, in the case of the photosensitive element in which the protective film is not provided, the said removal process is not performed.

  Here, the circuit forming substrate is an insulating layer and a conductor layer (copper, copper alloy, nickel, chromium, iron, stainless steel or other iron alloy, preferably copper, copper based) formed on the insulating layer. An alloy and an iron-based alloy). This substrate is preferably a flexible substrate.

  Examples of the laminating method in the laminating step after the removing step of removing the protective film as necessary include a method of laminating by pressing the photosensitive resin composition layer on the circuit forming substrate while heating. The atmosphere during the lamination is not particularly limited, but the lamination is preferably performed under reduced pressure from the viewpoint of adhesion and followability. The surface to be laminated is usually the surface of the conductor layer of the circuit forming substrate, but may be a surface other than the conductor layer.

  The heating temperature of the photosensitive resin composition layer is preferably 70 to 130 ° C., the pressure bonding pressure is preferably about 0.1 to 1.0 MPa, and the ambient pressure is more preferably 4000 Pa or less. However, these conditions are not particularly limited. In addition, if the photosensitive resin composition layer is heated to 70 to 130 ° C. as described above, it is not necessary to pre-heat the circuit forming substrate in advance, but in order to further improve the laminating property, Pre-heat treatment of the substrate can also be performed.

  After the lamination is completed in this manner, a photocured portion is formed by irradiating a predetermined portion of the photosensitive resin composition layer with actinic rays in an exposure step. Examples of the method for forming the photocured portion include a method of irradiating an actinic ray in an image form through a negative or positive mask pattern called an artwork. At this time, when the support 10 existing on the photosensitive resin composition layer 14 is transparent, it can be irradiated with actinic rays as it is, but when the support 10 is opaque, the support 10 is removed. After that, the photosensitive resin composition layer 14 is irradiated with actinic rays.

  As the light source of actinic light, a known light source such as a carbon arc lamp, a mercury vapor arc lamp, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, or the like that can effectively emit ultraviolet rays can be used. Moreover, what can radiate | emit visible light effectively, such as a flood bulb for photography, a solar lamp, can be used.

  Next, after the exposure, when a support is present on the photosensitive resin composition layer, after removing the support, in the development process, the photosensitive resin other than the photocured portion by wet development, dry development, etc. The composition layer is removed and developed to form a resist pattern.

  In the case of wet development, development is performed using a developer such as an alkaline aqueous solution by a known method such as spraying, rocking immersion, brushing, or scraping. As the developer, a developer that is safe and stable and has good operability is used. For example, a dilute solution (1 to 5% by mass aqueous solution) of sodium carbonate at 20 to 50 ° C. is used.

  For example, when the resist pattern obtained by the above-described forming method is used as a solder resist for a printed wiring board, a high pressure is used for the purpose of improving solder heat resistance, chemical resistance, etc. as the solder resist after completion of the development process. It is preferable to perform ultraviolet irradiation with a mercury lamp or heating with an oven.

In the case of irradiating ultraviolet rays, the irradiation amount can be adjusted as necessary. For example, the irradiation can be performed at an irradiation amount of about 0.2 to 10 J / cm ² . Moreover, when heating, it is preferable to hold | maintain for about 15 to 90 minutes in the range of about 100-170 degreeC. Moreover, you may implement both ultraviolet irradiation and a heating. In this case, both may be performed at the same time, and after either one is performed, the other may be performed.

  The resist pattern obtained by the above-described forming method is preferably used as a permanent mask formed on a printed wiring board. Since the cured film formed from the photosensitive resin composition of the present embodiment has excellent flame retardancy, it is also effective as a permanent mask for printed wiring boards that also serves as a protective film for wiring after soldering to the substrate. It is.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

(Examples 1-3, Comparative Examples 1-2)
First, each component was mixed at a blending ratio (solid content, mass basis) shown in Table 1 (however, methyl ethyl ketone was a mass basis as a liquid) to obtain a photosensitive resin composition solution.

  In Table 1, component (A) is biphenyl type epoxy acrylate (manufactured by Nippon Kayaku Co., Ltd., trade name: ZCR-1569H, acid value = 98, weight average molecular weight = 4,500).

  The component (B-1) is an 80% by mass methyl ethyl ketone solution of urethane / unsaturated organooligomer having a weight average molecular weight of 5,000 (manufactured by Kyoeisha Chemical Co., Ltd., trade name: UF-8003), and (B-2 The component is a urethane / unsaturated organooligomer having a weight average molecular weight of 4,500 (Kyoeisha Chemical Co., Ltd., trade name: UF-8001).

  The component (C) is a phosphinate (manufactured by Clariant, trade name: EXOLIT OP 935, phosphorus content = 23 mass%).

  The component (D) is 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (manufactured by Ciba Specialty Chemicals, trade name: I-369).

  The component (E) is a 75% by mass methyl ethyl ketone solution (trade name: BL3175, manufactured by Sumika Bayer Urethane Co., Ltd.) of an isocyanurate-based methyl ethyl ketone oxime block having hexamethylene diisocyanate as a base isocyanate.

  The component (F) is bisphenol A polyoxyethylene dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: BPE-10).

[Production of photosensitive element]
Next, each photosensitive resin composition solution prepared as described above is uniformly applied onto a 16 μm-thick polyethylene terephthalate film (trade name “G2-16”, manufactured by Teijin Limited), which is a separate support. Thus, a photosensitive resin composition layer was formed and dried at 100 ° C. for about 10 minutes using a hot air convection dryer. The film thickness after drying of the photosensitive resin composition layer was 38 μm.

  Subsequently, on the surface of the photosensitive resin composition layer opposite to the side in contact with the support layer, a polyethylene film (manufactured by Tamapoly Co., Ltd., trade name “NF-13”) is bonded as a protective film, and photosensitive. Got the element.

[Preparation of evaluation laminate]
The copper surface of a flexible printed wiring board substrate (trade name “F30VC1” manufactured by Nikkan Kogyo Co., Ltd.) obtained by laminating an 18 μm thick copper foil on a polyimide base material was polished with an abrasive brush, washed with water, and dried.

  Using a continuous vacuum laminator (trade name “HLM-V570” manufactured by Hitachi Chemical Co., Ltd.) on this flexible printed wiring board substrate, a heat shoe temperature of 100 ° C., a laminating speed of 0.5 m / min, and an atmospheric pressure of 4000 Pa or less. Then, under the condition of a pressure bonding pressure of 0.3 MPa, the obtained photosensitive element was laminated with the photosensitive resin composition layer on the copper foil side while peeling the polyethylene film to obtain a laminate for evaluation.

[Evaluation of light sensitivity]
On the obtained laminate for evaluation, a photo tool having a stove 21-step tablet as a negative was brought into close contact, and an HMW-201GX type exposure machine manufactured by Oak Manufacturing Co., Ltd. was used. The exposure was performed with an energy amount such that the number of steps remaining after development was 8.0. Then, after leaving still at normal temperature for 1 hour and peeling a PET film, it developed by spraying 1 mass% sodium carbonate aqueous solution of 30 degreeC for 40 second, and heated (dried) at 80 degreeC for 10 minutes. The above energy amount was used as a numerical value for evaluating the photosensitivity. The lower this value, the higher the photosensitivity. The results are shown in Table 2.

[Resolution evaluation]
A phototool having a stove 21-step tablet and a phototool having a wiring pattern with a line width / space width of 30/30 to 200/200 (unit: μm) as a negative for resolution evaluation are provided on the evaluation laminate. Using the above-described exposure apparatus, the exposure was performed with an energy amount such that the number of remaining steps after development of the stove 21-step tablet was 8.0. Then, after leaving still at room temperature for 1 hour and peeling a PET film, it developed by spraying 1 mass% sodium carbonate aqueous solution of 30 degreeC for 40 second, and heated (dry) for 10 minutes at 80 degreeC. Here, the resolution was evaluated based on the smallest value (unit: μm) of the space width between the line widths in which a rectangular resist shape was obtained by development processing. It shows that it is excellent in the resolution, so that this value is small. The results are shown in Table 2.

[Production of evaluation FPC]
A phototool having a stove 21-step tablet and a phototool having a wiring pattern as an evaluation negative are brought into close contact with the evaluation laminate, and the exposure machine described above is used to make the stove 21-step tablet The exposure was performed with an energy amount such that the number of steps remaining after development was 8.0. Next, after standing at room temperature for 1 hour, the PET film on the laminate is peeled off, spray development is performed under the same developer and development conditions as in the photosensitivity evaluation, and heating (drying) at 80 ° C. for 10 minutes. did. Subsequently, ultraviolet rays were irradiated with an energy amount of 1 J / cm ² using an ultraviolet irradiation device manufactured by Oak Manufacturing Co., Ltd., and further subjected to heat treatment at 160 ° C. for 60 minutes to obtain an evaluation FPC having a cover lay. It was.

[Evaluation of flexibility (folding resistance)]
The evaluation FPC obtained as described above was repeatedly folded 180 ° by goblet folding, and the number of bending until cracks occurred in the coverlay at that time was confirmed with an optical microscope while checking for cracks. Measured and evaluated according to the following criteria. The results are shown in Table 2.
A: No cracks are observed in the cover lay even when folded over 5 times.
B: The number of times until a crack is generated is 3 to 4 times.
C: The number of times until a crack is generated is 2 or less.

[Evaluation of flame retardancy]
The copper foil of the copper foil-clad laminate (manufactured by Nippon Steel Chemical Co., Ltd., product name “ESPANEX MB” series) was removed by etching to obtain a PI film having a thickness of 25 μm. Then, using a continuous vacuum laminator (trade name “HLM-V570”, manufactured by Hitachi Chemical Co., Ltd.) on both sides of the PI film, a heat shoe temperature of 100 ° C., a laminating speed of 0.5 m / min, and an atmospheric pressure of 4000 Pa or less. Then, under the condition of pressure bonding pressure of 0.3 MPa, the above photosensitive element was laminated with the photosensitive resin composition layer on the PI film side while peeling the polyethylene film to obtain a laminate.

  Next, using a HMW-201GX type exposure machine manufactured by Oak Seisakusho Co., Ltd., the exposure of each photosensitive resin composition layer of the above-described photosensitive element is performed using the stove 21-step tablet after the number of remaining steps. It was carried out with an energy amount of 8.0. Then, after leaving still at room temperature for 1 hour and peeling a polyethylene terephthalate film from a laminated body, it develops by spraying a 1 mass% sodium carbonate aqueous solution of 30 degreeC on a laminated body for 40 seconds, and 80 minutes at 80 degreeC. Heated (dried).

Next, the photosensitive resin composition layers (developed surfaces) on both sides of the laminate were irradiated with ultraviolet rays with an energy amount of 1 J / cm ² using an ultraviolet irradiation device manufactured by Oak Manufacturing Co., Ltd., and further heated at 160 ° C. for 60 minutes. By performing the treatment, a sample for flame retardancy evaluation in which a coverlay was formed was obtained. Using this flame retardant evaluation sample, a thin material vertical combustion test based on the UL94 standard was performed. Evaluation was expressed as VTM-0, VTM-1, or VTM-2 based on the UL94 standard. The results are shown in Table 2. Note that “NOT” in Table 2 indicates that the flame retardancy evaluation sample did not fall under VTM-0, VTM-1, or VTM-2 in the combustion test and was completely burned.

[Evaluation of warpage]
The evaluation FPC is cut to a certain size (20 mm × 25 mm) and left on a hot plate at 260 ° C. for 60 seconds, and then the horizontal reference surface is formed so that the surface on which the coverlay is formed is on the lower side. Placed on top. At this time, if the evaluation FPC is warped, the surface (lower surface) on which the cover lay is formed floats upward from the reference surface. The distance was measured. The distance of 3 mm or less was evaluated as A, 3 to 10 mm as B, and cylindrical as C.

[Evaluation of resilience (stiffness)]
The test FPC for evaluation was cut into a certain size (30 mm × 25 mm) to prepare a test piece, and in accordance with JIS L 1096 bending repulsion A method (Gurley method), Gurley stiffness tester (Tester Sangyo Co., Ltd.) The resilience (stiffness) was measured using In this measurement, the scale reading (RG, unit: mgf) when the test piece was separated from the pendulum was used as the repulsive value. The smaller this value, the lower the resilience.

  As is clear from Table 2, it was confirmed that the photosensitive resin compositions of Examples 1, 2, and 3 can provide sufficient photosensitivity and resolution. Moreover, it was confirmed that the laminated board provided with the cured film formed from the photosensitive resin composition of Example 1, 2, and 3 has sufficient flame retardance (VTM-0). Furthermore, it was confirmed that by using the photosensitive resin compositions of Examples 1, 2, and 3, an FPC with sufficiently reduced warpage and resilience was obtained.

It is a schematic cross section which shows suitable one Embodiment of the photosensitive element of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Photosensitive element, 10 ... Support body, 14 ... Photosensitive resin composition layer.

Claims (8)

(A) a novolac acid-modified vinyl group-containing epoxy resin having a biphenyl skeleton;
(B) a photopolymerizable compound having a urethane bond and an ethylenically unsaturated group in the molecule;
(C) a phosphorus-containing compound;
(D) a photopolymerization initiator;
The photosensitive resin composition containing this. The photopolymerizable compound (B) is
A urethane compound having a urethane bond derived from a reaction between a hydroxyl group at a terminal of a polycarbonate compound and / or a polyester compound and an isocyanate group of a diisocyanate compound and having an isocyanate group at a plurality of terminals;
A compound having a hydroxyl group and an ethylenically unsaturated group;
The photosensitive resin composition of Claim 1 containing the compound obtained by making this react. The photopolymerizable compound (B) is
It has a repeating unit represented by the following formula (1) and the following formula (2), and a molar ratio of the repeating unit represented by the following formula (1) and the repeating unit represented by the following formula (2) {formula A urethane / unsaturated organooligomer having (1) / formula (2)} of 9/1 to 1/9, wherein a copolycarbonate having a hydroxyl group at the terminal and having a number average molecular weight of 600 to 1000 and an organic isocyanate chain 3. The photosensitive composition according to claim 1, further comprising a urethane / unsaturated organooligomer having an unsaturated organooxycarbonylimide group bonded to a terminal of a urethane oligomer having a number average molecular weight of 1000 to 10,000 connected in a shape. Resin composition.

The (A) epoxy resin is a reaction between (a) an epoxy resin represented by the following general formula (3), (b) an unsaturated group-containing monocarboxylic acid, and (c) a polybasic carboxylic acid anhydride. The photosensitive resin composition as described in any one of Claims 1-3 containing the acid-modified vinyl group containing epoxy resin which is a product.

Wherein (3), ^{R 1} and ^{R 2} each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or represents an aryl radical, n is an integer of 0 to 50. In formula (3), a plurality of R ¹ and R ² may be the same or different. ] The photosensitive resin composition as described in any one of Claims 1-4 in which the said (C) phosphorus containing compound contains the phosphinic acid salt represented by following General formula (4).

[In Formula (4), A and B each independently represent a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group, and M represents Mg, Ca, Al, Sb, Sn. , Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, and K. m represents an integer of 1 to 4. ]   Furthermore, (E) The photosensitive resin composition as described in any one of Claims 1-5 containing a thermosetting agent.   The photosensitive resin composition as described in any one of Claims 1-6 which is for forming the cured film used as a permanent mask on a flexible substrate.   A photosensitive element provided with a support body and the photosensitive resin composition layer which consists of the photosensitive resin composition as described in any one of Claims 1-7 formed on this support body.

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