JPH08248630A - Photo-via forming photosensitive element - Google Patents

Abstract

PURPOSE: To provide a photo-via forming photosensitive element which is excel lent in dielectric breakdown voltage, heat resistance, and flame resistance, and by which an insulating layer having a large adhesive strength between a conductor and an insulator can be formed. CONSTITUTION: In a photo-via forming photosensitive element in which a first layer of a photosensitive resin composition is formed on the surface of a light transmissive base material, and thereon a second layer of the photosensitive resin composition is formed; the first photosensitive resin composition as essential components is made up of (A) a resin composition consisting of 10 to 90 parts by weight of rubber and 10 to 90 parts by weight of epoxy resin, (B) an aromatic polyazido compound, (C) a thermosetting crosslinking agent, and (D) a filler, and the composition ratios by weight of (A) to (C), and (D) are (A) 100, (B) 1 to 10, (C) 1 to 80, and (D) 5 to 40; and the second photosensitive resin composition as essential components is made up of (1) a resin composition consisting of 20 to 80 parts by weight of bromine included film property providing polymer and 20 to 80 parts by weight of ethylene unsaturated monomer, and (2) a photopolymerization initiator, and the composition ratios by weight of (1) and (2) are (1) 100 and (2) 1 to 10 respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive element used for manufacturing a build-up method multilayer printed wiring board.

[0002]

2. Description of the Related Art In recent years, the density of printed wiring boards has increased, and the specific gravity of so-called multilayer wiring boards having a plurality of wiring layers has increased. Conventionally, in the manufacture of a multilayer printed wiring board, a method of press-forming a laminated board on which wiring has been formed via a plurality of thermosetting insulating sheets has been adopted, but there is a problem of alignment and a problem of shrinkage of a base material. Due to the above reasons, it is necessary to pay close attention to the production thereof, and therefore, it tends to be expensive. On the other hand, a so-called stacked type multilayer wiring board has been proposed in which an insulating layer is formed on a first wiring layer and a second wiring layer is formed thereon without taking the step of laminating press. .

For connecting the layers of the printed wiring board as described above, in addition to the conventional electrical connection between the layers by through holes, a non-penetrating connection method is performed by drilling. A new interlayer connection method such as post-plating is adopted. Further, in recent years, an excimer laser drilling method has been proposed as an alternative to this. Such an interlayer connection method is a non-penetrating method, and since the holes are arranged only in the portions where electrical connection between layers is required, the degree of freedom of wiring increases. Therefore, it greatly contributes to the reduction of the number of layers of the multilayer printed wiring board and the high density of the printed wiring board.

However, the conventional interlayer connection method basically forms holes sequentially, and the manufacturing cost increases as the number of holes increases. Multilayer printed wiring boards inevitably have many holes for interlayer connection, and even high-density products have more than 10,000 holes per sheet, and the drilling cost is the biggest factor that increases the cost of manufacturing multilayer printed wiring boards. Is one.

Recently, a so-called photo-via method has been proposed in which all connection holes are collectively formed by a photographic method.
The photo-via method is a method in which photolithography (exposure / development of a predetermined portion of a photosensitive resin layer, and etching or plating resist) which is mainly used when forming a conductor pattern is applied to an interlayer insulating film, Since it is a batch formation by the photographic method, the number of holes is irrelevant to the cost, and a via hole of small diameter, which is extremely difficult to form with a drill, can be precisely formed, and is therefore most promising as an interlayer connection method. For example, “Features and applications of surface wiring printed circuit boards (SLC)” (electronic materials, 199
April 1st issue, pp. 103-108), Japanese Patent Laid-Open No. 4-1485.
No. 90 discloses a multilayer wiring board in which photo vias are formed by using a photosensitive epoxy resin. Further, JP-A-4-180984 gives an example of an additive adhesive film containing an epoxy photoinitiator (however, since this example does not contain a photo-crosslinking agent for rubber, it is exposed to high-intensity ultraviolet light. However, good image formation cannot be performed).

As described above, the stacking type multilayer wiring board has advantages that it is possible to form a multilayer without a pressing step, and it is possible to form a small diameter via hole, and to form a fine wiring. However, when wiring is formed by the stacking method, it is inevitable to form a wiring pattern by forming a conductor on the interlayer insulating film by electroless plating. Further, the formed wiring pattern is required to have sufficient adhesiveness with the base material as represented by peel strength. Therefore, the insulating material as the interlayer insulating film required for this method is required to have image forming properties such as photo via holes, electroless plating resistance and plated copper adhesion.

The adhesive for electroless plating is conventionally known as an additive adhesive and is mainly composed of a rubber material. For example, JP-A-58-57776 and JP-A-62-248291 disclose examples in which the main components are epoxy resin, synthetic rubber and phenol resin, and JP-A-4-180984 discloses: A film adhesive containing an epoxy resin, a synthetic rubber, a phenolic resin, a chemical plating catalyst and a light-sensitive aromatic onium salt is disclosed. These examples are excellent in the roughening property by the roughening treatment liquid, and the adhesion of the plated copper is good.
A peel strength of more than 9.6 N / m is obtained. However, since these materials do not have photosensitivity, it is naturally impossible to form photovias.

On the other hand, as the heat-resistant resist material, many examples are known as a photosensitive solder mask material or a photoadditive material. These examples are photosensitive materials from the beginning, and although they have excellent image forming properties and electroless plating resistance, the adhesion of electroless plated copper is extremely poor. Further, it has a drawback that it is not sufficiently roughened even by a roughening treatment liquid, and although it has performance as a plating resist in an additive process, it is practically used as an additive adhesive (interlayer insulating film of photo via method). It cannot be used. In the example given above, roughening is possible with a special roughening liquid,
Although this roughening slightly improves the adhesion to the plated copper, the reported value is about 9.8 N / m, or less than this value, especially in the outermost layer portion. The adhesion is insufficient.

As described above, the insulating materials required for the stacking type multilayer wiring board include photovia forming property, heat resistance,
Precipitation of plated copper and adhesion of plated copper are required. A photosensitive element for forming a photo via that meets such a requirement is disclosed in Japanese Patent Laid-Open No. 6-148877.

This photosensitive element for forming a photo via is capable of forming an image on a translucent substrate by an actinic ray, and can form a fine shape on the surface by a roughening treatment liquid. A first photosensitive resin composition layer capable of depositing a conductor by means and a first photosensitive resin composition layer excellent in resistance to an electroless plating solution and excellent in insulation are laminated.

In this photosensitive element for forming a photo via, the first photosensitive resin layer provides an excellent roughened surface by the roughening treatment which is performed while forming an image, and imparts high adhesion to the plated copper. The second photosensitive resin layer forms an image, forms a photo via hole together with the first photosensitive resin layer, and has high electroless plating resistance and insulation properties,
It mainly contributes to the improvement of the insulation performance of the formed multilayer wiring board. Especially, by freely setting the film thickness, sufficient insulation between layers and improvement in electrolytic corrosion resistance are brought about. A filler is kneaded in the first photosensitive resin element in order to improve the roughening property, which impedes the transmission of actinic rays, and thus there is a limit to making the film thickness thick.

[0012] The second photosensitive resin layer provides an insulating property commensurate with the lack of the first photosensitive resin layer, and by laminating these two photosensitive resin layers, various problems mentioned above are solved. This enables the solved free multilayer board design. By adopting such a laminated structure, optimum properties can be imparted to each photosensitive resin layer, and it becomes possible to obtain a stack-type multilayer wiring board by the photo via hole method, which has been difficult in the past, in a simple process. .

[0013]

However, the photo-via forming element does not have the flame retardancy required for wiring board materials. An object of the present invention is to provide a photosensitive element for forming a photo via having high flame retardancy and high Tg.

[0014]

According to the present invention, a layer of a first photosensitive resin composition is formed on the surface of a translucent substrate, and a layer of the second photosensitive resin composition is formed thereon. In the formed photosensitive element for forming a photo via, the first photosensitive resin composition comprises (A) rubber 10 to 90 parts by weight and epoxy resin 1
A resin composition comprising 0 to 90 parts by weight, (B) an aromatic polyazide compound, (C) a thermosetting crosslinking agent and (D) a filler as essential components, and (A), (B), (C) and (D). The composition ratio of () is, by weight ratio, (A) 100, (B) 1 to 10,
(C) 1-80, (D) 5-40, and the second photosensitive resin composition is (1) bromine-containing film property imparting polymer 2
0-80 parts by weight and ethylenically unsaturated monomer 20-80
A resin composition consisting of parts by weight and (2) a photopolymerization initiator as essential components, and the composition ratio of (1) and (2) is a weight ratio,
(1) 100, (2) 1 to 10, which are photosensitive elements for photovia formation.

The first photosensitive resin composition layer is not necessarily required to have flame retardancy, but it is desirable to impart flame retardancy to this layer as well. Therefore, a part or all of the epoxy resin in the component (A) is a bromine-containing epoxy resin. It is desirable to blend the brominated epoxy resin so that the bromine content is 10 to 35% by weight based on the total epoxy resin.

The resin contained in the first photosensitive resin composition layer of the present invention is modified with a carboxylic acid-containing compound in order to improve the solubility when an aqueous developer is used.

As the rubber component, natural rubber, butadiene nitrile rubber, isoprene nitrile rubber, butadiene styrene rubber, acrylonitrile butadiene rubber, isoprene styrene rubber, a carboxylic acid-modified rubber obtained by adding a carboxylic acid-containing group to the main chain or side chain. Can be used.
Examples of such carboxylic acid-modified rubbers include polybutadiene (LPB) MAC-type, MM-type, and M-type manufactured by Nippon Petrochemical Co., Ltd., and carboxylic acid-modified NBR PNR-1H manufactured by Japan Synthetic Rubber Co., Ltd. And similar compounds thereof. The acid value of these carboxylic acid-modified rubbers is 20 to 130, more preferably 20 to 8
0. An image can be formed by dissolving these carboxylic acid-modified rubbers in an aqueous developer and using them with a photocurable crosslinking agent such as a bisazide compound. In addition to the carboxylic acid-modified rubber described above, an unmodified rubber may be used in combination. In this case, the adhesive strength of the plated copper can be increased by using a rubber having a property of effectively forming a fine shape in the roughening step. The compounding amount is 10 to 9 with respect to 100 parts by weight of the resin.
0 parts by weight, more preferably 20 to 50 parts by weight is suitable.

The epoxy resin component is a bisphenol type,
It is possible to use a carboxylic acid-modified epoxy resin of novolac type, cresol novolac type, alicyclic type or the like.

As the carvone modification method, there is a method of adding maleic anhydride or tetrahydrophthalic anhydride. In the photosensitive resin composition layer of the present invention, it is desirable that the bisphenol type low molecular weight substance is acid-modified for stability when mixed with another resin. Specifically, Ep1001, 1004, 10 manufactured by Yuka Shell
07, 1010, etc. are modified with maleic acid or tetrahydrophthalic acid. An image can be formed by dissolving these carboxylic acid-modified epoxy resins in an aqueous developer and using them together with bisazide. An image can be formed by dissolving these carboxylic acid-modified epoxy resins in an aqueous developing solution and using them in combination with bisazide. The acid value of these carboxylic acid-modified epoxy resins is 10 to 160, more preferably 10
~ 80. The compounding amount is 10 relative to 100 parts by weight of the resin.
To 90 parts by weight, more preferably 30 to 80 parts by weight.

The bromine-containing epoxy resin component added to impart flame retardancy to the first photosensitive resin composition may be the above carboxylic acid-modified epoxy resin with bromine introduced. The brominated epoxy resin may be modified with carboxylic acid. Specifically, Pratherm EP-100, EP-200 or EP-500, which is a brominated epoxy resin manufactured by Dainippon Ink and Chemicals, Inc.
In addition, maleic anhydride or tetrahydrophthalic anhydride added can be used.

In formulating the resin composition, the acid value of the entire resin composition is important. If the acid value is too low, the development with an aqueous developer becomes difficult, but if it is too high, the plating resistance and electrolytic corrosion resistance are deteriorated. The acid value of the photosensitive resin composition layer is 10 to 12
0 is desirable. Particularly, about 10 to 80 is preferable.

The aromatic polyazide compound is used as a cured film by photo-crosslinking the carboxylic acid-modified rubber, the carboxylic acid-modified epoxy resin and the carboxylic acid-modified Br group-containing epoxy resin in the photosensitive resin composition layer of the present invention. Among the aromatic polyazide compounds, aromatic bisazide compounds can be used. Aromatic bisazide compounds include, for example, 2,6-
Bis (4,4′-azidobenzal) cyclohexanone,
2,6-bis (4,4'-azidobenzal) methylcyclohexanone, 3,3'-diazidodiphenylsulfone, 4,4'-diazidostilbene, 4,4'-diazidochalcone, 3,3'-dimethoxy -4,4'-diazido biphenyl etc. are mentioned.

Thermosetting cross-linking agents include melamines, bismaleimides, hyanate esters and dicyandiamides. Among these, bismaleimides and cyanate esters are preferable in terms of heat resistance and progress of heat curing.
Dicyandiamides are also used in the present invention, like other epoxy resins. Bismaleimides include bis (p-maleimidylphenyl) methane and bis (m-
Maleimidylphenyl) methane, p, m′-bismaleimidylphenyl) methane, bis (p-maleimidylmethylphenyl) methane, bis (p-maleimidyldiethylphenyl) methane and the like. In addition, there are bismaleimides synthesized by using an aromatic diamine in which an aromatic group is linked by a sulfone group, a sulfone ether group, an ether group, and an ether-ketone group. Further, bismaleimides obtained by linking a plurality of aromatics to diphenylmethanes with a sulfone group, a sulfone ether group, an ether group, or an ether-ketone group are desirable because of improved solubility. Examples of such bismaleimide include 2,2-bis (p-maleimidylphenoxyphenyl) propane. Specifically, BBMI manufactured by Hitachi Chemical Co., Ltd. is used. Cyanate esters include triazine-type prepolymers which can be based on monomers such as bisphenol A dicyanate, tetramethylbisphenol A dicyanate, and hexafluorobisphenol A dicyanate.
Specifically, B-40S, M-40S manufactured by Ciba Kaiggy,
F-40S or the like is used.

Depending on the thermosetting cross-linking agent used, a thermal polymerization initiator is blended in a weight ratio of 0.1 to 10. In particular, when bismaleimides are used, it is necessary to use a thermal polymerization initiator depending on the thermosetting temperature. An organic peroxide can be used as the thermal polymerization initiator. The organic peroxide is selected in consideration of the thermosetting temperature and the storage conditions of the photosensitive element of the present invention, but one having a high decomposition temperature is preferable. Examples thereof include methyl ethyl ketone peroxide, dicumyl peroxide, 2,5-dimethyl-2,
5-di (t-butylperoxy) hexane, α, α′-
Bis (t-butylperoxy-m-isopropyl) benzene, t-butylcumyl peroxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, p-menthane hydroperoxide,
2,5-Dimethyl-2,5-di (t-butylperoxy) hexyne-3,1,1,3,3, -tetramethylbutyl hydroperoxide, 2,5-dimethylhexane-2,5-di For example, hydroperoxide. Specific examples of trade names are Perhexin 25B, Perkmill D, Perhexa 3M, Perhexa 25B, Permec N, Perbutyl O, Perbutyl Z, manufactured by NOF CORPORATION.
Etc.

The photosensitive element of the present invention has both photocurability and thermosetting property, and it is necessary to carry out post-photocuring and thermosetting after exposing and developing to form photo vias and the like. The thermosetting temperature and time depend on the properties of the compounds used for the thermosetting crosslinking agent and the thermal polymerization initiator. The temperature range is 100 ° C to 200 ° C, more preferably 100 ° C to 180 ° C.

It is preferable to add a filler to the first photosensitive resin layer of the present invention. The fillers are effective in imparting mechanical strength and heat resistance to the cured product and at the same time dissolving and dropping off by the roughening treatment liquid to impart a fine shape to the surface of the first photosensitive resin layer. Examples of the fillers include titanium oxide, calcium carbonate, magnesium carbonate, calcium silicate, zirconium silicate, magnesium oxide, calcium hydroxide, aluminum hydroxide, silica or talc. These fillers may be used alone or in combination.

If necessary, a plating catalyst is added to the first photosensitive resin layer. The plating catalyst serves as the core of electroless plating, and has a function of further increasing the adhesive strength of plated copper by premixing it in the element. As the plating catalyst used, P
In addition to compound particles of a metal such as d and a chloride thereof, particles obtained by adsorbing or mixing these with an inorganic substance or an organic substance can be used.

The second photosensitive resin layer is provided in order to improve the image forming property of the photosensitive element for forming a photo via and the electric insulating property between the layers. Therefore, it is possible to use various kinds of photosensitive resins for image formation which have been conventionally used without any special composition and characteristics. However, heat resistance and reliability are required because they are incorporated into the basic structure of a printed wiring board. From this viewpoint, a permanent resist composition is desirable.

The second photosensitive resin layer, together with the first photosensitive resin layer, must hold a stable film as a photosensitive element on the translucent substrate. Therefore, the second photosensitive resin contains a film property imparting polymer, and the compounding amount thereof is appropriately 20 to 80 parts by weight, preferably 30 to 70 parts by weight, based on 100 parts by weight of the resin.

The resin used in the second photosensitive resin layer is a polymer containing bromine and having a film forming property. Examples of the bromine-containing film property imparting polymer include bromine-introduced polystyrene, polyvinyl butyral, ethylene /
Vinyl acetate copolymer, polyvinylphenol, vinyl polymer such as styrene-maleic anhydride copolymer and / or its copolymer, polymethylmethacrylate, methylmethacrylate-methacrylic acid copolymer, methacrylic acid esters, acrylic acid Polymers or copolymers of esters,
Acrylic polymers such as copolymers of methacrylic acid esters and / or acrylic acid esters with methacrylic acid and / or acrylic acid, polycarbonates, phenoxy resins, novolac phenol resins, styrene-butadiene resins, styrene-isoprene resins, coumaro N-indene resin and the like can be mentioned. These bromine-containing film property imparting polymers may be modified with a carboxylic acid-containing compound in order to improve the solubility in an aqueous developer. As a carboxylic acid modification method, there is a method of adding maleic anhydride or tetrahydrophthalic anhydride. Specifically, it is a brominated epoxy resin manufactured by Dainippon Ink and Chemicals, Inc.,
Pratherm EP-100, EP-200 or EP-50
It is possible to use maleic anhydride or tetrahydrophthalic anhydride added to 0. These bromine-containing film property imparting polymers can be used alone or in combination. The type of the film property imparting polymer is not particularly limited, but it is selected from the viewpoint of heat resistance, electrical properties, image forming property, developability and the like of the cured product.

The ethylenically unsaturated monomer used in the second photosensitive resin gives a suitable flexibility to the photosensitive element as a plasticizer before curing and, after curing, forms a photosensitive resin layer together with the film property imparting polymer. It is necessary to provide various properties such as heat resistance and mechanical properties, and it is selected from this viewpoint. Above all,
Various acrylate monomers are preferable because they have good polymerizability. The acrylate monomer is various acrylic acid ester monomers, methacrylic acid ester monomers or a mixture thereof, and it is particularly preferable that various properties such as branch density, molecular weight and viscosity can be adjusted by selecting the matrix structure.

Examples of preferred ethylenically unsaturated monomers are A-TMPT, A-TMM3A-4G, A-9G,
A-14G, TMPT, 4G, 9G, 14G, BPE-
4, commercially available acrylate monomers such as BPE-10 or methacrylate monomers (all manufactured by Shin-Nakamura Chemical Co., Ltd.), viscoat # 540, viscoat # 700 (manufactured by Osaka Organic Industry Co., Ltd.), 1,6-hexanediacrylate, trimethyl. Hexane diisocyanate-hydroxyethyl acrylate adduct and the like can be mentioned. The blending amount of the ethylenically unsaturated monomer is 2 with respect to 100 parts by weight of the photosensitive resin.
It is 0 to 80 parts by weight, preferably 25 to 75 parts by weight.

The photopolymerization initiator used in the second photosensitive resin layer can be used without particular limitation as long as it can initiate the photopolymerization of the ethylenically unsaturated monomer. The type and blending part are determined in consideration of the extinction coefficient and absorption position of the photopolymerization initiator, but usually 0.1 to 10 parts by weight, more preferably 0.2 to 7 parts by weight with respect to 100 parts by weight of the resin. Parts by weight are used.

Examples of the photopolymerization initiator used are benzophenone, p, p'-diethylaminobenzophenone, benzoin isopropyl ether, benzyl, benzyl dimethyl acetal (trade name Irgacure 651;
Ciba Geigy), Irgacure 184, Irgacure 907 (all manufactured by Ciba Geigy), diethylthioxanthone, camphorquinone, p-dimethylaminochalcone, carbonylbis (diethylaminocoumarin) and the like.

The photopolymerization initiator may be combined with an auxiliary agent for promoting the initiation reaction. Examples of the auxiliary include triethanolamine, isoamyl diethylaminobenzoate, N-phenylglycine, N-methyl-N-phenylglycine and the like.

Other additives may be added to the photosensitive resin layer for various purposes. Examples of the additives include various polymerization inhibitors, antioxidants, dyes, pigments, flame retardants, thickeners, adhesion improvers, plating bath stabilizers, fluorescent agents and the like.

The photosensitive resin composition for forming a photo via is usually formed on a substrate material on which a circuit process is performed in advance on an insulating substrate. However, a simple insulating substrate or a substrate on which a conductor is entirely formed is used. It may be. At this time, known film forming methods such as bar coating, curtain coating, dip coating and spin coating are used. A uniform photosensitive adhesive film is formed by evaporating the bath agent by drying after coating.

The film thickness of the photosensitive adhesive film is determined mainly from the viewpoint of ensuring interlayer insulation reliability. If the photosensitive adhesive film is too thin, the dielectric strength will be insufficient. Further, an excessive film thickness increases the board thickness of the multilayer printed wiring board and reduces the resolution. From these viewpoints, the film thickness is 10 μm to 100 μm, preferably 15 μm to 70 μm. Among these, the film thickness of the first photosensitive resin vinegar is not particularly limited, but if it is too thin, the roughening property is insufficient,
If it is too thick, it adversely affects the resolution, so it is usually set to 5 μm to 50 μm, preferably 10 μm to 50 μm, and the rest is the film thickness of the second photosensitive resin layer.

The photosensitive element for forming a photo via is supplied together with a light-transmissive substrate having excellent dimensional stability such as a polyethylene terephthalate film. A protective film such as polyethylene is usually further laminated on this element. Thus, the photosensitive element for forming a via of the present invention has a structure in which a first photosensitive resin composition layer, a second photosensitive resin composition layer, and a protective film are laminated in this order on a light-transmitting substrate. ing. The protective film is removed from the photovia-forming photosensitive element prior to lamination. The first and second photosensitive resin composition layers may be formed by any of a method of applying a varnish and a method of laminating a film-shaped one.

The photo-via-forming photosensitive element is usually laminated on a substrate by a laminator equipped with a heating and pressing means. For this purpose, laminators equipped with a mechanism such as a hot roll, a substrate conveying system, a photosensitive element feeding out, and a pressure reduction are sold by each company, and can be used as they are without any special modification.

The light-transmitting base material of the photosensitive element for forming a photo via is formed by stacking the photosensitive element for forming a via via on the base material, and then performing exposure for forming a via hole before or after exposure. Is removed from the element.

When the translucent substrate is removed from the photosensitive element for forming the photo via, it is important to remove it with a weak force when the automation of the process is considered. For this purpose, it is desirable that the adhesive strength between the transparent substrate and the first photosensitive resin layer in direct contact with the transparent substrate is small.
In order to achieve this purpose, it is necessary to pay attention to the selection of the translucent base material.

The light-transmissive base material does not hinder the transmission of actinic rays necessary for image formation, and is resistant to heat and tension applied during the process of manufacturing the photosensitive element for photovia formation and the step of laminating it on the base material. It is selected from the viewpoint of having sufficient strength.

As examples of the translucent substrate, polyester films such as polyethylene terephthalate and polybutylene terephthalate, and polyolefin film materials such as oriented polypropylene and polystyrene are usually used. The film thickness is not particularly limited, but if it is too thin, the tension applied to the element at the time of manufacturing or stacking cannot be supported, and problems such as elongation and wrinkling of the base material occur. On the other hand, if the thickness is too large, the resolution will be lowered and the element will not penetrate into the substrate. Considering these things, usually 7μ
m to 100 μm, more preferably 10 μm to 30
It is selected in the μm range.

In order to reduce the peeling force of the translucent substrate,
It is extremely effective to preliminarily perform a peeling treatment on the side of the translucent substrate that contacts the photosensitive resin layer. At this time, various known materials such as a silicon material, a fluororesin material, and a paraffin material can be used as the release treatment agent. At this time, it is desirable to select a material from the viewpoint that the release treatment agent does not migrate to the photosensitive resin layer.

As the base material on which the photosensitive element for forming a photo via is laminated, the base material that has been conventionally used in the production of a printed wiring board is used as it is. Examples of the substrate include a glass epoxy laminate, a glass polyimide laminate, a paper epoxy laminate, a paper phenol laminate, a polyimide film and the like. It is usual that a conductor pattern is previously formed on these substrates by a known means.

A particularly preferable example of the base material on which the photosensitive element for forming a photo via is laminated is a base material formed by a so-called additive method. The additive method is a method in which an adhesive is coated on an insulating base material, an electroless plating resist is formed on the insulating base material, and then a conductor pattern such as copper is formed by electroless plating. This is because a substrate having high flatness, in which the heights of the plating resist and the conductor are substantially the same, can be obtained by controlling the above. In this method, the plating resist is not peeled off and can be used as it is as a permanent resist.

A particularly preferable second example of the base material on which the photosensitive element for forming a photo via is laminated is a printed wiring board formed by a transfer method. The transfer method is a method in which a circuit is formed by a plating method or the like on a removable temporary base material, the insulating base material is pressed to form a laminated plate, and then the temporary base material is removed. The base material produced by this method has a conductor pattern embedded in an insulating material to obtain a completely flat printed wiring board.

Lamination of the photosensitive element for photovia formation on these flat base materials is easy, and good adhesion to the base material and the conductor pattern is ensured by using a normally used normal pressure laminator. . It is possible to successively laminate both sides of the substrate at one time.

When such a flat base material is used, the photosensitive element for forming the photo via formed on the flat base material is also flat, so that, for example, the alignment accuracy of the mask is improved when the photo via is formed, and the uniform insulating layer is formed. Are advantageous in that the circuit design is simplified and the insulating layer can be thinned.

After formation of the photo via, a multilayer circuit is usually formed by an electroless plating method, and the flatness can be utilized also at this time. In general, the electroless plating method has a uniform plating metal deposition property, and plating that reflects the irregularities of the base material is possible. Therefore, the plated metal on a flat substrate is also flat.
As a result, more precise circuit formation is possible, and as the circuit formation method, means such as a tenting method can be used in addition to the plating method.

Although the use of flat substrates gives particularly favorable results, it is of course also possible to use the conventionally used non-planar substrates. In that case, a conductor pattern is formed on the surface of the base material, and a level difference corresponding to the presence of the conductor is present on the surface. In this case, it is useful to apply the photosensitive resin composition for photovia formation in the form of a solution as described above, and average the steps while forming the insulating layer. Lamination of photosensitive elements is also possible. In that case, it is necessary to pay particular attention to the biting of the photosensitive element for forming the photo via into the boundary portion between the insulating base material and the conductor. For this purpose, it is necessary to pay particular attention to the conditions such as laminating temperature, speed and pressure for laminating. The use of a laminator equipped with a pressure reducing means is desirable as a means for greatly relieving these points of concern.

As described above, the photosensitive resin composition for forming a photo via and the photosensitive adhesive film formed on the substrate by the photosensitive element using the same are subjected to a photosensitive adhesion by the exposure step and the subsequent development step. A via hole for interlayer connection is formed in a required portion of the agent film. The exposure is usually carried out through a mask, and only the necessary portions of the photosensitive adhesive film are exposed. At this time, the light-transmissive base material is coated on the photosensitive adhesive film formed by using the photosensitive element, but the light-transmissive base material may be directly coated at the time of exposure, or It may be removed from the photosensitive adhesive film prior to exposure.
As the exposure equipment, the equipment that has been conventionally used in the production of printed wiring boards can be used as it is.

If the light-transmitting base material remains after the exposure, the photosensitive adhesive film after exposure is removed, and then unnecessary portions in the photosensitive adhesive film are developed by a developer by development. Then, the photo via hole is formed. At this time, forming other signal wiring patterns other than the photo via holes is also included in the present invention. During development, means such as spray development and dip development are used.

As the developing solution, an alcoholic organic solvent,
An aqueous developer containing a mixed solution of a basic compound and water is preferable. A surfactant may be added in addition to the alcoholic organic solvent, the basic compound and water. As the alcohol organic solvent used for the aqueous developer, 2,2 ′-(butoxyethoxy) ethanol, 2-butoxyethanol and the like are preferable. The mixing ratio is preferably 10 to 50 g in 100 g of water. The basic compound may be organic or inorganic, and includes amines such as monoethanolamine and inorganic salts such as sodium tetraborate. Mixing ratio is water 100
In g, 0.5-10 g is desirable.

After the development, the processed photo via hole may be subjected to post-exposure, post-heating, etc. prior to the next step. By these treatments, the curing of the photosensitive adhesive film formed by the photo via hole is accelerated, and a preferable effect is obtained in terms of improving heat resistance.

As the post-exposure device, in addition to the exposure device used for image formation, a means such as a conveyor type exposure device is adopted.
In the post-exposure, it is desirable to increase the irradiation amount as compared with the exposure for forming the image to complete the photocuring.

When post-heating is carried out in order to further promote the curing reaction, it is desirable to carry out heating within a temperature range in which curing is promoted and the substrate and the like are not thermally deteriorated. As a heating means, a normal hot air oven furnace, an infrared furnace or the like, a conveyor heating furnace or the like is used, and the heating temperature is 80 ° C. to 180 ° C., more preferably 100 ° C. to 1
It is preferable to perform it in the range of 60 ° C. The time is selected from 5 minutes to 5 hours.

It is of course possible to omit either one or both of these post-exposure and post-heat treatments as long as the purpose of accelerating the curing is achieved, which contributes to the shortening of the steps. Also, the order is not particularly limited.

Particularly, it is preferable that the surface of the photosensitive adhesive film formed on the non-planar substrate is flattened by means such as polishing. The planarization improves the accuracy of the surface layer circuit processing that follows. As the polishing means, conventionally used polishing means such as buff roll, nylon brush, belt sander and the like are used.

When a through hole is required for a component insertion hole or an interlayer connection with another layer, a hole may be drilled. At this time, a normal NC drill machine is used. In the present invention, most of the signal connection between the multiple layers is achieved by the photo via holes, so that the drilling is performed to the minimum necessary, which greatly contributes to the shortening of the process. If necessary, the surface of the photosensitive adhesive film is roughened with a roughening treatment liquid after drilling. The purpose of roughening is to increase the adhesive strength of electroless plating by increasing the surface area of the surface of the photosensitive adhesive film. Various roughening treatment liquids are known for this purpose and are selected according to the purpose. As an example of the roughening treatment liquid, an acidic treatment liquid containing chromic anhydride / sulfuric acid as a main component and an alkaline treatment liquid such as potassium permanganate / sodium hydroxide liquid are known. It is more preferable to use a chromic acid-based treatment liquid for the roughening treatment of the present photosensitive adhesive, since it tends to give a better roughened surface.

Further, it is desirable to carry out the above-mentioned polishing before roughening with the treatment liquid. As a polishing method, baffle,
Nylon brush, belt sander, sandblast,
Honing and the like can be used.

The roughening treatment is carried out by immersing the base material on which the photo via holes have been obtained through the above-mentioned steps in the above-mentioned roughening treatment solution for an appropriate time. It is customary to heat the treatment liquid during immersion to accelerate the treatment. When a through hole or the like is formed in the base material, the side wall of the hole is also roughened by the roughening treatment. The temperature of the roughening treatment and the immersion time vary depending on the activity of the treatment liquid, but a bath temperature of room temperature to 80 ° C. for several minutes to several tens of minutes is generally suitable.
These conditions, along with the degree of roughening, should be carefully chosen because the conductor, which is usually copper, exposed to the base of the photosensitive adhesive tends to be attacked by these processing solutions.

As a solution to the case where the underlying conductor is attacked during the roughening, in addition to controlling the roughening conditions described above, a material resistant to the roughening treatment liquid is previously formed as a barrier layer. It is possible to set it. For example, a barrier layer for copper includes a nickel layer.

In this case, nickel may be thinly formed in advance on the conductor pattern arranged on the insulating substrate to which the photosensitive element for forming the photo via is laminated. Examples of the method for this purpose include a method of forming nickel thinly by a method such as an electroless nickel plating method.

As another means, it is possible to form the base material by the transfer method described above. In the transfer method, a barrier layer such as nickel is previously formed on the conductor serving as a carrier, a wiring pattern is formed by means of plating or the like through the nickel barrier layer, and then transferred onto an insulating base material, The carrier is removed to expose the wiring pattern. Therefore, the nickel barrier layer remains in advance on the wiring pattern of the base material manufactured by this method. Normally, this barrier layer is removed by etching, but if it remains until the end of the roughening step, it is possible to prevent erosion of the underlying conductor by the roughening treatment without adding a special step.

The film thickness of the barrier layer may be made thin by using an etching solution or a roughening solution having a large selection ratio, but it is important that there is no defect such as a bin hole. Although depending on the method for forming the barrier layer, it is usually 0.05 μm to 10 μm, preferably 0.1 μm to 5 μm.

By roughening the photosensitive adhesive film according to the present invention, it is possible to form a uniform fine shape. For example, when using a chromic acid / sulfuric acid-based roughening solution, 19.6 N / cm
The peel strength of 29.4 N / cm is actually measured.

After the roughening, a plating catalyst which serves as precipitation nuclei for electroless plating is supported on the surface. As a plating catalyst, various treatment liquids in which a metal colloid such as palladium is dispersed in various dispersion media are known, and by immersing the treatment liquid in a base material subjected to several pretreatments for cleaning. The loading of the plating catalyst is achieved. At this time, when the barrier layer is formed on the surface of the conductor, it is desirable to remove it by means such as etching in advance before carrying the catalyst, but if there is no problem in the connection between the layers, the removal step is omitted. It is also possible. When the plating catalyst is previously mixed in the photosensitive resin, the treatment for supporting the plating catalyst is not necessary.

After carrying the catalyst, electroless plating is carried out. At this time, the usual electroless plating conditions are applied as they are. The first method for forming the second conductor wiring is to form an electroless plating resist on a base material on which a catalyst is supported and perform electroless pattern plating. In this method, the electroless plating resist is formed in a pattern by means such as screen printing, the photosensitive liquid resist is formed by a coating means such as a curtain coater, and the electroless plating resist is formed by pattern formation by photolithography. Examples thereof include a forming method, a method of forming a pattern by laminating a photosensitive electroless plating resist film, and the like. As the latter method, a photosensitive solder mask film with various thicknesses, for example,
SR-3000, SR-3 manufactured by Hitachi Chemical Co., Ltd.
200 and the like are commercially available.

As a second method for forming the second conductor wiring, the electroless plating resist is not used, the electroless plating is thinly applied on the entire surface, and then the electrolytic plating is thickened to form the etching resist. The conductor pattern is formed by an etching method. In this method, the time required for plating is shortened and the electroless plating treatment time is short, so that the problems such as the penetration of the plating solution can be alleviated.

Before the electroless plating for forming the second conductor wiring as in the first and second methods, 0.
An uneven shape of 01 μm to 10 μm is transferred. That is, the photosensitive element for forming a photo via is exposed and developed to form a hole for interlayer connection, and the degree of curing of the insulating layer is appropriately increased by a treatment such as exposure and heating, if necessary, and then 0.01 μm to 10 μm. The base material having an uneven shape and the insulating layer are brought into close contact with each other, and the uneven shape is transferred by pressure bonding. Crimping is 0.0
It is carried out at any pressure between 98 and 98 MPa. It is preferable to heat in the range of 40 to 400 ° C. at the same time as the pressure bonding. The crimping conditions are selected in consideration of the characteristics of the insulating material used and in a range that does not destroy the shape of the formed holes.

Next, the substrate used for the transfer of the uneven shape is removed from the insulating layer after the pressure bonding process. This separation can be carried out mechanically if it is a flexible substrate, but in order not to destroy the uneven shape transferred to the insulating layer, it is preferable to use chemical means such as melting. preferable.
For example, when copper foil is used as the base material, the copper foil is removed by etching using an aqueous solution of ammonium persulfate or an ammonia complex-based copper etching solution.

There is no particular limitation on the substrate for transferring the uneven shape to the insulating layer. Although a foil or plate of plastic or metal can be used, a metal foil whose base material can be easily removed, such as a copper foil, an aluminum foil, or a nickel foil is preferable. As the copper foil, various copper foils can be used, but since the unevenness of the surface is fine, the surface of the electrolytic copper foil is rough, and after this surface is oxidized, it is reduced to give fine particles. Those having an uneven shape are preferable.

Further, the nickel surface of the two-layer copper foil in which a nickel layer having a thickness of about 1 μm to 2 μm is formed on the copper foil may be used as the shape transfer surface of fine irregularities. When a two-layer copper foil is used, after etching the copper foil, only nickel is etched by a nickel selective etching solution.

A plating catalyst is applied to the insulating layer to which the uneven shape is transferred (however, this step is not necessary when the insulating layer contains a plating catalyst), and electroless plating is used to remove copper, nickel, or the like. A conductor layer is formed. The thickness of the conductor layer needs to be about several μm to 100 μm. The formation of the conductor layer is
The whole may be electroless plated or electroplated together. A circuit pattern is formed on the obtained conductor layer by an ordinary photolithography process to form a second conductor wiring on the upper portion, and a multilayer printed wiring board is completed.

The third method for forming the second conductor wiring is
A method using a metal foil, for example, a copper foil. That is, a photosensitive element for forming a photo via is laminated on a wiring board on which a first conductor wiring is formed, and an interlayer connection hole (a hole reaching the first conductor wiring) is formed by pattern exposure and development.
Forming an insulating layer. After forming the holes, the degree of curing of the insulating layer may be appropriately increased by a treatment such as post-exposure or heating.

After that, a metal foil having an uneven shape of about 0.01 μm to 10 μm is brought into close contact with the insulating layer and pressure-bonded. The crimping is performed at any pressure between 0.098 and 98 MPa. It is preferable to heat in the range of 40 to 400 ° C. at the same time as the pressure bonding. The crimping conditions are selected in consideration of the characteristics of the insulating material used and in a range that does not destroy the shape of the formed holes.

Next, an etching resist is provided on the metal foil.
It is formed in the same position as the hole for interlayer connection formed in the photosensitive element for forming a photo via, which is an insulating layer.
That is, the etching resist is formed except for the portions where the copper foil is etched to form the land holes. The land hole preferably has a diameter equal to or larger than the diameter of the hole for interlayer connection of the insulating layer in consideration of the positional deviation. At this time, the land holes are aligned at the same positions as the interlayer connection holes of the insulating layer, so it is preferable to prepare a reference hole for alignment. The metal foil in the portion where the etching resist is not formed is etched to form the land hole, and an ammonium persulfate aqueous solution or an ammonia complex-based copper etching solution can be used for etching the metal foil.

The first conductor wiring and the metal foil are electrically connected by plating through the interlayer connecting holes of the insulating layer. The plating treatment may be performed after removing the etching resist, or may be performed without removing the etching resist and then removing the etching resist. When plating is performed without peeling off the etching resist, electroless plating is performed after etching of the metal foil in the hole for interlayer connection, and electroplating is used together with the first conductor wiring if necessary. Make a metal foil connection. After this, the etching resist is removed and the process proceeds to the next step.

When the etching resist is first peeled off and then the plating treatment is carried out, electroless plating is carried out after the etching of the metal foil in the hole for interlayer connection, and electroplating is also used if necessary. Make a connection between the first conductor wiring and the metal foil. In this case, since the plating is performed on the entire surface, it is conceivable that the plating on the metal foil is also performed along with the progress of the plating on the holes for interlayer connection, thereby increasing the thickness of the circuit to be formed later. Therefore, the thickness of the metal foil to be pressure-bonded is preferably thin, but in this case, a three-layer foil of copper / nickel / copper can be used from the viewpoint of mechanical strength and the like.

When a three-layer foil is used, a thin copper foil layer can be formed by performing selective etching of copper and selective etching of nickel after pressure bonding. As a copper etching treatment liquid, an ammonium persulfate aqueous solution, a polyvalent ammonia complex etching liquid, or the like can be used. As the nickel selective etching liquid, a melt strip liquid (manufactured by Meltex Co., nickel selective etching liquid) or the like can be used. After the connection plating treatment with the first conductor wiring, the second conductor wiring connected to the first conductor wiring is formed by a normal photolithography process or the like to form a multilayer structure.

As an example of the production of a photosensitive element for forming a photo via, first a photosensitive resin composition is coated on the transparent substrate, and then a second photosensitive resin composition is superposed thereon. To apply. For the purpose of improving workability, these photosensitive resin compositions are usually diluted with a solvent at the time of compounding or when used, and are usually used in the form of a solution having an appropriate viscosity. It is also possible to apply these. At this time, the solvent is selected from those having an appropriate solubility for the above materials. The solvent used for the first photosensitive resin composition may be different from that used for the second photosensitive resin composition.

Examples of the solvent used are methyl ethyl ketone, acetone, toluene, xylene, ethyl acetate,
Examples thereof include propyl acetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-ethoxyethyl acetate, dimethylformamide, cyclohexanone and the like.

The coating is carried out by a coating machine equipped with a translucent base material feeding means, coating means, drying means, protective film laminating means, winding means and the like. The photosensitive resin solution to be coated is evenly applied on the translucent substrate through the gaps such as doctor rolls, knives, nozzles, etc., and the solvent is removed by drying, and after laminating a protective film etc. as necessary. Roll up.

Various methods can be applied to the production of the photosensitive element for forming a photo via. For example, the first photosensitive resin layer may be first formed on the translucent substrate by the coating machine, and then the second photosensitive resin layer may be overlaid and coated thereon. Each step may be carried out in a batch process or continuously in a multi-stage coating machine. Further, the second photosensitive resin layer coated on another peelable substrate may be laminated.

As the second method, a liquid film is made to project or flow down from a large number of nozzles in a state in which a laminar flow state is assured to form a multi-layer liquid film, which is applied to a translucent base material at once. Is. According to this method, the number of steps required for coating is reduced,
It is possible to provide a photosensitive element for forming a photo via at low cost.

Since the photo-via-forming photosensitive element described above is formed by laminating different kinds of materials, there is a case where peeling occurs between the materials during development. As one of the causes of this, it is considered that the curing degree of each layer at the time of photo-curing is different. By adjusting the sensitivities of the respective materials to exposure to the same level, it becomes possible to suppress peeling at the lamination interface, improve the image forming form, and prevent film roughness during drying. The simplest method for adjusting the sensitivity of the first photosensitive resin is to adjust the amount of the aromatic polyazide compound in the first photosensitive resin composition, but rubber, phenol resin, epoxy resin, epoxy It is also possible to adjust by changing the compounding amounts of the resin curing agent, the fillers and the like. As a method for adjusting the sensitivity of the second photosensitive resin layer, it is convenient to adjust the amount of the photopolymerization initiator in the photosensitive resin composition, but the film property imparting polymer, the ethylenically unsaturated monomer It is also possible to adjust by changing the compounding amount. Furthermore, it is possible to adjust the sensitivity of each layer by changing the film thickness of the first photosensitive resin layer and the second photosensitive resin layer.

The sensitivity to exposure is evaluated by, for example, overlapping a photosensitive resin with a sensitivity mask (transmittance of 100 to 1% changed in 21 steps), exposing the photosensitive resin layer, and then developing the photosensitive resin layer. It is performed depending on which stage of the sensitivity mask the transmittance of which is exposed and the exposed portion is the boundary portion where the developer is dissolved or insoluble. That is, when two photosensitive resins are dissolved and insoluble at the time of development after exposure, when the boundary is a part exposed at the same stage (for example, stage 8) where the transmittance of the sensitivity mask is the same, This means that the two photosensitive resins have the same sensitivity to exposure.

In the case where the first photosensitive resin composition layer and the second photosensitive resin composition layer are laminated, peeling may occur at the interface between both layers at the time of development, so that the adhesiveness of both layers may be improved. It is desired to raise it. By containing at least one common component in both photosensitive resin layers, the adhesiveness at the interface can be improved and improved.

In the method for manufacturing a multilayer wiring board described above,
The wiring board on which the first conductor wiring is formed can be imaged by an actinic ray, a roughening treatment liquid can form a fine shape on the surface, and a conductor can be deposited. Laminate the film of the photosensitive resin composition of,
A film of the photosensitive resin composition is exposed and developed to form a hole reaching the first conductor wiring, and a second conductor wiring that is electrically connected to the first conductor wiring is formed on the film of the photosensitive resin composition. Characterize. By using a film-shaped photosensitive resin, it becomes possible to manufacture a multilayer wiring board using the photo via method with extremely high productivity.

Further, in such a method for manufacturing a multilayer board,
On the wiring board on which the first conductor wiring is formed, an insulating second photosensitive resin composition layer is formed, if necessary, and an image can be formed by actinic rays, and the surface can be formed by a roughening treatment liquid. To form a fine shape, and to form a first photosensitive resin composition layer capable of depositing a conductor,
It is characterized in that the photosensitive resin composition layer is exposed and developed to form a hole reaching the first conductor wiring, and a second conductor wiring which is electrically connected to the first conductor wiring is formed on the photosensitive resin composition layer. It is what This makes it possible to manufacture a highly reliable, high-density, high-precision multilayer dashed plate. These first and second photosensitive resin composition layers are preferably used by laminating film-like ones.

[0093]

【Example】

Synthesis Example 1 EP1004 (trade name of Yuka Shell Co., Ltd.) was dissolved in cyclohexanone so that the resin content was about 40%. The number of hydroxyl groups in the resin content was roughly calculated, and tetrahydrophthalic anhydride, which was 25% of the total equivalent of epoxy groups, was added, and the mixture was refluxed at 140 ° C. for 8 hours. The amount of solid components of the obtained tetrahydrophthalic acid-modified epoxy resin was 45.
%, And the acid value was 40.

Synthesis Example 2 EP100 (trade name of Dainippon Ink and Chemicals, Inc.)
Was dissolved in cyclohexanone so that the resin content was about 40%. Tetrahydrophthalic anhydride was added as in Synthesis Example 1, and the mixture was refluxed at 140 ° C. for 8 hours. The obtained tetrahydrophthalic acid-modified bromine-containing epoxy resin had a solid content of 45% and an acid value of 24.

Synthesis Example 3 EP200 (trade name of Dainippon Ink and Chemicals, Inc.)
Was dissolved in dimethylformamide so that the resin content was about 50%. Add tetrahydrophthalic anhydride 14
The mixture was refluxed at 0 ° C. for 8 hours to obtain a tetrahydrophthalic acid-modified bromine-containing epoxy resin having an acid value of 60.

Synthesis Example 4 Ep500 (trade name of Dainippon Ink and Chemicals, Inc.)
Was dissolved in dimethylformamide so that the resin content was about 50%. Add tetrahydrophthalic anhydride 14
The mixture was refluxed at 0 ° C. for 8 hours to obtain a tetrahydrophthalic acid-modified bromine-containing epoxy resin having an acid value of 48.

Example 1 40 parts by weight of the tetrahydrophthalic acid-modified epoxy resin synthesized in Synthesis Example 1, 10 parts by weight of the tetrahydrophthalic acid-modified bromine-containing epoxy resin synthesized in Synthesis Example 2, PNR-1H (carboxylic acid) was used as a rubber component. Modified NBR, trade name of Japan Synthetic Rubber Co., Ltd.) 20 parts by weight and XER-91 (methyl ethyl ketone dispersion cross-linked NBR, trade name of Japan Synthetic Rubber Co., Ltd.) 5 parts by weight, 3,3 'as bisazide component.
4 parts by weight of -dimethoxy-4,4'-diazidobiphenyl, BBMI (2,2-bis (p-maleimidylphenoxyphenyl) propane, as a bismaleimide component,
Hitachi Chemical Co., Ltd. product name) 20 parts by weight, as a polymerization initiator, Perhexin 25B (2,5-dimethyl-2,
2 parts by weight of 5-di (t-butylperoxy) hexine-3, trade name of NOF CORPORATION, 10 parts by weight of Hydilite H-42M as a filler, cyclohexanone 30
A mixture A was obtained by kneading 0 parts by weight.

25 parts by weight of tetrahydrophthalic acid-modified bromine-containing epoxy resin synthesized in Synthesis Example 3 and tetrahydrophthalic acid-modified bromine-containing epoxy resin 5 synthesized in Synthesis Example 4
0 parts by weight, BPE-4 (bisphenol A polyoxyethylene dimethacrylate, trade name of Shin Nakamura Chemical Co., Ltd.)
25 parts by weight, I-651 (benzyl dimethyl acetal, trade name of Ciba Geigy) 6 parts by weight, Victoria Pure Blue 0.04 parts by weight, methyl ethyl ketone 14
A mixture B was obtained by kneading 0 parts by weight.

Using the mixtures A and B, a roll film-like photovia-forming photosensitive element was produced using a trial coater having a doctor roll. P with a thickness of 20 μm
The mixture A was coated on an ET film GS (polyethylene terephthalate film, trade name of Teijin Ltd.) so that the film thickness of the drier was 28 μm, and wound. Next, the wound roll is moved to the feeding side, and the mixture B is applied thereon so that the total thickness of the photosensitive layer after coating and drying is 58 μm.
It was dried and wound while laminating a polyethylene film having a thickness of 30 μm to obtain a roll-shaped photovia-forming photosensitive element having a coating width of 330 mm.

The obtained photosensitive element for photovia formation was laminated on a substrate at 120 ° C. using a laminator manufactured by DuPont. As the substrate, a printed wiring board having an inner layer copper having a test pattern and a thickness of 18 μm was used.

On the laminated substrate, 500, 30
Image exposure was performed through a photomask having a via system of 0, 150, and 100 μm. HMW20 for the exposure machine
Using a type 1 exposure machine, under reduced pressure in a vacuum baking frame, 300
It was irradiated with ultraviolet rays of mJ / cm ² . The polyethylene terephthalate film was peeled off and developed for 10 minutes by a spray developing machine whose temperature was controlled at 45 ° C. The developer composition is 2,
An alkaline aqueous solution of 2 '-(butoxyethoxy) ethanol or a 100% organic solvent was used. 30 after washing with water at 60 ℃
After drying for a minute, using an electrodeless type ultraviolet irradiation device (Fusion Lamp AELIB / M manufactured by Somar Co., Ltd.),
Post-exposure was performed by irradiating with ³ J / cm ² of ultraviolet rays. Further dryer (SPH-200, manufactured by Tabeyes Tech Co., Ltd.)
Post heating was carried out at 170 ° C. for 30 minutes.

After the post-curing was completed, the surface was evenly sandblasted (Fuji Seiki Co., Ltd. HD-10) using Fuji White (Fuji Seiki Seisakusho Co., Ltd., alumina # 220). Then, the surface was roughened using a permanganate / sodium hydroxide-based roughening solution and treated with a hydrazine sulfate-based neutralizing solution. Using palladium chloride-based electroless copper plating catalyst, fine palladium particles serving as precipitation nuclei were supported on the surface, and Hitachi High-speed electroless plating bath L-59 (electroless plating bath, Hitachi Chemical Co., Ltd. product name) was used. The electroless plating was performed at 70 ° C. for 20 minutes, and then the entire surface was plated in a sulfuric acid-based bright electrolytic plating bath at room temperature for 1 hour at a current density of 2 A / dm ² .

It was confirmed that shiny copper plating was deposited almost uniformly over the entire surface to a thickness of about 35 μm, and an upper layer circuit was formed using a photomask having a test circuit pattern. Resist HN340-40 (a resist film, trade name of Hitachi Chemical Co., Ltd.) was laminated, exposed and developed to form a resist pattern, and copper was etched to form a circuit. Finally, the resist was peeled off with a 4% sodium hydroxide solution at 40 ° C. to obtain a photovia test pattern substrate.

Example 2 50 parts by weight of the tetrahydrophthalic acid-modified epoxy resin synthesized in Synthesis Example 1, and PNR-1H (carboxylic acid-modified NBR, trade name of Nippon Synthetic Rubber Co., Ltd.) 20 as a rubber component
Parts by weight and 5 parts by weight of XER-91 (methyl ethyl ketone dispersion crosslinked NBR, trade name of Nippon Synthetic Rubber Co., Ltd.), 3,3'-dimethoxy-4,4'-as bisazide component
4 parts by weight of diazidobiphenyl, 20 parts by weight of BBMI (2,2-bis (p-maleimidylphenoxyphenyl) propane, a product name of Hitachi Chemical Co., Ltd.) as a bismaleimide component, and Perhexin 25 as a polymerization initiator.
2 parts by weight of B (2,5-dimethyl-2,5-di (t-butylperoxy) hexin-3, trade name of NOF CORPORATION), 10 parts by weight of Hydilite H-42M as a filler, cyclohexanone 300 A part C was kneaded to obtain a mixture C.

60 parts by weight of a tetrahydrophthalic acid-modified bromine-containing epoxy resin synthesized in Synthesis Example 4, BPE-4 (bisphenol A polyoxyethylene dimethacrylate,
Shin Nakamura Chemical Co., Ltd. product name) 40 parts by weight, I-651
(Benzyl dimethyl acetal, trade name of Ciba-Geigy) 6 parts by weight, Victoria Pure Blue 0.04 parts by weight, and methyl ethyl ketone 140 parts by weight were kneaded to obtain a mixture D.

Using the mixtures C and D, a trial film coating machine having a doctor roll was used to prepare a photosensitive element for forming a photo-via for a roll film. P with a thickness of 20 μm
The mixture C was coated on an ET film GS (polyethylene terephthalate film, trade name of Teijin Ltd.) so that the film thickness of the drier was 28 μm, and wound. Next, the wound roll is moved to the feeding side, and the mixture D is applied thereon so that the thickness of the entire photosensitive layer after coating and drying is 58 μm,
It was dried and wound while laminating a polyethylene film having a thickness of 30 μm to obtain a roll-shaped photovia-forming photosensitive element having a coating width of 330 mm.

The obtained photosensitive element for photovia formation was laminated on a substrate at 120 ° C. by using a laminator manufactured by DuPont. As the substrate, a printed wiring board having an inner layer copper having a test pattern and a thickness of 18 μm was used.

On the laminated substrate, 500, 30
Image exposure was performed through a photomask having a via system of 0, 150, and 100 μm. HMW20 for the exposure machine
Using a type 1 exposure machine, under reduced pressure in a vacuum baking frame, 300
It was irradiated with ultraviolet rays of mJ / cm ² . The polyethylene terephthalate film was peeled off and developed for 180 seconds with a spray developing machine whose temperature was controlled at 35 ° C. The developer composition is 2,
It is an alkaline aqueous solution of 2 '-(butoxyethoxy) ethanol. After washing with water, it was dried at 60 ° C. for 30 minutes, and post-exposure was performed by irradiating ultraviolet rays of 3 J / cm ² using an electrodeless ultraviolet irradiator (manufactured by Somar Corporation, Fusion Lamp AELIB / M). Further, post-heating was performed at 170 ° C. for 30 minutes in a dryer (SPH-200 manufactured by Tabay Tech Co., Ltd.).

After the post-curing was completed, the surface was evenly sandblasted (Fuji Seiki Co., Ltd. HD-10) using Fuji White (Fuji Seiki Co., Ltd., alumina # 220). Then, the surface was roughened using a permanganate / sodium hydroxide-based roughening solution and treated with a hydrazine sulfate-based neutralizing solution. Using palladium chloride-based electroless copper plating catalyst, fine palladium particles serving as precipitation nuclei were supported on the surface, and Hitachi High-speed electroless plating bath L-59 (electroless plating bath, Hitachi Chemical Co., Ltd. product name) was used. The electroless plating was performed at 70 ° C. for 20 minutes, and then the entire surface was plated in a sulfuric acid-based bright electrolytic plating bath at room temperature for 1 hour at a current density of 2 A / dm ² .

It was confirmed that shiny copper plating was deposited almost uniformly over the entire surface to a thickness of about 35 μm, and an upper layer circuit was formed using a photomask having a test circuit pattern. Resist HN340-40 (a resist film, trade name of Hitachi Chemical Co., Ltd.) was laminated, exposed and developed to form a resist pattern, and copper was etched to form a circuit. Finally, the resist was peeled off with a 4% sodium hydroxide solution at 40 ° C. to obtain a photovia test pattern substrate.

Example 3 Using the mixture A (obtained in Example 1) and the mixture D (obtained in Example 2), a trial coater having a doctor roll was used to form a roll film photovia. A photosensitive element was prepared. The mixture A was applied onto a PET film GS (polyethylene terephthalate film, trade name of Teijin Limited) having a thickness of 20 μm, and the film thickness of the dryer was 28 μm.
It was coated so that Next, the wound roll is moved to the feeding side, and the mixture B is coated and dried so that the thickness of the entire photosensitive layer after coating and drying is 58 μm, and is wound while laminating a polyethylene film having a thickness of 30 μm. Then, a photosensitive element for forming a roll-shaped photovia having a coating width of 330 mm was obtained.

The obtained photosensitive element for photovia formation was laminated on a substrate at 120 ° C. by using a laminator manufactured by DuPont. As the substrate, a printed wiring board having an inner layer copper having a test pattern and a thickness of 18 μm was used.

On the laminated substrate, 500, 30
Image exposure was performed through a photomask having a via system of 0, 150, and 100 μm. HMW20 for the exposure machine
Using a type 1 exposure machine, under reduced pressure in a vacuum baking frame, 300
It was irradiated with ultraviolet rays of mJ / cm ² . The polyethylene terephthalate film was peeled off and developed for 180 seconds by a spray developing machine whose temperature was controlled at 40 ° C. The developer composition is 2,
It is an alkaline aqueous solution of 2 '-(butoxyethoxy) ethanol. After washing with water, it was dried at 60 ° C. for 30 minutes, and post-exposure was performed by irradiating ultraviolet rays of 3 J / cm ² using an electrodeless ultraviolet irradiator (manufactured by Somar Corporation, Fusion Lamp AELIB / M). Further, post-heating was performed at 170 ° C. for 30 minutes in a dryer (SPH-200 manufactured by Tabay Tech Co., Ltd.).

After completion of the post-curing, the surface was evenly sandblasted (Fuji Seiki Co., Ltd. HD-10) using Fuji White (Fuji Seiki Co., Ltd., alumina # 220). Then, the surface was roughened using a permanganate / sodium hydroxide-based roughening solution and treated with a hydrazine sulfate-based neutralizing solution. Using palladium chloride-based electroless copper plating catalyst, fine palladium particles serving as precipitation nuclei were supported on the surface, and Hitachi High-speed electroless plating bath L-59 (electroless plating bath, Hitachi Chemical Co., Ltd. product name) was used. The electroless plating was performed at 70 ° C. for 20 minutes, and then the entire surface was plated in a sulfuric acid-based bright electrolytic plating bath at room temperature for 1 hour at a current density of 2 A / dm ² .

It was confirmed that the glossy copper plating was deposited almost uniformly over the entire surface to a thickness of about 35 μm, and an upper circuit was formed using a photomask having a test circuit pattern. Resist HN340-40 (a resist film, trade name of Hitachi Chemical Co., Ltd.) was laminated, exposed and developed to form a resist pattern, and copper was etched to form a circuit. Finally, the resist was peeled off with a 4% sodium hydroxide solution at 40 ° C. to obtain a photovia test pattern substrate.

Example 4 The photosensitive element for forming a roll-shaped photovia obtained in Example 3 was laminated on MCL-E-67-1.6t (copper clad laminate, a product name of Hitachi Chemical Co., Ltd.). Image exposure (200 to 1000 mJ / cm ² ) was performed on this by the same manner as in Example 1 through a photomask having an image forming test pattern having various hole diameters of 1000 to 50 μm. Peel off the polyethylene terephthalate film, 4
Development was carried out for 1 to 7 minutes by a spray developing machine whose temperature was controlled at 0 ° C and 35 ° C, respectively. After rinsing with water, observe each sample and
The sample exposed at 0 mJ / cm ² was spray-developed for 5 minutes under the control of 25 ° C. As a result, it was found that 100% holes having a via diameter of 100 μm can be formed.

Example 5 The photosensitive element for forming a photo via obtained in Example 3 was laminated on a substrate on which copper of MCL-E-671.6t was etched to expose an epoxy surface, and copper foil. Then, the adhesive strength of the plated copper and the withstand voltage were examined. The sample laminated on the epoxy substrate is Example 1
Roughening, electroless plating, and electroplating were performed in the same manner as in (1) to prepare a sample for peel strength measurement. As a result, the copper peel strength was 0.6 × 10 ³ N / m, and the dielectric strength was 6.5 kV.
Met.

Example 6 The Tg of the photosensitive element for forming photovia used in Example 3 was measured. 120 by TMA penetration method
The value of 160 ° C was obtained by DVE.

Example 7 The photosensitive element for forming a photo via used in Example 3 was laminated on a substrate having a thickness of 1.2 mm in which copper was etched to expose an epoxy surface, and heat-cured.
Flame retardance was measured. As a result, the maximum burning time was 7 seconds and the average burning time was 3.5 seconds.

Comparative Example In the mixture A and the mixture D used in Example 3, a photosensitive element for forming a via, which was prepared by using a bromine-containing epoxy resin as a bromine-free epoxy resin, was used to etch copper to expose the epoxy surface. Thickness 1.2m
It was laminated on a substrate of m and subjected to thermosetting treatment, and flame retardancy was measured. As a result, a maximum burning time of 14 seconds and an average burning time of 7 seconds were obtained.

[0121]

EFFECT OF THE INVENTION A multilayer wiring board obtained by using the phobia forming element according to the present invention has excellent insulation breakdown voltage, heat resistance and flame retardancy, and has a high adhesive strength between a conductor and an insulator. Is.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location H05K 3/46 6921-4E H05K 3/46 T 6921-4EN (72) Inventor Takashi Yamadera Ibaraki Prefecture Shimodate City Ogawa 1500 Address Hitachi Chemical Co., Ltd. Shimodate Research Center

Claims (4)

[Claims] 1. A photosensitive element for forming a via, wherein a layer of a first photosensitive resin composition is formed on a surface of a light-transmitting substrate, and a layer of a second photosensitive resin composition is formed thereon. And the first photosensitive resin composition is (A) rubber 10 to 9
A resin composition comprising 0 parts by weight and 10 to 90 parts by weight of an epoxy resin, (B) an aromatic polyazide compound, (C) a thermosetting crosslinking agent and (D) a filler as essential components, and (A),
The composition ratio of (B), (C) and (D) is a weight ratio,
(A) 100, (B) 1-10, (C) 1-80,
(D) 5 to 40, wherein the second photosensitive resin composition is
(1) A resin composition comprising 20 to 80 parts by weight of a bromine-containing film property imparting polymer and 20 to 80 parts by weight of an ethylenically unsaturated monomer, and (2) a photopolymerization initiator as an essential component,
The composition ratio of (1) and (2) is (1) 10 by weight.
0, (2) 1 to 10, a photosensitive element for forming a photo via. 2. The epoxy resin has a bromine content of 10 to 35.
2. The photosensitive element for forming vias according to claim 1, wherein the photosensitive element contains a brominated epoxy resin so as to be contained in a weight percentage. 3. The photosensitive element for forming a photo via according to claim 1, wherein the (E) thermal polymerization initiator is added to the first photosensitive resin composition in a weight ratio of 0.1 to 10. 4. The rubber is a carboxylic acid-modified NBR, the epoxy resin is a tetrahydrophthalic acid-modified bisphenol A type epoxy resin, the aromatic polyazide compound is an aromatic bisazide compound, and the thermosetting crosslinking agent is a bismaleimide. 4. The photosensitive element for forming vias according to claim 3, wherein the thermal polymerization initiator is an organic peroxide, and the filler is one or both of aluminum hydroxide and silica.