JPH04195052A - Photosetting resist composition and printing plate using same - Google Patents

Abstract

PURPOSE:To facilitate manufacture of a high-density printed circuit plate using a partly additive method by using a mixture of a multifunctional unsaturated compound being solid at room temperature, a multifunctional unsaturated compound being liquid at room temperature, a photopolymerization initiator, an epoxy agent and its hardener, and a melamine derivative. CONSTITUTION:A photosensitive solder resist ink for screen printing is prepared by putting a diallyl phthalate resin as the multifunctional unsaturated compound being solid at room temperature into a separable flask, adding an organic solvent, mixing and stirring them at about 80 - 100 deg.C for about 0.5 - 2hr to dissolve it, then cooling the solution to room temperature, mixing multifunctional acrylate as the multifunctional unsaturated compound being liquid at room temperature, the photopolymerization initiator, the epoxy agent and its hardener, and the melamine derivative, sufficiently stirring and mixing them, and kneading the mixture in 2 - 4 times with a 3-roll mill, thus permitting coatability, contact- exposability, developability, resistances to offset, alkali, plating, elution due to plating, and heat, and insulation property to be all enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photocurable resist composition and a printed circuit board using the same.

[Conventional technology]

For example, the UV exposure and development type resist used in conventional printed circuit board manufacturing includes the following:
No. 1, Special Publication No. 52-30969, Japanese Patent Publication No. 60-208
No. 377, JP-A-62-4390, JP-A-62-25
No. 3613 can be mentioned. Such a resist was mainly used in the method of manufacturing a printed circuit board shown in FIG. FIG. 2 shows a printed circuit board manufacturing method known as the subtract method, using a four-layer board as an example. In this process, starting material is a copper-clad laminate with an inner layer and copper foil laminated on the top and bottom surfaces, holes are drilled at predetermined positions, a catalyst is applied in the holes, and then electrolytic copper is applied to the entire surface including the through holes. Plating is applied, a predetermined circuit pattern is formed by etching, and finally a solder resist is applied. Until now, such solder resists have been made of thermosetting epoxy resins that form patterns by screen printing, but as the wiring density of printed circuit boards increases, UV exposure, which has better coating accuracy, and A developable solder resist was developed.

On the other hand, in the method for manufacturing printed circuit boards using the part-reactive method shown in FIG. It is essential to use a resist.

In the part-reactive method, unlike the subtract method, holes are drilled at predetermined positions in a copper-clad laminate, a catalyst is applied, and a conductor circuit is first formed. Next, a solder resist having plating reactivity resistance is formed at predetermined portions, and finally, chemical copper plating is used to plate only necessary portions such as through holes, lands, connectors, etc.

This manufacturing method is cheaper and cheaper than the subtract method.
It has the advantage of high precision. In other words, it does not plate the entire surface as in the subtract method, but only partially plates where it is needed, and it suffices to etch only the thin copper foil of the copper-clad laminate when forming conductor circuits. Therefore, the process is simple, there is little loss, and high-precision wiring is possible.

However, in order to take advantage of these advantages, the solder resist used in the Bartley deep dip method is required to have special functions. In other words, the copper wiring pattern under the solder resist is immersed in a harsh high-temperature, strong alkaline chemical copper plating solution for a long time, and the deposition potential of the chemical copper plating is -0.6.
~-(1,9V <see saturated calomel electrode) acts for a long time. Even after going through such a harsh process, it still maintains the properties such as the heat resistance required as a solder resist and the insulation required to protect printed circuit boards as a permanent resist.
This is an extremely advanced function that must not deteriorate.

As a solder resist having plating reactivity resistance suitable for such purposes, an epoxy resin-based thermosetting solder resist in which a pattern is formed by screen printing is known, and an example thereof is disclosed in JP-A-58-147416. ing. Also,
UV exposure and development type solder resists with plating reactivity resistance are also known, an example of which is disclosed in Japanese Patent Application Laid-open No. 62-26532.
It is disclosed in No. 1.

A UV exposure/development type solder resist having such plating reactivity resistance forms a UV exposure/development pattern, so it has extremely high precision and is suitable for manufacturing high-density printed circuit boards. However, in the mass production of plating large quantities of circuit boards, the resist contains dicyandiamide, so during the long chemical copper plating process, trace amounts of dicyandiamide dissolve into the chemical copper plating solution, causing problems with copper plating. This had a problem in that it had a serious effect on the precipitation state and deteriorated the reliability of through holes.

[Problem to be solved by the invention]

The purpose of the present invention is to realize a UV exposure and development type solder resist that has plating reactivity resistance without the drawbacks of the prior art described above, and to facilitate the production of high-density printed circuit boards using the padria day dip method. It is said that There are a wide variety of properties that a practical resist should have, and if even one of them is missing, its practicality will be significantly impaired. Therefore, the object of the present invention cannot be achieved simply by combining conventional techniques. The object of the present invention is to provide a resist composition that satisfies many properties at the same time. The issues to be solved for this purpose are listed below.

a) It is essential that the resist of the present invention does not contain dicyandiamide. In mass production where a large number of printed circuit boards are plated, if the resist contains dicyandiamide, a trace amount of dicyandiamide will dissolve into the chemical copper plating solution during the long chemical copper plating process, causing the copper plating to become precipitated. This has a significant impact and deteriorates the reliability of the through hole. Therefore, although the resist of the present invention contains dicyandiamide, it must simultaneously satisfy the following problems.

b) It is essential that the resist of the present invention be cured by exposure to UV light. That is, it is necessary to cause a crosslinking reaction by irradiating UV light (ultraviolet light) of 300 to 400 nm suitable for manufacturing printed circuit boards, and only the irradiated portions need to be cured. In addition, the practical irradiation amount is 0.02~IOJ/c.
It is desirable to cure within the range of m2.

C) The resist of the present invention has an appropriate difference in solubility in a developer between a portion cured by UV irradiation and an uncured portion;
It is essential that the resolution after development is good. In other words, it must have excellent developability with an appropriate solvent.

d) It is essential that the resist of the present invention can be applied to both sides of a printed circuit board and exposed simultaneously to both sides. That is, UV light exposed from one side is transmitted through the resist and the base material, and hardens the resist on the other side. So-called. There should be no bleed-through. Unless these issues are resolved,
Differences in the negative mask patterns used on both sides of the base material also appear on the opposite side, which significantly impairs practicality.

e) It is essential that the resist of the present invention can be exposed with a negative mask in close contact with the resist during UV exposure. If these issues are not resolved, the adhesiveness of Regis i itself,
The resist and negative mask adhere to each other due to the softening of the resist due to the rise in temperature during exposure. In this case, it becomes necessary to clean the negative mask after each exposure, which significantly impairs practicality.

r) It is essential that the resist of the present invention has good coating properties. In other words, when applying resist to one side of a printed circuit board using screen printing or a roll coater, it is necessary to have an appropriate viscosity characteristic as an ink so that the thickness is uniform and no voids remain. .

g) The resist of the present invention must be able to be coated on one side, pre-dried, and coated on the other side as well. If pre-drying is insufficient, it becomes impossible to print resist on the other side while the viscous resist remains applied on one side.

If the pre-drying is excessive, the reaction of the resist progresses, resulting in a difference in the properties of the resist on both sides. To avoid such problems, it is essential to be able to perform preliminary drying appropriately.

h) The resist of the present invention is formed on a printed circuit board as a product, and as a solder resist, it is essential that it has good heat resistance to withstand repeated soldering. That is, even after repeating solder dipping for 10 seconds at approximately 260°C approximately 10 times, or equivalently hot air,
It is essential that no abnormality such as blistering or peeling occurs in the resist on the printed circuit board even when soldering is performed using infrared rays, solvent vapor, or the like. It should be emphasized that such properties are required of the resist after undergoing the harsh chemical copper plating process.

i) The resist of the present invention is formed on a printed circuit board as a product, and it is essential that it can maintain high insulation properties. That is, it is necessary to be able to maintain excellent insulation properties that do not cause insulation deterioration between wirings, especially insulation properties when moisture is absorbed. It should be emphasized that such properties are required of the resist after undergoing the harsh chemical copper plating process.

j) The resist of the present invention is formed on a printed circuit board as a product, and it is essential that it has excellent chemical resistance. That is, in soldering used in the mounting process of mounting components on a printed circuit board, it is necessary that the resist is not dissolved or deteriorated by flux, cleaning solvent, or the like. It should be emphasized that such properties are required of the resist after undergoing the harsh chemical copper plating process.

k) It is essential that the resist of the present invention has good alkali resistance after being formed on a printed circuit board as a product. That is, since the resist undergoes a harsh chemical copper plating process, it is necessary that the resist does not dissolve or change in quality due to the high temperature, strong alkaline chemical copper plating solution.

i) It is essential that the resist of the present invention has good plating reactivity after being formed on a printed circuit board as a product. Specifically, such characteristics are as follows. When manufacturing printed circuit boards using the Bartley-dip method, it is essential that the resist on the conductor circuits does not peel off during the chemical copper plating process. The printed circuit board on which the resist has been formed is immersed in a harsh high-temperature, strong alkaline chemical copper plating solution for a long time, and the copper wiring pattern under the solder resist has a deposition potential of -0.6 to -.
0.9V works for a long time. Even after such a harsh process, there must be no reduction in adhesion or peeling at the interface between copper and resist.

Although the mechanism by which adhesion decreases and peeling occurs is not clear, we have found from experience that the deposition potential of chemical copper plating is the driving force for the peeling reaction, and that the presence of copper oxide at the interface between copper and resist causes significant peeling. It is known that it progresses rapidly. From these facts, the oxides at the interface between the circuit copper foil and the resist are electrochemically reduced by the chemical copper plating deposition potential, which destroys the bond between the copper and resist, which is the cause of adhesion, and causes peeling. I estimate that it is. Therefore, the plating reactivity (peeling resistance) is also a kind of cathode peeling resistance.

Such plating reactivity should be strictly distinguished from what is generally referred to as plating resistance. - What is generally referred to as plating resistance often refers to the above-mentioned alkali resistance, which is completely different from plating reactivity resistance (peeling resistance).

The problem of plating reaction resistance (peeling resistance) is one of the most important points to keep in mind when manufacturing printed circuit boards using the part-reactive method.If this problem is not resolved, the resist on the circuit copper foil will deteriorate. It peels off and becomes completely useless.

m) After the resist of the present invention is formed on a printed circuit board as a product, it is essential that harmful components are not eluted or extracted from the resist into the plating solution during the chemical copper plating process. If such plating elution resistance is not resolved, components eluted or extracted from the resist will have a negative effect on the copper plating precipitation reaction, resulting in the plating reaction stopping or delaying, or causing the deposited copper to deteriorate. Significantly deteriorates crystal orientation and physical properties. Therefore, the connection reliability of the through-holes of the printed circuit board, the solder wettability, and the connection reliability are reduced, and the method is completely impractical.

The mechanism by which harmful components adversely affect the deposition reaction of copper plating is extremely complex because the plating reaction involves a catalytic reaction of the reducing agent on the copper surface. It is necessary to ensure plating elution properties.

The problem of plating elution resistance is one of the most important points to keep in mind when manufacturing printed circuit boards using the Bartley-dip method.If this problem is not resolved, the manufactured printed circuit boards will not be practical at all. Not only is it lost, but the chemical copper plating solution is also contaminated, making it necessary to dispose of a large amount of plating solution, resulting in significant losses.

Furthermore, the plating elution resistance and the above-mentioned alkali resistance should be strictly distinguished. That is, if the alkali resistance is insufficient, the resist itself will dissolve in the alkali, whereas if the plating elution resistance is insufficient, only specific components in the resist will be eluted into the plating solution.

An object of the present invention is to provide a photocurable resist composition that satisfies all of the above-mentioned problems a) to m).

Another object of the present invention is to provide a printed circuit board using a photocurable resist composition that satisfies all of the above-mentioned problems a) to m).

[Means to solve the problem]

In order to achieve the above object, the present invention provides a photosensitive solder resist composition having plating resistance that includes a polyfunctional unsaturated compound that is solid at room temperature, a polyfunctional unsaturated compound that is liquid at room temperature, and a photopolymerizable A photocurable resist composition is used, which is characterized by containing an initiator, an epoxy resin, a curing agent for the epoxy resin, a melamine derivative, an antifoaming agent, a pigment, and an organic solvent.

The polyfunctional unsaturated compound that is solid at room temperature used in the present invention is a compound having a large number of unsaturated groups in the molecule, such as diallyl phthalate resin. , it is possible to obtain a resist that satisfies many of the above-mentioned problems at the same time.

Specifically, diallyl phthalate resin comprises a prepolymer of diallyl ester of ortho, iso, or terephthalic acid. Such a prepolymer is also called a β-polymer, and its detailed manufacturing method and properties are described, for example, in Naoki Yoshimi, "Diallyl Phthalate Resin," published by Nikkan Kogyosha (1962). It is also possible to obtain commercially available products from Daiso. Preferred prepolymers for use in the present invention have a molecular weight of about 30
If it is less than 3,000, the adhesion exposure property with a negative mask is poor, and if it is more than 30,000, it may hinder the developability. Furthermore, even when a prepolymer is used, it cannot be prevented that a small amount of diallyl phthalate monomer or γ-polymer having a three-dimensional linear structure that remains or is generated during the synthesis of the prepolymer is contained.

Furthermore, the photosensitive solder resist composition having plating resistance of the present invention contains a polyfunctional unsaturated compound that has at least two or more ethylene bonds in its molecule and is liquid at room temperature. The darkening compound is obtained, for example, by an esterification reaction between an unsaturated carboxylic acid and a polyhydroxy compound having a valence of 2 or more. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, etc., while examples of divalent or higher polyhydroxy compounds include ethylene glycol, diethylene glycol, trimethylolpropane, pentaerythritol, and divalent acid. Pentaerythritol and its derivatives can be mentioned.

Examples of compounds obtained by the esterification reaction between an unsaturated carboxylic acid and a polyhydroxylated metal include diethylene glycol diacrylate, polyethylene glycol diacrylate, neopentyl glycol diacrylate, 1.5bentanediol diacrylate, 1.
6 hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol tonoacrylate, diethylene glycol dimethacrylate,
1.3 Diacrylate, dimethacrylate, triacrylate compounds represented by butanediol dimethacrylate, tri, tetra, penta, hexaacrylate or methacrylate of dipentaerythritol, tri, tetra, penta, hexaacrylate or methacrylate of sorbitol, etc. Examples include polyfunctional acrylates and methacrylate compounds represented by , oligoester acrylates, and oligoester methacrylates.

Further, a compound produced by an addition reaction with an epoxy resin having a valence of 2 or more and an unsaturated carboxylic acid can also be used as a polyfunctional unsaturated compound that is liquid at room temperature. Examples of such compounds include polyfunctional unsaturated compounds that are liquid at room temperature and are produced by the addition reaction of bisphenol A type or novolak type epoxy resins with acrylic acid or methacrylic acid.

The number of functional groups contained in the molecule of the polyfunctional unsaturated compound is preferably as large as possible, and is at least 2 or more, preferably 3 or more, and more preferably 6 or more.

The above examples do not limit the addition of monofunctional unsaturated compounds, and mixtures with polyfunctional unsaturated compounds can also be used if necessary.

Furthermore, the photosensitive solder resist composition having plating resistance of the present invention contains a photopolymerization initiator.

Examples of photopolymerization initiators include acetophenone, benzophenone, Michler's ketone, benzyl, benzoyl, benzoin alkyl ether, benzoin alkyl ketal, thioxanthone, thioxanthone, anthraquinone, anthraquinone and its derivatives or analogues, 1-hydroxycyclohexylphenyl ketone and its derivatives. or analogs, α typified by 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propene-1
-aminoketone compounds and the like. If desired, mixtures of photoinitiators can be used. Furthermore, if necessary, it is also possible to use an amine compound or the like that sensitizes the action of the photopolymerization initiator.

Furthermore, the photosensitive solder resist composition having plating resistance of the present invention contains an epoxy resin.

Epoxy resins have an average of two or more epoxy groups per molecule, such as bisphenol A
1-halogenated bisphenol A1 Polyglycidyl ether or polyglycidyl ester, novolac type, obtained by reacting a polyhydric phenol such as catechol, resorcinol, or a polyhydric alcohol such as glycerin with epichlorohydrin in the presence of a basic catalyst. Examples include epoxy novolak obtained by condensing a phenol resin and epichlorohydrin, epoxidized polyolefin epoxidized by a peroxidation method, epoxidized polybutadiene, cisyglopentadiene oxide, and epoxidized vegetable oil.

Furthermore, the photosensitive solder resist composition having plating resistance of the present invention contains an epoxy resin curing agent. As curing agents for epoxy resins, amine compounds and imidazoles are suitable. Typical amine compounds include aliphatic compounds such as ethylenediamine, hexamethylenediamine, and l-diethylenetetramine, and aromatic compounds such as diphenylamine,
Typical examples include 4゜4゜-diaminodiphenylmethane and phenylenediamine. Among imidazoles, there are alkylimidazoles such as 2-methylimidazole, 2-ethyl-4-methylimidazole, and 2-phenylimidazole, and imidazole. Typical derivatives include purine, 2,6-diamitpurine, and 2-aminobenzimidazole, and derivatives obtained by the addition reaction of 2,4-diamino-6-vinyl-s-triazine and alkylimidazole. 2,4-diamino-6 (
2′-methylimidazole-(1′))ethyl-8-triazine, 2,4-diamino-6(2′-ethyl-4′-methylimidazole-(1′))ethyl-s-triazine, 2,4 -diamino-6(2′-undecylimidazole-(1″))ethyl-5-triazine, 2,4-
Diamino-6 (2′-phenylimidazole-(1′)
) Ethyl-8-triazine or 2,4-diamino-
6(2°-methylimidazole-(1°))ethyl-S
-triazine/isocyanuric acid adducts, etc. In addition, examples of other amine-based curing agents include boron trifluoride monoethylamine. Mixtures of amine curing agents can be used if desired. Particularly preferred is a compound obtained by an addition reaction between 2-vinyl-4,6-diamitsu-s-triazine and alkylimidazole from the viewpoint of resist storage stability and resist gelation during drying.

Furthermore, the photosensitive solder resist composition having plating resistance of the present invention contains a melamine derivative. This derivative contains one or more amino groups of melamine and/or
Alternatively, H of the amino group is substituted with a substituent having a photopolymerizable unsaturated bond such as agriloyl, methacryloyl, allyl, or vinyl bond. Specifically, 2,4-diamino-6-vinyl-s-h liazine, 2,4-diamino-6-(2-methacryloylethyl)-s-triazine, N(2), N(2)-diallylmelamine There are representative examples such as

Such a melamine derivative simultaneously reacts when the polyfunctional unsaturated compound is polymerized by exposure to light, and is incorporated into the three-dimensional skeleton of the cured polyfunctional unsaturated compound. Therefore, it is unlikely to be eluted into the plating solution during chemical copper plating and deteriorate the physical properties of the plated copper film.

Furthermore, the photosensitive solder resist composition having plating resistance of the present invention contains an antifoaming agent. As such an antifoaming agent, an organic silicon compound containing a siloxane bond, typified by silicone oil, is mainly used.

Furthermore, the photosensitive solder resist composition having plating resistance of the present invention contains a pigment. As such pigments, phthalocyanine, phthalocyanine green, phthalocyanine blue, etc., which are pigments having a phthalocyanine skeleton with excellent heat resistance, are mainly used.

Furthermore, the photosensitive solder resist composition having plating resistance of the present invention contains an organic solvent. As such organic solvents, methyl, ethyl, butyl cellosolve and its acetate, methyl, ethyl, butyl calpitol, etc., and high boiling point solvents such as terpineol are mainly used.

Furthermore, the performance of the photosensitive solder resist composition having plating resistance of the present invention can be further improved by adding other additives as necessary.

Such additives include thixotropic agents to adjust the viscosity of the resist, fillers to adjust the heat resistance of the resist, ultraviolet absorbers to adjust the resolution of the resist, and storage stability of the resist. Examples include polymerization inhibitors for adjusting the .

An example of such a thixotropic agent is ultrafine quartz powder, an example of such a filler is fine quartz powder, and an example of such an ultraviolet absorber is 4-t-butyl-4'-methoxy-di Benzoylmethane, 2-ethylhexyl-p-methoxycinnamate, 2-(2°-hydroxy-3°, 5′-
di-tert-butylphenyl)benzotriazole,
2-(2'-hydroxy-3'-tert-butyl-
5'-methylphenyl)-5-chlorobenzotriazole, 2-(2"-hydroxy-3',5'-diter
t-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3-(3'', 4'', 5
”, 6”-tetrahydrophthalimidomethyl)-5′
-methylphenyl)benzotriazole and the like. An example of such a polymerization inhibitor is hydroquinone or a derivative thereof.

The preferred blending ratio for constituting the composition of the present invention is 100 parts by weight of the polyfunctional unsaturated compound that is solid at room temperature, 5 to 30 parts by weight of the polyfunctional unsaturated compound that is liquid at room temperature, Preferably, the amount is 10 to 30 parts by weight, the photopolymerization initiator is 2 to 12 parts by weight, the epoxy resin is 5 to 40 parts by weight, and the curing agent for the epoxy resin is 0.1 to 5 parts by weight. The amount of the melamine derivative is 1 to 25 parts by weight, preferably 2 to 20 parts by weight, and the antifoaming agent is 0.5 parts by weight.
The amount of the pigment is 0.2 to 10 parts by weight, and the amount of the organic solvent is 50 to 100 parts by weight. If necessary, one compound may serve as both the curing agent for the epoxy resin and the melamine derivative.

The upper and lower limits of this blending ratio are the problems of the present invention (
A) to (m) were selected from carefully selected results so that they were all simultaneously satisfactory.

Next, a method of manufacturing a printed circuit board by a part additive method using the photosensitive solder resist composition having the above-mentioned plating resistance, which is the second object of the present invention, will be described in accordance with FIG. .

After making holes in the copper-clad laminate board [Fig. 1, ■)] using a method well known to those skilled in the art, a catalyst for chemical copper plating is applied to the entire surface of the board including the inside of the through holes [Fig. 1, 2)] .

Next, conductor circuits are formed on both sides of the board by etching the predetermined portions by a method well known to those skilled in the art [Fig. 1, 3)]
.

Next, the photosensitive solder resist composition having plating resistance of the present invention is applied to one side of the substrate including the conductor circuit, and the substrate coated with the resist is dried to solidify the resist.

This method is repeated on the back side, or a photosensitive solder resist composition having plating resistance is simultaneously applied to both sides of the substrate and then dried to form solidified resist layers on both sides of the substrate. Drying temperature is 60 to 10
At 0°C, the drying time is preferably 0.2 to 2 hours.

Next, a negative mask is brought into close contact with the solidified resist layers on both sides of the substrate, and UV light of 0.1 to 157 cm 2 is irradiated from both sides at the same time for exposure. Next, the negative mask is peeled off from the resist surface, and the unexposed areas are dissolved and removed by development. A nonflammable chlorinated solvent such as 1,1,1-trichloroethane is used as a suitable solvent for such development, and a development time of 0.5 to 5 minutes is selected.

Next, the substrate is heated to harden the patterned resist portion. The curing conditions were 120 to 18 (1°C, 0.
2 to 2 hours is selected.

Preferably, the heat-cured resist is irradiated with UV light again to promote curing of the resist.

A suitable exposure dose for such post-exposure is 1 to 10 J/cm2.

Through the above steps, a resist layer is formed on the substrate [
Figure 1, 4)].

Next, the board is immersed in chemical copper plating, and a thick chemical copper plating is applied only to the main parts such as inside the through-holes and on the lands, and a printed circuit board is manufactured by the Bartley-dip method. Figure 1, 5)]. The thickness of the copper plating is usually selected to be 10 to 40 μm. It is a particularly important advantage of the present invention that no peeling of the resist on the circuit copper foil occurs during such chemical steel plating.

In manufacturing a printed circuit board by the padria dip method as described above, the resist of the present invention can simultaneously satisfy all of the above-mentioned problems (a) to (m) of the present invention. This made it possible to manufacture high-density printed circuit boards using the Bartley-dip method.

〔Example〕

Hereinafter, the photosensitive solder resist composition having plating resistance of the present invention and the production of a printed circuit board using the same will be specifically explained. The photosensitive solder resist compositions used in the following Examples and Comparative Examples were manufactured in common by the following method.

The diallyl phthalate resin used in the present invention as a polyfunctional unsaturated compound that is solid at room temperature is weighed, placed in a separable flask, and the weighed organic solvent is added thereto, mixed, and then heated at 80 to 100°C for 30 minutes. Dissolve with stirring for 2 to 2 hours. After the melt is cooled to room temperature, the remaining resist material is added and mixed by thorough stirring. Next, the resist ink for screen printing is prepared by cross-wiring 2 to 4 times using a three-roll mill.

On the other hand, the manufacturing of printed circuit boards commonly follows the following method.

Glass epoxy double-sided copper-clad laminate with 1.6 mm thickness and 35 μm copper foil [first cause] 8) After drilling holes in the predetermined positions of the substrate, chemical copper plating catalyst was applied to the substrate including the inside of the through holes. [Fig. 1, 2)].

Next, using a dry film resist for etching, a predetermined portion is etched by a tenting method.
Conductor circuits were formed on both sides of the substrate [Fig. 1, 3)].

Next, the photosensitive solder resist ink prepared by the above method was applied by screen printing to one side of the substrate including the conductive circuit, and the substrate coated with the resist was dried to solidify the resist. Repeat this process on the back side. Solidified resist layers were formed on both sides of the substrate. Drying temperature is 80
℃, the drying time is 1 hour.

Next, negative masks were brought into close contact with the solidified resist layers on both sides of the substrate, and UV light of 0.5 J/cm2 was irradiated and exposed from both sides simultaneously. Next, the negative mask was peeled off from the resist surface, and the unexposed areas were dissolved and removed by development. As development and dissolution, 1. ]~Trichloroethane was used, and 1 minute was selected as the development time.

Next, the substrate was heated to harden the resist portion on which the pattern was formed. The curing conditions were 150°C for 1 hour.

Furthermore, 3 J/ctn was applied to the heat-cured resist again.
2 UV light was irradiated to accelerate curing of the resist.

Through the above steps, a resist layer is formed on the substrate (Fig. 1, 4)].

Next, the board was immersed in a chemical copper plating solution, and a thick chemical steel plating was applied only to the main parts, including inside the through holes and on the lands (Fig. 1, 5)].

A chemical steel plating solution with the following composition was used.

The plating conditions were a bath temperature of 70° C., a bath pH of 12.5, and a plating time of 15 hours. During this time, the plating solution components were automatically replenished so that the plating solution composition and plating conditions were always constant. The deposition potential was about -0.7V (reference to saturated calomel electrode), and the plating thickness was about 30 μm.

Composition of chemical copper plating solution CuSO4.5 H,O・・・・・・・・・・・・・・・
・・・12gEDTA・2Na・・・・・・・・・
・・・・・・・・・・・・42g37% formalin...
・・・・・・・・・・・・3m1Mail(・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
Amount to adjust pH to 12.5 Ethoxy surfactant...
...100mg2.2゛-dipyridine...
・・・・・・-50mg deionized water・・・・・・・・・・・・
・・・・・・・・・・The characteristics of the photosensitive solder resist composition having plating resistance according to the water invention and the printed circuit board using the same are as follows in common: Judgments were made according to the following items and evaluation methods.

1) Coatability A coated film having a smooth surface without any voids or bubbles remaining in the coated film after Niscreen printing was evaluated as good.

2) Adhesive Exposure A negative mask was placed in close contact with the resist surface and exposed to UV light, and then when the negative mask was peeled off, the negative mask was rated as good if the resist did not adhere to it.

3) Developability: l, 1. ．． 1. - When the resist was spray developed with trichloroethane for 1 minute at room temperature, the unexposed areas were completely dissolved and the resist in the exposed areas did not swell, etc., and was evaluated as good.

4) Anti-bleed-through: Apply resist to a thickness of approximately 40 μm on both sides of a 1.6 mm thick glass epoxy laminate, and after drying, irradiate UV light at 0.5 J/cm from one side. Upon observation after development, those in which the resist on the back side did not harden and were completely dissolved were evaluated as good.

5) Alkali resistance: When observed after chemical copper plating, the resist surface was rated as good if it was not dissolved, discolored, or roughened.

6) Resistance to plating reactivity: Upon observation after chemical steel plating, those with no peeling or discoloration on the resist applied to the conductor circuit connected to the copper plating deposits were considered good.

7) Resistance to plating elution: When plating approximately 30 μm thick with a chemical copper plating solution that comes in contact with a resist of 1 dm per IQ, no abnormality occurs in the crystal orientation of the deposited copper. .

8) Heat resistance: Apply solder flux to the printed circuit board after chemical steel plating, immerse it in a 260°C solder bath for 10 seconds, and air cool it to room temperature. After repeating this operation 10 times, it was observed that the resist had no abnormality such as blistering or peeling, and was evaluated as good.

9) J formed on insulating glass epoxy copper clad laminate
A resist is applied on a comb-shaped pattern according to I5-C-2519, and the insulation resistance when moisture is absorbed after chemical copper plating is 1.
Those with a resistance of 0.09Ω or more were considered good.

[Example 1] A photosensitive solder resist composition having plating reactivity resistance of the present invention was prepared according to Table 1, and the properties 1) to 9) above were determined. The results are shown in Table 2.

As the polyfunctional unsaturated compound that is solid at room temperature of the present invention, diallyl phthalate resin (Daiso Tsubu A: Daiso,
Pentaerythritol tetraacrylate was used as a polyfunctional unsaturated compound that is liquid at room temperature. A mixture of benzophenone and 4,4'-bis(N,N'-dimethylamino)benzophenone was used as a photopolymerization initiator. As the epoxy resin, bisphenol A type Epicote 828 (manufactured by Yuka Shell Epoxy Co., Ltd.) was used, and 2-phenylimidazole was used as the curing agent for the epoxy resin. Compounds as shown in Table 2 were added as melamine derivatives.

Silicone oil MS-203 (manufactured by Toray Silicone, K.) was used as an antifoaming agent, and phthalocyanine green was used as a pigment. A mixture of ethyl cellosolve acetate and butyl cellosolve acetate was used as the organic solvent.

As a result of manufacturing a printed circuit board using such a resist, it was found that the melamine derivative of the present invention can be used to satisfy all the characteristics.

It has also been found that the appropriate amount to be added is 1 to 25 parts by weight per 100 parts by weight of the polyfunctional unsaturated compound that is solid at room temperature. If it is less than 1 part by weight, the adhesion between the resist and the conductor circuit will be insufficient, and the plating reactivity will not be sufficient. If it exceeds 25 parts by weight, the excess melamine derivative will slightly dissolve into the chemical copper plating solution. It was found that the crystal orientation of the deposited copper was abnormal.

As a result of X-ray diffraction, normal copper plating films have a (111) plane orientation, whereas abnormal copper plating films have a (200) orientation.
') plane was found to be preferentially oriented, and based on this, it was determined whether the copper crystal orientation was normal or abnormal.

Although such abnormalities may not be noticeable in the mechanical properties such as tensile strength or elongation of the plating film, they may cause cracks in the copper plating through-holes when soldering and mounting printed circuit boards. Therefore, from the viewpoint of through-hole reliability, this is an abnormality that should not occur.

[Example 2] A photosensitive solder resist composition having plating reactivity resistance of the present invention was prepared according to Table 3, and the properties 1) to 9) above were determined. The results are shown in Table 4.

In this example, in order to ensure the plating reactivity resistance of the resist, 3 parts by weight of 2,4-diamino-6-vinyl-s-triazine was used. I asked for As is clear from Table 4, the appropriate range of 2-phenylimidazole was 0.1 to 5 parts by weight. If the curing agent is insufficient, the alkali resistance in the chemical copper plating solution will be insufficient due to the lack of resist effect, and if the curing agent is in excess, the curing reaction will proceed when the resist dries, resulting in unused materials during development. The exposed area was not completely dissolved.

It has also been found that if the amount of curing agent is appropriate, the properties can be almost the same regardless of the type of curing agent.

[Example 3] A photosensitive solder resist composition having plating reactivity resistance of the present invention was prepared according to Table 5, and the properties 1) to 9) above were determined. The results are shown in Table 6.

In this example, the effects of a polyfunctional unsaturated compound that is solid at room temperature and a low functional unsaturated compound that is liquid at room temperature were determined.

As shown in Table 6, as polyfunctional unsaturated compounds that are solid at room temperature, Dasodatsubu A (molecular weight 10,000), Datutsu L (molecular weight 3500), and Isodatsubu (molecular weight 8
000), it was found that there was no significant difference and that both could be used for photosensitive solder resists having plating reactivity resistance.

On the other hand, as a polyfunctional unsaturated compound that is liquid at room temperature, 2.3
．． A comparison was made between the use of a 4.6-functional aliphatic unsaturated compound and a bisphenol A-based aromatic bifunctional acrylate. As shown in Table 6, the amount of unsaturated compounds added is 5 to 30.
It has been found that a resist that satisfies all the properties can be obtained by using parts by weight, preferably 10 to 30 parts by weight, more preferably 10 to 20 parts by weight. If the amount added is insufficient,
It has also been found that insufficient crosslinking during exposure causes the resist to swell during development, and if the amount added is excessive, problems occur in contact exposure.

Furthermore, it has been found that the larger the number of functional groups in the unsaturated compound, the wider the appropriate range of the amount added. From this point of view, it is desirable that the number of functional groups is 2 or more, preferably 3 or more, and it has also been found that hexafunctional aliphatic acrylate is the most excellent.

[Example 4] A photosensitive solder resist composition having plating reactivity resistance of the present invention was prepared according to Table 7, and the properties 1) to 9) above were determined. The results are shown in Table 8.

In this example, the influence of the type and amount of epoxy resin on resist properties was determined. Epicort 828 and Epicort 1001, which are bisphenol A type epoxy resins, and Epicort 1, which is a phenol borac type epoxy resin.
Resists were prepared using four types of resists: -152 and Epicote 154, and their properties were investigated.

The results are shown in Table 8, and it was found that good characteristics could be obtained no matter which epoxy resin was used. It has been found that the optimal blending amount is 5 to 40 parts by weight; if it is insufficient, the grating resistance will be insufficient, and if it is in excess, there will be problems in contact exposure.

[Example 5] A part-reactive printed circuit board was manufactured using the photosensitive solder resist composition having plating reactivity resistance of the present invention, and the limit of wiring density was determined. That is, if the line width of the circuit is 0.2.0.15. O,L.

0.05mm and through hole diameter 1.0.7.0.5
．． Printed circuit boards with different wiring densities of 0.3.0°2 mm were manufactured using the same resist as in Example 1. As a result, it was found that printed circuit boards can be manufactured with substantially the same yield using the part-reactive method, despite the above-mentioned difference in wiring density.

On the other hand, when printed circuit boards with different wiring densities were manufactured using the subtract method, the line width of the circuit was 0.1
When the through-hole diameter was 5 mm or less, the yield due to etching of the circuit decreased, and when the through-hole diameter was 0.5 mm or less, the yield due to the uniformity of electrolytic copper plating inside the through-hole decreased.

Based on these results, the present invention has a circuit line width of 0.15 m.
It has been found to be particularly advantageous for the production of high-density printed circuit boards with a srule diameter of 0.5 mm or less.

[Comparative example]

In order to compare with the photosensitive solder resist composition having plating reactivity resistance of the present invention, a resist using conventional dicyandiamide was prepared according to Table 9, and
) characteristics were determined.

As shown in Table 10, although good plating reactivity is obtained with the resist using dicyandiamide, copper plating with an abnormal crystal orientation in which the (200) plane is preferentially oriented is precipitated. It was found that it lacked plating elution resistance. Although such abnormalities may not be noticeable in the mechanical properties such as tensile strength and elongation of the plating film,
Soldering a printed circuit board causes cracks in the copper-plated through-holes when it is mounted, so it is an abnormality that should not occur from the viewpoint of through-hole reliability.

This abnormality also occurred when the amount of dicyandiamide blended was small, and it was also found that the use of dicyandiamide itself was not appropriate.

Table 1 Table 3 Table 5 Table 7 Table 9 [Effects of the Invention] As specifically explained above, the photosensitive solder resist composition having plating reactivity resistance of the present invention has excellent coating properties and adhesion. It has excellent exposure properties, developability, anti-bleed-through properties, alkali resistance, plating reactivity resistance, plating elution resistance, heat resistance, and insulation properties, and can satisfy all of these properties at the same time, making it suitable for part-additive printed circuit board manufacturing. By making it possible to apply the method to the present invention, it is possible to obtain a high-density printed circuit board suitable for practical use in a simplified manner.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the manufacturing order of a part-reactive printed circuit board according to the present invention, and FIG. 2 is a diagram showing the manufacturing order of a subtract method printed circuit board. Figure 1 Figure 1: Formation of holes in the lamina (cutting of the left corner part with a smooth electric pattern)

Claims (13)

[Claims] 1. It contains a polyfunctional unsaturated compound that is solid at room temperature, a polyfunctional unsaturated compound that is liquid at room temperature, a photopolymerization initiator, an epoxy resin, a curing agent for the epoxy resin, and a melamine derivative. Characteristic photocurable resist composition. 2. In claim 1. The polyfunctional unsaturated compound that is solid at room temperature is a prepolymer of diallyl phthalate,
A photocurable resist composition characterized in that the polyfunctional unsaturated compound that is liquid at room temperature is a polyfunctional acrylate or methacrylate compound. 3. Claim 2, characterized in that the prepolymer of diallyl phthalate has a molecular weight of 3,000 to 30,000, and the polyfunctional unsaturated compound that is liquid at room temperature is a polyfunctional acrylate or methacrylate compound with a functional group number of 3 or more. A photocurable resist composition. 4. A photocurable melamine derivative according to claim 1, wherein one or more amino groups of melamine and/or H of the amino group is substituted with a substituent having a photopolymerizable unsaturated bond. sex resist composition. 5. The photocurable resist composition according to claim 1, wherein the curing agent for the epoxy resin is an imidazole derivative. 6. 2. The photocurable resist composition according to claim 1, wherein the melamine derivative and the curing agent for the epoxy resin have a common compound. 7. The melamine derivative according to claim 1 is 2,4
-Diamino-6-vinyl-s-triazine, 2,4-diamino-6-(2-methacryloylethyl)-s-triazine, N(2),N(2)-diallylmelamine A photocurable resist composition characterized by: 8. 2. The photocurable resist composition according to claim 1, wherein the melamine derivative is contained in an amount of 1 to 25 parts by weight based on 100 parts by weight of the diallyl phthalate prepolymer. 9. For 100 parts by weight of diallyl phthalate prepolymer, the amount of polyfunctional acrylate or methacrylate compound that is liquid at room temperature is 5 to 30 parts by weight, the amount of photopolymerization initiator is 2 to 12 parts by weight, and the epoxy resin is mixed. The amount is 5 to 40 parts by weight, and the amount of the epoxy resin curing agent is 0.1 to 5 parts by weight. A photocurable resist composition characterized in that the amount of a melamine derivative contained is 1 to 25 parts by weight. 10. The photocurable resist composition according to claim 8 contains 0.5 to 10 parts by weight of an antifoaming agent and 50 to 10 parts by weight of a solvent.
0 parts by weight, and 0.2 to 10 parts by weight of a pigment. 11. A printed circuit board characterized by using the photocurable resist composition according to any one of claims 1 to 10. 12. 12. The printed circuit board according to claim 11, wherein a photocurable resist is formed on a copper foil circuit, and then through-hole connections are made by chemical copper plating. 13. The printed circuit board according to claim 11 or 12, wherein the printed circuit board has a copper foil circuit width of 0.15 mm or less and a through hole diameter of 0.5 mm or less.