JPH0519473A - Crosslinked curing resin - Google Patents

Abstract

PURPOSE:To obtain the crosslinked curing resin for a solder resist which can be developed by an alkaline developer and is excellent in various kinds of the performance of a cured film by using a specific photosensitive resin compsn. and further, curing the resin to >=5H pencil hardness in the stage after the final curing. CONSTITUTION:The photosensitive resin consisting of (a) 40 to 70 pts.wt. copolymer of 15 to 30wt.% carboxylic acid type monomer, 2 to 25wt.% styrene type monomer expressed by formula I, 10 to 40% acrylate type monomer, and 30 to 65wt.% methacrylate type monomer, (b) 25 to 60 pts.wt. crosslinkable monomer mixture contg. 20 to 80wt.% compd. expressed by formula II and having >=1.3 pieces in average of ethylenic unsatd. groups in one molecule and (c) 0.01 to 10 pts.wt. photopolymn. initaitor is cured to >=5H pencil hardness. In the formula, R<1> denotes hydrogen, an alkyl group having 1 to 6 pieces of carbon atoms; R<2> denotes hydrogen or methyl group; R<3> denotes an alkyl group having 1 to 8 pieces of carbon atoms.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cross-linking cured resin for a solder resist used on a printed wiring board having a wiring pattern formed thereon.

[0002]

2. Description of the Related Art Conventionally, a solder resist (solder mask) has been widely used as a permanent protective film for printed wiring boards in the printed wiring board manufacturing industry. The solder resist is
It is used for the purpose of preventing solder bridges during soldering, preventing corrosion of conductors during use, and maintaining electrical insulation. As is clear from this purpose of use, since the solder resist is used under severe conditions, performance under the severe conditions described below is required.

(A) Retaining adhesiveness during solder immersion (240 to 280 ° C.), (b) Permanently retaining adhesiveness,
(C) Excellent resistance to solvents, chemicals, etc. (d) Retention of high electric insulation under high humidity conditions. To meet these requirements, thermosetting inks or photocurable inks are screen printed than before. Therefore, a method of forming a solder resist has been widely used. However, with the recent increase in the density of printed wiring, the solder resist formation by the screen printing method has been unable to cope with the problems of accuracy and thickness.

That is, in the screen printing method, there is a limit to the improvement in accuracy due to the problems of positional displacement due to the elongation of the screen mesh, ink "bleeding" and "blurring", and on the other hand, if the accuracy is attempted to be increased. Since there is an inherent contradiction that the film thickness becomes thin, it was not possible to obtain a thick film with high accuracy by the screen printing method.

For this reason, in recent years, instead of the screen printing method,
The photoresist method is being adopted. In this photoresist method, after forming a photosensitive resin film on a substrate, the photosensitive resin film is cured by selective exposure, and then the uncured portion is removed by a developing process. Particularly, in terms of accuracy. It is extremely superior to the screen printing method.

Several proposals have been made to date regarding the method of forming a photosensitive resin film by the photoresist method. For example, JP-A-51-15733 discloses that
A method of forming a photosensitive resin film by applying a photosensitive resin as a solution of an organic solvent on a substrate and then volatilizing the solvent by heat is disclosed. However, this method has problems that it is not possible to perform tenting on a small-diameter through hole that is not used for soldering components, and that the film thickness on the pattern cannot be sufficiently secured.

Therefore, a dry film resist as proposed in Japanese Patent Laid-Open No. 54-1018 is used,
It has been considered that a preferable method is to perform thermocompression bonding under reduced pressure as proposed in JP-A-52-52703. However, there has not yet been obtained a product that can be developed with an alkaline developer in the pattern formation stage and that the final cured product sufficiently satisfies the required performance as a solder resist, such as adhesion, surface hardness and heat resistance.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a cross-linking curable resin for a solder resist, which can be developed with an alkaline developer and which has various properties of a cured film.

[0009]

Means for Solving the Problems As a result of intensive studies for achieving the above-mentioned object, the present inventors have used a specific amount of a styrene type monomer as a copolymerization component of a thermoplastic polymer for a binder, and By using a photosensitive resin composition using N-alkoxymethyl (meth) acrylamide in a crosslinkable monomer mixture, and further curing the pencil hardness to 5H or more at a stage after final curing, excellent performance can be obtained. It has been found that a crosslinked cured resin is obtained.

That is, the present invention relates to (a) first polymerizable substances 15 to 3 which are composed of one or more compounds of an α, β-unsaturated carboxyl group-containing monomer having 3 to 15 carbon atoms.
0% by weight, general formula (I)

[0011]

[Chemical 3] (Wherein R ¹ represents hydrogen, an alkyl group having 1 to 6 carbon atoms) and a second polymerizable substance composed of one or more compounds selected from the group consisting of ring-substituted derivatives thereof. Third polymerizable substance 1 comprising 2 to 25% by weight of one or more compounds selected from the group consisting of alkyl acrylates in which the alkyl group has 1 to 8 carbon atoms
Fourth polymerizable substance 30 to 6 consisting of 0 to 40% by weight, and one or more compounds selected from the group consisting of alkyl methacrylates in which the alkyl group has 1 to 8 carbon atoms.
5 to 50% by weight of a thermoplastic polymer for a binder obtained by copolymerizing 5% by weight, (b) 20 to 80% by weight of the compound represented by the general formula (II), and averaging in one molecule. 25 to 60 parts by weight of a crosslinkable monomer mixture having 1.3 or more ethylenically unsaturated groups,

[0012]

[Chemical 4] (Wherein R ² represents hydrogen or a methyl group, R ³ represents an alkyl group having 1 to 8 carbon atoms) and (c) 0.01 to 10 parts by weight of a photopolymerization initiator as a main component. , A cross-linking curable resin having a pencil hardness of 5H or more, which is obtained by curing a photosensitive resin composition in which the total amount of components (a) to (c) is 100 parts by weight.

[0013]

The present invention will be described in more detail below.

In the thermoplastic polymer (a) for the binder which constitutes the photosensitive resin composition used in the present invention, 3 is added so that it can be developed with a dilute aqueous alkali solution such as sodium carbonate.
One or more kinds of α, β-unsaturated carboxyl group-containing monomers having ˜15 carbon atoms as the first polymerizable substance, 1
It is necessary to copolymerize at a ratio of 5 to 30% by weight.

Α, β-in the thermoplastic polymer for the binder
When the amount of the unsaturated carboxyl group-containing compound is less than 15% by weight, it cannot be developed with an alkaline developer or, even if it can be developed, an extremely long development time is required. on the other hand,
If it exceeds 30% by weight, the water absorption of the cross-linked cured resin after curing becomes large, and the electrical insulating property under high humidity conditions is significantly reduced.

Examples of the first polymerizable substance (carboxylic acid type monomer) include acrylic acid, methacrylic acid, cinnamic acid, crotonic acid, sorbic acid, itaconic acid, propiolic acid, maleic acid and fumaric acid. And these half-esters or anhydrides can also be used. The most preferred of these are acrylic acid and methacrylic acid.

The thermoplastic polymer (a) for binder of the present invention has the general formula (I) for the purpose of imparting solvent resistance and high electrical insulation under high humidity to the crosslinked cured resin after curing.

[0018]

[Chemical 5] (Wherein R ¹ represents hydrogen, an alkyl group having 1 to 6 carbon atoms) and a second polymerizable substance composed of one or more compounds selected from the group consisting of ring-substituted derivatives thereof. Is polymerized with 2 to 25% by weight.

When the copolymerization amount of the compound of the general formula (I) is less than 2% by weight, the solvent resistance of the crosslinked cured resin after curing and the electric insulating property under high humidity are deteriorated. On the other hand, when the copolymerization amount exceeds 25% by weight, the time required for the development using the alkali developing solution becomes significantly long, which is in the industrially unusable range.

Examples of the substituents on the benzene ring of the compound represented by formula (I) include nitro group, alkoxy group, acyl group, carboxyl group, sulfone group, hydroxyl group and halogen, and the number of substituents is Any of up to 5 may be used. Preferred substituents are methyl, t-
A single alkyl group such as a butyl group, and styrene is most preferable as the compound represented by the general formula (I).

The third polymerizable substance contained in the thermoplastic polymer (a) for binder is at least one kind of alkyl acrylate having an alkyl group having 1 to 8 carbon atoms.

The third polymerizable substance (acrylate type component) is added to the thermoplastic polymer for binder in an amount of 10 to 40% by weight in order to impart appropriate flexibility to the photosensitive resin composition used in the present invention. It is necessary to copolymerize it so that it is preferably in the range of 15 to 35% by weight. If the content of the acrylate-type component is less than 10% by weight, a sufficiently flexible dry film resist cannot be obtained, resulting in poor adhesion to the base material and embedding of the dry film resist in the unevenness of the base material surface. descend. On the other hand, if the copolymerization amount of the third polymerizable substance exceeds 40% by weight, the resist is too soft and the resulting dry film resist is rolled up between rolls and stored when the resist resin is removed from between the support films. This causes so-called cold flow development that oozes out with time, and also causes a decrease in solvent resistance of the crosslinked cured resin after curing.

Examples of these compounds include methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate and the like. .. The most preferred of these compounds are methyl acrylate, ethyl acrylate, n-propyl acrylate and 2-ethylhexyl acrylate.

The fourth polymerizable substance constituting the thermoplastic polymer for binder (a), together with the acrylate-type component (third polymerizable substance), has an appropriate Tg (glass transition temperature) for the thermoplastic polymer for binder. It is copolymerized to give, and is at least one kind of alkyl methacrylate having an alkyl group having 1 to 8 carbon atoms.

These fourth polymerizable substances (methacrylate type components) are contained in the thermoplastic polymer for binder in an amount of 30 to 6
It is necessary to perform copolymerization in the range of 5% by weight, preferably 35 to 65% by weight.

Examples of these compounds are butyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate.
Butyl methacrylate, 2-ethylhexyl methacrylate and the like can be mentioned. The most preferred of these compounds is methyl methacrylate.

The thermoplastic polymer (a) for binder preferably has a weight average molecular weight of 50,000 to 200,000. When the weight average molecular weight is less than 50,000, cold flow development is likely to occur when it is used as a dry film resist, and the weight average molecular weight is 20.
If it exceeds 50,000, the solubility of the unexposed area in an alkaline developer is insufficient, the developability is poor, the developing time is too long, the resolution is lowered, and the circuit pattern productivity is lowered. It tends to be.

The thermoplastic polymer for binder (a) used in the present invention is contained in an amount of 40 to 70 parts by weight per 100 parts by weight of the photosensitive resin composition. When the content of the thermoplastic polymer for binder is less than 40 parts by weight, the film forming property of the photosensitive layer of the obtained dry film resist is impaired and sufficient film strength cannot be obtained, causing cold flow. Easy and has low heat resistance. On the other hand, if the content of the thermoplastic polymer exceeds 70 parts by weight, the solvent resistance decreases.

The photosensitive resin composition used in the present invention is
Although it contains a crosslinkable monomer mixture as the component (b), 20 to 80% by weight of the crosslinkable monomer mixture is
The following general formula (II)

[0030]

[Chemical 6] (Wherein R ² represents hydrogen or a methyl group, and R ³ represents an alkyl group having 1 to 8 carbon atoms)
It must consist of alkoxymethyl (meth) acrylamide.

When this N-alkoxymethyl (meth) acrylamide is used in combination with a thermoplastic polymer for a binder containing a styrene type monomer (second polymerizable substance),
It is possible to obtain a cured product for a solder resist, which has a high degree of heat-resistant adhesion and a high degree of electrical insulation under high temperature and high humidity, which could not have been predicted by conventional knowledge.

When the content of the N-alkoxymethyl (meth) acrylamide type monomer is less than 20% by weight, the above effect cannot be sufficiently exerted, while 8
If it exceeds 0% by weight, the solvent resistance after curing is lowered.

Examples of the N-alkoxymethyl (meth) acrylamide represented by the general formula (II) include N-methoxymethyl (meth) acrylamide, N-ethoxy (meth) acrylamide, Nn-propoxy (meth) acrylamide. , N-i-propoxy (meth) acrylamide, Nn-butoxy (meth) acrylamide, N-i
-Butoxy (meth) acrylamide, Nt-butoxy (meth) acrylamide, Nn-hexyloxy (meth) acrylamide, N-2-ethylhexyloxy (meth) acrylamide and the like can be mentioned.

In order to ensure the solvent resistance of the crosslinked cured resin, the crosslinkable monomer mixture has an average of 1.3 per molecule.
It is necessary to have at least one ethylenically unsaturated group. Therefore, the crosslinkable monomer used in combination with the N-alkoxymethyl (meth) acrylamide represented by the general formula (II) is a crosslinkable monomer having two or more ethylenically unsaturated groups in one molecule. It is necessary to use the body.

The crosslinkable monomer having two or more ethylenically unsaturated groups in one molecule is, for example, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,3-butanediol di. (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2,2-bis [4- (meth) acryloyloxypolyethoxyphenyl] propane,
2,2-bis [4- (meth) acryloyloxypolypropyleneoxyphenyl] propane, hydroxypivalic acid neopentyl glycol di (meth) acrylate,
Glycerin di (meth) acrylate, glycerin tri (meth) acrylate, trimethylolethane di (meth) acrylate, trimethylolethane tri (meth)
Acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane tris [ethoxy (meth) acrylate], trimethylolpropane tris [propyleneoxy (meth) acrylate], trimethylolpropane tris [ Polyethoxy (meth) acrylate], trimethylolpropane tris [polypropyleneoxy (meth) acrylate], isocyanuric acid triethylol di (meth) acrylate, isocyanuric acid triethylol tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri ( (Meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate Poly (meth) acrylates, epoxy (meth) acrylates and urethanes of polyhydric alcohols such as Examples thereof include (meth) acrylates, and these can be used alone or in combination.

Within the range in which the average amount of ethylenically unsaturated groups in the crosslinkable monomer mixture is maintained at 1.3 or more in one molecule, one ethylenically unsaturated group per molecule is used. You may use the monomer which has. Examples of such a monomer include phenoxyethyl (meth) acrylate, phenoxydiethoxy (meth) acrylate, 3-phenoxy-2-hydroxypropyl (meth) acrylate,
Methoxytriethoxy (meth) acrylate and the like can be mentioned.

The crosslinkable monomer mixture (b) used in the present invention is the photosensitive resin composition 100 used in the present invention.
The content is 25 to 60 parts by weight, preferably 25 to 45 parts by weight. When the content of the crosslinkable monomer mixture is less than 25 parts by weight, the photosensitive resin composition is not sufficiently cured by light and the solvent resistance is lowered, while the content of the crosslinkable monomer mixture is 60%. If a large amount of the dry film resist is used in excess of parts by weight, cold flow is likely to occur and solvent resistance is also reduced.

As the photopolymerization initiator (c) for photopolymerizing the photosensitive resin composition used in the present invention, benzophenone, Michler's ketone, 4,4-bis (diethylamino) benzophenone, t-butylanthraquinone, 2
Known ones such as -ethylanthraquinone, thioxanthones, benzoin alkyl ethers and benzyl ketals can be used, and these can be used alone or in combination.

The photopolymerization initiator used in the present invention is
0.1 to 10 parts by weight is contained in 100 parts by weight of the photosensitive resin composition. If it is less than 0.1 part by weight, it is not sufficiently photo-cured, while if it exceeds 10 parts by weight, it becomes thermally unstable.

The photosensitive resin composition used in the present invention includes
It is preferable to contain tetrazole or its derivative in order to further improve the adhesion to the metal surface. Tetrazole or its derivative can improve adhesion to a metal surface by adding a small amount, and as an example thereof, 1-
Phenyltetrazole, 5-phenyltetrazole, 5
-Aminotetrazole, 5-amino-1-methyltetrazole, 5-amino-2-phenyltetrazole, 5-
Examples thereof include mercapto-1-phenyltetrazole and 5-mercapto-1-methyltetrazole.
More than one species can be used together.

The amount of tetrazole or its derivative used is preferably 0.005 to 5 parts by weight based on 100 parts by weight of the total amount of the binder resin, the crosslinkable monomer mixture and the photopolymerization initiator. If it is less than 0.005 parts by weight, the improvement of the adhesion to the metal surface is not clearly recognized, while if it exceeds 5 parts by weight, it takes a long time to dissolve it and the sensitivity of the photosensitive resin composition is also lowered. ..

Compounds other than the above tetrazoles such as benzotriazole and benzimidazole can also be used as adhesion promoters.

The photosensitive resin composition used in the present invention may optionally contain components such as a thermal polymerization inhibitor, a dye, a plasticizer and a filler.

In order to obtain the crosslinked cured resin which is the object of the present invention, the above specific photosensitive resin composition is used, and the curing is sufficient so as to give a pencil hardness of 5H or more at the stage after the final curing. It is necessary to proceed to. That is,
Adhesion to the base material required as a solder resist only after curing proceeds until the pencil hardness reaches 5H or higher,
Solder heat resistance and solvent resistance can be secured. On the other hand, pencil hardness is 5
In the cured state below H, various performances required as a solder resist cannot be satisfied even if the above-mentioned photosensitive resin composition is used.

As a method for sufficiently promoting the curing so that the pencil hardness is 5H or more, various methods known in the field of paints and the like can be used. Examples of methods that can be used include ultraviolet irradiation, electron beam irradiation, heat treatment and the like. These can be carried out singly or in combination of two or more kinds, and the method which can be carried out industrially easily and which is most effective is a combination of ultraviolet irradiation and heat treatment.

The irradiation with ultraviolet rays is effective in sufficiently promoting the addition reaction of the ethylenically unsaturated group, and can be carried out by using, for example, a high pressure mercury lamp. As the ultraviolet irradiation energy at this time, when it is preferably used in a range of ^{0.5J / cm 2 ~10J / cm 2} , the temperature of the substrate and the solder resist by ultraviolet irradiation is excessive rise ,
Irradiation is preferably divided into several times.

On the other hand, heating is effective in alleviating strain due to polymerization shrinkage. As a heating method, for example, far-infrared heating, a heating furnace, or the like can be used, but when a heating furnace is used, it is preferably performed in the range of 100 ° C. to 180 ° C. for 2 hours or less.

To form a crosslinked cured resin for a solder resist using the photosensitive resin composition used in the present invention,
First, a photosensitive layer made of a photosensitive resin composition is formed on a substrate. As the method for forming the photosensitive layer, a method of applying the photosensitive resin composition as an organic solvent solution and then volatilizing the solvent as described above, and a dry film resist sandwiching the photosensitive resin composition between two films Then, there are two types of methods in which one film is peeled off and then thermally pressed, but the method using a dry film resist is industrially preferable. Further, in thermocompression bonding of the dry film resist, it is more preferable to perform thermocompression bonding under a reduced pressure condition in order to further improve the conformability to the uneven surface due to the wiring pattern.

Next, the photosensitive layer is exposed to form a pattern. As the exposure method, various known methods can be used, and for example, an ultraviolet exposure method, a visible light exposure method, a laser exposure method or the like can be used, and as a method for selectively performing the exposure Can use a method using a photomask, a direct imaging method, or the like.

Next, the uncured portion (unexposed portion) is removed using an alkali developing solution. As the alkaline developer, for example, an aqueous solution of sodium carbonate, an aqueous solution of sodium phosphate, an aqueous solution of potassium carbonate can be used, and a small amount of a defoaming agent or a surfactant can be added to these aqueous solutions. Further, as a removing method, a spray method is most commonly used, but a part thereof can be replaced by a dipping method.

[0051]

EXAMPLES The present invention will now be described in more detail by way of examples. Synthesis example [Synthesis of thermoplastic polymer for binder] 1000 ml equipped with nitrogen inlet, stirrer, condenser and thermometer
100 ml of isopropyl alcohol, 100 g of methyl ethyl ketone and 200 g of the mixture of the monomers shown in Table 1 were added to a four-necked flask under a nitrogen atmosphere, and the temperature of the water bath was raised to 80 ° C. with stirring. Next, 1.0 g of asobisisobutyronitrile was dissolved in 10 g of isopropyl alcohol and added, and the mixture was polymerized for 4 hours. Then, 1.0 g of azobisisobutyronitrile dissolved in 10 g of isopropyl alcohol was added every 30 minutes in 5 batches, and then the temperature inside the flask was raised to the boiling point of the solvent for 2 hours at that temperature. Polymerized. After the completion of the polymerization, 100 g of isopropyl alcohol was added and the polymerization reaction product was taken out from the flask to prepare a thermoplastic polymer solution for a binder. The polymerization rate of the monomer mixture in each composition was 99.5% or more. In addition, the solid content in the thermoplastic polymer solution for binder is 3
It was 8.7%.

[0052]

[Table 1] [Preparation of Alkali Developable Dry Film Resist] Table 2
The thermoplastic polymer solution for the binder, the crosslinkable monomer mixture, the photopolymerization initiator and other components were added as described in 1. and sufficiently stirred to prepare a uniform solution of the photosensitive resin composition. The obtained composition was allowed to stand for 8 hours under reduced pressure to defoam, and then coated on a polyester having a thickness of 25 μm so that the thickness after drying would be 75 μm, and the resulting mixture was dried in a tunnel-type drying oven (4
1m in 0 ℃ × 3m, 60 ℃ × 3m, 90 ℃ × 3m)
The solvent was volatilized at a speed of / min, a 30 μm polyethylene film was further laminated thereon, both ends were slit, and a width of 300 mm and a length of 100 m were wound on a roll to prepare a dry film resist.

DFR- (a) to DFR- (g) are photosensitive resin compositions in the range used in the present invention, and DFR- (h) to DFR- (r) are in the range of the present invention. It is a photosensitive resin composition that is disengaged.

[0054]

[Table 2] Examples 1 to 9 and Comparative Examples 1 to 13 A crosslinkable cured resin was formed by the following method using the alkali developable dry film resist prepared by the method described in the preceding paragraph, and its performance was evaluated.

Table 3 shows the DFR used, post-curing method, pencil hardness and performance evaluation results.

[0056]

[Table 3] [Test Printed Wiring Board] The following printed wiring board was used for performance evaluation as a solder resist.

-Copper through-hole double-sided board-Base material 1.6 mm glass epoxy-Copper pattern height, 55 μm-Wiring density, 2 through pins-A copper solid part of 5 cm x 5 cm or more. [Method of Forming Crosslinked Cured Resin] [Lamination] Using a vacuum laminator HLM-V570 (manufactured by Hitachi Capacitor Co., Ltd.), a dry film resist was laminated on the above printed wiring board under the following laminating conditions.

Substrate residual heat roller temperature 120 ° C. Heat shoe temperature 100 ° C. Laminating pressure (cylinder pressure) 5 kgf / cm ² Pressure in vacuum chamber 100 mmHg Laminating speed 0.8 m / min [Exposure] Both sides of substrate laminated with dry film resist Overlay the photomask for the solder resist, D
Using a FR exposure machine HTE-106 (manufactured by Hitec Co., Ltd.), a 25-step step tablet (Mitsubishi Rayon Co., Ltd.)
Exposure was performed so that 15 steps remained. [Development] Release the support film from the exposed substrate,
Spray development was performed with a 1% sodium carbonate aqueous solution at 30 ° C. on a conveyor type developing machine. The time during which the unexposed portion can be completely removed by development is shown in Table 2 as "minimum development time".

For the subsequent processing and evaluation, a product developed for 1.5 times the minimum development time was used. [Washing / Drying] The developed substrate was sprayed with city water at room temperature for 1 minute, the water on the substrate was removed with an air knife, and further dried at 70 ° C. for 5 minutes. [Post-curing] Post-curing was performed by any of the following methods (a) to (e). (B) Ultraviolet irradiation with a high-pressure mercury lamp, 1 J / cm ² ×
After 3 times, heat treatment at 150 ° C for 1 hour. (B) Ultraviolet irradiation by a high pressure mercury lamp, 1.
Conducted 4 times at 5 J / cm ² . (C) Heat treatment at 160 ° C. for 1.3 hours. (D) Ultraviolet irradiation by high pressure mercury lamp, 0.35J /
cm ² once. (E) No UV irradiation or heat treatment. [Evaluation Method] [Measurement of Pencil Hardness] The pencil hardness was measured according to the method described in JIS K5400, 6.14.

[Cold flow property] width 300 mm, length 1
The dry film resist wound on a 00 m roll was left in a dark place at 23 ° C. and 60% RH for 5 days, and the presence or absence of resin oozing (cold flow) from the end face was visually examined.

○: No cold flow ×: Cold flow [Holding property] The substrate after the formation of the cross-linking curable resin was observed with a stereoscopic microscope to check for the presence of air pockets between the cross-linking curable resin and the substrate. ..

◯ ... No air accumulation × ... Air accumulation [Adhesion] 100 pieces (2 × 10) of 2 mm squares are made with a cutter knife on the solder resist formed on copper, and one end of the tape is used as a substrate. The area of the solder resist remaining on the copper was examined after the film was kept perpendicular to the surface and was momentarily separated.

⊚: 95% or more remained ◯: 90% or more, less than 95% residual ×: Residual less than 90% [Solder heat resistance] A substrate on which a solder resist was formed was immersed in eutectic point solder at 260 ° C for 10 seconds. Then, the presence or absence of "blister" or "peeling" of the solder resist was examined.

◯ ... No swelling / peeling X: Swelling / stripping [Adhesion after soldering] The adhesion of the substrate after soldering as described above was examined by the same method.

⊚: 95% or more remains ∘: 90% or more and less than 95% residual × ... Residue less than 90% [solvent resistance] The substrate on which the solder resist is formed is dipped in methylene chloride at room temperature, and the " I checked for blister and peeling.

◎… 10 minutes immersion No blistering / peeling 〇… 5 minutes immersion No blistering / peeling ×… 5 minutes immersion Blistering / peeling [electrical insulation under high humidity conditions] IPC-SM840A, IPC-B- 25 After forming a solder resist on the multi-purpose test pattern, wiring was performed on the comb pattern B and 100 V DC was applied for 7 days under the condition of Class 3, and after 1 minute at an applied voltage of 500 VDC with an electrical insulation tester. The insulation resistance value was measured.

Class 3 conditions: 8 hours cycle, humidity 90% or more over the entire period 1 hour 45 minutes to increase from 25 ° C. to 65 ° C. 4 hours 30 minutes, constant at 65 ° C. 1 hour 45 minutes, 65 ° C. to 25 ° C. Temperature drop ◎ ... 5 × 10 ⁹ Ω or more ◯ ... 5 × 10 ^{8 to} 5 × 10 ⁹ Ω × ... less than 5 × 10 ⁸ Ω [Required development time] The number of seconds required in the development step with the alkaline developer. I asked from.

◎ ... less than 90 seconds ◯ ... 90 seconds to 120 seconds × ... 120 seconds or more

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H01L 21/027 H05K 3/28 D 6736-4E

Claims (1)

Claims: (a) A first polymerizable substance 15 to 15 comprising at least one compound of an α, β-unsaturated carboxyl group-containing monomer having 3 to 15 carbon atoms. 30% by weight of general formula (I) (Wherein R ¹ represents hydrogen, an alkyl group having 1 to 6 carbon atoms) and a second polymerizable substance composed of one or more compounds selected from the group consisting of ring-substituted derivatives thereof. 2 to 25% by weight, 10 to 40% by weight of a third polymerizable substance consisting of one or more compounds selected from the group consisting of alkyl acrylates in which the alkyl group has 1 to 8 carbon atoms, and 1 to 30% by weight of the alkyl group. 40-70 parts by weight of a thermoplastic polymer for a binder obtained by copolymerizing 30 to 65% by weight of a fourth polymerizable substance consisting of one or more compounds selected from the group consisting of alkyl methacrylates having 8 carbon atoms , (B) containing the compound represented by the general formula (II) in an amount of 20 to 80% by weight,
And 25 to 60 parts by weight of a crosslinkable monomer mixture having an average of 1.3 or more ethylenically unsaturated groups in one molecule, embedded image (Wherein R ² represents hydrogen or a methyl group, R ³ represents an alkyl group having 1 to 8 carbon atoms) and (c) 0.01 to 10 parts by weight of a photopolymerization initiator as a main component. , A cross-linking curable resin having a pencil hardness of 5H or more, which is obtained by curing a photosensitive resin composition in which the total amount of the components (a) to (c) is 100 parts by weight.