Electrolytic copper foil and electrolytic copper foil surface treatment process

Abstract

The application discloses an electrolytic copper foil and an electrolytic copper foil surface treatment process. The electrolytic copper foil sequentially undergoes the following processes in order: copper foil unwinding, pickling, roughening I, solidification I, roughening II, solidification II, roughening III, solidification III, water washing I, ashing, water washing II, passivation, water washing III, water washing IV, silane spraying, drying and copper foil winding. The process conditions of roughening are as follows: temperature 20-30 DEG C, copper ion concentration 9-15 g / L, sulfuric acid concentration 150-190 g / L, sodium tungstate concentration 10-60 ppm, cobalt sulfate concentration 5-45 ppm, liquid inlet end current density 10-50 A / dm 2 , liquid outlet end current density 5-30 A / dm 2 ; the process conditions of solidification are as follows: temperature 35-50 DEG C, copper ion concentration 40-60 g / L, sulfuric acid concentration 90-120 g / L, sodium tungstate concentration 10-60 ppm, titanium sulfate concentration 0.1-3 g / L, liquid inlet end current density 10-30 A / dm 2 , liquid outlet end current density 10-30 A / dm 2 . Through the above design, the heat loss rate of the high-temperature peel strength of the electrolytic copper foil can be reduced.

Description

Technical Field

[0001] This application relates to the field of electrolytic copper foil preparation, and more particularly to an electrolytic copper foil and an electrolytic copper foil surface treatment process. Background Technology

[0002] Electrolytic copper foil is an important raw material in the electronics and electrical industries. It can be used to produce copper-clad laminates, which are then used to manufacture printed circuit boards. The production process of electrolytic copper foil generally includes: electrolyte preparation, electrolytic foil production, surface treatment, and slitting and packaging. Surface treatment refers to electroplating the surface of the copper foil, using copper, zinc, and chromium plating to improve various performance indicators of the raw foil, such as peel resistance and oxidation resistance.

[0003] The high-temperature peel strength heat loss rate of copper foil produced by current technology is relatively high. According to the national standard GB / T 29871-2013, the peel strength heat loss rate should be around 10%. However, the heat loss rate of electrolytic copper foil after existing surface treatment processes is generally 30-40%, and occasionally there are cases of non-compliance (>50%). Summary of the Invention

[0004] The purpose of this application is to provide an electrolytic copper foil and an electrolytic copper foil surface treatment process to reduce the heat loss rate of the high-temperature peel strength of the electrolytic copper foil.

[0005] This application discloses a surface treatment process for electrolytic copper foil, wherein the electrolytic copper foil undergoes the following steps in sequence: unwinding, pickling, roughening I, curing I, roughening II, curing II, roughening III, curing III, water washing I, ashing, water washing II, passivation, water washing III, water washing IV, silane spraying, drying, and copper foil winding.

[0006] The process conditions for roughening I, roughening II, and roughening III are as follows: the temperature of the roughening bath is 20-30℃, the copper ion concentration is 9-15 g / L, the sulfuric acid concentration is 150-190 g / L, the sodium tungstate concentration is 10-60 ppm, the cobalt sulfate concentration is 5-45 ppm, and the influent flow rate is 5-10 m³ / h. 3 / h, inlet current density is 10-50A / dm 2 The current density at the liquid outlet is 5-30 A / dm³. 2 The process conditions for Curing I, Curing II, and Curing III are as follows: the temperature of the curing bath is 35-50℃, the copper ion concentration is 40-60 g / L, the sulfuric acid concentration is 90-120 g / L, the sodium tungstate concentration is 10-60 ppm, the titanium sulfate concentration is 0.1-3 g / L, and the inlet flow rate is 5-10 m³ / L. 3 / h, inlet current density is 10-30A / dm 2The current density at the liquid outlet is 10-30 A / dm³. 2 .

[0007] Optionally, the ashing process conditions are as follows: the temperature of the ashing bath is 30-40℃, the zinc ion concentration is 2.0-4.0 g / L, the nickel ion concentration is 1.0-2.0 g / L, the potassium pyrophosphate concentration is 40-60 g / L, the pH value is 9.0-11.0, and the influent flow rate is 5-10 m³ / h. 3 / h, the optical current density is 1-10A / dm 2 The surface current density is 1-10 A / dm. 2 .

[0008] Optionally, in the ashing process, the ratio of zinc ion concentration to nickel ion concentration is 2:1.

[0009] Optionally, the passivation process conditions are as follows: the temperature of the passivation bath is 20-30℃, the chromium ion concentration is 0.5-1.5g / L, the pH value is 10.0-12.0, and the influent flow rate is 5-10m³. 3 / h, the optical current density is 1-10A / dm 2 The surface current density is 1-10 A / dm. 2 .

[0010] Optionally, in the water washing I, water washing II, water washing III and water washing IV processes, the water washing temperature is 20-25℃, pure water is used for water washing, and the pure water quality is: conductivity ≤5μs / cm, turbidity ≤2, pH=6.8-7.6, chloride ion content ≤1ppm.

[0011] Optionally, in the silane spraying process, a silane coupling agent is used for spraying, and the temperature of the silane coupling agent is 10-40℃ and the flow rate is 1-7m³ / h. 3 / h, content is 5‰.

[0012] Optionally, in the copper foil unwinding and rewinding processes, the linear speed of unwinding and rewinding is 20-40 m / min.

[0013] Optionally, in the pickling process, the temperature is 20-30℃, the copper ion concentration is 9-15g / L, and the sulfuric acid concentration is 150-190g / L.

[0014] This application also discloses an electrolytic copper foil, which is prepared by the electrolytic copper foil surface treatment process described above.

[0015] Optionally, the electrolytic copper foil includes reversed copper foil.

[0016] Compared to current surface treatment processes, this application improves the heat resistance, corrosion resistance, and high-temperature peel strength of electrolytic copper foil by adding sodium tungstate and cobalt sulfate in the roughening process; and improves the deep plating capability of the copper foil by adding sodium tungstate and titanium sulfate in the curing process. The combination results in higher high-temperature peel strength and lower heat loss of the electrolytic copper foil, thereby achieving the goal of reducing the heat loss rate of high-temperature peel strength of electrolytic copper foil. Attached Figure Description

[0017] The accompanying drawings, which form part of the specification, are used to provide a further understanding of the embodiments of this application and illustrate the implementation methods of this application, together with the textual description, to explain the principles of this application. Obviously, the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any creative effort. In the drawings:

[0018] Figure 1 This is a flowchart of a surface treatment process for electrolytic copper foil provided in an embodiment of this application. Detailed Implementation

[0019] It should be understood that the terminology, specific structural and functional details used herein are merely for describing particular embodiments and are representative. However, this application may be implemented in many alternative forms and should not be construed as being limited to the embodiments set forth herein.

[0020] The present application will now be described in detail with reference to the accompanying drawings and optional embodiments.

[0021] Figure 1 This is a flowchart of a surface treatment process for electrolytic copper foil provided in an embodiment of this application, such as... Figure 1 As shown, the specific steps of electrolytic copper foil are as follows: copper foil unwinding, pickling, roughening I, curing I, roughening II, curing II, roughening III, curing III, water washing I, ashing, water washing II, passivation, water washing III, water washing IV, silane spraying, drying, and copper foil winding.

[0022] It should be noted that in the actual production process, the roughening process, curing process and / or water washing process can be reduced or increased as needed, which does not affect the use of the technical solution in this application.

[0023] The purpose of this application is to provide a surface treatment process to improve the high-temperature peel strength of copper foil. By adding electroplating additives during the roughening and curing process of the electrolytic copper foil surface treatment, the electrolytic copper foil has good corrosion resistance and adhesion during the roughening and curing process. In addition, with the addition of a specially formulated heat-resistant layer process, the heat loss rate of high-temperature peel strength can be controlled within 10% under the test method required by the customer, thus solving the problem of low high-temperature peel strength of electrolytic copper foil in the prior art.

[0024] Specifically, in the roughening process, namely roughening I, roughening II, and roughening III, the temperature of the roughening tank solution is 20-30℃, the copper ion concentration is 9-15g / L, the sulfuric acid concentration is 150-190g / L, the sodium tungstate concentration is 10-60ppm, the cobalt sulfate concentration is 5-45ppm, and the influent flow rate is 5-10m³ / h. 3 / h, the current density at the inlet (descent) end is 10-50 A / dm 2 The current density at the liquid outlet (rising end) is 5-30 A / dm³. 2 .

[0025] The conditions for the curing process, namely Curing I, Curing II, and Curing III, are as follows: the temperature of the curing bath is 35-50℃, the copper ion concentration is 40-60 g / L, the sulfuric acid concentration is 90-120 g / L, the sodium tungstate concentration is 10-60 ppm, the titanium sulfate concentration is 0.1-3 g / L, and the inlet flow rate is 5-10 m³ / L. 3 / h, the current density at the inlet (descent) end is 10-30 A / dm 2 The current density at the liquid outlet (rising end) is 10-30 A / dm³. 2 .

[0026] The main function of roughening processes I, II, and III is to deposit a layer of dendritic cuprous oxide particles on the rough surface of the copper foil, increasing the specific surface area. The main function of curing processes I, II, and III is to deposit very dense and fine copper crystals on the cuprous oxide particles formed after roughening, firmly encapsulating these dendritic particles, increasing the adhesion between the copper foil and the substrate, and improving the peel strength of the copper foil.

[0027] Compared to current surface treatment processes, this application improves the heat resistance, corrosion resistance, and high-temperature peel strength of electrolytic copper foil by adding sodium tungstate and cobalt sulfate during the roughening process; and improves the deep plating capability of the copper foil by adding sodium tungstate and titanium sulfate during the curing process. In summary, by adding electroplating additives during the surface treatment roughening and curing processes, the deep plating capability, high-temperature resistance, corrosion resistance, and adhesion of the copper foil are improved during the roughening and curing electroplating processes. This results in higher high-temperature peel strength and lower heat loss of the electrolytic copper foil, thereby achieving the goal of reducing the heat loss rate of the high-temperature peel strength of the electrolytic copper foil.

[0028] In general surface treatment processes, the sulfuric acid concentration in the roughening process is typically 120 g / L, and the sulfuric acid concentration in the curing process is typically 60 g / L. In contrast, the embodiments of this application increase the acid content in the roughening and curing processes, thereby reducing power consumption during production.

[0029] Since sodium tungstate and cobalt sulfate are used as electroplating additives in roughening I, roughening II and roughening III processes in this application embodiment, replacing the auxiliary agent (arsenic trioxide) in the roughening electrolyte of general surface treatment process, and since arsenic trioxide is a highly toxic material, the technical solution in this application embodiment ensures the safety of production.

[0030] Furthermore, in the embodiments of this application, the electroplating additives in the roughening process are sodium tungstate and cobalt sulfate, and the electroplating additives in the curing process are sodium tungstate and titanium sulfate. Through numerous experiments, the inventors discovered that compared to using the same electroplating additive scheme in both the roughening and curing processes, the design of the embodiments of this application is more conducive to improving the heat resistance of the electrolytic copper foil and reducing the heat loss rate of the electrolytic copper foil's high-temperature peel strength.

[0031] In the pickling process, the same electrolyte as in the roughening process is used, specifically, the temperature is 20-30℃, the copper ion concentration is 9-15 g / L, and the sulfuric acid concentration is 150-190 g / L. The main purpose of the pickling process is to clean the surface oxide layer formed on the master coil due to storage, ensuring the uniformity of subsequent electroplating.

[0032] In the ashing process, the temperature of the ashing bath is 30-40℃, the zinc ion concentration is 2.0-4.0 g / L, the nickel ion concentration is 1.0-2.0 g / L, the potassium pyrophosphate concentration is 40-60 g / L, the pH value is 9.0-11.0, and the influent flow rate is 5-10 m³ / h. 3 / h, the optical current density is 1-10A / dm 2 The surface current density is 1-10 A / dm. 2 .

[0033] The main function of ashing is to plate a zinc-nickel alloy layer on the surface of the copper foil, thereby improving the high-temperature oxidation resistance and enhancing the heat resistance of the copper foil. This application provides a specially formulated heat-resistant layer process that further reduces the heat loss rate of the high-temperature peel strength of the electrolytic copper foil, ensuring that the heat loss rate of the high-temperature peel strength can be controlled within 10% under the customer-required testing methods.

[0034] Furthermore, by improving the ashing process in this embodiment, the content of potassium pyrophosphate (K4P2O7) in the ashing process can be reduced, thereby reducing the consumption of raw materials during the production process.

[0035] Furthermore, the ratio of zinc ion concentration to nickel ion concentration is 2:1. The inventors discovered through experiments that, in actual production, the copper foil exhibits the best anti-peeling effect when the ratio of zinc ion concentration to nickel ion concentration is 2:1.

[0036] In the passivation process, the temperature of the passivation bath is 20-30℃, the chromium ion concentration is 0.5-1.5g / L, the pH value is 10.0-12.0, and the influent flow rate is 5-10m³ / h. 3 / h, the optical current density is 1-10A / dm 2 The surface current density is 1-10 A / dm. 2 .

[0037] The main function of passivation is to plate a layer of chromium metal onto the surface of the electrolytic copper foil to prevent oxidation, thereby increasing the oxidation resistance of the electrolytic copper foil and extending its storage time at room temperature. Using the design in this application, the amount of chromium produced during the passivation process can also be reduced. 6+ The concentration of [material] is reduced, thereby decreasing the consumption of raw materials during the production process.

[0038] In the water washing process, namely water washing I, water washing II, water washing III and water washing IV, the water washing temperature is room temperature, which is 20-30℃; and pure water is used for water washing, and the quality of the pure water is: conductivity ≤5μs / cm, turbidity ≤2, pH=6.8-7.6, and chloride ion content ≤1ppm.

[0039] The main purpose of water washing is to clean the electrolyte adhering to the surface of the copper foil, preventing electrolyte from flowing between different plating tanks and affecting the processing effect of the copper foil in the next step of the surface treatment process.

[0040] The embodiments of this application use continuous water washing processes III and IV to ensure that there is no electrolyte or ion residue on the surface of the electrolytic copper foil, so as not to affect the yield of the finished product.

[0041] In the silane spraying process, a silane coupling agent is used for spraying, and the temperature of the silane coupling agent is 10-40℃ and the flow rate is 1-7m³ / h. 3 / h, with a content of 5‰. The main function of silane spraying is to further increase the peel strength of the copper foil.

[0042] In the drying process, the copper foil can be placed in an oven and dried at 200℃-250℃. The main purpose of drying is to remove moisture and dry and wet gases from the surface and pores of the copper foil, remove hydrogen to eliminate stress, increase the flexibility and ductility of the copper foil, and eliminate brittleness.

[0043] In the copper foil unwinding and rewinding processes, the linear speed for unwinding and rewinding is 20-40 m / min.

[0044] As can be seen from the above, the formula of the present invention is simple, the cost is low, it is suitable for actual production, and it has good market prospects.

[0045] This application will also provide a clear and complete description of the solution in conjunction with the following two specific embodiments and corresponding comparative examples.

[0046] It should be understood that the embodiments described below are only a part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention.

[0047] Example 1:

[0048] In this embodiment, a 12μm thick copper foil is used for surface treatment. Sodium tungstate and cobalt sulfate are used as additives in roughening I, roughening II, and roughening III processes. Sodium tungstate and titanium sulfate are added as additives in curing I, curing II, and curing III processes. Zn is used in the ashing process. 2+ Ni 2+ =2:1, and the actual measured process parameters for each process are shown in Table 1 below:

[0049]

[0050] Table 1

[0051] Comparative Example 1: A 12μm thick copper foil was used for surface treatment. Arsenic was used as an additive in roughening processes I, II, and III. No additives were added in curing processes I, II, and III. Zn was used in the ashing process. 2+ Ni 2+ =3:1, and the actual measured process parameters for each process are shown in Table 2 below:

[0052]

[0053]

[0054] Table 2

[0055] Comparative Example 2: A 12μm thick copper foil was used for surface treatment. Sodium tungstate and cobalt sulfate were used as additives in roughening I, roughening II, and roughening III processes. Sodium tungstate and titanium sulfate were added as additives in curing I, curing II, and curing III processes. Zn was added in the ashing process. 2+ Ni 2+ =1:1, the actual measured process parameters for each process are shown in Table 3 below:

[0056]

[0057]

[0058] Table 3

[0059] Comparative Example 3: A 12μm thick copper foil was used for surface treatment. Sodium tungstate and cobalt sulfate were used as additives in roughening I, roughening II, and roughening III processes. Sodium tungstate and titanium sulfate were added as additives in curing I, curing II, and curing III processes. Zn was added in the ashing process. 2+ Ni 2+ =3:1, and the actual measured process parameters for each process are shown in Table 4 below:

[0060]

[0061]

[0062] Table 4

[0063] Example 2:

[0064] In this embodiment, a 35μm thick copper foil is used for surface treatment. Sodium tungstate and cobalt sulfate are used as additives in roughening I, roughening II, and roughening III processes. Sodium tungstate and titanium sulfate are added as additives in curing I, curing II, and curing III processes. Zn is used in the ashing process. 2+ Ni 2+ =2:1, and the actual measured process parameters for each process are shown in Table 5 below:

[0065]

[0066]

[0067] Table 5

[0068] Comparative Example 4: A 35μm thick copper foil was used for surface treatment. Arsenic was used as an additive in roughening processes I, II, and III. No additives were added in curing processes I, II, and III. Zn was used in the ashing process. 2+ Ni 2+=3:1, and the actual measured process parameters for each process are shown in Table 6 below:

[0069]

[0070]

[0071] Table 6

[0072] Comparative Example 5: A 35μm thick copper foil was used for surface treatment. Sodium tungstate and cobalt sulfate were used as additives in roughening I, roughening II, and roughening III processes. Sodium tungstate and titanium sulfate were added as additives in curing I, curing II, and curing III processes. Zn was added in the ashing process. 2+ Ni 2+ =1:1, the actual measured process parameters for each process are shown in Table 7 below:

[0073]

[0074]

[0075] Table 7

[0076] Comparative Example 6: A 35μm thick copper foil was used for surface treatment. Sodium tungstate and cobalt sulfate were used as additives in roughening I, roughening II, and roughening III processes. Sodium tungstate and titanium sulfate were added as additives in curing I, curing II, and curing III processes. Zn was added in the ashing process. 2+ Ni 2+ =3:1, and the actual measured process parameters for each process are shown in Table 8 below:

[0077]

[0078]

[0079] Table 8

[0080] The peel strength before and after thermal shock of the copper foils prepared in Example 1 and Comparative Examples 1-3, as well as Example 2 and Comparative Examples 4-6, were tested according to the method specified in Clause 7.3 of GB / T 29847-2013, and the heat loss rate of the peel strength was calculated. The test results are shown in Table 9 below:

[0081]

[0082] Table 9

[0083] As shown in Table 9 above, comparing the peel strength attenuation rate before and after thermal shock of Example 1 and Comparative Examples 1-3, the peel strength attenuation rate of Example 1 is lower than that of Comparative Examples 1-3, and the peel strength heat loss rate can be controlled within 5%.

[0084] As shown in Table 9 above, comparing the peel strength attenuation rate before and after thermal shock of Example 2 and Comparative Examples 4-6, the peel strength attenuation rate of Example 2 is lower than that of Comparative Examples 4-6, and the peel strength heat loss rate can be controlled within 5%.

[0085] According to the test method provided by the customer (testing the peel strength after baking at 200℃ for 5 hours after normal pressing of copper foil), the peel strength of copper foils prepared in Example 1 and Comparative Examples 1-3, as well as Example 2 and Comparative Examples 4-6, was tested before and after baking after pressing, and the loss rate of peel strength was calculated. The test results are shown in Table 10 below:

[0086]

[0087] Table 10

[0088] As shown in Table 10 above, when comparing the peel strength attenuation rate of Example 1 with that of Comparative Examples 1-3 using the customer-required method test, the peel strength attenuation rate of Example 1 is much lower than that of Comparative Examples 1-3, and the peel strength heat loss rate can be controlled within 10%.

[0089] As shown in Table 10 above, when comparing the peel strength attenuation rate of Example 2 with that of Comparative Examples 4-6 using the customer-required method test, the peel strength attenuation rate of Example 2 is much lower than that of Comparative Examples 4-6, and the peel strength heat loss rate can be controlled within 10%.

[0090] Therefore, by adopting the technical solution of this application, sodium tungstate and cobalt sulfate are selected as additives in the roughening process, sodium tungstate and titanium sulfate are added as additives in the curing process, and the Zn content in the ashing process is controlled. 2+ Ni 2+ The ratio of 2:1 effectively reduces the heat loss rate of peel strength. Whether tested according to the method specified in Clause 7.3 of GB / T 29847-2013, or according to the test method provided by the customer, the test results meet production requirements. Furthermore, the heat loss rate of peel strength for copper foil produced using the surface treatment process of this application can be controlled within 10%.

[0091] This application also discloses an electrolytic copper foil, which is prepared using the electrolytic copper foil surface treatment process described above. One side of the electrolytic copper foil is smooth, and the other side is rough. The electrolytic copper foil can be a reverse copper foil, or it can be other types of copper foil.

[0092] Furthermore, the inventive concept of this application can form many embodiments, but due to the limited space of the application documents, they cannot all be listed. Therefore, without conflict, the embodiments described above or the technical features can be arbitrarily combined to form new embodiments. After the embodiments or technical features are combined, the original technical effect will be enhanced.

[0093] The above description, in conjunction with specific optional embodiments, provides a further detailed explanation of this application and should not be construed as limiting the specific implementation of this application to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of this application, and all such modifications or substitutions should be considered within the scope of protection of this application.

Claims

1. A surface treatment process for electrolytic copper foil, characterized in that, The electrolytic copper foil undergoes the following processes in sequence: unwinding, pickling, roughening I, curing I, roughening II, curing II, roughening III, curing III, water washing I, ashing, water washing II, passivation, water washing III, water washing IV, silane spraying, drying, and copper foil winding. The process conditions for roughening I, roughening II, and roughening III are as follows: the temperature of the roughening bath is 20-30℃, the copper ion concentration is 9-15 g / L, the sulfuric acid concentration is 150-190 g / L, the sodium tungstate concentration is 10-60 ppm, the cobalt sulfate concentration is 5-45 ppm, and the influent flow rate is 5-10 m³ / h. 3 / h, inlet current density is 10-50A / dm 2 The current density at the liquid outlet is 5-30 A / dm³. 2 In the roughening I, roughening II, and roughening III processes, sodium tungstate and cobalt sulfate are used as electroplating additives. The process conditions for Curing I, Curing II, and Curing III are as follows: the temperature of the curing bath is 35-50℃, the copper ion concentration is 40-60 g / L, the sulfuric acid concentration is 90-120 g / L, the sodium tungstate concentration is 10-60 ppm, the titanium sulfate concentration is 0.1-3 g / L, and the inlet flow rate is 5-10 m³ / h. 3 / h, inlet current density is 10-30A / dm 2 The current density at the liquid outlet is 10-30 A / dm³. 2 In the curing I, curing II, and curing III processes, sodium tungstate and titanium sulfate are used as electroplating additives. The ashing process conditions are as follows: the temperature of the ashing bath is 30-40℃, the zinc ion concentration is 2.0-4.0 g / L, the nickel ion concentration is 1.0-2.0 g / L, the potassium pyrophosphate concentration is 40-60 g / L, the pH value is 9.0-11.0, and the influent flow rate is 5-10 m³ / h. 3 / h, the optical current density is 1-10A / dm 2 The surface current density is 1-10 A / dm. 2 In the ashing process, the ratio of zinc ion concentration to nickel ion concentration is 2:

1.

2. The electrolytic copper foil surface treatment process as described in claim 1, characterized in that, The passivation process conditions are as follows: the temperature of the passivation bath is 20-30℃, the chromium ion concentration is 0.5-1.5g / L, the pH value is 10.0-12.0, and the influent flow rate is 5-10m³ / h. 3 / h, the optical current density is 1-10A / dm 2 The surface current density is 1-10 A / dm. 2 .

3. The electrolytic copper foil surface treatment process as described in claim 1, characterized in that, In the washing processes I, II, III, and IV, the washing temperature is 20-25℃, pure water is used for washing, and the pure water quality is: conductivity ≤5μs / cm, turbidity ≤2, pH=6.8-7.6, and chloride ion content ≤1ppm.

4. The electrolytic copper foil surface treatment process as described in claim 1, characterized in that, In the silane spraying process, a silane coupling agent is used for spraying, and the temperature of the silane coupling agent is 10-40℃ and the flow rate is 1-7m³. 3 / h, content is 5‰.

5. The electrolytic copper foil surface treatment process as described in claim 1, characterized in that, In the copper foil unwinding and rewinding processes, the linear speed of unwinding and rewinding is 20-40 m / min.

6. The electrolytic copper foil surface treatment process as described in claim 1, characterized in that, In the pickling process, the temperature is 20-30℃, the copper ion concentration is 9-15g / L, and the sulfuric acid concentration is 150-190g / L.

7. An electrolytic copper foil, characterized in that, It is prepared by the electrolytic copper foil surface treatment process as described in any one of claims 1-6.

8. The electrolytic copper foil as described in claim 7, characterized in that, The electrolytic copper foil includes reverse copper foil.

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