JP3031602B2 - Hole-filling ink for manufacturing copper through-hole printed wiring board and method of using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hole filling ink used in a process of manufacturing a copper through-hole printed wiring board and a method of using the same.

[0002]

2. Description of the Related Art Conventionally, methods for manufacturing the above-mentioned double-sided printed wiring board are disclosed in Japanese Patent Application Laid-Open Nos.
As disclosed in Japanese Patent Application Laid-Open No. 5-102290, the following steps are generally employed. That is, first, a hole for a through hole is formed at a desired position of the double-sided copper-clad laminate, a conductive plating layer is formed in the hole by a through-hole plating method, and a through hole for electrically connecting the front and back conductor patterns is formed. I do. Next, the through-hole is filled with a solvent-drying type filling ink and the filling ink is cured by evaporating the solvent, or the through-hole is filled with an ultraviolet-curing type filling ink and the hole is filled. The filling ink is cured by ultraviolet rays. Thereafter, a desired pattern is formed on the front and back of the laminate with an acid-resistant ink, and after the acid-resistant ink is cured, the exposed copper portion is cupric chloride,
The double-sided printed circuit board is prepared by etching away with an acidic etching solution such as ferric chloride and further removing the filling ink and the acid-resistant ink with an alkaline aqueous solution.

Various types of solvent-drying or ultraviolet-curing inks for filling holes used in the above-mentioned processing steps have been put to practical use.

[0004] However, the solvent-drying type hole filling ink generally requires a long time for curing and has a large volume shrinkage of 20 to 50% due to evaporation of the solvent contained therein. Of the printed wiring board becomes insufficient and the performance of the printed wiring board is likely to be deteriorated.

On the other hand, the ultraviolet curing type hole filling ink has a small volume shrinkage due to curing, but requires a sufficient exposure amount to complete the ultraviolet curing reaction in the deep part of the through hole, and necessitates long-time exposure. In addition, when removing the cured product from the through-hole, there is a problem that causes trouble when mounting components, such as poor peeling with an alkaline aqueous solution and removability, and a portion of the cured product remaining adhered to the inner wall of the through-hole. Easy to occur.

In order to solve the above-mentioned problem of peeling and removability,
It is conceivable to add a filler such as an extender or a coloring pigment, which is an inert solid powder, to the UV-curable ink for filling the hole. The embedding ink becomes more difficult to cure by blending the above filler. In particular, when a coloring pigment such as titanium oxide is used, since it has substantially no function or effect as an ultraviolet curing type hole filling ink,
It cannot be used as a filling ink. Therefore, the type of inert solid powder that can be actually blended is talc,
It is an extender pigment having ultraviolet transmittance such as fine powder silica, etc., and its compounding amount is also limited. Therefore, it is not easy to remove unnecessary hardened portions by buffing or the like after the hardening process of the hole filling ink, and alkali peeling is performed. It is also difficult to improve the performance.

[0007] For the above reasons, both the solvent-drying type and the ultraviolet-curing type hole-filling inks have the performance as hole-filling inks required to cope with the recent fine patterning of printed circuit boards. It was in a state where improvement could not be achieved sufficiently. The present inventor has made Japanese Patent Application No. Hei.
JP-151359 proposed a hole-filling ink using a thermal polymerization reaction. This thermopolymerization type hole filling ink is characterized in that it can be cured in a short time, has a small volume shrinkage due to evaporation of a solvent or the like, has excellent protection properties for through holes, and can be easily removed by an alkaline aqueous solution. However, this is very difficult to cure by thermal polymerization alone.Thus, due to poor polymerization due to oxygen damage, volume reduction due to volatilization of ink components before completion of thermal polymerization in the thermal polymerization process, and deterioration of the covering function of the edge of the through hole, etc. At present, the protection effect is not perfect.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide excellent polymerizability without polymerization failure due to oxygen damage, no volume shrinkage due to evaporation of volatile components during heating, excellent protection of through holes, and alkali. An object of the present invention is to provide a hole-filling ink for producing a copper through-hole printed wiring board which can be easily removed by an aqueous solution, and a method of using the same. Another object of the present invention is to make it possible to increase the amount of the inert solid powder to be added to the filling ink, and to easily remove unnecessary cured portions by buffing or the like after the curing process of the filling ink. It is an object of the present invention to provide an ink for filling holes.
Still another object of the present invention is to provide a hole-filling ink that enables the incorporation of a coloring pigment such as titanium oxide in an inert solid powder, and that can improve the visibility particularly when inspecting the hole-filling state of a circuit board. Is to do.

[0009]

According to the present invention, a hole filling ink for producing a copper through-hole printed wiring board according to the present invention comprises (A) the following general formula (I) or (II):

[0010]

Embedded image

[0011]

Embedded image

Wherein R ₁ is hydrogen or a methyl group, R ₂ is hydrogen or an alkyl group having 1 to 4 carbon atoms, and Y is 1 to 4 carbon atoms.
Alkylene group or a _{- (C n H 2n O)} P -CH 2 - ( wherein, n an integer of 2 to 6, p is an 1-19 integer.)
Represents a group represented by 1 to 90% by weight of the monoester compound represented by｝, (B) 0.01 to 20% by weight of a thermal polymerization catalyst, and (C) 0.01 to 20% by weight of a photopolymerization catalyst.

The monoester compound represented by the general formula [I] or [II] used as the component (A) of the hole filling ink according to the present invention includes, for example, a polycarboxylic acid and a vinyl unsaturated group. Alcohol monoesters may be mentioned.

As the above polycarboxylic acid , tetrahydric
Lophthalic acid , 3-methyltetrahydrophthalic acid, 4-methyltetrahydrophthalic acid , 3- ethyltetrahydrophthalic acid , 4- ethyltetrahydrophthalic acid , 3- propyltetrahydrophthalic acid , 4- propyltetrahydrophthalic acid , 3- butyltetrahydrophthalic acid Acid, 4-butyltetrahydrophthalic acid, hexahydrophthalic acid, 3-methylhexahydrophthalic acid, 4-methylhexahydrophthalic acid, 3-ethylhexahydrophthalic acid, 4-ethylhexahydrophthalic acid, 3-propylhexa Examples thereof include hydrophthalic acid, 4-propylhexahydrophthalic acid, 3-butylhexahydrophthalic acid, and 4-butylhexahydrophthalic acid. Particularly preferred among these are tetrahydrophthalic acid, 3-methyltetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, hexahydrophthalic acid, 3-methylhexahydrophthalic acid and 4-methylhexahydrophthalic acid.

Examples of the alcohol having a vinyl unsaturated group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
-Examples of vinyl monomers such as hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polybutylene glycol mono (meth) acrylate and polycaprolactone mono (meth) acrylate Can be.

The monoester compound of the component (A) is
Although it can be synthesized by various conventional synthesis methods, it can be easily obtained by a ring-opening addition reaction between the above-mentioned polycarboxylic acid anhydride and a vinyl monomer. The compounding amount of the component (A) is from 1 to 90% by weight based on the entire filling ink. When the amount is less than 1% by weight, the removability of the filling ink with an alkaline aqueous solution is deteriorated. Due to the rise, it is difficult to fill the through-hole with the filling ink. A particularly preferred range for the amount of component (A) is 5 to 50% by weight.

A catalyst capable of initiating thermal radical polymerization is used as the thermal polymerization catalyst which is the component (B) of the pore-filling ink according to the present invention. Required.

Examples of the thermal polymerization catalyst include hydroperoxides such as diisopropylbenzene hydroperoxide, cumene hydroperoxide, t-
Butyl hydroperoxide and dicumyl peroxide of dialkyl peroxides, 2,5-dimethyl-2,5-di- (t-butylperoxy) -hexane, 1,3-bis- (t-butylperoxy) Isopropyl) -benzene, t-butylcumyl peroxide, di-t-butylperoxide, 2,5-dimethyl-2,
5-di- (t-butylperoxy) -hexyne-3 and diacyl peroxides such as isobutyryl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, benzoyl peroxide;
Acetyl peroxide and ketone peroxides such as methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide, acetylacetone peroxide, and t-butyl peroxyvivalate of alkyl peresters, t
-Butylperoxy-2-ethylhexanoate, t-
Butylperoxy-3,5,5-trimethylhexaate, t-butylperoxyacetate, t-butylperoxybenzoate, and diisopropyl peroxydicarbonates such as peroxydicarbonates, di-2-
Ethylhexyl peroxydicarbonate, diisopropylperoxydicarbonate, di-sec-butylperoxydicarbonate, and azo compounds such as azobisisobutyronitrile, azobiscyanovaleronitrile, 1,1′-azobis (cyclohexene-1 -Carbonitrile), 2,2'-azobis {2-methyl-N-
(2-hydroxyethyl) -propionamide} and the like, and these can be used alone or in any combination of two or more kinds.

The compounding amount of the component (B) is 0.01 to 20% by weight based on the whole filling ink,
When the amount is less than the above, the thermal radical polymerizability is remarkably reduced, and when it exceeds 20% by weight, the etching resistance is lowered.

As the photopolymerization initiator, which is the component (C) of the pore-filling ink according to the present invention, an ordinary compound that generates a radical or Lewis acid by a photochemical reaction after irradiation with visible, myopic or ultraviolet rays is used. However, in consideration of workability and the like, those having high spectral sensitivity in the ultraviolet region are preferable.

Compounds that induce a radical polymerization reaction include benzophenones, vicinal ketones such as diacetyl, benzyl, α-pyridyl, and acyloin;
For example, pivaloin, α-pyridoin, and benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, and acetophenones such as 4-phenoxydichloroacetophenone, 4-t-butyl -Dichloroacetophenone, diethoxyacetophenone, and thioxanthones, such as 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone,
Thioxanthone derivatives such as 2,4-dipropylthioxanthone, and anthraquinones such as ethylanthraquinone, benzanthraquinone, diaminoanthraquinone, and camphorquinone, 4,4'-
Bis (dimethylamino) benzophenone, dibenzosuberone, 4,4′-diethylisophthalophenone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, acylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide can be mentioned. Among these, benzophenones, thioxanthone and its derivatives, and anthraquinones are particularly preferred. The compound is
They can be used alone or as a mixture of two or more.

The photopolymerization initiator that induces the cationic polymerization reaction includes aryldiazonium, diarylhalonium, triphenylphosphonium, dialkyl-
PF such as 4-hydroxysulfonium, dialkyl-4-hydroxydiphenylsulfonium, and allene-iron complex
_{^{6 -, As F 6 -,}} BF 4 -, Sb F 6 - can be exemplified salts.

Although it is not activated itself by irradiation with ultraviolet rays, an amine-based photoinitiating assistant which promotes a photopolymerization initiation reaction when used in combination with a photoinitiator can also be used. As such photoinitiating aids, mainly aliphatic and aromatic amines are used, for example, triethylenetetramine, triethanolamine, methyldiethanolamine, triisopropanolamine, n-butylamine,
N-methyldiethanolamine, diethylaminoethyl methacrylate, Michler's ketone, 4,4'-diethylaminophenone, ethyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate (n-butoxy), isoamyl 4-dimethylaminobenzoate, etc. Can be mentioned. Among these, Michler's ketone,
4,4'-diethylaminophenone, ethyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoic acid (n-
Aromatic amines such as butoxy) ethyl and isoamyl 4-dimethylaminobenzoate are preferred.

The compounding amount of the component (C) is 0.01 to 20% by weight based on the whole hole filling ink,
If the amount is less than the above, the surface curability of the hole filling ink at the time of exposure is significantly reduced, and if it exceeds 20% by weight, the etching resistance is reduced.

As the component (D) of the hole filling ink according to the present invention, for example, talc, silica, aluminum hydroxide, titanium oxide, barium sulfate,
Organic polymer fine particles such as kaolin, calcium carbonate, phthalocyanine and the like can be mentioned as polyethylene, nylon, polyester and the like, and an inert solid powder such as Aerosil as a thixotropic agent can be mentioned.

By blending these, the general purpose as a filler, such as improving the filling property and filling state when filling the hole filling ink into the through-holes, is achieved. The mechanical polishing property of the cured product after curing of the hole filling ink is improved, and the alkali releasability of the cured product is improved, and the cured product is removed when the cured material of the hole filling ink is removed from the through hole in the final step. It is completely removed without remaining on the inner wall of the through-hole, and trouble at the time of mounting components is prevented.

If necessary, an inert solid powder which is substantially opaque to ultraviolet rays can be blended as the component (D).

In the conventional ultraviolet-curable ink for filling pores, the incorporation of an inert solid powder reduces the curability of the deep part of the through-hole. Was limited to a small amount. In particular, when a coloring pigment such as titanium oxide is used, the curing of the hole filling ink filled in the through-holes is limited to only the surface layer, and has substantially the function and effect as the ultraviolet curing type hole filling ink. Therefore, it cannot be used as a hole filling ink.

In the present invention, "substantially opaque to ultraviolet light" means that the coating before or after curing of the formed pore-filling ink has extremely low ultraviolet transmittance. Examples of the inert solid powder that is substantially opaque to ultraviolet light include coloring pigments such as titanium oxide, zinc white, zinc sulfide, antimony oxide, carbon black, graphite, and chrome yellow. When these coloring pigments are blended, the visibility at the time of visual inspection of the filled state of the through holes can be improved. For this purpose, titanium oxide which is substantially opaque to ultraviolet rays is preferably used as a white pigment having particularly excellent visibility among the above-mentioned coloring pigments.

The component (D) is blended in the hole-filling ink of the present invention as required, and the amount thereof is not particularly limited, but a preferable range is 5 to the entire hole-filling ink.
When the content is less than 5% by weight, the mechanical polishing property of the cured product is not improved, and when the content exceeds 90% by weight, the filling of the through-hole filling ink into the through holes becomes difficult due to an increase in viscosity.

The resin used as the component (E) of the hole filling ink according to the present invention is a phenol resin, a cresol resin, or a rosin resin having an acid value of 50 to 500. These resins may be used alone or in combination of two or more. Can be used together. Among the above resins, a novolak type phenol resin and a cresol resin are preferable. In addition, resole type resins and other alkylphenol resins are not preferable as this component because they are inferior in the removability with an aqueous alkali solution, but can be used supplementarily.

Examples of the rosin resin include natural resins such as gum rosin, wood rosin, chemically modified hydrogenated rosin, polymerized rosin, rosin modified maleic resin, and rosin modified phenol resin. The softening point of these rosin-based resins is preferably 60 ° C. or higher. If the softening point is lower than 60 ° C., the cured filling ink is softened at the time of etching, and the protective effect of the through-hole is likely to be reduced. Especially softening point of 80
The optimum protection effect is obtained when the temperature is higher than ℃. Further, the acid value must be 50 to 500. When the acid value is less than 50, the removability by an alkaline aqueous solution is reduced. When the acid value is more than 500, acid resistance to an etching solution is reduced, and the protective effect of a through hole during etching is reduced. descend. In this respect, a particularly preferred acid value range is 100 to 400.

The component (E) is blended in the hole-filling ink of the present invention as needed, and by blending the component (E), the removability of the hole-filling ink with an alkaline aqueous solution can be improved. The blending amount is not particularly limited, but is preferably 70% by weight or less based on the whole of the hole filling ink. If the amount exceeds 70% by weight, the viscosity of the hole filling ink is increased to fill the through hole. Filling becomes difficult.

The hole-filling ink according to the present invention may further contain, if necessary, a vinyl monomer other than the component (A). Examples of such unsaturated compounds include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, cellosolve (meth) acrylate, methyl cellosolve (meth) acrylate, and butyl cellosolve (meth).
Acrylate, carbitol (meth) acrylate, methyl carbitol (meth) acrylate, butyl carbitol (meth) acrylate, phenoxyethyl (meth) acrylate, dicyclopentadienyl (meth) acrylate, dicyclopentadienyloxyethyl ( (Meth) acrylate, vinyl acetate, N- vinyl pyrrolide
, (Meth) acrylamide , tetrahydrofurfuryl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polybutylene glycol mono (meth) acrylate, polycaprolactone mono (meth) acrylate, phenyl Monofunctional vinyl monomers such as glycidyl ether (meth) acrylic acid adduct, and polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polybutylene glycol di (meth) acrylate, polycaprolactone di (meth) ) Bifunctional vinyl monomers such as acrylates. The compounding amount of this component is preferably 50% by weight or less based on the whole pore filling ink.
When used in excess of 0% by weight, there is a tendency that the removability with an aqueous alkali solution is reduced.

The ink for filling pores according to the present invention may further include an adhesive agent such as a silane coupling agent, various additives such as an antifoaming agent and a leveling agent, or hydroquinone, hydroquinone monomethyl ether, pyrogallol, and tertiary butyl. Polymerization inhibitors such as catechol and phenothiazine,
In order to further improve the dispersion stability, a surfactant, a polymer dispersant, or the like may be added.

The hole-filling ink according to the present invention comprises the above-mentioned components and additives, for example, a three-roll, ball mill,
It can be prepared by using a sand mill or a mixer alone or in combination and kneading by a known method. The hole filling ink can be pre-cured by a known exposure method, and can be thermally polymerized by a known thermosetting method.

FIGS. 1A to 1E are cross-sectional views of a main part showing a specific example of a method of using the hole filling ink according to the present invention.

As shown in FIG.
Insulating substrate 1 made of polyimide resin, polyester resin, etc., copper-clad laminates with copper foil adhered on both upper and lower surfaces, metal-based insulating substrate or ceramic substrate in which metals such as aluminum and iron are insulated with epoxy resin or the like The insulating substrate 1 made of a material used for a normal printed wiring board includes:
A copper plating layer 3 is formed on both surfaces and on the inner wall of the through hole 2 provided therein by electroless copper plating or a combination of electroless copper plating and electrolytic copper plating.

Next, as shown in FIG. 3B, the hole filling ink 4 according to the present invention is immersed in the through-hole 2 to protect the inner wall thereof from an etching solution, a screen printing filling method, and the like. It is filled by a pin filling method or a roll filling method. Subsequently, this substrate is exposed to light on both sides thereof using a high-pressure mercury lamp, a metal halide lamp, or the like at a light amount of 50 to 2,000 mJ per side, so that the surface is preferably 5 μm.
Pre-curing is carried out at the above thickness, and the composition is heated and polymerized at 80 to 150 ° C. for 5 minutes to 2 hours.

At this time, the filling ink 4 in the through hole 2 has a filling rate of about 90 to 100% of the volume in the through hole 2 without exceeding the thickness of the printed wiring board. For this reason, the hole filling ink 4 on the surface of the copper plating layer 3 is easily removed at a low polishing pressure during mechanical polishing in a later step,
Chipping of the hole filling ink 4 in the copper plating layer 3 and the through hole edge portion 2a does not occur, and the filling rate of the hole filling ink 4 can be maintained at 90 to 100% even by the mechanical polishing.

Next, as shown in FIG. 3C, an etching resist layer 5 is formed in a desired pattern on the surface of the copper plating layer 3 after the mechanical polishing, and for example, an etching resist ink for screen printing is used. Can be When the hole filling ink 4 according to the present invention is used, the flattening of the hole filling ink 4 in the through hole 2 is excellent, so that a desired wiring pattern can be precisely and uniformly formed on the opening of the through hole 2 and its peripheral portion. Can be printed. The etching resist layer 5 can be formed by using a dry film resist, an electrodeposition resist, a liquid resist, or the like in addition to the etching resist ink for screen printing.

Subsequently, as shown in FIG. 3D, in the etching step, the copper exposed portions are removed by etching with an etching solution. As the etching solution, an acidic etching solution such as a ferric chloride solution and a cupric chloride solution is used.

Finally, as shown in FIG. 5E, the etching resist layer 5 and the hole filling ink 4 are dissolved and removed by an aqueous solution of an inorganic alkaline substance such as caustic soda, caustic potash, and sodium metasilicate, that is, an alkaline aqueous solution.
An intended copper through-hole printed wiring board is obtained.

It should be noted that the various conditions, steps, and the like in the above method of use are illustrative, and do not limit the present invention.

[0045]

EXAMPLES The present invention will be specifically described below with reference to Synthesis Examples, Examples and Comparative Examples, but the present invention is not limited to these Examples. All parts and percentages used below are based on weight.

Synthesis Example 1 154 g (1 mol) of hexahydrophthalic anhydride and 2-
116 g (1 mol) of hydroxyethyl acrylate was
Known ring opening in the presence of 0.1 g of N, N-dimethylbenzylamine and 0.1 g of hydroquinone monomethyl ether
The monoester compound (A-
1) was obtained.

Synthesis Example 2 168 g (1 mol) of 4-methylhexahydrophthalic anhydride and 144 g of 2-hydroxypropyl methacrylate
(1 mol) is added to N, N-dimethylbenzylamine 0.1
the presence of g and hydroquinone 0.3 g, was obtained monoester compound (A-2) was reacted in the same manner as in Synthesis Example 1.

[Manufacture of hole-filling inks of Examples 1 to 6 and Comparative Examples 1 to 3] Various components are compounded based on the composition (unit:%) of Examples and Comparative Examples shown in Table 1 below. , And kneaded with a three-roll mill to prepare each of the hole-filling inks of Examples 1 to 6 and Comparative Examples 1 to 3 according to the present invention.

Next, with respect to the filling inks of Examples 1 to 6, the double-sided copper-clad laminate having the through holes formed therein was immersed in the filling ink in accordance with the process shown in FIG. After filling the filling ink, it was taken out, and the hole filling ink adhered to both sides of the laminated board was scraped off with a urethane squeegee. Subsequently, the laminated plate was exposed to light using a high-pressure mercury lamp under the conditions shown in Table 2, and the ink for filling holes was preliminarily cured from both sides, and further thermally polymerized. afterwards,
4-axis double-side polishing machine for compound adhering to laminate surface.
It is removed by buffing using Ishii Notation Co., Ltd., and is acid-resistant ink {“PER-143B-5” manufactured by Ryogo Chemical Industry Co., Ltd.}
Was printed and cured by UV exposure. Then, 50
The exposed copper portion was removed by etching with a cupric chloride etching solution at a temperature of ℃, washed with water, and then sprayed with a 3% aqueous sodium hydroxide solution to remove the hole filling ink and the acid-resistant ink to prepare a double-sided printed wiring board.

On the other hand, with respect to the filling inks of Comparative Examples 1 and 3, the double-sided copper-clad laminate having the through holes formed therein was immersed in the filling ink to fill the through holes according to the process shown in FIG. Take out after filling the ink,
The hole filling ink attached to both sides of the laminate was scraped off with a urethane squeegee. Subsequently, the laminate was exposed to light using a high-pressure mercury lamp under the conditions shown in Table 2, and the filling ink was cured from both sides by photopolymerization. Thereafter, the compound adhering to the surface of the laminate was removed by buffing using a four-axis double-side polishing machine (manufactured by Ishii Notation Co., Ltd.), and acid-resistant ink (“PER-143B-5” manufactured by Ryo Chemical Industry Co., Ltd.). Was printed and cured by UV exposure. Then, salt at 50 ° C
The exposed copper portion was removed by etching with a cupric chloride etching solution, washed with water, and then the above-mentioned filling ink and the acid-resistant ink were removed by spraying a 3% aqueous sodium hydroxide solution to prepare a double-sided printed circuit board.

Further, with respect to the filling ink of Comparative Example 2, the double-sided copper-clad laminate having the through-hole was immersed in the filling ink according to the process shown in FIG. After filling, it was taken out and the hole filling ink attached to both sides of the laminate was scraped off with a urethane squeegee. Subsequently, the laminate was heated under the conditions shown in Table 2, and the hole filling ink was cured by heat polymerization. Thereafter, the compound adhering to the surface of the laminate was removed by buff polishing using a four-axis double-side polishing machine (manufactured by Ishii Notation Co., Ltd.).
3B-5 "} was printed and cured by UV exposure.
Subsequently, the exposed copper portion is removed by etching with a cupric chloride etching solution at 50 ° C., and after washing with water, the above-mentioned hole filling ink and the acid-resistant ink are removed by spraying a 3% aqueous sodium hydroxide solution to remove the double-sided printed wiring board. Created.

[0052]

[Table 1]

[0053]

[Table 2]

Each of the hole filling inks of Examples 1 to 6 and Comparative Examples 1 to 3 was tested for each of the test items of filling rate, abrasiveness, proper etching, and dissolving and removing time. Examples 1 to 6 were generally better than Comparative Examples 1 to 3, especially those containing a large amount of component (D), and those containing component (E) showed excellent test results for all test items. On the other hand, in the comparative example, the UV curable ink filled with the component (D) which is substantially opaque to ultraviolet light is not practical because of poor curing. Those containing a large amount of D) have difficulty in filling rate and proper etching.

The following test was separately performed on the hole filling ink of Comparative Example 3. That is, according to the process shown in FIG. 1, the double-sided copper-clad laminate having the through-hole formed therein is immersed in the above-mentioned filling ink, filled with the filling ink in the through-hole, taken out, and filled with the holes filled on both surfaces of the laminate. The ink was scraped off with a urethane squeegee.
Subsequently, this laminate was pressed using a high-pressure mercury lamp,
Exposure was performed at 000 mJ , and the hole-filling ink was cured by photopolymerization from both sides. Thereafter, the uncured filling ink was removed, and the thickness of the remaining cured portion was measured with a micrometer. The thickness was 6 μm for each surface, and most of the filling ink in the through holes was not cured. There was found.

[0056]

As described above, the ink for filling a hole in a copper through-hole printed wiring board according to the present invention is constituted as described above. Therefore, by employing a curing step comprising pre-curing by ultraviolet rays and subsequent thermal polymerization by heat treatment. Excellent polymerizability due to polymerization failure due to oxygen damage, no volume shrinkage due to evaporation of volatile components during heating, excellent through-hole protection and through-hole edge covering function, and easily removed with alkaline aqueous solution can do.

Further, by blending the inert solid powder into the filling ink according to the present invention, unnecessary cured portions can be easily removed by buffing or the like after the curing step of the filling ink. In addition, the ink for filling the hole, even if a compound that is substantially opaque to ultraviolet light as an inert solid powder, is excellent in curability inside the through hole,
It is possible to mix a coloring pigment such as titanium oxide, and it is extremely effective particularly for improving the visibility at the time of inspecting the filled state of the circuit board.

As a result, a high-density copper through-hole printed wiring board having a line width of 100 to 200 μm, which was conventionally produced only by a high-cost manufacturing method using a dry film resist, can maintain high reliability. In addition, it can be manufactured at low cost, and it is very easy to remove defective products during inspection.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part for sequentially explaining one specific example of a method of using a hole filling ink according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Through-hole 2a Through-hole edge part 3 Copper plating layer 4 Hole filling ink 5 Etching resist layer

Claims (7)

(57) [Claims] (A) The following general formula (I) or (II): Embedded image In the formula, R ₁ is hydrogen or a methyl group, R ₂ is hydrogen or an alkyl group having 1 to 4 carbon atoms, Y is an alkylene group having 1 to 4 carbon atoms, or — (C _n H _2n O) _P —CH ₂ —. (Where n is 2 to
An integer of 6 and p is an integer of 1 to 19. ). Copper through-hole printed wiring containing 1 to 90% by weight of a monoester compound represented by｝, (B) 0.01 to 20% by weight of a thermal polymerization catalyst, and (C) 0.01 to 20% by weight of a photopolymerization catalyst. Filling ink for substrate production. 2. The ink for filling a copper through-hole printed circuit board according to claim 1, which comprises (D) an inert solid powder. 3. The ink of claim 2, wherein the component (D) is an inert solid powder which is substantially opaque to ultraviolet light. 4. The hole-filling ink for producing a copper through-hole printed wiring board according to claim 2, wherein the component (D) is titanium oxide which is substantially opaque to ultraviolet rays. 5. The method according to claim 1, comprising (E) at least one resin compound selected from the group consisting of a phenol resin, a cresol resin, and a rosin resin having an acid value of 50 to 500. Filling ink for copper through-hole printed wiring board manufacturing. 6. The component (E) has a softening point of 60 ° C. or higher and an acid value of 5.
The hole filling ink for producing a copper through-hole printed wiring board according to claim 5, which is a rosin-based resin of 0 to 500. 7. The copper through-hole printed wiring according to claim 1, wherein the step of curing the ink in the through-hole comprises pre-curing by ultraviolet rays and subsequent thermal polymerization by heat treatment. How to use hole filling ink for substrate production.