JP2009196249A - Laminate and manufacturing method of laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate showing high adhesion between a metallic thin film and a substrate, having the same conductivity as a bulk metallic thin film, showing superiority in fine wiring formability and moisture resistance and causing very little discoloration of a wiring end portion after electroless tin plating, and to provide its manufacturing method. <P>SOLUTION: The laminate contains an insulating resin layer and a metallic thin film layer formed on the insulating resin layer wherein the insulating resin layer is composed of a metal alloy comprising two or more kinds of metals, and a metal oxide exists on the boundary surface between the insulating resin layer and the metallic thin film layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a metal laminated substrate suitably used for an electric wiring circuit board such as a printed wiring board and a method for manufacturing the same.

Conventionally, vacuum deposition methods, sputtering methods, CVD methods, plating methods, metal paste methods, and the like are known as methods for forming a metal thin film on a substrate.
According to the plating method, it is possible to form a metal thin film on a conductive substrate relatively easily. However, when forming on an insulating substrate, it is necessary to form a conductive layer first. Therefore, there is a problem that the process becomes complicated. In addition, since the plating method uses a reaction in a solution, a large amount of waste liquid is produced as a by-product, and there is a problem that this waste liquid treatment requires a lot of labor and cost, and the adhesion of the resulting metal thin film to the substrate Is not enough.

In a vapor phase method such as a vacuum deposition method, a sputtering method, or a CVD method, the substrate surface is usually subjected to a surface treatment such as a plasma treatment before the metal thin film is formed, but the substrate may be damaged by this surface treatment. For example, Patent Document 1 discloses that when a polyimide film is subjected to plasma treatment, an imide ring in a surface layer is cleaved, and oxygen functional groups and nitrogen functional groups are generated due to differences in oxygen concentration conditions. In this document 1, after performing plasma treatment under the condition of oxygen concentration (1-10) × 10 ⁻⁶ Pa, the initial adhesive strength is 1 kN due to the interaction between the nitrogen functional group and copper by vapor deposition of copper. Although there is a description that a laminate of about / m can be obtained, the presence of a nitrogen functional group generated by the modification of the polyimide is said to decrease film properties such as a decrease in heat resistance of the polyimide film and an increase in hygroscopicity. There's a problem.

  The metal paste method is a method in which a metal thin film is obtained by applying a solution in which a metal filler is dispersed onto an insulating substrate, and performing heat treatment. According to this method, there is an advantage that a special apparatus such as a vacuum apparatus is not required and the process is simple. However, in order to melt the metal filler, a high temperature of 1000 ° C. or higher is usually required. Accordingly, the base material is limited to those having heat resistance such as a ceramic base material, and there is a problem that the base material is damaged by heat or the base material is easily damaged by residual stress generated by heating. Furthermore, the adhesion of the resulting metal thin film to the substrate is not sufficient.

  Patent Document 2 describes that adhesion to a substrate is improved by applying a mixture of metal powder and a reactive organic medium onto a coating layer that is a diffusion and adhesion barrier such as a soluble polyimide and heat-treating the mixture. There is. For example, when forming a copper film from a mixture of copper powder and a copper-based reactive organic medium, a protective atmosphere (a nitrogen atmosphere with an oxygen concentration of less than 3 ppm or a reducing atmosphere containing hydrogen) is used to prevent copper oxidation. Although heat treatment in the inside is preferable and in that case, there is a description that the adhesiveness enough to clear the tape test is obtained, the adhesive strength is about 1 kN / m, which is not sufficient. In addition, since metal powder of 2 to 10 μm is used, the interface roughness between the metal film and the substrate is large, and there is a problem that it is difficult to form fine wiring in applications where the metal film is formed by photolithography.

  On the other hand, a technique for reducing the firing temperature of the metal paste by reducing the particle size of the metal filler is known. For example, Patent Document 3 uses a dispersion in which metal fine particles having a particle size of 100 nm or less are dispersed. A method of forming a metal thin film directly on an insulating substrate is disclosed. However, the adhesion of the metal thin film produced by this method to the insulating substrate is not sufficient. Furthermore, the method for producing metal particles of 100 nm or less used here is a method for rapidly cooling metal vapor volatilized in a low-pressure atmosphere, so that mass production is difficult and therefore the cost of the metal filler is increased. Have a problem.

  A method of forming a metal thin film directly on an insulating substrate using a metal oxide paste in which a metal oxide filler is dispersed is also known. Patent Document 4 discloses a method for obtaining a metal thin film by heating a metal oxide paste containing a crystalline polymer and dispersing a metal oxide having a particle size of 300 nm or less to decompose the crystalline polymer. Yes. However, in this method, it is necessary to disperse a metal oxide of 300 nm or less in the crystalline polymer in advance, and in addition to requiring a great effort, in order to decompose the crystalline polymer, 400 ° C. to A high temperature of 900 ° C. is required. Therefore, the usable base material has a problem that it requires heat resistance equal to or higher than its temperature and has a limitation on its kind. Further, the adhesion of the obtained metal thin film to the substrate is not sufficient.

As a method of manufacturing a metal thin film that solves these problems, the present applicant has already applied a dispersion in which an inexpensive metal oxide filler is dispersed on a substrate, and then applied the metal thin film by heat treatment at a relatively low temperature. The method of obtaining is disclosed (Patent Document 5). With this technology, it is possible to easily form a thin metal film such as thin copper or the like on a substrate, and to form a copper film on a polyimide film, etc., and use it as a material for flexible printed wiring boards. However, with the progress of miniaturization of wiring, further improvement in chemical resistance is required.
JP 2005-54259 A Special table 2003-506882 gazette Japanese Patent No. 2561537 Japanese Patent Laid-Open No. 5-98195 WO03 / 051562 pamphlet

The problem of the present invention is that the adhesion between the metal thin film and the substrate is high, the electroconductivity is equivalent to that of the bulk metal thin film, the fine wiring formability and the moisture resistance are excellent, and the electroless tin plating. It is an object of the present invention to provide a laminate and a method for manufacturing the same, in which discoloration of the wiring end portion when performing is performed.
Another object of the present invention is to provide a method for forming a metal thin film having high adhesion on a substrate without requiring modification of the substrate by plasma treatment or the like and without requiring high temperature.

As a result of diligent investigations to solve the above problems, the present inventors have completed the present invention.
That is, the present invention is as follows.

  The laminate of the present invention has particularly high adhesion between the metal thin film and the substrate, excellent properties such as fine wiring formability and moisture resistance, and extremely little discoloration at the end of the wiring when electroless tin plating is performed. . Further, according to the present invention, the film thickness of the metal can be arbitrarily controlled, and a thin metal film can be easily formed, so that it can be suitably used as a printed wiring board material.

The present invention is described in detail below.
The laminate of the present invention is a laminate comprising an insulating resin layer and a metal thin film layer formed on the insulating resin layer, and the metal thin film layer is an alloy layer composed of two or more kinds of metals. The metal oxide is present at the contact interface between the insulating resin layer and the metal thin film layer.
When the metal thin film layer is made of an alloy layer composed of two or more kinds of metals, it is possible to exhibit particularly high chemical resistance in addition to properties such as adhesion, fine wiring formability, and moisture resistance. Examples of the metal species constituting the alloy include Ag, Cu, Al, Ni, Pd, Cr, Sn, Zn, and Mn.

The metal thin film layer preferably contains Cu, and the metal-derived peak position near 43 ° measured by X-ray analysis is 42.5 ° to 44.4 excluding the peak position 43.305 ° of Cu (100). Laminations characterized by a range of 0 ° are preferred because they are particularly excellent in chemical resistance. The laminated body in which the metal thin film layer includes Cu and at least one selected from Sn, Ni, Co, Mn, Zn, and Cr is particularly preferably used because it has excellent fine circuit formation.
The laminate of the present invention can be used by being laminated on an insulating substrate, for example. The insulating substrate used in this case may be either an organic material or an inorganic material, but a heat-resistant substrate is preferable because a heat treatment is performed when forming the metal thin film. For example, inorganic materials such as ceramics and glass, and heat resistant resins such as polyimide films are preferably used.

The insulating substrate is not particularly limited as long as it has an insulating property of a level normally used for an electric wiring circuit substrate, and preferably has a volume resistivity of 10 ¹³ Ωcm or more.
A thermosetting polyimide film that is particularly preferably used as an insulating substrate is obtained by condensing pyromellitic acid or a pyromellitic acid derivative and an aromatic diamine, such as Kapton (registered trademark, manufactured by Toray DuPont Co., Ltd.). ), Apical (registered trademark, manufactured by Kaneka Chemical Co., Ltd.), and the like, which are obtained by condensing biphenyltetracarboxylic acid or a biphenyltetracarboxylic acid derivative and an aromatic diamine, such as Upilex (registered trademark, Ube Industries, Ltd.) Etc.). Although the film thickness of a polyimide film is not limited, Usually, about 25-100 micrometers can be suitably selected and used according to a use.

The insulating substrate may be used as it is, but in order to improve the adhesion with the insulating resin layer formed thereon, degreasing treatment, chemical treatment with acid or alkali, heat treatment, plasma treatment, corona discharge treatment, sandblast treatment A surface treatment such as the above may be performed.
In the present invention, an insulating resin layer is formed, and a metal thin film is further laminated thereon. The insulating resin exhibits an adhesive strength between the metal thin film layer and is not particularly limited as long as it does not cause a problem in wiring processing. However, a resin preferable from the viewpoint of the adhesive strength exhibits an imide bond and / or an amide bond. It is a thermoplastic insulating resin.

Examples of the thermoplastic insulating resin having an imide bond and / or an amide bond include thermoplastic polyimide resins, polyamide resins, and polyamideimide resins. A polyimide resin is a resin having an imide bond and is usually obtained by condensing a tetracarboxylic dianhydride component and a diamine component. The polyamide resin is a resin having an amide bond and is obtained by condensing a dicarboxylic acid or a dicarboxylic acid halide component and a diamine component. Polyamideimide resin has both an amide bond and an imide bond. These resins preferably have an insulating property that is usually used as an insulating film for electric wiring, and preferably have an insulating property with a volume resistivity of 10 ¹³ Ωcm or more.

Of the thermoplastic resins having an imide bond and / or an amide bond, a thermoplastic polyimide resin is particularly preferable.
The thermoplastic polyimide resin has a large decrease in elastic modulus due to heating at a glass transition temperature or higher. The glass transition temperature of the thermoplastic polyimide resin is preferably 150 ° C. or higher and 350 ° C. or lower, more preferably 150 ° C. or higher and 300 ° C. or lower, from the viewpoint of the hardness of the polyimide resin and the adhesion between the metal thin film and the insulating substrate. is there.

  Thermoplastic polyimide resin has 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride as a tetracarboxylic acid component. , (3,4-dicarboxyphenyl) sulfone dianhydride, (3,4-dicarboxyphenyl) hexafluoropropane dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 2,2- At least one of bis (3,4-dicarboxyphenyl) propane dianhydride and bis (3,4-dicarboxyphenyl) difluoromethane dianhydride is used, and the diamine component includes [4- (3- Aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phene L] hexafluoropropane, 3,3′-diaminodiphenylsulfone, 3,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4 -(4-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] propane, 3,3′-diaminodiphenylpropane, 3, 3'-diaminobenzophenone, 4,4'-bis (3-aminophenoxy) biphenyl, 2,2-bis (4- (4-aminophenoxy) phenyl) perfluoropropane, 2,2'-bis (4- ( 4-aminophenoxy) using a product obtained by polymerization reaction using at least one of phenylpropane and the like It is preferable.

The thermoplastic polyimide resins may be used singly or in combination of two or more, and a plurality of layers may be formed from resins having different chemical compositions.
The thickness of the thermoplastic insulating resin layer having an imide bond and / or an amide bond is preferably in the range of 0.1 to 20 μm from the viewpoint of adhesion between the insulating substrate and the metal thin film layer, and economical efficiency. 10 μm is more preferable.
In this invention, the metal thin film layer which consists of an alloy layer comprised from 2 or more types of metals is laminated | stacked on the said insulating resin layer.
It is preferable that the interface roughness of the contact interface between the insulating resin layer and the metal thin film layer is less than 100 nm because it is easy to form a fine circuit. Moreover, in order to express high adhesive strength, it is preferable that interface roughness is 2-100 nm, and especially preferable interface roughness is 2-50 nm. It is preferable that the metal particles are embedded in the insulating resin layer at the interface because an adhesion mechanism due to the anchor effect is added, so that particularly high adhesive strength can be expressed. Although there is no restriction | limiting in the thickness of the metal thin film layer in the laminated body of this invention, Usually, it is 0.01-50 micrometers.

In the laminate of the present invention, a metal oxide is present at the contact interface between the insulating resin layer and the metal thin film layer.
The metal oxide present at the interface has an effect of increasing the adhesive strength between the metal thin film layer and the insulating resin layer, and therefore it is preferable that the metal oxide is uniformly distributed over the entire interface. The reason for the effect of increasing the adhesive strength by the metal oxide is not necessarily clear, but for an insulating resin layer having an imide group or an amide group, a preferable chemical bond is formed with the imide group or the amide group. it is conceivable that.

  In the present invention, even if the insulating resin layer is not subjected to imide group or amide group modification treatment by plasma treatment or the like, high adhesive strength is exhibited by the presence of the metal oxide. In plasma treatment, imide groups or amide groups are usually converted to other nitrogen-containing polar groups by the high energy of plasma, which is said to contribute to adhesion improvement. Such polar groups are hygroscopic or metallic. There is a concern of adversely affecting ion migration. The present invention is characterized in that the adhesive strength is high without such treatment.

Although there is no restriction | limiting in particular in the thickness of a metal oxide, Usually, the range of 1 nm-200 nm is preferable from an adhesive strength and electroconductive viewpoint. Examples of the metal oxide include copper oxide, nickel oxide, cobalt oxide, silver oxide, ruthenium oxide, osmium oxide, manganese oxide, molybdenum oxide, and chromium oxide. In particular, when the metal oxide contains copper oxide and another metal oxide different from copper oxide, chemical resistance is particularly improved, which is preferable. Of the copper oxides, cuprous oxide is particularly preferable.
The laminate having a metal plating layer by further plating on the metal thin film layer described above is preferable because the metal plating layer can add characteristics such as electrical characteristics and mechanical characteristics to the metal thin film layer. . Although there is no restriction | limiting in particular in the metal seed | species of a metal plating layer, Copper, nickel, gold | metal | money, etc. are preferable from a viewpoint of electroconductivity or stability. Copper is particularly preferred because of its low resistance value and industrial availability. Although there is no restriction | limiting in the thickness of a metal plating layer, Usually, it is 0.05-50 micrometers.

Next, the manufacturing method of the laminated body of this invention is demonstrated.
The method for producing a laminate of the present invention includes a step (1) of forming an insulating resin layer, and a step (2) of forming an alloy layer composed of two or more metals on the insulating resin layer. And (3) forming a metal oxide at the interface between the alloy layer and the insulating resin layer.
The insulating resin layer can be formed on an insulating substrate, for example, and the step of forming the insulating resin layer is performed by applying a drying treatment by applying an insulating resin solution on the insulating substrate, or by insulating the insulating resin layer. Examples thereof include a method of forming an insulating resin layer by applying a resin precursor solution on an insulating substrate and performing heat treatment.

  For example, a method for forming a thermoplastic polyimide resin layer is a method of forming a layer made of a thermoplastic polyimide resin on an insulating substrate by applying a solution of the thermoplastic polyimide resin on the insulating substrate and then performing a solvent removal process (A -1) and a method of forming a layer made of a thermoplastic polyimide resin on an insulating substrate by applying a solution of a thermoplastic polyimide resin precursor on the insulating substrate and then performing a heat treatment for solvent removal and dehydration condensation reaction (A-2).

  In the method (A-1), the solvent is removed from the thermoplastic polyimide resin solution coated on the insulating substrate by a method such as heat treatment. At this time, it is preferable to perform the heat treatment while gradually raising the temperature from a low temperature to a high temperature. When the heat treatment is suddenly performed at a high temperature, a skin layer may be formed on the resin surface, and the solvent may not easily evaporate or may foam.

  According to the method (A-2), after applying the thermoplastic polyimide resin precursor solution, the solvent is removed by heat treatment, and imide ring closure is performed by dehydration condensation reaction. Regarding this heat treatment, the solvent removal treatment and the imide ring closure treatment may be performed simultaneously or sequentially. It is desirable to perform the heat treatment while gradually raising the temperature from a low temperature to a high temperature. It is also possible to use a plurality of polyimide precursors in a laminated manner. In this case, in order to provide sufficient adhesion between the polyimide resin layers in the laminate, a plurality of precursor solutions can be applied collectively or sequentially. Or after the solvent removal treatment at a temperature equal to or lower than the imide ring-closing reaction temperature, the heat conversion of the precursor to polyimide is preferably performed collectively. Examples of the polyimide resin precursor include compounds that produce thermoplastic polyimide by heating, such as polyamic acid and diisocyanate adducts.

  The method of applying a solution of a thermoplastic insulating resin or a thermoplastic insulating resin precursor having an imide bond and / or an amide bond is not limited. For example, dip coating, bar coating, spin coating, roll A coat, a spray coat, etc. are used. An organic solvent is usually used as the solvent used in the solution at the time of application. Examples of the organic solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, 1,3-dimethyl-2-imidazolidinone, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethylsulfoxide, dimethylsulfone, hexamethylphosphoramide, tetramethylurea, N-methylcaprolactam, ptirolactam, tetrahydrofuran, m-dioxane, p-dioxane, 1,2-dimethoxyethane, bis (2- Methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis-2- (2-methoxyethoxy) ethyl ether, 1,3-dioxane, 1,4-dioxane, cyclohexanone, pyridine, picoline, etc. It is done. These solvents may be used alone or in combination of two or more.

  The concentration of the solution depends on the degree of polymerization of the insulating resin or insulating resin precursor having an imide bond and / or an amide bond, but is usually 5 to 30% by weight from the viewpoint of film thickness adjustment and from the viewpoint of solution viscosity. And preferably 10 to 20% by weight. When the solution viscosity is high, various additives such as a smoothing agent, a leveling material, and a defoaming agent for imparting smoothness to the coating film surface can be added as necessary. In order to adjust the evaporation rate of the solvent, an aromatic hydrocarbon solvent can be used as long as it dissolves uniformly. Furthermore, you may add various additives and catalysts, such as well-known hardening | curing agents, such as an amine type hardening | curing agent, adhesiveness imparting agents, such as a silane coupling agent and an epoxy compound, and flexibility imparting agents, such as rubber | gum.

In the method for producing a laminate of the present invention, following the formation of the insulating resin layer (step (1)), an alloy layer composed of two or more kinds of metals is formed on the resin layer (step (2). )). As long as the alloy layer can be formed, the method for forming these metal thin film layers is not particularly limited, and includes dry plating methods such as sputtering, vacuum deposition, and ion plating, and wet plating methods such as electroless plating and electrolytic plating. Such a method is applicable.
As a method for forming an alloy layer, a method in which a dispersion or solution containing two or more kinds of metal thin film precursors is applied and heat-treated is also applicable.

  The metal thin film precursor refers to a metal and a metal compound that can form a metal thin film by post-treatment such as heat treatment. For example, metal fine particles, metal oxide fine particles, metal hydroxide, and the primary particle size fused to each other by heat treatment Examples include metal thin film precursor fine particles of 200 nm or less, metal complexes or metal salts that are reduced to metal by heat treatment to form a metal thin film. Examples of metal complexes or metal salts that form a nickel thin film by heat treatment include nickel acetylacetone complex, nickel hydroxide, nickel oxalate, nickel formate, and the like.

In order to form a relatively thick metal thin film, a dispersion of metal thin film precursor fine particles having a primary particle diameter of 200 nm or less is particularly preferable among dispersions or solutions containing a metal thin film precursor.
Metal thin film precursor fine particles that are fused to each other by heat treatment means that a dispersion containing the precursor fine particles is applied in the form of a film, and the metal fine particles are joined to each other by heating to form an apparently continuous metal. Fine particles forming a thin film formed of layers.
The metal thin film precursor fine particles have a primary particle diameter of 200 nm or less, preferably 100 nm or less, more preferably 30 nm or less, from the viewpoint that a dense metal thin film is obtained by heat treatment. Moreover, it is preferable that a primary particle diameter is 1 nm or more from a viewpoint of the viscosity of a dispersion, and handleability.

The metal thin film precursor fine particles that can be used are not limited as long as the metal thin film is formed by heat treatment. From the viewpoint of the stability of the dispersion, metal fine particles, metal hydroxide fine particles, and metal oxidation are preferable. Substance fine particles, metal salt fine particles, and metal complex fine particles.
As the metal fine particles, metal fine particles formed by a method such as a wet method or a gas evaporation method are preferable, and copper fine particles are particularly preferable as the metal fine particles that give a copper thin film.
Examples of the metal hydroxide fine particles include fine particles made of a compound such as copper hydroxide, nickel hydroxide, and cobalt hydroxide, but copper hydroxide fine particles are particularly preferable as the metal hydroxide fine particles that give a copper thin film.

The metal oxide fine particles are particularly preferable from the viewpoint of dispersibility in a dispersion medium and ease of forming a metal thin film by heat treatment. Examples of the metal oxide fine particles include copper oxide, silver oxide, palladium oxide, nickel oxide and the like. As the copper oxide capable of providing copper by heat treatment, any of cuprous oxide, cupric oxide, and other copper oxides having an oxidation number can be used. Cuprous oxide fine particles are particularly preferred because they can be easily reduced.
In order to obtain an alloy layer from a metal thin film precursor, precursors that give different metals may be combined to form a dispersion. Examples thereof include a combination of cuprous oxide fine particles and nickel fine particles. In this combination example, the shift position of the Cu (100) peak can be adjusted by adjusting the precursor composition ratio of cuprous oxide and nickel fine particles.

  As a method for forming the alloy layer, a method in which a dispersion or solution containing an alloy thin film precursor is applied and heat-treated is also applicable. The alloy thin film precursor refers to a compound that can form an alloy thin film by post-treatment such as heat treatment, such as precursor fine particles having a primary particle diameter of 200 nm or less that are fused to each other by heat treatment, or an alloy that is reduced to metal by heat treatment. Examples include metal complexes that form thin films. For example, Ni—Cu fine particles, Cu—Cr fine particles and the like are exemplified, and an alloy layer can be obtained by applying a dispersion containing these and performing heat treatment.

When heat-treating the dispersion containing the copper thin film precursor, it is preferable to heat-treat in a non-oxidizing atmosphere in order to prevent the generated copper from being oxidized and impairing conductivity. Examples of the non-oxidizing atmosphere include an inert atmosphere or a reducing atmosphere. Examples of the inert atmosphere include nitrogen, argon, helium, and the like. Examples of the reducing atmosphere include hydrogen, carbon monoxide, and the like. In the reducing atmosphere, an oxidizing gas up to about 1000 ppm which does not impair the reducing ability may be included.
The dispersion medium used for the metal thin film precursor fine particle dispersion is not limited as long as the fine particles can be uniformly dispersed.

It is more preferable that the dispersion contains a polyhydric alcohol and / or a linear aliphatic polyether compound, because the film-forming property when the metal thin film precursor fine particles are obtained by heat treatment is improved.
The polyhydric alcohol is a compound having a plurality of hydroxyl groups in the molecule. The polyhydric alcohol has a moderately high boiling point and thus hardly volatilizes, and it is preferable to use the polyhydric alcohol because it is excellent in the printability of the dispersion and the film formability when forming the metal thin film. Among the polyhydric alcohols, preferred are polyhydric alcohols having 10 or less carbon atoms, and among them, low viscosity, such as ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol. 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, pentanediol, hexanediol, octanediol and the like are particularly preferable. These polyhydric alcohols may be used alone or in combination.

The reason why polyhydric alcohol improves the film-forming property when forming a metal thin film is not necessarily clear, but when the metal thin film precursor fine particles are metal oxide fine particles or metal hydroxide fine particles, the polyhydric alcohol is on the surface of the fine particles. It seems that it acts to protect the particle surface by interacting with the hydroxyl groups of the particles and to suppress aggregation between the particles. Polyhydric alcohol is also preferable because it has an effect of reducing metal oxide fine particles or metal hydroxide fine particles.
When the dispersion contains a linear aliphatic polyether compound, it is preferable because the resistance value of the metal thin film obtained by the heat treatment is reduced in addition to the effect of improving the film formability when forming the metal thin film. The reason why the linear aliphatic polyether compound improves the film formability and reduces the resistance value is that the linear aliphatic polyether compound is a metal thin film precursor during heat treatment as a readily decomposable and easily burnable binder. This is considered to prevent local granulation of fine particles.

The preferred number average molecular weight of the linear aliphatic polyether compound is 150 to 600. When the molecular weight is within this range, the film formability during the formation of the metal thin film is extremely high, and on the other hand, it easily decomposes and burns, so that the volume resistivity of the obtained metal thin film tends to decrease. If the number average molecular weight is less than 150, the film formability when fired to obtain a metal thin film tends to decrease, and if the number average molecular weight exceeds 600, the volume resistivity of the resulting metal thin film tends to increase. is there.
The linear aliphatic polyether compound is preferably an alkylene group having 2 to 6 carbon atoms as a repeating unit. It may be a linear aliphatic polyether compound, a binary or higher polyether tercopolymer, and a polyether block copolymer.

  Specifically, in addition to polyethylene homopolymers such as polyethylene glycol, polypropylene glycol and polybutylene glycol, ethylene glycol / propylene glycol, ethylene glycol / butylene glycol. Binary copolymers of ethylene glycol / propylene glycol / ethylene glycol, propylene glycol / ethylene glycol / propylene glycol, ethylene glycol / butylene glycol / ethylene glycol Examples thereof include, but are not limited to, linear ternary copolymers. As block copolymers, binary block copolymers such as polyethylene glycol polypropylene glycol and polyethylene glycol polybutylene glycol, polyethylene glycol polypropylene glycol, polyethylene glycol, and polypropylene glycol are used. Examples thereof include a polyether block copolymer such as a linear ternary block copolymer such as polyethylene glycol polypropylene glycol and polyethylene glycol polybutylene glycol polyethylene glycol.

  The structure of the terminal of the linear aliphatic polyether compound is not limited as long as it does not adversely affect the dispersibility of the fine particles and the solubility in the dispersion medium, but if at least one terminal is an alkyl group, This is preferable since the decomposition and burn-out property of the polyether compound is improved and the volume resistivity of the resulting metal thin film is lowered. If the length of the alkyl group is too long, the dispersibility of the fine particles tends to be inhibited and the viscosity of the dispersion tends to increase. Therefore, the length of the alkyl group is preferably 1 to 4 carbon atoms. The reason why the decomposition / burning property at the time of firing is improved by having at least one terminal alkyl group is not clear, but hydrogen bonding between the fine particles and the polyether compound or between the polyether compound and the polyether compound, etc. It is surmised that the weakening of the interaction force based on this contributes.

A particularly preferred structure of the linear aliphatic polyether compound is a structure in which one terminal is an alkyl group and the other terminal is a hydroxyl group, and examples thereof include polyethylene glycol methyl ether and polypropylene glycol methyl ether. It is done.
Although there is no restriction | limiting in the ratio of the metal thin film precursor microparticles | fine-particles in a dispersion, It is 5 to 90% by weight with respect to the total amount of a dispersion, More preferably, it is 20 to 80%. When the weight of the fine particles in the dispersion is in these ranges, it is preferable because the fine particles are dispersed, and a metal thin film having an appropriate thickness can be obtained by a single coating / heating treatment.
The ratio of the polyhydric alcohol in the dispersion is, by weight, preferably 5 to 70%, more preferably 10 to 50% with respect to the total amount of the dispersion.

The ratio of the linear aliphatic polyether compound in the dispersion is, by weight, preferably 0.1 to 70%, more preferably 1 to 50%, based on the total amount of the dispersion. When the addition amount of the polyether compound is less than 0.1%, the denseness of the resulting metal thin film may be lowered, or the adhesion to the substrate may be lowered. If the amount of compound added exceeds 70%, the viscosity of the dispersion may increase.
The preferred weight ratio of the polyether compound to the metal thin film precursor fine particles varies depending on the kind of fine particles used and the kind of the polyether compound, but is usually in the range of 0.01 to 10. Within this range, the denseness of the resulting metal thin film is improved, and the volume resistivity is further reduced.

You may add additives, such as an antifoamer, a leveling agent, a viscosity modifier, a stabilizer, to the said dispersion | distribution as needed.
For the production of the dispersion, a general method for dispersing powder in a liquid can be used. For example, after mixing constituent raw materials such as metal thin film precursor fine particles, a dispersion medium, and a linear aliphatic polyether compound, dispersion may be performed by an ultrasonic method, a mixer method, a three-roll method, or a ball mill method. Of these dispersing means, a plurality of dispersing means can be combined for dispersion. These dispersion treatments may be performed at room temperature, or may be performed by heating in order to reduce the viscosity of the dispersion. When the constituents other than the metal thin film precursor fine particles are solid, it is preferable to perform the above operation by adding the fine particles while heating them to a liquid temperature. When the dispersion becomes a flowable solid, the dispersion is preferably performed while applying a shear stress, and a three-roll method, a mixer method, and the like are preferable.

Examples of the method for applying the dispersion or solution of the metal thin film precursor include a dip coating method, a spray coating method, a spin coating method, a bar coating method, a roll coating method, an ink jet method, a contact printing method, and a screen printing method. It is done. What is necessary is just to select the optimal application | coating method suitably according to the viscosity of a dispersion. By adjusting the film thickness of the dispersion to be applied, it is possible to adjust the film thickness of the finally obtained metal thin film.
The applied dispersion or solution is preferable because a dense metal thin film layer may be formed by performing a drying step before heat treatment. The drying process refers to the operation of volatilizing a readily volatile substance such as a dispersion medium at a temperature lower than the temperature at which the metal thin film precursor is converted to a metal thin film. The temperature takes into account the volatilization temperature of the composition constituting the dispersion. However, it is usually performed in a temperature range of 50 to 200 degrees.

When a dispersion or solution of a metal wiring formation precursor is applied to a circuit shape and heated, a metal circuit pattern can be formed. For this application, for example, a drop-on-demand type application device such as an ink jet printer or a dispenser is used. It is done.
In the ink jet method, a dispersion or a solution is placed in an ink jet printer head, and droplets containing a metal thin film precursor are ejected by applying micro vibrations to a piezoelectric element or the like by electric drive. In the dispenser method, a dispersion containing a metal thin film precursor is ejected by putting the dispersion into a dispenser tube having a discharge needle at the tip and applying air pressure.

As the circuit pattern, an arbitrary pattern can be formed by moving an inkjet head or a dispenser discharge needle in a plane direction by a robot. In these coating methods, it is possible to form a circuit that follows a step by moving the robot in the vertical direction even on a substrate having a step.
In the inkjet method, the line width of the wiring pattern to be drawn is controlled by controlling the droplet size ejected from the inkjet printer head and its landing pattern, and in the dispenser method, the line width of the droplet ejected from the ejection needle. Is controlled by the inner and outer diameters of the ejection needle, the ejection pressure, the drawing speed, etc., and the line width of the drawn wiring pattern can be adjusted.

In the application applied to the circuit shape, the line width of the dispersion or solution to be applied is usually in the range of 1 to 400 μm, and the obtained metal wiring has a line width of 0.5 to 300 μm. Moreover, it is possible to adjust the thickness of the metal wiring finally obtained by adjusting the thickness to apply. Usually, the thickness of the dispersion to apply | coat is 0.1-100 micrometers, and the thickness of the metal wiring obtained is 0.05-50 micrometers.
In the method for producing a laminate of the present invention, a metal oxide is formed at the interface between the metal thin film and the insulating resin layer following the formation of the alloy layer on the insulating resin layer (step (2)). (Step (3)).

A preferable method for forming a metal oxide at the interface between the metal thin film and the insulating resin layer is a method in which heat treatment is performed in an inert atmosphere containing an oxidizing agent.
The oxidizing agent is not particularly limited as long as a metal oxide can be formed at the interface between the insulating resin layer and the metal thin film layer, and examples thereof include oxygen, ozone, and water. The concentration of the oxidizing agent in the atmosphere may be appropriately determined in consideration of the ease of oxidation of the metal thin film layer.
The heat treatment is preferably performed at a temperature equal to or higher than the glass transition temperature of the thermoplastic insulating resin, more preferably 40 to 100 ° C. higher than the glass transition temperature, and is usually performed at a temperature of 200 ° C. or higher and 400 ° C. or lower. For example, when a thermoplastic polyimide resin is used and the glass transition temperature is 260 ° C., heat treatment is performed at 300 ° C. to 360 ° C. higher than the glass transition temperature.

  When the metal thin film layer obtained by the heat treatment is a metal species that is susceptible to oxidation, such as copper, it is preferable to heat-treat in a non-oxidizing atmosphere containing an oxidizing agent, particularly preferably oxygen is 20 to 20 Heat treatment in an inert atmosphere adjusted to about 2000 ppm. The inert atmosphere refers to an atmosphere of an inert gas such as argon or nitrogen. When the oxygen concentration is 20 ppm or more, the heat treatment time required for generating the metal oxide at the interface can be shortened. On the other hand, when the oxygen concentration is 2000 ppm or less, the decrease in conductivity of the metal thin film layer can be suppressed. . The heating temperature and the heating time may be appropriately determined in accordance with the susceptibility to interface oxidation and the like, but the heating temperature is usually 200 ° C. to 500 ° C., and the heating time is usually in the range of 1 minute to 120 minutes.

For these heat treatments, a heating means such as a far-infrared ray, infrared ray, microwave, electron beam or other radiation heating furnace, or an electric furnace or oven is used.
The reason why the adhesive strength of the laminate is improved in the production method of the present invention is not necessarily clear, but the adhesion interface with the metal thin film layer is increased by performing a heat treatment at a temperature equal to or higher than the Tg of the thermoplastic insulating resin, It is presumed that the oxide generated at the interface also increases the chemical bond with the insulating resin layer.
A metal plating layer is formed on the metal thin film layer obtained as described above to form a metal plating layer, and functions and characteristics can be imparted to the metal thin film layer. Examples of the technique for performing metal plating on the metal thin film include a dry plating method and a wet plating method. The wet plating method is preferable from the viewpoint of the film formation rate. As the wet plating method, either an electroless plating method or an electrolytic plating method can be used, but the electrolytic plating method is preferable from the viewpoint of the deposition rate of plating and the denseness of the resulting metal film.

  There is no particular limitation on the metal species for plating, but copper, nickel, gold, and the like are preferable from the viewpoint of conductivity and stability. Copper is particularly preferred because of its low resistance value and industrial availability. The plating step is performed by degreasing the surface to be plated and / or removing the oxide layer as necessary, and then immersing the substrate in a plating reaction solution. In the case of electrolytic plating, a plated layer can be formed by energizing the surface to be plated of the substrate.

Examples of the present invention and comparative examples are shown below. The present invention is not limited by these examples.
The particle diameter of metal thin film precursor fine particles, volume resistivity of metal thin film, adhesiveness / adhesive strength, interface roughness and wiring erosion resistance (chemical resistance) in electroless tin plating are as follows. .
(1) Particle diameter of metal thin film precursor fine particles One drop of a dissolved / diluted fine particle dispersion is deposited on a carbon-deposited copper mesh, and a sample dried under reduced pressure is prepared. Using a transmission electron microscope (JEM-4000FX) manufactured by Hitachi, Ltd., select three locations where the particle size is relatively uniform from the field of view. Shoot at a suitable magnification. From each photograph, select the three most likely particles, measure the diameter with a ruler, and multiply the magnification to calculate the primary particle size. Let the average value of these values be a particle diameter.
(2) Volume resistivity of metal thin film Measured using a low resistivity meter “Loresta (registered trademark)” GP (manufactured by Mitsubishi Chemical Corporation).

(3) Tape peel test and adhesive strength measurement (180 degree peel test)
The tape peel test is based on whether or not the metal thin film adheres to the scotch tape and is peeled off from the substrate when the scotch tape (registered trademark, manufactured by Sumitomo 3M Limited) is applied to the obtained metal thin film. To do.
A sample for measuring the adhesive strength is prepared as follows. A metal film is thickened on the obtained metal thin film by electroplating to make the total thickness of the metal portion about 15 μm, and then a slit having a width of 3 mm and a length of 50 mm is made with a cutter knife. In the 180 degree peel test, one side of a 3 mm width side is peeled off slightly and an aluminum tape is applied, this tape part is fixed to a peel tester, pulled up in the 180 degree direction, and the force required for peeling is measured. Adhesive strength (kN / m).

(4) Observation of the metal thin film and the interface form between the metal thin film and the insulating resin layer The form of the metal thin film is a cross-sectional TEM image of the laminate using a transmission electron microscope (JEM-4000FX) manufactured by Hitachi, Ltd. Observe. The surface roughness of the contact interface between the metal thin film layer and the insulating resin layer is observed as follows. The cross-sectional TEM image of the interface portion is digitized with a scanner, and an 8-bit grayscale image of the metal thin film interface obtained by fusing is acquired. After binarization, edge extraction is performed to obtain an interface profile image (line image) of the metal thin film. Further, the surface roughness (Ra) of the contact interface between the metal thin film layer and the insulating resin layer is estimated using the amount of displacement of the line image from the straight line connecting both ends of the image profile image to the insulating resin layer side.

(5) X-ray analysis of a metal thin film X-ray analysis of a metal thin film is measured using a Rigaku X-ray diffraction apparatus (Rint-2500). The excitation voltage / current was 40 kV, 200 mA, the scan speed was 2 deg / min, the scan step was 0.02 deg, and the range of 25 to 80 deg was measured.
(6) Chemical resistance After a metal film was thickened by electroplating on the alloy thin film and the total thickness of the metal part was about 5 μm, a comb-shaped electrode of line / space = 20 μm / 20 μm was prepared by photolithography, The copper wiring is immersed in an electroless tin plating solution containing 50 g / l of SnCl ₂ · 2H ₂ O, 50 ml / l of HCl, and 100 g / l of thiourea at 65 ° C. for 5 minutes, and from the back side of the sample through the resin layer Judgment is made by whether or not there is discoloration or the like at the end of the metal thin film observed with a 500 × optical microscope.

[Example 1]
(Synthesis of thermoplastic polyimide solution)
The ratio of 1.0 mole of 2,2′-bis (4- (4-aminophenoxy) phenylpropane to 1.0 mole of 3,3 ′, 4,4′-biphenylsulfonetetracarboxylic dianhydride Weighed and added NMP to a solid content concentration of 10 wt%, and stirred and dissolved at 50 ° C. for 10 hours to obtain a polyamic acid solution as a thermoplastic polyimide precursor, which had a glass transition temperature of 260. ° C.

(Preparation of substrate having thermoplastic polyimide layer)
A polyimide film cut out into a 20 × 30 cm square (Kapton film manufactured by Toray DuPont Co., Ltd., film thickness 50 μm) is set on a bar coater, coated with a bar coat so that the film thickness becomes 30 μm, and then heated at 90 ° C. on a hot plate. 10 minutes, 120 ° C. × 10 minutes, 150 ° C. × 10 minutes, 180 ° C. × 10 minutes, 250 ° C. × 60 minutes, 300 ° C. × 60 minutes to obtain a polyimide substrate having a thermoplastic polyimide resin on the surface It was.

(Formation of metal thin film)
The polyimide substrate was set in a vacuum deposition apparatus, the system was evacuated, and Cu—Ni (1: 1) was deposited to obtain a 0.3 μm CuNi alloy thin film. The peak position derived from the metal near 43 ° measured by X-ray analysis was 43.95 °, which was higher than the peak of Cu alone, 43.305 °.

(Heat treatment)
The substrate having the alloy thin film was heat-treated at 350 ° C. for 10 minutes in a nitrogen atmosphere adjusted to an oxygen concentration of 200 ppm.

(Plating layer application, adhesive strength measurement, peeling interface analysis)
80 g of copper sulfate pentahydrate (Wako Pure Chemical Industries, Ltd.) and 180 g of sulfuric acid were dissolved in 1 liter of purified water to prepare an electrolytic plating bath. The surface of the alloy film obtained above is degreased and pickled, and then immersed in a plating bath and subjected to electrolytic copper plating at a current density of 3 A / dm ² at room temperature, and the total thickness of the metal layer (alloy thin film layer + A laminated substrate having a copper film formed by plating of 15 μm was completed. The adhesive strength according to the 180 degree peel test was as high as 0.80 kN / m. With respect to the peeling interface between the alloy thin film layer and the polyimide layer, XPS analysis of the copper interface confirmed the presence of cuprous oxide and nickel oxide. The Ra at the interface was 3 nm.

(Electroless tin plating)
Electrolytic tin plating treatment was performed on the line / space = 20 μm / 20 μm comb-shaped electrode, and the end of the wiring was observed from the back side, but no discoloration or the like was observed.

[Example 2]
(Formation of metal thin film)
The polyimide substrate produced by the same method as in Example 1 was set in a vacuum deposition apparatus, the system was evacuated, and Cu—Ni (4: 1) was deposited to obtain a 0.3 μm alloy thin film. . The peak position derived from the metal near 43 ° measured by X-ray analysis was 43.37 °, which was higher than the peak 43.305 ° of Cu alone.
(Heat treatment)
The substrate having the alloy thin film was heat-treated at 350 ° C. for 10 minutes in a nitrogen atmosphere adjusted to an oxygen concentration of 200 ppm.
(Plating layer application, adhesion strength measurement, peeling interface analysis)
An electrolytic copper plating process was performed in the same manner as in Example 1 to complete a 15 μm laminated substrate. The adhesive strength according to the 180 degree peel test was as high as 0.9 kN / m. With respect to the peeling interface between the alloy thin film layer and the polyimide layer, XPS analysis of the copper interface confirmed the presence of cuprous oxide and nickel oxide. The Ra at the interface was 3 nm.
(Electroless plating treatment)
Electrolytic tin plating treatment was performed on the line / space = 20 μm / 20 μm comb-shaped electrode, and the end of the wiring was observed from the back side, but no discoloration or the like was observed.

[Example 3]
(Formation of metal thin film)
A polyimide substrate produced by the same method as in Example 1 was set in a vacuum deposition apparatus, the system was evacuated, and Cu—Ni (1: 2) was deposited to obtain a 0.3 μm CuNi alloy thin film. It was. The peak position derived from the metal near 43 ° measured by X-ray analysis was 44.7 °. The peak was higher than the peak of 43.305 ° of Cu alone.
(Heat treatment)
The substrate having the alloy thin film was heat-treated at 350 ° C. for 10 minutes in a nitrogen atmosphere adjusted to an oxygen concentration of 200 ppm.
(Plating layer application, adhesion strength measurement, peeling interface analysis)
An electrolytic copper plating process was performed in the same manner as in Example 1 to complete a 15 μm laminated substrate. The adhesive strength according to the 180 degree peel test was as high as 0.7 kN / m. With respect to the peeling interface between the alloy thin film layer and the polyimide layer, XPS analysis of the copper interface confirmed the presence of cuprous oxide and nickel oxide. The Ra at the interface was 2 nm.
(Electroless tin plating)
Electrolytic tin plating treatment was performed on the line / space = 20 μm / 20 μm comb-shaped electrode, and the end of the wiring was observed from the back side, but no discoloration or the like was observed.

[Example 4]
(Formation of metal thin film)
A polyimide substrate produced by the same method as in Example 1 was set in a vacuum deposition apparatus, the system was evacuated, and Cu—Sn (95: 5) was deposited to obtain a 0.3 μm alloy thin film. . The peak position derived from the metal near 43 ° measured by X-ray analysis was 42.70 °, which was a lower angle side than the peak 43.305 ° of Cu alone.
(Heat treatment)
The substrate having the alloy thin film was heat-treated at 350 ° C. for 10 minutes in a nitrogen atmosphere adjusted to an oxygen concentration of 300 ppm.
(Plating layer application, adhesion strength measurement, peeling interface analysis)
An electrolytic copper plating process was performed in the same manner as in Example 1 to complete a 15 μm laminated substrate. The adhesive strength according to the 180 degree peel test was as high as 0.8 kN / m. As for the peeling interface between the alloy thin film layer and the polyimide layer, the presence of cuprous oxide and tin oxide was confirmed by XPS analysis of the copper interface. The Ra at the interface was 3 nm.
(Electroless plating treatment)
An electroless tin plating treatment was applied to a comb-shaped electrode of line / space = 20 μm / 20 μm, and the wiring end portion was observed from the back side. The discoloration width of the end portion was 1 μm or less.

[Example 5]
(Preparation of metal thin film precursor fine particles and dispersion)
70 ml of purified water was added to 8 g of anhydrous copper acetate (manufactured by Wako Pure Chemical Industries, Ltd.). While stirring at 25 ° C., 2.6 ml of 64% by weight hydrazine hydrate was added and reacted so that the molar ratio of hydrazine to copper acetate was 1.2 to obtain cuprous oxide fine particles having a particle size of 20 nm. . 2 g of polyethylene glycol methyl ether (number average molecular weight 350, manufactured by Aldrich) and 7 g of diethylene glycol were added to 3 g of the obtained cuprous oxide, and ultrasonic dispersion was performed to obtain a cuprous oxide dispersion. Furthermore, nickel fine particles (manufactured by Aldrich) having a particle diameter of 90 nm were added to the cuprous oxide dispersion in an amount of 10 wt% with respect to the cuprous oxide, and ultrasonic dispersion was performed to obtain a metal thin film precursor dispersion.

(Formation of metal thin film)
A polyimide substrate produced in the same manner as in Example 1 was set on a bar coater, and the above-mentioned dispersion was dropped, followed by application to a film thickness of 20 μm. Next, this coating film is put in an electric furnace and baked at a temperature higher than the glass transition temperature (260 ° C.) of the polyimide film under the condition of 100% hydrogen and 350 ° C. × 30 minutes. A substrate having a Cu—Ni alloy thin film having a thickness of 1 μm and a volume resistivity of 4 × 10 ⁻⁶ Ωcm was obtained. The peak position derived from the metal near 43 ° measured by X-ray analysis was 43.36 °, which was higher than the peak of Cu alone, 43.305 °.

(Heat treatment)
The substrate having the copper thin film was subjected to heat treatment at 350 ° C. for 10 minutes in a nitrogen atmosphere adjusted to an oxygen concentration of 80 ppm.
(Plating layer application, adhesive strength measurement, peeling interface analysis)
The same electrolytic copper plating as in Example 1 was performed to complete a laminated substrate having a total metal layer thickness (copper thin film layer + copper film formed by plating) of 15 μm. The adhesive strength according to the 180 degree peel test was as extremely high as 1.4 kN / m. Regarding the peeling interface between the copper layer and the polyimide layer, the presence of cuprous oxide and nickel oxide was confirmed by XPS analysis of the copper interface. When the interface morphology analysis was performed, a part of the metal thin film layer was embedded and adhered in the thermoplastic polyimide layer, the depth was 10 to 30 nm, and Ra was 10 nm.

(Electroless tin plating)
Electrolytic tin plating treatment was applied to the line / space = 20 μm / 20 μm comb-shaped electrode, and the end of the wiring was observed from the back side, but the discoloration was 1 μm or less.
(Characteristics of printed wiring board)
When a comb-shaped electrode of line / space = 20 μm / 20 μm was produced on the laminated substrate obtained above by photolithography, it was confirmed that the linearity of the wiring was extremely high and the fine wiring formation was high. Moreover, the disconnection of the wiring considered to be caused by the pinhole was not observed. The migration test was performed on the fabricated comb-shaped electrode under the conditions of temperature 85 ° C. × humidity 85% and applied voltage 50 V. Even after 500 hours, the insulation between the wirings was maintained at a level of 10 ¹² Ω. No decrease in insulation was observed.

[Comparative Example 1]
A sample prepared by using the sputtering target of Example 1 as copper was processed in the same manner to obtain a 0.3 μm copper thin film.
(Formation of metal thin film)
A polyimide substrate produced by the same method as in Example 1 was set in a vacuum deposition apparatus, the system was evacuated, and Cu was deposited to obtain a 0.3 μm alloy thin film. The peak position derived from the metal near 43 ° measured by X-ray analysis was 43.305 °.
(Heat treatment)
The substrate having the copper thin film was heat-treated at 350 ° C. for 10 minutes in a nitrogen atmosphere adjusted to an oxygen concentration of 200 ppm.
(Plating layer application, adhesion strength measurement, peeling interface analysis)
An electrolytic copper plating process was performed in the same manner as in Example 1 to complete a 15 μm laminated substrate. The adhesive strength according to the 180 degree peel test was as extremely high as 1.0 kN / m. Regarding the peeling interface between the copper layer and the polyimide layer, XPS analysis of the copper interface confirmed the presence of cuprous oxide. The Ra at the interface was 1 nm.
(Electroless tin plating)
When the electroless tin plating treatment was applied to the comb-shaped electrode of line / space = 20 μm / 20 μm, both ends of the wiring were dissolved over a width of 5 μm.

The laminate of the present invention has high conductivity equivalent to that of a conventional metal thin film and extremely high adhesion between the metal thin film and the substrate. Further, since the thickness of the metal film can be arbitrarily controlled and a thin metal film can be easily formed, it can be used particularly suitably as a flexible circuit board material. Since the roughness of the interface between the insulating resin and the metal layer is as low as about several tens of nanometers, the laminate of this embodiment can form fine pitch wiring with high wiring linearity.
In addition, on the insulating substrate on which the insulating resin layer and / or the insulating resin precursor layer is formed, the wiring pattern shape is directly drawn by an inkjet method or the like using the metal thin film precursor fine particle dispersion, and this is subjected to heat treatment. By doing so, it is possible to form a metal wiring with high adhesiveness. Therefore, it can be used not only for circuit formation of a printed wiring board but also for manufacturing bus electrodes and address electrodes formed on a glass substrate in manufacturing flat panel displays such as plasma display panels and liquid crystal panels.

Claims (23)

  A laminated body including an insulating resin layer and a metal thin film layer formed on the insulating resin layer, wherein the metal thin film layer is an alloy layer composed of two or more kinds of metals, and the insulating property A laminate comprising a metal oxide at a contact interface between a resin layer and the metal thin film layer.   The laminate according to claim 1, wherein the metal thin film layer includes Cu. The metal-derived peak position near 43 ° measured by X-ray analysis of the metal thin film layer is in the range of 42.5 ° to 45.0 ° excluding the peak position 43.305 ° of Cu (100). The laminate according to claim 1, wherein the laminate is provided.   The laminate according to any one of claims 1 to 3, wherein the metal thin film layer includes at least one selected from Sn, Ni, Co, Mn, Zn, and Cr.   The laminate according to any one of claims 1 to 4, wherein the metal oxide includes copper oxide and another metal oxide different from copper oxide.   The laminate according to any one of claims 1 to 5, wherein the metal thin film layer comprises a metal thin film layer including a structure in which metal particles are fused to each other.   The laminate according to any one of claims 1 to 6, wherein the surface roughness of the contact interface between the insulating resin layer and the metal thin film layer is in the range of 2 to 100 nm. The laminate according to any one of claims 1 to 7, further comprising a metal plating layer on the metal thin film layer. The laminate according to claim 1, wherein the insulating resin layer is a thermoplastic insulating resin layer having an imide bond and / or an amide bond. The laminated body according to claim 9, wherein the insulating resin layer includes a thermoplastic polyimide resin.   A step (1) of forming an insulating resin layer, a step (2) of forming an alloy layer composed of two or more metals on the insulating resin layer, the metal thin film layer and the insulating resin. And a step (3) of forming the metal oxide at the interface with the layer.   The method for producing a laminate according to claim 11, wherein in the step (3) of forming the metal oxide, heat treatment is performed in an atmosphere containing an oxidizing agent.   13. The laminate according to claim 12, wherein the step (3) of forming the metal oxide performs heat treatment at a temperature equal to or higher than a glass transition temperature of the insulating resin layer in an inert atmosphere containing 20 ppm to 2000 ppm of oxygen. Body manufacturing method.   The method for manufacturing a laminate according to any one of claims 11 to 13, wherein the step (2) of forming the metal thin film comprises a dry plating method. The method for manufacturing a laminate according to any one of claims 11 to 13, wherein the step (2) of forming the metal thin film comprises a wet plating method.   The step (2) of forming the metal thin film comprises a method of applying a dispersion or a solution containing two or more kinds of metal thin film precursors and performing a heat treatment in a non-oxidizing atmosphere. The manufacturing method of the laminated body in any one of 11-13.   The step (2) of forming the metal thin film comprises a method of applying a dispersion or a solution containing two or more kinds of metal thin film precursors and performing a heat treatment in a reducing atmosphere. The manufacturing method of the laminated body as described in any one of.   In the step (2) of forming the metal thin film, the coating film is dried after the dispersion or solution containing two or more metal thin film precursors is applied and before the heat treatment. The manufacturing method of the laminated body of Claim 16 or 17.   The laminate according to any one of claims 16 to 18, wherein the metal thin film precursor includes at least one selected from the group consisting of metal fine particles, metal oxide fine particles, metal hydroxides, metal complexes, and metal salts. Production method.   The manufacturing method of the laminated body in any one of Claims 16-19 in which the said metal thin film precursor contains cuprous oxide microparticles | fine-particles.   The manufacturing method of the laminated body in any one of Claims 16-20 in which the said dispersion contains a polyhydric alcohol and / or a linear aliphatic polyether compound.   It manufactures with the manufacturing method in any one of Claims 11-21, The manufacturing method of the laminated body in any one of Claims 1-10 characterized by the above-mentioned.   The printed wiring board made using the laminated body in any one of Claims 1-10.