JPH10186656A - Resin composition, permanent resist resin composition and their cured bodies - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a permanent resist having high resolution, easy to develop with an aq. alkali soln. and excellent also in resistance to a plating soln. for electroless plating which is carried out at a high temp. under high alkali conditions for a long time and to produce a printed circuit board having heat resistance up to about 260 deg.C temp. in a soldering process. SOLUTION: The objective resin compsn. and permanent resist resin compsn. contain multifunctional epoxy resin having an epoxy equiv. of 120-500, modified phenol novolak obtd. by allowing 20-60% of the phenolic hydroxyl groups of phenol novolak with glycidyl acrylate or glycidyl methacrylate, an epoxy acrylate or epoxy methacrylate compd., a diluent made of a photo- multifunctional monomer and a photopolymn. initiator as essential components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin composition useful as a permanent resist for a printed wiring board, and a cured product thereof.

[0002]

2. Description of the Related Art Conventionally, printed wiring boards have been manufactured using a copper-clad laminate and by a subtractive method of removing unnecessary portions of the copper foil circuit by etching. It has drawbacks such as difficulty in forming high-density wiring boards, and the inability to uniformly form small-diameter through holes and via holes by electroplating. That is the current situation.

On the other hand, recently, a full additive method of forming an adhesive layer on a laminate made of an insulating base material and forming a circuit and a through hole by electroless plating has attracted attention. In this method, the conductor pattern accuracy is determined only by the transfer accuracy of the plating resist, and since the conductor portion is formed only by electroless plating, even in a substrate having a high aspect ratio through hole, a uniform through hole having a high throwing power is obtained. Plating can be performed. Until now, the additive method has been considered suitable for general consumer use, but is beginning to be put into practical use as an industrial, high-density, high-multilayer substrate manufacturing process.

[0004]

Generally, in an additive method for manufacturing a substrate for consumer use, a plating resist pattern is transferred by a screen printing method. ,
It is necessary to form a plating resist pattern by photolithography, that is, to employ a photo-additive method using a photoresist. Photoresists suitable for photoadditive methods include sensitivity, resolution,
In addition to the inherent properties of photoresist such as developability, the following properties are required. Since development is limited to 1,1,1-trichloroethane-based organic solvents or aqueous alkali solutions, development must be possible with either. Withstands electroless plating performed for a long time under high temperature and high alkalinity conditions, has excellent solder resist characteristics as a permanent resist after plating, and has a 260
It has heat resistance to withstand temperatures around ℃.
The reason is that the thermal reliability of the entire substrate is not reduced even if the layers are stacked. At present, photoresists that can be used in the additive method are commercially available, but are still not sufficient.

[0005] 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, since the molecular weight of the compound having a phenolic hydroxyl group and an acryloyl group or a 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.
Although development is possible with low resolution, high resolution causes overexposure due to halation or surface deterioration due to a developing solution. Therefore, an object of the present invention is to form a high-resolution resist by a photographic method by development using an alkaline aqueous solution, sufficiently withstand the electroless copper plating solution of the full additive method, and It is intended to provide a permanent resist resin composition which has heat resistance to withstand temperatures of around 260 ° C. and is used without removing it to the final product, and a cured product thereof.

[0006]

In order to achieve the above object, a resin composition, a permanent resist resin composition for a printed wiring board, and a cured product thereof according to the present invention have the following composition, and are used as a permanent resist. It is characterized in that it has excellent characteristics and that a printed wiring board using this resist resin composition can be manufactured.

That is, the present invention provides the following component (a):
The present invention relates to a resin composition comprising (B), (C), (D) and (E) as essential components, a permanent resist resin composition for a printed wiring board, and a cured product thereof. (A) a polyfunctional epoxy resin having an epoxy equivalent of 120 to 500, (b) a modified phenol novolak obtained by reacting 20 to 60% of phenolic hydroxyl groups with glycidyl acrylate or glycidyl methacrylate, (c) an epoxy acrylate or epoxy methacrylate compound,
(D) a diluent comprising a photo-functional monomer, and (e) a photopolymerization initiator.

The epoxy resin (a) used in the present invention is preferably a bisphenol A type (or F type) epoxy resin, and if the average molecular weight is more than 1,000, it is preferable in terms of developability using an alkaline aqueous solution. Absent.

The phenol novolak of the component (b) is a phenol novolak obtained by condensing a phenol compound having one or two phenolic hydroxyl groups in the 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 excellent pattern developability and excellent alkali developability after photopolymerization, an epoxy group of acrylate or methacrylate having a glycidyl group with respect to 1 equivalent of a hydroxyl group of phenol novolak is used. Six equivalents are suitable. 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 photo-cured, 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%
It is.

In order to enhance the development contrast, novolaks obtained by condensing bisphenol A or F having two phenolic hydroxyl groups in the molecule with formaldehyde in the presence of an acidic catalyst have a phenolic hydroxyl group of 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 when the molecular weight is increased, the change in the dissolution rate is small, and the sensitivity during development 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 increase in the molecular weight 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.

(C) The epoxy acrylate or epoxy methacrylate compound is not particularly limited, but includes a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, a bisphenol S type epoxy compound, a phenol novolak type epoxy compound,
It is obtained by reacting an epoxy compound such as a cresol novolak type epoxy compound or an aliphatic epoxy compound with acrylic acid or methacrylic acid. When the purpose is to improve the alkali water solubility or the adhesion to an insulating substrate or a metal, the following method may be performed. (1)
After the reaction (reaction of the epoxy compound with acrylic acid or methacrylic acid), an acid value such as oxalic acid, malonic acid, succinic acid, glutamic acid, adipic acid, maleic acid, fumaric acid, phthalic acid or terephthalic acid 5-10
With a dicarboxylic acid compound or anhydride thereof.
Alternatively, (2) leaving the epoxy group of the epoxy compound in the above reaction in an amount corresponding to the subsequent carboxylic acid modification, and then oxalic acid, malonic acid, succinic acid, glutamic acid, adipic acid, maleic acid, fumaric acid, phthalic acid It can be reacted with a dicarboxylic acid having an acid value of 5 to 100 or an anhydride thereof, such as an acid or terephthalic acid. At this time, if the acid value is small, the alkali water solubility is deteriorated, and if it is too large, it becomes a factor for deteriorating the resist properties such as chemical resistance and electrical properties during curing.

(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 multifunctional 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, do not deteriorate the photocured part of the developing solution, and develop even at a high aspect ratio. Later side surfaces of the resist are linear, and undercuts and the like can be prevented.

(E) Examples of photopolymerization initiators 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.

In these resin compositions, radicals are generated from the photopolymerization initiator of the component (e) by irradiation with ultraviolet rays, and the radicals are generated between the acryloyl group or the methacryloyl group of the components (b), (c) and (d). Polymerizes at Next, by heating, the glycidyl group of the component (a) and the phenolic hydroxyl group of the component (b) are polymerized and thermally cured. At this time,
If the component (c) has a carboxylic acid group, it polymerizes with the glycidyl group of the component (a).

In addition, an ultraviolet absorber, a thermal polymerization inhibitor, or a plasticizer for storage stability can be added to the permanent resist of the present invention, if necessary. The permanent resist resin composition of the present invention comprising these components has high resolution and excellent developability with an aqueous alkaline 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 (b), and the epoxy acrylate of the component (c) Alternatively, when the epoxy methacrylate compound has a carboxylic acid group, the solubility is further enhanced. As described above, the photo-cured product in which these functional groups remain becomes a resist having poor alkali resistance, chemical resistance, and electrical properties, but the permanent resist resin composition of the present invention is obtained after photo-curing and developing. Is a resin composition mainly composed of a thermosetting reaction, and the subsequent heat treatment causes the epoxy resin of the component (a) to be thermally cured with the phenolic hydroxyl group of the component (b) and the carboxylic acid group of the component (c). It reacts to form a main skeleton excellent in required characteristics. Therefore, the permanent resist cured product can withstand electroless plating performed for a long time under high temperature and high alkalinity conditions.

The permanent resist resin composition according to the present invention comprises
A resist layer is formed by applying a 20 to 60 μm thickness on the adhesive for full additive, and tack-free or prepolymerized by heating at 60 to 100 ° C. for about 5 to 30 minutes. Alternatively, a film-like material which has been previously coated on a carrier film and made tack-free or prepolymerized under the same conditions as described above may be laminated on the adhesive layer.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.

(Synthesis Example 1) Synthesis of phenol novolak containing methacryloyl group As phenol novolak, phenolite TD-20 was used.
90-60M (manufactured by Dainippon Ink and Chemicals, Inc .: nonvolatile content 6)
700 g (about 4 equivalents of OH) of a 0% methyl ethyl ketone solution was charged into a 2 liter flask, and hydroquinone was added in an amount of 0.1%.
2 g and 284 g (2 mol) of glycidyl methacrylate were added and heated to 110 ° C. After 1 g of tributylamine was added thereto, the mixture was stirred and reacted at 110 ° C for 5 hours.

(Synthesis Example 2) Synthesis of phenol novolak containing methacryloyl group As phenol novolak, phenolite TD-20 was used.
700 g of 90-60M (about 4 equivalents of OH) was charged into a 2 liter flask, and 0.2 g of hydroquinone and 398 g (2.8 mol) of glycidyl methacrylate were added.
Warmed to ° C. After 1 g of tributylamine was added thereto, the mixture was stirred and reacted at 110 ° C for 5 hours.

(Synthesis Example 3) 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.

(Synthesis Example 4) Synthesis of methacryloyl group-containing bisphenol A novolak As a bisphenol A novolak, phenolite LF was used.
-4871 800 g (about 4 equivalents of OH) was charged into a 2 liter flask, and 0.2 g of hydroquinone and 398 g (2.8 mol) of glycidyl methacrylate were added.
Was heated. After 1 g of tributylamine was added thereto, the mixture was stirred and reacted at 110 ° C for 5 hours.

(Synthesis Example 5) Synthesis of carboxyl group-containing epoxy acrylate In a 2 l flask, 760 g (4 equivalents) of bisphenol A type epoxy resin Epicoat 828 (manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent: 190) and methoxy as a polymerization inhibitor were used. After adding 1 g of phenol, 288 g of acrylic acid
(4 moles), 1 g of benzyldimethylamine was added and 10
The reaction was stirred at 0 ° C. for 6 hours. Then, succinic anhydride 1
60 g (1.6 mol) was added, and the mixture was stirred and reacted at 80 ° C. for 3 hours.

Example 1 100 parts by weight of a methacryloyl group-containing phenol novolak of Synthesis Example 1, 15 parts by weight of a carboxyl group-containing epoxy acrylate of Synthesis Example 5, 10 parts by weight of pentaerythritol triacrylate, and 25 parts by weight of Epicoat 828 were mixed. As a photoinitiator
5 parts by weight of Irgacure 651 (manufactured by Ciba-Geigy) and 0.2 parts by weight of triphenylphosphine as a thermosetting accelerator were added and stirred well to obtain a permanent resist resin composition.

Example 2 100 parts by weight of methacryloyl group-containing phenol novolak of Synthesis Example 1, 15 parts by weight of epoxy acrylate SP-4010 (manufactured by Showa Polymer Co., Ltd.), 10 parts by weight of pentaerythritol triacrylate, and 25 parts by weight of Epicoat 828 And 5 parts by weight of Irgacure 651 as a photoinitiator and 0.2 parts by weight of triphenylphosphine as a thermosetting accelerator were added and stirred well to obtain a permanent resist resin composition.

Example 3 100 parts by weight of methacryloyl group-containing bisphenol novolak of Synthesis Example 3, Synthesis Example 5
Of carboxyl group-containing epoxy acrylate, 10 parts by weight of pentaerythritol triacrylate and 25 parts by weight of Epicoat 828, 5 parts by weight of Irgacure 651 as a photoinitiator and 0.2 parts by weight of triphenylphosphine as a thermal curing accelerator Was added and stirred well to obtain a permanent resist resin composition.

Example 4 100 parts by weight of the methacryloyl group-containing bisphenol novolak of Synthesis Example 3, 15 parts by weight of epoxy acrylate SP-4010, 10 parts by weight of pentaerythritol triacrylate and 25 parts by weight of Epicoat 828 were mixed, and a photoinitiator was mixed. 5 parts by weight of Irgacure 651 and 0.2 parts by weight of triphenylphosphine as a thermosetting accelerator were added and stirred well to obtain a permanent resist resin composition.

Comparative Example 1 A resist resin composition was prepared by mixing 100 parts by weight of the carboxyl group-containing epoxy acrylate of Synthesis Example 5 and 20 parts by weight of pentaerythritol triacrylate and adding 5 parts by weight of Irgacure 651 as a photoinitiator. And

Comparative Example 2 100 parts by weight of the methacryloyl group-containing phenol novolak of Synthesis Example 2, 15 parts by weight of the carboxyl group-containing epoxy acrylate of Synthesis Example 5, 10 parts by weight of pentaerythritol triacrylate, and 25 parts by weight of Epicoat 828 were mixed. As a photoinitiator
5 parts by weight of Irgacure 651 and a thermosetting accelerator
Triphenylphosphine (0.2 part by weight) was added and stirred well to obtain a permanent resist resin composition.

Comparative Example 3 100 parts by weight of a methacryloyl group-containing bisphenol novolak of Synthesis Example 4, Synthesis Example 5
Of carboxyl group-containing epoxy acrylate, 10 parts by weight of pentaerythritol triacrylate and 25 parts by weight of Epicoat 828, 5 parts by weight of Irgacure 651 as a photoinitiator and 0.2 parts by weight of triphenylphosphine as a thermal curing accelerator Was added and stirred well to obtain a permanent resist resin composition.

Comparative Example 4 100 parts by weight of the methacryloyl group-containing phenol novolak of Synthesis Example 1, 15 parts by weight of the carboxyl group-containing epoxy acrylate of Synthesis Example 5 and 82825 parts by weight of Epicoat were mixed, and used as a photoinitiator.
5 parts by weight of Irgacure 651 and a thermosetting accelerator
Triphenylphosphine (0.2 part by weight) was added and stirred well to obtain a permanent resist resin composition.

Comparative Example 5 100 parts by weight of bisphenol novolak containing methacryloyl group of Synthesis Example 3, Synthesis Example 5
Of carboxyl group-containing epoxy acrylate and 25 parts by weight of Epicoat 828 were added, and 5 parts by weight of Irgacure 651 as a photoinitiator and 0.2 parts by weight of triphenylphosphine as a thermal curing accelerator were added, followed by thorough stirring. , A permanent resist resin composition.

[Production of Additive Method Multilayer Printed Wiring Board] The resin compositions obtained in Examples 1 to 4 and Comparative Example were
It was applied to a thickness of 40 μm on a laminated plate with a catalyst-containing additive adhesive that had been subjected to a catalyst activation treatment, and was heat-treated at 80 ° C. for 20 minutes. However, in Comparative Example 1, since the liquid was tacky even after this heat treatment, a cover film that transmits ultraviolet light was brought into contact with the resist. A pattern of 50 μm line and 50 μm space is placed on this laminate,
Exposure was performed using a high-pressure mercury lamp exposure apparatus at an irradiation amount of 200 mJ / cm ² . Subsequently, development was carried out with a 1.5% aqueous sodium hydroxide solution at 25 ° C. at a spray pressure of ² kg / m ² . After washing and drying, the entire surface was post-exposed at 1 J / cm ² to 150
C. for 30 minutes. This was immersed in an electroless copper plating solution (KC-500 manufactured by Japan Energy) at 70 ° C. for 5 hours to form an electroless copper plating film of about 25 μm. Thereafter, the resultant was dried by heating at 150 ° C. for 1 hour to produce an additive method multilayer printed wiring board.

Table 1 shows the results of evaluating the resist characteristics in the process of obtaining the additive multilayer printed wiring board in this manner.

(Evaluation method) Dissolution time: The time until all the unexposed resin composition was not dissolved was measured. Number of curing steps: A 21-step Stofa step tablet was exposed in close contact, developed for twice the dissolution time of each, and the number of curing steps at which no surface deterioration was observed was observed. (Does not apply to those insoluble in the developer.) Line shape: Develop for twice the dissolution time,
After post-exposure and thermosetting, the cross-sectional shape was observed. (The insoluble in the developing solution was not used.) Moisture-absorbing solder heat resistance: The prepared multilayer printed wiring board was subjected to a moisture absorption treatment at 121 ° C. for 1 hour with a saturated pressure cooker.
It was immersed in the solder at 0 ° C. for 20 seconds. The time until each sample of n = 5 was destroyed was measured, and the average time was calculated. Plating solution resistance: The appearance of the prepared additive method multilayer printed wiring board was observed.も の indicates that no change was observed in the electroless copper plating process, and x indicates that change was observed.

Table 1 ─────────────────────────────────── Melting time Number of curing stages Line shape Moisture absorption solder heat resistance Plating solution resistance (sec) (step) (cross-sectional shape) (sec) ─────────────────────────────────実 施 Example 1 254 Straight 20 ○ Example 2 35 5 Straight 20 ○ Example 3 30 5 Straight 20 ○ Example 4 406 Straight 20 ○ Comparative Example 1 203 3 Straight 20 × Comparative Example 2 Insoluble--20 ○ Comparative Example 3 Insoluble--20 ○ Comparative Example 4 30 2 Undercut 20 ○ Comparative Example 5 35 2 Undercut 20 ○ ──────────────────────── ───────────

[0036]

As described above, the resin composition of the present invention is photopolymerized and cured by heating to obtain a cured product having excellent heat resistance. And, the permanent resist resin composition for a printed wiring board of the present invention and the cured product thereof have high resolution, and despite being easy to develop with an aqueous alkali solution,
Excellent plating solution resistance to electroless plating performed for a long time under high temperature and high alkalinity conditions. Furthermore, it has heat resistance to withstand temperatures around 260 ° C in the soldering process. The production of a printed wiring board excellent in the above was enabled.

Claims (5)

[Claims] 1. The following components (a), (b), (c),
A resin composition comprising (d) and (e) as essential components. (A) a polyfunctional epoxy resin having an epoxy equivalent of 120 to 500, (b) a modified phenol novolak obtained by reacting 20 to 60% of phenolic hydroxyl groups with glycidyl acrylate or glycidyl methacrylate, (c) an epoxy acrylate or epoxy methacrylate compound,
(D) a diluent comprising a photo-functional monomer, and (e) a photopolymerization initiator. 2. The following components (a), (b), (c),
A resin composition comprising (d) and (e) as essential components. (A) a polyfunctional epoxy resin having an epoxy equivalent of 120 to 500, and (b) a polyfunctional phenol obtained by condensing bisphenol A or F with formaldehyde under an acidic catalyst, wherein 20 to 60% of phenolic hydroxyl groups are glycidyl. Modified bisphenol novolak reacted with acrylate or glycidyl methacrylate, (c) epoxy acrylate or epoxy methacrylate compound,
(D) a diluent comprising a photo-functional monomer, and (e) a photopolymerization initiator. 3. The following components (a), (b), (c),
A permanent resist resin composition for a printed wiring board, comprising (d) and (e) as essential components. (A) a polyfunctional epoxy resin having an epoxy equivalent of 120 to 500, (b) a modified phenol novolak obtained by reacting 20 to 60% of phenolic hydroxyl groups with glycidyl acrylate or glycidyl methacrylate, (c) an epoxy acrylate or epoxy methacrylate compound,
(D) a diluent comprising a photo-functional monomer, and (e) a photopolymerization initiator. 4. The following components (a), (b), (c),
A permanent resist resin composition for a printed wiring board, comprising (d) and (e) as essential components. (A) a polyfunctional epoxy resin having an epoxy equivalent of 120 to 500, and (b) a polyfunctional phenol obtained by condensing bisphenol A or F with formaldehyde under an acidic catalyst, wherein 20 to 60% of phenolic hydroxyl groups are glycidyl. Modified bisphenol novolak reacted with acrylate or glycidyl methacrylate, (c) epoxy acrylate or epoxy methacrylate compound,
(D) a diluent comprising a photo-functional monomer, and (e) a photopolymerization initiator. 5. A cured product of the resin composition according to claim 1, 2, 3, or 4.