JP2008211060A - Method of manufacturing substrate having metal film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a substrate having a metal film that allows the formation of a highly precise metal wiring having excellent adhesion to a substrate or an interlayer insulating resin film. <P>SOLUTION: The method of manufacturing a substrate having a metal film comprises the steps of: (a) forming, on the surface of the substrate or an interlayer insulating resin film, a polymer layer that is composed of a polymer which has a functional group that interacts with a metal ion or metal salt, and which is directly and chemically combined with the substrate or interlayer insulating resin film; (b) adding a metal ion or metal salt to the polymer layer; (c) reducing the metal ion or metal salt added to the polymer layer using a reducing agent to generate a metal; (d) forming a plating film on the polymer layer using an electroless plating solution; and (f) performing a thermal process at a temperature from 100 to 200°C subsequent to the step (d) of forming the plating film. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a substrate with a metal film, and more particularly to a method for manufacturing a substrate having a metal film for wiring in a printed wiring board.

A metal film formed on a substrate is used in various electrical appliances by being etched into a pattern.
The metal film (metal substrate) formed on the substrate has been subjected to an uneven treatment on the surface of the substrate in order to provide adhesion between the substrate and the metal layer, thereby exhibiting adhesion due to the anchor effect. As a result, the substrate interface portion of the resulting metal film becomes uneven, and there is a problem that the high-frequency characteristics are deteriorated when used as electrical wiring. Further, when forming the metal substrate, there has been a problem that a complicated process of treating the substrate with a strong acid such as chromic acid is required in order to process the unevenness of the substrate.

  In order to solve this problem, a method has been proposed in which a radically polymerizable compound is grafted on the surface of the substrate to modify the surface, thereby minimizing the unevenness of the substrate and simplifying the substrate processing process. However, this method requires an expensive device (γ ray generator, electron beam generator), and the substrate used is graft polymerization. Therefore, there is a concern that the graft polymer is not generated to a practically sufficient level because the polymerization initiating group that is the starting point of the polymer is not introduced.

On the other hand, as a method to improve the connection strength (adhesion) between the substrate and the metal layer in the build-up multilayer wiring board, the substrate surface of the polyimide film containing inorganic filler is roughened by permanganic acid treatment and then electroless copper plating is performed. In that case, a method of performing an annealing treatment after electroless copper plating is disclosed (for example, see Patent Documents 2 and 3). However, even if the adhesion is further improved by performing the annealing treatment, it is difficult to secure the adhesion with a roughened surface when a fine wiring having a width of, for example, 10 μm is formed.
In addition, a method is disclosed in which a substrate is roughened with an oxidizing agent, electroless copper plating is performed on the roughened surface, and then an annealing treatment is performed (see, for example, Patent Document 4). However, even if the adhesion is further improved by performing the annealing treatment, it is difficult to secure the adhesion with a roughened surface when a fine wiring having a width of, for example, 10 μm is formed.
Further, the insulating resin layer made of a thermosetting polyphenylene ether resin obtained by heating the thermosetting polyphenylene ether resin is subjected to plasma treatment, and then a conductor layer is provided, and then heat treatment is performed, thereby conducting the conductive layer and the insulating resin layer. Has been disclosed (for example, see Patent Document 5). However, the adhesion is good in that the conductor layer is densified by the heat treatment, but the effect of the heat treatment does not reach the surface modified portion that combines the conductor layer and the thermosetting polyphenylene ether, For example, when forming a fine wiring having a width of 10 μm or the like, the plasma treatment still has insufficient adhesion, and it is difficult to form a fine wiring.
It is difficult.
JP 58-196238 A JP 2006-108174 A JP 2006-108175 A JP 2005-39247 A JP 2004-165519 A “Advanced Materials”, 2000, No. 20, p. 1481-1494

  The objective of this invention is providing the manufacturing method of the board | substrate with a metal film which enables the high-definition metal wiring excellent in adhesiveness with a board | substrate or an interlayer insulation resin film.

In view of the above circumstances, the present inventors have conducted extensive research and found that the above problems can be solved, thereby completing the present invention.
That is, the present invention is achieved by the following means.

<1> (a) On the surface of a substrate or an interlayer insulating resin film, a polymer layer made of a polymer having a functional group that interacts with a metal ion or a metal salt and chemically bonded directly to the substrate or the interlayer insulating resin film is formed. A step, (b) a step of imparting a metal ion or metal salt to the polymer layer, and (c) a step of generating a metal by reducing the metal ion or metal salt imparted to the polymer layer with a reducing agent, (D) After the step of forming a plating film using an electroless plating solution on the polymer layer and (f) the step of forming the (d) plating film, heat treatment is performed at a temperature of 100 ° C. or higher and 200 ° C. or lower. A process for producing a substrate with a metal film, comprising the steps of:

<2> The method according to <1>, further comprising (e) a step of forming a metal film by electroplating between the step (d) of forming the plating film and the step of (f) the heat treatment. A manufacturing method of a substrate with a metal film.

<3> The method for producing a substrate with a metal film according to <2>, wherein the metal film contains Cu.
<4> The above <1> to <3>, wherein the polymer layer is formed by applying a coating solution containing a graft polymer precursor and then graft-polymerizing the graft polymer precursor by applying energy. The manufacturing method of the board | substrate with a metal film of any one of these.

<5> The method for producing a substrate with a metal film according to <4>, wherein the energy is light.
<6> The metal film according to any one of <1> to <5>, wherein the substrate or the interlayer insulating resin film has an arithmetic average surface roughness Ra of 0.01 to 0.5 μm. Manufacturing method of attached substrate.

<7> The method for producing a substrate with a metal film according to any one of <1> to <6>, wherein the heat treatment temperature is 120 ° C. or higher and 200 ° C. or lower.
<8> The substrate or the interlayer insulating resin film is at least one selected from silicon, epoxy resin, polyimide resin, polyimide amide resin, liquid crystal polymer, polyether imito resin, polyether ether ketone resin, and aramid resin. The method for producing a substrate with a metal film according to any one of <1> to <7>, wherein:

<9> The metal ion adsorbed on the polymer layer is at least one selected from the group consisting of Ag, Pd, Cu, Ni, Al, Fe, Co, and Cr. <1> The manufacturing method of the board | substrate with a metal film of any one of <8>.

  The “substrate” in the present invention refers to a polymer that can be chemically bonded directly to the surface. For example, when the polymer is directly chemically bonded to the resin film, the resin film itself (for example, an interlayer insulating film) In the case where an intermediate layer such as a polymerization initiation layer is provided on the surface of a substrate such as a resin film and the polymer is directly chemically bonded to the surface, the entire substrate provided with the intermediate layer on the film substrate is indicated.

  Hereinafter, a functional group that interacts with a metal ion or a metal salt is appropriately referred to as an “interactive group”.

The metal film obtained by the present invention is preferably provided with a metal film on a substrate having a surface irregularity of 500 nm or less, and the adhesion between the substrate and the metal film is 0.2 kN / m or more.
Here, when a polymer layer is formed on a substrate having a surface irregularity of 500 nm or less, the surface irregularity of the polymer layer is also 500 nm or less. After reducing the polymer layer by applying metal ions to the polymer layer, electroless plating, electroplating, etc. are performed so that the plating metal enters the polymer layer (composite state) and the polymer layer. A metal plating film is formed on the layer. The roughness of the metal film thus formed and its substrate interface (the interface between the metal and the polymer layer (organic component)) is slightly in comparison with the roughness of the polymer layer surface as the plated metal enters the polymer layer. However, since the degree thereof is low, the unevenness at the interface between the metal film (inorganic component) and the polymer layer (organic component) can be suppressed to such an extent that the high frequency characteristics of the formed metal film are not deteriorated. For this reason, when using a metal film as electrical wiring, excellent high frequency characteristics can be obtained. The high-frequency characteristics are characteristics that reduce transmission loss during high-frequency power transmission, and are characteristics that particularly reduce conductor loss among transmission losses.

In order to examine the details of the polymer layer (organic component) existing between the metal film and the substrate, the polymer layer existing between the substrate and the metal is deposited by electroless plating and electroplating. A polymer layer having a thickness of 0.05 μm or more in the direction of the substrate from the interface between the substrate and the metal film, in which a region containing 25% by volume or more of fine particles made of the metal is dispersed and present. However, it is considered that a composite state useful for metal adhesion is formed.
Here, if the unevenness on the surface of the substrate is reduced, the roughness of the substrate interface portion of the metal film can be further suppressed, and the high frequency characteristics of the resulting metal are improved. Therefore, a substrate with an unevenness of the surface of 100 nm or less should be used. Is preferred.

Further, the substrate surface of the metal part obtained by the present invention is surface-modified by surface grafting so that the unevenness of the substrate interface is kept to a minimum, and the substrate interface of the metal part is directly bonded to the substrate. It is considered that the adhesion between the formed metal film and the substrate is high because of the hybrid state with the graft polymer.
In the present invention, Ra in JIS B0601 (revised in 2010120), that is, “absolute value amount by arithmetic average of peaks and valleys” is used as the arithmetic average surface roughness Ra.
When the metal obtained by applying the present invention is applied to a wiring portion in various electronic materials such as a wiring board, the formed metal, that is, the unevenness of the interface between the metal of the wiring portion and the organic material is present. The smaller the frequency, the less electrical loss (transmission loss) during high-frequency power transmission.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the board | substrate with a metal film which enables the high-definition metal wiring excellent in adhesiveness with a board | substrate or an interlayer insulation resin film can be provided.

Hereinafter, the present invention will be described in detail.
In the method for producing a substrate with a metal film of the present invention, (a) a functional group that interacts with a metal ion or a metal salt (hereinafter also simply referred to as “metal ion”) is formed on the surface of the substrate or the interlayer insulating resin film. A step of forming a polymer layer made of a polymer that is directly chemically bonded to the substrate or the interlayer insulating resin film, (b) a step of applying a metal ion or a metal salt to the polymer layer, and (c) a step of applying to the polymer layer Reducing the generated metal ions or metal salts with a reducing agent to form a metal, (d) forming a plating film using an electroless plating solution on the polymer layer, and (f) the (d) And a step of performing a heat treatment at a temperature of 100 ° C. to 200 ° C. after the step of forming the plating film.

[(A) Polymer layer forming step]
The step (a) has a functional group (interactive group) that interacts with metal ions on the surface of a substrate or an interlayer insulating resin film (hereinafter collectively referred to as “substrate”). A polymer layer comprising a chemically bonded polymer is formed.

The step (a) includes (a-1) a step of producing a substrate on which a polymerization initiator layer containing a polymerization initiator is formed, and (a-2) a substrate on which the polymerization initiator layer is formed. Further, it is preferable to provide a step of providing a polymer layer comprising a polymer having an interactive group and directly chemically bonded to the substrate.
Further, the step (a-2) is performed by bringing the polymer having the polymerizable group and the interactive group into contact with the substrate on which the polymerization initiating layer has been formed, and then applying energy to the entire substrate surface. It is preferable to be a step of directly chemically bonding the polymer.

(Surface graft)
Formation of the polymer layer on the substrate uses a general method called surface graft polymerization. Graft polymerization is a method of synthesizing a graft (grafting) polymer by providing an active species on a polymer compound chain, thereby further polymerizing another monomer that initiates polymerization. In particular, when a polymer compound that gives active species forms a solid surface, this is called surface graft polymerization.

Any known method described in the literature can be used as the surface graft polymerization method applied to the present invention. For example, New Polymer Experimental Science 10, edited by Polymer Society, 1994, published by Kyoritsu Shuppan Co., Ltd., p135 describes a photograft polymerization method and a plasma irradiation graft polymerization method as surface graft polymerization methods. In addition, the adsorption technique manual, NTS Co., Ltd., supervised by Takeuchi, 1999.2, p203, p695 describes radiation-induced graft polymerization methods such as γ rays and electron beams.
As a specific method of the photograft polymerization method, the methods described in JP-A-63-92658, JP-A-10-296895, and JP-A-11-119413 can be used.

In addition to these, means for producing a polymer layer in which the ends of the polymer compound chains are directly chemically bonded are trialkoxysilyl groups, isocyanate groups, amino groups, hydroxyl groups, carboxyls at the ends of the polymer compound chains. It can also be formed by providing a reactive functional group such as a group and a coupling reaction between this and a functional group present on the substrate surface.
From the viewpoint of producing more surface graft polymer, photograft polymerization is preferred.

[Substrate or interlayer insulating resin film]
In the substrate or interlayer insulating resin film in the present invention, the end of a polymer compound having an interactive group (functional group that interacts with a metal ion) is chemically bonded to the surface directly or via a trunk polymer compound. The substrate itself or the substrate constituting the interlayer insulating resin film may have such surface characteristics, and an intermediate layer is separately provided on the substrate, and the intermediate The layer may have such characteristics. The base material will be described later.
In the present invention, the substrate includes an interlayer insulating film unless otherwise specified, such as when individually described.

In addition, as a means for producing a surface in which the end of a polymer compound chain having an interactive group is chemically bonded via a trunk polymer compound, a functional group capable of coupling reaction with a functional group on a substrate surface is available. There is a method in which a polymer compound having a group and an interactive group is synthesized, and the surface is formed by a coupling reaction between the polymer compound and a functional group on the substrate surface.
As another method, when the substrate surface has the property of generating radical species, a polymer compound having a polymerizable group and an interactive group is synthesized, and this polymer compound is applied to the substrate interface, There is a method in which radical species are generated and a substrate surface and a polymer compound are polymerized to form the surface.

In the present invention, as described above, an active species is given to the substrate surface, and a graft polymer is generated from the active species. However, when the graft polymer is generated, a polymerization initiating layer containing a polymerization initiator is formed on the substrate. [Step (a-1)] is preferable from the viewpoint of efficiently generating active sites and generating more surface graft polymer.
The polymerization initiation layer is preferably formed as a layer containing a polymerizable compound and a polymerization initiator.
The polymerization initiating layer in the present invention can be formed by dissolving necessary components in a solvent that can be dissolved, provided on the substrate surface by a method such as coating, and hardening by heating or light irradiation.

(A) Polymerizable compound The polymerizable compound used in the polymerization initiation layer is not particularly limited as long as it has good adhesion to the substrate and produces a surface graft polymer by applying energy such as actinic ray irradiation. However, a polyfunctional monomer or the like may be used, but an embodiment using a hydrophobic polymer having a polymerizable group in the molecule is particularly preferable.
Specific examples of the hydrophobic polymer include diene homopolymers such as polybutadiene, polyisoprene, and polypentadiene, and allyl group-containing monomers such as allyl (meth) acrylate and 2-allyloxyethyl methacrylate. A homopolymer of
Furthermore, binary or multi-component copolymers such as styrene, (meth) acrylic acid ester, (meth) acrylonitrile and the like containing diene monomers such as butadiene, isoprene and pentadiene or allyl group-containing monomers as constituent units;
And linear polymers or three-dimensional polymers having a carbon-carbon double bond in the molecule such as unsaturated polyester, unsaturated polyepoxide, unsaturated polyamide, unsaturated polyacryl, and high-density polyethylene.
In this specification, when referring to both or one of “acrylic and methacrylic”, it may be expressed as “(meth) acrylic”.
The content of the polymerizable compound is preferably in the range of 0 to 100% by mass, particularly preferably in the range of 10 to 80% by mass in terms of solid content in the polymerizable start layer.

(B) Polymerization initiator The polymerization initiator layer contains a polymerization initiator for expressing polymerization initiation ability by applying energy. The polymerization initiator used here is a known thermal polymerization initiator, photopolymerization initiator, or the like that can exhibit polymerization initiating ability by predetermined energy, for example, irradiation with actinic rays, heating, irradiation with electron beam, etc. Can be selected and used as appropriate. Among these, use of photopolymerization is preferable from the viewpoint of production suitability, and therefore, it is preferable to use a photopolymerization initiator.
The photopolymerization initiator is not particularly limited as long as it is active with respect to irradiated actinic rays and can be surface-grafted, and examples thereof include radical polymerization initiators, anionic polymerization initiators, and cationic polymerization initiators. From the viewpoint of reactivity, a radical polymerization initiator is preferable.

Specific examples of such a photopolymerization initiator include p-tert-butyltrichloroacetophenone, 2,2′-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one. Acetophenones such as: benzophenone (4,4′-bisdimethylaminobenzophenone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, ketones; benzoin, benzoin methyl ether, benzoin isopropyl Examples thereof include benzoin ethers such as ether and benzoin isobutyl ether; benzyl ketals such as benzyl dimethyl ketal and hydroxycyclohexyl phenyl ketone, and the like.
The content of the polymerization initiator is preferably in the range of 0.1 to 70% by mass, particularly preferably in the range of 1 to 40% by mass in terms of solid content in the polymerization initiator layer.

The solvent used when applying the polymerizable compound and the polymerization initiator is not particularly limited as long as these components can be dissolved. From the viewpoint of easy drying and workability, a solvent having a boiling point that is not too high is preferable. Specifically, a solvent having a boiling point of about 40 ° C to 150 ° C may be selected.
Specifically, acetone, methyl ethyl ketone, cyclohexane, ethyl acetate, tetrahydrofuran, toluene, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, acetylacetone, cyclohexanone, methanol, Ethanol, 1-methoxy-2-propanol, 3-methoxypropanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, - such as methoxypropyl acetate.
These solvents can be used alone or in combination. The concentration of the solid content in the coating solution is suitably 2 to 50% by mass.

The coating amount when forming the polymerization initiating layer on the substrate is 0.1 in terms of the mass after drying, from the viewpoint of sufficient polymerization initiating ability and maintaining film properties to prevent film peeling. -20 g / m ² is preferable, and 1-15 g / m ² is more preferable.

In the present invention, when the polymerization initiation layer is formed, as described above, the composition for forming the polymerization initiation layer is disposed on the surface of the substrate by coating or the like, and the film is formed by removing the solvent. However, at this time, it is preferable that the film is hardened by heating and / or light irradiation. In particular, if the film is dried by heating and then preliminarily cured by light irradiation, the polymerizable compound is cured to some extent in advance. Therefore, it can be suppressed. Here, the reason why light irradiation is used for pre-curing is the same as described in the section of the photopolymerization initiator.
The heating temperature and time may be selected under conditions that allow the coating solvent to be sufficiently dried. However, from the viewpoint of production suitability, the temperature is 100 ° C. or less, the drying time is preferably within 30 minutes, and the drying temperature is 40 to 80 ° C. It is more preferable to select heating conditions within a drying time of 10 minutes.

  Light irradiation performed as desired after heat drying can use a light source used in a grafting reaction described later. In the subsequent grafting reaction, from the viewpoint of not inhibiting the formation of the bond between the active site of the polymerization initiation layer and the graft chain carried out by applying energy, the polymerizable compound present in the polymerization initiation layer is partially Even if radical polymerization is performed, it is preferable to irradiate with light to such an extent that radical polymerization does not occur completely. About light irradiation time, although it changes with the intensity | strength of a light source, generally it is preferable within 30 minutes. As a standard for such pre-curing, it can be mentioned that the film remaining rate after solvent cleaning is 10% or less and the initiator remaining rate after pre-curing is 1% or more.

(Base material)
Examples of the material of the substrate used for the substrate or interlayer insulating film in the present invention include silicon, glass, plastic (epoxy resin, polyimide resin, polyimide amide resin, liquid crystal polymer, polyether imito resin, polyether ether ketone resin, aramid Resin, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal), paper, metal (eg, aluminum, zinc, copper) Etc.), paper on which the resin is laminated, paper on which a metal as described above is laminated or vapor-deposited, or the plastic film.
The shape of the substrate used in the present invention is preferably a dimensionally stable plate.

Moreover, the metal film obtained by this invention can be applied to a semiconductor package, various electrical wiring boards, etc. by patterning by an etching. When using for such a use, it is preferable to use the insulating resin shown below as a base material.
Examples of the insulating resin include resins such as polyphenylene ether or modified polyphenylene ether, cyanate ester compounds, and epoxy compounds. A substrate formed of a thermosetting resin composition containing one or more of these resins is preferably used. Preferred combinations when two or more of these resins are combined to form a resin composition include polyphenylene ether or modified polyphenylene ether and cyanate ester compound, polyphenylene ether or modified polyphenylene ether and epoxy compound, polyphenylene ether or modified polyphenylene ether and cyanate. Examples include combinations of ester compounds and epoxy compounds.

Examples of other insulating resins include 1,2-bis (vinylphenylene) ethane resin, and modified resins of this and polyphenylene ether resins. Such resins are described in detail in, for example, Satoru Amaha et al., “Journal of Applied Polymer Science” Vol. 92, p1252-1258 (2004).
Furthermore, liquid crystal polymers that can be obtained as commercial products under the name of “Kexar” manufactured by Kuraray and fluororesins represented by polytetrafluoroethylene (PTFE) are also preferred.
Of these resins, fluororesin (PTFE) is most excellent in high frequency characteristics among polymer materials. However, since it is a thermoplastic resin having a low Tg, it has poor dimensional stability against heat, and its mechanical strength is inferior to that of a thermosetting resin material. There is also a problem that the formability and workability are poor. A thermoplastic resin such as polyphenylene ether (PPE) can also be used after being alloyed with a thermosetting resin. For example, it can be used as an alloyed resin of PPE and epoxy resin, triallyl isocyanate, or an alloyed resin of PPE resin introduced with a polymerizable functional group and other thermosetting resins.
Epoxy resins have insufficient dielectric properties as they are, but improvements have been made through the introduction of bulky skeletons. In this way, the introduction and modification of structures that make use of the properties of each resin to compensate for its drawbacks. The resin which performed etc. is used preferably.
For example, cyanate ester is a resin having the most excellent dielectric properties among thermosetting, but is rarely used alone, and is used as a modified resin such as an epoxy resin, a maleimide resin, and a thermoplastic resin. Details of these are described in “Electronic Technology” 2002 No. 9, p35, and these descriptions can also be referred to in selecting such an insulating resin.

  When the metal film obtained by the present invention is applied to semiconductor packages, various electric wiring applications, etc., in order to suppress signal delay and attenuation from the viewpoint of processing large-capacity data at high speed, It is effective to lower the ratio and the dielectric loss tangent. The low dielectric loss tangent material is as described in detail in “Journal of Electronics Packaging” Vol. 7, No. 5, p397 (2004), and in particular, an insulating material having a low dielectric loss tangent characteristic should be adopted. Is preferable from the viewpoint of speeding up.

Specifically, the substrate used in such applications is a substrate made of an insulating resin having a dielectric constant (relative dielectric constant) at 1 GHz of 3.5 or less, or made of the insulating resin. A substrate having a layer on a substrate is preferred. Moreover, it is preferable that it is a board | substrate which consists of insulating resin whose dielectric loss tangent in 1 GHz is 0.01 or less, or a board | substrate which has the layer which consists of this insulating resin on a base material.
The dielectric constant and dielectric loss tangent of the insulating resin can be measured using a conventional method. For example, the cavity resonator perturbation method (for example, εr, tanδ measuring instrument for ultra-thin sheet, manufactured by Keycom Corporation) based on the method described in “18th Annual Conference of Electronics Packaging Society”, p189, 2004. ).
Thus, in the present invention, it is also useful to select an insulating resin material from the viewpoint of dielectric constant and dielectric loss tangent. Examples of the insulating resin having a dielectric constant of 3.5 or less and a dielectric loss tangent of 0.01 or less include a liquid crystal polymer, a polyimide resin, a fluororesin, a polyphenylene ether resin, a cyanate ester resin, and a bis (bisphenylene) ethane resin. In addition, these modified resins are also included.

The unevenness of the substrate and the substrate surface applied to the method for producing a substrate with a metal film of the present invention is preferably 500 nm or less, preferably 200 nm or less, more preferably 50 nm or less, and most preferably 20 nm or less.
The Rz (10-point average roughness) on the surface of the substrate and the substrate is 500 nm or less, preferably 100 nm or less, more preferably 50 nm or less, and most preferably 20 nm or less.
In addition, as a measuring method of Rz, it was measured according to JIS B0601 as “the difference between the average value of the Z data of the peak from the maximum to the fifth and the average value of the valley from the minimum to the fifth in the designated plane”. .

(Generation of graft polymer)
As described above, the graft polymer is generated in the step (a) by using a coupling reaction between the functional group present on the substrate surface and the reactive functional group of the polymer compound at the terminal or side chain. Alternatively, a method of directly photografting the substrate can be used.
In the present invention, a mode in which a polymer having a functional group (interactive group) that interacts with a metal ion and directly chemically bonded to the substrate is introduced onto the substrate on which the polymerization initiating layer is formed [(a- 2) Step] is preferable. More preferably, a polymer having a polymerizable group and an interactive group is brought into contact with the substrate on which the polymerization initiating layer has been formed, and then the polymer is directly chemically bonded to the entire substrate surface by applying energy. It is an aspect to make it. That is, a composition containing a compound having a polymerizable group and an interactive group is bonded with active species generated on the surface of the substrate while contacting the surface of the substrate on which the polymerization initiating layer is formed.
The contact may be performed by immersing the base material in a liquid composition containing a compound having a polymerizable group and an interactive group, but will be described later from the viewpoint of handling properties and production efficiency. As described above, a layer mainly composed of a composition containing a compound having a polymerizable group and an interactive group may be formed on the substrate surface by a coating method.

<Method of Utilizing Coupling Reaction between Functional Group Present on Substrate Surface and Reactive Functional Group of Polymer Compound at End or Side Chain>
In the present invention, any reaction can be used as a coupling reaction applicable to the production of the graft polymer. Specific combinations of the functional group on the substrate surface and the reactive functional group that the polymer compound has at its terminal or side chain include (—COOH, amine), (—COOH, aziridine), (—COOH, isocyanate. ), (—COOH, epoxy), (—NH ₂ , isocyanate), (—NH ₂ , aldehydes), (—OH, alcohol), (—OH, halogenated compound), (—OH, amine), ( -OH, an acid anhydride) combination. From the viewpoint of high reactivity, (—OH, polyvalent isocyanate) and (—OH, epoxy) are particularly preferred combinations.

<Method of direct photo-graft polymerization of substrate>
(Monomer having an interactive group and photografting)
In the present invention, examples of the compound having an interactive group and directly chemically bonded to the substrate, which are used when a graft polymer is formed by a method of directly photografting a substrate, include the following monomers. For example, (meth) acrylic acid or its alkali metal salt and amine salt, itaconic acid or its alkali metal salt and amine salt, 2-hydroxyethyl (meth) acrylate, (meth) acrylamide, N-monomethylol (meth) acrylamide, N-dimethylol (meth) acrylamide, allylamine or its hydrohalide, 3-vinylpropionic acid or its alkali metal salt and amine salt, vinylsulfonic acid or its alkali metal salt and amine salt, 2-sulfoethyl (meth) acrylate , Polyoxyethylene glycol mono (meth) acrylate, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphooxypolyoxyethylene glycol mono (meth) acrylate, N-vinylpyrrolidone, etc. Examples thereof include monomers having a functional group such as a carboxyl group, a sulfonic acid group, a phosphoric acid group, an amino group or a salt thereof, a hydroxyl group, an amide group, a phosphine group, an imidazole group, a pyridine group, or a salt thereof, and an ether group. . These monomers may be used individually by 1 type, and may use 2 or more types together.

(Polymer having interactive groups and directly chemically bonded to the substrate)
Examples of the polymer having an interactive group and directly chemically bonded to the substrate include a polymer formed from a monomer having an interactive group. In addition, homopolymers and copolymers obtained by using at least one selected from monomers having interactive groups, ethylene addition polymerizable unsaturated groups such as vinyl groups, allyl groups and (meth) acryl groups as polymerizable groups It is more preferable to use a polymer into which (polymerizable group) is introduced, that is, a polymer having a polymerizable group and an interactive group. The polymer having a polymerizable group and an interactive group is one having a polymerizable group at least at the terminal or side chain, particularly preferably having a polymerizable group at the terminal, and further polymerizable at the terminal and side chain. Those having a group are preferred.
Thus, in the present invention, the polymer having a polymerizable group and an interactive group is preferably used for the following reason. That is, in consideration of workability when performing graft polymerization using a monomer, mass production is difficult by the method of immersing in a monomer solution. Further, in the method of applying the monomer solution, it is very difficult to keep the monomer solution uniformly on the substrate before the light irradiation. Furthermore, although a method of covering with a film or the like after coating the monomer solution is known, it is difficult to cover the film uniformly, and the work becomes complicated, such as the need to cover. On the other hand, when a polymer is used, it becomes a solid after coating, so that a uniform film can be formed and mass production is easy.

  Examples of the monomer having an interactive group for synthesizing the polymer include the following monomers. For example, (meth) acrylic acid or its alkali metal salt and amine salt, itaconic acid or its alkali metal salt and amine salt, 2-hydroxyethyl (meth) acrylate, (meth) acrylamide, N-monomethylol (meth) acrylamide, N-dimethylol (meth) acrylamide, allylamine or its hydrohalide, 3-vinylpropionic acid or its alkali metal salt and amine salt, vinylsulfonic acid or its alkali metal salt and amine salt, 2-sulfoethyl (meth) acrylate , Polyoxyethylene glycol mono (meth) acrylate, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphooxypolyoxyethylene glycol mono (meth) acrylate, N-vinylpyrrolidone, etc. Examples thereof include monomers having a functional group such as a carboxyl group, a sulfonic acid group, a phosphoric acid group, an amino group or a salt thereof, a hydroxyl group, an amide group, a phosphine group, an imidazole group, a pyridine group, or a salt thereof, and an ether group. . These monomers may be used individually by 1 type, and may use 2 or more types together.

A polymer having a polymerizable group and an interactive group can be synthesized as follows.
As synthesis methods, i) a method in which a monomer having an interactive group and a monomer having a polymerizable group are copolymerized, and ii) a monomer having an interactive group and a monomer having a double bond precursor are copolymerized. And then introducing a double bond by treatment with a base or the like, iii) reacting a polymer having an interactive group with a monomer having a polymerizable group to introduce a double bond (introducing a polymerizable group) ) Method. From the viewpoint of synthesis suitability, ii) a method in which a monomer having an interactive group and a monomer having a double bond precursor are copolymerized and then a double bond is introduced by treatment with a base or the like, iii This is a method of introducing a polymerizable group by reacting a polymer having an interactive group with a monomer having a polymerizable group.

  As the monomer having an interactive group used for the synthesis of a polymer having a polymerizable group and an interactive group, the same monomers as those having the above interactive group can be used. A monomer may be used individually by 1 type and may use 2 or more types together.

Examples of the monomer having a polymerizable group to be copolymerized with a monomer having an interactive group include allyl (meth) acrylate and 2-allyloxyethyl methacrylate.
Examples of the monomer having a double bond precursor include 2- (3-chloro-1-oxopropoxy) ethyl methacrylate, 2- (3-bromo-1-oxopropoxy) ethyl methacrylate, and the like.

  Furthermore, the polymerizability used for introducing an unsaturated group by utilizing a reaction with a functional group such as a carboxyl group, an amino group or a salt thereof, a hydroxyl group, and an epoxy group in a polymer having an interactive group. Examples of the monomer having a group include (meth) acrylic acid, glycidyl (meth) acrylate, allyl glycidyl ether, and 2-isocyanatoethyl (meth) acrylate.

In the present invention, a macromonomer can also be used. The method for producing the macromonomer used in the present invention is described in, for example, Chapter 2 of “Macromonomer Chemistry and Industry” (editor, Yuya Yamashita) published on September 20, 1999, published by IPC Publishing Bureau. Various production methods have been proposed in “Synthesis”. Particularly useful macromonomers used in this embodiment include macromonomers derived from carboxyl group-containing monomers such as acrylic acid and methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, vinylstyrenesulfonic acid, And sulfonic acid macromonomer derived from a monomer of the salt thereof, (meth) acrylamide, N-vinylacetamide, N-vinylformamide, amide macromonomer derived from N-vinylcarboxylic acid amide monomer, hydroxyethyl methacrylate Macromonomer derived from hydroxyl group-containing monomers such as cocoon, hydroxyethyl acrylate, glycerol monomethacrylate, methoxyethyl acrylate, methoxy polyethylene glycol acrylate, polyethylene glycol Acrylate macromonomers derived from alkoxy group or ethylene oxide group-containing monomers such as. A monomer having a polyethylene glycol chain or a polypropylene glycol chain can also be usefully used as the macromonomer used in the present invention.
Among these macromonomers, the useful molecular weight is in the range of 250 to 100,000, and the particularly preferable range is 400 to 30,000.

The solvent used in the above-mentioned monomer having an interactive group or a composition containing a polymerizable group and a polymer having an interactive group is the main component of the composition, the monomer having an interactive group, polymerizable There is no particular limitation as long as a compound having a group and an interactive group can be dissolved. A surfactant may be further added to the solvent.
Examples of the solvent that can be used include alcohol solvents such as methanol, ethanol, propanol, ethylene glycol, glycerin and propylene glycol monomethyl ether, acids such as acetic acid, ketone solvents such as acetone and cyclohexanone, amides such as formamide and dimethylacetamide. System solvents, and the like.

The surfactant that can be added to the solvent as needed may be any that dissolves in the solvent. Examples of such surfactants include an anionic surfactant such as sodium n-dodecylbenzenesulfonate. Agents, cationic surfactants such as n-dodecyltrimethylammonium chloride, polyoxyethylene nonylphenol ether (commercially available products include, for example, Emulgen 910, manufactured by Kao Corporation), polyoxyethylene sorbitan monolaurate (commercially available) Examples of the product include a trade name “Tween 20” and the like, and nonionic surfactants such as polyoxyethylene lauryl ether.
When the composition is brought into contact in a liquid state, it can be carried out arbitrarily, but the coating amount when forming the interactive group-containing composition coating layer by a coating method is sufficient for interaction with metal ions and the like. sex, and, from the viewpoint of obtaining a uniform coating film is preferably 0.1 to 10 g / ^{m 2} in terms of solid content, in particular 0.5 to 5 g / ^{m 2} is preferred.

(Energy provision)
As a method for applying energy to the substrate surface, for example, radiation irradiation such as heating or exposure can be used. For example, light irradiation with a UV lamp, visible light, or the like, heating with a hot plate, or the like is possible.
Among the above, the energy is desirable in that it suppresses the occurrence of additional polymerization of the graft polymer due to the heat treatment, which is essential in the electric wiring board forming process (manufacturing process of the substrate with the metal film), and the accompanying change in physical properties of the graft polymer. From the viewpoint that the polymer layer can be formed only at the location, light is preferred.
Examples of the light source include a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, and a carbon arc lamp. Examples of radiation include electron beams, X-rays, ion beams, and far infrared rays. Also, g-line, i-line, deep-UV light, and high-density energy beam (laser beam) are used.
Specific examples generally used include direct image-like recording using a thermal recording head, scanning exposure using an infrared laser, high-illuminance flash exposure such as a xenon discharge lamp, and infrared lamp exposure.
The time required for applying energy is usually between 10 seconds and 5 hours, although it varies depending on the amount of the graft polymer produced and the light source.

  By the step (a1) described above, a polymer layer (graft polymer layer) made of a polymer having an interactive group can be formed on the substrate.

[(B) Metal ion application step]
In the step (b), a metal ion or a metal salt is imparted to the polymer layer formed in the step (a). In this process, the interactive group which the graft polymer which comprises a polymer layer has adheres the metal ion or metal salt provided according to the function (adsorption).

(Metal ion or metal salt)
The metal salt is not particularly limited as long as it is dissolved in a suitable solvent to be applied to the polymer layer and dissociated into a metal ion and a base (anion), and M (NO ₃ ) n, MCln, M _{2 / n} (SO ₄ ), M _{3 / n} (PO ₄ ) (M represents an n-valent metal atom), and the like. As a metal ion, the thing which said metal salt dissociated can be used suitably.
As the metal of the metal ion or metal salt in the present invention, silver, palladium, copper, nickel, aluminum, iron, Co, gold and It is preferably one or more metals selected from the group consisting of Cr, more preferably one or more metals selected from the group consisting of silver, palladium, copper, nickel, aluminum, iron, and Cr, More preferably, it is one or more metals selected from the group consisting of silver, copper, and palladium.

(Method for applying metal ions and metal salts)
The method for imparting metal ions or metal salts can be appropriately selected depending on the compound forming the graft polymer constituting the polymer layer. The graft polymer preferably has a hydrophilic group from the viewpoint of adhesion of metal ions and the like. Specifically, the hydrophilic group is preferably a carboxyl group, a sulfonyl group, or a hydroxyl group.
As a method of providing a specific metal ion or metal salt,
(I) When the graft polymer has an ionic group (polar group) as an interactive group, a method of adsorbing metal ions to the ionic group of the graft polymer, (ii) The graft polymer is polyvinyl pyrrolidone or the like A method of impregnating the graft polymer with a metal salt or a solution containing a metal salt when the polymer has a high affinity for the metal salt;
(Iii) Either a solution containing a metal salt in a hydrophilic graft polymer or a method in which a solution containing a metal ion and / or a metal salt is impregnated in a solution in which the metal salt is dissolved. Any of these methods can be appropriately selected and used. In particular, according to the method (iii), since the nature of the graft polymer is not particularly limited, a desired metal ion or metal salt can be imparted.

  When applying a metal ion or a metal salt to the polymer layer (i) when the graft polymer has an ionic group and a method of adsorbing the metal ion to the ionic group, the above metal salt is appropriately used. The solution containing metal ions dissolved and dissociated with a solvent may be applied to the substrate surface on which the polymer layer is formed, or the substrate on which the polymer layer is formed may be immersed in the solution. By contacting a solution containing metal ions, metal ions can be ionically adsorbed to the ionic group. From the viewpoint of sufficient adsorption, the metal ion concentration or the metal salt concentration of the solution to be contacted is preferably in the range of 1 to 50% by mass, and more preferably in the range of 10 to 30% by mass. preferable. The contact time is preferably about 10 seconds to 24 hours, more preferably about 1 minute to 180 minutes.

  When applying a metal ion or metal salt to the polymer layer, (ii) if the graft polymer is a polymer having a high affinity for the metal salt such as polyvinylpyrrolidone, the above metal salt is directly attached in the form of fine particles. Or a dispersion is prepared using a suitable solvent in which the metal salt can be dispersed, and the dispersion is applied to the substrate surface on which the polymer layer is formed, or the polymer layer is formed in the solution. The substrate may be immersed. Further, when the graft polymer is made of a hydrophilic compound, the graft polymer has high water retention, so that the graft polymer can be impregnated with the dispersion in which the metal salt is dispersed using the high water retention. From the viewpoint of sufficiently impregnating the dispersion, the metal salt concentration or the metal salt concentration of the dispersion to be contacted is preferably in the range of 1 to 50% by mass, and in the range of 10 to 30% by mass. More preferably. The contact time is preferably about 10 seconds to 24 hours, more preferably about 1 minute to 180 minutes.

  When applying a metal ion or metal salt to the graft polymer, (iii) immersing a glass substrate having a polymer layer made of a hydrophilic graft polymer in a solution containing the metal salt or a solution in which the metal salt is dissolved, When the method of impregnating the polymer layer with a solution containing metal ions and / or metal salts is used, a dispersion is prepared using an appropriate solvent in which the metal salts can be dispersed, or the metal salts described above are used. Is dissolved in a suitable solvent and a solution containing dissociated metal ions is prepared, and the dispersion or solution is applied to the surface of the substrate having a polymer layer, or a substrate having a polymer layer in the solution is prepared. What is necessary is just to immerse. Also in this method, similarly to the above, the hydrophilic graft polymer can be impregnated with the dispersion or solution by utilizing the high water retention property of the hydrophilic graft polymer. From the viewpoint of sufficient impregnation of the dispersion or solution, the metal salt concentration or the metal salt concentration of the dispersion to be contacted is preferably in the range of 1 to 50% by mass, and in the range of 10 to 30% by mass. More preferably. The contact time is preferably about 10 seconds to 24 hours, more preferably about 1 minute to 180 minutes.

-Relationship between polarity of interactive group (functional group) of graft polymer and metal ion or metal salt-
If the graft polymer has a functional group having a negative charge, a metal ion having a positive charge is adsorbed on the graft polymer, and the adsorbed metal ion is reduced to form a simple metal (metal film or metal fine particle). A depositing region is formed.

-Relationship between the polarity of a hydrophilic group of a hydrophilic compound binding type and a metal ion or metal salt-
When the graft polymer has an anionic property such as a carboxyl group, a sulfonic acid group, or a phosphonic acid group as a hydrophilic functional group as described in detail above, the graft polymer selectively has a negative charge, A metal ion having a positive charge is adsorbed here, and the adsorbed metal ion is reduced to form a metal (fine particle) film region (for example, a wiring).
On the other hand, when the graft polymer chain has a cationic group such as an ammonium group described in JP-A-10-296895, it selectively has a positive charge, and a solution containing a metal salt therein, Alternatively, a metal (fine particle) film region (wiring) is formed by impregnating a solution in which a metal salt is dissolved and reducing metal ions in the impregnated solution or metal ions in the metal salt.
It is preferable from the viewpoint of durability that these metal ions are bonded in the maximum amount that can be imparted (adsorbed) to the hydrophilic group on the hydrophilic surface.

  As a method for imparting a metal ion to a hydrophilic group, a method in which a solution in which a metal ion or a metal salt is dissolved or dispersed is applied to the support surface, and the support surface is immersed in these solutions or dispersions. The method etc. are mentioned. In both cases of coating and dipping, an excessive amount of metal ions is supplied and introduced by sufficient ionic bonding between the hydrophilic group and the contact time between the solution or dispersion and the support surface. Is preferably about 10 seconds to 24 hours, more preferably about 1 minute to 180 minutes.

The metal ion or metal salt is not limited to one type, and a plurality of types can be used in combination as required. In order to obtain desired conductivity, a plurality of materials can be mixed and used in advance.
The metal (reduced metal) formed in this step confirms that fine metal particles are firmly dispersed in the surface graft film from surface observation and cross-sectional observation by SEM and AFM. The size of the metal fine particles to be formed is about 10 nm to 0.1 nm in particle size.

[(C) Metal production step]
In step (c), metal ions or metal salts imparted to the polymer layer in step (b) are reduced with a reducing agent to generate a metal.
The reduction using the reducing agent may be performed by reducing with an aqueous solution containing a reducing agent in the metal ion or metal salt imparted to the polymer layer, or by using an electroless plating solution containing a reducing agent in step (d) described later. Reduction may produce a metal. These will be described below.

(Reducing agent)
In this step, the metal salt present by adsorbing or impregnating the graft polymer, or the reducing agent for reducing the metal ion, is particularly suitable as long as it has physical properties to reduce the metal salt compound used and deposit the metal. There is no restriction | limiting, For example, hypophosphite, tetrahydroborate, hydrazine etc. are mentioned.
These reducing agents can be appropriately selected in relation to the metal salt and metal ion to be used. For example, when a silver nitrate aqueous solution is used as the metal salt aqueous solution for supplying the metal ion or metal salt, tetrahydroboron is used. When sodium acid uses an aqueous palladium dichloride solution, hydrazine is preferred.

As a method for adding the reducing agent, for example, (1) a substrate having a polymer layer is provided with metal ions or metal salts, washed with water to remove excess metal salts and metal ions, and then the substrate is subjected to ion exchange. Examples include a method of immersing in water such as water and adding a reducing agent thereto, and (2) a method of directly applying or dropping a reducing agent aqueous solution having a predetermined concentration on the substrate surface.
(3) As the addition amount of the reducing agent, it is preferable to use an excess amount equal to or more than the metal ion, and more preferably 10 times equivalent or more.

  The presence of uniform and high-strength reduced metal due to the addition of a reducing agent can be visually confirmed by the metallic luster of the surface, but the surface is observed using a transmission electron microscope or AFM (atomic force microscope). By doing so, the structure can be confirmed. The metal (fine particle) film can be easily formed by a conventional method, for example, a method of observing the cut surface with an electron microscope.

(Reduced metal generation using electroless plating)
In the step (c), it is also preferable to apply an electroless plating solution containing a reducing agent to the polymer layer to reduce the metal ion or metal salt to a metal.
In this case, it is preferable to perform the below-mentioned (d) process continuously.
It is also preferable to form a plating film having a surface resistivity of 0.01 to 1Ω / □ by performing electroless plating simultaneously with the reduction using the metal as an electroless plating catalyst.

[(D) Plating film forming step]
In step (d), an electroless plating solution is applied to the polymer layer, and electroless plating is performed to form a plating film.
In step (d), as described in (c) above, an electroless plating solution containing a reducing agent is applied to the polymer layer, and the metal ions or metal salts are reduced to metal at the same time as the electroless plating catalyst. It is preferable to form a plating film having a surface resistivity of 0.01 to 1Ω / □ by performing electroless plating.
<Electroless plating>
Electroless plating refers to an operation in which a metal is deposited by a chemical reaction using a solution in which metal ions to be plated are dissolved.
Application of the electroless plating solution in the step (c) is, for example, in the step (b), after applying metal ions or metal salts to the polymer layer, washing with water to remove excess metal salts and the like and plating. It is preferable to immerse in an electroless plating bath containing metal ions and a surface charge control agent. As components other than the surface charge control agent that can be used as the electroless plating bath, generally known components of the electroless plating bath can be used.

The composition of a general electroless plating bath is as follows: 1. metal ions to be plated, 2. reducing agent; Additives (stabilizers) that improve the stability of metal ions are mainly included. Contains a surface charge control agent. In addition to these, the plating bath may contain known additives such as other stabilizers for the plating bath.
Copper, tin, lead, nickel, gold, palladium, and rhodium are known as the types of metals used in the electroless plating bath. Among these, copper and gold are particularly preferable from the viewpoint of conductivity.
In addition, there are optimum reducing agents and additives according to the above metals. For example, a copper electroless plating bath contains Cu (SO ₄ ) ₂ as a copper salt, HCHO as a reducing agent, and a chelating agent such as EDTA or Rochelle salt which is a copper ion stabilizer as an additive. The plating bath used for electroless plating of CoNiP includes cobalt sulfate and nickel sulfate as metal salts, sodium hypophosphite as a reducing agent, sodium malonate, sodium malate and sodium succinate as complexing agents. It is included. Further, the electroless plating bath of palladium contains (Pd (NH ₃ ) ₄ ) Cl ₂ as metal ions, NH ₃ and H ₂ NNH ₂ as reducing agents, and EDTA as a stabilizer. These plating baths may contain components other than the above components.
When reducing the metal ions or metal salts present in the graft polymer layer using the electroless plating solution, the plating rate is preferably slow in order to sufficiently reduce the metal ions or metal salts.
As the electroless plating conditions, the electroless plating solution temperature and the contact time are preferably 30 to 60 ° C. and 1 to 10 minutes, and 40 to 60 ° C. and 3 to 8 minutes in order to sufficiently perform the above reduction. More preferably, 45 to 55 ° C. and 3 to 5 minutes are particularly preferable.
The flow rate (stirring speed, bubbling) is preferably 0.1 to 10 liters / minute, more preferably 0.5 to 8 liters / minute, and 1 to 6 liters / minute with respect to 1 liter of the electroless plating bath. Is particularly preferred.

[(E) Metal film formation process by electroplating]
In the step (e), a metal film is formed on the plating layer by electroplating following the step (d). Thereby, while being excellent in adhesiveness with a board | substrate, the metal film which can be equipped with sufficient electroconductivity is formed.

As a method of electroplating, a conventionally known method can be used.
Examples of the metal used for electroplating in this step include copper, chromium, lead, nickel, gold, silver, tin, and zinc. From the viewpoint of conductivity, copper, gold, and silver are preferable, and copper is more preferable. .

The electroplating bath used for the electroplating in this step preferably contains an additive from the viewpoint of improving characteristics when used as an electronic circuit such as smoothness, spreadability, and conductivity of the metal film.
As an additive in electroplating, a commercially available additive for electroplating can be used. Specific examples of the additive include Janus Green B (JGB), SPS (sulfopropyl thiolate), polyethylene glycol, and various surfactants. In addition, as a mixture of these products, each manufacturer of plating solutions includes Capper Gream series manufactured by Meltex, Top Lucina series manufactured by Okuno Pharmaceutical Co., Ltd., Cube Light Series manufactured by Ebara Eugelite, etc. Can be used.
However, what is necessary is just to select the thing according to the mechanical characteristic etc. of the metal film obtained.
About the specific aspect of the kind of additive, and its addition amount, it can adjust suitably considering various characteristics, such as an electroplating speed | rate, the current density at the time of electroplating, and the internal stress of the metal film formed. Specifically, the chemical concentration of the additive may be 0.1 mg / L to 1.0 g / L, and in the case of a commercially available electroplating solution, 1 ml / L to 50 ml / L may be added.

The electroplating in the step (e) is performed at a current density of 0.1 to 3 mA / cm ² until the amount of electricity from the start of energization reaches 1/10 to 1/4 of the amount of electricity required until the end of energization. It is preferable to do so. By performing electroplating in this process at a small current density for a certain period from the beginning of energization, a metal film can be uniformly formed on a substrate with a relatively high surface resistance, and at the same time, a metal film grows slowly, A dense metal film having excellent electric conductivity and suitable for an electronic circuit can be formed.
During the period of electroplating at a current density in the above range, the amount of electricity from the start of energization is 1/10 to 1/1 of the amount of electricity required until the end of energization depending on the properties and applications of the metal film to be formed. It is appropriately set until 4 is reached. Further, the magnitude of the current density is appropriately set within the above range according to the use and properties of the formed metal film.
The electroplating in this step is performed by increasing the current density after a predetermined period of time with a small current density in the above range. The degree of increase in current density can be set as appropriate, but is usually 2 to 20 times, preferably about 3 to 5 times the current density at the start of energization.
There are no particular restrictions on the mode of increase in current density, and modes such as an increase in line shape, an increase in steps, and an exponential increase can be adopted. From the viewpoint of the uniformity of the plating film, it is preferable to increase the current density in a linear shape.

  The film thickness of the metal film formed by electroplating varies depending on the application, and can be controlled by adjusting the concentration of metal contained in the plating bath, the immersion time, or the current density. . In addition, from the viewpoint of conductivity, the film thickness when used for general electric wiring or the like is preferably 0.3 μm or more, and more preferably 3 μm or more.

The surface resistivity of the metal film formed by the step (e) is preferably 1 × 10 ⁻¹ Ω / □ or less, more preferably 1 × 10 ⁻² Ω / □ or less.

  In addition, the surface resistivity in this specification is a value measured by a 4-instrument 4-probe method and a constant current application method using a resistivity meter, Loresta EP / MCP-T360 type manufactured by Dia Instruments Co., Ltd. It was adopted.

[(F) Heat treatment step]
In the step (f), following the steps (d) and (e), the substrate on which the plating film is formed is heat-treated at a temperature of 100 ° C. or higher and 200 ° C. or lower. By this heat treatment step at a specific temperature, the adhesion between the metal thin film and the plating film and the substrate is unexpectedly strengthened.
The mechanism of this effect is not clear, but is presumed as follows.
That is, the metal nanocomposite layer inherent in the graft polymer layer has a depth of 50 to 200 nm from the surface, and is heat-treated at the temperature, thereby densifying the polymer structure by self-crosslinking inside the graft polymer, It is considered that the nanocomposite is a layer having a metal nanoanchor function having an extremely strong adhesion by re-forming the structure as an anchor in the graft layer, and a strong adhesion is ensured.
Even if this structure without the metal nanocomposite layer is heat-treated, the adhesion force cannot be improved, so that the metal having the metal nano-anchor function of the metal nanocomposite layer contained in the graft polymer layer is stabilized by the heat treatment. It is presumed that the adhesion is improved by immobilization or growth. The heat treatment may be performed after step (d) or after step (e). However, in the case of a metal film that is easily oxidized such as copper, nitrogen, argon, or the like is used to suppress metal oxidation. It is particularly preferable to perform the heat treatment in an inert gas atmosphere.

The temperature in the heat treatment needs to be 100 to 200 ° C., but is preferably 120 ° C. or more and 200 ° C. or less, and 140 ° C. or more and 140 ° C. or more from the viewpoint of re-forming the nanocomposite metal structure in the graft polymer layer. It is more preferably 200 ° C. or lower, and particularly preferably 160 ° C. or higher and 170 ° C. or lower.
Moreover, although the time which performs the said heat processing can be suitably selected according to temperature conditions, generally 10 to 120 minutes are preferable, 30 to 90 minutes are more preferable, and 30 to 60 minutes are especially preferable.
Further, the heat treatment may be performed under reduced pressure or normal pressure, or may be performed under pressure, and the heat treatment is performed in an inert gas atmosphere such as nitrogen or argon in order to suppress metal oxidation. Things are preferable.

  As an apparatus for performing the heat treatment, a known apparatus such as an electric heating drier, a decompression drier, a clean oven, a gas displacement drier or a heating furnace, a baking furnace, and the like can be used. Under the conditions, it is preferable to use a gas displacement dryer, a heating furnace, or a baking furnace.

In the present invention, a step of forming a metal pattern by etching the plating film or the metal film is provided after any one of the steps (d), (f), and (e). be able to.
[Process for forming a metal pattern by etching a plating film or a metal film]
As the etching method for forming the metal pattern by etching the plating film or the metal film obtained by the present invention, “subtractive method” and “semi-additive method” are used.

"Subtractive method"
The subtractive method is (1) forming a resist layer by coating or laminating on the plating film or metal film prepared by the above method → (2) forming a resist pattern of a conductor to be left by pattern exposure and development → (3) Etching removes unnecessary plating film or metal film → (4) A method of peeling a resist layer and forming a metal pattern. The thickness of the plating film or metal film used in this embodiment is preferably 5 μm or more, and more preferably in the range of 5 to 30 μm.

(1) Resist layer coating step resist As the photosensitive resist to be used, a photocurable negative resist or a photodissolvable positive resist that dissolves upon exposure can be used. As the photosensitive resist, 1. photosensitive dry film resist (DFR); 2. liquid resist; An ED (electrodeposition) resist can be used. Each of these has its own characteristics. 1. A photosensitive dry film resist (DFR) can be used in a dry manner, so that it is easy to handle. Since the liquid resist can have a thin film thickness as a resist, a pattern with good resolution can be formed. 3. Since an ED (electrodeposition) resist can have a thin film thickness as a resist, it can form a pattern with good resolution, has good follow-up to unevenness on the coated surface, and has excellent adhesion. The resist to be used may be appropriately selected in consideration of these characteristics.

Application method 1. Photosensitive dry film The photosensitive dry film generally has a sandwich structure sandwiched between a polyester film and a polyethylene film, and is pressure-bonded with a hot roll while peeling the polyethylene film with a laminator.
The photosensitive dry film resist is described in detail in Japanese Patent Application Laid-Open No. 2006-284842, paragraphs [0192] to [0372], for the formulation, film forming method, and laminating method. Can be applied.
2. Liquid resist coating methods include spray coating, roll coating, curtain coating, and dip coating. In order to apply both surfaces simultaneously, roll coating and dip coating are preferable because both surfaces can be coated simultaneously.
The liquid resist is described in detail in Japanese Patent Application No. 2005-188722, paragraph numbers [0199] to [0219] previously proposed by the applicant of the present application, and these descriptions can be applied to the present invention.

3. ED (Electrodeposition) Resist ED resist is a colloid obtained by suspending photosensitive resist in fine particles and suspending in water. Since the particles are charged, when a voltage is applied to the conductor layer, A resist can be deposited on the conductor layer, and the colloid can be coated on the conductor to form a film.

(2) Pattern exposure process "Exposure"
A base material provided with a resist film on the upper part of the metal film is brought into close contact with a mask film or a dry plate, and exposed to light in a photosensitive region of the resist used. In the case of using a film, the film is exposed with a vacuum printing frame. Regarding the exposure source, a point light source can be used when the pattern width is about 100 μm. When forming a pattern having a pattern width of 100 μm or less, it is preferable to use a parallel light source.
"developing"
Any photo-curing negative resist can be used as long as it can dissolve the unexposed area, or a photo-dissolvable positive resist that dissolves upon exposure, so long as it dissolves the exposed area. An aqueous solution is used. In recent years, an alkaline aqueous solution has been used in order to reduce environmental burden.

(3) Etching process "Etching"
Etching is a process for forming a conductor pattern by chemically dissolving an exposed metal layer without a resist. The etching process is mainly performed by a horizontal conveyor device by spraying an etching solution from above and below. As the etchant, the metal layer is oxidized and dissolved with an oxidizing aqueous solution. Examples of etching solutions include ferric chloride solution, cupric chloride solution, and alkali etchant. Since the resist may be peeled off by alkali, a ferric chloride solution and a cupric chloride solution are mainly used.
In the method of the present invention, since the substrate interface is not roughened, the conductive polymer in the vicinity of the substrate interface has good removability, and the graft polymer in which the metal film is introduced onto the base material is a polymer chain. In this etching process, the etchant can easily diffuse into the graft polymer layer because it is bonded to the substrate at the end and has a very high mobility structure, and the interface between the substrate and the metal layer. Since the metal component is easily removed from the portion, it is possible to form a pattern with excellent sharpness.

(4) Resist peeling process “Peeling process”
After the metal (conductive) pattern is completed by etching, the etching resist that is no longer needed is no longer needed, and a process of peeling it off is necessary. Peeling can be performed by spraying a stripping solution. The stripping solution varies depending on the type of resist, but generally, a solvent or solution that swells the resist is wiped with a spray, and the resist is swollen and stripped.

"Semi-additive method"
The semi-additive method is: (1) coating a resist layer on a metal film formed on a graft polymer → (2) forming a resist pattern of a conductor to be removed by pattern exposure and development → (3) removing the resist by plating. Forming a metal film on the pattern portion → (4) Stripping DFR → (5) A metal pattern forming method of removing an unnecessary metal film by etching. In these steps, the same technique as the “subtractive method” can be used. As the plating method, electroless plating or electroplating described above can be used. In addition, the thickness of the metal film used is preferably about 1 to 3 μm in order to complete the etching process in a short time. Moreover, you may perform electrolytic plating and electroless plating further with respect to the formed metal pattern.
By such an etching method, a conductive pattern material using the conductive material obtained in the present invention can also be obtained. Since the conductive material obtained by the present invention has a highly adhesive metal film formed on a smooth substrate, etching forms a fine metal pattern with high adhesion on a smooth substrate. Useful for forming electrical circuits.

As described above, by using the laminate of the present invention, a printed wiring board having excellent characteristics can be easily formed on an arbitrary solid surface. That is, without roughening the surface of the insulating resin material layer having heat resistance and low dielectric constant such as epoxy resin, polyimide resin, liquid crystalline resin, polyarylene resin, etc. used as a substrate in the printed wiring board field, A metal film material exhibiting high adhesion strength, for example, a copper-clad laminate can be obtained.
Using a conductive material such as a copper-clad laminate obtained by the production method of the present invention, for example, by a known etching process, the fineness of 20 microns or less, which has been difficult with conventional techniques, and adhesion strength High copper wiring can be formed.

[Printed wiring board]
The substrate with a metal film manufactured by the manufacturing method of the present invention is formed by forming a conductive layer (wiring) on the substrate using a known metal pattern forming method such as the etching method described above, can do.
A printed wiring board manufactured using a substrate with a metal film manufactured by the manufacturing method of the present invention has high adhesion to the substrate and is provided with a fine and high-density conductive layer (wiring) and is conductive. Since it is excellent in insulation between the conductive layers (wirings), a short circuit or the like does not occur even though the wiring is fine, and the printed wiring board is highly reliable.
As a board | substrate which can be used for the printed wiring board in this invention, the well-known laminated board used in a normal wiring board, for example, glass cloth-epoxy resin, paper-phenol resin, paper-epoxy resin, glass cloth / glass paper-epoxy Resin etc. can be used and there is no restriction in particular. Further, a BT substrate impregnated with a bismaleimide-triazine resin, a polyimide film substrate using a polyimide film as a base material, and the like can also be used.

  A printed wiring board manufactured using a substrate with a metal film manufactured by the manufacturing method of the present invention is obtained by building up an insulating material layer or an electric circuit board formed on the insulating material layer. It can also be.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

(Example 1)
(Intermediate layer (graft initiation layer))
jER806 (Bisphenol F type epoxy resin: manufactured by Japan Epoxy Resin) 11.9 parts by mass, LA7052 (Phenolite, curing agent: Dainippon Ink and Chemicals) 4.7 parts by mass, YP50-35EK (phenoxy resin, filler: Toto 21.7 parts by mass of Kasei Chemical Co., Ltd.), 61.6 parts by mass of cyclohexanone, and 0.1 parts by mass of 2-ethyl-4-methylimidazole (curing accelerator) were mixed to prepare a coating solution, and a filter cloth (material) : Polytetrafluoroethylene, mesh # 200), and the coating solution was applied onto GX-13 (ABF, manufactured by Ajinomoto Co., Inc.) in which an interlayer insulating film was laminated on a glass epoxy substrate with a spin coater. . Thereafter, it was dried and cured at 170 ° C. for 60 minutes. The thickness of the cured film was 0.5 μm.

(Graft polymer layer)
7.8 parts by weight of the graft polymer precursor composed of the following compound 1 was dissolved in a solution consisting of 21.7 parts by weight of distilled water, 31.4 parts by weight of acetonitrile, and 39.1 parts by weight of a 10% diluted DMAc solution. The mixture was filtered through (material polytetrafluoroethylene, mesh # 420), and the coating solution was applied onto the intermediate layer (graft initiation layer) with a spin coater. Then, it was dried at 80 ° C. for 5 minutes, and irradiated for 377 seconds at a wavelength of 254 nm and an intensity of 3.5 mmW / cm ² (ultraviolet irradiation device, UNICURE UVX-02516S1LP01, manufactured by USHIO INC.) To form a graft polymer layer. Formed. The thickness of the formed graft polymer layer was 0.3 μm.

(Electroless plating process)
The substrate obtained in the above step was immersed in distilled water for 5 minutes to dissolve and remove the polymer that was not a graft polymer, and then immersed in a 1% silver nitrate aqueous solution for 1 minute to adsorb the catalyst (Ag).
Thereafter, it was immersed in an electroless plating bath having the following composition for 5 minutes to perform electroless plating to form a copper layer having a thickness of 0.5 μm.

<Composition of electroless plating bath>
・ Distilled water 859g
・ Methanol 850g
・ Copper sulfate 18.1g
・ Ethylenediaminetetraacetic acid disodium salt 54.0g
・ Polyoxyethylene glycol (molecular weight 1000) 0.18g
・ 2,2'-bipyridyl 1.8mg
・ 10% ethylenediamine aqueous solution 7.1g
・ 37% formaldehyde aqueous solution 9.8g
The pH of the plating bath having the above composition was adjusted to 12.5 (60 ° C.) with sodium hydroxide and sulfuric acid.

(Electroplating process)
The material obtained above was subjected to electroplating in the following electroplating bath at a current amount of 0.75 mA / cm ² for 30 minutes. A copper foil having a thickness of 18 μm was formed by electroplating. The obtained substrate with copper foil was heat-treated at the temperature shown in Table 1 for 60 minutes.
The surface resistance after electroplating is shown in Table 1.

<Composition of electroplating bath>
・ Copper sulfate 38g
・ 95 g of sulfuric acid
・ Hydrochloric acid 1mL
・ Copper Greeme PCM (Meltex Co., Ltd.) 3mL
・ Water 500g

(Example 2)
In Example 1, instead of using a glass epoxy substrate, a substrate with copper foil was obtained in the same manner as in Example 1 except that a glass epoxy resin substrate with copper foil was used. The results are shown in Table 1.

(Example 3)
In Example 1, instead of using a glass epoxy substrate, a substrate with copper foil was performed in the same manner as in Example 1 except that a polyimide substrate (product name: Kapton H, manufacturer name: manufactured by Toray DuPont Co., Ltd.) was used. And evaluated similarly. The results are shown in Table 1.

Example 4
In Example 1, instead of using a glass epoxy substrate, a copper foil was obtained in the same manner as in Example 1 except that a polyimide substrate with copper foil (product name: Iupicel N, manufacturer name: Ube Industries, Ltd.) was used. An attached substrate was obtained and evaluated in the same manner. The results are shown in Table 1.

(Comparative Examples 1-4)
Except not performing the heat processing in the electroplating process of Examples 1-4, it performed similarly to Examples 1-4, the board | substrate with a copper foil was obtained, and it evaluated similarly. The results are shown in Table 1.

(Examples 5-6, Comparative Examples 5-6)
In Example 1, it carried out similarly to Example 1 except having made heat processing temperature into the temperature shown in Table 1, the board | substrate with a copper foil was obtained, and evaluated similarly. The results are shown in Table 1.

[Evaluation]
1. Surface Roughness of Graft Polymer Layer The surface roughness Ra of the graft polymer layer, which is a joint surface with the Cu layer, obtained in the examples and comparative examples was changed to Ra of JIS B0601 (revised in 2010120). Based on the above, measurement was performed using Surfcom 3000A (manufactured by Tokyo Seimitsu Co., Ltd.). The measurement results are shown in Table 1 below.

2. Cu film thickness measurement The Cu film formed by electroless plating and the Cu film formed by electroplating obtained in Examples and Comparative Examples were cut perpendicular to the substrate plane using a microtome, The cross section was observed by SEM, and the thickness of the formed Cu film was measured. The measurement represents an average obtained by measuring three points per sample. The measurement results are shown in Table 1 below.

3. Evaluation of adhesion The peel strength of the copper foil was measured at a width of 5 mm and a tensile speed of 10 mm / min for the substrates with copper foil obtained in the examples and comparative examples. The measurement results are shown in Table 1 below.

4). Surface resistance (metal surface after electroplating)
About the board | substrate with copper foil obtained by the Example and the comparative example, the surface resistivity was measured using the surface resistance measuring machine (Loresta EP: Mitsubishi Chemical Corporation make). The measurement results are shown in Table 1 below.

  From the above results, the substrate with the copper foil obtained by the method of the present invention was adhered to the copper foil and the substrate by heat treatment, although the surface roughness of the graft polymer layer in contact with the metal Cu was very small. It turns out that it is excellent in property. On the other hand, it can be seen that the adhesion of the substrate with a copper foil for comparison when the heat treatment is not carried out or outside the scope of the present invention is remarkably inferior.

Claims (9)

(A) forming on the surface of the substrate or the interlayer insulating resin film a polymer layer made of a polymer having a functional group that interacts with a metal ion or metal salt and directly chemically bonded to the substrate or the interlayer insulating resin film; (B) a step of applying a metal ion or metal salt to the polymer layer, (c) a step of reducing the metal ion or metal salt applied to the polymer layer with a reducing agent to generate a metal, and (d) Forming a plating film on the polymer layer using an electroless plating solution; and (f) performing a heat treatment at a temperature of 100 ° C. or more and 200 ° C. or less after the step (d) forming the plating film. A method for producing a substrate with a metal film, comprising: 2. The substrate with a metal film according to claim 1, further comprising: (e) a step of forming a metal film by electroplating between the step (d) of forming the plating film and the step (f) of heat treatment. Manufacturing method. The said metal film contains Cu, The manufacturing method of the board | substrate with a metal film of Claim 2 characterized by the above-mentioned. 4. The polymer layer according to any one of claims 1 to 3, wherein the polymer layer is formed by applying a coating solution containing a graft polymer precursor and then graft-polymerizing the graft polymer precursor by applying energy. The manufacturing method of the board | substrate with a metal film of description. The method of manufacturing a substrate with a metal film according to claim 4, wherein the energy is light. 6. The method for producing a substrate with a metal film according to claim 1, wherein the substrate or the interlayer insulating resin film has an arithmetic average surface roughness Ra of 0.01 to 0.5 μm. The said heat processing temperature is 120 degreeC or more and 200 degrees C or less, The manufacturing method of the board | substrate with a metal film of any one of Claims 1-6 characterized by the above-mentioned. The substrate or the interlayer insulating resin film is at least one selected from silicon, glass, epoxy resin, polyimide resin, polyimide amide resin, liquid crystal polymer, polyether imito resin, polyether ether ketone resin, and aramid resin. The manufacturing method of the board | substrate with a metal film of any one of Claims 1-7 characterized by the above-mentioned. 9. The metal ion metal adsorbed on the polymer layer is at least one selected from the group consisting of Ag, Pd, Cu, Ni, Al, Fe, Co, and Cr. The manufacturing method of the board | substrate with a metal film of 1 item | term.