JPH0232353A - Dry film photoresist - Google Patents

Abstract

PURPOSE:To prevent the breakage of a tent film in developing and etching stages and to improve developability and film peelability by using a photosensi tive resin compsn. contg. a specific monomer. CONSTITUTION:A high-polymer binder which is soluble or swellabe in an aq. alkaline soln., the monomer expressed by the formula I, and a photopolymn. initiator are incorporated as the essential components into the photosensitive resin copsn. of the dry film photoresist consisting of a flexible film base and the photosensitive resin compsn. layer. In the formula I, R denotes a hydrogen atom or methyl group; X denotes a bivalent org. group contg. an arom. ring; n denotes 2-20 integer. The strength of the tent film is improved and the developability and film peelability are improved in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to dry film photoresists. More specifically, the present invention relates to a dry film photoresist that has excellent developability with an alkaline aqueous solution and peelability, and has excellent tent film strength.

"Prior Art" One of the methods for producing printed circuit boards is known to use dry film photoresist (hereinafter referred to as DFR). Regarding this DFR,
It is described in the Specification No. 1, and the more detailed usage method is as follows.
For example, rPhotore by W., S. DeForest
sistJMcGraw-Hill New Yo
rk (1975), pp. 163-212.

The main purpose of DFR is to protect through holes using the tenting method. In this method, the through-hole portion is covered with a photocured photosensitive resin composition layer, a so-called tent film, during the development and etching steps. This tent film may be damaged during the development and etching process.
It is extremely important that defects such as floating do not occur. However, in these processes, developing solution, etching solution, etc. are sprayed at high pressure, which often causes tears in the tent membrane in conventional DFR. The development of DFR was required.

This DFR uses an organic solvent for development and film removal,
Some use alkaline aqueous solutions, but in recent years environmental hygiene,
From an explosion-proof perspective, there has been a shift toward using alkaline aqueous solutions. However, when an alkaline aqueous solution is used, there is a problem in that the tent membrane tends to peel more easily than when an organic solvent is used.

By the way, DFR generally contains a polymeric binder, an addition polymerizable unsaturated compound (hereinafter referred to as a monomer), and a photopolymerization initiator as essential components.

Among these, polymer binders and monomers have an influence on the above-mentioned mechanical properties, but the influence of monomers is particularly dominant, and various monomers have been proposed in the past.

Specific examples of monomers used in DFR include acrylic or methacrylic esters of polyols, namely ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate. (meth)acrylate, nonaethylene glycol di(meth)acrylate, dodecaethylene glycol di(meth)acrylate, tetradeoxyethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, Trimethylolpropane di(meth)acrylate, pentaerythritol tritra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanethiol di(meth)acrylate, etc., or polyamine Acrylamide or methacrylamide obtained from methylene bis(meth)acrylamide, ethylene bis(meth)
Acrylamide, m-xylylenebis(meth)acrylamide, etc., or compounds containing urethane groups, i.e. di(2-methacryloxyethyl)-2,4-)lylene diurethane, di(2-acryloxyethyl)hexamethylene diurethane (Meth)acrylic urethane oligomers, such as 2.4-)rylene, obtained by further reacting β-hydroxyalkyl (meth)acrylate with a terminal incyanate compound obtained by reacting urethane, etc., or a polyol and a diisocyanate in advance. Oligomers obtained by reacting a reaction product of 4 moles of diisocyanate and 3 moles of ethylene glycol with 1 mole of β-hydroxyethyl acrylate, or acrylic acid or methacrylic acid esters modified and derived from bisphenol A, i.e. Reaction products of bisphenol A-epichlorohydrin epoxy resin prepolymers and acrylic acid or methacrylic acid, alkylene oxide adducts of bisphenol A or their hydrogenated acrylic acid or methacrylic esters, or aromatic polycarboxylic acids. Examples include esters, ie, compounds represented by the following structural formulas (U) to (IV).

In addition, as a dry film photoresist using a monomer containing a urethane group,
4 (alkaline development type), JP-A-59-204837,
61-77844, etc.

However, when these monomers are used, the strength of the tent film is insufficient, or the strength of the tent film is sufficient when an organic solvent is used for development, but when an alkaline aqueous solution is used. The membrane strength may be insufficient for
Or ■ Even if the strength of the tent membrane is sufficient, other properties required for use as a DFR are insufficient, such as improved image forming properties such as improved developer resistance and etching resistance. In particular, there was a major drawback in that the removability was reduced.

In this way, DFR, which is developed and peeled off using an alkaline aqueous solution,
In this case, the strength of the tent membrane is sufficient, and the developability and
It has been extremely difficult to obtain a DFR with excellent peelability.

Problems to be Solved by the Present Invention J Accordingly, an object of the present invention is to provide a dry film photoresist that does not cause tearing of the tent film during the development and etching steps and has good developability and peelability. It is. A further object of the present invention is to provide a dry film photoresist that has an excellent resist shape after development, has high resolution, and can be used satisfactorily in a plating process.

"Means for Solving the Problems" As a result of various studies, the present inventors have discovered that the above objectives can be achieved with a dry film photoresist using a photosensitive resin composition containing a specific monomer. , led to the present invention.

That is, the 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, in which the photosensitive resin composition layer is an essential component, and (A) Soluble or swellable polymeric binder (B) A monomer represented by the following general formula (1) (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. Achieved with photoresist.

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

Specific examples of diisocyanates containing aromatic rings include m-
Phenylene diisocyanate, p-phenylene diisocyanate, 2,4. ) lylene diisocyanate, 2.6
-Drylene diisocyanate, xylylene diisocyanate, 1,5-naphthylene diisocyanate, 1,4-
Examples include mesitylene diisocyanate, 4,4'-biphenylene diisocyanate, and 4,4'-diisocyanate diphenylmethane. 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 (meth)acrylate, dodecaethylene glycol mono(meth)acrylate, tridecaethylene glycol mono(meth)acrylate, tetradecaethylene glycol mono(meth)acrylate,
Pentadecaethylene glycol mono(meth)acrylate, hexadecaethylene glycol mono(meth)acrylate, heptadecaethylene glycol mono(meth)acrylate, octadecaethylene glycol mono(meth)acrylate, nonadecaethylene glycol mono(meth)acrylate, Eicosaethylene glycol mono(
Meth)acrylates and mixtures of two or more thereof can be mentioned. Particularly preferred specific examples include monoacrylates or monomethacrylates in which the repeating number of ethylene glycol is 2 to 40, and the average repeating number is 3 to 20. It is easily available as commercially available Blenmar PE-200, PE-350, etc.

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

Specific examples of the polyfunctional polymer include acrylic acid or methacrylic acid esters of polyols, acrylamide or methacrylamide obtained from polyamines, compounds containing urethane groups, and compounds obtained by reacting polyols with diisocyanates in advance. It is obtained by further reacting the terminal isocyanate compound obtained with β-hydroxyalkyl (meth)acrylate (
meth)acrylic urethane oligomer, bisphenol A
Examples include acrylic acid or methacrylic esters modified and derived from , compounds represented by structural formulas (II) to (IV), and the like.

Specific examples of the monofunctional monomer include tetraethylene glycol monophenyl ether acrylate, tetraethylene glycol mono p-nonylphenyl ether acrylate 1, tetrapropylene glycol mono p-nonylphenyl ether acrylate, 2-hydroxy-3
-Phenoxypropyl acrylate, phthalic acid monoacryloxyethyl ester, and succinic acid monoacryloxyethyl ester.

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

The polymer binder preferably used in the photosensitive resin composition used in the dry film photoresist of the present invention may be any polymer binder that is soluble or swellable in an aqueous alkaline solution. Specific examples include the methyl methacrylate/methacrylic acid copolymer disclosed in Japanese Patent Publication No. 46-32714;
Styrene/maleic acid mono-n-butyl ester copolymer disclosed in No. 5-38961, Japanese Patent Publication No. 56-33
Ethyl methacrylate/ethyl acrylate/methacrylic acid ternary copolymer disclosed in No. 413, JP-A-58-
Methyl methacrylate/methacrylic acid/2-ethylhexyl acrylate ternary copolymer or methacrylic acid/methyl methacrylate/2-ethylhexyl acrylate/n-butyl methacrylate quaternary copolymer disclosed in No. 1142, especially Methacrylic acid/methyl methacrylate/acrylic 'f11 disclosed in Application No. 61-295441
Examples include 2-ethylhexyl/benzyl methacrylate quaternary copolymer.

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.

The photopolymerization initiator suitably used in the photosensitive resin composition used in the dry film photoresist of the present invention may be a single compound capable of initiating the polymerization of the above-mentioned polymerizable unsaturated compound, or a combination of two or more kinds. Any photoinitiator system of combinations of compounds can be used. Preferably, the photoinitiator or photoinitiator system has about 3000
It contains at least one component having a molecular extinction coefficient of at least about 50 within the range of 8000A to 3300 to 5000A.

Preferred specific examples of the photopolymerization initiator include the following compounds. 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,
2,4.5-triarylimidazole dimers such as benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin phenyl ether, etc., such as 2-(o-chlorophenyl)-4,
5-diphenylimidazole dimer, 2-(0-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazole dimer, 2-(0-fluorophenyl)-4,
5-diphenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer, etc., polyhalogen compounds , such as carbon tetrabromide, phenyltribromomethylsulfone, phenyltrichloromethylketone, etc., coumarins, such as 3-
(2-benzofuroyl)-7-dinithylaminocoumarin, 3-(2-benzofuroyl)-7-(1-pyrrolidinyl)coumarin, 3-benzoyl-7-ethylaminocoumarin, 3-(o-methoxybenzoyl)- 7-ethylaminocoumarin, 3-(p-dimethylaminobenzoyl)-7-dinithylaminocoumarin, 3.3-carbonylbis(5,7-d-n-propoxycoumarin), 3.
3'-carbonylbis(7-dinithylaminocoumarin)
, 3-benzoyl-7-medoxycoumarin, 3-(2-
furoyl)-7-diethylaminocoumarin, 3-(p-
amines such as ethyl p-dimethylaminobenzoate, p-dimethyl n-butyl aminobenzoate, p-
Phenethyl dimethylaminobenzoate, 2-phthalimidoethyl p-dimethylaminobenzoate, 2-methacryloyloxyethyl p-dimethylaminobenzoate, pentamethylene bis(p-dimethylaminobenzoate), phenethyl and pentamethylene m-dimethylaminobenzoate ester, p-dimethylaminobenzaldehyde, 2-
Chlor-4-dimethylaminobenzaldehyde, p-dimethylaminobenzyl alcohol, ethyl (p-dimethylamino)benzoyl acetate, p-piperidinoacetophenone, 4-dimethylaminobenzoin, N,N-
Dimethyl-p-)luidine, N,N-diethyl-m-phenetidine, tribenzylamine, dibenzylphenylamine, N-methyl-N-phenylbenzylamine, p
-bromo-N, N-dimethylaniline, tridodecylamine, leuco crystal violet, etc., and JP-A-5
No. 3-133428, Special Publication No. 57-1819, No. 57
-6096, a compound disclosed in U.S. Patent No. 3,615,455.

A combination of two or more types, such as a combination of a 2.4.5-) realyl imidazole dimer and a 2-mercaptobenzoxazole or leuco crystal violet, 4.4'-bis( dimethylamino)benzophenone and benzophenone or benzoin methyl ether; a combination of benzoyl-N-methylnaphthothiazoline and 2,4-bis(trichloromethyl)-6,4-methoxyphenyltriazole as described in U.S. Pat. No. 4,239,850; 1, and the combination of dimethylthioxanthone and 4-dialkylaminobenzoic acid ester described in JP-A-57-23602.

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

The photosensitive resin composition used in the present invention has a polymeric binder, a monomer, and a photopolymerization initiator as essential components, but if necessary, a thermal polymerization inhibitor, a plasticizer, a pigment, a color change agent, and a photopolymerization agent may be added to the substrate surface. The adhesion promoter and other auxiliary agents may be used in combination, thereby making it possible to adjust the desired properties of the photoresist, such as its photographic properties, print-out properties, and film properties.

Thermal polymerization inhibitor is added to prevent thermal polymerization or temporal polymerization of the photosensitive resin composition, 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- Examples include butyl-p-cresol, nitrobenzene, dinitrobenzene, bitalic acid, p-toluidine, and the like.

Plasticizers are added to control the physical properties of the film, and include, for example, phthalate esters such as dibutyl phthalate, diallyl phthalate, dioctyl phthalate, and diallyl phthalate; glycols such as triethylene glycol diacetate and tetraethylene glycol diacetate. Esters; Phosphate esters such as tricresyl phosphate and triphenyl phosphate; Amides such as p-)luenesulfonamide, benzenesulfonamide, and N-n-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, dioctyl 4゜5-jepoxycyclohexane-1,2-dicarboxylate, etc. can be mentioned.

Examples of pigments include brilliant green, eosin, ethyl violet, erythrosin B, methyl green, crystal violet, pacific tuxin, phenolphthalein, 1,3-diphenyltriazine, alizarin red S, thymolphthalein, methyl violet 2B, Quinaldine red, rose bengal, methanyl yellow thymol sulfophthalein, xylenol blue methyl orange, orange ■, diphenylthiocarbazone, 2,7-dichlorofluorescein, rose methyl red, Congo red, benzobrulin 4B, α-naphthyl Red, Nile Blue A, phenacetaline, methyl violet, malachite green, paratuxin, oil blue #603 [manufactured by Orient Chemical Industry Co., Ltd.],
Victoria Pure Blue BOH, Spiron Blue GN [
These include Rhodamine B, Rhodamine 6G, and the like manufactured by Hodogaya Chemical Industry Co., Ltd.

A color change agent is added to the photosensitive resin composition so that it can provide a visible image upon exposure to light. Specific examples of these include, in addition to the above dyes, diphenylamine, dibenzylaniline, triphenylamine, diethylaniline, diphenyl-p-phenyl diamine, 1)-) luidine,
4,4"-biphenyldiamine, 0-chloroaniline,
Examples include leuco crystal violet, leucomalachite green, leucoaniline, and leucomethyl violet.

Specific examples of adhesion promoters include benzimidazole, benzthiazole, benzoxazole, benztriazole, etc. compounds described in Japanese Patent Publication No. 50-9177, 2-mercaptobenzthiazole, 2-mercaptobenzimidazole, etc. Examples include the compounds described in No.

The photosensitive resin composition used in the present invention is used by dissolving the various constituent components described above in a solvent and applying the solution onto a support by a known method. Solvents used in this case include ethylene dichloride, monochlorobenzene, cyclohexanone, methyl ethyl ketone, acetone, methyl cellosolve acetate, ethyl acetate, methyl acetate, methyl cellosolve, 1-methoxy-2-propanol, toluene, xylene, etc. , or a mixture.

Suitable supports are those selected from films of polyamides, polyolefins, polyesters, vinyl polymers, cellulose esters, etc. and have a thickness of 3 to 100 μm. Particularly suitable support films have a thickness of about 10 to 25 μm.
It is a transparent polyethylene terephthalate film with a thickness of m.

When the photosensitive resin composition has high tackiness, it is preferable to provide a protective film on the coating layer especially during continuous coating. In this case, suitable protective films include polyolefins, and particularly preferred are ~40μ
Mention may be made of polyethylene films with a thickness of m.

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

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

The present invention will be explained in more detail below with reference to Examples.

Example 1 37.5 g of methacrylic acid/methyl methacrylate/2-ethylhexyl acrylate/benzyl methacrylate (molar ratio 29155/12/4) 40% by weight solution of quaternary copolymer (solvent: methyl ethyl ketone/1- Methoxy-2-propertool = 2/1 (weight ratio)) Monomer of NO61 in Table 1 8.0g Ethyl Michler's Ketone 0.04g Benzophenone
1. Og tribromomethylphenyls 0.15g sulfone leuco crystal violet 0.20g tomalachite green 0.013g 1-phenyl-3-morpholy 0.01g trimethyl-1,3
, 4-triazole-2-thione P-) luenesulfonamide 0.5 g A photosensitive solution having the above composition was prepared, and applied to a 25 μm thick polyethylene terephthalate film to give a dry film thickness of about 50 μm. Laminated with polyethylene film. Table 2 shows the results of evaluating the developability, peelability, and resolution of the D F'R thus obtained.

Examples 2 and 3 DFR was obtained in the same manner as in Example 1 except that compounds No. 2 or 3 in Table 1 were used as monomers. The results of evaluating the developability, peelability, and resolution of this DFR are shown below.
Shown in 2.

Comparative Examples 1 to 4 DFR was obtained in the same manner as in Example 1, except that compounds Nos. 094 to 7 in Table 1 were used as monomers.

Table 2 shows the results of evaluating the developability, peelability, and resolution of this DFR.

The evaluation method for each performance is described below.

(Evaluation of developability) A DFR was placed on a prepared and dried copper-clad laminate using an A24 laminator (DuPo) while peeling off the polyethylene film so that the photosensitive resin composition layer was in contact with the copper surface.
nt) at 120°C. Step wedge (manufactured by Fuji Film Co., Ltd., AOD=0.1
5) The polyethylene terephthalate film was exposed through a photomask at an exposure amount that cleared the 9th step (using a 3Kw ultra-high pressure mercury lamp double-sided simultaneous exposure device HMW-6-N manufactured by Kuoak Co., Ltd.). Then, the shortest development time was determined by spraying a 1% by weight aqueous sodium carbonate solution at 30"C at a rate of 1.5 kg/cm" to remove the unexposed area.

(Evaluation of peelability) After laminating and exposing in the same way as in the evaluation of developability,
Develop for 1.5 times the shortest development time, and after drying,
The resist was immersed in a 2% by weight aqueous potassium hydroxide solution and the time required for the resist to peel off was measured.

(Evaluation of resolution) Laminate, expose, and develop in the same way as the evaluation of peelability.
Among the patterns with line/space = 1/1, the smallest line with no abnormalities such as line distortion or twisting was determined.

Example 4 A photosensitive solution prepared in the same manner as in Example 1 was coated on a 25 μm polyethylene terephthalate film to a dry film thickness of approximately 35 μm.
It was coated to a thickness of 30 μm and laminated with a 30 μm polyethylene film. The DFR thus obtained was laminated on a copper-clad laminate with holes of 2 to 6 mm in diameter that had been prepared and dried, and exposed to light in the same manner as in the evaluation of developability. Peel off the polyethylene terephthalate film and
2.0Kg of 1% by weight sodium carbonate aqueous solution at 0°C
/ cm” for twice the minimum time. After drying, at 35°B at 45°C.
By spraying a copper (II) hexachloride aqueous solution at 2.5 kg/cm2 for 4 minutes, the incidence of tent membrane tearing in 0 or more etching operations was 0.1% or less.

Examples 5 and 6 The same treatment as in Example 4 was carried out except that the compound No. 12 or 3 in Table 1 was used as the monomer. The incidence of tentorium rupture was less than 0.1%.

Comparative Examples 5 to 8 The treatment was carried out in the same manner as in Example 4, except that compounds No. 4 to 7 in Table 1 were used as monomers. The incidence of tentorium rupture was 100% and 1.7%, respectively.

They were 100% and 0.5%.

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

Claims (2)

[Claims] (1) In a dry film photoresist comprising a flexible film support and a photosensitive resin composition layer, the photosensitive resin composition layer is an essential component (A) Molecular binder (B) Addition-polymerizable unsaturated compound represented by the following general formula (I) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (I) (However, in the formula, R is a hydrogen atom or a methyl group, and X is an aromatic (C) A dry film photoresist characterized by containing a photopolymerization initiator (a divalent organic group containing a ring, n being an integer of 2 to 20). (2) The dry film photoresist according to claim (1), further comprising a protective film provided on the photosensitive resin composition layer.