JP2001159815A - Photosensitive resin composition and photosensitive film using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition excellent in flexibility and resistance to the heat of soldering, developable with a dilute alkali solution and suitable for an etching resist and a cover lay and a photosensitive film using the composition. SOLUTION: The photosensitive resin composition developable with an aqueous alkali solution contains a carboxy-contatning urethane oligomer (A) obtained by reacting a polyol compound (a) with a polybasic acid anhydride (b) having two acid anhydride groups in one molecule, a polyisocyanate compound (c) and a (meth)acrylate (d) having one epoxy group in one molecule and a photopolymerization initiator (B).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive resin composition suitable for forming an etching resist or a protective film (coverlay) which can be used for manufacturing a flexible printed wiring board and the like, and a photosensitive film using the same.

[0002]

2. Description of the Related Art Conventionally, in the production of printed wiring boards, liquid or film-shaped photosensitive resin compositions have been used. For example, as a resist for etching a copper foil of a copper-clad laminate, a printed wiring board on which wiring is formed is used for specifying a soldering position, protecting the wiring, and the like.
2. Description of the Related Art Some printed wiring boards have a film shape that can be folded and incorporated into a small device such as a camera, and this is called an FPC. This FPC also requires a resist for specifying the soldering position and protecting the wiring, and is called a coverlay or a covercoat. The coverlay is formed by punching polyimide or polyester having an adhesive layer into a predetermined mold, and then by thermocompression bonding on an FPC. The cover coat is formed by printing and curing a thermosetting or photo-curing ink. Formed.

In these resists used for the purpose of specifying the soldering position of the FPC and protecting the wiring, flexibility is a particularly important characteristic, and therefore, a polyimide coverlay having excellent flexibility is often used. . However, this coverlay requires an expensive mold for die cutting,
In addition, due to the manual bonding of the die-cut film and the protrusion of the adhesive, the yield is low and the production cost is high, which is an obstacle to the expansion of the FPC market. It is difficult to respond to

Accordingly, a photosensitive resin composition for forming a highly accurate and highly reliable coverlay excellent in dimensional accuracy and resolution by a photographic development method (a method of forming an image by a phenomenon following image exposure), In particular, the appearance of a photosensitive film has been desired. For this purpose, attempts have been made to use a photosensitive resin composition for forming a solder mask. For example, photosensitive resin compositions containing an acrylic polymer and a photopolymerizable monomer as main components (JP-A-53-56018 and JP-A-54-56018).
As a photosensitive resin composition having good heat resistance, a composition mainly composed of a photosensitive epoxy resin having a chalcone group in a main chain and an epoxy resin curing agent (JP-A-54-82073) JP-A-58-62636), a composition mainly composed of a novolak-type epoxy acrylate containing an epoxy group and a photopolymerization initiator (JP-A-61-272, etc.), safety and economy As a photosensitive resin composition for forming a solder mask that can be developed with an alkaline aqueous solution, a carboxyl group-containing polymer,
Compositions comprising a monomer, a photopolymerization initiator and a thermosetting resin as main components (JP-A-48-73148, JP-A-57-73148)
178237, JP-A-58-42040,
JP-A-59-151152, etc.), but all have insufficient flexibility.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, and provides a photosensitive resin composition which is excellent in workability, excellent in flexibility, solder heat resistance and the like. To provide a photosensitive film.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, by using a photosensitive resin composition containing a specific carboxyl group-containing urethane oligomer (A). The inventors have found that the above-mentioned problems are solved and completed the present invention. That is, the present invention provides (1)
A polyol compound (a), a polybasic acid anhydride (b) having two acid anhydride groups in the molecule, a polyisocyanate compound (c), and one epoxy group in the molecule (meth)
Photosensitive resin composition containing carboxyl group-containing urethane oligomer (A) obtained by reacting acrylate (d), (2) (1) Carboxyl group-containing urethane oligomer (A) and photopolymerization initiator (B) And (3) a carboxyl group-containing urethane oligomer (A) having an acid value of 10 to 200 mgKOH /
g) the photosensitive resin composition according to (1) or (2),
(4) a photosensitive film obtained by laminating a layer of the photosensitive resin composition according to any one of (1) to (3) on a support film;
(5) A cured product of the photosensitive resin composition and the photosensitive film according to (1) to (4), and (6) an article having the cured product according to (5).

[0007]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail. The carboxyl group-containing urethane oligomer (A) used in the present invention comprises a polyol compound (a), a polybasic acid anhydride (b) having at least two acid anhydride groups in a molecule, and a polyisocyanate compound (c). It can be obtained by reacting (meth) acrylate (d) having one epoxy group in the molecule.

The polyol compound (a) includes, for example, polybutadiene polyol, phenolic polyol and / or flame-retardant polyol in addition to alkyl polyol, polyester polyol, polyether polyol and acrylic polyol.

Examples of the alkyl polyol include 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, cyclohexanedimethanol, trimethylolpropane, and pentaerythritol.

Examples of the polyester polyol include a condensation type polyester polyol, an addition polymerization polyester polyol, and a polycarbonate polyol. As the condensation type polyester polyol, ethylene glycol, propylene glycol, diethylene glycol,
1,4-butanediol, neopentyl glycol,
Diol compounds such as 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 1,4-hexanedimethanol, dimer acid diol, and polyethylene glycol, and adipic acid, isophthalic acid, and terephthalic acid It is obtained by a condensation reaction with an organic polybasic acid such as acid or sebacic acid, and has a molecular weight of 100 to 100,00.
0 is preferred.

The addition-polymerized polyester polyol includes polycafloractone, and has a molecular weight of 100 to 100.
100,000 is preferred. Polycarbonate polyol is synthesized by direct phosgenation of polyol, transesterification with diphenyl carbonate, and the like, and preferably has a molecular weight of 100 to 100,000.

[0012] As the polyether polyol, PEG
, PPG-based, and PTG-based polyols. P
The EG-based polyol is obtained by subjecting ethylene oxide to addition polymerization using a compound having active hydrogen as a reaction initiator, and preferably has a molecular weight of 100 to 100,000. PP
The G-based polyol is obtained by subjecting propylene oxide to addition polymerization using a compound having active hydrogen as a reaction initiator, and preferably has a molecular weight of 100 to 100,000. PT
The G-based polyol is synthesized by cationic polymerization of tetrahydrofuran, and preferably has a molecular weight of 100 to 100,000.

Examples of the polyether polyol other than the above polyether polyol include an ethylene oxide adduct or a propylene oxide adduct of bisphenol A, and the molecular weight is preferably 100 to 100,000.

Other polyols are copolymers of a (meth) acrylic acid ester containing a hydroxyl group and other (meth) acrylic acid esters (meth) acrylic polyols and copolymers of butadiene with a hydroxyl group at the terminal. A homo- or copolymer having a polybutadiene polyol, a silicon-modified polyol, a phenolic polyol containing a phenol molecule in the molecule,
Epoxy polyols, flame-retardant polyols containing a phosphorus atom, a halogen atom, etc., and the like, having a molecular weight of 100 to 1
00,000 is preferred. These polyol compounds,
They can be used alone or in combination of two or more.

The polybasic acid anhydride (b) having two acid anhydride groups in the molecule is preferably a carboxylic acid anhydride, for example, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, biphenyltetracarboxylic acid anhydride. Acid dianhydride, biphenyl ether tetracarboxylic dianhydride,
Examples thereof include diphenylsulfonetetracarboxylic dianhydride, butanetetracarboxylic dianhydride, ethylene glycol bis (anhydrotrimellitate) and the like, and these can be used alone or in combination of two or more.

Examples of the polyisocyanate compound (c) include 2,4- and / or 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), polymeric MDI, 1,5-naphthylene diisocyanate, Trizine diisocyanate,
1,6-hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, hydrogenated MDI, lysine diisocyanate, triphenylmethane triisocyanate, tris (isocyanatephenyl) thiophosphate and the like. Can be
These polyisocyanate compounds can be used alone or in combination of two or more.

The (meth) acrylate (d) having one epoxy group in the molecule includes, for example, glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate and the like. A mixture of more than one species can be used.

The carboxyl group-containing urethane oligomer (A) used in the present invention can be synthesized, for example, as follows. First, a polyol compound (a) and a polybasic acid anhydride having two acid anhydride groups in the molecule (b)
To prepare a carboxyl group-containing terminal hydroxyl group compound, and then react with the polyisocyanate compound (c) to obtain a carboxyl group-containing terminal hydroxyl group urethane prepolymer. Thereafter, a (meth) acrylate (d) having one epoxy group in the molecule is reacted.

The carboxyl group-containing terminal hydroxyl group compound is
Reaction of 0.5 to 0.98 equivalents (as acid anhydride equivalents) of polybasic acid anhydride (b) having two acid anhydride groups in the molecule per 1 equivalent of hydroxyl group of polyol compound (a) It is preferred that The reaction temperature of this esterification reaction is 60
The reaction time is preferably 1 to 10 hours. or,
As a reaction catalyst, a basic compound such as triethylamine may be added in an amount of 0.1 to 5% by weight based on the reaction substrate.

Next, the carboxyl group-containing terminal hydroxyl compound thus obtained is reacted with the polyisocyanate compound (c) to obtain a carboxyl group-containing terminal hydroxyl group urethane prepolymer. It is preferable to react 0.5 to 0.98 equivalent of isocyanate group of the polyisocyanate compound with respect to 1 equivalent of the hydroxyl group of the carboxyl group-containing terminal hydroxyl compound. The reaction temperature of the prepolymerization reaction is usually room temperature to 100 ° C, preferably 50 to 90 ° C. The reaction between these hydroxyl groups and isocyanate groups proceeds without a catalyst. For example, a catalyst such as triethylamine, dibutyltin laurate, dibutyltin diacetate or the like is used.
To 1000 ppm may be added.

Next, the carboxyl group-containing urethane prepolymer is preferably reacted with a (meth) acrylate (d) having one epoxy group in the molecule to obtain a carboxyl group-containing urethane oligomer (A).
Carboxyl group 1 of the terminal hydroxyl group-containing prepolymer
The epoxy group of (meth) acrylate (d) having one epoxy group in the molecule is 0.05 to 0.9 based on the equivalent weight.
Preferably, 5 equivalents are reacted, particularly preferably 0.1 equivalent.
It is 1 to 0.8 equivalent. The reaction temperature is usually from room temperature to 10
At 0 ° C, preferably 50-90 ° C. In order to prevent gelation due to radical polymerization during this reaction, usually 50 to 2
It is preferable to add 2,000 ppm of a polymerization inhibitor such as hydroquinone, hydroquinone monomethyl ether, p-methoxyphenol, and p-benzoquinone. Although the reaction between the carboxyl group and the epoxy group proceeds without a catalyst, a basic compound such as triethylamine or triphenylphosphine may be added as a catalyst.

At the time of this reaction, an organic solvent or a photopolymerizable monomer may be added. Specific examples of the organic solvent include aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate;
Ethers such as dioxane and tetrahydrofuran;
Ketones such as methyl ethyl ketone and methyl isobutyl ketone; glycol derivatives such as butyl cellosolve acetate, carbitol acetate, diethylene buryl dimethyl ether, propylene glycol monomethyl ether acetate; alicyclic hydrocarbons such as cyclohexanone and cyclohexane; petroleum ethers; petroleum naphtha; Petroleum solvents and the like can be mentioned. These organic solvents may be used alone or in combination of two or more.

Specific examples of the photopolymerizable monomers include carbitol (meth) acrylate, phanoxyethyl (meth) acrylate, acryloylmorpholine, bisphenol A polyethoxydi (meth) acrylate, polyethylene glycol di (meth) acrylate, Trimethylolpropane tri (meth) acrylate, pentaerythritol ditrimethylolpropanetetra (meth) acrylate, tris (2-hydroxyethyl) isocyanatetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like. One or two or more reactive monomers may be added.

The amount of the component (A) contained in the resin composition of the present invention is preferably from 10 to 100% by weight, particularly preferably from 20 to 100% by weight in the composition.

In the present invention, a diluent can be contained. Specific examples of diluents that can be used include organic solvents having no hydroxyl group and organic solvents having a hydroxyl group, such as methyl alcohol, ethyl alcohol, carbitol, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, and the like, or Photopolymerizable monomers having no hydroxyl group and photopolymerizable monomers having a hydroxyl group, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, cyclohexane-1,2-dimethylol mono ( (Meth) acrylate, glycerin di (meth)
Acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate and the like can be mentioned.

In the present invention, it is preferable to use a photopolymerization initiator (B). Examples of the photopolymerization initiator that can be used include benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin isobutyl ether; acetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 2-hydroxy-2-methyl-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone Acetophenones such as 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one; 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-chloroanthraquinone, Amyl anthraquinone Anthraquinones; 2,4-diethyl thioxanthone, 2-isopropylthioxanthone, thioxanthone such as 2-chlorothioxanthone; acetophenone dimethyl ketal,
Ketals such as benzyldimethyl ketal; benzophenones such as benzophenone, 4-benzoyl-4'-methyldiphenylsulfide and 4,4'-bismethylaminobenzophenone; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2 ,
And phosphine oxides such as 4,6-trimethylbenzoyl) -phenylphosphine oxide.

These can be used alone or as a mixture of two or more. Further, tertiary amines such as triethanolamine and methyldiethanolamine, ethyl N, N-dimethylaminobenzoate, N, N-dimethylaminobenzoate It can be used in combination with an accelerator such as a benzoic acid derivative such as acid isoamyl ester.

The amount of the photopolymerization initiator (B) used is (A) 1
1 to 30 parts by weight, preferably 5-2 to 100 parts by weight
The ratio is 0 parts by weight.

The photosensitive resin composition of the present invention is a mixture containing the above carboxyl group-containing urethane oligomer (A) and a photopolymerization initiator (B). The acid value (mgKOH / g) of the carboxyl group-containing urethane oligomer (A) used here is preferably from 10 to 200, particularly preferably from 30 to 150.

The photosensitive resin composition of the present invention may contain a thermoplastic polymer (C). For example, acrylic resin, polyester resin, vinyl acetate resin, vinyl chloride-vinyl acetate copolymer and the like can be mentioned. The thermoplastic polymer (C) includes a polymer having a carboxyl group and a polymer having no carboxyl group, and a polymer having a carboxyl group can be preferably used. More specifically, for example, acrylic acid, methacrylic acid, methyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, ethyl acrylate, methyl acrylate, styrene, α-methylstyrene, vinyl toluene, N-vinylpyrrolidone, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, acrylamide, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, acrylonitrile, methacrylonitrile, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, styrene / mailen A half ester of an acid copolymer is exemplified. These are used alone or in combination of two or more.

The weight average molecular weight of the component (C) is 5,000
It is preferably from 0 to 300,000. If the weight average molecular weight is less than 5,000, the film properties tend to decrease, and if it exceeds 300,000, the developability tends to decrease. Further, the carboxyl group content of the component (C) is preferably 0 to 50 mol%, more preferably 15 to 50 mol%. If it exceeds 50 mol%, pattern formation tends to be difficult. The component (C) is preferably soluble or swellable in an aqueous alkaline solution.

In the present invention, the component (C) is preferably 5 to 300% by weight, more preferably 10 to 250% by weight, based on the component (A).
It is preferred to use% by weight.

In the present invention, a thermosetting component (D) can be used. By using this, solder heat resistance and electrical characteristics can be further improved. Examples of the thermosetting component (D) that can be used include an epoxy resin, a melamine compound, an oxazoline compound, and a phenolic resin. As the epoxy resin, specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin,
Glycidyl ethers such as cresol / novolak type epoxy resin, trisphenol methane type epoxy resin, brominated epoxy resin and biphenol type epoxy resin;
3,4-epoxy-6-methylcyclohexylmethyl-
3,4-epoxy-6-methylcyclohexanecarboxylate, 3,4-epoxycyclohexylmethyl-
3,4-epoxycyclohexanecarboxylate, 1
Alicyclic epoxy resins such as epoxyethyl-3,4-epoxycyclohexane; glycidyl esters such as diglycidyl phthalate, diglycidyl tetrahydrophthalate and glycidyl dimer; glycidylamines such as tetraglycidyl diaminodiphenylmethane A heterocyclic epoxy resin such as triglycidyl isocyanurate; Among them, an epoxy resin having a melting point of 50 ° C. or more is preferable because a tack-free photopolymerizable film can be formed after drying.

Examples of the melamine compound include melamine and a melamine resin which is a polycondensate of melamine and formalin. Examples of the urea compound include urea and urea resins which are polycondensates of urea and formalin.

Examples of the oxazoline compound include 2-oxazoline, 2-methyl-2-oxazoline, 2-phenyl-2-oxazoline, 2,5-dimethyl-2-oxazoline, 5-methyl-2-phenyl-2-oxazoline,
2,4-diphenyloxazoline and the like.

Examples of the phenolic resin include phenol, cresol, chilenol, catechol, resorcin, hydroquinone, pyrogallol, resol and the like. Among these thermosetting components (D), epoxy resins are preferred because of their excellent reactivity with the carboxyl groups in the components (A) and (C) and excellent adhesion with copper. The thermosetting component (D) is (A),
It is preferable to use an amount such that the functional group in the thermosetting component (D) is 0.2 to 3 equivalents per one carboxyl group in the component (C). In particular, because it gives good hardening to solder heat resistance and electrical properties when it is made into a printed wiring board.
0-1.5 equivalents are preferred.

When an epoxy resin is used as the thermosetting component (D), it is preferable to use a curing accelerator. Specific examples of the curing accelerator for the epoxy resin include 2-methylimidazole and 2-methylimidazole. Imidazole compounds such as ethyl-3-methylimidazole, 2-undecylimidazole, 2-phenylimidazole, 1-cyanoethyl-2-ethylimidazole, 1-cyanoethyl-2-undecylimidazole, etc .; melamine, guanamine, acetoguanamine, benzoguanamine , Ethyldiaminotriazine, 2,4-diaminotriazine, 2,4
Triazine derivatives such as -diamino-6-tolyltriazine and 2,4-diamino-6-xylyltriazine; tertiary amines such as trimethylamine, triethanolamine, N, N-dimethyloctylamine, pyridine and m-aminophenol Polyphenols and the like.
These curing accelerators can be used alone or in combination.

In the present invention, various additives and the like can be further added as needed. As various additives,
For example, fillers such as talc, barium sulfate, calcium carbonate, magnesium carbonate, barium titanate, aluminum hydroxide, aluminum oxide, silica, clay,
Thixotropic agents such as Aerosil, phthalocyanine blue, phthalocyanine green, coloring agents such as titanium oxide, silicone, fluorine-based leveling agents and defoamers, dyes, hydroquinone, P-methoxyphenol,
And a polymerization inhibitor such as hydroquinone monotyl ether.

The photosensitive film of the present invention can be produced by laminating a layer of the photosensitive resin composition of the present invention on a support film. Examples of the support include a polymer film, for example, a film made of polyethylene terephthalate, polypropylene, polyethylene and the like. Among them, a polyethylene terephthalate film is preferable. Since these polymer films must be removed from the photosensitive layer later, they must not be surface-treated or made of a material that cannot be removed. The thickness of these polymer films is 5 to 10
The thickness is preferably 0 μm, more preferably 10 to 30 μm. These polymer films can be laminated on both sides of the photosensitive layer as a support film for one photosensitive layer and another as a protective film for the photosensitive layer.

The photosensitive resin composition of the present invention is obtained by dissolving and mixing the component (A) and, if necessary, the component (B), the component (C) and the diluent, the thermosetting component (D) or various additives. Can be prepared by kneading.

Next, the prepared resin composition is uniformly applied onto the support film (polymer film), and then the solvent is removed by heating and / or blowing with hot air.
By forming a dry film, a photosensitive film can be obtained. The thickness of the film after drying is not particularly limited, but is usually 10 to 100 μm, preferably 20 to 60 μm.

The photosensitive film of the present invention comprising two layers, the photosensitive layer and the polymer film, obtained as described above, may be used as it is or in the form of a roll by further laminating a protective film on the other surface of the photosensitive layer. It can be wound up and stored.

The photosensitive resin composition and the photosensitive film of the present invention are particularly useful as resists such as etching resists and solder resists for flexible printed wiring boards, and can also be used as paints, coating agents, adhesives and the like. .

As a method for producing a photoresist image using the photosensitive film of the present invention, when the protective film is present, the protective film is removed, and then the photosensitive layer is press-bonded to the substrate while heating. By doing so, they can be laminated. At this time, it is preferable that the layers are stacked under reduced pressure. The surface to be laminated is not particularly limited, and is preferably an FPC on which wiring is formed by etching or the like. The heating temperature of the photosensitive layer is not particularly limited,
The temperature is preferably set to 90 to 130 ° C. The pressure for pressing is not particularly limited, and it is preferable that the pressing be performed under reduced pressure.

The photosensitive layer thus completed in lamination is
It is imagewise exposed to active light using a negative film or a positive film.At this time, if the polymer film present on the photosensitive layer is transparent, it can be exposed as it is, but if it is opaque, Need to be removed. From the viewpoint of protecting the photosensitive layer, the polymer film is transparent, and it is preferable to expose the polymer film while leaving the polymer film remaining. As the active light, a known active light source can be used, and examples thereof include light generated from a carbon arc, a mercury vapor arc, a xenon arc, and the like.
Since the sensitivity of the photopolymerization initiator contained in the photosensitive layer is usually maximum in the ultraviolet region, the active antigen in that case preferably emits ultraviolet light effectively.

Next, after exposure, if a polymer film is present on the photosensitive layer, the polymer film is removed and then removed by a known method such as spraying, rocking immersion and brushing using an aqueous alkali solution. The unexposed portion can be removed and developed. Examples of the base of the alkaline aqueous solution include alkali hydroxides such as lithium, sodium or potassium hydroxide, alkali carbonates such as lithium or sodium or potassium carbonate or bicarbonate, potassium phosphate, and sodium phosphate. And alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate. Among them, an aqueous solution of sodium carbonate is preferable. The pH of the aqueous alkali solution used for development is preferably 9 to 11. The developing temperature can be adjusted according to the developability of the photosensitive layer. In the alkaline aqueous solution,
A surfactant, an antifoaming agent, and a small amount of an organic solvent for promoting development can be mixed.

Further, after the development, ultraviolet irradiation or heating by a high-pressure mercury lamp can be performed for the purpose of improving solder heat resistance, chemical resistance and the like as a coverlay of the FPC. The irradiation amount of ultraviolet rays is 0.2 to 10 J / cm 2
It is preferable that at the time of this irradiation, 60 to 150
It is preferably accompanied by heat of ° C. The heating temperature during heating is preferably 100 to 170 ° C. Either the irradiation of the ultraviolet rays or the heating may be performed first. After the characteristics of the coverlay are given in this way,
It is mounted (soldered) on components such as LSIs and mounted on articles such as devices such as cameras.

The photosensitive resin composition of the present invention provides a photosensitive film or a cured film excellent in photosensitivity, alkali developability, flexibility, soldering heat resistance and the like.
It is suitable for an etching resist for C and a photosensitive film for coverlay.

[0049]

The present invention will be described in more detail with reference to the following examples. It goes without saying that the present invention is not limited to the following examples.

Synthesis Example 1 (Synthesis example of carboxyl group-containing urethane oligomer (A)) Polytetramethylene glycol (hydroxyl value: 129 mg)
870 g of KOH / g, molecular weight: 870), 109 g of pyromellitic anhydride (acid value: 1011 mg KOH / g), and 729 g of methyl isobutyl ketone were charged.
The reaction was carried out for 0 hour to obtain a carboxyl group-containing terminal hydroxyl group compound (acid value of solid content: 56 mgKOH / g). Next, 58.1 g of tolylene diisocyanate was charged, and about 15% at 85 ° C. until the isocyanate group concentration became 0.3%.
The reaction was carried out for a period of time to obtain a urethane prepolymer having a carboxyl group-containing terminal hydroxyl group (acid value of solid content: 53 mgKOH / g). Next, 56.4 g of glycidyl methacrylate and 1.75 g of p-methoxyphenol were charged and reacted at 95 ° C. for 10 hours, and the acid value of the solid was 35.5 mgKOH /
g, a carboxyl group-containing urethane oligomer (A-1) having a weight average molecular weight of about 14000 (by GPC method) and a solid content of 60% was obtained.

Synthesis Example 2 (Synthesis Example of Thermoplastic Polymer (C) Having Carboxyl Group) Methyl cellosolve / toluene = 12 of a 3/2 solution by weight
1.5 g was put in a flask, heated to 85 ° C., and left for 1 hour. Next, 13.5 g of methacrylic acid, 46.8 g of methyl methacrylate, 38.2 g of ethyl acrylate,
A solution of 3.2 g of 2-hydroxyethyl methacrylate, 1.5 g of 2-ethylhexyl acrylate, 0.17 g of azobisisobutyronitrile, 18.7 g of methylcellosolve and 12.5 g of toluene was allowed to react dropwise over 4 hours. . Thereafter, 7.1 g of methyl cellosolve was added, and the mixture was kept for 2 hours. A solution of 0.6 g of methacrylic acid, 0.54 g of azobisisobutyronitrile, 2.9 g of methyl cellosolve, and 1.9 g of toluene was added, and the mixture was kept for 2 hours. . Thereafter, a solution prepared by dissolving 0.024 g of azobisisobutyronitrile in 1.2 g of methyl cellosolve was added, and the mixture was kept warm for 5 hours. After adding 0.01 g of hydroquinone, the mixture was cooled, and the average molecular weight was 84,000 and the nonvolatile content was 38.5% by weight. A thermoplastic polymer (C-1) having a carboxyl group having a solid content acid value (mgKOH / g) of 85 was obtained.

EXAMPLES AND COMPARATIVE EXAMPLES A photosensitive resin composition containing the materials shown in Table 1 was 25 μm
The film was uniformly coated on a polyethylene terephthalate film having a thickness of 5 mm and dried to remove the solvent. The thickness of the photosensitive layer after drying was 50 μm. Next, a polyethylene film was laminated as a protective film on the photosensitive layer to obtain a photosensitive laminate.

Table 1 Amount (parts by weight) Material Example 1 Example 2 Example 3 Comparative Example A-1 75.0 90.0 158.3 C-1 105.3 85.3 250.3 DPCA-60 * 1 20.0 20.0 20.0 20.0 EAB * 2 0.1 0.1 0.1 0.1 Benzophenone 5.0 5.0 5.0 5.0 Melamine 10.0 10.0 10 0.0 10.0 MEK 115.0 120.0 137.0 45.0

Note) * 1: DPCA-60; KAYAR manufactured by Nippon Kayaku Co., Ltd.
AD DPCA-60 (ε- of dipentaerythritol
Polyacrylate of caprolactone adduct * 2: EAB; 4,4'-diethylaminobenzophenone manufactured by Hodogaya Chemical Co., Ltd.

Separately, the copper surface of an FPC substrate (trade name, F30VC125RC11, manufactured by Nikkan Kogyo Co., Ltd.) in which a 35 μm thick copper foil was laminated on a polyimide substrate was polished with an abrasive brush, washed with water, and dried. The photosensitive film was laminated on this substrate (23 ° C.) using a vacuum laminator.

Next, the obtained sample was added
Exposure was performed at 200 mJ / cm2 using a one-step tablet and a negative film of a linear line having a line / space of 150 μm / 150 μm, and then left at room temperature for 30 minutes. Next, spray development was performed at 30 ° C. for 100 seconds using a 1% aqueous solution of sodium carbonate. Here, the number of remaining step tablets is measured, and the results are shown in Table 2.
It was shown to. Next, a heat treatment was performed at 150 ° C. for 45 minutes, and further, ultraviolet irradiation at ³ J / cm ² was performed to obtain a coverlay.

This sample was heated at 180 ° C. for evaluation of flexibility.
After bending, coverlay was observed for cracks and other abnormalities. Then, rosin crack MH-820V
(Trade name, manufactured by Tamura Kaken Co., Ltd.), soldered at 260 ° C. for 10 seconds, observed for abnormalities such as blistering as solder heat resistance, and then evaluated for flexibility. Therefore, the coverlay was bent at 180 ° C., and the coverlay was observed for cracks and other abnormalities. Table 2 shows the above evaluation results.

Table 2 Number of remaining steps Solder heat resistance Bendability (180 ° C.) (260 ° C., 10 seconds) Before soldering After soldering Example 1 9 Good Good Good Example 2 9 Good Good Good Good Example 3 9 Good Good Good Comparative Example 2 8 Good Cracking Cracking

As is clear from Table 2, when the photosensitive resin composition of the present invention was used, a coverlay having good solder heat resistance and bending property (flexibility) was obtained.

[0060]

The photosensitive resin composition of the present invention has a
It provides a film or a cured film having excellent alkali developability, flexibility and soldering heat resistance, and therefore has good workability and is suitable for an FPC etching resist and a coverlay photosensitive film.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2H025 AA09 AA10 AA13 AB11 AB15 AB20 AC01 AD01 BC31 BC66 BC83 BC85 BC86 FA17 FA39 FA43 5E314 AA27 AA32 CC15 FF06 FF19 GG10 5E339 AA02 BE11 CC01 CC02 CC10 CD01 CE12 CE16 CF16 CF17 DD

Claims (6)

[Claims] 1. A polyol compound (a), a polybasic acid anhydride (b) having two acid anhydride groups in a molecule, a polyisocyanate compound (c) and one epoxy group in a molecule ( A photosensitive resin composition containing a carboxyl group-containing urethane oligomer (A) obtained by reacting a (meth) acrylate (d). 2. A photosensitive resin composition comprising the carboxyl group-containing urethane oligomer (A) according to claim 1 and a photopolymerization initiator (B). 3. The photosensitive resin composition according to claim 1, wherein the carboxyl group-containing urethane oligomer (A) has an acid value of 10 to 200 mgKOH / g. 4. A photosensitive film obtained by laminating a layer of the photosensitive resin composition according to claim 1 on a support film. 5. A cured product of the photosensitive resin composition and the photosensitive film according to claim 1. 6. An article having the cured product according to claim 5.