JP7601400B2 - Composite copper components treated with silane coupling agents - Google Patents

Description

The present invention relates to a composite copper component treated with a silane coupling agent.

Copper foil used in printed wiring boards is required to have good adhesion to the resin substrate. In order to improve this adhesion, a method has been used in which the surface of the copper foil is roughened by etching or the like, thereby increasing the mechanical adhesive strength by the so-called anchor effect. On the other hand, from the viewpoint of increasing the density of printed wiring boards and transmission loss in the high frequency band, flattening of the copper foil surface has become necessary. In order to meet these conflicting requirements, a copper surface treatment method has been developed that performs an oxidation process and a reduction process (WO 2014/126193). In this method, the copper foil is preconditioned, immersed in a chemical solution containing an oxidizing agent to oxidize the copper foil surface and form copper oxide irregularities, and then immersed in a chemical solution containing a reducing agent to reduce the copper oxide, thereby adjusting the surface irregularities and adjusting the surface roughness. Other methods for improving adhesion in copper foil treatment using oxidation/reduction include a method of adding surface active molecules in the oxidation step (JP Patent Publication No. 2013-534054) and a method of forming a protective film on the surface of copper foil using an aminothiazole-based compound or the like after the reduction step (JP Patent Publication No. 8-97559).

Furthermore, in order to increase the adhesion between the copper foil and the insulating resin substrate, a silane coupling agent treatment was also used to increase the chemical adhesive strength.
Silane coupling agents have the following chemical structure:
X-Si(OR) ₃
(X: a reactive organic functional group such as a vinyl group, an epoxy group, an amino group, a methacryl group, or a mercapto group, which chemically bonds with the organic resin in the resin substrate;
-OR is an alkoxy group such as a methoxy group, an ethoxy group, a dialkoxy group, or a trialkoxy group, which hydrolyzes to generate a silanol group (SiOH) and bond to inorganic materials such as copper foil.
It is expressed as:

In the case of a copper foil that has been roughened, it is known that the optimum amount of silane coupling agent varies depending on the method of roughening.
Patent Document 4 describes that the silane coupling agent is preferably attached at 0.15 to 20.0 mg/m ² (Si equivalent), and that if it is less than 0.15 mg/m ² , it is not possible to improve the adhesion between the base resin and the surface-treated copper foil. However, Patent Document 5 describes that the silane coupling agent is preferably attached at 0.03 to 3.00 mg/m ² (Si equivalent), and Patent Document 6 describes that the amount of silane coupling agent present on the roughened surface is preferably 0.05 mg/m ² or more and less than 1.5 mg/m ² in Si equivalent.
The optimum amount of silane coupling agent depends not only on the roughness of the surface to which it is applied, but also on the type of metal laminated on the copper foil surface.For example, WO 2006/134868 describes that the adhesion efficiency of the tin plating layer and the silane coupling agent layer is excellent, and the silane coupling agent is applied on the tin plating layer, whereas in Japanese Patent 6248231, the silane coupling agent is applied to a surface (i.e. pure copper) that has been roughened by electrolytic deposition of copper particles, or a surface that has been electrolytically plated with nickel, zinc, chromium, etc., on the surface, and in WO 2017/099094, the surface that has been roughened by electrolytic deposition of molybdenum particles is nickel-plated, and then treated with the silane coupling agent.

The inventors of the present application had also developed a composite copper foil in which an oxidation-treated copper foil was plated with nickel by electrolytic plating, but the surface roughness and composition of the composite copper foil were different from those of conventional copper foils, and the optimal amount of silane coupling agent to be applied was unknown (WO 2019/093494).

The present invention provides a composite copper foil treated with a silane coupling agent.

As a result of extensive research, the inventors of the present application have succeeded in producing a composite copper component that has excellent mechanical and chemical adhesion to a resin substrate by precipitating needle-shaped copper oxide through an oxidation process, then electrolytically plating the roughened copper component to form a nickel layer on the roughened surface, and coating the surface with the nickel layer with a silane coupling agent.

The present invention includes the following aspects:
[1] A composite copper member having a layer containing needle-shaped copper oxide on at least a part of the surface of a copper member, a nickel layer on the copper oxide layer, and a silane coupling agent layer on the surface on which the nickel layer is formed, wherein the adhesion amount of the silane coupling agent layer is 7 μg/dm2 ^or more and 900 μg/dm2 or ^less (Si converted weight per unit area of the copper member).
[2] The BET surface area ratio of the surface on which the silane coupling agent layer is formed (surface area of the surface on which the silane coupling agent layer is formed / plan view area of the copper member on which the silane coupling agent layer is formed, calculated by the BET method) is 3 or more and 20 or less. The composite copper member according to [1].
[3] The composite copper member according to [1] or [2], wherein the nickel layer has a thickness of 0.5 mg/ ^dm2 or more and 25 mg/dm2 ^or less (nickel weight per unit area of the copper member).
[4] The composite copper member according to any one of [1] to [3], wherein the surface on which the silane coupling agent layer is formed has an Ra of 0.02 μm or more and 0.17 μm or less.
[5] The composite copper member according to any one of [1] to [4], wherein the Rz of the surface on which the silane coupling agent layer is formed is 0.2 μm or more and 1.5 μm or less.
[6] The composite copper member according to any one of [1] to [5], wherein the surface on which the silane coupling agent layer is formed has a BET surface area ratio/Rz value of 4 μm ⁻¹ or more.
[7] The silane coupling agent is represented by the following formula:
Y-Si(OR) ₃
(Y is selected from the group consisting of vinyl, epoxy, amino, methacryl, mercapto, 3-mercaptopropyl, 3-aminopropyl, 3-mercaptopropyl, 2-(3,4-epoxycyclohexyl)ethyl, 3-methacryloxypropyl, 3-isocyanatopropyl, 3-ureidopropyl, and 3-acryloxypropyl groups;
The composite copper member according to any one of [1] to [6], comprising a compound represented by the formula (I)-OR is an alkoxy group.
[8] A laminate in which a resin base material is laminated on the silane coupling agent layer of the composite copper member according to any one of [1] to [7].
[9] A printed wiring board comprising the laminate according to [8].
[10] The composite copper member according to any one of [1] to [7], wherein the copper member is a copper foil.
[11] A negative electrode current collector comprising the composite copper member according to [10].

[12] A method for producing a composite copper part treated with a silane coupling agent, comprising the steps of:
a first step of forming a copper oxide layer having an average thickness of 400 nm or less and a fine uneven shape on at least a part of a surface of a copper member by oxidation treatment;
a second step of forming a nickel layer on the copper oxide layer by electrolytic plating;
A third step of coating the surface on which the nickel layer is formed with a silane coupling agent in an amount of 7 μg/dm ² or more and 900 μg/dm ² or less (weight in terms of Si per unit area of the copper member),
Manufacturing method.
[13] The manufacturing method according to [12], wherein the surface on which the copper oxide layer is formed after the first step has an Ra of 0.035 or more and 0.15 or less.
[14] The method according to [12] or [13], wherein the Rz of the surface on which the copper oxide layer is formed after the first step is 0.25 or more and 1.45 or less.
[15] The manufacturing method according to any one of [12] to [14], wherein the current density of the electrolytic plating treatment in the second step is 5 A/ ^dm2 or less.
[16] The manufacturing method according to any one of [12] to [15], wherein the thickness of the nickel layer is 0.5 mg/dm2 or ^more and 25 mg/dm2 ^or less (nickel weight per unit area of the copper member).
[17] The silane coupling agent is represented by the following formula:
X-Si(OR) ₃
(X is selected from the group consisting of vinyl, epoxy, amino, methacryl, mercapto, 3-mercaptopropyl, 3-aminopropyl, 3-mercaptopropyl, 2-(3,4-epoxycyclohexyl)ethyl, vinyl, 3-methacryloxypropyl, 3-isocyanatopropyl, 3-ureidopropyl, and 3-acryloxypropyl groups;
The method according to any one of [12] to [16], comprising a compound represented by the formula (I) (-OR is an alkoxy group).
[18] The method according to any one of [12] to [17], wherein the Ra of the surface coated with the silane coupling agent after the third step is 0.02 μm or more and 0.17 μm or less.
[19] The method according to any one of [12] to [18], wherein the Rz of the surface coated with the silane coupling agent after the third step is 0.2 μm or more and 1.5 μm or less.
[20] The method according to any one of [12] to [19], wherein the BET surface area ratio of the surface coated with the silane coupling agent after the third step is 3 or more and 20 or less.
[21] The method according to any one of [12] to [20], wherein the BET surface area ratio/Rz value of the surface coated with the silane coupling agent after the third step is 4 μm ⁻¹ or more.
[22] A method for producing a laminate, comprising a step of thermocompression bonding a resin substrate to a copper member treated with a silane coupling agent produced by the method for producing a laminate according to any one of [12] to [21].
[23] The method according to any one of [12] to [21], wherein the copper member is a copper foil.
[24] A method for producing a secondary battery, comprising a step of coating and supporting a conductive active material on a composite copper member treated with a silane coupling agent produced by the method for producing a secondary battery according to [23].
==Cross references to related literature==
This application claims priority based on Japanese Patent Application No. 2019-236800, filed on December 26, 2019, the basic application of which is incorporated herein by reference.

FIG. 1 shows cross-sectional images (magnification: 50,000 times) of Example 1 and Comparative Example 10 observed with a scanning electron microscope (SEM).

The preferred embodiment of the present invention will be described in detail below with reference to the attached drawings, but is not necessarily limited thereto. The objectives, features, advantages, and ideas of the present invention will be clear to those skilled in the art from the description in this specification, and those skilled in the art will be able to easily reproduce the present invention from the description in this specification. The embodiments and specific examples of the invention described below show preferred embodiments of the present invention, and are shown for illustrative or explanatory purposes, and do not limit the present invention thereto. It will be clear to those skilled in the art that various modifications and alterations can be made based on the description in this specification within the intent and scope of the present invention disclosed in this specification.

==Method for manufacturing composite copper member treated with silane coupling agent==
One embodiment of the present invention is a method for producing a composite copper member treated with a silane coupling agent, the method comprising a first step of precipitating needle-like copper oxide on a copper foil surface by oxidation treatment to form a copper oxide layer having a fine uneven shape, a second step of forming a nickel layer on the copper oxide layer by electrolytic plating treatment, and a third step of coating the surface on which the nickel layer has been formed with a silane coupling agent.
The copper member is a material that contains Cu as a main component and is a part of the structure, and includes, but is not limited to, copper foil such as electrolytic copper foil, rolled copper foil, and copper foil with a carrier, copper wire, copper plate, copper lead frame, copper powder, etc. Those that can be electroplated are preferable.
The copper foil includes copper foils containing copper as a main component, such as electrolytic copper foils, rolled copper foils, and copper foils with carriers, and has a thickness of 0.1 μm to 100 μm, and more preferably 0.5 μm to 50 μm.
The copper plate refers to a plate-like material whose main component is copper and whose thickness exceeds 100 μm. Although not particularly limited, the thickness is preferably 1 mm or more, 2 mm or more, or 10 mm or more, and is preferably 10 cm or less, 5 cm or less, or 2.5 cm or less.
The copper member is preferably a copper foil made of pure copper having a Cu purity of 95% by mass or more, 99% by mass or more, or 99.9% by mass or more, more preferably made of tough pitch copper, deoxidized copper, or oxygen-free copper, and even more preferably made of oxygen-free copper having an oxygen content of 0.001% by mass to 0.0005% by mass.

In the first step, the copper foil is oxidized to precipitate needle-shaped copper oxide, forming a copper oxide layer with a fine uneven shape. The method of formation is not particularly limited, but it may be formed using an oxidizing agent, or may be formed by heat treatment or anodization. A roughening treatment step such as etching is not necessary before this oxidation step, but may be performed. An alkali treatment may be performed to prevent the introduction of acid into the degreasing and cleaning step or the oxidation step. The method of alkali treatment is not particularly limited, but it is preferable to treat with an alkali aqueous solution of 0.1 to 10 g/L, more preferably 1 to 2 g/L, such as a sodium hydroxide aqueous solution, at 30 to 50°C for about 0.5 to 2 minutes.

The oxidizing agent is not particularly limited, and for example, an alkaline aqueous solution containing hypochlorite (e.g., sodium salt or potassium salt), chlorite, chlorate, perchlorate, etc. Various additives (e.g., phosphates such as trisodium phosphate dodecahydrate) and surface active molecules may be added to the oxidizing agent to adjust the precipitation of copper oxide.
Surface active molecules include porphyrins, porphyrin macrocycles, expanded porphyrins, ring-contracted porphyrins, linear porphyrin polymers, porphyrin sandwich coordination complexes, porphyrin arrays, silanes, tetraorgano-silanes, aminoethyl-aminopropyl-trimethoxysilane, 3-aminopropyl)trimethoxysilane, 1-[3-(trimethoxysilyl)propyl]urea, (3-aminopropyl)triethoxysilane, (3-glycidyloxypropyl)trimethoxysilane, (3-chloropropyl)trimethoxysilane, and 1-[3-(trimethoxysilyl)propyl]urea. Examples include silane, (3-glycidyloxypropyl)trimethoxysilane, dimethyldichlorosilane, 3-(trimethoxysilyl)propyl methacrylate, ethyltriacetoxysilane, triethoxy(isobutyl)silane, triethoxy(octyl)silane, tris(2-methoxyethoxy)(vinyl)silane, chlorotrimethylsilane, methyltrichlorosilane, silicon tetrachloride, tetraethoxysilane, phenyltrimethoxysilane, chlorotriethoxysilane, ethylenetrimethoxysilane, amines, and sugars.
As an example of the oxidation treatment liquid, an aqueous solution containing 30 g/L or more and 250 g/L or less of sodium chlorite, 8 g/L or more and 40 g/L or less of potassium hydroxide, and 0.5 g/L or more and 2 g/L or less of 3-glycidyloxypropyltrimethoxysilane can be used.

The oxidation reaction conditions are not particularly limited, but the liquid temperature of the oxidizing agent is preferably 40 to 95°C, and more preferably 45 to 80°C. The reaction time is preferably 0.5 to 30 minutes, and more preferably 1 to 10 minutes.

In the first step, the oxide layer formed by the oxidation treatment may be dissolved with a solvent to adjust the unevenness of the oxide layer surface.

The dissolving agent used in this process is not particularly limited, but is preferably a chelating agent, particularly a biodegradable chelating agent, and examples thereof include ethylenediaminetetraacetic acid, diethanolglycine, tetrasodium L-glutamic acid diacetate, ethylenediamine-N,N'-disuccinic acid, sodium 3-hydroxy-2,2'-iminodisuccinate, trisodium methylglycine diacetate, tetrasodium aspartic acid diacetate, disodium N-(2-hydroxyethyl)iminodiacetate, and sodium gluconate.

The pH of the dissolving agent is not particularly limited, but it is preferable that it is alkaline, more preferably pH 8 to 10.5, even more preferably pH 9.0 to 10.5, and even more preferably pH 9.8 to 10.2.

In addition, in the first step, the copper oxide layer formed on the copper member may be reduced using a chemical solution containing a reducing agent (reducing chemical solution) to adjust the number and height of the protrusions.

The reducing agent may be DMAB (dimethylamine borane), diborane, sodium borohydride, hydrazine, etc. The reducing solution is a liquid containing a reducing agent, an alkaline compound (sodium hydroxide, potassium hydroxide, etc.), and a solvent (pure water, etc.).

In the first step, the thickness of the copper oxide layer is set to 400 nm or less on average. Preferably, the thickness is set to 200 nm or less on average, more preferably, 160 nm or less on average, or 90 nm or less on average. Furthermore, the thickness of the copper oxide layer is preferably set to 20 nm or more on average, more preferably, 30 nm or more on average, and even more preferably, 40 nm or more on average. The ratio of the area where the thickness of the copper oxide layer is 400 nm or less is not particularly limited, but it is preferable that 50% or more is 400 nm or less, more preferably, 70% or more is 400 nm or less, even more preferably, 90% or more is 400 nm or less, even more preferably, 95% or more is 400 nm or less, and even more preferably, almost 100% is 400 nm or less.
The thickness ratio of the copper oxide layer can be calculated, for example, by a continuous electrochemical reduction assay (SERA) at 10 measurement points in an area of 10×10 cm.

最大高さ粗さ（Ｒｚ）とは基準長さｌにおいて、輪郭曲線（ｙ＝Ｚ（ｘ））の山高さＺｐの最大値と谷深さＺｖの最大値の和を表す。
表面粗さＲａ、ＲｚはＪＩＳ Ｂ ０６０１：２００１（国際基準ＩＳＯ４２８７－１９９７準拠）に定められた方法により算出できる。 The arithmetic mean roughness (Ra) of the copper oxide layer is preferably 0.035 μm or more, more preferably 0.038 μm or more, and is preferably 0.20 μm or less, more preferably 0.060 μm or less.
The maximum height roughness (Rz) of the copper oxide layer is preferably 0.2 μm or more, more preferably 0.25 μm or more, and is preferably 1.45 μm or less, more preferably 0.50 μm or less.
The arithmetic mean roughness (Ra) is the average of the absolute values of Z(x) (i.e., the height of the peaks and the depth of the valleys) in the profile curve (y = Z(x)) expressed by the following formula over a reference length l.

The maximum height roughness (Rz) represents the sum of the maximum peak height Zp and the maximum valley depth Zv of the profile curve (y=Z(x)) over a reference length l.
The surface roughness Ra and Rz can be calculated by the method defined in JIS B 0601:2001 (based on the international standard ISO 4287-1997).

In the second step, the copper oxide layer formed in the first step is subjected to electrolytic plating to form a nickel layer. The nickel layer is formed by electrolytic plating. The nickel content in the nickel layer is preferably 90% by weight or more, 95% by weight or more, 98% by weight or more, 99% by weight or more, or 99.9% by weight or more.
The average thickness of the nickel layer formed by electrolytic plating, expressed as the weight of nickel per unit area of the copper foil on which the nickel layer is formed (the area in plan view of the copper foil in the case of single-sided plating, and twice the area in plan view of the copper foil in the case of double-sided plating), is preferably 0.5 mg/ ^dm2 , 1.0 mg/ ^dm2 , 1.5 mg/ ^dm2 , 2.0 mg/ ^dm2 , 3.0 mg/ ^dm2 , 4.0 ^mg / ^dm2 , 5.0 mg/ ^dm2 , 6.0 mg/dm2, or 7.0 mg/ ^dm2 or more, and preferably 25.0 mg/ ^dm2 , 20.0 mg/ ^dm2 , 15.0 mg/ ^dm2 , 10.0 mg/ ^dm2 , 9.0 mg/ ^dm2 , or 9.0 mg/ ^dm2 or less.
The plan view area of a copper foil is equal to the surface area of a given area when the surface of that area is flat, and corresponds to the defined area in the "developed area ratio (sdr) (ISO 25178)."
The average thickness of the nickel layer can be calculated by dissolving the nickel forming the nickel layer in an acidic solution, measuring the amount of nickel by ICP analysis, and dividing the measured amount by the unit area of the copper foil on which the nickel layer is formed. Alternatively, the copper foil having the nickel layer itself can be dissolved, and only the amount of nickel forming the nickel layer can be detected and measured to calculate the average thickness of the nickel layer.

In electrolytic plating, an electric charge is required even to partially reduce the oxide in the oxide layer. Therefore, when nickel plating is applied to copper foil, in order to keep the thickness within a preferred range, it is preferable to apply an electric charge of 15 C/dm2 ^{or more} and 90 C/dm2 or ^less per area of the copper foil to be electrolytically plated.
The current density is preferably 5 A/ ^dm2 or less. If the current density is too high, plating may concentrate on the convex parts, making uniform plating difficult. The current may be changed until the oxide of the copper oxide layer is partially reduced and during plating. The current is appropriately adjusted to a predetermined thickness depending on the metal to be coated.
As a supplying agent for plating ions, for example, nickel sulfate, nickel sulfamate, nickel chloride, nickel bromide, etc. can be used.
Examples of other additives that may be used include pH buffers and gloss agents, such as boric acid, nickel acetate, citric acid, sodium citrate, ammonium citrate, potassium formate, malic acid, sodium malate, sodium hydroxide, potassium hydroxide, sodium carbonate, ammonium chloride, sodium cyanide, potassium sodium tartrate, potassium thiocyanate, sulfuric acid, hydrochloric acid, potassium chloride, ammonium sulfate, ammonium chloride, potassium sulfate, sodium sulfate, sodium thiocyanate, sodium thiosulfate, potassium bromate, potassium pyrophosphate, ethylenediamine, nickel ammonium sulfate, sodium thiosulfate, hydrofluoric acid, sodium silicofluoride, strontium sulfate, cresol sulfonic acid, β-naphthol, saccharin, 1,3,6-naphthalene trisulfonic acid, naphthalene (di, tri), sodium sulfonate, sulfonamide, and sulfinic acid.
In nickel plating, the bath composition preferably contains, for example, nickel sulfate (100 g/L or more and 350 g/L or less), nickel sulfamate (100 g/L or more and 600 g/L or less), nickel chloride (0 g/L or more and 300 g/L or less), or a mixture thereof, but may also contain additives such as sodium citrate (0 g/L or more and 100 g/L or less) or boric acid (0 g/L or more and 60 g/L or less).

In the third step, the surface after the electrolytic plating is treated with a silane coupling agent. The silane coupling agent used is preferably one having 2 or 3 hydrolyzable groups, and the hydrolyzable groups are preferably methoxy or ethoxy groups.
Although there are no particular limitations, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-ureidopropyltrialkoxysilane, 3-acryloxypropyltrimethoxysilane, and the like can be used.
The silane coupling agent treatment can be carried out by applying or spraying a solution in which the silane coupling agent is dispersed in water or an organic solvent, and allowing it to be adsorbed. The solution in which the silane coupling agent is dispersed in water or an organic solvent is not particularly limited, but is preferably 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or 9% or more by weight, and preferably 20%, 15%, or 10% or less by weight.
After the adsorption, the silane coupling agent treatment is completed by drying. The temperature and time for drying are not particularly limited as long as the water or organic solvent as the solvent is completely evaporated, but drying at 70° C. for 1 minute or more is preferable, drying at 100° C. for 1 minute or more is more preferable, and drying at 110° C. for 1 minute or more is even more preferable.

The arithmetic mean roughness (Ra) of the surface on which the coupling agent layer is formed after the coupling agent treatment is preferably 0.01 μm, 0.02 μm, 0.03 μm or 0.04 μm or more, and more preferably 0.20 μm, 0.15 μm, 0.10 μm or 0.060 μm or less.
The maximum height roughness (Rz) of the surface on which the coupling agent layer is formed after the coupling agent treatment is preferably 0.2 μm, 0.3 μm or 0.4 μm or more, and is preferably 1.5 μm, 1.4 μm, 1.3 μm, 1.2 μm, 1.1 μm, 1.0 μm, 0.50 μm, 0.40 μm or 0.30 μm or less.
In addition, the change in surface roughness, which is expressed as the ratio of Ra after oxidation treatment to Ra after coupling agent treatment (Ra after oxidation treatment/Ra after coupling agent treatment), is preferably 0.7 to 1.3, and the ratio of Rz after oxidation treatment to Rz after coupling agent treatment (Rz after oxidation treatment/Rz after coupling agent treatment) is preferably 0.8 to 1.2. Since the coupling agent layer is extremely thin, the closer this ratio is to 1, the more uniform and even the thickness of the nickel layer formed by electrolytic plating is.

By carrying out the first to third steps, a composite copper foil can be produced that has a layer containing needle-shaped copper oxide on at least a portion of the surface of the copper foil, a nickel layer laminated on the layer containing copper oxide, and a silane coupling agent layer on the surface on which the nickel layer is laminated.

==Composite copper member having silane coupling agent layer==
One embodiment of the present invention is a composite copper member having a layer containing needle-shaped copper oxide on at least a portion of the surface of a copper member, a nickel layer laminated on the layer containing copper oxide, and a silane coupling agent layer on the surface on which the nickel layer is laminated.

The amount of the silane coupling agent layer, expressed as the weight of Si atoms per unit area of the copper foil (planar area of the copper foil in the case of single-sided treatment, planar area of the copper foil x 2 in the case of double-sided treatment) on the surface on which the silane coupling agent layer is formed, is preferably 5 μg/dm ² , 6 μg/dm ² , 7 μg/dm ² , 8 μg/dm ² , 9 μg/dm ^{2 , 10 μg/dm 2 ,} 15 μg/dm ² , 20 μg/dm ² , 30 μg/dm ² , 40 μg/dm ² , 50 μg/dm ² or 60 μg/dm ² or more, and more preferably 900 μg/dm ² , 700 μg/dm ² , 500 μg/dm ² , 400 μg/dm ² , 300 μg/dm ^{2 .} , 200 g/dm ² , 100 μg/dm ² , 70 μg/dm ² , 60 μg/dm ² , or 50 μg/dm ² or less.
The amount of the silane coupling agent layer can be calculated by dissolving the nickel layer with the silane coupling agent layer formed on its surface in an acidic solution, measuring the amount of Si atoms by ICP analysis, and dividing the measured amount by the unit area of the copper foil. Alternatively, the composite copper foil with the silane coupling agent layer itself can be dissolved, and only the amount of Si atoms forming the silane coupling agent layer can be detected and measured to calculate the amount of the silane coupling agent layer.

The surface area is preferably calculated by the BET method, but is not limited to this method. For example, the surface area can be calculated by image processing such as three-dimensional image analysis. Two-dimensional observation images of the copper foil are continuously observed, and the observation images are reconstructed in three dimensions. For observation, a scanning electron microscope (SEM), a transmission electron microscope (TEM), a confocal microscope, etc. may be used. When using an SEM, processing is performed using a FIB (focused ion beam), cross-sectional observation of the entire processed copper foil is performed, and the observation images are accumulated. When using a TEM, an electron beam is irradiated onto the continuously tilted copper foil, and successive tilt images (two-dimensional projection images of the mass density distribution) at each angle are captured. After aligning the successive tilt images, a three-dimensional image is constructed by Fourier transform and inverse Fourier transform.

The BET specific surface area refers to the sum of the surface areas per mass of solid particles calculated by the gas adsorption method (BET method), in which gas molecules such as nitrogen ( _N2 ), argon (Ar), krypton (Kr), and carbon monoxide (CO) are adsorbed onto solid particles and the specific surface area of the solid particles is measured from the amount of adsorbed gas molecules.
The method for measuring the BET specific surface area includes the multi-point krypton gas adsorption BET method, the single-point nitrogen adsorption method, etc. In particular, when measuring a fine surface area, krypton gas is preferred in terms of the saturated vapor pressure.
The total surface area of the composite copper foil can be calculated by (BET specific surface area) x (mass of copper foil used).

（２）片面処理した銅箔の場合

で算出することができる。 The BET surface area ratio can be expressed as (the surface area of the surface on which the silane coupling agent layer is formed, calculated by the BET method)/(the plan view area of the copper foil on which the silane coupling agent layer is formed).
In the copper foil used in the present invention, the surface area of the copper foil side portion can be ignored, so the BET surface area ratio is
(1) In the case of copper foil treated on both sides

(2) In the case of copper foil treated on one side

It can be calculated as follows.

（２）片面処理した銅板の場合

で算出することができる。
シランカップリング剤層が形成された表面のＢＥＴ表面積比は、３以上、４以上、５以上、６以上、７以上、８以上、９以上又は１０以上が好ましく、２０以下、１５以下、１４以下、１３以下、１２以下又は１１以下が好ましい。 In the case of a plate having a thickness of 100 μm or more, such as a copper plate, the surface area of the side surface cannot be ignored.
The BET surface area ratio when the thickness is 100 μm or more is
(1) In the case of copper plates treated on both sides

(2) In the case of copper sheets treated on one side

It can be calculated as follows.
The BET surface area ratio of the surface on which the silane coupling agent layer is formed is preferably 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, or 10 or more, and is preferably 20 or less, 15 or less, 14 or less, 13 or less, 12 or less, or 11 or less.

The BET surface area ratio/Rz value of the surface on which the silane coupling agent layer is formed is preferably 4 μm ⁻¹ or more, 5 μm ⁻¹ or more, 10 μm ⁻¹ or more, 15 μm ⁻¹ or more, or 20 μm ⁻¹ or more, and is preferably 35 μm ⁻¹ or less, 30 μm ⁻¹ or less, or 25 μm ⁻¹ or less.

==Method of using a composite copper member having a silane coupling agent layer==
The composite copper member treated with the silane coupling agent according to the present invention can be used as a copper foil for use in a printed wiring board or a copper foil for a LIB negative electrode current collector.
For example, the composite copper foil treated with the silane coupling agent according to the present invention can be bonded in layers with a resin substrate to produce a laminate, which can be used to manufacture a printed wiring board. The type of resin contained in the resin substrate is not particularly limited, but may be a thermoplastic resin or a thermosetting resin, and is preferably polyphenylene ether (PPE), epoxy, polyphenylene oxide (PPO), polybenzoxazole (PBO), polytetrafluoroethylene (PTFE), liquid crystal polymer (LCP), triphenylphossite (TPPI), fluororesin, polyetherimide, polyetheretherketone, polycycloolefin, bismaleimide resin, low dielectric constant polyimide, cyanate resin, or a mixture of these resins. The resin substrate may further contain an inorganic filler or glass fiber.
In addition, for example, when a negative electrode current collector is produced using a composite copper foil treated with the silane coupling agent according to the present invention, the adhesion between the copper foil and the negative electrode material is improved, and a good lithium ion battery with little capacity deterioration can be obtained. The negative electrode current collector for lithium ion batteries can be produced according to a known method. For example, a negative electrode material containing a carbon-based active material is prepared and dispersed in a solvent or water to form an active material slurry. This active material slurry is applied to a composite copper foil treated with the silane coupling agent according to the present invention, and then dried to evaporate the solvent and water. Thereafter, the composite copper foil is pressed and dried again, and then the negative electrode current collector is formed into a desired shape. The negative electrode material may contain silicon or a silicon compound, germanium, tin, lead, etc., which have a larger theoretical capacity than the carbon-based active material. In addition, not only an organic electrolyte solution in which a lithium salt is dissolved in an organic solvent as an electrolyte, but also a polymer made of polyethylene oxide or polyvinylidene fluoride may be used. The composite copper foil treated with the silane coupling agent according to the present invention can be applied not only to lithium ion batteries but also to lithium ion polymer batteries.

<1. Manufacturing of composite copper foil>
In Examples 1 to 27 and Comparative Examples 1 to 9, DR-WS (manufactured by Furukawa Electric Co., Ltd., thickness: 18 μm) was used as the copper foil. In Comparative Example 10, FV-WS (manufactured by Furukawa Electric Co., Ltd., thickness: 18 μm) that had already been roughened and plated on only one side was used. In Example 16, only the shiny side (the glossy side; the side that is flat compared to the opposite side) of DR-WS was subjected to oxidation treatment and electrolytic plating treatment.

(1) Pretreatment [Alkaline degreasing treatment]
The copper foil was immersed in a 40 g/L aqueous solution of sodium hydroxide at a liquid temperature of 50° C. for 1 minute, and then rinsed with water.
[Acid cleaning treatment]
The copper foil that had been subjected to the alkaline degreasing treatment was immersed in a 10% by weight aqueous sulfuric acid solution at a liquid temperature of 25° C. for 2 minutes, and then rinsed with water.
[Pre-dip processing]
The copper foil that had been subjected to the acid cleaning treatment was immersed for 1 minute in a pre-dip chemical solution containing 1.2 g/L of sodium hydroxide (NaOH) at a liquid temperature of 40°C.

(2) Oxidation Treatment The alkali-treated copper foil was immersed in an aqueous oxidation treatment solution shown in Table 1 under the prescribed conditions to perform an oxidation treatment on both sides in Examples 1 to 15, 17 to 27 and Comparative Examples 1 to 7 and 9. In Example 16, the copper foil was floated on the surface of the aqueous oxidation treatment solution shown in Table 1 to perform the oxidation treatment on only one side.
After these treatments, the copper foil was washed with water.

(3) Plating Treatment In Examples 1 to 15, 17 to 27 and Comparative Examples 1 to 9, nickel plating was performed on both sides using a nickel plating electrolyte (nickel sulfate 230 g/L; boric acid 25 g/L) under the conditions shown in Table 1. In Example 16, plating was performed on only one side under the conditions shown in Table 1 by placing an anode electrode only on the side to be plated.

(4) Coupling Treatment In Examples 1 to 4, 6 to 27 and Comparative Examples 3 to 9, the silane coupling agent solution shown in Table 1 was applied to one side, and after removing excess silane coupling agent with a bar coater, treatment was performed at 70° C. for 1 minute. In Example 5 and Comparative Examples 1 and 2, the sample was immersed in the silane coupling agent solution shown in Table 1, and then both sides were treated at 110° C. for 1 minute. Silane coupling agents (3-mercaptopropyltrimethoxysilane (KBE-903); 3-aminopropyltrimethoxysilane (KBM-903); 3-mercaptopropyltrimethoxysilane (KBM-803); 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (KBM-303); vinyltrimethoxysilane (KBM-1003); 3-methacryloxypropyltrimethoxysilane (KBM-502); 3-isocyanatopropyltriethoxysilane (KBE-9007N); 3-ureidopropyltrialkoxysilane (KBE-585); 3-acryloxypropyltrimethoxysilane (KBM-5103)) were purchased from Shin-Etsu Silicones.

For each of the examples and comparative examples, a plurality of test pieces were prepared under the same conditions. Since the comparative example 10 was a commercially available product, it was used as a test piece without being subjected to the treatments (1) to (4).
Cross-sectional images (magnification: 50,000 times) of Example 1 and Comparative Example 10 observed with a scanning electron microscope (SEM) are shown in Fig. 1. In Example 1, needle-like protrusions (arrows) of approximately the same thickness caused by acicular (crystal) copper oxide and coated with crystalline nickel could be confirmed, whereas bump-like protrusions (arrows) of different sizes caused by electrodeposition of copper particles could be confirmed in Comparative Example 10. Such needle-like protrusions cannot be observed if the nickel plating layer is too thick (for example, Comparative Example 5).

2. Calculation of Adhering Amount of Nickel and Silane Coupling Agent
The amount of nickel and the amount of silane coupling agent attached was determined by dissolving the copper foil in 12% nitric acid, measuring the Ni and Si concentrations in the obtained solution using an ICP emission spectrometer 5100 SVDV ICP-OES (manufactured by Agilent Technologies), and calculating the amount of Ni and the amount of Si per unit area of the copper foil used (the area in plan view of the copper foil in the case of single-sided treatment, and the area in plan view of the copper foil x 2 in the case of double-sided treatment).

<3. Measurement of BET specific surface area>
The BET specific surface area (actual total surface area per 1 g of copper foil) of each test piece was measured by a krypton gas adsorption BET multipoint method using a multi-sample high-performance specific surface area measurement device 3FLEX manufactured by Micromeritics Corp. Prior to the measurement, the test pieces were pretreated by drying under reduced pressure at 100° C. for 2 hours.
The test pieces used for the measurement were cut into 110 pieces of 30 mm x 7 mm per 3.83 g of original copper foil, and were introduced into the measurement device.
The results are shown in Table 2.

（２）第二の工程まで片面処置した銅箔（実施例１６）及び比較例１０の場合

結果を表２に示す。 4. Calculation of BET surface area ratio
The plan view area per gram of the original copper foil used and the BET specific surface area measured above were used to calculate the specific surface area according to the following formula.
(1) In the case of copper foil treated on both sides up to the second step (Examples 1 to 15, 17 to 27 and Comparative Examples 1 to 9)

(2) In the case of copper foil treated on one side up to the second step (Example 16) and Comparative Example 10

The results are shown in Table 2.

5. Calculation of Ra and Rz
The treated surface of the copper foil after the coupling agent treatment (when both sides were treated, the surface with the smaller roughness of the original foil) was measured using a confocal scanning electron microscope OPTELICS H1200 (manufactured by Lasertec Corporation), and Ra and Rz were calculated according to the method specified in JIS B 0601:2001 (based on the international standard ISO4287-1997). The measurement conditions were a scan width of 100 μm, a scan type of area, a light source of Blue, and a cutoff value of 1/5. The object lens was set to x100, the contact lens to x14, the digital zoom to x1, and the Z pitch to 10 nm, and data was obtained at three locations, and Ra and Rz were average values of the three locations.
The results are shown in Table 2.

<6. Measurement of peel strength>
Each resin substrate was heat-pressed to the treated surface of each test piece (in the case of double-sided treatment, the surface of the original foil with the smaller roughness) under the following conditions.
In the case of MEGTRON7 (manufactured by Panasonic, thickness 100 μm), the material was pressed at 0.49 MPa while being heated to 110° C. using a vacuum press, and then thermocompression bonded by holding at 210° C. and 2.94 MPa for 120 minutes.
In the case of Vecstar CT-Z film (LCP) (Kuraray Co., Ltd., thickness 50 μm), it was heated at 0 MPa using a vacuum press until it reached 260° C., held for 15 minutes after reaching 260° C., and then pressed at 4 MPa while heating until it reached 300° C. It was then held at 300° C. for 10 minutes for thermocompression bonding.
In the case of PIXEO FRS (PI) (manufactured by Kaneka Corporation, thickness 12.5 μm), thermocompression bonding was performed by holding the material at 350° C. and 5 MPa for 20 minutes using a vacuum press.
The circuit wiring board was prepared by masking with a 10 mm wide tape and etching. Thereafter, the copper foil was peeled from the resin in a 90° direction at a speed of 50 mm/min, and the peel strength was measured.

The evaluation criteria for peel strength are:
When MEGTRON7 was used,
◎: 0.6 kgf/cm or more ○: 0.5 to 0.6 kgf/cm
△:0.4~0.5kgf/cm
×: Less than 0.4 kgf/cm;
When using Vecstar CT-Z film (LCP),
◎: 0.5 kgf/cm or more ○: 0.4 to 0.5 kgf/cm
△:0.3~0.4kgf/cm
×: Less than 0.3 kgf/cm;
When using PIXEO FRS (PI),
◎: 0.6 kgf/cm or more ○: 0.5 to 0.6 kgf/cm
△:0.4~0.5kgf/cm
×: Less than 0.4 kgf/cm
The results are shown in Table 2. All of the examples showed good peel strength.

8. Measurement of high frequency characteristics
Each test piece was thermocompression bonded to a 100 μm thick MEGTRON7 to prepare a microstrip line with a length of 200 mm. The circuit width was 230 μm and the characteristic impedance was 50 Ω. A high-frequency signal up to 40 GHz was transmitted through this transmission line using a network analyzer to measure the transmission loss.
The evaluation criteria for transmission loss at 40 GHz were: ⊚: -9.5 dB or more; ◯: less than -9.5 dB to -10 dB or more; and x: less than -10 dB.
The results are shown in Table 2. All of the examples showed good results.

8. Measurement of Etching Properties
The copper-clad laminates prepared by thermocompression bonding each test piece to MEGTRON7 were cut into 10 cm x 10 cm size, and copper foil patterns were formed by etching. Thereafter, based on 2.5.17 of the IPC test standard TM-650, a resistance meter with a maximum range of 10 ¹⁴ Ω was used to measure the resistance on the resin substrate, and the etching property was confirmed by whether it was equal to or greater than the maximum range (◎) or not (×). When metal residue remains on the surface of the resin substrate during etching, electrical continuity can be obtained. When it is equal to or greater than the maximum range, electrical continuity cannot be obtained, and etching is good.
The results are shown in Table 2. All of the examples showed good results.

In the third step, a silane coupling agent layer is formed. In the cases of Comparative Examples 1, 2, and 4 where the amount of silane coupling agent attached is small or absent, sufficient silane coupling agent is not attached to obtain adhesion, and adhesion cannot be ensured. In addition, in the case of Comparative Example 3 where the amount of silane coupling agent attached is excessive, adhesion cannot be ensured due to destruction of the silane coupling agent layer. In contrast, in the examples where an appropriate amount of silane coupling agent is attached, good adhesion was shown to all resin substrates.
In the second step, a nickel layer is formed. In Comparative Examples 5 and 6, excessive nickel was applied, and the fine uneven shape formed in the first step was buried, so that the anchor effect was not obtained and adhesion could not be ensured. The high frequency characteristics were also inferior to the Examples due to the influence of the magnetic permeability caused by the application of excessive nickel. In terms of etching properties, Comparative Example 6 was also not completely etched due to the application of excessive nickel, and nickel remained on the resin surface. In Comparative Example 9, the amount of nickel attached was insufficient, so the effect as a protective layer was not sufficiently obtained and adhesion could not be ensured. In contrast, the Examples in which an appropriate amount of nickel was attached showed good characteristics.
In the first step, a copper oxide layer having a fine uneven shape is formed by oxidation treatment. In Comparative Example 7, an excessive uneven shape was formed in the first step, so that a sufficient protective layer could not be formed by nickel in the subsequent second step, and adhesion was not obtained. In addition, the roughness became too large, which adversely affected the high frequency characteristics and etching characteristics. In Comparative Example 8, the first step was not performed, so that a fine uneven shape was not formed, the anchor effect was low, and sufficient adhesion could not be ensured. In contrast, the examples having an appropriate fine uneven shape showed good characteristics.

As described above, the present invention is characterized by a low roughness and a large surface area, resulting in a large amount of silane coupling agent attached per unit area. This makes it possible to obtain superior high-frequency characteristics and adhesion compared to copper foils with conventional roughening particles such as those in Comparative Example 10.

The present invention makes it possible to provide a novel composite copper member, a laminate and an electronic component using the same, a composite copper foil for high-frequency transmission, and a laminate for high-frequency transmission and an electronic component for high-frequency transmission using the same.

Claims (27)

A composite copper member having a layer containing needle-shaped copper oxide on at least a part of the surface of a copper member, a nickel layer on the layer containing copper oxide, and a silane coupling agent layer on the surface on which the nickel layer is formed, wherein the adhesion amount of the silane coupling agent layer is 7 μg/ ^dm2 or more and 900 μg/dm2 or ^less (Si converted weight per unit area of the copper member) ,
the Rz (calculated by the method defined in JIS B 0601:2001 (based on international standard ISO 4287-1997)) of the surface on which the silane coupling agent layer is formed is 0.2 μm or more and 1.5 μm or less;
A composite copper member , wherein the thickness of the nickel layer is 0.5 mg/dm2 or ^more and 10.0 mg/dm2 ^or less (nickel weight per unit area of the copper member). A composite copper member having a layer containing needle-shaped copper oxide on at least a part of the surface of a copper member, a nickel layer on the layer containing copper oxide, and a silane coupling agent layer on the surface on which the nickel layer is formed, wherein the amount of adhesion of the silane coupling agent layer is 7 μg/dm ² More than 900 μg/dm ² The weight per unit area of the copper member is calculated as the weight converted into silicon.
the BET surface area ratio of the surface on which the silane coupling agent layer is formed (surface area of the surface on which the silane coupling agent layer is formed/planar view area of the copper member on which the silane coupling agent layer is formed, calculated by the BET method) is 3 or more and 20 or less;
The thickness of the nickel layer is 0.5 mg/dm ² More than 10.0 mg/dm ² A composite copper member having a nickel weight per unit area of the copper member of: A composite copper member having a layer containing needle-shaped copper oxide on at least a part of the surface of a copper member, a nickel layer on the layer containing copper oxide, and a silane coupling agent layer on the surface on which the nickel layer is formed, wherein the amount of adhesion of the silane coupling agent layer is 7 μg/dm ² More than 900 μg/dm ² The weight per unit area of the copper member is calculated as the weight converted into silicon.
A composite copper member having a peel strength of 0.4 kgf/cm or more when a resin substrate is thermocompression-bonded to a silane coupling agent layer of the composite copper member under specific conditions and then the composite copper member is peeled from the resin substrate in a 90° direction at a speed of 50 mm/min. The BET surface area ratio of the surface on which the silane coupling agent layer is formed (surface area of the surface on which the silane coupling agent layer is formed / plan view area of the copper member on which the silane coupling agent layer is formed, calculated by the BET method) is 3 or more and 20 or less. The composite copper member according to claim 1 or 3 . The composite copper member according to claim 3 or 4 , wherein the nickel layer has a thickness of 0.5 mg/dm2 ^{or more and} 25 mg/dm2 or ^less (nickel weight per unit area of the copper member). The Ra (calculated by a method defined in JIS B 0601:2001 (based on international standard ISO 4287-1997)) of the surface on which the silane coupling agent layer is formed is 0.02 μm or more and 0.17 μm or less. The composite copper member according to any one of claims 1 to 5 . The Rz (calculated by a method defined in JIS B 0601:2001 (based on international standard ISO 4287-1997)) of the surface on which the silane coupling agent layer is formed is 0.2 μm or more and 1.5 μm or less. The composite copper member according to any one of claims 2 to 6 . The surface on which the silane coupling agent layer is formed has a BET surface area ratio / Rz (calculated by a method defined in JIS B 0601:2001 (based on international standard ISO 4287-1997)) of 4 μm ^-1 or more. The composite copper member according to any one of claims 1 to 7 . The silane coupling agent is represented by the following formula:
Y-Si(OR) ₃
(Y is selected from the group consisting of vinyl, epoxy, amino, methacryl, mercapto, 3-mercaptopropyl, 3-aminopropyl, 3-mercaptopropyl, 2-(3,4-epoxycyclohexyl)ethyl, 3-methacryloxypropyl, 3-isocyanatopropyl, 3-ureidopropyl, and 3-acryloxypropyl groups;
The composite copper member according to any one of claims 1 to 8 , comprising a compound represented by the formula (I) (wherein -OR is an alkoxy group). A laminate in which a resin substrate is laminated on the silane coupling agent layer of the composite copper member according to any one of claims 1 to 9 . A printed wiring board comprising the laminate of claim 10 . The composite copper member according to any one of claims 1 to 9 , wherein the copper member is a copper foil. A negative electrode current collector comprising the composite copper member of claim 12 . A method for producing a composite copper component treated with a silane coupling agent, comprising:
a first step of forming a needle-like copper oxide layer having an average thickness of 400 nm or less on at least a part of a surface of a copper member by oxidation treatment;
A second step of forming a nickel layer having a thickness of 0.5 mg/dm2 ^{or more} and 10.0 mg/dm2 or ^less (nickel weight per unit area of the copper member) on the copper oxide layer by electrolytic plating;
A third step of coating the surface on which the nickel layer is formed with a silane coupling agent in an amount of 7 μg/dm ² or more and 900 μg/dm ² or less (weight in terms of Si per unit area of the copper member),
Manufacturing method. A method for producing a composite copper component treated with a silane coupling agent, comprising:
a first step of forming a needle-like copper oxide layer having an average thickness of 400 nm or less on at least a part of a surface of a copper member by oxidation treatment;
a second step of forming a nickel layer on the copper oxide layer by electrolytic plating;
The surface on which the nickel layer is formed is coated with 7 μg/dm ² More than 900 μg/dm ² A third step of coating the copper member with a silane coupling agent in an amount of the following (weight in terms of Si per unit area of the copper member):
A resin substrate is thermocompressed under specific conditions to a surface of the composite copper member treated with a silane coupling agent, and then the composite copper member is peeled from the resin substrate in a 90° direction at a speed of 50 mm/min. The peel strength is 0.4 kgf/cm or more.
Manufacturing method. The method according to claim 14 or 15, wherein the surface on which the copper oxide layer is formed after the first step has an Ra (calculated by a method specified in JIS B 0601:2001 (in accordance with international standard ISO 4287-1997)) of 0.035 or more and 0.15 or less . The method according to any one of claims 14 to 16, wherein Rz (calculated by a method defined in JIS B 0601:2001 (based on international standard ISO 4287-1997)) of the surface on which the copper oxide layer is formed after the first step is 0.25 or more and 1.450 or less . The method according to any one of claims 14 to 17, characterized in that the current density of the electrolytic plating treatment in the second step is 5 A/dm2 or ^less . The manufacturing method according to any one of claims 15 to 18 , wherein the thickness of the nickel layer is 0.5 mg/dm2 or ^more and 25 mg/dm2 or ^less (nickel weight per unit area of the copper member). The silane coupling agent is represented by the following formula:
X-Si(OR) ₃
(X is selected from the group consisting of vinyl, epoxy, amino, methacryl, mercapto, 3-mercaptopropyl, 3-aminopropyl, 3-mercaptopropyl, 2-(3,4-epoxycyclohexyl)ethyl, vinyl, 3-methacryloxypropyl, 3-isocyanatopropyl, 3-ureidopropyl, and 3-acryloxypropyl groups;
The method according to any one of claims 14 to 19 , comprising a compound represented by the formula (I) (-OR is an alkoxy group). The method according to any one of claims 14 to 20, wherein the Ra (calculated according to the method specified in JIS B 0601:2001 (based on international standard ISO4287-1997)) of the surface coated with the silane coupling agent after the third step is 0.02 μm or more and 0.17 μm or less. The method according to any one of claims 14 to 21, wherein the Rz (calculated by the method specified in JIS B 0601:2001 (based on international standard ISO4287-1997)) of the surface coated with the silane coupling agent after the third step is 0.2 μm or more and 1.5 μm or less. The method according to any one of claims 14 to 22 , wherein the BET surface area ratio of the surface coated with the silane coupling agent after the third step is 3 or more and 20 or less. The method according to any one of claims 14 to 23, wherein the value of the BET surface area ratio/Rz (calculated by the method specified in JIS B 0601:2001 (based on international standard ISO 4287-1997)) of the surface coated with the silane coupling agent after the third step is 4 μm ^-1 or more. A method for producing a laminate, comprising a step of thermocompression bonding a resin substrate to a copper member treated with a silane coupling agent produced by the method for producing a laminate according to any one of claims 14 to 24 . The method according to any one of claims 14 to 24 , wherein the copper member is a copper foil. A method for producing a secondary battery, comprising a step of coating and supporting a conductive active material on a composite copper member treated with a silane coupling agent produced by the method for producing a secondary battery according to claim 26 .