Surface-treated copper foil, copper-clad laminates and printed wiring boards

Abstract

Provided is a surface-treated copper foil comprising a copper foil and a surface-treated layer formed on at least one surface of the copper foil. The actual volume Vmc of a core portion of the surface-treated layer is 0.35 to 0.55 μｍ3 / μｍ2.

Description

[Technical Field]

[0001] The present disclosure relates to a surface-treated copper foil, a copper-clad laminate, and a printed wiring board. [Background technology]

[0002] Copper-clad laminates are widely used in various applications, such as flexible printed wiring boards. Flexible printed wiring boards are manufactured by etching the copper foil of a copper-clad laminate to form a conductor pattern (also called a "wiring pattern"), and then mounting electronic components on the conductor pattern by connecting them with solder.

[0003] In recent years, electronic devices such as personal computers and mobile terminals have become faster and larger in communication speed and capacity, leading to an increase in the frequency of electrical signals, and flexible printed wiring boards that can accommodate this are in demand. In particular, the higher the frequency of the electrical signal, the greater the loss (attenuation) of signal power, making it more difficult to read data. For this reason, there is a demand for reducing signal power loss.

[0004] The causes of signal power loss (transmission loss) in electronic circuits can be broadly divided into two categories: 1) conductor loss, i.e., loss due to copper foil, and 2) dielectric loss, i.e., loss due to the resin substrate. In the high frequency range, current has the property of flowing on the surface of a conductor (i.e., the skin effect). Therefore, if the copper foil surface is rough, the current will flow along a complex path. Therefore, in order to reduce the conductor loss of high frequency signals, it is desirable to reduce the surface roughness of the copper foil. Hereinafter, when the terms "transmission loss" and "conductor loss" are simply used in this specification, they mainly mean "transmission loss of high frequency signals" and "conductor loss of high frequency signals."

[0005] Dielectric loss depends on the type of resin substrate. For this reason, it is desirable to use a resin substrate made of a low-dielectric material (e.g., liquid crystal polymer, low-dielectric polyimide) for circuit boards through which high-frequency signals flow. Dielectric loss is also affected by the adhesive used to bond the copper foil to the resin substrate. For this reason, it is desirable to bond the copper foil to the resin substrate without using an adhesive. Therefore, in order to bond the copper foil and the resin substrate without adhesive, it has been proposed to form a surface treatment layer on at least one side of the copper foil.For example, Patent Document 1 proposes a method in which a roughening treatment layer made of roughening particles is provided on the copper foil, and a silane coupling treatment layer is formed on the outermost surface layer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-112009 Summary of the Invention [Problem to be solved by the invention]

[0007] When the copper foil surface is roughened, the anchoring effect of the roughening particles can improve adhesion between the copper foil and the resin substrate, but the skin effect can also increase conductor loss. For this reason, it is desirable to reduce the amount of roughening particles electrodeposited on the copper foil surface. On the other hand, reducing the amount of roughening particles electrodeposited on the copper foil surface reduces the anchoring effect of the roughening particles. As a result, sufficient adhesion between the copper foil and the resin substrate cannot be achieved. In particular, resin substrates made of low-dielectric materials such as liquid crystal polymers and low-dielectric polyimides are more difficult to bond to copper foil than conventional resin substrates. Therefore, there is a need to develop a method to improve adhesion between copper foil and the resin substrate. Furthermore, although the silane coupling treatment layer has the effect of improving the adhesion between the copper foil and the resin substrate, depending on the type of the silane coupling treatment layer, the effect of improving the adhesion may not be sufficient.

[0008] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a surface-treated copper foil capable of improving adhesion to a resin substrate, particularly a resin substrate suitable for high-frequency applications. Another object of the present invention is to provide a copper-clad laminate having excellent adhesion between a resin substrate, particularly a resin substrate suitable for high-frequency applications, and a surface-treated copper foil. Furthermore, in another aspect, an object of the present invention is to provide a printed wiring board having excellent adhesion between a resin substrate, particularly a resin substrate suitable for high frequency applications, and a circuit pattern. [Means for solving the problem]

[0009] The present inventors have conducted extensive research into surface-treated copper foils in order to solve the above-mentioned problems. As a result, based on the finding that the volume Vmc of the solid portion of the core portion of the surface treatment layer is related to the surface shape of the surface treatment layer (particularly, the size of the roughening particles in the roughening treatment layer), they have found that by controlling the volume Vmc of the solid portion of the core portion of the surface treatment layer within a predetermined range, the anchoring effect of the surface treatment layer can be enhanced and the adhesion between the surface-treated copper foil and the resin substrate can be improved.

[0010] That is, in one aspect, an embodiment of the present invention comprises a copper foil and a surface treatment layer formed on at least one surface of the copper foil, and a substantial part volume Vmc of a core part of the surface treatment layer is 0.35 to 0.55 μm 3 / μm 2 Yes and the level difference Sk of the core portion of the surface treatment layer is 0.70 to 1.50 μm. This relates to surface-treated copper foil. In another aspect, the present invention provides a copper foil having a surface treatment layer formed on at least one surface of the copper foil, wherein the substantial volume Vmc of a core portion of the surface treatment layer is 0.35 to 0.55 μm 3 / μm 2 and the skewness Ssk of the surface treatment layer is 0.10 to 1.00. Furthermore, in another aspect, an embodiment of the present invention is a copper foil having a surface treatment layer formed on at least one surface of the copper foil, wherein the substantial volume Vmc of a core portion of the surface treatment layer is 0.35 to 0.55 μm 3 / μm 2 and the Zn coating weight in the surface treatment layer is 6 to 200 μm / dm 2 The present invention relates to a surface-treated copper foil.

[0011] In another aspect, an embodiment of the present invention relates to a copper-clad laminate comprising the surface-treated copper foil and a resin substrate adhered to the surface treatment layer of the surface-treated copper foil. Furthermore, in another aspect, an embodiment of the present invention relates to a printed wiring board having a circuit pattern formed by etching the surface-treated copper foil of the copper-clad laminate. [Effects of the Invention]

[0012] According to one aspect of the present invention, a surface-treated copper foil capable of improving adhesion to a resin substrate, particularly a resin substrate suitable for high-frequency applications, can be provided. In another aspect, an embodiment of the present invention can provide a copper-clad laminate having excellent adhesion between a resin substrate, particularly a resin substrate suitable for high-frequency applications, and a surface-treated copper foil. Furthermore, according to another aspect of the present invention, a printed wiring board can be provided that has excellent adhesion between a resin substrate, particularly a resin substrate suitable for high frequency applications, and a circuit pattern. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a graph showing a typical load curve of a surface treatment layer. [Figure 2] 1 is a cross-sectional view schematically showing a surface-treated copper foil having a roughened layer on one side thereof, which is an example of an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Preferred embodiments of the present invention will be described in detail below, but the present invention should not be construed as being limited thereto, and various modifications and improvements can be made based on the knowledge of those skilled in the art without departing from the gist of the present invention. The multiple components disclosed in the following embodiments can be appropriately combined to form various inventions. For example, some components may be deleted from all the components shown in the following embodiments, or components from different embodiments may be appropriately combined.

[0015] The surface-treated copper foil according to an embodiment of the present invention comprises a copper foil and a surface treatment layer formed on at least one surface of the copper foil, and the core volume Vmc of the surface treatment layer is 0.35 to 0.55 μm 3 / μm 2 is. According to the above-mentioned constitution, it is possible to realize a surface-treated copper foil capable of improving adhesion to a resin substrate, particularly a resin substrate suitable for high frequency applications.

[0016] The surface treatment layer may be formed on only one side of the copper foil, or may be formed on both sides of the copper foil. When the surface treatment layer is formed on both sides of the copper foil, the type of the surface treatment layer may be the same or different. When the types of the surface treatment layers formed on both sides of the copper foil are different, for example, a surface treatment layer including a roughening layer is formed on one side of the copper foil, and a surface treatment layer not including a roughening layer is formed on the other side of the copper foil.

[0017] The surface profile of the surface treatment layer can be determined using surface texture parameters, which are obtained in accordance with ISO 25178-2:2012 by measuring the surface profile and analyzing the load curve calculated from the measurement data. Before explaining the load curve, the load area ratio will be explained. The area coverage ratio is a ratio obtained by dividing the area corresponding to the cross section of a three-dimensional object to be measured when the object is cut at a plane of a certain height by the area of ​​the measurement field. In this disclosure, the object to be measured is assumed to be a copper foil or a surface treatment layer of a surface-treated copper foil. The load curve is a curve that shows the areal load ratio at each height. The height near an areal load ratio of 0% represents the height of the highest part of the object being measured. The height near an areal load ratio of 100% represents the height of the lowest part of the object being measured.

[0018] FIG. 1 is a graph showing a typical load curve of a surface treatment layer. The load curve can be used to express the volume of the solid part and the volume of the void part of the surface treatment layer. The volume of the solid part corresponds to the volume of the part occupied by the solid part of the object to be measured in the measurement field of view. The volume of the void part corresponds to the volume occupied by the space between the solid parts in the measurement field of view. The load curve described in the present disclosure is divided into a valley portion, a core portion, and a peak portion, with the areal load ratios of 10% and 80% as boundaries. 1, the following describes each parameter in relation to the surface treatment layer according to the embodiment of the present invention. Vvv denotes the volume of the voids in the valleys of the surface treatment layer, Vvc denotes the volume of the voids in the core of the surface treatment layer, Vmp denotes the volume of the solid part of the peaks of the surface treatment layer, and Vmc denotes the volume of the solid part of the core of the surface treatment layer. Sk denotes the level difference of the core of the surface treatment layer (the difference between the upper and lower limit levels of the core), Spk denotes the average height of the peaks of the surface treatment layer, and Svk denotes the average depth of the valleys of the surface treatment layer. The peaks are the high parts of the object to be measured, the valleys are the low parts of the object to be measured, and the core is the part of the object to be measured other than the peaks and valleys, i.e., the part with a height close to the average.

[0019] The substantial volume Vmc of the core portion of the surface treatment layer (hereinafter sometimes simply referred to as "Vmc") is related to the surface shape of the surface treatment layer. In particular, when the surface treatment layer includes a roughening treatment layer, it is related to the size of the roughening particles that make up the roughening treatment layer. As described above, in the surface-treated copper foil according to the embodiment of the present invention, the Vmc of the surface treatment layer is 0.35 to 0.55 μm. 3 / μm 2 In particular, when the surface treatment layer includes a roughened treatment layer, if the Vmc is in this range, the size (height and width) of the roughened particles will be in an appropriate range, and the roughened particles will be less likely to break when the surface treatment layer is bonded to the resin substrate, improving the anchor effect. When the Vmc of the surface treatment layer is 0.35 μm, 3 / μm 2 When Vmc of the surface treatment layer is 0.55 μm or more, a desired anchor effect can be obtained. 3 / μm 2 If it is less than this, the transmission loss can be reduced. The Vmc of the surface treatment layer is set to 0.37 to 0.52 μm from the viewpoint of stably enhancing the anchor effect of the surface treatment layer. 3 / μm 2 is preferable, and 0.38 to 0.45 μm 3 / μm 2 is more preferred.

[0020] The level difference Sk of the core portion of the surface treatment layer (hereinafter sometimes simply referred to as "Sk") is related to the ease with which the core portion (portion of average height) of the surface treatment layer penetrates into the resin substrate when the surface treatment layer is bonded to the resin substrate. In particular, when the surface treatment layer includes a roughening treatment layer, the level difference Sk is related to the ease with which the portion of the roughening particles constituting the roughening treatment layer with an average height penetrates into the resin substrate. When the Vmp of the surface treatment layer is within the above range, the Sk of the surface treatment layer may be 0.70 to 1.50 μm from the viewpoint of ensuring that the core portion of the surface treatment layer penetrates into the resin substrate. With an Sk within this range, the anchoring effect due to the penetration of the core portion of the surface treatment layer into the resin substrate can be enhanced, thereby improving the adhesion between the surface-treated copper foil and the resin substrate. When the Sk of the surface treatment layer is 0.70 μm or more, the core portion of the surface treatment layer easily penetrates into the resin substrate, thereby achieving the desired anchoring effect. When the Sk of the surface treatment layer is 1.50 μm or less, for example, the roughening particles are less likely to break, thereby achieving the desired anchoring effect. From the viewpoint of stably ensuring that the surface treatment layer bites into the resin substrate at the core portion, the Sk of the surface treatment layer is more preferably 0.85 to 1.30 μm, and even more preferably 1.03 to 1.18 μm.

[0021] The surface of copper foil on which a surface treatment layer is formed generally has minute irregularities. For example, in the case of rolled copper foil, oil pits formed by rolling oil during rolling form minute recesses on the surface. In addition, in the case of electrolytic copper foil, polishing streaks formed by the rotating drum during polishing cause minute irregularities on the rotating drum side surface of the electrolytic copper foil deposited on the rotating drum. If minute irregularities exist on the copper foil, for example, when forming a roughening treatment layer, current concentrates around the protrusions, causing excessive growth of roughening particles, while current is insufficient around the recesses, making it difficult for the roughening particles to grow. As a result, coarse roughening particles are formed around the protrusions of the copper foil, while roughening particles are too small or not formed around the recesses of the copper foil, i.e., the roughening particles are not uniformly formed on the copper foil surface. In a surface-treated copper foil containing a large number of coarse roughening particles, when a force is applied to peel the surface-treated copper foil after bonding to a resin substrate, stress is concentrated on the coarse roughening particles, making the foil more likely to break, which can result in a decrease in adhesive strength to the resin substrate. Furthermore, in a surface-treated copper foil containing insufficient roughening particles, the anchoring effect of the roughening particles is reduced, and sufficient adhesion between the copper foil and the resin substrate can be insufficient.

[0022] From the above viewpoint, the skewness Ssk of the surface treatment layer (hereinafter sometimes simply abbreviated as "Ssk") may be 0.10 to 1.00. Here, Ssk is a parameter that represents the degree of bias (skewness) of a height histogram created based on the average height. For example, Ssk = 0.00 means that the height distribution is symmetrical with respect to the average line. Furthermore, when Ssk > 0.00, the larger the value, the more the height distribution is biased downward relative to the average line. Conversely, when Ssk < 0.00, the smaller the value, the more the height distribution is biased upward relative to the average line. Therefore, Ssk of the surface treatment layer is an index for evaluating the height distribution of the unevenness of the surface treatment layer. The Ssk of the surface treatment layer being 0.10 to 1.00 means, for example, that when the surface treatment layer includes a roughening particle layer, there are few areas where roughening particles (i.e., large roughening particles) have grown over on the convex portions of the copper foil surface, and there are few areas where roughening particles have not formed around concave portions such as oil pits on the copper foil surface. From the viewpoint of stably ensuring the above effects, the Ssk of the surface treatment layer is more preferably 0.30 to 0.90, and even more preferably 0.45 to 0.80. The Ssk of the surface treatment layer can be determined in accordance with ISO 25178-2:2012 by measuring the surface roughness and analyzing the profile curve calculated from the measurement data.

[0023] The amount of Zn attached in the surface treatment layer is not particularly limited, but is preferably 6 to 200 μm / dm 2 By controlling the Zn coating weight within this range, the solder heat resistance of the circuit pattern formed from the surface-treated copper foil can be improved. From the viewpoint of stably improving this effect, the Zn coating weight in the surface treatment layer is preferably 82 to 200 μm / dm 2 It is more preferable that: The Zn adhesion amount in the surface treatment layer can be measured by dissolving the surface treatment layer in 20% by mass nitric acid and performing quantitative analysis by atomic absorption spectrometry using an atomic absorption spectrophotometer (AA240FS, manufactured by VARIAN). When surface treatment layers are provided on both sides of the copper foil, the surface of the surface treatment layer that is not to be measured is protected, and then the surface treatment layer to be measured is dissolved and quantitatively analyzed.

[0024] The type of surface treatment layer is not particularly limited as long as it has the above-mentioned surface shape, and various surface treatment layers known in the art can be used. Examples of the surface treatment layer include a roughening treatment layer, a chemical-resistant treatment layer, a heat-resistant treatment layer, a chromate treatment layer, and a silane coupling treatment layer. These layers can be used alone or in combination of two or more. Among these, it is preferable that the surface treatment layer contains a roughening treatment layer from the viewpoint of adhesion to the resin substrate. When the surface treatment layer contains one or more layers selected from the group consisting of a chemical-resistant treatment layer, a heat-resistant treatment layer, a chromate treatment layer, and a silane coupling treatment layer, it is preferable that these layers are provided on the roughening treatment layer.

[0025] The roughening treatment layer contains roughening particles. The roughening particles may include primary roughening particles and secondary roughening particles. The secondary roughening particles may have a different chemical composition from the primary roughening particles. It is preferable that a cover plating layer be formed on at least a portion of the surface of the primary roughening particles. FIG. 2 is a cross-sectional view schematically showing a surface-treated copper foil having a roughened layer on one side of the copper foil. As shown in Figure 2, one example of an embodiment of the present invention includes a roughened layer formed on one surface of a copper foil (10). The roughened layer includes primary roughened particles (20), a cover plating layer (30) covering the primary roughened particles (20), and secondary roughened particles (40) formed on the cover plating layer (30). It is preferable that the primary roughened particles (20) covered with the cover plating layer (30) are substantially spherical, and the secondary roughened particles (40) are formed so as to spread out in a dendritic pattern. A surface-treated copper foil in which Vmc, Sk, and Ssk are controlled within the above ranges is believed to have such a cross-sectional structure.

[0026] The roughening particles may be formed from, but are not limited to, a single element selected from the group consisting of copper, nickel, cobalt, phosphorus, tungsten, arsenic, molybdenum, chromium, and zinc, or an alloy containing two or more of these elements. The primary roughening particles are preferably formed from copper or a copper alloy, especially copper. The secondary roughening particles are preferably formed from an alloy containing copper, cobalt and nickel. The cover plating layer is not particularly limited, but can be formed from copper, silver, gold, nickel, cobalt, zinc, etc. Among these, it is preferable that the cover plating layer be formed from copper.

[0027] The roughened layer can be formed, for example, by performing a primary roughening treatment to form primary roughening particles, followed by cover plating to form a cover plating layer, and then a secondary roughening treatment to form secondary roughening particles. By performing the roughening treatment in this manner, it becomes easier to form a surface treatment layer having the above-described surface shape. Each particle and layer can be formed by electroplating. Specifically, the primary roughening particles can be formed by electroplating using a plating solution containing a trace amount of a tungsten compound. The cover plating layer and secondary roughening particles can be formed by electroplating using a plating solution containing specific components.

[0028] The tungsten compound is not particularly limited, but for example, sodium tungstate (Na2WO4) can be used. The content of the tungsten compound in the plating solution is preferably 1 ppm or more. The surface of the copper foil on which the roughened layer is formed has minute depressions such as oil pits, and the roughening particles may be too small or not formed around the depressions. However, such a content prevents overgrowth of the primary roughening particles formed on the relatively smooth portions of the copper foil and facilitates the formation of primary roughening particles around the depressions. The upper limit of the tungsten compound content is not particularly limited, but is preferably 20 ppm from the viewpoint of preventing an increase in electrical resistance.

[0029] The electroplating conditions for forming the roughened layer are not particularly limited and may be adjusted depending on the electroplating apparatus used, but typical conditions are as follows: Note that each electroplating step may be performed once or multiple times. (Conditions for forming primary roughening particles) Plating solution composition: 5-15g / L Cu, 40-100g / L sulfuric acid, 1-6ppm sodium tungstate Plating solution temperature: 20~50℃ Electroplating conditions: current density 30~90A / dm 2 , time 0.1 to 8 seconds

[0030] (Conditions for forming the cover plating layer) Plating solution composition: 10-30g / L Cu, 70-130g / L sulfuric acid Plating solution temperature: 30 to 60°C Electroplating conditions: current density 4.8~15A / dm 2 , time 0.1 to 8 seconds

[0031] (Conditions for forming secondary roughening particles) Plating solution composition: 10-20g / L Cu, 5-15g / L Co, 5-15g / L Ni Plating solution temperature: 30~50℃ Electroplating conditions: current density 24~50A / dm 2 , time 0.3~0.8 seconds

[0032] The chemical-resistant treatment layer and the heat-resistant treatment layer are not particularly limited and can be formed from materials known in the technical field. Note that, since the chemical-resistant treatment layer may also function as a heat-resistant treatment layer, a single layer having the functions of both the chemical-resistant treatment layer and the heat-resistant treatment layer may be formed as the chemical-resistant treatment layer and the heat-resistant treatment layer. The chemical-resistant layer and / or heat-resistant layer may be a layer containing one or more elements (which may be in any form, such as metal, alloy, oxide, nitride, or sulfide) selected from the group consisting of nickel, zinc, tin, cobalt, molybdenum, copper, tungsten, phosphorus, arsenic, chromium, vanadium, titanium, aluminum, gold, silver, platinum group elements, iron, and tantalum. Among these, the chemical-resistant layer is preferably a Co-Ni layer. The heat-resistant layer is preferably a Ni-Zn layer.

[0033] The chemical-resistant layer and the heat-resistant layer can be formed by electroplating. The conditions are not particularly limited and can be adjusted depending on the electroplating equipment used. However, the conditions for forming the chemical-resistant layer (Co-Ni layer) and the heat-resistant layer (Ni-Zn layer) using a general electroplating equipment are as follows. Note that the electroplating may be performed once or multiple times.

[0034] (Chemical-resistant layer: Co-Ni layer formation conditions) Plating solution composition: 1-8g / L Co, 5-20g / L Ni Plating solution pH: 2 to 3 Plating solution temperature: 40~60℃ Electroplating conditions: current density 1~20A / dm 2 , time 0.3~0.6 seconds

[0035] (Heat-resistant layer: Ni-Zn layer formation conditions) Plating solution composition: 1 to 30 g / L Ni, 1 to 30 g / L Zn Plating solution pH: 2 to 5 Plating solution temperature: 30~50℃ Electroplating conditions: current density 0.1~10A / dm 2 , time 0.1 to 5 seconds

[0036] The chromate treatment layer is not particularly limited, and can be formed from materials known in the art. Here, in this specification, the term "chromate-treated layer" refers to a layer formed with a solution containing chromic anhydride, chromic acid, dichromate, or dichromate. The chromate-treated layer may be a layer containing one or more elements (which may be in any form, such as metal, alloy, oxide, nitride, or sulfide) selected from the group consisting of cobalt, iron, nickel, molybdenum, zinc, tantalum, copper, aluminum, phosphorus, tungsten, tin, arsenic, and titanium. Examples of chromate-treated layers include chromate-treated layers treated with an aqueous solution of chromic anhydride or potassium dichromate, and chromate-treated layers treated with a treatment solution containing chromic anhydride or potassium dichromate and zinc.

[0037] The chromate treatment layer can be formed by a known method such as immersion chromate treatment or electrolytic chromate treatment. The conditions are not particularly limited, but for example, the conditions for forming a general chromate treatment layer are as follows. The chromate treatment may be performed once or multiple times. Chromate solution composition: 1-10g / L K2Cr2O7, 0.01-10g / L Zn Chromate solution pH: 2 to 5 Chromate solution temperature: 30~55℃ Electrolysis conditions: current density 0.1~10A / dm 2 , time 0.1 to 5 seconds (for electrolytic chromate treatment)

[0038] The silane coupling treatment layer is not particularly limited, and can be formed from a material known in the art. In this specification, the term "silane coupling treatment layer" means a layer formed with a silane coupling agent. The silane coupling agent is not particularly limited, and those known in the art can be used. Examples of silane coupling agents include amino-based silane coupling agents, epoxy-based silane coupling agents, mercapto-based silane coupling agents, methacryloxy-based silane coupling agents, vinyl-based silane coupling agents, imidazole-based silane coupling agents, and triazine-based silane coupling agents. Among these, amino-based silane coupling agents and epoxy-based silane coupling agents are preferred. The above silane coupling agents can be used alone or in combination of two or more. A typical method for forming the silane coupling treatment layer is to apply a 1 to 3% by volume aqueous solution of the above-mentioned silane coupling agent and dry it to form the silane coupling treatment layer.

[0039] The copper foil is not particularly limited, and may be either an electrolytic copper foil or a rolled copper foil. Electrodeposited copper foil is generally produced by electrolytically depositing copper from a copper sulfate plating bath onto a titanium or stainless steel drum. It has a flat S-side (shine side) formed on the rotating drum side and an M-side (matte side) formed on the opposite side of the S-side. The M-side of electrodeposited copper foil generally has minute irregularities. Furthermore, the S-side of electrodeposited copper foil also has minute irregularities due to the transfer of polishing marks from the rotating drum during polishing. Rolled copper foil has minute irregularities on its surface due to the formation of oil pits by rolling oil during rolling.

[0040] The material of the copper foil is not particularly limited. When the copper foil is a rolled copper foil, high-purity copper such as tough pitch copper (JIS H3100 alloy number C1100) or oxygen-free copper (JIS H3100 alloy number C1020 or JIS H3510 alloy number C1011), which are commonly used for circuit patterns on printed wiring boards, can be used. Also usable are copper alloys such as Sn-containing copper, Ag-containing copper, copper alloys containing Cr, Zr, or Mg, and Corson copper alloys containing Ni and Si. In this specification, the term "copper foil" is intended to encompass copper alloy foils.

[0041] When the copper foil is a rolled copper foil, the rolled copper foil may have a composition containing 99.0 mass% or more of Cu and 0.003 to 0.825 mass% of one or more elements selected from the group consisting of P, Ti, Sn, Ni, Be, Zn, In, and Mg, with the balance being unavoidable impurities. Alternatively, the rolled copper foil may have a composition containing 99.9 mass% or more of Cu and 0.0005 to 0.0220 mass% of P, with the balance being unavoidable impurities. Furthermore, the rolled copper foil may have a composition containing 99.0 mass% or more of Cu and the balance being unavoidable impurities. When the copper foil is a rolled copper foil, the average crystal grain size may be 0.5 to 4.0 μm, and the tensile strength in the rolling direction may be 235 to 290 MPa. Furthermore, the rolled copper foil may have a conductivity of 75% IACS or more. The conductivity of the copper foil can be measured at room temperature (25°C) by the four-terminal method in accordance with JIS H0505 (1975).

[0042] The thickness of the copper foil is not particularly limited, but can be, for example, 1 to 1000 μm, 1 to 500 μm, 1 to 300 μm, 3 to 100 μm, 5 to 70 μm, 6 to 35 μm, or 9 to 18 μm.

[0043] The surface-treated copper foil having the above-described configuration can be produced according to a method known in the art. Here, the surface property parameters such as Vmc of the surface treatment layer can be controlled by adjusting the formation conditions of the surface treatment layer, particularly the formation conditions of the roughening treatment layer.

[0044] In the surface-treated copper foil according to the embodiment of the present invention, the Vmc of the surface treatment layer is 0.35 to 0.55 μm. 3 / μm 2 Since the adhesiveness is controlled to be within the range of 1000 to 15000 kJ / cm, it is possible to improve the adhesiveness to a resin substrate, particularly a resin substrate suitable for high frequency applications.

[0045] A copper clad laminate according to an embodiment of the present invention comprises the above-described surface-treated copper foil and a resin substrate adhered to the surface treatment layer of the surface-treated copper foil. This copper-clad laminate can be produced by adhering a resin substrate to the surface-treated layer of the above-mentioned surface-treated copper foil. The resin substrate is not particularly limited, and those known in the art can be used. Examples of the resin substrate include a paper substrate with a phenolic resin, a paper substrate with an epoxy resin, a synthetic fiber cloth substrate with an epoxy resin, a glass cloth / paper composite substrate with an epoxy resin, a glass cloth / glass nonwoven fabric composite substrate with an epoxy resin, a glass cloth substrate with an epoxy resin, a polyester film, a polyimide resin, a liquid crystal polymer, and a fluororesin. Among these, a polyimide resin is preferred as the resin substrate. Furthermore, resin substrates particularly suitable for high-frequency applications include those made of low-dielectric materials. Examples of low-dielectric materials include liquid crystal polymers, low-dielectric polyimides, and fluororesins. The low-dielectric material may be, for example, a material having a dielectric constant of 3.5 or less at 1 MHz. The low-dielectric material suitable for high-frequency applications may be a material having a dielectric constant of 3.4 or less at 30 GHz.

[0046] The method for bonding the surface-treated copper foil to the resin substrate is not particularly limited and can be performed according to a method known in the art. For example, the surface-treated copper foil and the resin substrate may be laminated and thermocompressed together. The copper clad laminate produced as described above can be used in the production of printed wiring boards.

[0047] The copper clad laminate according to the embodiment of the present invention uses the above-mentioned surface-treated copper foil, and therefore can improve adhesion to resin substrates, particularly resin substrates suitable for high frequency applications.

[0048] A printed wiring board according to an embodiment of the present invention includes a circuit pattern formed by etching the surface-treated copper foil of the above-described copper-clad laminate. This printed wiring board can be produced by etching the surface-treated copper foil of the copper-clad laminate to form a circuit pattern. The method for forming the circuit pattern is not particularly limited, and known methods such as subtractive and semi-additive methods can be used. Among these, the subtractive method is preferred as the method for forming the circuit pattern.

[0049] When a printed wiring board is manufactured by the subtractive method, it is preferably carried out as follows. First, a resist is applied to the surface of the surface-treated copper foil of a copper-clad laminate, and a predetermined resist pattern is formed by exposure and development. Next, the surface-treated copper foil in the areas where the resist pattern is not formed (i.e., unnecessary areas) is removed by etching to form a circuit pattern. Finally, the resist pattern on the surface-treated copper foil is removed. The conditions for this subtractive method are not particularly limited, and the method can be carried out according to conditions known in the art.

[0050] The printed wiring board according to the embodiment of the present invention uses the above-mentioned copper-clad laminate, and therefore has excellent adhesion between the resin substrate, particularly a resin substrate suitable for high frequency applications, and the circuit pattern. [Example]

[0051] Hereinafter, the embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples in any way.

[0052] (Example 1) A rolled copper foil with a thickness of 12 μm (HG foil manufactured by JX Metals Co., Ltd.) was prepared. After degreasing and pickling both sides of the copper foil, a surface-treated copper foil was obtained by sequentially forming a roughened treatment layer, a chemical-resistant treatment layer (Co-Ni layer), a heat-resistant treatment layer (Ni-Zn layer), a chromate treatment layer, and a silane coupling treatment layer on one side (hereinafter referred to as the "first side") as the surface treatment layer. The formation conditions for each treatment layer were as follows. (1) Roughened treatment layer / first side (Formation conditions for primary roughened particles) Plating solution composition: 12 g / L of Cu, 50 g / L of sulfuric acid, 5 ppm of tungsten (derived from sodium tungstate dihydrate) Plating solution temperature: 27 °C Electroplating conditions: Current density 39.5 A / dm 2 , time 1.2 seconds Number of electroplating treatments: 2 times<()000349>

[0053] (Formation conditions for the overlay plating layer) Plating solution composition: 20 g / L of Cu, 100 g / L of sulfuric acid Plating solution temperature: 50 °C Electroplating conditions: Current density 9.6 A / dm 2 , time 1.8 seconds Number of electroplating treatments: 2 times

[0054] (Formation conditions for secondary roughened particles) Plating solution composition: 15.5 g / L of Cu, 7.5 g / L of Co, 9.5 g / L of Ni Plating solution temperature: 50 °C Electroplating conditions: Current density 33.3 A / dm 2 , time 0.55 seconds Number of electroplating treatments: 2 times

[0055] (2) Chemical-resistant treatment layer / first side (Formation conditions for the Co-Ni layer)<()000367>Plating solution composition: 3 g / L of Co, 13 g / L of Ni Plating solution pH: 2.0 Plating solution temperature: 50 °C Electroplating conditions: Current density 4.5 A / dm 2 , Time 0.48 seconds Number of electroplating treatments: 1 time

[0056] (3) Heat-resistant treatment layer / First surface<OO00375><Formation conditions of Ni-Zn layer> Plating solution composition: 23.5 g / L of Ni, 4.5 g / L of Zn pH of plating solution: 3.6 Plating solution temperature: 40 °C Electroplating conditions: Current density 0.7 A / dm 2 , Time 0.90 seconds Number of electroplating treatments: 1 time

[0057] (4) Chromate treatment layer / First surface <Formation conditions of electrolytic chromate treatment layer> Chromate solution composition: 3 g / L of K2Cr2O7, 0.33 g / L of Zn pH of chromate solution: 3.7 Chromate solution temperature: 55 °C Electrolysis conditions: Current density 1.2 A / dm 2 , Time �.90 seconds Number of chromate treatments: 2 times

[0058] (5) Silane coupling treatment layer / First surface A 1.2% by volume aqueous solution of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane was applied and dried to form a silane coupling treatment layer. [[ID=A7]]

[0059] (Example 2) In the formation conditions of the primary roughened particles, the electroplating conditions were changed to a current density of 43.7 A / dm 2 , and in the formation conditions of the overlay plating layer, the electroplating conditions were changed to a current density of 12.3 A / dm 2 , Time 1.8 seconds. Except for these changes, a surface-treated copper foil was obtained under the same conditions as in Example 1.

[0060] (Example 3) The conditions for forming the heat-resistant layer (Ni-Zn layer) on the first surface were electroplating conditions with a current density of 0.5 A / dm 2 A surface-treated copper foil was obtained under the same conditions as in Example 1, except that the heating time was changed to 0.90 seconds.

[0061] Example 4 No heat-resistant layer was formed on the first surface, and the chemical-resistant layer (Co-Ni layer) was formed under the electroplating conditions of a current density of 3.0 A / dm 2 A surface-treated copper foil was obtained under the same conditions as in Example 1, except for changing the temperature.

[0062] Example 5 No heat-resistant layer was formed on the first surface, and the electroplating conditions for the formation of the primary roughening particles were set to a current density of 35.2 A / dm 2 In addition, the electroplating conditions for forming the chemical-resistant layer (Co-Ni layer) were changed to a current density of 3.0 A / dm 2 A surface-treated copper foil was obtained under the same conditions as in Example 1, except for changing the temperature.

[0063] Example 6 No heat-resistant layer was formed on the first surface, and the electroplating conditions for the formation of the primary roughening particles were set at a current density of 42.9 A / dm 2 In addition, the electroplating conditions for forming the chemical-resistant layer (Co-Ni layer) were changed to a current density of 3.0 A / dm 2 A surface-treated copper foil was obtained under the same conditions as in Example 1, except for changing the temperature.

[0064] Example 7 No heat-resistant layer was formed on the first surface, and the electroplating conditions for the formation of the primary roughening particles were set at a current density of 46.7 A / dm 2 In addition, the electroplating conditions for forming the chemical-resistant layer (Co-Ni layer) were changed to a current density of 3.0 A / dm 2 A surface-treated copper foil was obtained under the same conditions as in Example 1, except for changing the temperature.

[0065] Example 8 No heat-resistant layer was formed on the first surface, and the electroplating conditions for forming secondary roughening particles were set at a current density of 28.9 A / dm 2 In addition, the electroplating conditions for forming the chemical-resistant layer (Co-Ni layer) were changed to a current density of 3.0 A / dm 2 A surface-treated copper foil was obtained under the same conditions as in Example 1, except for changing the temperature.

[0066] Example 9 No heat-resistant layer was formed on the first surface, and the electroplating conditions for forming secondary roughening particles were set at a current density of 37.7 A / dm 2 In addition, the electroplating conditions for forming the chemical-resistant layer (Co-Ni layer) were changed to a current density of 3.0 A / dm 2 A surface-treated copper foil was obtained under the same conditions as in Example 1, except for changing the temperature.

[0067] Example 10 No heat-resistant layer was formed on the first surface, and the electroplating conditions for forming secondary roughening particles were set at a current density of 42.1 A / dm 2 In addition, the electroplating conditions for forming the chemical-resistant layer (Co-Ni layer) were changed to a current density of 3.0 A / dm 2 A surface-treated copper foil was obtained under the same conditions as in Example 1, except for changing the temperature.

[0068] (Comparative Example 1) A 12 μm thick rolled copper foil (HG foil manufactured by JX Nippon Mining & Metals Corporation) was prepared, and after degreasing and pickling on both sides, a roughening treatment layer, a chemical-resistant treatment layer (Co-Ni layer), a heat-resistant treatment layer (Ni-Zn layer), a chromate treatment layer, and a silane coupling treatment layer were sequentially formed on one side (first side) as surface treatment layers to obtain a surface-treated copper foil. The conditions for forming each treatment layer were as follows: (1) Roughened layer / first surface <Conditions for forming primary roughening particles> Plating solution composition: 12 g / L Cu, 50 g / L sulfuric acid, 5 ppm tungsten (derived from sodium tungstate dihydrate) Plating solution temperature: 27℃ Electroplating conditions: Current density 46 A / dm 2 , Time 1.2 seconds Number of electroplating treatments: 2 times

[0069] <Conditions for forming the overlay plating layer> Plating solution composition: 20 g / L of Cu, 100 g / L of sulfuric acid Plating solution temperature: 50 °C Electroplating conditions: Current density 9.6 A / dm 2 , Time 1.8 seconds Number of electroplating treatments: 2 times

[0070] (2) Chemical-resistant treatment layer / First surface <Conditions for forming the Co-Ni layer> Plating solution composition: 3 g / L of Co, 13 g / L of Ni Plating solution pH: 2.0 Plating solution temperature: 50 °C Electroplating conditions: Current density 4.5 A / dm 2 , Time 0.48 seconds Number of electroplating treatments: 1 time

[0071] (3) Heat-resistant treatment layer / First surface <Conditions for forming the Ni-Zn layer> Plating solution composition: 23.5 g / L of Ni, 4.5 g / L of Zn Plating solution pH: 3.6 Plating solution temperature: 40 °C Electroplating conditions: Current density 0.9 A / dm 2 , Time 0.90 seconds Number of electroplating treatments: 1 time

[0072] (4) Chromate treatment layer / First surface <Conditions for forming the electrolytic chromate treatment layer><I Chromate solution composition: 3 g / L of K2Cr2O7, 0.33 g / L of Zn Chromate solution pH: 3.7 Chromate solution temperature: 55 °C Electrolysis conditions: Current density 1.2 A / dm 2 , Time 0.90 seconds Number of chromate treatments: 2 times

[0073] (5) Silane coupling treatment layer / first surface A 1.2% by volume aqueous solution of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane was applied and dried to form a silane coupling treatment layer.

[0074] (Comparative Example 2) A 12 μm thick rolled copper foil (HG foil manufactured by JX Nippon Mining & Metals Corporation) was prepared, and after degreasing and pickling on both sides, a roughening treatment layer, a chemical-resistant treatment layer (Co-Ni layer), a chromate treatment layer, and a silane coupling treatment layer were sequentially formed on one side (first side) as surface treatment layers to obtain a surface-treated copper foil. The conditions for forming each treatment layer were as follows: (1) Roughened layer / first surface <Conditions for forming primary roughening particles> Plating solution composition: 12g / L Cu, 50g / L sulfuric acid Plating solution temperature: 25℃ Electroplating conditions: current density 45A / dm 2 , time 0.68 seconds Number of electroplating treatments: 2

[0075] <Conditions for forming the cover plating layer> Plating solution composition: 20g / L Cu, 100g / L sulfuric acid Plating solution temperature: 50℃ Electroplating conditions: current density 4.9A / dm 2 , time 0.77 seconds Number of electroplating treatments: 2

[0076] <Conditions for forming secondary roughening particles> Plating solution composition: 15.5g / L Cu, 7.5g / L Co, 9.5g / L Ni Plating solution temperature: 50℃ Electroplating conditions: current density 31.2A / dm 2 , time 0.37 seconds Number of electroplating treatments: 3 times

[0077] (2) Chemical-resistant layer / first surface <Formation Conditions of Co-Ni Layer> Plating solution composition: 3 g / L of Co, 13 g / L of Ni pH of plating solution: 2.0 Temperature of plating solution: 50 °C Electroplating conditions: Current density 3.2 A / dm 2 , time 0.37 seconds Number of electroplating treatments: 1 time (3) Chromate treatment layer / First surface <Formation Conditions of Electrolytic Chromate Treatment Layer> Chromate solution composition: 3 g / L of K2Cr2O7, 0.33 g / L of Zn pH of chromate solution: 3.7 Temperature of chromate solution: 55 °C Electrolysis conditions: Current density 2.7 A / dm 2 , time 0.39 seconds Number of chromate treatments: 2 times

[0078] (4) Silane coupling treatment layer / First surface A 1.2% by volume aqueous solution of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane was applied and dried to form a silane coupling treatment layer.

[0079] For the surface-treated copper foils obtained in the above Examples and Comparative Examples, the following characteristic evaluations were performed. <Vmc, Sk, and Ssk of the Surface Treatment Layer (First Surface)> Imaging was performed using a laser microscope (LEXT OLS4000) manufactured by Olympus Corporation. Analysis of the captured images was performed using the analysis software of a laser microscope (LEXT OLS4100) manufactured by Olympus Corporation. Measurement of Vmc, Sk, and Ssk of the surface treatment layer was performed in accordance with ISO 25178-2:2012. Also, the average value of the values measured at 10 arbitrary locations was used as the measurement result for these measurements. The temperature during measurement was set to 23 - 25 °C. The main setting conditions for the laser microscope and analysis software are as follows. Objective lens: MPLAPON50XLEXT (Magnification: 50x, Numerical Aperture: 0.95, Immersion Type: Air, Mechanical Tube Length: ∞, Cover Glass Thickness: 0, Field Number: FN18) Optical zoom magnification: 1x Scanning mode: XYZ high precision (height resolution: 60 nm, number of pixels of captured data: 1024 x 1024) Captured image size [pixels]: 257 μm wide x 258 μm high [1024 x 1024] (As the measurement is made in the horizontal direction, the evaluation length is equivalent to 257 μm) DIC: Off Multilayer: Off Laser Intensity: 100 Offset: 0 Confocal level: 0 Beam diameter aperture: Off Image average: 1 time Noise reduction: On Brightness correction: On Optical noise filter: On Cutoff: λc=200μm, λs and λf are none Filter: Gaussian filter Noise reduction: Measurement preprocessing Surface (tilt) correction: Implemented Brightness: Adjust to a range of 30-50 The brightness should be set appropriately depending on the color tone of the object to be measured. The above settings are appropriate for measuring the surface of surface-treated copper foil with L* of -69 to -10, a* of 2 to 32, and b* of 2 to 21.

[0080] <Measuring the color tone of the object> The measurement instrument used was a MiniScan (registered trademark) EZ Model 4000L manufactured by HunterLab, and measurements of L*, a*, and b* in the CIE L*a*b* color system were carried out in accordance with JIS Z8730:2009. Specifically, the measurement surface of the surface-treated copper foil obtained in the above Examples and Comparative Examples was pressed against the photosensitive part of the measurement instrument, and measurements were carried out while preventing light from entering from outside. Furthermore, measurements of L*, a*, and b* were carried out based on geometric condition C of JIS Z8722:2009. The main conditions of the measurement instrument are as follows: Optical system: d / 8°, integrating sphere size: 63.5mm, observation light source: D65 Measurement method: reflection Lighting diameter: 25.4mm Measuring diameter: 20.0 mm Measurement wavelength / interval: 400~700nm / 10nm Light source: Pulsed xenon lamp, 1 light emission / measurement Traceability standards: National Institute of Standards and Technology (NIST) compliant calibration based on CIE 44 and ASTM E259 Standard observer: 10° The white tiles used as the measurement standards were the following object colors: When measured at D65 / 10°, the CIE XYZ color system values ​​are X: 81.90, Y: 87.02, and Z: 93.76

[0081] <Peel strength> After laminating the surface-treated copper foil (first surface side) to a resin substrate made of a low-dielectric material, a 3 mm-wide circuit was formed in the MD direction (the longitudinal direction of the rolled copper foil). The circuit was formed according to a conventional method. Next, the strength (MD 180° peel strength) when the circuit (surface-treated copper foil) was peeled from the surface of the resin substrate in a 180° direction, i.e., in the MD direction, at a speed of 50 mm / min was measured in accordance with JIS C6471:1995. Five measurements were performed, and the average value was used as the peel strength result. A peel strength of 0.60 kgf / cm or higher indicates good adhesion between the circuit (surface-treated copper foil) and the resin substrate.

[0082] The results of the above characteristic evaluation are shown in Table 1.

[0083] [Table 1]

[0084] As shown in Table 1, the Vmc of the surface treatment layer is 0.35 to 0.55 μm. 3 / μm 2 The surface-treated copper foils of Examples 1 to 10, which had a Vmc of the surface treatment layer outside the specified range, had higher peel strength than those of Comparative Examples 1 and 2, which had a Vmc of the surface treatment layer outside the specified range.

[0085] Next, we investigated the effect of the amount of Zn deposited in the surface treatment layer on solder heat resistance.

[0086] Example 11 A surface-treated copper foil was obtained under the same conditions as in Example 1, except that no heat-resistant layer was formed on the first surface and that the immersion was carried out under the conditions for forming a chromate treatment layer without applying a current.

[0087] Example 12 No heat-resistant layer was formed on the first surface, and the electroplating conditions for forming the chromate layer were set at a current density of 0.64 A / dm 2 A surface-treated copper foil was obtained under the same conditions as in Example 1, except for changing the temperature.

[0088] Example 13 No heat-resistant layer was formed on the first surface, and the electroplating conditions for forming the chromate layer were set at a current density of 1.4 A / dm 2 A surface-treated copper foil was obtained under the same conditions as in Example 1, except for changing the temperature.

[0089] For the surface-treated copper foils obtained in the above examples, Vmc, Sk, Ssk and peel strength were measured in the same manner as above, and the following evaluations were also made.

[0090] <Measurement of Zn adhesion amount on the surface treatment layer (first side)> The amount of Zn attached to the surface treatment layer (first side) was measured by dissolving the surface treatment layer (first side) in 20 mass% nitric acid and performing quantitative analysis by atomic absorption spectrometry using an atomic absorption spectrophotometer (AA240FS, manufactured by VARIAN).

[0091] <Solder heat resistance> The surface-treated copper foil was laminated to a resin substrate made of a low-dielectric material, and then etched to a size of 25 mm x 25 mm. Circuit formation was performed according to standard methods. Next, the sample was placed in a thermo-hygrostat and maintained at 85°C and 85% relative humidity for 48 hours. The sample was then floated in a solder bath containing solder at a specified temperature and removed after 30 seconds. The sample circuit was visually inspected for the presence of bubbles. If no bubbles were observed in the sample circuit, another sample was prepared, the solder temperature in the solder bath was increased, and the presence of bubbles in the sample circuit was inspected again. This procedure was repeated until bubbles appeared in the sample circuit. The evaluation results were expressed as the maximum temperature at which no bubbles were observed in the sample circuit. If the maximum temperature at which no bubbles were observed in the sample circuit was 290°C or higher, the sample had good solder heat resistance.

[0092] [Table 2]

[0093] As shown in Table 2, the surface-treated copper foils of Examples 11 to 13 had a Vmc of the surface treatment layer in the range of 0.35 to 0.55 μm, similar to the surface-treated copper foils of Examples 1 to 10, and therefore had higher peel strength than the surface-treated copper foils of Comparative Examples 1 and 2. In addition, the surface-treated copper foils of Examples 11 to 13 had a Zn coating weight of 6 to 200 μm / dm 2 In particular, the Zn adhesion was 82 to 200 μm / dm 2 Examples 12 and 13, in which the soldering heat resistance was particularly excellent.

[0094] As can be seen from the above results, according to an embodiment of the present invention, a surface-treated copper foil capable of improving adhesion to a resin substrate, particularly a resin substrate suitable for high-frequency applications, can be provided. Furthermore, according to an embodiment of the present invention, a copper-clad laminate having excellent adhesion between a resin substrate, particularly a resin substrate suitable for high-frequency applications, and the surface-treated copper foil can be provided. Furthermore, according to an embodiment of the present invention, a printed wiring board having excellent adhesion between a resin substrate, particularly a resin substrate suitable for high-frequency applications, and a circuit pattern can be provided.

[0095] Therefore, the embodiment of the present invention can have the following aspects. [1] A copper foil and a surface treatment layer formed on at least one surface of the copper foil, The core volume Vmc of the surface treatment layer is 0.35 to 0.55 μm 3 / μm 2 This is surface-treated copper foil. [2] The core's substantial volume Vmc is 0.37 to 0.52 μm 3 / μm 2 The surface-treated copper foil according to [1], [3] The core's substantial volume Vmc is 0.38 to 0.45 μm 3 / μm 2 The surface-treated copper foil according to [1], [4] The surface-treated copper foil according to any one of [1] to [3], wherein the level difference Sk of the core part of the surface treatment layer is 0.70 to 1.50 μm. [5] The surface-treated copper foil according to any one of [1] to [3], wherein the level difference Sk of the core part of the surface treatment layer is 0.85 to 1.30 μm. [6] The surface-treated copper foil according to any one of [1] to [3], wherein the level difference Sk of the core part of the surface treatment layer is 1.03 to 1.18 μm. [7] The surface-treated copper foil according to any one of [1] to [6], wherein the skewness Ssk of the surface treatment layer is 0.10 to 1.00. [8] The surface-treated copper foil according to any one of [1] to [6], wherein the skewness Ssk of the surface treatment layer is 0.30 to 0.90. [9] The surface-treated copper foil according to any one of [1] to [6], wherein the skewness Ssk of the surface treatment layer is 0.45 to 0.80.

[10] The Zn coating weight of the surface treatment layer is 6 to 200 μm / dm 2 The surface-treated copper foil according to any one of [1] to [9], wherein

[11] The Zn coating weight of the surface treatment layer is 82 to 200 μm / dm 2 The surface-treated copper foil according to

[10] ,

[12] The surface-treated copper foil according to any one of [1] to

[11] , wherein the surface treatment layer contains a roughening treatment layer.

[13] A copper-clad laminate comprising the surface-treated copper foil according to any one of [1] to

[12] and a resin substrate adhered to the surface treatment layer of the surface-treated copper foil.

[14] A printed wiring board comprising a circuit pattern formed by etching the surface-treated copper foil of the copper-clad laminate according to

[13] . [Explanation of symbols]

[0096] 10 Copper foil 20 Primary roughening particles 30 Cover plating layer 40 Secondary roughening particles

Claims

1. A copper foil and a surface treatment layer formed on at least one surface of the copper foil, The substantial volume Vmc of the core portion of the surface treatment layer is 0.35 to 0.55 μm 3 / μm 2 and The surface-treated copper foil has a level difference Sk of 0.70 to 1.50 μm between the core and surface-treated layers.

2. A substrate comprising a copper foil and a surface treatment layer formed on at least one surface of the copper foil, the core portion of the surface treatment layer has a substantial volume Vmc of 0.35 to 0.55 μm 3 / μm 2 ; The surface-treated copper foil has a skewness Ssk of 0.10 to 1.

00.

3. A copper foil and a surface treatment layer formed on at least one surface of the copper foil, the core portion of the surface treatment layer has a substantial volume Vmc of 0.35 to 0.55 μm 3 / μm 2 ; The surface-treated copper foil has a Zn coating weight of 6 to 200 μm / dm 2 in the surface treatment layer.

4. The core's substantial volume Vmc is 0.37 to 0.52 μm 3 / μm 2 The surface-treated copper foil according to any one of claims 1 to 3,

5. The core's substantial volume Vmc is 0.38 to 0.45 μm 3 / μm 2 The surface-treated copper foil according to any one of claims 1 to 3,

6. The surface-treated copper foil according to claim 2, wherein the level difference Sk of the core portion of the surface treatment layer is 0.70 to 1.50 μm.

7. A surface-treated copper foil as described in claim 3, wherein the level difference Sk of the core portion of the surface treatment layer is 0.70 to 1.50 μm.

8. The surface-treated copper foil according to any one of claims 1, 6 and 7, wherein the level difference Sk of the core portion of the surface treatment layer is 0.85 to 1.30 µm.

9. The surface-treated copper foil according to any one of claims 1, 6 and 7, wherein the level difference Sk of the core portion of the surface treatment layer is 1.03 to 1.18 µm.

10. The surface-treated copper foil according to claim 3, wherein the skewness Ssk of the surface treatment layer is 0.10 to 1.

00.

11. The surface-treated copper foil according to claim 2 or 10, wherein the skewness Ssk of the surface treatment layer is 0.30 to 0.

90.

12. The surface-treated copper foil according to claim 2 or 10, wherein the skewness Ssk of the surface treatment layer is 0.45 to 0.

80.

13. The Zn deposition amount in the surface treatment layer is 82 to 200 μm / dm 2 The surface-treated copper foil according to any one of claims 3, 7 and 10, wherein

14. The surface-treated copper foil according to any one of claims 1 to 3, wherein the surface treatment layer contains a roughening treatment layer.

15. A copper-clad laminate comprising the surface-treated copper foil according to any one of claims 1 to 3 and a resin substrate adhered to the surface treatment layer of the surface-treated copper foil.

16. A printed wiring board comprising a circuit pattern formed by etching the surface-treated copper foil of the copper-clad laminate according to claim 15.

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