JP2012054368A - Method of manufacturing multilayer wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method that can manufacture metal wiring having high definition and excellent adhesiveness and manufacture a multilayer wiring board having excellent connection reliability of a via hole with a high yield.SOLUTION: A manufacturing method comprises (A) a step of forming, on the surface of a wiring substrate having a first conducive layer 14, a laminate which contains an insulating layer and an adhesion resin layer 20 achieved by applying energy to a layer containing polymer having predetermined functional groups in this order, (B) a step of applying plating catalyst to the adhesion resin layer and then executing plating on the adhesion resin to form a second conductive layer 24, (C) a step of executing laser processing or drilling to form a via hole 26 so that the via hole 26 penetrates through the second conductive layer and the insulating later and reaches the first conductive layer, (D) a step of executing desmear processing, and (E) a step of applying carbon black or graphite to the wall surface of the via hole and then executing electroplating to electrically connecting the first conductive layer and the second conductive layer to each other without executing electroless plating.

Description

  The present invention relates to a method for manufacturing a multilayer wiring board.

2. Description of the Related Art Conventionally, a metal wiring board in which wiring with a metal pattern is formed on the surface of an insulating substrate has been widely used for electronic components and semiconductor elements.
As a method for producing such a metal pattern material, a “subtractive method” is mainly used. In this subtractive method, a photosensitive layer that is exposed by irradiation with actinic rays is provided on a metal film formed on the surface of the substrate, the photosensitive layer is exposed imagewise, and then developed to form a resist image. In this method, the metal film is etched to form a metal pattern, and finally the resist image is peeled off.

  In the metal pattern obtained by this method, the adhesion between the substrate and the metal film is expressed by an anchor effect generated by providing irregularities on the substrate surface. Therefore, due to the unevenness of the substrate interface part of the obtained metal pattern, the wiring edge part becomes uneven, the wiring thickness cannot be made constant, and it is difficult to obtain the wiring shape as designed, or fine wiring When trying to form, there existed a problem that the part connected with an adjacent wiring was made or the wiring disconnected. In addition, in order to obtain a metal pattern with excellent adhesion between the metal film and the substrate, it is necessary to treat the substrate surface with a strong acid such as chromic acid in order to make the substrate surface uneven. There is a problem that a complicated process is necessary.

  In view of the above circumstances, a method of forming a multilayer wiring board with high connection reliability suitable for forming fine wiring by a semi-additive method is disclosed (Patent Document 1). More specifically, in this document, first, a patterned metal film is formed on the surface of a first wiring substrate having metal wiring via an insulating layer and a polymer adhesion layer, and the patterned A via hole is formed using the metal film as a mask. Next, by applying an electroless plating catalyst to the wall surface of the via hole and performing a plating process such as electroless plating, the metal wiring on the wiring board and the patterned metal film formed on the upper part thereof are connected, Manufactures multilayer wiring boards.

JP 2010-157589 A

On the other hand, in recent years, along with demands for higher functionality of electronic devices, electronic components have been integrated with higher density and further with higher density packaging. Under such circumstances, printed wiring boards and the like for high-density mounting used for these are required to be downsized and high-density, and in order to satisfy such demands, multilayer wiring boards are formed with a fine wiring pitch. In addition, it is more important to be able to electrically connect the wiring patterns of a plurality of layers with high connection reliability.
When the present inventors manufactured a multilayer wiring board using the method described in Patent Document 1, the connection reliability of vias has not reached the level required recently, and further improvement is necessary. Met.

  In recent years, it has been demanded to manufacture a multilayer wiring board with high throughput and high productivity from the viewpoint of reducing manufacturing costs. On the other hand, the method described in Patent Document 1 is not always sufficient from the viewpoint of productivity of producing a practically durable metal film having a large number of steps and excellent adhesion and the like.

  In view of the above circumstances, the present invention can produce a metal wiring with high definition and excellent adhesion, and can produce a multilayer wiring board with excellent via connection reliability with high yield. It aims at providing the outstanding manufacturing method.

As a result of intensive studies in view of the above problems, the present inventor has found that the above object can be achieved by the following means.
(1) (A) Energy is applied to a layer containing a polymer having a functional group and a polymerizable group that form an interaction with an insulating layer and a plating catalyst or a precursor thereof on a wiring board surface provided with a first conductive layer. A step of forming a laminate including the adhesion resin layer obtained in this order, and
(B) After providing the plating resin or precursor thereof to the adhesion resin layer after the step (A), performing plating, and forming a second conductive layer on the adhesion resin layer;
(C) After the step (B), a via hole is formed by laser processing or drilling so as to penetrate the second conductive layer, the adhesion resin layer, and the insulating layer and reach the first conductive layer. And a process of
(D) After the step (C), performing a desmear process;
(E) After the step (D), after applying carbon black or graphite to the wall surface of the via hole, electroplating is performed without performing electroless plating, and the first conductive layer and the second conductive layer And a step of electrically connecting the conductive layer.

(2) The method for manufacturing a multilayer wiring board according to (1), wherein the thickness of the second conductive layer is 0.2 to 20 μm.
(3) The method for producing a multilayer wiring board according to (1) or (2), wherein the functional group that interacts with the plating catalyst or a precursor thereof is a cyano group or a carboxylic acid group.
(4) The method for manufacturing a multilayer wiring board according to any one of (1) to (3), wherein the stacked body further includes an adhesion auxiliary layer between the insulating layer and the adhesion resin layer.

  The present invention provides a manufacturing method excellent in productivity, capable of manufacturing a metal wiring having high definition and excellent adhesion, and capable of manufacturing a multilayer wiring board excellent in via connection reliability at a high yield. can do.

(A)-(D) are typical sectional drawings from the board | substrate which shows each manufacturing process in the manufacturing method of the multilayer wiring board of this invention in order to a multilayer wiring board, respectively. (A)-(E) are typical sectional drawings which show each manufacturing process in order from process (F) to (I). FIG. 6 is a schematic cross-sectional view showing via chains obtained in Examples 1 to 5 and Comparative Examples 1 and 2.

Below, the manufacturing method of the multilayer wiring board of this invention is explained in full detail.
The manufacturing method includes the following five steps.
(A) Applying energy to the insulating substrate and a layer containing a polymer having a functional group and a polymerizable group that interact with the plating catalyst or its precursor on the surface of the wiring board including the first conductive layer. Step of forming a laminate comprising the obtained adhesion resin layer in this order (B) After applying the plating catalyst or its precursor to the adhesion resin layer after the step (A), plating is performed, and the adhesion resin layer is formed. Step (C) of forming the second conductive layer on the first conductive layer after passing through the second conductive layer, the adhesive resin layer, and the insulating layer by laser processing or drilling after the step (B). Step of forming via hole to reach (D) Step of performing desmear treatment after step (C) (E) After step (D), after applying carbon black or graphite to the via hole wall surface, electroless Plating Ukoto without it performs electroplating, a step of electrically connecting the first conductive layer and a second conductive layer

Unlike the method described in Patent Document 1 described above, the manufacturing method of the present invention forms via holes without patterning the adhesive resin layer, and has fewer steps.
Further, as one of the characteristics of the manufacturing method of the present invention, a step of forming a conductive metal film (E) for electrically connecting the first conductive layer and the second conductive layer after the via hole is formed (E ) In which electroplating is performed using carbon black and graphite. By passing through this step, it is advantageous in terms of the yield and durability of interlayer connection.
Hereinafter, each step will be described in order with reference to the drawings.

<Process (A): Laminate formation process>
In the step (A), energy is applied to a layer containing a polymer having a functional group and a polymerizable group that interact with the insulating layer and the plating catalyst or its precursor on the surface of the wiring substrate including the first conductive layer. A laminate including the adhesion resin layer obtained by applying in this order is formed. Usually, the insulating layer and the adhesion resin layer are provided on the entire surface of the wiring substrate surface where these layers are to be formed.
More specifically, as shown in FIG. 1A, in this step, the wiring substrate 10 in which the first conductive layer 14 is formed on the substrate 12 and the insulating layer provided on the wiring substrate 10 are used. 16, a laminate 22 including the adhesion auxiliary layer 18 provided on the insulating layer 16 and the adhesion resin layer 20 provided on the adhesion auxiliary layer 18 is formed.
Hereinafter, the wiring substrate 10, the insulating layer 16, the adhesion auxiliary layer 18, and the adhesion resin layer 20 will be described in detail.

<Wiring board 10>
The wiring board 10 used in the present invention typically includes those formed by a subtractive method using an etching process, and those formed by a semi-additive method using electrolytic plating. You may use what was formed.
More specifically, the wiring board 10 may be a double-sided or single-sided copper-clad laminate (CCL), or a copper-clad laminate made of a copper film in a pattern, which is a flexible substrate. It may be a rigid substrate.

As a material which comprises the board | substrate 12 in the wiring board 10, a glass epoxy material, BT resin, a polyimide film, a polyamide film, a liquid crystal film, an aramid etc. are mentioned, for example. Of these, glass epoxy materials and BT resins are preferred from the viewpoint of thermal or mechanical properties such as dimensional stability and heat resistance.
Examples of the material constituting the first conductive layer 14 include copper, silver, tin, nickel, and gold. Note that the first conductive layer 14 functions as a first metal wiring and may be provided over the entire surface of the substrate 12 or may be formed in a pattern as shown in FIG.

<Insulating layer 16>
The insulating layer 16 is a layer provided to ensure insulation reliability in the multilayer wiring board (for example, between the first conductive layers 14), and the formation method thereof is not particularly limited. More specifically, a method (coating method) for forming an insulating layer 16 by applying an insulating resin composition containing an insulating resin, or an insulating layer 16 containing an insulating resin on the wiring substrate 10. The method of laminating etc. is mentioned.
The thickness of the insulating layer 16 is appropriately selected according to the purpose of use of the multilayer wiring board, but is preferably 5 to 150 μm, and more preferably 10 to 100 μm.
In addition, the “insulating resin” in the present invention means a resin having an insulating property that can be used for a known insulating film or insulating layer, and is not a perfect insulator. In addition, any resin having insulating properties according to the purpose can be applied to the present invention.

Specific examples of the insulating resin may be, for example, a thermosetting resin, a thermoplastic resin, or a mixture thereof. Examples of the thermosetting resin include an epoxy resin, a phenol resin, a polyimide resin, a polyester resin, and a bismaleimide. Examples thereof include resins, polyolefin resins, isocyanate resins and the like.
Examples of the thermoplastic resin include phenoxy resin, polyether sulfone, polysulfone, polyphenylene sulfone, polyphenylene sulfide, polyphenyl ether, polyether imide, and the like.

  The insulating resin composition used for forming the insulating layer may contain a compound such as a compound having a polymerizable double bond in order to promote crosslinking, specifically, an acrylate or methacrylate compound. In particular, polyfunctional ones are preferred.

Furthermore, the insulating resin composition may be provided with a filler (for example, silica, alumina, clay, talc, etc.), a colorant, a flame retardant, an adhesion imparting agent, a silane coupling agent, and an antioxidant as necessary. In addition, one or more of various additives such as an ultraviolet absorber may be added.
When these materials are added to the insulating resin composition, it is preferable to add them in the range of 1 to 200% by mass, and more preferably in the range of 10 to 80% by mass with respect to the resin. Is done.

<Adhesion auxiliary layer 18>
The adhesion auxiliary layer 18 plays a role of assisting adhesion between the insulating layer 16 and the adhesion resin layer 20 to be described later. When the adhesion between the insulation layer 16 and the adhesion resin layer 20 is good, the adhesion assistance layer 18 is used. Layer 18 may be omitted.
The adhesion assisting layer 18 gives an active species as a starting point of the binding reaction with the adhesion resin layer 20, and can generate many bonds between the adhesion assisting layer 18 and the adhesion resin layer 20 from the starting point. .
More specifically, as the adhesion auxiliary layer 18, a layer containing a polymerization initiator (polymerization initiation layer) or a layer having a functional group capable of initiating polymerization (polymerization initiation layer) can be used.

The thickness of the adhesion assisting layer 18 is not particularly limited, but is preferably 0.1 to 10 μm from the viewpoints of sufficient polymerization initiation ability and prevention of film peeling while maintaining film properties. 5 μm is more preferable. In mass after drying it is preferably 0.1 to 20 g / m ^2, more preferably ^{0.1~15g / m 2, 0.1~2g / m} 2 is more preferable.

Examples of the adhesion auxiliary layer 18 include a layer containing a polymer compound and a polymerization initiator, a layer containing a polymerizable compound and a polymerization initiator, a layer having a functional group capable of initiating polymerization, and polymerization can be initiated by applying energy. Examples include a layer that generates an active site and a layer that forms a chemical bond with the adhesive resin layer 20 by applying energy.
For example, the adhesion auxiliary layer 18 can be formed by dissolving necessary components in a solvent that can be dissolved, providing the components on the substrate surface by a method such as coating, and hardening by heating or light irradiation.

For example, when the insulating layer 16 formed on the wiring substrate 10 is made of a known insulating resin that has been used as a material for a multilayer laminate, a build-up substrate, or a flexible substrate, it is in close contact with the insulating layer 16. From the viewpoint of property, it is preferable to use an insulating resin composition similar to that used for forming the insulating layer 16 as the resin composition used when forming the adhesion assisting layer 18.
Hereinafter, the aspect of the close_contact | adherence auxiliary | assistant layer 18 formed from an insulating resin composition is demonstrated.

The insulating resin composition used when forming the adhesion assisting layer 18 may contain the same electrically insulating resin that constitutes the insulating layer 16 formed on the wiring substrate 10, and is different. However, it is preferable to use materials having similar thermal properties such as glass transition point, elastic modulus, and linear expansion coefficient. Specifically, for example, it is preferable in terms of adhesion to use the same type of insulating resin as the insulating resin constituting the insulating layer 16 formed on the wiring substrate 10.
In addition, inorganic or organic particles may be added in order to increase the strength of the adhesion auxiliary layer 18 and to improve electrical characteristics.

  Specific examples of the insulating resin may be, for example, a thermosetting resin, a thermoplastic resin, or a mixture thereof. Examples of the thermosetting resin include an epoxy resin, a phenol resin, a polyimide resin, a polyester resin, and a bismaleimide. Examples thereof include resins, polyolefin resins, isocyanate resins and the like.

  Examples of the thermoplastic resin include phenoxy resin, polyether sulfone, polysulfone, polyphenylene sulfone, polyphenylene sulfide, polyphenyl ether, polyether imide, and the like.

  Further, the adhesion auxiliary layer 18 may contain a compound having a polymerizable double bond, specifically an acrylate or methacrylate compound, in order to promote crosslinking within the layer, It is preferable to use one.

  The adhesion auxiliary layer 18 can be added with various compounds depending on the purpose as long as the effects of the present invention are not impaired. Specific examples include materials such as rubber and SBR latex that can relieve stress during heating, binders for improving film properties, plasticizers, surfactants, viscosity modifiers, and the like.

  Further, the adhesion auxiliary layer 18 may be filled with a filler (for example, inorganic filler such as silica, alumina, clay, talc, aluminum hydroxide, calcium carbonate, cured epoxy resin, crosslinked benzoguanamine resin, crosslinked acrylic polymer, etc., if necessary. Organic fillers), colorants, flame retardants, adhesion-imparting agents, silane coupling agents, antioxidants, ultraviolet absorbers and the like may be added singly or in combination.

  When adding these materials, it is preferable to add in the range of 0-200 mass% with respect to resin used as a main component, More preferably, it adds in the range of 0-80 mass%. When the adhesion auxiliary layer 18 and the material constituting the adjacent layer exhibit the same or similar physical property values with respect to heat and electricity, it is not always necessary to add these additives.

The adhesion auxiliary layer 18 preferably contains an active species (compound) that generates an active site capable of forming an interaction with the polymer compound constituting the adhesion resin layer 20. In order to generate this active site, some energy may be applied, and preferably, light (ultraviolet light, visible light, X-ray, etc.), plasma (oxygen, nitrogen, carbon dioxide, argon, etc.), heat, electricity, Etc. are used. Furthermore, active sites may be generated by chemically decomposing the surface with an oxidizing liquid (potassium permanganate solution) or the like.
Examples of the active species include polymerization initiators (for example, thermal polymerization initiators and photopolymerization initiators). Specifically, it is described in JP-A-2007-154306, paragraph numbers [0043] and [0044].
The amount of the polymerization initiator contained in the adhesion auxiliary layer 18 is preferably 0.1 to 50% by mass, and more preferably 1.0 to 30% by mass in terms of solid content.

(Formation method)
In the present invention, the adhesion assisting layer 18 can be formed by disposing a composition for forming an adhesion assisting layer on the insulating layer 16 by coating and removing the solvent to form a film. 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, so that the adhesion assisting layer 18 is formed after the adhesion resin layer 20 is formed on the adhesion assisting layer 18. This is preferable because the situation where the layer 18 is dropped can be effectively suppressed.
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 200 ° C. or less, the drying time is preferably within 60 minutes, It is more preferable to select heating conditions within a drying time of 20 minutes.

The solvent used when applying the components constituting the adhesion auxiliary layer 18 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 to 150 ° C. may be selected.
Specifically, cyclohexanone, methyl ethyl ketone, or the like can be used. In addition, the density | concentration of solid content in a coating solution has a preferable handling point of 2-50 mass%.

The adhesion assisting layer 18 can be formed by a known layer forming method such as a transfer method or a printing method in addition to the coating method.
When the transfer method is applied, a transfer laminate having a two-layer structure of the adhesion resin layer 20 and the adhesion auxiliary layer 18 may be manufactured and transferred onto the surface of the insulating layer 16 at once by the lamination method. .

<Adhesive resin layer 20>
The adhesion resin layer 20 is a layer obtained by using a polymer having a functional group and a polymerizable group that form an interaction with the plating catalyst or its precursor, and on the adhesion auxiliary layer 18 (when there is no adhesion auxiliary layer 18). Is provided on the insulating layer 16). The adhesion resin layer 20 adsorbs a later-described plating catalyst or a precursor thereof according to the function of a functional group that forms an interaction with the plating catalyst or the precursor in the polymer. That is, the adhesion resin layer 20 functions as a good receiving layer for the plating catalyst (or its precursor). Moreover, a polymeric group is utilized for the coupling | bonding between polymers, and the coupling | bonding with the close_contact | adherence auxiliary | assistant layer 18 (or insulating layer 16). As a result, excellent adhesion to the second conductive layer 24 (plating film) formed on the surface of the adhesion resin layer 20 is exhibited.
The thickness of the adhesive resin layer 20 is not particularly limited, but is preferably 0.1 to 5 μm and more preferably 0.2 to 2 μm from the viewpoint of handling properties and manufacturing cost.
Further, the surface roughness (Ra) of the adhesive resin layer 20 is preferably 0.01 to 0.3 μm, and more preferably 0.02 to 0.15 μm from the viewpoint of the wiring shape and the adhesive strength. In addition, the surface roughness (Ra) was measured using Surfcom 3000A (manufactured by Tokyo Seimitsu Co., Ltd.) based on Ra described in JIS B 0601 (Revision of 201010120) by non-contact interference method.

  The adhesion resin layer 20 includes a functional group and a polymerizable group, which are formed on the adhesion auxiliary layer 18 (or the insulating layer 16 when there is no adhesion auxiliary layer 18) and interact with the plating catalyst or its precursor. It is the layer which applied the energy to the layer containing the polymer which has, and was hardened. By applying energy to the layer containing the polymer, the reaction between the polymers proceeds via the polymerizable group, and the adhesion auxiliary layer 18 adjacent to the polymer (if there is no adhesion auxiliary layer 18, an insulating layer) It is possible to form a chemical bond directly with the surface of 16), and to form the adhesion resin layer 20 firmly bonded to the adhesion auxiliary layer 18 (or the insulating layer 16 when there is no adhesion auxiliary layer 18).

The method for forming the layer containing a polymer to which energy is applied is not particularly limited, and it is preferable to use a composition containing a polymer (hereinafter, referred to as a composition for forming an adhesive resin layer as appropriate).
Specifically, a method of immersing a substrate in the composition for forming an adhesive resin layer and a method of applying the composition for forming an adhesive resin layer on the insulating layer 16 (or the adhesion auxiliary layer 18) can be mentioned.
From the viewpoint of handleability and production efficiency, a mode in which a polymer-containing layer is formed by applying and drying the adhesive resin layer-forming composition on the insulating layer 16 (or the adhesion auxiliary layer 18) is preferable.
The aspect of the composition for forming an adhesive resin layer will be described in detail later.

When the composition for forming the adhesion resin layer is brought into contact with the insulating layer 16 (or the adhesion auxiliary layer 18), the coating amount is solid from the viewpoint of sufficient interaction with the plating catalyst or its precursor described later. preferably 0.1 to 10 g / m ² min terms, in particular 0.5 to 5 g / m ² is preferred.

(Energy application method)
As a method for applying energy for generating the adhesive resin layer 20, for example, radiation irradiation such as exposure can be used. For example, light irradiation with a UV lamp, visible light, or the like is possible. 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. Further, g-line, i-line, deep-UV light, and high-density energy beam (laser beam) are also used.
In addition, a heating method using a thermal recording head or the like, a scanning exposure method using an infrared laser, or the like, and a high-illuminance flash exposure such as a xenon discharge lamp or an infrared lamp exposure are also preferable methods.
The time required for energy application varies depending on the structure of the polymer used and the light source, but is usually between 10 seconds and 5 hours.

When energy is applied by exposure, the exposure power is in the range of 10 to 5000 mJ / cm ² in order to facilitate the graft polymerization and to suppress the decomposition of the produced graft polymer. Is more preferable, and the range of 50 to 3000 mJ / cm ² is more preferable.
In addition, when a polymer having an average molecular weight of 20,000 or more and a degree of polymerization of 200 or more is used as a polymer having a polymerizable group and an interactive group, graft polymerization proceeds easily with low energy exposure. Degradation of the polymer can be further suppressed.

  Below, the polymer used for formation of the adhesion resin layer 20 and the composition for adhesion resin layer formation are explained in full detail.

<Polymer>
The polymer used in the present invention has a functional group that interacts with the plating catalyst or its precursor (also referred to as an interactive group as appropriate) and a polymerizable group.

(Interactive group)
Examples of the interactive group include non-dissociable functional groups such as polar groups, groups capable of forming multidentate coordination, nitrogen-containing functional groups, sulfur-containing functional groups, and oxygen-containing functional groups (functions that do not generate protons by dissociation). Group).

The polar group may be a functional group having a positive charge such as ammonium or phosphonium, or an acid having a negative charge such as a sulfonic acid group, a carboxyl group, a phosphoric acid group, or a phosphonic acid group or capable of dissociating into a negative charge. Groups. These adsorb metal ions in the form of counterions of dissociating groups.
Further, for example, nonionic polar groups such as a hydroxyl group, an amide group, a sulfonamide group, an alkoxy group, and a cyano group can also be used.
In addition, imino groups, primary and secondary amino groups, amide groups, urethane groups, hydroxyl groups (including phenols), thiol groups, and the like can also be used.

Further, as the non-dissociable functional group, specifically, a group capable of forming a coordination with a metal ion, a nitrogen-containing functional group, a sulfur-containing functional group, an oxygen-containing functional group and the like are preferable. Specifically, imide group, pyridine group, tertiary amino group, ammonium group, pyrrolidone group, amidino group, group containing triazine ring structure, group containing isocyanuric structure, nitro group, nitroso group, azo group, diazo group A nitrogen-containing functional group such as azide group and cyanate group (R—O—CN), ether group, carbonyl group, ester group, group containing N-oxide structure, group containing S-oxide structure, N-hydroxy structure Oxygen-containing functional groups such as containing groups, thioether groups, thioxy groups, sulfoxide groups, sulfone groups, sulfite groups, groups containing sulfoximine structures, groups containing sulfoxynium salt structures, groups containing sulfonate ester structures, etc. Examples thereof include phosphorus-containing functional groups such as sulfur functional groups and phosphine groups, and groups containing halogen atoms such as chlorine and bromine. In addition, an imidazole group, a urea group, or a thiourea group may be used as long as it is non-dissociative due to a relationship with an adjacent atom or atomic group.
Among them, as the interactive group, a cyano group or a carboxylic acid group is particularly preferable because of its high polarity and high adsorption ability to a plating catalyst or the like. Moreover, it is preferable that both the cyano group and the carboxylic acid group are contained as an interactive group in the polymer from the viewpoint that the connection reliability and yield of the obtained multilayer wiring board are more excellent.

(Polymerizable group)
The polymerizable group is a functional group capable of forming a bond between polymers or between the polymer and the adhesion auxiliary layer 18 (or the insulating layer 16) by applying energy, for example, a radical polymerizable group, a cationic polymerizable group. Group and the like. Of these, a radical polymerizable group is preferable from the viewpoint of reactivity. Examples of the radical polymerizable group include unsaturated carboxylic acid ester groups such as acrylic acid ester groups, methacrylic acid ester groups, itaconic acid ester groups, crotonic acid ester groups, isocrotonic acid ester groups, maleic acid ester groups, styryl groups, Examples thereof include a vinyl group, an acrylamide group, and a methacrylamide group. Among these, a methacrylic acid ester group (methacryloyl group), an acrylic acid ester group (acryloyl group), a vinyl group, a styryl group, an acrylamide group, and a methacrylamide group are preferable, and an acryloyl group, a methacryloyl group, and a styryl group are particularly preferable.

  Examples of the polymer having a polymerizable group and an interactive group include homopolymers and copolymers obtained using a monomer having an interactive group, such as a vinyl group, an allyl group, and a (meth) acryl group. A polymer having an ethylene addition polymerizable unsaturated group (polymerizable group) introduced therein is preferable, and the polymer having a polymerizable group and an interactive group has a polymerizable group at least at the main chain terminal or side chain. And those having a polymerizable group in the side chain are preferred.

The method for synthesizing such a polymer having a polymerizable group and an interactive group is not particularly limited, and a known synthesis method (see paragraphs [0097] to [0125] of Patent Publication 2009-280905) is used.
For example, when it has a double bond group as a polymerizable group, it 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. Preference is given to methods ii) and iii) from the viewpoint of synthesis suitability.

Although the weight average molecular weight of a polymer is not specifically limited, 1000 or more and 700,000 or less are preferable, More preferably, it is 2000 or more and 200,000 or less. In particular, from the viewpoint of polymerization sensitivity, the weight average molecular weight is preferably 20000 or more.
Moreover, as a polymerization degree of a polymer, it is preferable to use a 10-mer or more thing, More preferably, it is a 20-mer or more thing. Moreover, 7000-mer or less is preferable, 3000-mer or less is more preferable, 2000-mer or less is still more preferable, 1000-mer or less is especially preferable.

(Preferred embodiment)
As a preferred embodiment of the polymer, a polymer having a unit (unit having a polymerizable group) represented by the following formula (1) can be mentioned. When the unit is contained in the polymer, excellent adhesion to the adhesion auxiliary layer 18 or the resin layer 16 is expressed, and a film having excellent strength can be obtained by a crosslinking reaction in the film.

In formula (1), R < ¹ > -R < ⁴ > represents a hydrogen atom or a substituted or unsubstituted alkyl group each independently.
When R < ¹ > -R < ⁴ > is a substituted or unsubstituted alkyl group, a C1-C6 alkyl group is preferable and a C1-C4 alkyl group is more preferable. More specifically, examples of the unsubstituted alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group, and examples of the substituted alkyl group include a methoxy group, a hydroxy group, and a halogen atom (for example, a chlorine atom). , A bromine atom, a fluorine atom) and the like, and a methyl group, an ethyl group, a propyl group, and a butyl group.

R ¹ is preferably a hydrogen atom, a methyl group, or a methyl group substituted with a hydroxy group or a bromine atom.
R ² is preferably a hydrogen atom, a methyl group, or a methyl group substituted with a hydroxy group or a bromine atom.
R ³ is preferably a hydrogen atom.
R ⁴ is preferably a hydrogen atom.

  Y and Z each independently represent a single bond or a substituted or unsubstituted divalent organic group. Examples of the divalent organic group include a substituted or unsubstituted aliphatic hydrocarbon group (preferably having 1 to 3 carbon atoms), a substituted or unsubstituted aromatic hydrocarbon group (preferably having 6 to 12 carbon atoms), -O —, —S—, —N (R) — (R: alkyl group), —CO—, —NH—, —COO—, —CONH—, or a combination thereof (eg, alkyleneoxy group, alkyleneoxy group) Carbonyl group, alkylenecarbonyloxy group, etc.). The organic group may have a substituent such as a hydroxy group as long as the effects of the invention are not impaired.

Examples of the substituted or unsubstituted aliphatic hydrocarbon group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, or a methoxy group, a hydroxy group, a halogen atom (for example, a chlorine atom). , Bromine atom, fluorine atom) and the like.
The substituted or unsubstituted aromatic hydrocarbon group is preferably an unsubstituted phenylene group or a phenylene group substituted with a methoxy group, a hydroxy group, a halogen atom (for example, a chlorine atom, a bromine atom, or a fluorine atom). .
Among them, — (CH ₂ ) _n — (n is an integer of 1 to 3) is preferable, and —CH ₂ — is more preferable.

  Y and Z are preferably an ester group (—COO—), an amide group (—CONH—), an ether group (—O—), or a substituted or unsubstituted aromatic hydrocarbon group.

L ¹ represents a substituted or unsubstituted divalent organic group. The definition of a divalent organic group is synonymous with the organic group represented by said Y and Z, for example, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, -O —, —S—, —N (R) — (R: alkyl group), —CO—, —NH—, —COO—, —CONH—, or a combination thereof.

L ¹ is preferably an unsubstituted alkylene group or a divalent organic group having a urethane bond or urea bond, more preferably an unsubstituted alkylene group or a divalent organic group having a urethane bond, and the total number of carbon atoms. Those having 1 to 9 are particularly preferred. Incidentally, the total number of carbon atoms of L ^1, means the total number of carbon atoms contained in the substituted or unsubstituted divalent organic group represented by L ^1.
More specifically, the structure of L ¹ is preferably a structure represented by Formula (1-1) or Formula (1-2).

In formula (1-1) and formula (1-2), R ^a and R ^b each independently represent a divalent organic group. The definition of the divalent organic group is the same as described above. Preferably, a substituted or unsubstituted alkylene group such as a methylene group, an ethylene group, a propylene group, or a butylene group, or an ethylene oxide group, a diethylene oxide group, Examples thereof include polyoxyalkylene groups such as ethylene oxide group, tetraethylene oxide group, dipropylene oxide group, tripropylene oxide group and tetrapropylene oxide group.

  A preferred embodiment of the unit represented by the formula (1) includes a unit represented by the formula (1-A).

In the formula (1-A), R ¹ , R ² , X and L ¹ are the same as the definitions of each group in the unit represented by the formula (1). T represents an oxygen atom or NR (R represents a hydrogen atom or an alkyl group, preferably a hydrogen atom or an unsubstituted alkyl group having 1 to 5 carbon atoms).

  A preferred embodiment of the unit represented by the formula (1-A) is a unit represented by the formula (1-B).

In formula (1-B), R ¹ , R ² , and L ¹ are the same as defined for each group in the unit represented by formula (1-A). V and T represent an oxygen atom or NR (R represents a hydrogen atom or an alkyl group, preferably a hydrogen atom or an unsubstituted alkyl group having 1 to 5 carbon atoms).

In the above formula (1-B), T is preferably an oxygen atom.
In the above formulas (1-A) and (1-B), L ¹ is preferably an unsubstituted alkylene group or a divalent organic group having a urethane bond or a urea bond. A valent organic group is more preferable, and a group having 1 to 9 carbon atoms is particularly preferable.

  Although the content of the unit represented by the formula (1) in the polymer is not particularly limited, it is based on the total unit (100 mol%) in terms of reactivity (polymerizability, curability) and adhesion to the substrate. 5 to 50 mol% is preferable, and 5 to 40 mol% is more preferable. When the amount is less than 5 mol%, the reactivity (curability and polymerizability) may be reduced. When the amount exceeds 50 mol%, gelation is likely to occur during the synthesis of the polymer, and the control of the reaction becomes difficult.

  As a preferred embodiment of the polymer, a polymer having a unit (unit having an interactive group) represented by the following formula (2) can be mentioned. By including the unit in the polymer, the adsorptivity to the plating catalyst or its precursor described later is improved, and excellent adhesion between the adhesive resin layer 20 and the second conductive film 24 described later is ensured. .

In formula (2), R ⁵ represents a hydrogen atom or a substituted or unsubstituted alkyl group. The substituted or unsubstituted alkyl group represented by R ⁵ has the same meaning as the substituted or unsubstituted alkyl group represented by R ^{1 to} R ⁴ described above.
R ⁵ is preferably a hydrogen atom, a methyl group, or a methyl group substituted with a hydroxy group or a bromine atom.

X and L ² each independently represents a single bond or a substituted or unsubstituted divalent organic group. The definition of the divalent organic group is synonymous with the divalent organic group represented by Z and Y, for example, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group. , -O-, -S-, -N (R)-(R: alkyl group), -CO-, -NH-, -COO-, -CONH-, or a combination thereof.

  X preferably includes a single bond, an ester group (—COO—), an amide group (—CONH—), an ether group (—O—), or a substituted or unsubstituted aromatic hydrocarbon group, and more preferably. Are a single bond, an ester group (—COO—), and an amide group (—CONH—).

L ² is preferably a linear, branched, or cyclic alkylene group, an aromatic group, or a group obtained by combining these. The group obtained by combining the alkylene group and the aromatic group may further be via an ether group, an ester group, an amide group, a urethane group, or a urea group.
Among these, L ² preferably has 1 to 15 total carbon atoms, and particularly preferably unsubstituted. Incidentally, the total number of carbon atoms of L ^2, means the total number of carbon atoms contained in the substituted or unsubstituted divalent organic group represented by L ^2.
Specifically, a methylene group, an ethylene group, a propylene group, a butylene group, a phenylene group, and those groups substituted with a methoxy group, a hydroxy group, a chlorine atom, a bromine atom, a fluorine atom, etc., The group which combined these is mentioned.

  W represents a functional group (interactive group) that forms an interaction with the plating catalyst or a precursor thereof, and the definition thereof is as described above. Of these, a cyano group or a carboxylic acid group is preferable because it is excellent in adsorptivity to the plating catalyst or its precursor.

  In the polymer, the unit represented by the formula (2) of two or more different types of W may be included, and the connection reliability and yield of the obtained multilayer wiring board are more excellent. It is preferable that a unit represented by the formula (2) in which W is a cyano group and a unit represented by the formula (2) in which W is a carboxylic acid group are included.

  A preferred embodiment of the unit represented by the formula (2) is a unit represented by the formula (2-A).

In said formula (2-A), R < ⁵ >, L < ² > and W are the same as the definition of each group in the unit represented by Formula (2). U represents an oxygen atom or NR ′ (R ′ represents a hydrogen atom or an alkyl group, preferably a hydrogen atom or an unsubstituted alkyl group having 1 to 5 carbon atoms).

L ² in the formula (2-A) is a linear, branched, or cyclic alkylene group, an aromatic group (in particular, a divalent aromatic hydrocarbon group is preferable), or a combination thereof. Is preferred.
In particular, in the formula (2-A), the connecting site with W in L ² is preferably a divalent organic group having a linear, branched, or cyclic alkylene group. These organic groups preferably have 1 to 10 carbon atoms in total.
As another preferred embodiment, the connecting portion of the W in L ² in Formula (2-A) is preferably a divalent organic group having an aromatic group, and among them, the divalent organic The group preferably has a total carbon number of 6 to 15.

  The content of the unit represented by the formula (2) in the polymer is not particularly limited, but is preferably 5 to 95 mol% with respect to all units (100 mol%) in terms of adsorptivity to the plating catalyst and the like. 10-95 mol% is more preferable.

  The bonding mode of the above units in the polymer (unit represented by formula (1), unit represented by formula (2)) is not particularly limited, and even if each unit is a random polymer bonded at random, A block polymer in which each unit is connected to the same type to form a block portion may be used.

  The polymer may contain other units in addition to the unit represented by the above formula (1) and the unit represented by the formula (2).

(Adhesive resin layer forming composition)
The above polymer is contained in the composition for forming an adhesive resin layer.
The content of the polymer in the composition for forming an adhesive resin layer is not particularly limited, but is preferably 2 to 50% by mass and more preferably 5 to 30% by mass with respect to the total amount of the composition. If it is in the said range, it is excellent in the handleability of a composition and it is easy to control the layer thickness of the contact | adherence resin layer 20. FIG.

The composition for forming an adhesive resin layer may contain a solvent as necessary in addition to the polymer.
Examples of solvents 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, methyl ethyl ketone, and cyclohexanone, formamide, dimethylacetamide, Amide solvents such as N-methylpyrrolidone, nitrile solvents such as acetonitrile and propyronitrile, ester solvents such as methyl acetate and ethyl acetate, carbonate solvents such as dimethyl carbonate and diethyl carbonate, and other ether solvents A solvent, a glycol solvent, an amine solvent, a thiol solvent, a halogen solvent, etc. are mentioned.
Among these, amide solvents, ketone solvents, nitrile solvents, and carbonate solvents are preferable, and specifically, acetone, dimethylacetamide, methyl ethyl ketone, cyclohexanone, acetonitrile, propionitrile, N-methylpyrrolidone, and dimethyl carbonate are preferable. .

  Although content in particular of the solvent in the composition for adhesion resin layer formation is not restrict | limited, 50-98 mass% is preferable with respect to the composition whole quantity, and 70-95 mass% is more preferable. If it is in the said range, it is excellent in the handleability of a composition and control of the layer thickness of the contact | adherence resin layer 20 is easy.

  The adhesive resin layer forming composition further includes a surfactant, a plasticizer, a polymerization inhibitor, a curing agent, a radical generator, a sensitizer, a rubber component (for example, CTBN), a flame retardant (for example, , Phosphorus flame retardants), diluents and thixotropic agents, pigments, antifoaming agents, leveling agents, coupling agents and the like may be added.

Through the above process, a laminate 22 is obtained in which the insulating layer 16, the adhesion auxiliary layer 18 and the adhesion resin layer 20 that are formed as desired are formed on the surface of the wiring substrate 10 [see FIG. 1A].
The adhesion resin layer 20 is useful as a plating metal receiving layer. Therefore, the laminate 22 in the present invention is useful for forming the second conductive film 24 (second wiring) with good adhesion on the wiring substrate 10. In FIG. 1A, the insulating layer 16, the adhesion auxiliary layer 18, and the adhesion resin layer 20 are provided on both surfaces of the wiring substrate 10, but may be provided only on one surface.

<Process (B): Plating process>
In the step (B), a plating catalyst or a precursor thereof is applied to the adhesion resin layer after the step (A), and then plating is performed to form a second conductive layer on the adhesion resin layer.
More specifically, as shown in FIG. 1B, the second conductive layer 24 is formed on the adhesion resin layer 20.
Although the metal which comprises the 2nd conductive layer 24 can be suitably selected according to the kind of plating mentioned later, copper, silver, tin, palladium, gold | metal | money, nickel, chromium, tungsten, indium, zinc, or gallium etc. Preferably mentioned.

In this step, the interactive group contained in the adhesive resin layer 20 adheres (adsorbs) the applied plating catalyst or its precursor depending on its function. More specifically, a plating catalyst or a precursor thereof is attached in the adhesive resin layer 20 or on the surface thereof.
Examples of the plating catalyst or its precursor include those that function as a plating catalyst or an electrode in the plating treatment described later. Therefore, the type of the plating catalyst or its precursor is appropriately determined depending on the type of plating.
In addition, it is preferable that the plating catalyst used in this process or its precursor is an electroless plating catalyst or its precursor.
Hereinafter, electroless plating or a precursor thereof will be described in detail.

(Electroless plating catalyst)
Any electroless plating catalyst can be used as long as it becomes an active nucleus at the time of electroless plating. Specifically, a metal having a catalytic ability for an autocatalytic reduction reaction (lower ionization tendency than Ni). And the like, specifically, Pd, Ag, Cu, Ni, Al, Fe, Co, and the like. Among them, those capable of multidentate coordination are preferred, and Ag and Pd are particularly preferred from the number of types of functional groups capable of coordination and high catalytic ability.
A metal colloid may be used as the electroless plating catalyst. In general, a metal colloid can be prepared by reducing metal ions in a solution containing a charged surfactant or a charged protective agent. The charge of the metal colloid can be adjusted by the surfactant or protective agent used here.

(Electroless plating catalyst precursor)
The electroless plating catalyst precursor can be used without particular limitation as long as it can become an electroless plating catalyst by a chemical reaction. The metal ions of the metals mentioned as the electroless plating catalyst are mainly used. The metal ion that is an electroless plating catalyst precursor becomes a zero-valent metal that is an electroless plating catalyst by a reduction reaction. The metal ion which is the electroless plating catalyst precursor may be applied to the adhesion resin layer 20 and then converted into a zero-valent metal by a reduction reaction before immersion in the electroless plating bath, and may be used as an electroless plating catalyst. Alternatively, the electroless plating catalyst precursor may be immersed in an electroless plating bath and changed to a metal (electroless plating catalyst) by a reducing agent in the electroless plating bath.

The metal ion that is the electroless plating precursor is preferably applied to the adhesion resin layer 20 using a metal salt. The metal salt used is not particularly limited as long as it is dissolved in a suitable solvent and dissociated into a metal ion and a base (anion), and M (NO ₃ ) _n , MCl _n , M _{2 / n} (SO ₄ ), M _{3 / n} (PO ₄ ) Pd (OAc) _n (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. Specific examples include, for example, Ag ions, Cu ions, Al ions, Ni ions, Co ions, Fe ions, and Pd ions. Among them, those capable of multidentate coordination are preferable, and in particular, functionalities capable of coordination. In view of the number of types of groups and catalytic ability, Ag ions and Pd ions are preferable.

  One of preferred examples of the electroless plating catalyst or precursor thereof used in the present invention is a palladium compound. This palladium compound acts as a plating catalyst (palladium) or a precursor thereof (palladium ions), which acts as an active nucleus during the plating treatment and plays a role of depositing metal. The palladium compound is not particularly limited as long as it contains palladium and acts as a nucleus in the plating process, and examples thereof include a palladium (II) salt, a palladium (0) complex, and a palladium colloid.

Examples of the palladium salt include palladium acetate, palladium chloride, palladium nitrate, palladium bromide, palladium carbonate, palladium sulfate, bis (benzonitrile) dichloropalladium (II), bis (acetonitrile) dichloropalladium (II), and bis (ethylenediamine). ) Palladium (II) chloride and the like. Of these, palladium nitrate, palladium acetate, palladium sulfate, and bis (acetonitrile) dichloropalladium (II) are preferable in terms of ease of handling and solubility.
Examples of the palladium complex include tetrakistriphenylphosphine palladium complex and dipalladium trisbenzylideneacetone complex.
The palladium colloid is a particle composed of palladium (0), and its size is not particularly limited, but is preferably 5 nm to 300 nm, more preferably 10 nm to 100 nm, from the viewpoint of stability in the liquid. The palladium colloid may contain other metals as necessary, and examples of the other metals include tin. Examples of the palladium colloid include tin-palladium colloid. The palladium colloid may be synthesized by a known method or a commercially available product may be used. For example, a palladium colloid can be prepared by reducing palladium ions in a solution containing a charged surfactant or a charged protective agent.

(Other catalysts)
In this step, a zero-valent metal can be used as a catalyst used for direct electroplating without electroless plating. Examples of the zero-valent metal include Pd, Ag, Cu, Ni, Al, Fe, and Co. Among them, those capable of multidentate coordination are preferable, and in particular, adsorptive (adhesive) property to an interactive group, Pd, Ag, and Cu are preferable because of their high catalytic ability.

As a method for applying a metal that is an electroless plating catalyst or a metal salt that is an electroless plating precursor to the adhesion resin layer 20, a dispersion in which a metal is dispersed in an appropriate dispersion medium or a metal salt is appropriately used. A solution containing dissolved and dissociated metal ions is prepared, and the dispersion or solution is applied onto the adhesion resin layer 20, or the adhesion resin layer 20 is formed in the dispersion or solution. What is necessary is just to immerse a body.
Further, in the step (A), a composition for forming an adhesive resin layer containing a polymer having a polymerizable group and an interactive group may be brought into contact with the adhesion auxiliary layer 18. You may use the method of adding an electroplating catalyst or its precursor.
A composition containing a polymerizable group and an interactive group and a composition containing an electroless plating catalyst or a precursor thereof are brought into contact with the adhesion auxiliary layer 18 and applied with a surface graft polymerization method. It is possible to form the adhesion resin layer 20 having a functional group and containing a polymer directly chemically bonded to the adhesion auxiliary layer 18 and a plating catalyst or a precursor thereof.

(Organic solvent and water)
The plating catalyst or precursor as described above can be applied to the adhesion resin layer 20 as a dispersion or solution (catalyst solution). An organic solvent or water is used for the catalyst solution.
By containing the organic solvent, the permeability of the plating catalyst or precursor to the adhesive resin layer 20 is improved, and the plating catalyst or its precursor can be efficiently adsorbed to the interactive group.

  Water may be used for the catalyst solution, and it is preferable that this water does not contain impurities. From such a viewpoint, it is preferable to use RO water, deionized water, distilled water, purified water, or the like. It is particularly preferable to use deionized water or distilled water.

  The organic solvent used for the preparation of the catalyst solution is not particularly limited as long as it is a solvent that can penetrate into the adhesive resin layer 20, and specifically, acetone, methyl acetoacetate, ethyl acetoacetate, ethylene glycol diacetate, Cyclohexanone, acetylacetone, acetophenone, 2- (1-cyclohexenyl), propylene glycol diacetate, triacetin, diethylene glycol diacetate, dioxane, N-methylpyrrolidone, dimethyl carbonate, dimethyl cellosolve, and the like can be used.

  In particular, a water-soluble organic solvent is preferable from the viewpoint of compatibility with the plating catalyst or its precursor and permeability to the adhesive resin layer 20, and acetone, dimethyl carbonate, dimethyl cellosolve, triethylene glycol monomethyl ether, diethylene glycol dimethyl ether, Diethylene glycol diethyl ether is preferred.

The content of the solvent (water, organic solvent) is preferably 0.5 to 40% by mass, more preferably 5 to 30% by mass, and particularly preferably 5 to 20% by mass with respect to the total amount of the catalyst solution.
In addition to the plating catalyst or its precursor and water as the main solvent, the plating catalyst solution may contain other additives depending on the purpose within a range not impairing the effects of the present invention. Examples of the additive include those shown below.
Examples include swelling agents (such as organic compounds such as ketones, aldehydes, ethers, esters, etc.) and surfactants (such as anionic, cationic, zwitterionic, nonionic, low molecular or polymeric). .

By contacting the plating catalyst or a precursor thereof as described above, the interaction group in the adhesion resin layer 20 interacts with an intermolecular force such as van der Waals force or is coordinated with a lone electron pair. The plating catalyst or its precursor can be adsorbed by utilizing the interaction by bonding.
From the viewpoint of sufficiently performing such adsorption, the metal concentration in the dispersion, solution, composition, or metal ion concentration in the solution is preferably in the range of 0.001 to 50% by mass, More preferably, it is in the range of 0.005 to 30% by mass. Further, the contact time is preferably about 30 seconds to 24 hours, more preferably about 1 minute to 1 hour.
In the previous stage of this step (B), an interaction can be formed between the interactive group in the adhesive resin layer 20 and the plating catalyst or its precursor.

(Plating treatment)
Then, the 2nd conductive layer (plating film) 24 is formed in the surface of the adhesion resin layer 20 by plating with respect to the adhesion resin layer 20 to which the electroless-plating catalyst or its precursor was provided. 1 (B)]. The formed second conductive layer 24 functions as a second metal wiring and has excellent conductivity and adhesion.
The thickness of the second conductive layer is not particularly limited, but is preferably 0.2 to 20 μm, more preferably 0.4 to 10 μm, from the viewpoint of ease of laser drilling and via connection reliability. 5-10 micrometers is especially preferable.

The type of plating performed in this step includes electroless plating and electroplating, and can be appropriately selected depending on the function of the plating catalyst or its precursor. Especially, it is preferable to perform electroless plating from the point of the formation of the hybrid structure expressed in the adhesive resin layer 20 and the improvement of adhesiveness. In order to obtain a plating layer having a desired film thickness, it is a more preferable aspect that electroplating is further performed after electroless plating.
Hereinafter, the plating suitably performed in this process will be described.

(Electroless plating)
Electroless plating refers to an operation of depositing a metal by a chemical reaction using a solution in which metal ions to be deposited as a plating are dissolved.
The electroless plating in this step is performed, for example, by immersing the laminate provided with the electroless plating catalyst in water to remove excess electroless plating catalyst (metal) and then immersing it in an electroless plating bath. As the electroless plating bath to be used, a generally known electroless plating bath can be used.

In addition, when the laminate to which the electroless plating catalyst precursor is applied is immersed in an electroless plating bath in a state where the electroless plating catalyst precursor is adsorbed or impregnated in the adhesion resin layer 20, the laminate is washed with water. It is preferable to immerse in an electroless plating bath after removing excess precursors (such as metal salts). In this case, reduction of the plating catalyst precursor and subsequent electroless plating are performed in the electroless plating bath. As the electroless plating bath used here, a generally known electroless plating bath can be used as described above.
In addition, the reduction of the electroless plating catalyst precursor may be performed as a separate step before electroless plating by preparing a catalyst activation liquid (reducing liquid) separately from the embodiment using the electroless plating liquid as described above. Is possible. The catalyst activation liquid is a liquid in which a reducing agent capable of reducing an electroless plating catalyst precursor (mainly metal ions) to zero-valent metal is dissolved, and its concentration is preferably 0.1 to 50% by mass, and 1 to 30% by mass. % Is more preferable. As the reducing agent, it is possible to use a boron-based reducing agent such as sodium borohydride or dimethylamine borane, or a reducing agent such as formaldehyde or hypophosphorous acid.

  As a composition of a general electroless plating bath, in addition to a solvent, 1. metal ions for plating; 2. reducing agent; Additives (stabilizers) that improve the stability of metal ions are mainly included. In addition to these, the plating bath may contain known additives such as a plating bath stabilizer.

  Examples of the solvent used for the electroless plating bath include water and organic solvents. As the organic solvent, it is necessary to be a solvent that can be used for water, and from this point, ketones such as acetone and alcohols such as methanol, ethanol, and isopropanol are preferably used.

Copper, tin, lead, nickel, gold, palladium, and rhodium are known as the types of metals used in the electroless plating bath, and copper and gold are particularly preferable from the viewpoint of conductivity.
Moreover, the optimal reducing agent and additive are suitably selected according to the said metal. For example, a copper electroless plating bath contains CuSO ₄ as a copper salt, HCOH as a reducing agent, a chelating agent such as EDTA or Rochelle salt, which is a stabilizer for copper ions, and a trialkanolamine. . 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. The palladium electroless plating bath 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.

  The immersion time in the plating bath is preferably about 1 minute to 6 hours, and more preferably about 1 minute to 3 hours.

(Electroplating)
In this step, when the plating catalyst or precursor thereof applied in step (B) has a function as an electrode, electroplating is performed on the adhesive resin layer 20 to which the catalyst or precursor thereof is applied. It can be carried out. In addition, after the above-described electroless plating, the formed plating film may be used as an electrode, and electroplating may be further performed. As a result, the second conductive layer 24 (metal layer) having an arbitrary thickness can be easily formed on the electroless plating film having excellent adhesion to the substrate. Thus, by performing electroplating after electroless plating, the second conductive layer 24 (metal layer) can be formed to a thickness according to the purpose.

  As a method of electroplating, a conventionally known method can be used. Examples of the metal used for electroplating 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. preferable.

  The thickness of the metal layer obtained by electroplating varies depending on the application, and can be controlled by adjusting the concentration of metal contained in the plating bath or the current density.

In the present invention, the metal deposited in the adhesive resin layer 20 by the plating process (electroless plating or electroplating) is formed as a fractal microstructure in the layer, whereby the second conductive The adhesion between the layer 24 and the adhesion resin layer 20 can be further improved.
The amount of metal present in the adhesive resin layer 20 is such that when the cross section of the substrate is photographed with a metal microscope, the proportion of metal in the region from the outermost surface of the adhesive resin layer 20 to a depth of 0.5 μm is 5 to 50 areas. %, And when the arithmetic average roughness Ra (JIS B0633-2001) between the adhesive resin layer 20 and the metal interface is 0.05 μm to 0.5 μm, a stronger adhesive force is expressed.

<Process (C): Via hole formation process>
In step (C), after step (B), the second conductive layer, the adhesive resin layer, and the insulating layer are removed and penetrated by laser processing or drilling, and a via hole is formed so as to reach the first conductive layer. To do. In addition, when there exists a close_contact | adherence auxiliary | assistant layer, this close_contact | adherence auxiliary | assistant layer is also removed and penetrated by the said process.
More specifically, as shown in FIG. 1C, in this step, the first conductive layer penetrates through the second conductive layer 24, the adhesion resin layer 20, the adhesion auxiliary layer 18, and the insulating layer 16. A via hole 26 is formed in order to connect the first conductive layer 14 to the second conductive layer 24.

As a method for forming the via, laser processing or drilling may be mentioned.
The laser used for the laser processing is not particularly limited as long as the second conductive layer 24, the adhesion resin layer 20, the adhesion auxiliary layer 18 and the insulating layer 16 can be removed and a via hole having a desired diameter can be formed. There is no limit. Among these, carbon dioxide laser (CO ₂ laser), UV-YAG laser, excimer laser, etc. are used because of excellent workability, that is, each layer can be ablated efficiently and productivity is excellent. It is done. Among these, a UV-YAG laser is preferable in that a micro via having a size of less than 60 μm is formed.

  The drilling is not particularly limited as long as the second conductive layer 24, the adhesion resin layer 20, the adhesion auxiliary layer 18 and the insulating layer 16 can be removed and a via hole having a desired diameter can be formed. From the viewpoint of the workability and small diameter via workability, the spin drill method is generally used.

  The diameter of the via hole 26 formed in this step is appropriately selected according to the purpose of use, but the top diameter (φ) is 20 to 150 μm from the viewpoint of forming a high-density multilayer substrate. The bottom diameter (φ) is preferably 20 to 120 μm, the top diameter (φ) is 20 to 60 μm, and the bottom diameter (φ) is 20 to 50 μm from the viewpoint of wiring miniaturization and integration. Then, it is more preferable.

<Process (D): Desmear treatment>
In the step (D), a desmear process for removing smear (residue) remaining in the via hole 26 formed in the step (C) is performed.
When the second conductive layer 24, the adhesion resin layer 20, the adhesion auxiliary layer 18 and the insulating layer 16 are partially removed by laser machining or drilling, a melt or decomposition product when the resin melts or decomposes The insulating layer 16 is attached to the bottom of the via hole by adjusting the laser processing so that it adheres to the side surface and bottom of the via hole 26 and does not directly affect the first conductive layer 14 present at the bottom of the via hole 26. Some may remain. In this step, such a residue is removed.

The desmear treatment method is not particularly limited, and a known method is adopted. However, the surface of the via hole 26 is roughened by a dry method and / or a wet method.
Examples of the dry roughening method include mechanical polishing such as buffing and sandblasting, and plasma etching.
On the other hand, wet roughening methods include chemical methods such as a method using an oxidizing agent such as permanganate, dichromate, ozone, hydrogen peroxide / sulfuric acid, nitric acid, or a method using a strong base or a resin swelling solvent. Examples include chemical treatment. From the simplicity of the process, chemical treatment using permanganate or the like is preferable.

  As a specific method of desmear treatment, for example, MLB211 (available from Rohm and Haas Electronic Materials Co., Ltd.), which is a commercial product, is added to a swelling bath containing 20% by volume and 10% by volume of Quposit Z at 1 to 60-85 ° C. After dipping for 15 minutes, the etching bath containing 10% by volume of MLB213A (Rohm and Haas Electronic Materials Co., Ltd.) and 15% by volume of MLB213B (Rohm and Haas Electronic Materials Co., Ltd.) at 2 to 15 at 55 to 85 ° C. For example, a known method may be used, such as a dipping treatment for 30 minutes and dipping in a neutralization bath containing 20% by volume of MLB 216-2 (Rohm and Haas Electronic Materials Co., Ltd.) at 35 ° C. to 55 ° C. for 2 to 10 minutes.

  As another method of desmear treatment, there is a treatment having an etching step at 80 ° C. for 10 minutes using a sodium permanganate etching solution, a neutralization step at 40 ° C. for 5 minutes using a sulfuric acid-based neutralizing solution, and the like. Can be mentioned.

  Even if the desmear treatment is performed, the surface of the first conductive layer 14 and the second conductive layer 24 is maintained without being affected by chemicals, but the exposed portion of the side surface of the via hole 26 is smeared. The surface is also roughened with the removal. Therefore, the affinity and adhesion between the conductive metal film 28 that conducts the first conductive layer 14 and the second conductive layer 24 and the wall surface of the via hole 26, which are formed in the step (E) described later, are improved. It will also have the advantage.

<Process (E): Conduction process>
In the step (E), after the step (D), after applying graphite or carbon black to the via hole wall surface, electroplating is performed without performing electroless plating, and the first conductive layer and the second conductive layer are formed. The conductive layer is electrically connected.
More specifically, as shown in FIG. 1D, in this step, electroplating treatment after applying graphite or carbon black between the first conductive layer 14 and the second conductive layer 26 is performed. The conductive metal film 28 formed by the above is formed. As shown in FIG. 1D, the conductive metal film 28 may be formed not only on the side surface of the via hole 26 but also on the surfaces of the first conductive layer 14 and the second conductive layer 26.

(Graphite or carbon black)
In this step, graphite and / or carbon black (hereinafter also referred to as a carbon catalyst) is used from the viewpoint of improving via filling, and graphite is particularly preferable.

The type of graphite is not particularly limited, and for example, scaly graphite, artificial graphite, earthy graphite and the like are used.
The average particle diameter of graphite is not particularly limited, but is preferably 0.05 to 8 μm from the viewpoint of improving the via filling.
The BET specific surface area of graphite is not particularly limited, but is preferably 1 to 100 m ² / g in that the connection reliability of the resulting multilayer wiring board is higher.

The type of carbon black is not particularly limited, and conventionally known carbon black such as SAF, ISAF, HAF, and FEF can be used.
The average particle size of the carbon black is not particularly limited, but is preferably 0.01 to 1 μm from the viewpoint of improving the via filling.
The BET specific surface area of graphite is not particularly limited, but is preferably 1 to 100 m ² / g from the viewpoint of improving via filling.

(Catalyst application method)
The method for applying the carbon catalyst to the wall surface of the via hole 26 is not particularly limited. However, from the viewpoint of excellent operability and easy control of the amount of catalyst on the wall surface, a solution or dispersion containing the carbon catalyst is added to the via hole 26. A method of contacting the wall surface is preferred. A method for bringing the solution or dispersion into contact with the wall surface of the via hole 26 is not particularly limited. For example, a method of applying the solution or dispersion on a laminate having the via hole 26 or a via hole 26 in the solution or dispersion is used. The method of immersing the laminated body which has this is mentioned.
In addition, when implementing the immersion method, it is preferable to immerse a laminated body in this solution or a dispersion for 3 to 10 minutes from points, such as productivity.

The solvent used in the solution or dispersion is not particularly limited, and examples thereof include a solvent contained in the above-described composition for forming an adhesive resin layer.
Of these, water, ethanol, diol (glycol) and the like are preferable from the viewpoint of excellent catalyst application and cleaning efficiency.
The content of the carbon catalyst in the solution or dispersion is appropriately selected according to the type of solvent and catalyst used, but the total amount of the solution or dispersion is excellent in terms of catalyst application efficiency. The content is preferably 0.1 to 5% by mass, and more preferably 0.2 to 3% by mass.

After applying the catalyst, if necessary, a cleaning step may be provided in order to remove excess carbon catalyst attached on the first conductive layer 14 and the second conductive layer 24.
Specifically, a method of removing excess carbon catalyst by bringing the cleaning liquid into contact with the first conductive layer 14 and the second conductive layer 24 can be mentioned. The method of bringing the cleaning liquid into contact is not particularly limited, and a method of applying the cleaning liquid onto the first conductive layer 14 and the second conductive layer 24, or a laminate including the first conductive layer 14 and the second conductive layer 24. The method of immersing in a washing | cleaning liquid is mentioned.
Examples of the cleaning liquid include sulfuric acid / hydrogen peroxide aqueous solution.

(Plating method)
Without applying electroless plating after applying a carbon catalyst to the wall surface of the via hole 26 (specifically, as shown in FIG. 1C, the insulating layer 16, the adhesion auxiliary layer 18, and the adhesion resin layer 20). Electroplating is performed. When electroless plating is performed, the connection between the first conductive layer 14 and the second conductive layer 24 becomes insufficient, and connection reliability is impaired. Furthermore, the problem that the adhesiveness of the plating film formed on the 2nd conductive layer 24 is not enough arises.

As the electroplating method in this step, the same method as the electroplating described in the above step (B) can be performed.
In addition, before performing electroplating, the process (F) and (G) mentioned later may be performed, a pattern-form resist layer may be formed on the contact | adherence resin layer 20, and electroplating may be performed after that. In this case, the resist layer may be removed by performing step (I) described later after electroplating.

  Although the thickness of the conductive metal film 28 that conducts the first conductive layer 14 and the second conductive layer 24 can be appropriately controlled, it is preferably 4 to 50 μm from the viewpoint of circuit design such as impedance control. More preferably, it is ˜30 μm.

The multilayer wiring board having two layers of wiring obtained by the above process can also be used as a board serving as a core for forming further wiring so as to be suitable for mounting. As a method of laminating further wiring on the multilayer wiring board obtained by the forming method of the present invention, a known semi-additive method, subtractive method, or the like can be applied.
Hereinafter, a typical forming method for forming further wiring using the multilayer wiring board obtained by the forming method of the present invention will be described. In order to further form wiring on the surface of the second conductive layer 24, the following steps (F) to (I) can be performed.

<Step (F): Resist layer forming step>
In the step (F), a plating resist layer is formed on the surface of the metal film formed on the adhesion resin layer.
More specifically, as shown in FIG. 2A, a plating resist layer 30 is formed on the surface of the conductive metal film 28.
The plating resist layer can be formed by a known method, and a general dry film resist, a solder resist, or the like is used, and a dry film resist is preferable. Any material can be used as the dry film resist, and negative, positive, liquid, and film-like ones can be used.
Although the thickness of the plating resist layer 30 is selected according to the thickness of the wiring to be formed, it is generally preferably 5 to 200 μm. If the thickness is less than 5 μm, the film is easily cut and difficult to handle. On the other hand, it is preferably 200 μm or less from the viewpoint of handling properties such as satisfying folding resistance.

<Process (G): Patterning process>
In the step (G), the formed plating resist layer 30 is patterned by pattern exposure and development.
More specifically, as shown in FIG. 2B, the plating resist layer 30 is not provided in the same region as the wiring pattern (metal pattern) to be formed, and plating is performed only in the region where the metal pattern is not formed. A pattern is formed so that the resist layer 30 exists.
As the pattern forming method of the dry film resist, any method used at the time of manufacturing the printed wiring board can be used.

<Process (H): Wiring pattern formation process>
In step (H), electroplating is performed using a plating resist layer to form a wiring pattern.
More specifically, as shown in FIG. 2C, electroplating is performed using the patterned plating resist layer 30 as a mask to form a patterned metal layer 32 in a region where the plating resist layer 30 is not formed. . This forms a further wiring pattern.
The electroplating can be performed by the same method as the electroplating described in the step (B).
The thickness of the formed metal layer 32 is selected according to the purpose of the wiring, but generally it is preferably in the range of 0.3 to 3 μm.

<Step (I): Resist Layer Removal Step>
In step (I), after the formation of the metal layer (wiring pattern), the plating resist layer in the non-wiring pattern portion used for energization of electroplating is removed.
More specifically, as shown in FIG. 2D, after the metal layer 32 is formed, the plating resist layer 30 in the non-wiring region is removed. In this way, as shown in FIG. 2D, a patterned metal layer 32 (wiring pattern) is formed only in the region where the plating resist layer 30 is not formed. As shown in FIG. 2D, the formed patterned metal layer 32 is electrically connected to each other by the lower second conductive layer 24 and the conductive metal film 28 formed on the surface thereof. Therefore, if necessary, quick etching is performed after removing the dry film resist pattern, and unnecessary regions of the second conductive layer 24 and the conductive metal film 28 are removed in a pattern. The formation of the wiring pattern 34 including the conductive layer 24, the conductive metal film 28, and the metal film 32 is completed, and a multilayer wiring board is obtained [FIG. 2 (E)].
As an etching method, any method used at the time of manufacturing a printed wiring board can be used, and either wet etching or dry etching may be used, but wet etching is preferable from the viewpoint of workability. As an etching solution, for example, an aqueous solution of cupric chloride, ferric chloride, or the like can be used.

<Multilayer wiring board>
The multilayer wiring board obtained by the forming method of the present invention can be applied to various uses such as a semiconductor chip, various electric wiring boards, FPC, COF, TAB, a motherboard, a package interposer board, and the like.
In particular, the multilayer wiring board produced by the method of the present invention can easily form wiring with excellent adhesion to a smooth substrate, has good high-frequency characteristics, and is a fine high-density wiring. Excellent connection reliability between wires.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

Below, the synthesis method of the polymer used in a present Example is explained in full detail.
(Synthesis Example 1: Polymer A)
A 1000 ml three-necked flask was charged with 35 g of N-methylpyrrolidone and heated to 75 ° C. under a nitrogen stream. There, N-methylpyrrolidone 35 g solution of 6.60 g of 2-hydroxyethyl acrylate (commercial product, manufactured by Tokyo Chemical Industry), 28.4 g of 2-cyanoethyl acrylate, and 0.65 g of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) The solution was added dropwise over 2.5 hours. After completion of dropping, the reaction solution was heated to 80 ° C. and further stirred for 3 hours. Thereafter, the reaction solution was cooled to room temperature.
Ditertiary butyl hydroquinone 0.29 g, dibutyltin dilaurate 0.29 g, Karenz AOI (manufactured by Showa Denko KK) 18.56 g, and N-methylpyrrolidone 19 g are added to the above reaction solution and reacted at 55 ° C. for 6 hours. Went. Thereafter, 3.6 g of methanol was added to the reaction solution, and the reaction was further performed for 1.5 hours. After completion of the reaction, reprecipitation was carried out with water, the solid matter was taken out, and 25 g of the polymer A of the present invention was obtained.

(Identification of structure)
Polymer A was dissolved in heavy DMSO and measured by Bruker 300 MHz NMR (AV-300). Peaks corresponding to nitrile group-containing units are broadly observed at 4.3-4.05 ppm (2H min), 2.9-2.8 ppm (2H min), 2.5-1.3 ppm (3H min), Peaks corresponding to the polymerizable group-containing units are 7.2 to 7.3 ppm (1 H min), 6.4 to 6.3 ppm (1 H min), 6.2 to 6.1 ppm (1 H min), 6.0 − 5.9ppm (1H min), 4.3-4.05ppm (6H min), 3.3-3.2ppm (2H min), 2.5-1.3ppm (3H min) broadly observed and polymerized It was found that the functional group-containing unit: nitrile group-containing unit = 22: 78 (mol ratio).

(Measurement of molecular weight)
Polymer A was dissolved in THF, and molecular weight was measured using Tosoh high speed GPC (HLC-8220GPC). As a result, a peak appeared at 23.75 minutes, and it was found that Mw = 5300 (Mw / Mn = 1.54) in terms of polystyrene.
In addition, the numerical value in the chemical formula of the following polymer A represents the mol% of each unit.

(Synthesis Example 2: Polymer B)
In a 1 L three-necked flask, 300 mL of ethyl acetate, 30 g of 2-hydroxyethyl methacrylate, and 19.8 g of pyridine were placed and cooled in an ice bath. Thereto was added dropwise 57 g of 2-bromoisobutyric acid bromide so that the internal temperature was 20 ° C. or less. Thereafter, the internal temperature was raised to room temperature (25 ° C.) and reacted for 2 hours. After completion of the reaction, 300 mL of distilled water was added to stop the reaction. Thereafter, the ethyl acetate layer was washed 4 times with 300 mL of distilled water, dried over magnesium sulfate, and after distilling off ethyl acetate, the monomer was purified by column chromatography (25 g).

(Identification of structure)
A 500 mL three-necked flask was charged with 28 g of N, N-dimethylacetamide and heated to 65 ° C. under a nitrogen stream. The monomer synthesized above: 20.9 g, acrylonitrile (Tokyo Chemical Industry Co., Ltd.) 4.0 g, acrylic acid (Tokyo Chemical Industry Co., Ltd.) 8.6 g, V-65 (Wako Pure Chemical Industries, Ltd.) 0.49 g N, N-dimethylacetamide 11.5 g solution was added dropwise over 4 hours. After completion of dropping, the mixture was further stirred for 3 hours. Thereafter, 173 g of N, N-dimethylacetamide was added, and the reaction solution was cooled to room temperature. To the above reaction solution, 0.13 g of 4-hydroxy TEMPO (manufactured by Tokyo Chemical Industry Co., Ltd.) and 66.8 g of 1,8-diazabicycloundecene were added and reacted at room temperature for 12 hours. Thereafter, 65 g of a 70 mass% methanesulfonic acid aqueous solution was added to the reaction solution. After completion of the reaction, reprecipitation was performed with water, and the solid matter was taken out to obtain 20 g of polymer B (weight average molecular weight 62,000). When the acid value of the obtained polymer B was measured using a potentiometric automatic titrator (manufactured by Kyoto Electronics Industry Co., Ltd.) and a 0.1M sodium hydroxide aqueous solution as the titrant, the acid value of this specific polymer B was It was 3.2 mmol / g.

The obtained polymer B was identified using an IR measuring machine (manufactured by Horiba, Ltd.). The measurement was performed by dissolving the polymer in acetone and using KBr crystals. As a result of IR measurement, a peak was observed in the vicinity of 2240 cm ⁻¹ and it was found that acrylonitrile, which is a nitrile unit, was introduced into the polymer. Moreover, it was found from the acid value measurement that acrylic acid was introduced as a carboxylic acid unit. Moreover, it melt | dissolved in heavy DMSO (dimethyl sulfoxide), and measured by NMR (AV-300) of Bruker 300MHz. A peak corresponding to the nitrile group-containing unit is broadly observed at 2.5 to 0.7 ppm (5H min), and a peak corresponding to the polymerizable group-containing unit is 6.2 to a peak corresponding to the polymerizable group-containing unit. Broadly observed at 6.0 ppm (1H min), 5.8-6.0 ppm (1H min), 4.4-4.0 ppm (4H min), 2.5-0.7 ppm (8H min), A peak observed broad and a peak corresponding to a carboxylic acid group unit was observed broadly at 2.5 to 0.7 ppm (3H min), and a polymerizable group-containing unit: nitrile group-containing unit: carboxylic acid group unit = 31: 32 : 37 (mol ratio).

<Example 1>
[1. Preparation of insulating layer]
An epoxy insulating film GX-13 (film thickness 45 μm) manufactured by Ajinomoto Fine Techno Co., Ltd. is heated and pressurized as an electrical insulating layer on a glass epoxy substrate on which a first conductive layer (copper foil) is formed in advance. The insulating film was formed by bonding with a vacuum laminator at a pressure of 0.2 MPa under conditions of 100 to 110 ° C.

[2. Preparation of adhesion auxiliary layer]
Next, JER806 (bisphenol F type epoxy resin: made by Japan Epoxy Resin) 11.8 parts by mass, LA7052 (phenolite, curing agent: Dainippon Ink and Chemicals) 4.8 parts by mass, YP50-35EK (phenoxy resin, Toto) Kasei) 21.7 parts by mass, 61.6 parts by mass of cyclohexanone, and 0.1 parts by mass of 2-ethyl-4-methylimidazole (curing accelerator) were mixed into a filter cloth (mesh # 200). And filtered to prepare a coating solution.
This coating solution was applied to the substrate with a spin coater (rotated at 300 rpm for 5 seconds and then rotated at 1500 rpm for 20 seconds), and then dried and cured at 180 ° C. for 30 minutes. Thereby, a substrate A1 was obtained. The thickness of the cured adhesion auxiliary layer was 1.0 μm. The surface roughness (Ra) of the substrate A1 was 0.10 μm (200 μm ² ).

[3. Preparation of coating solution (composition for forming adhesive resin layer) and preparation of adhesive resin layer]
To 7% acetonitrile solution of polymer A having a polymerizable group and an interactive group, 20 parts by mass of synthetic rubber [Nipol 1041, trade name: manufactured by Nippon Zeon Co., Ltd.] is added to 100 parts by weight of polymer A, and an adhesive resin layer A coating solution for forming composition 1 was prepared.

The prepared coating solution was applied onto the adhesion auxiliary layer of the substrate A1 by a spin coater (rotated at 300 rpm for 5 seconds and then rotated at 750 rpm for 20 seconds) and dried at 80 ° C. for 30 minutes. After drying, using a UV exposure machine (model number: UVF-502S, lamp: UXM-501MD) manufactured by Mitsunaga Electric, an irradiation power of 10 mW / cm ² through a quartz mask (Ushio's UV integrated light meter UIT150) -Irradiation power measurement with the light receiving sensor UVD-S254), irradiation was performed for 100 seconds, a graft polymer was generated on the entire surface of the adhesion auxiliary layer, and an adhesion resin layer containing a polymer directly bonded to the adhesion assistance layer was formed. The integrated exposure amount was 500 mJ.

  Thereafter, the substrate on which the graft polymer was formed was immersed in acetonitrile in a stirred state for 5 minutes, and then washed with distilled water. Thereby, the laminated body which has an adhesion resin layer was obtained. The thickness of the adhesive resin layer was 0.3 μm.

[4. Application of plating catalyst]
The obtained laminate was immersed in a 0.05% by mass acetone solution of palladium nitrate for 30 minutes, and then washed with acetone and distilled water for 1 to 2 minutes, respectively.

[5. Electroless plating]
As described above, the laminated body provided with the plating catalyst was subjected to electrolysis plating using Urumura Kogyo Co., Ltd. sulcup PGT, using an electroless plating bath having the following composition at an electroless plating temperature of 26 ° C. for 60 minutes. Plating was performed to obtain a laminate having a second conductive layer on the surface of the laminate. The thickness of the obtained electroless copper plating film was 1.0 μm.
The preparation order and raw materials of the electroless plating solution are as follows.
Approximately 60% by volume of distilled water
PGT-A 9.0% by volume
PGT-B 6.0% by volume
PGT-C 3.5% by volume
Formalin solution * 2.3% by volume
Finally, the liquid level was adjusted with distilled water so that the total amount would be 100% by volume.
* The formalin used here is a Wako Pure Chemical formaldehyde solution (special grade).

[6. Formation of vias]
Using a UV-YAG laser, a via hole reaching the surface of the first conductive layer having a top diameter of 60 μm is adjusted at a frequency of 5000 Hz with a shot number of 200 to 300 and a pulse energy of 0.05 to 0.12 mJ. Formed.

[7. Desmear processing]
As the desmear formulation, MLB213A (Rohm and Hearth) was prepared by immersing the laminate for 7 minutes at 70 ° C. in a swelling bath containing 20% by volume of MLB211 (manufactured by Rohm and Haas Electronic Materials Co., Ltd.) and 10% by volume of Cuposit Z. An immersion bath containing 10% by volume of Electronic Materials Co., Ltd. and 15% by volume of MLB213B (Rohm and Haas Electronic Materials Co., Ltd.) was immersed for 10 minutes at 80 ° C., and MLB 216-2 (Rohm and Haas Electronic Materials Co., Ltd.) The via hole was subjected to desmear treatment by immersing in a neutralization bath containing 20% by volume of the product (made by company) at 45 ° C. for 7 minutes.

[8. Carbon catalyst]
To 200 g of distilled water at 25 ° C., 4.0 g of sodium linolenate was added. Then, 4.0 g of graphite (manufactured by Ito Graphite Industries, CP-2, average particle diameter 2 μm, BET specific surface area 20 m ^{2 /} g) was added and stirred for 30 minutes to obtain a dispersion.
The laminate subjected to desmear treatment was immersed in the obtained dispersion (25 ° C.) for 15 minutes to give graphite to the via hole wall surface.

[9. Cleaning process]
In order to remove excess graphite catalyst adhering to the first conductive layer and the second conductive layer, sulfuric acid / hydrogen peroxide aqueous solution at 25 ° C. (100 g of distilled water, 16 g of sulfuric acid 3.2N, 90 g of hydrogen peroxide) The laminate was immersed in it for 40 seconds.

[10. Formation and patterning of plating resist layer for electroplating]
After washing the copper surface with a 1% aqueous sulfuric acid solution, a dry film resist (ALPHA NIT3025: manufactured by Nichigo Morton Co., Ltd.) was laminated at a temperature of 110 ± 10 ° C. and a pressure of 0.35 ± 0.05 Mpa. The circuit pattern was baked by irradiating ultraviolet rays at 120 mJ / cm ² with an ultra-high pressure mercury lamp with reference to the guide hole, and then sprayed at 30 ° C. with a 1% aqueous sodium carbonate solution. The dry film resist was developed at 15 MPa to form a plating resist pattern.

[11. Electroplating]
Using the first conductive layer, the second conductive layer, and the applied carbon catalyst as a power feeding layer, electroplating was performed for 45 minutes under the condition of 3 A / dm ² using an electrolytic copper plating bath having the following composition. The thickness of the obtained electrolytic copper plating film was 20 μm.

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

[12. Stripping and etching resist
The plating resist pattern was stripped and removed by applying it to the surface at a spray pressure of 0.2 MPa at 80 ° C. for 100 seconds using a 4 mass% sodium hydroxide aqueous solution as the resist stripping solution. Thereafter, the wiring pattern 34 was prepared by removing the copper used as the underlying conductive layer in the non-circuit pattern portion with a perhydrosulfuric acid-based soft etching solution (see FIG. 3).
After the above steps, the obtained substrate was washed with water to obtain a semi-additive pattern in which interlayer connections were made by blind vias. Specifically, 20 units of via chains (daisy chains) (see FIG. 3) connected with 100 50 μmφ blind vias were produced. The evaluation test mentioned later was done using this unit.

<Example 2>
It implemented in Example 1 [5. The electroless plating] treatment time was changed to 20 minutes to produce an electroless copper plating having a thickness of 0.3 μm. Subsequently, the copper plating was used as a power feeding layer, and an electrolytic copper plating bath having the following composition was used. 3A / dm ^A multilayer wiring board was produced in the same manner as in Example 1 except that electroplating was performed for 10 minutes under the condition ² to obtain a copper plating having a thickness of 5 μm.

(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 3>
A multilayer wiring board was produced in the same manner as in Example 1 except that Polymer B was used instead of Polymer A used in Example 1.

<Example 4>
It implemented in Example 1 [8. Carbon catalyst addition] and [9. Instead of the “cleaning step”, the carbon catalyst is adsorbed and washed on the via wall surface by the following [Adsorption of dispersion liquid on the via wall surface (“MacDermide Blackhole ™ SP solution”)]. Otherwise, Example 1 Similarly, a multilayer wiring board was produced.

[Adsorption of dispersion on via wall (“MacDermid Blackhole ™ SP solution”)]
The laminate subjected to desmear treatment in 6 g / L of 2.5-dinonylimidazole aqueous solution (pH 4.4, adjusted with acetic acid) was immersed for 1 minute at 35 ° C. and rinsed. Next, the laminate was immersed in a dispersion “MacDermid Blackhole ™ SP solution” manufactured by MacDermid for 5 minutes at 54 ° C. and washed with water. Further, the laminate was taken out by immersing in the dispersion at 32 ° C. for 90 seconds and forcibly air-dried. Then, it heat-dried at 85 degreeC for 1 minute.
Further, the laminate was immersed in a 5% aqueous hydrochloric acid solution at 38 ° C. for 1 minute and washed with water. Excess carbon catalyst was removed, and the carbon catalyst was adsorbed only on the via wall surface.

<Example 5>
[8. Carbon catalyst addition] is changed as in the following procedure A, and further [9. A multilayer wiring board was manufactured in the same manner as in Example 1 except that the cleaning step] was changed as in Procedure B below.

Procedure A: “6.5 g of tannic acid was added to 200 g of distilled water at 25 ° C. Thereafter, granular carbon black (manufactured by Mitsubishi Chemical Co., Ltd., brand name # 3230B, average particle size 23 nm, BET specific surface area 220 m ² / g) 4.0 g was added and stirred for 30 minutes to obtain a dispersion liquid, which was immersed in the obtained dispersion liquid (25 ° C.) for 15 minutes to conduct electricity on the via hole wall surface. Added carbon black. "
Procedure B: “To remove excess carbon black catalyst adhering to the first conductive layer and the second conductive layer, an aqueous sulfuric acid / hydrogen peroxide solution at 25 ° C. (100 g of distilled water, 16 g of sulfuric acid 3.2N, The laminate was immersed in 90 g of hydrogen oxide water for 40 seconds. "

<Comparative Example 1>
[8. A multilayer wiring board was fabricated in the same manner as in Example 1 except that the treatment described in the following [Electroless plating catalyst application and electroless plating] was performed instead of the treatment performed in [Carbon catalyst application]. Produced.

[Application of electroless plating catalyst and electroless plating]
The laminate having via holes was immersed in a 0.05% by mass acetone solution of palladium nitrate for 30 minutes, and then washed with acetone and distilled water for 1 to 2 minutes, respectively.
The laminate with the plating catalyst applied to the wall surface of the via hole is subjected to electroless plating for 20 minutes at an electroless plating temperature of 26 ° C. using an electroless plating bath of the following composition, using Sulcup PGT manufactured by Uemura Kogyo Co., Ltd. Then, an electroless copper plating film (thickness: 0.3 μm) was produced so as to make the first conductive layer and the second conductive layer conductive.
The preparation order and raw materials of the electroless plating solution are as follows.
Approximately 60% by volume of distilled water
PGT-A 9.0% by volume
PGT-B 6.0% by volume
PGT-C 3.5% by volume
Formalin solution * 2.3% by volume
Finally, the liquid level was adjusted with distilled water so that the total amount would be 100% by volume.
* The formalin used here is a Wako Pure Chemical formaldehyde solution (special grade).

<Comparative example 2>
Epoxy prepreg (semi-cured insulating film; manufactured by Hitachi Chemical Co., Ltd., MCL-E-67N) reinforced with glass fiber having a thickness of 0.06 mm on a glass epoxy substrate on which a first conductive layer (copper foil) is formed in advance ) In a vacuum press at a pressure of 5 MPa and a curing temperature of 180 ° C. for 1 hour, and then [4. Application of plating catalyst], [5. Electroless plating], [6. Formation of vias], [7. Desmear treatment] was performed.

  Thereafter, the [dispersion of the dispersion (“MacDermid Blackhole ™ SP solution”) on the via wall surface] performed in Example 4 was performed, and then [10. Formation and patterning of plating resist layer for electroplating] to [12. Removal of resist and etching] were performed, and a multilayer wiring board was manufactured.

In Comparative Example 1 described above, a multilayer wiring board was produced using an electroless plating method corresponding to Japanese Patent Application Laid-Open No. 2008-334602 when producing a conductive metal film.
In Comparative Example 2, a multilayer wiring board was produced without using an adhesive resin layer.

<Connection reliability evaluation>
In order to evaluate the connection reliability of the via chain obtained in Examples 1 to 5 and Comparative Examples 1 and 2, the continuity failure rate (initial failure) immediately after the formation of the wiring, and the thermal shock test MIL-STD -883D (environment; liquid phase, temperature range; -65 ° C. + 150 ° C., cycle: 2 minutes) The conduction failure rate after 1000 cycles was examined. In addition, those in which initial failure occurred are excluded from the thermal shock test. Moreover, what was not conducted here was judged as poor conduction. The results are summarized in Table 1.
In addition, although an Example and a comparative example are lab scale products, as for the acceptance criteria in that case, Table 1 "via chain connection failure rate (Total)" is 20% or less.

<Surface roughness of the adhesive resin layer (or insulating layer)>
The copper foil on the via / chain surface obtained in Examples 1 to 5 and Comparative Examples 1 and 2 is etched, and the surface appearance (Ra) of the adhesion resin layer is measured with a non-contact type three-dimensional flatness measuring device ( VeriFire ^™ XP / D, manufactured by Zygo). The results are summarized in Table 1.
In Comparative Example 2, the surface roughness of the insulating layer was measured instead of the adhesive resin layer.

<Stripping strength of surface copper foil (90 ° peel strength)>
For the via substrates obtained in Examples 1 to 5 and Comparative Examples 1 and 2, the surface copper foil 90 was subjected to the method described in JIS C 6481 (1996) copper-clad laminate test for printed wiring boards. Detachment test was conducted. The test machine used Autograph AGS-J made by Shimadzu Corporation, the width of the copper foil to be peeled off was 10 mm, the peeling speed was 50 mm per minute, the number of measurements was N = 5, and the average value was calculated. . The results are summarized in Table 1.
From a practical point of view, the peel strength needs to be 0.6 to 0.7 N / mm or more.

<Yield evaluation>
The surface layer copper wiring (corresponding to the wiring pattern 34 in FIG. 3) patterned by the semi-additive method of Examples 1 to 5 and Comparative Examples 1 and 2 is LS: 10 μm, wiring thickness: 20 μm, wiring length Was 4 mm. The surface inspection was performed for every 200 wirings, the number of wiring distortions, peeling / falling, and disappearances was examined, and the ratio (yield defect rate) was calculated. The results are summarized in Table 1.
In addition, although an Example and a comparative example are lab scale products, as for the acceptance criteria in that case, Table 1 "fine wiring yield defect (LS10micrometer defect rate)" is 20% or less.

In Examples 1 to 5 obtained by the production method of the present invention, the connection failure rate and the yield failure rate of fine wiring are low, and the adhesiveness of the copper foil (metal film) formed on the surface is also excellent. It was.
On the other hand, in Comparative Example 1 in which electroless plating was performed without using a conductive catalyst, both the connection failure rate and the yield of fine wiring were high. Although the via wall surface and the via bottom portion of Comparative Example 1 are joined by electroless plating and electroplating, the adhesion between the electroless plating film and the electroplating film tends to be generally low. Due to such a low adhesion, via connection failure is expected.
Further, Comparative Example 1 has a high 90 ° peel strength measured under the conditions of JIS C 6481 (1996). On the other hand, in the fine wiring, the degree of in-plane variation of the adhesion force on the wiring scale is more important than the value of the adhesion force of 1 cm width size, but this measurement is difficult. The reason for the high yield failure in Comparative Example 1 is that the planar region has a structure in which in-plane variation, particularly in microscale, tends to be large, such as lamination of an electroless plating film and an electroplating film. ,I think that the.
Further, Comparative Example 2 in which the adhesive resin layer is not used has a high connection failure rate and yield failure. In Comparative Example 2, since the surface roughness of the insulating layer is large, it can be determined that the yield defect rate is extremely high. On the other hand, the reason why the connection failure rate of Comparative Example 2 is low is that the adhesive resin layers of Examples 1 to 5 function as stress relaxation layers, which showed an effect more than expected, and extremely severe conditions of thermal shock. Is mentioned. As a result, it seems that the difference between the comparative example 2 and the examples 1 to 5 appears remarkably.

10: Wiring substrate 12: Substrate 14: First conductive layer 16: Insulating layer 18: Adhesion auxiliary layer 20: Adhesion resin layer 22, 36: Laminate 24: Second conductive layer 26: Via hole 28, 42: For conduction Metal film 30: Plating resist 32: Metal layer 34: Wiring pattern

Claims (4)

(A) Applying energy to the insulating substrate and a layer containing a polymer having a functional group and a polymerizable group that interact with the plating catalyst or its precursor on the surface of the wiring board including the first conductive layer. Forming a laminate comprising the resulting adhesive resin layer in this order;
(B) After providing the plating resin or precursor thereof to the adhesion resin layer after the step (A), performing plating, and forming a second conductive layer on the adhesion resin layer;
(C) After the step (B), a via hole is formed by laser processing or drilling so as to penetrate the second conductive layer, the adhesion resin layer, and the insulating layer and reach the first conductive layer. And a process of
(D) After the step (C), performing a desmear process;
(E) After the step (D), after applying carbon black or graphite to the wall surface of the via hole, electroplating is performed without performing electroless plating, and the first conductive layer and the second conductive layer And a step of electrically connecting the conductive layer.   The method for manufacturing a multilayer wiring board according to claim 1, wherein the thickness of the second conductive layer is 0.2 to 20 μm.   The manufacturing method of the multilayer wiring board of Claim 1 or 2 whose functional group which forms an interaction with the said plating catalyst or its precursor is a cyano group or a carboxylic acid group. The manufacturing method of the multilayer wiring board in any one of Claims 1-3 with which the said laminated body is further provided with the close_contact | adherence auxiliary | assistant layer between the said insulating layer and the said close_contact | adherence resin layer.