JP2661744B2 - Photosensitive resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a photosensitive resin composition, and more particularly, to a photosensitive resin composition which can be dissolved in an aqueous alkali solution and is used for manufacturing printed wiring boards and the like. About.

(Prior Art) For example, in manufacturing a printed wiring board, a photosensitive solution in which a photosensitive resin composition is dissolved is applied on a copper-clad laminate, and then heated and dried to form a photosensitive layer on the copper-clad laminate. Then, a photoresist image is formed by exposing the photosensitive layer from above a negative film.

However, in the method of forming a photosensitive layer using a photosensitive solution as described above, the workability is poor, and there is a problem that the solvent is contaminated during drying. Therefore, in recent years, a support film layer, a photosensitive layer, and a protective film have been used. Film-shaped photoresists having a three-layer structure have been used.
In addition, this film-shaped photoresist is classified into two types, a solvent development type and an alkali development type, depending on the type of the developing solution.
Since an organic solvent is used during development, the above problem has not been solved. Recently, alkali-developing film-type photoresists have been mainly used (see, for example, JP-A-58-1142).

To manufacture a printed wiring board using an alkali-developable film-like photoresist, first, the protective film is removed, and a laminated film composed of a photosensitive layer and a support film layer is formed. The laminated film is heat-pressed and laminated on the copper-clad laminate so as to be in contact with the plate. Next, after exposing the wiring pattern to the laminated film using a negative film, the supporting film is peeled off, and the unexposed portion of the photosensitive layer is removed (developed) using an aqueous solution of sodium carbonate to form a resist image. Next, the surface of the copper-clad laminate on which the resist image has been formed is subjected to a treatment by etching or plating, and then the resist image is peeled off using an alkaline aqueous solution stronger than a developing solution to produce a printed wiring board.

(Problems to be Solved by the Invention) When a conventional photosensitive resin composition is used as a photosensitive layer material at the time of manufacturing a printed wiring board, the following two problems are raised.

After the exposure, the hardened resist protruding from the end face of the copper-clad laminate is hard and brittle, so that its fragments scatter around, and these fragments get on between circuit lines and cause a short circuit.

If the copper-clad laminate hits any protrusions during the manufacture of the printed wiring board described above, the hardened resist is hard and brittle and easily breaks, resulting in disconnection.

For these reasons, the yield has been significantly reduced in the manufacturing process of the printed wiring board.

The present invention solves the above-mentioned drawbacks, and an object of the present invention is to provide a photosensitive resin composition in which the hardened portion of the resist by the actinic light is tough and flexible, and the yield is significantly improved in the process of manufacturing a printed wiring board. To provide things.

(Means for Solving the Problems) The linear copolymer (a) used in the present invention comprises α, β-
It is a copolymer of an unsaturated ethylene monomer and a carboxyl group-containing monomer.

Examples of the α, β-unsaturated ethylenic monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, styrenes such as pn-hexylstyrene, pn-octylstyrene, p-methoxystyrene, p-phenylstyrene, and 3,4-dimethylchlorostyrene; vinylnaphthalenes such as α-vinylnaphthalene; ethylene and propylene , butylene or C ₅ -C ₃₀ and more α- olefins, vinyl chloride, vinyl bromide, vinyl halides such as vinyl fluoride, vinyl acetate, vinyl propionate, vinyl esters such as vinyl acetate; ( Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate,
N-butyl (meth) acrylate, isobutyl (meth) acrylate, n-octyl (meth) acrylate, (meth)
Lauryl acrylate, 2-ethylhexyl (meth) acrylate, 2-chloroethyl (meth) acrylate, methyl α-chloro (meth) acrylate, phenyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, etc. (Meth) acrylic acid esters; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone and vinyl ethyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-
And N-vinyl compounds such as vinyl indole.

The carboxyl group-containing monomer may be any monomer containing a carboxyl group and copolymerizable with the α, β-unsaturated ethylenic monomer, such as (meth) acrylic acid, Crotonic acid, fumaric acid, cinnamic acid, itaconic acid, maleic acid (anhydride) and the like.

When the amount of the carboxyl group-containing monomer in the linear copolymer (a) decreases, the monomer becomes insoluble in an aqueous alkali solution and cannot be developed with an aqueous alkali solution, and when the amount increases, the resolution deteriorates. %, Preferably 15 to 35% by weight.

Further, when the weight average molecular weight of the polymer (a) is small, cold flow is likely to occur, and when the weight average molecular weight is large, it is difficult to dissolve in an aqueous alkali solution and developability and resolution are reduced. , Preferably 5
10,000 to 300,000.

In the urethane oligomer (meth) acrylate (b) used in the present invention, the terminal hydroxyl group of the urethane oligomer which is a reaction product of isophorone diisocyanate and the diol represented by the general formula (I) is modified with (meth) acrylic acid. It is a thing.

HOCH ₂ CH _{2 On} H ( _n ) (wherein n is an integer of 2 to 20) The urethane oligomer (meth) acrylate (b)
When the weight average molecular weight of the exposure is reduced, the flexibility of the resin composition layer after exposure is reduced, and the development time is increased when the weight is increased, the 1,000 to 15,000 is preferable, more preferably 3,0
It is 100 to 10,000.

Also, urethane oligomer (meth) acrylate (b)
When the amount of addition is small, the flexibility of the resin composition layer after exposure and development is reduced, and when it is large, the edge fusion is likely to occur and the development time is long. 10 to 40 parts by weight.

Also, urethane oligomer (meth) acrylate (b)
Any method may be adopted as the production method, for example, isophorone diisocyanate and diol are mixed and reacted in substantially equimolar amounts to form a urethane oligomer, and then acrylic acid or methacrylic acid is added to react with terminal hydroxyl groups. Just do it. At this time, if necessary, isophorone diisocyanate and diol may be dissolved in an organic solvent such as ethyl acetate, methyl ethyl ketone, and toluene to cause a reaction, and a catalyst such as dibutyltin dilaurate may be added.

The addition polymerizable substance (c) used in the present invention is a compound represented by the general formula (II), In the formula, R ¹ and R ² represent hydrogen or a methyl group, and m is 4 to 12
Indicates an integer. The number of n is limited to 4 to 12, since the smaller the number, the lower the flexibility of the exposed resin composition layer, and the larger the number, the longer the development time.

When the addition amount of the addition polymerizable substance (c) is small, the development time is prolonged, and when the addition amount is large, edge fusion is easily caused. Therefore, the addition amount is 5 to 80 parts by weight, preferably 10 to 50 parts by weight.

The photopolymerization initiator (d) used in the present invention is not particularly limited as long as it has a property of activating the above-mentioned addition-polymerizable substance or the like by actinic rays such as ultraviolet rays and visible rays and initiating polymerization. For example, for activation,
Sulfides such as sodium methyldithiocarbamate sulfide, tetramethyltium monosulfide, diphenyl monosulfide, dibenzothiazoyl monosulfide and sulfide; thioxanthon, 2-
Ethylthioxanthone, 2-chlorothioxanthone, 2,
Thioxanthone derivatives such as 4-diethylthioxanthone; (di) azo compounds such as hydrazone, azoisobutyronitrile, benzenediazonium chloride; benzoin, benzoin methyl ether, benzoin ethyl ether, benzophenone, dimethylaminobenzophenone, Michler's ketone, benzylanthraquinone, t -Butylanthraquinone, 2-methylanthraquinone, 2-
Ethylanthraquinone, 2-aminoanthraquinone, 2
-Aromatic carbonyl compounds such as chloroanthraquinone; p
-Methyl dimethylaminobenzoate, ethyl p-dimethylaminobenzoate, butyl p-dimethylaminobenzoate,
dialkylaminobenzoic acid esters such as isopropyl p-diethylaminobenzoate; peroxides such as benzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide, cumene hydroperoxide; 9-phenylacridine, 9-p- Acridine derivatives such as methoxyphenyl acridine, 9-acetylamino acridine, benzacridine; phenazine derivatives 6,4 ', 4 "-such as 9,10-dimethylbenzphenazine, 9-methylbenzphenazine, 10-methoxybenzphenazine;
Quinoxaline derivatives such as trimethoxy-2,3-diphenylquinoxaline; 2,4,5-triphenylimidazolyl dimer and the like; and those activated with visible light include, for example, 2-nitrofluorene, 2,4 , 6-Triphenylpyrylium tetrafluoroboron salt, 2,4,6-tris (trichloromethyl) -1,3,5-triazine, 3,3'-carbonylbiscoumarin, thiomichler ketone, etc. .

And the photopolymerization initiator comprises the copolymer (a)
0.1 to 10 parts by weight is added to 100 parts by weight.

The photosensitive resin composition of the present invention comprises the above-mentioned copolymer (a), urethane oligomer (meth) acrylate (b), addition polymerizable substance (c) and photopolymerization initiator (d). A photopolymerizable monomer (e) which is liquid at room temperature and can be cured by initiating a polymerization reaction by actinic rays may be added. Examples of the monomer include triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and tripropylene glycol di (meth) acrylate. ) Acrylate, pentaerythritol (meth)
Acrylate, dipentaerythritol penta (meth)
Acrylate, dipentaerythritol hexa (meth)
Acrylate, trimethylolpropane tri (meth) acrylate, 2,2 bis [4 (acryloxydiethoxy)
Phenyl] propane, 2,2 bis [4- (methacryloxydiethoxy) phenyl] propane, 3-phenoxy-2-
Examples include propanoyl acrylate, polymethylene di (meth) acrylate, 1,6-bis (3-acryloxy-2-hydroxypropyl) -hexyl ether, and urethane polyester acrylate oligomer.

The photopolymerizable monomer (e) is preferably added in an amount of 5 to 150 parts by weight, more preferably 10 to 100 parts by weight, based on 100 parts by weight of the polymer (a). If the amount of the photopolymerizable monomer (e) is small, curing after exposure is likely to be insufficient. If the amount is large, the tackiness of the unexposed portion is increased and a good image is hardly obtained.

If necessary, a coloring agent such as malachite green or ethyl violet, a plasticizer such as dioctyl phthalate or triethylene glycol diacetate, or a polymerization inhibitor such as hydroquinone or p-methoxyphenol may be added.

The photosensitive resin composition of the present invention is usually dissolved in a solvent such as methyl ethyl ketone, acetone, methanol, isopropanol, ethyl cellosolve, or methylene chloride, and applied to a support film such as a polyethylene terephthalate film and dried to form a photosensitive resin. A layer of the composition is formed and becomes a dry film resist (DFR).

This DFR can be used for forming a photoresist image and a relief image in the same manner as the conventional product.

(Example) Next, an example of the present invention will be described.

Examples 1 to 3, Comparative Examples A predetermined amount of the linear copolymer, urethane oligomer acrylate, addition polymerizable substance, photopolymerization initiator and the like shown in Table 1 were dissolved in 400 parts of methyl ethyl ketone, and a photosensitive resin composition was obtained. Was prepared. This solution was applied on a support film made of a polyethylene terephthalate film having a thickness of 20 μm, and dried at 80 ° C. for 10 minutes to obtain a 50 μm thick film.
m of the photosensitive resin composition layer was formed to prepare DFR.

The obtained DFR is applied to the surface of a glass epoxy double-sided copper-clad laminate (copper thickness 50 μm) whose surface has been degreased and polished at 60 ° C for 10
After preheating for one minute, thermocompression bonding was performed at a pressure of 2.0 kg / cm ^{2 and a} speed of 1.5 m / min.

The obtained laminate was passed through a resolution pattern and a 21-step stofa step tablet, and was fed with a 3 kw high-pressure mercury lamp to 100 mJ / cm ^2.
Exposure.

Subsequently, the support film was peeled off at room temperature, and spray-developed with a 1% by weight aqueous sodium carbonate solution at 30 ° C. under a pressure of 1.0 kg / cm ² to measure the resolution and sensitivity. In addition, the obtained DFR was cut to obtain a 10 × 100 mm sample, and 80 mJ /
After exposure to cm ² , the support film was peeled off, pulled at a speed of 100 mm / min, and the elongation to break was measured.

The support film of the sample exposed in the same manner was peeled off, immersed in a 1% by weight aqueous solution of sodium carbonate for 90 seconds and developed, and the elongation to break was measured.

The obtained DFR was rolled into a 120 m roll, stored at 35 ° C., and the time required for the photosensitive resin composition to ooze from the end of the roll was measured. (Storage stability) (Effect of the Invention) Since the photosensitive resin composition of the present invention has the above-described configuration, for example, when this photosensitive resin composition is used as a circuit forming material, the photocured portion is tough. In addition, disconnection and short circuit during the circuit forming process can be reduced, and as a result, tenting resistance can be improved, and the yield can be significantly improved. Therefore, the photosensitive resin composition of the present invention is particularly effectively used for manufacturing a printed wiring board requiring high density and high precision.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location G03F 7/027 502 G03F 7/027 502 513 513 7/032 7/032

Claims (1)

(57) [Claims] (1) (a) α, β-unsaturated ethylenic monomer 60
A copolymer having a weight-average molecular weight of 20,000 to 500,000, and a copolymer of 100 to 90% by weight and a carboxyl group-containing monomer 10 to 40% by weight; wherein terminal hydroxyl group of the urethane oligomer is the reaction product of a diol represented by the formula (I) is (meth) urethane oligomer comprising modified with acrylic acid (meth) acrylate 5-50 parts by HOCH ₂ CH ₂ O _n H ... ... (I) (wherein n represents an integer of 2 to 20) (c) 5 to 80 parts by weight of an addition polymerizable substance represented by the general formula (II) (Wherein, R ¹ and R ² represent hydrogen or a methyl group, and m is 4 to
Indicates an integer of 12. (D) a photosensitive resin composition comprising 0.1 to 10 parts by weight of a photopolymerization initiator sensitized by actinic rays