JP2015105440A - Surface treated copper foil, laminate, printed wiring board, printed circuit board and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a surface treated copper foil capable of favorably suppressing transmission loss even when used for a high frequency circuit board; a laminate; a printed wiring board; a printed circuit board; and an electronic apparatus.SOLUTION: The surface treated copper foil has a surface treated layer formed on at least one surface. The surface treated layer includes a roughened layer, and the total coating weight of Co, Ni and Fe in the surface treated layer is 986 μg/dmor less, preferably 300 μg/dmor less and more preferably 0 μg/dm. The surface treated layer has a Zn metal layer or an alloyed layer including Zn. A ratio of a three-dimensional surface area to a two-dimensional surface area measured on the surface of the surface treated layer by a laser microscope is 1.0-1.9, and the surface roughness Rz JIS of the at least one surface is 2.2 μm or less.

Description

  The present invention relates to a surface-treated copper foil, a laminated board, a printed wiring board, a printed circuit board, and an electronic device, and more particularly to a surface-treated copper foil, a laminated board, a printed wiring board, a printed circuit board, and an electronic device suitable for high-frequency circuit board applications. .

  Printed wiring boards have made great progress over the last half century and are now used in almost all electronic devices. In recent years, with the increasing demand for miniaturization and high performance of electronic devices, high density mounting of mounted components and high frequency of signals have progressed, and excellent high frequency response is required for printed wiring boards.

  The high frequency board is required to reduce transmission loss in order to ensure the quality of the output signal. The transmission loss mainly consists of a dielectric loss due to the resin (substrate side) and a conductor loss due to the conductor (copper foil side). The dielectric loss decreases as the dielectric constant and dielectric loss tangent of the resin decrease. In a high-frequency signal, the conductor loss is mainly caused by a decrease in the cross-sectional area through which the current flows due to the skin effect that only the surface of the conductor flows as the frequency increases, and the resistance increases.

  As a technique for reducing the transmission loss of the high-frequency copper foil, for example, in Patent Document 1, silver or a silver alloy metal is coated on one or both surfaces of the metal foil surface, and on the silver or silver alloy coating layer, A metal foil for a high frequency circuit is disclosed in which a coating layer other than silver or silver alloy is applied thinner than the thickness of the silver or silver alloy coating layer. And according to this, it is described that it is possible to provide a metal foil in which the loss due to the skin effect is reduced even in an ultra-high frequency region used in satellite communications.

Patent Document 2 discloses that the integrated intensity (I (200)) of (200) plane obtained by X-ray diffraction on the rolled surface after recrystallization annealing of the rolled copper foil is the X-ray diffraction of fine powder copper. The obtained integrated strength (I ₀ (200)) of the (200) plane is I (200) / I ₀ (200)> 40, and the rolled surface is subjected to roughening treatment by electrolytic plating. The arithmetic average roughness (hereinafter referred to as Ra) of the chemical treatment surface is 0.02 μm to 0.2 μm, the ten-point average roughness (hereinafter referred to as Rz) is 0.1 μm to 1.5 μm, and the printed circuit A roughened rolled copper foil for high-frequency circuits, which is a substrate material, is disclosed. And it is described that according to this, the printed circuit board which can be used under the high frequency exceeding 1 GHz can be provided.

  Furthermore, Patent Document 3 discloses an electrolytic copper foil characterized in that a part of the surface of the copper foil is an uneven surface having a surface roughness of 2 to 4 μm made of bump-shaped protrusions. And according to this, it describes that the electrolytic copper foil excellent in the high frequency transmission characteristic can be provided.

Japanese Patent No. 4161304 Japanese Patent No. 4770425 JP 2004-244656 A

  The conductor loss due to the conductor (copper foil side) is caused by the increase in resistance due to the skin effect as described above. This resistance is not only the resistance of the copper foil itself but also the resin substrate on the copper foil surface. There is also the influence of the resistance of the surface treatment layer formed by the roughening process performed to ensure the adhesion of the copper, specifically, the roughness of the copper foil surface is the main factor of the conductor loss, the roughness It is known that the transmission loss decreases as the value decreases.

  Moreover, when performing a roughening process as a surface treatment of copper foil, using a Cu-Ni alloy process or a Cu-Co-Ni alloy process, and performing a heat-resistant process and a rust prevention process, Ni-Zn alloy process or Co-Ni It is common to use alloy processing.

  However, Co and Ni commonly used in the above roughening treatment, heat treatment and rust prevention treatment, and Fe, are metals that exhibit ferromagnetism at room temperature, and when they are contained as components in the surface treatment layer, the influence of magnetism As a result, the current distribution and the magnetic field distribution in the conductor are affected, and the transmission characteristics of the copper foil deteriorate.

  It is an object of the present invention to provide a surface-treated copper foil, a laminated board, a printed wiring board, a printed circuit board, and an electronic device in which transmission loss is satisfactorily suppressed even when used for a high-frequency circuit board.

  In order to suppress the influence of the ferromagnetic metal on the transmission characteristics, the inventor controls the total adhesion amount of Co, Ni, and Fe in the surface treatment layer of the copper foil to a predetermined amount or less, and as an alternative component It was found that high-frequency transmission loss can be further reduced by containing Zn that does not exhibit ferromagnetism at room temperature. Furthermore, in addition to the surface roughness Rz managed by the conventional high-frequency copper foil, the ratio of the three-dimensional surface area to the two-dimensional surface area that more accurately represents the contact area with the resin (dielectric material) is prominent in transmission loss. I found it to have an impact.

The present invention completed on the basis of the above knowledge is, in one aspect, a surface-treated copper foil in which a surface-treated layer is formed on at least one surface, the surface-treated layer including a roughened layer, and the surface The total adhesion amount of Co, Ni, and Fe in the treatment layer is 300 μg / dm ² or less, the surface treatment layer has a Zn metal layer or an alloy treatment layer containing Zn, and measured with a laser microscope on the surface of the surface treatment layer The surface-treated copper foil has a ratio of a three-dimensional surface area to a two-dimensional surface area of 1.0 to 1.9 and a surface roughness Rz JIS of at least one surface of 2.2 μm or less.

In one embodiment of the surface-treated copper foil of the present invention, the total adhesion amount of Co, Ni, and Fe in the surface-treated layer is 0 μg / dm ² .

  In another embodiment of the surface-treated copper foil of the present invention, the surface-treated layers are formed on both surfaces, and the surface roughness Rz JIS of both surfaces is 2.2 μm or less.

In another aspect, the surface-treated copper foil of the present invention is a surface-treated copper foil in which a surface-treated layer is formed on at least one surface, and a total adhesion amount of Co, Ni, and Fe in the surface-treated layer is 986 μg. / Dm ² or less, the surface treatment layer has a Zn metal layer or an alloy treatment layer containing Zn, and the ratio of the three-dimensional surface area to the two-dimensional surface area measured by a laser microscope on the surface of the surface treatment layer is 1. This is a surface-treated copper foil having a surface roughness Rz JIS of 0.6 μm or less at 0 to 1.9.

  In another embodiment of the surface-treated copper foil of the present invention, the surface-treated layer includes a roughened layer.

  In yet another embodiment of the surface-treated copper foil of the present invention, the surface-treated layers are formed on both surfaces, and the surface roughness Rz JIS of both surfaces is 0.6 μm or less.

In still another embodiment of the surface-treated copper foil of the present invention, the amount of Cu deposited on the roughened layer is 0.10 g / dm ² or less.

  In still another embodiment of the surface-treated copper foil of the present invention, in the surface-treated layer, the Zn metal layer or an alloy-treated layer containing Zn is provided on the roughened layer.

  In still another embodiment of the surface-treated copper foil of the present invention, the alloy-treated layer containing Zn is a Cu—Zn alloy layer.

In still another embodiment of the surface-treated copper foil of the present invention, the amount of Zn deposited on the surface-treated layer is 5 mg / dm ² or less.

  In still another embodiment of the surface-treated copper foil of the present invention, a chromate treatment layer is provided on the surface treatment layer on the Zn metal layer or the alloy treatment layer containing Zn.

  In another embodiment of the surface-treated copper foil of the present invention, a silane coupling treatment layer is provided on the chromate treatment layer.

In still another embodiment of the surface-treated copper foil of the present invention, the total adhesion amount of Cu, Zn, Co, Ni, and Fe in the surface-treated layer is 0.10 g / dm ² or less.

  In still another embodiment, the surface-treated copper foil of the present invention is for a flexible printed wiring board.

  In yet another embodiment, the surface-treated copper foil of the present invention is for a high-frequency circuit board of 5 GHz or more.

  In still another aspect of the present invention, the present invention is a laminated plate configured by laminating the surface-treated copper foil of the present invention and a resin substrate.

  In yet another aspect, the present invention is a printed wiring board made from the laminated board of the present invention.

  In still another aspect, the present invention is a printed circuit board made from the laminate of the present invention.

  In still another aspect, the present invention is an electronic device using the printed circuit board of the present invention.

  According to the present invention, it is possible to provide a surface-treated copper foil, a laminated board, a printed wiring board, a printed circuit board, and an electronic device in which transmission loss is satisfactorily suppressed even when used for a high-frequency circuit board.

It is a graph which shows the relationship between the total adhesion amount of Co, Ni, and Fe which concerns on an Example and a comparative example, and surface roughness Rz. It is a graph which shows the relationship between the total adhesion amount of Co, Ni, and Fe which concerns on an Example and a comparative example, and the ratio of the three-dimensional surface area with respect to a two-dimensional surface area. It is a graph which shows the relationship between the total adhesion amount of Co, Ni, Fe, Cu, and Zn which concerns on an Example and a comparative example, and transmission loss.

(Copper foil base material)
Although there is no restriction | limiting in particular in the form of the copper foil base material which can be used for this invention, Typically, it can use with the form of rolled copper foil or electrolytic copper foil. In general, the electrolytic copper foil is produced by electrolytic deposition of copper from a copper sulfate plating bath onto a drum of titanium or stainless steel, and the rolled copper foil is produced by repeating plastic working and heat treatment with a rolling roll. Rolled copper foil is often used for applications that require flexibility.
In addition to high-purity copper such as tough pitch copper and oxygen-free copper, which are usually used as conductor patterns for printed wiring boards, for example, Sn-containing copper, Ag-containing copper, Cr, Zr or Mg are added as the copper foil base material. It is also possible to use a copper alloy such as a copper alloy, a Corson copper alloy to which Ni, Si and the like are added. In addition, when the term “copper foil” is used alone in this specification, a copper alloy foil is also included. When a copper alloy foil is used as the copper foil for the high-frequency circuit board, it is preferable that the electrical resistivity does not increase remarkably as compared with copper.
The plate thickness of the copper foil base material is not particularly limited, but is, for example, 1 to 300 μm, alternatively 3 to 100 μm, alternatively 5 μm to 70 μm, alternatively 6 μm to 35 μm, alternatively 9 μm to 18 μm.

(Surface treatment layer)
It is preferable that a surface treatment layer of at least one layer selected from a roughening treatment layer, a rust prevention layer, a heat resistance layer, and a silane coupling treatment layer is formed on the surface of the copper foil base material. The surface treatment layer of the present invention may thus be formed on the adhesive surface (M surface) with the resin, or may be formed on the surface opposite to the adhesive surface (M surface) (S surface). It may be formed on both sides.
The roughening treatment can be performed, for example, by forming roughened particles with copper or a copper alloy. The roughening process may be fine. Moreover, you may perform a covering plating process after a roughening process. Surface treatment layers formed by these roughening treatment, rust prevention treatment, heat treatment, silane treatment, immersion treatment in a treatment solution and plating treatment are Cu, Ni, Fe, Co, Zn, Cr, Mo, W, Any single substance selected from the group consisting of P, As, Ag, Sn, and Ge, or any one or more alloys or organic substances may be included.

  In order to suppress the influence of the ferromagnetic metal on the transmission characteristics, the total adhesion amount of Co, Ni and Fe in the surface treatment layer of the copper foil is controlled to a predetermined amount or less as described later, and as an alternative component By including Zn that does not exhibit ferromagnetism at room temperature, high-frequency transmission loss can be further reduced. For this reason, the surface treatment layer has a Zn metal layer or an alloy treatment layer containing Zn. Further, the alloy treatment layer containing Zn may be a Cu—Zn alloy layer. By setting it as a Cu-Zn alloy layer, heat resistance and chemical resistance can be improved rather than setting it as the metal layer of Zn single.

  When the surface treatment layer is formed using any of a roughening treatment layer, a rust prevention layer, a heat-resistant layer, and a silane coupling treatment layer, their order is not particularly limited. For example, the roughening treatment layer is formed on the copper foil surface. And a Zn metal layer or an alloy treatment layer containing Zn may be provided as a rust-proof and heat-resistant layer on the roughening treatment layer. Further, a chromate treatment layer may be provided on the Zn metal layer or the alloy treatment layer containing Zn. Furthermore, a silane coupling treatment layer may be provided on the chromate treatment layer.

(Metal adhesion amount)
In the surface-treated copper foil of the present invention, the total adhesion amount of Co, Ni, and Fe is controlled to 1000 μg / dm ² or less in the surface treatment layer. Thus, the surface-treated copper foil of the present invention has a high-frequency transmission loss because the amount of Co, Ni, and Fe having a relatively high permeability and a relatively low conductivity is controlled, which causes transmission loss. Can be reduced. The total adhesion amount of Co, Ni, and Fe in the surface treatment layer is preferably 500 μg / dm ² or less, more preferably 300 μg / dm ² or less, and even more preferably 0 μg / dm ² (lower limit of quantification of analysis). The following is shown).

When the surface treatment layer includes a roughening treatment layer, the adhesion amount of Cu in the roughening treatment layer is preferably 0.10 g / dm ² or less. According to such a configuration, high-frequency transmission loss can be further reduced. The adhesion amount of Cu in the roughened layer is more preferably 0.09 g / dm ² or less, still more preferably 0.08 g / dm ² or less, typically 0.04 to 0.08 g. / Dm ² .

The amount of Zn deposited on the surface treatment layer is preferably 5 mg / dm ² or less. According to such a configuration, chemical resistance is improved and heat resistance is improved. The adhesion amount of Zn in the surface treatment layer is more preferably 4.5 mg / dm ² or less, still more preferably 4 mg / dm ² or less, typically 0.1 to 4.5 mg / dm ² . is there.

The total adhesion amount of Cu, Zn, Co, Ni, and Fe in the surface treatment layer is preferably 0.10 g / dm ² or less. According to such a configuration, high-frequency transmission loss can be further reduced. The total adhesion amount of Cu, Zn, Co, Ni, and Fe in the surface treatment layer is more preferably 0.09 g / dm ² or less, further preferably 0.08 g / dm ² or less, typically 0.04 to 0.08 g / dm ² .

(Surface roughness Rz)
The roughness of the copper foil surface is a main factor of the conductor loss, and the transmission loss decreases as the roughness decreases. From such a viewpoint, the surface-treated copper foil of the present invention has a surface roughness Rz JIS of at least one surface controlled to 2.2 μm or less, and can reduce transmission loss satisfactorily. Moreover, it is preferable that surface roughness RzJIS of both surfaces is 2.2 micrometers or less. According to such a configuration, high-frequency transmission loss can be further reduced.
The surface roughness Rz JIS is more preferably 1.5 μm or less, still more preferably 1.2 μm or less, and typically 0.5 to 2.2 μm.

(Surface area ratio)
In addition to the surface roughness Rz managed by conventional high-frequency copper foil, the ratio of the three-dimensional surface area to the two-dimensional surface area more accurately represents the contact area with the resin (dielectric) that affects high-frequency transmission loss. It is necessary to control to an appropriate range. From such a viewpoint, in the surface-treated copper foil of the present invention, the ratio of the three-dimensional surface area to the two-dimensional surface area measured by the laser microscope on the surface of the surface-treated layer is controlled to 1.0 to 1.9, and the high-frequency Even if it is used for a circuit board, transmission loss can be further suppressed. If the surface area ratio is less than 1.0, it cannot be defined, and if it exceeds 1.9, there is a possibility that a high-frequency transmission loss increases. The surface area ratio is preferably 1.0 to 1.9, more preferably 1.0 to 1.6, and even more preferably 1.3 to 1.6.

(Method for producing surface-treated copper foil)
In the present invention, one surface or both surfaces of a copper foil base material (rolled copper foil or electrolytic copper foil) is subjected to a roughening treatment for performing fist-like electrodeposition on the surface of the copper foil after pickling. It is preferable. By roughening treatment, adhesion (peeling strength) with the resin (dielectric) is obtained. In the present invention, the roughening treatment is performed by, for example, any single element selected from the group consisting of Cu, Ni, Fe, Co, Zn, Cr, Mo, W, P, As, Ag, Sn, and Ge. It can be performed by plating one or more alloys, or surface treatment with an organic substance. Ordinary copper plating or the like may be performed as a pretreatment before roughening, and after the roughening, the plating may be performed with the above metal to impart heat resistance and chemical resistance. It should be noted that any single element or any one selected from the group consisting of Cu, Ni, Fe, Co, Zn, Cr, Mo, W, P, As, Ag, Sn, and Ge without roughening treatment. The above alloy may be plated. Then, as surface treatment, in order to give heat resistance and chemical resistance, it may cover and coat with the said metal. When the roughening treatment is performed, there is an advantage that the adhesion strength with the resin is increased. In addition, when the roughening treatment is not performed, the manufacturing process of the surface-treated copper foil is simplified, so that the productivity is improved, the cost can be reduced, and the roughness can be reduced. There are advantages. The content of treatment may be somewhat different between the rolled copper foil and the electrolytic copper foil. By adjusting the liquid composition, plating time, and current density of the plating treatment on the surface of such copper foil, the total adhesion amount of Co, Ni, and Fe in the surface treatment layer according to the present invention is controlled, and Zn in the surface treatment layer is controlled. A metal layer or an alloy-treated layer containing Zn can be formed, the ratio of the three-dimensional surface area to the two-dimensional surface area measured with a laser microscope on the surface of the surface-treated layer can be controlled, and the surface roughness Rz JIS can be controlled.

Moreover, the electrolytic copper foil whose surface roughness Rz is in the above-described range can be produced by the following method.
<Electrolyte composition>
Copper: 90-110 g / L
Sulfuric acid: 90-110 g / L
Chlorine: 50-100ppm
Leveling agent 1 (bis (3sulfopropyl) disulfide): 10 to 30 ppm
Leveling agent 2 (amine compound): 10 to 30 ppm
As the amine compound, an amine compound having the following chemical formula can be used.

(In the above chemical formula, R ₁ and R ₂ are selected from the group consisting of a hydroxyalkyl group, an ether group, an aryl group, an aromatic substituted alkyl group, an unsaturated hydrocarbon group, and an alkyl group.)

<Production conditions>
Current density: 70 to 100 A / dm ²
Electrolyte temperature: 50-60 ° C
Electrolyte linear velocity: 3-5 m / sec
Electrolysis time: 0.5 to 10 minutes

  The surface-treated copper foil of the present invention can be bonded to a resin substrate from the surface-treated layer side to produce a laminate. The resin substrate is not particularly limited as long as it has characteristics applicable to a printed wiring board, a printed circuit board, etc. For example, a paper base phenolic resin, a paper base epoxy resin, a synthetic fiber cloth for rigid PWB Substrate epoxy resin, fluororesin impregnated cloth, glass cloth / paper composite base epoxy resin, glass cloth / glass nonwoven fabric composite base epoxy resin, glass cloth base epoxy resin, etc., for flexible printed circuit boards (FPC) Polyester film, polyimide film, liquid crystal polymer (LCP) film, fluororesin and fluororesin / polyimide composite material can be used. Since liquid crystal polymer (LCP) has a small dielectric loss, it is preferable to use a liquid crystal polymer (LCP) film for a printed wiring board or a printed circuit board for high frequency circuits.

  In the case of the rigid PWB, a prepreg is prepared by impregnating a base material such as a glass cloth with a resin and curing the resin to a semi-cured state. It can be performed by stacking a copper foil on a prepreg and heating and pressing. In the case of FPC, a liquid crystal polymer or a polyimide film is bonded to a copper foil under high temperature and pressure without using an adhesive, or a polyimide precursor is applied and dried via an adhesive. -A laminated board can be manufactured by performing hardening etc.

  The laminate of the present invention can be used for various printed wiring boards (PWB) and printed circuit boards, and is not particularly limited. As a printed wiring board, for example, it can be applied to single-sided PWB, double-sided PWB, and multilayer PWB (three or more layers) from the viewpoint of the number of layers of the conductor pattern, and rigid PWB and flexible PWB from the viewpoint of the type of insulating substrate material. (FPC) and rigid flex PWB.

As copper foil base materials of Examples 1 to 10 and Comparative Examples 1 to 6, a rolled copper foil having a thickness of 18 μm (C1100 made by JX Nippon Mining & Metals) or an electrolytic copper foil having a thickness of 18 μm was prepared.
Next, plating was performed under the conditions shown in Tables 1 and 2 as the surface treatment. In Examples 1 to 4, surface treatment was performed on the deposition surface (Rz 0.6 μm) of the electrolytic copper foil produced by the above-described method, and Examples 5 to 7 and Comparative Examples 1 and 4 to 6 were drum surfaces of the electrolytic copper foil ( Rz 1.5 μm) was surface treated. In Comparative Examples 2 and 3, surface treatment was performed on the deposition surface (Rz 2.0 μm) of the electrolytic copper foil manufactured with the electrolytic solution containing no leveling agent. In Examples 8 to 10, surface treatment was performed on a rolled copper foil controlled to have a predetermined surface roughness. Table 1 shows the solution composition, pH, temperature, and current density of each of the plating solutions 1-10. Table 2 shows that the plating processes 1 to 3 were sequentially performed with the indicated bath composition and time. In addition, after this plating, heat resistance was ensured by Zn, Ni or their alloy plating, and chromate treatment, and further peel strength was improved by applying a silane coupling agent.
The application conditions of the silane coupling agent are as follows.
・ 3-Methacryloxypropyltrimethoxysilane ・ Silane concentration: 0.6 vol% (remainder: water)
-Processing temperature: 30-40 ° C
Treatment time: 5 seconds Drying after silane treatment: 100 ° C. × 3 seconds The surface treatment of Examples 1 and 9 corresponds to smooth plating treatment (surface treatment not roughening treatment), and other examples and The surface treatment in the comparative example corresponds to a roughening treatment.

  Various evaluation was performed as follows about each sample of the Example and comparative example which were produced as mentioned above.

<Measurement of adhesion amount>
For the measurement of the adhesion amount of various metals other than Cu in the surface treatment layer, the film on the surface of the copper foil of 50 mm × 50 mm was dissolved in a solution in which HNO ₃ (2 wt%) and HCl (5 wt%) were mixed. The metal concentration in the solution was quantified with an ICP emission spectroscopic analyzer (manufactured by SII NanoTechnology Inc., SFC-3100), and the amount of metal per unit area (μg / dm ² ) was calculated and derived. At this time, the analysis was performed by masking as necessary so that the metal adhesion amount on the surface opposite to the surface to be measured was not mixed. In addition, the measurement was performed about the sample after performing the above-mentioned Zn, Co, Ni, Fe or those alloy plating, chromate treatment, and also silane coupling treatment. Regarding the measurement of the adhesion amount of Cu on the surface treatment layer, from the weight of the surface-treated copper foil having a size of 100 mm × 100 mm, the adhesion amount of various metals other than Cu per area measured by the above method and the copper foil before surface treatment The weight per area was subtracted.

<Measurement of surface roughness Rz>
Using a contact roughness meter SP-11 manufactured by Kosaka Laboratory, the 10-point average roughness was measured for the surface-treated surface in accordance with JIS B0601-1994. The measurement position was changed 10 times under the conditions of a measurement standard length of 0.8 mm, an evaluation length of 4 mm, a cut-off value of 0.25 mm, and a feed rate of 0.1 mm / second, and values obtained by 10 measurements were obtained. . Moreover, about each electrolytic copper foil and rolled copper foil used by the Example and the comparative example, it measured beforehand about the roughness Rz before surface treatment.

<Measurement of surface area ratio>
The three-dimensional surface area was measured for a region having a two-dimensional surface area of 66455 μm ^{2 on} the precipitation surface of the surface-treated copper foil, using a laser microscope LEXT OLS4000 (laser wavelength 405 nm, differential interference method) manufactured by Olympus Corporation. A value obtained by dividing the measured three-dimensional surface area by the two-dimensional surface area was defined as a surface area ratio.

<Measurement of transmission loss>
For each sample with a thickness of 18 μm, after bonding with a commercially available liquid crystal polymer resin (Vecstar CTZ-50 μm manufactured by Kuraray Co., Ltd.), a microstrip line is formed by etching so that the characteristic impedance becomes 50Ω, and a network made by HP The transmission coefficient was measured using an analyzer HP8720C, and the transmission loss at a frequency of 20 GHz was determined. As an evaluation of transmission loss at a frequency of 20 GHz, 未 満 is less than 5.0 dB / 10 cm, ◯ is 5.0 dB / 10 cm or more and less than 6.0 dB / 10 cm, and x is 6.0 dB / 10 cm or more. Since the magnitude of the transmission loss depends on the relative dielectric constant, dielectric loss tangent, and thickness of the resin used, it is prominent with respect to the copper foil used in the general printed wiring board (copper foil used in Comparative Example 2). The above criteria were used because of the transmission loss reduction effect.
The test results are shown in Table 3.

(Evaluation results)
In each of Examples 1 to 10, the total adhesion amount of Co, Ni, and Fe in the surface treatment layer is 1000 μg / dm ² or less, the surface treatment layer has a Zn metal layer or an alloy treatment layer containing Zn, The surface area ratio was 1.0 to 1.9, and the surface roughness Rz JIS was 2.2 μm or less. For this reason, in all of Examples 1 to 10, the transmission loss was satisfactorily suppressed.
Comparative Example 1 had a large transmission loss because the surface area ratio exceeded 1.9.
In Comparative Example 2, since the surface roughness Rz JIS exceeded 2.2 μm and the surface area ratio exceeded 1.9, the transmission loss was large.
In Comparative Example 3, since the surface roughness Rz JIS exceeded 2.2 μm, the transmission loss was large.
In Comparative Examples 4 to 6, the plating treatment 3 of Example 7 was changed to one containing Co, Ni, and Fe, and the total adhesion amount of Co, Ni, and Fe in the surface treatment layer exceeded 1000 μg / dm ² . Therefore, the transmission loss was larger than that in Example 7.
In FIG. 1, the graph which shows the relationship between the total adhesion amount of Co, Ni, and Fe which concerns on an Example and a comparative example, and surface roughness Rz is shown. In FIG. 2, the graph which shows the relationship between the total adhesion amount of Co, Ni, and Fe which concerns on an Example and a comparative example, and the ratio of the three-dimensional surface area with respect to a two-dimensional surface area is shown. In FIG. 3, the graph which shows the relationship between the total adhesion amount of Co, Ni, Fe, Cu, and Zn which concerns on an Example and a comparative example, and transmission loss is shown.

Claims (19)

A surface-treated copper foil having a surface-treated layer formed on at least one surface,
The surface treatment layer includes a roughening treatment layer,
The total adhesion amount of Co, Ni, and Fe in the surface treatment layer is 300 μg / dm ² or less, the surface treatment layer has a Zn metal layer or an alloy treatment layer containing Zn, and a laser microscope on the surface of the surface treatment layer The ratio of the three-dimensional surface area to the two-dimensional surface area measured at 1.0 to 1.9,
The surface-treated copper foil whose surface roughness Rz JIS of at least one surface is 2.2 micrometers or less. The surface-treated copper foil according to claim 1, wherein a total adhesion amount of Co, Ni, and Fe in the surface treatment layer is 0 μg / dm ² .   The surface-treated copper foil according to claim 1 or 2, wherein the surface-treated layers are formed on both surfaces, and the surface roughness Rz JIS of the both surfaces is 2.2 µm or less. A surface-treated copper foil having a surface-treated layer formed on at least one surface,
The total adhesion amount of Co, Ni, and Fe in the surface treatment layer is 986 μg / dm ² or less, the surface treatment layer has a Zn metal layer or an alloy treatment layer containing Zn, and a laser microscope on the surface of the surface treatment layer The ratio of the three-dimensional surface area to the two-dimensional surface area measured at 1.0 to 1.9,
The surface-treated copper foil whose surface roughness Rz JIS of at least one surface is 0.6 micrometer or less.   The surface-treated copper foil of Claim 4 in which the said surface treatment layer contains a roughening process layer.   The surface-treated copper foil according to claim 4 or 5, wherein the surface-treated layers are formed on both surfaces, and the surface roughness Rz JIS of the both surfaces is 0.6 µm or less. The surface-treated copper foil as described in any one of Claims 1-3, 5 and 6 whose adhesion amount of Cu in the said roughening process layer is 0.10 g / dm < ² > or less.   In the said surface treatment layer, the surface treatment copper foil as described in any one of Claims 1-3 and 5-7 in which the alloy treatment layer containing the said Zn metal layer or Zn is provided on the said roughening treatment layer. .   The surface-treated copper foil according to any one of claims 1 to 8, wherein the alloy-treated layer containing Zn is a Cu-Zn alloy layer. The surface-treated copper foil as described in any one of Claims 1-9 whose adhesion amount of Zn in the said surface treatment layer is 5 mg / dm < ² > or less.   The surface-treated copper foil as described in any one of Claims 1-10 in which the chromate treatment layer is provided on the alloy treatment layer containing the said Zn metal layer or Zn in the said surface treatment layer.   The surface-treated copper foil according to claim 11, wherein a silane coupling treatment layer is provided on the chromate treatment layer. The surface treatment copper foil as described in any one of Claims 1-12 whose total adhesion amount of Cu, Zn, Co, Ni, and Fe in the said surface treatment layer is 0.10 g / dm < ² > or less.   It is an object for flexible printed wiring boards, The surface-treated copper foil as described in any one of Claims 1-13.   The surface-treated copper foil according to any one of claims 1 to 13, which is for a high-frequency circuit board of 5 GHz or more.   The laminated board comprised by laminating | stacking the surface treatment copper foil and resin substrate as described in any one of Claims 1-13.   A printed wiring board made of the laminated board according to claim 16.   A printed circuit board made of the laminate according to claim 16.   An electronic device using the printed circuit board according to claim 18.