WO2011018968A1 - Printed wiring board and method for producing the same - Google Patents

Abstract

Disclosed is a method for producing a high-density printed wiring board having a surface on which a high-precision and ultrafine copper circuit pattern is formed, which is comprised of (a) a process for forming a resist pattern (5) which is formed by selectively exposing and developing a photosensitive resist film formed on the substrate surface, to form a groove pattern for a circuit forming portion and which can be plated by electroless copper plating, (b) a process for forming a copper plating layer (7) which covers the resist pattern by plating an exposed surface of the groove pattern portion of a substrate and the entire surface of the patterned resist film by electroless copper plating and, thereafter, plating the surfaces by electrolytic copper plating until the surfaces are substantially flattened and smoothed, and (c) a process for exposing a copper circuit pattern (8) on the surface by mechanically grinding and/or chemically grinding or etching the copper plating layer to evenly reduce the copper plating layer until the surface of the resist film is exposed. It is preferable that the pattern-formed resist film is irradiated with ultraviolet rays, heat-treated and/or plasma-treated.

Description

Printed wiring board and manufacturing method thereof

The present invention relates to a printed wiring board and a manufacturing method thereof, and more particularly to a high-density printed wiring board having a fine circuit pattern and a manufacturing method thereof.

In order to mount electronic parts such as semiconductor parts used in electronic equipment, printed circuit boards, combined with the ultra-high density of semiconductor circuits, make their circuit conductor width and insulation space between circuits finer (fine pattern). ) Is being demanded.

Conventionally, as a circuit pattern forming method of a printed wiring board, a copper-clad laminate having a shape in which a copper foil or a copper alloy foil (generally referred to as a copper foil in this specification) is bonded to an insulating resin is used. After the photosensitive resist film is formed on the surface, the resist film is removed by selective exposure and development, and then the exposed portion of the copper foil is removed by etching, so-called etching method or copper film thinner than 5 μm is formed. After forming a photosensitive resist film on the surface of the insulating resin, the resist film is removed by selective exposure and development, and then the exposed thin copper film is used as a plating electrode by electro copper plating. Then, copper is buried in the resist film removal part, and then the resist film is removed, and then the entire surface is uniformly etched to completely remove the thin copper film on the insulating resin surface, and electro copper plating A so-called semi-subtractive method or semi-additive method for forming a circuit composed of more formed portions, or applying an electroless plating catalyst to the insulating resin surface, forming a photosensitive resist film, and then selectively After removing the resist film in the part where the circuit is formed by exposure and development, a so-called full additive method for forming a copper circuit in the resist film removal part only by electroless copper plating, and further, a metal plate used as a plating electrode A plating resist film is selectively formed on the surface, and then, by electroplating, a copper plating layer is formed on a portion where the resist film is not formed, and the resist film is removed or the resist film is not removed. It is known how to form a circuit with a copper circuit embedded in the resin by laminating with a semi-curing resin and then removing the metal plate. (For example, see Patent Documents 1 to 4).

However, any of the conventional methods described above forms a copper circuit pattern by selective etching or selective plating in a limited region, so that there are limitations on the circuit width accuracy, economy, mass productivity, etc. There is a need for a technique that can produce higher density copper circuit patterns more economically and in a more rational manner.

JP 2003-249755 A JP 2003-298243 A JP 2004-193458 A JP 2007-242975 A

The present invention has been made in view of the prior art as described above, and its purpose is to provide an ultrafine wire on the surface of a substrate such as various thermosetting resin composition laminates and thermosetting resin composition films. An object of the present invention is to provide a method for manufacturing a printed wiring board capable of manufacturing a copper circuit pattern with high accuracy and economically.
A further object of the present invention is to provide a high-density printed wiring board having a high-precision and extremely fine copper circuit pattern manufactured by such a method.

In order to achieve the object, according to the present invention,
(A) The photosensitive resist film formed on the surface of the substrate was selectively exposed and developed to form a groove pattern of a part for forming a circuit, and a pattern capable of forming a copper plating layer by electroless copper plating. Forming a resist film;
(B) Electroless copper plating is performed on the entire exposed surface of the substrate in the groove pattern portion and the patterned resist film surface, and then electrolytic copper plating is performed until the surface becomes almost smooth to cover the resist film. Forming a copper plating layer;
(C) including a step of uniformly reducing the copper plating layer by mechanical polishing and / or chemical polishing or etching until the surface of the resist film is exposed to expose a copper circuit pattern on the surface. A method for manufacturing a printed wiring board is provided.
In another aspect, after the step (c), further includes (d) a step of removing the resist film so that the surface layer portion is only a copper circuit pattern. In this step (d), the resist film is preferably removed with an alkaline aqueous solution or removed by desmearing.

In a preferred aspect, the substrate has a surface on which the copper foil of the copper clad laminate is removed by etching and the uneven surface of the copper foil is transferred.
In another preferred embodiment, the resist film is subjected to at least one treatment selected from the group consisting of ultraviolet irradiation, heat treatment and plasma treatment after pattern formation, and a copper plating layer is formed by electroless copper plating. The resist film can be formed.

In another preferred embodiment, in the step (a), the photosensitive resist film formed on the substrate surface is selectively exposed by UV pattern exposure or UV direct drawing, and then developed to form a circuit. A groove pattern of a portion to be formed is formed. Moreover, the board | substrate attached | subjected to the said process (a) has a through hole as needed.

Further, in the case of producing a multilayer printed wiring board, after the step (c), after forming an interlayer resin insulation layer, a photosensitive resist film is formed, and then the steps (a), (b) and ( Repeat c). Or after the said process (d), after forming an interlayer resin insulation layer, a photosensitive resist film is formed, and then the said process (a), (b) and (c) is repeated, and a multilayer printed wiring board is produced. To do. In this case, after the steps (a), (b), and (c) are repeated, the resist film removing step (d) may be performed so that the surface layer portion is only a copper circuit pattern.

Furthermore, according to this invention, it has a copper circuit pattern and the resin insulation layer embedded between these patterns in the surface layer part produced by one of the said methods, From these copper circuit patterns and the resin insulation layer, Provided is a printed wiring board characterized in that a flat surface is formed.

Unlike the conventional method of forming a copper circuit by selective etching or selective plating in a limited area, the printed wiring board manufacturing method of the present invention is selected as a photosensitive resist film formed on the substrate surface. The exposed surface of the substrate in the groove pattern portion and the patterned resist film in which the copper plating layer can be formed by electroless copper plating, in which the groove pattern of the circuit forming portion is formed by performing the general exposure and development, and An electroless copper plating layer is applied to the entire surface of the patterned resist film, and then electrolytic copper plating is performed until the surface is substantially smooth to form a copper plating layer covering the resist film. Until the surface is exposed, the copper plating layer is uniformly reduced by mechanical polishing and / or chemical polishing or etching to expose the copper circuit pattern on the surface. Because of the is, without the need for special processes and materials in all steps, it can be formed with good productivity high-precision fine circuit patterns. According to such a method, an ultrafine copper circuit having a width of up to about 5 μm can be easily formed, and a resist film forming step in which the groove pattern is formed, an electroless copper plating-electrolytic copper plating step, and Even in the case where a multilayer printed wiring board is manufactured by repeating the entire polishing or etching process, since the photosensitive resist is used for regulating the circuit pattern region, the alignment accuracy of the upper and lower copper circuit patterns is also good. The obtained printed wiring board is excellent in circuit width accuracy and reliability, and can be suitably used for manufacturing a substrate for mounting a semiconductor chip and manufacturing an ultra-high density printed wiring board.

It is a general | schematic fragmentary sectional view which shows the suitable embodiment of the process until it forms a photosensitive resist film on a substrate surface. An embodiment of the printed wiring board manufacturing method of the present invention including a groove pattern forming step, an electroless copper plating-electrolytic copper plating step, an overall polishing or etching step, and a resist film peeling step for a photosensitive resist film formed on a substrate surface It is a general | schematic fragmentary sectional view which shows an aspect. FIG. 3 is a schematic partial cross-sectional view showing an embodiment of a method for producing a printed wiring board including steps from resin insulation layer formation to copper circuit pattern formation according to the present invention on the printed wiring board shown in FIG. 2.

As described above, the method for manufacturing a printed wiring board according to the present invention is different from the conventional method of forming a copper circuit by selective etching or selective plating in a limited region, and the photosensitive circuit formed on the substrate surface. A patterned resist that can be electrolessly plated with copper, that is, a copper plating layer can be formed by electroless copper plating, by selectively exposing and developing the conductive resist film to form a groove pattern of a circuit forming portion. Electroless copper plating is performed on the entire exposed surface of the substrate in the groove pattern portion and the patterned resist film surface, and then the electrolytic copper plating is performed until the surface becomes almost smooth. After forming the covering copper plating layer, the copper plating layer is made uniform uniformly by mechanical polishing and / or chemical polishing or etching until the surface of the resist film is exposed. Small Toe is intended to expose the copper circuit pattern on the surface.

In general, the conventional method for forming a copper circuit pattern is based on the premise that plating (catalyst) does not adhere to the surface of a resist film formed from a commercially available plating resist, and plating is formed on a portion where no resist film exists. Designed to be In response to such a preconception, the present inventors have intensively studied to form a plating layer on the resin surface of the base material including the resist film. In particular, it has been found that pre-treatment such as ultraviolet irradiation stronger than that at the time of exposure, heating at a temperature higher than the glass transition temperature (Tg) of the resist film, or plasma treatment with argon, oxygen or the like is effective. . By performing such pretreatment, not only electroless copper plating is deposited on the resist film, but also elution is reduced, contamination of the plating solution is suppressed, discoloration of the plating surface, poor gloss, and pinholes. No plating deposition was possible. Furthermore, it became clear that the alkali resistance and the swelling of the resist film were suppressed, and the shape of the formed circuit was stable. This was an unexpected effect.

Hereinafter, a method for producing a printed wiring board of the present invention will be specifically described with reference to the accompanying drawings.
First, as shown in FIG. 1C, a substrate 1 having a photosensitive resist film 4 formed on the surface is prepared. Although FIG. 1C shows the substrate 1 having the photosensitive resist film 4 formed on both surfaces, the substrate 1 may be a substrate having the photosensitive resist film 4 formed on one side. The substrate 1 is not particularly limited as long as it is a known substrate used for a printed wiring board. Specifically, it is commonly used for non-woven fabrics and woven fabrics of glass fibers such as E, NE, D, S, and T glass defined in JIS, for example, epoxy resins, polyimide resins, cyanate ester resins, maleimide resins. , Double bond addition polyphenylene ether resins, one or two or more resin compositions such as bromine and phosphorus-containing compounds of these resins, and, if necessary, known catalysts, curing agents, curing accelerators, etc. Examples include a substrate that is impregnated with a blended thermosetting resin composition and cured. In addition, a resin substrate such as a polyimide substrate, a bismaleimide-triazine resin substrate, or a fluororesin substrate, a polyimide film, a PET film, a ceramic substrate, a wafer plate, or the like can be used. These substrates are swollen by a known roughening treatment, for example, an alkaline solution such as an aqueous sodium hydroxide solution, in order to improve the adhesion to the photosensitive resist film by forming a fine uneven flat surface on the surface. , Permanganate, dichromate, ozone, hydrogen peroxide / sulfuric acid, nitric acid-containing liquid treatment, and sulfuric acid aqueous solution, hydrochloric acid aqueous solution, etc. Treatment) can also be performed. A commercially available desmear liquid (roughening agent) can also be used for the roughening treatment.

However, in particular, as shown in FIG. 1 (A), the copper clad laminate 3 having the copper foil 2 bonded to both sides of the substrate 1 is used, and the copper foil 2 is completely removed by etching, as shown in FIG. 1 (B). It is preferable to use the board | substrate 1 which has the surface to which the uneven | corrugated surface of copper foil was transcribe | transferred. In this case, the roughening treatment described above is not required, and the photosensitive resist film 4 can be formed with good adhesion on the surface of the substrate 1 from which all the copper foil 2 has been removed by etching, and sufficient reliability as a wiring board can be obtained. It is done. As such a copper-clad laminate 3, any conventionally known copper-clad laminate can be used, but a copper foil or a resin composite copper foil, for example, as described in JP-A-2007-242975 A copper-clad laminate obtained by laminating and molding a B-stage resin composition layer on the resin layer surface of a resin composite copper foil in which a resin layer containing a block copolymerized polyimide resin and a polymaleimide compound is formed on one side of the copper foil is suitable. Can be used. The copper foil used for the resin composite copper foil is not particularly limited as long as it is a known copper foil used for printed wiring boards, but preferably an electrolytic copper foil, a rolled copper foil, a copper alloy thereof, or the like is used. The For example, nickel, cobalt treatment, or a known surface treatment such as a silane treatment agent may be used on these copper foils. The thickness of the copper foil is not particularly limited, but is preferably 35 μm or less. The surface roughness (Rz) of the copper foil surface forming the resin layer is preferably 4 μm or less, and more preferably 2 μm or less. Here, “Rz” is a ten-point average roughness defined in JIS B0601. In addition, a known adhesive layer may be formed on the copper foil.

A method of etching and removing all the copper foil 2 of the copper-clad laminate 3 can be performed by a known method. The etching solution is not particularly limited, but an aqueous solution of sulfuric acid monohydrogen peroxide, an aqueous solution of persulfate such as ammonium persulfate, sodium persulfate or potassium persulfate, an aqueous solution of ferric chloride or cupric chloride is suitable. Can be used.

As described above, the photosensitive resist film 4 is formed on the surface of the substrate 1 on which the fine uneven flat surface is formed. The photosensitive resin composition used for forming the photosensitive resist film 4 may be in the form of a dry film in which a dry coating film is formed on a carrier film, or may be in a liquid state diluted in a solvent. In the case of dry film, it is laminated on the substrate with a hot roll laminator or vacuum laminator in the temperature range of about 40 to 130 ° C. In the case of liquid, screen printing, spray coater, die coater, slit coater, curtain Tack-free by coating with a coater, roll coater, etc., drying for about 1 to 30 minutes in a hot-air circulating drying furnace or far-infrared drying furnace at a temperature of about 60 to 150 ° C., and volatilizing the solvent (temporary drying). A photosensitive resist film 4 can be formed. The film thickness of the photosensitive resist film 4 formed at this time is preferably in the range of about 3 to 30 μm, more preferably less than twice the minimum line width of the circuit formed by plating, more preferably less than or equal to the same. The photosensitive resist film 4 preferably has sufficient alkali resistance and adhesion for fixing the electroless copper plating catalyst in the subsequent electroless copper plating step.

The film used for preparing the dry film is preferably a thermoplastic resin film such as polyethylene terephthalate, and a thickness in the range of 10 to 50 μm can be used. In order to improve handling, a film thickness of 25 to 50 μm is preferable. In order to obtain image quality, a film thickness of 10 to 25 μm is preferable. In order to eliminate this difference, a dry film designed so that the refractive index of the photosensitive resist film is preferably 1.50 or more, more preferably 1.55 to 1.60 is used to increase the thickness of the carrier film. However, it is preferable because good resolution can be obtained.

The photosensitive resin composition used for forming the photosensitive resist film 4 is a negative photosensitive resin composition in which an exposed portion (a portion irradiated with active energy rays) is cured and an unexposed portion is removed by development. In addition, the unexposed part is insoluble in the developer because it has a crosslinked structure, but the exposed part is decomposed by an acid generated from a compound that generates an acid upon irradiation with active energy rays, and is removed by development. Any of the resin compositions can be used. As these photosensitive resin compositions, in consideration of environmental problems, an alkali development type photosensitive resin composition using an alkaline aqueous solution as a developer is desirable, and therefore it is preferable to contain a resin having a carboxyl group.

For example, as a positive photosensitive resin composition, a film-forming carboxyl group-containing resin, for example, a polymer unsaturated monomer containing a carboxyl group, as described in JP-A-6-295064 is disclosed. Homopolymers, copolymers of the carboxyl group-containing monomers and other copolymerizable monomers, polyesters having a carboxyl group in the molecular chain or at the molecular terminal, polyurethanes, polyamides, etc. A photosensitive resin composition comprising, as essential components, a group-containing resin, a compound containing two or more vinyl ether groups in one molecule, and a compound that generates an acid upon irradiation with active energy rays (photoacid generator), Resin obtained by reacting a polycarboxylic acid resin with a monovinyl ether compound and photoacid generation, as described in Kaihei 10-72923 A photosensitive resin composition containing, as essential components, a polyhemiacetal ester obtained from a polyaddition reaction of a dicarboxylic acid and a divinyl ether compound and a photoacid generator as described in Japanese Patent No. 4031593 A photosensitive resin composition contained as an ingredient, an alkali-soluble polymer having a phenolic hydroxyl group or a carboxyl group, a vinyl ether compound, and a photoacid generator as described in International Publication WO 99-15935A The photosensitive resin composition contained as can be used. However, depending on the carboxyl group-containing resin to be used, the negative photosensitive resin composition in which the exposed portion cured by irradiation with active energy rays remains is electroless copper without performing a pretreatment process as described later. It is particularly preferable because it can be plated.

Such a negative photosensitive resin composition comprises (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a photosensitive monomer, and a photosensitive resist film existing between copper circuits. When leaving as an insulating layer without peeling off, it is preferable to further add (D) a thermosetting resin or (E) a filler.

As the carboxyl group-containing resin (A), various conventionally known carboxyl group-containing resins having a carboxyl group in the molecule for the purpose of imparting alkali developability can be used. In particular, a carboxyl group-containing photosensitive resin (A-1) having an ethylenically unsaturated double bond in the molecule is more preferable in terms of photocurability and development resistance. And the unsaturated double bond is preferably derived from acrylic acid, methacrylic acid or derivatives thereof. In the case where only the carboxyl group-containing resin (A-2) having no ethylenically unsaturated double bond is used, in order to make the composition photocurable, two or more ethylenic groups in the molecule described later are used. It is necessary to use a compound (C) having an unsaturated group, that is, a photosensitive monomer.

In addition, a carboxyl group-containing resin (A) having a structure having an aromatic ring in the molecule is preferable because the refractive index is 1.50 to 1.60, and the refractive index with the carrier film described above is high. Since it becomes close, the resolution is improved. Examples of the carboxyl group-containing resin having an aromatic ring include styrene and its derivatives, an indene structure, a copolymer of an aromatic ring-containing (meth) acrylate such as benzyl (meth) acrylate and various (meth) acrylates, various acid-modified epoxies (meta ) Those obtained by adding an acid anhydride to an alkylene oxide modified product of acrylate or various phenol resins can be used.
Specific examples of the carboxyl group-containing resin (A) include the compounds listed below (any of oligomers and polymers).

(1) A carboxyl group-containing resin obtained by copolymerization of an unsaturated carboxylic acid such as (meth) acrylic acid and an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth) acrylate, and isobutylene.

(2) Diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, polycarbonate polyols, polyethers A carboxyl group-containing urethane resin by a polyaddition reaction of a diol compound such as a polyol, a polyester-based polyol, a polyolefin-based polyol, an acrylic polyol, a bisphenol A-based alkylene oxide adduct diol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

(3) Diisocyanate compounds such as aliphatic diisocyanate, branched aliphatic diisocyanate, alicyclic diisocyanate, aromatic diisocyanate, polycarbonate polyol, polyether polyol, polyester polyol, polyolefin polyol, acrylic polyol, bisphenol A type A terminal carboxyl group-containing urethane resin obtained by reacting an acid anhydride with a terminal of a urethane resin by a polyaddition reaction of a diol compound such as an alkylene oxide adduct diol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

(4) Diisocyanate and bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin ( A carboxyl group-containing photosensitive urethane resin obtained by a polyaddition reaction of (meth) acrylate or a partially acid anhydride-modified product thereof, a carboxyl group-containing dialcohol compound, and a diol compound.

(5) During the synthesis of the resin of the above (2) or (4), a compound having one hydroxyl group and one or more (meth) acryloyl groups in a molecule such as hydroxyalkyl (meth) acrylate is added, and the terminal ( (Meth) acrylic carboxyl group-containing urethane resin.

(6) During the synthesis of the resin of (2) or (4) above, one isocyanate group and one or more (meth) acryloyl groups are present in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate. The carboxyl group-containing urethane resin which added the compound which has and was terminally (meth) acrylated.

(7) (meth) acrylic acid is reacted with a bifunctional or higher polyfunctional (solid) epoxy resin as described later, and phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride are added to the hydroxyl group present in the side chain. A carboxyl group-containing photosensitive resin to which a dibasic acid anhydride such as

(8) (meth) acrylic acid is reacted with a polyfunctional epoxy resin obtained by epoxidizing the hydroxyl group of a bifunctional (solid) epoxy resin as described later with epichlorohydrin, and a dibasic acid anhydride is added to the resulting hydroxyl group. Added carboxyl group-containing photosensitive resin.

(9) A cyclic ether such as ethylene oxide or a cyclic carbonate such as propylene carbonate is added to a polyfunctional phenolic compound such as novolak, and the resulting hydroxyl group is partially esterified with (meth) acrylic acid, and the remaining hydroxyl group is polybasic acid. A carboxyl group-containing photosensitive resin obtained by reacting an anhydride.

(10) The resins (1) to (9) further have one epoxy group and one or more (meth) acryloyl groups in the molecule such as glycidyl (meth) acrylate and α-methylglycidyl (meth) acrylate. A carboxyl group-containing photosensitive resin obtained by adding a compound.

These carboxyl group-containing resins (A) can be used without being limited to those listed above, and can be used by mixing one kind or plural kinds. In this specification, (meth) acrylate is , Acrylate, methacrylate and mixtures thereof, and the same applies to other similar expressions.

Since the carboxyl group-containing resin (A) as described above has a large number of free carboxyl groups in the side chain of the backbone polymer, development with an aqueous alkali solution becomes possible.
The acid value of the carboxyl group-containing resin (A) is desirably in the range of 30 to 150 mgKOH / g, more preferably in the range of 40 to 110 mgKOH / g. When the acid value of the carboxyl group-containing resin is lower than 30 mgKOH / g, the solubility in an alkaline aqueous solution is lowered, and development of the formed coating film becomes difficult. On the other hand, if the concentration is higher than 150 mgKOH / g, dissolution of the exposed portion by the developer proceeds, so that the line fades more than necessary, or dissolution and peeling occurs with the developer without distinction between the exposed portion and the unexposed portion. It may be difficult to form a resist pattern.

The weight average molecular weight of the carboxyl group-containing resin (A) varies depending on the resin skeleton, but is generally in the range of 2,000 to 150,000, preferably 5,000 to 100,000. If the weight average molecular weight is less than 2,000, the tack-free performance may be inferior, the moisture resistance of the coated film after exposure may be poor, the film may be reduced during development, and the resolution may be greatly inferior. On the other hand, when the weight average molecular weight exceeds 150,000, developability may be remarkably deteriorated, and storage stability may be inferior.

The blending amount of such a carboxyl group-containing resin (A) is 20 to 80% by mass, preferably 30 to 60% by mass in the total composition. When the blending amount of the carboxyl group-containing resin (B) is less than the above range, the film strength is lowered, which is not preferable. On the other hand, when the amount is larger than the above range, the viscosity of the composition is increased or the coating property is lowered, which is not preferable.

As the photopolymerization initiator (B), conventionally known photoinitiators can be used, and conventionally known photoinitiators and sensitizers can also be used. Specific examples of photopolymerization initiators, photoinitiator assistants, and sensitizers include benzoin compounds, acetophenone compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, xanthone compounds, tertiary amine compounds, and the like. Can do.

Specific examples of the benzoin compound include benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether.
Specific examples of the acetophenone compound include acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, and 1,1-dichloroacetophenone.

Specific examples of the anthraquinone compound include 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, and 1-chloroanthraquinone.
Specific examples of the thioxanthone compound include, for example, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone.

Specific examples of the ketal compound include acetophenone dimethyl ketal and benzyl dimethyl ketal.
Specific examples of the benzophenone compound include, for example, benzophenone, 4-benzoyldiphenyl sulfide, 4-benzoyl-4′-methyldiphenyl sulfide, 4-benzoyl-4′-ethyldiphenyl sulfide, 4-benzoyl-4′-propyldiphenyl. Sulfide.

Specific examples of the tertiary amine compound include, for example, an ethanolamine compound, a compound having a dialkylaminobenzene structure, such as 4,4′-dimethylaminobenzophenone (Nisso Cure MABP manufactured by Nippon Soda Co., Ltd.), 4,4′-diethylamino. Dialkylamino benzophenones such as benzophenone (EAB manufactured by Hodogaya Chemical Co.), and dialkylamino groups such as 7- (diethylamino) -4-methyl-2H-1-benzopyran-2-one (7- (diethylamino) -4-methylcoumarin) Containing coumarin compound, ethyl 4-dimethylaminobenzoate (Kayacure EPA, Nippon Kayaku Co., Ltd.), ethyl 2-dimethylaminobenzoate (Quantacure DMB, International Bio-Synthetics), 4-dimethylaminobenzoic acid n-butoxy) ethyl (Quantacure BEA, manufactured by International Bio-Synthetics), p-dimethylaminobenzoic acid isoamyl ethyl ester (Kayacure DMBI manufactured by Nippon Kayaku Co., Ltd.), 2-ethylhexyl 4-dimethylaminobenzoic acid (Van Dyk) Esol 507), 4,4′-diethylaminobenzophenone (EAB manufactured by Hodogaya Chemical Co., Ltd.).

In addition to the photopolymerization initiator, α-aminoacetophenone photopolymerization initiator, acylphosphine oxide photopolymerization initiator, oxime ester photopolymerization initiator, and the like can be used. Examples of the α-aminoacetophenone photopolymerization initiator include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1, 2-benzyl-2-dimethylamino-1- (4- Morpholinophenyl) -butan-1-one, 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, N, N— Examples include dimethylaminoacetophenone. Examples of commercially available products include Irgacure 907, Irgacure 369, and Irgacure 379 manufactured by Ciba Japan. Examples of the acylphosphine oxide photopolymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl)- 2,4,4-trimethyl-pentylphosphine oxide and the like, and commercially available products include Lucilin TPO manufactured by BASF and Irgacure 819 manufactured by Ciba Japan. Examples of the oxime ester photopolymerization initiator include 2- (acetyloxyiminomethyl) thioxanthen-9-one, and commercially available products include CGI-325, IRGACURE OXE01, IRGA Examples include Cure OXE02 and N-1919 manufactured by Adeka Corporation.

Although typical photopolymerization initiators are listed above, any photopolymerization initiator may be used as long as it generates radical active species by light irradiation and assists the growth species, and is not limited to those described above. Moreover, although it does not raise | generate radical itself, the conventionally well-known sensitizer which has a sensitization effect with respect to the said photoinitiator can also be used. The photopolymerization initiator, photoinitiator assistant and sensitizer can be used alone or in combination of two or more. Moreover, the compounding quantity of a photoinitiator, a photoinitiator adjuvant, and a sensitizer is sufficient with a normal quantitative ratio, and generally 100 mass parts of carboxyl group-containing resin (A) (two or more kinds of carboxyl group-containing resins). In the case of using the total amount, the same applies hereinafter) to the range of 0.01 to 30 parts by mass, preferably 0.5 to 15 parts by mass. When the blending amount of the photopolymerization initiator (B) is less than 0.01 parts by mass, the photocurability is insufficient, and the coating film is peeled off or the coating film properties such as chemical resistance are deteriorated. On the other hand, if it exceeds 30 parts by mass, light absorption on the surface of the coating film of the photopolymerization initiator (B) becomes violent and the deep curability tends to decrease, which is not preferable.

The compound (C) having two or more ethylenically unsaturated groups in the molecule used in the photosensitive resin composition of the present invention is photocured by irradiation with active energy rays, and the carboxyl group-containing resin (A). Is insolubilized in an aqueous alkali solution or assists insolubilization. Examples of such compounds include glycol diacrylates such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyanurate, and the like. Polyhydric acrylates such as polyhydric alcohols or their ethylene oxide adducts or propylene oxide adducts; Phenoxy acrylate, bisphenol A diacrylate, and polyhydric acrylates such as ethylene oxide adducts or propylene oxide adducts of these phenols Glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycy Ethers, polyvalent acrylates of glycidyl ethers such as triglycidyl isocyanurate; and melamine acrylate, and / or the like each methacrylates corresponding to the acrylates and the like, can be used alone or in combination of two or more.

Further, an epoxy acrylate resin obtained by reacting acrylic acid with a polyfunctional epoxy resin such as a cresol novolac type epoxy resin, and further, a hydroxy acrylate such as pentaerythritol triacrylate and a diisocyanate such as isophorone diisocyanate on the hydroxyl group of the epoxy acrylate resin. Examples thereof include an epoxy urethane acrylate compound obtained by reacting a half urethane compound. Such an epoxy acrylate resin can improve photocurability without deteriorating the touch drying property.

The compounding amount of the compound (C) having two or more ethylenically unsaturated groups in the molecule is 5 to 100 parts by mass, more preferably 100 parts by mass of the carboxyl group-containing resin (A). A ratio of 1 to 70 parts by mass is appropriate. When the blending amount is less than 5 parts by mass, photocurability is lowered, and pattern formation becomes difficult by alkali development after irradiation with active energy rays, which is not preferable. On the other hand, when the amount exceeds 100 parts by mass, the solubility in an alkaline aqueous solution is lowered, and the coating film becomes brittle.

Furthermore, a thermosetting component (D) can be added to the photosensitive resin composition used in the present invention in order to impart heat resistance. As thermosetting component (D), amino resins such as melamine resin and benzoguanamine resin, bismaleimide compound, benzoxazine compound, oxazoline compound, carbodiimide resin, block isocyanate compound, cyclocarbonate compound, polyfunctional epoxy compound, polyfunctional oxetane compound Well-known and commonly used thermosetting resins such as episulfide resins and melamine derivatives can be used. Among these, a particularly preferable thermosetting component (D) is a thermosetting component having two or more cyclic ether groups and / or cyclic thioether groups (hereinafter abbreviated as cyclic (thio) ether groups) in one molecule. For example, a polyfunctional epoxy compound having two or more epoxy groups in the molecule, a polyfunctional oxetane compound having two or more oxetanyl groups in the molecule, and an episulfide resin having two or more thioether groups in the molecule It is. The amount of the thermosetting component (D) is preferably 0.6 to 2.5 equivalents, more preferably 0.8 to 2.1, based on 1 equivalent of the carboxyl group of the carboxyl group-containing resin (A). It is a range that becomes 0 equivalent.

When the photosensitive resin composition contains the thermosetting component (D) as described above, it is preferable to further contain a thermosetting catalyst. Examples of such thermosetting catalysts include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole. Imidazole derivatives such as 1- (2-cyanoethyl) -2-ethyl-4-methylimidazole; dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy-N, N -Amine compounds such as dimethylbenzylamine and 4-methyl-N, N-dimethylbenzylamine; hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; and phosphorus compounds such as triphenylphosphine. Examples of commercially available products include 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, 2P4MHZ (both trade names of imidazole compounds) manufactured by Shikoku Kasei Kogyo Co., Ltd. and U-CAT (registered by San Apro). Trademarks) 3503N, U-CAT3502T (all are trade names of blocked isocyanate compounds of dimethylamine), DBU, DBN, U-CATSA102, U-CAT5002 (all are bicyclic amidine compounds and salts thereof), and the like. In particular, it is not limited to these, as long as it is a thermosetting catalyst for epoxy resins or oxetane compounds, or a catalyst that promotes the reaction of epoxy groups and / or oxetanyl groups with carboxyl groups, either alone or in combination of two or more. Can be used. Guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino S-triazine derivatives such as -S-triazine / isocyanuric acid adducts and 2,4-diamino-6-methacryloyloxyethyl-S-triazine / isocyanuric acid adducts can also be used. A compound that also functions in combination with the thermosetting catalyst. The blending amount of these thermosetting catalysts is sufficient in the usual quantitative ratio, for example, a carboxyl group-containing resin (A) or a thermosetting component (D) having two or more cyclic (thio) ether groups in the molecule. The amount is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 15.0 parts by mass with respect to 100 parts by mass.

In the photosensitive resin composition used in the present invention, a filler (E) can be blended as necessary in order to increase the physical strength of the coating film. As such a filler, known and commonly used inorganic or organic fillers can be used. In particular, barium sulfate, spherical silica and talc are preferably used. Furthermore, in order to obtain a white appearance and flame retardancy, metal hydroxides such as titanium oxide, metal oxide, and aluminum hydroxide can be used as extender pigment fillers. The blending amount of the filler is preferably 75% by mass or less, more preferably 0.1 to 60% by mass of the total amount of the composition. If the blending amount of the filler exceeds 75% by mass of the total amount of the composition, the viscosity of the insulating composition is increased, and the coating and moldability are lowered, and the cured product becomes brittle.

The photosensitive resin composition used in the present invention is a ketone, an aromatic hydrocarbon, a glycol ether, a glycol ether acetate for adjusting the viscosity for preparing the composition or for applying to a substrate or a carrier film. In addition, various organic solvents such as esters, alcohols, aliphatic hydrocarbons and petroleum solvents can be blended. Further, if necessary, known conventional polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, pyrogallol, phenothiazine, etc., known conventional thickeners such as finely divided silica, organic bentonite, montmorillonite, pigments, dyes, silicones Known and conventional additives such as antifoaming agents and / or leveling agents such as fluorinated and fluoropolymers, silane coupling agents such as imidazole, thiazole and triazole, antioxidants and rust inhibitors Can be blended.

(1) Patterned resist film formation step As shown in FIG. 1 (C), through holes 6 were formed by drilling as necessary in the substrate 1 having the photosensitive resist film 4 formed on the surface. Thereafter, selective exposure and development are performed, and as shown in FIG. 2 (A), a patterned resist in which a groove pattern of a circuit forming portion is formed and a copper plating layer can be formed by electroless copper plating. A film (hereinafter simply referred to as a resist film or a resist pattern) 5 is formed. When the negative photosensitive resin composition is used to form the photosensitive resist film 4, the unexposed portion is removed by development, and when the positive photosensitive resin composition is used, the exposed portion is removed by development. Removed. The selective exposure can be performed by an active energy ray selectively through a photomask having a pattern formed by a contact method (or non-contact method), or directly by a laser direct exposure machine. Further, when the photosensitive resin composition used for forming the photosensitive resist film contains a thermosetting component (D), by further heating and curing, the heat resistance, chemical resistance, Various characteristics such as moisture absorption resistance, adhesion, and electrical characteristics can be improved.

As the exposure apparatus used for the active energy ray irradiation, a direct drawing apparatus (for example, a laser direct imaging apparatus that directly draws an image with a laser using CAD data from a computer), an exposure apparatus equipped with a metal halide lamp, and an (ultra) high pressure mercury lamp. , An exposure machine equipped with a mercury short arc lamp, or a direct drawing apparatus using an ultraviolet lamp such as a (super) high pressure mercury lamp. As the active energy ray, either a gas laser or a solid laser may be used as long as laser light having a maximum wavelength in the range of 350 to 410 nm is used. The exposure amount varies depending on the film thickness and the like, but can be generally in the range of 5 to 200 mJ / cm ² , preferably 5 to 100 mJ / cm ² , more preferably 5 to 50 mJ / cm ² . As the direct drawing apparatus, for example, those manufactured by Nippon Orbotech, Pentax, etc. can be used, and any apparatus may be used as long as it oscillates laser light having a maximum wavelength of 350 to 410 nm. .

The developing method may be a dipping method, a shower method, a spray method, a brush method, or the like. Although development with a solvent is possible, development is preferably performed using an alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines and the like.

(2) Electroless Copper Plating—Electrolytic Copper Plating Step As shown in FIG. 2B, the electroless copper plating step is performed on the entire exposed surface of the substrate 1 and the surface of the resist pattern 5 in the groove pattern portion, Copper plating is performed, and then electrolytic copper plating is performed until the surface becomes substantially smooth, thereby forming a copper plating layer 7 covering the resist pattern 5.
At this time, prior to the electroless copper plating, as a pretreatment for forming the electroless copper plating on the surface of the resist pattern 5, the resist pattern 5 after development is further irradiated with ultraviolet rays stronger than at the time of exposure, Alternatively, it is preferable to perform heating at a temperature equal to or higher than the glass transition temperature (Tg) of the resist film or plasma treatment with argon, oxygen, or the like. By performing such pretreatment, not only electroless copper plating is deposited on the resist pattern 5, but also elution is reduced, contamination of the plating solution is suppressed, discoloration of the plating surface, poor gloss, pinholes, etc. It is also possible to deposit plating without any metal. Furthermore, alkali resistance and resist film swelling are suppressed, and the shape of the formed circuit is stabilized.

In electroless copper plating, generally, a palladium catalyst is applied to the entire exposed surface of the substrate and the patterned resist film surface, and then immersed in an electroless copper plating solution to form a copper layer. In general, the thickness of the electroless copper plating layer is suitably in the range of about 0.5 to 2 μm. If necessary, heat treatment is performed at 100 ° C. to 200 ° C. after forming the electroless copper plating layer. The heating time is not particularly limited, but is preferably selected from 30 minutes to 5 hours. In order not to oxidize the copper foil, heating in a vacuum or in an inert gas is preferable. Next, it is immersed in an electrolytic copper plating solution to cover the resist pattern 5 as shown in FIG. 2B, and an electrolytic copper plating layer is formed until the surface of the copper plating layer 7 becomes substantially smooth. The thickness of the electrolytic copper plating layer can be arbitrarily selected.

(3) Etching Step After forming the copper plating layer 7 as shown in FIG. 2 (B), the copper plating layer 7 until the surface of the resist pattern 5 is exposed as shown in FIG. 2 (C). Are uniformly reduced by mechanical polishing and / or chemical polishing or etching to expose the copper circuit pattern 8 on the surface. As a result, the upper and lower copper circuit patterns 8 are connected by the plated through holes 9. A conventionally known method can be used for mechanical polishing and / or chemical polishing, and the etching solution is not particularly limited, but is an aqueous solution of sulfuric acid monohydrogen peroxide, ammonium persulfate, sodium persulfate, persulfate. An aqueous solution of persulfate such as potassium or an aqueous solution of ferric chloride or cupric chloride can be preferably used.

(4) Resist film stripping step The resist pattern 5 that is embedded between the copper circuit patterns 8 can be left as it is as an insulating layer without being stripped, but if necessary, only the resist pattern 5 can be used as an alkaline aqueous solution. , Swelling and peeling with a solvent and / or so-called desmear treatment with an alkali permanganate or the like, and removing, so that only the copper circuit pattern 8 was formed on the substrate 1 as shown in FIG. It can be a wiring board.

(5) Interlayer resin insulation layer forming step When a multilayer printed wiring board is manufactured, a substrate having a resist pattern 5 and a copper circuit pattern 8 as shown in FIG. 2 (C) or FIG. 2 (D). As shown in FIG. 4, on the surface of the substrate having only the copper circuit pattern 8, for example, epoxy resin, polyimide resin, cyanate ester resin, maleimide resin, double bond addition polyphenylene ether resin, bromine or phosphorus-containing compounds of these resins 1 type or 2 or more types such as resin composition and the like, and if necessary, a thermosetting resin composition containing a known catalyst, curing agent, curing accelerator, etc. is applied and cured by heating, or glass Non-woven fabrics, woven fabrics, etc. are impregnated with thermosetting resin composition, and semi-cured semi-solid brigregs are laminated, or film-like resin is laminated by thermocompression bonding. Then, as shown in FIG. 3A, the interlayer resin insulating layer 10 is formed, and the roughening treatment as described above is performed on the surface as necessary. Also in this case, preferably, a copper foil or a resin composite copper foil, for example, a resin layer containing a block copolymerized polyimide resin and a polymaleimide compound on one side of a copper foil as described in JP-A-2007-242975 The resin layer surface of the resin composite copper foil formed with the B-stage resin composition layer is laminated, the laminated copper-clad laminate is laminated, and then all the copper foil is removed by etching, whereby the fine uneven surface of the copper foil An interlayer resin insulation layer 10 having a surface to which is transferred is formed. In this case, the roughening treatment described above becomes unnecessary, and a photosensitive resist film can be formed with good adhesion on the surface of the interlayer resin insulating layer 10 in a later process, and sufficient reliability as a wiring board can be obtained. As such a copper clad laminate, all conventionally known copper clad laminates can be used. Alternatively, the photosensitive resin composition containing the thermosetting component (D) and the filler (E) described above is applied to the surface of the substrate, or the dry film is laminated, so that the active energy ray is entirely applied. The interlayer resin insulation layer 10 can also be formed by irradiating and photocuring, and further heating and thermosetting.

In the resin composition used for the B-stage resin composition layer, various additives can be blended as desired as long as the original characteristics of the composition are not impaired. These additives include polymerizable double bond-containing monomers such as unsaturated polyesters and prepolymers thereof; polybutadiene, maleated butadiene, butadiene-acrylonitrile copolymer, polychloroprene, butadiene-styrene copolymer, poly Low molecular weight liquid to high molecular weight elastic rubbers such as isoprene, butyl rubber, fluoro rubber, natural rubber; polyethylene, polypropylene, polybutene, poly-4-methylpentene, polystyrene, AS resin, ABS resin, MBS resin, styrene-isoprene Rubber, acrylic rubber, core-shell rubber, polyethylene-propylene copolymer, 4-fluorinated ethylene-6-fluorinated ethylene copolymers; polycarbonate, polyphenylene ether, polysulfone, polyester, polyphenylene sulfide High molecular weight prepolymers or oligomers such as id, polyurethane, etc. are exemplified, are appropriately used. Other known organic or inorganic fillers, dyes, pigments, thickeners, lubricants, antifoaming agents, dispersants, leveling agents, photosensitizers, flame retardants, brighteners, polymerization inhibitors, thixotropic agents Various additives such as are used in appropriate combination as desired. In particular, when drilling with a carbon dioxide laser, an inorganic filler is suitably added to improve the hole shape. For example, generally known materials such as silica, spherical silica, alumina, talc, calcined talc, wollastonite, synthetic mica, titanium oxide, and aluminum hydroxide are used. The shape of these fillers may be any shape such as a needle shape or a spherical shape.

(6) Resist pattern forming step A photosensitive resist film is formed as described above on the substrate 1 on which the interlayer resin insulating layer 10 is formed as shown in FIG. 3A, and via holes 11 are formed as necessary. Then, selective exposure and development are performed on the photosensitive resist film in the same manner as in the step (1), so that a groove pattern of a part for forming a circuit is formed as shown in FIG. Further, an outer layer resist pattern 12 that can form a copper plating layer is formed by electroless copper plating. In the case where the photosensitive resin composition used for forming the photosensitive resist film contains a thermosetting component (D), for example, it is heated to a temperature of about 140 to 180 ° C. to be thermally cured, whereby the carboxyl The carboxyl group of the group-containing resin (A) reacts with the thermosetting component (D) having two or more cyclic (thio) ether groups in the molecule, resulting in heat resistance, chemical resistance, moisture absorption resistance, and adhesion. It is possible to form a cured film excellent in various characteristics such as electrical characteristics. Even when the thermosetting component (D) is not contained, the heat treatment causes the ethylenically unsaturated bond of the photocurable component remaining in an unreacted state at the time of exposure to undergo thermal radical polymerization, and the film characteristics are improved. In order to improve, heat treatment (thermosetting) may be performed depending on the purpose and application.

(7) Electroless Copper Plating—Electrolytic Copper Plating Step Thereafter, the exposed surface of the interlayer resin insulation layer 10 and the entire surface of the resist pattern 12 are shown in FIG. As described above, electroless copper plating is performed, and then electrolytic copper plating is performed until the surface becomes substantially smooth, so that an outer copper plating layer 13 covering the resist pattern 12 is formed. Also in this case, as in the step (2), prior to the electroless copper plating, as a pretreatment for forming the electroless copper plating on the surface of the resist pattern 12, the resist pattern 12 after development is applied. Further, it is preferable to perform ultraviolet irradiation stronger than that at the time of exposure, heating at a temperature equal to or higher than the glass transition temperature (Tg) of the resist film, or plasma treatment with argon, oxygen, or the like.

(8) Etching Step After forming the outer copper plating layer 13 as shown in FIG. 3C, the copper plating layer is used until the surface of the resist pattern 12 is exposed in the same manner as in the step (3). 13 is uniformly reduced by mechanical polishing and / or chemical polishing or etching, and as shown in FIG. 3D, the copper circuit pattern 14 of the outer layer is exposed on the surface. The resist pattern 12 embedded between the copper circuit patterns 14 can be left as it is as an insulating layer without being peeled off, and if necessary, only the resist pattern 12 is swollen and peeled off with an alkaline aqueous solution, a solvent, And / or a so-called desmearing process can be performed to remove the surface layer portion, so that a wiring board having only the outer layer copper circuit pattern 14 formed on the surface layer portion can be obtained.

Furthermore, a multilayer printed wiring board can be produced with high productivity by repeating the steps (5) to (8) described above.
The circuit pattern formed by the method of the present invention as described above has excellent insulation reliability because no conductor can exist between the circuit patterns even when the line and space is thinner than 5 μm. Circuit.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. However, the present invention is not limited to the following examples. In the following description, “parts” and “%” are based on mass unless otherwise specified.

Preparation of photosensitive resist composition:
Various components shown in Table 1 below were blended in proportions (parts by mass) shown in Table 1, premixed with a stirrer, and then kneaded with a three-roll mill to prepare a photosensitive resist composition.

Production of dry film:
Each of the obtained photosensitive resist compositions was further diluted with propylene glycol methyl ether acetate to obtain a 10 dPa · s resist solution. It was applied to a polyethylene terephthalate film having a thickness of 16 μm with a film coater, and the temperature was gradually increased from 50 ° C. to 80 ° C. to dry, thereby obtaining a dry film having a resist thickness of 10 μm. Let the obtained dry film be the dry film A and the dry film B, respectively.

Example 1
BT resin copper-clad laminate (product name: CCL-HL830, manufactured by Mitsubishi Gas Chemical Co., Inc.) having an insulation layer thickness of 0.2 mm and double-sided copper foil (copper foil profile 3.3 μm) as a copper-clad laminate A through hole with a hole diameter of 75 μm is formed with a metal drill, and after swelling with desmear treatment (potassium permanganate desmear solution (Okuno Pharmaceutical Co., Ltd.)), desmear (dissolution), neutralized, washed with water, the surface copper foil layer Then, the dry film A was laminated with a vacuum laminator manufactured by Nichigo Morton under the conditions of 70 ° C., 0.5 MPa, 30 seconds, and then 355 nm using a laser direct exposure apparatus (Orbotech Co., Paragon). minimum line and space ultraviolet under the conditions of 100 mJ / cm ² is drawing the pattern is 10 [mu] m. Thereafter, the 30 ° C. With wt% sodium carbonate aqueous solution was developed at a spray pressure of 2 atm, washed with water twice, to obtain a substrate with a photosensitive resist pattern is formed.
This was UV cured under a condition of 300 mJ / cm ² with a UV conveyor device equipped with a high-pressure mercury lamp, and then subjected to plasma treatment with oxygen plasma under conditions of 500 W, 250 mTorr, and 60 seconds.
Subsequently, electroless copper plating is performed using an electroless copper plating solution (Akusatsu Pharmaceutical Co., Ltd., ATS Adcopper CT) to form a 1 μm thick copper layer on the entire surface. After heating for a period of time, electrolytic plating was performed for 70 minutes at 1.5 amperes / dm ² using a copper sulfate plating solution to form a copper layer having a thickness of about 10 μm. The copper foil was etched flatly on the substrate on which the copper layer was formed using an etching solution (SE-07, manufactured by Mitsubishi Gas Chemical Co., Ltd.) until the surface of the dry film was seen. The substrate on which the circuit is formed is stripped with an alkali stripping solution (Mitsubishi Gas Chemical Co., Ltd., R-200) at 50 ° C. for 3 minutes, and the photosensitive resist is completely removed by a desmear process. A circuit board having a line and space of 10 μm was obtained.

Example 2
After the circuit board obtained in Example 1 was subjected to CZ treatment by MEC, a B-stage resin composition sheet with copper foil (copper foil profile 3.3 μm) (manufactured by Mitsubishi Gas Chemical Co., Ltd., CRS-401) ) On both sides, heating conditions: 110 ° C. × 30 minutes + 180 ° C. × 90 minutes, pressurization conditions: 5 kgf / cm ² × 15 minutes + 20 kgf / cm ² , under the conditions up to the end, with a vacuum of 30 mmHg or less for 2 hours Lamination was performed under conditions. The copper foil on the surface of the obtained four-layer plate was etched, and a blind via hole having a hole diameter of 60 μm was formed by irradiating one shot with a carbon dioxide laser (output: 13 mJ). Next, the dry film A was laminated under the above conditions, and thereafter, circuit formation was performed in the same manner as in Example 1 to obtain a four-layer circuit board having a minimum line and space of 10 μm.

Example 3
In Example 1, instead of the dry film A, the dry film B was similarly laminated on a copper-clad laminate obtained by etching the entire copper foil layer on the surface, and thereafter, similarly, a laser direct exposure apparatus (manufactured by Orbotech, Paragon) was used. A pattern having a minimum line and space of 20 μm was drawn using ultraviolet rays of 355 nm under the condition of 200 mJ / cm ² . Thereafter, development was performed using a 1 wt% sodium carbonate aqueous solution at 30 ° C. with a spray pressure of 2 atm, and washing with water was repeated twice to obtain a substrate on which a photosensitive resist pattern was formed.
This was cured in a hot air drying furnace at 150 ° C. for 1 hour, and then plasma treatment was performed with oxygen plasma under conditions of 500 w, 250 mTorr, and 60 seconds.
Next, electroless copper plating is performed using an electroless copper plating solution (Akusatsu Pharmaceutical Co., Ltd., ATS Adcopper CT) to form a 1 μm thick copper layer, which is heated in a heating furnace at 130 ° C. for 2 hours. After that, electrolytic copper plating was performed for 70 minutes at 1.5 ampere / dm ² using a copper sulfate plating solution to form a copper layer having a thickness of about 10 μm. Using this etching solution (SE-07, manufactured by Mitsubishi Gas Chemical Co., Inc.), the copper foil is etched flatly until the surface of the dry film is seen, and the minimum line and space is formed on the substrate on which the copper layer is formed. Obtained a circuit board of 20 μm.

Example 4
The circuit board obtained in Example 3 was subjected to CZ treatment by MEC and subjected to adhesion treatment, and then dry film B was laminated thereon in the same manner as in Example 1 to expose and develop the solder resist pattern. Thereafter, the substrate was thermally cured at 150 ° C. for 1 hour in a hot air drying furnace to obtain a circuit board on which a solder resist was formed.

Example 5
After the four-layer circuit board obtained in Example 2 was subjected to CZ treatment by MEC, a dry film solder resist (manufactured by Taiyo Ink Manufacturing Co., Ltd., AUS410, 20 μm film thickness) was laminated in the same manner as in Example 1. The solder resist pattern was exposed and developed with a high-pressure mercury lamp at 600 mJ / cm ² and then thermally cured at 150 ° C. for 1 hour in a hot air drying oven to obtain a circuit board on which the solder resist was formed.

Comparative Example 1
BT resin copper-clad laminate (product name: CCL-HL830, manufactured by Mitsubishi Gas Chemical Co., Inc.) with an insulating layer thickness of 0.2 mm and double-sided copper foil (copper foil profile 3.3 μm) as a copper-clad laminate A through-hole with a hole diameter of 75 μm was formed with a metal drill, and then the copper foil layer on the surface was etched flat with an etching solution (SE-07, manufactured by Mitsubishi Gas Chemical Co., Ltd.) until it became 2.0 μm, and desmear treatment (excessive treatment) After swelling, desmear (dissolution), neutralization, and washing with a potassium manganate desmear solution (Okuno Pharmaceutical Co., Ltd.), electroless copper plating is performed to form a copper layer of about 1 μm, and then at 130 ° C. Heat treatment was performed for 2 hours, and a dry film for semi-additive (manufactured by Hitachi Chemical Co., Ltd., RY-3515) was vacuum-laminated by a Nichigo Morton vacuum laminator at 70 ° C., 0.5 MPa for 30 seconds. After that, a pattern having a minimum line and space of 10 μm was drawn under the condition of 100 mJ / cm ² using ultraviolet exposure equipment (HAP-5020, manufactured by Hakuto Co., Ltd.). Development was performed using a 1 wt% sodium carbonate aqueous solution at 30 ° C. under a spray pressure of 2 atm, and washing with water was repeated twice to obtain a substrate on which a photosensitive resist pattern was formed. Electrolytic copper plating was performed at 5 amps / dm ² for 70 minutes to form a copper pattern having a thickness of about 10 μm on the portion where the resist was not formed.The substrate was then subjected to alkaline stripping solution (Mitsubishi Gas Chemical Co., Ltd., R-200) at 50 ° C. for 3 minutes, the semi-additive dry film is peeled off, and then the semi-additive dry film of the substrate on which the copper pattern is formed is formed. Until there is no beam has been formed portion, an etching solution (Mitsubishi Gas Chemical Co., Ltd., SE-07) a copper circuit is etched using the minimum line-and-space was obtained circuit board 10 [mu] m.

Comparative Example 2
After the circuit board prepared in Comparative Example 1 was subjected to CZ treatment by MEC, a thermosetting dry film (Ajinomoto Fine Techno Co., Ltd., ABF-GX13) was laminated on both sides, and a vacuum laminator manufactured by Nichigo Morton was used. Lamination was carried out under the conditions of 0 ° C., 0.5 Mpa, and 30 seconds, and then heat-cured at 170 ° C. for 60 minutes in a hot air drying furnace to laminate. The obtained substrate was irradiated with one shot with a carbon dioxide laser (output: 13 mJ) to form blind via holes having a hole diameter of 60 μm. Next, it is swollen, desmeared (dissolved), neutralized by desmear treatment (potassium permanganate-based desmear solution (manufactured by Nihon McDermid Co., Ltd.)), and removal of smears in blind via holes and uneven treatment of the cured surface of the thermosetting dry film The unevenness of the resin surface at this time was Rz 5.3 μm, and electroless copper plating was performed on this substrate using an electroless copper plating solution (ATS ADCAPPER CT, manufactured by Okuno Pharmaceutical Co., Ltd.). After forming a copper layer having a thickness of 1 μm and heating in a heating furnace at 130 ° C. for 2 hours, the semi-additive dry film was subjected to conditions of 70 ° C., 0.5 Mpa, 30 seconds with a vacuum laminator manufactured by Nichigo Morton. Thereafter, the minimum line and space is 10 μm under the condition of 100 mJ / cm ² using ultraviolet exposure apparatus (manufactured by ORC). After that, the pattern was drawn, developed using a 1 wt% sodium carbonate aqueous solution at 30 ° C. with a spray pressure of 2 atm, and washed twice with water to obtain a substrate on which a photosensitive resist pattern was formed. On the other hand, electrolytic copper plating was performed at 1.5 ampere / dm ² for 70 minutes using a copper sulfate plating solution to form a copper pattern having a thickness of about 10 μm on the portion where no resist was formed. After the semi-additive dry film was peeled off at 50 ° C. for 3 minutes using a stripping solution (Mitsubishi Gas Chemical Co., Ltd., R-200), the semi-additive dry film on the substrate on which the copper pattern was formed was The copper circuit is etched using an etching solution (SE-07, manufactured by Mitsubishi Gas Chemical Co., Ltd.) until the copper portion that has been formed disappears, and the minimum line and space A multilayer circuit board having a thickness of 10 μm was obtained.
Further, in the same manner as in Example 5, a solder resist pattern of a dry film solder resist (manufactured by Taiyo Ink Manufacturing Co., Ltd., AUS410) was formed on this substrate to obtain a substrate on which the solder resist was formed.

A characteristic test as described later was performed on the circuit boards prepared in each of the examples and comparative examples. The results are shown in Table 2.

(1) Peel strength:
In accordance with JIS C6481, the average value of the peel strength measured three times was shown.

(2) Solder heat resistance:
After being treated at 121 ° C. and 203 kPa for 4 hours and immersed in a solder solution at 260 ° C. for 30 seconds, the presence or absence of abnormalities such as circuit peeling and resin peeling was observed and evaluated according to the following criteria.
○: No abnormality ×: Partial swelling

(3) Fine wire formability:
It was confirmed with a microscope whether the formed fine line of L / S (line / space) = 10/10 μm or L / S = 20/20 μm was formed, and evaluated according to the following criteria.
○: Formed without problems.
(Triangle | delta): Peeling is seen in a part.
X: Peeling is observed.

(4) Electroless gold plating suitability:
Each wiring board was subjected to electroless nickel plating, further electroless gold plating, and the presence or absence of abnormal deposition of plating due to etching residues during circuit formation was confirmed and evaluated according to the following criteria.
○: No abnormal precipitation.
X: Plating is deposited even on the resin without wiring.

As shown in Table 2, in Examples 1 to 5, the circuit board was formed by etching the entire copper foil and having the surface roughness of the copper foil profile, so the peel strength was high. Results were obtained. In addition, after forming an electrolytic copper plating seed layer (conductive layer) on the entire surface of the substrate and the photosensitive resist film by electroless copper plating, and then forming an electrolytic copper plating layer on the entire surface, the photosensitive resist film surface is Wiring boards formed by etching flat until exposed are high-definition and there is no history of conductive layer formation between completed circuits, so there is no possibility of abnormal deposition in nickel and gold plating due to etching failure. It was.
Further, the wiring boards obtained in Example 3 and Example 4 were high-precision forming methods in which the circuit and the insulating layer were flat and the solder resist layer could be formed with a uniform film thickness.
On the other hand, in the case of the comparative example 1, since all the copper foil of the wiring board was etched and the circuit was formed with the surface roughness of the copper foil profile as in the example, the peel strength was relatively high. there were. However, since the profile on the base resin was large, peeling of fine lines, which seems to be caused by overetching when peeling the copper foil layer, was observed. On the other hand, in Comparative Example 2, since the unevenness was formed on the resin by the desmear process without using the copper foil profile, the peel strength of the completed circuit was lower than that of the example. Furthermore, when electroless nickel or electroless gold plating, which is a post-treatment of the wiring board, was formed, the plating was abnormally deposited on the resin other than the wiring. This is presumably because the electroless copper plating was formed between the thin wires (under the photosensitive resist film), so that palladium which was the catalyst for the electroless copper plating remained unetched even after etching.

The method for manufacturing a printed wiring board of the present invention is suitable for manufacturing a high-density printed wiring board or a multilayer printed wiring board in which a highly accurate and extremely fine copper circuit pattern is formed on the surface of a substrate.

1: Substrate 2: Copper foil 3: Copper-clad laminate 4: Photosensitive resist film 5: Resist pattern 6: Through hole 7: Copper plating layer 8: Copper circuit pattern 9: Plating through hole 10: Interlayer resin insulation layer 11: Via hole 12: Resist pattern of outer layer 13: Copper plating layer of outer layer 14: Copper circuit pattern of outer layer

Claims (12)

1. (A) The photosensitive resist film formed on the surface of the substrate was selectively exposed and developed to form a groove pattern of a part for forming a circuit, and a pattern capable of forming a copper plating layer by electroless copper plating. Forming a resist film;
   (B) Electroless copper plating is performed on the entire exposed surface of the substrate in the groove pattern portion and the patterned resist film surface, and then electrolytic copper plating is performed until the surface becomes almost smooth to cover the resist film. Forming a copper plating layer;
   (C) including a step of uniformly reducing the copper plating layer by mechanical polishing and / or chemical polishing or etching until the surface of the resist film is exposed to expose a copper circuit pattern on the surface. Manufacturing method of printed wiring board.
2. The method according to claim 1, further comprising the step of (d) removing the resist film so that the surface layer portion is only a copper circuit pattern after the step (c).
3. The method according to claim 1, wherein the substrate has a surface on which the copper foil of the copper-clad laminate is removed by etching and the uneven surface of the copper foil is transferred.
4. The resist film is a resist film capable of forming a copper plating layer by electroless copper plating by performing at least one treatment selected from the group consisting of ultraviolet irradiation, heat treatment and plasma treatment after pattern formation. The method of claim 1, wherein:
5. In the step (a), the photosensitive resist film formed on the surface of the substrate is selectively exposed by UV pattern exposure or direct UV exposure, and then developed to form a groove pattern of a circuit forming portion. The method according to claim 1.
6. 3. The method according to claim 2, wherein in the step (d), the resist film is removed with an alkaline aqueous solution or removed by desmear treatment.
7. The method according to claim 1, wherein the substrate subjected to the step (a) has a through hole.
8. After the step (c), after forming an interlayer resin insulation layer, a photosensitive resist film is formed, and then the steps (a), (b) and (c) are repeated to produce a multilayer printed wiring board. The method of claim 1, wherein:
9. After the step (d), after forming an interlayer resin insulation layer, a photosensitive resist film is formed, and then the steps (a), (b) and (c) are repeated to produce a multilayer printed wiring board. The method according to claim 2.
10. The resist film removing step (d) is performed after the steps (a), (b) and (c) are repeated, so that the surface layer portion is only a copper circuit pattern. 9. The method according to 8.
11. The resist film removing step (d) is performed after the steps (a), (b) and (c) are repeated, so that the surface layer portion is only a copper circuit pattern. 9. The method according to 9.
12. A copper circuit pattern and a resin insulating layer embedded between the patterns, which are produced by the method according to claim 1 or 3 to 9, and are embedded between the patterns. A printed wiring board, wherein a flat surface is formed from a resin insulating layer.

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