JP2750461B2 - Photopolymerizable composition - Google Patents

Description

The present invention relates to a novel photopolymerizable composition,
More specifically, the present invention relates to a photopolymerizable composition having improved adhesion (adhesion or adhesion) to a metal.

(Prior Art) Various photopolymerizable compositions which can be developed with an alkaline developer have been proposed as photoresists for forming printed wiring boards, printing boards and metal relief images (JP-A-63-202740, JP-A-64-202). 10235). This photopolymerizable composition is usually used not only as a solution dissolved in an organic solvent but also as a dry film in which the photopolymerizable composition is laminated between a polyester base film and a polyolefin film.

In this dry film, the polyolefin-based film is peeled off and laminated on a copper-clad laminate for a printed board, a support for a printed board, a metal substrate, etc., but the conventional photopolymerizable composition has poor adhesion. Various undesirable phenomena occur during etching or plating. For example,
Phenomena such as undercut when spraying the etching solution and infiltration of the plating solution into the resist interface when the plating solution is immersed occur, and as a result, it is often experienced that the expected wiring cannot be obtained.

(Problems to be solved by the invention) An object of the present invention is to solve the above-mentioned disadvantages of the prior art,
Moreover, it is an object of the present invention to provide a novel photopolymerizable composition having improved adhesion to a metal surface. A further object of the present invention is to provide a photopolymerizable composition capable of reproducing a faithful image image of an original plate and exhibiting high resolution.

(Constitution of the Invention) As a result of earnest studies, the present inventors have found that a polymerizable monomer having a ε-caprolactone-modified (meth) acrylate ester as an essential component and having a carboxyl group, a styrene monomer,
The present inventors have found that a photopolymerizable composition containing a thermoplastic polymer composed in combination with an acrylic ester and a methacrylic ester is suitable for the purpose, and have completed the present invention.

That is, the present invention is a photopolymerizable composition containing a thermoplastic polymer compound having a polycaprolactone side chain, a liquid or solid addition polymerizable compound at normal temperature and normal pressure, and a photopolymerization initiator, The polymer compound is a copolymer compound of a polycaprolactone structure-containing monomer represented by the following formula (I) and a vinyl monomer represented by the following formula (II).

(However, n = 1 to 5, wherein R _{1 to} R ₇ represent a hydrogen atom or an alkyl group.) (Wherein, R _{8 to} R ₁₁ represent a hydrogen atom, an alkyl group, an aromatic ring or a halogen atom or an alkyl ester group, or a carboxyl group). A typical monomer of the above formula (I) is ε-caprolactone-modified (Meth) acrylic acid ester, the above (I
Representative monomers of the formula (I) include polymerizable monomers having a carboxyl group, styrenic monomers, acrylates and methacrylates. The specific composition ratio is preferably as follows.
That is, ε-caprolactone-modified (meth) acrylic acid ester 1 to 20% by weight Polymerizable monomer having a carboxyl group 15 to 40% by weight Styrenic monomer 1 to 35% by weight Acrylic acid ester and methacrylic acid ester 84 to 25% by weight Carboxyl Examples of the polymerizable monomer having a group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, propionic acid, sorbic acid, and cinnamic acid, and at least one of them is used. Among the polymerizable monomers having a carboxyl group, acrylic acid and methacrylic acid are preferred. In addition, dicarboxylic acids such as maleic acid can be used as half esters or anhydrides. The polymerizable monomer having a carboxyl group contributes to the alkali developability of the photopolymerizable composition.

Examples of the styrene monomer include styrene; α-substituted styrene in which the α-position is substituted with an alkyl group or a halogen atom, for example, α-methylstyrene, α-chlorostyrene, and the like; substituted styrene in which a benzene ring is substituted, for example,
p-methylstyrene, p-ethylstyrene, p-propylstyrene, p-isopropylstyrene, p- (tert-
Butyl) styrene and the like, and at least one kind is used. Among the styrene monomers, styrene, α-methylstyrene and the like are preferred.

As the acrylate, an acrylate having an alkyl group having 1 to 20 carbon atoms, for example, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, tert-acrylate -Butyl, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, dodecyl acrylate, stearyl acrylate and the like. . Examples of the methacrylate include methacrylate corresponding to the above acrylate. One or more of these acrylates and methacrylates are used.

The acrylate is used in combination with the methacrylate. Even when either one is combined with the styrene-based monomer, the resolution of the photopolymerizable composition is not sufficient.

In order to further improve the resolution, the acrylate is preferably an acrylate having an alkyl group having 7 or more carbon atoms, and the methacrylate is preferably a methacrylate having an alkyl group having 1 to 3 carbon atoms. Is preferred. In particular, it is preferable to use a combination of an acrylate having an alkyl group having 7 or more carbon atoms and a methacrylate having an alkyl group having 1 to 3 carbon atoms.

Thermoplastic polymers are modified with ε-caprolactone (meth)
Acrylic acid ester 1 to 20% by weight, carboxyl group-containing polymerizable monomer 15 to 40% by weight, preferably 20 to 35% by weight, styrene monomer 1 to 35% by weight, preferably 10 to 10%
3333% by weight, acrylates and methacrylates in an amount of 84-25% by weight, preferably 70-32% by weight. When the ratio of each monomer is out of the above range, the resolution is reduced.

Further, the ratio between the acrylate and the methacrylate can be appropriately set within a range that does not reduce the resolution, but acrylate / methacrylate = 20 to 65/80 to 35% by weight, preferably 30 to 50% by weight. / 70-50% by weight.

The thermoplastic polymer can be obtained by a conventional polymerization method such as solution polymerization, bulk polymerization, turbidity polymerization, and emulsion polymerization of the three-component monomer.

Examples of the addition polymerizable compound include acrylates and methacrylates which are liquid or solid at normal temperature and normal pressure and have two or more acryloyl groups or methacryloyl groups in the molecule.

Examples of the acrylate having two acryloyl groups in the molecule include ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, propylene glycol diacrylate, and dipropylene glycol. Diacrylate, tripropylene glycol diacrylate, tetrapropylene glycol diacrylate, polypropylene glycol diacrylate, 1,4-butanediol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, ethylene oxide addition of bisphenol A Diacrylate, bisphenol A propylene oxide adduct dia Acrylate, diacrylate of ethylene oxide adduct of hydrogenated bisphenol A, diacrylate of propylene oxide adduct of hydrogenated bisphenol A, N, N'-methylenebisacrylamide, N, N'-benzylidenebisacrylamide and the like. .

Examples of the acrylate having three or more acryloyl groups in the molecule include glycerin triacrylate,
Examples thereof include trimethylolpropane triacrylate, trimethylolethane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate.

Examples of the methacrylate having two or more methacryloyl groups in the molecule include methacrylates corresponding to the above acrylates.

At least one of the above acrylates and methacrylates is used, and both may be used as a mixture. In addition,
Monofunctional acrylates and methacrylates may be appropriately used in combination.

The amount of the addition-polymerizable compound is not particularly limited as long as the properties of the photopolymerizable composition are not impaired, but 10 to 200 parts by weight, preferably 20 to 100 parts by weight of the thermoplastic polymer.
~ 150 parts by weight.

As the photopolymerization initiator, various substances such as substituted or unsubstituted polynuclear quinones, aromatic ketones, benzoins, benzoin ethers, and substituted or unsubstituted thioxanthones can be used.

Examples of the substituted or unsubstituted polynuclear quinones include, for example, 2-
Methylanthraquinone, 2-ethylanthraquinone, 2
-Propylanthraquinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,4-dimethylanthraquinone, 2,3-dimethylanthraquinone, benz [a] anthraquinone, benz [b] anthraquinone, 2-phenylanthraquinone, 2,3- Diphenylanthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone, 3-chloro-2-methylanthraquinone, 1,4-naphthaquinone, 9,10-phenanthraquinone,
Examples thereof include 2-methyl-1,4-naphthaquinone, 2,3-dichloronaphthaquinone, and 7,8,9,10-tetrahydronaphthacenequinone.

As aromatic ketones, for example, benzophenone,
4,4'-bis (dimethylamino) benzophenone, 4,4 '
-Bis (diethylamino) benzophenone, 4-methoxy-4'-diethylaminobenzophenone and the like.

Examples of benzoins and benzoin ethers include benzoin, methyl benzoin, ethyl benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ethyl ether and the like.

Examples of the substituted or unsubstituted thioxanthone include thioxanthone, 2-chlorothioxanthone,
Methylthioxanthone, 2-ethylthioxanthone, 2
-Isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dibutylthioxanthone and the like.

Examples of other photopolymerization initiators include oxime esters such as benzyl, α, α-diethoxyacetophenone and benzophenone oxime acetate.

One or more of the above polymerization initiators are used, and the same or different photopolymerization initiators may be used in combination.

The amount of the photopolymerization initiator can be selected within a range that does not decrease the curing speed and the resolution, but usually, the thermoplastic polymer 10
The amount is 0.01 to 30 parts by weight, preferably 1 to 15 parts by weight based on 0 parts by weight.

The photopolymerization initiator is, for example, 2,4,5-triarylimidazolyl dimer, 2-mercaptobenzoxazole, leuco crystal violet, tris (4
-Diethylamino-2-methylphenyl) methane and aliphatic or aromatic tertiary amines such as N-methyldiethanolamine, ethyl p-dimethylaminobenzoate, and the like are useful.

The photopolymerizable composition of the present invention may contain a stabilizer, a coloring agent, a coloring agent for facilitating discrimination of a resist image, a plasticizer for imparting flexibility, if necessary, for suppressing a thermal polymerization reaction and for enhancing storage stability. And the like. As the stabilizer, for example, p
-Methoxyphenol, hydroquinone, hydroquinone monomethyl ether, tert-butylcatechol and the like are exemplified, and they are used in an appropriate amount as long as the photopolymerizability is not impaired. As the color former, a leuco compound of a triarylmethane dye is useful. For example, leuco crystal violet, leucomalachite green, mineral salts such as hydrochloride and sulfate of these leuco bodies, p-toluenesulfonate And the like. Also, as a coloring agent,
For example, crystal violet, malachite green, Victoria blue, methylene blue and the like are exemplified. Examples of the plasticizer include phthalic acid esters such as diethyl phthalate, dibutyl phthalate, diheptyl phthalate and dioctyl phthalate; fatty acid esters such as dioctyl adipate and dibutyl diglycol adipate; phosphoric acid esters such as totimethyl phosphine;
Examples thereof include sulfonic acid amides such as toluenesulfonic acid amide.

The photopolymerizable composition of the present invention may be a liquid containing no organic solvent, but is usually used in the form of a liquid or a dry film dissolved or dispersed in an organic solvent. Examples of the organic solvent include alcohols such as methanol, ethanol, and propanol; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as diethyl ether and tetrahydrofuran; and halogenated hydrocarbons such as methylene chloride. And the like. The dry film is produced, for example, by applying a polymerizable composition to a base film such as a polyethylene terephthalate film, drying the film, and then laminating a cover film such as a polyethylene film with a pressure roll or the like.

The photosensitive layer comprising the photopolymerizable composition of the present invention is usually printed or coated with a liquid photopolymerizable composition containing an organic solvent on a substrate such as a printed circuit board, and the organic solvent is removed or dried. It is formed by peeling the cover film of the film, and laminating the above-mentioned support with a rubber roll or the like.

The photosensitive layer is a light source that generates chemically active radiation,
For example, exposure is performed with a light source such as a low-pressure mercury lamp, an ultra-high-pressure mercury lamp, and a xenon lamp. Exposure is usually performed by providing a cover sheet on the photosensitive layer as necessary and using a negative or positive pattern mask by a contact method or a projection method. After exposure, development with an alkaline developer containing a basic compound yields a resist image corresponding to the pattern. As the basic compound of the alkali developer, for example,
Inorganic bases such as potassium carbonate, sodium carbonate, potassium bicarbonate, sodium bicarbonate, sodium silicate, sodium phosphate; organic bases such as butylamine, dimethylamine, trimethylamine, triethylamine, ethanolamine, diethanolamine, triethanolamine, morpholine, pyridine and the like Is exemplified. In the developer,
An organic solvent such as ethylene glycol monobutyl ether may be contained.

When a circuit pattern is formed, after forming a resist image, the resist image is treated with a plating solution or an etching solution, and the resist image is peeled off with a strong alkaline aqueous solution such as sodium hydroxide or an organic solvent such as methylene chloride. Is done.

(Examples and Comparative Examples) The present invention will be described in more detail based on examples. First, the following components were mixed to obtain a photopolymerizable resin composition.

Thermoplastic polymer 50 g Trimethylolpropane triacrylate 15 g Nonaethylene glycol dimethacrylate 10 g 2,4-Diethylthioxanthone 0.8 g Ethyl p-dimethylaminobenzoate 3 g Diamond green GH 0.03 g Methyl ethyl ketone 70 g Tetrahydrofuran 10 g Thermoplastic high The molecule has the composition shown in Table 1. The obtained photopolymerizable resin composition was laminated in a sandwich structure with a copper foil having a thickness of 0.1 mm, and the adhesion was measured by peeling 180 degrees. The measurement results are as shown in Table 1.

(Effects of the Invention) As is clear from the above results, the photopolymerizable resin composition according to the present invention not only gives a good resist pattern (resolution, sensitivity, minimum development time), but also significantly improves the adhesion to copper. Things.

Claims (1)

(57) [Claims] 1. A thermoplastic polymer having a polycaprolactone side chain comprising a copolymer compound of a polycaprolactone structure-containing monomer represented by the following formula (I) and a vinyl monomer represented by the following formula (II): A photopolymerizable composition containing a compound, a liquid or solid addition polymerizable compound at normal temperature and normal pressure, and a photopolymerization initiator. (However, N = 1 to 5, R _{1 to} R ₇ are a hydrogen atom or an alkyl group.) (However, R _{8 to} R ₁₁ represent a hydrogen atom, an alkyl group, an aromatic ring or a halogen atom or an alkyl ester group, or a carboxyl group.)