JPH01253730A - Photosensitive resin composition - Google Patents

Abstract

PURPOSE:To form an insulating layer between org. layers capable of improving the heat-resisting and the electric insulating properties and the sticking property of a film by composing the title composition of a specified photopolymerizable compd., a specified polymerizable compd. and a specified fine particle filler. CONSTITUTION:The photopolymerizable compd. which is composed of at least one kind of a compd. shown by formula I and has one or more of epoxy groups modified with (meth)acrylic acid, the polymerizable compd. having at least two or more of end-ethylenic groups, the photopolymerization initiator capable of generating a radical by an active ray, an epoxy curing agent and the fine particle filler capable of being dissolved and removed by a chemical treatment are incorporated in the photosensitive resin composition. The good insulating layer between the org. layers with the improved heat-resisting and electric insulating properties and sticking property of the film can be obtd. by using the photosensitive resin composition for the insulating layer. In the formula, (n) is >=1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a photosensitive resin composition, and more specifically to a photosensitive resin composition for forming an interlayer insulation film that can be used in the production of multilayer printed wiring boards. do.

(Prior Art) In recent years, multilayer printed wiring boards in which wiring circuits are formed in multiple layers have been used in printed wiring boards for the purpose of increasing density.

Conventionally, multilayer printed wiring boards have been used in which multiple circuit boards on which inner layer circuits have been formed are laminated and pressed together using prepreg as an insulating layer, and then the inner layer circuits are connected through through holes. Ta.

However, in such a multilayer printed wiring board, since through holes passing through the wiring board are formed to connect desired inner layer circuits, each inner layer circuit becomes a complicated circuit that bypasses through holes that do not require connection. It has been difficult to increase the density of circuits.

Recently, as a multilayer printed wiring board capable of solving this difficulty, development of a multilayer printed wiring board in which conductor circuits and organic insulating layers are alternately built up has been actively progressed. This multilayer printed wiring board is suitable for ultra-high density, but it is difficult to form an organic insulating layer that can firmly adhere the plating film, so the conductor of this type of multilayer printed wiring board The circuit is formed using the PVD method or a combination of the PVD method and the plating method. However, forming conductor circuits by such a PVD method has the drawbacks of poor productivity and high cost. For this reason, the development of a photosensitive resin composition capable of forming an organic insulating layer to which a plating film can be firmly adhered has been awaited.

(Problems to be Solved by the Invention) The purpose of the present invention is to eliminate the drawbacks of the prior art, and to form an organic interlayer insulating layer that has excellent heat resistance and electrical insulation properties and can firmly adhere a plating film. The object of the present invention is to provide a photosensitive resin composition capable of

(Means for Solving the Problems) As a result of intensive research, the present inventor has developed a photosensitive resin composition based on (meth)acrylate of the epoxy resin shown in Formula 1, which has excellent properties in both heat resistance and flexibility. The insulating layer and the surface of the insulating layer are formed by constructing an insulating layer, containing a particulate filler that can be dissolved and removed by rough chemical conversion treatment, dissolving and removing the particulate filler by chemical conversion treatment on the surface of the insulating layer, and roughening the insulating layer surface. We succeeded in significantly improving the adhesion strength with the plating film formed thereon, and the above-mentioned problems were solved. That is,
The present invention provides (a) a compound represented by formula 1 (n is 0 or more)
a photopolymerizable compound in which at least one epoxy group is modified with (meth)acrylic, and
) a polymerizable compound having at least two or more terminal ethylene groups; (c) a photopolymerization initiator that generates radicals by actinic rays; (d) an epoxy curing agent; (e) a particulate filler; (f) ) A photosensitive resin composition containing a fine particle filler that can be dissolved and removed by chemical conversion treatment.

Formula 1 The photosensitive resin composition of the present invention is a photopolymerizable resin composition in which at least 1 gJi or more of epoxy groups are modified with (meth)acrylic, and at least one compound represented by formula 1 (n is 0 or more) is included as an essential component. Contains compounds. The epoxy resin represented by formula 1 used in the present invention is a combination of phenol aralkyl and epichlorohydrin obtained by condensing phenol and aralkyl ether (αα-dimethoxyvalaxylene) by Friedel-Crach reaction. It is produced by reacting in the presence of an alkali. Here, the number n is preferably 2 or more, and more preferably 4 or more. If the n number is less than 1, the tack will not be completely eliminated during drying, and when used as a photosensitive material, for example, when image exposure is performed by the contact method, it will adhere to the photomask film and it will be difficult to obtain a smooth surface. This is due to the fact that the resistance is low and the surface of the insulating layer may be eroded.

However, this problem can be solved by selecting the exposure method and development method, so the number n is not particularly limited.

Next, the epoxy resin represented by Formula 1 is subjected to (meth)acrylic modification using acrylic acids or methacrylic acids to obtain an essential component (hereinafter referred to as essential component (a)). Generally known acrylic acids or methacrylic acids can be used here, but acrylic acid is preferably used from the viewpoint of sensitivity and resolution. In the present invention, the degree of (meth)acrylic modification may be such that at least one epoxy group is (meth)acrylic modified, but preferably two or more epoxy groups are (meth)acrylic modified. It is preferable that
This is because when the number n is small and the degree of (meth)acrylic modification is small, the photocured film is likely to swell and peel off during development after image exposure.

The photosensitive resin composition of the present invention contains a polymerizable compound having at least two or more terminal ethylene groups (hereinafter referred to as essential component (b)) as an essential component. This compound is
Generally known materials can be used.

For example, dipentaerythritol hexaacrylate, 1
, 6-hexanediol diacrylate, Tris(2-
(7-cryloxyethyl) isocyanurate, neopentyl glycol diacrylate, diethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, diallyl terephthalate, N,N-methylenebisacrylamide, and the like. If the amount of the polymerizable compound as the essential component (b) is less than 1 part by weight per 100 parts by weight of the photopolymerizable compound as the essential component (a), the heat resistance of the cured film will decrease, and if the amount is 30 parts by weight or more. In this case, thermal shock resistance deteriorates. Therefore, the amount of the polymerizable compound used as the essential component (b) is 1 to 30 parts by weight, preferably 5 to 20 parts by weight, based on 100 parts by weight of the essential component (a).

The photosensitive resin composition of the present invention contains as an essential component a photopolymerization initiator (hereinafter referred to as essential component (c)) that generates radicals when exposed to actinic rays. As this photopolymerization initiator, a conventionally used photopolymerization initiator can be used. For example, benzophenone, 1-hydroxycyclohexylphenyl ketone, benzyl dialkyl ketal, 2-hydroxy-2-methylpropiophenone, Michler's ketone,
Examples include benzoin ethyl ether, 2,4-dialkylthioxanthone, 2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropanone, and the like. Furthermore, by combining the photopolymerization initiator with a sensitizer having a different absorption wavelength of actinic rays, the polymerization initiation efficiency can be improved and the sensitivity can be further increased. Examples include combinations of benzophenone and triethanolamine, 2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropanone and thioxanthone, and benzyl dialkyl ketal and Michler's ketone.

The amount of initiator, essential component (c), is equal to the amount of light 1 of essential component (a).
Total of polymerizable compounds and essential component (b)! i1
0.00 parts by weight. The amount is 1 to 20 parts by weight, preferably 1 to 15 parts by weight.

The photosensitive resin composition of the present invention contains 1 to 10 parts by weight of an epoxy curing agent as an essential component (hereinafter, essential component (d)
). Examples of the epoxy curing agent include imidazoles such as 1-methylimidazole, 1-phenylimidazole, and 1-benzyl-2-methylimidazole;
．． 3-bis(hydrazinocarboethyl)-5-isopropylhydantoin, boron trifluoride monoethylamine,
Examples include adipic acid, dihydrazide, dicyandiamide, and the like. However, from the viewpoint of electrical properties, it is preferable to use imidazoles or dicyanamide.

The photosensitive resin composition of the present invention contains a fine particle filler (hereinafter referred to as essential component (e)) as an essential component. Examples of fine particle fillers include silica, alumina, talc,
Examples include antimony dioxide, antimony pentoxide, aluminum hydroxide, calcium carbonate, and the like. The particle size of the particulate filler is preferably 0, 01-15 μm, more preferably 0-0 from the viewpoint of resolution, adhesion of the cured film, etc.
It is 1 to 2.5 μm. The amount of the particulate filler used as the essential component (e) is 10 to 60 parts by weight based on 100 parts by weight of the total amount of the essential component (a) and the essential component (b). It is desirable that the particulate filler is uniformly dispersed in the photosensitive resin composition, and for this purpose, the surface of the particulate filler can be treated with a coupling agent having a functional group such as an amino group or a hydroxyl group. . As a coupling agent, for example, γ
Examples thereof include -aminopropyltriethoxysilane, β-aminoethyl-γ-aminoprobyltriethoxysilane, and γ-methacryloxypropyltrimethoxysilane.

The photosensitive resin composition of the present invention has a fine particle filler (hereinafter referred to as an essential component) which can be dissolved and removed by chemical conversion treatment as an essential component.
f)). Particulate fillers that can be dissolved and removed by chemical conversion treatment include inorganic particulates such as silica and calcium carbonate, and heat-resistant resin particulates. However, here, it is desirable to use heat-resistant resin particles that have been pre-cured.The reason why it is desirable to use heat-resistant resin particles that have been cured in advance is that if heat-resistant resin particles that have not been cured in advance This is because when dispersed in the photosensitive resin composition, it dissolves in the resin liquid, making it impossible to selectively dissolve and remove it by chemical conversion treatment. If heat-resistant resin fine particles that have been cured in advance are used, they will not dissolve in the resin liquid even if they are dispersed in the photosensitive resin composition.
It is possible to form an insulating layer in which heat-resistant resin fine particles are uniformly dispersed. This insulating layer is subjected to chemical conversion treatment,
By dissolving and removing the heat-resistant resin particles, the surface of the insulating layer can be uniformly roughened, and a plating film can be reliably formed on the insulating layer.

The material of the heat-resistant resin fine particles is a resin that has excellent heat resistance and electrical properties, does not dissolve even when dispersed in a photosensitive resin composition by curing treatment, and has the property of being soluble in a specific chemical solution used for chemical conversion treatment. Any material may be used, and examples thereof include epoxy resins, polyester resins, bismaleimide-triazine resins, and the like. Methods for the curing treatment include a method of curing by heating and a method of curing by adding a catalyst. Further, as a specific chemical solution used for chemical conversion treatment, for example, an oxidizing agent such as chromic acid, chromate, permanganate, etc. can be used.

The particle size of the heat-resistant resin fine particles is preferably 15 lt m or less, more preferably 5 μm or less. The reason for this is that the roughened surface formed by dissolving and removing fine particles having a particle size of 15 μm or more becomes non-uniform, making it impossible to form a plating film with good reliability.

The amount of the particulate filler that can be dissolved and removed by the chemical conversion treatment of the essential component (f) is 10 to 60 parts by weight based on 100 parts by weight of the total amount of the essential component (a) and the essential component (b).

Furthermore, the photosensitive resin composition of the present invention may contain other subsidiary components. Examples of the subsidiary components include thermal polymerization inhibitors, pigments, color formers, coating improvers, antifoaming agents, adhesion improvers, leveling agents, and the like.

In addition, if necessary, bisphenol A type epoxy resin,
Various epoxy resins such as novolac type epoxy resin and cycloaliphatic epoxy resin can be used in combination.

The photosensitive resin composition of the present invention can be applied onto a substrate by a conventional method such as a dip coating method, a flow coating method, or a screen printing method. When coating, the Mi composition can be diluted with a solvent if necessary. Examples of the solvent include butyl cellosolve, methyl cellosolve acetate, butyl cellosolve acetate, methyl ethyl ketone, and cyclohexanone.

(Action of the invention) Although the photosensitive resin composition of the present invention has high heat resistance because the skeleton of the photopolymerizable compound constituting the main part is formed of an aromatic ring, the epoxy resin composition serving as a crosslinking point Since the group is present on every other aromatic ring, the crosslinking density is low and flexibility is high. This is particularly flexible compared to cresol novolac type epoxy resin, which is the backbone of the photopolymerizable compound that constitutes the main part of the photosensitive resin composition for forming a protective film used in the production of conventional printed wiring boards. Differences in gender become obvious.

Furthermore, the particulate filler contained in this photopolymerizable compound suppresses thermal expansion of the insulating layer and provides excellent adhesion to the underlying conductor.

Furthermore, since the photosensitive resin composition contains a particulate filler that can be dissolved and removed by chemical conversion treatment, by applying chemical conversion treatment to the cured film of the photosensitive resin composition, minute irregularities are formed on the surface of the cured film. . When plating is applied to such a surface, a plating film is formed even in the details of these minute irregularities.

If you try to peel off this plating film, the minute irregularities will get caught and act as what is called an anchor.

Furthermore, when this plating film is peeled off, the minute irregularities act as anchors, so the breaking strength of the cured film will control the peeling strength of the plating film. At this time, the cured product of the photopolymerizable compound that constitutes the main part of the photosensitive resin composition of the present invention has excellent flexibility compared to the cured product of ordinary cresol novolac type epoxy resin, etc. When the plating film is peeled off, the cured film is broken at a deeper position, and the adhesion strength is correspondingly higher.

In this way, the plating film formed on the cured film of the photosensitive resin composition of the present invention is firmly adhered, and the effects of the invention by the photosensitive resin composition of the present invention are produced.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these. Parts used as numerical units in the examples mean parts by weight. Further, the following equation 1 is expressed by the following equation.

Formula 1 % Formula % Phenol aralkyl type epoxy resin shown in Formula 1 (manufactured by Mitsui Toatsu Chemical Co., Ltd., prototype number: JE-325, n = 0
223 parts of epoxy equivalent, 36 parts of acrylic acid, 0.6 parts of benzyldimethylamine, and 0.06 parts of phenothiazine were dissolved in 170 parts of butyl cellosolve acetate with stirring, and air was added to the reaction system. The reactor was closed at 20:00 at 100 to 110°C while blowing. The acid value of the reactant was measured and the acid value was 0. The point where the score was 5 or less was taken as the end point.

Kai-1J (2 Phenolaralkyl type epoxy resin shown in formula 1 (manufactured by Mitsui Toatsu Chemical Co., Ltd., prototype number: XED-M.

n = 4 to 8, epoxy equivalent 260) 260 parts, 72 parts of acrylic acid, 1.3 parts of benzyldimethylamine, 0.13 parts of phenothiazine to 220 parts of butyl cellosolve acetate
1 part while stirring and dissolving 1 part, and blowing air into the reaction system.
The reaction was carried out at 00 to 110°C for 20 hours. The acid value of the reactant was measured and the acid value was 0. The point where the score was 5 or less was taken as the end point.

"Example E"-1), 100 parts of 50% acrylated phenol aralkyl epoxy resin synthesized according to Reference Example 1, 15 parts of diallyl terephthalate, 2-methyl-1-[4-(methylthio)phenyl]-2 -Morpholinopropanone-
1 (manufactured by Ciba Geigy, product name: Irgacure 90
7) 4 parts, imidazole (manufactured by Shikoku Kasei, trade name: 2 parts 4MH2), 4 parts of silica fine powder (manufactured by Nippon Shokubai Chemical Co., Ltd.,
Product name 2NS Silica x-05, average particle size 0.5μm)2
After mixing 25 parts of epoxy resin fine powder (manufactured by Toshi, trade name: Trepar EP-B, average particle size 0.5 μm), the viscosity was adjusted to 250 cps using a homodisper stirrer while adding butyl cellosolve, and then, Three parts were kneaded with a main roll to prepare a solution of the photosensitive resin composition.

2) Next, a solution of the photosensitive resin composition was applied using a knife coater onto the printed wiring board obtained by photoetching the surface of the copper-clad laminate using a conventional method, and the solution was left in a horizontal position for 20 minutes. , and was dried to the touch at 70° C. to form a photosensitive resin layer with a thickness of about 50 μm.

3) Next, a photomask film on which a black circle of 1100JJΦ was formed was attached closely to this, and it was heated with an ultra-high pressure mercury lamp for 55 minutes.
00 mj/cvl exposure. This was subjected to ultrasonic development treatment using a chlorocene solution to form 100 μmΦ pie-7 holes on the printed wiring board. Then,
This wiring board was heated to approximately 3000 mj/
c vn' exposure, then 1 hour at 100°C, then 1
By subjecting the film to a closed heat radiation treatment at 50° C. for 10 hours, a glabellar insulating film with excellent dimensional accuracy and having 7 pie holes corresponding to a photomask film was obtained.

4) Next, this interlayer insulation film was coated at a temperature of 70°C and a concentration of 5
The sample is roughened with 00 g/Q chromic acid for 15 minutes, immersed in a neutralizing solution (manufactured by Sibley, trade name: PM950), and washed with water. This coating contains fine silica particles that are insoluble in chromic acid and fine epoxy resin particles that are soluble in chromic acid, so by treating the surface of the coating with chromic acid, a roughened surface with a very complex shape was obtained.

5) Next, as a chemical plating pretreatment, a palladium catalyst (manufactured by Sibley, trade name: Catabosite 44) was applied to activate the surface, and a chemical steel plating solution with the following composition was applied with 15
After immersion for a minute, when 20 μm of copper was deposited in the pie 7 hole using an electrolytic copper plating solution having the following composition, the beer strength in normal state was 2.00 kg/cm. Also, M
IL-3TD-202Method 107Cond
In the thermal shock test according to ition B, 500
It has been revealed that the wire does not break even after cycling and has excellent long-term reliability. In addition, the diallyl terephthalate contained in the resin solution increases the crosslinking density during curing, so the cured film has excellent heat resistance.We conducted a solder heat resistance test at 260°C for 30 seconds, but no peeling or discoloration of the insulating layer film was observed. It wasn't done.

Chemical copper plating solution composition Sibley 328A 12.5%N
328L 12.5% //
328C1.5% pure water 73.5
% temperature
25°C electrolytic copper plating solution composition CuSO4.5) 120 150 g
/ QH2SO440g / Q CQ-20ppm Additive Specified low temperature
25°C cathode current density 2A/dm2 The photosensitive resin composition of this example has the following characteristics: the photopolymerizable compound used as an essential component has excellent heat resistance and flexibility, and chromic acid-insoluble silica Because it contains fine particles and chromic acid-soluble epoxy resin fine particles, the shape of the roughened surface is extremely complex, resulting in absolute RI.
When a conductor is formed on M, high adhesion can be obtained, and since the insulating film contains fine silica particles, the hardness of the hot part of the insulating film is high and thermal expansion is suppressed, so it has particularly excellent thermal shock resistance. It has characteristics such as:

K1L2 1), 60 parts of 100% acrylated phenol aralkyl epoxy resin synthesized according to Reference Example 2, 40 parts of bisphenol A epoxy resin (manufactured by Yuka Shell, trade name: Ebiko) 1001), diallyl terephthalate 1
5 parts, 4 parts of 2-hydroxy-2-2 methylpropiophenone (manufactured by Merck & Co., trade name: Darocure-1173),
30 parts of l,3-bis(hydrazi)carboethyl)-5-isobrovirhydontoin (manufactured by Ajinomoto Co., Ltd., trade name Niamicur VDH), fine talc powder (manufactured by Fuji Talc Industries, Ltd.)
Product name: LMS #200, average particle size 1.5 μm) 25 parts, epoxy resin fine powder (manufactured by Toshi, product name: Treval E
After mixing 35 parts of P-B (average particle size 0.5 μm), the viscosity was adjusted to 250 cps with a homodisper stirrer while adding butyl cellosolve, and then kneaded with three rolls to form a solution of the photosensitive resin composition. adjusted.

2) 5 Next, a solution of the photosensitive resin composition was applied using a knife coater onto the printed wiring board obtained by photoetching the surface of the copper-clad laminate using a conventional method, and after being left in a horizontal position for 20 minutes. , and was dried to the touch at 70° C. to form a photosensitive resin layer with a thickness of about 50 μm.

3) 8 Next, a photomask film on which a black circle of 100 μmΦ was formed was attached closely to this, and the film was heated with an ultra-high pressure mercury lamp at 40
0 mj/c-exposed. By applying ultrasonic development treatment to this with a chlorocene solution, it was printed onto a printed wiring board.
A via hole with a diameter of 00 μm was formed. Next, this wiring board was heated to approximately 3000 mj/cv using an ultra-high pressure mercury lamp.
n' exposure, roughly closed at 100℃ for 1 hour, then 150℃
By heat-treating for 10 hours, an interlayer insulating film with excellent dimensional accuracy and having via holes corresponding to a photomask film was obtained.

4) Next, this insulating film between the eyebrows was roughened with chromic acid according to the method of Example 1, a thin chemical copper plating was applied, and 20 μm of copper was deposited in the pipe hole by electric steel plating. Strength is 2.2Kg1cm
Met.

The photosensitive resin composition of this example uses Epicoat 1011) 1 as a bisphenol A epoxy resin in addition to the photopolymerizable compound used as an essential component, so it is more flexible than Example 1. is high, and when a conductor is formed on this insulating layer, high adhesion can be obtained.As an epoxy curing agent, l.

Because it uses 3-bis(hydrazinocarboethyl)-5-isobrobylhydontoin, the curing speed is fast, and final heating is sufficient with one o'clock closing, which significantly improves productivity, and because it contains diallyl terephthalate, curing is fast. The product has excellent heat resistance, and because it contains fine talc particles that are insoluble in chromic acid and fine epoxy particles that are soluble in chromic acid, the roughened surface forms a very complex unevenness, making it ideal for forming conductors. The feature is that high adhesion can be obtained when this is done.

(Effect of the invention) If the interlayer insulation film obtained using the photosensitive resin composition of the present invention is used, the adhesion between the conductor circuit made of the plating film and the insulation layer is extremely excellent, and the heat resistance and thermal shock resistance are improved. Excellent ultra-high-density multilayer wiring boards can be made.

In addition, the protective film obtained using the photosensitive resin composition of the present invention has excellent adhesion to the underlying conductor and can withstand high-temperature alkaline aqueous solutions, so it can permanently protect plating resists, solder masks, etc. It can also be used as a film and is extremely useful industrially.

that's all

Claims (1)

[Scope of Claims] A photosensitive resin composition comprising the following (a) to (f). (a) At least one compound represented by formula 1 (n is 0 or more) with at least one epoxy group (meth)
Acrylic modified photopolymerizable compound. Formula 1 ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (b) A polymerizable compound having at least two or more terminal ethylene groups. (c) A photopolymerization initiator that generates radicals when exposed to actinic rays. (d) Epoxy hardener. (e) Particulate filler. (f) Particulate filler that can be dissolved and removed by chemical conversion treatment.