CN116438063A

CN116438063A - Laminate for semi-additive method and printed wiring board using same

Info

Publication number: CN116438063A
Application number: CN202180074824.1A
Authority: CN
Inventors: 深泽宪正; 村川昭; 白发润
Original assignee: DIC Corp
Current assignee: DIC Corp
Priority date: 2020-11-05
Filing date: 2021-10-21
Publication date: 2023-07-14
Also published as: WO2022097482A1; KR20230104147A; JP7201130B2; JPWO2022097482A1; TW202233415A

Abstract

The present invention provides a planar semi-additive laminate for double-sided connection which can form a wiring having high adhesion between a substrate and a conductor circuit, less undercut, excellent design reproducibility, and a good rectangular cross-sectional shape as a circuit wiring without using chromic acid, surface roughening of permanganic acid, formation of a surface modified layer with alkali, and the like, and without using a vacuum apparatus, and a printed wiring board using the same. It has been found that by using a laminate in which a conductive silver particle layer (M1) and a releasable cover layer (RC) are laminated in this order on both surfaces of an insulating substrate (a), a printed wiring board having high adhesion between the substrate and a conductor circuit, less undercut, excellent design reproducibility, and a rectangular cross-sectional shape as a circuit wiring, which is connected on both sides, can be formed without complicated surface roughening and without forming a surface-modified layer, and the present invention has been completed.

Description

Laminate for semi-additive method and printed wiring board using same

Technical Field

The present invention relates to a planar stack for a semi-additive method for electrically connecting both surfaces of a substrate and a printed wiring board using the same.

Background

The printed wiring board is formed by forming a metal layer of a circuit pattern on the surface of an insulating base material. In recent years, along with the demand for miniaturization and weight reduction of electronic equipment products, there is a demand for a printed wiring board (film) having a reduced thickness and a circuit wiring having a higher definition. Conventionally, as a method for manufacturing a circuit wiring, a subtractive method of forming a circuit pattern-shaped etching resist on a surface of a copper layer formed on an insulating substrate, and etching a copper layer in a portion where a circuit is not necessary to form a copper wiring has been widely used. However, in the subtractive method, copper tends to remain at the bottom edge portion of the wiring, and if the wiring distance becomes short due to the higher density of the circuit wiring, there are problems such as short circuit, lack of insulation reliability between wirings, and the like. Further, if etching is further performed to prevent short-circuiting and improve insulation reliability, the etching solution may spread into the lower portion of the resist to cause undercut, resulting in a problem that the wiring width direction may be narrowed. In particular, when regions having different wiring densities are mixed together, there is a problem that fine wirings existing in a region having a low wiring density disappear if etching is performed. Further, the wiring obtained by the subtractive method has a cross-sectional shape that is not rectangular but is a trapezoid or triangle with a bottom edge that extends toward the substrate side, and thus has a problem as an electric transmission path because it is a wiring having a width that varies in the thickness direction.

As a method for manufacturing a fine wiring circuit to solve these problems, a half-additive method is proposed. In the semi-additive method, a conductive seed layer is formed on an insulating substrate in advance, and then a plating resist is formed on a non-circuit forming portion on the seed layer. After forming a wiring portion by electroplating through the conductive seed layer, the resist is stripped, and the seed layer of the non-circuit forming portion is removed, thereby forming a fine wiring. According to this method, since plating is deposited along the shape of the resist, the cross-sectional shape of the wiring can be made rectangular, and since the wiring of a target width can be deposited irrespective of the density of the pattern, the method is suitable for forming fine wiring.

In the semi-additive method, a method of forming a conductive seed layer on an insulating substrate by electroless copper plating or electroless nickel plating using a palladium catalyst is known. In these methods, for example, in the case of using a deposited film, in order to secure adhesion between a film substrate and a copper plating film, roughening of the surface of the substrate using a strong reagent such as permanganic acid, which is called desmear roughening, is performed, and a plating film is formed from the formed voids, whereby adhesion between an insulating substrate and the plating film is secured by an anchor effect. However, if the surface of the substrate is roughened, there are problems such as difficulty in forming fine wiring, and deterioration of high-frequency transmission characteristics. Therefore, the reduction of the degree of roughening has been studied, but in the case of low roughening, there is a problem that the required adhesion strength between the formed wiring and the substrate cannot be obtained.

On the other hand, a technique of forming a conductive seed crystal by electroless nickel plating on a polyimide film is also known. In this case, the polyimide film is immersed in a strong alkali to open the imide ring on the surface layer and hydrophilize the film surface, and a modified layer impregnated with water is formed, and a palladium catalyst is impregnated into the modified layer, whereby electroless nickel plating is performed to form a nickel seed layer (for example, see patent document 1.). In the present technique, nickel plating is formed from a modified layer of the polyimide outermost layer to obtain adhesion strength, but this modified layer is in a state in which an imide ring is opened, and therefore there is a problem that the film surface layer has a physically and chemically fragile structure.

On the other hand, as a method of forming a modified layer on a surface layer without roughening the surface, a method of forming a conductive seed crystal of nickel, titanium, or the like on an insulating substrate by a sputtering method is also known (for example, refer to patent document 2). This method can form a seed layer without roughening the surface of a substrate, but has the following problems: expensive vacuum equipment is required, huge initial investment is required, the size and shape of the base material are limited, and the procedures are complicated and the productivity is low.

As a method for solving the problem of the sputtering method, a method of using a coating layer of conductive ink containing metal particles as a conductive seed layer has been proposed (for example, see patent literature 3). In this technique, a technique is disclosed in which a conductive ink in which metal particles having a particle diameter of 1 to 500nm are dispersed is applied to an insulating substrate made of a film or sheet, and the metal particles in the applied conductive ink are fixed as a metal layer to the insulating substrate to form a conductive seed layer, and then the conductive seed layer is plated.

Patent document 3 proposes pattern formation by a semi-additive method, and in the examples, a substrate coated with a conductive ink in which copper particles are dispersed and heat-treated to form a conductive seed layer of copper is described as a substrate for the semi-additive method, a photosensitive resist is formed on the conductive seed layer, a pattern formation portion is thickened by exposure and development, the resist is peeled off, and then the conductive seed layer of copper is etched away. In addition, in the case of forming a printed wiring board by a semi-additive method, which has been studied conventionally, a substrate in which a thin copper foil or copper plating film is provided on an insulating substrate as a conductive seed crystal is used as a substrate for the semi-additive method.

As described above, in the case where the conductive seed layer of copper and the conductive layer of the circuit pattern are formed of the same metal as in the case of the combination of the conductive seed layer of copper and the circuit pattern of copper, it is known that the conductive layer of the circuit pattern is etched simultaneously when the conductive seed layer of the non-pattern-formed portion is removed, and therefore the circuit pattern becomes thin and thinner, and the surface roughness of the conductive layer of the circuit becomes large, which is a problem to be solved when manufacturing high-density wiring and high-frequency transmission wiring.

In order to solve these problems, the present inventors have invented a technique for forming a printed wiring board having a smooth circuit layer surface with excellent design reproducibility without thinning and thinning of a circuit pattern in a seed layer etching step by using a substrate having a conductive silver particle layer formed on the surface of an insulating substrate as a substrate for a semi-additive method. (non-patent document 1, 2)

This technique can form a circuit not only on one surface but also on both surfaces, but when a hole is formed in a substrate for a semi-additive method having conductive silver particle layers on both surfaces of an insulating substrate to connect the circuits on both surfaces, if a conventional two-surface electric connection step using a direct plating method is performed, the conductive silver particle layers are damaged and the conductivity is lowered in a microetching step for removing conductive substances such as palladium, conductive polymers, and carbon adsorbed on the conductive seed layer, and thus it is sometimes difficult to use as the conductive seed layer for forming a circuit pattern.

Prior art literature

Patent literature

Patent document 1: international publication No. 2009/004774;

patent document 2: japanese patent laid-open No. 9-136378;

patent document 3: japanese patent application laid-open No. 2010-272837;

non-patent document 1: village-Chuan Zhaozhao, profound constitution, fuji Chuan-Yi, white hair moist: "copper patterning technique using silver nanoparticle-based semi-additive process", the 28 th paper of the microelectronics seminar, pp285-288, 2018;

non-patent document 2: village Chuan Zhao, new Lin Zhaotai, deep constitution, fuji Chuan Zhao, white hair moist: "copper wiring formation by semi-additive method using silver as seed layer", the 33 rd electronic installation society, the spring lecture university sentence, 11B2-03, 2019.

Disclosure of Invention

Problems to be solved by the invention

The present invention provides a planar semi-additive laminate for double-sided connection which can form a wiring having a high adhesion between a substrate and a conductor circuit, less undercut, excellent design reproducibility, and a good rectangular cross-sectional shape as a circuit wiring without roughening the surface of the laminate by chromic acid or permanganic acid, forming a surface modified layer by alkali, and the like, and without using a vacuum device, and a printed wiring board using the same.

Means for solving the problems

The present inventors have made intensive studies to solve the above problems, and as a result, have found that a printed wiring board having high adhesion between a substrate and a conductor circuit, less undercut, and excellent design reproducibility can be formed without complicated surface roughening, without forming a surface-modified layer, and without using a vacuum device, by using a laminate in which a conductive silver particle layer (M1) and a releasable cover layer (RC) are laminated in this order on both surfaces of an insulating substrate (a), and the printed wiring board has a good rectangular cross-sectional shape as a circuit wiring, and have completed the present invention.

Namely, the present invention provides the following:

1. a laminate for a semi-additive method, which is a planar laminate for electrically connecting two surfaces of a substrate, characterized in that,

a conductive silver particle layer (M) and a releasable cover layer (RC) are laminated in this order on both surfaces of an insulating substrate (A).

2. The laminate for a semi-additive process according to claim 1, further comprising a primer layer (B) between the insulating substrate (A) and the silver particle layer (M).

3. The laminate for a semi-additive method according to 1 or 2, wherein the silver particles constituting the silver particle layer (M) are coated with a polymer dispersant.

4. The laminate for semi-addition method according to claim 3, wherein in the laminate for semi-addition method according to claim 2, the primer layer (B) is a layer composed of a resin having a reactive functional group [ X ], the polymer dispersant has a reactive functional group [ Y ], and the reactive functional group [ X ] and the reactive functional group [ Y ] can form a bond with each other by a reaction.

5. The laminate for a semi-additive process according to claim 4, wherein the reactive functional group [ Y ] is a basic nitrogen atom-containing group.

6. The laminate for a semi-additive process according to claim 5, wherein the polymer dispersant having the reactive functional group [ Y ] is at least 1 selected from the group consisting of polyalkyleneimines and polyalkyleneimines having a polyoxyalkylene structure containing an oxyethylene unit.

7. The laminate for a semi-additive process according to any one of claims 4 to 6, wherein the reactive functional group [ X ] is 1 or more selected from the group consisting of a ketone group, an acetoacetyl group, an epoxy group, a carboxyl group, an N-alkanol group, an isocyanate group, a vinyl group, a (meth) acryloyl group, and an allyl group.

8. A printed wiring board formed using the laminated body for a semi-additive method according to any one of 1 to 7.

9. A printed wiring board comprising a copper layer laminated on the silver particle layer (M1) of the laminated body for a semi-additive method according to any one of 1 to 7.

10. The method for manufacturing a printed wiring board according to claim 9, comprising:

step 1 of forming through holes penetrating both surfaces in a laminate having conductive silver particle layers (M) and Releasable Covers (RC) laminated in this order on both surfaces of an insulating substrate (A);

step 2 of imparting any one of palladium, a conductive polymer and carbon to the surface of the substrate having the through-holes to make the through-hole surface conductive;

step 3 of peeling the releasable coating layer (RC) to expose the conductive silver particle layer (M1);

step 4 of forming a pattern resist on the conductive silver particle layer (M1);

step 5 of electrically connecting both surfaces of the substrate by electroplating copper and forming a circuit pattern layer (M2);

and step 6 of stripping the pattern resist and removing the silver particle layer (M1) of the non-circuit pattern forming part by using an etching solution.

11. The method for manufacturing a printed wiring board according to claim 9, comprising:

step 2 of conducting electricity on the surface of the through-hole by performing any one of a vacuum vapor deposition method, an ion plating method, and a sputtering method on the surface of the substrate having the through-hole;

In addition, a preferred embodiment of the present invention provides a laminate for a semi-additive method and a printed wiring board using the laminate, wherein a primer layer (B) is further provided between the insulating base material layer (a) and the conductive silver particle layer (M1).

Effects of the invention

By using the laminate for a semi-additive method of the present invention, a printed wiring board having a smooth surface and a circuit wiring with a good rectangular cross-sectional shape, which is connected via both sides, can be produced with good design reproducibility without using a vacuum apparatus, and has high adhesion to various smooth substrates. Therefore, by using the technique of the present invention, a printed wiring board having a high density, high performance, and high frequency transmission capability, which is multilayered, can be provided at low cost, and the printed wiring board has high industrial applicability in the field of printed wiring. The printed wiring board produced using the laminate for a semi-additive method of the present invention can be used not only for a normal printed wiring board but also for various electronic components having a metal layer patterned on the surface of a substrate, for example, for a connector, an electromagnetic wave shield, an antenna such as an RFID, a film capacitor, and the like.

Drawings

FIG. 1 is a schematic view of a laminate for a semi-additive method according to claim 1.

Fig. 2 is a schematic view of a laminate for a semi-additive method having a primer layer on the silver particle layer of fig. 1 according to claim 2.

Fig. 3 is a process diagram of manufacturing a printed wiring board using the laminate for semi-additive method shown in fig. 1.

Detailed Description

The laminate for a semi-additive method is characterized in that a conductive silver particle layer (M1) and a releasable cover layer (RC) are laminated in this order on both surfaces of an insulating substrate (A).

A further preferred embodiment of the laminate for a semi-additive method according to the present invention is characterized in that: a primer layer (B) is further provided between the insulating base material layer (a) and the conductive silver particle layer (M1).

Examples of the material of the insulating base material (a) include: polyimide resins, polyamideimide resins, polyamide resins, polyethylene terephthalate resins, polybutylene terephthalate resins, polyethylene naphthalate resins, polycarbonate resins, acrylic resins such as acrylonitrile-butadiene-styrene (ABS) resins, polyarylate resins, polyacetal resins, polymethyl (meth) acrylate, polyvinylidene fluoride resins, polytetrafluoroethylene resins, polyvinyl chloride resins, polyvinylidene chloride resins, vinyl chloride resins having acrylic resins graft-copolymerized, polyvinyl alcohol resins, polyethylene resins, polypropylene resins, urethane resins, cycloolefin resins, polystyrene, liquid Crystal Polymers (LCP), polyetheretherketone (PEEK) resins, polyphenylene sulfide (PPS), polyphenylsulfone (PPSU), cellulose nanofibers, silicon carbide, gallium nitride, sapphire, ceramics, glass, diamond-like carbon (DLC), alumina, and the like.

As the insulating base material (a), a resin base material containing a thermosetting resin and an inorganic filler can be suitably used. Examples of the thermosetting resin include: epoxy resin, phenolic resin, unsaturated imide resin, cyanate resin, isocyanate resin, benzo

Oxazine resins, oxetane resins, amino resins, unsaturated polyester resins, allyl resins, dicyclopentadiene resins, silicone resins, triazine resins, melamine resins, and the like. On the other hand, examples of the inorganic filler include: silica, alumina, talc, mica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, aluminum borate, borosilicate glass, and the like. One kind of each of the thermosetting resin and the inorganic filler may be used, or two or more kinds may be used in combination.

As the form of the insulating base material (a), any of a planar flexible material, a rigid material, and a rigid and flexible material can be used. More specifically, the insulating base material (a) may be a commercially available material molded into a film, sheet or plate, or a material molded into a flat shape from a solution, melt or dispersion of the resin. The insulating base material (a) may be a base material in which the resin material is formed on a conductive material such as a metal, or may be a base material in which the resin material is laminated on a printed wiring board in which a circuit pattern is formed.

When a printed wiring board is manufactured using the laminate for a printed wiring board of the present invention, the silver particle layer (M1) serves as a plating base layer when a circuit pattern layer (M2) to be described later as a wiring pattern is formed by a plating process.

The silver particles constituting the silver particle layer (M1) may contain metal particles other than silver within a range in which a plating process to be described later can be normally performed, but the proportion of metal particles other than silver is preferably 5 parts by mass or less, more preferably 2 parts by mass or less, relative to 100 parts by mass of silver, from the viewpoint of further improving the etching removability of a non-circuit forming portion to be described later.

As a method of forming the silver particle layer (M1) on both surfaces of the planar insulating substrate (a), for example, a method of coating silver particle dispersion on both surfaces of the insulating substrate (a) may be mentioned. The method for coating the silver particle dispersion is not particularly limited as long as the silver particle layer (M1) can be formed well, and various coating methods can be appropriately selected depending on the shape, size, degree of hardness and softness of the insulating substrate (a) to be used, and the like. Specific coating methods include, for example: gravure, offset, flexo, pad, gravure, flexo, micro-contact, reverse, pneumatic blade, air knife, squeeze, dip, transfer roll, contact, cast, spray, ink jet, die, spin, rod, dip, and the like. In this case, the silver particle layer (M1) may be formed on both sides of the insulating substrate (a) at the same time, or may be formed on one side of the insulating substrate (a) and then formed on the other side.

For the purpose of improving the coating property of the silver particle dispersion and improving the adhesion of the circuit pattern layer (M2) formed in the plating step to the substrate, the insulating substrate (a) and the primer layer (B) formed on the insulating substrate (a) may be subjected to surface treatment before the silver particle dispersion is coated. The surface treatment method of the insulating substrate (a) is not particularly limited as long as the roughness of the surface is increased and the fine pitch patterning property and the signal transmission loss due to the rough surface are not a problem, and various methods may be appropriately selected. Examples of such a surface treatment method include: UV treatment, gas phase ozone treatment, liquid phase ozone treatment, corona treatment, plasma treatment, and the like. These surface treatment methods may be carried out by one method, or two or more methods may be used in combination.

After the silver particle dispersion is applied to the insulating substrate (a) or the primer layer (B), the coating film is dried, and the solvent contained in the silver particle dispersion volatilizes, whereby the silver particle layer (M1) is formed on the insulating substrate (a) or the primer layer (B).

The drying temperature and time are appropriately selected depending on the heat-resistant temperature of the base material to be used and the type of the solvent to be used in the metal particle dispersion liquid described later, and are preferably in the range of 20 to 350 ℃, and the time is preferably in the range of 1 to 200 minutes. In order to form a silver particle layer (M1) having excellent adhesion on a substrate, the drying temperature is more preferably in the range of 0 to 250 ℃.

The insulating substrate (a) on which the silver particle layer (M1) is formed or the insulating substrate (a) on which the primer layer (B) is formed may be further annealed after the drying as necessary for the purpose of reducing the resistance of the silver particle layer and improving the adhesion between the insulating substrate (a) or the primer layer (B) and the silver particle layer (M1). The temperature and time of annealing may be appropriately selected depending on the heat-resistant temperature of the substrate to be used, the desired resistance, productivity, etc., and may be in the range of 60 to 350 ℃ for 1 minute to 2 weeks. The time is preferably 1 minute to 2 weeks at a temperature range of 60 to 180 ℃, and is preferably about 1 minute to 5 hours at a temperature range of 180 to 350 ℃.

In the drying, the air blowing may be performed or may not be performed particularly. The drying may be performed in the atmosphere, under a substitution atmosphere of an inert gas such as nitrogen or argon, or under a gas flow, or under vacuum.

The drying of the coating film may be performed in a dryer such as a blower or a constant temperature dryer, in addition to the natural drying at the coating site. In the case where the insulating substrate (a) is a roll film or sheet, the roll material may be dried or fired by continuously moving the roll material in a non-heated or heated space provided after the coating step. Examples of the heating method for drying and baking at this time include a method using an oven, a hot air drying oven, an infrared drying oven, laser irradiation, microwaves, light irradiation (flash irradiation apparatus), and the like. These heating methods may be carried out by one kind, or two or more kinds may be used in combination.

The amount of the metal particle layer (M1) formed on the insulating substrate (A) or the primer layer (B) is preferably 0.01 to 30g/M ² More preferably 0.01 to 10g/m ² Is not limited in terms of the range of (a). In addition, the conductive layer (M3) is formed by a plating process described laterThe seed layer is preferably formed by etching, more preferably 0.05 to 5g/m, from the viewpoint of facilitating the formation and facilitating the seed layer removal step by etching described later ² Is not limited in terms of the range of (a).

The amount of the silver particle layer (M1) formed can be confirmed by a known and customary analytical method such as a fluorescent X-ray method, an atomic absorption method, and an ICP method.

In the step of exposing the circuit pattern to active light in the resist layer described later, for the purpose of suppressing reflection of the active light from the silver particle layer (M1), a light-absorbing pigment or dye such as graphite or carbon which absorbs the active light, a cyanine compound, a phthalocyanine compound, a dithiol metal complex, a naphthoquinone compound, a diimmonium compound, an azo compound, or the like may be contained in the silver particle layer (M1) as a light absorber within a range in which the silver particle layer (M1) can be formed, plating described later can be normally performed, and etching removability described later can be ensured. These pigments and coloring matters may be appropriately selected according to the wavelength of the active light to be used. One or two or more pigments may be used. Further, in order to contain these pigments and coloring matters in the silver particle layer (M1), these pigments and coloring matters may be blended in a silver particle dispersion liquid to be described later.

The silver particle dispersion for forming the silver particle layer (M1) is a dispersion of silver particles in a solvent. The shape of the silver particles is not particularly limited as long as the silver particle layer (M1) is favorably formed, and silver particles having various shapes such as spherical, lenticular, polyhedral, flat, rod-like, and linear can be used. The silver particles may be used in a single shape, or two or more different shapes may be used in combination.

When the silver particles are spherical or polyhedral, the average particle diameter is preferably in the range of 1 to 20,000 nm. In the case of forming a fine circuit pattern, the average particle diameter is more preferably in the range of 1 to 200nm, and even more preferably in the range of 1 to 50nm, from the viewpoint that the uniformity of the silver particle layer (M1) can be further improved and the removability by an etching solution, which will be described later, can be further improved. The "average particle diameter" of the nano-sized particles is a volume average value measured by a dynamic light scattering method by diluting the metal particles with a good dispersion solvent. In this measurement, "Nanotrac UPA-150" manufactured by MICROTRAC corporation may be used.

On the other hand, when the silver particles have a lens-like, rod-like, wire-like shape, etc., the short diameter thereof is preferably in the range of 1 to 200nm, more preferably in the range of 2 to 100nm, and even more preferably in the range of 5 to 50 nm.

The silver particles preferably contain silver particles as a main component, but as long as the plating step described later is not hindered or the removability of the silver particle layer (M1) described later by the etching liquid is not impaired, a part of silver constituting the silver particles may be replaced with another metal or a metal component other than silver may be mixed.

The metal to be substituted or mixed may be one or more metal elements selected from the group consisting of gold, platinum, palladium, ruthenium, tin, copper, nickel, iron, cobalt, titanium, indium, and iridium.

The ratio of the metal to be substituted or mixed with respect to the silver particles is preferably 5 mass% or less in the silver particles, and more preferably 2 mass% or less in view of the plating property of the silver particle layer (M1) and the removability by the etching solution.

The silver particle dispersion for forming the silver particle layer (M1) is obtained by dispersing silver particles in various solvents, and the particle size distribution of the silver particles in the dispersion may be uniform and monodisperse, or may be a mixture of particles having the average particle size range.

As the solvent used in the dispersion of silver particles, an aqueous medium or an organic solvent can be used. Examples of the aqueous medium include: distilled water, ion-exchanged water, pure water, ultrapure water, and a mixture of the above water and an organic solvent.

Examples of the organic solvent to be mixed with water include: alcohol solvents such as methanol, ethanol, n-propanol, isopropanol, ethyl carbitol, ethyl cellosolve, and butyl cellosolve; ketone solvents such as acetone and methyl ethyl ketone; alkylene glycol solvents such as ethylene glycol, diethylene glycol, and propylene glycol; polyalkylene glycol solvents such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol; lactam solvents such as N-methyl-2-pyrrolidone, and the like.

The organic solvent used alone may be an alcohol compound, an ether compound, an ester compound, or a ketone compound.

Examples of the alcohol solvent or ether solvent include: methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, heptanol, hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, stearyl alcohol, allyl alcohol, cyclohexanol, terpineol, dihydroterpineol, 2-ethyl-1, 3-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1, 2-butanediol, 1, 3-butanediol, 1, 4-butanediol, 2, 3-butanediol, glycerol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, and the like.

Examples of the ketone solvent include: acetone, cyclohexanone, methyl ethyl ketone, and the like. Examples of the ester solvent include: ethyl acetate, butyl acetate, 3-methoxybutyl acetate, 3-methoxy-3-methylbutyl acetate, and the like. Further, examples of the other organic solvent include hydrocarbon solvents such as toluene, and particularly hydrocarbon solvents having 8 or more carbon atoms.

Examples of the hydrocarbon solvent having 8 or more carbon atoms include nonpolar solvents such as octane, nonane, decane, dodecane, tridecane, tetradecane, cyclooctane, xylene, mesitylene, ethylbenzene, dodecylbenzene, tetrahydronaphthalene, and trimethylbenzene cyclohexane, and may be used in combination with other solvents as required. Further, a solvent such as mineral spirits and solvent naphtha may be used in combination as the mixed solvent.

The solvent is not particularly limited as long as it stably disperses the silver particles and the silver particle layer (M1) is favorably formed on the insulating substrate (a) or a primer layer (B) formed on the insulating substrate (a) described later. The solvent may be used alone or in combination of two or more.

Regarding the content of silver particles in the silver particle dispersion, the amount of the silver particle layer (M1) formed on the insulating substrate (A) is set to 0.01 to 30g/M by using the various coating methods ² The viscosity may be adjusted so as to have the best coating suitability for the various coating methods, and the range of the viscosity is preferably 0.1 to 50 mass%, more preferably 0.5 to 20 mass%.

The silver particle dispersion preferably contains a dispersing agent for dispersing the silver particles in the various solvents, and the silver particles preferably do not aggregate, fuse, or precipitate in the various solvents and maintain long-term dispersion stability. Such a dispersant is preferably a dispersant having a functional group coordinated to the metal particles, and examples thereof include dispersants having a functional group such as a carboxyl group, an amino group, a cyano group, an acetoacetyl group, a phosphorus atom-containing group, a thiol group, a thiocyanato group, and a glycine group.

As the dispersant, a commercially available or independently synthesized low-molecular-weight or high-molecular-weight dispersant may be used, and may be appropriately selected depending on the purpose of the solvent in which the metal particles are dispersed, the kind of the insulating substrate (a) to which the metal particle dispersion is applied, and the like. For example, it is possible to suitably use: dodecyl mercaptan, 1-octyl mercaptan, triphenylphosphine, dodecyl amine, polyethylene glycol, polyvinylpyrrolidone, polyethyleneimine, and polyvinylpyrrolidone; fatty acids such as myristic acid, caprylic acid, and stearic acid; and polycyclic hydrocarbon compounds having carboxyl groups such as cholic acid, glycyrrhizic acid and abietic acid. Here, in the case of forming the silver particle layer (M1) on the primer layer (B) described later, it is preferable to use a compound having a reactive functional group [ Y ] capable of forming a bond with the reactive functional group [ X ] of the resin used in the primer layer (B) described later, in terms of improving the adhesion of the 2 layers.

Examples of the compound having the reactive functional group [ Y ] include compounds having an amino group, an amide group, an alkanolamide group, a carboxyl group, a carboxylic anhydride group, a carbonyl group, an acetoacetyl group, an epoxy group, an alicyclic epoxy group, an oxetane ring, a vinyl group, an allyl group, a (meth) acryloyl group, a (blocked) isocyanate group, an (alkoxy) silyl group, and the like, and silsesquioxane compounds. In particular, the reactive functional group [ Y ] is preferably a basic nitrogen atom-containing group in view of further improving the adhesion between the primer layer (B) and the metal particle layer (M1). Examples of the basic nitrogen atom-containing group include: imino, primary amino, secondary amino, and the like.

The basic nitrogen atom-containing group may be present singly or in plural in the molecule of the dispersant 1. By containing a plurality of basic nitrogen atoms in the dispersant, a part of the basic nitrogen atom-containing groups contribute to the dispersion stability of the metal particles due to the interaction with the metal particles, and the remaining basic nitrogen atom-containing groups contribute to the improvement of the adhesion to the insulating substrate (a). In addition, when a resin having a reactive functional group [ X ] is used for the primer layer (B) described later, a basic nitrogen-containing group in the dispersant can form a bond with the reactive functional group [ X ], and adhesion of the circuit pattern layer (M2) described later to the insulating substrate (a) can be further improved, which is preferable.

The dispersing agent is preferably a polymer dispersing agent in terms of stability and coatability of the silver particle dispersion and the ability to form a silver particle layer (M1) exhibiting good adhesion on the insulating substrate (a), and the polymer dispersing agent is preferably a polyalkyleneimine such as polyethyleneimine or polypropyleneimine, a compound obtained by adding a polyoxyalkylene group to the polyalkyleneimine, or the like.

The compound obtained by adding a polyoxyalkylene group to the above-mentioned polyalkyleneimine may be a compound obtained by bonding a polyethyleneimine and a polyoxyalkylene group in a straight chain, or may be a compound obtained by grafting a polyoxyalkylene group to a main chain composed of the above-mentioned polyethyleneimine on a side chain thereof.

Specific examples of the compound obtained by adding a polyoxyalkylene group to the polyalkyleneimine include: a block copolymer of polyethylenimine and polyoxyethylene; a compound having a polyoxyethylene structure, wherein a part of an imino group present in a main chain of a polyethyleneimine is added to ethylene oxide; and a compound obtained by reacting an amino group of a polyalkyleneimine, a hydroxyl group of a polyoxyethylene glycol, and an epoxy group of an epoxy resin.

Examples of the commercial products of the polyalkyleneimines include "PAO2006W", "PAO306", "PAO318" and "PAO718" of "EPOMIN (registered trademark) PAO series" manufactured by Japanese catalyst, inc.

The number average molecular weight of the polyalkyleneimine is preferably in the range of 3,000 to 30,000.

The amount of the dispersant used for dispersing the silver particles is preferably in the range of 0.01 to 50 parts by mass based on 100 parts by mass of the silver particles, and is preferably in the range of 0.1 to 10 parts by mass based on 100 parts by mass of the silver particles, from the viewpoint of forming a silver particle layer (M1) exhibiting good adhesion on the insulating substrate (a) or a primer layer (B) described later, and from the viewpoint of improving the plating property of the silver particle layer (M1), and is more preferably in the range of 0.1 to 5 parts by mass.

The method for producing the silver particle dispersion is not particularly limited, and various methods can be used for producing the silver particle dispersion, and for example, silver particles produced by a vapor phase method such as a low vacuum vapor phase evaporation method may be dispersed in a solvent, or a silver compound may be reduced in a liquid phase to directly produce a silver particle dispersion. The solvent composition of the dispersion liquid at the time of production and the dispersion liquid at the time of coating can be changed by changing the solvent and adding the solvent as needed, as appropriate, in both the gas-phase and liquid-phase methods. Among the gas phase and liquid phase methods, the liquid phase method is particularly suitable from the viewpoints of stability of the dispersion and simplicity of the production process. As the liquid phase method, for example, silver ions can be reduced in the presence of the polymer dispersant.

The dispersion of silver particles may further contain, if necessary, an organic compound such as a surfactant, a leveling agent, a viscosity adjuster, a film-forming aid, a defoaming agent, or a preservative.

Examples of the surfactant include: nonionic surfactants such as polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene styrylphenyl ether, polyoxyethylene sorbitol tetraoleate, and polyoxyethylene-polyoxypropylene copolymer; anionic surfactants such as fatty acid salts such as sodium oleate, alkyl sulfate salts, alkylbenzene sulfonate salts, alkyl sulfosuccinate salts, naphthalene sulfonate salts, polyoxyethylene alkyl sulfate salts, sodium alkane sulfonate salts, and sodium alkyl diphenyl ether sulfonate salts; cationic surfactants such as alkylamine salts, alkyltrimethylammonium salts and alkyldimethylbenzyl ammonium salts.

As the leveling agent, a general leveling agent can be used, and examples thereof include: silicone compounds, acetylene glycol compounds, fluorine compounds, and the like.

As the viscosity modifier, a general thickener can be used, and examples thereof include: acrylic polymers which can be thickened by adjustment to alkaline, synthetic rubber latex, urethane resins which can be thickened by molecular association, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, polyvinyl alcohol, hydrogenated castor oil, amide wax, oxidized polyethylene, metal soaps, dibenzylidene sorbitol, and the like.

As the above-mentioned film forming auxiliary agent, general film forming auxiliary agents can be used, and examples thereof include: anionic surfactants such as dioctyl sulfosuccinate sodium salt, hydrophobic nonionic surfactants such as sorbitan monooleate, polyether modified silicone, silicone oil, and the like.

As the defoaming agent, a general defoaming agent can be used, and examples thereof include: silicone-based antifoaming agents, nonionic surfactants, polyethers, higher alcohols, polymer-based surfactants, and the like.

As the above-mentioned preservative, general ones can be used, and examples thereof include: isothiazoline-based preservatives, triazine-based preservatives, imidazole-based preservatives, pyridine-based preservatives, azole-based preservatives, pyrithione (pyrithione) -based preservatives, and the like.

In addition, as a more preferable mode of the laminate for a semi-additive method of the present invention, there is a laminate further comprising a primer layer (B) between the insulating base material layer (a) and the conductive silver particle layer (M1). The semi-additive laminate provided with the primer layer is preferable because the adhesion of the circuit pattern layer (M2) to the insulating substrate (a) can be further improved.

The primer layer (B) may be formed by coating a primer on a part or the entire surface of the insulating substrate (a), and removing a solvent such as an aqueous medium or an organic solvent contained in the primer. The primer is used for improving adhesion of the circuit pattern layer (M2) to the insulating substrate (a), and is a liquid composition obtained by dissolving or dispersing various resins described later in a solvent.

The method of applying the primer to the insulating substrate (a) is not particularly limited as long as the primer layer (B) can be formed satisfactorily, and various application methods may be appropriately selected depending on the shape, size, degree of hardness and flexibility of the insulating substrate (a) to be used. Specific examples of the coating method include: gravure, offset, flexo, pad, gravure, flexo, micro-contact, reverse, pneumatic blade, air knife, squeeze, dip, transfer roll, contact, cast, spray, ink jet, die, spin, rod, dip, and the like.

The method of applying the primer to both surfaces of the insulating substrate (a) in the form of a film, sheet or plate is not particularly limited as long as the primer layer (B) can be formed well, and the application method exemplified above may be appropriately selected. In this case, the primer layer (B) may be formed on both surfaces of the insulating substrate (a) at the same time, or may be formed on one surface of the insulating substrate (a) and then formed on the other surface.

The insulating substrate (a) may be subjected to surface treatment before the primer is applied for the purpose of improving the application property of the primer and improving the adhesion of the circuit pattern layer (M2) to the substrate. As the surface treatment method of the insulating substrate (a), the same method as that used in forming the silver particle layer (M1) on the insulating substrate (a) can be used.

As a method of forming the primer layer (B) by applying the primer to the surface of the insulating substrate (a) and then removing the solvent contained in the applied layer, for example, a method of drying the primer layer using a dryer to evaporate the solvent is generally used. The drying temperature may be set to a temperature in a range that allows the solvent to volatilize and does not adversely affect the insulating substrate (a), and may be room temperature drying or heat drying. The specific drying temperature is preferably in the range of 20 to 350 ℃, more preferably in the range of 60 to 300 ℃. The drying time is preferably in the range of 1 to 200 minutes, more preferably in the range of 1 to 60 minutes.

The drying may be performed by blowing or not particularly by blowing. The drying may be performed in the atmosphere, under a substitution atmosphere or a gas flow of nitrogen, argon, or the like, or under vacuum.

In the case where the insulating substrate (a) is a film, sheet or plate, the film, sheet or plate may be naturally dried at the application site or may be dried in a dryer such as a blower or a thermostatic dryer. In the case where the insulating substrate (a) is a roll film or a roll sheet, the roll material may be dried by continuously moving the roll material in a non-heated or heated space provided after the coating step.

The thickness of the primer layer (B) may be appropriately selected depending on the specifications and applications of the printed wiring board manufactured by using the present invention, and is preferably in the range of 10nm to 30 μm, more preferably in the range of 10nm to 1 μm, and even more preferably in the range of 10nm to 500nm, from the viewpoint of further improving the adhesion between the insulating substrate (a) and the circuit pattern layer (M2).

In the case where a substance having a reactive functional group [ Y ] is used as the dispersing agent for the metal particles, the resin forming the primer layer (B) is preferably a resin having a reactive functional group [ X ] reactive with the reactive functional group [ Y ]. Examples of the reactive functional group [ X ] include: amino, amido, alkanolamido, keto, carboxyl, carboxylic anhydride, carbonyl, acetoacetyl, epoxy, alicyclic epoxy, oxetane, vinyl, allyl, (meth) acryl, (blocked) isocyanate, (alkoxy) silyl, and the like. In addition, a silsesquioxane compound may be used as the compound forming the primer layer (B).

In particular, in the case where the reactive functional group [ Y ] in the dispersant is a basic nitrogen atom-containing group, the resin forming the primer layer (B) is preferably a resin having a ketone group, a carboxyl group, a carbonyl group, an acetoacetyl group, an epoxy group, an alicyclic epoxy group, an alkanolamide group, an isocyanate group, a vinyl group, a (meth) acryl group, or an allyl group as the reactive functional group [ X ] in view of further improving the adhesion of the conductive layer (M3) on the insulating substrate (a).

Examples of the resin for forming the primer layer (B) include: urethane resins, acrylic resins, core-shell type composite resins having a urethane resin as a shell and an acrylic resin as a core, epoxy resins, imide resins, amide resins, melamine resins, phenol resins, urea resins, blocked isocyanate polyvinyl alcohols obtained by reacting a blocking agent such as phenol with a polyisocyanate, polyvinyl pyrrolidone, and the like. The core-shell type composite resin having a urethane resin as a shell and an acrylic resin as a core can be obtained, for example, by polymerizing an acrylic monomer in the presence of the urethane resin. In addition, one kind of these resins may be used, or two or more kinds may be used in combination.

Among the resins for forming the primer layer (B), a resin that generates a reducing compound by heating is preferable in view of further improving the adhesion of the conductive layer (M3) to the insulating substrate (a). Examples of the reducing compound include: phenol compounds, aromatic amine compounds, sulfur compounds, phosphoric acid compounds, aldehyde compounds, and the like. Among these reducing compounds, phenol compounds and aldehyde compounds are preferable.

When a resin that generates a reducing compound by heating is used for the primer, a reducing compound such as formaldehyde or phenol is generated in the heat drying step when the primer layer (B) is formed. Specific examples of the resin that generates the reducing compound by heating include: a resin obtained by polymerizing a monomer containing an N-alkanol (meth) acrylamide, a core-shell type composite resin having a urethane resin as a shell and a resin obtained by polymerizing a monomer containing an N-alkanol (meth) acrylamide as a core, a urea-formaldehyde-methanol condensate, a urea-melamine-formaldehyde-methanol condensate, a formaldehyde adduct of a poly (N-alkoxymethylol (meth) acrylamide) or a poly (meth) acrylamide, a melamine resin, or the like, which generates formaldehyde by heating; phenolic resins, phenol blocked isocyanates, and the like, and resins that generate phenol compounds by heating. Among these resins, preferred are core-shell type composite resins having a urethane resin as a shell and a resin obtained by polymerizing a monomer containing an N-alkanol group (meth) acrylamide as a core, melamine resins, and phenol blocked isocyanates, from the viewpoint of improving adhesion.

In the present invention, "(meth) acrylamide" means one or both of "methacrylamide" and "acrylamide", and "(meth) acrylic acid" means one or both of "methacrylic acid" and "acrylic acid".

The resin which generates a reducing compound by heating can be obtained by polymerizing a monomer having a functional group which generates a reducing compound by heating by a polymerization method such as radical polymerization, anionic polymerization, cationic polymerization, or the like.

Examples of the monomer having a functional group which generates a reducing compound by heating include N-alkanol vinyl monomers, and specifically: n-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide, N-isopropoxymethyl (meth) acrylamide, N-N-butoxymethyl (meth) acrylamide, N-isobutoxymethyl (meth) acrylamide, N-pentoxymethyl (meth) acrylamide, N-ethanol (meth) acrylamide, N-propanol (meth) acrylamide, and the like.

In the production of the resin which generates a reducing compound by heating, various other monomers such as alkyl (meth) acrylate may be copolymerized together with a monomer having a functional group which generates a reducing compound by heating.

In the case of using the blocked isocyanate as the resin for forming the primer layer (B), the primer layer (B) is formed by forming an uretdione bond by self-reaction between isocyanate groups or by forming a bond between isocyanate groups and functional groups possessed by other components. The bond formed in this case may be formed before the metal particle dispersion is applied, or may be formed by heating after the metal particle dispersion is applied, instead of before the metal particle dispersion is applied.

Examples of the blocked isocyanate include those having a functional group formed by blocking an isocyanate group with a blocking agent.

The blocked isocyanate preferably has the above functional group in the range of 350 to 600g/mol per 1 mol of blocked isocyanate.

From the viewpoint of improving adhesion, the functional groups are preferably 1 to 10, more preferably 2 to 5, per 1 molecule of the blocked isocyanate.

The number average molecular weight of the blocked isocyanate is preferably in the range of 1,500 to 5,000, more preferably in the range of 1,500 to 3,000, from the viewpoint of improving adhesion.

Further, the blocked isocyanate preferably has an aromatic ring from the viewpoint of further improving adhesion. Examples of the aromatic ring include phenyl and naphthyl.

The blocked isocyanate can be produced by reacting a part or all of the isocyanate groups of the isocyanate compound with a blocking agent.

Examples of the isocyanate compound used as a raw material for the blocked isocyanate include: polyisocyanate compounds having an aromatic ring such as 4,4 '-diphenylmethane diisocyanate, 2,4' -diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, crude diphenylmethane diisocyanate, phenylene diisocyanate, toluene diisocyanate, naphthalene diisocyanate, etc.; aliphatic polyisocyanate compounds such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, and polyisocyanate compounds having an alicyclic structure. Further, the above polyisocyanate compounds may be exemplified by biuret, isocyanurate, and adduct thereof.

The isocyanate compound may be obtained by reacting the polyisocyanate compound exemplified above with a compound having a hydroxyl group or an amino group, or the like.

When an aromatic ring is introduced into the blocked isocyanate, a polyisocyanate compound having an aromatic ring is preferably used. Among the polyisocyanate compounds having an aromatic ring, 4 '-diphenylmethane diisocyanate, toluene diisocyanate, isocyanurate of 4,4' -diphenylmethane diisocyanate, and isocyanurate of toluene diisocyanate are preferable.

Examples of the blocking agent used for producing the blocked isocyanate include: phenol compounds such as phenol and cresol; lactam compounds such as epsilon-caprolactam, delta-valerolactam and gamma-butyrolactam; oxime compounds such as formamide oxime, aldoxime, acetone oxime, methyl ethyl ketoxime, methyl isobutyl ketoxime, and cyclohexanone oxime; 2-hydroxypyridine, butyl cellosolve, propylene glycol monomethyl ether, benzyl alcohol, methanol, ethanol, n-butanol, isobutanol, dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, butyl mercaptan, dodecyl mercaptan, acetanilide, acetamide, succinimide, maleimide, imidazole, 2-methylimidazole, urea, thiourea, ethyleneurea, diphenylaniline, aniline, carbazole, ethyleneimine, polyethyleneimine, 1H-pyrazole, 3-methylpyrazole, 3, 5-dimethylpyrazole, and the like. Among them, a blocking agent capable of dissociating and forming an isocyanate group by heating in the range of 70 to 200 ℃ is preferable, and a blocking agent capable of dissociating and forming an isocyanate group by heating in the range of 110 to 180 ℃ is more preferable. Specifically, phenol compounds, lactam compounds and oxime compounds are preferable, and particularly, phenol compounds are more preferable because they become reducing compounds when the capping agent is detached by heating.

Examples of the method for producing the blocked isocyanate include: a method of mixing and reacting the isocyanate compound produced in advance with the blocking agent; and a method in which the blocking agent is mixed with a raw material for producing the isocyanate compound and reacted.

More specifically, the above blocked isocyanate can be produced by: the polyisocyanate compound is reacted with a compound having a hydroxyl group or an amino group to thereby produce an isocyanate compound having an isocyanate group at the end, and then the isocyanate compound is mixed with the blocking agent and reacted.

The content ratio of the blocked isocyanate obtained by the above method in the resin forming the above primer layer (B) is preferably in the range of 50 to 100 mass%, more preferably in the range of 70 to 100 mass%.

Examples of the melamine resin include: mono-or poly-methylolmelamine obtained by adding 1 to 6 moles of formaldehyde to 1 mole of melamine; an etherate of (poly) methylolmelamine such as trimethoxymethylolmelamine, tributoxy methylolmelamine, or hexamethoxy methylolmelamine (the degree of etherification is arbitrary); urea-melamine-formaldehyde-methanol condensates and the like.

In addition, in addition to the method of using a resin that generates a reducing compound by heating as described above, a method of adding a reducing compound to a resin may be exemplified. In this case, examples of the reducing compound to be added include: phenolic antioxidants, aromatic amine antioxidants, sulfur antioxidants, phosphoric antioxidants, vitamin C, vitamin E, sodium ethylenediamine tetraacetate, sulfite, hypophosphorous acid, hypophosphite, hydrazine, formaldehyde, sodium borohydride, dimethylamine borane, phenol, and the like.

In the present invention, the method of adding a reducing compound to a resin may cause a decrease in electrical characteristics due to the final residual low molecular weight component or ionic compound, and therefore, a method of using a resin that generates a reducing compound by heating is more preferable.

The preferable resin for forming the primer layer (B) may be a resin containing a compound having an aminotriazine ring. The compound having an aminotriazine ring may be a low molecular weight compound or a higher molecular weight resin.

As the above-mentioned low molecular weight compound having an aminotriazine ring, various additives having an aminotriazine ring can be used. Examples of the commercial products include: 2, 4-diamino-6-vinyl s-triazine (VT manufactured by Kabushiki Kaisha), VD-3 (VD-4) (a compound having an aminotriazine ring and a hydroxyl group) manufactured by Kaisha, and VD-5 (a compound having an aminotriazine ring and an ethoxysilyl group) manufactured by Kaisha, etc. These compounds may be used as additives by adding one or two or more of the above-mentioned resins for forming the primer layer (B).

The amount of the low molecular weight compound having an aminotriazine ring used is preferably 0.1 part by mass or more and 50 parts by mass or less, more preferably 0.5 part by mass or more and 10 parts by mass or less, based on 100 parts by mass of the resin.

As the resin having an aminotriazine ring, a resin in which an aminotriazine ring is introduced into a polymer chain of the resin by a covalent bond can be suitably used. Specifically, an aminotriazine modified novolak resin can be exemplified.

The aminotriazine modified novolak resin is a novolak resin in which an aminotriazine ring structure and a phenol structure are bonded via a methylene group. The above aminotriazine modified novolak resin can be obtained, for example, by: co-condensation reaction of aminotriazine compounds such as melamine, benzoguanamine and acetoguanamine, phenol compounds such as phenol, cresol, butylphenol, bisphenol A, phenylphenol, naphthol and resorcinol, and formaldehyde in the presence or absence of a weakly basic catalyst such as alkylamine, in the vicinity of neutrality; or reacting an alkyl ether compound of an aminotriazine compound such as methylated melamine with the phenol compound.

The aminotriazine modified novolak resin preferably has substantially no hydroxymethyl group. The aminotriazine-modified novolak resin may contain a molecule having only an aminotriazine structure bound thereto and a molecule having only a phenol structure bound thereto, which are produced as by-products during production thereof. Further, a small amount of unreacted raw materials may be contained.

Examples of the phenol structure include: phenol residues, cresol residues, butylphenol residues, bisphenol a residues, phenylphenol residues, naphthol residues, resorcinol residues, and the like. In addition, the residue herein means a structure in which at least 1 hydrogen atom bonded to carbon of an aromatic ring is removed. For example, in the case of phenol, it means hydroxyphenyl.

Examples of the triazine structure include amino triazine compounds derived from melamine, benzoguanamine, acetoguanamine, and the like.

The phenol structure and the triazine structure may be used singly or in combination. In addition, from the viewpoint of further improving adhesion, the phenol structure is preferably a phenol residue, and the triazine structure is preferably a melamine-derived structure.

In order to further improve the adhesion, the hydroxyl value of the aminotriazine modified novolak resin is preferably 50mgKOH/g or more and 200mgKOH/g or less, more preferably 80mgKOH/g or more and 180mgKOH/g or less, and still more preferably 100mgKOH/g or more and 150mgKOH/g or less.

The aminotriazine-modified novolak resin may be used singly or in combination.

In the case of using an aminotriazine modified novolak resin as the compound having an aminotriazine ring, it is preferable to use an epoxy resin in combination.

Examples of the epoxy resin include: bisphenol a type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, cresol novolak type epoxy resin, phenol novolak type epoxy resin, bisphenol a novolak type epoxy resin, alcohol ether type epoxy resin, tetrabromobisphenol a type epoxy resin, naphthalene type epoxy resin, phosphorus-containing epoxy compound having a structure derived from 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide derivative, epoxy resin having a structure derived from dicyclopentadiene derivative, epoxy of oil and fat such as epoxidized soybean oil, and the like. One kind of these epoxy resins may be used, or two or more kinds may be used in combination.

Among the above epoxy resins, bisphenol a type epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins, cresol novolac type epoxy resins, phenol novolac type epoxy resins, bisphenol a novolac type epoxy resins are preferable, and bisphenol a type epoxy resins are particularly preferable, in view of further improving the adhesion.

In order to further improve the adhesion, the epoxy equivalent of the epoxy resin is preferably 100 g/equivalent to 300 g/equivalent, more preferably 120 g/equivalent to 250 g/equivalent, and still more preferably 150 g/equivalent to 200 g/equivalent.

In the case where the primer layer (B) is a layer containing an aminotriazine modified novolak resin and an epoxy resin, the molar ratio [ (x)/(y) ] of the phenolic hydroxyl group (x) in the aminotriazine modified novolak resin to the epoxy group (y) in the epoxy resin is preferably 0.1 to 5, more preferably 0.2 to 3, still more preferably 0.3 to 2, in view of further improving the adhesion.

When a layer containing an aminotriazine modified novolak resin and an epoxy resin is formed as the primer layer (B), a primer resin composition containing the compound having an aminotriazine ring and an epoxy resin is used.

Further, other resins such as urethane resins, acrylic resins, blocked isocyanate resins, melamine resins, and phenolic resins may be optionally blended into the primer resin composition for forming the primer layer (B) containing the aminotriazine modified novolak resin and the epoxy resin. These other resins may be used singly or in combination.

The primer used for forming the primer layer (B) preferably contains 1 to 70 mass% of the resin in the primer, more preferably 1 to 20 mass% in view of coatability and film-forming property.

Examples of the solvent that can be used for the primer include various organic solvents and aqueous media. Examples of the organic solvent include toluene, ethyl acetate, methyl ethyl ketone, and cyclohexanone, and examples of the aqueous medium include water, an organic solvent mixed with water, and a mixture thereof.

In addition, the resin forming the primer layer (B) may have, for example, an alkoxysilyl group, a silanol group, a hydroxyl group, an amino group, or the like, which contributes to a crosslinking reaction, as required. The crosslinked structure formed by these functional groups may be formed before the step of forming the silver particle layer (M1) in the subsequent step, or may be formed after the step of forming the silver particle layer (M1). When the crosslinked structure is formed after the step of forming the silver particle layer (M1), the crosslinked structure may be formed in advance in the primer layer (B) before the circuit pattern layer (M2) is formed, or may be formed in the primer layer (B) by curing, for example, after the circuit pattern layer (M2) is formed.

The primer layer (B) may be optionally added with a known substance such as a pH adjuster including a crosslinking agent, a film forming aid, a leveling agent, a thickener, a water repellent, and an antifoaming agent.

Examples of the crosslinking agent include metal chelate compounds, polyamine compounds, aziridine compounds, metal salt compounds, isocyanate compounds, and the like, and examples thereof include thermal crosslinking agents, melamine compounds, epoxy compounds, and the like which react at a relatively low temperature of about 25 to 100℃to form a crosslinked structure,

The heat crosslinking agent and various photocrosslinkers are formed by reacting an oxazoline compound, a carbodiimide compound, a blocked isocyanate compound, or the like at a relatively high temperature of 100 ℃ or higher to form a crosslinked structure. In the case of using the above aminotriazine modified novolak resin and the epoxy resin as the above primer layer (B), it is preferable to use a polycarboxylic acid as the above crosslinking agent in the primer resin composition. Examples of the polycarboxylic acid include trimellitic anhydride, pyromellitic anhydride, maleic anhydride, and succinic acid. These crosslinking agents may be used singly or in combination. Among these crosslinking agents, trimellitic anhydride is preferable in view of further improving adhesion.

The amount of the crosslinking agent used varies depending on the type, but is preferably in the range of 0.01 to 60 parts by mass, more preferably in the range of 0.1 to 10 parts by mass, and even more preferably in the range of 0.1 to 5 parts by mass, relative to 100 parts by mass of the total resin contained in the primer, from the viewpoint of improving the adhesion of the circuit pattern layer (M2) to the substrate.

In the case of using the above-mentioned crosslinking agent, the crosslinked structure may be formed before the step of forming the silver particle layer (M1) in the subsequent step, or the crosslinked structure may be formed after the step of forming the silver particle layer (M1). In the case where the crosslinked structure is formed after the step of forming the silver particle layer (M1), the crosslinked structure may be formed in the primer layer (B) before the circuit pattern layer (M2) is formed, or the crosslinked structure may be formed in the primer layer (B) after the circuit pattern layer (M2) is formed, for example, by aging.

In the present invention, the method of forming the silver particle layer (M1) on the primer layer (B) is the same as the method of forming the silver particle layer (M1) on the insulating substrate (a).

In addition, the primer layer (B) may be surface-treated before the silver particle dispersion is applied, in the same manner as the insulating substrate (a), for the purpose of improving the application of the silver particle dispersion and improving the adhesion of the circuit pattern layer (M2) to the substrate.

The laminate for the semi-additive method of the present invention is a laminate obtained by laminating a releasable coating layer (RC) on the silver particle layer (M1).

In the method for producing a printed wiring board of the present invention, by stacking the releasable coating layer (RC) on the silver particle layer (M1), in the step of forming through holes penetrating both surfaces, which will be described later, adhesion of generated organic and inorganic chips (gumming residues) to the surface of the silver particle layer (M1) is prevented, and in the step of making the inner wall surface of the formed through holes conductive, adhesion of any one of palladium, conductive polymer and carbon to the conductive silver particle layer (M1) is prevented, thereby protecting the silver particle layer (M1).

As a material of the releasable cover layer (RC), there is no particular limitation as long as the purpose of protecting the conductive silver particle layer (M1) can be achieved in a pretreatment step which is a step of using a conductive seed for electrolytic copper plating for forming the circuit pattern layer (M2) described later in the method for producing a printed wiring board of the present invention, and various commercially available resin films can be used, and films of polyethylene, polypropylene, and polyethylene terephthalate can be suitably used.

The releasable cover layer (RC) may be a film having a silicone layer for improving the releasability on a film of polyethylene, polypropylene, polyethylene terephthalate, or the like.

The thickness of the releasable coating layer (RC) used in the present invention is preferably 10 to 100. Mu.m, more preferably 15 to 70. Mu.m, from the viewpoints of the handling properties of the film, the protective properties of the silver particle layer (M1), and the ease of forming through holes in the substrate.

The releasable coating layer (RC) used in the present invention may be laminated on the silver particle layer (M1) after the silver particle layer (M1) is coated. For example, when the silver particle layer (M1) is coated by a roll coater, the releasable coating layer (RC) can be laminated by being wound together at the time of winding.

As a raw material of the above-described releasable coating layer (RC) of the present invention, an alkali-soluble resin may also be used. The alkali-soluble resin is not particularly limited as long as it can be developed in an alkali developer, and any known and customary alkali-soluble resin can be used, and examples thereof include an amide imide resin and a resin having an alkali-soluble functional group such as a carboxyl group or a phenolic hydroxyl group. The alkali-soluble resin may be formed by applying a resin solution to the silver particle layer (M1), or a resin having been previously formed into a film may be used. When a film-formed resin is used, for example, the silver particle layer (M1) can be coated by a roll coater as described above, and the release coating layer (RC) can be wound together at the time of winding to laminate the layers.

A process 1 of the method for manufacturing a printed wiring board using the laminate for a semi-additive method of the present invention is a process comprising: a half-additive layered product in which a silver particle layer (M1) and a releasable cover film (RC) are layered in this order on both surfaces of an insulating substrate (A), or a half-additive layered product in which a primer layer (B) is further layered between the insulating substrate (A) and the silver particle layer (M1), is formed to have through holes penetrating both surfaces.

In step 1, the method of forming the through-hole in the laminate for the half-additive method may be, for example, a method in which a known and customary method is appropriately selected. Methods such as drill processing, laser processing, and processing methods in which laser processing is combined with reagent etching of an insulating substrate using an oxidizing agent, an alkaline agent, an acidic agent, or the like.

The pore diameter (diameter) of the pores formed in the pore-forming process is preferably in the range of 0.01 to 1mm, more preferably in the range of 0.02 to 0.5mm, and even more preferably in the range of 0.03 to 0.1 mm.

Since organic and inorganic scraps (smears) generated during the hole forming process may cause poor plating deposition, reduced plating adhesion, and impaired plating appearance in the plating step for electrically connecting both surfaces and forming the conductive layer (M3), the scraps (desmear) are preferably removed. Examples of the method for removing the gum residue include: dry treatment such as plasma treatment and anti-sputtering treatment, wet treatment such as cleaning treatment with an aqueous solution of an oxidizing agent such as potassium permanganate, cleaning treatment with an aqueous solution of an alkali or an acid, and cleaning treatment with an organic solvent.

Step 2 of the method for manufacturing a printed wiring board using the laminate for a semi-additive method of the present invention is a step of: the surface of the laminate having the through-holes formed in the step 1 is provided with any one of palladium, a conductive polymer and carbon to make the through-hole surface conductive.

As a method for making the surface of the through-hole conductive, for example, a method described as "direct plating method" in Feng Yongshi, circuit technology, vol.8, no.1 (1993), pp.47-59 can be referred to.

As a method for making the surface of the through-hole conductive, any of the four types of (1) palladium-tin colloid system, (2) tin-free palladium system, (3) conductive polymer system, and (4) graphite system described in the above-mentioned document may be used.

As a method for conducting the surface of the through-hole using a palladium-tin colloid, a cleaning agent-conditioner (cleaner-conditioner) treatment is performed on the surface of the laminate having the through-hole formed therein, and then the surface is adsorbed with a tin-palladium colloid, and then a promoter (accelerator) treatment is performed to remove tin. In addition, a method of further converting palladium into palladium sulfide to improve conductivity may be used.

As a method for conducting electricity to the surface of the through-hole by using the conductive polymer, a method of oxidatively polymerizing a monomer of a pyrrole derivative can be used. Treating the surface of the laminate having the through-holes formed therein with a conditioner, and then treating the laminate with an aqueous permanganate solution to form MnO on the surface of the through-holes formed in the insulating substrate (A) ₂ . When the substrate surface is immersed in an aqueous monomer solution containing a high boiling point alcohol and then immersed in a dilute sulfuric acid aqueous solution, the substrate surface is treated with MnO ₂ The coated surface is polymerized to form a conductive polymer, thereby conducting electricity.

Further, as a method of making the surface of the through-hole conductive by graphite, the surface of the substrate for the semi-additive process in which the through-hole is formed may be treated with a suspended carbon black solution, and carbon may be adsorbed on the entire surface of the substrate. By treating the surface of the laminate having the through-holes formed therein with a conditioning agent, the surface of the substrate is positively charged, and thereafter negatively charged carbon black is adsorbed on the surface, whereby conductivity can be ensured.

As a method for making the surface of the through-hole conductive, any of the methods using palladium, conductive polymer and carbon described above may be used, and a commercially available known and customary process may be used. For example, in the tin-palladium process, a method known as a CRIMSON process may be used, and in the graphite system, for example, a process known as a black hole process may be used. Among these methods, a method of conducting electricity with carbon is preferably used from the viewpoints of materials and process costs.

Further, as a method of making the surface of the through-hole conductive, the following method may be suitably used: the laminate having the through-holes formed in the step 1 is formed by a dry plating method, for example, a vacuum deposition method, an ion plating method, or a sputtering method, and is electrically conductive by forming a film on the surfaces of the through-holes. In the case of conducting electricity by a dry plating method, the metal species used for conducting electricity is not particularly limited as long as it can conduct electricity on the surface of the through hole and does not interfere with the connection of both surfaces by electroplating copper in the subsequent step, and various metals and metal oxides may be used, for example, one or a combination of metals such as titanium, nickel, copper, silver, gold, and platinum may be used. When a plurality of metals are combined, the plurality of metals may be formed simultaneously or sequentially. Among these metal species, copper or silver is preferably used from the viewpoint of conductivity.

Step 3 of the method for manufacturing a printed wiring board using the laminate for a semi-additive method of the present invention is a step of: the releasable coating layer (RC) is released to expose the conductive silver particle layer (M1). The present step is a step of exposing the conductive silver particle layer (M1) as a plating seed layer for forming the conductive layer (M3) in the subsequent step, and has the purpose of removing palladium, conductive polymer, carbon, sputtered metal, or metal oxide for making the through-holes conductive in step 2 from the surface other than the through-holes.

The peeling of the releasable coating layer (RC) in step 3 may be performed mechanically, and various commercially available peeling apparatuses may be used. In the case of using an alkali-soluble resin as the releasable coating layer (RC), the release can be performed by immersing in an alkali solution. As the alkaline solution and the stripping conditions used in the stripping, a stripping solution for pattern resist described later can be suitably used.

In step 4 of the method for producing a printed wiring board using the laminate for a semi-additive method of the present invention, a pattern resist for a circuit pattern is formed on the silver particle layer (M1) exposed in step 3.

In the step of forming the pattern resist of step 4, the surface of the silver particle layer (M1) may be subjected to surface treatments such as a cleaning treatment with an acidic or alkaline cleaning liquid, a corona treatment, a plasma treatment, a UV treatment, a gas-phase ozone treatment, a liquid-phase ozone treatment, and a treatment with a surface treatment agent before forming the resist, for the purpose of improving adhesion to the resist layer. These surface treatments may be carried out by one method, or two or more methods may be used in combination.

As the treatment with the surface treatment agent, for example, the following method can be used: a method of treating with an anticorrosive agent comprising a triazole-based compound, a silane coupling agent and an organic acid as described in JP-A-7-258870; a method of treating with an organic acid, a benzotriazole-based rust inhibitor and a silane coupling agent as described in JP-A-2000-286546; a method of treating a substance having a structure in which a nitrogen-containing heterocycle such as triazole or thiadiazole is bonded to a silyl group such as trimethoxysilyl or triethoxysilyl via an organic group such as a sulfide (sulfide) bond, as described in JP-A2002-363189; a method of treating with a silane compound having a triazine ring and an amino group described in WO 2013/186941; a method of treating an imidazole silane compound obtained by reacting a formylimidazole compound with an aminopropyl silane compound as described in Japanese patent application laid-open No. 2015-214743; a method of treating with an oxazolidine compound as described in Japanese patent application laid-open No. 2016-134454; a method of treating an aromatic compound having an amino group and an aromatic ring in one molecule, a polybasic acid having 2 or more carboxyl groups, and a solution containing a halide ion as described in JP-A2017-203073; a method of treating with a surface treating agent containing a triazole silane compound described in Japanese patent application laid-open No. 2018-16865.

In order to form a metal pattern on the surface of the laminate for the semi-additive method of the present invention, the photosensitive resist is exposed to active light through a photomask or by using a direct exposure machine. The exposure amount may be appropriately set as needed. The latent image formed on the photosensitive resist by exposure is removed using a developer, thereby forming a pattern resist.

The developer may be, for example, a dilute aqueous alkali solution such as sodium carbonate or potassium carbonate in an amount of 0.3 to 2% by mass. To the above-mentioned diluted alkaline aqueous solution, a surfactant, an antifoaming agent, a small amount of an organic solvent for promoting development, and the like may be added. The exposed substrate is immersed in a developer or the developer is sprayed onto a resist by a sprayer or the like to develop, and the patterned resist with the pattern formed portion removed can be formed by the development.

In forming a patterned resist, a resist residue such as a skirt portion generated at a boundary portion between a cured resist and a substrate, and a resist deposit remaining on a surface of the substrate may be removed by a desmear treatment using plasma or a commercially available resist residue remover.

As the photosensitive resist used in the present invention, commercially available resist ink, liquid resist, dry film resist can be used, and they may be appropriately selected depending on the resolution of the target pattern, the type of the exposure machine used, the type of the reagent used in the plating process in the subsequent step, pH, and the like.

Examples of the commercially available resist ink include: "plating resist MA-830" and "etching resist X-87" manufactured by solar ink manufacturing Co., ltd; etching resist, plating resist of NAZDAR company; the "etching resist PLAS FINE PER" series manufactured by the company of the interactive chemical industry, the "plating resist PLAS FINE PPR" series, and the like. Examples of the electrodeposition resist include "Eagle series" and "Pepper series" of Dow Chemical Company. Further, examples of the dry film that is commercially available include: "Photoc" series manufactured by Hitachi chemical Co., ltd; "ALPHO" series manufactured by Nikko-Materials Co., ltd; the "Sunfort" series manufactured by Asahi chemical Co., ltd., the "Riston" series manufactured by Dupont, etc.

In order to efficiently manufacture a printed wiring board, it is convenient to use a dry film resist, and particularly in the case of forming a fine circuit, a dry film for a half-additive method may be used. As a commercially available dry film for this purpose, for example, there can be used: "ALFO LDF500", "NIT2700", manufactured by Nikko-Materials, xudi chemical Co., ltd., "Sunfort UFG-258", manufactured by Hitachi chemical Co., ltd., "RD series (RD-2015, 1225)", "RY series (RY-5319, 5325)", and "PlateMaster series (PM 200, 300)", manufactured by Dupont, etc.

In step 5 of the method for manufacturing a printed wiring board according to the present invention, the conductive silver particle layer (M1) is used as a cathode electrode for copper plating, and the copper plating process is performed on the silver particle layer (M1) exposed by development in the above-described operation, whereby the through-holes of the laminate can be connected by copper plating, and the circuit pattern layer (M2) is formed.

The surface of the silver particle layer (M1) may be optionally subjected to a surface treatment before the circuit pattern layer (M2) is formed by the electrolytic copper plating method. The surface treatment may be, for example, a cleaning treatment with an acidic or alkaline cleaning liquid, a corona treatment, a plasma treatment, a UV treatment, a gas-phase ozone treatment, a liquid-phase ozone treatment, or a treatment with a surface treatment agent under the condition that the surface of the silver particle layer (M1) and the formed resist pattern are not damaged. These surface treatments may be carried out by one method, or two or more methods may be used in combination.

When the circuit pattern layer (M2) is formed on the insulating substrate using the laminate for a semi-additive method of the present invention, annealing may be performed after plating for the purpose of relaxing the stress of the plating film and improving the adhesion. The annealing may be performed before or after the etching step described later, or may be performed before or after the etching step.

The annealing temperature may be appropriately selected in the temperature range of 40 to 300 ℃ depending on the heat resistance of the substrate to be used and the purpose of use, and is preferably in the range of 40 to 250 ℃, and more preferably in the range of 40 to 200 ℃ from the viewpoint of suppressing oxidation degradation of the plating film. In the case of a temperature range of 40 to 200 ℃, the annealing time may be 10 minutes to 10 days, and the annealing at a temperature exceeding 200 ℃ may be about 5 minutes to 10 hours. In addition, when annealing the plating film, an antirust agent can be appropriately given to the surface of the plating film.

In step 6 of the method for manufacturing a printed wiring board according to the present invention, after the circuit pattern layer (M2) is formed by plating in step 5, the pattern resist formed using the photosensitive resist is peeled off, and the silver particle layer (M1) in the non-pattern-formed portion is removed by an etching solution. The pattern resist may be removed under recommended conditions described in the catalogue, specification, and the like of the photosensitive resist to be used. As a resist stripping solution used for stripping the pattern resist, a commercially available resist stripping solution, or a 1.5 to 3 mass% aqueous solution of sodium hydroxide or potassium hydroxide at 45 to 60 ℃ can be used. The resist may be removed by immersing the substrate on which the circuit pattern layer (M2) is formed in a stripping liquid, or spraying the stripping liquid with a sprayer or the like.

In addition, the etching solution used for removing the silver particle layer (M1) in the non-pattern-formed portion preferably etches only the silver particle layer (M1) selectively, and does not etch copper forming the conductive layer (M3). As such an etching liquid, a mixture of carboxylic acid and hydrogen peroxide can be exemplified.

Examples of the carboxylic acid include: acetic acid, formic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, oxalic acid, malonic acid, succinic acid, benzoic acid, salicylic acid, phthalic acid, isophthalic acid, terephthalic acid, gallic acid, mellitic acid, sarcosilicic acid, pyruvic acid, lactic acid, malic acid, citric acid, fumaric acid, maleic acid, aconitic acid, glutaric acid, adipic acid, amino acids, and the like. These carboxylic acids may be used singly or in combination. Among these carboxylic acids, acetic acid is preferably mainly used in view of ease of production and handling as an etching solution.

If a mixture of carboxylic acid and hydrogen peroxide is used as the etching liquid, peroxycarboxylic acid (peroxycarboxylic acid) is formed by the reaction of hydrogen peroxide and carboxylic acid. It is presumed that the generated peroxycarboxylic acid suppresses the dissolution of copper constituting the circuit pattern layer (M2) and preferentially dissolves silver constituting the silver particle layer (M1).

The mixing ratio of the mixture of the carboxylic acid and hydrogen peroxide is preferably in the range of 2 to 100 moles, more preferably in the range of 2 to 50 moles, per 1 mole of the carboxylic acid, from the viewpoint of suppressing dissolution of the copper circuit pattern layer (M2).

The mixture of the carboxylic acid and hydrogen peroxide is preferably an aqueous solution diluted with water. In addition, the content ratio of the mixture of the carboxylic acid and hydrogen peroxide in the aqueous solution is preferably in the range of 2 to 65 mass%, more preferably in the range of 2 to 30 mass%, from the viewpoint of suppressing the influence of the temperature rise of the etching solution.

As the water for dilution, water from which ionic substances and impurities are removed, such as ion exchange water, pure water, and ultrapure water, is preferably used.

A protective agent for protecting the copper circuit pattern layer (M2) to inhibit dissolution may be further added to the etching solution. As the protective agent, an azole compound is preferably used.

Examples of the azole compound include: imidazole, pyrazole, triazole, tetrazole,

Oxazole, thiazole, selenazole,>

diazole, thiadiazole, ">

Triazole, thiatriazole, and the like.

Specific examples of the azole compound include: 2-methylbenzimidazole, aminotriazole, 1,2, 3-benzotriazole, 4-aminobenzotriazole, 1-bisaminomethylbenzotriazole, aminotetrazole, phenyltetrazole, 2-phenylthiazole, benzothiazole and the like. One kind of these azole compounds may be used, or two or more kinds may be used in combination.

The concentration of the azole compound in the etching solution is preferably in the range of 0.001 to 2 mass%, more preferably in the range of 0.01 to 0.2 mass%.

In addition, in the etching solution, polyalkylene glycol is preferably added as a protective agent in order to suppress dissolution of the copper circuit pattern layer (M2).

Examples of the polyalkylene glycol include water-soluble polymers such as polyethylene glycol, polypropylene glycol, and polyoxyethylene polyoxypropylene block copolymers. Among them, polyethylene glycol is preferable. The number average molecular weight of the polyalkylene glycol is preferably in the range of 200 to 20,000.

The concentration of the polyalkylene glycol in the etching solution is preferably in the range of 0.001 to 2 mass%, more preferably in the range of 0.01 to 1 mass%.

The etching solution may be optionally blended with an additive such as sodium salt, potassium salt, ammonium salt of an organic acid to suppress pH fluctuation.

In the laminate for a semi-additive method of the present invention, removal of the silver particle layer (M1) of the non-pattern-formed portion can be performed by: after the circuit pattern layer (M2) is formed, the pattern resist formed using the photosensitive resist is peeled off, and the peeled substrate is immersed in the etching solution or the etching solution is sprayed on the substrate by a sprayer or the like.

When the silver particle layer (M1) of the non-pattern-formed portion is removed by using an etching apparatus, for example, the etching apparatus may be supplied with the etching liquid so that all components of the etching liquid have a predetermined composition, or the etching liquid may be supplied with each component separately to the etching apparatus, and the etching liquid may be prepared so that the components are mixed in the apparatus to have a predetermined composition.

The etching solution is preferably used at a temperature of 10 to 35 ℃, and particularly when an etching solution containing hydrogen peroxide is used, the etching solution is preferably used at a temperature of 30 ℃ or less in view of suppressing decomposition of hydrogen peroxide.

As described above, the printed wiring board of the present invention can be manufactured by performing the following steps:

step 5 of forming a conductive layer (M3) of the circuit pattern by electrically connecting both surfaces of the base material by electroplating copper; and

After the silver particle layer (M1) is removed by the etching liquid, a cleaning operation may be further performed in addition to the water washing in order to prevent the silver component dissolved in the etching liquid from adhering to and remaining on the printed wiring board. In the cleaning operation, a cleaning solution in which silver oxide, silver sulfide, silver chloride are dissolved but silver is hardly dissolved is preferably used. Specifically, it is preferable to use an aqueous solution containing thiosulfate or tris (3-hydroxyalkyl) phosphine, or an aqueous solution containing mercapto carboxylic acid or a salt thereof as the cleaning agent.

Examples of the thiosulfate include: ammonium thiosulfate, sodium thiosulfate, potassium thiosulfate, and the like. Examples of the tris (3-hydroxyalkyl) phosphine include: tris (3-hydroxymethyl) phosphine, tris (3-hydroxyethyl) phosphine, tris (3-hydroxypropyl) phosphine, and the like. One or two or more of these thiosulfate or tris (3-hydroxyalkyl) phosphine may be used each.

The concentration of the thiosulfate-containing aqueous solution to be used may be appropriately set depending on the process time, the characteristics of the cleaning apparatus to be used, and the like, and is preferably in the range of 0.1 to 40 mass%, and more preferably in the range of 1 to 30 mass% from the viewpoints of cleaning efficiency and stability of the reagent in continuous use.

The concentration of the aqueous solution containing the tris (3-hydroxyalkyl) phosphine may be appropriately set depending on the process time, the characteristics of the cleaning apparatus used, and the like, and is preferably in the range of 0.1 to 50 mass%, more preferably in the range of 1 to 40 mass% from the viewpoints of cleaning efficiency and stability of the reagent in continuous use.

Examples of the above mercapto carboxylic acid include: thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, cysteine, N-acetylcysteine, and the like. Examples of the salts of the above mercapto carboxylic acids include: alkali metal salts, ammonium salts, amine salts, and the like.

The concentration of the aqueous solution of the mercapto carboxylic acid or its salt is preferably in the range of 0.1 to 20 mass%, and more preferably in the range of 0.5 to 15 mass% from the viewpoints of cleaning efficiency and process cost in performing a large amount of treatment.

As a method for performing the above-described cleaning operation, for example, there may be mentioned: a method of immersing the printed wiring board obtained by etching the silver particle layer (M1) from which the non-pattern-formed portion is removed in the cleaning agent; a method of spraying a cleaning agent onto the printed wiring board using a sprayer or the like. The temperature of the cleaning agent may be used at room temperature (25 ℃), but in view of stably performing the cleaning process without being affected by the outdoor air temperature, for example, the temperature may be set to 30 ℃.

The step of removing the silver particle layer (M1) in the non-pattern-formed portion with the etching solution and the cleaning operation may be repeated as necessary.

As described above, the printed wiring board of the present invention may further perform a cleaning operation as needed to further improve the insulation properties of the non-pattern-formed portion after removing the silver particle layer (M1) of the non-pattern-formed portion by the etching liquid. In this washing operation, for example, an alkaline permanganate solution obtained by dissolving potassium permanganate or sodium permanganate in an aqueous solution of potassium hydroxide or sodium hydroxide can be used.

The washing using the above alkaline permanganate solution can be exemplified by: a method of immersing the printed wiring board obtained by the above method in an alkaline permanganate solution set at 20 to 60 ℃; and a method of spraying an alkaline permanganate solution onto the printed wiring board by using a sprayer or the like. The printed wiring board may be subjected to a treatment of bringing the printed wiring board into contact with a water-soluble organic solvent having an alcoholic hydroxyl group before cleaning, for the purpose of improving wettability of the substrate surface with an alkaline permanganate solution and improving cleaning efficiency. Examples of the organic solvent include methanol, ethanol, n-propanol, and isopropanol. One kind of these organic solvents may be used, or two or more kinds may be used in combination.

The concentration of the alkaline permanganate solution may be appropriately selected as required, and preferably 0.1 to 10 parts by mass of potassium permanganate or sodium permanganate is dissolved in 100 parts by mass of 0.1 to 10% by mass of potassium hydroxide or sodium hydroxide aqueous solution, and more preferably 1 to 6 parts by mass of potassium permanganate or sodium permanganate is dissolved in 100 parts by mass of 1 to 6% by mass of potassium hydroxide or sodium hydroxide aqueous solution from the viewpoint of cleaning efficiency.

In the case of performing the above-mentioned cleaning using an alkaline permanganate solution, it is preferable that the printed wiring board which has been cleaned is treated with a liquid having a neutralizing and reducing action after the cleaning using the alkaline permanganate solution. Examples of the liquid having neutralizing and reducing actions include 0.5 to 15% by mass of dilute sulfuric acid or an aqueous solution containing an organic acid. Examples of the organic acid include formic acid, acetic acid, oxalic acid, citric acid, ascorbic acid, and methionine.

The cleaning with the alkaline permanganate solution may be performed after the cleaning performed to prevent the silver component dissolved in the etching solution from adhering to and remaining on the printed wiring board, or may be performed using only the alkaline permanganate solution instead of the cleaning performed to prevent the silver component dissolved in the etching solution from adhering to and remaining on the printed wiring board.

Further, the printed wiring board obtained using the laminate for a printed wiring board of the present invention can suitably perform, if necessary, lamination of a cover film on a circuit pattern, formation of a solder resist layer, nickel-gold plating, nickel-palladium-gold plating, palladium-gold plating as a final surface treatment of the circuit pattern.

The laminate for a semi-additive method of the present invention described above can produce a substrate with smooth surfaces and double-sided connection of circuit patterns, which has high adhesion to various smooth substrates, excellent design reproducibility, and a good rectangular cross-sectional shape, without using a vacuum apparatus. Therefore, by using the laminate for a semi-additive method of the present invention, a substrate for a printed wiring board and a printed wiring board having high density and high performance in various shapes and sizes can be provided at low cost, and the laminate has high industrial applicability in the field of printed wiring boards. Further, by using the laminate, not only a printed wiring board but also various members having a patterned metal layer on the surface of a planar substrate, for example, a connector, an electromagnetic wave shield, an antenna such as an RFID, a film capacitor, and the like can be manufactured.

Examples

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. In the following examples and comparative examples, "parts" and "%" are on a mass basis.

Production example 1: production of primer (B-1)

In a nitrogen-substituted container equipped with a thermometer, a nitrogen inlet pipe, and a stirrer, 100 parts by mass of a polyester polyol (a polyester polyol obtained by reacting 1, 4-cyclohexanedimethanol, neopentyl glycol, and adipic acid), 17.6 parts by mass of 2, 2-dimethylolpropionic acid, 21.7 parts by mass of 1, 4-cyclohexanedimethanol, and 106.2 parts by mass of dicyclohexylmethane-4, 4' -diisocyanate were reacted in a mixed solvent of 178 parts by mass of methyl ethyl ketone, thereby obtaining a urethane prepolymer solution having an isocyanate group at the end.

Next, 13.3 parts by mass of triethylamine was added to the urethane prepolymer solution to neutralize the carboxyl groups of the urethane prepolymer, and 380 parts by mass of water was further added thereto and sufficiently stirred, thereby obtaining an aqueous dispersion of the urethane prepolymer.

To the aqueous dispersion of the urethane prepolymer obtained above, 8.8 parts by mass of a 25% by mass aqueous ethylenediamine solution was added and stirred, whereby the urethane prepolymer was subjected to chain extension. Then, the resultant mixture was aged and desolventized to obtain an aqueous dispersion (nonvolatile component: 30 mass%) of the urethane resin. The weight average molecular weight of the urethane resin was 53,000.

Next, 140 parts by mass of deionized water and 100 parts by mass of the aqueous dispersion of the urethane resin obtained above were charged into a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen gas inlet pipe, a thermometer, a dropping funnel for dropping the monomer mixture, and a dropping funnel for dropping the polymerization catalyst, and the temperature was raised to 80 ℃ while blowing nitrogen gas. Then, while maintaining the temperature in the reaction vessel at 80℃with stirring, a monomer mixture composed of 60 parts by mass of methyl methacrylate, 30 parts by mass of N-butyl acrylate and 10 parts by mass of N-butoxymethacrylamide, and 20 parts by mass of a 0.5% ammonium persulfate aqueous solution were added dropwise from a separate dropping funnel over 120 minutes, respectively.

After the completion of the dropwise addition, the reaction vessel was cooled to 40 ℃ after further stirring at this temperature for 60 minutes, diluted with deionized water so that the nonvolatile content became 20 mass%, and then filtered with a 200-mesh filter cloth, whereby an aqueous dispersion of a core-shell type composite resin having the urethane resin as a shell layer and an acrylic resin having methyl methacrylate or the like as a core layer, that is, a resin composition for a primer layer, was obtained. Next, isopropyl alcohol and deionized water were added to the aqueous dispersion so that the mass ratio of isopropyl alcohol to water became 7/3 and the nonvolatile content became 2 mass%, and mixed to obtain a primer (B-1).

Production example 2: production of primer (B-2)

In a reaction flask equipped with a reflux condenser, a thermometer, and a stirrer, 200 parts by mass of water and 350 parts by mass of methanol were added to 600 parts by mass of formalin containing 37% by mass of formaldehyde and 7% by mass of methanol. Then, to the aqueous solution, 25 mass% aqueous sodium hydroxide solution was added, the pH was adjusted to 10, and then 310 parts by mass of melamine was added thereto, and the temperature of the solution was raised to 85℃to carry out a methylolation reaction for 1 hour.

Then, formic acid was added and after adjusting to pH7, it was cooled to 60 ℃ to carry out etherification reaction (secondary reaction). The etherification reaction was stopped by adding a 25 mass% aqueous sodium hydroxide solution at a cloudiness temperature of 40℃to adjust the pH to 9 (reaction time: 1 hour). Residual methanol was removed under reduced pressure at a temperature of 50 ℃ (methanol removal time: 4 hours) to obtain a resin composition for primer containing a melamine resin having a nonvolatile content of 80 mass%. Next, methyl ethyl ketone was added to the resin composition and diluted and mixed, whereby a primer (B-2) having a nonvolatile content of 2% by mass was obtained.

Production example 3: production of primer (B-3)

9.2 parts by mass of 2, 2-dimethylolpropionic acid, 57.4 parts by mass of polymethylene polyphenyl polyisocyanate (Milliconate MR-200 manufactured by Tosoh Co., ltd.) and 233 parts by mass of methyl ethyl ketone were added to a reaction vessel provided with a thermometer, a nitrogen inlet pipe, a stirrer and replaced with nitrogen, and reacted at 70℃for 6 hours to obtain an isocyanate compound. Then, 26.4 parts by mass of phenol was supplied as a blocking agent into the reaction vessel, and reacted at 70℃for 6 hours. Then, cooled to 40℃to obtain a blocked isocyanate solution.

Then, 7 parts by mass of triethylamine was added to the obtained blocked isocyanate solution at 40 ℃ to neutralize the carboxyl group of the blocked isocyanate, water was added thereto and the mixture was sufficiently stirred, and then methyl ethyl ketone was distilled off to obtain a resin composition for a primer layer containing blocked isocyanate and water, the nonvolatile component of which was 20% by mass. Next, methyl ethyl ketone was added to the resin composition and diluted and mixed, whereby a primer (B-3) having a nonvolatile content of 2% by mass was obtained.

Production example 4: production of primer (B-4)

35 parts by mass of a novolak resin (PHENOLITE TD-2131, manufactured by DIC Co., ltd., hydroxyl equivalent of 104 g/eq.), 64 parts by mass of an epoxy resin (EPICLON 850-S, manufactured by DIC Co., ltd.; bisphenol A type epoxy resin, epoxy equivalent of 188 g/eq.) and 1 part by mass of 2, 4-diamino-6-vinyl S-triazine (VT, manufactured by Sizhou chemical Co., ltd.) were mixed, and then diluted and mixed with methyl ethyl ketone so that the nonvolatile content became 2% by mass, thereby obtaining primer (B-4).

Production example 5: production of primer (B-5)

35 parts by mass of a novolak resin (PHENOLITE TD-2131, manufactured by DIC Co., ltd., hydroxyl equivalent of 104 g/eq.), 64 parts by mass of an epoxy resin (EPICLON 850-S, manufactured by DIC Co., ltd.; bisphenol A type epoxy resin, epoxy equivalent of 188 g/eq.) and 1 part by mass of a silane coupling agent having a triazine ring (VD-5, manufactured by Sikuku Chemicals Co., ltd.) were mixed, and then diluted and mixed with methyl ethyl ketone so that the nonvolatile content became 2% by mass, thereby obtaining a primer (B-5).

Production example 6: production of primer (B-6)

750 parts by mass of phenol, 75 parts by mass of melamine, 346 parts by mass of 41.5% formalin, and 1.5 parts by mass of triethylamine were charged into a flask equipped with a thermometer, a condenser, a fractionating column, and a stirrer, and the temperature was raised to 100℃while taking care of heat release. After 2 hours of reaction at 100℃under reflux, water was removed under normal pressure while heating to 180℃over 2 hours. Then, unreacted phenol was removed under reduced pressure to obtain an aminotriazine modified novolak resin. The hydroxyl equivalent is 120 g/equivalent.

The aminotriazine novolac resin obtained above was mixed with 35 parts by mass of an epoxy resin (EPICLON 850-S manufactured by DIC Co., ltd.; bisphenol A type epoxy resin, epoxy equivalent 188 g/equivalent), and then diluted and mixed with methyl ethyl ketone so that the nonvolatile content became 2% by mass, thereby obtaining a primer composition (B-6).

Production example 7: production of primer (B-7)

48 parts by mass of the aminotriazine novolac resin obtained in production example 6 and 52 parts by mass of an epoxy resin (EPICLON 850-S manufactured by DIC Co., ltd.; bisphenol A type epoxy resin, epoxy equivalent 188 g/equivalent) were mixed, and then diluted and mixed with methyl ethyl ketone so that the nonvolatile content became 2% by mass, thereby obtaining a primer composition (B-7).

Production example 8: production of primer (B-8)

A primer composition (B-8) having a nonvolatile content of 2% by mass was obtained in the same manner as in production example 7 except that the amounts of the aminotriazine novolac resin and the epoxy resin were changed from 48 parts by mass to 39 parts by mass and from 52 parts by mass to 61 parts by mass, respectively.

Production example 9: production of primer (B-9)

A primer composition (B-9) having a nonvolatile content of 2% by mass was obtained in the same manner as in production example 8 except that the amounts of the aminotriazine novolac resin and the epoxy resin were changed from 48 parts by mass to 31 parts by mass and from 52 parts by mass to 69 parts by mass, respectively.

Production example 10: production of primer (B-10)

To 52 parts by mass of the aminotriazine novolac resin obtained in production example 7 and an epoxy resin (EPICLON 850-S manufactured by DIC Co., ltd.; bisphenol A type epoxy resin, epoxy equivalent 188 g/equivalent) were further mixed 1 part by mass of trimellitic anhydride, and then diluted and mixed with methyl ethyl ketone so that the nonvolatile content becomes 2% by mass, whereby a primer (B-10) was obtained.

Production example 11: production of primer (B-11)

350 parts by mass of deionized water and 4 parts by mass of a surfactant (25% by mass of an active ingredient "Latemul E-118B" manufactured by Kabushiki Kaisha) were added to a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet pipe, a thermometer and a dropping funnel, and the temperature was raised to 70℃while blowing nitrogen.

A part (5 parts by mass) of a monomer pre-emulsion obtained by mixing a vinyl monomer mixture composed of 47.0 parts by mass of methyl methacrylate, 5.0 parts by mass of glycidyl methacrylate, 45.0 parts by mass of n-butyl acrylate, 3.0 parts by mass of methacrylic acid, 4 parts by mass of a surfactant (Aqualon KH-1025 manufactured by first Industrial pharmaceutical Co., ltd.: 25% by mass of an active ingredient) and 15 parts by mass of deionized water was added to a reaction vessel with stirring, followed by adding 0.1 parts by mass of potassium persulfate, and polymerizing for 60 minutes while maintaining the temperature in the reaction vessel at 70 ℃.

Next, while maintaining the temperature in the reaction vessel at 70 ℃, 30 parts by mass of the remaining monomer pre-emulsion (114 parts by mass) and the aqueous solution of potassium persulfate (active ingredient 1.0% by mass) were added dropwise over 180 minutes using different dropping funnels, respectively. After the completion of the dropwise addition, the mixture was stirred at this temperature for 60 minutes.

The resin composition for primer layer used in the present invention was obtained by cooling the temperature in the reaction vessel to 40 ℃, using deionized water so that the nonvolatile content became 10.0 mass%, and then filtering the solution with a 200-mesh filter cloth. Next, water was added to the resin composition and diluted and mixed, whereby a primer (B-11) having a nonvolatile content of 5% by mass was obtained.

[ preparation example 1: preparation of silver particle Dispersion

A dispersion containing silver particles and a dispersing agent was prepared by dispersing silver particles having an average particle diameter of 30nm in a mixed solvent of 45 parts by mass of ethylene glycol and 55 parts by mass of ion-exchanged water using a compound obtained by adding polyoxyethylene to polyethyleneimine as a dispersing agent. Next, ion-exchanged water, ethanol, and a surfactant were added to the obtained dispersion, thereby preparing a 5 mass% silver particle dispersion.

Preparation example 2: preparation of etching solution for silver ]

To 47.4 parts by mass of water, 2.6 parts by mass of acetic acid was added, and further, 50 parts by mass of 35% hydrogen peroxide was added to prepare an etching solution (1) for silver. The molar ratio of hydrogen peroxide to carboxylic acid (hydrogen peroxide/carboxylic acid) of the silver etching solution (1) was 13.6, and the content ratio of the mixture of hydrogen peroxide and carboxylic acid in the silver etching solution (1) was 22.4 mass%.

(production of laminate for semi-additive method)

Example 1

In a polyimide film (manufactured by Tou DuPont Co., ltd.) as an insulating base material"Kapton100EN-C"; 25 μm thick) was coated with a silver particle layer 0.5g/m after drying using a desktop mini coater (K Printing Proofer manufactured by RK Print Coat Instruments Co.) ² The silver particle dispersion obtained in preparation example 1 was coated. Subsequently, the mixture was dried at 160℃for 5 minutes using a hot air dryer. Further, the film was turned over in the same manner as described above, and the silver particle layer was made 0.5g/m ² The silver particle dispersion obtained in preparation example 1 was coated and dried at 160 ℃ for 5 minutes using a hot air dryer, thereby forming silver particle layers on both surfaces of the polyimide film. The film base material thus obtained was fired at 250℃for 5 minutes, and conduction of the silver particle layer was confirmed by a tester.

A polyester releasable adhesive tape (manufactured by Panac corporation, panaprotect HP/CT) having a thickness of 38 μm was laminated as a releasable cover layer (RC) on the polyimide film having conductive silver particle layers on both surfaces, and a laminate for a semi-additive method was produced in which a silver particle layer (M1) and a releasable cover layer (RC) were laminated in this order on both surfaces of a polyimide film as an insulating substrate (A).

Example 2

The dried silver particle layer is from 0.5g/m ² Changed to 0.8g/m ² Except for this, a laminate for a semi-additive method was produced in which a silver particle layer (M1) and a releasable coating layer (RC) were laminated in this order on both surfaces of a polyimide film as an insulating substrate (a) in the same manner as in example 1.

Example 3

The primer (B-1) obtained in production example 1 was applied to the surface of a polyimide film (Kapton 100EN-C, manufactured by Tou corporation, thickness 25 μm) using a desktop small coater (K Printing Proofer, manufactured by RK Print Coat Instruments Co.) so that the thickness after drying became 120nm, and then dried at 80℃for 5 minutes using a hot air dryer. Further, the primer (B-1) obtained in production example 1 was applied to the film by turning over the film in the same manner as described above so that the thickness after drying became 120nm, and dried at 80 ℃ for 5 minutes using a hot air dryer, whereby primer layers were formed on both surfaces of the polyimide film.

A laminate for a semi-additive method was produced in which the primer layer (B), the conductive silver particle layer (M1), and the releasable cover layer (RC) were laminated in this order on both surfaces of the polyimide film as the insulating substrate (a) in the same manner as in example 2, except that the insulating substrate (a) was changed from the polyimide film to the polyimide film obtained as described above, in which the primer layers were formed on both surfaces of the polyimide film.

(manufacture of printed Wiring Board)

Example 4

In the laminate for semi-additive method manufactured in example 1, the conductive silver particle layer (M1) and the releasable coating layer (RC) were laminated in this order on both surfaces of the polyimide film as the insulating substrate (a), through holes having a diameter of 100 μm were formed by using a drill at positions designed at connection positions with the rear solid GND in the transmission characteristic evaluation terminal of the microstrip line having a wiring length of 100mm and an impedance of 50Ω. The thus obtained substrate with through holes was subjected to a black hole process (whole hole-carbon adsorption treatment-etching) by MacDermid company, carbon was attached to the surface of the through holes, and after drying the film, the carbon-attached release coating layer (RC) was peeled off, whereby the conductive silver particle layer (M1) on the polyimide film was exposed. By inspecting the front and back surfaces of the silver particle layer on the film with a tester, it was confirmed that the front and back surfaces were electrically connected, ensuring conductivity.

On the silver particle layer (M1) thus obtained, a dry film resist (Photoc RD-1225 manufactured by Hitachi chemical Co., ltd.; resist film thickness 25 μm) was pressure-bonded at 100℃using a roll laminator, and then a microstrip line pattern having a wiring length of 100mm and an impedance of 50Ω and a terminal pad pattern for measuring a through hole portion of a probe connected to GND were exposed on the resist using a direct exposure digital imaging device (Nuvogo 1000R manufactured by Orbao technology Co.). Then, a microstrip line pattern and a pattern resist from which a probe terminal pad portion was removed were formed on the silver particle layer (M1) by developing with a 1 mass% aqueous sodium carbonate solution, and the silver particle layer (M1) on the polyimide film was exposed.

Then, the surface of the silver particle layer of the substrate on which the pattern resist was formed was set as a cathode, phosphorus-containing Copper was used as an anode, and a plating solution (60 g/L of Copper sulfate, 190g/L of sulfuric acid, 50mg/L of chloride ion, additive (coater stream ST-901 manufactured by rombin electronic materials Co., ltd.) containing Copper sulfate) was used to perform plating at a current density of 2A/dm2 for 41 minutes, whereby a circuit pattern layer (M2) 18 μm thick was formed by plating Copper on the microstrip pattern and probe terminal pad portion from which the resist was removed. Next, the film on which the copper metal pattern was formed was immersed in a 3 mass% aqueous sodium hydroxide solution set to 50 ℃.

Next, the film obtained above was immersed in the etching liquid for silver obtained in preparation example 2 at 25 ℃ for 30 seconds, thereby removing the silver particle layer other than the conductive layer pattern, and a printed wiring board was obtained. The circuit pattern layer (M2) is a smooth surface, and has a rectangular shape without undercut, without reducing the wiring height and wiring width, with respect to the cross-sectional shape of the circuit forming portion (microstrip line and probe terminal portion) of the printed wiring board to be manufactured.

Example 5

A printed wiring board having a microstrip line with a wiring length of 100mm, an impedance of 50Ω, and a copper thickness of 18 μm and a probe terminal portion pattern layer (M2) was produced in the same manner as in example 4 except that the laminate for the half-additive method used in example 4 was changed from the laminate produced in example 1 to the laminate produced in example 3. The printed wiring board circuit forming portion thus produced has a rectangular shape without undercut, without reduction in wiring height and wiring width, and is a circuit pattern layer (M2) with a smooth surface.

Example 6, 7

In examples 4 and 5, a printed wiring board having a microstrip line with a wiring length of 100mm, an impedance of 50Ω, a copper thickness of 18 μm, and a probe terminal portion pattern layer (M2) was produced in the same manner as in examples 4 and 5 except that a via hole with a diameter of 50 μm was formed using a laser instead of a drill. Regarding the cross-sectional shape of the printed wiring board circuit forming portion produced, there was no reduction in wiring height and wiring width in all cases, and a rectangular shape without undercut was exhibited, which was a circuit pattern layer (M2) with a smooth surface.

Examples 8 to 24

A printed wiring board having a microstrip line with a wiring length of 100mm, an impedance of 50Ω, a copper thickness of 18 μm, and a probe terminal portion pattern layer (M2) was produced in the same manner as in examples 1 to 7, except that the type of insulating base material, the type of primer used for the primer layer, the drying conditions thereof, the silver amount of the silver particle layer, and the via hole formation method were changed as shown in table 1 or 2. Regarding the cross-sectional shape of the printed wiring board circuit forming portion produced, there was no reduction in wiring height and wiring width in all cases, and a rectangular shape without undercut was exhibited, which was a circuit pattern layer (M2) with a smooth surface.

Example 25

In example 6, a substrate having a through-hole formed therein was immersed in a catalyst solution containing 1g/l of palladium chloride, 1ml/l of hydrochloric acid, and 1g/l of dimethylthiourea at 25℃for 3 minutes instead of performing the black hole process. Then, the substrate was washed with water, treated with a reducing solution containing 10g/l dimethylamine borane and 5g/l sodium hydroxide at 50℃for 2 minutes, and the surface of the via hole was electrically conductive with palladium. After this substrate was washed with water and then removed by etching treatment using the sulfuric acid/hydrogen peroxide aqueous solution prepared in preparation example 2, a printed wiring board having a microstrip line having a wiring length of 100mm, an impedance of 50Ω, a copper thickness of 18 μm and a conductive layer (M3) of a probe terminal portion pattern on the silver particle layer (M1) was prepared in the same manner as in example 6. The printed wiring board circuit forming portion thus produced has a smooth surface conductive layer (M3) which has a rectangular shape without undercut without decreasing the wiring height and wiring width.

Example 26

In example 6, a substrate having a through-hole formed therein was prepared in preparation example 4 (PPy/PVP (SO) ₄ ^2- ) Immersing in aqueous colloid solution at room temperature for 2 minutes to adhere colloid particles to the surface of the through-hole, and conducting electricity to the surface of the through-hole by using conductive polymer. After washing the substrate with water, passingAfter removal by etching treatment using the sulfuric acid/hydrogen peroxide aqueous solution prepared in preparation example 2, a printed wiring board having a microstrip line having a wiring length of 100mm, an impedance of 50Ω, a copper thickness of 18 μm and a conductive layer (M3) of a probe terminal portion pattern on the silver particle layer (M1) was prepared in the same manner as in example 6. The printed wiring board circuit forming portion thus produced has a smooth surface conductive layer (M3) which has a rectangular shape without undercut without decreasing the wiring height and wiring width.

Example 27

In example 1, a laminate for a semi-additive method was produced in the same manner as in example 1, except that the releasable coating layer (RC) was changed from a polyester releasable adhesive tape (panapect HP/CT manufactured by panapetec corporation) having a thickness of 38 μm to a dry film resist (Riston FXR20 manufactured by romend electronics corporation) having a thickness of 20 μm, and the conductive silver particle layer (M1) and the releasable coating layer (RC) were sequentially laminated on both surfaces of the polyimide film as the insulating substrate (a).

With respect to the laminate thus obtained, a through hole having a diameter of 100 μm was formed using a drill at a position designed at a connection position with the rear solid GND in the transmission characteristic evaluation terminal of the microstrip line having a wiring length of 100mm and an impedance of 50Ω. The thus obtained substrate with through holes was subjected to a black hole process (entire hole-carbon adsorption treatment-etching) by MacDermid company, carbon was attached to the surface of the through holes, and then immersed in a 5% aqueous sodium hydroxide solution set at 40 ℃ for 30 seconds, and the carbon-attached releasable cover layer (RC) was peeled off, whereby the conductive silver particle layer (M1) on the polyimide film was exposed. By inspecting the front and back surfaces of the silver particle layer on the film with a tester, it was confirmed that the front and back surfaces were electrically connected, ensuring conductivity.

On the silver particle layer (M1) thus obtained, a dry film resist (Riston FXR20, manufactured by rohdes electronics corporation) was pressure-bonded at 100 ℃ using a roll laminator, and then a microstrip line pattern having a wiring length of 100mm and an impedance of 50Ω and a terminal pad pattern for measuring a through hole portion of the probe connected to GND were exposed on the resist using a direct exposure digital imaging device (Nuvogo 1000R, manufactured by obu technologies). Then, a microstrip line pattern and a pattern resist from which a probe terminal pad portion was removed were formed on the silver particle layer (M1) by developing with a 1 mass% aqueous sodium carbonate solution, and the silver particle layer (M1) on the polyimide film was exposed.

Example 28

In example 3, a laminate for a semi-additive method was produced in the same manner as in example 3, except that the releasable coating layer (RC) was changed from a polyester releasable adhesive tape (panapect HP/CT manufactured by panapetec corporation) having a thickness of 38 μm to a dry film resist (Riston FXR20 manufactured by romend electronics corporation) having a thickness of 20 μm, and the primer layer (B), the conductive silver particle layer (M1), and the releasable coating layer (RC) were laminated in this order on both surfaces of the polyimide film as the insulating substrate (a).

With respect to the laminate thus obtained, a through hole of 100 μm diameter was formed using a drill at a position designed at a connection position with the rear solid GND in the transmission characteristic evaluation terminal of a microstrip line of 100mm in wiring length and 50 Ω in impedance, and then a printed wiring board was obtained in the same manner as in example 27. The cross-sectional shape of the circuit forming portion (microstrip line and probe terminal portion) of the printed wiring board thus manufactured was a smooth-surface circuit pattern layer (M2) having a rectangular shape without undercut without any reduction in the wiring height or wiring width.

Example 29

In example 6, a laminate for a semi-additive method was produced in which a primer layer (B), a conductive silver particle layer (M1), and a release coating layer (RC) were laminated in this order on both surfaces of a polyimide film as an insulating substrate (a) by changing the release coating layer (RC) from a polyester release adhesive tape (manufactured by Panac corporation, panoprotect HP/CT) to a dry film resist (manufactured by romeha electronics materials corporation, riston FXR 20) having a thickness of 20 μm.

The laminate thus obtained was subjected to formation of a through hole having a diameter of 100 μm using a drill at a position designed as a connection position with a solid GND on the back surface in a transmission characteristic evaluation terminal of a microstrip line having a wiring length of 100mm and an impedance of 50Ω, and then the through hole surface was electrically conductive with palladium in the same manner as in example 25, to produce a printed wiring board. The printed wiring board circuit forming portion thus produced has a smooth surface conductive layer (M3) which has a rectangular shape without undercut without decreasing the wiring height and wiring width.

Example 30

In example 29, the conductive layer was formed by conducting the conductive layer using the conductive polymer in the method of example 26 instead of conducting the conductive layer using palladium. The printed wiring board circuit forming portion thus produced has a smooth surface conductive layer (M3) which has a rectangular shape without undercut without decreasing the wiring height and wiring width.

Comparative example 1

Instead of using a polyimide film having silver particle layers formed on both sides, a commercially available 25 μm thick polyimide substrate FCCL (Upisel N-BE1310YSB manufactured by EXSYMO corporation) having roughened copper foil with a thickness of 3 μm on both sides as a plating base layer was used, and a through hole with a diameter of 100 μm was formed using a drill at a position designed to connect to a rear solid GND in a transmission characteristic evaluation terminal of a microstrip line with a wiring length of 100mm and an impedance of 50Ω in the same manner as in the above-described example. The thus obtained substrate with through holes was subjected to a black hole process (full hole-carbon adsorption treatment-etching) by MacDermid company, and the copper foil surface was etched according to a conventional method to remove carbon from the copper foil.

Next, a dry film resist (photo RD-1225 manufactured by hitachi chemical corporation; resist film thickness 25 μm) was pressure-bonded to the copper foil at 100 ℃ using a roll laminator, and then a microstrip line pattern having a wiring length of 100mm and an impedance of 50Ω and a terminal pad pattern for measuring a through hole portion connected to GND of a probe were exposed to the resist using a direct exposure digital imaging device (Nuvogo 1000R manufactured by obu technology corporation). Then, a microstrip line pattern and a pattern resist from which a probe terminal pad portion was removed were formed on the copper foil by developing with a 1 mass% aqueous sodium carbonate solution, and the silver particle layer (M1) on the polyimide film was exposed.

Then, the surface of the silver particle layer of the substrate on which the pattern resist was formed was set as a cathode, phosphorus-containing Copper was used as an anode, and a plating solution containing Copper sulfate (60 g/L of Copper sulfate, 190g/L of sulfuric acid, 50mg/L of chloride ion, additive (encoder stream ST-901 manufactured by rombin electronic materials corporation)) was used to perform plating at a current density of 2A/dm2 for 41 minutes, whereby a circuit pattern layer 18 μm thick was formed by plating Copper on the microstrip pattern and the probe terminal pad portion from which the resist was removed. Next, the film on which the copper metal pattern was formed was immersed in a 3 mass% aqueous sodium hydroxide solution set to 50 ℃.

Then, the conductive layer of the microstrip line is etched, the film thickness is reduced by about 3 μm, the wiring width is reduced by about 6 μm, and the cross-sectional shape cannot be maintained rectangular and becomes a "trapezoid" shape as a result of removing the copper seed crystal by immersing in a sulfuric acid-hydrogen peroxide flash etching liquid used for the copper seed crystal etching. Further, the surface of the copper conductive layer is roughened by etching, and the smoothness is lowered.

Comparative example 2

A polyimide film (Kapton 100EN-C manufactured by dolby eastern corporation; thickness 25 μm) obtained by sputtering nickel/chromium (thickness 30nm, nickel/chromium mass ratio=80/20) on both sides, further sputtering copper of 70nm, and performing a 1 μm thick electrolytic copper plating treatment was used as a plating base layer instead of the commercially available 25 μm thick polyimide base material FCCL (Upisel N-BE1310YSB manufactured by EXSYMO corporation) having a roughened copper foil of 3 μm on both sides, and a conductor circuit layer based on a copper microstrip line of 18 μm thickness and a probe terminal portion pad pattern was formed on the plating base layer of copper foil in the same manner as in comparative example 1.

Then, the copper seed crystal is removed by immersing the microstrip line in a sulfuric acid-hydrogen peroxide flash etching solution used for copper seed crystal etching, and as a result, the conductive layer (M3) of the microstrip line is etched, the film thickness is reduced by about 1 μm, the wiring width is reduced by 2 μm or more, and the cross-sectional shape cannot be maintained rectangular, and becomes a "trapezoid" shape. Further, the surface of the copper conductive layer is roughened by etching, and the smoothness is lowered. Further, only the copper layer is removed in the region other than the pattern of the conductive layer (M3), and the nickel/chromium layer remains without being removed.

[ confirmation of the existence of undercut and the sectional shape of the comb-shaped electrode portion ]

The cross section of the circuit pattern layer (M3) of the printed wiring board obtained as described above was enlarged 500 to 10,000 times by a scanning electron microscope ("JSM 7800" manufactured by japan electronics corporation) and observed to confirm the presence or absence of undercut and the cross-sectional shape of the circuit pattern layer (M3).

The surface roughness of the wiring surface of the printed wiring board thus produced was observed by a laser microscope (manufactured by kunsts corporation, VK-9710), and was evaluated as smooth (good) when Rz was 3 μm or less, and as not smooth (smoothness: ×) when Rz was more than 3 μm. In addition, when the difference between the design width of the wiring obtained from the resist for forming the wiring and the upper surface width of the wiring formed was 2 μm or less, it was evaluated that the undercut was suppressed, and the rectangular shape could be maintained (rectangularity: good), and when the difference was more than 2 μm, it was evaluated that the rectangular shape could not be maintained (rectangularity: ×), examples, comparative examples, and evaluation results are shown in tables 1 to 3.

TABLE 1

TABLE 2

TABLE 3

Symbol description

1: insulating base material

2: silver particle layer

3: releasable cover layer

4: primer layer

5: palladium, conductive polymer, carbon

6: through hole (through hole)

7: palladium, conductive polymers, or carbon

8: pattern resist

9: conductive layer (electrolytic copper plating layer)

(a) Laminate for semi-additive process

(b) Step 1: through hole (via hole) formation

(c) Step 2: through hole conduction

(d) And step 3: exposure of conductive silver particle layer

(e) And 4, step 4: pattern resist formation

(f) And step 5: conductive layer formation based on electroplated copper

(g) And step 6: pattern resist stripping

(h) And step 6: and removing silver seed crystals.

Claims

3. The laminate for a semi-additive method according to claim 1 or 2, wherein the silver particles constituting the silver particle layer (M) are coated with a polymer dispersant.

4. The laminate for semi-addition method according to claim 3, wherein the primer layer (B) is a layer made of a resin having a reactive functional group [ X ], and the polymer dispersant has a reactive functional group [ Y ], and the reactive functional group [ X ] and the reactive functional group [ Y ] can form a bond with each other by a reaction.

6. The laminate for a semi-additive process according to claim 5, wherein the polymer dispersant having the reactive functional group [ Y ] is 1 or more selected from the group consisting of polyalkyleneimines and polyalkyleneimines having a polyoxyalkylene structure containing an ethylene oxide unit.

8. A printed wiring board formed using the laminated body for a semi-additive method according to any one of claims 1 to 7.

9. A printed wiring board comprising a copper layer laminated on the silver particle layer (M1) of the laminated body for a semi-additive method according to any one of claims 1 to 7.

10. A method of manufacturing the printed wiring board according to claim 9, comprising:

step 1 of forming through holes penetrating both surfaces in a laminate in which a conductive silver particle layer (M) and a releasable coating layer (RC) are sequentially laminated on both surfaces of an insulating substrate (A);

11. A method of manufacturing the printed wiring board according to claim 9, comprising: