JPH0936545A - Manufacture of printed-wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contrive to improve the resolving power of a photosetting resin layer for 'a buried tenting method' use in the manufacture of a printed-wiring board having a small-diameter through hole. SOLUTION: In a process for laminating photosetting resin laminated materials, which respectively comprise a support, on both surfaces of a metal- coated insulating plate having a through hole, a photosetting resin layer has a viscosity poise of a poise of 10<4> to 5×10<5> at 90 deg.C, a thickness of 30 to 80μm and an ultraviolet transmittance of 20% or more and less than 40% to ultraviolet rays of a wavelength of 365nm and contains at least one kind of a 2,4,5-triaryl imidazoril dimer and at least one kind of a P-type aminophenyl ketone. The content, which is added the contents of both of these together, of the resin layer is set at 0.1 to 5.1wt.% and the depth of the photosetting resin layer, which is extended from the inner peripheral edge of the hole onto the inner wall surface of the hole along the inner wall of the hole, is made 0.5 times or deeper than the thickness of a metal conductor layer on each surface of the insulating plate. Thereby, even in the case where the position of a mask is shifted from that of the hole, a good tenting film can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for manufacturing a printed wiring board having a small diameter through hole.

[0002]

2. Description of the Related Art A method called a tenting method is often used for manufacturing printed wiring boards having through holes. The tenting method is a so-called dry film resist (hereinafter, referred to as "DF") including a support and a photocurable resin layer.
R ". ) Is used.

In the tenting method, a DFR is laminated on a metal-coated insulating plate (hereinafter referred to as a "substrate") to cover both end openings of each through hole in a photocurable resin layer, and then a wiring pattern mask is formed. A cured resist (called a tenting film) that covers the through-holes is formed by exposing the through holes through the substrate, and after removing the photocurable resin layer in the unexposed area with a developing solution, on the substrate other than the cured resist image. Is a method for producing a printed wiring board having a through hole by etching the metal conductor layer. DF on the board
The process of laminating R is called a laminating process.

The hardened resist layer formed so as to cover the through hole is held by being adhered to the surface of the conductor layer (hereinafter referred to as "land") formed around the through hole, and the etching solution is used. Are prevented from entering the through hole. Therefore, in the tenting method, it is essential in designing to make a land, and its width is 0.
It was around 5 mm.

However, in recent years, the density of printed wiring boards has been increased, and small-diameter through-holes having a smaller diameter and narrower lands have been widely used. The small diameter through hole has a diameter of 0.5 mm or less and a land width of 0.1 mm or less, preferably 0.05 mm or less.

If the land width is narrow, the cured resist film covering the small diameter through hole is not sufficiently adhered to the substrate, and defects often occur due to the penetration of the etching solution into the small diameter through hole, making it practically impossible to manufacture. Is. Therefore, conventionally, the hole filling ink method and the plating method, which are more complicated and costly than the tenting method, have been used.

On the other hand, the applicant of the present invention embeds a photo-curable resin layer of DFR into a small-diameter through hole to a certain depth.
Moreover, by sufficiently photo-curing, a good tenting film is formed even if the positions of the mask and the through holes are displaced by more than the land width. A technique that can be realized by a touching process has been disclosed (Japanese Patent Laid-Open No. 3-236956). This was put to practical use and spread as the "embedded tenting method".

[0008]

The miniaturization of the conductor pattern of the printed wiring board has progressed year by year, and accordingly, the DFR is required to have a higher resolution. In order to stably manufacture a so-called five-pin board, a DFR resolution of 60 μm or less has been required. However, according to the above-mentioned conventional technique, the resolution is likely to change depending on the quality of the contact between the wiring pattern mask and the DFR laminated on the substrate and the roughened state of the surface of the substrate, and in some cases, the resolution becomes worse than 60 μm. Therefore, a DFR having a stable and high resolution has always been demanded.

In addition, in order to facilitate the adhesion of the photocurable resin layer of DFR to the substrate used for the production of a printed wiring board during lamination, it is common to make a small unevenness on the surface before laminating. is there. The process of roughening the substrate surface in this way is called a surface-adjusting process, and there are various methods, but in recent years, there have been many jet-scrub surface-adjusting processes that do not have anisotropy in the surface-adjusting state and surface adjustment by chemical polishing liquid. There is. However, the technique disclosed by the present applicant (Japanese Patent Laid-Open No. 3-2
No. 36956), it is difficult to obtain the original resolution with a substrate that has been subjected to the above-mentioned jet scrub surface preparation or chemical polishing solution surface preparation, and from this point as well, a DFR having a stable and high resolution is always required. It was

In view of the above circumstances, the present invention has an object to improve the resolution of the photocurable resin layer for "embedding tenting method" in the production of a printed wiring board having a small diameter through hole.

[0011]

As a result of intensive studies to achieve the above object, surprisingly, at least one 2,4,5-triaryl as a photopolymerization initiator was added to the photocurable resin layer. By adding the imidazolyl dimer and at least one p-aminophenyl ketone, it has the ability to form a good tenting film even when the mask and the through hole of the substrate are misaligned, As a result, they have found that the resolution is significantly improved, and have reached the present invention.

That is, according to the present invention, there is provided a method of manufacturing a printed wiring board having a small-diameter through hole (through hole), which comprises (1) photo-curing including a support on both surfaces of a metal-coated insulating plate having a through hole. In the step of laminating a photosensitive resin laminate, the photocurable resin layer is (a) 10 ^{4 to} 5 × at 90 ° C.
At least one of 2, 4, 5 having a viscosity of 10 ⁵ poise, (b) a thickness of 30 to 80 μm, and (c) a UV transmittance of 20% or more and less than 40% for UV having a wavelength of 365 nm. A triaryl imidazolyl dimer and at least one p-aminophenyl ketone, the total content of both being 0.1 to 5.1% by weight, from the inner peripheral edge of the through hole to the inner wall of the through hole An index n defined as a ratio of a depth of the photocurable resin layer extending along the inner wall surface to a thickness of the metal conductor layer on each surface of the metal-coated insulating plate.
The photo-curable resin layer on each surface of the metal-coated insulating plate is exposed to ultraviolet light through a predetermined transparent pattern mask to be embedded in the through hole so as to be 0.5 or more. Forming a photo-cured resin latent image covering the opening of (3) developing the resin latent image with a developing solution to form a cured resin image, and (4) other than the cured resin image as the etching resist. There is provided a method for manufacturing a printed wiring board, which comprises etching the metal conductor layers on both surfaces of the metal-coated insulating board.

The present invention is particularly useful as a method for producing a printed wiring board having a small diameter through hole having a diameter of 0.5 mm or less and a land width of 0.1 mm or less.

The printed wiring board manufactured by the method of the present invention has a good small-diameter through-hole, because the etching solution does not penetrate into the through hole even in the portion where the land is not substantially formed due to the displacement of the mask. Holes were obtained, and the characteristics of the "buried tenting method" were satisfied. Furthermore, the resolution was high, and it did not change depending on the surface adjustment method, and showed stable resolution.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The photocurable resin layer of the photocurable resin laminate according to the present invention has (a) 10 ^{4 to} 5 at 90 ° C.
Viscosity of × 10 ⁵ poise, (b) thickness of 30 to 80 μm,
And (c) at least one 2,4,5-triarylimidazolyl dimer and at least one p-aminophenyl having an ultraviolet transmittance of 20% or more and less than 40% with respect to an ultraviolet ray having a wavelength of 365 nm. It is characterized in that it contains a ketone and the total content of both is 0.1 to 5.1% by weight.

The photocurable resin layer of the photocurable resin laminate according to the present invention has a viscosity at 90 ° C. of 10 ^{4 to} 5 × 10 ^5.
Must be poise, preferably 5 × 10 ⁴
~ 2 x 10 ⁵ poise. As the viscosity increases, the embedding property of the photocurable resin layer in the small-diameter through-holes decreases,
Even if the laminating conditions are optimized, the superiority to the conventional tenting method becomes small, and if the above upper limit is exceeded, a substantially superior difference cannot be recognized. On the other hand, as the viscosity becomes lower, the photocurable resin layer is more likely to be embedded in the small-diameter through hole. However, in this case, as the photocurable resin laminate, it becomes difficult to sufficiently stably maintain a predetermined uniform thickness of the photocurable resin layer during storage at room temperature. And, if it is less than the above lower limit, the roll end surface of the photocurable resin laminate wound in a roll shape causes a lump of the resin flowing out,
The laminator substantially prevents stable lamination on the substrate.

The thickness of the photocurable resin layer of the photocurable resin laminate according to the present invention must be 30 to 80 μm, preferably 35 to 60 μm. Thickness is 30 μm
If the thickness is thinner, the tenting film of the photo-curable resin layer in the opening of the through-hole tends to swell or break during development, and the depth of the photo-curable resin layer embedded in the through-hole is not sufficient. Reliability is reduced. On the other hand, the thickness is 80 μm
When the thickness is thicker, the transmittance of ultraviolet rays having a wavelength of 365 nm (hereinafter,
It is not preferable because it is difficult to keep the "365 nm ultraviolet ray transmittance") at 20% or more and the resolution is deteriorated.

The photocurable resin layer of the photocurable resin laminate according to the present invention has a 365 nm UV transmittance of 20% or more and 40% or more.
Must be less than%. More preferably 25
% Or more and less than 39% is required. 365 nm
If the ultraviolet ray transmittance is lower than 20%, sufficient tenting film strength cannot be obtained in a portion where there is no land, so that the etching solution permeates. On the other hand, 365 nm
When the ultraviolet ray transmittance is 40% or more, the exposure time becomes long, which is disadvantageous in terms of productivity.

The photocurable resin layer used in the present invention contains a binder made of a vinyl polymer, a photopolymerizable monomer and a photopolymerization initiator as essential components, but if necessary, a dye, a color former,
A plasticizer, a radical polymerization inhibitor, etc. may be included.

As the binder, it is preferable to use one or more monomers from the following two kinds of monomers and copolymerize them so that the acid equivalent becomes 100 to 600. The first monomer is a carboxylic acid having one polymerizable unsaturated group such as a carbon-carbon double bond in the molecule. For example, (meth) acrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, maleic acid half ester and the like. Second
The monomer is a non-acidic monomer having a polymerizable unsaturated group such as a carbon-carbon double bond in the molecule, and developability of the photocurable resin layer, resistance in etching process, and curing film formation. It is chosen to retain various properties such as flexibility. For example, methyl (meth) acrylate, ethyl (meth) acrylate,
Propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth)
Examples include alkyl (meth) acrylates such as 2-hydroxyethyl acrylate, benzyl (meth) acrylate, esters of vinyl alcohol such as vinyl acetate, styrene or a polymerizable styrene derivative, and acrylonitrile.

When the acid equivalent is less than 100, the solubility of the polymer is lowered and it is difficult to obtain a uniform photocurable resin composition,
If the acid equivalent exceeds 600, the dispersibility in an alkaline developing solution is lowered and the developing time is remarkably lengthened.

The weight average molecular weight of the binder is 20,000 to 3
It is preferably in the range of 0,000, and more preferably 40,000 to
200,000. The weight average molecular weight is a value measured by gel permeation chromatography (GPC) using a calibration curve of standard polystyrene. If it is less than 20,000, the strength of the cured resist becomes small, and it is not suitable for the embedded tenting method. When it exceeds 300,000, the viscosity of the photocurable resin composition becomes too high, and the amount of filling in the small-diameter through-holes decreases.

The amount of the binder contained in the photocurable resin layer is preferably 20 to 90% by weight, more preferably 30 to 70% by weight. When it is less than 20% by weight, dispersibility in an alkali developing solution is lowered and the developing time is remarkably lengthened. If it exceeds 90% by weight, the photocuring of the photocurable resin layer becomes insufficient, and the resistance as a resist decreases.

As the photopolymerizable monomer, an unsaturated compound having one or more terminal ethylenically unsaturated groups is used. As examples thereof, 2-hydroxy-3-phenoxypropyl acrylate, phenoxytetraethylene glycol acrylate, β-hydroxypropyl-β′-
(Acroyloxy) propyl phthalate, 1,4-tetramethylene glycol di (meth) acrylate, 1,
6-hexanediol di (meth) acrylate, 1,4
-Cyclohexanediol di (meth) acrylate, octapropylene glycol di (meth) acrylate, glycerol (meth) acrylate, 2-di (p-hydroxyphenyl) propane di (meth) acrylate, glycerol tri (meth) acrylate, trimethylolpropane tri (Meth) acrylate, polyoxypropyl trimethylolpropane tri (meth) acrylate, polyoxyethyl trimethylolpropane tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane Triglycidyl ether tri (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, diallyl phthalate, poly Chi glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, bis (polyethylene glycol (meth) acrylate) polypropylene glycol, 4-n-octyl phenoxy pentaethylene glycol acrylate. Further, examples thereof include urethanization reaction products of a polyvalent isocyanate compound such as hexamethylene diisocyanate and tolylene diisocyanate and a hydroxy acrylate compound such as 2-hydroxypropyl (meth) acrylate.

The amount of the photopolymerizable monomer contained in the photocurable resin layer is preferably in the range of 5 to 60% by weight, more preferably 20 to 55% by weight.

As the initiator contained in the photocurable resin layer, at least one 2,4,5-triarylimidazolyl dimer and at least one p-aminophenyl ketone are essential.

The 2,4,5-triarylimidazolyl dimer is represented by the following chemical formula.

[0028]

Embedded image

The covalent bond connecting two loffin groups is 1
* 1'-, 1.2'-, 1.4'-, 2'-, 2 ...
I'm in the 4'- or 4.4'-position, but 1.2'-
Compounds are preferred. Moreover, the phenyl group may be substituted, for example, 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer, 2- (o-chlorophenyl) -4,5-bis- (m-methoxyphenyl). Imidazolyl dimer, 2- (p-methoxyphenyl) -4.5
-Diphenylimidazolyl dimer and the like are used.

With respect to p-aminophenyl ketone, preferred ones are, for example, p-aminobenzophenone and p-aminobenzophenone.
-Butylaminophenone, p-dimethylaminoacetophenone, p-dimethylaminobenzophenone, p, p '
-Bis (ethylamino) benzophenone, p, p'-bis (dimethylamino) benzophenone [Michler's ketone], p, p'-bis (diethylamino) benzophenone, p, p'-bis (dibutylamino) benzophenone and the like are used.

Both the 2,4,5-triarylimidazolyl dimer and the p-aminophenyl ketone are necessary, and the total addition amount of both is preferably 0.1 to 5.1% by weight. More preferably, it is 1 to 4% by weight. If it is less than 0.1% by weight, the sensitivity is low and practical sensitivity cannot be obtained. If it is more than 5.1% by weight, the ultraviolet ray transmittance becomes small, and it becomes impossible to form a good tenting film when the positions of the mask and the through holes of the substrate are deviated.

Particularly, p-aminophenyl ketone is preferably 0.01 to 0.1% by weight, more preferably 0.02 to 0.8% by weight, from the viewpoint of ultraviolet transmittance. 0.01
If it is less than wt%, photo-curing hardly occurs.
If it exceeds 0.1% by weight, the ultraviolet transmittance becomes small,
It becomes difficult to form a good tenting film when the mask and the through hole of the substrate are misaligned.

The other initiator contained in the photocurable resin layer is not particularly limited, and any known compound can be used.

Specific examples include acridines such as benzyl dimethyl ketal, benzyl diethyl ketal, benzyl dipropyl ketal, benzyl diphenyl ketal, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin phenyl ether, benzophenone and 9-phenyl acridine. Kind,
α, α-dimethoxy-α-morpholino-methylthiophenylacetophenone, 2,4,6-trimethylbenzoylphosphine oxide, phenylglycine, and 1-
There are oxime esters such as phenyl-1,2-propanedione-2-o-benzoyl oxime and ethyl 2,2-dioxo-3-phenylpropionate-2- (o-benzoylcarbonyl) -oxime.

In order to improve the thermal stability and storage stability of the photocurable resin, it is preferable to add a radical polymerization inhibitor to the photocurable resin layer. For example, p-
Methoxyphenol, hydroquinone, pyrogallol,
Naphthylamine, tert-butylcatechol, cuprous chloride, 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis (4-ethyl-6-ter).
t-butylphenol), 2,2′-methylenebis (4
-Methyl-6-tert-butylphenol) and the like.

The photocurable resin layer according to the present invention may contain coloring substances such as dyes and pigments. For example, fuchsin, phthalocyanine green, auramine base, chalcoxide green S, paramagenta, crystal violet, methyl orange, Nile blue 2B, Victoria blue, malachite green, basic blue 20, diamond green and the like.

Further, a color-forming dye which develops color upon irradiation with light may be contained. As a color-forming dye, a combination of a leuco dye and a halogen compound is well known. Examples of leuco dyes include tris (4-dimethylamino-2)
-Methylphenyl) methane [leuco crystal violet], tris (4-dimethylamino-2-methylphenyl) methane [leucomalachite green] and the like. On the other hand, as the halogen compound, amyl bromide, isoamyl bromide, isobutylene bromide, ethylene bromide, diphenylmethyl bromide, benzal bromide, methylene bromide, tribromomethylphenyl sulfone, carbon tetrabromide, tris (2,
3-dibromopropyl) phosphate, trichloroacetamide, amyl iodide, isobutyl iodide, 1,1,
1-trichloro-2,2-bis (p-chlorophenyl)
Examples include ethane and hexachloroethane.

Further, the photocurable resin layer may contain additives such as a plasticizer, if necessary. For example, phthalic acid esters such as diethyl phthalate, o-toluenesulfonic acid amide, p-toluenesulfonic acid amide, tributyl citrate, triethyl citrate, triethyl acetyl citrate, tri-n-propyl acetyl citrate, triacetyl citrate. Examples include -n-butyl and polypropylene glycol.

As the support layer of the photocurable resin laminate, a transparent layer which transmits active light is desirable. For example, polyethylene terephthalate film, polyvinyl alcohol film, polyvinyl chloride film, vinyl chloride copolymer film, polyvinylidene chloride film, vinylidene chloride copolymer film, polymethyl methacrylate copolymer film, polystyrene film, polyacrylonitrile film, Examples thereof include a styrene copolymer film, a polyamide film and a cellulose derivative film.
These films may be stretched if necessary.

In addition to the photocurable resin layer laminated with the support layer, a protective layer is laminated on the surface of the photocurable resin layer, if necessary. An important characteristic of this protective layer is that the protective layer is sufficiently smaller in terms of adhesion to the photocurable resin layer than the support layer and can be easily peeled off. For example, there are a polyethylene film and a polypropylene film. Also, JP-A-59-2
It is also possible to use the film having excellent releasability disclosed in Japanese Patent No. 02457.

In the step of laminating the photocurable resin laminate of the present invention on both sides of the metal-coated insulating plate and embedding it inside the through hole, it extends from the inner peripheral edge of the through hole to the inner wall surface along the inner wall of the through hole. The index n defined as the ratio of the predetermined depth of the photocurable resin layer to the thickness of the metal conductor layer on each surface of the metal-coated insulating plate is shown in FIG. The thickness t of the formed conductor layer 2 and the depth d of the photo-curable resin layer 4 extending from the inner peripheral edge of the through hole 3 onto the inner wall are indices represented by the following equation.

N = d (μm) / t (μm)

The index n is preferably 0.5 or more,
1.1 or more is more preferable.

It is preferable that the index n is larger, since defects are less likely to occur even with a large deviation width, but if the index n is 2 or more, no further increase in the effect is recognized, and the peeling time of the cured resist layer after etching is not increased. It becomes longer and productivity is reduced.
When it is less than 0.5, there is no significant difference from the conventional tenting method.

As the method for laminating the photocurable resin laminate of the present invention on the substrate, a hot roll laminator or a vacuum laminator used in the conventional tenting method can be used. In order to embed it on top, it is necessary to properly set the roll temperature, pressure, laminating speed, etc. of the laminator. Typically,
In order to embed the photocurable resin layer deeper, it is effective to raise the roll temperature and pressure and slow the laminating speed.

In the present invention, the photocurable resin laminate is laminated on both sides of the metal-coated insulating plate by thermocompression bonding using a multi-stage laminator equipped with two or more pairs of upper and lower heating rolls. preferable.

By using a multi-stage laminator,
Embedding the inside of the through-hole so that the index n is 0.5 or more is superior to the one-stage laminator in achieving higher speed.

The exposure is performed on a portion to be left as a wiring and a portion to be left as a coating of the opening of the conductive through hole.
It is carried out using ultraviolet rays such as an ultra-high pressure mercury lamp through a transparent and highly transparent mask.

For development, the unexposed portion is removed by development using an alkaline aqueous solution. As the alkaline aqueous solution, an aqueous solution of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide or the like is used. Most commonly a 0.5 to 3% aqueous sodium carbonate solution is used.

The etching can be carried out by a method suitable for the DFR used, such as acid etching or alkali etching.

Removal of the photocurable resist after etching is
It is peeled off by an alkaline aqueous solution which is stronger than the alkaline aqueous solution used in the development. For example, an aqueous solution of 1 to 5% sodium hydroxide or potassium hydroxide is used.

[0052]

The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the examples.

All "parts" in the following examples are "parts by weight".

Various properties in the examples were measured by the following methods.

1) Viscosity A flow tester CFT-500 manufactured by Shimadzu Corporation was used.

2) Ultraviolet transmittance With a UV spectrometer UV-240 manufactured by Shimadzu Corporation, a laminate of a polyethylene terephthalate film and a photocurable resin layer was placed on the measurement side, a polyethylene terephthalate film was placed on the reference side, and the T% mode was used. It was measured.

3) Embedding depth The substrate after development is embedded and hardened with an epoxy resin and polished until a through hole appears, and the length d (see FIG. 1) extending from the substrate surface to the inner wall is measured with an optical microscope. did.

4) Through-hole defect rate The mask is shifted by 30 μm, exposed, developed, etched, and
After the cured resist was peeled off, the presence or absence of corrosion of the copper on the inner wall of the through hole was examined by an optical microscope. The value obtained by dividing the number of corroded through holes by the total number was defined as "through hole defect rate (%)".

Example 1 A solution having the following composition was prepared. 34% methyl ethyl ketone solution (B-1) of a copolymer having a composition of methyl methacrylate / methacrylic acid / acrylic acid 147 parts butyl (weight ratio 65/25/10) and a weight average molecular weight of 77,000. -Nonaethylene glycol diacrylate (M-1) 10 parts-Bis (pentaethylene glycol methacrylate) 26.5 parts Nonapropylene glycol (M-2) -Half-esterified product of phthalic anhydride and 2-hydroxypropyl acrylate Reaction product of propylene oxide and propylene oxide (M-3: OE-A200 manufactured by Nippon Shokubai Kagaku Co., Ltd.) 8 parts Michler's ketone (I-1) 0.08 part 2- (o-chlorophenyl) -4,5-diphenyl 3 parts Imidazolyl dimer (I-2) -Malachite green (D-1) 0.05 part-Leuco crystal violet D-2) 0.5 parts tribromophenylsulfone (D-3) 0.5 parts Methyl ethyl ketone (MEK) 14.2 parts

A solution having the above composition was uniformly applied to a polyethylene terephthalate film having a thickness of 25 μm using a bar coater and dried in a dryer at 90 ° C. for 5 minutes to form a photocurable resin layer. The thickness of the photocurable resin layer was 50 μm. 365 nm of this photocurable resin layer
The ultraviolet transmittance was 22%.

A 30 μm polyethylene film was laminated on the surface of the photocurable resin layer on which the polyethylene terephthalate film was not laminated to obtain a photocurable resin laminate.

While peeling off the polyethylene of the photocurable resin laminate, the photocurable resin layer was placed on a copper-clad laminate to form a two-stage hot roll laminator (“AL-70” manufactured by Asahi Kasei Kogyo Co., Ltd.).
0 ") at 120/160 ° C. Pressurizing using an air cylinder with an inner diameter of 4 cm, the air pressure applied to the air cylinder is 6.8 kg / cm ² gauge,
The laminating speed was 1.0 m / min. Also, the copper-clad laminate used had a thickness of 1.6 mm, and a glass fiber epoxy base material was laminated with 18 μm copper foil on both sides to have a width of 35 c.
600 through holes having a diameter of 0.35 mm were made in a substrate having a length of 33 cm, and about 25 μm of copper was further deposited by plating to achieve conduction on both sides.

On the photo-curable resin layer, a negative film made by aligning a circular conductive portion having a diameter of 0.4 mm with the position of the through hole was placed with a displacement of 30 μm from the center of the through hole,
Ultra high pressure mercury lamp (HMW-201K, manufactured by Oak Manufacturing Co., Ltd.)
B) exposed at 80 mJ / cm ² .

Subsequently, the polyethylene terephthalate film was peeled off, and a 1% sodium carbonate aqueous solution at 30 ° C. was sprayed for 60 seconds to dissolve and remove the unexposed portion. Further, a cupric chloride solution at 50 ° C. was sprayed for about 115 seconds to etch the copper in the resist-free portion. Finally, a 3% aqueous sodium hydroxide solution at 50 ° C. was sprayed for 80 seconds.

In the printed wiring board of this example obtained as described above, the inner wall of the through hole was not corroded in all the holes, and the defective rate of the through hole was 0%.

Separately, a copper-clad laminate without through-holes was prepared, one for baffle smoothing (3M HD flap brush # 600 / # 600 two stations) and the other for jet scrub smoothing ( Abrasive grains: Sakurandom R # 220, abrasive grain concentration: 20%, spray pressure: 2 kg / cm ² ).
Laminate the photocurable resin laminate on each substrate,
Exposure was carried out through a 21-step step tablet (manufactured by Kodak Co.) and a line pattern having the same width in the exposed and unexposed portions (80 mJ / cm ² ). After development, when the sensitivity and resolution of the photocurable resin laminate were examined, the results of the substrate having the baffle surface and the substrate having the jet scrub surface were the same, that is, 8 steps and 60 μm, respectively.

[Examples 2 to 8 and Comparative Examples 1 to 8] The results obtained by using the compositions shown in Tables 1 and 2 in the same manner as in Example 1 are also shown in Tables 1 and 2. In Comparative Examples 1 and 2, the through hole defect rate was small, but the resolution was 60.
It was worse than μm, and there was a variation in resolution due to the surface adjusting method, so that sufficient performance was not obtained.

The composition abbreviations shown in Tables 1 and 2 are as follows:
This is shown in Example 1 and below.

B-2: Methyl methacrylate / methacrylic acid / benzyl methacrylate (weight ratio 60/25/2
A 33% methyl ethyl ketone solution of a copolymer having a composition of 5) and a weight average molecular weight of 60,000 B-3: having a composition of methyl methacrylate / methacrylic acid / styrene (weight ratio 50/25/25) 35% methyl ethyl ketone solution of a copolymer having a weight average molecular weight of 50,000 B-4: Methyl methacrylate / methacrylic acid / butyl acrylate (weight ratio 65/25/10) and a weight average molecular weight of 12 29% methyl ethyl ketone solution of various copolymers M-4: tetrapropylene glycol diacrylate M-5: urethane reaction product of hexamethylene diisocyanate and oligopropylene glycol monomethacrylate M-6: 4-normal octylphenoxypentapropylene glycol acrylate M-7: trimethylolpropane triacryl M-8: Urethane reaction product of hexamethylene diisocyanate with oligopropylene glycol monomethacrylate and ethylene glycol monoacrylate M-9: Phenoxyhexaethylene glycol acrylate I-3: 4,4′-bis (diethylamino) benzophenone I-4 : 2- (p-methoxyphenyl) -4,5-diphenylimidazolyl dimer I-5: benzyl dimethyl ketal I-6: 2,4-diethylthioxanthone I-7: ethyl p-dimethylaminobenzoate

[Comparative Example 9] The same procedure as in Example 1 was carried out using the photocurable resin laminate of Example 1. However,
The laminating speed when laminating the photocurable resin laminate on the substrate was 2.0 m / min, and the embedding depth was changed. The results are shown in Table 2.

[0071]

[Table 1]

[0072]

[Table 2]

[0073]

As described above, according to the method for manufacturing a printed wiring board of the present invention, a good tenting film can be formed even if the positions of the mask and the through holes are deviated, and the through holes for the etching solution can be formed. Since it can be prevented from entering inside and a high resolution can be stably obtained, it can be extremely advantageously used for manufacturing a high-density printed wiring board using a small-diameter through hole in recent years.

[Brief description of drawings]

FIG. 1 is a schematic enlarged cross-sectional view showing a state of a resin layer formed along an inner wall from an inner peripheral edge of a through hole.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating plate 2 Conductor layers formed on both sides of an insulating plate 3 Through holes 4 Photocurable resin layers laminated on both sides of an insulating plate

Claims (3)

[Claims] 1. A method of manufacturing a printed wiring board having a small diameter through hole, comprising: (1) laminating a photocurable resin laminate including a support on both surfaces of a metal-coated insulating plate having a through hole. The photocurable resin layer has (a) 10 ^{4 to} 5 × at 90 ° C.
At least one of 2, 4, 5 having a viscosity of 10 ⁵ poise, (b) a thickness of 30 to 80 μm, and (c) a UV transmittance of 20% or more and less than 40% for UV having a wavelength of 365 nm. Containing a triarylimidazolyl dimer and at least one p-aminophenyl ketone, the total content of both being 0.1 to 5.1% by weight, from the inner peripheral edge of the through hole to the through hole inner wall The depth of the photo-curable resin layer extending along the inner wall surface along with is 0.5 or more, which is expressed by an index n defined as a ratio to the thickness of the metal conductor layer on each surface of the metal-coated insulating plate. (2) The photo-curable resin layer on each surface of the metal-coated insulating plate is exposed to ultraviolet light through a predetermined transparent pattern mask to cover the opening of the through-hole. Forming a latent image, (3) the resin latent The image is developed with a developer to form a cured resin image, and (4) the metal conductor layers on both sides of the metal-coated insulating plate other than the cured resin image as an etching resist are etched. Manufacturing method of printed wiring board. 2. The light-curable resin layer contains 2,4,4.
The amount of 5-triarylimidazolyl dimer is 0.1-5.
% By weight, and the amount of p-aminophenyl ketone is 0.01 to
The manufacturing method for a printed wiring board according to claim 1, wherein the content is 0.1% by weight. 3. In laminating the photocurable resin laminate on both sides of the metal-coated insulating plate, a pair of upper and lower heating rolls are provided.
The method for producing a printed wiring board according to claim 1, wherein the multi-stage laminator having a series or more is used for thermocompression bonding.