JPH05216229A - Novel photopolymerizable composition - Google Patents

Abstract

PURPOSE:To enhance affinity and adhesiveness of the photopolymerizable composition to a substrate for forming a permanent circuit and to prevent its disconnection and the like by incorporating a polymer specified in its structural unit and its carboxylic group content and its average molecular weight and a photopolymerization initiator. CONSTITUTION:This photopolymerizable composition contains a mixture of the polymer having structural units each represented by the formula and the photopolymerization initiator. In the formula, n is an integer of 1-20; and each of R1 and R2 is H or methyl. The content of carboxylic groups is 200-700 in terms of the acid equivalent, and preferably, 300-600, and a molecular weight of 1X10<4>-2X10<5>, and the acid equivalent means the weight of the polymer having 1 equivalent of the carboxylic group. Such a photopolymerizable composition rapidly lowers in viscosity per prescribed temperature rise as compared with the composition using (meth) acrylate type polymers and causes no edge fusing during storage of a dry film resist, and has superior affinity and adhesiveness to a substrate.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to photopolymerizable compositions. More specifically, it relates to an alkali-developable photopolymerizable composition suitable for producing a printed circuit board.

[0002]

2. Description of the Related Art Conventionally, a so-called dry film resist (hereinafter abbreviated as DFR) composed of a support layer and a photopolymerization layer has been used as a resist for producing a printed circuit board.
The DFR is generally prepared by laminating a photopolymerizable layer made of a photopolymerizable composition on a support layer, and in many cases, further laminating a protective film on the composition.

In order to manufacture a printed circuit board using DFR, the protective film is first peeled off, and then the DFR is laminated on a substrate for permanent circuit preparation such as a copper-clad laminate. Next, the support layer is peeled off if necessary, and exposure is performed through a wiring pattern mask film or the like. When the support layer is present after the exposure, the support layer is peeled off if necessary, and the photopolymerizable layer in the unexposed portion is dissolved or dispersed by a developing solution to form a cured resist image on the substrate.

The process of forming a circuit after development is roughly divided into two methods. The first method is to further remove the resist after etching away the copper surface that is not covered by the cured resist, and the second method is to perform copper and solder plating treatment on the copper surface. After that, the resist is removed, and the exposed copper surface is etched.

In the manufacturing process of the printed circuit board, the process of laminating the DFR on the substrate is particularly important. In general, a substrate for producing a permanent circuit, such as a copper-clad laminate, has inevitably unevenness due to surface preparation, dents and groove-like scratches made during work. If the DFR is not sufficiently flexible, the DFR will not sufficiently follow these irregularities and scratches, and the substrate and DFR
Bubbles are taken in between and, as a result, inconveniences such as disconnection and short circuit of the circuit occur in the subsequent etching and plating steps. In recent years, due to finer circuits, DFR
The trackability of is becoming an even bigger problem.

On the other hand, some techniques for improving the followability by improving the laminating method have been disclosed. For example, lamination under vacuum (Japanese Patent Laid-Open No. 52-52703) and wet lamination (Japanese Patent Publication No. 1-43942).
Etc. On the other hand, the improvement of the DFR having high followability by changing the composition of the DFR is still insufficient. If a DFR having a higher followability can be obtained, it is not necessary to use the above-mentioned special laminating method, and the economic merit is large.

In order to further improve the followability of the conventional DFR, it is necessary to make the viscosity of the resist during heating during lamination lower than in the conventional case. When the viscosity of the resist is reduced when heated using the conventional composition, the followability to scratches and irregularities on the substrate is improved, but the viscosity at room temperature is also reduced, and the photopolymerization from the roll-shaped end surface during storage of DFR is performed. As a result of the exudation (edge fuse phenomenon) of the conductive resin layer becoming severe,
The unwinding of the laminated body and the deformation of the laminated body itself are not practical.

[0008]

As described above, in order to produce a printed circuit board which is becoming finer and finer in recent years with a high yield, a DFR having good storage stability at room temperature and good followability to a substrate is required. There is. An object of the present invention is to develop a DFR that meets this need.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above problems, a polymer obtained by reacting a part of the precursor polymer having a carboxyl group with an isocyanate having a photopolymerizable group is found. By using it, a photopolymerizable composition having good followability was successfully obtained, which led to the present invention. That is, the present invention includes (a) a structural unit represented by the following general formula (I), wherein the carboxyl group content is 200 to 700 in terms of acid equivalent.
And a polymer having a weight average molecular weight of 10,000 to 200,000.

[0010]

[Chemical 2] [Wherein, n is an integer of 1 or more and 20 or less, R ₁ and R ₂ are hydrogen or a methyl group] (b) A photopolymerizable composition comprising a photopolymerization initiator as an essential component.

A photopolymerization composition obtained by mixing a carboxyl group-containing polymer having the structural unit (I) and a photopolymerization initiator is surprisingly a conventional (meth) acrylic polymer. It was found that the viscosity sharply decreases with a certain temperature rise, as compared with the photopolymerizable composition using. Thereby, the DF using the photopolymerizable composition of the present invention
It was found that R did not cause an edge fuse during storage of DFR and exhibited good followability, as compared with the conventional photopolymerizable composition. Also, when an unsaturated compound or a conventional polymer is contained, a drastic viscosity change with respect to a temperature change occurs as compared with the conventional photopolymerizable composition, and D
It has been found that FR does not generate an edge fuse and has good followability.

The amount of carboxyl group contained in the polymer is 200 to 700, preferably 300 to 6 in terms of acid equivalent.
00. The molecular weight is 10,000 to 200,000, preferably 20,000 to 100,000. Here, the acid equivalent refers to the weight of the polymer having 1 equivalent of a carboxyl group therein. When the acid equivalent of the polymer is 200 or less, the compatibility with the coating solvent or other composition decreases, and when it is 700 or more, the developability and the peeling property decrease. Further, when the molecular weight is 200,000 or more, the developability is deteriorated, and when the molecular weight is 10,000 or less, the resistance to an etching solution or the like after photocuring is deteriorated. The acid equivalent amount is measured by potentiometric titration. The molecular weight is determined as a weight average molecular weight (in terms of polystyrene) by gel permeation chromatography (GPC). The polymer is obtained by reacting a part of the carboxyl groups of the precursor polymer having a carboxyl group with the monoisocyanate compound represented by the general formula (II).

[0013]

CH ₂ ═CR ₂ —CO—O— (CH ₂ ) _n —NCO (II) [wherein, n is an integer of 1 or more and 20 or less, R ₂ is hydrogen or a methyl group] The reaction is general. Following the reaction of the acid with the isocyanate, an amide bond is formed.

[0014]

Embedded image The -COOH + OCN- → -CONH- + CO ₂ ↑ polymer has an amide bond, and it is considered that a weak cohesive force due to a hydrogen bond acts only at a low temperature.

The acid equivalent of the precursor polymer is 100 to 600, preferably 200 to 500. The molecular weight is 10,000-2
It is 0,000, preferably 20,000 to 100,000. The amount of monoisocyanate reacted with the precursor polymer is 5 to 60 mol%, preferably 10 to 40 mol% based on the carboxyl groups contained in the precursor polymer. If the reaction amount is lower than 5 mol%, the effect of improving the followability cannot be obtained. When it is 60 mol% or more, the amount of carboxyl groups is small, so that the developability and the peeling property are deteriorated.

The reaction between the precursor polymer and the isocyanate can be obtained by stirring the precursor polymer solution and the isocyanate at room temperature under a nitrogen atmosphere. At that time, as a catalyst, a general catalyst having a high effect on the urethanization reaction, for example, triethylamine, triethylenediamine, iron acetyl acetate, tri-n-butyltin acetate, di-n-butyltin dichloride, di-n-butyltin dilaurate, etc. Are used alone or in combination of two or more.

The precursor polymer can be obtained by copolymerizing one or more of the following two types of monomers. The first monomer is a carboxylic acid having one polymerizable unsaturated group such as a carbon-carbon double bond in the molecule. For example, (meth) acrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, maleic acid half ester and the like. The second monomer is a non-acidic monomer having a polymerizable unsaturated group such as carbon-carbon double bond in the molecule, and develops the photopolymerizable layer, has resistance in etching and plating steps, and has a cured film. Are selected to retain various properties such as flexibility.

For example, there are alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and 2-hydroxyethyl (meth) acrylate. In addition, there are vinyl alcohol esters such as vinyl acetate, styrene, or a polymerizable styrene derivative. It is also possible that the second monomer contains a hydroxyl group or an amino group. When the obtained polymer is reacted with isocyanate, the isocyanate partially reacts not only with the carboxyl group but also with the hydroxyl group and amino group, but does not have a great influence on the resist performance and maintains the high follow-up property. ..

The photopolymerizable composition is photocurable even when only the polymer and the photopolymerization initiator are used. The amount of polymer is preferably in the range of 40 to 99.9% by weight, more preferably 60 to 95% by weight. Further, even when there is an unsaturated compound, it is photocured in the presence of an initiator. At this time, the amount of the polymer is preferably 10 to 99.9% by weight, more preferably 20 to 90% by weight. When the amount of the polymer is less than the lower limit, the cured image formed by exposure cannot have sufficient resist properties, for example, sufficient resistance in tenting, etching and various plating steps.

The photopolymerizable composition has the effect of improving the followability not only when the polymer of the present invention is used alone, but also when it is mixed with another polymer. The other polymer is the same as the above-mentioned precursor polymer, the acid equivalent is 100 to 600, and the molecular weight is 10,000 to 20.
It has many carboxyl groups. The photopolymerizable composition disclosed in the present invention contains a photopolymerization initiator as an essential component. The photopolymerization initiator here is various actinic rays,
For example, it is any known compound that is activated by ultraviolet rays and initiates polymerization.

For example, 2-ethylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-
Chloroanthraquinone, 2-chloroanthraquinone, 2
-Methyl anthraquinone, 1,4-naphthoquinone, 9,
Quinones such as 10-phenanthraquinone, 2-methyl-1,4-naphthoquinone, 2,3-dimethylanthraquinone, and 3-chloro-2-methylanthraquinone, benzophenone, Michler's ketone, 4,4'-bis ( Aromatic ketones such as diethylamino) benzophenone, benzoin, benzoin ethyl ether, benzoin phenyl ether, benzoin ethers such as methylbenzoin and ethylbenzoin, thioxanthone compounds and tertiary amines such as a combination of dimethylthioxanthone and dimethylaminobenzoic acid. There are also combinations with compounds, imidazole dimers.

The amount of the photopolymerization initiator contained in the photopolymerizable composition of the present invention is 0.01 to 30% by weight, preferably 0.05 to 10% by weight. Here, when the photopolymerization initiator is 30% by weight or more, the actinic ray absorption of the photopolymerizable composition becomes high, and curing of the bottom portion of the photopolymerizable layer by polymerization becomes insufficient when the photopolymerizable laminate is formed. Become. If it is less than 0.01% by weight, sufficient sensitivity cannot be obtained. The photopolymerizable composition according to the invention is photocurable even without a photopolymerizable unsaturated compound. When the unsaturated compound is contained, 1 to
The content is 50% by weight, but the range of 10 to 40% by weight is more preferable. When the unsaturated compound content is 50% by weight or more, high followability cannot be maintained.

In the present invention, one or more kinds of photopolymerizable unsaturated compounds may be used at the same time. Examples of the photopolymerizable unsaturated compound include 2-hydroxy-3-phenoxypropyl acrylate, phenoxytetraethylene glycol acrylate, and β-hydroxypropyl-β ′.
-(Acroyloxy) propyl phthalate, 1,4-
Tetramethylene glycol di (meth) acrylate,
1,6-hexanediol di (meth) acrylate,
1,4-cyclohexanediol di (meth) acrylate, octapropylene glycol di (meth) acrylate, glycerol (meth) acrylate, 2-di (p-
Hydroxyphenyl) propane di (meth) acrylate, glycerol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, polyoxypropyl trimethylolpropane tri (meth) acrylate, polyoxyethyl trimethylolpropane tri (meth) acrylate, di Pentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane triglycidyl ether tri (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, diallyl phthalate, polyethylene glycol di (meth) acrylate , Polypropylene glycol di (meth) acrylate, bis (polyethylene glycol (meth) acrylate) poly There is Russia propylene glycol and the like.

Examples of urethane reaction products of polyvalent isocyanate compounds such as hexamethylene diisocyanate and tolylene diisocyanate and hydroxy acrylate compounds such as 2-hydroxypropyl (meth) acrylate can be given. .. Thermal stability of the photopolymerizable composition,
In order to improve the storage stability, it is preferable that the photopolymerizable layer contains a radical polymerization inhibitor. For example, p-methoxyphenol, hydroquinone, pyrogallol, naphthylamine, tert-butylcatechol, cuprous chloride, 2,6-di-tert-butyl-p-
Cresol, 2,2'-methylenebis (4-ethyl-6)
-Tert-butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol)
Etc.

The photopolymerizable composition of the present invention may contain coloring substances such as dyes and pigments. For example, fuchsin, phthalocyanine green, auramine base, chalcoxide green S, paramagenta, crystal violet,
Methyl orange, Nile blue 2B, Victoria blue, malachite green, basic blue 20, diamond green and the like. Further, a color-forming dye that develops color upon irradiation with light may be contained. As a color-forming dye, a combination of a leuco dye and a halogen compound is well known. Examples of leuco dyes include tris (4-dimethylamino-2-methylphenyl) methane [leuco crystal violet] and tris [4-dimethylamino-2].
-Methylphenyl] methane [leucomalachite green] and the like.

On the other hand, as the halogen compound, amyl bromide,
Isoamyl bromide, isobutylene bromide, ethylene bromide, diphenylmethyl bromide, benzal bromide, methylene bromide, tribromomethylphenyl sulfone, carbon tetrabromide, tris (2,3-dibromopropyl) phosphate, trichloroacetamide, Amyl iodide, isobutyl iodide,
Examples include 1,1,1-trichloro-2,2-bis [p-chlorophenyl) ethane and hexachloroethane.

Further, the photopolymerizable composition may contain additives such as a plasticizer, if necessary. Examples thereof include phthalic acid esters such as diethyl phthalate. The second invention of the present invention comprises a photopolymerizable layer comprising the above photopolymerizable composition and a support layer. As the support layer for the photopolymerizable layer, a transparent layer that transmits active light is desirable.

As the supporting layer which transmits active light, a polyethylene terephthalate film, a polyvinyl alcohol film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyvinylidene chloride film, a vinylidene chloride copolymer film, a polymethylmethacrylate copolymer are used. Examples thereof include polymer films, polystyrene films, polyacrylonitrile films, styrene copolymer films, polyamide films and cellulose derivative films.
These films may be stretched if necessary.

In addition to the photopolymerizable layer laminated with the support layer, a protective layer may be laminated on the surface of the photopolymerizable layer, if necessary. An important characteristic of this protective layer is that the protective layer is sufficiently smaller than the support layer in terms of adhesion to the photopolymerizable layer and can be easily peeled off. Examples include polyethylene film and polypropylene film. Further, the film having excellent releasability disclosed in JP-A-59-202457 can be used. Although the thickness of the photopolymerization layer varies depending on the use, it is 5 to 100 μm, preferably 5 to 70 μm for producing a printed circuit board.
.mu.m, and the thinner the layer, the higher the resolution. Further, the thicker the film, the higher the film strength.

Next, the process for producing a printed circuit board using the photopolymerizable laminate of the present invention is in accordance with the prior art,
Briefly describe. First, if there is a protective layer, the protective layer is peeled off, and then the photopolymerizable layer is laminated on the metal surface of the printed circuit board substrate by thermocompression. The heating temperature at this time is generally 40 to 16
It is 0 ° C. Then, if necessary, the support layer is peeled off and imagewise exposed to actinic light through a mask film.

Next, if there is a support layer on the photopolymerizable layer after exposure, it is removed if necessary, and subsequently the unexposed portion is removed by development using an alkaline aqueous solution. As the alkaline aqueous solution, an aqueous solution of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide or the like is used. These can be selected according to the characteristics of the photopolymerizable layer, but 0.5% to 3% sodium carbonate aqueous solution is generally used.

Next, by development, the exposed metal surface is formed with an image pattern of metal by using a known method such as an etching method or a plating method. Thereafter, the cured resist image is generally peeled off with an alkaline aqueous solution which is stronger than the alkaline aqueous solution used in the development. The alkaline aqueous solution for peeling is not particularly limited, but an aqueous solution of 1% to 5% sodium hydroxide or potassium hydroxide is generally used. Further, it is possible to add a small amount of a water-soluble organic solvent to the developing solution or the stripping solution.

[0033]

EXAMPLES Specific examples of the present invention will be shown below by examples, but the present invention is not limited thereto.
Hiranuma reporting titrator C
It was performed by potentiometric titration with 0.1 N sodium hydroxide using OMTITE-7. The molecular weight was determined by gel permeation chromatography manufactured by JASCO Corporation. The viscosity of the photopolymerization layer is Shimadzu Flow Tester CFT-50.
Determined by 0A.

Synthesis Example 1 600 g of methyl ethyl ketone was placed in a 2 liter separable flask equipped with a stirrer, a reflux condenser and a thermometer.
220 g of methyl methacrylate as a polymerizable monomer, 100 g of methacrylic acid, 40 g of n-butyl acrylate, 40 g of 2-hydroxyethyl methacrylate, and 16 g of azobisisobutyronitrile as a polymerization initiator while stirring at 70 ° C. under a nitrogen stream. The homogeneous mixture of was added dropwise over 4 hours. After dropping, stir for 4 hours, and then at 80 ℃
The reaction temperature was raised and the mixture was stirred for 12 hours.

Upon cooling, a precursor polymer (P-1) for reacting with an isocyanate was obtained as a methyl ethyl ketone solution. The acid equivalent of this polymer was 342, and the weight average molecular weight was 50,000. 300 g of the precursor polymer was placed in a 1-liter separable flask equipped with a stirrer, 12 g of 2-methacryloyloxyethyl isocyanate (II) was stirred while stirring under a nitrogen stream, and a small amount of di-n-butyltin dilaurate as a catalyst. Add.

[0036]

Embedded image CH ₂ = C (CH ₃₎ was stirred _{COO-CH 2 CH 2 -NCO (} II) at room temperature for 24 hours to obtain polymer object (P-2) as a solution in methyl ethyl ketone. The disappearance of the isocyanate group was confirmed by IR. The acid equivalent weight was 488 and the weight average molecular weight was 50,000.

Synthesis Example 2 The starting monomers were 260 g of methyl methacrylate, 100 g of methacrylic acid and 40 g of n-butyl acrylate, and were synthesized in the same manner as in Synthesis Example 1. This precursor polymer (P-
The acid equivalent weight of 3) was 355, and the weight average molecular weight was 90,000. The desired polymer (P-4) was obtained by reacting 500 g of the polymer with 45 g of 2-methacryloyloxyethyl isocyanate. The acid equivalent weight was 476 and the weight average molecular weight was 90,000.

Example 1 The polymer P-2 prepared in Synthesis Example 1, the photopolymerization initiator, and other components were stirred for 12 hours at the component ratio shown in Table 1. Next, this mixed solution was uniformly applied to a polyethylene terephthalate film having a thickness of 20 μm using a bar coater, and dried in a dryer at 90 ° C. for 5 minutes to form a photopolymerizable laminate having a photopolymerization layer having a thickness of 50 μm. Was manufactured. Thereafter, a 35 μm polyethylene film was laminated on the surface of the photopolymerizable layer on which no polyethylene terephthalate film was laminated to obtain a laminated film.

This laminated film was subjected to the following follow-up test. [Follow-up test] Lamination-exposure-development-etching-resist peeling was performed on a copper-clad laminate having a 70-micron rolled copper foil laminated thereon in advance using a commercially available dry film resist to obtain a line width of 100, 110, 120, Thirteen
Linear grooves of 0,140,150μ were made. The depth of the groove was about 10μ.

The grooved substrate thus prepared was subjected to wet buff roll polishing (Scotch Bright HD # 60, manufactured by 3M Co., Ltd.).
After passing 0 or 2 times), the polyethylene film of the laminated film was peeled off, and the photopolymerization layer was laminated at 105 ° C. by a heating roll laminator. Through a mask film on the laminate, the line pattern so as to be perpendicular to the grooves of the substrate (line width: 125) were exposed at 80 mJ / cm ² by an ultra-high pressure mercury lamp (ORC Manufacturing HMW-201KB).

Then, after peeling off the polyethylene terephthalate film, a 1% sodium carbonate aqueous solution at 30 ° C. was sprayed for about 60 seconds to dissolve and remove the unexposed portion. Further, a cupric chloride solution at 50 ° C. was sprayed for about 120 seconds to etch the copper in the resist-free portion. Finally 50 ℃
Spray 3% aqueous sodium hydroxide solution for about 90 seconds,
The cured resist was peeled off.

On the copper line thus produced, the case where the grooved portion was previously etched and there was no disconnection was designated as ◯ because the followability of the laminated film was good. On the contrary, the case where the wire was etched and disconnected was regarded as insufficient tracking and marked with x. With respect to the total number of the grooved portions on the copper line, the ratio of x was taken as the disconnection rate (%), and the respective laminated films were compared.

Next, the storability of the laminated film with respect to the edge fuse at room temperature was examined by an accelerated test (press flow test) [Press flow test] The resist was cut into 1 inch squares, the polyethylene film was peeled off, and two 20 μm thick films were peeled off. Sandwiched between polyethylene terephthalate films. This sample was sandwiched between press plates heated to 25 ° C. and pressed under a load of 100 kg / cm ² for 5 minutes. After releasing the press, the protrusion widths of the photopolymerizable layers protruding from the four sides were measured with an optical microscope, and the average value was obtained. The protruding width corresponds to the ease with which the edge fuse of the laminated film comes out.

Separately, the storability of the laminated film at room temperature with respect to the edge fuse was accelerated in the same form as the product (roll storage test). [Roll storage test] The laminated film having a width of 330 mm was 8 mm in diameter.
A 3 mm plastic cylinder was wound 100 m with a tension of 15 kg / m. Roll this roll in the dark at 35 ° C and 65
% Environment. The end face of the roll was observed every day, and the gloss state of the end face due to the exudation of the photopolymerization layer was examined. The shorter the number of days of storage when the gloss starts to appear, the poorer the storage stability of the laminated film at room temperature and the more difficult it is to work during use.

Further, in order to examine the flow characteristics of the photopolymerization layer in the laminated film at each temperature, the viscosity was measured by a flow tester (flow test) [Flow test] The polyethylene film and the polyethylene terephthalate film were peeled from the laminated film,
Heating only the photopolymerization layer under constant pressure (20 kg /
extruded through a small diameter hole (1mmφ × 1mmL) in cm ² double). The temperature condition was a constant temperature rise of 2 ° C./min.

Comparative Example 1 The polymer P-1 prepared in Synthesis Example 1, the photopolymerization initiator, and other components were mixed in the component ratios shown in Table 1. Example 1
It was made into a dry film in the same manner as above and subjected to four evaluations.

Example 2 The polymer P-4 prepared in Synthesis Example 2, the photopolymerization initiator, and other components were mixed in the component ratios shown in Table 1. Example 1
It was made into a dry film in the same manner as above and subjected to four evaluations.

Comparative Examples 2 to 3 The polymer P-3 prepared in Synthesis Example 2 was mixed with the photopolymerization initiator and other components in the component ratios shown in Table 1. Example 1
It was made into a dry film in the same manner as above and subjected to four evaluations.

Example 3 The polymer P-2 produced in Synthesis Example 1, the polymer P-3 produced in Synthesis Example 2, the photopolymerization initiator, and other components were mixed in the component ratios shown in Table 1. .. A dry film was prepared in the same manner as in Example 1 and subjected to four evaluations. The evaluation results are summarized in Table 2. P, which is a polymer obtained by reacting an isocyanate
-2 and P-4 only in the case of a laminated film,
A laminated film having a low disconnection rate and less likely to cause an edge fuse was obtained. This laminated film has a sufficiently high viscosity at low temperature (40 ° C), but at high temperature (100 ° C)
The viscosity was very small.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

EFFECT OF THE INVENTION DFR using the photopolymerizable composition of the present invention
Has good followability with respect to a substrate for producing a permanent circuit such as a copper-clad laminate, so that during the etching or plating process,
Circuit breaks and shorts are significantly reduced. As described above, the DFR using the photopolymerizable laminate of the present invention is extremely useful as a resist for producing a printed circuit board.

Claims (1)

[Claims] 1. (a) It has a structural unit represented by the following general formula (I) and has a carboxyl group content of 2 in terms of acid equivalent.
A polymer having a weight average molecular weight of 10,000 to 200,000 [Wherein, n is an integer of 1 or more and 20 or less, R ₁ and R ₂ are hydrogen or a methyl group] (b) A photopolymerizable composition comprising a photopolymerization initiator as an essential component.