JP2560952B2 - Resin composition, copper foil with resin, and method for producing multilayer printed wiring board having blind via hole - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a resin composition for producing a multilayer printed wiring board suitable for high-density mounting, a copper foil with resin, and physical and electrical characteristics using the copper foil. The present invention relates to a method of manufacturing a multilayer printed wiring board having an excellent blind via hole, which is excellent in mass productivity.

[0002]

2. Description of the Related Art As electronic devices have become smaller and more multifunctional,
Currently, printed wiring boards are moving toward higher densities. For example, finer conductor circuits, higher multilayers, through via holes, blind via holes, through via holes and interstitial via holes such as barrier via holes, and small chips. There are high-density mounting by surface mounting of parts.

In order to explain a conventional method for manufacturing a multilayer wiring board having a blind via hole, schematic cross sections of respective steps are shown in FIGS. 13 to 20. As shown in FIG. 13, an inner layer panel 7 on which a copper wiring pattern 6 is preformed by an etching method is prepared, and one or two prepregs 5 are stacked between the outer layer copper foil 1 and the inner layer panel 7. By laying up and hot pressing, a copper clad laminate panel having an inner layer wiring pattern shown in FIG. 14 is obtained.

Next, holes are sequentially formed at predetermined positions by a drill machine to form holes for blind via holes, as shown in FIG. Continued conventional through hole 1
When 0 is set, the result is as shown in FIG.

Hereinafter, conventional electroless copper plating and electrolytic copper plating are carried out to form the plated through holes 11 as shown in FIG.
After the etching resist 12 is formed (FIG. 18), the subsequent etching is as shown in FIG. 19. Finally, the etching resist film is stripped, and as shown in FIG. 20, the blind via hole is formed. A multilayer printed wiring board having is obtained.

In order to form a blind via hole with a drill in this way, it is not possible to stack a plurality of panels one on top of the other like a normal through hole, but it is necessary to drill one by one, which makes it extremely difficult to drill holes. It takes time and the production efficiency is poor. Further, in drilling, in order to control the depth of the tip of the drill, it is necessary to match the moving distance in the drilling direction, generally the Z-axis direction, with the depth of the copper wiring pattern on the surface of the inner layer panel. . However, as mentioned above, a small diameter drill with a small diameter of about 0.1 to 0.5 mm has a large runout, and there are variations in the position of the copper wiring pattern in the Z-axis direction. If it is shallow, it will not reach the copper wiring pattern at the bottom, and it will not be connected in the plating in the subsequent process, causing blind via hole failure. Conversely, if the drilling is too deep, it will contact the copper foil pattern below it and short-circuit. It may be defective.

Further, regardless of the presence or absence of a blind via hole, in a multilayer printed wiring board, when a prepreg is used as an insulating layer between the inner layer panel and the surface copper foil,
There is a drawback that the multilayer printed wiring board becomes thick. In general, in a multilayer printed wiring board, the adhesion between the insulating layer and the surface copper foil, the electric resistance and the surface insulation resistance are insufficient, which may be an obstacle when forming a fine pattern on the surface copper foil. Was there.

[0008]

DISCLOSURE OF THE INVENTION The present invention eliminates the above-mentioned drawbacks of the conventional method, produces a multilayer printed wiring board having a blind via hole which is excellent in physical and electrical characteristics, stable in quality, and excellent in mass productivity. The present invention provides a resin-coated copper foil and a resin composition used in the method and its production.

[0009]

In the resin-coated copper foil of the present invention, a resin composition which is soluble in an alkaline aqueous solution and has fluidity when heated (hereinafter referred to as "resin composition") is used as the copper foil. It can be obtained by forming a roughened surface.

The resin composition used in the present invention comprises a base resin soluble in an alkaline aqueous solution (hereinafter referred to as "base resin"), an adhesive reinforcing agent, an active energy ray curing reaction initiator, and an active energy ray. It is obtained by blending necessary components selected from a curing reaction accelerator and a curing agent.
Further, if necessary, a color pigment, a moisture resistant pigment, an antifoaming agent, a leveling agent, a thixotropic agent, a polymerization inhibitor and an anti-settling agent may be appropriately added to the above resin composition.

The base resin soluble in the aqueous alkaline solution which constitutes the resin composition used in the present invention includes a non-photosensitive resin containing an alkali-soluble group such as a carboxyl group and a phenolic hydroxyl group, and a carboxyl group. , Photo-polymerization of an alkali-soluble group such as a phenolic hydroxyl group, an acryloyl group and / or a methacryloyl group (hereinafter referred to as “(meth) acryloyl group”), an internal olefin, an azide group, a cinnamic acid ester residue or the like. A photosensitive resin or the like containing a photosensitive group that undergoes photodimerization can be used.

Specifically, as the resin having no photosensitivity,
For example, a copolymer of acrylic acid and / or methacrylic acid (hereinafter referred to as “(meth) acrylic acid”) and a (meth) acrylic ester, a vinyl monomer such as styrene, a copolymer of styrene and maleic anhydride. Half ester with alcohol added to S (ATOCHEM's S
MA1440, SMA17352, SMA2625, S
MA3840 and MONSANTO SCRIPSET
540, SCRIPSET550, etc.), styrene and p
-Copolymer with hydroxyphenylmaleimide, polyvinylphenol or its copolymer (Maruzen Petrochemical Co., Ltd., Marin Curry M, Marin Curry MB; Copolymer with methyl methacrylate, Copolymer with hydroxyethyl methacrylate, A copolymer with styrene, a copolymer with phenylmaleimide, etc.), a novolac type phenol resin, a novolac type cresol resin, a ring-opening adduct of an alcoholic hydroxyl group-containing polymer and an acid anhydride, and the like can be used. In order to impart photosensitivity, a polyfunctional monomer can be used in combination with the above resin.

The base resin soluble in the aqueous alkaline solution of the present invention is preferably one having photosensitivity, and the concentration of the photosensitizing group is preferably in the range of 0.1 to 10.0 meq / g, more preferably 0. 0.3 to 8.0 meq / g, particularly preferably 0.5 to 5.0 meq / g.
If the photosensitive group is too small, the photocurability deteriorates, and if it is too large, the storage stability deteriorates.

As the photosensitive resin, for example, epoxy acrylate and / or epoxy methacrylate (hereinafter referred to as "epoxy (meth) acrylate") and a ring-opening adduct of an acid anhydride, and styrene and maleic anhydride are co-polymerized. Unsaturated alcohol-added half ester, (meth) acrylic acid and (meth) acrylic acid ester, copolymers of vinyl monomers such as styrene, and copolymers of styrene and maleic anhydride were added with alcohol. Half ester, copolymer of styrene and p-hydroxyphenylmaleimide, polyvinylphenol or its copolymer, novolac type phenol resin, novolac type cresol resin, ring-opening adduct of alcoholic hydroxyl group-containing polymer and acid anhydride, etc. React the polymer with glycidyl methacrylate Ring-opening adducts, copolymers of styrene and p-hydroxyphenylmaleimide, polyvinylphenol or its copolymers, some of the hydroxyl groups in phenolic hydroxyl group-containing polymers such as novolac type phenol resins and novolac type cresol resins. , A condensation product with a photosensitive group-containing acid chloride such as (meth) acrylic acid chloride or cinnamic acid chloride, or a photosensitive group such as (meth) acrylic acid chloride or cinnamic acid chloride as part of the hydroxyl groups of the alcoholic hydroxyl group-containing polymer. A compound obtained by condensing the contained acid chloride and ring-opening addition of an acid anhydride to the remaining hydroxyl group, or an isocyanate group-containing acrylate or methacrylate (hereinafter referred to as "(meth) acrylate") to a part of the hydroxyl group of the alcoholic hydroxyl group-containing polymer. ) Is added and the acid anhydride is opened at the remaining hydroxyl group. Added, a copolymer of styrene and p-hydroxyphenylmaleimide, polyvinylphenol or its copolymer, a part of the hydroxyl groups in the phenolic hydroxyl group-containing polymer such as novolak type phenol resin, novolak type cresol resin, Addition of isocyanate group-containing (meth) acrylate, addition of isocyanate group-containing (meth) acrylate to some of the hydroxyl groups of epoxy (meth) acrylate, and opening of acid anhydride to all or part of the remaining hydroxyl groups. A ring-added product can be used.

These manufacturing methods are as follows, for example. A half ester obtained by adding an unsaturated alcohol to a copolymer of styrene and maleic anhydride is ATOCHE
M's SMA1000, SMA2000, SMA300
It can be obtained by addition-reacting an unsaturated alcohol such as hydroxyethyl (meth) acrylate with a copolymer of styrene and maleic anhydride such as SCRISET520 manufactured by MONSANTO.

A copolymer of (meth) acrylic acid and a vinyl monomer such as (meth) acrylic acid ester or styrene,
Half ester obtained by adding alcohol to a copolymer of styrene and maleic anhydride, a copolymer of styrene and p-hydroxyphenylmaleimide, polyvinylphenol or a copolymer thereof, a novolac type phenol resin, a novolac type cresol resin, an alcohol In the case of synthesizing a ring-opening adduct obtained by reacting a polymer such as a hydroxyl group-containing polymer and an acid anhydride ring-opening adduct with glycidyl methacrylate, a solvent (for example, ethers such as diglyme, ethyl carbitol acetate, ethyl cellosolve Acetate, isopropyl acetate, etc. esters, methyl ethyl ketone, cyclohexanone, etc. ketones), dissolve the polymer, and use glycidyl methacrylate as it is or dilute it with a solvent while applying hydroquinone, hydroquinone monomer Ethers, radical polymerization inhibitor to 10 to 10,000 ppm (preferably 30~5,000ppm of phenothiazine, more preferably 50 to
2,000 ppm) and the reaction temperature is room temperature to
It can be obtained by reacting in the range of 170 ° C (preferably 40 to 150 ° C, more preferably 60 to 130 ° C). Also,
At that time, it is preferable to add a quaternary ammonium salt such as tetrabutylammonium bromide or trimethylbenzylammonium chloride or a tertiary amine such as triethylamine as a catalyst. When ring-opening addition of epoxy group of glycidyl methacrylate to alkali-soluble group such as carboxyl group and phenolic hydroxyl group in polymer, react so that a suitable acid value is obtained by leaving a part of alkali-soluble group. Thus, the obtained product can be used as it is in the present invention. When the acid value becomes too small and the alkali solubility decreases, the secondary hydroxyl group produced in the above reaction is further subjected to ring-opening addition of an acid anhydride to increase the acid value to improve the solubility. It can be used in the invention.

A part of the hydroxyl group in the phenolic hydroxyl group-containing polymer such as a copolymer of styrene and p-hydroxyphenylmaleimide, polyvinylphenol or its copolymer, novolac type phenol resin, novolac type cresol resin, ) Condensates with photosensitive group-containing acid chlorides such as acrylic acid chloride and cinnamic acid chloride are solvents (methylene chloride, chloroform, toluene and other water immiscible solvents, or acetone, diglyme,
You can use any solvent that is miscible with water, such as ethyl carbitol acetate), dissolve the polymer, add bases such as sodium hydroxide, potassium hydroxide, calcium hydroxide, and triethylamine, and add acid group-containing acid chloride. It is usually obtained by reacting at 0 to 100 ° C (preferably 0 to 50 ° C, more preferably 0 to 30 ° C). As a catalyst, a quaternary ammonium salt, a tertiary amine, a phosphoric ester, a phosphite, or the like may be used. When using a solvent that is immiscible with water and using an inorganic base,
The reaction may be terminated quickly by adding water to the system. For purification, when a solvent immiscible with water is used, the reaction solution is washed with an acidic aqueous solution and then repeatedly washed with water to dehydrate, filter and remove the solvent. If necessary, reprecipitation purification is performed. When a water-miscible solvent is used, the reaction solution is mixed with an appropriate amount of water to precipitate the product as a solid, which is repeatedly washed with water and then dried. When condensing the phenolic hydroxyl group, which is an alkali-soluble group in the polymer, with an acid chloride group, an appropriate acid value is obtained while leaving a part of the alkali-soluble group.

The isocyanate group-containing (meth) acrylate is added to a part of the hydroxyl groups of the alcoholic hydroxyl group-containing polymer, and the acid anhydride is ring-opened and added to the remaining hydroxyl groups, which is a diisocyanate (two groups such as isophorone diisocyanate). It is desirable to add a (meth) acrylate having a hydroxyl group such as hydroxyethyl acrylate or hydroxyethyl methacrylate to one isocyanate group). The standard condition is to use a tin compound such as dibutyltin dilaurate as a catalyst,
The reaction is performed at about 0 ° C.

The epoxy resin used in the synthesis of the ring-opening adduct of epoxy (meth) acrylate and acid anhydride is a phenol novolac type or cresol novolac type epoxy resin having a polyvinylphenol skeleton and a molecular weight of 1,00.
It is preferably 0 or more, more preferably 3,000 or more, and most preferably 4,000 or more. When the molecular weight is small, the crosslink density does not increase and the heat resistance is poor.

The (meth) acrylic acid used in the ring-opening addition of the epoxy (meth) acrylate and the acid anhydride must be added to 90% or more of the epoxy group, and the charged amount of the (meth) acrylic acid is the epoxy group. 0.98 to 1.10
An equivalent amount is preferable (more preferably 1.00 to 1.07,
Most preferably 1.01-1.04). When the charged amount of (meth) acrylic acid is small, the epoxy groups remain, and the storage stability of the resulting resin deteriorates. In extreme cases, gelation occurs during acid anhydride modification. Conversely, if the amount is too large, the (meth) acrylic acid remains to cause odor or to lower heat resistance.

In the ring-opening addition of epoxy (meth) acrylate and acid anhydride, it is effective to add 30 to 300 ppm of hydroquinone as a radical polymerization inhibitor. Although phenothiazine can be synthesized by adding about 500 ppm, its storage stability is slightly inferior to hydroquinone. When the reaction is performed while blowing air or nitrogen containing 5% oxygen into the reaction solution, the effect of inhibiting radical polymerization may increase.

In the ring-opening addition of an epoxy (meth) acrylate and an acid anhydride, a quaternary ammonium salt such as tetrabutylammonium bromide as a catalyst is preferably contained in an amount of 0.1 to 5.0% (more preferably 0. 3 to 2.0
%) Is used. If the amount of the catalyst is small, the reaction is slow. If the amount is too large, the catalyst remains in the reaction product and the insulating property is deteriorated.

Acid anhydrides used in the synthesis of ring-opening adducts of epoxy (meth) acrylates and acid anhydrides include succinic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, methylhexahydrophthalic anhydride and the like. It is preferable because it has good alkali solubility and can be dissolved with sodium carbonate. Phthalic anhydride, itaconic anhydride, maleic anhydride and the like are difficult to dissolve with sodium carbonate, but can be dissolved with sodium hydroxide. The acid anhydride is preferably used in the range of 0.2 to 0.95 equivalent of the epoxy group before the reaction. If it is less than 0.2 equivalent, it is difficult to dissolve in an aqueous alkali solution, and if it exceeds 0.95 equivalent, unreacted acid anhydride remains, and the physical properties of the composition such as heat resistance and electric properties are deteriorated, and both are not preferable.

In the ring-opening addition of an epoxy (meth) acrylate and an acid anhydride, a raw material or a reaction product which is sufficiently dissolved, a boiling point of which is higher than the reaction temperature, and which does not have a hydroxyl group can be used as a preferable solvent. Solvents with hydroxyl groups such as butyl cellosolve react with acid anhydrides,
Since it may give a by-product that lowers heat resistance, it is better to avoid using it. For example, ethers such as diglyme, esters such as ethyl carbitol acetate, ethyl cellosolve acetate, isopropyl acetate,
Ketones such as methyl ethyl ketone and cyclohexanone are mentioned as preferable solvents. Aromatic hydrocarbons and the like may be used together to the extent that the solubility of the reaction product is not hindered.

The ring-opening addition of the epoxy (meth) acrylate and the acid anhydride is preferably carried out at a reaction temperature of 60 to 160 ° C, more preferably 70 to 140 ° C, and particularly preferably 80 to 120 ° C. If the reaction temperature is too low, the reaction is slow, and if it is too high, gelation occurs or the storage stability of the reaction product deteriorates. The (meth) acrylate reaction is terminated when the acid value of the reaction solution is analyzed with time and becomes almost zero. The reaction time varies depending on the reaction temperature and the catalyst concentration, but it is usually 4 to 30 hours. The acid anhydride modification reaction is usually 1
~ 8 hours.

The ring-opening addition of an epoxy (meth) acrylate and an acid anhydride consists of a two-step reaction as described above. In the first step reaction, the epoxy group of the epoxy resin reacts with the carboxyl group of (meth) acrylic acid. Then, both are linked by an ester bond, and at the same time, a secondary hydroxyl group is generated. The reaction is exothermic. In the reaction in the latter stage, the secondary hydroxyl group produced previously and the acid anhydride react with each other to form an ester bond with each other, and at the same time, a carboxyl group is produced. The reaction is slightly exothermic.

As described above, many base resins soluble in an aqueous alkaline solution can be used, and they can be used in combination, but they are excellent in heat resistance and electric characteristics,
And a novolac type epoxy (meth) acrylate having a carboxyl group is more preferable because it is soluble in both a solvent and an alkaline aqueous solution, and as is well known, active energy rays such as electron beam and ultraviolet ray,
Alternatively, it can be easily cured by means such as heating.

The base resin soluble in an aqueous alkaline solution which constitutes the resin composition used in the present invention has a molecular weight (styrene-equivalent weight average molecular weight by gel permeation chromatography. The same applies hereinafter) of 1,000 to 20.
The range of 10,000 is preferable, and 2,000 is more preferable.
0 to 100,000, most preferably 3,000 to 5
It is 0000. If the molecular weight is too small, heat resistance, water resistance and the like will be poor, and fluidity will be too large. If the molecular weight is too high, the alkali solubility will be poor, which is not preferable.

The base resin soluble in the alkaline aqueous solution which constitutes the resin composition used in the present invention has an acid value of 0.
The range of 2 to 10.0 meq / g is preferable, the range of 0.4 to 5.0 meq / g is more preferable, and the range of 0.
It is 6 to 1.0 meq / g. If the acid value is too small, the alkali solubility will be poor, and if it is too large, the water resistance will be poor.

In the present invention, a photoreactive oligomer and / or a thermosetting resin can be added as an adhesion reinforcing agent to the resin composition soluble in an alkaline aqueous solution for improving the adhesion. As the photoreactive oligomer, polyether type, polyester type, unsaturated polyester type, urethane type, epoxy type, polyester / urethane type, polyacetal type, polybutadiene type and the like can be used. 2-Ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate as the monofunctional oligomer, urethane acrylate, 1,3-butanediol diacrylate as the bifunctional oligomer,
1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, polyethylene glycol 400 diacrylate, hydroxypivalic acid ester neopentyl glycol diacrylate, and a polyfunctional oligomer Trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, triallyl isocyanurate and the like can be used.
As the thermosetting resin, acrylic resin, urethane resin, epoxy resin, polyester resin, polyether resin, alkyd resin, polyvinyl chloride resin, fluororesin, silicone resin, vinyl acetate resin, polyvinyl alcohol and the like can be used.

Urethane acrylates and brominated carbonate oligomers are particularly preferable as the resin exhibiting characteristics when added to a base resin soluble in an aqueous alkaline solution. The urethane acrylate has a function of particularly enhancing the adhesion between the surface copper foil and the resin layer, and as the acrylate, a non-yellowing / medium-hard type urethane acrylate is preferable, and Aronix manufactured by Toagosei Kagaku Kogyo Co., Ltd. M-1
100, Aronix M-1600, Aronix M-
1700 and the like. The above urethane acrylates may be used alone or in combination. The compounding amount is preferably 20 to 120 parts by weight with respect to 100 parts by weight of the solid content of the base resin. If it exceeds 120 parts by weight, the solubility in the aqueous alkali solution becomes poor, and resin residues are likely to be generated. If there is resin residue when conducting the conductive pattern on the inner layer panel and the surface copper foil, sufficient conduction cannot be obtained, while if less than 20 parts by weight, sufficient adhesion between the surface copper foil and the resin layer is achieved. It is difficult to obtain strength.

Further, the brominated carbonate oligomer is effective in flame retardancy and the like. Examples of the oligomer include Fireguard 7000, Fireguard 7500, Fireguard 8100, Fireguard 8500 and the like manufactured by Teijin Chemicals Ltd. The compounding amount is preferably 10 to 60 parts by weight with respect to 100 parts by weight of the solid content of the base resin. When it exceeds 60 parts by weight, the withstand voltage between the conductor pattern of the inner layer panel and the surface copper foil deteriorates, and when it is less than 10 parts by weight, the flame retardancy of the resin layer is insufficient and the adhesion strength becomes low.

A preferred example of the resin composition used for the resin-coated copper foil in the present invention is, as a base resin soluble in an alkaline aqueous solution, for example, 100 parts by weight of a solid content of a novolac type epoxy (meth) acrylate having the above-mentioned carboxyl group. On the other hand, 20 to 120 parts by weight of urethane acrylate as a reinforcing agent for adhesion and 20 to 20 fillers
0 parts by weight, 10 to 200 parts by weight of a solvent and 1 to 10 parts by weight of peroxide as a curing agent are prepared, and if necessary, an active energy ray curing reaction initiator of 0.
5 to 10 parts by weight, active energy ray curing reaction sensitizer 0.
A composition added with 5 to 10 parts by weight is included.

As another example of the resin composition used for the resin-coated copper foil in the present invention, as the base resin soluble in an alkaline aqueous solution, for example, the above-mentioned novolac type epoxy (meth) acrylate solid content of 100 weight% is contained. 20 to 60 parts by weight of urethane acrylate and 10 to 60 parts by weight of brominated carbonate oligomer, 20 to 200 parts by weight of filler, 10 to 200 parts by weight of solvent, and 1 to 10 parts of peroxide as a curing agent. It is obtained by mixing 10 parts by weight, and if necessary, 0.5 to 0.5% of active energy ray curing reaction initiator.
10 parts by weight, active energy ray curing reaction sensitizer 0.5 to
A composition added with 10 parts by weight is included.

As the filler, talc, barium sulfate, clay or the like may be used alone or in a mixture, and those containing a small amount of Aerosil added thereto may be used. However, since the adhesive strength to copper foil is high and the insulation resistance is high. A calcined clay treated with a silane coupling agent is preferred. The blending amount is preferably 20 to 200 parts by weight with respect to 100 parts by weight of the solid content of the base resin. If it is less than 20 parts by weight, the resin will flow too much when the inner layer panel and the surface copper foil are pressed or laminated through the resin composition, and the thickness of the resin layer between the inner layer copper foil and the surface copper foil will be reduced. Could not be secured, resulting in poor insulation,
If it exceeds 200 parts by weight, the fluidity at the time of coating on the copper foil cannot be obtained, and it becomes difficult to dissolve the resin layer for forming the blind via hole.

Benzoin ether type benzyl, benzoin, benzoin alkyl ether, 1-hydroxycyclohexyl phenyl ketone as a reaction initiator for curing active energy rays such as ultraviolet rays and electron beams, benzyl dialkyl ketal type as a ketal type, and 2,2 type as an acetophenone type. '-Dialicoxyacetophenone, 2-hydroxyacetophenone, pt-butyltrichloroacetophenone, pt-butyldichloroacetophenone,
Benzophenone, benzophenone, 4-chlorobenzophenone, 4,4'-dichlorobenzophenone,
4,4'-bisdimethylaminobenzophenone, methyl o-benzoylbenzoate, 3,3'-dimethyl-4-methoxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, dibenzosuberone, benzyldimethylketal, thioxanthone system As thioxanthone,
2-chlorothioxanthone, 2-alkylthioxanthone, 2,4-dialkylthioxanthone, 2-alkylanthraquinone, 2,2'-dichloro-4-phenoxyacetone and the like can be used. The amount is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the solid content of the base resin.
If the amount is less than 0.5 part by weight, the reaction does not sufficiently start, and if the amount exceeds 10 parts by weight, the resin layer becomes brittle. When used by electron beam irradiation, the reaction initiator may be omitted.

As a sensitizer at the curing reaction of active energy rays such as ultraviolet rays and electron rays, Nisso Cure EPA, EMA, IAMA, EHMA, MABP, E manufactured by Shin Nisso Kako Co., Ltd.
ABP, etc. and Kayacure EPA, D manufactured by Nippon Kayaku Co., Ltd.
ETX, DMBI, etc., Ward Blenkinso
Quantacure EPD, BEA, EOB from p.
DMB or the like, DABA manufactured by Osaka Organic Chemical Industry Co., Ltd., PAA or DAA manufactured by Daito Chemical Co., Ltd. can be used. The amount is 0.5 with respect to 100 parts by weight of the solid content of the base polymer.
-10 parts by weight is preferable. When the amount is less than 0.5 part by weight, the reaction rate of the active energy ray curing does not improve. When the amount exceeds 10 parts by weight, the reaction speeds up and the shelf life is reduced.
When used by electron beam irradiation, the reaction sensitizer may be omitted.

As the curing agent, peroxides can be used, but among them, alkyl peroxides such as dibutyl peroxide, butyl cumyl peroxide, dicumyl peroxide or aryl peroxides are preferable from the viewpoint of storage stability. The amount is preferably 1 to 10 parts by weight based on 100 parts by weight of the solid content of the base polymer.
If the amount is less than 1 part by weight, the curing time is prolonged, and if it exceeds 10 parts by weight, the shelf life is shortened and workability is deteriorated. When performing ultraviolet irradiation, electron beam irradiation, or the like, a curing agent is not necessarily required, but it is preferable to add a curing agent in order to enhance adhesion such as copper foil adhesion stability and solder heat resistance.

As the solvent, a resin composition having a high boiling point such as ethyl carbitol acetate, ethyl cellosolve acetate, diethylene glycol dimethyl ether, butyl cellosolve acetate, etc. is preferable because it is easy to screen print the resin composition, and the amount thereof is solid base resin. The amount is preferably 10 to 200 parts by weight with respect to 100 parts by weight. If it exceeds 200 parts by weight, the coating thickness on the copper foil or inner layer panel becomes insufficient, and if it is less than 10 parts by weight, it becomes difficult to obtain the fluidity necessary for printing on the copper foil or inner layer panel. Not preferable.

When the resin composition is applied by a roll coater, bar coater, comma coater, curtain coater, etc., a low boiling point organic solvent such as methyl ethyl ketone, ethyl acetate, toluene is dried after application to remove the organic solvent from the resin composition. It is more preferable because it can be easily removed.

The above resin composition is used in a method for producing a multilayer printed wiring board having a blind via hole, and the production method is as follows, for example. That is, a base resin soluble in an alkaline aqueous solution, a filler, an adhesive reinforcing agent, an active energy ray curing reaction initiator,
Active energy ray curing reaction sensitizer, a resin composition containing a curing agent as a main component is previously formed by coating on a copper foil, and then pressed or laminated on one side or both sides of an inner layer panel on which a conductor pattern is formed in advance, and a copper By forming an etching resist on the foil and performing selective etching to form fine holes (hereinafter referred to as "via holes") corresponding to a specific conductor pattern of the inner layer insulating panel, the removed via holes After removing the lower resin layer with an alkaline aqueous solution and curing the resin layer, the conductive pattern electrically connects the conductor pattern on the inner layer panel to the outer copper foil, and then the outermost copper layer is removed. A multilayer printed wiring board having a blind via hole can be manufactured by selectively etching a mask to form a predetermined pattern.

The resin composition may be applied and formed on an inner layer panel on which a conductor pattern of copper foil or a conductive paste has been formed in advance, and then copper foil may be laminated. Specifically, it is soluble in an alkaline aqueous solution. One side of the inner layer panel on which a conductor pattern is preliminarily formed of a base resin, a filler, an adhesive reinforcing agent, an active energy ray curing reaction initiator, an active energy ray curing reaction sensitizer, and a resin composition containing a curing agent as a main component. Alternatively, after coating and forming on both sides, an etching resist is formed on the copper foil and selective etching is performed to form a via hole corresponding to a specific conductor pattern of the inner layer insulation panel, and the via hole is removed by etching. After removing the lower resin layer with an alkaline aqueous solution and curing the resin layer, use a conductive material to electrically connect the conductor pattern on the inner layer panel to the copper foil on the outer layer. Is conducted to and can subsequently produced multilayer printed wiring board having a blind via hole by forming a selectively etched to a predetermined pattern of copper foil of the outermost layer.

The types of inner layer panels used in the production of the multilayer printed wiring board having blind via holes of the present invention include paper-phenol laminates, paper-epoxy laminates, glass-epoxy laminates, composite laminates, and glass. -A polyimide laminated plate, a polyester film, a polyimide film, a metal core in which a metal substrate is subjected to an insulation treatment, or the like in which a conductor is formed by wiring can be used.

The resin layer that is soluble in the alkaline aqueous solution and has fluidity when heated, as used in the present invention, is a base resin that is soluble in the alkaline aqueous solution, for example, a novolac type epoxy (meth) having a carboxyl group, as described above. It is obtained by mixing 10 to 200 parts by weight of a solvent, 20 to 200 parts by weight of a filler, and 1 to 10 of a peroxide as a curing agent with respect to 100 parts by weight of an acrylate, and if necessary, urethane acrylate or brominated carbonate. An oligomer is added, and 0.5 to 10 parts by weight of an active energy ray curing reaction initiator and 0.5 to 10 parts by weight of an active energy ray curing reaction sensitizer are added. Whether or not a filler is added or added. Two-layer structure with different heating fluidity, depending on the amount or the molecular weight of the base resin It is preferable to.

The first resin layer having a low resin fluidity during heating is placed on the surface of the copper foil, and the second resin layer having a high resin fluidity during heating is placed on the surface of the inner layer panel. When a resin layer having a layered structure is provided, heating in a step of heating and laminating the whole by pressing or laminating, that is, about 60 to
In the range of 80 ° C., the resin of the resin layer, which has a high fluidity during heating, has flowed out between the conductor patterns of the inner layer panel having the conductor pattern and between the conductor patterns and on the surface of the panel to eliminate voids. On the other hand, the resin in the resin layer, which has a low fluidity during heating, has a small resin flow during heating, so the thickness of the insulating layer between the conductor pattern surface and the copper foil is secured, and the copper on the surface of the inner layer panel is secured. Since the thickness of the resin layer between the wiring pattern and the copper foil of the outer layer is constant, it is possible to manufacture a high-quality multilayer printed wiring board with insulation maintained.

That is, a resin composition containing a base resin soluble in an alkaline aqueous solution, a solvent and a curing agent as main components, with or without a small amount of filler as a second resin layer, and a resin composition containing a filler added thereto. It is preferable that the material has a two-layer structure as the first resin layer, and more specifically, 1 to 10 parts by weight of a curing agent relative to 100 parts by weight of a novolac type epoxy (meth) acrylate having a carboxyl group,
A resin composition containing 10 to 200 parts by weight of a solvent as a main component is used as a first resin layer, and 20 to 200 parts by weight of a filler and 1 to 100 parts by weight of a novolac type epoxy (meth) acrylate having a carboxyl group and a curing agent 1 to Second resin composition containing 10 parts by weight and 10 to 200 parts by weight of solvent as main components
The resin layer may be a two-layer structure, and if necessary, 20 to 120 parts by weight of urethane acrylate, 20 to 60 parts by weight of brominated carbonate oligomer,
0.5 to 10 parts by weight of active energy ray curing reaction initiator,
The resin layer containing 0.5 to 10 parts by weight of the active energy ray curing reaction sensitizer can be exemplified as an example of the present invention.

The fluidity of the resin during heating can be controlled not only by adding the filler as described above, but also by adjusting the molecular weight of the base resin. The preferable molecular weight of the base resin used in the present invention is 1,000 to 200,000 as described above, but it is usually 3
When it exceeds 10,000, the fluidity of the resin upon heating is almost eliminated, and when it is 10,000 to 30,000, the fluidity is slightly generated. When it is less than 10,000, the fluidity is exhibited. The fluidity of the resin during heating may be a combination of the addition amount of the filler and the adjustment of the molecular weight of the base resin.

As the second resin layer having high fluidity when heated in the present invention, it is also possible to use a resin composition containing an epoxy resin as a main component used in a conventional prepreg for a laminated plate in a B-stage state. it can. However, in order to dissolve the blind hole resin layer only with an aqueous alkali solution, a resin composition having a novolac type epoxy (meth) acrylate having a carboxyl group as a base resin is preferable. This is because when the inner layer panel and the copper foil with resin are pressed or laminated, the pressure varies due to the effect of the shape of the conductor pattern on the inner layer panel, and the second resin layer completely flows off from the conductor pattern. Instead, it may remain on the pattern. In this case, when the second resin layer is an epoxy resin in the B stage state, it may be dissolved in an organic solvent but not in an alkaline aqueous solution. On the other hand, in the case of a resin composition containing a novolac type epoxy (meth) acrylate having a carboxyl group as a base polymer, such a problem does not occur because it is soluble in an alkaline aqueous solution.

Here, the fact that the fluidity during heating is large means that heating is performed in the step of laminating the resin side of the resin-coated copper foil on the surface of the inner layer panel and laminating the whole by pressing or laminating, that is, about 60 to 80. In the range of ° C, it means that the resin melts and easily flows into the copper wiring pattern of the inner layer panel to fill the concave portion of the pattern.

The copper foil having a resin layer used in the method for manufacturing a multilayer printed wiring board having a blind via hole of the present invention does not necessarily have a two-layer structure of a first resin layer and a second resin layer. A copper foil having an intermediate property between the first resin layer and the second resin layer, that is, a resin layer that is soluble in a molten alkali aqueous solution and has fluidity when heated, but does not completely flow out. May be used. However, in the two-layer structure, when the inner layer panel and the copper foil having the resin layer are laminated, the thickness of the resin layer between the copper wiring pattern of the panel and the surface copper foil is more uniform and the insulation property is higher. Is maintained and a high quality multilayer printed wiring board can be obtained, which is preferable.

In the method for producing a multilayer wiring board having a blind via hole using a resin-coated copper foil in the present invention, the thickness between the conductor pattern surface of the inner layer panel and the surface copper foil is preferably 20 to 150 μm. . If it is less than 20 μm, insulation resistance and withstand voltage between layers cannot be secured, and
If it exceeds m, the undercut becomes large due to the alkali dissolution at the time of forming the blind via hole in the small diameter hole, and sufficient connection reliability cannot be obtained by the plating of the blind via hole or the conductive paste. In the resin-coated copper foil having the first resin layer and the second resin layer,
The thickness of each of the first resin layer and the second resin layer is 30 to 150 μm, depending on the thickness of the surface copper foil of the inner layer panel.
m and 20-50 μm are preferred.

In the method for producing a multilayer printed wiring board having a blind via hole using the resin-coated copper foil of the present invention, when the resin-coated copper foil is laminated on the inner layer panel,
In order to secure adhesion between the resin layer and the copper wiring pattern on the inner layer panel, the surface of the copper wiring pattern on the inner layer panel is roughened, black oxide treated, brown oxide treated, red oxide treated, etc. It is preferable to set.

In the method for producing a multilayer printed wiring board having a blind via hole of the present invention, it is preferable to heat and pressurize with a metal roll when laminating the resin-coated copper foil with the inner layer panel. According to this method,
Unlike ordinary lamination by press, continuous lamination is possible, and the productivity of the multilayer printed wiring board is significantly improved.

In the method for producing a multilayer printed wiring board having a blind via hole using the resin-coated copper foil of the present invention, when the resin-coated copper foil is laminated on the inner layer panel,
In order to avoid the influence of the variation of the plate thickness and the fluctuation of the roll pressure on the thickness of the resin layer between the inner layer panel and the copper foil, a spacer having a thickness of about 30 to 150 μm is formed in a predetermined portion of the inner layer panel. It is preferable to keep. In that case, it is more desirable to arrange the inner layer panel at both ends thereof so as to be perpendicular to the metal rolls of the laminator. By interposing a spacer,
It is possible to solve the problem that the resin layer flows unilaterally and the thickness of the resin layer varies greatly between left and right and front and back.

In the method for producing a multilayer printed wiring board having a blind via hole using the resin-coated copper foil of the present invention, the resin layer below the blind via hole formed on the surface copper foil can be dissolved by an organic solvent. But,
It is more preferable to use an alkaline aqueous solution from the viewpoint of reliability of via holes and workability. Because, when the resin composition is dissolved in an organic solvent, it is a swelling and dissolution reaction, the boundary of the resin after dissolution becomes not smooth and rough,
Moreover, there is a problem that the organic solvent remains near the boundary.
Therefore, when plating a blind via hole in which resin is dissolved, the effect of residual organic solvent and electroless plating are less likely to deposit at the resin boundary, and pinholes are generated in the plating, and even in blind via holes that can be plated. The residual organic solvent evaporates and causes problems such as voids, bubbles, and blistering, which make the electrical and mechanical connections due to blind via holes between the conductive circuits between layers unstable, and connection reliability cannot be obtained. is there. On the other hand, when dissolving the resin with an aqueous alkali solution, the dissolution rate is high because the alkali-soluble groups such as carboxyl groups and phenolic hydroxyl groups react and dissolve, and the resin is sequentially dissolved from the portion in contact with the aqueous alkali solution, so the resin is The boundary of becomes clear. In addition, if the resin is dissolved in an alkaline aqueous solution and then washed with an acid, the alkaline component does not remain, the deposition of the electroless plating afterwards is good, and defects such as voids, bubbles, and blisters do not occur, so that reliability is improved. A high blind via hole can be formed.

Further, it is further preferable in that a multilayer printed wiring board having a blind via hole can be easily manufactured in the conventional manufacturing process of a printed wiring board without deteriorating the working environment like an organic solvent. In other words, if an alkali-soluble etching resist is used to form via holes for copper foil, the resin layer below the copper foil via holes will dissolve simultaneously with the resist during the film stripping process after copper foil etching. it can. Further, when the alkali development type dry film is used as the resist, it is more preferable that the resin layer under the via hole of the copper foil can be dissolved and removed at the same time as the removal of the resist with the sodium hydroxide aqueous solution for stripping.

When a resin layer having an alkali-soluble group such as a carboxyl group or a phenolic hydroxyl group is dissolved in an aqueous alkali solution, the alkali content that has reacted with the carboxyl group or the phenolic hydroxyl group remains, resulting in corrosion of copper or electrical discharge. It is desirable to carry out acid washing with dilute sulfuric acid or the like after the dissolution, because the characteristics may be deteriorated. If the copper foil pattern of the inner layer panel is blackened, or if the resin is dissolved on the blackened surface of the inner layer panel in the via holes when neutralizing the via holes with an acid, The blackened copper oxide film is dissolved, and the color of copper appears. When the resin remains on the surface of the blackening treatment film, the color of copper cannot be seen, and therefore the quality of the alkali dissolution can be judged by this neutralization treatment.

In the method for producing a multilayer printed wiring board having a blind via hole using the resin-coated copper foil of the present invention, the resin layer is cured by heating, for example, and the temperature is preferably in the range of 80 to 180 ° C. , And more preferably 150 to 170 ° C. 180 ° C by heat curing
If the temperature exceeds 80 ° C., the insulating resin forming the inner layer panel deteriorates, and if the temperature is less than 80 ° C., it may take a long time to cure and insufficient crosslinking may result in insufficient insulation resistance.

When the diameter of the blind via hole becomes small, the resin flows out at the time of heating, and in the portion where much flow occurs, the resin covers the surface of the copper foil for connection of the lower inner layer panel,
Even if the blind via hole is plated, a defect that conduction cannot be obtained occurs. For this reason, UV irradiation or electron beam irradiation is performed when the resin begins to flow due to heating, and active energy rays are applied to the resin below the via hole opened in the copper foil or the part facing the via hole to cure the resin. By advancing the above, it is possible to form a weir for the resin flow and prevent the resin from flowing more than necessary. When a blind via hole is opened by the method of the present invention,
The diameter of the hole formed in the inner resin layer tends to be larger than the diameter of the via hole formed in the surface copper foil,
Inconvenience occurs during through-hole plating in the subsequent process. Therefore, the resin may be intentionally flown in advance by heating at 80 to 120 ° C. for about 5 to 15 minutes, and active energy ray curing may be carried out when the diameter of the via hole and the diameter of the hole of the resin layer become approximately equal.

180 to 300 kV in the case of electron beam irradiation
The condition of 10 to 30 Mrad is good, and the electron beam penetrates the copper foil, so that not only the resin layer around the blind via hole can be hardened but also the resin layer under the 18 to 35 μm copper foil can be hardened. it can. For UV irradiation, a normal UV lamp can be used, and scattered light is preferably used.

In the production of a multilayer printed wiring board having a blind via hole using the resin-coated copper foil of the present invention, the copper foil is etched to form via holes, and the resin layer under the holes is dissolved with an alkaline aqueous solution. As a method for electrically connecting the copper wiring pattern of the exposed inner layer panel and the surface copper foil, electroless plating or / and electrolytic plating, conductive paste of gold, silver, copper, solder or the like is screen-printed. It is possible to use a method such as coating with a dispenser, pin printing, etc. and drying and curing. This conductive paste is cured simultaneously with or separately from the resin layer, but it is preferable to perform it at the same time because the process is simplified.

In the method of manufacturing a multilayer printed wiring board having a blind via hole according to the present invention, when copper is plated in the blind via hole, air bubbles originally present in the blind via hole or chemically generated are removed. Therefore, it is preferable to apply ultrasonic waves intermittently or continuously in one or more steps of degreasing, soft etching, activation treatment, electroless copper plating, or electrolytic copper plating step performed as a pretreatment for plating. .

On the multilayer printed wiring board having a blind via hole obtained as described above, a copper foil with a resin is further laminated, and by repeating this, a multilayer printed wiring having a blind via hole of 6 layers or more. Plates can also be obtained.

[0064]

EXAMPLE A method of manufacturing a resin-coated copper foil and a multilayer printed wiring board having blind holes according to the present invention will be described with reference to the drawings. 1 to 12 are schematic cross-sectional views for explaining a manufacturing process and a structure of a multilayer printed wiring board according to the present invention.

Example 1 (Synthesis of Base Resin) 983 g of cresol novolac type epoxy resin (Epototo YDCN704 manufactured by Tohto Kasei Co., Ltd.) and 742 g of ethyl carbitol acetate were placed in a 3 liter flask and heated to 110 ° C. Dissolves and phenothiazine 1.12 as a radical polymerization inhibitor
g, tetrabutylammonium bromide 1 as a catalyst
After adding 1.21 g, 337 g of acrylic acid was gradually added dropwise over 3 hours while maintaining the temperature at 110 ± 5 ° C. After the 4th hour, the reaction was carried out at 120 ± 5 ° C. for about 8 hours until the acid value decreased from 2.23 to almost 0 while measuring by neutralization titration.
Then, 138 g of succinic anhydride was added, and the reaction was carried out for 3 hours from the time when the succinic anhydride was dissolved while maintaining the temperature at 110 ± 5 ° C. to produce a novolac type epoxy acrylate having a carboxyl group.

(Preparation of First Resin Composition) 590 g of the novolac type epoxy acrylate having a carboxyl group prepared as described above, 280 g of baked clay treated with a silane coupling agent as a filler, and acetophenone-based active energy ray curing reaction 20 g of Irgacure 907 from Ciba Geigy as an initiator and Kayacure EP manufactured by Nippon Kayaku Co., Ltd. as a sensitizer for an active energy ray curing reaction
4 g of A, 8 g of Aerosil, 278 g of urethane acrylate (Aronix M-1700 manufactured by Toagosei Kagaku Kogyo Co., Ltd.) as an adhesive reinforcing agent were added, and 157 g of Fireguard 8500 manufactured by Teijin Chemicals Ltd. was preliminarily charged with about 450 g of methyl ethyl ketone. After being dissolved, 40 g of Park Mill D (dicumyl peroxide) manufactured by NOF CORPORATION was dissolved in 40 g of xylene as a curing agent and then mixed, and then passed through a three-roll three times to pass the first resin. A composition was prepared.

(Preparation of Second Resin Composition) To 590 g of the novolac type epoxy acrylate having a carboxyl group prepared as described above, 20 g of Irgacure 907 manufactured by Ciba-Geigy Co., Ltd. as an active energy reaction initiator and as an active energy reaction sensitizer 4 g of Kayakyu EPA manufactured by Nippon Kayaku Co., Ltd., and urethane acrylate as an adhesive reinforcing agent (Aronix M-17 manufactured by Toagosei Kagaku Kogyo Co., Ltd.)
00) to 278 g and Teijin Kasei Co., Ltd. Fireguard 8500 to 157 g and methyl ethyl ketone about 4
It was added after being dissolved in advance with 50 g, and 45 g of NIPPON YUSHI CO., LTD. Park Mill D as a curing agent was dissolved in 45 g of xylene and then mixed, and then passed through a three-roll three times three times.
The resin composition of was prepared.

(Production of Multilayer Printed Wiring Board) A method for producing a multilayer printed wiring board having a blind via hole using the copper clad insulating sheet of the present invention will be described with reference to the drawings. 1 to 9 are schematic cross-sectional views for explaining a manufacturing process and a structure of a multilayer printed wiring board using the resin-coated copper foil of the present invention.

The first resin composition was coated on the matte surface of a 18 μm matted copper foil with a comma coater, passed through a far infrared ray conveyor at 120 ° C. for 30 seconds and 140 ° C. for 30 seconds, and dried to a resin of 70 μm. Layers were formed.

A second resin composition was similarly applied and dried on the first resin layer to form a resin layer having a thickness of 30 μm, to prepare a resin-coated copper foil 1.

An inner layer panel 7 is prepared in which a copper wiring pattern 6 is provided at a predetermined position by selective etching on a glass epoxy double-sided copper clad plate having a thickness of 35 μm copper foil for the inner layer, and the copper wiring pattern of the inner layer panel 7 is prepared. 6 surface with a solution consisting of 37 g / l of sodium chlorite, 10 g / l of sodium hydroxide, and 20 g / l of trisodium phosphate dodecahydrate.
It was treated at 5 ° C. for 5 minutes, washed thoroughly with water, dried and then blackened.

Next, resin-coated copper foil 4 is laminated on both sides of the inner layer panel 7 (FIG. 1) and laminated by a metal roll at 75 ° C. to form a copper clad laminate panel containing the inner layer panel. Created. Here, since the second resin layer 3 has high fluidity, it flows between the copper wiring patterns 6, and the first resin layer 2 has almost no resin flow, so that the lower copper wiring pattern 6 is formed.
The copper clad laminate panel shown in FIG.

Alkali can be applied to the surface of the copper foil 1 of the copper clad laminate panel except for the places where the via holes 8 of the copper foil of 0.1 to 0.3 mmφ are formed by the screen printing method or the photo method. A solution type etching resist was formed, and the copper in the via holes of the copper foil was etched with a ferric chloride solution. Then, when performing film stripping with a 2 wt% sodium hydroxide solution, the first resin layer 2 in the lower layer of the via hole 8 of the copper foil is simultaneously dissolved and removed, and the copper wiring pattern 6 in the lower layer is removed. Upon exposure, no resin residue was visible.

Subsequently, after washing with water and a 10% sulfuric acid aqueous solution, the portion of the blind via hole where the resin was exposed was irradiated with ultraviolet rays to cure the surface of the resin. Then, after pre-drying at 100 ° C. for 30 minutes and aging at 170 ° C. for 30 minutes to cure the first resin layer 2 and the second resin layer 3, the copper wiring pattern of the inner layer panel as shown in FIG. 6 and the through-hole 10 which requires connection with the surface copper foil 4, are drilled, and the blind via hole and the through-hole are simultaneously plated with the through-hole 11 as shown in FIG. 9, an etching resist 12 was formed, etching and film stripping were performed, and a multilayer printed wiring board having blind via holes was obtained.

The peeling strength between the copper foil and the resin layer of the printed wiring board prepared as described above was 1.6 kg / cm.
was gotten. Solder heat resistance is 260 in 25mm square pattern
There was no abnormality in 3 minutes at ℃. Surface insulation resistance is initially 10 ¹⁴
Ω, and 10 ¹² Ω after moisture resistance (C-96 / 40/95). Regarding the withstand voltage, no abnormality was observed at DC1000V. In addition, the conduction resistance of the blind via hole is 1 cycle with a temperature cycle of 125 ° C for 30 minutes and -65 ° C for 30 minutes as one cycle.
As a result of the 00 cycle test, there was almost no change.

(Example 2) Novolac type epoxy acrylate 10 having a carboxyl group obtained in Example 1
To a mixture of 0 parts by weight and 100 parts by weight of ethyl carbitol acetate, 70 parts by weight of talc containing 1 part by weight of Aerosil as a filler and 3.6 parts by weight of dicumyl peroxide as a curing agent are added. , 18μ
50 μm on the roughened surface of copper foil 4 with m-thick matte treatment
To a thickness (after drying), dried at 80 ° C. for 60 minutes to evaporate the solvent to obtain a first resin layer 2 which is soluble in the solvent and the alkaline aqueous solution and has a small resin fluidity even when heated.

A composition comprising 100 parts by weight of a novolac type epoxy acrylate having a carboxyl group, 100 parts by weight of ethyl carbitol acetate as a solvent, and 3.6 parts by weight of dicumyl peroxide as a curing agent,
Apply 30 μm thickness (after drying) on the first resin layer,
A resin-coated copper foil 4 having a second resin layer 3 which is dried at 0 ° C. for 60 minutes, completely evaporates the solvent, is cooled, and is soluble in the solvent and the alkaline aqueous solution and has high fluidity when heated is prepared. did.

Prepare an inner layer panel 7 in which a copper wiring pattern 6 is provided at a predetermined position by selective etching on a glass epoxy double-sided copper clad plate having a thickness of 35 μm copper foil for the inner layer, and resin is provided on both sides of the inner layer panel 7. Copper foil 4 was overlaid (FIG. 1), laid up, and pressed at 80 ° C. and 25 kg / cm ² for 10 minutes. Here, the second resin layer 3 has a high fluidity so that it flows between the copper wiring patterns 6, and the first resin layer 2 has almost no resin flow, and therefore contacts the lower copper wiring pattern 6 as shown in FIG. A copper clad laminate panel was created.

Alkali-soluble in the surface of the copper foil 1 of the copper clad laminate panel except for the places where the via holes 8 of the copper foil of 0.1 to 0.3 mmφ are formed by the screen printing method or the photo method. A mold etching resist was formed and the copper in the via holes of the copper foil was etched with a ferric chloride solution. Then, when performing film stripping with a 2 wt% sodium hydroxide solution, the first resin layer 2 in the lower layer of the via hole 8 of the copper foil is simultaneously dissolved and removed, and the copper wiring pattern 6 in the lower layer is removed. Exposed.

Subsequently, it was washed with water, washed with a 2% sulfuric acid aqueous solution, pre-dried at 100 ° C. for 30 minutes, and then aged at 150 ° C. for 60 minutes to cure the first resin layer 2 and the second resin layer. As shown in FIG. 5, the through hole 10 which requires connection between the copper wiring pattern 6 of the inner layer panel and the copper foil 1 of the outer layer is drilled, and the blind via hole and the through hole are simultaneously formed as shown in FIG. Through-hole plating 11 was applied, etching resist 12 was formed as shown in FIGS. 7, 8 and 9, and etching and film stripping were performed to obtain a multilayer printed wiring board having blind via holes.

Example 3 70 parts by weight of talc obtained by adding 1 part by weight of Aerosil as a filler to the mixture of 100 parts by weight of the novolac type epoxy acrylate having a carboxyl group obtained in Example 1 and 100 parts by weight of ethyl carbitol acetate. Parts, 3.6 parts by weight of dicumyl peroxide as a curing agent, Irgacure 907 as a reaction initiator for ultraviolet curing
5 parts by weight of Kayacure EPA as an ultraviolet curing sensitizer
2 parts by weight of the composition are coated on a roughened surface of a copper foil 4 having a thickness of 18 μm to a thickness of 110 μm (after drying), dried at 75 ° C. for 30 minutes to evaporate the solvent, A first resin layer 2 was obtained which was soluble in a solvent and an aqueous alkaline solution and had a low resin fluidity even when heated.

100 parts by weight of a novolac type epoxy acrylate having a carboxyl group, 100 parts by weight of ethyl carbitol acetate as a solvent, 3.6 parts by weight of dicumyl peroxide as a curing agent, and 5 parts by weight of Irgacure 907 as a reaction initiator for ultraviolet curing. Part, and a composition obtained by adding 2 parts by weight of Kayacure EPA as an ultraviolet curing sensitizer to a thickness of 30 μm (after drying) on the first resin layer.
The resin-coated copper having the second resin layer 3 which is soluble in the solvent and the alkaline aqueous solution and has a high fluidity at the time of heating, 4 was created.

An inner-layer panel 7 is prepared in which a copper wiring pattern 6 is provided at a predetermined position by selective etching on a glass epoxy double-sided copper clad plate having a thickness of 35 μm copper foil for the inner layer, and the copper wiring pattern of the inner-layer panel 7 is prepared. 6 surface was treated with a solution consisting of 37 g / liter of sodium chlorite, 10 g / liter of sodium hydroxide, and 20 g / liter of trisodium phosphate dodecahydrate at 95 ° C. for 5 minutes, thoroughly washed with water, dried and blackened. Processed.

100 μm on both sides of the inner layer panel 7
A thick cellophane tape is used as a spacer 13 so as to be perpendicular to the axial direction of the metal roll 14 (see FIG. 1).
0), the copper foil 4 with a resin layer was laminated on both surfaces of the inner layer panel (FIGS. 1, 11, and 12), and laminated with a metal roll at a temperature of 75 ° C. and a pressure of 15 kg / cm ² . Here, the second resin layer 3 has a high fluidity so that it flows between the copper wiring patterns 6, and the first resin layer 2 has almost no resin flow, and therefore contacts the lower copper wiring pattern 6 as shown in FIG. A copper clad laminate panel was created. Moreover, since the spacers 13 made of cellophane tape are provided at both ends of the inner layer panel, the resin flows to one side or the other in the laminating direction due to the variation of the left / right balance of the metal roll 14 or the variation of the plate thickness of the inner layer panel. A small amount of resin was formed, and a resin layer having a uniform thickness of 100 ± 10 μm was formed between the inner layer copper foil and the outer layer copper foil.

Alkali-soluble in the surface of the copper foil 1 of the copper-clad laminate panel except the portion where the via hole 8 of the copper foil of 0.1 to 0.3 mmφ is formed by screen printing or photo method. A mold etching resist was formed and the copper in the via holes of the copper foil was etched with a ferric chloride solution (FIG. 3). Then, when performing film peeling with a 2 wt% sodium hydroxide solution, the first resin layer 2 under the via hole 8 of the copper foil is simultaneously dissolved and removed,
The lower copper wiring pattern 6 was exposed (FIG. 4). If the resin is not sufficiently dissolved, it may be washed with a 2 wt% sodium carbonate solution.

Subsequently, washing with running water for 1 minute, washing with a 2% sulfuric acid aqueous solution, and further washing with running water for 1 minute,
After drying, the blind hole is irradiated with irregularly reflected ultraviolet rays to cure the surface of the resin layer, followed by pre-curing at 100 ° C. for 30 minutes and aging at 150 ° C. for 60 minutes.
After curing the resin layer 2 and the second resin layer 3 of FIG.
As shown in FIG. 5, a through hole 10 for connecting the copper wiring pattern 6 of the inner layer panel and the copper foil 1 of the outer layer was drilled.

As shown in FIG. 6, when the blind hole and the through hole are simultaneously plated with the through hole 11,
Degreasing is performed at a high temperature of 70 to 80 ° C so that air bubbles in blind holes are removed as much as possible, and after sufficient water washing, soft etching treatment, water washing, acidification treatment, activation treatment, water washing, stabilization treatment, and water washing are sequentially performed. Then, immerse the panel in the electroless copper plating solution, apply ultrasonic waves for 10 seconds every 1 minute,
Plating was performed for a total of 20 minutes while removing hydrogen gas generated by electroless copper plating, and 0.5 μm plated copper was deposited on the entire surface including blind holes. Subsequently, electrolytic copper plating was performed for 60 minutes to deposit 25 μm of electrolytic copper on the blind holes and the entire surface.

Next, as shown in FIGS. 7, 8 and 9, an etching resist 12 is formed, etching and film stripping are performed, and a blind in which the copper wiring pattern of the inner layer panel and the outer layer copper pattern are electrically connected. A multilayer printed wiring board having four conductor layers having holes was obtained.

Moisture resistance test, solder heat resistance test, and peel strength of surface copper foil of the multilayer printed wiring board having blind holes obtained in the above examples were measured. For the moisture resistance test, a comb pattern with a conductor gap of 0.15 mm was prepared and
Insulation resistance between the copper wiring pattern of the inner layer panel and the outer layer copper pattern before and after 96 hours at 0 ° C and 95% humidity IP
It was measured based on the C B25 standard. As a result, the initial value was 10 ¹³ Ω and 10 ¹¹ Ω after the lapse of time. The solder heat resistance was not abnormal in the solder float test at 260 ° C. for 3 minutes. The peel strength of the surface copper foil was 0.7 kg / cm.

(Examples 4 to 11) Examples 4 to 1 of the present invention
Table 1 shows each component composition of the resin composition used for the first resin layer and the second resin layer of No. 1. The numbers in the table are the blending ratio (parts by weight) of each component.

[0091]

[Table 1]

Ethyl carbitol was mixed with the epoxy acrylate having a carboxyl group obtained in Example 1, and then urethane acrylate (Aronix M-1700 manufactured by Toagosei Kagaku Kogyo Co., Ltd.) was mixed at a mixing ratio shown in Table 1.
Brominated carbonate dissolved in methyl ethyl ketone (Fireguard 8500 manufactured by Teijin Chemicals Ltd.), filler mixed with Aerosil, active energy ray curing reaction initiator (IRGACURE 907 manufactured by Ciba Geigy), active energy ray curing reaction sensitizer ( Nippon Kayaku Co., Ltd. Kayacure EPA or peroxide (Nippon Yushi-Seiyaku Co., Ltd., Park Mill D) was mixed, and then each resin composition was prepared by passing three times with a three-roll mill.

The resin compositions for the first resin layer of Examples 4 to 11 in Table 1 were applied by screen printing on the roughened surface of the copper foil 1 having a thickness of 18 μm and dried at 75 ° C. for 10 minutes. Evaporate the solvent, and apply it by screen printing on top of it,
After drying at 75 ° C. for 10 minutes and evaporating the solvent, a first resin layer 2 having a thickness of 70 to 100 μm, which is soluble in the solvent and the alkaline aqueous solution and has a low resin fluidity even when heated, was obtained.

On the first resin layer described above, Examples 4 to
No. 11 resin composition for the second resin layer is applied by screen printing, dried at 75 ° C. for 10 minutes to completely evaporate the solvent, cooled, soluble in the solvent and the alkaline aqueous solution, and fluidity when heated. The resin-coated copper foil 4 having the second resin layer 3 having a large thickness of 30 μm was prepared.

An inner layer panel 7 is prepared in which a copper wiring pattern 6 is provided at a predetermined position by selective etching on a glass epoxy double-sided copper clad plate having a thickness of 35 μm copper foil for the inner layer, and the conductor pattern 6 of the inner layer panel 7 is prepared. The surface is a solution of 37 g / l sodium chlorite, 10 g / l sodium hydroxide and 20 g / l trisodium phosphate dodecahydrate,
It was treated at 95 ° C. for 5 minutes, washed well with water, dried, and blackened.

Next, the resin-coated copper foil 4 is placed on both sides of the inner layer panel 7 (FIG. 1) and laminated with a metal roll at a temperature of 75 ° C. and an air pressure of ² kg / cm ² to form a laminate. A copper clad laminate panel with a built-in panel was created. Here, since the second resin layer 3 has a large fluidity, the conductor pattern 6
Since there was almost no resin flow in the first resin layer 2 flowing in between, the first resin layer 2 came into contact with the lower conductor pattern 6, and the copper clad laminate panel shown in FIG. 2 was produced.

An alkali-soluble etching resist is formed on the surface of the copper foil 1 of the copper clad laminate panel except the portion where the via hole 8 is to be formed, by a screen printing method or a photo method, and a chloride solution is formed. 2 Copper solution was etched with an iron solution to form a via hole of 0.1 to 0.3 mmφ (FIG. 3). Then, when performing film stripping with a 2 wt% sodium hydroxide solution, the first resin layer 2 in the lower layer of the via hole 8 of the copper foil is simultaneously dissolved and removed, and the copper wiring pattern 6 in the lower layer is removed. It was exposed to form blind via holes (Figure 4). In all cases of Examples 4-11 no resin residue was found.

Subsequently, it was washed with water, washed with a 2% sulfuric acid aqueous solution, and the blind via hole was irradiated with ultraviolet rays of scattered light to cure the resin layer surface in the blind via hole, and then pre-dried at 100 ° C. for 30 minutes. Later, at 170 ℃ 30
After aging for a minute to cure the first resin layer 2 and the second resin layer 3, as shown in FIG. 5, a through which requires connection between the conductor pattern 6 of the inner layer panel and the surface copper foil 1 The hole 10 is drilled, the blind hole and the through hole are simultaneously plated with the through hole 11 as shown in FIG. 6, the etching resist 12 is formed as shown in FIGS. 7, 8 and 9, and the etching and the film peeling are performed. Then, a multilayer printed wiring board having a blind via hole was obtained.

In the above example, the laminate panel was prepared by roll laminating, but at 75 ° C. and 25 kg / cm ² , 10
Similar results were obtained when a copper clad laminate panel was prepared by hot pressing for 1 minute.

Table 2 shows the evaluation results of copper peeling strength, solder heat resistance physical properties, surface insulation resistance, withstand voltage electrical properties, and flame retardancy of each of the printed wiring boards prepared as described above.

[0101]

[Table 2]

[0102]

According to the present invention, physical characteristics, electrical characteristics,
A multilayer printed wiring board having a blind via hole with excellent reliability was obtained. Moreover, since the blind via hole can be easily and collectively formed by etching the copper foil and dissolving the resin with the alkaline aqueous solution,
The productivity is greatly improved compared to the conventional drilling process in which each hole is drilled. Further, regardless of the variation in the depth of the copper wiring pattern of the inner layer panel, the blind hole can be surely provided by dissolving the resin layer up to the copper wiring pattern. The connection failure is eliminated, and there is no short-circuit failure erroneously connected to the copper wiring pattern of the other layer for the inner layer. Furthermore, because the prepreg used between the inner layer panel and the surface copper foil can be reduced,
Since the thickness of the printed wiring board can be reduced, a high-density multilayer printed wiring board can be obtained. Therefore, it is extremely useful because it enables the manufacture of a multilayer printed wiring board which requires blind via holes used for high-density mounting in various electronic devices.

[Brief description of drawings]

FIG. 1 is a view showing an inner layer panel having a copper wiring pattern on its surface and a resin-coated copper foil in a process of manufacturing a multilayer printed wiring board having a blind via hole using the resin-coated copper foil of the present invention before heating and pressure bonding. 3 is a schematic cross-sectional view showing the configuration of FIG.

FIG. 2 is a schematic cross-sectional view showing the configuration of a copper clad laminate panel after being subjected to thermocompression bonding in the same manufacturing process.

FIG. 3 is a schematic cross-sectional view showing the copper clad laminate panel after forming via holes in the copper foil on the surface by etching in the same manufacturing process.

FIG. 4 is a schematic cross-sectional view of the copper clad laminate panel after the resin layer under the copper foil via hole is melted in the same manufacturing process.

FIG. 5 is a schematic cross-sectional view after forming a through hole in the same manufacturing process.

FIG. 6 is a schematic cross-sectional view after a plating process in the same manufacturing process.

FIG. 7 is a schematic cross-sectional view after forming an etching resist in the manufacturing process.

FIG. 8 is a schematic cross-sectional view after unnecessary copper foil is removed by etching in the manufacturing process.

FIG. 9 is a schematic cross-sectional view after removing the etching resist in the same manufacturing process.

FIG. 10 is a schematic perspective view after a spacer is attached to the inner layer panel in the same manufacturing process.

FIG. 11 is a schematic cross-sectional view showing a step of stacking a copper clad insulating sheet on an inner layer panel to which a spacer is attached in the manufacturing process.

FIG. 12 is a schematic perspective view showing a step of laminating with a metal roller in the manufacturing process.

FIG. 13 is a schematic cross-sectional view showing a structure before thermocompression bonding of a copper foil and an inner layer panel having a copper wiring pattern on the surface in a manufacturing process of a conventional multilayer printed wiring board having a blind via hole. There is a figure.

FIG. 14 is a schematic cross-sectional view showing the configuration of a copper-clad laminate panel after being thermocompression bonded in the manufacturing process.

FIG. 15 is a schematic cross-sectional view showing the copper clad laminate panel after forming blind via hole holes by drilling in the same manufacturing process.

FIG. 16 is a schematic cross-sectional view showing the copper clad laminate panel after forming through holes by drilling in the same manufacturing process.

FIG. 17 is a schematic cross-sectional view after a plating process in the manufacturing process.

FIG. 18 is a schematic cross-sectional view after forming an etching resist in the manufacturing process.

FIG. 19 is a schematic cross-sectional view after removing unnecessary copper foil by etching in the manufacturing process.

FIG. 20 is a schematic cross-sectional view after removing the etching resist in the manufacturing process.

[Explanation of symbols]

 1 Copper foil 2 1st resin layer 3 2nd resin layer 4 Copper foil with resin 5 Prepreg 6 Copper wiring pattern 7 Inner layer panel 8 Via hole 9 Blind via hole 10 Through hole 11 Plating through hole 12 Etching resist 13 Spacer 14 Metal roller

Claims (10)

(57) [Claims] 1. A resin-coated copper foil for a printed wiring board, comprising a roughened surface of a copper foil and a layer of a resin composition which is soluble in an alkaline aqueous solution and has fluidity when heated. 2. The resin side of the copper foil with resin according to claim 1 is superposed on the surface of the inner layer panel on which a wiring pattern is preformed by processing a copper clad laminate on one side or both sides, and pressed in a heated state. Or a step of laminating and laminating the whole;
A step of forming a via hole in a copper foil on the surface by selective etching at a position where a blind via hole is formed; a resin layer under the via hole is dissolved with an alkaline aqueous solution to form a blind via hole, and a copper for an inner layer panel is formed. A step of exposing the foil; a step of curing the resin layer; a step of electrically connecting the inner layer copper foil and the surface copper foil by plating through a blind via hole; and a wiring pattern on the surface copper foil. A method of manufacturing a multilayer printed wiring board having a blind via hole, comprising the step of forming. 3. The printed wiring board according to claim 1, wherein the resin composition which is soluble in an alkaline aqueous solution and has fluidity when heated contains a novolac type epoxy acrylate or methacrylate having a carboxyl group as a main component. Copper foil with resin. 4. A resin composition for a printed wiring board, which comprises a novolac type epoxy acrylate or methacrylate having a carboxyl group as a main component, and is soluble in an alkaline aqueous solution to which urethane acrylate is further added and which has fluidity when heated. 5. The resin-coated copper foil for a printed wiring board according to claim 1, wherein the resin composition soluble in an alkaline aqueous solution and having fluidity when heated is the resin composition according to claim 4. 6. A first resin layer, which is soluble in an alkaline aqueous solution and has low fluidity when heated, is provided on the roughened surface of the copper foil, and the first resin layer is soluble in the alkaline aqueous solution and heated on the resin layer. The resin-coated copper foil for a printed wiring board according to claim 1, wherein a second resin layer having high fluidity is provided. 7. The resin side of the copper foil with resin according to claim 6 is laminated on the surface of an inner layer panel on which a wiring pattern is preformed by processing a copper clad laminate on one or both sides, and pressed in a heated state. Or a step of laminating and laminating the whole;
A step of forming a via hole in a copper foil on the surface by selective etching at a position where a blind via hole is formed; a resin layer under the via hole is dissolved with an alkaline aqueous solution to form a blind via hole, and a copper for an inner layer panel is formed. Step of exposing foil; first resin layer and second
The step of curing the resin layer of 1 .; the step of electrically connecting the inner layer copper foil and the surface copper foil by plating through the blind via hole; and the step of forming a wiring pattern on the surface copper foil. A method of manufacturing a multilayer printed wiring board having a blind via hole, comprising: 8. The print according to claim 6, wherein the first resin layer and / or the second resin layer comprises a resin composition containing a novolac type epoxy acrylate or methacrylate having a carboxyl group as a main component. Copper foil with resin for wiring boards. 9. The copper foil with resin for a printed wiring board according to claim 6, wherein the first resin layer and / or the second resin layer comprises the resin composition according to claim 4. 10. The multilayer printed wiring having a blind via hole according to claim 2, wherein the resin layer under the via hole formed in the copper foil on the surface is dissolved with an alkaline aqueous solution and then acid washed. Method of manufacturing a plate.