JPH0312991A - Manufacturing method of electromagnetic shield wiring board - Google Patents

Abstract

PURPOSE:To prevent the generation of undercut phenomena of side walls of an insulation layer by piling two and over layers of optical hardening insulation materials which have different optical sensibility and/or development speed on a printed board so that the residual amount of the hardening layer after exposure and development may be decreased toward the surface, and then forming the insulation layer after exposure and development. CONSTITUTION:A combination of optical hardening insulation material layers 4a and 4b which exceeds two layers having different optical sensibility and/or development speed is applied on a printed board 1, which forms an insulation layer whose side walls expand upward. Therefore, when it is necessary to cover the insulation layer so as to form a conductivity layer, the insulation layer and the conductivity layer can be definitely formed thereon even when the printed substrate 1 is provided with a high density interconnection pattern 2, which makes it possible to prevent the generation of undercut of the side wall of the insulation layer or residual air foams.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel method for manufacturing an electromagnetic shielding wiring board.

[Traditional technique]

In recent years, electromagnetic noise (hereinafter simply referred to as noise) generated by various electronic devices such as office automation equipment (1) has been increasing.
The problem of noise is beginning to be considered important, and the demand for noise prevention measures is increasing.

As one means for preventing such noise, an electromagnetic shield wiring board has been proposed in which a conductive layer is formed on the surface of a printed wiring board that causes noise. The electromagnetic rolled wiring board described above requires an insulating layer between the printed wiring circuit patterns and the conductive layer to prevent short circuits between the patterns.

Conventionally, the insulating layer has been formed by screen printing an A8 curable or photocurable epoxy type insulating resist and curing the resist. However, as the pattern density of printed wiring boards has become more sophisticated, insulation with a higher M degree has been achieved by forming a layer made of an insulating photocuring material on the surface of the board, exposing and developing this layer. It has become clear that a means for forming layers is needed.

[What the present invention attempts to solve'1a, 1j11 Problem (2) However, in the method of locally developing a photocurable material, the twidwall of the insulating layer that is formed tends to be undercut, and then the conductive layer When laminating the conductive paste, it becomes difficult to fill the area with the conductive paste. Therefore, the conductive paste is cured with air bubbles remaining between the layer made of the photocurable material filled in the portion and the lower part of the sidewall of the insulating layer. As a result, pinholes are formed in the insulating layer, causing problems such as poor contact between the conductive layer and the ground pattern on the printed wiring board, which can lead to defective products. Means for Solving the Problem] As a result of intensive research in order to solve this problem, the present inventors have developed a method of forming layers of two or more types of photocurable materials with different photosensitivity and/or development speed on a printed wiring board. By forming the film so that the amount of the cured material remaining after development decreases toward the surface, the side wall of the formed insulating layer is prevented from undercutting, and air bubbles are not left in the area. The present invention was completed based on the discovery that a conductive layer can be formed without the formation of a conductive layer.

The present invention provides a method for producing an electromagnetic shield wiring board by sequentially laminating an insulating layer and a conductive layer on a printed wiring board. An electromagnetic shield wiring characterized in that layers of a curable insulating material are laminated such that the amount of the cured layer remaining after exposure and development decreases toward the surface, and then exposure and development are performed to form an insulating layer. This is a method of manufacturing a board.

In the present invention, a printed wiring board having a known structure can be used without particular limitation.

For example, a composite such as a glass epoxy composite, a paper-phenol resin composite, a plastic film, or a three-dimensional molded product such as a metal, a plate or a film is used as a support, and the additive method, subtractive method, die stamping method, etc. Generally, a conductive pattern is formed by a method such as a flash method. Such a printed wiring board is
Those having a wiring pattern on one side or both sides, and those having a meandering multilayer wiring pattern structure can be used without particular limitation.

In the printed wiring board, circuits that require electromagnetic shielding are particularly circuit wiring that transmits high-frequency current such as digital signals, or circuit wiring that is susceptible to external high-frequency noise. In the present invention, 1i! by forming a conductive layer! Magnetic shielding measures can be taken not only by applying countermeasures to the circuit wiring that requires electromagnetic shielding, which is dispersed as in the past, but also by concentrating the circuits that require countermeasures on one side using CAD etc. This includes cases in which electromagnetic shielding is carried out economically and effectively by means of countermeasures.

In the present invention, the photocurable insulating material is not limited to glaze, as long as it is hardened by active light such as visible light, ultraviolet rays, and X-rays, and the cured material has insulating properties. Generally, (a) a polymerizable unsaturated compound, (
b) A photopolymerization initiator and a polymeric binder are used.

As the above-mentioned polymerizable unsaturated compound, any known compound capable of radical polymerization may be used without particular limitation. Examples of suitable polymerizable unsaturated compounds include epoxy group-containing compounds obtained by addition-reacting triglycidyl isocyanurate and unsaturated group-containing monocarboxylic acids at an acid equivalent/epoxy equivalent ratio of 0.3 to 09. An esterified resin obtained by reacting an unsaturated compound, an epoxy group/container of a novolac type epoxy resin, with 0.8 to 1.3 equivalents of ethylenically unsaturated carboxylic acid;
At least one novolac type epoxy resin selected from the group consisting of orthocresol novolac type epoxy resin, phenol novolac type Evoquin resin, and halogenated phenol novolac type epoxy resin and an unsaturated carboxylic acid at an acid equivalent/epoxy equivalent ratio is 01~09(6
) An unsaturated compound obtained by reacting the secondary hydroxyl group of an unsaturated compound obtained by an addition reaction in the range of incyanato ethyl methacrylate with an inanate/hydroxyl group ratio in the range of 01 to 2, 1 of this epoxy resin to an epoxy resin having at least two terminal epoxy groups.
07 to 15 moles of ethylene bonds per epoxy equivalent
Containing an unsaturated group derived from an epoxy resin such as an unsaturated compound obtained by reacting the unsaturated carboxylic acid contained therein and then further reacting with 02 to 1 mole of polyhydric acid anhydride per I epoxy equivalent. Epoxy resins and trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, tetramethylolmethane triacrylate, tetramethylolmethane trimethacrylate, tetramethylolmethane trimethacrylate, tetramethylolpropane Polyfunctional monomers such as tetraacrylate, tetramethylolpropane tetramethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, diventaerythritol benquaacrylate, dipentaerythritol pentamethacrylate, 1.111-)(acryloxypropoxymethyl)propane Can be mentioned.

Furthermore, there are no particular restrictions on the photopolymerization initiator. For example, benzophenones such as benzophenone, 4.4 dimethylaminobenzophenone, 4.4'-diethylaminobenzophenone, 2-ethylanthraquinone, tθ
Anthraquinones such as rt-butyl anthraquinone, benzoyl alkyl ethers of benzoin ethyl ether, benzoin propyl ether nato, 2.2-dimethoxy-2-phenylacetophenone, 2+ 2-shed beef diacetophenone, 2-chlorothioxanthone,
Diethylthioxanthone, 2-hydroxy-2-methylpropiophenone, 4'-isopropyl-2-hydroquine-2-methylpropiophenone, 2-methyl-1-(
4-(methylthio)-phenyl2-morpholino=
Examples include 1-glopanone, which may be used alone or in combination of two or more.

Further, as the polymer binder, any known polymer binder soluble in an alkaline aqueous solution or an organic solvent can be used without particular limitation. Among these, polymers that are soluble in aqueous alkaline solutions and insoluble in water, for example, polymers having alkali solubility-imparting groups such as carboxyl groups, carboxylic anhydride groups, sulfonic acid groups, and sulfonamide groups, are preferred. used. These polymeric binders are disclosed, for example, in JP-A-59-151152, JP-A-58-42040, and JP-A-4873.
It is described in Publication No. 148, etc. Generally, a copolymer of a carboxylic acid or an acid anhydride and a vinyl monomer having one unsaturated group selected from the group consisting of methacrylic acid, acrylic acid, itaconic acid, crotonic acid, and maleic anhydride. is used.

Among them, specific examples of particularly preferred polymeric binders include methyl methacrylate/ethyl acrylate/methacrylic acid copolymer, methyl methacrylate/ethyl acrylate/acrylic acid copolymer, methyl methacrylate/butyl methacrylate/ Examples include 2-hydroxyethyl acrylate/butyl methacrylate/methacrylic acid copolymer, methyl methacrylate/tribromophenyl acrylate/methacrylic acid copolymer, and the like. Moreover, it is preferable that these polymeric binders have a carboxyl group content of 10 to 50 mol%.

The above-mentioned photocurable insulating materials can be used as filling materials,
Polymerization inhibitors, dyes, pigments, solvents, etc. may be added.

In the present invention, the layer made of the above-mentioned photocurable insulating material on the printed wiring board is formed by exposing at least two types of layers having different sensitivities and/or development speeds to light (10), and the remaining amount of the cured layer after development. It is formed by laminating layers such that the amount decreases toward the surface.

In the present invention, the difference in photosensitivity between layers of laminated photocurable insulation materials was measured by the gray scale method (hereinafter simply referred to as the gray scale method) using a Stouffer 40 step tablet. refers to value.

Quantification of photosensitivity by the power-karu gray school method is carried out in accordance with the method described in Gentabe Nagamatsu and Hideo Inui, "Photosensitive Polymer", p. 50 (Kodansha). That is, a dry photocurable insulating material was placed on a commercially available copper-clad laminate to a thickness of 25 mm.
A sample coated with a doctor blade so as to have a thickness of μm is used as an evaluation sample. As for the grayscale used in Kenpo, use the Stouffer 4 O&Step tablet. After exposure through this step tablet and development at a break point of 50%, the number of steps (sensitivity) corresponding to the step tablet is determined from the cured material remaining on the copper clad laminate.
Read. For example, if the cured product remains up to the 25th stage of the step tablet and is washed away by development at the 26th stage, the sensitivity of the photocurable insulation material of this sample is read as 25th stage. 'th, using a laminated photocurable insulating material, first, using one of the samples, adjust the exposure amount so as to obtain a sensitivity of 15 to 25 steps by the above procedure, and then Using the same exposure and development conditions, the sensitivity of other photocurable insulating materials laminated thereon is also measured under the same conditions.

1. The development speed of the photocurable insulating material is a value measured by the following method.

That is, using a developer suitable for photocurable insulating materials, such as a 1% Na 2 Co 3 aqueous solution in the case of water-soluble photocurable insulating materials, and using a spray developing machine with a cone-type nozzle, the surface of the substrate is visually inspected. Apply unexposed photocurable insulating material to f& to such an extent that the remaining photocurable insulating material can be confirmed.
The coated substrate was placed on an area of 25 cm x 25 cm with a thickness of 11 m, and a developer at a temperature of 30°C was sprayed at a pressure of 1
Develop in 4 steps. At this time, if t (seconds) is the time taken until the photocurable insulating material is washed away from the substrate surface, then t (seconds) is the development time (break point 100%).

Incidentally, the development time required for sensitivity measurement is 2t (seconds) under the same development conditions. (Breakpoint 50%).

This 2t (seconds) is often adopted as the optimum development time for photocurable insulating materials. The difference in development speed between the layers is the ratio (tl/12) of the development time (tl) of the layer on the surface side to the development time (t2) of the layer on the printed wiring board side.
Represented by

When using a solid dry film as a photocurable insulating material, the sensitivity and development speed of the dry film can be measured by first dissolving the resist portion in a suitable solvent (13) and then using the same method as for liquid resist. evaluate.

In the present invention, in order to reduce the residual amount of the cured layer toward the surface due to the difference in photosensitivity between layers made of photocurable insulating materials, the difference in the number of stages (X ) is 1 to 15, preferably 3 to 9, and the layers may be stacked so that the number of steps decreases toward the surface. If the difference in the number of steps is less than 1, it will be difficult to reduce the remaining lid of the cured layer toward the surface when the layer made of photocurable insulating material is exposed and developed, and the difference in the number of steps will be less than 1. When it is larger than 15, the degree of development of the core layer decreases, making it difficult to form a high-density pattern. In addition, in this case, the difference in development speed of the layer r river is t 1
/ t 2 is preferably in the range of 0.1 to 10.5 In addition, due to the difference in development speed between layers made of photocurable insulating material, the amount of remaining cured layer can be reduced by self-cutting on the surface. In order to achieve this, the development speed of each layer should be adjusted so that the tl/t2 ratio described in (14) above is 01 to 1, preferably 0.5 to 0.8. If the ratio of the above development speeds is smaller than 01,
When a layer made of a photocurable insulating material is exposed and developed, it becomes difficult to reduce the remaining amount of the cured layer toward the surface, and when the ratio of development speeds is 1 or more, the core layer decreases. The degree of development decreases, making it difficult to form a high-density pattern. In this case, it is preferable that the difference (X) in the number of steps indicating the above-mentioned sensitivity between the layers is set to -10 to 15.

Of course, both the difference in photosensitivity and the difference in development speed between the layers of the photocurable insulating material can be compensated for by adjusting the photosensitivity and development speed of each layer so that the amount of remaining cured layer after exposure and development of the core layer decreases toward the surface. It is also possible to adjust the development speed.

The photosensitivity or development speed of the photocurable insulating material described above can be adjusted by changing the composition ratio of the monomerically unsaturated compound, the photopolymerization initiator, and the polymeric binder, the type of each (15) component, etc. It can be carried out. That is, the photosensitivity can be changed by changing the blending ratio of the photopolymerization initiator, and the development speed can also be changed to some extent by the chemical structure of the 11-polymerized unsaturated compound. It can be adjusted by changing the carboxyl group content of the polymeric binder. Additionally, it may vary depending on the molecular weight of the polymeric binder and the hydrophilicity of the comonomer.

Generally, the composition ratio of each component is such that the polymer binder is in the range of 50 to 30 parts by weight, preferably 100 to 200 parts by weight, per 100 parts by weight of the monounsaturated compound, and The polymerization initiator is used in an amount of 01 to 20%, preferably 3%, based on the total amount of the polymerizable unsaturated compound and the polymeric binder.
It is preferable to determine it within the range of 101% by weight.

In the present invention, the method of laminating photocurable insulating materials is not particularly limited as long as the preconditions are satisfied. For example, the photocurable (I6) insulating material can be laminated on a printed wiring board in the form of a solid film generally referred to as a dry film, or in a liquid state. That is, solid film sheets or liquid photocurable insulating materials with different photosensitivity and/or development speed may be laminated together, or liquid photocurable insulating materials with different photosensitivity and/or development speed may be laminated together. and a photocurable insulating material in the form of a solid film may be laminated. As a method for forming a layer using a liquid photocurable insulating material, any known means such as a dip coating method, a blow coating method, a screen printing method, etc. may be employed without particular limitation. Moreover, after drying the solvent contained in the above layer, other layers may be laminated or exposed.

Among the above lamination methods, it is preferable to use a liquid photocurable insulating material as the layer in contact with the printed wiring board. In other words, by using a liquid photocurable insulating material, there are no irregularities, through holes, etc. on the printed wiring board (
17) Adhesion can be further improved when

Further, even if a small through hole exists, the liquid photocurable insulating material can be reliably penetrated into the through hole by irradiating it with ultrasonic waves. force)
The photocurable insulating material in the form of a filtrate may be prepared from among the compositions of the 41 photocurable insulation materials, or may be prepared by dissolving the photocurable insulating material in a solvent. . Examples of such solvents include methyl ethyl ketone, methyl cellosolve acetate, ethyl seron rub acetate, cyclohexanone, methyl cellosolve, pyrene glycol methyl ether acetate,
Methylene chloride, propylene glycol monomethyl ether, etc. can be used.

The thickness of the layer made of the photocurable insulating material described above is not particularly limited, and generally the thickness of each layer is 5 to 50 mm.
μm, radiation thickness 10-30 μm, total thickness 100
It is preferable to conduct the process so that it is less than μm (]8).

In the present invention, known methods can be used without particular limitation as the exposure method and development method for the layer made of photocurable insulating material formed on the printed wiring board. That is, the exposure can be carried out by irradiating the nuclear layer with the above-mentioned actinic rays through the progeny. Further, development may be carried out by removing the uncured portion after exposure with a liquid capable of etching the uncured photocurable insulating material9. The liquid is not particularly limited as long as it can dissolve the monounsaturated compound and/or polymeric binder that are the constituent components of the photocurable insulating material, and sodium phosphate, potassium phosphate, etc. Aqueous solutions of alkali metal phosphates such as carbonic acid) I
An aqueous alkali solution such as an aqueous solution of an alkali metal carbonate such as Jum, and an organic solvent such as 1.1.1-)lichloroethane, perchlorethylene, butyl cellosolve, toluene, and xylene are used.

Furthermore, heat treatment at 80 to 200° C. after development is a preferred embodiment since it can improve the properties of the formed insulating layer, such as adhesion to the printed wiring board, heat resistance, and solvent resistance.

In the present invention, the insulating layer is generally formed to cover the wiring pattern, conductive via holes, etc. of the printed wiring board except for a part of the earth pattern terminal.

In the present invention, the conductor 11 layer is generally formed on the insulation layer on the printed wiring board, including the ground pattern.
゜A conductive paste is generally used to form the conductive layer. As the conductive paste, any known conductive paste may be used without any restriction. For example, Epokin resin filled with metal powder such as copper, gold, silver, nickel, and carbon,
Those made of thermosetting resin such as phenol resin are preferably used. A conductive layer is formed by pattern-printing this on a required surface using a screen printing method or the like and curing it.

The thickness of the conductive layer is related to electrical resistance, but is usually 10μ to 1
It is preferable to adjust the thickness to 00 μm by adjusting the screen thickness, printing conditions, number of printings, paste viscosity, etc.

In the present invention, it is preferable to provide an overcoat layer in order to protect the surface of the electromagnetic shielding wiring board obtained by the above method from the external environment. The material for the overcoat layer is preferably one that has properties such as heat resistance, chemical resistance, surface hardness, moisture resistance, and high electrical insulation.

In some cases, a thermosetting resin based on Evochishi resin, which is commercially available as an unruder mask, a UR curable resin, etc. are used. Of course, the photocurable insulating material of the present invention can also be used as the overcoat layer.

The method of the present invention will be specifically explained using FIG.

FIG. 1 shows a processing process (21) showing a typical aspect of the method for manufacturing an electromagnetic shielding wiring board according to the method of the present invention. FIG. FIG. That is, (a
In J, after forming a layer 4 of a liquid photocurable insulating material on the substrate 1 having the wiring battens 2 and the ground pattern 5, in step (b), the layer 4 is applied to the core layer 4-a. Sensitivity and/or development i! l! Layers 4-1) of solid film-like photocurable insulating materials having different degrees of strength are laminated. Note that 3 is a through hole. Thereafter, exposure is performed through a photomask, and then development is performed to obtain a wiring board having an insulating layer in required portions, as shown in (C). Since the insulating layer is formed such that the amount of the remaining hardened layer decreases toward the surface, the sidewalls are expanded toward the surface. Therefore, in (dJ), the conductive paste 6 can be laminated on the insulating layer without involving gas, and by curing it, a good electromagnetic shield wiring board can be obtained.

〔effect〕

(22) As understood from the above description, according to the present invention, by using a specific photocurable insulating material in combination on the wiring pattern of a printed wiring board, the sidewall expands upward. An insulating layer is formed. Therefore,
When a conductive layer is formed covering the insulating layer, it is possible to completely prevent bacteria from entering the lower part of the sidewall of the insulating layer. Therefore, even if the printed wiring board has a high-density wiring pattern, an insulating layer and a conductive layer can be reliably formed thereon, significantly improving the reliability of the resulting electromagnetic shielding wiring board. be able to.

〔Example〕

EXAMPLES Hereinafter, in order to explain the present invention more specifically, Examples will be presented, but the present invention is not limited to these Examples.

In addition, the length of the table in "Part 1" indicates the first part. The specific methods for measuring photosensitivity and development time in Examples are as follows.

(1) Measurement of sensitivity A photocurable insulating material σ] solution was applied onto a copper-clad laminate,
Dry for 20 minutes at room temperature and 10 minutes at 80°C to a thickness of 25μ.
A layer of photocurable insulating material of m was formed. Then strike 97
Oak Manufacturing Co., Ltd. through a 740 step tablet
500 using a high-pressure mercury lamp exposure machine (manufactured by) IMW-6N model
Exposure was made at mt/crrL. After being left for 10 minutes after exposure, using a single needle% sodium carbonate aqueous solution (30°C),
Spray develop for 60 seconds (break point 50%),
Immediately sprayed and washed with water for 60 seconds.

The sensitivity was read from the remaining cured material.

(2) Measurement of development speed A photocurable insulating material solution was applied onto a copper-clad laminate and dried at room temperature for 20 minutes and at 80°C for 10 minutes to form a layer with a thickness of 25 μm and a size of 20 mm x 20 α. did. In the unexposed state, 1
% sodium carbonate aqueous solution (30° C.) at a spray pressure of 14 dino, and the Itii t was measured until the photocurable insulating material was completely dissolved and removed from the copper surface.

Implementation @1 (a), *Synthesis of synthetic unsaturated compounds A, TEPIC
-G (Nissan Kagaku Oka Co., Ltd. triglycidyl isone annulate, epoxy 110) 110 parts B, methacrylic acid 57 parts P-methoxyphenol 0.1 part co Propylene glycol monomethyl ether 53 parts, methyl violet 0. 01 parts 14 parts of the above compound A
After raising the temperature to 0°C and uniformly dissolving the mixture, it was cooled to 110°C, and compound B was added dropwise over 1 hour while maintaining the temperature at 110°C. After dropping compound B, the acid value of the reaction system was reduced to 1 or less at 110°C, and compound C was added to reduce the nonvolatile content to 75.
A solution (1) of (25) of a polymerizable unsaturated compound containing triglycidyl in cyanurate/acrylic acid (acid equivalent/epoxy equivalent ratio -273) type epothyl group in weight% was obtained.

(b) Preparation of photocurable insulating material (1) (87 parts of solution of polymerizable unsaturated compound obtained in aJ (solid content 66 parts)
, 35 parts of methyl methacrylate/butyl acrylate/methacrylic acid (7015/25 molar ratio) comonomer (weight average molecular weight 8), 5 flJs of benzophenone, 4.
05 parts of 4'-hisdiethylaminobenzophenone and 200 k't of propylene glycol monomethyl ether
Formulation L-1 was stirred and dissolved uniformly.

The photosensitivity of the photocurable material was 25 steps, and the development time for 100% (break point) was 30 seconds.

(C) Preparation of photocurable insulating material (2) In the above (b), 3 parts of benzophenone, 4.4'-
A resist (2) was prepared in the same manner except that 01 part of bisdiethylaminobenzophenone was used. The sensitivity of the photocurable insulating material was 19 steps, (26) and the development time for 100% breakpoint was 30 seconds.

(dJ Formation of shield plate Apply a solution of facilitable insulating material (1) to the etched substrate (FR-4, copper-clad laminate) on which the pattern has been formed, and dry at room temperature for 20 minutes and at 80°C for 10 minutes. , a resist layer with a thickness of 25 μm was formed. Then, in the same manner, a 25 μm thick layer of photocurable insulating material (2) was formed on the resist (]). Then, it was passed through a mask at 800 mt/, 7 f!! After exposure for 10 minutes, the film was spray developed using a 1% sodium carbonate aqueous solution at 30°C for 100 seconds (break point: 50%), and immediately washed with water for 60 seconds.The sensitivity was 22 steps. then 150°
C for 30 minutes to obtain an insulating layer with excellent dimensional accuracy comparable to that of a negative mask. When the insulating layer was examined using a scanning electron microscope, it was found that the sidewalls were expanding upward.

Next, a rolled pattern was formed on the insulating resist.

Thereafter, heat treatment was performed at 80° C. for 30 minutes to thermally harden the copper paste to obtain an electromagnetic rolled wiring board.

When ten electromagnetic shield wiring boards were manufactured by the above method, there was no conduction failure between the copper paste shield layer and the copper foil as-line when inspected using a continuity checker. 5
Example 2゜(a) Preparation of photocurable insulating material (3) Example 1 - 87 parts (solid content: 66 parts) of a solution of the epoxy group-containing monounsaturated compound obtained in at, methacrylic acid Methyl/butyl acrylate/methacrylic acid (601
5/35 molar ratio) copolymer (weight average molecular mottling: 8) 3
5 parts of benzophenone, 05 parts of 4°4'-bisdiethylaminobenzophenone, and 200 parts of propylene glycol monomethyl ether were mixed and uniformly dissolved with stirring.

When the development speed and sensitivity of the photocurable insulating material were measured, the development time was 17 seconds at a break point of 100%, and the sensitivity was 25 steps.

(b) Electromagnetic shielding was performed in the same manner as in Example 1-(d) for forming a shield plate, except that the photocurable insulating material (3) of this example was used instead of the photocurable insulating material (2). A wiring board was manufactured. When the cross section of the insulating layer after bostonia was observed with a scanning electron microscope, it was found that a wide sidewall was formed in the upper part.

When 10 electromagnetic shield wiring boards were manufactured using the above method, there was no conduction failure between the copper paste shield layer and the copper foil as-line when inspected using a continuity checker.

Example 3゜(a) Preparation of photocurable insulating material (4) Example 1-(
87 parts of the solution of the epoxy-containing heavily unsaturated compound obtained in a) (solid content (29) 66 parts), methyl methacrylate/butyl acrylate/methacrylic acid (6015/35 molar ratio) copolymer 11 average molecular weight 80,000) 35 parts, benzophenone 3 parts, 4.4'-
Blend bisdiethylamine benzophenone ol 1m (and 200 parts of propylene glycol monomethyl ether,
The mixture was stirred and dissolved uniformly.

When the development speed and sensitivity of the above photocurable insulating material were measured, the development time was 17 seconds at a break point of 100%;
The sensitivity was 19 steps at 500 mt/i.

(b) Forming a shield plate In the same manner as in Example 1-(d) except that the photocurable insulating material (4) of this example (&) was used instead of the photocurable insulating material (2). An electromagnetic shielding wiring board was manufactured.After the bostotinia, the cross section of the insulating layer was observed with a scanning electron microscope, and it was found that a wide sidewall was formed in the upper part.

When an IO electromagnetic shielding wiring board (30) was manufactured by the above method, there was no conduction failure between the copper paste shield layer and the copper foil as-line when inspected using a continuity checker. .

Comparative Example 1 An electromagnetic shield wiring board was produced in the same manner as in Example 1-(d), except that a photocurable insulating material (or the like) was used instead of the photocurable insulating material (2).

In the above manufacturing process, after the conductive layer was formed, the insulating layer was observed using a scanning electron microscope, and it was observed that the undercut of the sidewall was filled with copper paste while trapping air. Ta.

When 0 electromagnetic shield wiring boards were manufactured by the above method, a conduction failure between the copper paste shield layer and the copper foil ground line occurred at 15.3 points at all ground points when inspected using a continuity checker.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing a typical aspect of the method for manufacturing an electromagnetic shielding wiring board according to the present invention. In the figure, 1 is a board, 2 is a wiring button, 3 is a through hole, 4-a, 4
-b indicates a photocurable insulating forest material, 5 indicates a ground pattern, and 6 indicates a conductive paste.

Claims (1)

[Claims] (1) When manufacturing an electromagnetic shield wiring board by sequentially laminating an insulating layer and a conductive layer on a printed wiring board, photocuring of two or more layers with different photosensitivity and/or development speed is applied on the printed wiring board. 1. An electromagnetic shield wiring board characterized in that layers of insulating materials are laminated such that the amount of the cured layer remaining after exposure and development decreases toward the surface, and then exposure and development are performed to form an insulating layer. manufacturing method.