JPH04120541A - Production of polymer, photosensitive resin composition and photosensitive element using same - Google Patents

Abstract

PURPOSE:To attain development with high resolution in a short time with an aq. weak alkali soln. and to enable removal in a short time by polymerizing a mixed soln. contg. two kinds of specified monomers in the presence of a chain transfer agent. CONSTITUTION:A mixed soln. contg. a monomer represented by general formula I and a monomer represented by general formula II is polymerized in the presence of a chain transfer agent. In the formulae I, II, R1 is H or methyl, R2 is 1-8C alkylene or a benzene ring, R3 is 1-5C alkylene, R4 is H or methyl and n is an integer of 1-10. A copolymer having superior adhesion and alkali etching resistance as well as satisfactory removability and flexibility is obtd.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for producing a polymer, a photosensitive resin composition, and a photosensitive element using the same (hereinafter simply referred to as a "photosensitive film"). .

[Conventional technology]

Conventionally, photosensitive resin compositions and photosensitive films obtained using the same have been widely used as resist materials for etching, plating, etc. in the fields of printed wiring board manufacturing, metal precision processing, etc. . There are two types of photosensitive films: solvent-developable photosensitive films that are developed using chlorinated organic solvents and alkaline-developable photosensitive films that are developed using alkaline aqueous solutions. For this reason, alkali-developable photosensitive films are often used.

However, this alkali-developable photosensitive film has lower resistance to etching, especially alkali etching, than conventional organic solvent-developable photosensitive films, and therefore has many limitations in processing and often poses problems when used. There are two types of etching liquids: (1) acidic etching liquids, such as cupric chloride and ferric chloride; and (2) alkaline etching liquids, such as ammonia-based alkaline etching liquids, which are often used. Conventional organic solvent-developable photosensitive films show equivalent resistance to these two types of etching solutions, or alkaline-developable photosensitive films use a high molecular weight material containing a large number of carboxyl groups in the polymer that imparts film properties. Although it is resistant to weakly alkaline developers, it is not sufficiently resistant to relatively strong alkaline etching solutions.
The problem is that it is extremely sensitive to the pH 1 temperature of the alkaline etching solution, the etching time, etc., and the tolerance for working conditions is very narrow.

In addition, alkaline developable photosensitive films can be developed using organic solvents.
Another problem has been that the removability of the resist after pattern formation by etching or plating is inferior to image-type photosensitive resin compositions. That is, when an organic solvent-developable photosensitive film is used, the resist is generally removed using a solvent such as methylene chloride, and the peeled pieces become small pieces, making it easy to clean the printed wiring board and using a stripping solution or Maintenance of the peeling machine is easy. On the other hand, when an alkali-developable photosensitive film is used, the resist is generally removed using a heated aqueous solution of hydroxide or potassium hydroxide; This becomes a "seaweed" shape and re-adheres to the printed wiring board, and it is difficult to regenerate by filtering the stripping solution, which poses a major problem in work.

Japanese Patent Publication No. 46-12714 (the binder is, for example, methyl methacrylate/methacrylic acid copolymer), Japanese Patent Publication No. 54-34827 (the binder is, for example, methyl methacrylate/2-ethylhexyl methacrylate/methacrylic acid) ), Japanese Patent Publication No. 55-3898
No. 1 (the binder is, for example, a styrene/maleic acid mono-n-butyl ester copolymer), Japanese Patent Publication No. 56
-33418 (the binder is, for example, a ternary copolymer of ethyl methacrylate/ethyl acrylate/methacrylic acid), Japanese Patent Publication No. 54-25957 (the binder is
For example, a quaternary copolymer of styrene/methyl methacrylate/ethyl acrylate/methacrylic acid), JP-A-52
99810 (the binder is, for example, benzyl methacrylate/methacrylic acid copolymer), Japanese Patent Publication No. 581
No. 2577 (the binder is, for example, acrylonitrile/
(a terpolymer of 2-ethylhexyl methacrylate/methacrylic acid), Japanese Patent Publication No. 55-6210 (the binder is, for example, a terpolymer of methyl methacrylate/ethyl acrylate/acrylic acid) The binder is, for example, a ternary copolymer of benzyl methacrylate/methyl methacrylate/methacrylic acid, as disclosed in Japanese Patent Publication No. 6Q-159743. Polymer), Japanese Patent Publication No. 61-292815, Japanese Patent Publication No. 62-292816
No. 3, in which the binder is, for example, a terpolymer of 2-phenoxyethyl acrylate/methacrylic acid/methyl methacrylate, describes alkali-developable photosensitive resin compositions using various binders. has been done. however,
Currently, these materials cannot simultaneously satisfy all of the characteristics of alkali etching resistance, development time, releasability, adhesion to copper, cold flow, and flexibility.

[Problem to be solved by the invention]

It is an object of the present invention to overcome the above-mentioned problems of conventional alkali-developable photosensitive resin compositions and photosensitive films using the same, and to provide a multicomponent compound useful as a binder for alkali-developable photosensitive resin compositions. In addition to providing a method for producing a polymer,
It has strong resistance to alkaline etching, can be developed with high resolution in a short time using a weak alkaline aqueous solution, can be peeled off in a short time, and has small peeling pieces (sufficient to be laminated to a substrate as a photosensitive film). The object of the present invention is to provide a photosensitive resin composition that has flexibility, strong adhesion to its substrate, and less cold flow, and a photosensitive film using the same.

[Means to solve the problem]

The present invention relates to the general formula (I) Ri [wherein R1 represents a hydrogen atom or a methyl group, and R2 represents an alkylene group having 1 to 8 carbon atoms or a benzene ring]
Monomers represented by the general formula (I[) [wherein Ri represents the above, R3 represents an alkylene group having 1 to 5 carbon atoms, R4 represents a hydrogen atom or a methyl group, and n is 1
A method for producing a multicomponent copolymer, characterized by polymerizing a mixture containing a monomer represented by [representing an integer of ~10] in the presence of a chain transfer agent, and (i) a method for producing a multicomponent copolymer, which is characterized by polymerizing a mixture containing a monomer represented by The present invention relates to a photosensitive resin composition containing a multicomponent copolymer, (ii) a vinyl monomer, and (ii) a photoinitiator.

The present invention further relates to a photosensitive film formed by laminating the above photosensitive resin composition on a support film.

The present invention will be explained in detail below.

First, the monomer components used to produce the multi-component copolymer of the present invention will be explained.

The monomer represented by the general formula (1) is included as an essential component in the monomer components used to construct the multi-valve body.

R2 in the general formula (1) is an alkylene group having 1 to 8 carbon atoms, but those having 9 or more carbon atoms have poor copolymerizability.

Examples of the monomer represented by general formula (I) include β-
Examples include acryloyloxyethyl hydrogen succinate, β-methacryloyloxyethyl hydrogen succinate, and β-methacryloyloxyethyl hydrogen phthalate. Among these, β-acryloyloxyethyl hydrogen succinate and β-methacryloyloxyethyl hydrogen succinate are preferred.

These monomers are commercially available from Shin-Nakamura Chemical Co., Ltd., etc., but they often contain difunctional compounds as impurities, and in this case, gels are often added during the production of copolymers. It should be noted that this may cause oxidation.

The monomer represented by general formula (1) is preferably contained in an amount of 10 to 40% by weight in the total monomers used to constitute the multi-component copolymer.

If it is less than 10% by weight, developability tends to deteriorate;
% by weight, cold flow tends to occur.

The monomer represented by the general formula (TL'') is included as an essential component in the monomer components used to constitute the multi-component copolymer.

n in general formula (II) is 1-10. Those with n=0 are difficult to obtain, and those with n of 11 or more have poor copolymerizability. Moreover, R8 in general formula (II) represents an alkylene group having 1 to 5 carbon atoms. Those having 6 or more carbon atoms have poor copolymerizability.

Examples of the monomer represented by general formula (II) include 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate, 2-phenoxypropyl acrylate, 3-phenoxypropyl acrylate, phenoxyjethoxy acrylate, Phenoxytriethoxy acrylate, phenoxydibropoquine acrylate, 2-phenoxypropyl methacrylate, 3-phenoxypropyl methacrylate, phenoxyjethoxy methacrylate, phenoxytriethoxy methacrylate, phenoxydibropoquine methacrylate, etc. I can do it. 2-phenoxyethyl acrylate and 2-phenoxyethyl methacrylate are preferred. Among these, 2-phenoxyethyl acrylate and 2-phenoxyethyl methacrylate are commercially available, but they may contain difunctional compounds as impurities, and in this case, it is difficult to produce a copolymer. Care must be taken as gelation may sometimes occur.

The monomer represented by general formula (n) contains 5 to 6 monomers in the total monomers.
It is preferably contained in a range of 0% by weight. If it is less than 5% by weight, the alkali etching resistance tends to deteriorate;
If it exceeds 60% by weight, developability tends to be poor.

In addition to the monomers represented by the above general formulas (1) and (II), other monomers can be used as needed within a range that does not deteriorate the properties.

Other monomers include, for example, methyl methacrylate,
Examples include methyl acrylate, ethyl methacrylate, ethyl acrylate, n-propyl methacrylate, n-propyl acrylate, cyclohexyl methacrylate, and cyclohexyl acrylate, with methyl acrylate and methyl methacrylate being preferred.

The other monomers are preferably contained in an amount of 5 to 40% by weight in the total monomers used to constitute the multi-component copolymer. When the content of other monomers is large, properties such as cold flow tend to deteriorate.

The use of other monomers is advantageous in terms of cost, availability, etc.

The monomer components used to construct the multi-component copolymer are:
The monomer of the general formula (I) is 10 to 40% by weight, the monomer of the general formula (I
5 to 60% by weight of monomer I) and 5 to 4% of other monomers
0% by weight, and the total amount of all monomers is 100% by weight
It is preferable that the content is as follows.

In the present invention, the multi-component copolymer can be easily produced by known polymerization techniques such as solution polymerization, suspension polymerization, emulsion polymerization, and bulk polymerization using the monomers shown above. can. However, if a chain transfer agent is not used during polymerization, the viscosity of the multi-component copolymer may abnormally increase during polymerization, or the molecular weight distribution may be abnormal (for example, it may have a shoulder in the high molecular weight region or have two peaks, etc.). ) or
This may even cause gelation. This is considered to be due to the impurity bifunctional compound contained in the monomer represented by general formula (1) or the monomer represented by general formula (II) used during polymerization of the multi-component copolymer.

The present invention solves the above problems and performs a polymerization reaction in the presence of a chain transfer agent in order to always produce a stable multicomponent copolymer.

The polymerization reaction temperature is preferably 60°C to 130°C, more preferably 70°C to 100°C, and 75°C
It is particularly preferred that the temperature is between 85°C and 85°C. At temperatures below 60° C., the decomposition rate of the polymerization initiator is slow, the synthesis time becomes long, and productivity tends to deteriorate. On the other hand, 130°
When synthesized at a temperature exceeding C, the decomposition rate of the initiator is too fast, making it difficult to control the reaction temperature, and when the reaction temperature is higher than the boiling point of the solvent used, it becomes difficult to carry out the reaction at normal pressure. .

Post-chaining agents include, for example, 2-ethylhexylthio-n-propionate, t-dodecylmercaptan,
Examples include n-dodecyl mercaptan, methyl mercaptan, trimethylolpropane trithiopropinate, diphenyl disulfide, 4,4 diphenyl disulfide aniline, phenol, thiophenol and the like. 2-
Ethylhexylthio-n-propionate, t-dodecylmercaptan, and trimethylolpropane trithiopropinate are preferable in terms of characteristics. Among these, 2-ethylhexylthio-n-propionate is more preferred because it has no odor.

Examples of the initiator include 2,2'-azobisbutyronitrile (abbisisobutyronitrile), 2,2-azobis-2,4-dimethylvaleronitrile, dimethyl-2
, 2'-azobisbutyrate, 1,1-azobiscyclohexanecarbonitrile, 1. 1-Azobis(1
Ab compounds such as -cyclohexanecarbonitrile), 2.2'-azobis(2゜4.41-limethylbentane), 2.2°-azobis(2-methylpropane), -butyl hydroperoxide, di-t Examples include organic peroxides such as -butyl peroxide, 2,5-dimethylhexane-2,5 dihydroperoxide, cyclohexane peroxide, and acetylacetone peroxide. Azobisisobutyronitrile is most preferred because of its advantages such as not having a too high decomposition temperature and having little residual monomer.

The amount of the chain transfer agent and the amount of the initiator are such that the weight average molecular weight of the multi-component copolymer (as calculated by GPC in terms of polystyrene) is 10.
Range of 000 to 500,000, dispersity (Mw/Mn
) It is preferable to control it so that it is within the range of 3.0 or less. Specifically, it is preferable to use the chain transfer agent in an amount of 0.05 to 0.3% by weight based on the total amount of all monomers, and at that time, the initiator is used in an amount of 0.05 to 0.3% by weight based on the total amount of all monomers. It is preferable to use it in an amount of 0.1 to 0.5% by weight based on the total amount.

The multicomponent copolymer thus obtained is useful as a binder in a photosensitive resin composition, and is useful as a binder in a photosensitive resin composition.
As described above, the fat composition comprises (i) the above multi-component copolymer, (
5) It contains a vinyl monomer and (ii) a photoinitiator.

The degree of dispersion of the multicomponent copolymer used in the photosensitive resin composition of the present invention is preferably 3.0 or less, more preferably 2.8 or less, particularly preferably 2.5 or less. When the degree of dispersion exceeds 3.0, since the composition contains a relatively large amount of low molecular weight polymer, peelability tends to decrease when the composition is laminated and used as a photosensitive film.

The weight average molecular weight of the multi-component copolymer is 10,000 to 50
Preferably, it is in the range of 0,000.

If it is less than 10,000, developer resistance tends to be low, and if it exceeds 500,000, developability tends to be poor.

In addition, the multi-component copolymer has an acid value of 60 to 200 mgKOH.
/g is preferably in the range of 60 to 100 mgK
OH/g is more preferably in the range of 65 to 85
A range of mgKOH/H is particularly preferred. If the acid value is too low, developability tends to be poor, and if the acid value is too high, alkali etching resistance tends to be poor.

Next, the polymers used as the (i) multicomponent copolymer in the present invention are illustrated as Table 1. These can be obtained, for example, by a radical solution polymerization method using 2-ethylhexylthio-n-probionate as a chain transfer agent and azobisisobutyronitrile as a polymerization initiator. Further, Table 2 shows examples of polymers in which no chain transfer agent was used.

As the vinyl monomer (ii) used in the photosensitive resin composition of the present invention, for example, a compound obtained by reacting a polyhydric alcohol with an α,β-unsaturated carboxylic acid, for example,
Polyethylene glycol di(meth)acrylate (means acrylate or methacrylate. The same applies hereinafter) (
(having 2 to 14 ethylene groups), trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethoxytri(meth)acrylate, trimethylolpropanepropoxytri(meth)acrylate, Tetramethylolmethane tri(meth)acrylate, tetramethylolmethanetetra(meth)acrylate, polypropylene glycol di(meth)acrylate (with 2 to 14 propylene groups), dipentaerythritol penta(meth)acrylate, dipentaerythritol Bisphenol A polyoxyethylene di(meth)acrylate, such as hexa(meth)acrylate, e.g. bisphenol A dioxyethylene di(meth)acrylate,
α-, β-
Compounds obtained by adding unsaturated carboxylic acids, e.g.
Trimethylolpropane triglycidyl ether triacrylate, bisphenol A diglycidyl ether diacrylate, etc., a polycarboxylic acid such as phthalic anhydride, and a substance having a hydroxyl group and an ethylenically unsaturated group, such as β-hydroxyethyl (meth) Esterified products with acrylates, etc., alkyl esters of acrylic acid or methacrylic acid, such as (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid ethyl ester,
Acrylic acid butyl ester, (meth)acrylic acid 2-ethylhexyl ester, tolylene diisocyanate and 2
-Urethane (meth) of a reaction product with hydroxyethyl (meth)acrylic acid ester or a reaction product of trimethylhexamethylene diisocyanate, cyclohexane dimetatool, and 2-hydroxyethyl (meth)acrylic acid ester
Examples include acrylates, monomers represented by the general formula (I) and general formula (II), and the like. These can be used in combination of two or more types.

Examples of the photoinitiator (iii) used in the photosensitive resin composition of the present invention include benzophenone and N.

N-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone), N,N'-tetramethyl-4,
4°-diaminobenzophenone, 4-methoxy-4°-
Aromatic ketones such as dimethylaminobenzophenone, 2-ethylanthraquinone, and phenanthrenequinone; benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, and benzoin phenyl ether; benzoin such as methylbenzoin and ethylbenzoin;
acridin-9-yl) diester compounds of acrylic acid, acridine compounds such as 9-phenylacridine and 9-pyridyl acridine, 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-(0-methoxyphenyl)-4,5-diphenylimidazole dimer, 2-(p-methoxyphenyl)-4°5-diphenylimidazole dimer, 2,4 -di(p-methoxyphenyl)-5-phenylimidazole dimer, 2-(2,
4-dimethoxyphenyl)-4,5-diphenylimidazole dimer, 2-(p-methylmercaptophenyl)
-4,5-diphenylimidazole dimer, etc. 2. 4
．． Examples include 5-triarylimidazole dimer. These can be used in combination of two or more types.

(i) The amount of the multicomponent copolymer used is preferably 20 to 90 parts by weight, more preferably 50 to 80 parts by weight, and particularly preferably 65 to 75 parts by weight. In addition, (ii) the amount of vinyl monomer used is 10 to 80
The amount is preferably 20 to 50 parts by weight, more preferably 20 to 50 parts by weight. (i) multi-component copolymer and (ii)
The amount of vinyl monomer used is determined within the above range so that the total amount of (i) multi-component copolymer and (ii) vinyl monomer is 100 parts by weight. (ii) If the amount of vinyl monomer used is too small, the photocured product (exposed resist) will be brittle and sufficient physical properties may not be obtained; if it is too large, sufficient photosensitivity may not be obtained. .

(iii) The amount of photoinitiator used is 0 parts by weight based on 100 parts by weight of the total amount of (i) multi-component copolymer and (ii) vinyl monomer.
．． It is preferable to set it as 03-20 parts by weight, and 0.05-20 parts by weight.
More preferably, the amount is 10 parts by weight.

If the amount used is too small, sufficient photosensitivity will not be obtained,
If the amount is too large, light absorption at the surface of the composition increases during exposure, and the internal photocuring may become insufficient.

The photosensitive resin composition of the present invention may optionally contain a plasticizer,
A thermal polymerization inhibitor, dye, pigment, filler, adhesion imparting agent, etc. can be blended.

The photosensitive resin composition of the present invention can be used by applying it as a liquid resist onto a metal surface, such as copper, nickel, or chromium, preferably copper, and then coating it with a protective film after drying.
Or used as a photosensitive film. The thickness of the photosensitive resin composition layer varies depending on the application, but the thickness after drying is 10
It is about 100 μm. When using liquid resist,
An inert polyolefin film such as polyethylene or polypropylene is used as the protective film.

The photosensitive film is obtained by coating a photosensitive resin composition on a support film such as polyester, drying and laminating the layers, and, if necessary, laminating a protective film such as polyethylene. The photosensitive resin composition may be mixed with other solvents and applied as a solution, if necessary.

The photosensitive resin composition layer is irradiated with actinic rays through a negative or positive mask pattern called artwork or negative film, and then developed with a developer to form a resist pattern. As the active light rays used at this time, those that effectively emit ultraviolet rays, such as carbon arc lamps, ultra-high pressure mercury lamps, high pressure mercury lamps, and xenon lamps, are used.

The developer used is one that is safe, stable, and has good operability; specific examples include lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and sodium hydrogen carbonate. , potassium hydrogen carbonate, sodium silicate, sodium phosphate, sodium metasilicate, and the like. Particularly preferred is a 1-2% aqueous solution of sodium carbonate.

Development methods include a dip method, a paddle method, a spray method, etc., and a high-pressure spray method is most suitable for improving resolution.

〔Example〕

Next, the present invention will be explained by examples.

[Example of synthesis of multicomponent copolymer]

A mixed solvent (hereinafter referred to as mixed solvent) as a polymerization solvent of ethylene glycol monomethyl ether/toluene (weight ratio 6/4) was placed in a fourth flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube. 2-phenoxyethyl acrylate 210g, β-methacryloyloxyethyl hydrogen succinate) 180
g.

Mixed solvent A: 120 g of 210 g of methyl methacrylate, 24 g of azobisisobutyronitrile, and 1.2 g of 2-ethylhexylthio-n-propionate as a chain transfer agent.
The solution was added dropwise into the flask over 4 hours while keeping the temperature at 80° C. and stirring the flask. After the dropwise addition was completed, 60 g of mixed solvent A was added, kept warm at 80° C. for 4 hours, and then cooled to obtain a solution of polymer 1. The weight average molecular weight of this Polymer 1 was measured by GPC and was 90,000 (in terms of polystyrene). Also, the acid value is 73 (mgKO
H/g).

Polymer 4, Polymer 7, and Polymer 10 shown in Table 1 above were synthesized in the same manner as in the synthesis of Polymer 1.

In addition, in the same manner as in the synthesis of Polymer 1, Polymer 17 and Polymer 1, which are comparative polymers outside the scope of the present invention, shown in Table 3 below.
8, Polymer 19 and Polymer 20 were synthesized.

Examples 1 to 4 and Comparative Examples 1 to 4 Examples 1 to 4 are polymers 1.4.7 and 10 listed in Table 1.
and Comparative Examples 1 to 4 are polymers 17 and 13 listed in Table 3.
, 19 and 20 were used.

[Preparation of solution of photosensitive resin composition]

182 g of the polymer solution obtained in the synthesis example (solid content 65 g)
);) 0.8 g of ribromophenyl sulfone, 1 g of leuco crystal violet, 1 g of malachite green,
s g ; N, N'-tetraethyl-4,4゛-diamino-benzophenone 0.15 g as photoinitiator, benzophenone &ig, p-dimethylaminobenzoic acid ethyl ester &5 g; methyl ethyl ketone 25 g 1 methanol 3 g; as vinyl monomer 25 g of BPE-10 (trade name, manufactured by Shin Nakamura Chemical Co., Ltd., bisphenol A polyoxydiethylene dimethacrylate), MECHPP (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd., γ-chloroβ-hydroxypropyl = β゛-methacryloyloxy) 10 g of ethyl 〇-phthalate) was blended to obtain a solution of a photosensitive resin composition.

[Preparation of samples for characteristic evaluation]

The solution of the photosensitive resin composition was uniformly applied onto a 208°C thick polyethylene terephthalate film, and the solution was heated at 100°C.
The film was dried for about 10 minutes in a hot air convection dryer to obtain a photosensitive film. The film thickness of the photosensitive resin composition after drying is 40 μm
Met.

On the other hand, a copper-clad laminate (manufactured by Hitachi Chemical Co., Ltd., M
The copper surface of CL-E-61) was polished with a #800 sand vapor, washed with water, and dried with an air stream. The resulting copper-clad laminate was heated to 60°C, and the photosensitive layer was applied on the copper surface. The resin composition layer was laminated while being heated to 120° C. to obtain a sample for characteristic evaluation.

Using this characteristic evaluation sample, the following (a-1) and (a-
Various properties were evaluated as shown in 2) and (a-3).

(a-1) A negative film was applied to the sample for characteristic evaluation, and a 3KW high-pressure mercury lamp (manufactured by Oak Manufacturing Co., Ltd., HMW-201B) was used to
Exposure was performed at mJ/car. At this time, in order to evaluate the photosensitivity, a negative film made so that the amount of light transmission decreases in stages (the first stage has an optical density of 0.05, and the optical density increases by 0.15 with each stage) A 21-step step tablet) was used.

The polyethylene terephthalate film was then removed and the unexposed areas were removed by spraying a 1% aqueous sodium carbonate solution at 30°C for 50 to 120 seconds. In addition, for samples whose unexposed areas cannot be removed even after spraying for 120 seconds, the evaluation of imageability in the 5th expression is set as × (
Other good samples were marked as ○). Furthermore, the photosensitivity of the photosensitive resin composition was evaluated by measuring the number of step tablets of the photocured film formed on the copper-clad laminate. The results are shown in Table 6. The photosensitivity is indicated by the number of steps on the step tablet, and the higher the number of steps on the step tablet, the higher the photosensitivity. Resolution indicates the minimum resolvable line width and interval in μm, and the smaller the number, the better the resolution.

Next, the developed material is subjected to alkali etching,
Thereafter, the alkali etching resistance was examined using two evaluation methods. First, in order to check the adhesion, we applied cellophane tape to the photocured film and quickly peeled it off in the vertical direction (90'
Beer-off test) The presence or absence of peeling of the photocured film was examined.

In addition, using an electron microscope, we observed the presence or absence of lifting of the photocured film (a phenomenon in which the copper foil and the photocured film are not in close contact with each other, there is a gap between them, and the photocured film appears to be lifted from the copper). The results are shown in Table 5. The alkaline etching was performed at 50° C. for 125 seconds using Process A manufactured by Miltex as the alkaline etching solution.

(a-2) A negative film having a rectangular opening (light transmitting part) of 5an x 7an was applied to the sample for characteristic evaluation (a-1,
), and developed in the same manner as (a-1). Next, the developed sample was immersed in a beaker containing a 2% aqueous sodium hydroxide solution at 50°C, and the resist (photocured film J) was peeled off, and the size of the peeled piece and the amount of peeling required to complete the peeling were measured. The completion time (seconds) was measured. Table 4 shows the evaluation criteria for the size of peeled pieces.

Table 4 (a-8) The sample for characteristic evaluation was exposed solidly (i.e. on the front) in the same manner as in (a-1) without applying a negative film. 100
mJ/ci) and then developed in the same manner as (a-1). Next, cross-cutting properties were evaluated using the JIS-5400 method.

The fifth evaluation criterion Shown in the table.

No. table cross cut Items with high evaluation scores for Possible Excellent porosity and adhesion.

(Note 1) Unexposed areas can be removed by spraying for less than 120 seconds...0 Unexposed areas cannot be removed by spraying for less than 120 seconds...× (Note 2) No lifting... ○ Slight lifting...△ Lifting...× From the results in Table 6, the photosensitive resin composition of the present invention has good adhesion to the base metal (copper (), good alkali etching resistance, It was found that the peelability and cross-cutting properties were excellent.

〔Effect of the invention〕

The multi-component copolymer produced by the production method of the present invention is suitable as a binder for photosensitive resin compositions, and photosensitive resin compositions containing this multi-component copolymer and photosensitive films using the same are , has good photosensitivity and resolution, and has low cold flow (also has excellent adhesion to metals, especially copper-clad laminates used for printed wiring boards, and has excellent peelability and flexibility). (Cross-cutting properties) are also good, and the alkali etching resistance is extremely excellent. It can also be suitably used in construction methods.

Claims (1)

[Claims] 1. General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [In the formula, R_1 represents a hydrogen atom or a methyl group, and R_2
represents an alkylene group or benzene ring having 1 to 8 carbon atoms] Monomers and general formula (II) ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (II) [In the formula, R_1 is the above-mentioned one] , R_3 represents an alkylene group having 1 to 5 carbon atoms, R_4 represents a hydrogen atom or a methyl group, and n represents an integer of 1 to 10]. A method for producing a multi-component copolymer, characterized by polymerizing in the presence of an agent. 2. Production of the multi-component copolymer according to claim 1, wherein the chain transfer agent is at least one selected from the group consisting of 2-ethylhexylthio-n-propionate, t-dodecylmercaptan, and trimethylolpropane trithiopropionate. Law. 3. A photosensitive resin composition comprising: (i) a multicomponent copolymer produced by the production method according to claim 1; (ii) a vinyl monomer; and (iii) a photoinitiator. 4. The photosensitive resin composition according to claim 3, wherein the multi-component copolymer has a weight average molecular weight of 10,000 to 500,000. 5. The photosensitive resin composition according to claim 3 or 4, wherein the multi-component copolymer has an acid value of 60 to 200 mgKOH/g. 6. A photosensitive element obtained by laminating the photosensitive resin composition according to claim 3, 4 or 5 on a support film.