TWI536878B - Surface treatment of copper foil and laminated board - Google Patents

Description

Surface treated copper foil and laminate

The present invention relates to surface treated copper foil and laminates.

Conventionally, a flexible printed circuit board (FPC) used as a circuit board of an electronic device such as a mobile phone has, for example, a copper foil and a polyimide film provided on at least one main surface of the copper foil. A laminate of a resin substrate is formed. A copper foil of a predetermined portion is removed by etching or the like on the laminate to form a circuit pattern (copper wiring). When an electronic component or the like is mounted on the FPC, the positioning mark is confirmed by the resin substrate (the resin substrate that has passed through the portion where the copper foil is removed) through the portion where the copper foil is removed, and the mounting position of the electronic component or the like is positioned. Therefore, the FPC is required to have high transparency (hereinafter, simply referred to as "transparency of the resin substrate") of the resin substrate after the copper foil is attached and removed. Therefore, it has been proposed to adjust the surface roughness of the copper foil so that the light transmittance of the resin substrate becomes 30%, or to set the light transmittance of the resin substrate to 40% or more and the haze value (haze value) of the resin substrate. The method of adjusting the surface roughness of the copper foil in a manner of 30% or less (see, for example, Patent Documents 1 to 3).

[Prior Art Literature]

[Patent Literature]

Patent Document 1: Japanese Patent Laid-Open Publication No. 2013-147688

Patent Document 2: Japanese Patent No. 5035220

Patent Document 3: Japanese Laid-Open Patent Publication No. 2004-98659

However, when an electronic component or the like is mounted on the FPC, the resin substrate and the positioning mark are not adhered to each other, but are separated by a predetermined distance. Therefore, even if the light transmittance of the resin substrate or the haze value of the resin substrate is adjusted, when the electronic component or the like is mounted on the FPC, the positioning mark may not be confirmed through the resin substrate or the positioning mark may be difficult to be confirmed. As a result, the installation workability is lowered.

An object of the present invention is to provide a technique for improving the mounting workability when mounting an electronic component or the like on a flexible printed circuit board.

According to an aspect of the present invention, a surface-treated copper foil comprising: a copper foil substrate; a copper plating layer formed on the copper foil substrate; and a roughened copper plating layer formed on the copper plating layer The surface-treated copper foil is formed on the two main faces of the resin substrate such that the surface of the surface-treated copper foil opposite to the surface on which the roughened copper plating layer is provided is in contact with the resin substrate. When the surface-treated copper foil is bonded to the two main surfaces of the resin substrate, the resin substrate has a haze value of 80% or less and a transparency of 70% or more. The peeling strength between the surface-treated copper foil and the resin substrate was 0.6 N/mm or more.

According to another aspect of the present invention, there is provided a laminate comprising: a surface-treated copper foil having a copper foil substrate, a copper plating layer formed on the copper foil substrate, and a copper plating layer formed on the copper plating layer a roughened copper plating layer; and a resin substrate formed in contact with a surface on a side where the roughened copper plating layer is provided, the surface treated copper foil being formed in such a manner that two main faces of the resin substrate are When the surface-treated copper foil is bonded to the surface-treated copper foil, and the surface-treated copper foil is removed from the two main surfaces of the resin substrate, the haze value of the resin substrate is 80%. Hereinafter, the transparency is 70% or more, and the peel strength between the surface-treated copper foil and the resin substrate is 0.6 N/mm or more.

According to the present invention, it is possible to improve the workability in mounting an electronic component or the like on a flexible printed circuit board.

1‧‧‧Surface treated copper foil

2‧‧‧copper substrate

3‧‧‧ copper plating

4‧‧‧Rough copper plating

5‧‧‧Anti-rust layer

10‧‧‧Laminated boards

11‧‧‧Resin substrate

20‧‧‧Measurement device

21‧‧·score ball

21a‧‧‧Light inlet

21b‧‧‧Light discharge

22‧‧‧Light source

23‧‧‧Detector

24‧‧‧ cover

25‧‧‧Resin substrate

30‧‧‧Measurement device

31‧‧‧ Sensor

31a‧‧‧Center Sensor

31b‧‧‧Ring Sensor

100‧‧‧FPC

101‧‧‧Light source

102‧‧‧CCD camera

103‧‧‧ Positioning Mark

1 is a schematic cross-sectional view of a laminate having a surface-treated copper foil according to an embodiment of the present invention; and FIG. 2 is a schematic view showing a device for measuring a haze value of a resin substrate; and FIG. 3(a) is a view showing FIG. 3(b) is a schematic plan view of a sensor used in the device shown in FIG. 3(a); FIG. 4 is a schematic view showing an embodiment of the present invention. A flowchart of a manufacturing process of the surface-treated copper foil and the laminated board; and FIG. 5 is a schematic view showing a state in which an electronic component or the like is mounted on a flexible printed circuit board formed of a laminated board according to an embodiment of the present invention.

(information obtained by the inventor, etc.)

First, the findings obtained by the inventors and the like will be described before explaining the embodiments of the present invention. A circuit board such as FPC uses a laminate (copper laminate) having a surface-treated copper foil and a resin substrate, wherein the surface-treated copper foil has a copper foil substrate and roughness provided on any main surface of the copper foil substrate Copper plating. The laminated plate is formed such that the surface of the surface-treated copper foil on which the roughened copper plating layer is provided is bonded to the resin substrate. For example, as shown in FIG. 5, when the electronic component or the like is mounted on the FPC 100, the mounting position of the electronic component or the like is performed by irradiating the light with the light source 101 and removing the light to form a copper wiring, for example, using a CCD camera 102 or the like. The resin substrate at the portion where the copper foil was surface-treated was used to confirm the positioning mark 103 at the mounting position. Therefore, the resin substrate from which the surface of the copper foil is removed is required to have high transparency. However, if the resin substrate and the surface-treated copper foil are formed when the laminate is formed When the bonding is performed, the unevenness formed on the surface of the surface-treated copper foil is transferred to the resin substrate by roughening the copper plating layer, and thus the transparency of the resin substrate is lowered. Then, in order to attach and remove the surface-treated copper foil, the haze value and light transmittance of the resin substrate (hereinafter, these are also referred to as "haze value of resin substrate" and "light of resin substrate" The surface roughness of the surface on the side where the surface-treated copper foil is bonded to the resin substrate is adjusted so that the transmittance ") is a predetermined value. The haze value of the resin substrate is a ratio of the amount of diffused transmitted light (the amount of light that is not linearly propagated and diffused) to the amount of total light transmitted through the resin substrate. The light transmittance of the resin substrate is a value measured by parallel rays regardless of reflection or scattering of light. When light is reflected and scattered, the light transmittance of the resin substrate is lowered. That is, the light transmittance of the resin substrate and the amount of linearly transmitted transmitted light (the amount of light that is not diffused and propagated linearly) are related to the ratio of the amount of total light transmitted through the resin substrate. However, since the light transmittance is different from the measuring device and the measuring method of the amount of straight-through transmitted light, the absolute value of the value of the absolute value of the light transmittance and the ratio of the straight-through transmitted light does not match. Thus, the haze value of the resin base material and the transmittance of the resin base material are each an index indicating the transparency (turbidity) of the resin base material itself, and are in a state of being dependent on each other. For example, when the haze value of the resin substrate is increased, the light transmittance value of the resin substrate is reduced, and when the haze value of the resin substrate is decreased, the light transmittance value of the resin substrate is increased.

When the electronic component or the like is mounted on the FPC 100, the resin substrate (FPC 100) is disposed at a position apart from the positioning mark 103 (see FIG. 5). That is, in the actual mounting step, the resin substrate and the positioning mark 103 are not in close contact. Therefore, in the actual mounting step, when light is irradiated from the light source 101 to the resin substrate, a part of the light that has passed through the resin substrate is scattered. As a result, even if the surface-treated copper foil is adjusted such that the haze value and the light transmittance of the resin substrate become a predetermined value, it is difficult to confirm the positioning mark 103 through the resin substrate in the actual mounting step, and the mounting work may be performed. Sex will decrease. In other words, it is not possible to improve the mounting workability by merely controlling the haze value and the light transmittance of the resin base material which is an index for evaluating the transparency of the resin substrate itself without considering the scattering of light transmitted through the resin substrate. The present invention has been completed based on the above findings discovered by the inventors.

<An embodiment of the present invention>

(1) Composition of surface treated copper foil and laminated board

First, the configuration of the surface-treated copper foil according to an embodiment of the present invention will be described with reference to Fig. 1 . Fig. 1 is a schematic cross-sectional view showing a laminated board 10 including the surface-treated copper foil 1 according to the present embodiment.

(surface treated copper foil)

As shown in Fig. 1, the surface-treated copper foil 1 according to the present embodiment includes a copper foil base material 2, a copper plating layer 3 formed on the copper foil base material 2, and roughening formed on the copper plating layer 3. Copper plating layer 4. Further, the surface-treated copper foil 1 is formed in such a manner that the surface of the copper-plated layer 4 is opposite and roughened on the two main faces of the polyimide film as a resin substrate, for example, the surface-treated copper foil 1 When the surface-treated copper foil 1 is bonded to the resin substrate from the resin substrate, the haze value of the resin substrate is 80% or less, and the transparency is 70% or more. The peel strength between the copper foil and the resin substrate was 0.6 N/mm or more.

The haze value (haze value) of the resin substrate is an index for evaluating the transparency (the turbidity of the appearance) of the appearance of the resin substrate. In other words, the haze value of the resin substrate is a ratio of the amount of diffused transmitted light of the resin substrate (the amount of diffused transmitted light) to the amount of total light transmitted through the resin substrate (the amount of total light transmitted). On the two main faces of the resin substrate, one side of the roughened copper plating layer 4 of the two surface-treated copper foils 1 is brought into contact with the resin substrate while the two surface-treated copper foils 1 are opposed to each other and bonded thereto. The surface-treated copper foil 1 is removed by, for example, etching, and the haze value of the resin substrate from which the surface-treated copper foil 1 is removed (hereinafter, simply referred to as "the resin substrate after etching") is measured, and it can be evaluated when When the resin substrate after the etching is in close contact with the positioning mark (identification mark, alignment mark), whether the positioning mark can be confirmed via the resin substrate after etching (permeation of the resin substrate after etching).

The measurement of the haze value is performed using, for example, the measuring device 20 shown in Fig. 2 . For example, the haze value is measured by a device including the integrating sphere 21, the light source 22, and the detector 23. The inner peripheral surface of the integrating sphere 21 is configured such that light emitted from the light source 22 and introduced into the integrating sphere 21 from the light introducing port 21a is uniformly diffused (reflected). In the integrating sphere 21, the light introduction port 21a that introduces light from the light source 22 and the light discharge port 21b that is provided at a position facing the light introduction port 21a to discharge light are passed through Set through the wall. A cover 24 that blocks the light discharge port 21b is provided in the light discharge port 21b. The surface of the lid body 24 located inside the integrating sphere 21 is configured to diffuse (reflect) the light introduced into the integrating sphere 21.

A light source 22 is disposed at a position outside the integrating sphere 21 and facing the light introducing port 21a. The light source 22 is disposed, for example, such that the optical axis of the light source 22 coincides with the center position of the light introduction port 21a. The light source 22 is preferably disposed such that the distance L between the light emission position and the center position of the light introduction port 21a coincides with the installation distance. However, the light source 22 may not be disposed in such a manner that the distance L and the mounting distance are the same. In addition, the mounting distance refers to the distance between the resin base material 11 and the light source 22 when an electronic component or the like is mounted on the laminated board 10 to be described later. The detector 23 is configured to measure the amount of light that is emitted from the light source 22 and introduced into the integrating sphere 21 from the light introduction port 21a.

The measurement of the haze value of the resin substrate was carried out as follows. First, the resin substrate 25 as a measurement object is placed in the light introduction port 21a. For example, the resin base material 25 is disposed so as to block the light introduction port 21a from the outside of the integrating sphere 21. Then, in a state where the light discharge port 21b is closed (closed) by the lid body 24, light is irradiated from the light source 22, and the amount of light transmitted through the resin substrate 25 and introduced into the integrating sphere 21 is measured by the detector 23 (the amount of total light transmitted light) ). Then, the light source 22 is irradiated with light while the cover 24 is opened and the light discharge port 21b is opened, and the amount of light that is transmitted through the resin substrate 25 and introduced into the integrating sphere 21 without being discharged from the light discharge port 21b is measured ( Diffused transmitted light amount). Then, the haze value of the resin base material 25 to be measured is calculated from the following (number 1).

(Number 1) Haze value (%) = (Diffuse transmitted light amount / Total light transmitted light amount) × 100

Transparency (CLARITY) is an index for evaluating the directivity of light transmitted through a resin substrate. In particular, transparency is an index for evaluating the directivity of light traveling straight through the resin substrate. That is to say, with respect to transparency, the transparency of the resin substrate was evaluated by detecting scattered light (small-angle scattered light) of light traveling straight through the resin substrate. By measuring the transparency of the resin substrate after etching, it can be evaluated that when the resin substrate after etching is disposed at a position apart from the positioning mark (that is, when the resin substrate after etching is not adhered to the positioning mark), Whether or not the positioning mark is confirmed through the resin substrate after etching.

For the measurement of transparency, for example, the measuring device shown in Fig. 3 (a) is used. 30 to carry out. The measuring device 30 shown in Fig. 3 is the same as the measuring device 20 for haze value shown in Fig. 2 except that the sensor 31 is provided in the light discharge port 21b. The sensor 31 of the measuring device 30 includes a disk-shaped center sensor 31a and an annular ring-shaped sensor 31b. As shown in FIG. 3(b), the ring-shaped sensor 31b is provided to surround the outer circumference of the center sensor 31a.

The transparency of the resin substrate was measured as follows. First, a resin substrate 25 as a measurement object is placed at a light emitting position of the light source 22. Then, the light is irradiated from the light source 22 without providing the lid body 24, and the light introduced into the integrating sphere 21 from the light introduction port 21a through the resin substrate 25 is received by the center sensor 31a and the ring sensor 31b, respectively. The transparency of the resin substrate 25 to be measured is calculated from the following (number 2) by the amount of light (IC) received by the center sensor 31a and the amount of light (IR) received by the ring sensor 31b.

(Number 2) Transparency (%) = {(IC-IR) / (IC + IR)} × 100

The peel strength is an index for evaluating the adhesion between the resin substrate and the surface-treated copper foil. The higher the peel strength, the higher the adhesion.

(copper foil substrate)

As described above, the surface-treated copper foil 1 according to the present embodiment includes the copper foil base material 2. As the copper foil base material 2, for example, a rolled copper foil or an electrolytic copper foil is used. As the copper foil base material 2, a rolled copper foil which is superior in bending resistance to an electrolytic copper foil and which is not easily broken even if it is repeatedly bent is preferably used. As a material for forming the rolled copper foil, for example, pure copper such as OFC (Oxygen-Free Copper) or tough copper (TPC: Tough-Pitch Copper) is used. The oxygen-free copper is a copper material having a purity of 99.96% or more as defined in JIS C1020 and JIS H3100. The oxygen-free copper may also contain, for example, oxygen at a level of several ppm. That is, the oxygen content of the oxygen-free copper may not be zero. The tough pitch copper is, for example, a copper material having a purity of 99.9% or more as defined in JIS C1100 or JIS H3100. The tough pitch copper may also contain oxygen, for example, in the range of 100 ppm to 600 ppm. As a material for forming the rolled copper foil, a low-concentration copper alloy in which a predetermined amount of a predetermined additive such as tin (Sn) or silver (Ag) is added to oxygen-free copper or tough pitch copper may be used. Thereby, heat resistance and the like of the rolled copper foil can be improved.

(copper plating)

On either main surface of the copper foil substrate 2, a copper plating layer 3 is formed, for example, by plating or the like. The copper plating layer 3 is a smooth copper plating layer functioning as a base layer of the roughened copper plating layer 4. The copper plating layer 3 contains a predetermined amount of sulfur element (S). That is, the copper plating layer 3 is formed using a copper plating liquid to which an organic compound (organic sulfur compound) having a mercapto group is added. Hereinafter, the copper plating liquid forming the copper plating layer 3 is simply referred to as "copper plating liquid". As the organic compound having a mercapto group, for example, bis(3-sulfopropyl) disulfide (SPS) is used.

The amount of the organic sulfur compound to be added is preferably, for example, 5 mg/L or more and 60 mg/L or less, more preferably 5 mg/L or more and 45 mg/L or less, and still more preferably 5 mg/L or more and 30 mg/L or less. When the amount of the organic sulfur compound added is less than 5 mg/L, the effect of improving the transparency of the resin substrate and suppressing the decrease in adhesion may not be sufficiently obtained. When the amount of the organic sulfur compound added is 5 mg/L or more, the problem can be solved, and the transparency of the resin substrate can be improved and the decrease in adhesion can be suppressed. That is, the transparency of the desired resin substrate and the desired adhesion can be obtained. However, if the amount of the organic sulfur compound added exceeds 60 mg/L, the solubility of the organic sulfur compound in the copper plating solution may be lowered, and the effect of adding the organic sulfur compound may not be sufficiently obtained. Since the organic sulfur compound is a high-priced raw material, if the amount added exceeds 60 mg/L, the production cost of the surface-treated copper foil becomes high. These problems can be eliminated by setting the amount of the organic sulfur compound to be 60 mg/L or less. In other words, it is possible to suppress a decrease in the solubility of the organic sulfur compound and to suppress an increase in the production cost. When the amount of the organic sulfur compound added is 45 mg/L, the decrease in the solubility of the organic sulfur compound can be further suppressed, and the increase in the production cost can be further suppressed. When the amount of the organic sulfur compound added is 30 mg/L, it is possible to further suppress the decrease in the solubility of the organic sulfur compound, and it is possible to further suppress an increase in the production cost.

Further, a surfactant, a leveling agent, a chloride ion or the like may be added to the copper plating solution.

As the surfactant, any of polyethylene glycol, polypropylene glycol, polyoxyalkylene ether, and the like is used. Specifically, as the surfactant, a chemical liquid containing any one of polyethylene glycol, polypropylene glycol, and polyoxyalkylene ether as a main component is used. As the surfactant, for example, a surfactant liquid of the CU-BRITE TH-R III (registered trademark) series manufactured by Ebara Co., Ltd. is used. The amount of surfactant added is, for example, It is preferably 1 ml/L or more and 4 ml/L or less.

As the leveling agent, diallyldialkylammonium alkyl sulfate or the like is used. Specifically, as the leveling agent, a chemical liquid containing a main component such as diallyldialkylammonium alkyl sulfate is used. In addition, as a leveling agent, for example, a leveling agent chemical liquid containing a polymer hydrocarbon as a main component such as CU-BRITE TH-R III series manufactured by 荏原优莱特株式会社 can be used. When the CU-BRITE TH-R III series as a leveling agent is used, the amount of the leveling agent added is preferably, for example, 3 ml/L or more and 10 ml/L or less.

As the chloride ion, for example, a chemical solution containing chloride ions (that is, hydrochloric acid or an aqueous solution of HCL) is used. The amount of hydrochloric acid added is preferably, for example, 0.05 ml/L or more and 0.3 ml/L or less.

The copper plating layer 3 is preferably formed so that the thickness thereof is, for example, 0.1 μm or more and 0.6 μm or less. Thereby, the haze value of the resin substrate after the etching can be made lower and the transparency can be made higher. That is, the transparency of the resin substrate after etching can be further improved. If the thickness of the copper plating layer 3 is less than 0.1 μm, the effect of providing the copper plating layer 3 cannot be obtained, and the transparency of the resin substrate after etching is lowered. If the thickness of the copper plating layer 3 exceeds 0.6 μm, in the case of using, for example, a rolled copper foil as the copper foil substrate 2, recrystallization of the copper foil substrate 2 may be hindered, sometimes resulting in the copper foil substrate 2 The bending resistance is lowered.

(roughened copper plating)

A roughened copper plating layer 4 is formed on the copper plating layer 3. Thereby, the anchoring effect can be obtained, and the adhesion between the surface-treated copper foil 1 and the resin base material 11 in the laminated board 10 mentioned later (it is also called only "adhesiveness". The roughened copper plating layer 4 is mainly composed of a plurality of roughened particles. It is preferable that the roughened copper plating layer 4 is in a state where no roughening is caused. For example, it is preferable to form the roughened copper plating layer 4 so as not to expose the copper plating layer 3 when the copper plating layer 4 is roughened as seen from the upper surface.

The roughened particles forming the roughened copper plating layer 4 are formed of, for example, copper (Cu) (i.e., elemental Cu). As the roughened particles, for example, at least one metal element containing Cu and iron (Fe), molybdenum (Mo), nickel (Ni), cobalt (Co), chromium (Cr), zinc (Zn) or tungsten (W) may be used. The plating solution is formed.

The roughened copper plating layer 4 has an average thickness of 0.05 μm or more and 0.30 μm. The following methods are formed as preferred. The average thickness of the roughened copper plating layer 4 is the thickness when the roughened copper plating layer 4 is uniformly flattened. Thereby, it is possible to improve the transparency of the resin substrate while maintaining the adhesion. If the average thickness of the roughened copper plating layer 4 is less than 0.05 μm, the anchoring effect by the provision of the roughened copper plating layer 4 cannot be obtained, and the adhesion is lowered. When the average thickness of the roughened copper plating layer 4 exceeds 0.30 μm, when the laminated board 10 described later is formed, the size of the unevenness transferred to the resin substrate 11 becomes large (for example, the depth of the concave portion becomes deep), and the resin substrate is formed. The transparency will be reduced.

(rustproof layer)

It is preferable to form a rust-preventing layer (post-treatment plating layer) 5 having a predetermined thickness (for example, 1 nm or more and 70 nm or less) on the roughened copper plating layer 4. The rustproof layer 5 is formed using a predetermined plating solution. Thereby, heat resistance, chemical resistance, and the like of the surface-treated copper foil 1 can be improved. Further, when the laminated board 10 is formed and the predetermined portion of the surface-treated copper foil 1 is removed by etching to form a copper wiring, the surface-treated copper foil 1 can be easily removed.

The rust-preventing layer 5 has, for example, a nickel-plated (Ni) layer having a thickness of 10 nm or more and 50 nm or less, a galvanized (Zn) layer having a thickness of 1 nm or more and 10 nm or less, and a thickness of 1 nm or more, in this order from the side of the copper foil base material 2 . A chromate treatment layer of 10 nm or less (trivalent chromium formation layer) and a very thin (very thin) decane coupling layer are preferred. When the Ni plating layer is provided, when the laminated plate 10 is formed, it is possible to suppress the diffusion of Cu of the surface-treated copper foil 1 toward the resin substrate side, and it is possible to improve the heat resistance and chemical resistance of the surface-treated copper foil 1. The Zn plating layer has a function as a base layer for providing a chromate treatment layer and a decane coupling layer. Further, if a Zn plating layer is provided, the heat resistance of the surface-treated copper foil 1 can be further improved. Each of the chromate-treated layer and the decane-coupled layer also functions as a chemical conversion treatment layer (chemical conversion treatment film). When the decane coupling layer is provided, the chemical adhesion between the surface-treated copper foil 1 and the resin substrate 11 to be described later can be improved, and the adhesion can be further improved.

(Laminated board)

In the laminated board (CCL: Copper Clad Laminate) 10 according to the present embodiment, the surface of the surface-treated copper foil 1 on which the roughened copper plating layer 4 is provided is bonded to the resin substrate 11 form. The laminate 10 can also be formed using, for example, two surface-treated copper foils 1. That is to say, the laminate 10 can also By contacting the resin substrate 11 on the side of the two surface-treated copper foils 1 provided with the roughened copper plating layer 4 on both main faces (both sides) of the resin substrate 11 and making two The surface-treated copper foil 1 is formed by being bonded to each other. As the resin substrate 11, for example, a polyester film such as a polyimide film (PI) resin film or polyethylene terephthalate (PET), a liquid crystal polymer (LCP), or the like is used.

(2) Method for producing surface-treated copper foil and laminated board

Next, a method of manufacturing the surface-treated copper foil 1 and the laminated board 10 according to the present embodiment and a flexible printed circuit board (FPC) formed by the laminated board 10 will be described with reference to FIG. Fig. 4 is a flow chart showing the steps of manufacturing the surface-treated copper foil 1 and the laminated plate 10 according to the present embodiment.

[Surface Treatment Copper Foil Forming Step (S10)]

First, a method of manufacturing the surface-treated copper foil 1 according to the present embodiment will be described.

(copper foil substrate forming step (S11))

For example, a rolled copper foil or an electrolytic copper foil as the copper foil base material 2 is formed. When the rolled copper foil is used as the copper foil base material 2, for example, first, an ingot of pure copper composed of oxygen-free copper and tough pitch copper is cast; and oxygen-free copper and tough pitch copper are used as a mother phase, and the mother phase is added. An ingot of a low-concentration copper alloy having a predetermined amount of an additive such as Sn or Ag. Then, the cast ingot is subjected to a predetermined hot rolling treatment, a predetermined cold rolling treatment, a predetermined annealing treatment, or the like to form a rolled copper foil having a predetermined thickness (for example, 11 μm). At this time, it is preferable to adjust the heat resistance of the rolled copper foil in accordance with the heating temperature at the time of recrystallization of the rolled copper foil.

(copper plating layer forming step (S12))

After the completion of the copper foil substrate forming step (S11), first, the surface of the copper foil substrate 2 is cleaned. Then, a copper plating treatment for forming the copper plating layer 3 is performed on any of the main surfaces of the copper foil substrate 2.

<Cleaning treatment (S121)>

After the completion of the copper foil substrate forming step (S11), the surface of the copper foil substrate 2 is cleaned. For example, the surface of the copper foil substrate 2 is subjected to electrolytic degreasing treatment and pickling treatment as a cleaning treatment. As the electrolytic degreasing treatment, for example, a cathodic electrolytic degreasing treatment using an alkali solution such as sodium hydroxide is performed. As an alkali solution, for example, There are 20 g/L or more of 60 g/L or less of sodium hydroxide, and an aqueous solution containing 10 g/L or more and 30 g/L or less of sodium carbonate. For the pickling treatment, for example, the copper foil base material 2 is immersed in an acidic aqueous solution such as sulfuric acid to neutralize the alkali component remaining on the surface of the copper foil base material 2 or to remove the copper oxide film. As the acidic aqueous solution, an aqueous solution containing 120 g/L or more and 180 g/L or less of sulfuric acid, an aqueous solution containing citric acid or the like, a copper etching solution for etching copper, or the like is used.

<Copper plating treatment (S122)>

After the cleaning process (S121) is completed, a copper plating solution is prepared. As the copper plating solution, for example, an aqueous solution (acidic copper plating bath) containing copper sulfate and sulfuric acid as a main component is prepared. Then, a predetermined amount (for example, 5 mg/L or more and 60 mg/L or less) of SPS is added as an organic sulfur compound to the copper plating solution. Further, a surfactant, a leveling agent, or a chloride ion may be added to the copper plating solution as needed. A surfactant solution of a CU-BRITE TH-R III series, which is a predetermined amount (for example, 1 ml/L or more and 4 ml/L or less), may be added to the copper plating solution as a surfactant. In addition, a CU-BRITE TH-R III series leveling agent liquid liquid of a CU-BRITE TH-R III series, which is a predetermined amount (for example, 3 ml/L or more and 10 ml/L or less) may be added to the copper plating liquid as a leveling agent. . Further, a predetermined amount (for example, 0.05 ml/L or more and 0.3 ml/L or less) of hydrochloric acid may be added as a chloride ion to the copper plating solution.

Then, as a copper plating treatment, a plating treatment is performed in a copper plating solution to form a copper plating layer 3 having a predetermined thickness (for example, 0.1 μm or more and 0.6 μm or less) on one main surface of the copper foil base material 2. The current density at the time of forming the copper plating layer 3 is a density smaller than the limiting current density in the plating conditions. That is, it is assumed that the current density of the metal particles is not precipitated in the copper plating liquid (the so-called "scorch plating layer" is not formed). Thereby, a smooth copper plating layer can be formed as the copper plating layer 3. On the other hand, the larger the current density, the more the productivity can be improved. Therefore, it is preferable that the current density is as high as possible within a range smaller than the limit current density.

In the copper plating treatment (S122), the treatment conditions such as the liquid composition, liquid temperature, current density, and treatment time (plating time) of the copper plating solution can be set, for example, as shown in Table 1 below. At this time, it is preferable to use the Cu plate as the anode and the copper foil base material 2 itself to be subjected to the copper plating treatment (S122) as the cathode.

The addition amount of the copper sulfate pentahydrate in the copper plating solution is preferably 50 g/L or more and 300 g/L or less, and the amount of sulfuric acid added is preferably 30 g/L or more and 200 g/L or less. As shown in Table 1, the thickness of the copper plating layer 3 can be made 0.1 μm or more and 0.6 μm or less by setting the treatment time to 1 second or longer and 30 seconds or shorter.

(roughening copper plating layer forming step (S13))

After the copper plating layer forming step (S12) is completed, the copper foil substrate 2 on which the copper plating layer 3 is formed is washed with water, and then roughened copper plating having a predetermined thickness (for example, 0.05 μm or more and 0.3 μm or less) is formed on the copper plating layer 3. Layer 4. That is, the plating solution (roughening copper plating liquid) forming the roughened copper plating layer 4 is subjected to a plating treatment to form a roughened copper plating layer 4. As the roughened copper plating solution, for example, an acid copper plating bath containing copper sulfate and sulfuric acid as a main component is used. Further, it is preferred to add, for example, an aqueous solution containing a predetermined amount (for example, 10 g/L or more and 30 g/L or less) of iron sulfate heptahydrate to the roughened copper plating solution.

The current density at the time of forming the roughened copper plating layer 4 is set to be equal to or higher than the limiting current density in the plating conditions. In other words, it is assumed that the metal particles can be precipitated in the roughened copper plating solution, and the roughened particles adhere to the copper plating layer 3 (becomes a so-called "scorched plating layer").

In the roughening copper plating layer forming step (S13), the plating treatment conditions such as the liquid composition, liquid temperature, current density, and treatment time of the roughened copper plating solution can be set, for example, as shown in Table 2 below. At this time, a Cu plate as a cathode was used, and the copper foil base material 2 itself subjected to the roughening copper plating treatment was used as a cathode.

As shown in Table 2, the average thickness of the roughened copper plating layer 4 can be made 0.05 μm or more and 0.3 μm or less by setting the treatment time to 0.3 seconds or more and 2.5 seconds or less.

(rustproof layer forming step (S14))

After the roughening copper plating layer forming step (S13) is completed, the copper foil base material 2 on which the roughened copper plating layer 4 is formed is washed with water, and then a predetermined thickness (for example, 1 nm or more and 70 nm or less) is formed on the roughened copper plating layer 4. Anti-rust layer 5. That is, the plating treatment is performed in the plating solution forming the rustproof layer 5 to form the rustproof layer 5. The thickness of the rustproof layer 5 has a certain relationship with the amount of plating. That is to say, the amount of plating increases, and the thickness of the rustproof layer 5 becomes thick. Therefore, it is preferable to perform the plating treatment for forming the rustproof layer 5 so as to have a predetermined plating amount.

In the rustproof layer forming step (S14), for example, a Ni plating treatment for forming a Ni plating layer, a Zn plating treatment for forming a Zn plating layer, and a chromate treatment for forming a chromate treatment layer (trivalent chromium formation treatment) are sequentially performed. And a decane coupling treatment to form a decane coupling layer.

<Ni plating treatment>

After the roughening copper plating layer forming step (S13) is completed, the copper foil substrate 2 on which the roughened copper plating layer 4 is formed is washed with water, and then subjected to Ni plating treatment to form a predetermined thickness (for example, 10 nm) on the roughened copper plating layer 4. Ni plating layer of 50 nm or less or more. For example, a plating solution (plating bath) containing 280 g/L or more of 320 g/L or less of nickel sulfate hexahydrate, 40 g/L or more of 50 g/L or less of nickel chloride, and 40 g/L or more of 60 g/L or less of boric acid is used. A plating treatment is performed to form a Ni plating layer. The adjustment of the thickness of the Ni plating layer is performed by adjusting the plating time.

<Zn plating treatment>

After the Ni plating treatment is completed, the copper foil substrate 2 on which the Ni plating layer is formed is washed with water, and then subjected to a Zn plating treatment to form a Zn plating layer having a predetermined thickness (for example, 1 nm or more and 10 nm or less) on the Ni plating layer. For example, a plating solution is formed using a plating solution containing 80 g/L or more and 120 g/L or less of zinc sulfate and 60 g/L or more and 80 g/L or less of sodium sulfate to form a Zn plating layer. The adjustment of the thickness of the Zn plating layer is performed by adjusting the plating time.

<Chromate treatment>

After completion of the Zn plating treatment, the copper foil substrate 2 on which the Zn plating layer is formed is washed with water, and then subjected to chromate treatment to form a chromate treatment layer having a predetermined thickness (for example, 1 nm or more and 10 nm or less) on the Zn plating layer. For example, a reaction type chromate liquid of a trivalent chromium type is used as a treatment liquid to carry out a chemical conversion treatment to form a chromate treatment layer. The adjustment of the thickness of the chromate treatment layer is performed by adjusting the chemical conversion treatment time and the like.

<decane coupling treatment>

After the chromate treatment, the copper foil substrate 2 having the chromate-treated layer formed thereon was washed with water, and then subjected to a decane coupling treatment to form a very thin decane coupling layer on the chromate-treated layer. For example, a decane coupling layer is formed by performing a chemical conversion treatment using a decane coupling liquid as a treatment liquid. The adjustment of the thickness of the decane coupling layer is carried out by adjusting the chemical conversion treatment time, the concentration of the treatment liquid, and the like. According to the above, the surface-treated copper foil 1 according to the present embodiment is manufactured.

[Laminated sheet forming step (S20)]

Next, the laminated plate 10 is formed using the surface-treated copper foil 1. First, the surface-treated copper foil 1 is cut into a predetermined size. Further, a resin substrate (for example, a polyimide film (PI) resin film) 11 having a thermoplastic layer formed on either main surface is prepared. Then, the surface-treated copper foil 1 and the resin are disposed in such a manner that the two surface-treated copper foils 1 are opposed to each other and the surface of each of the surface-treated copper foils 1 on which the roughened copper plating layer is provided is in contact with the thermoplastic layer of the resin substrate 11. Substrate 11. Then, the surface-treated copper foil 1 and the resin substrate 11 are heated to a predetermined temperature (for example, 150° C. or higher and 350° C. or lower) by, for example, a vacuum press, and the surface-treated copper foil 1 and the resin substrate 11 are applied for a predetermined period of time ( For example, a predetermined pressure of 1 minute or more and 120 minutes or less (for example, 0.5 MPa or more and 3.0 MPa) In the following, the surface-treated copper foil 1 is bonded to the resin substrate 11 to form a two-layer CCL as the laminated sheet 10.

When the surface-treated copper foil 1 and the resin base material 11 are bonded together, recrystallization of the copper foil base material 2 (rolled copper foil) which has been subjected to work-hardening by the final cold-rolling treatment causes rolling The copper foil softens. In other words, the surface of the copper foil 1 and the resin substrate 11 are bonded together, and the recrystallization annealing treatment of the copper foil substrate 2 is performed. The re-crystallization of the rolled copper foil causes the rolled copper foil to have a recrystallized structure, and the bending resistance of the rolled copper foil is improved. Further, at least a part of the copper plating layer 3 is also recrystallized together with the copper foil base material 2 by the heating at this time.

[Haze value check step (S30)]

Next, the haze value of the resin substrate 11 was measured. First, at least a part of the surface-treated copper foil 1 (for example, an area required for measuring a haze value and a transparency to be described later) is removed from the laminated plate 10 by, for example, etching, to expose the resin substrate 11. Then, the resin substrate 11 (the portion of the laminate 10 that exposes the resin substrate 11) as the measurement object is placed so as to block the light introduction port 21a of the integrating sphere 21 (see FIG. 2). In a state where the light discharge port 21b is closed by the lid body 24, light is irradiated from the light source 22, and the amount of total light transmitted by the detector 23 is measured. Next, in a state where the cover 24 is removed and the light discharge port 21b is opened, light is irradiated from the light source 22, and the amount of diffused transmitted light is measured by the detector 23. Then, the haze value of the resin substrate 11 at the portion where the surface-treated copper foil 1 was removed was calculated from the above (number 1). When the haze value of the resin substrate 11 is 80% or less, it is judged that the surface-treated copper foil 1 is acceptable. When the haze value of the resin base material 11 exceeds 80%, it is judged that the surface-treated copper foil 1 is a defective product.

[Transparency check step (S40)]

When the haze value measured in the haze value inspection step (S30) is 80% or less, the transparency of the resin substrate 11 at the portion where the surface-treated copper foil 1 is removed from the laminate 10 is measured. First, the resin substrate 11 is placed at the position where the light of the light source 22 is emitted (see Fig. 3(a)). Then, the light is irradiated from the light source 22 in a state where the lid body 24 is removed, and the center sensor 31a and the ring sensor 31b measure the introduction of the resin resin substrate 11 into the integrating sphere 21 from the light introduction port 21a. The amount of light. Then, using the amount of light (IC) received by the center sensor 31a and received by the ring sensor 31b The amount of light (IR) was used to calculate the transparency of the resin substrate 11 from the above (number 2). When the transparency of the resin substrate 11 was 70% or more, it was judged that the surface-treated copper foil 1 was acceptable. When the transparency of the resin substrate 11 is less than 70%, it is determined that the surface-treated copper foil 1 is a defective product. Then, the manufacturing steps of the laminated board 10 are ended.

(4) Effects related to the present embodiment

According to the present embodiment, one or more effects as described below will be exerted.

(a) According to the present embodiment, the surface-treated copper foil 1 is formed in such a manner that the surface-treated copper foil 1 faces and roughens the side of the copper-plated layer 4 and the resin base on the two main faces of the resin substrate. When the surface-treated copper foil 1 is removed from the two main surfaces of the resin substrate after the surface-treated copper foil 1 is bonded, the resin substrate has a haze value of 80% or less and a transparency of 70% or more. Therefore, even when the resin substrate after the etching and the positioning mark are in close contact with each other, when the resin substrate after the etching is disposed at a position apart from the positioning mark, the resin substrate is easily transmitted through the etching. To confirm the positioning mark. Therefore, when an electronic component or the like is mounted on the FPC formed of the laminate 10 formed using the surface-treated copper foil 1, the positioning of the mounting position can be easily performed, and the mounting workability can be improved.

In other words, when the haze value of the resin substrate after the etching is 80% or less, when the resin substrate after the etching and the positioning mark are in close contact with each other, the positioning mark can be confirmed by passing through the resin substrate after the etching. In addition, when the transparency of the resin substrate after the etching is 70% or more, even when the resin substrate after the etching is disposed at a position apart from the positioning mark, the resin substrate after the etching can be transmitted. Confirm the positioning mark. Therefore, in the present embodiment, even when the electronic component or the like is mounted while the FPC is being transported, for example, the positioning of the mounting position can be performed with high precision. Therefore, the present embodiment is particularly effective when mounting an electronic component or the like while transporting the FPC.

(b) By forming the surface-treated copper foil 1 such that the peeling strength between the surface-treated copper foil 1 and the resin substrate is 0.6 N/mm or more, it is possible to suppress the surface-treated copper foil 1 from being resin-based when the laminated sheet 10 is formed. The material 11 peeled off. The predetermined shape is formed even by, for example, removing the surface-treated copper foil 1 of a predetermined portion from the laminated board 10. In the case of the copper wiring, it is also possible to suppress the surface-treated copper foil 1 from peeling off from the resin substrate 11. In other words, the reliability of the FPC can be improved.

(c) By forming the copper plating layer 3 by using a copper plating solution to which an organic compound having a mercapto group is added, it is possible to suppress a decrease in transparency of the resin substrate after etching without lowering the adhesion. Specifically, when an organic compound having a mercapto group which is generally used as a brightening agent is used in an amount suitable for use as a glossing agent (for example, 1.5 mg/L or less), it is possible to suppress a decrease in transparency without lowering the adhesion. That is to say, other uses of an organic compound additive having a mercapto group which is generally used as a glossing agent have been found. As a result, the effects of the above (a) and (b) can be more obtained.

In general, the transparency and adhesion of the resin substrate are in a state-dependent relationship. For example, the higher the transparency of the resin substrate after etching, the lower the adhesion. In order to make the transparency of the resin substrate high, it is necessary to reduce the size of the roughened particles forming the roughened copper plating layer. However, if the size of the roughened particles is reduced, the anchoring effect that can be obtained becomes less, and the adhesion is lowered. On the other hand, by forming the copper plating layer 3 using a copper plating liquid to which an organic compound having a mercapto group is added, the transparency of the resin substrate can be improved and the decrease in adhesion can be suppressed. Regarding this factor, etc., it is being actively studied.

(d) By forming the copper plating layer 3 so as to have a thickness of 0.1 μm or more and 0.6 μm or less, the effects of the above (a) and (b) can be further obtained. Further, when the copper foil base material 2 is recrystallized, the copper plating layer 3 can be recrystallized together with the copper foil base material 2 (rolled copper foil).

(e) By forming the roughened copper plating layer 4 to have a thickness of 0.05 μm or more and 0.3 μm or less, it is possible to suppress the decrease in transparency of the resin substrate while maintaining the adhesion. That is to say, the effects of the above (a) and (b) can be more obtained. Further, it is possible to suppress the processing time (plating time) from being extended to an unnecessary length when the roughened copper plating layer 4 is formed, and it is possible to improve the productivity.

(f) By heating the laminate sheet 10 by bonding the surface-treated copper foil 1 to the resin substrate 11, the recrystallization annealing treatment of the copper foil substrate 2 is performed, whereby the surface-treated copper foil 1 can be reduced in deformation. That is, in the case of using, for example, a rolled copper foil as the copper foil substrate 2, the copper foil substrate 2 before the recrystallization annealing treatment is performed In a solidified state. Therefore, when the surface-treated copper foil 1 is conveyed before the formation of the laminated board 10, the phenomenon that the surface-treated copper foil 1 is broken, or elongated, or broken, or the surface-treated copper foil 1 is wrinkled can be reduced. Thereby, the manufacture of the surface-treated copper foil 1 can be reduced, and productivity can be improved. Further, when the surface-treated copper foil 1 and the resin substrate 11 are bonded together, the resin substrate 11 can be bonded to the surface-treated copper foil 1 which is not deformed.

(Other embodiments of the present invention)

Although an embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described embodiment, and can be appropriately modified without departing from the scope of the invention.

In the above embodiment, the integrating sphere 21 and the light source 22 are respectively disposed such that the distance L between the light emitting position of the light source 22 and the center position of the light introducing port 21a of the integrating sphere 21 and the mounting distance are the same, but are not limited thereto. this. In other words, the integrating sphere 21 and the light source 22 may be disposed such that the distance L between the light emitting position of the light source 22 and the center position of the light introducing port 21a is longer than the mounting distance. In this case, when the transparency of the resin substrate 11 (25) to be measured is measured, the distance between the resin substrate 11 and the light introduction port 21a to be measured is mounted on the optical axis of the light source 22. The resin substrate 11 may be disposed at a position of the distance. Further, the resin substrate 11 may be disposed at a position where the distance between the resin substrate 11 and the light introduction port 21a is longer than the mounting distance. That is, the distance between the light source 22 and the light introducing port 21a or the distance between the resin substrate 11 and the light introducing port 21a may be set to an arbitrary distance or may not coincide with the mounting distance.

In the above embodiment, the organic sulfur compound, the surfactant, and the leveling agent are each added separately, but are not limited thereto. For example, an additive prepared by pre-dispensing two or more of an organic sulfur compound, a surfactant, a leveling agent, and the like may be used. Such an additive may be used singly or in combination with the organic sulfur compound, the surfactant, and the leveling agent described in the above embodiments.

In the above embodiment, the rustproof layer 5 is provided, but is not limited thereto. That is, the rustproof layer 5 may not be provided depending on the purpose, purpose, and the like of the surface-treated copper foil 1. Further, in the above embodiment, the Ni plating layer, the Zn plating layer, and the chromic acid are used. The salt treatment layer and the decane coupling layer constitute the rustproof layer 5, but are not limited thereto. In other words, the layer structure of the rustproof layer 5 can be appropriately changed depending on the purpose, purpose, and the like of the surface-treated copper foil 1. Further, the Ni plating layer may be formed of a Ni alloy containing other metal elements such as Co. The Zn plating layer may also be formed of a Zn alloy containing other metals.

In the above embodiment, the case where the rustproof layer 5 is formed only on the roughened copper plating layer 4 has been described, but the invention is not limited thereto. For example, the main surface of the copper foil base material 2 provided in the surface-treated copper foil 1 on the side opposite to the side on which the roughened copper plating layer 4 is provided (hereinafter, also referred to as surface-treated copper foil 1 for convenience) On the back surface of the copper foil substrate 2), a rustproof layer may be provided. In other words, a Ni plating layer, a Zn plating layer, and a chromate treatment layer may be provided as a rustproof layer in this order from the side of the copper foil substrate 2 on the back surface of the copper foil substrate 2. Thereby, the heat resistance and chemical resistance of the surface-treated copper foil 1 can be improved more.

In the above embodiment, the laminated plate 10 provided with the surface-treated copper foil 1 on both surfaces of the resin substrate 11 has been described, but the invention is not limited thereto. That is, the surface-treated copper foil 1 may be provided on any of the main surfaces of the resin substrate 11.

In the above embodiment, the surface-treated copper foil 1 and the resin substrate 11 are bonded together without using an adhesive, but the invention is not limited thereto. For example, the surface-treated copper foil 1 and the resin substrate may be bonded together via an adhesive. That is, a three-layer CCL can be formed as the laminated board 10.

For example, in the step of roughening the copper plating layer, the roughened particles may be attached to the copper plating layer 3, and further subjected to the copper plating treatment of the capsule to form the roughened copper plating layer 4. That is to say, it is also possible to cover the roughened particles attached to the copper plating layer 3 by a capsule copper plating layer (so-called coated layer). Thereby, the roughened particles can be grown into nodular protrusions. That is to say, the size of the roughened particles can be made larger. In the case of performing the capsule copper plating treatment, the resin substrate has a haze value of 80% or less and a transparency of 70% or more.

In the above embodiment, the cleaning step of performing the electrolytic degreasing treatment and the pickling treatment is performed in the copper plating layer forming step, but the invention is not limited thereto. For example, as the washing step, any of electrolytic degreasing treatment or pickling treatment may be performed. In addition, in the washing step, in addition to the electrolytic degreasing treatment and the pickling treatment, For other processing. In addition, the washing step can also be omitted.

In the above embodiment, the rustproof layer 5 is provided only on the roughened copper plating layer 4, but is not limited thereto. For example, a rustproof layer (hereinafter also referred to as a back rust preventive layer) may be provided on the main surface of the copper foil base material 2 opposite to the side on which the roughened copper plating layer 4 is provided. In this case, it is preferable to simultaneously provide the rustproof layer 5 and the back rustproof layer. Further, the rustproof layer 5 and the back rust preventive layer may be separately provided. For example, the step of forming the back surface rustproof layer may be performed after the step of forming the rustproof layer 5. The layer structure of the back surface rustproof layer may have the same structure as the rustproof layer 5 or may have a structure different from that of the rustproof layer 5. For example, the back rustproof layer may not have a decane coupling layer.

In the above-described embodiment, the surface-treated copper foil 1 and the resin substrate are bonded together, and the copper foil base material 2 provided in the surface-treated copper foil 1 is subjected to recrystallization annealing treatment, but the invention is not limited thereto. That is, the bonding of the surface-treated copper foil 1 and the resin substrate and the recrystallization annealing treatment of the copper foil substrate 2 may be performed in different steps.

In the above embodiment, the case where the surface-treated copper foil 1 is used for the FPC has been described, but the invention is not limited thereto. The surface-treated copper foil 1 according to the present embodiment can also be used for a negative electrode current collecting copper foil of a lithium ion secondary battery, an electromagnetic wave barrier for a plasma display, an antenna of an IC card, or the like.

Example

Next, embodiments of the invention will be described, but the invention is not limited to the embodiments.

<Production of sample>

First, a surface-treated copper foil which is each sample of the samples 1 to 21 was produced.

(sample 1)

Regarding the sample 1, first, as a copper foil substrate, a rolled copper foil having a thickness of 11 μm formed of oxygen-free copper (OFC) was prepared. The copper foil substrate was subjected to electrolytic degreasing treatment and pickling treatment to clean the surface of the copper foil substrate. First, an electrolytic degreasing treatment was carried out using an aqueous solution containing 40 g/L of sodium hydroxide and 20 g/L of sodium carbonate. At this time, the liquid temperature was 40 ° C, the current density was 10 A/dm ² , and the treatment (electroplating) time was 10 seconds. After the electrolytic degreasing treatment is completed, the copper foil substrate is washed with water. Thereafter, the copper foil substrate was immersed in an aqueous solution containing 150 g/L of sulfuric acid and a liquid temperature of 25 ° C for 10 seconds to carry out a pickling treatment. After the pickling treatment is completed, the copper foil substrate is washed with water.

Next, a copper plating layer is formed on any of the main faces of the copper foil substrate. First, as a copper plating solution, an aqueous solution containing the following components: 170 g/L of copper sulfate pentahydrate, 70 g/L of sulfuric acid, 30 mg/L of a powder reagent of SPS as an organic sulfur compound, and a ruthenium group of a surfactant as a surfactant were prepared. CU-BRITE TH-R III series of surfactant liquid 4ml/L, and CU-BRITE TH-R III series of leveling agent liquid 5ml/L, which is a leveling agent And hydrochloric acid (HCL aqueous solution) as a chloride ion 0.15 ml / L. Then, the copper plating solution was allowed to have a liquid temperature of 35 ° C, a current density of 7 A/dm ² , a treatment time of 10 seconds, and a plating treatment to form a copper plating layer having a thickness of 0.1 μm.

After the copper plating layer is formed, the copper foil substrate on which the copper plating layer is formed is washed with water. Thereafter, a roughened copper plating layer is formed on the copper plating layer. As the roughened copper plating solution, an aqueous solution containing the following components: copper sulfate pentahydrate 100 g/L, sulfuric acid 70 g/L, and iron sulfate heptahydrate 20 g/L was prepared. Then, the roughened copper plating solution was subjected to a liquid temperature of 30 ° C, a current density of 60 A/dm ² , and a treatment time of 0.5 second to form a roughened copper plating layer mainly formed of roughened particles and having a thickness of 0.05 μm. In other words, the plating conditions were set so that the thickness (average thickness) when the roughened copper plating layer was uniformly flattened to 0.05 μm, and a roughened copper plating layer was formed.

After the roughened copper plating layer is formed, the copper foil substrate on which the roughened copper plating layer is formed is washed with water. Thereafter, a rustproof layer is formed on the roughened copper plating layer. Specifically, first, an aqueous solution (Ni plating solution) containing 300 g/L of nickel sulfate hexahydrate, 45 g/L of nickel chloride, and 50 g/L of boric acid was prepared. Then, the liquid temperature of the Ni plating solution was set to 50 ° C, the current density was 2 A/dm ² , and the treatment time was 5 seconds, and a Ni plating layer having a thickness of 25 nm was formed on the roughened copper plating layer. After the Ni plating layer is formed, the copper foil substrate is washed with water. Thereafter, an aqueous solution (Zn plating solution) containing 90 g/L of zinc sulfate and 70 g/L of sodium sulfate was prepared. Then, the liquid temperature of the Zn plating solution was changed to 30 ° C, the current density was 1.5 A/dm ² , and the treatment time was 4 seconds, and a Zn plating layer having a thickness of 7 nm was formed on the Ni plating layer. After the Zn plating layer is formed, the copper foil substrate is washed with water. Next, a trivalent chromium formation treatment was performed to form a chromate treatment layer having a thickness of 5 nm on the Zn plating layer. After the chromate treatment layer is formed, the copper foil substrate is washed with water. Then, the copper foil substrate on which the chromate-treated layer was formed was immersed for 5 seconds in a decane coupling liquid having a concentration of 5% of 3-aminopropyltrimethoxydecane and a liquid temperature of 25 ° C. Immediately, it was dried at a temperature of 200 ° C to form a very thin decane coupling treatment layer on the chromate treatment layer.

In parallel with the formation of the rustproof layer on the roughened copper plating layer (while forming the rustproof layer on the roughened copper plating layer), on the opposite side of the copper foil substrate from the side on which the roughened copper plating layer is provided On the main surface, a Ni plating layer, a Zn plating layer, and a chromate treatment layer were sequentially formed as a rustproof layer (back rustproof layer) from one side of the copper foil substrate. It is to be noted that the method of forming the Ni plating layer, the Zn plating layer, and the chromate treatment layer and the Ni plating layer, the Zn plating layer, and the chromate treatment layer which are provided on the roughened copper plating layer as the rustproof layer are same. Thus, a surface-treated copper foil was produced and used as sample 1.

(sample 2~3)

With respect to the samples 2 to 3, the thickness of the copper plating layer was changed as shown in Table 3, respectively. Except for the above, a surface-treated copper foil was produced in the same manner as in the sample 1.

(sample 4~6)

Regarding the sample 4, the average thickness of the roughened copper plating layer was 0.11 μm. That is, the plating treatment conditions at the time of forming the roughened copper plating layer are changed, and the size of the roughened particles is reduced. Except for the above, a surface-treated copper foil was produced in the same manner as in the sample 1. With respect to the samples 5 to 6, the thickness of the copper plating layer was changed as shown in Table 3. Except for the above, a surface-treated copper foil was produced in the same manner as in the sample 4.

(sample 7~9)

Regarding the sample 7, the roughened copper plating layer was made to have an average thickness of 0.3 μm. That is, the plating treatment conditions at the time of forming the roughened copper plating layer are changed to increase the size of the roughened particles. Except for the above, a surface-treated copper foil was produced in the same manner as in the sample 1. With respect to the samples 8 to 9, the thickness of the copper plating layer was changed as shown in Table 3. Except for the above, a surface-treated copper foil was produced in the same manner as in the sample 7.

(Sample 10~11)

Regarding the sample 10, the average thickness of the roughened copper plating layer was 0.03 μm. Except for the above, a surface-treated copper foil was produced in the same manner as in the sample 2. Regarding the sample 11, a copper plating layer was formed using a copper plating solution to which SPS as an organic sulfur compound was not added. Except for this, a surface-treated copper foil was produced in the same manner as in the sample 10.

(Sample 12~13)

Regarding the sample 12, a roughened copper plating layer was formed using a roughened copper plating solution to which no iron sulfate heptahydrate was added. Except for this, a surface-treated copper foil was produced in the same manner as in the sample 10. Regarding the sample 13, no copper plating layer was formed. Except for this, a surface-treated copper foil was produced in the same manner as in the sample 12.

(samples 14 to 16)

Regarding the sample 14, the average thickness of the roughened copper plating layer was 0.35 μm. Except for the above, a surface-treated copper foil was produced in the same manner as in the sample 2. Regarding the sample 15, a copper plating layer was formed using a copper plating liquid to which SPS as an organic sulfur compound was not added. Except for this, a surface-treated copper foil was produced in the same manner as in the sample 14. Regarding the sample 16, a roughened copper plating solution without adding iron sulfate heptahydrate was used to form a roughened copper plating layer. Except for this, a surface-treated copper foil was produced in the same manner as in the sample 14.

(samples 17 to 21)

Regarding the sample 17, a copper plating layer was formed using a copper plating solution to which SPS as an organic sulfur compound was not added. Except for the above, a surface-treated copper foil was produced in the same manner as in the sample 5. Regarding the sample 18, a roughened copper plating layer was formed using a roughened copper plating solution to which no iron sulfate heptahydrate was added. Except for the above, a surface-treated copper foil was produced in the same manner as in the sample 5. Regarding the sample 19, no copper plating layer was formed. Except for the above, a surface-treated copper foil was produced in the same manner as in the sample 1. Regarding the sample 20, no copper plating layer was formed. Except for the above, a surface-treated copper foil was produced in the same manner as in the sample 4. Regarding the sample 21, no copper plating layer was formed. Except for the above, a surface-treated copper foil was produced in the same manner as in the sample 7.

<Production of laminated board>

Each of the surface-treated copper foils of Samples 1 to 21 was used to produce a double-sided FCCL (Flexible Copper Clad Laminate) as a laminate. As the resin substrate, a polyimide film (PIXEO (registered trademark) manufactured by Kaneka Co., Ltd.) having a thickness of 25 μm was used. Each surface-treated copper foil and resin substrate of the samples 1 to 21 were cut into a predetermined size (100 mm in length × 60 mm in width). Then, a surface-treated copper foil as a sample of a predetermined shape was laminated on both surfaces of the resin substrate. At this time, each sample was laminated so that the surface of the surface-treated copper foil of each sample provided with the roughened copper plating layer contacted the resin substrate. Thereafter, the surface-treated copper foil as each sample was bonded to the resin substrate under the conditions of 300 ° C, 5 MPa, and 15 minutes by a vacuum press to produce a double-sided FCCL. In addition, the bonding conditions using a vacuum press are set as follows: heat is applied to the surface-treated copper foil to recrystallize the surface-treated copper foil as each sample to have a recrystallized structure, and the polyimine resin is satisfied. The film manufacturer's recommended conditions enable the surface treated copper foil to be bonded to the resin substrate.

<Evaluation of transparency>

The laminate of the surface-treated copper foil of each of Samples 1 to 21 was evaluated for transparency of the resin substrate. As the transparency evaluation of the resin substrate, the haze value and the transparency of the resin substrate after removing the surface-treated copper foil as each sample from the laminate were measured. Specifically, the laminated plate produced using each sample was subjected to a spray etching treatment with ferric chloride to remove all of the surface-treated copper foil from the laminated plate. That is, a state in which both surfaces (two main faces) of the resin substrate are exposed is formed. Then, the haze-gard plus manufactured by BYK was used to measure the haze value and the transparency of the resin substrate from which the surface-treated copper foil was removed.

<Evaluation of adhesion>

The adhesion of the laminated board formed by using each surface-treated copper foil of the samples 1-21 was evaluated by measuring the peeling strength at the time of peeling the surface-treated copper foil from a resin substrate. The measurement of the peel strength was carried out as follows. First, one main surface of each of the laminated sheets formed by treating the copper foil with each of the surfaces of the samples 1 to 21 (the surface of the surface-treated copper foil on the side opposite to the contact side with the resin substrate) was attached with a width of 1 mm. A masking tape of a specified length. Further, a masking tape is attached to the entire surface of the other main surface of each laminated board. Then, each of the laminated sheets to which the masking tape was attached was subjected to a spray etching treatment using ferric chloride to remove a predetermined portion of the surface-treated copper foil from the laminated sheet (a portion where the masking tape was not attached). After that, the masking tape is removed. Next, the strength at the time of peeling off the surface-treated copper foil from the resin substrate was measured. Specifically, the surface-treated copper foil which was etched to have a width of 1 mm was peeled off from the resin substrate at an angle of 90° (the angle formed by peeling the surface-treated copper foil and the resin substrate was 90°), and the measurement was performed. The force required to peel off the surface-treated copper foil from the resin substrate is taken as the peel strength. The larger the peel strength value thus measured, the higher the adhesion.

<evaluation result>

Tables 1 to 21 show the results of evaluation of the transparency (haze value, transparency) of the resin substrate and the adhesion between the surface-treated copper foil and the resin substrate, respectively.

From the samples 1 to 9, it was confirmed that when the haze value of the resin substrate was 80% or less and the transparency of the resin substrate was 70% or more, the surfaces of the samples 1 to 9 were used. When an electronic component or the like is mounted on the FPC formed of the copper foil, the mounting workability is improved. In other words, when an electronic component or the like is mounted, the positioning mark for determining the mounting position of the electronic component or the like can be easily confirmed through the resin substrate. Specifically, when the resin substrate is in close contact with the positioning mark or when the resin substrate is placed at a position apart from the positioning mark, the positioning mark can be easily confirmed by the resin substrate.

Comparison between sample 1 and sample 19, comparison of sample 4 with sample 20, comparison of sample 7 with sample 21, and comparison of sample 12 with sample 13 confirmed that when a copper plating layer is formed, Improve the transparency of the resin substrate. That is, it was confirmed that the haze value of the resin substrate can be made lower, and the transparency of the resin substrate can be made higher.

The comparison between the sample 5 and the sample 17, and the comparison between the sample 10 and the sample 11 confirmed that the transparency of the resin substrate can be improved when the copper plating layer is formed from the copper plating solution containing the organic sulfur compound.

From the comparison between the sample 2 and the sample 10, it was confirmed that when the average thickness of the roughened copper plating layer is less than 0.05 μm, the transparency of the resin substrate can be improved, but the adhesion tends to be lowered. Further, from the comparison between the sample 8 and the sample 14, it was confirmed that when the average thickness of the roughened copper plating layer was more than 0.30 μm, the adhesion could be improved, but the transparency of the resin substrate was lowered. It was confirmed from the samples 14 and 15 that when the average thickness of the roughened copper plating layer is too thick (thicker than 0.30 μm), the adhesion can be improved regardless of whether or not the copper plating layer is formed from the copper plating solution containing the organic sulfur compound. However, the effect of improving the transparency of the resin substrate cannot be exhibited.

Comparison between sample 5 and sample 18, and comparison between sample 10 and sample 12 confirmed that a copper plating layer containing an organic sulfur compound was used to form a copper plating layer, and coarseness with addition of iron sulfate heptahydrate was used. When the copper plating solution is formed to form a roughened copper plating layer, the growth of the roughened particles constituting the roughened copper plating layer is suppressed, and the roughening particle size can be made uniform. As a result, it was confirmed that the transparency of the resin substrate was improved. Further, from the comparison between the sample 14 and the sample 16, it was confirmed that when the average thickness of the roughened copper plating layer was too thick, a copper plating layer was formed using a copper plating solution containing an organic sulfur compound, and iron sulfate added was used. The roughened copper plating solution of the hydrate forms a roughened copper plating layer, and the effect of improving the transparency of the resin substrate cannot be exhibited.

<Preferred Mode of the Invention>

Hereinafter, preferred embodiments of the present invention are attached.

[Note 1]

According to an aspect of the present invention, a surface-treated copper foil comprising: a copper foil substrate; a copper plating layer formed on the copper foil substrate; and a roughened copper plating layer formed on the copper plating layer The surface-treated copper foil is formed on the two main faces of the resin substrate such that the surface of the surface-treated copper foil opposite to the side on which the roughened copper plating layer is provided is in contact with the resin substrate When the surface-treated copper foil is bonded to the two main surfaces of the resin substrate after the surface-treated copper foil is bonded, the resin substrate has a haze value of 80% or less and a transparency of 70% or more. The peeling strength between the surface-treated copper foil and the resin substrate was 0.6 N/mm or more.

[Note 2]

In the surface-treated copper foil according to the first aspect, it is preferable that the copper plating layer is formed using a copper plating solution to which an organic compound having a mercapto group is added.

[Note 3]

In the surface-treated copper foil according to the second aspect of the invention, it is preferable that the copper plating solution contains the organic compound having a mercapto group of 5 mg/L or more and 60 mg/L or less.

[Note 4]

In the surface-treated copper foil according to any one of the above aspects, the copper-plated layer is preferably formed to have a thickness of 0.1 μm or more and 0.6 μm or less.

[Note 5]

In the surface-treated copper foil according to any one of the above aspects, the roughened copper plating layer is preferably formed to have an average thickness of 0.05 μm or more and 0.30 μm or less.

[Note 6]

According to other aspects of the present invention, there is provided a laminate having: a surface-treated copper foil comprising a copper foil substrate, a copper plating layer formed on the copper foil substrate, and a roughened copper plating layer formed on the copper plating layer; and a resin substrate Forming a surface contact on one side of the roughened copper plating layer, the surface treated copper foil being formed in such a manner that on the two main faces of the resin substrate, the surface treated copper foil is opposed to the surface treated copper foil After the surface-treated copper foil is removed from the two main surfaces of the resin substrate after bonding, the resin substrate has a haze value of 80% or less and a transparency of 70% or more. The surface-treated copper foil and the resin The peel strength between the substrates was 0.6 N/mm or more.

1‧‧‧Surface treated copper foil

2‧‧‧copper substrate

3‧‧‧ copper plating

4‧‧‧Rough copper plating

5‧‧‧Anti-rust layer

10‧‧‧Laminated boards

11‧‧‧Resin substrate

Claims (5)

A surface-treated copper foil comprising: a copper foil substrate; a copper plating layer formed on the copper foil substrate; and a roughened copper plating layer formed on the copper plating layer, the surface treated copper foil being as follows Forming the surface-treated copper foil on the two main surfaces of the resin substrate such that the surface-treated copper foil is opposed to the surface on which the roughened copper plating layer is provided in contact with the resin substrate After removing the surface-treated copper foil from the two main surfaces of the resin substrate, the resin substrate has a haze value of 80% or less and a transparency of 70% or more. The surface-treated copper foil and the resin substrate The peel strength between them was 0.6 N/mm or more. The surface-treated copper foil according to claim 1, wherein the copper plating layer is formed using a copper plating solution to which an organic compound having a mercapto group is added. The surface-treated copper foil according to the first or second aspect of the invention, wherein the copper-plated layer is formed to have a thickness of 0.1 μm or more and 0.6 μm or less. The surface-treated copper foil according to any one of the first aspect, wherein the roughened copper plating layer is formed to have an average thickness of 0.05 μm or more and 0.30 μm or less. A laminated board comprising: a surface-treated copper foil, a copper foil substrate, a copper plating layer formed on the copper foil substrate, and a roughened copper plating layer formed on the copper plating layer; and a resin substrate Formed in contact with a surface on the side where the roughened copper plating layer is provided, the surface-treated copper foil is formed in such a manner that the surface-treated copper foil is formed on both main faces of the resin substrate When the surface-treated copper foil is bonded to the two main surfaces of the resin substrate, the haze value of the resin substrate is 80% or less and the transparency is 70% or more. The peeling strength between the surface-treated copper foil and the resin substrate was 0.6 N/mm or more.