Processed copper foil and method for manufacturing the same

Abstract

The objective is to provide a treated copper foil that can adhere firmly to a substrate at a smooth interface with minimal irregularities, and a method for manufacturing the same. Furthermore, the objective is to provide a laminate in which the treated copper foil and the substrate are firmly adhered at a smooth interface with minimal irregularities, and a method for manufacturing the same. [Solution] By using a treated copper foil in which a conductive layer (B) containing silver (b1) is laminated onto a copper foil (A) with a smooth surface, it is possible to firmly adhere the copper foil (A) and the substrate (D) at a smooth interface with minimal irregularities, thus completing the present invention.

Description

[Technical Field]

[0001] The present invention relates to treated copper foil and a method for manufacturing the same. More specifically, it relates to treated copper foil that can adhere firmly to a substrate at a smooth interface with minimal irregularities, and a method for manufacturing the same. Furthermore, it relates to a laminate in which a substrate and treated copper foil are firmly adhered at a smooth interface with minimal irregularities, and a method for manufacturing the same. [Background technology]

[0002] The miniaturization and increased speed of electronic devices have led to demands for higher density and performance in semiconductor package substrates and printed circuit boards. To meet these demands, semiconductor package substrates and printed circuit boards with a smooth metal layer are required. Flexible copper-clad laminates (hereinafter abbreviated as "FCCL") and rigid copper-clad laminates (hereinafter abbreviated as "RCCL") are known as components of printed circuit boards.

[0003] FCCL is mainly manufactured by bonding a heat-resistant polymer film and copper foil with an epoxy resin adhesive, by coating the surface of the copper foil with a varnish such as polyimide and drying it to form a film (casting method), or by heat-pressing a polyimide film having a thermoplastic resin layer with copper foil (lamination method).

[0004] Furthermore, RCCL is manufactured by methods such as bonding fully cured resin or ceramic to copper foil with an epoxy resin adhesive, heating epoxy resin-impregnated glass cloth to create a semi-cured substrate (prepreg) and bonding it to copper foil, and coating a varnish mixed with resin and inorganic filler onto a release film, drying it, and then heat-pressing the resulting resin film onto the surface of copper foil or copper wiring (build-up film). Generally, both FCCL and RCCL adhere to the copper foil and substrate by creating irregularities at the interface between the copper foil and the substrate, which creates an anchoring effect (see, for example, Patent Documents 1, 2, and 3).

[0005] In 5G, which is currently becoming widespread, and in Beyond 5G, which is expected to expand in the future, it is necessary to reduce the transmission loss of high-frequency signals. Transmission loss occurs due to resistance (dielectric loss) caused by the dielectric properties of the substrate and resistance (conductor loss) caused by the surface roughness of the conductor (copper wiring).

[0006] Dielectric loss is a phenomenon in which, when a high-frequency alternating current is passed through a substrate with high dielectric constant or dielectric loss tangent, some of the energy is lost as heat within the dielectric material. To reduce this dielectric loss, it is necessary to reduce the number of polar functional groups contained in the substrate and design the molecule in a way that minimizes the movement of polymer molecular chains. However, polymers with such molecular designs have the drawback of reduced adhesion between the substrate and the copper foil.

[0007] Furthermore, conductor loss is a phenomenon in which, when a high-frequency current flows through a conductor, the electrical signal is scattered by the irregularities (roughened areas) on the surface of the conductor (copper wiring) and lost as heat. To reduce this conductor loss, it is necessary to reduce the surface roughness of the conductor (copper foil). However, with conventional methods that use the anchoring effect to adhere the copper foil to the substrate, there is a problem in that the adhesion between the substrate and the copper foil decreases as the surface roughness of the copper foil decreases.

[0008] Therefore, in semiconductor package substrates and printed circuit boards where transmission loss reduction is required in the future, as mentioned above, it is necessary to form conductors (copper wiring) at the smoothest possible interface on substrates with low dielectric constant and low dielectric loss tangent, which are disadvantageous in terms of adhesion with copper foil, and new copper foils are needed. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2003-69218 [Patent Document 2] Japanese Patent Publication No. 2003-249751 [Patent Document 3] Patent No. 5524833 [Overview of the project]

Problems to be Solved by the Invention

[0010] The problems to be solved by the present invention are to provide a treated copper foil capable of firmly adhering to a substrate with a small and smooth interface having irregularities, and a method for producing the same. Further, it is to provide a laminate in which a substrate and a treated copper foil are firmly adhered with a small and smooth interface having irregularities, and a method for producing the same.

[0011] As a result of intensive research to solve the above problems, the present inventors have found that by using a treated copper foil in which a conductive layer (B) containing silver (b1) is laminated on a copper foil (A) having a surface with small irregularities, the copper foil (A) and the substrate (D) can be firmly adhered with a small and smooth interface, and thus completed the present invention.

[0012] That is, specifically, the present invention provides: 1. A treated copper foil in which a conductive layer (B) containing silver (b1) is laminated on at least one surface of a copper foil (A). 2. The treated copper foil according to 1, wherein the conductive layer (B) further contains a dispersant (b2). 3. The treated copper foil according to 2, wherein the dispersant (b2) has a basic nitrogen atom-containing group. 4. The treated copper foil according to any one of 1 to 3, wherein the surface resistivity of the conductive layer (B) containing silver (b1) is 0.01 Ω / sq or more and 3.00 Ω / sq or less. 5. The treated copper foil according to any one of 1 to 3, wherein the silver (b1) forming the conductive layer (B) is particles having a particle size of 30 nm or more and 1000 nm or less and a volume fraction of 50% or more obtained by the small-angle X-ray scattering method. 6. On the surface forming the conductive layer (B), the conductivity at 15.6 GHz measured using the equilibrium disk resonator method is 2.0×10 7 S / m or more and 6.0×10 7 S / m or less, and the conductivity at 54.5 GHz is 1.3×10 7 S / m or more and 5.5×10 7A treated copper foil according to any one of 1 to 3, characterized in that it is S / m or less. 7. The treated copper foil according to any one of claims 1 to 3, characterized in that the copper foil (A) on which the conductive layer (B) is laminated has a surface roughness Sz of the surface on the conductive layer (B) side of 0.1 μm or more and 2.0 μm or less. 8. The conductive layer (B) is 300 mg / m² 2 More than 10,000mg / m 2 A treated copper foil according to any one of 1 to 3, characterized in that it is formed with the following weights. 9. The treated copper foil according to any one of claims 1 to 3, characterized in that a resin layer (C) is further laminated on the conductive layer (B). 10. The treated copper foil according to claim 9, characterized in that the resin layer (C) is a resin layer (C) containing a compound (c1) having a functional group [X]. 11. The treated copper foil according to claim 10, characterized in that the functional group [X] is one or more functional groups selected from epoxy groups, carboxylic acid groups, carboxylic anhydride groups, keto groups, alkylolamide groups, isocyanate groups, vinyl groups, alkyl halide groups, acryloyl groups, cyanamide groups, carbamide groups, and acyl halide groups. 12. The treated copper foil according to claim 9, characterized in that the thickness of the resin layer (C) is 0.01 μm or more and 10 μm or less. 13. A laminate in which the conductive layer (B) side of the treated copper foil described in 1 is in contact with at least one surface of the substrate (D). 14. A laminate in which the resin layer (C) side of the treated copper foil described in 9 is in contact with at least one surface of the substrate (D). 15. The laminate according to claim 13, characterized in that the base material (D) is an insulating resin base material. 16. The laminate according to claim 14, characterized in that the base material (D) is an insulating resin base material. 17. The laminate according to claim 13, characterized in that the peel strength of the treated copper foil in the laminate according to the method specified in JISC6481 is 0.4 kN / m or more. 18. The laminate according to claim 14, characterized in that the peel strength of the treated copper foil in the laminate according to the method specified in JISC6481 is 0.4 kN / m or more. 19. The laminate according to claim 13, characterized in that when the copper foil (A) is removed, the surface resistivity of the conductive layer (B) on the surface where the copper foil (A) was removed is 0.01 Ω / □ or more and 3.00 Ω / □ or less. 20. The laminate according to claim 14, characterized in that when the copper foil (A) is removed, the surface resistivity of the conductive layer (B) on the surface where the copper foil (A) was removed is 0.01 Ω / □ or more and 3.00 Ω / □ or less. 21. Step 1 of manufacturing a treated copper foil by laminating a conductive layer (B) containing silver (b1) onto at least one surface of a copper foil (A), Step 2 involves overlapping the conductive layer (B) side of the treated copper foil with the substrate (D) and heat-pressing the entire assembly. A method for manufacturing a laminate according to claim 13, characterized by having the following: 22. Step 1 for manufacturing treated copper foil, in which a conductive layer (B) containing silver (b1) and a resin layer (C) are sequentially laminated on at least one surface of copper foil (A), Step 2 involves overlapping the resin layer (C) side of the treated copper foil with the substrate (D) and heat-pressing the entire assembly. A method for manufacturing a laminate according to claim 14, characterized by having the following: [Effects of the Invention]

[0013] The treated copper foil of the present invention is a copper foil in which a conductive layer (B) containing silver (b1) is laminated onto a copper foil (A) with a surface that has small irregularities. By laminating this treated copper foil to both sides or one side of a substrate (D), the copper foil (A) and the substrate (D) can be firmly bonded together. Compared to conventional methods that use copper foil with large irregularities, this copper foil has a smooth interface with small irregularities, allowing for a firm bond between the copper foil (A) and the substrate (D).

[0014] Furthermore, the treated copper foil of the present invention can be suitably used in the manufacture of electronic components such as flexible printed circuit boards, rigid printed circuit boards, semiconductor package substrates, ceramic substrates, glass substrates, silicon wafer substrates, metal substrates, conductive films for touch panels, metal meshes for touch panels, organic solar cells, organic EL elements, organic transistors, RFID such as contactless IC cards, electromagnetic shielding, LED lighting substrates, and digital signage. It is particularly ideal for semiconductor package substrates, flexible printed circuit boards, and rigid printed circuit boards. [Modes for carrying out the invention]

[0015] The present invention relates to a treated copper foil in which a conductive layer (B) containing silver (b1) is laminated on at least one surface of a copper foil (A), and a method for manufacturing the same. Furthermore, the present invention relates to a laminate in which the treated copper foil is laminated on at least one surface of a substrate (D), and a method for manufacturing the same.

[0016] The copper foil (A) used to manufacture the treated copper foil of the present invention is not particularly limited as long as it is a known copper foil used in printed circuit boards, but preferably electrolytic copper foil, rolled copper foil, or copper alloys thereof are used, and the thickness of the copper foil is not particularly limited but preferably 1 μm to 100 μm. If the copper foil is thin, it is difficult to handle, so an ultra-thin copper foil with a carrier can be used (for example, MicroThin manufactured by Mitsui Mining & Smelting Co., Ltd.). Normally, a roughening treatment to which the surface roughness Sz of the copper foil becomes 2.5 to 5.0 μm is essential to impart adhesion to the substrate, but the smaller the surface roughness Sz of the copper foil (A), the better, and it is preferable to use copper foil that is controlled to 2.0 μm or less, and more preferably 1.0 μm or less. The surface treatment of the copper foil can be any known technology, and there are no particular limitations on the surface treatment means, but for example, there are methods of attaching and forming fine metal particles on the surface of electrolytic copper foil, and methods of forming a roughened surface by etching. Furthermore, surface treatments may be applied as needed to remove fine metal particles or prevent rust, such as surface treatment with nickel, zinc, or their alloys, or silane coupling treatment. However, since nickel, zinc, and their alloys have lower conductivity and resistance than copper, it is preferable to perform only the minimum necessary treatment to achieve functions such as rust prevention. In addition, in rust prevention treatment, chromate rust prevention may result in chromium residue remaining after etching for circuit formation, raising concerns about reduced insulation reliability, so it is better not to use chromium. Also, the presence of chromium on the surface of the copper foil may reduce adhesion with the conductive layer (B) described later. Surface roughness (maximum height Sz) is measured using the evaluation method described in ISO 25178 and represents the distance from the highest point to the lowest point on the surface.

[0017] Next, we will explain the conductive layer (B). In the present invention, it is preferable that the resistivity of the conductive layer (B) is low in order to reduce transmission loss in the high-frequency range. The surface resistivity of the conductive layer (B) containing silver (b1) is preferably 0.01 Ω / □ or more and 3.00 Ω / □ or less, more preferably 0.05 Ω / □ or more and 2.00 Ω / □ or less, and even more preferably 0.05 Ω / □ or more and 1.00 Ω / □ or less.

[0018] The produced conductive layer (B) is a layer containing silver (b1). The average particle diameter with a volume fraction of 50% or more obtained by small-angle X-ray scattering of silver (b1) is preferably 30 nm or more and 1,000 nm or less, more preferably 50 nm or more and 800 nm or less, and even more preferably 50 nm or more and 600 nm or less. The larger the average particle diameter obtained by small-angle X-ray scattering of the conductive layer (B), the smaller the surface resistivity of the conductive layer (B), and the higher the conductivity of the surface of the treated copper foil of the conductive layer (B) described later, which is preferable. The evaluation of the particle diameter by small-angle X-ray scattering can calculate the volume fraction and the average particle diameter by, for example, the USAX method (2θ = 0 to 4 deg) using SmartLab manufactured by Rigaku Corporation.

[0019] In order to reduce the transmission loss in the high-frequency region, the produced conductive layer (B) preferably has a high conductivity on the surface of the treated copper foil. The conductivity measurement of the surface of the treated copper foil can be performed using a network analyzer and a resonator. As the resonator, a Fabry-Perot resonator or a balanced disk resonator manufactured by EM Lab Co., Ltd. can be used. Using the balanced disk resonator method, the conductivity of the surface of the treated copper foil on which the conductive layer (B) is formed is such that the conductivity at 15.6 GHz is 2.0×10 7 S / m or more and 6.0×10 7 S / m or less, and the conductivity at 54.5 GHz is 1.3×10 7 S / m or more and 5.5×10 7 S / m or less is preferable.

[0020] The surface roughness Sz of the surface of the treated copper foil on the conductive layer (B) side where the conductive layer (B) is laminated is preferably 0.1 μm or more and 2.0 μm or less, more preferably 0.1 μm or more and 1.5 μm or less, and even more preferably 0.1 μm or more and 1.0 μm or less. The surface roughness (maximum height Sz) is measured by the evaluation method described in ISO25178 and represents the distance from the highest point to the lowest point on the surface.

[0021] The silver used to fabricate the conductive layer (B) is preferably in particulate or fibrous form. If the silver is in particulate form, its size is preferably nano-sized. Specifically, to create a denser coating and further reduce resistance, the average particle diameter measured by dynamic light scattering is preferably 1 nm to 100 nm, and more preferably 10 nm to 50 nm. The "NanoTrack UPA-150" manufactured by MicroTrack can be used to measure this average particle diameter by dynamic light scattering. If the silver is in fibrous form, to create a denser coating and further reduce resistance, the fiber diameter is preferably 5 nm to 100 nm, and more preferably 5 nm to 50 nm. The fiber length is preferably 0.1 μm to 100 μm, and more preferably 0.1 μm to 30 μm.

[0022] The conductive layer (B) may further contain a dispersant (b2). Preferably, the dispersant (b2) is contained in an amount of 0.1% to 20% by mass relative to the entire conductive layer (B), and more preferably in an amount of 0.1% to 10% by mass.

[0023] By using a compound having a basic nitrogen atom-containing group that interacts with the metal as the dispersant (b2) contained in the conductive layer (B), the compound interacts with the copper foil (A), thereby improving the adhesion between the copper foil (A) and the conductive layer (B). Furthermore, by reacting the functional group of the compound (c1) contained in the resin layer (C), described later, with the compound having a basic nitrogen atom-containing group in the dispersant (b2), a chemical bond is formed, improving the adhesion between the conductive layer (B) and the resin layer (C). In addition, by reacting the compound having a basic nitrogen atom-containing group in the dispersant (b2) with the functional group present in the substrate (D), described later, a chemical bond is formed, improving the adhesion between the conductive layer (B) and the substrate (D). The basic nitrogen atom-containing group may partially react with the functional group to form a chemical bond, or it may react completely to form a chemical bond.

[0024] Examples of the basic nitrogen atom-containing group include imino groups, primary amino groups, and secondary amino groups.

[0025] The dispersant (b2) having a basic nitrogen-containing group is preferably a polymeric dispersant, and as this polymeric dispersant, it is preferable to use a polyalkylene imine such as polyethyleneimine or polypropyleneimine, or a compound obtained by adding a polyoxyalkylene to the polyalkylene imine.

[0026] The dispersant (b2) contained in the conductive layer (B) may be a compound having a phosphate ester group that interacts with metals, and by interacting with the copper foil (A), the adhesion between the copper foil (A) and the conductive layer (B) is improved. Furthermore, by reacting the functional group of the compound (c1) contained in the resin layer (C), which will be described later, with the compound having a phosphate ester group in the dispersant (b2), a chemical bond is formed, improving the adhesion between the conductive layer (B) and the resin layer (C). In addition, the phosphate ester group of the dispersant (b2) reacts with the functional group present in the substrate (D), which will be described later, to form a chemical bond, improving the adhesion between the conductive layer (B) and the substrate (D). The phosphate ester group may partially react with the functional group to form a chemical bond, or it may react completely to form a chemical bond.

[0027] When using a dispersant (b2) that has a phosphate ester group in its molecule, it is preferable to use an acrylic resin that is easy to introduce a phosphate ester group into. When introducing a phosphate ester group into an acrylic resin, a monomer having a phosphate ester group is used as the raw material for the acrylic resin. Examples of monomers having a phosphate ester group include 2-((meth)acryloyloxy)ethyl phosphate, 2-((meth)acryloyloxy)propyl phosphate, diphenyl(2-acryloyloxyethyl) phosphate, diphenyl(2-methacryloyloxyethyl) phosphate, and phenyl(2-acryloyloxyethyl) phosphate.

[0028] Furthermore, when a compound having a phosphate ester group is used as the dispersant (b2), a functional group [Y] other than the phosphate ester group may be used in combination. Examples of functional groups [Y] include carboxyl groups, isocyanate groups, blocked isocyanate groups, epoxy groups, hydroxyl groups, oxazoline groups, N-methylol groups, N-alkoxymethyl groups, amino groups, alkoxysilyl groups, and the like. In addition, the dispersant (b1) may have two or more of these functional groups.

[0029] The content of the functional group [Y] in the dispersant (b2) is preferably 1 mmol / kg to 5,000 mmol / kg, more preferably 10 mmol / g to 3,000 mmol / kg, and even more preferably 10 mmol / kg to 2,000 mmol / kg, in order to further improve the adhesion between the copper foil (A) and the conductive layer (B), or between the conductive layer (B) and the resin layer (C) described later.

[0030] The distribution of silver (b1) and dispersant (b2) in the conductive layer (B) is not limited as long as conductivity is ensured, but one preferred form is one in which the dispersant (b2) is localized at the interface between the copper foil (A) and the conductive layer (B), and at the interface between the conductive layer (B) and air.

[0031] When there is a large amount of dispersant (b2) localized at the interface between the copper foil (A) and the conductive layer (B), it is more likely to contribute to the interaction with the copper foil (A), thus improving the adhesion between the copper foil (A) and the conductive layer (B).

[0032] When a resin layer (C), described later, is formed at the interface between the conductive layer (B) and air, a large amount of dispersant (b2) is localized at the air interface. This makes it easier for the functional groups of the dispersant (b2) to form chemical bonds with the functional groups [X] of the compound (c1) contained in the resin layer (C), thereby improving the adhesion between the conductive layer (B) and the resin layer (C).

[0033] The conductive layer (B) can be formed by preparing and applying a fluid containing silver (b1) and a dispersant (b2).

[0034] The content of silver (b1) in the fluid is preferably 1% by mass or more and 90% by mass or less, more preferably 1% by mass or more and 60% by mass or less, and even more preferably 1% by mass or more and 30% by mass or less. Components that may be incorporated into the fluid include dispersants and solvents for dispersing silver (b1) in the solvent, and, if necessary, surfactants, leveling agents, viscosity modifiers, film-forming aids, defoaming agents, preservatives, etc., as described later.

[0035] To disperse silver (b1) in the solvent, other dispersants may be used in combination with the dispersant (b1). Examples of dispersants that can be used in combination include dodecanethiol, 1-octanthiol, triphenylphosphine, dodecylamine, polyethylene glycol, polyvinylpyrrolidone, polyethyleneimine, polyvinylpyrrolidone; fatty acids such as myristic acid, octanoic acid, and stearic acid; polycyclic hydrocarbon compounds having carboxyl groups such as cholic acid, glycyrrhizic acid, and abietic acid; urethane resins; acrylic resins; and compounds containing phosphate groups in the urethane resins or acrylic resins.

[0036] The amount of dispersant used in combination with dispersant (b1) is preferably 0.01 parts by mass or more and 50 parts by mass or less, and more preferably 0.01 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of silver (b1).

[0037] As the solvent used in the fluid, aqueous media or organic solvents can be used. Examples of aqueous media include distilled water, deionized water, pure water, and ultrapure water. Examples of organic solvents include alcohol compounds, ether compounds, ester compounds, and ketone compounds.

[0038] Examples of the aforementioned alcohol compounds include methanol, ethanol, n-propanol, isopropyl alcohol, n-butanol, isobutyl alcohol, sec-butanol, tert-butanol, heptanol, hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, stearyl alcohol, allyl alcohol, cyclohexanol, terpineol, terpineol, dihydroterpineol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol monobutyl ether.

[0039] In addition to the solvent, the fluid may optionally contain ethylene glycol, diethylene glycol, 1,3-butanediol, isoprene glycol, glycerin, etc.

[0040] The aforementioned fluid can be a general surfactant, such as di-2-ethylhexyl sulfosuccinate, dodecylbenzenesulfonate, alkyldiphenyl ether disulfonate, alkylnaphthalene sulfonate, hexametaphosphate, etc.

[0041] The fluid can be a general leveling agent, such as a silicone compound, an acetylenediol compound, or a fluorine compound.

[0042] The fluid can be thickened with a general-purpose thickener, such as acrylic polymers or synthetic rubber latex that can be thickened by adjusting to an alkaline state, urethane resins that can be thickened by molecular association, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, polyvinyl alcohol, water-added castor oil, amide wax, oxidized polyethylene, metal soap, dibenzylidene sorbitol, etc.

[0043] The aforementioned fluid can be a general film-forming aid, such as anionic surfactants (e.g., dioctyl sulfosuccinate sodium salt), hydrophobic nonionic surfactants (e.g., sorbitan monooleate), polyether-modified siloxanes, and silicone oils.

[0044] The aforementioned fluid can be a general-purpose defoaming agent, such as a silicone-based defoaming agent, a nonionic surfactant, a polyether, a higher alcohol, or a polymer-based surfactant.

[0045] The aforementioned fluid can be treated with general preservatives, such as isothiazolinoline preservatives, triazine preservatives, imidazole preservatives, pyridine preservatives, azole preservatives, and pyrithione preservatives.

[0046] The viscosity of the fluid (measured using a Type B viscometer at 25°C) is preferably 0.1 mPa·s to 500,000 mPa·s, and more preferably 0.2 mPa·s to 10,000 mPa·s. Furthermore, when the fluid is coated (printed) by methods such as inkjet printing or relief printing described later, the viscosity is preferably in the range of 5 mPa·s to 20 mPa·s.

[0047] One method for manufacturing copper foil according to the present invention is to first coat a copper foil (A) with a fluid containing silver (b1) and a dispersant (b2), and then remove organic solvents and the like contained in the fluid by drying to form a conductive layer (B).

[0048] Methods for coating or printing the fluid onto the copper foil (A) include, for example, inkjet printing, reverse printing, screen printing, offset printing, gravure printing, flexographic printing, pad printing, spin coating, spray coating, bar coating, die coating, slit coating, roll coating, dip coating, rotary coating, capillary coating, microgravure coating, doctor roll method, etc.

[0049] When forming the conductive layer (B), for example, by coating or printing, the conductive layer (B) may be formed in a single coating or printing step, or it may be formed in two or more steps. In this case, as long as the conductivity of the conductive layer (B) is ensured, the conductive layer (B) may consist of one layer or two or more layers. When two or more conductive layers (B) are formed, as long as the conductivity of the conductive layer (B) is ensured, for example, in cross-sectional observation, the first layer may be recognized as a different layer from the second and subsequent layers, or they may be recognized as a single layer.

[0050] The drying temperature after coating or printing the fluid containing silver (b1) and dispersant (b2) is preferably 50°C to 400°C, more preferably 80°C to 300°C, and even more preferably 120°C to 250°C.

[0051] The drying may be carried out with or without blowing air. The drying may also be carried out in the atmosphere, in a displacement atmosphere of an inert gas such as nitrogen or argon, under a flow of air, or under a vacuum.

[0052] The weight per unit area of ​​the conductive layer (B) is 300 mg / m² to ensure adhesion between the copper foil (A) and the conductive layer (B), and between the resin layer (C) and the conductive layer (B), as described later. 2 More than 10,000mg / m 2 The following is preferred: 300 mg / m² 2 More than 8,000mg / m 2 The following is more preferable: 300 mg / m² 2 More than 6,000mg / m2 The following are even more preferable.

[0053] Next, we will explain the resin layer (C). The resin layer (C) is a layer that can be provided for the purpose of improving the adhesion between the conductive layer (B) and the substrate (D) described later.

[0054] The resin layer (C) is formed by applying a composition containing a compound (c1) having a functional group [X] to the surface of the conductive layer (B) and drying it. The resin layer (C) forms chemical bonds when the functional group [X] present in the coating reacts with the basic nitrogen atom-containing group or phosphate ester group of the dispersant (b2) contained in the conductive layer (B). The reaction proceeds and chemical bonds are formed even at room temperature, but heating further accelerates the reaction and forms chemical bonds. This improves adhesion at the interface between the conductive layer (B) and the resin layer (C).

[0055] Examples of functional groups [X] include epoxy groups, carboxylic acid groups, carboxylic anhydride groups, keto groups, alkylolamide groups, isocyanate groups, vinyl groups, alkyl halide groups, acryloyl groups, cyanamide groups, carbamide groups (urea bonded), acyl halide groups, etc., and one or more functional groups selected from these can be used. The keto group refers to a carbonyl group derived from a ketone. The isocyanate group may be encapsulated with a blocking agent to prevent reaction at room temperature.

[0056] In particular, as the functional group [X], it is preferable to use one or more selected from the group consisting of epoxy groups, carboxylic acid groups, carboxylic anhydride groups, keto groups, alkylolamide groups, and isocyanate groups, from the viewpoint of preventing the formation of by-products such as halogens, acids, and amines when reacted with the dispersant (b2).

[0057] The functional group [X] is preferably present in the entire resin layer (C) at a concentration of 50 mmol / kg or more and 10,000 mmol / kg or less, more preferably at a concentration of 100 mmol / kg or more and 8,000 mmol / kg or less, and even more preferably at a concentration of 100 mmol / kg or more and 5,000 mmol / kg or less, in order to further improve adhesion.

[0058] Examples of compositions containing a compound (c1) having a functional group [X] that forms a resin layer (C) include urethane resin, acrylic resin, core-shell type composite resin with urethane resin as the shell and acrylic resin as the core, epoxy resin, phenoxy resin, imide resin, amide resin, melamine resin, phenol resin, novolac resin, urea-formaldehyde resin, blocked isocyanate polyvinyl alcohol obtained by reacting polyisocyanate with a blocking agent such as phenol, and polyvinylpyrrolidone. Note that the core-shell type composite resin with urethane resin as the shell and acrylic resin as the core can be obtained, for example, by polymerizing an acrylic monomer in the presence of urethane resin. Furthermore, these resins can be used individually or in combination of two or more.

[0059] Among the resins that form the resin layer (C), bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, and bisphenol A novolac type epoxy resin are preferred because they can further improve adhesion, and naphthalene type epoxy resin is particularly preferred. Furthermore, the epoxy equivalent of the epoxy resin is preferably 100 g / eq to 300 g / eq, more preferably 120 g / eq to 250 g / eq, and even more preferably 150 g / eq to 200 g / eq, in order to further improve adhesion.

[0060] Among the resins forming the resin layer (C), it is preferable to use one that contains an aminotriazine-modified novolac resin. The phenolic hydroxyl group (functional group [X]) of the aminotriazine novolac resin and the dispersant (b2) contained in the conductive layer (B) form an ionic bond through an acid-base reaction, thereby improving the adhesion at the interface between the conductive layer (B) and the resin layer (C).

[0061] Among the resins forming the resin layer (C), it is preferable to use one that contains a phenoxy resin. It is preferable to use a phenoxy resin with a weight-average molecular weight of 10,000 or more and 100,000 or less. By using a high molecular weight phenoxy resin in the resin layer (C), the elongation of the polymer is improved, and the elastic modulus is further improved, thereby improving the adhesion between the substrate (D) and the conductive layer (B) in a laminate formed by bonding the surface of the resin layer (C) to the substrate (D) described later.

[0062] The aforementioned phenoxy resin may be a commercially available product, for example, 1256, 4250 (both phenoxy resins containing a bisphenol A skeleton), 4275 (bis A / bis F mixed type), YL6794, YL7213, YL7290, YL7482, YL7553, YX8100 (phenoxy resin containing a bisphenol S skeleton), X6954 (phenoxy resin containing a bisphenol acetophenone skeleton), YX7200 ( Examples include phenoxy resins containing a cyclohexane skeleton, YP-70 (bisphenol F type phenoxy resin), ZX356-2 (phenoxy resins containing bisphenol A and bisphenol F skeletons) from Nippon Steel Chemical & Material Co., Ltd., YPB-40PXM40 (phenoxy resins containing bromine), ERF-001M30 (phenoxy resins containing phosphorus), FX-280, FX-293, FX-310 (phenoxy resins containing a fluorene skeleton), and PKHA, PKHB, PKHB+, PKHC, PKHH, PKHJ, PKFE from Gabriel Phenoxies.

[0063] The resin layer (C) formed by the heating process may have the basic nitrogen atom-containing group in the dispersant (b2) or a functional group [X] that remains partially unreacted with the phosphate ester group.

[0064] As mentioned above, the resin layer (C) requires the reaction of the basic nitrogen atom-containing group or phosphate ester group contained in the conductive layer (B) with the functional group [X] contained in the resin layer (C) by heating or other means. However, the resin layer (C) after drying may be completely cured or partially cured.

[0065] The resin layer (C) may be a single layer or may consist of two or more layers. When two or more resin layers (C) are formed, for example, the resin layer (C) in contact with the conductive layer (B) can improve adhesion to the conductive layer (B), while the resin layer (C) in contact with the substrate (D), described later, can improve adhesion to the substrate (D).

[0066] Since the coating of the resin layer (C) will be applied to the surface of the conductive layer (B) formed on the surface of the copper foil (A), it is preferable to incorporate an organic solvent to achieve a viscosity that facilitates coating. Examples of the organic solvent include toluene, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isopropyl alcohol, diacetone alcohol, ethylene glycol, and toluene. These solvents can be used individually or in combination of two or more.

[0067] The amount of the organic solvent used is preferably adjusted as appropriate depending on the coating method used when coating the conductive layer (B) and the desired thickness of the resin layer (C).

[0068] Furthermore, known additives such as film-forming aids, leveling agents, thickeners, water repellents, defoamers, and antioxidants may be added to the resin layer (C) as needed.

[0069] Methods for applying the coating to the resin layer (C) include, for example, gravure printing, microgravure printing, coating, screen printing, roller printing, rotary printing, spray printing, capillary printing, and doctor roll printing.

[0070] A common method for removing the organic solvent contained in the coating layer after applying the resin layer (C) to the surface of the conductive layer (B) formed on the surface of the copper foil (A) is to dry it using a dryer to volatilize the organic solvent. The drying temperature must be set to a temperature that allows the organic solvent to volatilize, does not adversely affect the copper foil (A) such as thermal deformation, and, as described above, allows the functional group [X] contained in the resin layer (C) to react with the basic nitrogen atom-containing group or the phosphate ester group contained in the conductive layer (B).

[0071] The drying temperature of the resin layer (C) is preferably 50°C to 400°C, more preferably 80°C to 300°C, and even more preferably 120°C to 250°C.

[0072] The thickness of the resin layer (C) varies depending on the application, but is preferably within a range that further improves the adhesion between the resin layer (C) and the substrate (D) described later. The thickness of the resin layer (C) is preferably 10 nm to 10 μm, more preferably 50 nm to 1 μm, and even more preferably 50 nm to 500 nm.

[0073] The surface of the resin layer (C) may be pre-treated by a plasma discharge treatment method such as corona discharge treatment, a dry treatment method such as ultraviolet treatment, or a wet treatment method using water, an acidic or alkaline chemical solution, or an organic solvent, if necessary, in order to further improve adhesion with the substrate (D) described later.

[0074] Next, we will explain the base material (D). The substrate (D) is used to form conductive patterns, and therefore needs to be changed depending on the application, such as semiconductor package substrates, flexible printed circuit boards, rigid printed circuit boards, ceramic substrates, glass substrates, silicon wafer substrates, metal substrates, electromagnetic shielding films, and molded circuit boards.

[0075] Examples of materials for the base material (D) include polyimide resin, modified polyimide resin (MPI), polyamide-imide resin, polyamide resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polycarbonate resin, acrylonitrile-butadiene-styrene (ABS) resin, polyarylate resin, polyacetal resin, acrylic resin such as poly(meth)acrylate, polyvinylidene fluoride resin, polytetrafluoroethylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, vinyl chloride resin obtained by graft copolymerization of acrylic resin, polyvinyl alcohol resin, polyethylene resin, polypropylene resin, urethane resin, Examples include cycloolefin resins, polystyrene, liquid crystal polymers (LCP), polyether ether ketone (PEEK) resins, polyphenylene sulfide (PPS), polyphenylene sulfone (PPSU), polyphenylene ether (PPE), bismaleimidotriazine resin (BT resin), fluororesin composite polyimide resins (films in which a fluororesin layer is formed on the surface of a polyimide resin), thermoplastic polyimide resin composite polyimide resins (films in which a thermoplastic polyimide resin layer is formed on the surface of a polyimide resin), cellulose nanofibers, silicon, silicon carbide, gallium nitride, sapphire, ceramics, glass, diamond-like carbon (DLC), alumina, and the like.

[0076] Furthermore, a resin substrate containing a thermosetting resin and an inorganic filler can be suitably used as the base material (D). Examples of the thermosetting resin include epoxy resin, phenolic resin, unsaturated imide resin, cyanate resin, isocyanate resin, benzoxazine resin, oxetane resin, amino resin, unsaturated polyester resin, allyl resin, dicyclopentadiene resin, silicone resin, triazine resin, melamine resin, liquid crystal polymer (LCP), polyether ether ketone (PEEK) resin, polyphenylene sulfide (PPS), polyphenylene sulfone (PPSU), and polyphenylene ether (PPE). Examples of the inorganic filler include silica, alumina, talc, mica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, aluminum borate, and borosilicate glass. These thermosetting resins and inorganic fillers can be used individually or in combination of two or more. The inorganic filler can also be used in powder, flake, or fibrous form. Furthermore, the substrate (D) can be an uncured, semi-cured, or fully cured thermosetting resin. In particular, it is preferable to use an uncured or semi-cured thermosetting resin because it can improve the adhesion between the copper foil on which the conductive layer (B) containing silver (b1) is laminated and the substrate (D) described later.

[0077] The substrate (D) can take any form, including a planar flexible material, a rigid material, or a rigid-flexible material. More specifically, commercially available materials molded into films, sheets, or plates may be used, or materials molded into a planar shape from a solution, melt, or dispersion of the resin may be used. Furthermore, the substrate may be formed by creating the resin material on a conductive material such as metal, or by laminating the resin material on a printed circuit board on which a circuit pattern has been formed.

[0078] For flexible printed circuit boards, polyimide resin, modified polyimide resin (MPI), polytetrafluoroethylene resin, cycloolefin resin, polystyrene, liquid crystal polymer (LCP), polyphenylene sulfide (PPS), fluororesin composite polyimide resin (a film in which a fluororesin layer is formed on the surface of a polyimide resin, or a multilayer film in which polyimide resin and fluororesin are alternately laminated), thermoplastic polyimide resin composite polyimide resin (a film in which a thermoplastic polyimide resin layer is formed on the surface of a polyimide resin), etc., can be used.

[0079] When the substrate (D) is in the form of a film or sheet, the thickness is not particularly limited, but considering flexibility and bendability, it is usually 1 μm to 5,000 μm, more preferably 1 μm to 500 μm, and more preferably 1 μm to 200 μm.

[0080] In the case of rigid printed circuit boards, composite substrates include glass fiber and epoxy resin (glass epoxy resin, FR-4, FR-5), paper and epoxy resin (FR-3), glass nonwoven fabric and epoxy resin (CEM-3), paper, glass nonwoven fabric and epoxy resin (CEM-1), paper and phenolic resin (paper phenolic resin, FR-1, FR-2), glass fiber and PPE resin (e.g., Panasonic's Megtron 6), bismaleid triazine resin (BT resin), and silica and epoxy resin (e.g., Ajinomoto). Materials such as the company's build-up film, polyimide, liquid crystal polymer, polyether ether ketone, polyphenylene sulfide, polystyrene, polycarbonate, polyester resin, polypropylene, polyethylene, acrylic resin, urethane resin, cycloolefin polymer, glass, silicon, silicon carbide, gallium nitride, gallium oxide, sapphire, ceramics, alumina ceramic, alumina, glass, diamond-like carbon, aluminum, stainless steel, copper, silver, gold, iron, nickel, etc. can be used.

[0081] Furthermore, examples of the base material (D) include synthetic fibers such as polyester fibers, polyamide fibers, and polyaramid fibers, inorganic fibers such as carbon fibers, and natural fibers such as cellulose nanofibers.

[0082] The surface of the substrate (D) is preferably smooth in printed circuit boards where high-frequency transmission is required. In fifth-generation mobile communication systems (5G) and millimeter-wave communication, the frequency of the alternating current is high for high-speed communication. As the frequency increases, the skin effect occurs, causing current to flow on the surface layer of the copper wiring. Therefore, if the surface of the copper wiring through which the current flows is rough, the transmission loss increases. For this reason, the surface of the substrate (D) is preferably smooth. The surface roughness (maximum height Sz) measured with a laser microscope is preferably 0.1 μm or more and 2.0 μm or less, more preferably 0.1 μm or more and 1.5 μm or less, and even more preferably 0.1 μm or more and 1.0 μm or less. The surface roughness (maximum height Sz) is measured using the evaluation method described in ISO 25178 and represents the distance from the highest point to the lowest point on the surface.

[0083] Methods for smoothing a substrate (D) include physically smoothing the surface of the substrate (D) and chemically smoothing it. Physical smoothing methods include calendering, cutting, grinding, abrasive polishing, electrical discharge machining, laser processing, and water jet machining, which smooth the surface by passing the substrate (D) between smooth rolls. Chemical smoothing methods include electrolytic polishing and etching polishing.

[0084] Furthermore, if the substrate (D) is an uncured or semi-cured thermosetting resin or thermoplastic resin, a smooth metal foil such as copper foil or aluminum foil, or a smooth heat-resistant film such as polyimide film or fluororesin film can be used as a smoothing treatment substrate. The smooth surface can be bonded to the surface of the substrate (D) by heat and pressure, and then peeled off to transfer the smooth surface to the surface of the substrate (D). In particular, if the substrate (D) is a substrate for a rigid substrate containing a thermosetting resin such as epoxy resin or polyphenylene ether resin, glass fibers, and inorganic fillers, the smooth surface of copper foil can be heat and pressure bonded to the substrate using a press or the like, and then the copper foil can be removed by etching with copper chloride or iron chloride to make the substrate surface smooth. The surface roughness of the smoothing treatment substrate affects the surface roughness of the substrate (D) that is ultimately to be made smooth. Therefore, the surface roughness of the smoothed substrate is preferably smooth, and the surface roughness Sz measured with a laser microscope is preferably 0.1 μm or more and 2.0 μm or less, more preferably 0.1 μm or more and 1.5 μm or less, and even more preferably 0.1 μm or more and 1.0 μm or less. The surface roughness (maximum height Sz) is measured using the evaluation method described in ISO 25178 and represents the distance from the highest point to the lowest point on the surface.

[0085] In a laminate formed by bonding the conductive layer (B) or resin layer (C) to the substrate (D), the surface of the substrate (D) may be surface-treated as needed to further improve the adhesion between the conductive layer (B) or resin layer (C) and the substrate (D). This treatment may involve forming fine irregularities on the substrate (D) without losing its smoothness, or introducing functional groups such as hydroxyl groups, carbonyl groups, or carboxyl groups. Examples of such treatments include plasma discharge treatment such as corona discharge treatment, dry treatment such as ultraviolet treatment, and wet treatment using water, aqueous solutions such as acids and alkalis, or organic solvents.

[0086] Next, a method for laminating the treated copper foil of the present invention onto a substrate (D) will be described. As for the bonding method, a method can be used in which the conductive layer (B) or resin layer (C) surface of the treated copper foil of the present invention is bonded to a substrate (D) using heat and pressure. There are no particular limitations, but for example, a thermal lamination method, a thermal roll transfer method, an in-mold transfer method, a press method, a vacuum press method, etc. can be used.

[0087] When the base material (D) is a flexible material in the form of a roll film, it is preferable to use the heat lamination method or the heat roll transfer method. On the other hand, when the base material (D) is a rigid material, it is often heat-pressed in sheet form, so it is preferable to use the press method or the vacuum press method.

[0088] Regarding the heat-compression bonding conditions, the heating temperature is preferably 50°C to 400°C, more preferably 80°C to 350°C, and even more preferably 100°C to 250°C. The pressure conditions are preferably 0.05 MPa to 35 MPa, more preferably 0.3 MPa to 20 MPa, and even more preferably 0.3 MPa to 10 MPa.

[0089] In the case of heat lamination, the heat-sealing process is performed by the linear pressure of the rolls while the material is being transported, so the process can be completed in less than one second. On the other hand, in the case of press or vacuum press, it is preferable to complete the process in between one second and 200 minutes, and more preferably between 30 seconds and 120 minutes.

[0090] Furthermore, when performing heat-compression bonding, it is preferable to use a vacuum press and perform the heat-compression bonding under vacuum. By performing heat-compression bonding under vacuum, it is possible to suppress lamination defects caused by gas entering between the treated copper foil and the substrate (D) of the present invention. The vacuum conditions are preferably such that the absolute pressure is 100 hPa or less, more preferably 50 hPa or less, and even more preferably 10 hPa or less. It is preferable to perform the heating and pressure conditions under the same conditions as described above.

[0091] The laminate formed by bonding the treated copper foil of the present invention to a substrate (D) can be used as a substrate for circuit formation, and examples of methods for forming circuit patterns include the subtractive method and the semi-additive method.

[0092] The subtractive method described above is a method for forming a desired circuit pattern by forming an etching resist layer of a desired circuit pattern on a pre-fabricated treated copper foil constituting the laminate of the present invention, and then dissolving and removing the copper foil (A) and conductive layer (B) in the portions where the resist has been removed with a chemical solution. As the chemical solution, a chemical solution containing copper chloride, iron chloride, etc., can be used.

[0093] The semi-additive method described above involves removing only the copper foil (A) constituting the pre-fabricated laminate of the present invention to expose the conductive layer (B), performing surface treatment on the outermost conductive layer (B) surface as necessary, forming a plating resist layer on that surface in a shape corresponding to the desired circuit pattern, then forming a copper plating layer by electroless plating, electroplating, or a combination thereof, and finally dissolving and removing the plating resist layer and the conductive layer (B) in contact with it using a chemical solution or the like to form the desired circuit pattern.

[0094] Furthermore, after forming the desired pattern, nickel / gold plating, nickel / palladium / gold plating, or palladium / gold plating may be applied to the circuit pattern as needed, and coverlay film lamination or solder resist layer formation may be performed on the circuit pattern.

[0095] As described above, the treated copper foil in which a conductive layer (B) containing silver (b1) or a conductive layer (B) and a resin layer (C) are laminated on at least one surface of the copper foil (A), and the method for manufacturing the same, as well as the laminate obtained by laminating the treated copper foil, and the method for manufacturing the same, makes it possible to manufacture a laminate with excellent smoothness at the interface between the copper foil and the substrate and high adhesion. Therefore, by using the treated copper foil and laminate of the present invention and applying known patterning methods for copper wiring formation technology, high-density, high-performance semiconductor packages and printed circuit boards can be provided at low cost and in good condition. Thus, the present invention has high industrial applicability in the field of electronics. [Examples]

[0096] The present invention will be described in detail below with reference to examples. However, the present invention is not limited in any way by the following examples.

[0097] [Preparation Example 1: Preparation of copper foil (A)] Copper foil (A) was obtained by plating a base copper foil (untreated electrolytic copper foil, thickness: 18 μm, surface roughness Sz 0.40 μm of the roughened surface) using a plating solution containing nickel sulfate, zinc pyrophosphate, potassium pyrophosphate, 3-aminopropyltrimethoxysilane, and aqueous ammonia (concentration 28 wt%), under the following conditions: plating solution temperature 20°C, current density 1.5 A / dm2, and processing time 5 minutes. The surface roughness Sz of copper foil (A) was 0.41 μm.

[0098] The plating solution was adjusted to the following concentrations. Nickel concentration: 2.5 g / L Zinc concentration: 0.1 g / L Potassium pyrophosphate concentration: 50 g / L Concentration of 3-aminopropyltrimethoxysilane: 1.9 g / L Amount of ammonia solution (28% by weight concentration) added: 25.3 g / L

[0099] [Preparation Example 2: Preparation of coating solution (1) for forming conductive layer (B)] Under a nitrogen atmosphere, a mixture containing 20 parts by mass of methoxypolyethylene glycol (number average molecular weight 2,000), 8.0 parts by mass of pyridine, and 20 ml of chloroform was mixed with a chloroform solution (30 ml) containing 9.6 parts by mass of p-toluenesulfonic acid chloride, which was then added dropwise for 30 minutes while stirring on ice. The mixture was then stirred at a bath temperature of 40°C for 4 hours, and 50 ml of chloroform was mixed in. Next, the obtained product was washed with 100 ml of 5% by mass aqueous hydrochloric acid solution, then with 100 ml of saturated sodium bicarbonate aqueous solution, then with 100 ml of saturated saline solution, dried with anhydrous magnesium sulfate, filtered, concentrated under reduced pressure, washed several times with hexane, filtered, and dried under reduced pressure at 80°C to obtain methoxypolyethylene glycol having p-toluenesulfonyloxy groups.

[0100] 5.39 parts by mass of methoxypolyethylene glycol having a p-toluenesulfonyloxy group, 20 parts by mass of polyethyleneimine (manufactured by Aldrich, molecular weight 25,000), 0.07 parts by mass of potassium carbonate, and 100 ml of N,N-dimethylacetamide were mixed and stirred at 100°C for 6 hours under a nitrogen atmosphere. Next, 300 ml of a mixed solution of ethyl acetate and hexane (volume ratio of ethyl acetate / hexane = 1 / 2) was added, and after vigorous stirring at room temperature, the solid product was filtered. The solid was washed with 100 ml of a mixed solution of ethyl acetate and hexane (volume ratio of ethyl acetate / hexane = 1 / 2), and then dried under reduced pressure to obtain a dispersant (b2), which is a compound in which polyethylene glycol is bonded to polyethyleneimine.

[0101] 138.8 parts by mass of an aqueous solution containing 0.592 parts by mass of the obtained dispersant (b2) was mixed with 10 parts by mass of silver oxide and stirred at 25°C for 30 minutes. Next, 46 parts by mass of dimethylethanolamine was gradually added while stirring, and the mixture was stirred at 25°C for 30 minutes. Subsequently, 15.2 parts by mass of a 10% by mass aqueous solution of ascorbic acid was gradually added while stirring, and stirring was continued for 20 hours to obtain a silver dispersion.

[0102] A mixed solvent of 200 ml of isopropyl alcohol and 200 ml of hexane was added to the obtained silver dispersion and stirred for 2 minutes, then centrifuged at 3000 rpm for 5 minutes. After removing the supernatant, a mixed solvent of 50 ml of isopropyl alcohol and 50 ml of hexane was added to the precipitate and stirred for 2 minutes, then centrifuged at 2000 rpm for 10 minutes. After removing the supernatant, 20 parts by mass of water was added to the precipitate and stirred for 2 minutes to remove the organic solvent under reduced pressure. After adding 10 parts by mass of water and stirring to disperse, the dispersion was left in a -40°C refrigerator overnight to freeze, and then treated in a freeze-dryer (FDU-2200, manufactured by Tokyo Rikakikai Co., Ltd.) for 24 hours to obtain silver (b1) containing a dispersant (b2) consisting of gray-green metallic flake-like lumps.

[0103] The resulting silver (b1) flake-like mass containing the obtained dispersant (b2) was dispersed in a mixed solvent of 45 parts by mass of ethanol and 55 parts by mass of ion-exchanged water to obtain a coating solution (1) for forming a 5% by mass conductive layer (B). The proportion of the dispersant (b2) was calculated from the ash content obtained by heating the obtained coating solution (1) in an electric furnace at 500°C for 1 hour, and it was confirmed that it was 5% by mass relative to 100% by mass of silver solids.

[0104] [Preparation Example 3: Preparation of coating liquid (2) for forming resin layer (C)] 60 parts by mass of phenoxy resin 4250 (bisphenol A / bisphenol F mixed type manufactured by Mitsubishi Chemical Corporation, molecular weight 60,000, solid content 100% by mass), 33 parts by mass of aminotriazine novolac resin ("Phenolite LA-7052" manufactured by DIC Corporation, solid content 60% by mass), 17 parts by mass of epoxy resin ("EPICLON EXA-830CRP" manufactured by DIC Corporation; bisphenol F type epoxy resin, epoxy group equivalent 162 g / equivalent), 3 parts by mass of trimellitic anhydride, 16 parts by mass of "DPE" manufactured by Seika Co., Ltd. as a curing agent, and 0.5 parts by mass of "TBZ" manufactured by Shikoku Chemicals, Inc. as a curing catalyst were mixed, diluted with cyclohexanone to a non-volatile content of 2% by mass, and uniformly mixed to obtain a coating liquid (2) for forming a resin layer (C).

[0105] (Example 1) The copper foil (A) obtained in Preparation Example 1 was coated with the coating solution (1) for forming the conductive layer (B) obtained in Preparation Example 2 using a desktop miniature coater (RK Print Coat Instruments "K Printing Profer"), and dried at 180°C for 1 minute, resulting in a coating of 400 mg / m² by weight on the surface of the copper foil (A). 2 A treated copper foil with a conductive layer (B) formed on it was obtained.

[0106] Next, the side of the treated copper foil with the conductive layer (B) formed on it was placed on a fluororesin sheet ("Nitoflon" manufactured by Nitto Denko Corporation), and pressurized and heated at 200°C, 4 MPa, and for 100 minutes using a vacuum hot press ("Hot Press" manufactured by Japan Steel Works Ltd.). After that, the fluororesin sheet was peeled off to obtain treated copper foil (1) with the conductive layer (B) formed on the copper foil (A).

[0107] The surface resistance of the conductive layer (B) of the treated copper foil (1) was 0.95 Ω / □. The particle sizes obtained by small-angle X-ray scattering of the conductive layer (B) were 27 nm (volume fraction 46%) and 33 nm (volume fraction 54%). Furthermore, the conductivity measured using the balanced disk resonator method on the surface of the treated copper foil with the conductive layer (B) formed was 5.77 × 10⁻¹⁶ at 15.6 GHz. 7 S / m, 54.5GHz, 5.25×10 7 The ratio was S / m. Furthermore, the surface roughness Sz of the copper foil with the conductive layer (B) laminated on it was 0.43 μm.

[0108] (Example 2) Using the same method as in Example 1, the silver layer corresponding to the conductive layer (B) was dried to a weight of 900 mg / m². 2 A copper foil having a conductive layer (B) formed on its surface was obtained by the same method as in Example 1, except that the coating was applied in such a manner.

[0109] Next, a treated copper foil (2) was obtained in which a conductive layer (B) was formed on the copper foil (A) by the same method as in Example 1.

[0110] The surface resistance of the conductive layer (B) of the treated copper foil (2) was 0.49 Ω / □. The particle sizes obtained by small-angle X-ray scattering of the conductive layer (B) were 28 nm (volume fraction 39%) and 70 nm (volume fraction 61%). Furthermore, the conductivity measured using the balanced disk resonator method was 5.10 × 10⁻⁶ at 15.6 GHz. 7 S / m, 3.94 × 10⁻¹⁶ at 54.5GHz 7 The ratio was S / m. Furthermore, the surface roughness Sz of the copper foil with the conductive layer (B) laminated on it was 0.44 μm.

[0111] (Example 3) Using the same method as in Example 1, the silver layer corresponding to the conductive layer (B) was dried to a weight of 1,400 mg / m². 2 A copper foil having a conductive layer (B) formed on its surface was obtained by the same method as in Example 1, except that the coating was applied in such a manner.

[0112] Next, a treated copper foil (3) was obtained in which a conductive layer (B) was formed on the copper foil (A) by the same method as in Example 1.

[0113] The surface resistance of the conductive layer (B) of the treated copper foil (3) was 0.10 Ω / □. The particle sizes obtained by small-angle X-ray scattering of the conductive layer (B) were 29 nm (volume fraction 12%) and 145 nm (volume fraction 88%). Furthermore, the conductivity measured using the balanced disk resonator method was 4.87 × 10⁻¹⁶ at 15.6 GHz. 7 S / m, 4.11×10 at 54.5GHz 7 The ratio was S / m. Furthermore, the surface roughness Sz of the copper foil with the conductive layer (B) laminated on it was 0.45 μm.

[0114] (Example 4) Using the same method as in Example 1, the silver layer corresponding to the conductive layer (B) was dried to a weight of 2,350 mg / m². 2 A copper foil having a conductive layer (B) formed on its surface was obtained by the same method as in Example 1, except that the coating was applied in such a manner.

[0115] Next, a treated copper foil (4) was obtained in which a conductive layer (B) was formed on the copper foil (A) by the same method as in Example 1.

[0116] The surface resistance of the conductive layer (B) of the treated copper foil (4) was 0.08 Ω / □. The particle sizes obtained by small-angle X-ray scattering of the conductive layer (B) were 25 nm (volume fraction 2%) and 440 nm (volume fraction 98%). Furthermore, the conductivity measured using the balanced disk resonator method was 4.10 × 10⁻¹⁶ at 15.6 GHz. 7 S / m, 2.96 × 10⁻¹⁶ at 54.5 GHz 7 The ratio was S / m. Furthermore, the surface roughness Sz of the copper foil with the conductive layer (B) laminated on it was 0.49 μm.

[0117] (Example 5) Using the same method as in Example 1, the silver layer corresponding to the conductive layer (B) was dried to a weight of 4,550 mg / m². 2 A copper foil having a conductive layer (B) formed on its surface was obtained by the same method as in Example 1, except that the coating was applied in such a manner.

[0118] Next, a treated copper foil (5) was obtained in which a conductive layer (B) was formed on the copper foil (A) by the same method as in Example 1.

[0119] The surface resistance of the conductive layer (B) of the treated copper foil (5) was 0.07 Ω / □. The particle sizes obtained by small-angle X-ray scattering of the conductive layer (B) were 25 nm (volume fraction 2%) and 590 nm (volume fraction 98%). Furthermore, the conductivity measured using the balanced disk resonator method was 2.36 × 10⁻¹⁶ at 15.6 GHz. 7 S / m, 1.46 × 10⁻¹⁶ at 54.5 GHz 7 The ratio was S / m. Furthermore, the surface roughness Sz of the copper foil with the conductive layer (B) laminated on it was 0.49 μm.

[0120] (Example 6) The copper foil (A) obtained in Preparation Example 1 is coated with the coating solution (1) for forming the conductive layer (B) obtained in Preparation Example 2 using a desktop miniature coater (RK Print Coat Instruments "K Printing Profer"), and dried at 180°C for 1 minute, resulting in a layer of 400 mg / m² on the surface of the copper foil (A). 2 A copper foil with a conductive layer (B) formed on it was obtained. Next, the coating liquid (2) for forming the resin layer (C) obtained in adjustment example 3 was applied to the surface with the conductive layer (B) using a desktop miniature coater (RK Print Coat Instruments "K Printing Profer") to coat a layer corresponding to the resin layer (C) so that the thickness after drying would be 0.3 μm, and by drying at 180°C for 1 minute, a treated copper foil (6) was obtained in which the conductive layer (B) and the resin layer (C) were sequentially formed on the surface of the copper foil (A).

[0121] The surface resistance of the conductive layer (B) of the treated copper foil (6) was 0.95 Ω / □. The particle sizes obtained by small-angle X-ray scattering of the conductive layer (B) were 28 nm (volume fraction 47%) and 33 nm (volume fraction 53%). Furthermore, the conductivity measured using the balanced disk resonator method was 5.65 × 10⁻¹⁶ at 15.6 GHz. 7 S / m, 54.5GHz, 5.20×10 7 The ratio was S / m. Furthermore, the surface roughness Sz of the copper foil with the conductive layer (B) laminated on it was 0.43 μm.

[0122] (Example 7) Using the same method as in Example 6, the silver layer corresponding to the conductive layer (B) was dried to a weight of 1,400 mg / m². 2 Except for the coating being applied in the same manner as in Example 6, a treated copper foil (7) was obtained in which a conductive layer (B) and a resin layer (C) were sequentially formed on the surface of the copper foil (A).

[0123] The surface resistance of the conductive layer (B) of the copper foil (7) was 0.10 Ω / □. The particle sizes obtained by small-angle X-ray scattering of the conductive layer (B) were 28 nm (volume fraction 14%) and 142 nm (volume fraction 86%). Furthermore, the conductivity measured using the balanced disk resonator method was 4.76 × 10⁻¹⁶ at 15.6 GHz. 7S / m, 4.08 × 10⁻¹⁶ at 54.5GHz 7 The ratio was S / m. Furthermore, the surface roughness Sz of the copper foil with the conductive layer (B) laminated on it was 0.45 μm.

[0124] (Example 8) Using the same method as in Example 6, the silver layer corresponding to the conductive layer (B) was dried to a weight of 2,350 mg / m². 2 Except for the coating being applied in the same manner as in Example 6, a treated copper foil (8) was obtained in which a conductive layer (B) and a resin layer (C) were sequentially formed on the surface of the copper foil (A).

[0125] The surface resistance of the conductive layer (B) of the treated copper foil (8) was 0.08 Ω / □. The particle sizes obtained by small-angle X-ray scattering of the conductive layer (B) were 25 nm (volume fraction 2%) and 445 nm (volume fraction 98%). Furthermore, the conductivity measured using the balanced disk resonator method was 4.13 × 10⁻¹⁶ at 15.6 GHz. 7 S / m, 2.89 × 10⁻¹⁴ at 54.5 GHz 7 The ratio was S / m. Furthermore, the surface roughness Sz of the copper foil with the conductive layer (B) laminated on it was 0.49 μm.

[0126] (Example 9) The side of the treated copper foil (1) with the conductive layer (B) formed on it was bonded to both sides of a prepreg (Panasonic Corporation's "R5670"), and then heat-pressed using a vacuum hot press (Japan Steel Works Ltd.'s "Hot Press") at 200°C, 4 MPa, and for 100 minutes to obtain a laminate (1) in which the copper foil (A) and conductive layer (B) were formed on the prepreg corresponding to the substrate (D). The peel strength of the copper foil in the laminate (1) was 0.31 kN / m.

[0127] Furthermore, the surface resistance of the outermost conductive layer (B) after removing only the copper foil (A) of the laminate (1) by etching was 0.90 Ω / □.

[0128] (Example 10) A laminate (2) was obtained in which copper foil (A) and a conductive layer (B) were formed on a prepreg corresponding to the substrate (D), using the same method as in Example 9, except that treated copper foil (2) was used instead of treated copper foil (1) used in Example 9. The peel strength of the copper foil in the laminate (2) was 0.32 kN / m.

[0129] Furthermore, the surface resistance of the outermost conductive layer (B) after etching away only the copper foil (A) of the laminate (2) was 0.50 Ω / □.

[0130] (Example 11) A laminate (3) was obtained in which copper foil (A) and a conductive layer (B) were formed on a prepreg corresponding to the substrate (D), using the same method as in Example 9, except that copper foil (3) was used instead of the treated copper foil (1) used in Example 9. The peel strength of the copper foil in the laminate (3) was 0.36 kN / m.

[0131] Furthermore, the surface resistance of the outermost conductive layer (B) after removing only the copper foil (A) of the laminate (3) by etching was 0.09 Ω / □.

[0132] (Example 12) A laminate (4) was obtained in which copper foil (A) and a conductive layer (B) were formed on a prepreg corresponding to the substrate (D), using the same method as in Example 9, except that treated copper foil (4) was used instead of treated copper foil (1) used in Example 9. The peel strength of the copper foil in the laminate (4) was 0.39 kN / m.

[0133] Furthermore, the surface resistance of the outermost conductive layer (B) after removing only the copper foil (A) of the laminate (4) by etching was 0.08 Ω / □.

[0134] (Example 13) A laminate (5) was obtained in which copper foil (A) and a conductive layer (B) were formed on a prepreg corresponding to the substrate (D), using the same method as in Example 9, except that treated copper foil (5) was used instead of treated copper foil (1) used in Example 9. The peel strength of the copper foil in the laminate (5) was 0.35 kN / m. Furthermore, the surface resistance of the outermost conductive layer (B) after removing only the copper foil (A) of the laminate (5) by etching was 0.07 Ω / □.

[0135] (Example 14) The side of the treated copper foil (6) with the resin layer (C) formed on it was bonded to both sides of a prepreg (Panasonic Corporation's "R5670"), and then heat-pressed using a vacuum hot press (Japan Steel Works Ltd.'s "Hot Press") at 200°C, 4 MPa, and for 100 minutes to obtain a laminate (6) in which the copper foil (A), conductive layer (B), and resin layer (C) were sequentially formed on the prepreg corresponding to the base material (D). The peel strength of the copper foil in the laminate (6) was 0.43 kN / m.

[0136] Furthermore, the surface resistance of the outermost conductive layer (B) after removing only the copper foil (A) of the laminate (6) by etching was 0.91 Ω / □.

[0137] (Example 15) Except for using copper foil (7) instead of the treated copper foil (6) used in Example 14, a laminate (7) was obtained in which copper foil (A), a conductive layer (B), and a resin layer (C) were sequentially formed on a prepreg corresponding to the substrate (D) using the same method as in Example 14. The peel strength of the copper foil in the laminate (7) was 0.45 kN / m.

[0138] Furthermore, the surface resistance of the outermost conductive layer (B) after removing only the copper foil (A) of the laminate (7) by etching was 0.11 Ω / □.

[0139] (Example 16) Except for using treated copper foil (8) instead of treated copper foil (6) used in Example 14, a laminate (8) was obtained in which copper foil (A), a conductive layer (B), and a resin layer (C) were sequentially formed on a prepreg corresponding to the substrate (D) using the same method as in Example 14. The peel strength of the copper foil in the laminate (8) was 0.52 kN / m.

[0140] Furthermore, the surface resistance of the outermost conductive layer (B) after etching away only the copper foil (A) of the laminate (8) was 0.08 Ω / □.

[0141] (Example 17) Using the treated copper foil (8), a laminate (9) was obtained in which copper foil (A), a conductive layer (B), and a resin layer (C) were sequentially formed on a build-up film (GX-92, manufactured by Ajinomoto Co., Inc., 30 μm thick) corresponding to the substrate (D) by the same method as in Example 14. The peel strength of the copper foil of the laminate (9) according to the method specified in JISC6481 was 0.51 kN / m.

[0142] Furthermore, the surface resistance of the outermost conductive layer (B) after removing only the copper foil (A) of the laminate (9) by etching was 0.09 Ω / □.

[0143] (Example 18) Using the treated copper foil (8), a laminate (10) was obtained in which copper foil (A), a conductive layer (B), and a resin layer (C) were sequentially formed on a polyimide film (Kapton 150EN-C, manufactured by Toray DuPont Co., Ltd.) corresponding to the substrate (D) by the same method as in Example 14. The peel strength of the copper foil of the laminate (10) according to the method specified in JISC6481 was 0.49 kN / m.

[0144] Furthermore, the surface resistance of the outermost conductive layer (B) after removing only the copper foil (A) of the laminate (9) by etching was 0.08 Ω / □.

[0145] (Comparative Example 1) A roughened surface (surface roughness Sz 0.41 μm) of copper foil (Fukuda Metal Foil & Powder Industry Co., Ltd. "CF-T9DA-SV-18" copper foil; thickness 18 μm) was bonded to both sides of a prepreg (Panasonic Corporation "R5670"), and then heat-pressed using a vacuum hot press (Japan Steel Works Ltd. "Hot Press") at 200°C, 4 MPa, for 100 minutes to obtain a laminate (R1) in which copper foil (A) was sequentially formed on the prepreg corresponding to the substrate (D). The peel strength of the copper foil in the laminate (R1) was 0.19 kN / m.

[0146] <Surface resistivity> The surface resistivity was measured using a resistivity meter (Loresta GP, manufactured by Mitsubishi Chemical Analytical Corporation).

[0147] <Average particle size and volume fraction> The average particle size and volume fraction were calculated using the USAX method (2θ = 0 to 4 degrees) with an X-ray diffraction analyzer (SmartLab, manufactured by Rigaku Corporation).

[0148] <Conductivity> Using a network analyzer and a resonator, conductivity at 15.6 GHz and 54.5 GHz was measured using the balanced disk resonator method.

[0149] <Surface roughness> The surface roughness Sz was measured using a laser microscope (Olympus Corporation: OLS-5000).

[0150] Table 1 shows the surface resistivity, average particle size and volume fraction, conductivity, and surface roughness of the conductive layers (B) of copper foils (1) to (8) obtained in Examples 1 to 8.

[0151] [Table 1]

[0152] <Peeling strength of copper foil> The peel strength of the laminates (1) to (10) obtained in Examples 9 to 18 and the laminate (R1) of Comparative Example 1 was measured according to the method compliant with JISC6481. The lead width used for measurement was 1 mm, and the peel angle was 90°. Adhesion was evaluated according to the following criteria. A: The peel strength value is 0.40 kN / m or higher. B: The peel strength value is 0.30 kN / m or more and less than 0.40 kN / m. C: The peel strength value is 0.20 kN / m or more and less than 0.30 kN / m. D: The peel strength value is less than 0.20 kN / m.

[0153] Table 2 shows the evaluation results of the adhesion of the copper foil to the laminates (1) to (10) obtained in Examples 9 to 18 and to the laminate (R1) of Comparative Example 1.

[0154] [Table 2]

[0155] The laminates (1) to (10) obtained in Examples 9 to 18, which were formed by laminating the copper foils (1) to (8) obtained in Examples 1 to 8, which are the copper foils of the present invention, onto a substrate (D), were confirmed to have sufficiently high adhesion.

[0156] On the other hand, it was confirmed that the laminate (R1) obtained in Comparative Example 1 had insufficient adhesion.

Claims

1. A treated copper foil in which a conductive layer (B) containing silver (b1) is laminated on at least one surface of a copper foil (A).

2. The treated copper foil according to claim 1, characterized in that the conductive layer (B) further contains a dispersant (b2).

3. The treated copper foil according to claim 2, characterized in that the dispersant (b2) has a basic nitrogen atom-containing group.

4. The treated copper foil according to any one of claims 1 to 3, characterized in that the surface resistivity of the conductive layer (B) containing silver (b1) is 0.01 Ω / □ or more and 3.00 Ω / □ or less.

5. The treated copper foil according to any one of claims 1 to 3, characterized in that the silver (b1) forming the conductive layer (B) is a particle with a volume fraction of 50% or more obtained by small-angle X-ray scattering and a particle size of 30 nm to 1000 nm.

6. On the surface on which the conductive layer (B) is formed, the conductivity at 15.6 GHz, measured using the balanced disk resonator method, was 2.0 × 10⁻⁶. ７ S / m or more 6.0×10 ７ The conductivity is less than or equal to S / m, and the conductivity at 54.5 GHz is 1.3 × 10⁻⁶. ７ S / m or more 5.5×10 ７ The treated copper foil according to any one of claims 1 to 3, characterized in that it is S / m or less.

7. The treated copper foil according to any one of claims 1 to 3, characterized in that the copper foil (A) on which the conductive layer (B) is laminated has a surface roughness Sz of the surface on the conductive layer (B) side of 0.1 μm or more and 2.0 μm or less.

8. The conductive layer (B) is 300 mg / m². ２ 10,000mg / m or more ２ The treated copper foil according to any one of claims 1 to 3, characterized in that it is formed with the following weights.

9. The treated copper foil according to any one of claims 1 to 3, characterized in that a resin layer (C) is further laminated on the conductive layer (B).

10. The treated copper foil according to claim 9, characterized in that the resin layer (C) is a resin layer (C) containing a compound (c1) having a functional group [X].

11. The treated copper foil according to claim 10, characterized in that the functional group [X] is one or more functional groups selected from epoxy groups, carboxylic acid groups, carboxylic anhydride groups, keto groups, alkylolamide groups, isocyanate groups, vinyl groups, alkyl halide groups, acryloyl groups, cyanamide groups, carbamide groups, and acyl halide groups.

12. The treated copper foil according to claim 9, characterized in that the thickness of the resin layer (C) is 0.01 μm or more and 10 μm or less.

13. A laminate in which the conductive layer (B) side of the treated copper foil according to claim 1 is laminated on at least one surface of a substrate (D) in such a manner.

14. A laminate in which the resin layer (C) side of the treated copper foil according to claim 9 is laminated on at least one surface of a substrate (D) in contact with it.

15. The laminate according to claim 13, characterized in that the base material (D) is an insulating resin base material.

16. The laminate according to claim 14, characterized in that the base material (D) is an insulating resin base material.

17. The laminate according to claim 13, characterized in that the peel strength of the treated copper foil in the laminate according to the method specified in JIS C6481 is 0.4 kN / m or more.

18. The laminate according to claim 14, characterized in that the peel strength of the treated copper foil in the laminate according to the method specified in JIS C6481 is 0.4 kN / m or more.

19. The laminate according to claim 13, characterized in that when the copper foil (A) is removed from the laminate, the surface resistivity of the conductive layer (B) on the surface where the copper foil (A) was removed is 0.01 Ω / □ or more and 3.00 Ω / □ or less.

20. The laminate according to claim 14, characterized in that when the copper foil (A) is removed from the laminate, the surface resistivity of the conductive layer (B) on the surface where the copper foil (A) was removed is 0.01 Ω / □ or more and 3.00 Ω / □ or less.

21. Step 1 for manufacturing treated copper foil, in which a conductive layer (B) containing silver (b1) is laminated onto at least one surface of copper foil (A), Step 2 involves overlapping the conductive layer (B) side of the treated copper foil with the substrate (D) and heat-pressing the entire assembly. A method for manufacturing a laminate according to claim 13, characterized by having the following features.

22. Step 1 for manufacturing treated copper foil, in which a conductive layer (B) containing silver (b1) and a resin layer (C) are sequentially laminated on at least one surface of a copper foil (A), Step 2 involves overlapping the resin layer (C) side of the treated copper foil with the substrate (D) and heat-pressing the entire assembly. A method for manufacturing a laminate according to claim 14, characterized by having the following features.

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