JPH077208B2 - Dry film photoresist - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to dry film photoresists. More specifically, the present invention relates to a dry film photoresist having excellent developability and film peeling property with an alkaline aqueous solution and excellent strength of a tent film.

"Prior Art" A method of using a dry film photoresist (hereinafter referred to as DFR) is known as one of methods for forming a printed circuit board. This DFR is described in JP-B-45-25231, and more detailed usage is described in, for example, WSDe.
Forest “Photoresist” Mc Grew-Hill New York (19
75) 163-212.

The main purpose of DFR is to protect through holes by the tenting method. In this method, the through hole portion is covered with a photocured photosensitive resin composition layer, a so-called tent film, in the development and etching steps. It is extremely important that the tent film is free from defects such as film breakage and floating during the development and etching processes. However, in these steps, since the developing solution, the etching solution, etc. are sprayed at a high pressure, the tent film is often broken in the conventional DFR, and the mechanical properties are such that such defects do not occur. Development of DFR was required.

This DFR includes those using an organic solvent for development and peeling, and those using an alkaline aqueous solution, but in recent years, a shift to using an alkaline aqueous solution has been made in view of environmental hygiene and explosion proof. However, when an alkaline aqueous solution is used, there is a problem that the tent film is more likely to break than when an organic solvent is used.

By the way, DFR generally contains a polymer binder, an addition-polymerizable unsaturated compound (hereinafter referred to as a monomer), and a photopolymerization initiator as essential components. Among these, the polymer binder and the monomer have an influence on the above-mentioned mechanical properties, but the influence of the monomer is particularly dominant, and various monomers have been conventionally proposed.

Specific examples of the monomers used for DFR include acrylic acid or methacrylic acid esters of polyols, that is, ethylene glycol di (meth) acrylate, diethyl glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene. Glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, dodecaethylene glycol di (meth) acrylate, tetradecaethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) Acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipen Hexa (meth) acrylate, 1,6-hexanediol di (meth)
Acrylates and the like, or acrylamides or methacrylamides obtained from polyamines, that is, methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide, m-xylylenebis (meth) acrylamide, etc., or compounds containing a urethane group, that is, di- (2 -Methacryloxyethyl) -2,4-tolylenediurethane, di- (2-acryloxyethyl) hexamethylenediurethane, or a terminal isocyanate compound obtained by previously reacting a polyol and a diisocyanate with β-hydroxyalkyl A (meth) acrylic urethane oligomer obtained by reacting a (meth) acrylate, for example, a reaction product of 4 moles of 2,4-tolylene diisocyanate and 3 moles of ethylene glycol with 1 mole of β- Oligomer or the like obtained by reacting hydroxyethyl acrylate, or acrylic acid or methacrylic acid ester modified and induced from bisphenol A, that is, a reaction product of bisphenol A-epichlorohydrin type epoxy resin prepolymer and acrylic acid or methacrylic acid, Acrylic acid or methacrylic acid esters of alkylene oxide adducts of bisphenol A or hydrogenated products thereof, or esters of aromatic polyvalent carboxylic acids, that is, compounds represented by the following structural formulas (II) to (IV) Can be mentioned.

Further, a dry film photoresist using a monomer containing a urethane group is disclosed in JP-B-56-17654 (alkali developing type), JP-A-59-204837, JP-A-61-77844 and the like.

However, when these monomers are used, the strength of the tent film is insufficient, or when an organic solvent is used for development, the tent film has sufficient strength, but when an alkaline aqueous solution is used, Is the film strength insufficient,
Alternatively, although the tent membrane has sufficient strength, other performance required for use as a DFR is insufficient, that is,
As a result of improving the developing solution resistance and the etching solution resistance, there has been a big defect that the developing property and particularly the film peeling property are lowered.

As described above, in a DFR in which development and film peeling are performed with an alkaline aqueous solution, it is very difficult to obtain a DFR in which the strength of the tent film is sufficient and which is excellent in developability and film peeling property.

"Problems to be Solved by the Present Invention" Therefore, an object of the present invention is to provide a dry film photoresist which is free from tearing of the tent film in the development and etching steps, and has good developability and peeling property. Is. Further, it is an object of the present invention to provide a dry film photoresist which has an excellent resist shape after development, has a high resolution, and gives a resist which can sufficiently withstand use in a plating process.

“Means for Solving Problems” The present inventors have conducted various studies, and as a result, have found that the above object can be achieved by a dry film photoresist using a photosensitive resin composition containing a specific monomer. The present invention has been reached.

That is, an object of the present invention is to provide a dry film photoresist comprising at least a flexible film support and a photosensitive resin composition layer, wherein the photosensitive resin composition layer is an essential component (A) against an alkaline aqueous solution. Soluble or swellable polymer binder (B) Monomer represented by the following general formula (I) (In the formula, R is a hydrogen atom or a methyl group, X is a divalent organic group containing an aromatic ring, and n is an integer of 2 to 20.) (C) A photopolymerization initiator is contained. Achieved with a dry film photoresist.

The compound of the general formula (I) used in the present invention can be obtained by addition reaction of 1 mol of an aromatic ring-containing diisocyanate and 2 mol of polyethylene glycol mono (meth) acrylate according to a conventional method.

Specific examples of the diisocyanate containing an aromatic ring include m-
Phenylene diisocyanate, p-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate,
1,5-naphthylene diisocyanate, 1,4-mesitylene diisocyanate, 4,4'-biphenylene diisocyanate, 4,4'-diisocyanate diphenylmethane and the like can be mentioned. These diisocyanate compounds may be used alone or in combination of two or more.

Specific examples of polyethylene glycol monoacrylate or polyethylene glycol monomethacrylate include diethylene glycol mono (meth) acrylate,
Triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate, pentaethylene glycol mono (meth) acrylate, hexaethylene glycol mono (meth) acrylate, heptaethylene glycol mono (meth) acrylate, octaethylene glycol mono (( (Meth) acrylate, nonaethylene glycol mono (meth) acrylate, decaethylene glycol mono (meth) acrylate, undecaethylene glycol mono (meth) acrylate, dodecaethylene glycol mono (meth) acrylate, tridecaethylene glycol mono (meth) acrylate , Tetradeca ethylene glycol mono (meth) acrylate, pentadeca ethylene glycol mono (meth) acrylate, hexadeca Tylene glycol mono (meth) acrylate, heptadecaethylene glycol mono (meth) acrylate, octadecaethylene glycol mono (meth) acrylate, nonadecaethylene glycol mono (meth) acrylate, eicosa ethylene glycol mono (meth) acrylate and the like. And a mixture of two or more thereof. As a particularly preferred specific example, the repeating number of ethylene glycol is 2 to 40.
And a monoacrylate or a monomethacrylate of a mixture having a repeating number of 3 to 20 as an average value, for example, as a blender PE-200, PE-350 commercially available from NOF Corporation, etc. Available.

The compound of the general formula (I) of the present invention may be used alone, but for various purposes, addition polymerization containing one or more other polyfunctional monomer or one ethylenically unsaturated double bond in the molecule. It can also be used as a mixture with a polyunsaturated compound (monofunctional monomer).

Specific examples of the polyfunctional monomer include acrylic acid or methacrylic acid esters of polyols, acrylamides or methacrylamides obtained from polyamines, urethane group-containing compounds, and polyols and diisocyanates previously reacted. (Meth) acrylic urethane oligomer obtained by further reacting the obtained terminal isocyanate compound with β-hydroxyalkyl (meth) acrylate, acrylic acid or methacrylic acid ester modified and derived from bisphenol A, structural formula (II) to Examples thereof include compounds represented by (IV).

Specific examples of the monofunctional monomer include tetraethylene glycol monophenyl ether acrylate, tetraethylene glycol mono p-nonylphenyl ether acrylate, tetrapropylene glycol mono p-nonylphenyl ether acrylate, and 2-hydroxy-3.
Mention may be made of phenoxypropyl acrylate, phthalic acid monoacryloxyethyl ester, succinic acid monoacryloxyethyl ester.

The content of the monomer is preferably about 7.5 to 55% by weight, more preferably about 15% by weight based on the total weight of the photosensitive resin composition.
~ 45% by weight.

The polymer binder preferably used in the photosensitive resin composition used for the dry film photoresist of the present invention may be one that is soluble or swellable in an alkaline aqueous solution. Specific examples of such a polymer binder include a methyl methacrylate / methacrylic acid copolymer disclosed in JP-B-46-32714, and JP-B-55-3896.
No. 1 styrene / maleic acid mono-n-butyl ester copolymer disclosed in JP-B No. 56-33413. Ethyl methacrylate / ethyl acrylate / methacrylic acid terpolymer disclosed in JP-B No. 56-33413. Methyl methacrylate / methacrylic acid / acrylic acid 2-disclosed in 58-1142
Ethylhexyl terpolymer or methacrylic acid / methyl methacrylate / 2-ethylhexyl acrylate / n-butyl methacrylate terpolymer, Japanese Patent Application No. 61-295441
And the methacrylic acid / methyl methacrylate / 2-ethylhexyl acrylate / benzyl methacrylate quaternary copolymers disclosed in the above publication.

The content of these polymeric binders is preferably about 40 to 80% by weight, more preferably about 50 to 70% by weight, based on the total weight of the photosensitive resin composition.

As the photopolymerization initiator preferably used in the photosensitive resin composition used for the dry film photoresist of the present invention, a single compound capable of initiating the polymerization of the polymerizable unsaturated compound described above, or two or more kinds All photoinitiator systems that combine compounds can be used. Preferably, the photoinitiator or photoinitiator system is about 3000-80.
00A, preferably at least about 50 within the range of 3300-5000A.
It contains at least one component having a molecular extinction coefficient of.

The following compounds may be mentioned as preferred specific examples of the photopolymerization initiator. Aromatic ketones such as benzophenone, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone,
4-methoxy-4'-dimethylaminobenzophenone,
4,4'-dimethoxybenzophenone, 4-dimethylaminobenzophenone, 4-dimethylaminoacetophenone, benzyl, anthraquinone, 2-tert-butylanthraquinone, 2-methylanthraquinone, phenanthraquinone, xanthone, thioxanthone, 2-chloro-thioxanthone , 2,4-diethylthioxanthone, fluorenone, acridone, etc., benzoin or benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin phenyl ether, etc., 2,4,5-triarylimidazole Dimers such as 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl)
-4,5-di (m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl)-
4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer and the like, polyhalogen compounds such as carbon tetrabromide, phenyltribromomethyl sulfone, phenyltrichloromethyl ketone Etc., such as coumarins, for example, 3- (2-benzofuroyl) -7-diethylaminocoumarin, 3- (2-benzofuroyl) -7- (1-pyrrolidinyl) coumarin, 3-
Benzoyl-7-diethylaminocoumarin, 3- (o-
Methoxybenzoyl) -7-diethylaminocoumarin,
3- (p-dimethylaminobenzoyl) -7-diethylaminocoumarin, 3,3'-carbonylbis (5,7-di-n
-Propoxycoumarin), 3.3'-carbonylbis (7
-Diethylaminocoumarin), 3-benzoyl-7-methoxycoumarin, 3- (2-furoyl) -7-diethylaminocoumarin, 3- (p-diethylaminocinnamoyl) -7-diethylaminocoumarin, 7-methoxy-3.
-(3-Pyridylcarbonyl) coumarin, 3-benzoyl-5,7-dipropoxycoumarin, amines such as p
-Ethyl dimethylaminobenzoate, n-butyl p-dimethylaminobenzoate, phenethyl p-dimethylaminobenzoate, 2-phthalimidoethyl p-dimethylaminobenzoate, 2-methacryloyloxyethyl p-dimethylaminobenzoate, pentamethylene Bis (p-dimethylaminobenzoate), phenethyl and pentamethylene ester of m-dimethylaminobenzoic acid, p-dimethylaminobenzaldehyde, 2-chloro-4-dimethylaminobenzaldehyde, p-dimethylaminobenzyl alcohol, ethyl (p-dimethyl) Amino) benzoyl acetate, p-piperidinoacetophenone, 4-dimethylaminobenzoin, N, N-dimethyl-p-toluidine,
N, N-diethyl-m-phenetidine, tribenzylamine, dibenzylphenylamine, N-methyl-N-phenylbenzylamine, p-bromo-N, N-dimethylaniline, tridodecylamine, leuco crystal violet, and the like, and JP-A-53-133428, JP-B-57-1819,
Compounds disclosed in U.S. Pat. No. 57-6096, U.S. Pat. No. 3,615,455.

A combination of two or more kinds, for example, a combination of a 2,4,5-triarylimidazole dimer and 2-mercaptobenzoxazole or leuco crystal violet,
A combination of 4,4'-bis (dimethylamino) benzophenone and benzophenone or benzoin methyl ether described in U.S. Pat.
Combination of benzoyl-N-methylnaphthothiazoline and 2,4-bis (trichloromethyl) -6,4-methoxyphenyltriazole described in JP-A-57-23602.
Combination of dimethylthioxanthone and -4-dialkylaminobenzoic acid ester described in No.

The content of the photopolymerization initiator or the photopolymerization initiator system is based on the total weight of the photosensitive resin composition, preferably about 0.1 to 10% by weight,
More preferably, it is about 0.2 to 6% by weight.

The photosensitive resin composition used in the present invention contains a polymer binder, a monomer and a photopolymerization initiator as essential components, but if necessary, a thermal polymerization inhibitor, a plasticizer, a dye, a color changing agent and further to the surface of the substrate. The adhesion promoter and other auxiliaries may also be used in combination, whereby the desired photographic properties of the photoresist,
Properties such as printability and film physical properties can be adjusted.

The thermal polymerization inhibitor is added to prevent thermal polymerization of the photosensitive resin composition or polymerization over time, for example,
p-methoxyphenol, hydroquinone, t-butylcatechol, pyrogallol, 2-hydroxybenzophenone, 4-methoxy-2-hydroxybenzophenone, cuprous chloride, phenothiazine, chloranil, naphthylamine, β-naphthol, 2,6-di-t. -Butyl-p-cresol, nitrobenzene, dinitrobenzene, picric acid, p-toluidine and the like can be mentioned.

The plasticizer is added to control the physical properties of the film, and examples thereof include phthalates such as dibutyl phthalate, diheptyl phthalate, dioctyl phthalate and diallyl phthalate; triethylene glycol diacetate, tetraethylene glycol diacetate and the like. Glycol ester; Phosphoric acid ester such as tricresyl phosphate, triphenyl phosphate; Amide such as p-toluenesulfonamide, benzenesulfonamide, Nn-butylacetamide; Diisobutyl adipate, dioctyl adipate, dimethyl sebacate, Aliphatic dibasic acid esters such as dioctyl azelate and dibutyl maleate; triethyl citrate, tributyl citrate, glycerin triacetyl ester, butyl laurate, 4,5-diepoxy Cyclohexane-1,2-dicarboxylic acid dioctyl, and the like.

Examples of dyes are brilliant green, eosin, ethyl violet, erythrosine B, methyl green, crystal violet, basic fuchsine, phenolphthalein, 1,3-diphenyltriazine, alizarin red S, thymolphthaley, methyl violet 2B,
Quinaldine red, rose bengal, methanyl yellow, thymol sulfophthalein, xylenol blue,
Methyl orange, orange IV, diphenylthiocarbazone, 2,7-dichlorofluorescein, paramethyl red congo red, benzopurpurin 4B, α-naphthyl red, Nile blue A, phenacetaline, methyl violet, malachite green, parafuchsin, oil blue # 603 [manufactured by Orient Chemical Industry Co., Ltd.], Victoria Pure Blue BOH, Spiron Blue GN [manufactured by Hodogaya Chemical Industry Co., Ltd.], Rhodamine B, Rhodamine 6G and the like.

The color changing agent is added to the photosensitive resin composition so that a visible image can be provided by exposure. Specific examples of these include diphenylamine, dibenzylaniline, triphenylamine, diethylaniline, diphenyl-p-phenylenediamine, p-toluidine, 4, in addition to the above dyes.
4'-biphenyldiamine, o-chloroaniline, leuco crystal violet, leuco malachite green, leucoaniline, leucomethyl violet and the like can be mentioned.

Specific examples of the adhesion promoter include benzimidazole, benzthiazole, benzoxazole, benztriazole and the like compounds described in JP-B-50-9177, 2-mercaptobenzthiazole, 2-mercaptobenzimidazole and the like. And the like.

The photosensitive resin composition used in the present invention is used by dissolving the above-mentioned various constituents in a solvent and coating it on a support by a known method. The solvent used in this case, ethylene dichloride, monochlorobenzene, cyclohexanone, methyl ethyl ketone, acetone, methyl cellosolve acetate, ethyl acetate, methyl acetate, methyl cellosolve, 1-methoxy-2-propanol, toluene, xylene and the like alone, Or a mixture.

A preferable support has a thickness of 3 to 100 μm selected from films of polyamide, polyolefin, polyester, vinyl polymer, cellulose ester and the like. A particularly preferred support film is a transparent polyethylene terephthalate film having a thickness of about 10-25 μm.

When the tackiness of the photosensitive resin composition is high, it is preferable to provide a protective film on the coating layer particularly during continuous coating. In this case, a suitable protective film is a polyolefin, and a particularly preferable one is a polyethylene film having a thickness of 20 to 40 μm.

The dry film photoresist of the present invention is suitable as a photoresist for producing a printed circuit board, and the thickness of the photosensitive resin composition layer is preferably 0.1 to 500 μm, particularly preferably 1 to 200 μm.

The photosensitive resin composition can be developed with a weak alkaline aqueous solution such as sodium carbonate aqueous solution.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 Methacrylic acid / methyl methacrylate / 2-ethylhexyl acrylate / benzyl methacrylate (molar ratio 29/55/12
/ 4) 40 wt% solution of quaternary copolymer 37.5g (solvent is methyl ethyl ketone / 1-methoxy-2-propanol = 2/1 (weight ratio)) Monomer No. 1 in Table-1 8.0g Ethyl Michler's Ketone 0.04g Benzophenone 1.0g Tribromomethylphenyl sulfone 0.15g Leuco Crystal Violet 0.20g Malachite Green 0.013g 1-Phenyl-3-morpholinomethyl-1,3,4-triazole-2-thione 001 g p-toluenesulfonamide 0.5 g A photosensitive solution having the above composition was prepared, and a dry film thickness of about 25 μm was obtained on a polyethylene terephthalate film. It was applied so as to have a thickness of 50 μm, and a polyethylene film having a thickness of 30 μm was laminated. The developability of DFR thus obtained,
Table 2 shows the results of evaluation of the peeling property and the resolution.

Examples 2 and 3 DFR was obtained in the same manner as in Example 1 except that the compound of No. 2 or 3 in Table 1 was used as the monomer. Table 2 shows the results of evaluation of the developability, peeling property, and resolution of this DFR.

Comparative Examples 1 to 4 DFRs were obtained in the same manner as in Example 1 except that the compounds of Nos. 4 to 7 in Table 1 were used as the monomers. Table 2 shows the results of evaluation of the developability, peeling property, and resolution of this DFR.

The evaluation method of each performance is described below.

(Evaluation of developability) A24 type laminator (manufactured by DuPont) so that the photosensitive resin composition layer comes into contact with the copper surface while DFR is peeled off the polyethylene film on the copper clad laminate that has been surface-conditioned and dried. )
Was laminated at 120 ° C. Exposure was performed through a photomask with a step wedge (manufactured by FUJIFILM Corporation, △ OD = 0.15) at an exposure amount that made 9 steps clear (3K
w Ultra-high pressure mercury lamp double-sided simultaneous exposure system HMW-6-N type (manufactured by Oak Co.) is used. Peel off the polyethylene terephthalate film and use a 1 wt% sodium carbonate aqueous solution at 30 ° C.
The shortest development time was determined as the shortest time for removing the unexposed area by spraying at 1.5 kg / cm ² .

(Evaluation of film peeling property) After performing lamination and exposure in the same manner as in the evaluation of developability,
Develop for 1.5 times the shortest development time, and after drying, 2
The time until the resist was peeled off was measured by immersing it in a weight% potassium hydroxide aqueous solution.

(Evaluation of resolution) Lamination, exposure, and development are carried out in the same manner as in the evaluation of peeling property,
From the pattern of line / space = 1/1, the minimum line width without abnormalities such as cracks and twists was found.

Example 4 The photosensitive solution prepared in the same manner as in Example 1 was applied to a polyethylene terephthalate film having a thickness of 25 μm to give a dry film thickness of about 35 μm.
And a polyethylene film having a thickness of 30 μm was laminated. The thus-obtained DFR was laminated on the surface-dried and dried copper-clad laminate having holes of 2 to 6 mmφ in the same manner as in the evaluation of developability, and exposure was performed. Peel off the polyethylene terephthalate film, and use a 1 wt% sodium carbonate aqueous solution at 30 ° C at 2.0 Kg / cm ² for a minimum time of 2
Development was carried out by spraying for twice the time. After drying, a 45 ° C 35 ° C copper (II) chloride solution at 2.5 Kg / cm
Etching was done by spraying at ² for 4 minutes. The incidence of tearing of the tent membrane by the above operation was 0.1% or less.

Examples 5 and 6 Treatment was carried out in the same manner as in Example 4 except that the compound of No. 2 or 3 in Table 1 was used as the monomer. The incidence of tent film tear was less than 0.1%.

Comparative Examples 5 to 8 The same processes as in Example 4 were carried out except that the compounds of Nos. 4 to 7 in Table 1 were used as the monomers. The incidences of tearing of the tent membrane were 100%, 1.7%, 100%, and 0.5%, respectively.

"Effects of the Invention" The dry film photoresist of the present invention is particularly excellent in the strength of the tent film and has good developability and peeling property.

Claims (2)

[Claims] 1. A dry film photoresist comprising a flexible film support and a photosensitive resin composition layer, wherein the photosensitive resin composition layer is (A) soluble or swellable in an alkaline aqueous solution as an essential component. Certain polymer binder (B) Addition-polymerizable unsaturated compound represented by the following general formula (I) (However, in the formula, R is a hydrogen atom or a methyl group, X is a divalent organic group containing an aromatic ring, and n is an integer of 2 to 20.) (C) A photopolymerization initiator is contained. Dry film photoresist. 2. The dry film photoresist according to claim 1, wherein a protective film is provided on the photosensitive resin composition layer.