JPH08335768A - Alkaline developable one liquid photosolder resist composition and solder resist film obtainable from the resist - Google Patents

Abstract

PURPOSE: To provide an excellent hardened film through simple irradiation with active energy beam after exposure and development by containing a solid state polymer compound or oligomer having a carboxyl group or carboxyl group and a photoreactive unsaturated group, a liquid state multifunctional unsaturated group and/or an organic solvent, a photopolymerization starting agent, and a specified melamine based compound. CONSTITUTION: The alkaline developable one liquid photosolder resist composition contains a polymer compound, taking solid state under room temperature, having one or more free carboxyl group or one or more free carboxyl group and one or more photoreactive unsaturated group in one molecule, a multifunctional unsaturated group and/or an organic solvent as a diluent taking liquid state under room temperature, a photopolymerization starting agent, and a melamine based compound as shown by the formula or its derivatve. In the formula, R represents -NH2 , -OCH3 , an aromatic hydrocarbon or an alkyl group of 1-4C. Furthermore, the composition may contain 2,4,6-trimercapto- S-triazine.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an alkali-developable one-pack type solder resist composition, and more specifically,
It is suitable for use as a permanent mask for printed wiring boards. After exposure, it is developed with an alkaline aqueous solution to form an image, and by irradiation with active energy rays and / or heat treatment for final curing, heat resistance, adhesion and resistance The present invention relates to an alkali-developable one-liquid type solder resist composition capable of forming a cured film having excellent electrolytic plating properties and electrical characteristics. The present invention also relates to a solder resist film obtained from the above composition.

[0002]

2. Description of the Related Art Currently, solder resists for some consumer printed wiring boards and most industrial printed wiring boards are exposed to light and developed to form an image by heat treatment from the viewpoint of high accuracy and high density. Further, a liquid development type solder resist which is finish cured (mainly cured) by light irradiation is used. Further, in consideration of environmental problems, an alkali developing type liquid solder resist using a dilute alkaline aqueous solution as a developing solution has become the mainstream. As an alkaline developing type solder resist using such a dilute aqueous alkaline solution, for example, in JP-A-61-243869, an acid anhydride is added to a reaction product of a novolac type epoxy compound and an unsaturated monobasic acid. A solder resist composition comprising a photosensitive resin, a photopolymerization initiator, a diluent, and an epoxy compound is disclosed in JP-A-3-253093, in which a reaction product of a novolac type epoxy compound and an unsaturated monobasic acid is acidified. A solder resist composition comprising a photosensitive resin to which an anhydride is added, a photopolymerization initiator, a diluent, vinyltriazine or a mixture of vinyltriazine and dicyandiamide, and a melamine resin, and JP-A-4-281454 discloses a novolak. Diolefin and maleic anhydride as the reaction product of unsaturated epoxy compound and unsaturated monobasic acid A one-pack type solder resist composition consisting of a photosensitive resin to which an alicyclic dibasic acid anhydride is obtained by the reaction of, a photopolymerization initiator, a diluent, and a vinyltriazine-based compound as a thermosetting accelerator. It is disclosed.

[0003]

However, most of the liquid alkaline development type solder resists currently on the market are photosensitive materials obtained by adding an acid anhydride to the reaction product of a novolac type epoxy compound and an unsaturated monobasic acid. It is a two-component solder resist consisting of a main agent mainly composed of resin, photopolymerization initiator, etc., and a curing agent mainly composed of a diluent or an epoxy compound. It is used after thoroughly mixing the main agent and the curing agent. If not done, sufficient characteristics cannot be obtained. In addition, the pot life after mixing is as short as several hours to one day, and even during the drying process and the developing process, the carboxyl groups contained in the photosensitive resin as the main component and the epoxy groups of the epoxy compound in the curing agent gradually increase. There are many problems in work such as poor development due to reaction. Also, the solder resist using a melamine resin has a longer pot life than the epoxy type, but it is a two-component type, and it easily absorbs moisture in the atmosphere between the drying step and the exposure step, and thus has a good finger performance. Workability problems, such as the lack of dryness to the touch, and the uncured melamine resin, which has a high hydrophilicity, allows the developer to penetrate into the exposed areas during the development process, resulting in ionic impurities in the final cured film. There is concern that it may remain.

On the other hand, as a one-pack type photo solder resist, an alicyclic dibasic acid anhydride is added to a reaction product of a novolac type epoxy compound and an unsaturated monobasic acid as disclosed in the above-mentioned JP-A-4-281454. A composition comprising a photosensitive resin, a photopolymerization initiator, a diluent, and a vinyltriazine-based compound is disclosed, but the vinyltriazine-based compound is used as a thermal curing accelerator, and the characteristics of a perfect solder resist are obtained. To meet the requirement, 150 after exposure and development
It is premised that heat curing at a high temperature of ℃ is required. Therefore, it is not possible to cope with the thinning and surface mounting of the printed wiring board which has been rapidly spreading recently. That is, when the thin film base material is subjected to a heat treatment at a high temperature of 150 ° C., the base material warps, and surface mounting of components becomes impossible.

Therefore, the object of the present invention is not to have the above-mentioned drawbacks, to be excellent in storage stability as one solution and workability in the solder resist forming step, and to be satisfactory as a solder resist in heat resistance, adhesion and resistance. A one-pack type liquid solder resist composition capable of obtaining a cured film having various properties such as electroless plating properties and electrical properties, capable of supporting thinning of printed wiring boards and surface mounting, and alkali-developable liquid solder resist composition and obtained therefrom It is to provide a solder resist film. Another object of the present invention is to obtain a cured film excellent in the above-mentioned various properties only by irradiation with active energy rays or heat treatment after exposure or development, or by both treatments, and therefore, the work flexibility is extremely good. It is to manufacture a solder resist film with good mass productivity and workability. Further, the object of the present invention is to obtain a cured film excellent in the above-mentioned various properties only by irradiation with active energy rays after exposure and development, and the conventional high temperature heating step is not required. Mass production, surface mounting,
It is to manufacture a solder resist film with good workability.

[0006]

In order to achieve the above object, according to one aspect of the present invention, there is provided an alkali developable one-pack type solder resist composition, the first aspect of which is (A) ) A polymer compound or oligomer having at least one or more free carboxyl groups in one molecule, or further having one or more photoreactive unsaturated groups, which is solid at room temperature, (B) as a diluent A polyfunctional unsaturated compound and / or an organic solvent which is liquid at room temperature, (C) a photopolymerization initiator, and (D) a melamine represented by the following general formula (1) or a derivative thereof. .

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On the other hand, in the second embodiment, (A) at least one free carboxyl group in one molecule, or at least one photoreactive unsaturated group, is solid at room temperature. Polymer compound or oligomer, (B) room temperature liquid polyfunctional unsaturated compound and / or organic solvent as diluent, (C) photopolymerization initiator, (D) melamine represented by the general formula (1), or Its derivatives, and (E)
It is characterized by containing 2,4,6-trimercapto-S-triazine.

According to another aspect of the present invention, the alkali-developable one-pack type solder resist composition is screen-printed, roll-coated, or curtain-coated on a substrate, for example, a circuit-formed printed wiring board surface. , Spray coating, etc., dry in a far-infrared ray drying oven, hot air drying oven, etc., and then directly irradiate with an active energy ray such as a laser beam in a pattern, or through a pattern-formed photomask, a high-pressure mercury lamp. , An ultra-high pressure mercury lamp, a metal halide lamp, an electrodeless lamp, etc., to irradiate actinic rays to selectively expose the exposed pattern according to a predetermined exposure pattern, and develop the unexposed part with an alkaline aqueous solution to form a resist pattern. Irradiation with active energy rays (active rays) or 100 to 150
By heat-treating at 0 ° C. or by finishing curing by both of these treatments, a solder resist film excellent in various properties such as heat resistance, adhesion, electroless plating resistance, and electrical properties is provided.

[0009]

The present inventor has diligently studied a method for improving the above-mentioned problems, and as a result, has at least one or more free carboxyl groups in one molecule, or further one or more photoreactions. At room temperature, which is solid at room temperature and which has a polyunsaturated group, or an oligomer (A) is converted into melamine represented by the general formula (1) or its derivative (D).
Alternatively, by further using it in combination with 2,4,6-trimercapto-S-triazine (E), it has excellent storage stability as one liquid, good workability, mass productivity and heat resistance,
A one-pack type alkali-developable type that can form a resist film with excellent properties such as adhesion, electroless plating resistance, electrical insulation, and electrolytic corrosion, and that can be completely cured by irradiation with active energy rays and / or heat treatment. The inventors have found that a solder resist composition can be obtained, and completed the present invention.

That is, the liquid solder resist composition of the present invention comprises, first of all, a film-forming component without using a heat-reactive epoxy resin or melamine resin which has been conventionally used in order to achieve one-liquefaction. It is characterized in that only the unsaturated group is used as the reactive group. This unsaturated group, for example, an unsaturated double bond, easily undergoes a reaction by light irradiation in the presence of a photopolymerization initiator, but a temperature of 170 ° C. or higher is required for the reaction to occur due to heat. Therefore, the composition containing such a film-forming component exhibits excellent storage stability, and one-liquefaction, which is one of the objects of the present invention, is achieved.

However, the cured film formed by the photopolymerization reaction of only unsaturated groups becomes hard and brittle, and the characteristics such as sufficient adhesion and solder heat resistance as a solder resist cannot be obtained. It is considered that this is because the curing shrinkage caused by the reaction of the unsaturated group is larger than that of the epoxy system, and the problems were overcome by the following measures and research results, and the present invention was completed.

That is, the second feature of the liquid solder resist composition of the present invention is that melamine or a derivative thereof is used to improve the adhesion of the coating film. Melamine or a derivative thereof used at this time is a non-reactive basic compound such as melamine, acetoguanamine, and benzoguanamine, and the polar molecule contained in the coating film and the chelating effect on the copper foil on the printed wiring board from its basicity. With the hydrogen bonding effect of, the adhesion between the coating film and the copper foil can be enhanced. That is, the two amino groups of the melamine or its derivative form a chelate with the copper foil (Cu) of the printed wiring board, and the remaining amino groups or functional groups are polar groups (for example, carboxyl groups) of the coating film forming component. It is considered that hydrogen bonds are formed, and thus, the melamine or the derivative thereof couples the copper foil and the coating film forming component to improve the adhesion between them.

The liquid solder resist composition of the second aspect of the present invention is characterized in that, in addition to the non-reactive basic compound melamine or its derivative (D), it is a reactive acidic compound 2,4. It was found that 6-trimercapto-S-triazine (E) was added, which revealed that the coating film characteristics such as solder heat resistance were improved. This is because the --SH group of this compound reacts with the unsaturated double bond of the film-forming resin, and the acidic 2,4,6-trimercapto-S-triazine reacts with the basic melamine or its derivative. It is considered that since it forms a strong salt structure, it has a function of making the chelating effect of the non-reactive melamine or its derivative stronger. At this time, when 2,4,6-trimercapto-S-triazine is used alone or added in a large amount exceeding twice the equivalent amount of melamine or its derivative, the -SH group and unsaturated group of the compound are added. Since the addition reaction with and proceeds even at room temperature and the composition thickens,
It cannot be used as a one-part composition. However, when 2,4,6-trimercapto-S-triazine is added in an amount of 2 times equivalent or less, preferably 1.5 times equivalent or less with respect to the addition amount of melamine or a derivative thereof,
It does not thicken or gel because it forms a stable salt with melamine or its derivatives in the composition.

Further, in a preferred embodiment of the liquid solder resist composition of the present invention, in order to reduce the curing shrinkage as described above, it is preferable to use an inorganic filler and to use a relatively large amount. An appropriate amount of the inorganic filler is 100% of the solid content of the polymer compound or oligomer (A).
The amount is 50 to 500 parts by weight, more preferably 150 to 350 parts by weight, based on parts by weight. If the compounding amount of the inorganic filler is less than 50 parts by weight, the curing shrinkage suppressing effect is not sufficient, and the adhesiveness and solder heat resistance of the formed solder resist are lowered, while the compounding amount exceeds 500 parts by weight. In that case, the composition is unlikely to be in a paste form, and the chemical resistance of the coating film is lowered, or undeveloped residue occurs, which is not preferable.

In still another preferred embodiment of the one-pack type alkali-developable solder resist composition of the present invention,
The present invention is characterized in that a polyfunctional unsaturated group-containing compound which is solid or semi-solid at room temperature is used for the purpose of providing contrast between the curing degree during image formation and the curing degree during finish curing.
As a result, good results are obtained in both the photo-curing property and the cured film property.

The constituents of the one-pack type solder resist composition of the present invention will be described in detail below. First, the polymer compound (A) used in the present invention, which is solid at room temperature, has at least one or more free carboxyl groups in one molecule, or further has one or more photoreactive unsaturated groups. Or, as an example of the oligomer, the following (a) to
Resins such as (d) may be mentioned, which may be used alone or in 2
A combination of two or more species can be used. It is preferable that all of these resins have an acid value of 30 to 200 mgKOH / g. When the acid value is less than 30 mgKOH / g, the solubility in an alkaline aqueous solution becomes poor and the development becomes difficult. Conversely, the acid value is 200mgKOH
If the amount is more than / g, the surface of the coating film in the exposed area is developed regardless of the exposure conditions, which is not preferable.

(A) Carboxyl group-containing compound obtained by the addition reaction of a hydroxyl group formed in the esterification reaction of a cresol novolac type epoxy compound or a phenol novolac type epoxy compound with an unsaturated monobasic acid with a dibasic acid anhydride It is a photosensitive resin. The molar ratio of the epoxy group to the unsaturated monobasic acid during the esterification reaction is preferably 1: 1 and the molar ratio of the hydroxyl group and the dibasic acid anhydride produced in this case is 0.2 to 1 mol of the hydroxyl group. 0.7 mol is preferred. The resin thus obtained is heat-resistant due to the benzene skeleton of the cresol novolac type epoxy compound or the phenol novolac type epoxy compound, the reactivity of the unsaturated group, and the free radical generated in the reaction of the hydroxyl group and the dibasic acid anhydride. It is a well-balanced resin in which the alkali developability is imparted by the carboxyl group.

(B) A compound having one epoxy group and one unsaturated group in one molecule and one or more kinds of compounds having one unsaturated group in one molecule are radically or anionically polymerized to have a molecular weight of 3,000 to 60,000. In the same manner as in the above (a), the epoxy group of the copolymer of (1) is reacted with an unsaturated monobasic acid, and the secondary hydroxyl group generated at that time is adjusted to a dibasic acid value of 30 to 200 mgKOH / g. It is a carboxyl group-containing photosensitive resin formed by adding an acid anhydride, and it has a film-forming property due to the effect of molecular weight, the reactivity of unsaturated groups, and the free carboxyl group generated during the reaction of a hydroxyl group with a dibasic acid anhydride. The resin has developability. If the molecular weight is less than 3,000, the solder heat resistance will be low, while if it is more than 60,000, the developability of the composition will be poor, which is not preferable, and the same applies to the following resins.

(C) An unsaturated monobasic acid and one or more kinds of compounds having one unsaturated group in one molecule are radically or anionically polymerized into a copolymer having a molecular weight of 3,000 to 60,000 and one in one molecule. The acid value of the final product is 3 when the epoxy group of a compound having both an epoxy group and one unsaturated group is used.
It is a carboxyl group-containing photosensitive resin that is added to the free carboxyl group of the above copolymer so as to be 0 to 200 mgKOH / g, and has film-forming properties due to the effect of molecular weight, reactivity of unsaturated groups, and free carboxyl groups. The resin has developability.

(D) A carboxyl group-containing resin composed of a copolymer having a molecular weight of 3000 to 60,000 obtained by radical or anion polymerization of an unsaturated monobasic acid and one or more kinds of compounds having one unsaturated group in one molecule. . In particular, although this resin does not have a photoreactive group, it has a higher softening point than other resins, is excellent in dryness to the touch, and has good developability. Therefore, the molecular weight should be set higher than that of other resins. And a resin having film-forming property and heat resistance due to the effect of molecular weight. Also, even if it does not contain a photoreactive unsaturated group,
By the presence of a liquid polyfunctional unsaturated compound at room temperature to be added as a diluent, or preferably by separately adding a solid or semi-solid polyfunctional unsaturated group-containing compound at room temperature as described later, It has sufficient photocurability.

The above-mentioned photosensitive resin containing a carboxyl group (a to
Typical examples of the unsaturated monobasic acid used for the preparation of c) or the carboxyl group-containing resin (d) include acrylic acid, methacrylic acid, or hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, Unsaturated dibasic acid anhydrides of hydroxy group-containing acrylates such as hydroxybutyl (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, and phenylglycidyl (meth) acrylate. Examples of dibasic acid anhydrides include phthalic anhydride, methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, succinic anhydride, and maleic anhydride. Acid, itaconic acid anhydride, and the like nadic acid.

Examples of the compound having one epoxy group and one unsaturated group in one molecule include glycidyl (meth) acrylate and N- [4- (2,3-epoxypropoxy) -3,5-dimethylbenzyl]. Acrylamide (Kanekarezine AXE, manufactured by Kanegafuchi Chemical Industry Co., Ltd.), aryl glycidyl ether, (meth) acrylic monomer having an alicyclic epoxy group, for example, CY manufactured by Daicel Chemical Industries, Ltd.
CLOMER M-100, A-200, etc. are mentioned.

As the compound having one unsaturated group in one molecule, vinyl compounds such as styrene, substituted styrene and vinyl acetate; methyl (meth) acrylate, ethyl (meth) acrylate, lauryl (meth) acrylate, Alkyl (meth) acrylates such as isopropyl (meth) acrylate and t-butyl (meth) acrylate; 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, phenyl ( Acrylic esters such as (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, phenylglycidyl ether (meth) acrylate N- phenylmaleimide, etc. N- cyclohexyl maleimide.

As the diluent (B), a polyfunctional unsaturated compound which is liquid at room temperature or an organic solvent can be used. The purpose of using these diluents is to dissolve the polymer compound or oligomer (A) and adjust the composition to have a viscosity suitable for various coating methods. Further, since the polyfunctional unsaturated compound which is liquid at room temperature has a function of enhancing the photoreactivity of the composition and a function of assisting the solubility in an alkaline aqueous solution, 100 parts by weight of the polymer compound or oligomer (A) ( It is preferable to add 5 parts by weight or more based on the solid content.
However, if a large amount of a polyfunctional unsaturated compound that is liquid at room temperature is used, it is difficult to obtain the dryness to the touch of the coating film after drying, so it may be necessary to adopt a non-contact exposure method in some cases. Since the characteristics of (1) also tend to be deteriorated, 100 parts by weight or less, particularly 50 parts by weight or less is preferable with respect to 100 parts by weight (solid content) of the polymer compound or oligomer (A). Regarding the organic solvent, if it can be dried under predetermined drying conditions, it does not adversely affect the dried coating film, and the amount used is limited only by the coating method,
Generally, the range of 5 to 300 parts by weight is suitable.

Examples of polyfunctional unsaturated compounds which are liquid at room temperature include hydroxyl group-containing acrylates such as 2-hydroxyethyl acrylate, 2-hydroxy acrylate, pentaerythritol triacrylate and dipentaerythritol pentaacrylate; acrylamide and N-methylol acrylamide. Acrylamide derivatives such as;
Water-soluble acrylates such as polyethylene glycol diacrylate and polypropylene glycol diacrylate; polyfunctional acrylates such as trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate; and methacrylates corresponding to the above acrylates. And the like, and can be used alone or in combination of two or more kinds.

Examples of the organic solvent include ketones, cellosolves, carbitols, cellosolve acetates, carbitol acetates, propylene glycol ethers, dipropylene glycol ethers, propylene glycol ether acetates, dipropylene glycol ether acetates. , Aromatic hydrocarbons, etc.,
They can be used alone or as a mixture of two or more kinds.

As the photopolymerization initiator (C), benzoin and benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2, Acetophenones such as 2-diethoxy-2-phenylacetophenone and 1,1-dichloroacetophenone; 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinoaminopropanone-1,2-benzyl-2- Aminoacetophenones such as dimethylamino-1- (4-morpholinophenyl) -butanone-1, N, N-dimethylaminoacetophenone; 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiarybutylanthra. Non, such anthraquinones 1-chloro anthraquinone; 2,4-dimethyl thioxanthone, 2,4-diethyl thioxanthone, 2-
Thioxanthones such as chlorothioxanthone and 2,4-diisopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyldimethyl ketal; benzophenones and xanthones such as benzophenone and 4,4′-bisdiethylaminobenzophenone; 2,4,6- Trimethylbenzoyldiphenylphosphine oxide and the like can be used. These known and commonly used photopolymerization initiators can be used alone or as a mixture of two or more kinds, and further, tertiary ethanol such as triethanolamine can be used.
Photoinitiating aids such as amines, ethyl dimethylaminobenzoate and the like can be added. The amount of its use is preferably 0.5 to 20 parts by weight with respect to 100 parts by weight (solid content) of the polymer compound or oligomer (A).

The melamine represented by the general formula (1) or its derivative (D) can be used alone or as a mixture of two or more kinds. Specific examples include melamine, acetoguanamine, benzoguanamine and the like. The purpose of using these is to improve the adhesion to copper, and as a result, the heat resistance and electroless plating resistance of the cured film are improved. The blending amount is 0.1 to 100 parts by weight (solid content) of the polymer compound or oligomer (A).
10 parts by weight is preferable, and if it is less than 0.1 parts by weight, the adhesiveness-imparting effect is hardly obtained. On the contrary, if it is more than 10 parts by weight, the stability as one liquid and the resistance of the cured film are deteriorated, which is not preferable. .

Known inorganic fillers include barium sulfate, barium titanate, silicon oxide powder, finely powdered silicon oxide, amorphous silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide and mica. Conventional inorganic fillers may be used alone or in combination of two or more. These are used for the purpose of suppressing curing shrinkage of the coating film and improving properties such as adhesion and hardness. The compounding amount of the inorganic filler is as described above.

The composition of the present invention contains a polyfunctional unsaturated group-containing compound which is solid or semi-solid at room temperature, such as bisphenol A type epoxy, for the purpose of improving photocurability, heat resistance and chemical resistance. A compound, a bisphenol F type epoxy compound, a cresol novolac type epoxy compound or a reaction product of a phenol novolak type epoxy compound with an unsaturated monobasic acid, or a compound having one epoxy group and one unsaturated group in one molecule 1 or more of 1
Epoxy (meth) acrylate, such as a reaction product of a copolymer having a molecular weight of several thousand to tens of thousands consisting of a compound having one unsaturated group in the molecule and an unsaturated monobasic acid, or a known and commonly used unsaturated polyester resin Can be added alone or in combination of two or more. Here, as the compound having an unsaturated monobasic acid or one epoxy group and one unsaturated group in one molecule, the compound described above can be used as the compound having one unsaturated group in one molecule.

The composition of the present invention may further, if desired,
Phthalocyanine green, phthalocyanine blue, disazo yellow, crystal violet, titanium oxide,
Known conventional colorants such as carbon black, Orben,
Benton, known and conventional thixotropic agents such as montmorillonite,
Known defoaming agents such as silicone type, fluorine type or polymer type, leveling agents and the like can be added.

The solder resist ink composition of the present invention having the above composition is diluted as needed to adjust the viscosity to a value suitable for the coating method, and the viscosity is adjusted to a screen on a circuit-formed printed wiring board, for example. A tack-free coating film is obtained by applying by a printing method, a curtain coating method, a spray coating method, a roll coating method, or the like, and evaporating and drying the organic solvent contained in the composition at a temperature of 60 to 100 ° C., for example. Can be formed. Then, a laser beam or the like is directly irradiated according to the exposure pattern, or it is selectively exposed with an active energy ray through a photomask on which a predetermined exposure pattern is formed, and the unexposed portion is developed with a dilute alkaline aqueous solution to form a resist pattern. Can be formed, and further by final curing by irradiation with active energy rays or heat treatment at 100 to 150 ° C., or both,
A solder resist film having excellent adhesion, hardness, solder heat resistance, chemical resistance, solvent resistance, electrical insulation, electrolytic corrosion resistance, and plating resistance is formed.

As the alkaline aqueous solution, an alkaline aqueous solution of potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines or the like can be used. A low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp or a metal halide lamp is suitable as an irradiation light source for photocuring. In addition, a laser beam or the like can also be used as an actinic ray.

[0034]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but it goes without saying that the present invention is not limited to the following Examples. The terms "part" and "%" are based on weight unless otherwise specified.

Synthesis Example 1 Cresol novolac type epoxy resin Epicron N-
695 (manufactured by Dainippon Ink and Chemicals, Inc., epoxy equivalent = 2
20) 220 parts was put into a four-necked flask equipped with a stirrer and a reflux condenser, and 214 parts of carbitol acetate was added and dissolved by heating. Next, 0.1 part of hydroquinone as a polymerization inhibitor and 2.0 parts of dimethylbenzylamine as a reaction catalyst were added. This mixture was heated to 95 to 105 ° C., 72 parts of acrylic acid was gradually added dropwise, and the mixture was reacted for 16 hours. The reaction product is cooled to 80-90 ° C,
106 parts of tetrahydrophthalic anhydride was added and reacted for 8 hours, cooled, and taken out. The photosensitive resin having both ethylenically unsaturated bond and carboxyl group thus obtained has a nonvolatile content of 65% and a solid acid value of 100 mg.
It was KOH / g and Mw 3,500. Hereinafter, this reaction solution is referred to as a varnish.

Synthesis Example 2 A flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser was charged so that the molar ratio of methyl methacrylate and glycidyl methacrylate was 4: 6, and the solvent was carbitol acetate and a catalyst. Azobisisobutyronitrile (hereinafter, abbreviated as AIBN) was used as the resin and stirred at 80 ° C. for 4 hours in a nitrogen atmosphere to obtain a resin solution. This resin solution was cooled, and methylhydroquinone was used as a polymerization inhibitor, tetrabutylphosphonium bromide was used as a catalyst, and acrylic acid was added to 100% of the epoxy groups at 95 to 105 ° C. for 16 hours. The reaction product was cooled to 80 to 90 ° C., tetrahydrophthalic anhydride was reacted for 8 hours, and after cooling, taken out. The thus obtained photosensitive resin having both an ethylenically unsaturated bond and a carboxyl group had a nonvolatile content of 65%, a solid acid value of 100 mgKOH / g and an Mw of 15,000. Hereinafter, this reaction solution is referred to as b varnish.

Synthesis Example 3 A flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser was charged with methyl methacrylate, ethyl methacrylate, and methacrylic acid in a molar ratio of 1: 1: 2. Dipropylene glycol monomethyl ether was added as a solvent, and AIBN was added as a catalyst, and the mixture was stirred under a nitrogen atmosphere at 80 ° C. for 4 hours to obtain a resin solution. This resin solution is cooled, methyl hydroquinone is used as a polymerization inhibitor, tetrabutylphosphonium bromide is used as a catalyst, and glycidyl methacrylate is added at 95 to 105 ° C. for 1 hour.
20 mol% addition reaction was carried out under the condition of 6 hours, and after cooling, it was taken out. The photosensitive resin having both an ethylenically unsaturated bond and a carboxyl group thus obtained has a nonvolatile content of 65%, a solid acid value of 120 mgKOH / g, and Mw3.
It was 5,000. Hereinafter, this reaction solution is referred to as a c varnish.

Synthesis Example 4 In a flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser, methyl methacrylate, ethyl methacrylate, phenylglycidyl methacrylate, and methacrylic acid were added in a molar ratio of 2: 2: 3: 3. Charged by the ratio, dipropylene glycol monomethyl ether as the solvent, AI as the catalyst
Using BN, the resin solution was obtained by stirring at 80 ° C. for 4 hours in a nitrogen atmosphere. The photosensitive resin having a carboxyl group thus obtained has a nonvolatile content of 65% and a solid acid value of 1
It was 20 mgKOH / g and Mw25,000. Hereinafter, this reaction solution is referred to as d varnish. In the above synthesis example, the molecular weight was measured by using a pump LC-6AD manufactured by Shimadzu Corporation and a column Shodex manufactured by Showa Denko KK
(Registered trademark) KF-804, KF-803, KF-80
The measurement was carried out by high performance liquid chromatography in which 3 of 2 were connected.

Examples 1 to 12 and Comparative Examples 1 to 8 Using the varnishes obtained in each of the above synthesis examples, the compounding ingredients shown in Tables 1 to 3 were kneaded with a three-roll mill to obtain photosensitive resin compositions. It was The characteristic values of each composition are also shown in Tables 1 to 3. The method of the performance test in each table is as follows.

(1) One-liquid stability: The compositions of the above Examples and Comparative Examples were stored in a thermo-hygrostat at 20 ° C., and the EHD viscometer was measured for 5 rotations from 1 to 60 days. The presence or absence of thickening was confirmed. The judgment criteria are as follows. ◯: The viscosity increase rate is within 120%. Δ: Thickening rate is within 200%. X: Gelation or viscosity increase of 200% or more.

Characteristic test: The compositions of the above Examples and Comparative Examples were screen-printed on a patterned copper foil substrate and dried at 90 ° C. for 10 minutes to form a tack-free coating film. . A negative film is applied to this substrate, exposed according to the solder resist pattern, and the spray pressure is 2 kg.
/ Cm ² of 1% sodium carbonate aqueous solution was developed to form a pattern. This substrate has a cumulative exposure of 1 in a UV conveyor furnace.
Ultraviolet irradiation at 000 mJ / cm ² was applied to finish and cure, and an evaluation substrate was produced.

(2) Solder heat resistance: The evaluation substrate coated with the rosin flux was immersed in a solder bath set at 260 ° C. for 5 seconds, the flux was washed with denatured alcohol, and then the resist layer swelled by visual observation. The peeling was evaluated. The judgment criteria are as follows. ⊚: No peeling is observed even after repeating immersion for 5 seconds 6 times or more. Good: No peeling is observed even after repeating the immersion for 5 seconds three times or more. (Triangle | delta): It peels a little when a 5 second immersion is repeated 3 times or more. X: The coating film swells and peels off after one immersion.

(3) Adhesion: The evaluation board was JIS
According to the test method of D-0202, cross-cuts were put in a grid pattern, and a peel test with a cellophane adhesive tape was performed to evaluate peeling of the resist layer. The judgment criteria are as follows. ◯: No peeling was observed at all Δ: Slightly peeled off ×: Peeled coating film

(4) Resistance to electroless gold plating: Using a commercially available electroless nickel plating bath and electroless gold plating bath, plating was performed under the conditions of nickel 5 μm and gold 0.03 μm, and tape peeling was performed to remove the resist layer. The presence or absence of peeling and the presence or absence of plating penetration were evaluated. The judgment criteria are as follows. ◯: No change was observed at all Δ: Slightly peeled off or soaked ×: Stripped film

(5) Electrolytic property: IPC instead of the copper foil substrate
Using the comb-shaped electrode B coupon of B-25, an evaluation substrate was prepared under the above conditions, a bias voltage of DC 100 V was applied to the comb-shaped electrode, and 40 ° C., 90% R.S. H. The presence or absence of migration after 500 hours was confirmed in the constant temperature and humidity chamber. The judgment criteria are as follows. ◯: No change observed Δ: Slightly changed ×: Migration occurred

(6) Electric insulation: IP instead of the copper foil substrate
Using the comb-shaped electrode B coupon of CB-25, an evaluation substrate was prepared under the above conditions, and DC500V was applied to this comb-shaped electrode.
Was applied and the insulation resistance value was measured.

[0047]

[Table 1] As is clear from the results shown in Table 1, Example 1 of the present invention
The liquid solder resist compositions of to 4 were excellent in one-liquid stability, and the cured film obtained was also excellent in solder heat resistance, adhesion, resistance to electroless gold plating, electrolytic corrosion resistance, and electrical insulation. In Comparative Examples 1 to 4 using the liquid solder resist compositions containing no melamine, the cured film was inferior in solder heat resistance and electroless gold plating resistance, and the adhesion was not so good.

[0048]

[Table 2] As is clear from the results shown in Table 2, Example 5 of the present invention
The liquid solder resist compositions of to 8 were excellent in one-liquid stability, and the obtained cured film was also excellent in solder heat resistance, adhesion, resistance to electroless gold plating, electrolytic corrosion resistance, and electrical insulation. Comparative Example 6 using a liquid solder resist composition containing 2,4,6-trimercapto-S-triazine alone and 2.5 times the amount of 2,4,6-trimercapto-S-triazine of melamine. In Comparative Example 5 using the contained liquid solder resist composition, the stability of one liquid is poor, and it is necessary to form a two liquid type when carrying out. On the other hand, instead of melamine, dicyandiamide or 2-
In Comparative Examples 7 and 8 using the liquid solder resist composition containing methylimidazole, the one-liquid stability was good, but the cured film was inferior in solder heat resistance and electroless gold plating resistance.

[0049]

[Table 3] As is clear from the results shown in Table 3, when a liquid solder resist composition containing a sufficient amount of an inorganic filler was used (Examples 10 to 12), one-liquid stability was excellent and the cured film obtained was Although it was excellent in solder heat resistance, adhesion, electroless gold plating resistance, electrolytic corrosion resistance, and electrical insulation, when a liquid solder resist composition containing no inorganic filler was used (Example 9), the cured film was Solder heat resistance and electroless gold plating resistance were slightly inferior to those of Examples 10-12.

[0050]

As described above, the liquid photosolder resist composition of the present invention has at least one or more free carboxyl groups in one molecule, or one or more photoreactive unsaturated groups. The polymer compound or oligomer (A) which is solid at room temperature and has melamine represented by the general formula (1) or a derivative thereof (D) or 2,4,6-trimercapto-S-triazine (E). Since it is used in combination with alkaline development, it is excellent in storage stability as one solution, and the formed coating film can be completely cured by exposure to active energy rays and / or heat treatment after exposure and development. Workability is very good, and a solder resist film with excellent workability such as heat resistance, adhesion, electroless plating resistance, electrical insulation, and electrolytic corrosion is provided. Produced good can be formed. Further, according to one embodiment of the present invention, a cured film excellent in various characteristics as described above can be obtained only by irradiation with active energy rays after exposure and development, and a conventional high temperature heating step is unnecessary, and therefore, a print It can be applied to thin wiring and surface mounting of wiring boards, and can produce printed wiring boards with good mass productivity and workability.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03F 7/038 G03F 7/038

Claims (11)

[Claims] 1. A polymer compound or oligomer which is solid at room temperature and has (A) at least one or more free carboxyl groups in one molecule, or one or more photoreactive unsaturated groups. (B) Polyfunctional unsaturated compound and / or organic solvent which is liquid at room temperature as a diluent, (C) a photopolymerization initiator, and (D) a melamine represented by the following general formula (1) or a derivative thereof. An alkali-developable one-pack type solder resist composition comprising: Embedded image 2. (A) A polymer compound or oligomer which is solid at room temperature and has at least one or more free carboxyl groups in one molecule, or further has one or more photoreactive unsaturated groups, (B) Room temperature liquid polyfunctional unsaturated compound and / or organic solvent as diluent, (C) photopolymerization initiator, (D) melamine represented by the following general formula (1) or a derivative thereof, And (E) 2,4,6-trimercapto-S-triazine, an alkali-developable one-pack type solder resist composition. Embedded image 3. A carboxyl group-containing product obtained by adding an acid anhydride to a reaction product of a cresol novolac type epoxy compound or a phenol novolac type epoxy compound and an unsaturated monobasic acid, the polymer compound or oligomer (A). The one-component solder resist composition according to claim 1, which is a photosensitive resin. 4. A compound in which the polymer compound or oligomer (A) has one epoxy group and one unsaturated group in one molecule, and one or more kinds of compounds having one unsaturated group in one molecule. And a molecular weight of 3,000 to 60
One-component solder resist composition according to claim 1 or 2, which is a carboxyl group-containing photosensitive resin obtained by adding an acid anhydride to a reaction product of a copolymer of 000 and an unsaturated monobasic acid. . 5. The polymer compound or oligomer (A) is an unsaturated monobasic acid and one or more kinds in one molecule.
Molecular weight 3000 consisting of a compound having two unsaturated groups
The one-pack type solder according to claim 1 or 2, which is a carboxyl group-containing photosensitive resin obtained by adding a compound having one epoxy group and one unsaturated group in one molecule to a copolymer of -60,000. Resist composition. 6. The polymer compound or oligomer (A) comprises an unsaturated monobasic acid and one or more kinds in one molecule.
Molecular weight 3000 consisting of a compound having two unsaturated groups
The one-pack type solder resist composition according to claim 1 or 2, which is a carboxyl group-containing resin composed of a copolymer of ˜60,000. 7. The polymer compound or oligomer (A) is obtained by adding an acid anhydride to a reaction product of (a) a cresol novolac type epoxy compound or a phenol novolac type epoxy compound and an unsaturated monobasic acid. Carboxyl group-containing photosensitive resin, (b) molecular weight 3000 to 100 consisting of a compound having one epoxy group and one unsaturated group in one molecule and one or more kinds of compounds having one unsaturated group in one molecule A carboxyl group-containing photosensitive resin obtained by adding an acid anhydride to a reaction product of a copolymer of 60,000 and an unsaturated monobasic acid, (c) an unsaturated monobasic acid and 1
1 to a copolymer having a molecular weight of 3,000 to 60,000 comprising one or more types of compounds having one unsaturated group in one molecule
A carboxyl group-containing photosensitive resin obtained by adding a compound having one epoxy group and one unsaturated group in the molecule,
And (d) unsaturated monobasic acid and one or more kinds in one molecule
Molecular weight 3000 consisting of a compound having two unsaturated groups
The one-pack type solder resist composition according to claim 1 or 2, which is composed of a mixture of two or more kinds of carboxyl group-containing resins composed of -60,000 copolymers. 8. The method according to claim 1, further comprising 50 to 500 parts by weight of an inorganic filler with respect to 100 parts by weight of the polymer compound or oligomer (A). Liquid solder resist composition. 9. A polyfunctional unsaturated group-containing compound which is solid or semi-solid at room temperature is further included.
9. A one-pack type solder resist composition according to any one of items 1 to 8. 10. The one-component solder resist composition according to claim 1 is applied to a substrate, dried, and then exposed to active energy rays, and the unexposed portion is developed and removed. After that, it is a solder resist film that is cured by irradiation with active energy rays. 11. The one-component solder resist composition according to claim 1 is applied to a substrate, dried, and then exposed to active energy rays, and the unexposed portion is developed and removed. And a heat treatment at 100 to 150 ° C., or a heat treatment and irradiation with active energy rays to finish-cure the solder resist film.