Surface treatment liquid and surface treatment method for rolled copper foil, and method for producing rolled copper foil

Abstract

The invention relates to a surface treatment liquid and a surface treatment method for rolled copper foil, and a method for manufacturing rolled copper foil. In the present invention, the rolled copper foil surface is treated by dissolving the rolled copper foil surface by bringing a surface treatment liquid into contact with the rolled copper foil surface, the surface treatment liquid containing hydrogen peroxide (A), sulfuric acid (B), alcohol (C), and phenylurea (D), the molar ratio of hydrogen peroxide (A) / sulfuric acid (B) being within the range of 0.3-3.0, the sulfuric acid (B) being within the range of 0.5-15.0 mass%, and the alcohol (C) being within the range of 0.1-5.0 mass%. According to a preferable mode of the invention, the surface of the rolled copper foil can be smoothed without generating mountain-shaped etching and pits.

Description

[0001] This application is a divisional application of Chinese patent application filed on March 23, 2018, with application number 201880021257.1 and entitled "Surface treatment liquid and surface treatment method for rolled copper foil and method for manufacturing rolled copper foil". Technical Field

[0002] This invention relates to a surface treatment liquid for rolled copper foil, a surface treatment method for rolled copper foil using the same, and further to a method for manufacturing rolled copper foil. Background Technology

[0003] Rolled copper foil is used in flexible printed wiring boards (FPCs). In recent years, in order to reduce transmission loss in high-frequency regions, increase density, thinness, and further miniaturization and finer spacing, it is preferred to smooth the processing of rolled copper foil.

[0004] For smoothing the surface of copper plates and foils, methods using azoles, halide ions, and silver ions are known (Patent Document 1). However, when this method is used for rolling copper foil, etching occurs along the grain boundaries, resulting in crater-like etching, pits, etc., making smoothing difficult.

[0005] Rolled copper foil is known to have excellent flexibility. To improve flexibility, crystal orientation is controlled to develop a cubic aggregate structure after recrystallization annealing. However, within this uniform crystal structure, there are localized grains with different grain orientations. The etching rate of this part is different from the etching rate of the surrounding area. Therefore, it is believed that after etching, ring-shaped etch pits are formed on the surface of the rolled copper foil (see, for example, Patent Documents 2 and 3).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2010-270365

[0009] Patent Document 2: International Publication No. 2012 / 128098

[0010] Patent Document 3: International Publication No. 2012 / 132857

[0011] Non-patent literature

[0012] Non-patent document 1: Journal of the Printed Circuit Society (Journal of the Printed Circuit Society) "Circuit technology" 9[2]119~124 (1994) Summary of the Invention

[0013] The problem the invention aims to solve

[0014] In this situation, there is a need for a surface treatment solution and surface treatment method that can smooth rolled copper foil without producing ring-shaped etching pits, thereby providing a method for manufacturing rolled copper foil with excellent smoothness.

[0015] However, it is known that copper foil includes rolled copper foil and electrolytic copper foil. Electrolytic copper foil suppresses etching deviations by reducing the size of the grains, making them approximately uniform and consistent with random orientation (Non-Patent Document 1). It is thus known that the etching characteristics differ between rolled copper foil and electrolytic copper foil due to the different crystal structures of copper. This invention relates to a surface treatment liquid and surface treatment method suitable for surface treatment of rolled copper foil, and further, a method for manufacturing rolled copper foil.

[0016] Solution for solving the problem

[0017] Through in-depth research, the inventors discovered that the aforementioned problems can be solved by mixing hydrogen peroxide and sulfuric acid in a specific molar ratio and adding a surface treatment solution with a specific composition containing alcohol-based additives. That is, the present invention is as follows.

[0018] [1] A surface treatment solution for rolling copper foil contains hydrogen peroxide (A), sulfuric acid (B), alcohol (C) and phenylurea (D), wherein the molar ratio of hydrogen peroxide (A) to sulfuric acid (B) is in the range of 0.3 to 3.0, the sulfuric acid (B) is in the range of 0.5 to 15.0% by mass, and the alcohol (C) is in the range of 0.1 to 5.0% by mass.

[0019] [2] According to the surface treatment solution for rolled copper foil described in [1], the contents of the aforementioned hydrogen peroxide (A) and phenylurea (D) are respectively within the following ranges:

[0020] Hydrogen peroxide (A): 0.5–3.0% by mass

[0021] Phenylephrine (D): 0.005–0.3% by mass.

[0022] [3] A surface treatment method for rolled copper foil, wherein the surface of rolled copper foil is dissolved using the surface treatment liquid for rolled copper foil described in [1] or [2] at an etching rate of 0.4 to 4.0 μm / min.

[0023] Furthermore, the present invention is described below.

[0024] [1a] A method for manufacturing rolled copper foil, comprising: contacting a surface treatment liquid containing hydrogen peroxide (A), sulfuric acid (B), alcohol (C) and phenylurea (D), wherein the molar ratio of hydrogen peroxide (A) to sulfuric acid (B) is in the range of 0.3 to 3.0, the content of sulfuric acid (B) is in the range of 0.5 to 15.0% by mass, and the content of alcohol (C) is in the range of 0.1 to 5.0% by mass with the surface of the rolled copper foil to dissolve the surface of the rolled copper foil, thereby treating the surface of the rolled copper foil.

[0025] [2a] According to the method for manufacturing rolled copper foil as described in [1a], the etching rate (E / R) of the rolled copper foil, measured under a processing condition of 35°C, is in the range of 0.4 to 4.0 μm / min:

[0026] Etching rate [μm / min] = (mass before processing [g] - mass after processing for 1 minute [g]) / (processing area [m²]) 2 [× <Specific gravity of copper> 8.92 [g / cm³] 3 ]).

[0027] [3a] According to the method for manufacturing rolled copper foil as described in [1a] or [2a], wherein the SEM image obtained using a scanning electron microscope (SEM) at an accelerating voltage of 5 kV and a magnification of 1000x is processed, and for the contrast of the unevenness of the surface of the rolled copper foil, a single threshold is set to 47, and the level is set to 20 using a histogram, and the brightness of the rolled copper foil before and after the aforementioned surface treatment, calculated using the standard deviation, satisfies the following relationship:

[0028] {(brightness of the treated copper foil) - (brightness of the untreated copper foil)} / (brightness of the untreated copper foil) × 100% < 0%.

[0029] [4a] According to the method for manufacturing rolled copper foil as described in [1a] or [2a], wherein the SEM image obtained using a scanning electron microscope (SEM) at an accelerating voltage of 5 kV and a magnification of 1000x is processed, and for the contrast of the unevenness of the surface of the rolled copper foil, a single threshold is set to 47, and the level is set to 20 using a histogram, and the brightness of the rolled copper foil before and after the aforementioned surface treatment, calculated using the standard deviation, satisfies the following relationship:

[0030] {(brightness of the treated copper foil) - (brightness of the untreated copper foil)} / (brightness of the untreated copper foil) × 100% ≤ -5%.

[0031] [5a] The method for manufacturing rolled copper foil according to any one of [1a] to [4a], wherein the contents of the aforementioned hydrogen peroxide (A) and phenylurea (D) are respectively within the following ranges:

[0032] Hydrogen peroxide (A): 0.5–3.0% by mass

[0033] Phenylephrine (D): 0.005–0.3% by mass.

[0034] [6a] A method for manufacturing rolled copper foil according to any one of [1a] to [5a], wherein the molar ratio of hydrogen peroxide (A) to sulfuric acid (B) is in the range of 0.5 to 0.9.

[0035] [7a] A surface treatment method for rolled copper foil, comprising: dissolving the surface of rolled copper foil using a surface treatment solution containing hydrogen peroxide (A), sulfuric acid (B), alcohol (C) and phenylurea (D), wherein the molar ratio of hydrogen peroxide (A) to sulfuric acid (B) is in the range of 0.3 to 3.0, the content of sulfuric acid (B) is in the range of 0.5 to 15.0% by mass, and the content of alcohol (C) is in the range of 0.1 to 5.0% by mass.

[0036] [8a] The surface treatment method for rolled copper foil according to [7a] includes: dissolving the surface of the rolled copper foil at an etching rate of 0.4 to 4.0 μm / min, as shown in the following formula and measured under treatment conditions at 35°C:

[0037] Etching rate [μm / min] = (mass before processing [g] - mass after processing for 1 minute [g]) / (processing area [m²]) 2 [× <Specific gravity of copper> 8.92 [g / cm³] 3 ]).

[0038] [9a] According to the surface treatment method for rolled copper foil described in [7a] or [8a], wherein the SEM image obtained using a scanning electron microscope (SEM) at an accelerating voltage of 5 kV and a magnification of 1000x is processed, and for the contrast of the unevenness of the surface of the rolled copper foil, a single threshold is set to 47, and the level is set to 20 using a histogram, and the brightness of the rolled copper foil before and after the aforementioned surface treatment, calculated using the standard deviation, satisfies the following relationship:

[0039] {(brightness of the treated copper foil) - (brightness of the untreated copper foil)} / (brightness of the untreated copper foil) × 100% < 0%.

[0040] [10a] According to the surface treatment method for rolled copper foil described in [7a] or [8a], wherein the SEM image obtained using a scanning electron microscope (SEM) at an accelerating voltage of 5 kV and a magnification of 1000x is processed, and for the contrast of the unevenness of the surface of the rolled copper foil, a single threshold is set to 47, and the level is set to 20 using a histogram, and the brightness of the rolled copper foil before and after the aforementioned surface treatment, calculated using the standard deviation, satisfies the following relationship:

[0041] {(brightness of the treated copper foil) - (brightness of the untreated copper foil)} / (brightness of the untreated copper foil) × 100% ≤ -5%.

[0042] [11a] The surface treatment method for rolled copper foil according to any one of [7a] to [10a], wherein the contents of the aforementioned hydrogen peroxide (A) and phenylurea (D) are respectively within the following ranges:

[0043] Hydrogen peroxide (A): 0.5–3.0% by mass

[0044] Phenylephrine (D): 0.005–0.3% by mass.

[0045] [12a] A surface treatment method for rolled copper foil according to any one of [7a] to [11a], wherein the molar ratio of hydrogen peroxide (A) to sulfuric acid (B) is in the range of 0.5 to 0.9.

[0046] [13a] A surface treatment solution for rolled copper foil, comprising hydrogen peroxide (A), sulfuric acid (B), alcohol (C) and phenylurea (D), wherein the molar ratio of hydrogen peroxide (A) to sulfuric acid (B) is in the range of 0.3 to 3.0, the content of sulfuric acid (B) is in the range of 0.5 to 15.0% by mass, and the content of alcohol (C) is in the range of 0.1 to 5.0% by mass.

[0047] [14a] The surface treatment solution for rolled copper foil according to [13a], wherein the contents of the aforementioned hydrogen peroxide (A) and phenylurea (D) are respectively within the following ranges:

[0048] Hydrogen peroxide (A): 0.5–3.0% by mass

[0049] Phenylephrine (D): 0.005–0.3% by mass.

[0050] [15a] The surface treatment solution for rolled copper foil according to [13a] or [14a], wherein the molar ratio of hydrogen peroxide (A) to sulfuric acid (B) is in the range of 0.5 to 0.9.

[0051] The effects of the invention

[0052] According to a preferred embodiment of the present invention, a rolled copper foil with excellent smoothness can be obtained by using the processing solution for rolled copper foil of the present invention. By using the rolled copper foil obtained in the present invention, flexible printed circuit films capable of reducing transmission losses in high-frequency regions, increasing density, thinning, and further miniaturizing and finer spacing can be manufactured. Attached Figure Description

[0053] Figure 1 The surface observation image of untreated rolled copper foil obtained by scanning electron microscopy (hereinafter SEM) (1000x magnification).

[0054] Figure 2 The images are surface observation images obtained using SEM (1000x magnification) for Examples 1-9.

[0055] Figure 3 The images are surface observation images obtained using SEM (1000x magnification) in Examples 10-14.

[0056] Figure 4 For comparison, the surface observation images obtained using SEM (1000x magnification) are shown in Examples 1-6. Detailed Implementation

[0057] [Manufacturing method of rolled copper foil]

[0058] The method for manufacturing rolled copper foil of the present invention is characterized in that a surface treatment solution containing hydrogen peroxide (A), sulfuric acid (B), alcohol (C) and phenylurea (D), wherein the molar ratio of hydrogen peroxide (A) to sulfuric acid (B) is in the range of 0.3 to 3.0, the sulfuric acid (B) is in the range of 0.5 to 15.0% by mass, and the alcohol (C) is in the range of 0.1 to 5.0% by mass, is brought into contact with the surface of the rolled copper foil to dissolve the surface of the rolled copper foil, thereby treating the surface of the rolled copper foil.

[0059] According to a preferred embodiment of the present invention, the surface of the rolled copper foil is dissolved by contacting the surface treatment liquid having the above composition with the surface of the rolled copper foil, thereby making it less likely to produce etching along the grain boundaries and obtaining a rolled copper foil with excellent surface smoothness.

[0060] [Surface treatment solution for rolled copper foil]

[0061] The surface treatment solution for rolled copper foil used in this invention contains hydrogen peroxide (A), sulfuric acid (B), alcohol (C), and phenylurea (D). These are described in detail below.

[0062] [Hydrogen peroxide (A)]

[0063] Hydrogen peroxide (A) in this invention functions as an oxidizing agent for copper.

[0064] There are no limitations on the hydrogen peroxide (A) used in this invention. Commercially available aqueous solutions of hydrogen peroxide can be used, such as 60% industrial / electronics grade hydrogen peroxide manufactured by Mitsubishi Gas Chemical Co., Ltd.

[0065] The concentration of hydrogen peroxide (A) in the surface treatment solution is preferably 0.5 to 3.0% by mass, more preferably 0.6 to 2.5% by mass, and particularly preferably 0.8 to 2.0% by mass. When the concentration of hydrogen peroxide is within the above range, a good surface condition of copper and a suitable copper dissolution rate can be obtained.

[0066] Furthermore, the molar ratio of hydrogen peroxide (A) to sulfuric acid (B) is 0.3 to 3.0, preferably 0.4 to 3.0, and more preferably 0.5 to 3.0. The molar ratio of hydrogen peroxide (A) to sulfuric acid (B) is particularly preferably 0.5 to 0.9. By controlling the molar ratio within this range, a good surface condition of copper and a suitable copper dissolution rate can be obtained. Additionally, the smoothness of the rolled copper foil surface can be improved.

[0067] [Sulfuric Acid (B)]

[0068] In this invention, sulfuric acid (B) functions as an etchant for copper oxidized by hydrogen peroxide.

[0069] There are no limitations on the sulfuric acid (B) used in this invention; for example, a 95% premium grade reagent manufactured by Wako Pure Chemical Industries, Ltd. may be suitable.

[0070] The concentration of sulfuric acid (B) in the surface treatment solution is 0.5–15.0% by mass, preferably 0.6–15.0% by mass, and more preferably 1.0–5.0% by mass. Within this range, a good surface condition of copper and a suitable copper dissolution rate can be obtained.

[0071] [Alcohol(C)]

[0072] The alcohol (C) in this invention includes all common alcohols and is a component that improves the smoothness of the surface of rolled copper foil.

[0073] Specific examples of alcohols (C) include monohydric alcohols such as methanol, ethanol, and propanol; dihydric alcohols such as ethylene glycol and propylene glycol; alcohols with three or more components; and dihydric alcohol ethers such as polyethylene glycol. Two or more of these can also be used in combination.

[0074] The concentration of alcohol (C) in the surface treatment solution is 0.1 to 5.0% by mass, preferably 0.5 to 5.0% by mass. By being within this range, a smooth surface condition of the rolled copper foil can be obtained.

[0075] [Phenylurea(D)]

[0076] The phenylurea (D) in this invention is a component that improves the stability of hydrogen peroxide.

[0077] There are no limitations on the phenylurea (D) used in this invention; for example, phenylurea manufactured by Wako Pure Chemical Industries, Ltd. may be used appropriately.

[0078] The concentration of phenylurea (D) in the surface treatment solution is preferably 0.005–0.3% by mass, more preferably 0.005–0.15% by mass, and even more preferably 0.005–0.1% by mass. Within this range, the decomposition of hydrogen peroxide can be suppressed. Furthermore, by appropriately adjusting the amount of phenylurea (D), the smoothness of the rolled copper foil surface can be improved.

[0079] [Other ingredients]

[0080] The surface treatment liquid of the present invention may also contain water and various commonly used additives, to a extent that it does not hinder the effect of the present invention.

[0081] For example, known etching rate modifiers such as alkalis, organic carboxylic acids, and organic amine compounds can be added as needed, along with a copper ion supply source to stabilize the etching rate.

[0082] In addition, the preferred water is water that has been treated by distillation, ion exchange, filtration, various adsorption processes to remove metal ions, organic impurities, particles, etc., and even more preferably pure water, and especially preferably ultrapure water.

[0083] [Manufacturing of surface treatment solution for rolled copper foil]

[0084] The surface treatment solution for rolled copper foil is manufactured by uniformly mixing hydrogen peroxide (A), sulfuric acid (B), alcohol (C), phenylurea (D), and other components as needed.

[0085] Surface treatment methods for rolled copper foil

[0086] In this invention, the surface of the rolled copper foil is dissolved by contacting it with the aforementioned surface treatment solution, thereby treating the surface of the rolled copper foil. According to a preferred embodiment of the invention, treating the surface of the rolled copper foil with the aforementioned surface treatment solution results in excellent surface smoothness. There are no particular limitations on the method of contacting the surface treatment solution with the surface of the rolled copper foil; known methods such as immersion or spraying can be used.

[0087] As described above, the surface treatment liquid for rolled copper foil of the present invention can be used in known surface treatment methods for rolled copper foil, such as immersion and spraying. The rolled copper foil used in the present invention is a commonly known rolled copper foil, which is a copper foil with flexibility and high crystal orientation manufactured by repeatedly plasticizing and heat-treating copper or copper alloy ingots using rolling rolls.

[0088] There is no limitation on the operating temperature of the aforementioned surface treatment solution, but it is typically 20–50°C, preferably 25–40°C, and more preferably 25–35°C. The higher the operating temperature of the aforementioned surface treatment solution, the faster the copper dissolves; however, if the temperature exceeds 50°C, the decomposition of hydrogen peroxide becomes rapid, which is therefore not preferred.

[0089] There is no limitation on the treatment time of the rolled copper foil surface using the aforementioned surface treatment solution, but it is usually 1 to 600 seconds, preferably 5 to 300 seconds, more preferably 10 to 180 seconds, and particularly preferably 15 to 120 seconds.

[0090] There is no limitation on the dissolution rate of the rolled copper foil using the aforementioned surface treatment solution, but if the etching rate (E / R) is typically 0.4 to 4.0 μm / min, preferably 1.0 to 3.5 μm / min or 1.5 to 3.0 μm / min under processing conditions at 35°C, the etching time can be shortened, and therefore it is particularly preferred.

[0091] According to a preferred embodiment of the present invention, the rolled copper foil of the present invention, which has been surface-treated with the aforementioned surface treatment liquid, has excellent surface smoothness and is therefore suitable for use in flexible printed wiring boards and the like.

[0092] According to a preferred embodiment of the present invention, for the obtained rolled copper foil, image processing is performed on the SEM image obtained using a scanning electron microscope (SEM) at an accelerating voltage of 5 kV and a magnification of 1000x. For the contrast of the unevenness of the rolled copper foil surface, a single threshold is set to 47, and a histogram is used with a level of 20. The brightness of the rolled copper foil before and after the aforementioned surface treatment, calculated using standard deviation, satisfies the following relationship:

[0093] {(brightness of the treated copper foil) - (brightness of the untreated copper foil)} / (brightness of the untreated copper foil) × 100% < 0%.

[0094] Excellent smoothness. The value (%) shown in the above formula is more preferably -5% or less, and even more preferably -10% or less.

[0095] Example

[0096] The present invention will be specifically described below through examples, but the implementation methods can be appropriately modified as long as the effects of the present invention are achieved.

[0097] [Evaluation method]

[0098] <SEM observation>

[0099] Using a scanning electron microscope (SEM: S-3400N manufactured by Hitachi High-Technologies Corporation), the surface state of the rolled copper foil was measured under the conditions of an acceleration voltage of 5 kV and a magnification of 1000 times.

[0100] From the SEM image, the case where there is no grain boundary etching is regarded as being smoothed.

[0101] The evaluation of the surface state is carried out as described below.

[0102] Case where there is no grain boundary etching: "Excellent"

[0103] Case where there is grain boundary etching: "Failed"

[0104] <Brightness measurement of copper surface>

[0105] The SEM image was analyzed using the analysis software WinROOF2013 (manufactured by Mitani Shoko Co., Ltd.). For the contrast of the concave and convex parts of the rolled copper foil surface, a single threshold value was set at 47, the number of levels was set at 20 using a histogram, and the brightness was obtained using the standard deviation.

[0106] The lower the brightness, the higher the smoothness, and the higher the brightness, the lower the smoothness. Based on the brightness of the untreated copper foil being 28.4 as a reference, the smoothness of the treated copper foil was judged based on the following formula.

[0107] {(Brightness of the treated copper foil)-(Brightness of the untreated copper foil)} / (Brightness of the untreated copper foil)×100%={(Brightness of the treated copper foil)-28.4} / 28.4×100%

[0108] -10% or less: "Excellent"

[0109] Less than -10% to -5% or less: "Good"

[0110] Less than -5% to less than 0%: "Pass"

[0111] 0% or more: "Failed".

[0112] <Etching rate (E / R) measurement method>

[0113] A 1-minute dipping and stirring treatment was carried out, and it was calculated by the mass method based on the following formula.

[0114] Etching rate [μm / minute]=(Mass before treatment [g]-Mass after 1-minute treatment [g]) / (Treatment area [m2 [Specific gravity of copper] 8.92 g / cm³ 3 ])

[0115] [Example 1]

[0116] Weigh out 2.00g of hydrogen peroxide (A) (60% hydrogen peroxide manufactured by Mitsubishi Gas Chemical Co., Ltd.), 8.42g of sulfuric acid (B) (95% premium reagent manufactured by Wako Pure Chemical Industries, Ltd.), 1.00g of alcohol (C) (polyethylene glycol 600 (PEG600) manufactured by Wako Pure Chemical Industries, Ltd. (Wako Grade 1)), 0.06g of phenylurea (D) (manufactured by Wako Pure Chemical Industries, Ltd.), and 23.60g of copper sulfate pentahydrate (manufactured by Wako Pure Chemical Industries, Ltd.), then add ultrapure water to make the total mass 200g, and stir until homogeneous to prepare a surface treatment solution for rolled copper foil.

[0117] For rolled copper foil HA-V2 foil cut to 30mm square, the above surface treatment solution was used, with the stirring speed set at 200rpm and the liquid temperature set at 30 degrees, and 3μm etching was performed by immersion stirring.

[0118] The results are shown in Table 1 and... Figure 2 As shown, the measured brightness of the substrate is less than 28.4% of that of the untreated substrate. Furthermore, due to... Figure 2 It can be seen that the surface was not etched into a ring shape, thus exhibiting good smoothness.

[0119] [Examples 2-9]

[0120] The composition was changed to that shown in Table 1, and the operation was otherwise the same as in Example 1. The results are shown in Table 1 and... Figure 2 As shown, the measured brightness of the substrate is less than 28.4% of that of the untreated substrate. Furthermore, due to... Figure 2 It can be seen that the surface was not etched into a ring shape, thus exhibiting good smoothness.

[0121] [Examples 10-14]

[0122] The composition was changed to that shown in Table 1, and the operation was otherwise the same as in Example 1. The results are shown in Table 1 and... Figure 3 As shown, the measured brightness of the substrate is less than 28.4% of that of the untreated substrate. Furthermore, due to... Figure 3 It can be seen that the surface was not etched into a ring shape, thus exhibiting good smoothness.

[0123] [Comparative Examples 1-5]

[0124] The composition was changed to that shown in Table 2, and the experiments were conducted in the same manner as in Example 1. The results are shown in Table 2 and... Figure 4 As shown, the measured brightness of the substrate is greater than 28.4% of the untreated substrate. Furthermore, from... Figure 4 It can be seen that the surface is etched into a ring-shaped pattern, thus failing to achieve good smoothness.

[0125] [Comparative Example 6]

[0126] The composition was changed to that shown in Table 3 (the embodiment of Patent Document 1), and the experiments were conducted in the same manner as in Example 1. The results are shown in Table 3 and... Figure 4 As shown. By Figure 4 It can be seen that although the surface was not etched into a ring shape, the measured brightness was greater than that of the untreated substrate (28.4), thus good smoothness could not be obtained.

[0127] [Table 1]

[0128]

[0129] [Table 2]

[0130]

[0131] [Table 3]

[0132]

[0133] Industrial availability

[0134] The rolled copper foil obtained by the manufacturing method of the present invention has excellent surface smoothness and can therefore be suitable for use in flexible printed wiring boards (FPCs) and the like.

Claims

1. A method of manufacturing a rolled copper foil, comprising: A surface treatment liquid containing hydrogen peroxide (A), sulfuric acid (B), alcohol (C), and phenylurea (D), and having a molar ratio of hydrogen peroxide (A) to sulfuric acid (B) in the range of 0.3 to 3.0, a content of hydrogen peroxide (A) in the range of 0.5 to 3.0 mass%, a content of sulfuric acid (B) in the range of 0.5 to 15.0 mass%, a content of alcohol (C) in the range of 0.1 to 5.0 mass%, and a content of phenylurea (D) in the range of 0.005 mass% to 0.03 mass%, and in which alcohol (C) is selected from dihydric alcohols, is brought into contact with the surface of a rolled copper foil, and the surface of the rolled copper foil is dissolved, whereby the surface of the rolled copper foil is treated.

2. The method of manufacturing a rolled copper foil according to claim 1, wherein, The etching rate (E / R) of the rolled copper foil represented by the following formula is in the range of 0.4 to 4.0 μm / minute, which is measured under a treatment condition of 35°C: Etching rate [μm / min] = (mass before treatment [g] - mass after 1 min of treatment [g]) / (treated area [m 2 ] x <specific gravity of copper> 8.92 [g / cm 3 ]). Etching rate [μm / min] = (mass before treatment [g] - mass after 1 min of treatment [g]) / (treated area [m 2 ] x <specific gravity of copper> 8 3. The method of producing a rolled copper foil according to claim 1 or 2, wherein, The brightness of the rolled copper foil before and after the surface treatment satisfies the following relationship, which is obtained by image processing of a SEM image obtained using a scanning electron microscope (SEM) under a condition of an acceleration voltage of 5 kV and a magnification of 1000 times, and by setting a single threshold value to 47 for the contrast of the concave-convex portion of the surface of the rolled copper foil, and by setting the number of classes to 20 using a histogram, and by using a standard deviation: {(brightness of the treated copper foil) - (brightness of the untreated copper foil)} / (brightness of the untreated copper foil) x 100% < 0%.

4. The production method of a rolled copper foil according to claim 1 or 2, wherein, The brightness of the rolled copper foil before and after the surface treatment satisfies the following relationship, which is obtained by image processing of a SEM image obtained using a scanning electron microscope (SEM) under a condition of an acceleration voltage of 5 kV and a magnification of 1000 times, and by setting a single threshold value to 47 for the contrast of the concave-convex portion of the surface of the rolled copper foil, and by setting the number of classes to 20 using a histogram, and by using a standard deviation: {(brightness of the treated copper foil) - (brightness of the untreated copper foil)} / (brightness of the untreated copper foil) x 100% ≤ -5%.

5. The production method of the rolled copper foil according to any one of claims 1 to 4, wherein The molar ratio of hydrogen peroxide (A) to sulfuric acid (B) is in the range of 0.5 to 0.

9.

6. A surface treatment method for a rolled copper foil, comprising: A surface treatment liquid for a rolled copper foil containing hydrogen peroxide (A), sulfuric acid (B), alcohol (C), and phenylurea (D), and having a molar ratio of hydrogen peroxide (A) to sulfuric acid (B) in the range of 0.3 to 3.0, a content of hydrogen peroxide (A) in the range of 0.5 to 3.0 mass%, a content of sulfuric acid (B) in the range of 0.5 to 15.0 mass%, a content of alcohol (C) in the range of 0.1 to 5.0 mass%, and a content of phenylurea (D) in the range of 0.005 mass% to 0.03 mass%, and in which alcohol (C) is selected from dihydric alcohols, is used to dissolve the surface of a rolled copper foil.

7. The surface treatment method of a rolled copper foil according to claim 6, comprising: The surface of a rolled copper foil is dissolved at a rate of 0.4 to 4.0 μm / minute of the etching rate of the rolled copper foil represented by the following formula, which is measured under a treatment condition of 35°C: Etching rate [μm / min] = (mass before treatment [g] - mass after 1 min of treatment [g]) / (treated area [m 2 ] x <specific gravity of copper> 8.92 [g / cm 3 ]).

8. The surface treatment method of a rolled copper foil according to claim 6 or 7, wherein For the SEM image obtained using a scanning electron microscope (SEM) under conditions of an accelerating voltage of 5 kV and a magnification of 1000 times, the contrast of the concave-convex portions of the rolled copper foil surface was subjected to image processing, a single threshold value was set to 47, the number of classes was set to 20 using a histogram, and the brightness of the rolled copper foil before and after the surface treatment satisfied the following relationship: {(brightness of the treated copper foil) - (brightness of the untreated copper foil)} / (brightness of the untreated copper foil) x 100% < 0%.

9. The surface treatment method of a rolled copper foil according to claim 6 or 7, wherein, For the SEM image obtained using a scanning electron microscope (SEM) under conditions of an accelerating voltage of 5 kV and a magnification of 1000 times, the contrast of the concave-convex portions of the rolled copper foil surface was subjected to image processing, a single threshold value was set to 47, the number of classes was set to 20 using a histogram, and the brightness of the rolled copper foil before and after the surface treatment satisfied the following relationship: {(brightness of the treated copper foil) - (brightness of the untreated copper foil)} / (brightness of the untreated copper foil) x 100% ≤ -5%.

10. The surface treatment method of a rolled copper foil according to any one of claims 6 to 9, wherein The molar ratio of hydrogen peroxide (A) to sulfuric acid (B) is in the range of 0.5 to 0.

9.

11. A surface treatment liquid for a rolled copper foil, which contains hydrogen peroxide (A), sulfuric acid (B), alcohol (C), and phenylurea (D), the molar ratio of hydrogen peroxide (A) to sulfuric acid (B) is in the range of 0.3 to 3.0, the content of hydrogen peroxide (A) is in the range of 0.5 to 3.0 mass%, the content of sulfuric acid (B) is in the range of 0.5 to 15.0 mass%, the content of alcohol (C) is in the range of 0.1 to 5.0 mass%, the content of phenylurea (D) is in the range of 0.005 mass% to 0.03 mass%, and alcohol (C) is selected from dihydric alcohol.

12. The surface treatment liquid for a rolled copper foil according to claim 11, wherein The molar ratio of hydrogen peroxide (A) to sulfuric acid (B) is in the range of 0.5 to 0.9.

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