JP2000075482A - Alkali developable photosensitive composition and formation of hardened coating using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a hardened coating having a prescribed pattern and excellent in various characteristics such as heat resistance and electric insulating property with good mass productivity without deteriorating the working environment by incorporating a photopolymerizable compd. which is liq. at a room temp., a specified acridine compd. and a photo-radical polymn. initiator or a mixture of a sensitizer and the initiator. SOLUTION: The alkali developable photosensitive compsn. contains a photopolymerizable compd. which is liq. at a room temp. and has one ethylenically unsatd. bond and one or more carboxyl groups in one molecule, an acridine compd. of the formula and a photo-radical polymn. initiator sensitive to active energy beams having a longer wavelength than the longest absorption wavelength of light which excites the acridine compd. and capable of initiating the radical polymn. of the photopolymerizable compd. under the active energy beams or a mixture of a sensitizer and the initiator. In the formula, R is 2-20C alkylene, oxadialkylene or thiodialkylene. When the compsn. is used, a hardened coating excellent in adhesion, electric insulating property, etc., is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solvent-free, alkali-developable photosensitive composition and a method for forming a cured film using the same.

[0002]

2. Description of the Related Art At present, a liquid photosensitive composition is widely used as a resist material used for a permanent film in the manufacture of a printed wiring board. For the development, an alkaline development type using a dilute alkaline aqueous solution is mainly used in consideration of environmental problems. As such an alkali developing type resist using a dilute alkali aqueous solution, for example, JP-A-61-243869 discloses a photosensitive composition obtained by adding an acid anhydride to an adduct of a novolak type epoxy compound and an unsaturated monobasic acid. A liquid composition comprising a hydrophilic resin, a photopolymerization initiator, a diluent, and an epoxy compound is disclosed.

[0003]

Most of the liquid alkali-developable photoresists currently used in the production of printed wiring boards that are currently on the market are coated with a negative film by applying a tack-free coating obtained by drying. And a contact exposure type for performing exposure. This type of resist is liquid at the time of application, so it has excellent followability to circuits and holes in printed wiring boards, and after drying, it is exposed by contacting a negative film to form a pattern, so it has excellent resolution. I have. Furthermore, this is a method that can also prevent reaction inhibition due to oxygen in the photoreaction. However, this method requires a drying step of several minutes, and releases a large amount of organic solvent into the atmosphere during drying, thus lowering productivity and workability and deteriorating the work environment and the global environment. There is a problem of causing.

On the other hand, as methods for solving such problems, there are a non-contact exposure type using a liquid photopolymerizable monomer instead of an organic solvent as a diluent, and a dry film method in which a photosensitive composition layer is formed on a support film. However, the non-contact exposure type has a problem that the resolution is inferior, and there is a problem that the liquid drips from a through hole on a circuit. On the other hand, the dry film method has a problem that the followability to irregularities and holes in the circuit is inferior to the contact exposure method.

Accordingly, it is an object of the present invention to provide a tack-free coating film which does not require a conventional drying step, while maintaining the advantages of the conventional liquid photosensitive composition and contact exposure as described above. Solvent-type, two-step exposure to form tack-free coatings and to form patterned cured coatings with excellent properties such as heat resistance, chemical resistance, adhesion to substrates, and electrical insulation. An object of the present invention is to provide an alkali-developable photosensitive composition having excellent workability and resolution. Further, the object of the present invention is to use such a photosensitive composition, for example, a solder resist of a printed wiring board, such as an etching resist, heat resistance of a predetermined pattern, a cured film excellent in various properties such as electrical insulation. Another object of the present invention is to provide a method that can be formed with good mass productivity without deteriorating the working environment.

[0006]

According to one aspect of the present invention, there is provided a solvent-free, alkali-developable photosensitive composition according to one aspect of the present invention.
(A) a room temperature liquid polymerizable compound having one ethylenically unsaturated bond and one or more carboxyl groups in one molecule, (B) a compound represented by the following general formula (1), and (C) A photoradical polymerization initiator capable of initiating radical polymerization of the photopolymerizable compound (A) in response to an active energy ray having a wavelength longer than the longest absorption wavelength of the compound (B) to excite the compound (B) Alternatively, it is characterized by containing a mixture of a sensitizer and a photo-radical polymerization initiator.

Embedded image

The second aspect of the alkali-developable photosensitive composition of the present invention is that (A) a liquid liquid at room temperature having one ethylenically unsaturated bond and one or more carboxyl groups in one molecule. A polymerizable compound, (B) a compound represented by the general formula (1), and (C) an active energy ray having a wavelength longer than the longest absorption wavelength of the compound (B) to excite the compound (B). A photo-radical polymerization initiator or a mixture of a sensitizer and a photo-radical polymerization initiator capable of initiating radical polymerization of the photo-polymerizable compound (A), and (D) having two or more epoxy groups in one molecule It is characterized by containing a compound.

In a preferred embodiment, as the component (C), a photo-radical polymerization initiator itself having an absorption wavelength of 400 nm or more, or a sensitizer having an absorption at a wavelength of 400 nm or more and a photo-radical polymerization initiator are used. A mixture is used, and the photosensitive composition further comprises (E) a compound having one ethylenically unsaturated bond in one molecule and / or (F) 1 in addition to the components (A) to (D). It can contain a compound having one ethylenically unsaturated bond and one or more hydroxyl groups in the molecule, and (G) a compound having a molecular weight of 1,000 or more and having two or more carboxyl groups in one molecule. Can be contained. The composition is preferably a liquid having a viscosity of 1,000 poise or less at room temperature from the viewpoints of application workability, followability to circuits and holes of a printed wiring board, and the like.

According to still another aspect of the present invention, a step of coating the photosensitive composition on a substrate, and coating the coating film obtained in the step with the compound (B) represented by the general formula (1) A) a primary exposure step in which the entire surface is exposed to an active energy ray having a wavelength longer than the longest wavelength of the absorption wavelength that excites to obtain a tack-free coating film; (B) a secondary exposure step of selectively irradiating an active energy ray containing a wavelength for exciting a predetermined pattern according to a predetermined pattern, and developing with an aqueous alkali solution to remove a non-exposed portion in the secondary exposure step to form a predetermined pattern. There is provided a method for forming a cured film, which comprises a developing step of forming a cured film. In another embodiment, in particular, in the formation of a cured film such as a solder resist for a printed wiring board using the photosensitive composition of the second embodiment, after the development step, irradiation with active energy rays and / or 100 to 180 ° C. Including a step of heating.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The photosensitive composition according to the present invention is basically characterized by containing the above-mentioned components (A) to (C) in combination. That is, in order to eliminate the drying step and the accompanying solvent evaporation which are problematic when using a conventional liquid photosensitive composition, and to maintain the above-mentioned advantages of using the liquid photosensitive composition, as a photocurable component. ,
It contains a photopolymerizable compound (A) which is liquid at room temperature (20 to 30 ° C) and has two types of functional groups, ie, an ethylenically unsaturated bond and a carboxyl group. can do. However, in order to enable contact exposure with excellent resolution, it is necessary to apply a composition on a substrate and then form a tack-free coating prior to selective exposure curing. Is a composition comprising the photopolymerizable compound (A) and containing no solvent, a tack-free coating film cannot be obtained by heating and drying.

Therefore, the photosensitive composition of the present invention may be combined with the above photopolymerizable compound (A) to obtain a compound of the formula (1)
And a light capable of initiating a radical polymerization of the photopolymerizable compound in response to an active energy ray having a wavelength longer than the longest absorption wavelength of the acridine compound (B) for exciting the compound. A radical polymerization initiator or a sensitizer is used in combination with a mixture (C) of a photoradical polymerization initiator. As a result, first, two-stage exposure of the primary exposure for exciting the component (C) and then the secondary exposure for exciting the component (B) becomes possible. Performs secondary exposure with good resolution by exposure, heat resistance, chemical resistance,
A patterned cured film having excellent properties such as adhesion to a substrate and electrical insulation can be formed.

That is, the photosensitive composition of the present invention is used as a substrate,
For example, a circuit-formed printed wiring board is applied by screen printing, a roll coater, a curtain coater, a spray, or the like, and the acridine compound (B) is not excited on the entire coated surface, but with a photoradical polymerization initiator or a sensitizer thereof. The mixture (C) is irradiated with an active energy ray to be excited. For example, in general, the acridine compound (B) contains 40
Since excitation is performed by irradiation with light having a wavelength of 0 nm or less, light such as a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a xenon lamp, or a halogen lamp is irradiated through a filter that cuts a wavelength of 400 nm or less (primary exposure). . As a result, the liquid photopolymerizable compound (A) undergoes radical polymerization to form a solid polymer having a carboxyl group in a side chain, and thus a tack-free coating film is obtained. Since this polymer has a carboxyl group in the side chain, it is soluble in a dilute aqueous alkaline solution, and becomes a component that will be dissolved in the subsequent development step.

Subsequently, the tack-free coating film is selectively applied directly or through a photomask having a predetermined exposure pattern formed thereon to an active energy ray containing a wavelength for exciting the acridine compound (B), for example, a high pressure mercury lamp, High pressure mercury lamp, metal halide lamp, xenon lamp, etc.
When ultraviolet light having a wavelength of 00 to 400 nm is irradiated (secondary exposure), the exposed portion becomes a cured film insoluble in an alkaline aqueous solution. Although the details of the curing reaction mechanism are not clear, there are mainly carboxyl groups on the side chains of the polymer of the photopolymerizable compound (A) and the acridine compound (B).
It is thought to be caused by the reaction of This is because the acridine compound causes some chemical reaction with the carboxyl group when heated or irradiated with active energy rays such as ultraviolet rays, and in particular, reacts instantaneously with the carboxyl group when irradiated with active energy rays having the absorption wavelength of the acridine compound. It is also apparent.

Next, when the cured film is developed with an aqueous alkaline solution, the polymer of the photopolymerizable compound present in the portion not exposed in the secondary exposure step has a carboxyl group in the side chain, and the unexposed portion is It is dissolved and removed by the aqueous alkali solution, leaving only a cured film having a predetermined pattern. After the development, it is preferable to perform washing and neutralization to remove an unnecessary developer. After the development step, the cured film is irradiated with active energy rays, or
It is preferable to heat to about 0 to 180 ° C. or to perform both treatments to completely cure. In particular, in the case of a photosensitive composition containing a polyfunctional epoxy compound (D) having two or more epoxy groups in one molecule, the curing reaction of the epoxy compound and the residual epoxy group due to the final finish curing by heating. The reaction of carboxyl groups that occur also occurs, electrical insulation, adhesion to the substrate, solder heat resistance,
In addition to acid resistance, alkali resistance, etc., a cured film excellent in various properties such as plating resistance, electroless plating resistance, and electric contact resistance can be obtained.

Hereinafter, the two-step exposure employed in the method for forming a cured film of the present invention will be described more specifically with reference to the accompanying drawings. FIG. 1 shows an example of the acridine compound (B) (trade name ADEKA OPT manufactured by Asahi Denka Kogyo Co., Ltd.).
N-1717, wherein in the general formula (1), R is -C ₇ H
₁₄ - with a compound of) a mixture of a photo-radical polymerization initiator or sensitizer and a photo-radical polymerization initiator (two of C) (bis (2,4,6-trimethylbenzoyl) - phenyl phosphine oxide (Ciba Manufactured by Specialty Chemicals Co., Ltd., trade name: Irgacure 819);
Cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium (trade name Irgacure 784, manufactured by Ciba Specialty Chemicals); and 2-methyl -1
6 parts by weight of-[4- (methylthio) phenyl] -2-morpholinoaminopropanone-1 (trade name Irgacure 907, manufactured by Ciba Specialty Chemicals) and 2,4
-Diethylthioxanthone (trade name DE manufactured by Nippon Kayaku Co., Ltd.)
TX) 0.2 parts by weight and 4,4'-bis (diethylamino) benzophenone (trade name EA, manufactured by Hodogaya Chemical Industry Co., Ltd.)
B) shows an absorption curve of 0.1 part by weight of the mixture), and FIG. 2 is an enlarged view of the absorbance in the wavelength range of 350 to 500 nm.

As shown in FIGS. 1 and 2, the acridine compound N-1717 has an absorption even at a wavelength slightly longer than 400 nm, but excites the acridine compound to form a carboxyl group of the photopolymerizable compound. It does not react and become insoluble. When a filter that cuts a wavelength of 400 nm or less is used, the acridine compound N-171 is used.
Most of the absorption wavelength portion of the absorption wavelength 7 is cut off. Therefore, when a visible light including a wavelength of 400 nm or more is irradiated using a filter that cuts a wavelength of 400 nm or less, only a photo-radical polymerization initiator or a mixture of a sensitizer and a photo-radical polymerization initiator is excited to cause photopolymerization. Radical polymerization of the reactive compound occurs, and a polymer having a carboxyl group in a side chain is generated. In short, in this primary exposure step, it is sufficient that active energy rays having a wavelength such that only the photoradical polymerization initiator or the mixture of the sensitizer and the photoradical polymerization initiator is sensitive can be irradiated. Thereafter, when ultraviolet rays having a wavelength of 400 nm or less capable of exciting the acridine compound are selectively exposed through a photomask (secondary exposure), as described above, the acridine compound and the polymer formed by the primary exposure (and the unreacted polymer) Carboxyl group of the (photopolymerizable compound) reacts to form a cured film insoluble only in the secondary exposure portion in the aqueous alkali solution. In the secondary exposure step, any active energy ray having a wavelength that can excite the acridine compound may be used, and a wavelength not involved in the excitation may be included.

Hereinafter, each component of the photosensitive composition of the present invention will be described. A photopolymerizable compound (A) which is liquid at room temperature and has one ethylenically unsaturated bond and one or more carboxyl groups in one molecule. Representative examples include acrylic acid, methacrylic acid, or hydroxyl-containing acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and phenylglycidyl ether (meth) acrylate. These photopolymerizable compounds can be used alone or in combination of two or more. Examples of dibasic acid anhydrides include phthalic anhydride, methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, maleic anhydride, itaconic anhydride, and nadic anhydride. And the like.

For the purpose of increasing the developability, heat resistance and reactivity, the compound (E) having one ethylenically unsaturated bond in one molecule and / or one molecule may be combined with the above photopolymerizable compound. Other photopolymerizable components such as a compound (F) having one ethylenically unsaturated bond and one or more hydroxyl groups therein can be used. Compound (E) having one ethylenically unsaturated bond in one molecule includes styrene, substituted styrene, vinyl compounds such as vinyl acetate, methyl (meth) acrylate, ethyl (meth) acrylate, lauryl (meth) acrylate, isopropyl Alkyl (meth) acrylates such as (meth) acrylate and t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate )
Acrylic esters such as acrylate, N-phenylmaleimide, N-cyclohexylmaleimide and the like can be mentioned.

The compound (F) having one ethylenically unsaturated bond and one or more hydroxyl groups in one molecule includes hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, And phenylglycidyl ether (meth) acrylate. In this specification, (meth) acrylate is a general term for acrylate and methacrylate.

Examples of the acridine compound (B) represented by the general formula (1) include 1,6-bis (9-acridinyl) hexane, 1,7-bis (9-acridinyl) heptane, and 1,8-bis (9-acridinyl) heptane. Bis (9-acridinyl) octane, 1,9-bis (9-acridinyl) nonane, 1,
Examples include 10-bis (9-acridinyl) decane, 1,11-bis (9-acridinyl) undecane, 1,12-bis (9-acridinyl) dodecane, and the like, which may be used alone or in combination of two or more. it can. These acridine compounds can be easily produced, for example, by reacting diphenylamine with a divalent carboxylic acid in the presence of a metal oxide.

Next, the component (C) includes (C-
1) It is capable of initiating radical polymerization of the photopolymerizable component in response to an active energy ray having a wavelength longer than the longest absorption wavelength that excites the acridine compound, preferably 400 nm. As described above, a photo-radical polymerization initiator having absorption in a region of preferably 420 nm or more, or a mixture of a photo-radical polymerization initiator and a sensitizer exhibiting the same action as in (C-2) can be used.

Examples of the photoradical polymerization initiator (C-1) include α-diketones such as camphorquinone, benzyl and 4,4′-dimethoxybenzyl; Michler's ketone;
Benzophenones such as 4,4'-bisdiethylaminobenzophenone; 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 1-
Anthraquinones such as chloroanthraquinone; 2,4-
Thioxanthones such as dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone and 2,4-diisopropylthioxanthone; 2,4,6
-(Bis) acylphosphine oxides such as trimethylbenzoyldiphenylphosphine oxide; bis (2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl)- And titanocenes such as phenyl) titanium. On the other hand, the mixture (C-2) includes 2-
Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-methyl-1- [4
-(Methylthio) phenyl] -2-morpholinoaminopropanone-1 and other aminoacetophenones and thioxanthones or aminobenzophenones; benzophenones and aminobenzophenones; peroxides and leuco dyes or 4 , 4-bisdiethylaminobenzophenone, etc.
As described above, a combination in which an initiator having no absorption and a compound having absorption at 400 nm or more exhibit a sensitizing effect can be used. These photo-radical polymerization initiator components (C-
1 and C-2) can be used alone or as a mixture of two or more kinds (or a combination mixture). Further, a tertiary amine such as triethanolamine, a photoinitiating assistant such as isoamyl dimethylaminobenzoate and dimethylaminoethyl methacrylate can be used. Agents can be added.

The mixing ratio of the acridine compound (B) and the photoradical polymerization initiator component (C: C-1 and C-2) is such that the acridine compound (B) is 100 parts by weight of the photopolymerizable compound (A). The amount is suitably 1 to 50 parts by weight, more preferably 5 to 30 parts by weight. If the amount of the acridine compound is less than the above range, it is impossible to form an image. Conversely, if it is more than the above range, storage stability is deteriorated and gelation tends to occur with time, which is not preferable.
On the other hand, the mixing ratio of the photoradical polymerization initiator component (C) is
0.5 to 100 parts by weight of the photopolymerizable compound (A)
30 parts by weight is suitable, and more preferably 1 to 20 parts by weight. When the amount of the photoradical polymerization initiator component is less than the above range, the reactivity at the time of light irradiation is poor, the coating film remains wet even after the primary exposure, and conversely, when the amount exceeds the above range, the developability is poor. And the electrical properties of the cured film tend to deteriorate. The relationship between the components (B) and (C) is that the absorption wavelength of the photoradical polymerization initiator component (C) is at least 10 nm longer than the longest wavelength of the acridine compound (B). Is preferred. The absorption wavelength of the acridine compound (B) is 320 nm
~ 400 nm, and the longest absorption wavelength is 10 times longer than the longest absorption wavelength of the photo-radical polymerization initiator component (C).
It is preferably on the low wavelength side of at least nm. More preferably, the absorption wavelength of the photo-radical polymerization initiator component (C) exists at a wavelength longer than 20 nm from the longest absorption wavelength of the acridine compound (B).

The photosensitive composition according to the second aspect of the present invention has the following properties for the purpose of improving adhesion, heat resistance, electrical properties and coatability.
The compound (D) having two or more epoxy groups in the molecule is contained. Such polyfunctional epoxy compounds include, for example, bisphenol A type, hydrogenated bisphenol A type, bisphenol F type, bisphenol S type, phenol novolak type, cresol novolak type, bisphenol A novolak type, biphenol type, bixylenol type , N-glycidyl type, triglycidyl isocyanurate, and other commonly used epoxy compounds can be used alone or in combination of two or more, and the amount thereof is 0 to 300 parts by weight per 100 parts by weight of the photopolymerizable compound (A). The part is appropriate. If the amount of the polyfunctional epoxy compound is too large, the developability is undesirably reduced. Further, in order to accelerate the reaction between the epoxy compound and the carboxyl group and the curing reaction of the epoxy group, dicyandiamide,
Known and commonly used catalysts such as imidazoles and triphenylphosphine can be added. In addition, the photosensitive composition of the present invention can be formed into a one-part composition when such a thermosetting component is not added, but the photopolymerizable compound ( It is preferable to form a two-part composition of A), a main component mainly composed of a photoradical polymerization initiator component (C), and a curing agent mainly composed of an acridine compound (B) and a polyfunctional epoxy compound (D). .

The photosensitive composition of the present invention may further contain, if necessary, one coat for the purpose of improving coatability, heat resistance and developability.
Molecular weight 1, having two or more carboxyl groups in the molecule
It can contain 000 or more compounds (G) (oligomers, polymers). Representative compounds include a copolymer of styrene and (meth) acrylic acid, an alcohol adduct of a copolymer of styrene and maleic anhydride, and the like, and may be used alone or in combination of two or more. it can. The addition amount is suitably from 0 to 200 parts by weight per 100 parts by weight of the photopolymerizable compound (A).

The photosensitive composition of the present invention further comprises barium sulfate, barium titanate, silicon oxide powder, finely divided silicon oxide, amorphous silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide Known or commonly used inorganic fillers such as mica, mica, etc., silane coupling agents for improving the wettability between them and the resin, and titanate-based and aluminum-based coupling agents can be used alone or in combination. These are effective in improving properties such as adhesion of the cured film to the substrate and hardness.

Further, if necessary, known and commonly used coloring agents such as phthalocyanine green, phthalocyanine blue, disazo yellow, crystal violet, titanium oxide and carbon black, known and commonly used thixotropic agents such as orben, benton and montmorillonite, and silicone-based A known and commonly used antifoaming agent or leveling agent such as a fluorine-based or polymer-based one can also be added.

When the liquid photosensitive composition having the above composition is used as a solder resist for a printed wiring board, for example, a screen printing method, a curtain coating method, a spray coating method, It is applied by a method such as a roll coating method.
By irradiating the entire coated surface with active energy rays through a filter that cuts ultraviolet light having a wavelength of 0 nm or less, a tack-free coating film can be formed. Thereafter, the resist pattern is selectively exposed to active energy rays through a photomask on which a predetermined exposure pattern is formed, and the unexposed portions are developed with a dilute alkaline aqueous solution to form a resist pattern. By final curing by heating at ℃ or both, adhesion, hardness,
A resist film excellent in resolution, solder heat resistance, chemical resistance, solvent resistance, and electrical insulation is formed.

As the alkaline aqueous solution, an alkaline aqueous solution of potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines and the like can be used.

As an irradiation light source for photocuring, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a halogen lamp, a xenon lamp, a metal halide lamp, and the like are suitable for primary exposure. In addition, visible light, laser light and the like can also be used as active light for exposure. As a light source for the secondary exposure, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, and the like are suitable. Further, the filter that cuts ultraviolet rays used in the primary exposure cuts 95% or more of the light having the absorption wavelength of the acridine compound (B) and 10% of the light having the absorption wavelength of the photo-radical polymerization initiator component (C). What transmits above is preferable.

[0031]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but it is needless to say that the present invention is not limited to the following examples. Note that “parts” and “%” are all based on weight unless otherwise specified.

Examples 1 to 4 The components shown in Table 1 below were blended, stirred, and ground with a three-roll mill to obtain a photosensitive composition. The viscosities of each composition were all in the range of 100 to 1,000 poise and were liquid. Each of the obtained photosensitive compositions was tested for developability, dryness to touch, and solder heat resistance by the methods described below. The results are shown in Table 1.

[Table 1]

Comparative Example 1 A photosensitive composition was prepared in the same composition and in the same blending ratio as in Example 4 except that the photopolymerizable compound CB-MHP having a carboxyl group was not blended. No final cured film could be obtained from the product.

Examples 5 to 8 The components shown in Table 2 below were mixed, stirred, and kneaded with a three-roll mill to separately prepare solution a and solution b. The photosensitive composition obtained by mixing was used for the test. The viscosity of each photosensitive composition is 100 to 1,
It was in the range of 000 poise and was liquid. Each of the obtained photosensitive compositions was tested for developability, touch dryness, solder heat resistance, heat resistance, electrical insulation, electrolytic corrosion resistance, and electroless gold plating resistance by the methods described below. The results are also shown in Table 2.

[Table 2]

Comparative Example 2 In Example 5, the acridine compound N-1717 was used.
A photosensitive composition was prepared with the same composition and the same blending ratio except that was not blended, but a final cured film could not be obtained from this photosensitive composition.

Comparative Example 3 A photosensitive composition was prepared in the same composition and in the same blending ratio as in Example 7 except that the photoradical polymerization initiator Irgacure 819 was not blended. No hardened film could be obtained.

(1) Evaluation of Developability The composition of each of the above Examples was entirely printed on a patterned copper foil substrate by screen printing, and a metal halide lamp 80W3 using a filter for cutting a wavelength of 400 nm or less, The entire surface was exposed under the condition of a conveyor speed of 3 m / min to form a dry coating film. Thereafter, the film was developed with a 1% aqueous solution of sodium carbonate at a spray pressure of 2 kg / cm ² for 60 seconds, and the developability of the coating film was examined. The criteria are as follows. ：: No coating film remains on the substrate. Δ: The coating film remains only on the copper foil. ×: The coating film remains on the entire surface of the substrate.

(2) Drying to the touch The composition of each of the above examples was entirely printed on a patterned copper foil substrate by screen printing, and a metal halide lamp 80W3 using a filter that cuts a wavelength of 400 nm or less. The entire surface was exposed at a conveyor speed of 3 m / min to form a dry coating film. The dried film was pressed with a finger, and the dried state was evaluated. The criteria are as follows. ：: no stickiness, no fingerprint left X: Stickiness and fingerprint remain.

Characteristic test: The composition of each of the above examples was entirely printed on a copper foil substrate on which a pattern was formed by screen printing, and a metal halide lamp 80W3 using a filter that cuts a wavelength of 400 nm or less, and a conveyor speed 3m. The whole surface was exposed under the condition of / min to form a dry coating film. A negative film was applied to this substrate, and the resist pattern was exposed with an ultra-high pressure mercury lamp, and the spray pressure was 2 kg / cm.
^The pattern was formed by developing with an aqueous sodium carbonate solution of No. ² . This substrate is integrated in a UV conveyor furnace with an integrated exposure of 1000 mJ.
/ Cm ² at 150 ° C. for 30 seconds.
An evaluation substrate was prepared by heat curing. The obtained evaluation board was tested for the following characteristics.

(3) Solder heat resistance The evaluation substrate coated with the rosin-based flux was
After immersing in a solder bath set at 30 ° C. for 30 seconds and washing the flux with denatured alcohol, the blistering, peeling and discoloration of the resist layer were evaluated visually. The criteria are as follows. ：: no change observed at all △: slight change ×: swelling and peeling of coating film

(4) Acid Resistance The above evaluation substrate was immersed in a 10 vol% sulfuric acid aqueous solution at room temperature for 10 minutes, washed with water, and then subjected to a peel test with a cellophane adhesive tape to evaluate the peeling and discoloration of the resist layer. The criteria are as follows. ：: no change observed at all △: slight change ×: peeling of coating film

(5) Insulation Characteristics An evaluation substrate was prepared under the above conditions using a comb electrode B coupon of IPC B-25, and DC50 was applied to the comb electrode.
A bias of 0 V was applied, and the insulation resistance was measured.

(6) Electric Corrosion Resistance An evaluation substrate was prepared under the above-mentioned conditions using a comb electrode B coupon of IPC B-25, and DC10 was applied to the comb electrode.
0V bias, 60 ° C., 90% R.C. H. Was checked for migration after 500 hours in a constant temperature / humidity bath. The criteria are as follows. ：: no change observed at all △: slight change ×: migration occurred

(7) Electroless Gold Plating Resistance Using a commercially available electroless nickel plating bath and electroless gold plating bath, plating is performed under the conditions of nickel 5 μm and gold μm, and peeling of the resist layer is performed by tape peeling. The presence / absence and the presence / absence of seepage of the plating solution between the substrate and the resist layer were evaluated. The criteria are as follows. ：: No change was observed at all △: Slight peeling and seepage ×: Peeling of resist layer

[0045]

As described above, the photosensitive composition of the present invention is a solvent-free type which does not require a drying step as in the prior art for forming a tack-free coating film, and has a tack-free coating by two-step exposure. Alkaline development with excellent workability and resolution that can form a patterned cured film with excellent properties such as film formation and heat resistance, chemical resistance, adhesion to substrates, electrical insulation, etc. A photosensitive composition. Therefore, by using the photosensitive composition of the present invention, for example, a cured film excellent in various properties such as heat resistance of a predetermined pattern and electrical insulation properties, such as a solder resist of a printed wiring board and an etching resist, can reduce the working environment. It can be formed with good mass productivity without deterioration.

[Brief description of the drawings]

FIG. 1 is a graph showing absorption curves of typical examples of an acridine compound, a photoradical polymerization initiator, and a mixture of a sensitizer and a photoradical polymerization initiator.

FIG. 2 is a graph showing an enlarged absorbance in a wavelength range of 350 to 500 nm of the absorption curve shown in FIG.

Continued on front page F term (reference) 2H025 AA00 AA02 AA04 AA06 AA07 AA08 AA10 AA14 AA20 AB15 AC01 AD01 BC12 BC31 BC33 BC34 BC81 BC85 BC86 BC92 BC94 CA00 CA01 CA28 CC17 FA05 FA06 FA17 FA29 FA30 4J011 QA02 QA03 QA03 QA03 QA03 RA37 SA90 TA03 TA06 UA01 UA02 UA06 UA08 WA01

Claims (8)

[Claims] (A) a photopolymerizable compound having one ethylenically unsaturated bond and one or more carboxyl groups in one molecule, which is liquid at room temperature; and (B) a compound represented by the following general formula (1). And (C) radical polymerization of the photopolymerizable compound (A) can be initiated in response to an active energy ray having a wavelength longer than the longest absorption wavelength for exciting the compound (B). An alkali-developable photosensitive composition comprising a photoradical polymerization initiator or a mixture of a sensitizer and a photoradical polymerization initiator. Embedded image (A) a photopolymerizable compound having one ethylenically unsaturated bond and one or more carboxyl groups in one molecule, which is liquid at room temperature; and (B) a compound represented by the following general formula (1). (C) light capable of initiating radical polymerization of the photopolymerizable compound (A) in response to an active energy ray having a wavelength longer than the longest absorption wavelength for exciting the compound (B). An alkali development type photosensitive composition comprising: a radical polymerization initiator or a mixture of a sensitizer and a photoradical polymerization initiator; and (D) a compound having two or more epoxy groups in one molecule. Embedded image 3. The method according to claim 1, wherein the component (C) has a thickness of 400 nm.
The composition according to claim 1, wherein the composition is a photoradical polymerization initiator having the above absorption wavelength, or a mixture of a sensitizer having absorption at a wavelength of 400 nm or more and a photoradical polymerization initiator. Further, (E) a compound having one ethylenically unsaturated bond in one molecule and / or (F) a compound having one ethylenically unsaturated bond and one or more hydroxyl groups in one molecule. The composition according to any one of claims 1 to 3, further comprising: 5. The composition according to claim 1, further comprising (G) a compound having a molecular weight of 1,000 or more and having two or more carboxyl groups in one molecule. object. 6. The composition according to claim 1, wherein the composition is a liquid having a viscosity of 1,000 poise or less at room temperature. 7. A step of applying the photosensitive composition according to claim 1 on a substrate, and a coating film obtained in the step is represented by the general formula (1). Exposure step to obtain a tack-free coating by exposing the entire surface to an active energy ray having a wavelength longer than the longest absorption wavelength of the compound (B) to excite the compound (B) to be excited, and the coating obtained in the primary exposure step A second exposure step of selectively irradiating an active energy ray containing a wavelength for exciting the compound (B) according to a predetermined pattern, and developing with an alkaline aqueous solution to remove a non-exposed portion in the second exposure step. A method for forming a cured film, comprising a developing step of forming a cured film having a predetermined pattern. 8. The method according to claim 7, further comprising, after the developing step, a step of irradiating with active energy rays and / or heating to 100 to 180 ° C.