JP6781216B2 - Photosensitive resin composition - Google Patents

Description

The present invention is a photosensitive resin composition suitable for a coating material, for example, a coating material for protecting a conductor circuit pattern formed on a substrate such as a printed wiring board, and light obtained by photocuring the photosensitive resin composition. It relates to a cured product and a wiring board such as a printed wiring board coated with a photocurable film of the photosensitive resin composition.

In forming a solder-resist film on a printed wiring board, after forming a coating film of a photosensitive resin composition on the printed wiring board, a photomask is provided on the coating film to activate the entire surface of the printed wiring board with ultraviolet rays or the like. The exposure process may be performed by a batch exposure method of exposing with energy rays. During the exposure step, an oxime ester compound may be blended as a photopolymerization initiator in order to improve the sensitivity of the photosensitive resin composition.

As a photosensitive resin composition using an oxime ester compound as a photopolymerization initiator, for example, a photosensitive resin composition containing an oxime ester derivative-based polymerization initiator, an acid generator and / or a base generator polymerizable substance has been proposed. It has also been proposed to form a solder resist film using a sex resin composition (Patent Document 1).

In order to color the photosensitive resin composition using the oxime ester compound to a desired color, a colorant of a desired color may be added. Examples of the colorant to be blended in the photosensitive resin composition include a black colorant, a red colorant, a yellow colorant, a green colorant, a blue colorant, an orange colorant, a brown colorant (for example, amber) and the like. Among these, as a colorant, a colorant having a light color and high light transmittance, such as a green colorant, a blue colorant, an orange colorant, and a brown colorant, is blended in a photosensitive resin composition using an oxime ester compound. Then, since the sensitivity of the photosensitive resin composition is high, the light that reaches the substrate may be reflected during the exposure process, and the coating film may be halation.

Further, even in a photosensitive resin composition using an oxime ester compound and not using a colorant, halation may occur in the coating film during the exposure process as well. Further, even in a photosensitive resin composition that does not use an oxime ester compound as a photopolymerization initiator, halation may occur in the coating film depending on exposure conditions such as an exposure amount.

If halation occurs in the coating film during the exposure process, photocuring may extend to the non-exposed portion masked by the photomask on the coating film. Therefore, if, for example, a through hole or a blind via hole having a small diameter (for example, about φ50 to 200 μm) is provided in the non-exposed portion of the printed wiring board, it may be on the through hole or in the coating film developing process performed after the exposure process. There is a problem that the coating film applied on the blind via hole may not be developed. Further, there is a problem that halation occurs in the coating film, so that the line of the cured coating film may be undercut and an excellent line shape may not be imparted.

From the above, it is necessary to prevent halation when the photosensitive resin composition is exposed, and in particular, to prevent halation during exposure even with a highly sensitive photosensitive resin composition containing an oxime ester compound as a photopolymerization initiator. Is required.

Japanese Unexamined Patent Publication No. 2014-74165

In view of the above circumstances, the present invention can impart excellent line shape and resolution to a cured coating film by preventing halation during exposure, and reliably even a coating film on a small-diameter through hole or a blind via hole. An object of the present invention is to provide a photosensitive resin composition that can be developed.

（式中、Ｒ_１は、水素、炭素数１〜１７のアルキル基または炭素数１〜１７のアルコキシ基を表し、Ｒ_２は、フェニル基、または炭素数１〜５のアルキル基、−Ｏ−Ｃ_ｍＨ_２ｍ−ＣＨ_３及び−Ｏ−Ｃ_ｎＨ_２ｎ−Ｏ−Ｃ_ｐＨ_２ｐ−ＣＨ_３からなる群から選択された少なくとも１つの置換基で置換されたフェニル基を表し、ｍは０または１〜５の整数、ｎは１〜５の整数、ｐは０または１〜５の整数を表す。）で表される化合物である［３］に記載の感光性樹脂組成物。
［５］前記オキシムエステル化合物が、（９−エチル−６−ニトロ−９Ｈ−カルバゾール−３−イル）（４−（（１−メトキシプロパン−２−イル）オキシ）−２−メチルフェニル）メタノン Ｏ−アセチルオキシムである［３］または［４］に記載の感光性樹脂組成物。
［６］［１］乃至［５］のいずれか１つに記載の感光性樹脂組成物の光硬化物。
［７］［１］乃至［５］のいずれか１つに記載の感光性樹脂組成物の光硬化膜を有するプリント配線板。 The gist of the structure of the present invention is as follows.
[1] Photosensitivity containing (A) carboxyl group-containing photosensitive resin, (B) photopolymerization initiator, (C) epoxy compound, (D) colorant, and (E) photoreaction stabilizer. Sex resin composition.
[2] The photosensitive resin composition according to [1], wherein the photoreaction stabilizer (E) contains a dialkylaminobenzophenone compound.
[3] The photosensitive resin composition according to [1] or [2], wherein the (B) photopolymerization initiator contains an oxime ester compound.
[4] The oxime ester compound has the following general formula.

(In the formula, R ₁ represents hydrogen, an alkyl group having 1 to 17 carbon atoms or an alkoxy group having 1 to 17 carbon atoms, and R ₂ is a phenyl group or an alkyl group having 1 to 5 carbon atoms, −O−. _Represents a phenyl group substituted with at least one substituent selected from the group consisting of C _m H _2m- CH ₃ and -O-C _n H _2n- O-C _p H _2p- CH ₃ , where m is 0 or The photosensitive resin composition according to [3], which is a compound represented by an integer of 1 to 5, n is an integer of 1 to 5, and p is an integer of 0 or 1 to 5).
[5] The oxime ester compound is (9-ethyl-6-nitro-9H-carbazole-3-yl) (4-((1-methoxypropan-2-yl) oxy) -2-methylphenyl) methanone O. -The photosensitive resin composition according to [3] or [4], which is an acetyl oxime.
[6] The photocured product of the photosensitive resin composition according to any one of [1] to [5].
[7] A printed wiring board having a photocurable film of the photosensitive resin composition according to any one of [1] to [5].

According to the aspect of the present invention, the photosensitive resin composition contains a photoreaction stabilizer to prevent halation of the coating film during exposure and impart excellent line shape and resolution to the cured coating film. In addition, it is possible to reliably develop a coating film on a small-diameter through hole or a blind via hole.

According to the aspect of the present invention, since the photoreaction stabilizer contains a dialkylaminobenzophenone compound, even a photosensitive resin composition in which an oxime ester compound is used as a photopolymerization initiator is subjected to halation during exposure. Can be prevented more reliably.

According to the aspect of the present invention, even a photosensitive resin composition in which an oxime ester compound is used as a photopolymerization initiator can exhibit high sensitivity because it can prevent halation during exposure while having high sensitivity. At the same time, it is possible to impart excellent line shape and resolution and developability for a coating film on a small-diameter through hole or a blind via hole.

（式中、Ｒ_１は、水素、炭素数１〜１７のアルキル基または炭素数１〜１７のアルコキシ基を表し、Ｒ_２は、フェニル基、または炭素数１〜５のアルキル基、−Ｏ−Ｃ_ｍＨ_２ｍ−ＣＨ_３及び−Ｏ−Ｃ_ｎＨ_２ｎ−Ｏ−Ｃ_ｐＨ_２ｐ−ＣＨ_３からなる群から選択された少なくとも１つの置換基で置換されたフェニル基を表し、ｍは０または１〜５の整数、ｎは１〜５の整数、ｐは０または１〜５の整数を表す。）で表される化合物であることにより、感光性樹脂組成物の感度をより向上させつつ、より優れた解像性を付与することができる。また、感光性樹脂組成物の感度がより向上するので、光硬化に要する露光量を低減でき、結果、光硬化物の生産性を向上させることができる。 According to the aspect of the present invention, the oxime ester compound which is a photopolymerization initiator has the following general formula.

(In the formula, R ₁ represents hydrogen, an alkyl group having 1 to 17 carbon atoms or an alkoxy group having 1 to 17 carbon atoms, and R ₂ is a phenyl group or an alkyl group having 1 to 5 carbon atoms, −O−. _Represents a phenyl group substituted with at least one substituent selected from the group consisting of C _m H _2m- CH ₃ and -O-C _n H _2n- O-C _p H _2p- CH ₃ , where m is 0 or By being a compound represented by an integer of 1 to 5, n being an integer of 1 to 5, and p representing an integer of 0 or 1 to 5), the sensitivity of the photosensitive resin composition is further improved. It is possible to impart better resolution. Further, since the sensitivity of the photosensitive resin composition is further improved, the exposure amount required for photocuring can be reduced, and as a result, the productivity of the photocured product can be improved.

According to aspects of the invention, the oxime ester compound is (9-ethyl-6-nitro-9H-carbazole-3-yl) (4-((1-methoxypropan-2-yl) oxy) -2-methyl). By being a phenyl) methanone O-acetyloxime, it is possible to further improve the sensitivity of the photosensitive resin composition and to impart more excellent resolution.

Next, the photosensitive resin composition of the present invention will be described in detail. The photosensitive resin composition of the present invention comprises (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) an epoxy compound, (D) a colorant, and (E) photoreaction stability. Includes agents and.

(A) Carboxylic group-containing photosensitive resin The structure of the carboxyl group-containing photosensitive resin is not particularly limited, and for example, a photosensitive carboxyl group having one or more, preferably two or more photosensitive unsaturated double bonds. Examples include the contained resin. As the carboxyl group-containing photosensitive resin, for example, acrylic acid or methacrylic acid (hereinafter, "(meth) acrylic acid") may be added to at least a part of the epoxy groups of the polyfunctional epoxy resin having two or more epoxy groups in one molecule. A radically polymerizable unsaturated monocarboxylic acid such as) is reacted to obtain a radically polymerizable unsaturated monocarboxylic oxide epoxy resin such as epoxy (meth) acrylate, and the resulting radically polymerizable unsaturated monocarboxylic acid is obtained. Examples thereof include a polybasic acid-modified radically polymerizable unsaturated monocarboxylic oxide epoxy resin such as a polybasic acid-modified epoxy (meth) acrylate obtained by further reacting a hydroxyl group of the oxidized epoxy resin with a polybasic acid or an anhydride thereof. it can.

The chemical structure of the polyfunctional epoxy resin is not particularly limited as long as it is a bifunctional or higher functional epoxy resin. The epoxy equivalent of the polyfunctional epoxy resin is not particularly limited, but for example, the upper limit thereof is preferably 2000 g / eq, more preferably 1000 g / eq, and particularly preferably 500 g / eq from the viewpoint of the strength of the photocured product. .. On the other hand, the lower limit of the epoxy equivalent of the polyfunctional epoxy resin is preferably 100 g / eq. Examples of the polyfunctional epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin such as о-cresol novolac type, bisphenol A novolac type epoxy resin, and biphenyl type. Rubber-modified epoxy resin such as epoxy resin, naphthalene-type epoxy resin, dicyclopentadiene-type epoxy resin, silicone-modified epoxy resin, ε-caprolactone-modified epoxy resin, cyclic aliphatic polyfunctional epoxy resin, glycidyl ester-type polyfunctional epoxy resin, glycidyl Amin-type polyfunctional epoxy resin, heterocyclic polyfunctional epoxy resin, bisphenol-modified novolak-type epoxy resin, polyfunctional-modified novolac-type epoxy resin, condensate-type epoxy resin of phenols and aromatic aldehyde having a phenolic hydroxyl group, etc. Can be mentioned. Further, those in which halogen atoms such as Br and Cl are introduced into these resins can also be used. These epoxy resins may be used alone or in combination of two or more.

The radically polymerizable unsaturated monocarboxylic acid is not particularly limited, and examples thereof include (meth) acrylic acid, crotonic acid, and cinnamic acid, of which (meth) acrylic acid is preferable. The reaction method between the polyfunctional epoxy resin and the radically polymerizable unsaturated monocarboxylic acid is not particularly limited, and for example, the polyfunctional epoxy resin and the radically polymerizable unsaturated monocarboxylic acid are heated in an appropriate diluent. It can be reacted by doing so.

A free carboxyl group is introduced into the resin by reacting the polybasic acid and the polybasic acid anhydride with a hydroxyl group generated by the reaction of the polyfunctional epoxy resin and the radically polymerizable unsaturated monocarboxylic acid. The polybasic acid and the polybase anhydride are not particularly limited, and either saturated or unsaturated can be used. Specific polybasic acids include, for example, succinic acid, maleic acid, adipic acid, citric acid, phthalic acid, tetrahydrophthalic acid, 3-methyltetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, and 3-ethyltetrahydrophthalic acid. , 4-Ethyltetrahydrophthalic acid, Hexahydrophthalic acid, 3-Methylhexahydrophthalic acid, 4-Methylhexahydrophthalic acid, 3-Ethylhexahydrophthalic acid, 4-Ethylhexahydrophthalic acid, Methyltetrahydrophthalic acid, Examples thereof include methylhexahydrophthalic acid, endomethylenetetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, trimellitic acid, pyromellitic acid and diglycolic acid, and specific polybasic acid anhydrides include these anhydrides. Can be mentioned. These compounds may be used alone or in combination of two or more.

The above-mentioned polybasic acid-modified radically polymerizable unsaturated monocarboxylic oxide epoxy resin can also be used as a carboxyl group-containing photosensitive resin, but if necessary, the above-mentioned polybasic acid-modified radically polymerizable unsaturated monocarboxylic oxide epoxy resin can be used. By reacting a carboxyl group with a glycidyl compound having one or more radically polymerizable unsaturated groups and an epoxy group, a radically polymerizable unsaturated group is further introduced into the resin to further improve the photosensitivity. A group-containing photosensitive resin may be used.

In the carboxyl group-containing photosensitive resin in which a radically polymerizable unsaturated group is further introduced into the resin, the glycidyl compound reacts with the carboxyl group to form a side chain of a polybasic acid-modified radically polymerizable unsaturated monocarboxylic oxide epoxy resin skeleton. Since it binds to, the photopolymerization reactivity is further improved and it has excellent photosensitive characteristics. The compound having one or more radically polymerizable unsaturated groups and an epoxy group is not particularly limited, and for example, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, pentaerythritol triacrylate monoglycidyl ether, pentaerythritol trimethacrylate mono. Examples include glycidyl ether and the like. In addition, a plurality of glycidyl groups may be contained in one molecule. The above-mentioned compound having one or more radically polymerizable unsaturated groups and an epoxy group may be used alone or in combination of two or more.

The acid value of the carboxyl group-containing photosensitive resin is not particularly limited, but the lower limit thereof is preferably 30 mgKOH / g and particularly preferably 40 mgKOH / g from the viewpoint of obtaining reliable developability. On the other hand, the upper limit of the acid value of the carboxyl group-containing photosensitive resin is preferably 200 mgKOH / g from the viewpoint of preventing dissolution of the exposed portion by the alkaline developer, and 150 mgKOH from the viewpoint of moisture resistance of the photocured product and prevention of deterioration of electrical characteristics. / G is particularly preferable.

The mass average molecular weight of the carboxyl group-containing photosensitive resin is not particularly limited, but the lower limit thereof is preferably 3000 from the viewpoint of toughness of the photocured product and dryness to the touch, and particularly preferably 5000. On the other hand, the upper limit of the mass average molecular weight of the carboxyl group-containing photosensitive resin is preferably 200,000, particularly preferably 50,000, from the viewpoint of smooth developability.

Examples of carboxyl group-containing photosensitive resins marketed include Cyclomer P (ACA) Z-251 (Dycel Ornex Co., Ltd.), ZCR-1601H, KAYARAD ZAR-2000, ZFR-1122, FLX-2089. , ZCR-1569H (above, Nippon Kayaku Co., Ltd.), Lipoxy SP-4621 (Showa High Polymer Co., Ltd.) and the like. These resins may be used alone or in combination of two or more.

（式中、Ｒ_１は、水素、炭素数１〜１７のアルキル基または炭素数１〜１７のアルコキシ基を表し、Ｒ_２は、フェニル基、または炭素数１〜５のアルキル基、−Ｏ−Ｃ_ｍＨ_２ｍ−ＣＨ_３及び−Ｏ−Ｃ_ｎＨ_２ｎ−Ｏ−Ｃ_ｐＨ_２ｐ−ＣＨ_３からなる群から選択された少なくとも１つの置換基で置換されたフェニル基を表し、ｍは０または１〜５の整数、ｎは１〜５の整数、ｐは０または１〜５の整数を表す。）で表されるオキシムエステル化合物、１，２−オクタンジオン，１−〔４−（フェニルチオ）−２−（Ｏ−ベンゾイルオキシム）〕、エタノン，１−〔９−エチル−６−（２−メチルベンゾイル）−９Ｈ−カルバゾール−３−イル］−１−（０−アセチルオキシム）、２−（アセチルオキシイミノメチル）チオキサンテン−９−オン、１，８−オクタンジオン，１，８−ビス［９−エチル−６−ニトロ−９Ｈ−カルバゾール−３−イル］−，１，８−ビス（Ｏ−アセチルオキシム）、１，８−オクタンジオン，１，８−ビス［９−（２−エチルヘキシル）−６−ニトロ−９Ｈ−カルバゾール−３−イル］−，１，８−ビス（Ｏ−アセチルオキシム）等を挙げることができる。これらのオキシムエステル系光重合開始剤のうち、感度をより向上させつつ、より優れた解像性を付与することができる点から、上記一般式で表されるオキシムエステル系光重合開始剤が好ましく、このうち、（９−エチル−６−ニトロ−９Ｈ−カルバゾール−３−イル）（４−（（１−メトキシプロパン−２−イル）オキシ）−２−メチルフェニル）メタノン Ｏ−アセチルオキシムが特に好ましい。また、上記一般式で表されるオキシムエステル系光重合開始剤を用いると、上記の通り、感光性樹脂組成物の感度がより向上するので、光硬化に要する露光量を低減でき、結果、光硬化物の生産性を向上させることができる。 (B) Photopolymerization Initiator The photopolymerization initiator is not particularly limited, and examples thereof include an oxime ester compound (oxime ester-based photopolymerization initiator) from the viewpoint of imparting high sensitivity to the photosensitive resin composition. The oxime ester-based photopolymerization initiator is a compound having an oxime ester group. The oxime ester-based photopolymerization initiator is not particularly limited, and is, for example, (9-ethyl-6-nitro-9H-carbazole-3-yl) (4-((1-methoxypropan-2-yl) oxy)-. 2-Methylphenyl) methanone O-acetyloxime, etc.

(In the formula, R ₁ represents hydrogen, an alkyl group having 1 to 17 carbon atoms or an alkoxy group having 1 to 17 carbon atoms, and R ₂ is a phenyl group or an alkyl group having 1 to 5 carbon atoms, −O−. _Represents a phenyl group substituted with at least one substituent selected from the group consisting of C _m H _2m- CH ₃ and -O-C _n H _2n- O-C _p H _2p- CH ₃ , where m is 0 or An oxime ester compound represented by an integer of 1 to 5, n is an integer of 1 to 5, p is an integer of 0 or 1 to 5), 1,2-octanedione, 1- [4- (phenylthio). -2- (O-benzoyloxime)], etanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl] -1- (0-acetyloxime), 2- ( Acetyloxyiminomethyl) thioxanthene-9-one, 1,8-octanedione, 1,8-bis [9-ethyl-6-nitro-9H-carbazole-3-yl]-, 1,8-bis (O) -Acetyloxime), 1,8-octanedione, 1,8-bis [9- (2-ethylhexyl) -6-nitro-9H-carbazole-3-yl]-, 1,8-bis (O-acetyloxime) ) Etc. can be mentioned. Among these oxime ester-based photopolymerization initiators, the oxime ester-based photopolymerization initiator represented by the above general formula is preferable because it can impart more excellent resolution while further improving the sensitivity. Of these, (9-ethyl-6-nitro-9H-carbazole-3-yl) (4-((1-methoxypropan-2-yl) oxy) -2-methylphenyl) metanone O-acetyloxime is particularly preferred. preferable. Further, when the oxime ester-based photopolymerization initiator represented by the above general formula is used, as described above, the sensitivity of the photosensitive resin composition is further improved, so that the exposure amount required for photocuring can be reduced, and as a result, light The productivity of the cured product can be improved.

Further, in the photosensitive resin composition of the present invention, instead of the oxime ester-based photopolymerization initiator, another photopolymerization initiator other than the oxime ester-based photopolymerization initiator may be blended, and the oxime ester-based photopolymerization initiator may be blended. Other photopolymerization initiators may be blended with the initiator. The other photopolymerization initiator is not particularly limited as long as it is generally used, and for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether. Benzophenone-based photopolymerization initiators such as, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone and other acetophenone-based photopolymerization initiators, benzophenone, p-phenyl Initiation of benzophenone-based photopolymerization agents such as benzophenone, 4,4'-diethylaminobenzophenone, and dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiary butyl anthraquinone, and anthraquinone-based photopolymerization such as 2-aminoanthraquinone. Agents, thioxanthone-based photopolymerization initiators such as 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, ethyl-4- (dimethylamino) benzoate, 2 -N-Butoxyethyl-4- (dimethylamino) benzoate, methyl-4- (dimethylamino) benzoate, isoamyl-4- (dimethylamino) benzoate, 2- (dimethylamino) ethylbenzoate, 2-ethylhexyl-4 In addition to benzoate-based photopolymerization initiators such as- (dimethylamino) benzoate, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl-1- [4-- (Methylthio) Phenyl] -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,4- (2-hydroxyethoxy) phenyl-2 -(Hydroxy-2-propyl) ketone, benzyl dimethyl ketal, acetphenone dimethyl ketal, P-dimethylaminobenzoic acid ethyl ester, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, phenylbis (2,4,6-trimethylbenzoyl) ) Phenyl oxide and the like.

These photopolymerization initiators may be used alone or in combination of two or more.

The content of the photopolymerization initiator is not particularly limited, and when only the oxime ester-based photopolymerization initiator is blended, 0.10 parts by mass to 10 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin. Parts are preferable, 0.20 parts by mass to 5.0 parts by mass are more preferable, and 0.50 parts by mass to 2.0 parts by mass are particularly preferable. When an oxime ester-based photopolymerization initiator and another photopolymerization initiator are used in combination or only another photopolymerization initiator is used as the photopolymerization initiator, the amount of the carboxyl group-containing photosensitive resin is 100 parts by mass. It is preferably 0.20 parts by mass to 20 parts by mass, and particularly preferably 0.40 parts by mass to 10 parts by mass.

(C) Epoxy compound The epoxy compound is for increasing the crosslink density of the photocured product to obtain a photocured product such as a cured coating film having sufficient mechanical strength. Examples of the epoxy compound include an epoxy resin. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin (biphenyl novolac type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, etc.), bisphenol F and bisphenol S. Triazines such as bisphenol F type and bisphenol S type epoxy resins obtained by reacting epichlorohydrin, alicyclic epoxy resins, tris (2,3-epoxypropyl) isocyanurate, triglycidyltris (2-hydroxyethyl) isocyanurate, etc. Examples thereof include triglycidyl isocyanurate having a ring, dicyclopentadiene type epoxy resin, adamantan type epoxy resin, biphenyl aralkyl type epoxy resin, phenyl aralkyl type epoxy resin, and biphenyl type epoxy resin. These epoxy compounds may be used alone or in combination of two or more.

The content of the epoxy compound is not particularly limited, and is preferably 5.0 to 150 parts by mass, more preferably 10 to 100 parts by mass, and 15 to 50 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin. Part is particularly preferable.

(D) Colorant The colorant is not particularly limited to a pigment, a pigment, etc., and is also a white colorant, a black colorant, a red colorant, a yellow colorant, a green colorant, a blue colorant, an orange colorant, and brown. Any color such as a colorant and a purple colorant can be used. As will be described later, the photosensitive resin composition of the present invention contains a photoreaction stabilizer, so that the sensitivity is increased by using an oxime ester-based photopolymerization initiator, and as a colorant, a green colorant, Even if a light-colored and highly light-transmitting colorant such as a blue colorant, an orange colorant, or a brown colorant is blended, halation during exposure of the coating film of the photosensitive resin composition of the present invention is prevented. It is possible to impart an excellent line shape to the cured coating film, and it is possible to reliably develop a coating film on a small-diameter through hole or a blind via hole.

Examples of the green colorant and the blue colorant include phthalocyanine type and anthraquinone type. Examples of the orange colorant include diketopyrrolopyrrole. Examples of the brown colorant include amber. In addition, white colorants include titanium oxide, black colorants include carbon black, acetylene black, and perylene, and red colorants include azo, benzimidazolone, perylene, diketopyrrolopyrrole, and anthraquinone. Examples of the system, quinacridone system, and yellow colorant include azo system, benzimidazolone system, isoindolinone system, and anthraquinone system.

The content of the colorant is not particularly limited, and is preferably 0.10 to 10 parts by mass, particularly preferably 0.15 to 5.0 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin.

(E) Photoreaction Stabilizer Since the photosensitive resin composition contains a photoreaction stabilizer, halation is prevented when the coating film of the photosensitive resin composition is exposed and photocured, and the cured coating film is formed. An excellent line shape can be imparted, and even a coating film on a small-diameter through hole or a blind via hole can be reliably developed. That is, the photoreaction stabilizer functions as an anti-halation agent. Examples of the photoreaction stabilizer include dialkylaminobenzophenone compounds. By using the dialkylaminobenzophenone compound, halation during exposure can be more reliably prevented even in a highly sensitive photosensitive resin composition in which an oxime ester compound is used as a photopolymerization initiator. Examples of the dialkylaminobenzophenone compound include dimethylaminobenzophenone and diethylaminobenzophenone, of which 4,4'-bis (diethylamino) benzophenone is preferable.

The content of the photochemical reaction stabilizer is not particularly limited, and for example, the lower limit thereof reliably prevents undercutting of the coating film line without impairing the resolution, and obtains an excellent line shape. From the viewpoint of more reliable development even on a coating film on a small-diameter through hole or a blind via hole, 0.02 part by mass is preferable with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin, and 0.05 part by mass is more. It is preferable, and 0.10 parts by mass is particularly preferable. On the other hand, the upper limit of the content of the photochemical reaction stabilizer is that the active energy rays such as ultraviolet rays are sufficiently transmitted to the lower part of the coating film to obtain better sensitivity, resolution and line shape. From 1.0 part by mass is preferable, 0.70 part by mass is more preferable, and 0.40 part by mass is particularly preferable.

In addition to the above-mentioned components (A) to (E), the photosensitive resin composition of the present invention contains other components, for example, an organic filler, an extender pigment, a flame retardant, a curing accelerator, and a defoamer, if necessary. A foaming agent, a non-reactive diluent and the like can be appropriately blended.

Examples of the organic filler include (meth) acrylate monomers. Examples of the extender pigment include talc, barium sulfate, hydrophobic silica, alumina, aluminum hydroxide, mica and the like.

Examples of the flame retardant include a phosphorus-based flame retardant, and an organic phosphate-based flame retardant is preferable. Examples of the phosphorus-based flame retardant include tris (chloroethyl) phosphate, tris (2,3-dichloropropyl) phosphate, tris (2-chloropropyl) phosphate, tris (2,3-bromopropyl) phosphate, and tris (bromo). Halogen-containing phosphates such as chloropropyl) phosphate, 2,3-dibromopropyl-2,3-chloropropyl phosphate, tris (tribromophenyl) phosphate, tris (dibromophenyl) phosphate, and tris (tribromoneopentyl) phosphate. Esters; non-halogen aliphatic phosphates such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate; triphenyl phosphate, cresyldiphenyl phosphate, dicredylphenyl phosphate, tricresyl phosphate, trixylate Nylphosphate, xylenyldiphenyl phosphate, tris (isopropylphenyl) phosphate, isopropylphenyldiphenyl phosphate, diisopropylphenylphenyl phosphate, tris (trimethylphenyl) phosphate, tris (t-butylphenyl) phosphate, hydroxyphenyldiphenyl phosphate, octyldiphenyl phosphate Non-halogen aromatic phosphates such as aluminum trisdiphenylphosphine, aluminum trismethylethylphosphine, aluminum trisdiphenylphosphine, zinc bisdiphenylphosphine, zinc bismethylethylphosphine, zinc bisdiphenylphosphine, bisdiethyl Metal salts of phosphinic acids such as titanyl phosphinate, titanium tetrakisdiphenylphosphinate, titanyl bismethylethylphosphine, titanium tetrakismethylethylphosphine, titanyl bisdiphenylphosphine, titanium tetraxidiphenylphosphine, 9,10-dihydro-9 -HCA modification of oxa-10-phosphineanthrene-10-oxide (hereinafter HCA), addition reaction product of HCA and acrylic acid ester, addition reaction product of HCA and epoxy resin, addition reaction product of HCA and hydroquinone, etc. Type compound, diphenylvinylphosphine oxide, triphenylphosphine oxide, trialkylphosphine oxide, tris (hydroxyalkyl) phos Examples thereof include phosphine oxide compounds such as fin oxide.

Examples of the curing accelerator include dicyandiamide (DICY) and its derivatives, melamine and its derivatives, boron trifluoride-amine complex, organic acid hydrazide, diaminomaleonitrile (DAMN) and its derivatives, guanamine and its derivatives, and amineimide ( AI), polyamines and the like can be mentioned. Examples of the defoaming agent include silicone-based, hydrocarbon-based, and acrylic-based.

The non-reactive diluent is added to adjust the viscosity and dryness of the photosensitive resin composition. Examples of the non-reactive diluent include organic solvents. Examples of the organic solvent include ketones such as methyl ethyl ketone, aromatic hydrocarbons such as toluene and xylene, alcohols such as methanol, ethanol, isopropanol and cyclohexanol, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane. Petroleum-based solvents such as petroleum ether and petroleum naphtha, cellosolves such as cellosolve and butyl cellosolve, carbitols such as carbitol and butylcarbitol, ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate and butyl carbitol. Examples thereof include esters such as acetate, diethylene glycol monomethyl ether acetate, and ethyl diglycol acetate.

The method for producing the photosensitive resin composition of the present invention described above is not limited to a specific method. For example, after blending each of the above components in a predetermined ratio, at room temperature, a three-roll, ball mill, sand mill, bead mill, kneader. It can be produced by kneading or mixing by a kneading means such as, or a stirring and mixing means such as a super mixer, a planetary mixer, and a trimix. In addition, pre-kneading or pre-mixing may be performed before the kneading or mixing, if necessary.

Next, a method of using the photosensitive resin composition of the present invention described above will be described. Here, a case where the photosensitive resin composition of the present invention is applied as a solder resist film on a substrate on which a conductor circuit pattern of copper foil is formed will be described as an example.

A substrate such as a printed wiring board (rigid substrate) or a flexible printed wiring board (flexible substrate) having a circuit pattern formed by etching a copper foil from the photosensitive resin composition of the present invention produced as described above. A coating film is formed by applying it to a desired thickness using a known coating method such as screen printing, spray coater, bar coater, applicator, blade coater, knife coater, and roll coater. When the photosensitive resin composition of the present invention contains a non-reactive diluent after forming the coating film, 15 to 60 at a temperature of about 60 to 80 ° C. to volatilize the non-reactive diluent. Pre-drying by heating for about a minute is performed to form a tack-free coating film.

Next, a negative film (photomask) having a pattern that makes other than the desired development planned portion, such as a land, a through hole, and a blind via hole of a circuit pattern transparent, is brought into close contact with the coated photosensitive resin composition. Ultraviolet rays (for example, a wavelength in the range of 300 to 400 nm) are irradiated from above. Then, the coating film is developed by removing the unexposed region with a dilute alkaline aqueous solution. A spray method, a shower method, or the like is used as the developing method, and examples of the dilute alkaline aqueous solution used include a 0.5 to 5% by mass sodium carbonate aqueous solution. Next, a solder resist film having a desired pattern is formed on a circuit board such as a printed wiring board or a flexible printed wiring board by performing post-cure for 20 to 80 minutes in a hot air circulation type dryer or the like at 130 to 170 ° C. Can be made to.

Next, examples of the present invention will be described, but the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

Examples 1-6, Comparative Examples 1-5
Each component shown in Table 1 below is blended in the blending ratio shown in Table 1 below, and three rolls are used to mix and disperse at room temperature (25 ° C.) in Examples 1 to 6 and Comparative Examples 1 to 5. A photosensitive resin composition to be used was prepared. Unless otherwise specified, the blending amount of each component shown in Table 1 below is shown in parts by mass. In addition, the blank part of the blending amount in Table 1 means no blending.

The details of each component in Table 1 are as follows.
(A) Carboxylic group-containing photosensitive resin, KAYARAD ZAR-2000: Nippon Kayaku Co., Ltd. (solid content 65% by mass, diethylene glycol monoethyl ether acetate 25% by mass, solvent naphtha 10% by mass)
(B) Photopolymerization Initiator NCI-831: (9-Ethyl-6-Nitro-9H-Carbazole-3-yl) (4-((1-Methoxypropan-2-yl) oxy) -2-methylphenyl ) Metanon O-Acetyl Oxime, ADEKA CORPORATION
OXE-02: Etanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl] -1- (0-acetyloxime), BASF Japan Ltd. (C) Epoxy compound・ EPICLON 850-S: DIC Corporation

(D) Colorant, Chromophthal DPP Orange TR: Ciba Specialty Chemicals Co., Ltd., LIONOL BLUE FG-7351: Toyo Color Co., Ltd., LIONOL GREEN 2YG: Toyo Color Co., Ltd., Denka Black: Denka Co., Ltd. Stabilizer ・ Chivacure EMK: Chitec

Acrylic monomer ・ EBECRYL8405: Daicel Ornex Co., Ltd. Constitution pigment ・ Heidilite H42M: Showa Denko Co., Ltd. Flame retardant ・ Exolit OP-935: Clariant Japan Co., Ltd. Hardening accelerator ・ Melamine: Nissan Chemical Industries, Ltd. ・ DICY-7: Mitsubishi Chemical Co., Ltd. Defoaming agent X-50-1095C: Shin-Etsu Chemical Co., Ltd. Non-reactive diluent EDGAC: Sanyo Kasei Co., Ltd.

Specimen Preparation Step A substrate (glass epoxy substrate, "FR4", Cu thickness 25 μm) was surface-treated with dilute sulfuric acid (5% by mass), and then screen-printed to prepare the examples and comparative examples as described above. Each of the photosensitive resin compositions was applied. After coating, pre-drying was performed at 80 ° C. for 20 minutes in a BOX furnace. After pre-drying, the coating film was exposed to an exposure amount of 100 mJ / cm ² (apparatus: Oak Co., Ltd., direct drawing (DI) ultraviolet exposure apparatus "Mns60" (light source: high-pressure mercury lamp)). After the exposure, it was developed with a 1% by mass aqueous sodium carbonate solution at a development temperature of 30 ° C. and a spray pressure of 0.2 MPa. After development, a cured coating film was formed on the substrate by performing post-cure at 150 ° C. for 60 minutes in a BOX furnace. The thickness of the cured coating film was 20 to 23 μm.

Evaluation items (1) Sensitivity A step tablet for sensitivity measurement (Kodak LLC, 21 steps) was brought into close contact with the substrate that had been subjected to the pre-drying step of the test piece preparation process, and the test was performed through this step tablet. Ultraviolet irradiation (exposure) was performed under the exposure conditions of the piece manufacturing process. Then, development was carried out in the same manner as in the above-mentioned test piece manufacturing step to obtain a test piece. The maximum number of stages in which 100% of the sensitivity stages after development remained was evaluated as the sensitivity. The larger the number of stages, the better the sensitivity.

(2) Exposure at 7 steps of sensitivity A step tablet for sensitivity measurement (Kodak LLC, 21 steps) was brought into close contact with the substrate that had been subjected to the pre-drying step of the test piece manufacturing step, and passed through this step tablet. , The exposure amount was 30 to 300 mJ and the exposure was performed every 10 mJ with the above exposure apparatus. After that, development was carried out in the same manner as in the above-mentioned test piece preparation step, and the amount of exposure required for the step tablet to have 7 steps was determined.

(3) Minimum Via Opening Diameter A negative pattern having a via opening diameter of 50 to 200 μm is adhered onto the coating film as a negative mask for evaluation of resolution on the substrate that has been subjected to the preliminary drying step of the test piece manufacturing step. Through the negative mask, exposure was performed using the exposure apparatus at the exposure amount at the sensitivity of 7 steps. Then, development was carried out in the same manner as in the above-mentioned test piece manufacturing step, and the minimum via opening diameter at which vias could be opened was determined.

(4) Resolvability A photomask for evaluating resolution (a photomask having a pattern in which the line width and the space between lines are 30 μm to 130 μm) with respect to the substrate that has been subjected to the preliminary drying step of the test piece manufacturing step. Was brought into close contact with the coating film, and was exposed through this photomask with the exposure amount at the sensitivity of 7 steps using the exposure apparatus. Then, development was carried out in the same manner as in the above-mentioned test piece manufacturing step, and the thinnest line width (μm) remaining on the substrate in a perfect shape as a line was visually observed and evaluated as resolution.

(5) Undercut For a substrate on which a cured coating film having a width of 100 μm was formed, which was prepared according to the above test piece preparation step, the substrate was cut and the cut surface was observed with a scanning electron microscope (SEM), and the surface of the formation line The width (x) of the side end and the width (y) of the bottom side (deep side) end are measured, and the cross-sectional shape of the line where y is less than 5 μm narrower than x is “◎”, and y is 5 μm or more and less than 10 μm than x. The cross-sectional shape of the narrow line was evaluated as “◯”, and the cross-sectional shape of the line whose y was 10 μm or more narrower than x was evaluated as “x”.

The evaluation results are shown in Table 1 above. As shown in Table 1, in Examples 1 to 6 to which the photoreaction stabilizer was added, an orange colorant, a blue colorant, and a green colorant, which are light-colored and highly light-transmitting colorants, were used, and light was used. Even when an oxime ester compound was used as the polymerization initiator, undercutting was prevented for a line having a width of 100 μm, and an excellent line shape could be obtained. Further, in Examples 1 to 6, it was found that the minimum via opening diameter can be reduced to 60 to 80 μm, and the coating film on a small diameter through hole or a blind via hole can be reliably developed. Further, in Examples 1 to 6, an excellent resolution of 50 to 60 μm could be obtained. Furthermore, in Examples 1 to 6 in which the oxime ester compound was used as the photopolymerization initiator, excellent sensitivity could be obtained.

From Example 1 and Example 2, as an oxime ester-based photopolymerization initiator, (9-ethyl-6-nitro-9H-carbazole-3-yl) (4-((1-methoxypropan-2-yl) oxy) ) -2-Methylphenyl) In Example 1 using methanone O-acetyloxime, as an oxime ester-based photopolymerization initiator, etanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole) was used. Compared with Example 2 using -3-yl] -1- (0-acetyloxime), the sensitivity was further improved, and even better resolution could be obtained.

From Example 1 and Example 5, 0.2 parts by mass of the photoreaction stabilizer was added to Example 1, and the sensitivity was higher than that of Example 5 to which 0.5 part by mass of the photoreaction stabilizer was added. The resolution was further improved, and the line undercut could be further reduced. Further, from Examples 1 and 6, 0.2 parts by mass of the photoreaction stabilizer was added to Example 1, as compared with Example 6 in which 0.05 parts by mass of the photoreaction stabilizer was added. The minimum via opening diameter and line undercut could be further reduced.

On the other hand, in Comparative Examples 1 to 4 in which the photoreaction stabilizer was not added, photopolymerization was started by using an orange colorant, a blue colorant, and a green colorant, which are light-colored and highly light-transmitting colorants. When an oxime ester compound was used as the agent, undercut could not be prevented for a line having a width of 100 μm, and an excellent line shape could not be obtained. Further, in Comparative Examples 1 to 4, it was found that the minimum via opening diameter was 120 to 150 μm, and the coating film on the small diameter through hole or the blind via hole could not be sufficiently developed. In Comparative Example 5 in which a black colorant, which is a colorant having a dark color and low light transmittance, was added without adding a photoreaction stabilizer, the sensitivity was lowered and the resolution could not be obtained. In addition, undercut could not be prevented and an excellent line shape could not be obtained.

By preventing halation during exposure, the photosensitive resin composition of the present invention can impart excellent line shape and resolution to a cured coating film, and can be reliably applied to a coating film on a small-diameter through hole or a blind via hole. It is highly useful in the field of photocuring a coating film of a highly sensitive photosensitive resin composition containing an oxime ester-based photopolymerization initiator, and in particular, a colorant having a light color and a high light transmittance. It has high utility value in the field of photocuring the coating film of the blended highly sensitive photosensitive resin composition.

Claims (6)

A photosensitive resin composition containing (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) an epoxy compound, (D) a colorant, and (E) a photoreaction stabilizer. It ’s a thing ,
The (E) photoreaction stabilizer contains a dialkylaminobenzophenone compound and contains.
The photopolymerization initiator (B) is an oxime ester compound, and the oxime ester compound is the following general formula.

(In the formula, R ₁ represents hydrogen, an alkyl group having 1 to 17 carbon atoms or an alkoxy group having 1 to 17 carbon atoms, and R ₂ is a phenyl group or an alkyl group having 1 to 5 carbon atoms, −O−. _Represents a phenyl group substituted with at least one substituent selected from the group consisting of C _m H _2m- CH ₃ and -O-C _n H _2n- O-C _p H _2p- CH ₃ , where m is 0 or It is a compound represented by an integer of 1 to 5, n is an integer of 1 to 5, and p is an integer of 0 or 1 to 5).
The oxime ester compound is contained in an amount of 0.50 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the (A) carboxyl group-containing photosensitive resin, and the (E) photoreaction stabilizer is the above (A). ) A photosensitive resin composition containing 0.02 parts by mass or more and 0.40 parts by mass or less with respect to 100 parts by mass of a carboxyl group-containing photosensitive resin . The oxime ester compound is (9-ethyl-6-nitro-9H-carbazole-3-yl) (4-((1-methoxypropan-2-yl) oxy) -2-methylphenyl) methanone O-acetyloxime. The photosensitive resin composition according to claim 1 . The photosensitive resin composition according to claim 1 or 2, wherein the colorant (D) is at least one selected from the group consisting of diketopyrrolopyrrole, phthalocyanine blue and phthalocyanine green . The photosensitive resin composition according to claim 3, wherein the (D) colorant is contained in an amount of 0.15 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the (A) carboxyl group-containing photosensitive resin. .. The photocured product of the photosensitive resin composition according to any one of claims 1 to 4 . A printed wiring board having a photocurable film of the photosensitive resin composition according to any one of claims 1 to 4 .