JP2003231991A - Pretreatment liquid for electrolytic plating, plating method, and method for manufacturing printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a direct plating process, which contributes to a cost reduction, controls global environmental problems and working environmental problems, and can directly electroplate copper without using an electroless plating process. <P>SOLUTION: The plating method comprises employing a colloidal liquid of an electroconductive polymer as a pretreatment liquid of electrolytic plating, depositing colloidal particles of the electroconductive polymer on a part of an insulating material to be conductor-plated, by contacting the liquid with the part, and then electroplating it. The method for manufacturing the printed wiring board is characterized by using the above plating method. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a plating method, a printed wiring board manufacturing method using the plating method, and
The present invention relates to a pretreatment liquid for electrolytic copper plating used in these methods.

[0002]

2. Description of the Related Art Conventionally, a method of plating through holes and via holes has been widely used to electrically connect an inner layer circuit of a printed wiring board. The plating is usually carried out by providing electroconductivity to the perforated hole wall by electroless copper plating and then electroplating.

However, the reducing agent formaldehyde used in the above electroless copper plating has become an environmental problem since the mid-1980s. It has been pointed out that this formaldehyde causes carcinogenicity to the human body and inflammation of the skin.

Further, the chelating agent in the electroless plating bath used for the electroless copper plating is also an environmental problem. For example, EDTA or the like is used as the chelating agent, but the presence of such a chelating agent makes it difficult to treat heavy metal ions in rivers. Especially in Europe, we are heading towards a ban on the use of EDTA.

Therefore, from the motive of protection of the global environment, improvement of working environment, etc., development of a so-called direct plating process in which electrolytic copper plating is directly performed on a substrate without using electroless copper plating has been developed since around 1983. Is coming. Currently there are about three direct processes, namely (1) Palladium-
The tin colloid process, (2) graphite process and (3) conductive polymer process are known.

The palladium-tin colloid process (1) is basically the same as the conventional catalysis of electroless copper plating, and there is no major difference except that the electroless copper process is replaced by electrolytic copper plating.

In the graphite process (2), the substrate is treated with a carbon black suspension, and the carbon is physically adsorbed (van der Waals force, polarity, electrostatic attraction) to adsorb carbon on the entire surface of the substrate. Then, direct electroplating is performed by utilizing the conductivity of this carbon.

In the conductive polymer process of (3) above, first, MnO ₂ necessary for oxidative polymerization of monomers is
The substrate is treated with permanganate to produce a solution of MnO ₂ by contacting it with an aqueous solution of a conductive polymer-forming monomer such as pyrrole in which a high boiling alcohol is dissolved.
Polymerization selectively proceeds on the surface of the substrate coated with to become a conductive polymer. Direct electrolytic plating is performed using this conductive polymer film.

However, all of these direct plating processes have the following drawbacks. That is, in the palladium-tin colloid process of (1) above,
The use of the expensive precious metal palladium is essential. In the above graphite process (2), since the carbon particle sizes are not uniform, there is a problem in product quality, particularly in the adhesion of the conductor to the substrate. In the conductive polymer process of the above (3), since permanganate containing a heavy metal is used as an oxidizing agent, wastewater treatment is complicated, and the conductive polymer-forming monomer used is unstable. Furthermore, since the monomer generates an odor, the working environment becomes poor.

[0010]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to contribute to cost reduction, suppress the problems in the global environment and the working environment, and to carry out the direct electrolytic copper plating without performing the electroless plating process. It is to provide a direct plating process capable of

[0011]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object. In the process, instead of generating a conductive polymer on the substrate surface, the idea was to attach a conductive polymer film obtained by previously polymerizing monomers under specific conditions to the substrate surface to impart conductivity. . However, since a conductive polymer is generally unnecessary for a solvent, it was extremely difficult to form a conductive polymer film.

However, in the subsequent research, it was found that when the monomer of the conductive polymer was chemically oxidatively polymerized under specific conditions, polymer particles having a particle diameter of about 100 nm were obtained, and thus an aqueous colloidal solution of the conductive polymer was obtained. Furthermore, when an aqueous colloidal solution of the conductive polymer is brought into contact with a portion of the insulating material to be plated, the colloidal particles of the conductive polymer adhere to the portion to form a conductive layer. It has been found that the electrolytic copper plating can be directly formed without applying the electroless plating to the place where the colloidal particles are attached.

The present invention has been completed after further studies based on these findings, and provides the following pretreatment liquid for electrolytic plating, a plating method and a method for manufacturing a printed wiring board.

Item 1 A pretreatment liquid for electrolytic plating comprising an aqueous colloidal liquid of a conductive polymer.

Item 2 is a plating method for conducting conductor plating on an insulating material, wherein the pretreatment liquid for electrolytic plating according to the above item 1 is brought into contact with a portion of the insulating material to be subjected to conductor plating, and a conductive polymer is added. A plating method, characterized in that colloidal particles are attached to the location, and then electrolytic plating is performed.

Item 3. A method for producing a printed wiring board having an insulating sheet for producing a printed wiring board and a conductor pattern formed on at least a part of the surface of the insulating sheet, wherein the conductor of the insulating sheet is formed. The step of bringing the pretreatment liquid for electroplating, which comprises the aqueous colloidal solution of the electroconductive polymer according to the above 1, into contact with the desired location to attach the electroconductive polymer colloid particles to the location, and attaching the electroconductive polymer colloid particles A method for manufacturing a printed wiring board, which includes a step of electrolytically plating copper on a damaged portion.

Item 4 The plating method according to Item 2, wherein the conductor plating of the insulating material is a hole inner surface of a via hole and / or a through hole formed in the insulating material for producing a printed wiring board and a land forming region. .

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Aqueous Colloidal Solution of Conductive Polymer The aqueous colloidal solution of conductive polymer used in the present invention is
It is an aqueous solution of conductive polymer particles to which a surfactant is attached. Such an aqueous colloidal solution is obtained by, for example, chemically oxidatively polymerizing a monomer capable of forming a conductive polymer in the presence of a dopant, an oxidizing agent and a surfactant to obtain a conductive polymer, isolating it, and redispersing it in water. It is obtained by

<Monomer> As the monomer for obtaining the conductive polymer used in the present invention, various monomers can be used, and among them, pyrrole and a pyrrole derivative, aniline and an aniline derivative can be exemplified. As the pyrrole and the pyrrole derivative, the general formula (1)

[0020]

[Chemical 1]

[In the formula, R ¹ , R ² and R ³ are the same or different and each represents a hydrogen atom or a monovalent organic group. ] The compound represented by these can be mentioned. These compounds may be used alone or in combination of two or more kinds.

The aniline and aniline derivative are represented by the general formula (2)

[0023]

[Chemical 2]

[Wherein R ⁹ , R ¹⁰ , R ¹¹ , R ¹² and R
¹³ is the same or different and represents a hydrogen atom or a monovalent organic group. ] The compound represented by these can be mentioned. These aniline compounds may be used alone or in combination of two or more.

In the above general formulas (1) and (2), examples of the monovalent organic group include an alkyl group having 1 to 5 carbon atoms such as a methyl group and an ethyl group, a methoxy group and an ethoxy group. An aryl group having 6 to 9 carbon atoms such as an alkoxy group having 1 to 6 carbon atoms, a phenyl group and a tolyl group (especially mono (C1-
C3 alkyl) phenyl group), benzyl group, phenethyl group and the like, aralkyl group having 7 to 10 carbon atoms (especially phenyl group).
C1-C4 alkyl group) and the like. These carbon numbers 1 to
The alkyl group having 5 to 6 carbon atoms, the alkoxy group having 1 to 6 carbon atoms, the aryl group having 6 to 9 carbon atoms, and the aralkyl group having 7 to 10 carbon atoms may have one substituent such as a hydroxyl group.

The compounds represented by the above general formulas (1) and (2) are either known or can be easily produced according to known methods.

Pyrrole derivative represented by the above general formula (1)
In the body, pyrrole, N- (C₁-C₃Alkyl) pyro
, Especially N-methylpyrrole, C at the 3- and / or 4-position
₁-C ₃Pyrrole having an alkyl group, for example 3-methyl
Lupyrrole, 4-methylpyrrole, 3,4-dimethylpyrrole
Rolls and the like are preferred. In addition, the formula represented by the general formula (2)
Among the niline compounds, aniline and o-methylaniline
And m-methylaniline are preferred. <Dopant> As the dopant, sulfuric acid, perchloric acid,
An inorganic acid such as nitric acid can be exemplified. These inorganic acids have acid groups
At least some of the sodium, potassium and ammonium salts
It may be in the form of a salt such as um salt. In such salt form
Sodium sulfate, sodium nitrate as dopant
Etc. can be illustrated.

The amount of these dopants used is 1 to 20 mol of the free acid group per 1 mol of the compound represented by the general formula (1) or the compound represented by the general formula (2) as the above monomer. , And more preferably 5 to 15 mol.

<Oxidizing Agent> The oxidizing agent may be any one that can chemically oxidatively polymerize the compound represented by the general formula (1) or the aniline compound represented by the general formula (2) as the monomer. However, for example, persulfates such as ammonium persulfate and sodium persulfate, hydrogen peroxide-ferrous iron salt and the like are preferably used. These oxidizing agents may be used alone or in combination of two or more kinds.

It is also possible to use permanganates such as potassium dichromate and potassium permanganate and dichromates such as potassium dichromate as the above-mentioned oxidizing agent, but these are used as wastewater. Since it contains a heavy metal which causes problems in processing, it is preferable not to use it as much as possible. In the present invention, it is preferable to use the above-mentioned persulfate as an oxidizing agent.

The amount of the above-mentioned oxidizing agent can be selected from a wide range, but in general, it is 0.1 to 10 per 1 mol of the above-mentioned monomer.
It is used in an amount of 1 mol, particularly preferably 1 to 5 mol.

<Surfactant> Examples of the surfactant include polyvinylpyrrolidone and polyvinyl alcohol. Among these, polyvinylpyrrolidone having a molecular weight of about 40,000 to 360,000 and polyvinyl alcohol having a degree of polymerization of about 500 to 2000 are preferable. These surfactants are preferably used in an amount of 0.1 to 20 g, particularly 5 to 15 g, relative to 1 mol of the above monomer.

<Polymerization Method> The above monomers can be polymerized by various methods. For example, the above-mentioned surfactant is dissolved in water, particularly warm water (temperature = 30 to 60 ° C, especially about 40 ° C), an oxidizer and a dopant are added, and a monomer is further added to the mixture at 8 to 20 ° C at 8 to 30 ° C. A method of reacting for about 24 hours, particularly about 12 hours can be adopted.

The conductive polymer particles are isolated by subjecting the obtained polymerization reaction mixture to a known separation operation such as centrifugation. When centrifugation is used as the separation means, for example, the conductive polymer fine particles are completely precipitated at about 16000 g for 30 to 60 minutes.

The conductive polymer particles thus obtained are
During the polymerization, a positive charge is generated in the polymer skeleton due to the oxidation of the oxidizing agent, and in order to compensate for this, an anion derived from the dopant is used.
^- is happening is doped. The amount of the doped anion is not particularly limited, but in the case of polypyrrole, for example, usually one dopant is often introduced to about three pyrrole rings.

The conductive polymer fine particles obtained are
The particle size is about 100 to 200 nm, especially about 150 nm.

Further, since a small amount of a surfactant is attached to the obtained conductive polymer fine particles, the conductive polymer particles obtained by the above method can be easily redispersed in water. An aqueous colloidal solution of the conductive polymer of the present invention can be obtained.

The concentration of the conductive polymer particles (including the doped anion and the adhering surfactant) in the aqueous colloidal solution is not particularly limited and can be appropriately selected from a wide range, but usually 0.1 to 15 g / It is preferably about L, particularly about 5 to 10 g / L.

Pretreatment Solution for Electrolytic Plating In the present invention, an aqueous colloidal solution of the above conductive polymer is added to
Used as a pretreatment solution for electrolytic plating.

The pretreatment liquid for electrolytic plating comprising the above aqueous colloidal liquid of the conductive polymer of the present invention has good liquid stability and requires the use of expensive noble metal as in the conventional palladium-tin colloidal process. Not.

Further, by pretreatment with the pretreatment liquid of the present invention, it is possible to directly perform electrolytic plating without performing electroless copper plating. Therefore, a chelating agent or formalin used in electroless plating, etc. There is no problem in the global environment or working environment.

By bringing the pretreatment liquid for electroplating, which is an aqueous colloidal solution of the above-mentioned conductive polymer of the present invention, into contact with the portion to be plated with the insulating material, the particles of the conductive polymer adhere to the portion. A conductive layer is formed. By forming the conductive layer in this manner, electrolytic plating can be performed without performing electroless copper plating.

Various methods can be adopted to bring the pretreatment liquid into contact with the portion to be subjected to electrolytic plating. For example, a method of immersing an insulating material in the pretreatment liquid of the present invention can be mentioned. The conditions for the immersion are not particularly limited as long as they can be selected from a wide range, but for example, it is preferable to set the temperature at 20 to 30 ° C. for about 1 to 5 minutes.

Plating Method The present invention also provides an electrolytic plating method using the pretreatment liquid for electrolytic plating of the present invention. In particular, the plating method of the present invention is a plating method for conducting conductor plating on an insulating material, and electrolytic plating consisting of an aqueous colloidal solution of the conductive polymer of the present invention is applied to a location on the insulating material where conductor plating is to be performed. It is characterized in that the pretreatment liquid for use is brought into contact with the colloidal particles of the conductive polymer to adhere to the location, and then electrolytic plating is performed.

Examples of the insulating material include materials made of glass-epoxy, polyimide, polypropylene, fluororesin, liquid crystal polymer and the like.

The pretreatment liquid of the present invention is brought into contact with a portion of the insulating material to be electroplated to form a conductive layer made of colloidal particles of a conductive polymer. The conductive layer can be formed by, for example, the dipping method as described above.
Usually, the concentration of the conductive polymer colloid (including doped anion and attached surfactant) is 0.1 to 15 g / L.
To a pretreatment liquid of about 5 to 10 g / L, for example, 20
By contacting at a temperature of ~ 30 ° C for about 1 to 5 minutes,
A conductive layer sufficient to apply electrolytic plating is formed. If necessary, the concentration of the pretreatment liquid, the contact time, etc. can be appropriately changed.

The conductive layer thus formed is washed with water and / or a sulfuric acid aqueous solution, if necessary. The washing with the sulfuric acid aqueous solution can be exemplified by a method of using a sulfuric acid aqueous solution having a concentration of about 3 to 10% by weight and immersing at a temperature of 20 to 30 ° C for about 30 seconds to 90 seconds.

Next, electrolytic plating is applied. For electrolytic plating, an acidic plating bath can be used. As such an acidic plating bath, an electrolytic copper sulfate plating bath is preferable, but not limited to this, an electrolytic nickel plating bath or the like can also be used. These electrolytic platings can be performed using a conventionally known electrolytic plating solution.

With the conventional electrolytic plating pretreatment liquid, it was difficult to directly perform electrolytic plating on the fluororesin without performing electroless plating. However, in the plating method of the present invention, since the colloidal particles of the conductive polymer adhere well to the surface of the fluororesin material, it is possible to directly perform electrolytic plating on the fluororesin material surface. is there.

Particularly, in the plating method of the present invention, a conductor such as copper plating is formed on an insulating material for a printed wiring board,
It is useful for forming a conductor such as copper plating on the hole inner surface of a via hole and / or a through hole formed in the insulating material, a land forming region, etc., and can be advantageously used for manufacturing a printed wiring board.

Manufacturing Method of Printed Wiring Board As described above, in the present invention, a plating method using a pretreatment liquid for electrolytic plating comprising an aqueous colloidal solution of the above conductive polymer is applied to a printed wiring board, for example, A single-sided printed wiring board, a double-sided printed wiring board, a multilayer printed wiring board, a flexible printed wiring board, a build-up type printed wiring board, etc. can be advantageously manufactured.

Although various methods can be adopted for producing a printed wiring board using the above-mentioned electrolytic plating pretreatment liquid of the present invention, the so-called subtractive method is preferably adopted.

The present invention manufactures an insulating sheet for producing a printed wiring board and a printed wiring board having a conductor pattern formed on at least a part of the surface of the insulating sheet, without using electroless plating. A method, in which the conductor of the insulating sheet is to be formed, a step of contacting a pretreatment liquid for electroplating comprising an aqueous colloidal solution of the conductive polymer to attach the conductive polymer colloidal particles to the location, It is intended to provide a method for producing a printed wiring board, which includes a step of performing electrolytic copper plating on a place where the conductive polymer colloid particles are attached.

Examples of the insulating sheet for producing a printed wiring board include sheets made of glass-epoxy laminate, polyimide, polypropylene, fluororesin, liquid crystal polymer and the like. In addition, these sheets may be sheets having a copper layer such as a copper-clad laminated plate in which copper foil is laminated on one side or both sides, or may be a multilayer substrate, a flexible substrate or the like.

Using such an insulating material, the pretreatment liquid of the present invention is brought into contact with the place to be subjected to electrolytic plating to form a conductive layer composed of colloidal particles of a conductive polymer. This can be performed, for example, by the dipping method or the like as described in the section "Plating method".

In the method for producing a printed wiring board of the present invention, an insulating sheet for producing a printed wiring board such as a double-sided material or a multi-layered material in which a conductive layer such as a copper foil is previously formed on the front surface and the back surface is used. It is also possible to use an insulating sheet for producing a printed wiring board such as a double-sided material having no conductive layers such as copper foil on the front surface and the back surface, or a multilayer material.

Particularly, in the present invention, in a method for producing a printed wiring board by electrolytically plating an insulating substrate without performing electroless plating, electrolytic plating is performed as a pretreatment step for electrolytic plating treatment of the insulating substrate. The present invention provides a method for producing a printed wiring board, which comprises a step of treating an appropriate place with a pretreatment liquid for electrolytic plating comprising the aqueous colloidal liquid of the conductive polymer of the present invention.

<Embodiment 1> The present invention will be described below with reference to FIG. 1 showing an embodiment in which an insulating sheet for producing a printed wiring board having conductive layers on the front and back surfaces is used. In FIG. 1, an insulating sheet 1 made of an insulating material 2 is provided with inner layer copper foils 3 and 3 ′, and a multilayer material having conductive layers 9 and 9 ′ such as copper foil on the front and back surfaces is used. However, the present invention is also applicable to the case where a double-sided material or another material is used.

According to the first embodiment, (1a) a step of forming a via hole and / or a through hole in an insulating sheet for producing a printed wiring board having a conductive layer such as a copper foil, (1b) the above step (1a) The insulating sheet having the via holes and / or through holes obtained in 1. and the pretreatment liquid consisting of the aqueous colloidal solution of the conductive polymer of the present invention are contacted to coat the conductive polymer colloidal particle coating of the present invention with the inner surface of the hole. And a step of forming the entire surface of the conductive layer such as the copper foil, (1c)
A step of forming a conductive layer such as a copper plating layer by electrolytic plating on the entire surface of the conductive polymer colloidal particle coating, (1
d) a step of forming a pattern using an etching resist on the conductive layer formed by the electroplating method in the step (1c), (1e) forming the pattern by an electroplating method other than the circuit portion protected by the etching resist Conductive layer, the step of forming a circuit by etching and removing the conductive layer such as the conductive polymer colloidal particle coating and the conductive layer such as copper foil that was originally formed on the insulating sheet, and (1f) the formed circuit Provided is a method for manufacturing a printed circuit board which does not use electroless plating, which comprises a step of removing an etching resist from above.

More specifically, for example, first, FIG. 1 (a)
As shown in FIG. 6, via holes and / or drilling are performed on the insulating sheet 1 on which the conductive layers 9 and 9 ′ such as copper foil layers are formed to form via holes and / or through holes.

Next, the surface of the insulating sheet 1 and the inside of the holes are washed, and the copper foil surface is soft-etched, and as shown in FIG. The conductive polymer colloidal particle coating 4 of the present invention is contacted to form the inner surface of the hole and the entire surface of the copper foil. The aqueous colloidal solution of the conductive polymer of the present invention adheres to both the insulating material and the copper foil. In general,
From the result of SEM photograph, compared with the adsorption amount to the insulating material,
Little adsorption to the copper foil surface. The cleaning and soft etching can be performed by a conventionally known method.

Then, as shown in FIG. 1 (c), a conductive layer 5 such as a copper plating layer on the entire surface is formed on the conductive polymer colloid particle coating film 4 by electrolytic plating, and as shown in FIG. 1 (d). Then, a pattern is formed using an etching resist 6 such as a dry film, and as shown in FIG. 1 (e), the conductive layer 5 other than the portion protected by the etching resist, the conductive polymer colloid particle coating 4 of the present invention, and The copper foil 9, 9'which was originally formed was removed by etching with an etching solution such as sodium persulfate to form a circuit, as shown in FIG. 1 (f).
The etching resist is removed as shown in FIG.

As the etching resist 6 and the etching solution, those known in this field can be used. As the electrolytic plating for forming the conductive layer 5, copper sulfate electrolytic plating is preferable. The copper sulfate electrolytic plating can be performed using a conventionally known electrolytic copper plating solution used for manufacturing a printed wiring board. Moreover, you may wash with water between each process.

<Embodiment 2> The present invention will be described with reference to FIG. 2 showing another embodiment in which an insulating sheet for producing a printed wiring board in which a conductive layer is formed in advance is used. FIG. 2 shows a multi-layer material having inner layer copper foils 23 and 23 ′ in an insulating sheet 21 made of the insulating material 22,
The same applies when using a double-sided material or another material.

According to the second embodiment, (2a) a step of forming a via hole and / or a through hole in an insulating sheet for producing a printed wiring board having a conductive layer such as a copper foil, (2b) the above step (1a) ) Contacting the insulating sheet on which the via hole and / or the through hole is formed, and a pretreatment liquid consisting of the aqueous colloidal liquid of the conductive polymer of the present invention,
A step of forming a conductive polymer colloidal particle coating film of the present invention on the entire inner surface of the hole and the conductive layer surface such as the copper foil,
(2c) on the conductive polymer colloidal particle coating, a step of forming a pattern using a plating resist, (2d) on the conductive polymer colloidal particle coating not covered by the plating resist, copper plating A step of forming a conductive layer such as by electroplating, (2e) a step of forming an etching resist on the conductive layer formed by the electroplating in step (2d), (2f) the step (2e) From the obtained substrate, the step of peeling the plating resist, (2g) the above step
Except for the location protected by the etching resist coating formed in (2e), the step of etching the conductive polymer colloidal particle coating and the conductive layer such as the copper foil formed from the beginning, (2h) if necessary. Thus, there is provided a method of manufacturing a printed circuit board which does not use electroless plating, which comprises a step of removing the etching resist film.

More specifically, as shown in FIG. 2 (a), first, as shown in FIG. 2 (a), the insulating sheet 21 on which the conductive layers 29, 29 'such as copper foil layers are formed is subjected to via hole processing and / or drill processing. To form via holes and / or through holes.

Next, the surface of the insulating sheet 21 and the inside of the holes are cleaned, and the copper foil surface is soft-etched, and as shown in FIG. 2 (b), the conductive polymer of the present invention is brought into contact with an aqueous colloidal solution to form The conductive polymer colloidal particle coating 24 of the invention is formed on the entire inner surface of the hole and the surface of the copper foil.

Next, as shown in FIG. 2 (c), a pattern is formed on the conductive polymer colloidal particle coating 24 by using plating resists 26 and 26 'such as dry films. Next, as shown in FIG. 2 (d), a conductive layer 25 such as copper plating for a conductive circuit is formed on the portion not covered with the plating resists 26, 26 'by electrolytic plating, and then, as shown in FIG. 2 (e). As shown, an etching resist film 28 is formed on the conductive layer 25. Next, as shown in FIG. 2 (f), the plating resist 26 is peeled off with a release agent, and as shown in FIG. 2 (g), the conductive polymer colloidal particle film other than the part protected by the etching resist film 28 is removed. 24 and the conductive layers 29, 2 such as the copper foil formed from the beginning
9'is etched and removed with an etching solution such as sodium persulfate to form a circuit. If necessary, the etching resist film 28 is removed.

The plating resists 26, 26 ', the plating bath for forming the conductive layer 25 (especially electrolytic copper plating bath), the etching resist for forming the etching resist film 28, and the peeling for peeling the plating resist 26 As the agent, the etching solution and the like, those known in this field can be used. Moreover, you may wash with water between each process.

<Embodiment 3> Next, the present invention will be described with reference to FIG. 3 showing an embodiment in which an insulating sheet for producing a printed wiring board having no conductive layers on the front and back surfaces is used.
In FIG. 3, a multilayer material including inner layer copper foils 33 and 33 ′ in an insulating sheet 31 made of an insulating material 32 is used, but the present invention is also applicable to the case where a double-sided material or another material is used. Applicable to

According to the third embodiment of the present invention, first, referring to FIG.
As shown in (a), the insulating sheet 31 is subjected to via hole processing and / or drill processing to form via holes and / or through holes.

Next, the surface of the insulating sheet 31 and the inside of the holes are washed and, as shown in FIG. 3 (b), contacted with the pretreatment liquid consisting of the aqueous colloidal liquid of the conductive polymer of the present invention, and the present invention. The conductive polymer colloidal particle coating 34 is formed on the entire inner surface of the hole and the surface of the insulating sheet. The washing can be performed by a conventionally known method.

Next, as shown in FIG. 3 (c), a conductive layer 35 such as copper plating on the entire surface is applied on the conductive polymer colloidal particle coating 34 by electrolytic plating, and as shown in FIG. 3 (d). , Etching resist 36 such as dry film,
36 'is used to form a pattern, and as shown in FIG. 3 (e), a conductive layer 35 such as a copper plating layer and a conductive polymer colloidal particle coating 34 of the present invention are coated on a portion other than the portion protected by the etching resist. It is etched and removed with an etching solution such as sodium sulfate, and the etching resist is removed to form a circuit as shown in FIG. 3 (f).

As the etching resist 36, the plating bath for forming the conductive layer 35 such as the copper plating layer, and the etching solution, those known in the art can be used. Moreover, you may wash with water between each process.

<Embodiment 4> Further, the present invention will be described with reference to FIG. 4 showing another embodiment in which an insulating sheet for producing a printed wiring board having no conductive layers such as copper foil on the front surface and the back surface is used. explain. FIG. 4 shows a multi-layer material in which the inner layer copper foils 43 and 43 ′ are provided in the insulating sheet 41 made of the insulating material 42, but the same can be applied to the case where a double-sided material or another material is used.

According to the fourth embodiment of the present invention, first, referring to FIG.
As shown in (a), the insulating sheet 41 is subjected to via hole processing and / or drill processing to form via holes and / or through holes.

Next, the surface of the insulating sheet 41 and the inside of the holes are washed and brought into contact with the aqueous colloidal solution of the conductive polymer of the present invention, and as shown in FIG. 4 (b), the conductive polymer colloid of the present invention is obtained. The particle coating 44 is formed.

Next, as shown in FIG. 4 (c), a pattern is formed on the conductive polymer colloidal particle coating 44 by using plating resists 46 and 46 'such as a dry film. Next, as shown in FIG. 4 (d), a conductive layer 45 such as copper plating for a conductive circuit is formed only on necessary portions by electrolytic plating, and as shown in FIG. 4 (e), the conductive layer 45 is formed on the conductive layer 45. Then, an etching resist film 48 is formed. Then, FIG.
As shown in (f), the plating resists 46 and 46 'are peeled off with a release agent, and as shown in FIG. 4 (g), the conductive polymer colloidal particle coating 44 other than the portion protected by the etching resist coating 48 is removed. Is removed by etching with an etching solution such as sodium persulfate to form a circuit. If necessary, the etching resist film 48 is removed.

The plating resists 46 and 46 ', the plating bath for forming the conductive layer 45, the etching resist for forming the etching resist film 48, the release agent for removing the plating resists 46 and 46', and the etching solution. Any of those known in the art can be used. Moreover, you may wash with water between each process.

According to the first to fourth embodiments, after forming a circuit, various known techniques in the field of printed wiring boards can be appropriately applied.

Further, in Embodiments 1 to 4 described above, as described in the plating method of the present invention, after forming the conductive polymer colloid particle coating film of the present invention of the present invention, the polymer colloid is optionally used. The particle coating may be washed with a sulfuric acid aqueous solution. The washing with the sulfuric acid aqueous solution uses a sulfuric acid aqueous solution having a concentration of about 3 to 10% by weight, for example, a temperature
A method of immersing at 0 to 30 ° C. for about 30 to 90 seconds can be exemplified.

[0082]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples.
Various changes can be made without departing from the invention.

Example 1 Sulfate ion-doped polypyrrole / polyvinylpyrrolidone (PPy / PVP (SO ₄ ² )) colloid was synthesized by the following method.

That is, as described below, sodium sulfate was used as a dopant, ammonium persulfate was used as an oxidizing agent, and polyvinylpyrrolidone was used as a surfactant. Pyrrole was used as the monomer.

0.85 g of PVP (polyvinylpyrrolidone, manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 500 ml of warm water having a temperature of 40 ° C., and the solution thus obtained was ammonium persulfate as an oxidizing agent.
7.0g (0.03M), 32.2g sodium sulfate as a dopant
(0.2 M) was added, and water was further added to obtain a total amount of 1 L of an aqueous solution. 5 ml of pyrrole (Tokyo Kasei Co., Ltd., special grade) was added to the obtained aqueous solution, and the mixture was stirred at room temperature for about 12 hours to carry out chemical oxidative polymerization to obtain a polymerization reaction mixture. 16000g of this
A black deposit was obtained by centrifugation for 1 hour. The obtained deposit was washed several times with water and redispersed in 50 ml of water to give a colloidal solution. The concentration of the prepared PPy / PVP (SO ₄ ²⁻ ) aqueous colloidal solution was 10 g / L.

PPy / PVP (SO _{4 in the} obtained aqueous colloidal solution)
^2- ) The particle size of the colloidal particles was measured by an electron microscope, and the average particle size was about 150 nm.

A small amount of polyvinylpyrrolidone, which is a surfactant, was attached to the particles. The electric conductivity of the particles was 1 to 10 Scm. The conductivity was measured by immersing the comb-shaped electrode in a colloidal solution and drying it, and then measuring the resistance.

Example 2 A polyimide film having a thickness of 25 μm and a thickness of 9 μm on both sides
Using a double-sided copper foil polyimide substrate (manufactured by Ube Industries, Ltd.) having the copper foil of No. 3, a via hole having a diameter of 50 μm was processed by a UV laser.

The substrate thus processed was desmeared, further subjected to a cleaner conditioner step at 45 ° C. for 3 minutes, and further treated with a soft etching solution such as sodium persulfate.

Then, the PPy / PVP prepared in Example 1 was used.
It was dipped in an aqueous colloidal solution of (SO ₄ ²⁻ ) for 2 minutes at room temperature to adhere the colloidal particles to the via hole surface, and then the substrate was washed with water and directly subjected to copper sulfate electrolytic copper plating. Thus
An electrolytic copper plating layer having a thickness of 15 μm was applied to the copper foil surface and the via hole surface. Thus, the conductive polymer PP of the present invention
FIG. 6 shows an optical micrograph of a cross section of a via hole obtained by a direct plating method using an aqueous colloidal solution of y / PVP (SO ₄ ²⁻ ).

For comparison, a well-known direct plating method (Conductron DP manufactured by Meltex Co., Ltd.)
An optical micrograph of a cross section of a via hole formed by the process) is shown in FIG. The Meltex C
The direct plating method of o.,) is a Pd-Sn colloidal direct plating process.

From FIG. 6, it is apparent that the electrolytic copper plating film is formed in the via hole by the adhesion of the conductive polymer colloid of the present invention to the polyimide surface. Further, the electrolytic copper plating film obtained according to the present invention is 100
It also had good continuity after the cycle thermal shock test (according to the printed wiring board test method of JIS C 5012).

Example 3 Through holes were plated on the via holes of a build-up multilayer substrate in which fluororesin was laminated as a build-up layer on the front and back of a copper-clad glass-epoxy resin core substrate using a conductive polymer colloid.

First, a via hole having a diameter of 100 μm was formed in the build-up layer of the substrate by using a laser, the smear was removed and roughened on the surface of the fluororesin by desmearing, and a cleaner conditioner treatment step at 45 ° C. for 3 minutes Then, the copper surface was treated with a soft etching solution of sodium persulfate.

Then, the PPy / PVP prepared in Example 1 was prepared.
It was immersed in an aqueous solution of (SO ₄ ²⁻ ) for 2 minutes at room temperature to adhere colloidal particles onto the substrate. The substrate was washed with water, immersed in a 5% sulfuric acid aqueous solution for 1 minute, and then directly subjected to copper sulfate electroplating. A cross-sectional photograph of the obtained substrate is shown in FIG. In FIG. 7, F indicates a build-up layer made of fluororesin, and D
Is a conductor layer formed by forming a conductive polymer colloid particle layer on the build-up layer and on the inner surface of the via hole, and performing electrolytic copper plating on the layer, and E is a glass-
It is an epoxy resin core substrate, and C is a copper foil that is in close contact with the epoxy resin core substrate from the beginning.

When a printed wiring board is manufactured by using a normal electroless copper plating process, since electroless plating does not adhere to fluororesin, fluororesin material is used as long as the electroless plating method is adopted. It is extremely difficult to plate the inside of the via hole.

On the other hand, as is clear from FIG.
By adopting the manufacturing method of the present invention, it is clear that a fluororesin material can also be plated and a printed wiring board can be manufactured using an insulating material containing a fluororesin.

[0098]

The direct plating method using an aqueous colloidal solution of a conductive polymer of the present invention does not use a noble metal, so that the cost can be reduced.

Further, since the plating method of the present invention does not use electroless copper, there is no problem of environmental destruction due to complexing agents conventionally used in electroless copper plating baths and deterioration of working environment due to formaldehyde.

Further, the conventional plating method using a conductive polymer requires treatment with permanganate,
The plating method of the present invention does not require the use of permanganate, and has the advantage of shortening the plating process. Moreover, since the present invention does not directly use odorous monomers such as pyrrole, the environment at the plating site is improved.

Further, since the electroconductive polymer colloidal particles of the present invention are hydrophobic and have an electric charge, they can be directly electroplated on a resin having poor wettability with water, for example, a fluororesin. It is possible. Therefore, by adopting the method for producing a printed wiring board of the present invention, it is possible to produce a printed wiring board using a fluororesin, which has been extremely difficult to produce conventionally.

[Brief description of drawings]

FIG. 1 is a process drawing showing an example of a method for manufacturing a printed wiring board of the present invention.

FIG. 2 is a process drawing showing another example of the method for manufacturing a printed wiring board of the present invention.

FIG. 3 is a process drawing showing another example of the method for manufacturing a printed wiring board of the present invention.

FIG. 4 is a process drawing showing another example of the method for manufacturing a printed wiring board of the present invention.

FIG. 5 shows an optical microscope photograph of a cross section of a printed wiring board having via holes formed by a known direct plating method for comparison in Example 2.

FIG. 6 shows the conductive polymer PP of the present invention in Example 2.
1 is an optical micrograph of a cross section of a printed wiring board having via holes formed by a direct plating method using an aqueous colloidal solution of y / PVP (SO ₄ ²⁻ ).

FIG. 7 shows an optical micrograph of a cross section of a via hole obtained in Example 3.

[Explanation of symbols]

1 Insulation sheet 2 Insulation material 3,3 'inner layer copper foil 4 Conductive polymer colloid particle coating 5 Conductive layer 6 Etching resist 9,9 'conductive layer 21 Insulation sheet 22 Insulation material 23,23 'inner layer copper foil 24 Conductive polymer colloid particle coating 25 Conductive layer 26,26 'Plating resist 28 Etching resist 29, 29 'conductive layer 31 Insulation sheet 32 Insulation material 33,33 'inner layer copper foil 34 Conductive polymer colloidal particle coating 35 Conductive layer 36,36 'Etching resist 41 Insulation sheet 42 Insulation material 43,43 'inner layer copper foil 44 Conductive polymer colloidal particle coating 45 Conductive layer 46,46 'Plating resist 48 Etching resist C Copper foil adhered to epoxy resin core layer D conductor layer E Epoxy resin core layer F Fluororesin buildup layer

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4K024 AA03 AA09 AB01 BA12 BA15                       BB11 BC01 DA10 GA16                 5E343 AA07 AA18 AA33 BB24 BB67                       CC22 CC46 CC50 DD43 GG11                       GG20

Claims (3)

[Claims] 1. A pretreatment liquid for electrolytic plating comprising an aqueous colloidal liquid of a conductive polymer. 2. A plating method for conducting conductor plating on an insulating material, wherein the electroplating pretreatment liquid according to claim 1 is brought into contact with a portion of the insulating material where conductor plating is to be performed. A plating method, characterized in that colloidal particles are attached to the location, and then electrolytic plating is performed. 3. A method for producing a printed wiring board having an insulating sheet for producing a printed wiring board and a conductor pattern formed on at least a part of the surface of the insulating sheet, wherein the conductor of the insulating sheet is formed. A step of contacting the pretreatment liquid for electroplating, which comprises the aqueous colloidal solution of the conductive polymer according to claim 1, to attach the conductive polymer colloidal particles to the appropriate location, and depositing the conductive polymer colloidal particles A method for manufacturing a printed wiring board, which includes a step of electrolytically plating copper on a damaged portion.