JPH0715119A - Dry film type solder resist - Google Patents

Abstract

PURPOSE:To provide a dry film type of solder resist high in solder resist pattern formation accuracy and excellent in mass productivity by providing a first specified resin composition on a protective film, from which the said layer can separate, and further providing a second specified resin composition on the layer. CONSTITUTION:A first resin composition 1, which is soluble in alkali and small in fluidity by heating and has active energy ray hardening property, is provided on a protective film 3 from which the layer 1 can separate. And further, on the layer 1 is provided a second layer 2, which is soluble in alkali and large in fluidity by heating and has active energy ray hardening property. A first resin layer 1, 50mum thick is made by applying a first resin composition on, for example, a polyester film 3, and drying it for five minutes in an atmosphere of 80 deg.C. Subsequently, a second resin layer 2, 40mum thick is made by applying second resin composition on the first resin layer 1 and drying it for five minutes in an atmosphere of 80 deg.C, thus a dry film in roll shape is made.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a dry film type solder resist capable of easily filling an insulating resin between conductor circuits. The solder resist according to the present invention is a print having surface smoothness. It is particularly useful when used for producing a wiring board.

[0002]

2. Description of the Related Art As electronic equipment becomes smaller and more multifunctional,
At present, printed wiring boards are moving toward higher density. For example, thinning conductor circuits, increasing the number of layers, reducing the diameter of through holes including interstitial via holes such as blind holes and barrier holes, and surface mounting of small chip parts. High-density mounting, etc.

The following types of conventional solder resists for printed wiring boards are available. Thermosetting solder resist prepared by blending heat-resistant thermosetting resin such as epoxy resin and epoxy melamine resin with thermosetting catalyst such as amine, imidazole, acid anhydride and organic solvent such as butyl cellosolve and butyl carbitol; acrylic ester; A UV-curable solder resist comprising a polymerizable monomer such as methacrylic acid ester and a crosslinking monomer such as epoxy acrylate or urethane acrylate, and a photosensitizer such as benzoin ethyl ether or benzophenone; Liquid solder resist that combines each component contained in the UV curable solder resist.

Further, the ultraviolet curable solder resist is
There are a screen printing solder resist and a dry film type solder resist having a three-layer structure of a photosensitive resin layer containing an acrylic copolymer as a main component sandwiched by a protective film made of a polyester film or polyethylene.

Of the above-mentioned thermosetting solder resists and ultraviolet curing solder resists, the screen printing type is inferior in printing accuracy, and therefore liquid solder resists and dry film solder resists are generally used for high density printed wiring boards. ing.

However, when the dry film type solder resist is used, the conductor circuit on the printed wiring board panel on which the solder resist is to be formed is, for example, 50 to 50.
If the thickness is as thick as 70 μm, it becomes difficult to completely embed the solder resist in the narrow conductor gap. If the solder resist is not completely embedded in the space between the conductors, the solder penetrates under the solder resist during soldering, causing electrical shorts between the conductors and deterioration of insulation between conductors due to poor moisture resistance. It may reach. Therefore, in order to forcibly embed the solder resist in the gap between the conductors, it has been attempted to laminate the dry film type solder resist under vacuum.

However, in vacuum lamination, it is difficult to control the thickness of the solder resist on the conductor circuit, and since the whole is attracted by the vacuum pressure, a flat surface is formed on the conductor circuit having irregularities forming various pattern shapes. It is difficult to form the solder resist layer which has. In addition, the laminating apparatus is large and expensive, and the laminating speed is slow, so that productivity is lowered. Further, in the above dry film type solder resist having a three-layer structure, since a polyester film having a thickness of 16 to 25 μm is usually interposed between the pattern film and the photosensitive resin layer, ultraviolet rays leak from the polyester film during exposure,
It had the drawback of poor resolution.

In the case of the liquid solder resist, it is possible to completely embed the solder resist in the narrow gap between the conductors, but a smooth solder resist resin layer is formed on a printed wiring board panel having a thick conductor circuit. Is difficult. For this reason, there is a drawback that voids are generated between the pattern film and the photosensitive resin layer during exposure, ultraviolet rays leak, and a highly accurate solder resist pattern cannot be obtained.

[0009]

SUMMARY OF THE INVENTION The present invention provides a dry film type solder resist which eliminates the above-mentioned drawbacks of the conventional method and has a high solder resist pattern forming accuracy and excellent mass production processability.

[0010]

The present inventors have completed the present invention as a result of intensive studies to solve the above problems. That is, the present invention provides a layer of a first resin composition which is soluble in alkali, has a low fluidity by heating and has an active energy ray-curable property, on a protective film from which the layer can be peeled, and further on the layer. It is a dry film type solder resist provided with a layer of a second resin composition which is soluble in alkali and has a large fluidity by heating and has an active energy ray curability.

Further, in the present invention, the first resin composition and the second resin composition are acrylic acid and / or methacrylic acid (hereinafter referred to as "(meth) acrylic acid"), (meth) acrylic. A linear polymer composed of an acid ester and styrene, (meth) having a base resin obtained by adding an ethylenically unsaturated compound having a glycidyl group to a part of a carboxyl group derived from acrylic acid as a main component, and a crosslinking agent therefor, A resin composition comprising an active energy ray curing reaction initiator and an active energy ray curing sensitizer, wherein the base resin has a molecular weight of 20,000 to 200,000. The resin composition of 2 is 1,000 to 50,000 and is a dry film type solder resist.

Here, the fact that the fluidity during heating is large means that the second resin composition side of the dry film type solder resist is laminated on the surface of the printed wiring board panel having the conductor circuit pattern on the surface thereof. Heating in the process,
Usually, in the range of 60 to 120 ° C., it means that the second resin composition melts and easily flows into the conductor circuit pattern of the printed wiring board panel, and has a fluidity capable of filling the concave portion of the pattern. Further, the fact that the fluidity during heating is small means that the first resin composition maintains substantially non-fluidity at the heating temperature at which the second resin composition exhibits the above fluidity.

In the dry film type solder resist used in the present invention, the resin compositions constituting the first and second layers are alkali-soluble and have active energy ray curability, and are soluble in an alkaline aqueous solution. Base resin (hereinafter simply referred to as "base resin") as a main component, and preferably a crosslinking agent, an active energy ray curing reaction initiator, an active energy ray curing reaction accelerator, and a curing agent if necessary are added thereto. Obtained. If necessary, a flame retardant, a color pigment, a moisture resistant pigment, a defoaming agent, a leveling agent, a thixotropy imparting agent, a polymerization inhibitor, an anti-settling agent, etc. may be added to the above resin composition as needed.

The fluidity of the first resin composition and the second resin composition used in the dry film type solder resist of the present invention upon heating is controlled by the molecular weight of the base resin, the type of crosslinking agent and the amount of crosslinking agent. it can. That is, the smaller the molecular weight of the base resin, the higher the fluidity of the crosslinking agent before curing, and the greater the amount of the crosslinking agent, the greater the fluidity of the resin composition when heated.

As the base resin, a carboxyl group,
Photopolymerization or photodimerization of alkali-soluble groups such as phenolic hydroxyl groups and acryloyl groups or methacryloyl groups (hereinafter referred to as "(meth) acryloyl groups"), internal olefins, azido groups, cinnamic acid ester residues, etc. A resin having a photosensitive group and curable to active energy rays such as ultraviolet rays and electron beams is preferably used, and the concentration of the photosensitive group is preferably in the range of 0.1 to 10.0 meq / g, and more preferably Is 0.3 to 8.0 meq / g,
Particularly preferably, it is 0.5 to 5.0 meq / g. If the concentration of the photosensitive group is too low, the curability of active energy rays deteriorates, and if it is too high, the storage stability deteriorates.

Examples of the resin having active energy ray curability include epoxy acrylate and / or methacrylate (hereinafter "acrylate and / or methacrylate" is referred to as "(meth) acrylate").
And acid anhydride ring-opening adducts, half esters obtained by adding an unsaturated alcohol to a copolymer of styrene and maleic anhydride, (meth) acrylic acid and (meth) acrylic acid ester, or copolymers of vinyl monomers such as styrene. Polymer, half ester obtained by adding alcohol to copolymer of styrene and maleic anhydride, copolymer of styrene and p-hydroxyphenylmaleimide, polyvinylphenol or copolymer thereof, novolac type phenol resin, novolac type cresol resin, Ring-opening adducts of various polymers such as alcoholic hydroxyl group-containing polymers and acid anhydride ring-opening adducts with glycidyl group-containing unsaturated compounds such as glycidyl (meth) acrylate, styrene and p-hydroxyphenylmaleimide copolymerization Coalesce, polyvinylphenol or its copolymer, novola -Type phenol resin, novolac-type cresol resin, etc., some of the hydroxyl groups in the phenolic hydroxyl group-containing polymer, condensation reaction of a photosensitive group-containing acid chloride such as (meth) acrylic acid chloride, cinnamic acid chloride, alcohol (Meth) acrylic acid chloride, cinnamic acid chloride, and other photosensitive group-containing acid chlorides are condensed with some of the hydroxyl groups of the polymerizable hydroxyl-containing polymer, and the remaining hydroxyl groups are subjected to ring-opening addition of an acid anhydride, alcoholic An isocyanate group-containing (meth) acrylate is added to a part of the hydroxyl groups of the hydroxyl group-containing polymer, and an acid anhydride is ring-opened and added to the remaining hydroxyl groups,
Copolymers of styrene and p-hydroxyphenylmaleimide, polyvinylphenol or its copolymers, novolac-type phenol resins, novolac-type cresol resins, and the like. ) Addition of acrylate, addition of isocyanate group-containing (meth) acrylate to some hydroxyl groups of epoxy (meth) acrylate, and ring-opening addition of acid anhydride to all or some of the remaining hydroxyl groups, etc. Is mentioned.

Among the resins having active energy ray curability, a (meth) acrylic resin having photosensitivity and soluble in an alkaline aqueous solution, particularly a copolymer of (meth) acrylic acid ester, styrene and (meth) acrylic acid is used. The polymer obtained by ring-opening addition of an ethylenically unsaturated compound containing a glycidyl group, for example, glycidyl (meth) acrylate, has excellent alkali solubility, and has excellent insulation resistance and heat resistance when used as a resist. It is preferable because it exists.

When the epoxy group of glycidyl (meth) acrylate is added to the carboxyl group in the copolymer by ring-opening addition, a part of the carboxyl group is left to have an appropriate acid value, so that the polymer obtained is alkaline. Becomes soluble. When the acid value becomes too small and the alkali solubility decreases, the acid value can be increased by ring-opening addition of an acid anhydride to the secondary hydroxyl group produced by the ring-opening addition reaction.

The base resin may be blended with a resin containing an alkali-soluble group such as a carboxyl group or a phenolic hydroxyl group and having no active energy ray-curing property.

Examples of the resin having no active energy ray curability include (meth) acrylic acid, (meth) acrylic acid ester, copolymers with vinyl monomers such as styrene, and copolymers with styrene and maleic anhydride. A half ester obtained by adding alcohol to SMA1440, SMA17352, SMA262 of ATOCHEM.
5, SMA3840 and SCRIP of MONSANTO
SET540, SCRIPSET550, etc.), a copolymer of styrene and p-hydroxyphenylmaleimide,
Polyvinylphenol (Maruzen Petrochemical Co., Ltd. Marca Linker M, Marca Linker MB, etc.) or a copolymer of polyvinyl phenol and methylmethacrylate, hydroxyethylmethacrylate, styrene, phenylmaleimide, etc., novolac type phenol resin, novolac type Examples thereof include cresol resins, alcoholic hydroxyl group-containing polymers and acid anhydride ring-opening adducts.

As the base resin, (meth) acrylic acid 15 to 40% by weight, styrene 5 to 20% by weight, (meth)
A linear polymer having 40 to 75% by weight as an acrylic ester as a constituent component, and 30 to 70% of the carboxyl group derived from (meth) acrylic acid in the first resin composition.
It is preferable that 20 to 40% of the second resin composition is modified with an ethylenically unsaturated compound each having a glycidyl group. If it is less than the lower limit, the heat resistance of the resin obtained will be reduced, and if it exceeds the upper limit, the alkali solubility will be poor. As the linear polymer, other vinyl monomers such as acrylonitrile can be copolymerized, if necessary, within a range in which the physical properties of the linear polymer are at least substantially maintained.

If the content of (meth) acrylic acid is more than 40% by weight, the alkali solubility is too high, and if it is less than 15% by weight, the alkali solubility is lowered and the pattern resolution is lowered. If the amount of styrene exceeds 20% by weight, the resin layer becomes hard and cracks easily, and if less than 5% by weight, heat resistance cannot be obtained.
The Tg (glass transition temperature), resin fluidity and alkali solubility can be adjusted by the amount of the (meth) acrylic acid ester, and the above range is the optimum range.

As the (meth) acrylic acid ester, it is preferable to use butyl (meth) acrylate and hydroxyethyl (meth) acrylate or a mixture of these with methyl (meth) acrylate.

The ethylenically unsaturated compound having a glycidyl group is preferably glycidyl methacrylate in the first resin composition and glycidyl (meth) acrylate in the second resin composition.

The base resin constituting the first resin composition used in the present invention has a molecular weight (styrene-equivalent weight average molecular weight by gel permeation chromatography) in the range of 20,000 to 200,000. Preferably, more preferably 40,000 to 150,000
Is. If the molecular weight is too small, the fluidity during heating will be too large, and if it is too large, the alkali solubility will be poor. The base resin that constitutes the second resin composition preferably has a molecular weight of 1,000 to 50,000, and more preferably 5,000 to 30,000. If the molecular weight is too small, the heat resistance, water resistance, etc. will deteriorate, and if it is too large, the fluidity during heating will be too small.

The base resin constituting the resin composition used in the present invention has an acid value of 0.2 to 10.0 meq / g.
Is preferable, and more preferably 0.4 to 5.0 me.
q / g, particularly preferably 0.6 to 3.0 meq / g. If the acid value is too small, the alkali solubility will deteriorate,
If it is too large, the water resistance will be poor.

The resin composition used in the present invention preferably contains a photoreactive compound as a crosslinking agent. As the photoreactive compound, acrylic type, polyether type, polyester type, unsaturated polyester type, urethane type, epoxy type, polyester / urethane type, polyacetal type, polybutadiene type and the like can be used. Examples thereof include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, and 2-hydroxypropyl acrylate as monofunctional compounds; urethane acrylate, 1,3-butanediol diacrylate, and 1,4-difunctional compounds. Butanediol diacrylate,
1,6-hexanediol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, polyethylene glycol diacrylate, hydroxypivalate neopentyl glycol diacrylate; trimethylolpropane triacrylate, pentaerythritol triacrylate as polyfunctional compounds , Dipentaerythritol hexaacrylate, triallyl isocyanurate, etc., or addition products or condensation products thereof.

As the cross-linking agent, urethane acrylate, polypropylene glycol diacrylate and pentaerythritol triacrylate are particularly preferable. Urethane acrylate has a function of enhancing adhesion between the surface copper foil and the resin layer, polypropylene glycol diacrylate has a function of enhancing fluidity of the resin composition after heating, and pentaerythritol triacrylate is a resin. It particularly has the effect of increasing the heat resistance of the composition after curing. It is desirable to add 20 to 120 parts by weight of one or more of the above crosslinking agents to 100 parts by weight of the base resin. When it exceeds 120 parts by weight, the solubility in an alkaline aqueous solution is deteriorated, and a resin residue is likely to occur. 20
If the amount is less than parts by weight, sufficient adhesion strength between the resin composition and the surface conductor circuit cannot be obtained.

In the resin composition used in the present invention, a thermosetting resin can be used as an adhesive reinforcing agent, if desired. Examples of the thermosetting resin include urethane resin, epoxy resin, polyester resin, polyether resin, alkyd resin, polyvinyl chloride resin, fluororesin, silicone resin, vinyl acetate resin and polyvinyl alcohol.

As a reaction initiator for the curing of active energy rays, benzoin ether type benzyl, benzoin, benzoin alkyl ether, 1-hydroxycyclohexyl phenyl ketone; ketal type benzyl dialkyl ketal; acetophenone type 2,2 '.
-Dialicoxyacetophenone, 2-hydroxyacetophenone, pt-butyltrichloroacetophenone,
p-t-butyldichloroacetophenone; benzophenone-based benzophenone, 4-chlorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdimethylaminobenzophenone, methyl o-benzoylbenzoate, 3,3'-dimethyl -4-methoxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, dibenzosuberone, benzyl dimethyl ketal;
Thioxanthone, 2-chlorothioxanthone, 2-alkylthioxanthone, 2,4-
Examples thereof include dialkylthioxanthone, 2-alkylanthraquinone, and 2,2′-dichloro-4-phenoxyacetone, and the compounding amount thereof is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the base resin. If it is less than 0.5 part by weight, the reaction is not sufficiently initiated, and if it exceeds 10 parts by weight, the resin layer becomes brittle.

As the sensitizer at the time of the reaction of curing with active energy rays, Nisso Cure EPA and EM manufactured by Shin Nisso Kako Co., Ltd.
A, IAMA, EHMA, MABP, EABP, etc., Kayacure EPA, DETX, DMBI manufactured by Nippon Kayaku Co., Ltd.
Quanta made by Ward Blenkinsop
cure EPD, BEA, EOB, DMB, DABA made by Osaka Organic Co., Ltd., PAA, D made by Daito Chemical Co., Ltd.
AA etc. are mentioned. The amount of the base resin is 100
0.5 to 10 parts by weight is preferable with respect to parts by weight. 0.5
If it is less than 10 parts by weight, the reaction rate of active energy ray curing does not improve, and if it exceeds 10 parts by weight, the reaction becomes faster and shelf life is shortened. 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 of base resin 1
1 to 10 parts by weight is preferable with respect to 00 parts by weight. If it is less than 1 part by weight, the curing time will be long, and if it exceeds 10 parts by weight, the shelf life will be short and the workability will be poor. A curing agent is not necessarily required when performing ultraviolet irradiation, electron beam irradiation, etc., but it is preferable to add a curing agent in order to improve the adhesion stability with the surface copper foil, the solder heat resistance, and the like.

In order to use the resin composition of the present invention as a solder resist, it is preferable that it has a solder heat resistance of at least 260 ° C. for several tens of seconds in a float test for measuring a solder heat resistance, which will be described later, and constitutes a base resin. The heat resistance of the resin composition can be improved by appropriately selecting the type of monomer to be used and the type and amount of the crosslinking agent.

The first resin composition of the present invention preferably has less tackiness at room temperature. The tackiness is mainly determined by the glass transition point of the base resin, but also depends on the type and amount of the additive. If the surface tackiness is large at room temperature, a protective film is required on the surface of the solder resist during exposure, resulting in poor developability. The ball tack test (JIS Z023
It is preferably 2 or less in 7).

In the dry film type solder resist of the present invention, the thickness of the first resin composition layer applied to the printed wiring board panel is 10 to 100 μm, and the thickness of the second resin composition layer is 20 to 60 μm. However, the optimum combination of thicknesses can be set depending on the required thickness of the solder resist insulating layer and the thickness and area of the conductor circuit.

The protective film used in the present invention is used for protection for laminating the solder resist of the present invention on a printed wiring board panel, and may be of any type as long as the resin composition can be peeled off after lamination. Polyester film, etc. can be used.

[0037]

The function of the dry film type solder resist of the present invention is
The first resin composition has a small resin flow during heating, but the second resin composition
The resin composition of is large. Therefore, in the laminating step, the second resin composition can flow between the conductor circuit patterns of the printed wiring board panel or to the surface of the panel to fill the voids, while the first resin composition has a uniform thickness on the conductor circuit. A resist layer can be formed. Further, unlike the conventional dry film type solder resist, since it is laminated on the printed wiring board panel by heating, it becomes possible to completely fill even a narrow conductor gap. Further, since the surface tackiness is small, the protective film can be peeled off after the laminating, which makes it possible to obtain a highly accurate solder resist pattern when exposed to ultraviolet rays.

[0038]

Example 1 (Synthesis example 1 of base resin) 40 parts by weight of n-butyl methacrylate, 15 parts by weight of methyl methacrylate, 10 parts by weight of styrene, 10 parts by weight of hydroxyethyl methacrylate, 25 parts by weight of methacrylic acid, azobisisobutyl A mixture of 1 part by weight of nitrile was added dropwise to 120 parts by weight of propylene glycol monomethyl ether kept at 80 ° C. in a nitrogen gas atmosphere over 5 hours. afterwards,
After aging for 1 hour, 0.5 more azobisisobutyl nitrile
A carboxyl group-containing methacrylic resin was synthesized by adding parts by weight and aging for 2 hours. Next, while blowing in air, 15 parts by weight of glycidyl methacrylate, 1.5 parts by weight of tetrabutylammonium bromide, and 0.15 parts by weight of hydroquinone as a polymerization inhibitor were added and reacted at a temperature of 80 ° C. for 8 hours to give a molecular weight of 50,000. ~ 7
50,000, acid value 1.2 meq / g, unsaturated equivalent 1.1
A base resin having a carboxyl group of 4 mol / kg was synthesized.

(Synthesis example 2 of base resin) 50 parts by weight of n-butyl methacrylate, 9 parts by weight of hydroxyethyl methacrylate, 9 parts by weight of styrene, 32.
A mixture of 5 parts by weight and 2 parts by weight of azobisisobutylnitrile was added dropwise to 120 parts by weight of propylene glycol monomethyl ether kept at 90 ° C. in a nitrogen gas atmosphere over 5 hours. Thereafter, after aging for 1 hour, 1 part by weight of azobisisobutylnitrile was further added and aging was performed for 2 hours to synthesize a carboxyl group-containing methacrylic resin. Next, while blowing in air, 15 parts by weight of glycidyl methacrylate, 1.5 parts by weight of tetrabutylammonium bromide, and 0.15 parts by weight of hydroquinone as a polymerization inhibitor were added and reacted at a temperature of 80 ° C. for 8 hours to give a molecular weight of 25,000. ~ 30,000, acid value 2.0me
A base resin having a carboxyl group of q / g and an unsaturated equivalent of 1.14 mol / kg was synthesized.

(Preparation of First Resin Composition) 60 parts by weight of the base resin of Synthesis Example 1, 20 parts by weight of pentaerythritol triacrylate (Aronix M-305 manufactured by Toagosei Chemical Industry Co., Ltd.) as a crosslinking agent, and urethane Acrylate (Aronix M- manufactured by Toagosei Chemical Industry Co., Ltd.)
1600) 20 parts by weight, 5 parts by weight of active energy ray curing reaction initiator, 2 parts by weight of active energy ray curing sensitizer, and Fireguard 3000 manufactured by Teijin Chemicals Ltd. as a flame retardant.
30 parts by weight, as a curing agent, 1.5 parts by weight of Park Mill D manufactured by NOF CORPORATION, and 1 part by weight of phthalocyanine green as a pigment were well mixed to prepare a resin composition for the first layer.

(Preparation of Second Resin Composition) 60 parts by weight of the base resin of Synthesis Example 2 and Aronix M- as a crosslinking agent
20 parts by weight of 305, 20 parts by weight of Aronix M-1600, 5 parts by weight of an active energy ray curing reaction initiator, 2 parts by weight of an active energy ray curing sensitizer, 30 parts by weight of Fireguard 3000 as a flame retardant, a curing agent. As a pigment, 1.5 parts by weight of Park Mill D and 1 part by weight of phthalocyanine green as a pigment were well mixed to prepare a second resin composition.

A dry film type solder resist of the present invention and a method of manufacturing a printed wiring board using the same will be described with reference to the drawings. 1 to 4 are schematic cross-sectional views for explaining a manufacturing process and a structure of a dry film type solder resist of an embodiment of the present invention and a multilayer printed wiring board using the same. FIG. 5 is a schematic perspective view illustrating an embodiment of the present invention.

The above-mentioned first resin composition was coated on a 16 μm thick polyester film 3 by a bar coater and dried in an atmosphere of 80 ° C. for 5 minutes to obtain a 50 μm thick first resin layer 1.
Was formed. Subsequently, the above-mentioned second layer is formed on the first resin layer.
The resin composition of 1 was applied by a bar coater and dried in an atmosphere of 80 ° C. for 5 minutes to form a second resin layer 2 having a thickness of 40 μm to prepare a roll-shaped dry film.

A glass epoxy double-sided printed wiring board panel 5 having a plate thickness of 1.6 mm FR-4 having a copper foil circuit 4 having a thickness of 50 μm on its surface was coated with the above dry film at a roll temperature of 80 ° C. and a roll pressure of 3 kg / cm ^2. , Feed rate 0.5m
After laminating with a metal roll at 1 / min (FIG. 1) and trimming the unnecessary dry film, the polyester film was peeled off (FIG. 2).

When the surface of the printed wiring board panel is irradiated with ultraviolet rays of 200 mJ / cm ² through a pattern film and developed with a 1% sodium carbonate solution, the conductor circuit gap on the surface of the printed wiring board is soldered as shown in FIG. A printed wiring board completely embedded with resist was obtained. Since the pattern film can be brought into direct contact with the first resin layer at the time of exposure, a high pattern resolution of 30 to 40 μm can be obtained, but since the resin layer is tack-free, the pattern film can be easily peeled off after exposure. .

After curing the printed wiring board provided with the solder resist at 150 ° C. for 30 minutes, the lead wire 7 of the discrete component 8, the terminal 12 of the leadless component 13, and the terminal 10 of the flat package component 9 are soldered 11. A printed circuit board on which components were mounted was obtained. Since the solder resist was completely buried in the space between the conductors of the printed wiring board, the conductor circuit under the solder resist was completely protected during soldering, so there was no occurrence of solder shorts as in the past.

As shown in FIG. 5, in the printed wiring board with solder resist, the solder resist surface has smoothness regardless of the presence or absence of the conductor circuit 15 in the lower layer, so that the thickness of the solder resist insulating layer on the conductor circuit is uniform. Therefore, when the terminal 10 of the flat package component 9 is mounted on the terminal notch portion 14 of the solder resist, the positional deviation can be prevented, and thus the alignment becomes easy, and the mounting failure during mounting, the soldering failure, etc. are prevented. We were able to.

As a result of evaluating the characteristics of the printed wiring board prepared as described above, the surface insulation resistance of the solder resist is 0.15 mm between conductors, the initial value is 10 ¹² to 10 ¹³ Ω, and after the addition of moisture resistance (C- 1000/85/85, DC50V applied). Solder heat resistance is 28 in 25mm square pattern
No abnormality was found in the float test at 0 ° C. for 3 minutes. The pencil hardness tests all showed 5H or more. As chemical resistance, after immersion in 10% sodium hydroxide solution, 10% hydrochloric acid, 10% sulfuric acid, trichlorethylene, methylene chloride and isopropyl alcohol at 25 ° C for 10 minutes each, there is no abnormality in appearance and peeling strength does not deteriorate significantly. I couldn't see it. The flame retardancy was 94V-0 in the test based on UL94.

[0049]

The dry film type solder resist of the present invention has a surface smoothness which cannot be obtained by the conventional solder resist, and when the dry film solder resist of the present invention is used, the soldering reliability is high. Printed wiring boards and printed circuit boards can be manufactured with excellent mass productivity, and their industrial value is extremely high.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a process of laminating a printed circuit board in a manufacturing process using the dry film type solder resist of the present invention.

FIG. 2 is a schematic cross-sectional view showing a configuration of a printed wiring board after being laminated in the manufacturing process.

FIG. 3 is a schematic cross-sectional view showing the printed wiring board panel after exposure and development in the same manufacturing process.

FIG. 4 is a schematic cross-sectional view of the printed circuit board after mounting various electronic components in the manufacturing process.

FIG. 5 is a schematic perspective view showing an example of effectiveness when the dry film type solder resist of the present invention is used.

[Explanation of symbols]

 1 1st resin layer 2 2nd resin layer 3 Release film 4 Copper foil circuit 5 Printed wiring board panel 6 Insulating board 7 Lead wire 8 Discrete parts 9 Flat package parts 10 Terminals 11 Solder 12 Terminals 13 Leadless parts 14 Notch for terminal 15 Conductor circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenya Matsumoto Kenya Matsumoto, Aichi Prefecture 1-chome, Funami-cho, Minato-ku, Tochi Gosei Chemical Industry Co., Ltd. Nagoya Research Institute (72) Inventor Tomio Kanbayashi Nagoya, Aichi Prefecture 1 Toago Synthetic Chemical Industry Co., Ltd. Nagoya Research Institute, Minami-ku Funami-cho 1 (72) Inventor Hideki Hiraoka 1 Touna Synthetic Chemical Industry Co., Ltd. Nagoya Research Laboratories 1 Funami-cho, Minato-ku Nagoya City, Aichi Prefecture (72) Inventor Hattori Takehisa 1 Touna Synthetic Chemical Industry Co., Ltd. Nagoya Research Institute, No. 1 Funami-cho, Minato-ku, Nagoya, Aichi

Claims (2)

[Claims] 1. A layer of a first resin composition which is soluble in an alkali, has a low fluidity when heated, and has an active energy ray curability is provided on a protective film from which the layer can be peeled, and further on the layer. A dry film type solder resist, which is provided with a layer of a second resin composition which is soluble in an alkali and has a large fluidity by heating and has an active energy ray curability. 2. A first polymer composition and a second resin composition, wherein the acrylic acid is a linear polymer composed of acrylic acid and / or methacrylic acid, acrylic acid ester and / or methacrylic acid ester, and styrene. Based on a base resin obtained by adding an ethylenically unsaturated compound having a glycidyl group to a part of the carboxyl group derived from methacrylic acid and / or a crosslinking agent, an active energy ray curing reaction initiator and an active energy ray curing agent. A resin composition containing a sensitizer and having a base resin having a first molecular weight of 20,000 to 20
10,000, the second resin composition is 1,000 to 50,
The dry film type solder resist according to claim 1, wherein