JPS60236284A - Method of producing printed circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a printed wiring board. More specifically, the present invention relates to a method of manufacturing a printed wiring board in which a wiring pattern is formed by electroless plating using a photoresist.

(Prior art) Conventionally, the main method for manufacturing printed wiring boards has been to use a copper-clad laminate and remove the steel in areas other than the wiring pattern by etching (referred to as the etched foil method). In contrast, there is a method of forming wiring patterns directly on an insulating laminate by electroless plating without using a copper-clad laminate (referred to as an additive method), but it is uneconomical to remove unnecessary copper. It has recently attracted attention due to its low manufacturing cost. However, since the deposition rate of electroless copper plating is extremely slow, it takes a long time (usually 5 to 60 hours).

High temperature (usually 60-80℃), high alkalinity (usually pH
11 to 13.5) must be immersed in the plating bath I/C, and a resist for electroless plating that can meet such severe conditions is required.

Traditionally, resists for this purpose are screen-printed with an ink containing epoxy resin and a hardener as the main ingredients.

Although it is formed from thermosetting K, the dimensional accuracy of lines is limited in printing, so it has been difficult to produce printed wiring boards with high density patterns using the additive method. Photoresists are suitable for forming high-density patterns, but commercially available photoresists for electrolytic plating or etching.

There was nothing that could withstand the harsh conditions of electroless plating. The present inventors proposed in Japanese Patent Application No. 56-199059 a method for manufacturing a printed wiring board using a photoresist that is resistant to electroless plating.

The present invention is a further improvement.

The photoresist used during electroless plating is either peeled off and removed after electroless plating or left as a permanent resist. As printed wiring boards become denser and busier, the line width and line spacing inevitably become narrower. However, it is impossible to completely peel off and remove the resist between narrow lines simply by dipping in a solvent, and it is not possible to completely peel off and remove the resist between narrow lines. This requires the use of a combination of force, which causes the disadvantage that narrow lines may float or move from the substrate. Furthermore, since the substrate after the resist is removed is uneven due to wiring lines, considerable skill is required to print the solder resist.

On the other hand, if the resist is left as a permanent resist, there is no problem mentioned above, but it is necessary to suppress the unnecessary precipitation of steel metal on the resist surface during electroless plating, and the resist (K) after plating is highly Properties required for a permanent resist include electrical insulation, soldering heat resistance, solvent resistance, and thermal shock resistance. To suppress copper metal precipitation on the resist surface.

The use of catalyst poisons such as sulfur-containing heterocyclic compounds and sulfur-containing alkali metal salts is known, but when the present inventors applied these heterocyclic compounds to the electroless plating solution, The heterocyclic compound elutes, reducing the plating speed, and in severe cases, causes the inconvenience of completely stopping the plating, and the alkali metal salt also tends to elute into the plating solution.

It has been found that when a large amount of this is used, the electrical insulation properties of the resist deteriorate and it cannot be used as a permanent resist. Furthermore, if the catalyst poison is a solid particle that is insoluble in the solvent,
It was discovered that during image exposure for image formation, light is scattered on the particle surface, making it impossible to form a high-density pattern.

The present inventors have conducted various studies and found that the use of a photopolymerizable unsaturated compound having at least two terminal ethylene groups and a covalently bonded sulfur atom in the molecule eliminates the above-mentioned disadvantages and yields favorable results. I found out that it can be done.

When the unsaturated compound is used as a catalyst poison in a photoresist, there is almost no decrease in the plating rate, but the reason for this is that the unsaturated compound undergoes photopolymerization and crosslinking upon exposure to light.

This is thought to be due to almost no elution into the plating bath.

(Objective of the Invention) An object of the present invention is to provide a method for manufacturing a high-precision printed wiring board using an additive method.

(Structure of the Invention) The present invention provides (1) a photopolymerizable unsaturated compound having at least two terminal ethylene groups of one or more types on the surface K, +al of an insulating substrate on which electroless plated steel is to be precipitated in a required portion; 20-75 parts by weight, (b) linear polymer compound 20-7
5 parts by weight and K (C1) containing 0.5 to 10 parts by weight of a sensitizer or (and) sensitizer system that generates free radicals by active light, and containing at least 2 parts by weight of one or more terminal ethylene groups of the above fal. 0.1~ of photopolymerizable unsaturated compounds
Step of forming a layer of a photosensitive resin composition which is an unsaturated compound having an intramolecular pressure of 100% by weight of covalently bonded sulfur atoms (2) After irradiation with imagewise actinic light, the layer is developed and exposed to light on the surface of the substrate. Step (3) of forming a negative pattern of the photosensitive resin composition; Step (4) of re-irradiating with actinic light; and (4) forming a wiring pattern by electroless steel plating using the negative pattern of the photosensitive resin composition on the surface of the substrate as a plating resist. The present invention relates to a method for manufacturing a printed wiring board, which includes a step of forming a printed wiring board.

The method of manufacturing a printed wiring board proposed by the present invention will be described in detail below.

The method of manufacturing a printed wiring board proposed by the present invention includes the step of forming a layer of a photosensitive resin composition on the surface of an insulating substrate on which electroless plated steel is to be deposited on the required portions.

As the insulating substrate, a metal cored substrate such as a laminated board of paper phenol, glass epoxy, etc., an iron enamel board, a board with an epoxy resin insulating layer formed on both sides of an aluminum board, etc. can be used. These boards.

It is also possible to apply a plating catalyst to the inner wall of the through hole by immersing it in a solution containing a plating catalyst after drilling.

As such a plating catalyst solution, sensitizer H8-101B manufactured by Hitachi Chemical Co., Ltd., etc. can be used. To ensure good adhesion of the catalyst to the surface of the substrate.

It is preferable to apply an adhesive layer in order to improve the adhesion of the electroless plated steel to the substrate where lubrication occurs.

As the adhesive, those known as additive adhesives such as phenol-modified nitrile rubber adhesives can be used. A compound serving as a plating catalyst can also be included in the adhesive.

A laminate in which a compound such as an internal KPd compound which serves as a catalyst for electroless steel plating is dispersed is also a preferred substrate when depositing electroless plated steel on the inner wall of a through hole. A laminated plate ACL-B-161 manufactured by 1 Hitachi Chemical Co., Ltd. is a substrate in which an adhesive layer containing a plating catalyst is formed on the surface of a glass epoxy laminate containing a plating catalyst therein. When such a substrate is used, the step of attaching the Larata K plating catalyst is not necessary. In order to improve the adhesion of the plating catalyst and the adhesion of the deposited electroless plated steel, it is preferable to roughen the surface of the adhesive layer before the electroless plating treatment. As a roughening method, immersion in an acidic solution containing sodium dichromate or chromic acid may be used, but as is well known, the roughening process is carried out before the electroless steel plating process by photosensing as described in the next section. It does not matter whether it is removed before the layer of the transparent resin composition is formed or after the resist pattern is formed.

The photosensitive resin composition used in the present invention contains as an essential component a photopolymerizable unsaturated compound having at least two terminal ethylene groups of one or more types.

Examples of such unsaturated compounds include trimethylolpropane, trimethylolethane, pentaerythritol, dipentaerythritol.

1.6-hexanediol, propylene glycol.

Mention may be made of acrylic or methacrylic esters of polyhydric alcohols such as tetraethylene glycol and dibroneopentyl glycol. Further, reaction products of compounds having at least two epoxy groups such as Klj-like aliphatic epoxy resins, epoxidized novolak resins, bisphenol A-epichlorohydrin epoxy resins, and acrylic acid or methacrylic acid, diol monoacrylates, etc.
1) Reaction products of monomethacrylates or diisocyanates, phosphorus-containing acrylic acid derivatives, such as trisacryloxyethyl phosphate, etc. may also be used. In view of the characteristics of the resist formed, a patent application was filed in 1983.
Trimethylhexamethylene diisocyanate, diol monoacrylate or diol monomethacrylate described in No. 131322 and Japanese Patent Application No. 55-141682, and optionally other incyanate compounds or (and) other alcohol compounds are reacted. A urethane acrylate compound or a urethane methacrylate compound obtained by this method is preferable.

In the present invention, 0.1 to 1 of photopolymerizable unsaturated compounds having at least two terminal ethylene groups of one or more
00% by weight is an unsaturated compound having a covalently bonded sulfur atom in the molecule. Examples of such unsaturated compounds include compounds of the following general formulas (3) and (B) obtained using bisphenol S as a raw material.

Acrylic esters and methacrylic esters of polyhydric alcohols having a sulfur atom, such as thiodiglycol and bis(2-hydroxy)sulfone, can also be used.

If the amount of the unsaturated compound having a covalently bonded sulfur atom in the molecule is less than 0.1% by weight, the effect of suppressing copper metal precipitation will be small, and an amount of 1% by weight or more is particularly preferable.

If the amount of the unsaturated compound having a covalently bonded sulfur atom in the molecule is less than 100% by weight, the photopolymerizable unsaturated compound having at least two terminal ethylene groups and having no covalently bonded sulfur atom in the molecule is used. Contains.

In the present invention, the content of the photopolymerizable unsaturated compound having at least two terminal ethylene groups of one or more types is 20 to 7 from the viewpoint of electroless plating resistance, soldering heat resistance, and thermal shock resistance.
The range is 5 parts by weight.

The photosensitive resin composition used in the present invention contains a linear polymer compound as an essential component. As the linear polymer compound, for example, a thermoplastic polymer described in Japanese Patent Publication No. 15932/1984 can be used. Preferred linear polymer compounds include vinyl monomers such as methyl methacrylate, ethyl acrylate, acrylic acid, styrene, 2-hydroxyethyl methacrylate, t-butylaminoethyl methacrylate, acrylamide, acrylonitrile, and vinyl acetate. Vinyl polymer compounds obtained by polymerization or copolymerization, synthetic rubbers such as butadiene/acrylonitrile copolymers, butadiene/acrylonitrile/styrene copolymers, linear polyurethane compounds, alcohol-soluble nylon, etc. The content of the linear polymer compound is 20% based on electroless plating resistance, soldering heat resistance, and thermal false impact resistance.
The range is 75 parts by weight.

The photosensitive resin composition used in the present invention contains 0.5 to 10 parts by weight of a sensitizer or/and sensitizer system that generates free radicals when activated by actinic light. Sensitizers that can be used include substituted or unsubstituted polynuclear quinones such as 2-
Ethylanthraquinone.

α such as 2-t-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2゜3-diphenylanthraquinone, ketoaldonyl compounds such as diacetyl and benzyl, benzoin, hivalon, etc.
-ketaldonyl alcohols and ethers, α-hydrocarbon-substituted aromatic acyloin a, e.g. α-phenyl-
Benzoin.

Examples include aromatic keto/groups such as α,α-jethoxyacetophenone, benzophenone, and 4,4'-bisdialkylaminobenzophenone, and these may be used alone or in combination. Sensitizer systems that can be used include 2,4.5-1 Really imidazole dimer, 2-mercaptobenzoquinazole, leuco crystal violet, Tris(4
-diethylamino-2-methylphenyl)methane, etc. can be exemplified. Moreover, it is not photoinitiated by itself.

Additives can be used which, when used in combination with the previously mentioned materials, result in an overall sensitizer system with better photoinitiation performance. Examples include tertiary amines such as triethanolamine for benzophenone.

The photosensitive resin composition used in the present invention can further contain other subsidiary components. The subsidiary components include thermal polymerization inhibitors, dyes, pigments, coating properties improvers, etc., and the selection of these is done based on the same consideration as for ordinary photosensitive resin compositions.

The method of manufacturing a printed wiring board proposed by the present invention necessarily includes the step of forming a layer of the photosensitive resin composition described in detail above on the surface of an insulating substrate on which electroless plated steel is to be deposited on the required portions. . The step of forming a layer of a photosensitive resin composition on the surface of an insulating substrate on which electroless plated steel is to be deposited can be carried out by a conventional method. For example, a photosensitive resin composition is uniformly dissolved or dispersed in a solvent such as methyl ethyl ketone, toluene, methylene chloride, etc., and applied on the surface of an insulating substrate on which electroless plated steel is to be deposited by a degg coating method, a flow coating method, etc. This is done by drying with a solvent.

A solution of the photosensitive resin composition is not directly applied onto the substrate, but is coated and dried on the support film by a known method such as knife coating or roll coating, thereby forming a layer of the photosensitive resin composition on the support film. After manufacturing a photosensitive element having
It is also possible to form a layer of the photosensitive resin composition on the surface of the substrate by laminating the photosensitive element under heat and pressure by a known method on the surface of an insulating substrate on which electroless plated steel is to be deposited.

Polyester film is used as the support film.

Polypropylene film, polyimide film.

Known films such as polystyrene film can be used.

The method using a photosensitive element is preferable because it is easy to make the coating thickness uniform and adhesives with low solvent resistance can also be used.

The thickness K of the layer of the photosensitive resin composition formed is K 1I
Although there is no limit, when producing a high-density printed wiring board, it is preferable that the thickness be approximately the same as the thickness of plated steel deposited by electroless plating. For example, when performing plating with a thickness of 35 μm, the thickness of the photosensitive resin composition layer is 35 μm.
A range of 0 to 40 μm is preferred. In this way, by adjusting the thickness of the plated steel and the resist to almost match each other, there is no problem!
The surface of the substrate after deplating becomes almost smooth except for through holes, and printing of solder resist can be carried out very easily.

The method of manufacturing a printed wiring board proposed by the present invention is to apply a negative pattern of a photosensitive resin composition on the surface of an insulating substrate to deposit electroless plated steel on the required areas by irradiation with active light and development. It always includes the step of forming. Preliminary irradiation with active light can be carried out by using a light source such as an ultra-high-pressure water lamp or a high-pressure water scissor lamp, and by exposing the material through a negative mask.

It is also possible to perform pre-scanning with a laser beam or the like focused on a minute cross-sectional area. Development can be carried out by immersing the substrate having a layer of the photosensitive resin composition that has been previously irradiated with actinic light in a developing solution such as 1,1.1-trichloroethane, or by spraying the developing solution. Ru.

The method for manufacturing a printed wiring board proposed by the present invention necessarily includes a step of re-irradiating with actinic light after forming a negative pattern by development. Re-irradiation of the activation light can be carried out by irradiating the entire surface of the substrate using a light source such as an ultra-high pressure mercury lamp or a high-pressure mercury lamp.

The negative pattern Vi of the photosensitive resin composition thus formed shows excellent alkali resistance.

In order to prevent contamination of the plating bath, the negative pattern that has been reirradiated with active light is preferably subjected to a heat treatment at 100 to 200°C.

The method of manufacturing a printed wiring board proposed by the present invention necessarily includes the step of forming a wiring pattern from electroless steel plating K using the negative pattern of the photosensitive resin composition obtained by the above method as a plating resist.

Electroless plating solution includes copper salt, complexing agent, reducing agent and pH
Plating solutions containing conditioning agents can be used.

As the copper salt, for example, sulfuric acid steel, nitric acid steel, cupric chloride, etc. can be used. As the complexing agent, for example, ethylenediaminetetraacetic acid, N, N, N', N'-tetrakis-2-hydroxypropylethylenediamine, Rochelle salt, etc. can be used. Formalin is preferred as the reducing agent. It is also commonly used as a pH adjuster.

Alkali hydroxide and sodium hydroxide are used.

Potassium hydroxide etc. Furthermore, various additives are sometimes added for the purpose of increasing the stability of the plating bath, improving the properties of the copper gold that is precipitated, and so on. The conditions of the plating bath are such that the copper concentration is 5 to 159/1, depending on the stability of the plating bath, the characteristics of the deposited copper metal, etc. pH11-13. A bath temperature of 60 to 80°C is preferred. When electroless steel plating is completed, it goes without saying that the plating catalyst should be attached and/or activated if necessary.

After electroless plating, when a negative pattern of a photosensitive resin composition used as a plating resist is peeled off and removed, particularly the thin line portion of the wiring line formed by electroless plating tends to peel off from the substrate.

In addition, since unevenness caused by wiring lines makes it difficult to form a solder resist, it is preferable to leave the negative pattern of the photosensitive resin composition as a permanent resist without peeling or removing it.

After copper pattern formation, to protect the copper surface from oxidation,
Or, if that part becomes an electrical connection part, the purpose is to reduce contact resistance.

The entire copper pattern or a desired partial pressure can be coated with solder using a solder repeller, or gold plating, tin plating, etc. can be performed. Solder the copper surface.

After covering with a metal such as gold or tin, a solder mask can be formed on the required portions of the substrate while leaving the surface of the copper or copper surface. This solder mask can also be used as a resist for coating only desired portions of the copper pattern with solder or the like. Although the solder mask can be formed by printing an epoxy resin ink by screen printing or the like and curing it, the photosensitive resin composition used in the present invention may be used.

It can also be used to form high-precision solder masks using photographic methods. Printed wiring boards manufactured in this manner can be used in various ways using known methods, such as for soldering electronic components, but printed wiring boards after electroless copper plating can be used in multiple layers. It can also be used as an inner layer board for printed wiring boards.

(Example) Next, an example of the present invention will be shown. The present invention is not limited to the examples shown here. "Parts" in Examples and Comparative Examples indicate parts by weight.

Reference Example 1 Synthesis of Urethane Acrylate Compound Toluene (solvent) 1200 parts B 1,6-hexanediol 472 parts (8 equivalents) Toluene (solvent) 88 parts D Methanol (terminator) 32 parts Equipped with a cooling pipe, nitrogen gas introduction pipe and dropper. The mixture was added to a reactor with a S capacity of about 51 which can be heated and cooled, and the temperature was raised to 60°C while stirring. While maintaining the reaction temperature at 55 to 65°C, KB was added dropwise over about 3 hours. At a temperature of 60℃ after the completion of B dropping, about 2
After that, C was uniformly added dropwise at a temperature of 60° C. over about 3 hours. After the C dropwise addition was completed, the reaction temperature was gradually raised to 80° C. over about 5 hours. Thereafter, the temperature was lowered to tl-60°C, D was added, and stirring was continued for about 1 hour. In this way, a solution of a urethane acrylate compound was obtained. Thereafter, it was dried under reduced pressure to obtain a viscous urethane acrylate compound.

Example - Benzophenone 4 parts p-methoxyphenol o, i parts Crystal violet 0.1 part Methyl ethyl ketone 80 parts A solution of a photosensitive resin composition was prepared using the above formulation.

Additive method substrate ACL-E-1 manufactured by Hitachi Chemical ■
61 (a substrate in which a phenol-modified nitrile rubber adhesive containing a plating catalyst was applied to a thickness of about 30 μm on both sides of a glass epoxy laminate containing a Pd-based plating catalyst) was coated with NC.
2. Drill a through hole with a diameter of 1.0 mm. ．． 54m
A test board with holes spaced at m intervals was made. This test substrate was polished with a nylon brush, washed with water, heated and dried at 80°C for 10 minutes, and then a solution of the photosensitive resin composition described above was applied by dip coating, followed by solvent drying at 80°C for 20 minutes. The test negative mask shown in Fig. 1 was brought into close contact with both sides of the test substrate on which a layer of photosensitive resin composition with a thickness of about 25 μm was formed after being dried by pressure. , exposed at l 20 mJ/cm",
After heating at 80° C. for 5 minutes, the negative mask was peeled off. 1 indicates the opaque part of the negative mask, 2 indicates the transparent part of the negative mask, and the unit of number is ichi.

Next K 1.1.1-) 20℃ using dichloroethane
Spray development was carried out for 50 seconds. After development, heat dry at 80°C for 10 minutes, and e2J using an ultraviolet irradiation device manufactured by Toshiba Denzai.
The test substrate on which the resist image had been formed in this way was irradiated with ultraviolet rays in an amount of 42% fluoroboric acid 1j' and 209% sodium dichromate. 15 in the dissolved 40℃ liquid
The exposed portion of the adhesive layer was roughened by immersion for 5 minutes, and the exposed portion of the adhesive layer was washed with water.Then, the sample was immersed in hydrochloric acid having a concentration of 3N for 5 minutes, and then washed with water. This test board.

Cu 804 ・5 H2O 15ta/l, ethylenediaminetetraacetic acid 30g/l, 371HCHO aqueous solution 1
0m1! /V.

It was immersed for 15 hours in an electroless steel plating solution VC70°C containing 25n1g/V of sodium cyanide and adjusted to HI2.5 with NaOH, and after washing with water, it was dried at 80°C for 10 minutes. There was no cranking in the resist, no lifting or peeling from the substrate, and a copper pattern with a thickness of about 30 μm was formed in the part of the substrate where there was no resist, following the pattern of the negative mask. An electroless steel plating film with a thickness of about 30 μm was also formed on the inner wall of the through hole. There was no excess copper metal deposited on the resist surface. Rosin-based Franks A-226 (manufactured by Tamura Kaken ■) was added to the printed wiring board made in this way.
was applied and immersed in a 260°C solder bath for 10 seconds, and then immersed in 25°C Triclean for 20 seconds to remove the flux. There was no cranking in the resist, and no lifting or peeling from the board was observed, indicating that the resist had excellent soldering heat resistance. Furthermore, MIL-8TD-202E
107D Condition B (-65℃, 30 minutes, 5 minutes at room temperature
A thermal shock test was conducted for 50 cycles at 25° C. for 30 minutes, but the resist showed no cranking, and no lifting or peeling from the substrate was observed, indicating that it has excellent long-term reliability.

Example 2 Aloex@M-205 20 parts Benzophenone 27 parts Michler's ketone 0.3 parts p-methoxyphenol 0.1 part Victoria Pure Blue 0.05 parts Methyl ethyl ketone 80 parts Toluene 40 parts The above formulation was carried out using the apparatus shown in FIG. A solution 10 of the photosensitive resin composition was spread evenly on a 25 μm thick polyethylene terephthalate film 16 and dried in a hot air convection dryer 11 at 80 to 100° C. for about 10 minutes. The dry thickness of the photosensitive resin composition layer was approximately 35 μm. On the layer of the photosensitive resin composition, a polyethylene film 17 having a thickness of about 25 μm was further laminated as a cover film as shown in FIG. 2 to obtain a photosensitive element.

In FIG. 2, 5 is a polyethylene terephthalate film roll, 6, 7.8 are rolls, 9 is a knife, 12U polyethylene film roll, 13.
14 is a roll, and 15 is a photosensitive element winding roll.

A test board for additive method ACL-E-161 with through holes of diameter o and suni drilled at 2.54 mm intervals using an NC drill was polished with Scotchbrite manufactured by Sumitomo 3M ■, washed with water, and heated and dried at 80°C for 15 minutes. did. The photosensitive elements obtained above were laminated on both sides of this test substrate using an A-500 model laminator manufactured by Akebono Sangyo. This 2
The test negative masks shown in Figure 1 were brought into close contact with both sides of the test board, exposed to light at 100 mJ/cm'', and heated at 80°C for 10 minutes.After being left at room temperature for 20 minutes, the polyester film was peeled off from the support film. 1,1.1-) Spray developed using dichloroethane for 70 seconds and 1
Dry for 0 minutes. This test board was used in the same manner as in Example 1 at 2J/
After re-irradiation with an' ultraviolet rays, heat treatment was performed at 160° C. for 20 minutes, and after roughening treatment, electroless steel plating was performed for 20 hours in the same manner as in Example 1. There was no occurrence of resist VcFi scratches, no peeling from the substrate, and a highly accurate copper pattern (copper thickness: about 35 μm) following the negative mask pattern lc was formed on the substrate. There was no excess copper metal deposited on the resist surface. After this, soldering was carried out in the same manner as in Example 1, and a thermal shock test was conducted for 50 cycles, but no cranking occurred in the resist, and no lifting or peeling from the substrate was observed.

Comparative Example 1 Benzophenone 2.7 parts Ketone 0.3 parts p-methoxyphenol 0.1 part Victoria Pure Blue 0.05i Methyl ethyl ketone 80 parts Toluene 40 parts Using a solution of the photosensitive resin composition with the above formulation Except for this, a photosensitive element was prepared in the same manner as in Example 2, and then electroless plating was performed using the photosensitive element, but 500 extra copper metal deposits with a diameter of several tens of μm were deposited on the resist surface. cII+2 or more, I found a part where there was an electrical short between the copper patterns. The copper pattern formed from electroless steel plating K was plated to a copper thickness of approximately 35 μm.

Comparative Example 2 A photosensitive element was prepared in the same manner as in Example 2, except that a solution of a photosensitive resin composition in which 2 parts of 2-mercaptobenzothiazole, which is a catalyst poison, was added to the formulation of Comparative Example 1 was used. First, electroless copper plating was performed using the photosensitive element.

Although there was no excess copper metal deposited on the resist surface, the copper thickness of the copper pattern formed from electroless steel plating K was about 5 μm. It is thought that a large amount of benzothiazole in the resist eluted into the plating solution and contaminated the plating solution, resulting in a significant decrease in the plating speed.

Example 3 Benzophenone 27 parts Mihiraketone 0.3 parts Victoria Pure Blue 0.02 parts Phthalocyanine Green 0.3 parts Methyl ethyl ketone 50 parts Toluene 50 parts A solution of the photosensitive resin composition having the above formulation was used, and the rest was as in Example 2. A similar operation was carried out to obtain a photosensitive element having a layer of photosensitive resin composition having a thickness of about 35 μm.

The additive method substrate ACL-E-161 was polished with Scotch prite, washed with water, and dried by heating at 80° C. for 10 minutes.

The photosensitive element obtained above was laminated on the surface of this test substrate in the same manner as in Example 2. Next KIIj! Width 100μ
m, a negative mask containing a high-density pattern with a line spacing of 100 μm is adhered, ■Oak made new Phoenix 300
Exposure at +70 mJ/cm2 using a 0-type exposure machine,
It was heated at 80°C for 5 minutes. After being left at room temperature for 20 minutes, the support film was peeled off and developed using 1,1.1-)lichloroethane at a rotation speed of 500 RPM for 2 minutes using a spin spray device manufactured by Kyoei Semiconductor ■ at 80°C.
and dried for 10 minutes.

This test substrate was re-irradiated with 2 J/cm'' ultraviolet light in the same manner as in Example 1, then heat treated at 160°C for 20 minutes, and after roughening treatment in the same manner as in Example 1, electroless steel plating was performed for 20 hours. There were no cracks in the resist, and no lifting or peeling from the substrate.

A highly accurate copper pattern (copper thickness of about 35 μm) was formed according to the pattern of the negative mask. There was no excess copper-gold paulownia deposited on the resist surface. A solder resist ink USR-20 (made by Tamura Kaken ■) was further printed on the surface of the test board produced by pressing in this manner. Since the substrate surface was almost smooth, the solder resist could be easily formed in one printing.

After this, a high-pressure mercury lamp (manufactured by Toshiba Denzai ■ 1 (5600L/8)
W) after irradiating with ultraviolet rays in an amount of 2 J/cIII2.

Soldering was performed at 260° C. for 20 seconds using flux, but no abnormalities such as lifting or peeling of the resist were observed.

Comparative Example 3 Electroless steel plating was performed in the same manner as in Example 3 to obtain a test board on which a highly accurate copper pattern (copper thickness of about 35 μm) was formed. In order to remove the resist used for this fixing, it was immersed in methylene chloride at 25° C. for 10 minutes, but the resist could not be removed. While further immersed in methylene chloride.

Attempts were made to remove the resist using a brush, but the resist could not be removed without damaging the highly precise copper line.

Comparative Example 4 A test board on which a high-precision copper pattern (copper thickness approximately 30 μm) was formed was obtained by applying pressure and performing electroless copper plating in the same manner as in Example 3, except that 2 J/cm2 ultraviolet rays were not irradiated after development. Ta. This is thought to be because the copper thickness was slightly thinner than in Example 3, and re-irradiation with ultraviolet rays was omitted, which contaminated the plating bath and caused the plating rate to decrease slightly.

The test substrate was immersed in methylene chloride at 25° C. for 5 minutes, and the resist was completely removed by gently moving the substrate up and down. In addition to this, the surface of the test board is uneven due to the copper line, so the line width is particularly important.

It was difficult to fill a high-density area with a line spacing of 100 μm with resist ink without leaving any air bubbles.

Example 4 Urethane acrylic obtained in Reference Example 1 60 parts Rate compound Penz°phenone 3 parts Michler's ketone o, i part p-methoxyphenol 0.1 part Phthalocyanine Green 03 parts Victoria Pure Blue 0.05 part Methyl ethyl ketone 80 parts Toluene 40 A photosensitive element was prepared in the same manner as in Example 2 except that a solution of the photosensitive resin composition having the above formulation was used, and then electroless plating was performed using the photosensitive element.

There were no cracks in the resist, no lifting or peeling from the substrate, and a highly accurate copper pattern (copper thickness about 35 μm) was formed on the substrate according to the pattern of the negative mask.

There was no excess copper metal deposited on the resist surface. Then, soldering was performed in the same manner as in Example 1, and a thermal shock test was conducted for 50 cycles, but no cranking occurred in the resist.

Further, no lifting or peeling from the substrate was observed.

Example 5 70"M 205 50 parts Benzophenone 3 parts Michler's ketone 0.1 part p-methoxyphenol 0.1 part Phthalocyanine green 0.3 part Victoria Pure Blue o, oss Methyl ethyl ketone 80 parts Toluene 40 parts Photosensitive with the above composition A photosensitive element was prepared in the same manner as in Example 2, except that a solution of the photosensitive resin composition was used, and then electroless plating was performed using the photosensitive element.

There were no cranks in the resist, no lifting or peeling from the substrate, and a highly accurate copper pattern (copper thickness of about 35 μm) was formed on the substrate according to the pattern of the negative mask.

There was no excess copper metal deposited on the resist surface. After this, soldering was carried out in the same manner as in Example 1, and a thermal shock test was conducted for 50 cycles, but no cracks were observed in the resist.

Further, no lifting or peeling from the substrate was observed.

(Effects of the Invention) As shown in the examples, by the method for manufacturing a printed wiring board according to the present invention, a printed wiring board with high density and high precision can be obtained by an additive method.

It should be noted that the above-mentioned embodiments are merely examples of the present invention, and various modifications and usage methods may be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a test negative mask used in Examples, and FIG. 2 is a schematic diagram of a manufacturing apparatus for photosensitive elements used in Examples. Explanation of symbols 1... Opaque part of negative mask 2... Transparent part of negative mask 5... Polyethylene terephthalate film <Base roll 6.7.8... Roll 9... Knife 10... Photosensitive Solution of resin composition 11...Dryer 12...Polyethylene film <Drawing roll 13,
-14...Roll 15...Photosensitive element winding roll 16...
Polyethylene terephthalate film 17...Polyethylene film Figure 1 Figure 20

Claims (1)

[Claims] 1, +11 A photopolymerizable unsaturated compound having at least two terminal ethylene groups of type X or more on the surface of an insulating substrate on which electroless plated steel is to be deposited on the required parts 20-75 parts by weight, (b) linear polymer compound 20-7
5 parts by weight and 0.5 to 10 parts by weight of a sensitizer or (and) sensitizer system that generates free radicals by C1 active light, and at least one or more terminal ethylene groups in (a) above. 0.1 to 2 photopolymerizable unsaturated compounds
Step (2) of forming a layer of a photosensitive resin composition made of an unsaturated compound having 100% by weight of covalently bonded sulfur atoms in the molecule (2) irradiation with imagewise actinic light and development to form a layer on the surface of the substrate. Step (3) of forming a negative pattern of the photosensitive resin composition (3) Step of re-irradiating with actinic light (4) Using the negative pattern of the photosensitive resin composition on the surface of the substrate as a plating resist by electroless steel plating A method for manufacturing a printed wiring board, comprising the step of forming a wiring pattern. 2 Claim 1 in which the negative pattern of the photosensitive resin composition remains as a permanent resist even after electroless steel plating
A method for manufacturing a printed wiring board as described in Section 1. 3. Claim 1 or 2 states that the thickness of the layer of the photosensitive resin composition formed in (1) is approximately the same as the thickness of the plated steel deposited by electroless steel plating K. A method for manufacturing a printed wiring board. 4. An unsaturated compound having a covalently bonded sulfur atom in the molecule is at least one of the group consisting of the following general formula and (Bl).
A method for manufacturing a printed wiring board according to claim 1, 2, or 3, which requires a seed.・・・・・・(3) OH OH ・・・・・・・・・(B1 5. Step of forming a layer of a photosensitive resin composition. Forming a layer of a photosensitive resin composition on a support film. Claim 1, which is a method of laminating photosensitive elements having
The method for manufacturing a printed wiring board according to item 2, item 3, or item 4.