JPH10204263A - Photosensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition useful as an insulating film for build-up of a multilayer circuit board, which can be patterned by ultraviolet exposure and development with an aqueous alkali solution after film formation, and a circuit board using the same. A method of making is provided. The composition comprises (a) an alkali-soluble particle component having an average particle size of 1 to 10 μm, (b) an epoxy compound, (c) an alkali-soluble epoxy curing agent,
(D) a compound having a radical polymerizable unsaturated bond; and (e) a photopolymerization initiator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive resin composition, and more particularly, it is useful as a build-up insulating film for a multilayer circuit board, which can be formed into a pattern by ultraviolet exposure and development with an aqueous alkali solution after film formation. The present invention relates to a photosensitive resin composition and a method for manufacturing a circuit board using the same.

[0002]

2. Description of the Related Art Conventionally, printed circuit boards have been generally used for compactly incorporating electronic components into electronic equipment. This printed circuit board etches the copper foil attached to the laminate according to the electronic circuit pattern,
Although it is difficult to mount electronic components at high density, it is advantageous in terms of cost. On the other hand, for hybrid ICs, a build-up multilayer wiring structure has been used for a long time. In this method, a thick film paste of a conductor and an insulator is sequentially printed on a ceramic substrate, stacked, and fired. This is disadvantageous in cost, but enables high-density mounting.

In recent years, along with demands for miniaturization, high performance, and low price of electronic equipment, the miniaturization of electronic circuits on printed circuit boards, multi-layering, and high-density mounting of electronic components have rapidly progressed. The study of build-up multilayer wiring structures for substrates has also become active. The build-up insulating film is formed between the layers of the electronic circuit, and is formed on the entire surface except for a portion to be connected to an upper electronic circuit (a portion generally called a “via hole”). Things.

FIG. 1 shows an example of a manufacturing process of a build-up structure. Specifically, first, a double-sided wiring board having a wiring pattern 2 and a through hole 3 filled with an insulating resin 4 is prepared as a core substrate 1 (FIG. 1A). Next, a photosensitive resin is coated on both sides of the core substrate 1, exposed and developed to form an insulating film 8 having a via hole 7 (FIG. 1B). Next, a conductor layer 11 is formed on the insulating film 8 by electroless plating / electrolytic plating (FIG. 1C), and this is etched to form a wiring pattern 12 (FIG. 1).
(D)). Thereafter, if necessary, the steps from the formation of the insulating film to the formation of the conductor pattern (the steps described with reference to FIGS. 1B to 1D) are repeated to produce a multilayer wiring structure.

As a photosensitive resin for forming the insulating film 8, for example, a photosensitive composition comprising a bisphenol-type epoxy acrylate, a sensitizer, an epoxy compound, a curing agent and the like (Japanese Patent Application Laid-Open No. 50-144431 and JP-B-51-40451) and the like can be used.
In addition, these photosensitive compositions use a large amount of an organic solvent during development, and thus have problems such as environmental pollution and fire risk. Composition is used. Examples of such an alkali-developable photosensitive resin composition include, for example, a photosensitive composition having a reaction product obtained by reacting an unsaturated monocarboxylic acid with an epoxy resin and further adding a polybasic acid anhydride as a base polymer. (Sho 56-40
329 and Japanese Patent Publication No. 57-45785). Further, an alkali developing type photosensitive composition using a novolak type epoxy resin and having excellent heat resistance and chemical resistance (JP-A-61-243869) can also be used.

[0006] In the build-up method, when a conductor is formed on a resin insulating film, the surface of the resin insulating film is roughened in order to improve the adhesion between the resin insulating film and the conductor, and then electroless plating is performed. Commonly used. In order to roughen the surface of a resin insulating film, a method of providing fine irregularities by chemical etching on a conductor forming surface of the insulating film is conventionally known.
Specifically, as shown in FIG. 2, a filler component 9 soluble by an acid or an oxidizing agent is added to the insulating film 8 (FIG. 2A), and the filler 9 is etched by an etching process.
Is dissolved to form an uneven portion 10 on the surface of the insulating film 8 (FIG. 2B). As the filler component, for example, calcium carbonate, barium sulfate, talc,
Clay or the like can be used. According to this method,
The metal to be plated as a conductor enters the uneven portion 10 formed on the surface of the insulating film, and the adhesion between the conductor and the resin insulating film is improved by the anchor effect.

[0007]

However, this chemical etching is usually performed under severe conditions using an acid or an oxidizing agent (generally, heating at a high temperature using permanganic acid). In addition, the resin insulating film is also etched, and it is difficult to provide an appropriate uneven portion. That is, even if the etching is insufficient or the etching is excessive, the adhesion of the conductor is reduced. Therefore, it is difficult to conveniently increase the adhesion when etching with an acid or an oxidizing agent. Furthermore, since the acid or oxidizing agent etching process requires many steps such as pretreatment and neutralization, if this process is included in the build-up structure manufacturing process, the number of steps increases and the cost is disadvantageous. It is. Further, usually used, fillers soluble by an acid or an oxidizing agent, for example, calcium carbonate, barium sulfate, talc, clay and the like are insoluble or hardly soluble in alkalis. The development remains (the filler remains in the formed via hole with a small amount of the insulating resin material). That is, if an excessive amount of filler is added in order to increase the adhesion, the undeveloped portion is increased and the resolution is reduced.

[0008] As described above, the conventional method of etching a filler contained in an insulating film with an acid or an oxidizing agent involves conductor adhesion, productivity, production cost, and resolution of a via hole formed by exposure and development. There is a problem in terms of gender. Therefore, the present invention solves such problems of the prior art, and a new alkali-developing photosensitive resin composition capable of advantageously forming a resin insulating film with improved conductor adhesion, and using the same. It is an object of the present invention to provide a circuit board manufacturing method.

[0009]

Means for Solving the Problems The photosensitive resin composition of the present invention comprises (a) an alkali-soluble resin having an average particle diameter of 1 to 10;
μm particle components, (b) an epoxy compound, (c) an alkali-soluble epoxy curing agent, (d) a compound having a radical polymerizable unsaturated bond, and (e) a photopolymerization initiator.

According to the method of manufacturing a circuit board of the present invention, a surface of a substrate is coated with a photosensitive resin material, exposed and developed to form an insulating film having openings of a predetermined pattern, and the surface of the insulating film is roughened. Forming a conductive layer on a roughened insulating film, and patterning the conductive layer to form a wiring layer, wherein the photosensitive resin material comprises: Having an average particle size of 1 to 10
a composition comprising a particle component of μm, (b) an epoxy compound, (c) an alkali-soluble epoxy curing agent, (d) a compound having a radical polymerizable unsaturated bond, and (e) a photopolymerization initiator, In addition, the surface of the insulating film is roughened by etching with an alkali treatment solution.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Briefly, the photosensitive resin composition of the present invention can be obtained by adding alkali-soluble fine particles as a filler to roughen the surface of the formed resin film by etching with an alkali treatment solution. An alkali-developable photosensitive resin composition capable of being carried out, having excellent conductor adhesion to an insulating film, excellent productivity, and excellent resolution of an opening (via hole) of a resin insulating film formed by exposure and development.
The composition is particularly useful as an insulating film for build-up of a circuit board.

The component (a) in the composition of the present invention, ie, the particle component, is alkali-soluble and has an average particle size of 1 to 1.
It is a particle component of 0 μm. Those particles exposed on the surface of the formed resin film are dissolved by alkali etching later to form fine irregularities on the surface of the resin film.
Therefore, the particle component is required to maintain the particle form in the composition, that is, to be insoluble or hardly soluble in other components constituting the composition.

A typical example of a suitable particle component in the composition of the present invention is phthalic acid. Phthalic acid is solid at room temperature and is readily soluble in aqueous alkaline solutions, such as dilute aqueous solutions of sodium carbonate, sodium hydroxide and the like. In addition, phthalic acid is insoluble or hardly soluble in other components constituting the composition of the present invention (details will be described later). Can be held. Also, when an organic solvent is used in the composition of the present invention, phthalic acid is insoluble or hardly soluble in general organic solvents, for example, ethylene glycol monoethers, acetates, cyclohexanone, toluene, xylene and the like.

The compound used as a particle component in the composition of the present invention is pulverized by a conventional pulverizer and then classified into particles having a desired particle size. In the present invention, the average particle size is preferably from 1 to 10 μm, more preferably from 3 to 6 μm. If the particle size is less than 1 μm, sufficient irregularities cannot be provided on the surface of the resin insulating film by etching with an alkali treatment, and the conductor adhesion becomes insufficient. Further, when the particle size is 10
If it exceeds μm, the irregularities become too large, and problems arise in the flatness and insulating properties of the resin insulating film and in the resolution of via holes formed by exposure and development.

The particle component is present in the composition of the present invention in an amount of from 10 to 5%.
Preferably it is present at 0% by weight. When the composition of the present invention contains a solvent, the above weight ratio of the particle component is based on the total weight of the components excluding the solvent (the above components (a) to (e)). Is equivalent to If the particle component is less than 10% by weight, the surface of the resin film is insufficiently roughened, and a satisfactory conductor adhesion cannot be obtained. If the content of the particle component exceeds 50% by weight, the irregularities on the surface of the resin film become too large, and the shape of the formed resin film is undesirably lost.

As the epoxy compound of the component (b), general compounds well known in the art can be used. For example, glycidyl ether type (bisphenol A type, tetraphenylolethane type, phenol novolak type, cresol novolak type, etc.), glycidyl ester type (hexahydrophthalic anhydride type, dimer acid type, etc.), glycidylamine type (diaminodiphenylmethane type, Epoxy compounds of isocyanuric acid type, hydantoin type, etc., mixed type (aminophenol type, oxybenzoic acid type, etc.) and alicyclic type can be used alone or in combination. When particularly high heat resistance is required, it is desirable to use an epoxy compound having a large number of functional groups.

The alkali-soluble epoxy curing agent of component (c) may be any of those known as epoxy curing agents as long as they are alkali-soluble. For example, a phenol compound, a cresol compound, or a compound having a carboxyl group can be used. Specific examples include novolak-type phenol resins, novolak-type cresol resins, and the like, and also include reaction products obtained by reacting an unsaturated monocarboxylic acid with an epoxy resin and further adding a polybasic anhydride. it can. Acid anhydrides, amines and the like may be used in combination. Specific examples include methylhexahydrophthalic anhydride, m-phenylenediamine, 4,4'-diaminodiphenylene sulfone, BF ₃
Monomethylamine, dicyandiamide, and the like can be used.

The compound having a radical polymerizable unsaturated bond of the component (d) is a photocurable component which is cured by exposure. The component (d) includes a vinyl group, an acrylic group,
Compounds having a methacryl group or the like can be used, and specific examples include styrene, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, glycerin dimethacrylate, ethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, and neopentyl. Glycol diacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, or the like can be used alone or as a mixture.

As the photopolymerization initiator of the component (e), those generally known as initiators for initiating photopolymerization of the compound having a radical polymerizable unsaturated bond of the component (d) may be used. it can. For example, Nikkei New Materials, April 16, 1990, p.43-49, Materials Technology, Vol. 2, No. 10 (1984), p. 1-17, Oplus E, No. 133,
p.105-116 (1990), Photopolymer Handbook, Photopolymer Society, edited by the Industrial Research Council, First Edition (1989), p.
Many initiators such as those described in 442-457 can be used.

Examples of usable photopolymerization initiators include:
3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, benzoyl peroxide, di (t
-Butylperoxy) phthalate, di (t-butylperoxy) terephthalate, di (t-butylperoxy)
Organic peroxides such as isophthalate. When these organic peroxides are used, 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran, 3,3'-carbonylbis is used as a sensitizer. (7-diethylaminocoumarin), 2,5-bis-
(4-Diethylaminobenzylidene) cyclopentanone, 2,6-bis- (4-dimethylaminobenzylidene) cyclohexanone and the like may be used.

Examples of other photopolymerization initiators include benzimidazole, 1-benzyl-2-methylimidazole, 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer, and 2- (o -Fluorophenyl) -4,5-diphenylimidazolyl dimer, 2-
Imidazoles such as (o-chlorophenyl) -4,5-bis- (m-methoxyphenyl) imidazolyl dimer and 2- (o-methoxyphenyl) -4,5-diphenylimidazolyl dimer; And 7-diethylamino-4-methylcoumarin, 2-mercaptobenzothiazole, 5-chloro-2-mercaptobenzothiazole, 2-mercaptobenzoxazole, p-aminobenzophenone, p-diethylaminobenzophenone, p, p'-bis (Ethylamino) benzophenone,
p, p'-bis (dimethylamino) benzophenone, 1
Examples thereof include a mixture of compounds selected from compounds such as H-1,2,4-triazole-3-thiol and 4-methyl-4H-1,2,4 triazole-3-thiol. When these are used as photopolymerization initiators, 3,3'-carbonylbis (7-diethylaminocoumarin), 2,6-bis-
(4-Dimethylaminobenzylidene) cyclohexanone, 2,5-bis- (4-diethylaminobenzylidene) cyclopentanone and the like can be used.

The composition of the present invention is generally applied to a processing substrate as a varnish. In order to obtain a varnish-like composition, the composition of the present invention may contain an appropriate solvent in addition to the above components (a) to (e). Examples of the solvent include organic solvents such as ethylene glycol monoethers, acetates, cyclohexanone, toluene, and xylene. Some of the component (d) of the composition of the present invention may be liquid, and when such a liquid component is used, it may not be necessary to use a solvent.

Further, a diluent may be added to the composition of the present invention for the purpose of improving coatability. As a diluent,
The same solvents as those described above, that is, organic solvents such as ethylene glycol monoethers, acetates, cyclohexanone, toluene, and xylene can be used. Further, for the purpose of accelerating the curing of the epoxy compound, an epoxy curing accelerator such as triphenylphosphine or 2-undecylimidazole may be added. In addition, if necessary, various additives, for example, an extender such as silica, alumina, and aerosil, a coloring pigment such as phthalocyanine, an antifoaming agent composed of silicone and a fluorine-based compound, a leveling agent, and an antioxidant may be added. Can be.

Used in the photosensitive resin composition of the present invention,
The amount of each component except the particle component of (a) is not important,
Those skilled in the art can easily determine the composition based on the specific required specifications of the composition and the like.

Next, a method for forming a build-up insulating film of a multilayer circuit board using the photosensitive resin composition of the present invention will be described below. The following description is intended to illustrate the method of the present invention and is not intended to be limiting.

First, the photosensitive resin composition of the present invention is applied to an electronic circuit board to a desired thickness by a method such as screen printing, curtain coating, roll coating or spin coating to form a film. Then, for the purpose of enabling contact exposure, an appropriate temperature, for example, 50 to 10
Heat at 0 ° C. to dry the film. Next, a portion to be connected to an upper electronic circuit to be formed thereafter (via hole portion)
A mask having a transparent portion except for is placed in contact with the film and irradiated with an appropriate amount of ultraviolet light. As a result, the compound having a radical polymerizable unsaturated bond of the component (d) undergoes photopolymerization under the action of the photopolymerization initiator of the component (e), and the photosensitive resin composition in the exposed region of the film becomes Except for the fine particle portion of the component, it becomes insoluble in an alkaline solution.

Subsequently, the non-exposed area is eluted and removed with a dilute alkaline aqueous solution, whereby the film is developed into a desired pattern. At the same time, the fine particles of the component (a) in the exposed area are eluted and removed, so that the resin insulation is removed. The film surface is etched, so that desired irregularities can be provided. Here, as the alkaline aqueous solution, a 0.1 to 10% by weight aqueous solution of sodium carbonate, an aqueous solution of sodium hydroxide, or the like can be used.

Next, the film is heated at an appropriate temperature, for example, 100 to 200 ° C., mainly for the purpose of improving the heat resistance of the film. As a result, the epoxy compound of the component (b) and the epoxy curing agent of the component (c) of the film remaining in the exposed region react with each other to form a final insulating film. Then
After performing electroless plating and electrolytic plating, a conductor layer is formed and patterned. Thereafter, the steps from application of the photosensitive resin composition to formation of the conductor pattern are repeated a predetermined number of times, whereby a multilayer circuit board can be manufactured.

In the method of the present invention, since the etching treatment is performed under milder conditions as compared with the conventional etching treatment using an acid or an oxidizing agent, appropriate irregularities are easily formed on the surface, and as a result, the conductor adhesion force is reduced. improves. Further, the step of etching with a conventional acid or oxidizing agent can be omitted, which is advantageous in terms of productivity and production cost. Further, since it is not necessary to use a commonly used filler which is soluble in an acid or an oxidizing agent and is insoluble in an alkali, for example, calcium carbonate, barium sulfate, talc, clay and the like, it is possible to obtain a high resolution by developing with an alkali developing agent. Does not decrease.

[0030]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, and the effect showing that the present invention is excellent will be described with the photosensitive resin composition lacking the requirements of the present invention. Shown in comparison. It goes without saying that the present invention is not limited to these examples.

[Examples] As the particle component, the average particle diameter was 5 μm.
Phthalic acid is used, and this is cresol novolak type epoxy resin (YDCN702 manufactured by Toto Kasei Co., Ltd.) and novolak type phenol resin (epoxy curing agent, manufactured by Gunei Chemical Co., Ltd.
SM-4300), pentaerythritol tetraacrylate (radical polymerizable compound), Irgacure 907
(Photopolymerization initiator manufactured by Ciba-Geigy) at a ratio shown in Table 1 and kneaded with a roll mill to prepare a photosensitive resin composition. To this composition, in addition to the above-mentioned components, triphenylphosphine as an epoxy curing accelerator, ethyloselosolve acetate as a diluent, and cyanine green as a coloring pigment were added. The amounts of the components used were as shown in Table 1.

The prepared composition was applied on a copper foil by screen printing to a thickness of 40 μm. Then, it is dried by heating at 80 ° C. for 1 hour, and the light intensity at a wavelength of 365 nm is 50 mW / cm ^2.
Was exposed in a predetermined via hole pattern for 30 seconds. Next, spray development (spray pressure 1 kg / cm ² , 60 seconds) with a 2% aqueous solution of sodium carbonate at a liquid temperature of 30 ° C. is performed to form a via hole, and at the same time the surface of the film is roughened. Was. The development resolution of the film thus obtained was evaluated. This development resolution is evaluated by inspecting the formed via hole with a microscope, and completely developing (the one in which neither the particle component nor other components remain in the via hole) is marked with ○, and the resin is included in the via hole together with the particle component. Were evaluated as Δ, and those with little via hole development were evaluated as x. The results obtained are as shown in Table 2.

Next, the adhesion (conductor peel strength) of the conductor film formed on the above film by electroless plating and electrolytic plating was evaluated. This evaluation is based on JIS C 648
The test was performed in accordance with the test method for copper-clad laminates for printed wiring boards specified in 1. Table 2 shows the obtained results.

Comparative Example A photosensitive resin composition was prepared in the same manner as in the example except that calcium carbonate (average particle size: 5 μm) was used as the particle component instead of the phthalic acid in the example. The amounts of the components used were as shown in Table 1.

Subsequently, the same treatment as in the example was carried out to obtain a cured resin film in which a via hole was formed. Then, this film was evaluated for development resolution as in the examples. Table 2 shows the results.

Next, the insulating film was treated with a pretreatment agent (conditioner made by Shipley, 60 ° C., 10 minutes), an oxidizing agent (promoter made by Shipley, 70 ° C., 10 minutes), a neutralizing agent (Nutizer, made by Shipley, 60 ° C., 10 minutes), and the surface was etched and roughened. Then, similarly to the examples, the adhesion of the conductor film formed on the film by performing electroless plating and electrolytic plating was evaluated. Table 2 shows the results.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

As is apparent from the above description, according to the present invention, it is possible to provide a resin insulating film which is more excellent in conductor adhesion, productivity and development resolution of an exposure pattern than conventional ones. Thus, it can greatly contribute to the formation of a build-up insulating film for a circuit board.

[Brief description of the drawings]

1A and 1B are diagrams illustrating a process for manufacturing a circuit board having a build-up structure, wherein FIG. 1A illustrates a step of preparing a core substrate, FIG. 1B illustrates a step of forming an insulating film having via holes,
(C) is a diagram showing a conductor layer forming process, and (d) is a diagram showing a conductor pattern forming process.

FIG. 2 is a diagram illustrating the roughening of the surface of a resin insulating film,
FIG. 2A is a diagram illustrating an insulating film formed of a material to which a filler component is added, and FIG. 2B is a diagram illustrating an insulating film having a roughened surface.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 core substrate 2 wiring pattern 3 through hole 4 insulating resin 7 insulating film 8 via hole 9 filler 10 uneven portion 11 conductive layer 12 wiring pattern

Claims (4)

[Claims] 1. An alkali-soluble particle component having an average particle size of 1 to 10 μm, (b) an epoxy compound,
A photosensitive resin composition comprising (c) an alkali-soluble epoxy curing agent, (d) a compound having a radical polymerizable unsaturated bond, and (e) a photopolymerization initiator. 2. The composition of claim 1, wherein said particulate component is phthalic acid. 3. A surface of a substrate is coated with a photosensitive resin material, and exposed and developed to form an insulating film having an opening of a predetermined pattern, and the surface of the insulating film is roughened. A method for producing a circuit board, comprising: forming a conductor layer on a substrate, and patterning the conductor layer to form a wiring layer, wherein the photosensitive resin material comprises: (a) an alkali-soluble, average particle size of 1; (B) an epoxy compound, (c) an alkali-soluble epoxy curing agent,
A composition comprising (d) a compound having a radical polymerizable unsaturated bond and (e) a photopolymerization initiator is used, and the surface of the insulating film is roughened by etching with an alkali treatment solution. Circuit board manufacturing method. 4. The method of claim 3, wherein said particulate component is phthalic acid.