Laminate

Abstract

A laminate comprising a substrate and a plating formation layer disposed on at least one of both surfaces of the substrate and containing a thermoplastic resin and a plating catalyst, wherein the plating formation layer further satisfies the following conditions (1) and / or (2): (1) The plating layer contains a dispersant that disperses the plating catalyst. (2) The amount of the plating catalyst present on the surface side of the plating formation layer is greater than the amount of the plating catalyst present on the substrate side of the plating formation layer.

Description

[Technical Field]

[0001] This invention relates to a laminate. [Background technology]

[0002] In recent years, with the increasing integration of semiconductor circuits, there has been a growing demand to form even finer wiring circuits on printed circuit boards. To form finer wiring circuits, the thickness of the wiring needs to be reduced. However, even thin metal foil has a thickness of 2 μm, which is insufficient for forming fine circuits and leads to a problem of reduced productivity.

[0003] To address these problems, Patent Document 1 discloses that a laminate in which a polymer film, a plating layer containing a crystalline thermoplastic resin, and a plating layer are laminated in this order is a material capable of forming microcircuits, and furthermore, the adhesion between the plating layer and the plating layer and the solder heat resistance can be improved. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] WO2009075212 Brochure [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, there is a need to further improve the laminate described in Patent Document 1 by balancing its adhesive properties under normal conditions with its solder heat resistance.

[0006] Therefore, the present invention aims to provide a laminate that can improve both adhesion under normal conditions and solder heat resistance in a well-balanced manner. [Means for solving the problem]

[0007] As a result of diligent research to solve the above problems, the present inventors have found that the above problems can be solved by having a laminate comprising a substrate and a plating-forming layer disposed on at least one of the two surfaces of the substrate and containing a thermoplastic resin and a plating catalyst, provided that the plating-forming layer satisfies specific conditions, and have completed the present invention.

[0008] In other words, the present invention is as follows. [1] Substrate and A plating layer containing a thermoplastic resin and a plating catalyst is disposed on at least one of both sides of the substrate, A laminate containing, The aforementioned plating layer is a laminate that further satisfies the following conditions (1) and / or (2). (1) The plating layer contains a dispersant that disperses the plating catalyst. (2) The amount of the plating catalyst present on the surface side of the plating layer is greater than the amount of the plating catalyst present on the substrate side of the plating layer. [2] A laminate of [1] in which the dispersant is a compound that interacts with and bonds with metal atoms contained in the plating catalyst. [3] A laminate of [2] in which the terminal group of the compound is a functional group containing a nitrogen atom. [4] The plating-forming layer is a laminate of any one of [1] to [3] comprising a resin layer containing the thermoplastic resin and a catalyst layer disposed on the resin layer and containing the plating catalyst. [5] The laminate of [4], wherein the catalyst layer contains the dispersant. [6] The laminate of [4] or [5] further comprises a boundary layer in which the plating forming layer is disposed between the resin layer and the catalyst layer and the plating catalyst and the dispersant are impregnated into the thermoplastic resin. [7] The substrate is a laminate of any of [1] to [6], wherein the substrate is a thermosetting polyimide resin. [8] The laminate according to any one of [1] to [7], wherein the thermoplastic resin is a thermoplastic polyimide resin. [9] The laminate according to any one of [1] to [8], wherein the plating catalyst contains palladium and / or silver.

[10] The laminate according to any one of [1] to [9], further including a metal plating layer disposed on the plating formation layer. [Advantages of the Invention]

[0009] According to the present invention, it is possible to provide a laminate in which the adhesiveness in a normal state and the solder heat resistance are further improved in a well-balanced manner. [Brief Description of the Drawings]

[0010] [Figure 1] FIG. 1 shows a cross-sectional view of a laminate observed using a scanning electron microscope in Example 1. [Modes for Carrying Out the Invention]

[0011] Hereinafter, modes for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. Note that the present invention is not limited to the following embodiments, and various modifications can be made and implemented within the scope of the gist thereof.

[0012] [Laminate] The laminate of the present embodiment includes a base material and a plating formation layer disposed on at least one of both surfaces of the base material and containing a thermoplastic resin and a plating catalyst. The plating formation layer further satisfies the following condition (1) and / or (2). (1) The plating formation layer contains a dispersant for dispersing the plating catalyst. (2) The abundance (C a ) of the plating catalyst on the surface side of the plating formation layer is greater than the abundance (C b ) of the plating catalyst on the base material side of the plating formation layer. By satisfying the above conditions (1) and / or (2), the laminate containing the plating layer can achieve a good balance between normal adhesion and solder heat resistance, resulting in, for example, excellent adhesion with long-term reliability in mind. Here, adhesion with long-term reliability in mind refers to the property that, for example, the deterioration of adhesion is sufficiently suppressed even after heat treatment at 150°C.

[0013] The following factors are thought to contribute to the improved adhesion under normal conditions, adhesion for long-term reliability, and solder heat resistance of the laminate when the plating layer satisfies conditions (1) and / or (2). Laminates used in printed circuit board materials and the like consist of a substrate, a plating layer formed on one side of the substrate and containing a thermoplastic resin and a plating catalyst, and a metal plating layer formed on the plating layer. The reason why the adhesion (adhesion under normal conditions and adhesion assuming long-term reliability) and solder heat resistance of such laminates is insufficient is thought to be due to the small amount of metal (catalyst metal) contained in the plating catalyst near the interface between the plating layer and the metal plating layer. To increase the amount of catalyst metal near the interface, a dispersant for dispersing the plating catalyst is included in the plating layer, or the amount of plating catalyst in the plating layer is controlled. This increases the proportion of contact between the plating metal and the catalyst metal. As a result, the catalyst metal and the plating metal come into contact more easily, and the adhesion (adhesion under normal conditions and adhesion assuming long-term reliability) and solder heat resistance of the laminate are thought to improve. However, the factors are not limited to these.

[0014] (base material) The resin used as the substrate is not particularly limited, and examples include thermosetting polyimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polybutylene terephthalate, polyetheretherketone, polyethersulfone, polyphenylene ether, and fluororesins. These resins can be used individually or in combination of two or more. Among these, thermosetting polyimide resin is preferred from the viewpoint of superior mechanical properties, thermal properties, and dimensional stability during heating. Furthermore, in flexible printed circuit boards that transmit high-frequency signals, liquid crystal polymer or fluororesin is preferred as the resin from the viewpoint of dielectric properties. Since liquid crystal polymer and fluororesin have low water absorption rates, they also exhibit good resistance to humid and heat conditions, dimensional stability under high humidity, and peel strength after moisture absorption treatment.

[0015] (Thermosetting polyimide resin) A thermosetting polyimide resin is, for example, a polyimide resin that maintains an elastic modulus at 300°C of 20% or more compared to the elastic modulus at 30°C. The elastic modulus can be determined, for example, by the DMA (dynamic viscoelasticity measurement) method. While there are no particular limitations on thermosetting polyimide resins, examples include condensation-type polyimide resins obtained by copolymerizing acid dianhydrides and diamines, bismaleimide resins, and maleimide resins.

[0016] As the acidic dianhydride and diamine, for example, any of aliphatic compounds, alicyclic compounds, or aromatic compounds can be used. From the viewpoint of heat resistance, aromatic tetracarboxylic dianhydride is preferred as the acidic dianhydride, and aromatic diamine is preferred as the diamine.

[0017] Examples of acid dianhydrides include pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 4,4'-oxydiphthalic acid dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, and bis(3,4-dicarboxyphenyl)propane dianhydride. Examples include boxyphenyl)propane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, p-phenylenebis(trimellitic acid monoester anhydride), ethylenebis(trimellitic acid monoester anhydride), and bisphenol A bis(trimellitic acid monoester anhydride). These acid dianhydrides can be used individually or in combination of two or more. Among these, at least one acid dianhydride selected from the group consisting of pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, and 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride is preferred from the viewpoint of heat resistance and dimensional stability.

[0018] Examples of diamines include 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylmethane, benzidine, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 4,4'-oxydianiline, 3,3'-oxydianiline, 3,4'-oxydianiline, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 4,4'-diaminodiphenyldiethylsilane, 4,4'-diaminodiphenylsilane, 4,4'-diaminodiphenylethylphosphine oxide, 4,4'-diamino Examples include diphenyl N-methylamine, 4,4'-diaminodiphenyl N-phenylamine, 1,4-diaminobenzene (p-phenylenediamine), 1,3-diaminobenzene, 1,2-diaminobenzene, bis{4-(4-aminophenoxy)phenyl}sulfone, bis{4-(3-aminophenoxy)phenyl}sulfone, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, and 2,2-bis[4-(4-aminophenoxy)phenyl)]propane. These diamines can be used individually or in combination of two or more. Among these, it is preferable to contain at least one diamine selected from the group consisting of 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 1,5-diaminonaphthalene, and 1,4-diaminobenzene (p-phenylenediamine), from the viewpoint of heat resistance and dimensional stability.

[0019] The base material may or may not contain components other than resin, as long as they do not hinder the effects of the present invention.

[0020] The substrate is preferably a resin film, and more preferably a thermosetting polyimide resin film. The thermosetting polyimide resin film may be a prepared product made by a known method, or a commercially available product. Examples of commercially available products include Toray DuPont's "Kapton EN series," "Kapton H series," and "Kapton V series," Kaneka Corporation's "Apical HP series" and "Apical NPI series," and Ube Industries, Ltd.'s "UPIREX S."

[0021] The thickness of the substrate in the lamination direction is preferably 5 μm to 500 μm from the viewpoint of transportability, insulation, and heat resistance. From the same viewpoint, the thickness is more preferably 7.5 μm to 300 μm, and even more preferably 10 μm to 100 μm.

[0022] (Plating layer) The plating layer may be placed on one of the two surfaces of the substrate, or it may be placed on both surfaces of the substrate. The plating layer comprises a thermoplastic resin and a plating catalyst.

[0023] (thermoplastic resin) A thermoplastic resin is, for example, a resin that has a softening point temperature, meaning it softens when heated above its glass transition temperature (hereinafter also referred to as Tg). Thermoplastic resins may be in an uncured or cured state. Examples of thermoplastic resins include thermoplastic polyimide resins, aromatic polyether ketones, polyphenylene sulfide, polyethylene, polypropylene, polybutene, crystalline polybutadiene, polymethylpentene, polyamide, polyester, polyurethane, liquid crystal polymer, and polystyrene. These thermoplastic resins may be used individually or in combination of two or more. Among these, thermoplastic polyimide resins are preferred from the viewpoint of further improving solder heat resistance. A thermoplastic polyimide resin is, for example, a polyimide resin whose modulus of elasticity at 300°C is less than 20% of its modulus of elasticity at 30°C.

[0024] In the laminate of this embodiment, it is preferable that the substrate is a thermosetting polyimide resin and the thermoplastic resin contained in the plating layer is a thermoplastic polyimide resin. This tends to further improve the adhesion between the substrate and the plating layer.

[0025] Examples of thermoplastic polyimide resins include polyimide resins obtained by copolymerizing an acidic dianhydride and a diamine. Examples of acidic dianhydride and diamine include those used in the thermosetting polyimide resins described above.

[0026] The content of thermoplastic resin relative to the entire plating layer is, for example, 1% to 99% by mass, preferably 20% to 95% by mass, and more preferably 40% to 90% by mass.

[0027] (Plating catalyst) The plating catalyst contains a precious metal. Any catalyst commonly used in plating processes (e.g., electroless plating) can be used as the plating catalyst. Examples of precious metals include palladium, silver, platinum, nickel, gold, and their alloys. These precious metals may exist in the plating layer in ionic form. These precious metals may be used individually or in combination of two or more. Among these, palladium and / or silver are preferred. By using such precious metals, when forming a metal plating layer (e.g., a copper plating layer) on the plating layer, the thickness of the metal plating layer can be reduced, which tends to allow for the formation of finer circuits.

[0028] From the viewpoint of uniformly depositing the plating layer on the surface of the adhesive layer, it is desirable that the plating catalyst contains the noble metal in colloidal or uniformly dispersed form in the solvent. The solvent is not particularly limited and includes those commonly used to disperse noble metal particles, such as water, methanol, ethanol, isopropyl alcohol and other alcohols, hexane, cyclohexanone, methyl ethyl ketone, acetone, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, toluene, diethyl ether, tetrahydrofuran (THF), and mixtures thereof.

[0029] The average particle size (D50) of the precious metal particles may be, for example, around 2 nm to 40 nm. The average particle size is the volume-based average particle size and can be determined, for example, by a particle size distribution analyzer using dynamic light scattering (DLS). Note that D50 refers to the position where the volume accumulation reaches 50%. When the average particle size (D50) of the precious metal particles is 40 nm or less, the surface area of ​​the precious metal increases, and the catalytic activity rises. This tends to improve the reactivity of the plating.

[0030] The content of the plating catalyst relative to the entire plating layer is, for example, 1% to 99% by mass, preferably 5% to 80% by mass, and more preferably 10% to 60% by mass.

[0031] (Dispersant) The plating layer contains a dispersant for dispersing the plating catalyst. However, the plating layer is defined as "(2) Amount of plating catalyst present on the surface side of the plating layer (C a ) is the amount of the plating catalyst present on the substrate side of the plating forming layer (C bIf the condition of "greater than " is satisfied, the dispersant is not necessarily essential. The dispersant is preferably a compound that interacts and binds with the metal atoms (catalyst metals) contained in the plating catalyst, and it is more preferable that the terminal group of the compound is a functional group containing a nitrogen atom or the compound has an unsaturated bond. The bonding form may be, for example, a coordination bond, an ionic bond, a covalent bond, or the like. By using such a dispersant, the catalyst metal is uniformly dispersed in the plating formation layer. And due to this dispersion, the ratio of contact between the catalyst metal and the plating metal becomes even larger, so the precipitation property of the plating metal is improved. As a result, the generation of pinholes in the plating formation layer is greatly reduced.

[0032] The content of the dispersant in the entire plating formation layer is, for example, 1% by mass to 99% by mass, preferably 10% by mass to 80% by mass, and more preferably 20% by mass to 60% by mass.

[0033] Let the abundance of the plating catalyst on the surface side of the plating formation layer be C a and the abundance of the plating catalyst on the substrate side of the plating formation layer be C b When used, the plating formation layer satisfies C a > C b However, when the plating formation layer satisfies the condition of (1) above, it is not necessarily required to satisfy C a > C b C a and C b are determined using an X-ray photoelectron spectrometer. That is, when the noble metal contained in the plating catalyst is palladium (Pd), the abundance of the catalyst on the surface side of the plating formation layer (palladium abundance (Pd abundance)) is measured from the surface side using an X-ray photoelectron spectrometer and obtained from the detected atomic% concentration of Pd. Specifically, the value obtained by dividing the atomic% concentration of palladium (Pd) by the atomic% concentration of carbon (C) is the abundance of the catalyst (palladium abundance (Pd abundance)) C aThe amount of catalyst present on the substrate side of the plating layer is determined by treating the surface side of the plating layer with argon ions, and after treating up to a predetermined location, using an X-ray photoelectron spectroscopy analyzer in the same manner as above to determine the amount of plating catalyst present on the substrate side of the plating layer (palladium present (Pd present)) C b We seek.

[0034] This increases the proportion of the plated metal in contact with the catalyst metal. As a result, the catalyst metal and the plated metal come into contact more easily, which is expected to improve the adhesion of the laminate (adhesion under normal conditions and adhesion assuming long-term reliability) and the solder heat resistance.

[0035] C a >C b Means of satisfying this condition include, for example, forming a resin layer containing a thermoplastic resin on a substrate and laminating a catalyst layer containing the above-mentioned dispersant on the resin layer.

[0036] The thickness of the plating layer is, for example, 10 nm to 10 μm, and from the viewpoint of more effectively and reliably achieving the effects of the present invention, it is preferably 30 nm to 8 μm, and more preferably 50 nm to 6 μm.

[0037] The plating layer may have a single-layer structure or a multilayer structure. When the plating layer has a multilayer structure, from the viewpoint of further improving adhesion and solder heat resistance, the multilayer structure preferably includes a resin layer containing a thermoplastic resin and a catalyst layer containing a plating catalyst, and the catalyst layer preferably further contains the above-mentioned dispersant. When the plating layer has the above-mentioned multilayer structure, for example, a resin layer is arranged (formed) on a substrate, and a catalyst layer is arranged (formed) on the resin layer.

[0038] (Resin layer) Examples of thermoplastic resins included in the resin layer include those similar to those used in the plating layer described above.

[0039] The thickness of the resin layer is, for example, 10 nm to 10 μm, and from the viewpoint of more effectively and reliably achieving the effects of the present invention, it is preferably 30 nm to 8 μm, and more preferably 50 nm to 6 μm.

[0040] (catalyst layer) The plating catalyst and dispersant included in the catalyst layer are the plating catalyst and dispersant exemplified in the section on the plating formation layer, respectively.

[0041] The thickness of the catalyst layer is, for example, 5 nm to 300 nm, and from the viewpoint of more effectively and reliably achieving the effects of the present invention, it is preferably 10 nm to 200 nm, and more preferably 20 nm to 100 nm.

[0042] The multilayer structure may consist only of a resin layer and a catalyst layer, or it may consist of a resin layer, a catalyst layer, and one or more other layers other than the resin layer and the catalyst layer.

[0043] Among these, the plating layer preferably further comprises a resin layer, a catalyst layer, and a boundary layer disposed between the resin layer and the catalyst layer. The boundary layer is formed, for example, by the penetration of a plating catalyst and a dispersant into the surface layer of the resin layer. Including such a boundary layer improves the interlayer adhesion between the resin layer and the catalyst layer, and as a result, tends to result in even greater peel strength.

[0044] The thickness of the boundary layer is, for example, 0.5 nm to 300 nm, and from the viewpoint of more effectively and reliably achieving the effects of the present invention, it is preferably 1 nm to 200 nm, and more preferably 2 nm to 100 nm.

[0045] The laminate of this embodiment may or may not include a plating layer disposed on a plating surface.

[0046] (Plating layer) Examples of plating layers include metal plating layers formed by metal plating treatment, and examples of metal plating layers include copper plating layers, gold plating layers, tin plating layers, nickel plating layers, silver plating layers, palladium plating layers, solder plating layers, and lead-free solder plating layers.

[0047] From the viewpoint of more effectively and reliably achieving the effects of the present invention, the thickness of the plating layer is preferably 0.05 μm to 35 μm, more preferably 0.1 μm to 18 μm, and even more preferably 0.1 μm to 12 μm.

[0048] The laminate of this embodiment may have a configuration in which a plating layer and a plating layer are laminated in this order on one side of the substrate, or it may have a configuration in which a plating layer and a plating layer are laminated in this order on both sides of the substrate. When the laminate of this embodiment has a configuration in which a plating layer and a plating layer are laminated in this order on both sides of the substrate, the plating layer has, for example, a first plating layer formed on one side of the substrate and a second plating layer formed on the other side of the substrate, and the plating layer has a first plating layer formed on the surface of the first plating layer and a second plating layer formed on the surface of the second plating layer. The first plating layer and the second plating layer may be the same or different.

[0049] (characteristic) The laminate of this embodiment exhibits excellent adhesion under normal conditions, and its peel strength in 90-degree direction peeling is, for example, 5.0 N / cm or more (e.g., 5.0 N / cm to 8.0 N / cm), preferably 6.0 N / cm or more, and more preferably 6.5 N / cm or more.

[0050] Furthermore, the laminate of this embodiment exhibits excellent adhesion, assuming long-term reliability. For this reason, the peel strength after being placed in a dryer at 150°C for 240 hours is, for example, 5.0 N / cm or more (e.g., 5.0 N / cm to 8.0 N / cm) in the 90-degree peel direction, preferably 6.0 N / cm or more, and more preferably 6.5 N / cm or more. Also, the peel strength after being placed in a constant temperature and humidity chamber at 85°C and 85% humidity for 240 hours is, for example, 5.0 N / cm or more (e.g., 5.0 N / cm to 8.0 N / cm) in the 90-degree peel direction, preferably 6.0 N / cm or more, and more preferably 6.5 N / cm or more.

[0051] (Application) The laminate of this embodiment is suitably used as a material for flexible printed circuit boards where the formation of fine wiring circuits is required. Flexible printed circuit boards are suitably used, for example, as so-called chip-on flexible printed circuit boards for IC chip mounting, and as flexible printed circuit boards for high-density circuit formation.

[0052] [Method for manufacturing laminates] The manufacturing method of the laminate according to this embodiment may further include a plating layer formation step of forming a plating layer by applying a thermoplastic resin and, if necessary, a plating catalyst raw material containing the above-mentioned dispersant to at least one surface of a substrate and drying it, and a plating layer formation step of forming a plating layer by performing a plating treatment on the surface of the plating layer opposite to the substrate. The manufacturing method according to this embodiment tends to improve the adhesion and solder heat resistance of the resulting laminate under normal conditions by having the above configuration.

[0053] (Plating layer formation process) The plating layer formation process involves applying a thermoplastic resin and a plating catalyst raw material onto a substrate and drying them to form a plating layer.

[0054] The substrate is not particularly limited; for example, those exemplified as substrates in the section on laminates can be cited.

[0055] The thermoplastic resin is not particularly limited, and examples include those exemplified as thermoplastic resins in the section on laminates. In the plating layer formation process, for example, the thermoplastic resin is used in a form dissolved or dispersed in an organic solvent. The organic solvent is not particularly limited as long as it is a solvent capable of dissolving or dispersing the thermoplastic resin, and examples include alcohols (e.g., methanol, ethanol, propanol, butanol, pentanol, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, trimethylolethane, and trimethylolpropane), ethers (e.g., alkyl ethers such as butyl ethyl ether, polyhydric alcohol alkyl ethers such as ethylene glycol mono-n-butyl ether, and ethylene glycol monophenyl ether) Examples of organic solvents include polyhydric alcohol aryl ethers (such as methyl ethyl ketone, methyl isobutyl ketone, and cyclopentanone), esters (such as butyl acetate, propyl propionate, and methyl ether acetate), amides (such as N,N-dimethylformaldehyde and N,N-dimethylacetamide), amines (such as monoethanolamine and diethanolamine), aromatic hydrocarbons (such as toluene and xylene), sulfur-containing compounds (such as dimethyl sulfoxide), and nitrogen-containing heterocyclic compounds (such as N-methyl-2-pyrrolidone and γ-butyrolactone). These organic solvents may be used individually or in combination of two or more. The concentration of the thermoplastic resin in the organic solvent may be, for example, about 0.1% to 20% by mass.

[0056] The plating catalyst raw material contains a precious metal. The precious metal is not particularly limited and includes, for example, palladium, silver, gold, platinum, nickel, and alloys thereof. These precious metals may be used individually or in combination of two or more.

[0057] The plating catalyst raw material may be prepared by directly adding a precious metal, or by adding a precious metal compound and a reducing agent to reduce the precious metal compound and obtain the precious metal, thereby precipitating the precious metal in the plating catalyst raw material by a reduction reaction. The precious metal compound is not particularly limited and includes, for example, palladium compounds (e.g., palladium chloride, palladium fluoride, palladium bromide, palladium iodide, palladium nitrate, palladium sulfate, palladium oxide, and palladium sulfide), silver compounds (e.g., silver nitrate, silver fluoride, silver oxide, and silver acetate), gold compounds (e.g., gold cyanide, gold trichloride, gold tribromide, potassium gold chloride, potassium gold cyanide, sodium gold chloride, and sodium gold cyanide), platinum compounds (e.g., platinum chloride and platinum sulfate), and nickel compounds (e.g., nickel chloride and nickel sulfate). These precious metal compounds may be used individually or in combination of two or more.

[0058] The reducing agent is not particularly limited and includes, for example, metal borohydride salts (e.g., sodium borohydride and potassium borohydride), aluminum hydride salts (e.g., lithium aluminum hydride, potassium aluminum hydride, cesium aluminum hydride, beryllium aluminum hydride, magnesium aluminum hydride, and calcium aluminum hydride), hydrazine compounds, carboxylic acids (e.g., citric acid, formic acid, acetic acid, fumaric acid, malic acid, succinic acid, ascorbic acid and their salts), primary or secondary alcohols (e.g., methanol, ethanol, isopropanol, and polyols), tertiary amines (e.g., trimethylamine, triethylamine, diisopropylethylamine, diethylmethylamine, tetramethylethylenediamine [TMEDA], and ethylenediamine). Examples include mintetraacetic acid [EDTA], hydroxylamines, ketones (e.g., acetone and methyl ethyl ketone), ethers (e.g., diethyl ether), aldehydes (e.g., formaldehyde and acetaldehyde), esters (e.g., methyl formate, methyl acetate, and ethyl acetate), and phosphines (e.g., tri-n-propylphosphine, tri-n-butylphosphine, tricyclohexylphosphine, tripenzylphosphine, triphenylphosphine, triethoxyphosphine, 1,2-bis(diphenylphosphino)ethane [DPPE], 1,3-bis(diphenylphosphino)propane [DPPP], 1,1'-bis(diphenylphosphino)ferrocene [DPPF], and 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl [BINAP]). These reducing agents can be used individually or in combination of two or more.

[0059] The amount of reducing agent used is not particularly limited; for example, it may be about 10 to 1000 parts by mass per 100 parts by mass of the noble metal compound.

[0060] Examples of dispersants include those exemplified as dispersants in the section on laminates. In the plating layer formation process, for example, the dispersant is used in a form dissolved or dispersed in an organic solvent. Examples of organic solvents include those exemplified as solvents capable of dissolving or dispersing thermoplastic resins. The concentration of the dispersant in the organic solvent may be, for example, about 0.1% to 10% by mass.

[0061] In the plating layer formation process, a mixed raw material, obtained by mixing a thermoplastic resin, a plating catalyst raw material, and a dispersant as needed, may be applied to at least one surface of the substrate and dried to form the plating layer. Alternatively, in the plating layer formation process, a resin layer may be formed by applying a thermoplastic resin to at least one surface of the substrate and drying it, and a catalyst layer may be formed by applying the plating catalyst raw material and a dispersant as needed to the surface of the resin layer and drying it. In this case, the plating layer consists of a resin layer and a catalyst layer.

[0062] In the plating layer formation process, the method for applying the thermoplastic resin, the plating catalyst raw material, and, if necessary, the dispersant is not particularly limited and includes, for example, the roll coating method, kiss roll coating method, gravure coating method, reverse coating method, roll brush method, spray coating method, dip roll coating method, bar coating method, knife coating method, air knife coating method, curtain coating method, lip coating method, and die coating method.

[0063] The drying conditions in the plating layer formation process can be appropriately set by adjusting the drying temperature and time depending on the organic solvent used. For example, the drying temperature range is approximately 60°C to 300°C, and the drying time is approximately 5 minutes to 60 minutes. The drying temperature may be changed in stages or maintained at a constant temperature.

[0064] (Plating layer formation process) The plating layer formation process involves forming a plating layer by performing a plating treatment on the surface opposite to the substrate of the adhesive layer. Plating treatments include electroless plating, electroplating, and combinations thereof. Among these plating treatments, electroless plating is preferred because it can be applied to the semi-additive method, one of the pattern formation methods, and can accommodate narrow-pitch patterns on both sides.

[0065] For the electroless plating and electroplating processes, known processing conditions are used. More specifically, the processing conditions described in the examples are used.

[0066] Unless otherwise specified, the physical properties described herein can be measured in accordance with the methods described in the following examples. [Examples]

[0067] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0068] The following describes specific examples of the synthesis of thermoplastic resins, which are the raw materials for the resin layer of the present invention. However, the present invention is not limited to these synthesis examples.

[0069] The dianhydrides, diamines, and solvents used in the synthesis of the thermoplastic resin are as follows:

[0070] p-PDA: p-phenylenediamine (manufactured by Kanto Chemical Co., Ltd.) BAPP: 2,2-bis(4-aminophenoxyphenyl)isopropane (manufactured by Wakayama Seika Kogyo Co., Ltd.) TPE-R: 1,3-bis(4-aminophenoxy)benzene (manufactured by Wakayama Seika Kogyo Co., Ltd.) 4,4'-DPE: 4,4'-diaminodiphenyl ether (manufactured by Wakayama Seika Kogyo Co., Ltd.) BPDA: 3,4,3',4'-biphenyltetracarboxylic acid dianhydride (manufactured by Ube Industries, Ltd.) DMAc: N,N-dimethylacetamide (manufactured by Kanto Chemical Co., Ltd.) NMP: N-methyl-2-pyrrolidone (manufactured by Kanto Chemical Co., Ltd.)

[0071] [Synthesis Example 1] 85 g of DMAc, 1.034 g (0.003 mol) of BAPP, and 6.628 g (0.023 mol) of TPE-R were added to a reaction vessel, and the mixture was stirred at room temperature to dissolve the BAPP and TPE-R in the DMAc. 7.338 g (0.025 mol) of BPDA was gradually added to the resulting solution. The mixture was then stirred at room temperature for 3 hours to obtain a resin composition (polyamic acid solution). The obtained polyamic acid solution was diluted with DMAc to a solid content concentration of 2% by mass to obtain polyamic acid solution A.

[0072] [Synthesis Example 2] 85 g of DMAc, 5.645 g (0.014 mol) of BAPP, and 2.680 g (0.009 mol) of TPE-R were added to a reaction vessel, and the mixture was stirred at room temperature to dissolve the BAPP and TPE-R in the DMAc. 6.675 g (0.023 mol) of BPDA was gradually added to the resulting solution. The mixture was then stirred at room temperature for 3 hours to obtain a resin composition (polyamic acid solution). The obtained polyamic acid solution was diluted with DMAc to a solid content concentration of 2% by mass to obtain polyamic acid solution B.

[0073] [Synthesis Example 3] 85 g of DMAc and 4.061 g (0.038 mol) of p-PDA were added to a reaction vessel, and the mixture was stirred at 40°C to dissolve the p-PDA in the DMAc. 10.939 g (0.037 mol) of BPDA was gradually added to the resulting solution. The mixture was then stirred at room temperature for 3 hours to obtain a resin composition (polyamic acid solution). The obtained polyamic acid solution was diluted with DMAc to a solid content concentration of 2% by mass to obtain polyamic acid solution C.

[0074] [Example 1] As a substrate, a thermosetting polyimide resin film with a thickness of 38 μm (Toray DuPont Co., Ltd.'s "Kapton 150EN-C, linear thermal expansion coefficient 13 ppm, glass transition temperature 320°C, Ra 0.03 μm") was coated onto one side using a bar coater with a 2% by mass polyamic acid solution A, which is a precursor resin solution of the thermoplastic polyimide resin synthesized in Synthesis Example 1. The film was then dried at 60°C to 250°C for about 10 minutes to form a resin layer with a thickness of 150 nm (resin layer formation step). Next, a chemical agent A (Nissan Chemical Corporation's CP series) containing Pd as a plating catalyst and a dispersant having an ammonium group was coated onto the surface of the resin layer using a bar coater. The film was dried at 120°C for about 10 minutes, and then further dried at 250°C for about 15 minutes to form a catalyst layer with a thickness of 50 nm (catalyst layer formation step). The formed material was immersed for approximately 5 minutes in OPC Copper HFS (initial Cu concentration 2.5 g / l, bath volume 500 ml, 40°C, 40 minutes), a product of Okuno Pharmaceutical Co., Ltd., to form a metal plating layer with a thickness of 0.3 μm on the surface of the catalyst layer (chemical plating process). Furthermore, the thickness of the metal plating layer was increased from 0.3 μm to 12 μm by electroplating (electroplating process). This resulted in obtaining a laminate. Observation of the cross-sectional view of the obtained laminate using a scanning electron microscope revealed that a boundary layer was formed between the resin layer and the catalyst layer. A cross-sectional view of the obtained laminate is shown in Figure 1. As shown in Figure 1, this laminate consists of a resin layer, a boundary layer, and a catalyst layer laminated on a substrate in this order.

[0075] [Example 2] A laminate was obtained in the same manner as in Example 1, except that in the resin layer formation process, 2% by mass polyamic acid solution B, which is a precursor resin solution for thermoplastic polyamide resin synthesized in Synthesis Example 2, was used instead of 2% by mass polyamic acid solution A, which is a precursor resin solution for thermoplastic polyimide resin synthesized in Synthesis Example 1.

[0076] [Comparative Example 1] A laminate was obtained in the same manner as in Example 1, except that in the resin layer formation process, 2% by mass polyamic acid solution C, which is a precursor resin solution for thermosetting polyimide resin synthesized in Synthesis Example 3, was used instead of 2% by mass polyamic acid solution A, which is a precursor resin solution for thermoplastic polyimide resin synthesized in Synthesis Example 1.

[0077] [Comparative Example 2] A laminate was obtained in the same manner as in Example 1, except that the resin layer formation step was omitted and the above-mentioned agent A was applied to one side of the substrate during the catalyst layer formation step.

[0078] [Example 3] A 2% by mass polyamic acid solution A, a precursor resin solution of the thermoplastic polyimide resin synthesized in Synthesis Example 1, and drug A from Example 1 were mixed in a mass ratio of 10:1 (resin concentration 0.5% by mass, Pd concentration 0.136% by mass). This solution was applied to one side of a substrate using a bar coater, dried at 120°C for about 10 minutes, and then dried again at 250°C for about 15 minutes to form a plating layer with a thickness of 100 nm. The thus formed structure was immersed in OPC Copper HFS (initial Cu concentration 2.5 g / l, bath volume 500 ml, 40°C, 40 minutes) from Okuno Pharmaceutical Co., Ltd. for about 5 minutes to form a metal plating layer with a thickness of 0.3 μm on the surface of the catalyst layer (chemical plating process). Furthermore, the thickness of the metal plating layer was increased from 0.3 μm to 12 μm by electroplating (electroplating process). This obtained a laminate.

[0079] [Example 4] As a substrate, a 25 μm bond ply film, "Pixio FRS-142, coefficient of linear expansion 20 ppm," manufactured by Kaneka Corporation, having thermoplastic polyimide resin layers on both sides of a thermosetting resin layer, was immersed in a 10 wt% KOH aqueous solution at 40°C for about 60 minutes to swell the polyimide resin layer. Then, a chemical agent A containing Pd as a plating catalyst and a dispersant having an ammonium group was applied to one side of the substrate surface using a bar coater, dried at 120°C for about 10 minutes, and further dried at 250°C for about 15 minutes to form a catalyst layer with a thickness of 50 nm. A laminate was obtained from the thus formed body in the same manner as in Example 1.

[0080] [Example 5] As a substrate, a 25 μm bond ply film, "Pixio FRS-142, coefficient of linear expansion 20 ppm," manufactured by Kaneka Corporation, having thermoplastic polyimide resin layers on both sides of a thermosetting resin layer, was used. Agent A, containing Pd as a plating catalyst and a dispersant having ammonium groups, was applied to one side of the substrate surface using a bar coater, dried at 120°C for about 10 minutes, and then dried again at 300°C for about 30 minutes under a nitrogen atmosphere to form a catalyst layer with a thickness of 50 nm. A laminate was obtained from the thus formed body in the same manner as in Example 1.

[0081] The physical properties of the laminates of each example and comparative example were measured. The measurement results are shown in Table 1. From these measurement results, it was found that the less metal present in the resin layer on the substrate side, including the plating and plating catalyst raw materials, the less the decrease in peel strength after heat treatment or moist heat treatment. One possible reason for this, although speculative, is that the effect of heat applied to the resin is smaller due to the low presence of the metal in the resin layer. The measurement methods for each physical property were as follows.

[0082] The evaluation and measurement methods are as follows:

[0083] [Thickness of each layer] The thickness of each layer was measured by cutting the sample to a thickness of 50-150 nm using an ultramicrotome EM UC6 (LEICA), observing the cross-sectional transmission image using a scanning electron microscope S-4800 (Hitachi), and calculating the thickness from there. [Palladium abundance] The amount of palladium present was measured using an X-ray photoelectron spectroscopy analyzer. More specifically, the amount of catalyst present (palladium present (Pd present)) on the surface side of the plating layer was measured from the surface side using an X-ray photoelectron spectroscopy analyzer and determined from the detected atomic% concentration of Pd. Specifically, the amount of catalyst present (palladium present (Pd present)) was defined as the value obtained by dividing the atomic% concentration of palladium (Pd) by the atomic% concentration of carbon (C). The amount of catalyst present on the substrate side of the plating layer was determined by treating the substrate side with argon ions, and after treatment up to a predetermined point, the amount of plating catalyst present (palladium present (Pd present)) on the substrate side of the plating layer was determined using the same method as above with an X-ray photoelectron spectroscopy analyzer. (Evaluation Criteria) ○: It was confirmed that the amount of Pd was greater on the surface side than on the substrate side (Ca > Cb). ×: It was not possible to confirm that the amount of Pd was greater on the surface side than on the substrate side (Ca > Cb).

[0084] [Normal peel strength] Peel strength was measured in accordance with JIS C6471. More specifically, a 3 mm wide etching resist was patterned on the surface of the copper plating layer of each laminate, and then the remaining copper plating layer was removed by etching to obtain a sample. The obtained sample was fixed to a reinforcing plate with double-sided tape, and the peel strength was measured by peeling the copper plating layer from the reinforcing plate at a 90° angle. The peeling speed was set to 50 mm / min. The evaluation criteria in the table are as follows. (Evaluation Criteria) ○: The peel strength was 5N or higher. △: The peel strength was between 3N and 5N. ×: The peel strength was less than 3N.

[0085] [Peel strength after heat treatment] Samples were obtained by patterning an etching resist in a 3 mm width on the surface of the copper plating layer of each laminate, and then removing the remaining copper plating layer by etching. The samples were stored in a dryer adjusted to a temperature of 150°C for 240 hours. The samples removed from the dryer were fixed to a reinforcing plate with double-sided tape, and the copper plating layer was peeled off from the reinforcing plate at a 90° angle, and the peel strength was measured. The peeling speed was set to 50 mm / min. The evaluation criteria in the table are as follows. (Evaluation Criteria) ○: The peel strength was 5N or higher. △: The peel strength was between 3N and 5N. ×: The peel strength was less than 3N.

[0086] [Peel strength after moist heat treatment] Samples were obtained by patterning an etching resist in a 3 mm width on the surface of the copper plating layer of each laminate, and then removing the remaining copper plating layer by etching. The samples were stored for 240 hours in a humid heat oven adjusted to a temperature of 85°C and a humidity of 85%. The samples removed from the dryer were fixed to a reinforcing plate with double-sided tape, and the copper plating layer was peeled off from the reinforcing plate at a 90° angle, and the peel strength was measured. The peeling speed was set to 50 mm / min. The evaluation criteria in the table are as follows. (Evaluation Criteria) ○: The peel strength was 5N or higher. △: The peel strength was between 3N and 5N. ×: The peel strength was less than 3N.

[0087] [Solder heat resistance test] Each laminate was cut to 30mm x 30mm. The copper-plated side of each laminate was placed in the solder bath, and a 60-second float treatment was performed. The appearance after treatment was visually inspected to check for shrinkage, blistering, and peeling. Tests were performed at 10°C intervals from 240°C to 340°C, and the maximum temperature at which no shrinkage, blistering, or peeling occurred was determined. In Table 1, if any of the following occurred at 240°C, it is indicated as "Below 240°C," and if none of the following occurred at 340°C, it is indicated as "340°C<."

[0088] [Table 1]

[0089] This application is based on Japanese Patent Application No. 2018-166271, filed with the Japan Patent Office on September 5, 2018, the contents of which are incorporated herein by reference. [Industrial applicability]

[0090] The laminate of the present invention has industrial applicability as a material used in flexible printed circuit boards.

Claims

1. Substrate and A plating layer containing a thermoplastic resin and a plating catalyst is disposed on at least one of both sides of the substrate, A laminate containing, The aforementioned substrate does not have a polyimide resin precursor layer. The aforementioned plating layer has a multilayer structure of two or more layers. The aforementioned plating layer further satisfies the following conditions (1) and (2): (1) The plating forming layer contains a dispersant (excluding ammonia) that disperses the plating catalyst. (2) The amount of the plating catalyst present on the surface side of the plating layer is greater than the amount of the plating catalyst present on the substrate side of the plating layer. The thermoplastic resin is a thermoplastic polyimide resin. The aforementioned plating catalyst contains a noble metal, The dispersant is a compound that interacts with and binds to the metal atoms contained in the plating catalyst. The aforementioned compound is a compound in which the terminal group of the compound is an ammonium group. The aforementioned bond is a coordinate bond, an ionic bond, or a covalent bond. Laminated structure.

2. The laminate according to claim 1, wherein the plating forming layer comprises a resin layer containing the thermoplastic resin and a catalyst layer disposed on the resin layer and containing the plating catalyst.

3. The laminate according to claim 2, wherein the catalyst layer contains the dispersant.

4. The laminate according to claim 2 or 3, wherein the plating forming layer is disposed between the resin layer and the catalyst layer, and further comprises a boundary layer in which the plating catalyst and the dispersant have permeated the thermoplastic resin.

5. The laminate according to any one of claims 1 to 4, wherein the substrate is a thermosetting polyimide resin.

6. The laminate according to any one of claims 1 to 5, wherein the plating catalyst contains palladium and / or silver.

7. The laminate according to any one of claims 1 to 6, further comprising a metal plating layer disposed on the plating forming layer.

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