JPH11184087A - Photosensitive additive adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive additive adhesive resin compsn. which allows via hole formation with good accuracy by photoimaging with development using an aq. alkaline soln., has excellent plating liquid resistance to electroless plating, has sufficient strength of adhesion to surface roughening of an adhesive and plating copper, has the heat resistance to withstand temp. around 260 deg.C of a soldering stage and is further used for production of multiplayered printed circuit boards having excellent flame retardance and a film composed of the same. SOLUTION: This photosensitive additive adhesive resin compsn. consists of (a) a mutlifunctional epoxy resin of 120 to 500 in epoxy equiv., (b) a brominated multifunctional epoxy resin of 120 to 500 in epoxy equiv. (c) denatured phenolic novolak formed by reacting 20 to 60% of phenolic hydroxl groups with glycidyl acrylate or glycidyl methacrylate, (d) diluting agent consisting of a multifunctional photopolymerizable monomer, (e) a photopolymn. initiator and (f) an inorg. filler. The film is formed by coating a carrier film with this compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive additive adhesive composition used for producing a multilayer printed wiring board by a build-up method and a film comprising the same.

[0002]

2. Description of the Related Art In a conventional method of manufacturing a multilayer printed wiring board, a circuit is first formed on a double-sided copper-clad board by etching.
The surface of the circuit is roughened, and one or more prepreg sheets that are semi-cured by impregnating a glass cloth base material with epoxy resin are stacked on top of one another, and a copper foil or single-sided copper-clad board is further stacked thereon,
This was a step of heating and integrating with a heating press. In this process, a glass cloth base material must be impregnated with epoxy resin and semi-cured once to make a prepreg sheet. there were. In addition, since the residual ratio of copper foil of the inner circuit board on which the circuit is formed is different, it is necessary to prepare various kinds of prepregs having different amounts of resin and melting behavior for adjusting the interlayer thickness. Since a glass cloth substrate was used, it was difficult and extremely expensive to make the interlayer thickness extremely thin.

[0003] In order to solve these problems, in recent years, various techniques have been reported in which a glass cloth substrate is not used for an interlayer insulating layer. For example, there is a method using a thermosetting epoxy resin coating or film, a polyimide resin coating or film, a heat-resistant film of a thermoplastic resin, or a photo-curable epoxy resin film.

In recent years, the density of multilayer printed wiring boards has been increased,
For miniaturization and weight reduction, not only fine circuit patterns but also surface via holes for conducting between circuit layers are required. When the surface via hole is machined with a mechanical drill, the hole machining with a diameter of about 300 μm is the limit, and when it is less than that, problems such as hole position accuracy and drill life will arise.

[0005] As in the prior art, a glass cloth substrate is impregnated with an epoxy resin and semi-cured to prepare a prepreg, and the copper foil and the heat and pressure are cured by pressing, a circuit is formed by etching, and then a mechanical drill is used. In the method of creating surface via holes, to use glass cloth,
There are problems such as the high cost, the problem that the thickness cannot be made extremely thin, and the problem that the surface via hole is formed by a mechanical drill, so that the fineness cannot be achieved. When excimer laser or carbon dioxide gas laser processing is used, a hole of about 50 μm can be formed. However, since it is not possible to perform overlapping processing like through through holes, the number of steps increases.

In order to solve these problems, a photosensitive interlayer insulating resin layer containing no glass cloth is formed on both sides or one side of an inner circuit board, and fine surface via holes are formed by photoimaging. Various photo-build-up methods for forming a circuit by panel plating and etching have been studied. The photosensitive interlayer insulating resin,
It must have excellent developability by a photographic method and have a function as an additive adhesive.

In general, in the additive method for manufacturing a substrate for consumer use, a thermosetting additive adhesive is often used. For example, JP-B-63-10752, JP-A-63-297571, and JP-A-63-297571. Kaisho 64-4
JP-A No. 7095, JP-A-3-18096 and the like include those in which an adhesive layer is roughened by an oxidizing agent, the contents of which include a rubber component such as acrylonitrile-butadiene rubber, and chromium-sulfuric acid as an oxidizing agent. The rubber component is eluted with an aqueous solution to roughen the surface of the adhesive.

Further, as disclosed in Japanese Patent Publication No. 4-79160, an inorganic fine powder such as silica or calcium carbonate is dispersed in a resin matrix having excellent heat resistance such as epoxy resin, phenol resin and melamine resin. A method for roughening an adhesive layer by selectively eluting the inorganic fine powder with a specific chemical as an adhesive, and a method disclosed in JP-A-1-294-1994.
As described in JP-A-79, a method of dispersing a cured epoxy resin fine powder having different solubility to an oxidizing agent in an epoxy resin matrix, and selectively eluting the epoxy resin fine powder with the oxidizing agent is known. is there. But,
When such a thermosetting additive adhesive is used, a surface via hole cannot be formed by photoimaging.

On the other hand, as disclosed in JP-A-5-136575, a method in which an epoxy resin is used for a matrix and a cationic photoinitiator is used as a curing agent,
As disclosed in JP-A-253730, there is a method of forming a surface via hole by photoimaging by using a phenol novolak type epoxy resin or an acrylate modified cresol novolak type epoxy resin as a matrix, but an organic solvent must be used for a developer. This is not preferable in terms of working environment.

[0010] Due to such demands, Japanese Patent Publication No. 7-494
As disclosed in JP-A-64, a curable composition comprising a compound having a phenolic hydroxyl group and an acryloyl group or a methacryloyl group in a molecule, an epoxy compound, and a photopolymerization initiator and performing a photoreaction and a thermal reaction is reported. However, the molecular weight of the compound having a phenolic hydroxyl group and an acryloyl or methacryloyl group in the molecule is small, and in alkali development using an aqueous solution of sodium hydroxide, the contrast, which is the balance between the dissolution rate and photosensitivity, is reduced. However, if the resolution is high, overexposure due to halation or surface deterioration due to a developing solution occurs.

[0011]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to form a via hole with high accuracy by photoimaging by developing using an alkaline aqueous solution, and to improve the plating solution resistance to electroless plating. Excellent, with sufficient adhesive strength between the roughened surface of the adhesive and the plated copper, with heat resistance to withstand temperatures around 260 ° C. in the soldering process, with excellent insulation properties, and with flame retardancy Another object of the present invention is to provide a photosensitive additive adhesive composition which is easy to form a photo via hole and is used for manufacturing a multilayer printed wiring board, and a film comprising the same.

[0012]

That is, the present invention provides:
A polyfunctional epoxy resin having an epoxy equivalent of 120 to 500,
(B) Brominated polyfunctional epoxy resin having an epoxy equivalent of 120 to 500 (c) Modified phenol novolak obtained by reacting 20 to 60% of phenolic hydroxyl groups with glycidyl acrylate or glycidyl methacrylate, and (d) polyfunctional photopolymerizable monomer A photosensitive additive adhesive composition comprising, as essential components, a diluent, (e) a photopolymerization initiator, and (f) an inorganic filler.

The present invention further relates to (a) an epoxy equivalent of 120
~ 500 polyfunctional epoxy resin, (b) epoxy equivalent 1
20 to 500 brominated polyfunctional epoxy resin (C) Polyfunctional phenol obtained by condensing bisphenol A or bisphenol F with formaldehyde under an acidic catalyst, wherein 20 to 60% of phenolic hydroxyl groups are glycidyl acrylate or glycidyl. Modified bisphenol novolak reacted with methacrylate, (d) a diluent composed of a polyfunctional photopolymerizable monomer, (e) a photopolymerization initiator,
(F) A photosensitive additive adhesive composition comprising an inorganic filler as an essential component.

The polyfunctional epoxy resin having an epoxy equivalent of 120 to 500 as the component (a) used in the present invention is preferably a bisphenol A type epoxy resin or a bisphenol F type epoxy resin. When the epoxy equivalent is larger than 500, an alkaline aqueous solution is used. Is not preferred in terms of developability using

(B) Epoxy equivalent of component: 120 to 500
Examples of the brominated polyfunctional epoxy resin include a brominated phenol novolak epoxy resin, a brominated bisphenol A type epoxy resin and a bisphenol F type epoxy resin. If the epoxy equivalent is larger than 500, it is not preferable in terms of developability using an aqueous alkali solution.

The phenol novolak of the component (c) is a phenol novolak obtained by condensing a phenol compound having one or two phenolic hydroxyl groups in a molecule with formaldehyde under an acidic catalyst, and an acrylate having a glycidyl group. It is obtained by reacting with methacrylate. In order to obtain a permanent resist with good pattern accuracy, which has excellent alkali developability after photopolymerization,
An epoxy group of acrylate or methacrylate having a glycidyl group is preferably 0.2 to 0.6 equivalent to 1 equivalent of hydroxyl group of phenol novolak. When it is 0.2 equivalent or less, the photocurability is poor, and even if photocuring is performed by irradiating ultraviolet rays, it is dissolved in a developing solution and resolution cannot be exhibited. On the other hand, if it is 0.6 equivalent or more, the alkali solubility is poor, and even if it is not photocured, it does not dissolve in the developing solution, so that the resolution is also lost. Therefore, it is necessary to react 20 to 60% of the phenolic hydroxyl group of phenol novolak with glycidyl acrylate or glycidyl methacrylate in order to increase the contrast of solubility in an aqueous alkali solution and to achieve high resolution by photocuring. And more preferably 40 to 50%.

Further, in order to enhance the contrast of development, the phenolic hydroxyl group of novolak obtained by condensing bisphenol A or bisphenol F having two phenolic hydroxyl groups in the molecule with formaldehyde in the presence of an acidic catalyst is preferably 20 to 20%. Preferred is a modified bisphenol novolak in which 60% has been reacted with glycidyl acrylate or glycidyl methacrylate. This is because even if the molecular weight is increased, the change in the dissolution rate is small, and the sensitivity can be increased. Although the reason is not clear, it is considered that the intramolecular motion of bisphenol novolak is restricted, and the aggregation of the hydrophilic group and the hydrophobic group due to the polymerization is small. Other bisphenol compounds having two phenolic hydroxyl groups in the molecule include bisphenol S type. As the acrylate or methacrylate having a glycidyl group, glycidyl acrylate or glycidyl methacrylate is preferable because of its reactivity, availability, and the like.

(D) Examples of the diluent comprising a polyfunctional photopolymerizable monomer include compounds having at least two or more acryloyl groups or methacryloyl groups in one molecule. For example, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,4
-Butanediol dimethacrylate, 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, glycerol diacrylate, neopentyl glycol diacrylate Acrylate, bisphenol A diacrylate and the like. Preferred monomers are tri- or 4-functional trimethylolpropane triacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate having good developer resistance after photocuring. These polyfunctional photopolymerizable monomers have a high photoreaction speed and can be photocured to a deep part with a small amount of energy irradiation, so they have high resolution, there is no deterioration of the developer in the photocured portion, and even in high aspect photo via holes. , Without undercut. Furthermore, in order to improve the chemical resistance after heat curing, glycidyl acrylate or glycidyl methacrylate that can react with a carboxylic acid or a phenolic hydroxyl group can be used. These polyfunctional photopolymerizable monomers may be used alone or in combination, and the blending amount can be determined according to the balance between the development characteristics and the cured product characteristics.

(E) Examples of the photopolymerization initiator include benzophenones such as benzophenone, benzoylbenzoic acid, 4-phenylbenzophenone and hydroxybenzophenone, benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether,
Benzoin alkyl ethers such as benzoin isobutyl ether and benzyl dimethyl ketal, acetophenones such as 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 4-t-butyl-trichloroacetophenone, and diethoxyacetophenone; thioxanthone; Chlorthioxanthone, 2
Thioxanthones such as -methylthioxanthone, 2,4-dimethylthioxanthone, ethylanthraquinone,
Alkyl anthraquinones such as butyl anthraquinone and the like can be mentioned. These can be used alone or 2
Used as a mixture of more than one species. The addition amount of the photopolymerization initiator is usually used in the range of 0.1 to 10% by weight.

(F) Examples of the inorganic filler include silica, talc, clay, calcium carbonate, aluminum hydroxide, zinc oxide, barium sulfate and the like. Of these, barium sulfate is preferable, and 20% of the total adhesive composition is used. It is used in a range of not less than% by weight.

In the present invention, an organic solvent is added as required. Organic solvents include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; cell sorbs such as methyl cellosolve, ethyl cellosolve and butyl cellosolve; Such as carbitols, propylene glycol monomethyl ether, propylene glycol dimethyl ether,
Glycol ethers such as dipropylene glycol monoethyl ether and triethylene glycol monoethyl ether; and acetates such as ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, and the like. Even if these are used alone, 2
You may use in combination of 2 or more types. The purpose of using these organic solvents is to dissolve phenol novolak which is a solid component (c), and to volatilize the solvent by heating and drying the liquid resin composition applied on the inner layer substrate to make it tack-free. The reason for this is to adjust the viscosity to an appropriate resin viscosity in order to coat the carrier film and evaporate the solvent to form a dry film.

In these resin compositions, radicals are generated from the photopolymerization initiator of the component (e) by ultraviolet irradiation, and polymerize between the acryloyl group or the methacryloyl group of the components (c) and (d). Then, by heating,
The glycidyl group of component (a) and component (b) and the phenolic hydroxyl group of component (c) are polymerized and thermally cured. At this time,
If (d) has a hydroxyl group or a glycidyl group,
It polymerizes with the glycidyl groups of components (a) and (b).

[0023] In addition, the photosensitive additive adhesive composition of the present invention may optionally contain an ultraviolet inhibitor, a thermal polymerization inhibitor, a plasticizer, and the like for storage stability. or,
An acrylate monomer, a methacrylate monomer, a vinyl monomer, or the like may be added for adjusting the viscosity.

The photosensitive additive adhesive composition of the present invention comprising these components has high resolution and excellent developability with an aqueous alkali solution. In particular, the solubility in an alkaline aqueous solution is mainly the phenolic hydroxyl group of phenol novolak in which an acryloyl group or a methacryloyl group is introduced into 20 to 60% of the phenolic hydroxyl group of the component (c). As described above, the photo-cured product in which these functional groups remain is a cured product having poor alkali resistance, chemical resistance, and electrical properties, but the photosensitive additive adhesive composition of the present invention is not cured by photo-curing. After the development, the thermosetting reaction is the main component of the resin composition. By the subsequent heat treatment, the epoxy resin of the component (a) is converted into the phenolic hydroxyl group in the component (c) and the hydroxyl group in the component (d). Alternatively, it reacts with a glycidyl group by thermosetting to form a main skeleton excellent in required characteristics. Therefore, it is an additive adhesive cured product that withstands electroless plating performed for a long time under high temperature and high alkalinity conditions and has excellent adhesion to plated copper.

[0025]

EXAMPLES << Synthesis Example 1 >> [Synthesis of phenol novolak type thermosetting agent containing methacryloyl group] As a phenol novolak type thermosetting agent, phenolite TD-2090-60M (manufactured by Dainippon Ink and Chemicals, Inc.)
A non-volatile content of 60% and a MEK cut of 700 g (about 4 equivalents of OH) were charged into a 2-liter flask, and tributylamine 1 was added.
g and hydroquinone 0.2 g were added and heated to 110 ° C. The glycidyl methacrylate 284g (2
Mol) was added dropwise over 30 minutes, followed by a stirring reaction at 110 ° C. for 5 hours.

<< Synthesis Example 2 >> [Synthesis of Methacryloyl Group-Containing Bisphenol A Novolak] As a bisphenol A novolak, phenolite LF was used.
-4871 (manufactured by Dainippon Ink and Chemicals, Inc .: nonvolatile content 60
% Methyl ethyl ketone solution) 800 g (OH about 4 equivalents)
Into a 2 liter flask, and 0.2 g of hydroquinone is added.
And 284 g (2 mol) of glycidyl methacrylate were added, and the mixture was heated to 110 ° C. Tributylamine 1
After adding g, the mixture was stirred and reacted at 110 ° C. for 5 hours.

<< Example 1 >> 10 g of Epicoat 828,
BREN-S (Nippon Kayaku Co., Ltd .: Epoxy equivalent 275, B
15g, 50 g of a methacryloyl group-containing phenol novolak type thermosetting agent of Synthesis Example 1, 15 g of 1,4-butanediol diacrylate, and 30 g of barium sulfate.
g and kneaded with a three-roll mill, 3 g of Irgacure 651 (manufactured by Ciba-Geigy) as a photoinitiator and 0.2 g of triphenylphosphine as a thermosetting accelerator.
Was added to obtain a photosensitive additive adhesive composition.

Example 2 10 g of Epicoat 828,
15 g of BREN-S, 50 g of a methacryloyl group-containing bisphenol A novolak type thermosetting agent of Synthesis Example 2, 1,
15 g of 4-butanediol diacrylate and 30 g of barium sulfate were mixed and kneaded with a three-roll mill, and Irgacure 651 (manufactured by Ciba-Geigy) was used as a photoinitiator.
g and triphenylphosphine as thermosetting accelerator
0.2 g was added to obtain a photosensitive additive adhesive composition.

Example 3 10 g of Epicoat 828,
15 g of Epicoat 5050 (manufactured by Yuka Shell Epoxy Co., Ltd .: epoxy equivalent: 395, Br conversion ratio: 49%), 50 g of a methacryloyl group-containing phenol novolak type thermosetting agent of Synthesis Example 1, 15 g of 1,4-butanediol diacrylate
And 30 g of barium sulfate were mixed and kneaded with a three-roll mill, and 3 g of Irgacure 651 (manufactured by Ciba-Geigy) as a photoinitiator and 0.2 g of triphenylphosphine as a thermosetting accelerator were added. An adhesive composition was obtained.

Example 4 10 g of Epicoat 828,
Epicoat 5050 15 g, methacryloyl group-containing phenol novolak-type thermosetting agent of Synthesis Example 2 50 g, 1,
15 g of 4-butanediol diacrylate and 30 g of barium sulfate were mixed and kneaded with a three-roll mill, and Irgacure 651 (manufactured by Ciba-Geigy) was used as a photoinitiator.
g and triphenylphosphine as thermosetting accelerator
0.2 g was added to obtain a photosensitive additive adhesive composition.

Comparative Example 1 Epicoat 828 20 g,
50 g of the methacryloyl group-containing phenol novolak type thermosetting agent of Synthesis Example 1, 15 g of 1,4-butanediol diacrylate and 30 g of barium sulfate were mixed and kneaded with a three-roll mill, and Irgacure 651 was used as a photoinitiator.
3 g (Ciba-Geigy) and 0.2 g of triphenylphosphine as a thermosetting accelerator were added to obtain a photosensitive additive adhesive composition.

Comparative Example 2 Epicoat 828 20 g,
50 g of the methacryloyl group-containing phenol novolak type thermosetting agent of Synthesis Example 2, 15 g of 1,4-butanediol diacrylate and 30 g of barium sulfate were mixed and kneaded with a three-roll mill, and Irgacure 651 was used as a photoinitiator.
3 g (Ciba-Geigy) and 0.2 g of triphenylphosphine as a thermosetting accelerator were added to obtain a photosensitive additive adhesive composition.

[Preparation of Additive Method Multilayer Printed Wiring Board] Laminated board with catalyst-containing adhesive obtained by subjecting the photosensitive additive adhesive compositions obtained in Examples 1 to 4 and Comparative Examples 1 and 2 to a catalyst activation treatment. Apply on top with a thickness of 30 μm, 8
Heat treatment was performed at 0 ° C. for 20 minutes. However, in Comparative Example 1, the cover film was brought into contact with the adhesive composition because the liquid composition had a tack after the heat treatment. A predetermined pattern was placed on this laminate, and the laminate was exposed at a dose of 200 mJ / cm ² using a high-pressure mercury lamp exposure apparatus. Subsequently, development was carried out with a sodium hydroxide aqueous solution at a spray pressure of ² kg / m ² . After washing and drying, the entire surface was post-exposed to 1 J / cm ² and
Heat treatment was performed at 0 ° C. for 60 minutes. This was immersed in an electroless copper plating solution at 70 ° C. for 10 hours to form an electroless copper plating film of about 20 μm, thereby producing an additive multilayer printed wiring board.

The properties of the photosensitive additive adhesive composition in the process of obtaining the additive-processed multilayer printed wiring board in this manner were evaluated. The results are shown in Table 1. Table 1 現 像 Developability Solvent resistance Plating solution resistance Solder heat resistance Flame retardant ─ ─────────────────────────────── Example 1 ○ ○ ○ ○ V-0 Example 2 ○ ○ ○ ○ V- 0 Example 3 △ ○ ○ ○ V-0 Example 4 △ ○ △ △ V-0 ───────────────────────────── ─── Comparative Example 1 ○ ○ ○ ○ × Comparative Example 2 ○ ○ ○ ○ × ─────────────────────────────── ─

<< Measurement Method >> Developability ：: Developed △: Slight development residue ×: Develop residue left ・ Solvent resistance Presence / absence of change in acetone immersion for 20 minutes ○: No change observed △: slightly changed ×: changed ・ Plating solution resistance Presence / absence of change in electroless copper plating process ○: No change observed △: slightly changed ×: changed ・ Solder heat resistance n = 5 All changed at 260 ° C for 20 seconds ○: No change △: Some change ×: Change ・ Flame retardancy According to UL standard Pass: VO ×: Combustion up to clamp

[0036]

As described above, the photosensitive additive adhesive composition for a printed wiring board of the present invention and the cured product thereof have high resolution and are easy to be developed with an aqueous alkali solution. Excellent solvent resistance to alcohol, trichloroethylene, methylene chloride, acetone, etc., excellent plating solution resistance to electroless plating performed for a long time under high temperature and high alkalinity conditions, and heat resistance to withstand temperatures around 260 ° C in the soldering process And a printed wiring board having excellent flame retardancy.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G03F 7/027 502 G03F 7/027 502 (72) Inventor Masao Uesaka 2-5-8 Higashishinagawa, Shinagawa-ku, Tokyo Sumitomo Bakelite Co., Ltd. In company

Claims (4)

[Claims] 1. A polyfunctional epoxy resin having an epoxy equivalent of 120 to 500, (b) a brominated polyfunctional epoxy resin having an epoxy equivalent of 120 to 500, and c) glycidyl acrylate or glycidyl containing 20 to 60% of the phenolic hydroxyl groups. Modified phenol novolak reacted with methacrylate, (d) diluent composed of polyfunctional photopolymerizable monomer, (e) photopolymerization initiator, and (f) inorganic filler as essential components. Composition. 2. A polyfunctional epoxy resin having an epoxy equivalent of 120 to 500, a brominated polyfunctional epoxy resin having an epoxy equivalent of 120 to 500, and c) bisphenol A or bisphenol F condensed with formaldehyde in the presence of an acidic catalyst. A modified bisphenol novolak obtained by reacting 20 to 60% of phenolic hydroxyl groups with glycidyl acrylate or glycidyl methacrylate, (d) a diluent comprising a polyfunctional photopolymerizable monomer, A photosensitive additive adhesive composition comprising a photopolymerization initiator and (f) an inorganic filler as essential components. 3. A photosensitive additive adhesive film for a printed wiring board, wherein the photosensitive additive adhesive composition according to claim 1 is applied to a carrier film and formed into a film. 4. A photosensitive additive adhesive film for a printed wiring board, wherein the photosensitive additive adhesive composition according to claim 2 is applied to a carrier film to form a film.