Production process of ultra-thin high-performance copper foil

Abstract

The invention discloses a production process of an ultra-thin high-performance copper foil, which comprises the following steps: firstly, preparing a base material, selecting polyethylene glycol terephthalate or polypropylene as a polymer base material, controlling the thickness to be 2-4 microns, and forming a hydroxyl chemical bond through a biaxial stretching synchronous process to improve the interface bonding force with a copper layer; and then vacuum coating is carried out, a nano-scale copper layer with the thickness of 15-80 nm is deposited on the surface of the macromolecule base film through a magnetron sputtering or vacuum evaporation technology, and a conductive base layer is formed. The large-scale production advantage of the traditional electrolytic copper foil is combined with the fine processing capability of the calendaring process. Compared with a single electrolysis or calendering process, the composite route reduces pollution to high-purity materials and reduces influence on performance. The tensile strength and the elongation of the copper foil produced by the process are improved. Meanwhile, directional optimization of key performance such as conductivity and ductility is achieved, and the method is particularly suitable for high-end fields such as flexible circuit boards and solid-state battery current collectors.

Description

Technical Field

[0001] The present invention relates to the technical field of copper foil production, and specifically to a production process for extremely thin high-performance copper foil. Background Art

[0002] An extremely thin high-performance copper foil is an ultra-thin metal foil with a thickness generally ranging from 3 to 8 μm. Through advanced processes, it achieves high electrical conductivity, high strength, and excellent surface flatness, and is a key material for modern electronic devices and new energy batteries.

[0003] The extremely thin high-performance copper foil is widely used in high-end electronic products such as integrated circuit (IC) packaging, chip packaging substrates, and high-density interconnect (HDI) boards. The copper foil needs to have high precision, flatness, ductility, and heat resistance to ensure stability under high temperature and pressure; in lithium-ion batteries, the extremely thin copper foil serves as the negative electrode current collector, which can significantly improve the energy density of the battery. Its application scope includes fields such as power batteries for new energy vehicles, energy storage devices, and electronic products.

[0004] Traditional production of extremely thin high-performance copper foil generally uses a single electrolysis or rolling process; However, when using a single electrolysis method to produce extremely thin high-performance copper foil, micro-defects such as pinholes and pockmarks are likely to occur, resulting in fluctuations in the electrical conductivity of the copper foil and a decrease in mechanical strength, affecting the reliability of extremely thin copper foil below 5 μm; and uneven distribution of the surface current density on the cathode roller (±5% error) will cause the thickness deviation of the copper foil to exceed ±0.2 μm, affecting the high-frequency signal transmission performance of electronic circuits.

[0005] While a single physical rolling process is sensitive to the initial thickness of the copper ingot, the thickness fluctuation of 3-μm copper foil reaches ±0.5 μm, which cannot meet the strict requirements for uniformity (error < 0.1 μm) of the current collector for lithium batteries. And the difference in the thermal expansion coefficient of the rollers (>1×10⁻ 6 / °C) is likely to cause lateral thickness deviation of the copper foil, exacerbating the problem of uneven circuit in the subsequent etching process. At the same time, the material utilization rate is relatively low, the edge loss of the copper ingot during the rolling process accounts for 8-12%, and the finished product rate of ultra-thin copper foil is less than 60%, far lower than the 95% level of the composite process.

[0006] Therefore, a production process for extremely thin high-performance copper foil is proposed to solve this problem. Summary of the Invention

[0007] The purpose of the present invention is to provide a production process for extremely thin high-performance copper foil, which uses a composite process to process the extremely thin high-performance copper foil, solves the problems of processing copper foil by the existing single electrolysis or rolling process, and the tensile strength and elongation rate of the copper foil produced by this process are both improved.

[0008] To achieve the above object, the present invention provides the following technical solution: A production process for an extremely thin and high-performance copper foil, comprising the following steps: Step 1: Substrate preparation: First, select polyethylene terephthalate or polypropylene as the polymer substrate, with a thickness controlled at 2-4 μm, and form hydroxyl chemical bonds through a biaxial stretching synchronous process to enhance the interfacial bonding force with the copper layer; Step 2: Vacuum coating: Then, use magnetron sputtering or vacuum evaporation process to deposit a nano-scale copper layer with a thickness of 15-80 nm on the surface of the polymer base film to form a conductive base layer; Step 3: Electrolytic deposition: Subsequently, adopt a wet electrolysis process to prepare a high-purity and pollution-free electrolytic copper foil that meets the rolling conditions; Step 4: Copper foil rolling: Then, perform rolling processing on the initial product to roll the material thickness to 1-25 microns; Step 5: Degreasing and cleaning: Then, use an alkaline or neutral degreaser to remove the oil and contaminants on the surface of the copper foil by soaking, brushing, or spraying, adapting to the chemical resistance requirements of the polymer base film to avoid damaging the ultra-thin copper layer; at the same time, use ultrasonic assistance cleaning with a frequency of 40-80 kHz to remove sub-micron particles; Step 6: Annealing treatment: Then, keep it at 200-300 °C for 10-15 minutes to eliminate the lattice distortion generated by electrolytic deposition; High-temperature section: Heat up to 400-450 °C (±0.5 °C accuracy) and continue for 5-8 minutes to promote the recrystallization of nano-grains of 50-200 nm, and increase the tensile strength to ≥600 MPa; Step 7: Slitting and packaging: Finally, slit the produced copper foil and store it in the warehouse after passing the inspection; The size of the slit copper foil is adjusted according to actual production needs.

[0009] Preferably, in step 1, the molecular glue technology is adopted to achieve a peel strength of 30 N / 15 mm between the copper foil and the base film through surface hydroxyl activation.

[0010] Preferably, in step 3, the thickness of the electrolytic copper foil covers 6-200 microns, and the width is greater than 1380 mm.

[0011] Preferably, in step 3, by optimizing the formula of the electrolyte (containing 65-80 g / L of copper sulfate and 80-120 g / L of sulfuric acid) and the current density (2000-4000 A / m²), further electroplate to a thickness of 1 μm on the vacuum coating layer to achieve continuous and stable growth of the copper layer.

[0012] Preferably, in step 3, by introducing nano-grain control technology, the grain size of the copper foil reaches 50-200 nm, and the surface roughness Ra < 0.3 μm, improving the conductivity and mechanical strength.

[0013] Preferably, in step 4, at a high temperature of 450°C, a precision temperature control heating roller with ±0.5°C and a pressure-speed linkage algorithm are used to laminate the copper foil and the polymer base film; and through the interface chemical bonding technology, the uniformity error of the bonding between the copper layer and the base film is ensured to be <0.1μm.

[0014] Preferably, in step 5, after degreasing, it is necessary to wash with water more than twice to ensure that the residual degreaser concentration is lower than 10ppm to prevent contamination of subsequent processes.

[0015] Preferably, in step 5, in the fine washing stage, deionized water with a resistivity ≥18MΩ·cm is used for rinsing to reduce the residual metal ions; for the composite copper foil, a plasma cleaning technology under nitrogen protection is introduced to improve the interface cleanliness and inhibit oxidation.

[0016] Preferably, in step 6, a hydrogen / nitrogen mixture is used, in which the proportion of H2 is 3-5%, to reduce the oxide layer on the surface of the copper foil and avoid thermal decomposition of the polymer base film.

[0017] Preferably, in step 6, by combining the tension closed-loop control technology, the fluctuation of the elongation rate of the copper foil during the annealing process is controlled within ±0.3% to ensure that there are no wrinkling defects in the ultra-thin copper foil.

[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention patent combines the large-scale production advantages of traditional electrolytic copper foil with the fine processing ability of the rolling process. Compared with a single electrolytic or rolling process, this composite route reduces the pollution of high-purity materials and reduces the impact on performance. The copper foil produced by this process has improved tensile strength and elongation rate. At the same time, the directional optimization of key properties such as conductivity and ductility is achieved to meet different usage conditions. The comprehensive production cost is reduced and the yield rate is increased, which is especially suitable for high-end fields such as flexible circuit boards and solid-state battery current collectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the production process of the ultra-thin high-performance copper foil of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention will be described in more detail by way of examples below. These examples are merely illustrative and do not limit the scope of the present invention in any way.

[0021] The present invention provides a technical solution: a production process of an ultra-thin high-performance copper foil, including the following steps: Step 1: Substrate Preparation: First, select polyethylene terephthalate or polypropylene as the polymer substrate with a thickness controlled at 2 - 4 μm, and form hydroxyl chemical bonds through a biaxial stretching synchronous process to enhance the interfacial bonding force with the copper layer; Step 2: Vacuum Coating: Then, use magnetron sputtering or vacuum evaporation process to deposit a nano - scale copper layer with a thickness of 15 - 80 nm on the surface of the polymer base film to form a conductive base layer; Step 3: Electrolytic Deposition: Subsequently, adopt a wet electrolysis process to prepare high - purity and pollution - free electrolytic copper foil that meets the rolling conditions; Step 4: Copper Foil Rolling: Then, perform rolling processing on the initial product to roll the material thickness to 1 - 25 microns; Step 5: Degreasing and Cleaning: Then, use an alkaline or neutral degreaser to remove the oil and contaminants on the surface of the copper foil by soaking, brushing, or spraying, adapting to the chemical resistance requirements of the polymer base film and avoiding damage to the ultra - thin copper layer; at the same time, use ultrasonic cleaning with a frequency of 40 - 80 kHz to remove sub - micron - sized particles; Step 6: Annealing Treatment: Then, keep it at 200 - 300 °C for 10 - 15 minutes to eliminate the lattice distortion caused by electrolytic deposition; High - temperature stage: Heat up to 400 - 450 °C (±0.5 °C accuracy) and continue for 5 - 8 minutes to promote the recrystallization of nano - grains of 50 - 200 nm, and increase the tensile strength to ≥600 MPa; Step 7: Slitting and Packaging: Finally, slit the produced copper foil and store it in the warehouse after passing the inspection; The size of the copper foil slitting is adjusted according to the actual production needs.

[0022] Example 1: First, prepare the substrate. Select polyethylene terephthalate or polypropylene as the polymer substrate, with a thickness controlled at 2 - 4 μm, and form hydroxyl chemical bonds through a biaxial stretching synchronous process to enhance the interfacial bonding force with the copper layer. Then, perform vacuum coating. Use magnetron sputtering or vacuum evaporation technology to deposit a nanoscale copper layer with a thickness of 15 - 80 nm on the surface of the polymer base film to form a conductive base layer. Subsequently, perform electrolytic deposition. Use a wet electrolytic process to prepare high-purity and pollution-free electrolytic copper foil that meets the rolling conditions. After that, perform copper foil rolling. Roll the initial product to reduce the material thickness to 1 - 25 microns. Then, perform degreasing and cleaning. Use immersion, brushing, or spraying methods, and use alkaline or neutral degreasing agents to remove oil and contaminants on the surface of the copper foil, adapting to the chemical resistance requirements of the polymer base film to avoid damaging the ultra-thin copper layer. At the same time, use ultrasonic assistance cleaning with a frequency of 40 - 80 kHz to remove sub-micron particles. Then, perform annealing treatment. Keep the temperature at 200 - 300 °C for 10 - 15 minutes to eliminate the lattice distortion generated by electrolytic deposition. High-temperature section: Heat up to 400 - 450 °C (±0.5 °C accuracy) and maintain for 5 - 8 minutes to promote the recrystallization of nano-crystals with a size of 50 - 200 nm, and increase the tensile strength to ≥600 MPa. Finally, perform slitting and packaging. Slit the produced copper foil and store it in the warehouse after passing the inspection. The size of the copper foil slitting is adjusted according to actual production needs.

[0023] Example 2: In Example 1, add the following processes: In step 1, use the molecular glue technology to achieve a peel strength of 30 N / 15 mm between the copper foil and the base film through surface hydroxyl activation.

[0024] In step 3, the thickness of the electrolytic copper foil covers 6 - 200 microns, and the width is greater than 1380 mm. By optimizing the formula of the electrolyte (containing 65 - 80 g / L of copper sulfate and 80 - 120 g / L of sulfuric acid) and the current density (2000 - 4000 A / m²), further electroplate to a thickness of 1 μm on the vacuum coating layer to achieve continuous and stable growth of the copper layer. By introducing nano-crystal grain control technology, the grain size of the copper foil reaches 50 - 200 nm, and the surface roughness Ra < 0.3 μm, improving the conductivity and mechanical strength.

[0025] First, prepare the substrate. Select polyethylene terephthalate or polypropylene as the polymer substrate, with a thickness controlled at 2 - 4 μm, and form hydroxyl chemical bonds through a biaxial stretching synchronous process to enhance the interfacial bonding force with the copper layer; adopt the molecular glue technology to achieve a peel strength of 30 N / 15 mm between the copper foil and the base film through surface hydroxyl activation. Then, perform vacuum coating. Use magnetron sputtering or vacuum evaporation process to deposit a nano-scale copper layer with a thickness of 15 - 80 nm on the surface of the polymer base film to form a conductive base layer; subsequently, perform electrolytic deposition. Use a wet electrolytic process to prepare high-purity and pollution-free electrolytic copper foil that meets the rolling conditions; the thickness of the electrolytic copper foil covers 6 - 200 microns, and the width is greater than 1380 mm; by optimizing the formula of the electrolyte (containing 65 - 80 g / L of copper sulfate and 80 - 120 g / L of sulfuric acid) and the current density (2000 - 4000 A / m²), further electroplate to a thickness of 1 μm on the vacuum coating layer to achieve continuous and stable growth of the copper layer; by introducing nano-grain control technology, make the grain size of the copper foil reach 50 - 200 nm, and the surface roughness Ra < 0.3 μm to improve conductivity and mechanical strength. After that, perform copper foil rolling. Roll the initial product to reduce the material thickness to 1 - 25 microns; then perform degreasing and cleaning. Use immersion, brushing or spraying methods, and use alkaline or neutral degreasing agents to remove oil and contaminants on the surface of the copper foil, adapt to the chemical resistance requirements of the polymer base film, and avoid damaging the ultra-thin copper layer; at the same time, use ultrasonic cleaning with a frequency of 40 - 80 kHz to remove sub-micron particles; then perform annealing treatment. Keep it at 200 - 300 °C for 10 - 15 minutes to eliminate the lattice distortion generated by electrolytic deposition; High-temperature section: Heat up to 400 - 450 °C (±0.5 °C accuracy) and continue for 5 - 8 minutes to promote the recrystallization of nano-grains of 50 - 200 nm and increase the tensile strength to ≥600 MPa; finally, perform slitting and packaging. Slit the produced copper foil and store it in the warehouse after passing the inspection; the size of the slit copper foil is adjusted according to actual production needs.

[0026] Example Three: In Example Two, add the following processes: In step 4, at a high temperature of 450 °C, use a precision temperature control heating roller with ±0.5 °C and a pressure-speed linkage algorithm to laminate the copper foil and the polymer base film; and through the interfacial chemical bonding technology, ensure that the uniformity error of the bonding between the copper layer and the base film is < 0.1 μm.

[0027] In step 5, after degreasing, perform more than two water washes to ensure that the residual degreasing agent concentration is lower than 10 ppm to prevent pollution in subsequent processes; in the fine washing stage, rinse with deionized water with a resistivity ≥ 18 MΩ·cm to reduce metal ion residues; introduce plasma cleaning technology under nitrogen protection for the composite copper foil to improve the interfacial cleanliness and inhibit oxidation.

[0028] First, prepare the substrate. Select polyethylene terephthalate or polypropylene as the polymer substrate, with a thickness controlled at 2 - 4 μm, and form hydroxyl chemical bonds through a biaxial stretching synchronous process to enhance the interfacial bonding force with the copper layer; adopt the molecular glue technology to achieve a peel strength of 30 N / 15 mm between the copper foil and the base film through surface hydroxyl activation. Then, perform vacuum coating. Use magnetron sputtering or vacuum evaporation technology to deposit a nano-scale copper layer with a thickness of 15 - 80 nm on the surface of the polymer base film to form a conductive base layer; subsequently, perform electrolytic deposition. Use a wet electrolytic process to prepare high-purity and pollution-free electrolytic copper foil that meets the rolling conditions; the thickness of the electrolytic copper foil covers 6 - 200 microns, and the width is greater than 1380 mm; by optimizing the formula of the electrolyte (containing 65 - 80 g / L of copper sulfate and 80 - 120 g / L of sulfuric acid) and the current density (2000 - 4000 A / m²), further electroplate to a thickness of 1 μm on the vacuum coating layer to achieve continuous and stable growth of the copper layer; by introducing nano-grain control technology, make the grain size of the copper foil reach 50 - 200 nm, and the surface roughness Ra < 0.3 μm to improve conductivity and mechanical strength. After that, perform copper foil rolling. Roll the initial product to reduce the material thickness to 1 - 25 microns; at a high temperature of 450 °C, use a precision temperature control heating roller with ±0.5 °C and a pressure-speed linkage algorithm to compound the copper foil with the polymer base film; and through the interfacial chemical bonding technology, ensure that the uniformity error of the bonding between the copper layer and the base film is < 0.1 μm. Then, perform degreasing and cleaning. Use immersion, brushing, or spraying methods, and use alkaline or neutral degreasing agents to remove oil and contaminants on the surface of the copper foil, adapting to the chemical resistance requirements of the polymer base film to avoid damaging the ultra-thin copper layer; at the same time, use ultrasonic assisted cleaning with a frequency of 40 - 80 kHz to remove sub-micron particles; after degreasing, perform more than two water washes to ensure that the residual degreasing agent concentration is lower than 10 ppm to prevent contamination of subsequent processes; in the fine washing stage, rinse with deionized water with a resistivity ≥ 18 MΩ·cm to reduce metal ion residues; for composite copper foils, introduce a plasma cleaning technology under nitrogen protection to improve the interfacial cleanliness and inhibit oxidation; then, perform annealing treatment. Keep it at 200 - 300 °C for 10 - 15 minutes to eliminate the lattice distortion generated by electrolytic deposition; in the high-temperature section: heat up to 400 - 450 °C (±0.5 °C accuracy) and hold for 5 - 8 minutes to promote the recrystallization of nano-grains of 50 - 200 nm, and increase the tensile strength to ≥ 600 MPa; finally, perform slitting and packaging. Slit the produced copper foil and store it in the warehouse after passing the inspection; the size of the copper foil slitting is adjusted according to actual production needs.

[0029] Example 4: In Example 3, add the following processes: In step 6, a hydrogen / nitrogen mixture gas is used, in which the proportion of H2 is 3-5%, to reduce the oxide layer on the surface of the copper foil and avoid the thermal decomposition of the polymer base film; by combining the tension closed-loop control technology, the fluctuation of the elongation rate of the copper foil during the annealing process is controlled within ±0.3%, ensuring that the ultra-thin copper foil has no wrinkle defects.

[0030] First, prepare the substrate. Select polyethylene terephthalate or polypropylene as the polymer substrate, with a thickness controlled within 2 - 4 μm, and form hydroxyl chemical bonds through a biaxial stretching synchronous process to enhance the interfacial bonding force with the copper layer; adopt the molecular glue technology to achieve a peel strength of 30 N / 15 mm between the copper foil and the base film through surface hydroxyl activation. Then, perform vacuum coating. Use magnetron sputtering or vacuum evaporation process to deposit a nano-scale copper layer with a thickness of 15 - 80 nm on the surface of the polymer base film to form a conductive base layer; subsequently, perform electrolytic deposition. Use a wet electrolysis process to prepare high-purity and pollution-free electrolytic copper foil that meets the rolling conditions; the thickness of the electrolytic copper foil covers 6 - 200 microns, and the width is greater than 1380 mm; by optimizing the formula of the electrolyte (containing 65 - 80 g / L of copper sulfate and 80 - 120 g / L of sulfuric acid) and the current density (2000 - 4000 A / m²), electroplate further to a thickness of 1 μm on the vacuum coating layer to achieve continuous and stable growth of the copper layer; by introducing nano-grain control technology, the grain size of the copper foil reaches 50 - 200 nm, and the surface roughness Ra < 0.3 μm, improving the conductivity and mechanical strength. After that, perform copper foil rolling. Roll the initial product to reduce the material thickness to 1 - 25 microns; at a high temperature of 450 °C, use a precision temperature control heating roller with ±0.5 °C and a pressure-speed linkage algorithm to compound the copper foil with the polymer base film; and through the interfacial chemical bonding technology, ensure that the uniformity error of the bonding between the copper layer and the base film is < 0.1 μm. Then, perform degreasing and cleaning. Adopt immersion, brushing or spraying methods, and use alkaline or neutral degreasing agents to remove the oil and contaminants on the surface of the copper foil, adapting to the chemical resistance requirements of the polymer base film to avoid damaging the ultra-thin copper layer; at the same time, use ultrasonic assisted cleaning with a frequency of 40 - 80 kHz to remove sub-micron particles; after degreasing, perform more than two water washes to ensure that the residual degreasing agent concentration is lower than 10 ppm to prevent pollution in subsequent processes; in the fine washing stage, rinse with deionized water with a resistivity ≥ 18 MΩ·cm to reduce metal ion residues; for composite copper foils, introduce a plasma cleaning technology under nitrogen protection to improve the interfacial cleanliness and inhibit oxidation. Then, perform annealing treatment. Keep it at 200 - 300 °C for 10 - 15 minutes to eliminate the lattice distortion generated by electrolytic deposition; in the high-temperature section: heat up to 400 - 450 °C (±0.5 °C accuracy) and keep it for 5 - 8 minutes to promote the recrystallization of nano-grains of 50 - 200 nm, increasing the tensile strength to ≥ 600 MPa; use a hydrogen / nitrogen mixed gas, with the proportion of H2 being 3 - 5%, to reduce the oxide layer on the surface of the copper foil and avoid thermal decomposition of the polymer base film; by combining the tension closed-loop control technology, the elongation fluctuation of the copper foil during the annealing process is controlled within ±0.3%, ensuring that the ultra-thin copper foil has no wrinkle defects. Finally, perform slitting and packaging. Slit the produced copper foil and store it in the warehouse after passing the inspection; the size of the slit copper foil is adjusted according to actual production needs.

[0031] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A production process for an extremely thin and high-performance copper foil, characterized in that: It includes the following steps: Step 1: Substrate preparation: First, select polyethylene terephthalate or polypropylene as the polymer substrate, with a thickness controlled at 2 - 4 μm, and form hydroxyl chemical bonds through a biaxial stretching synchronous process to enhance the interfacial bonding force with the copper layer; Step 2: Vacuum coating: Then, use magnetron sputtering or vacuum evaporation process to deposit a nanoscale copper layer with a thickness of 15 - 80 nm on the surface of the polymer base film to form a conductive base layer; Step 3: Electrolytic deposition: Subsequently, adopt a wet electrolysis process to prepare high-purity and pollution-free electrolytic copper foil that meets the rolling conditions; Step 4: Copper foil rolling: Then, perform rolling processing on the initial product to roll the material thickness to 1 - 25 microns; Step 5: Degreasing and cleaning: Then, use alkaline or neutral degreasing agents to remove the oil and contaminants on the copper foil surface by soaking, brushing, or spraying, adapting to the chemical resistance requirements of the polymer base film to avoid damaging the ultra-thin copper layer; at the same time, use ultrasonic cleaning with a frequency of 40 - 80 kHz to remove sub-micron particles; Step 6: Annealing treatment: Then, keep it at 200 - 300 °C for 10 - 15 minutes to eliminate the lattice distortion generated by electrolytic deposition; High-temperature section: Heat up to 400 - 450 °C (±0.5 °C accuracy) and continue for 5 - 8 minutes to promote the recrystallization of nano-crystals of 50 - 200 nm, and increase the tensile strength to ≥600 MPa; Step 7: Slitting and packaging: Finally, slit the produced copper foil and store it in the warehouse after passing the inspection; The size of the slit copper foil is adjusted according to actual production needs.

2. The production process of an extremely thin and high-performance copper foil according to claim 1, characterized in that: In step 1, the peel strength between the copper foil and the base film reaches 30 N / 15 mm through surface hydroxyl activation using molecular glue technology.

3. The production process of an extremely thin and high-performance copper foil according to claim 1, characterized in that: In step 3, the thickness of the electrolytic copper foil covers 6 - 200 microns, and the width is greater than 1380 mm.

4. The production process of an extremely thin and high-performance copper foil according to claim 1, characterized in that: In step 3, by optimizing the formula of the electrolyte (containing 65 - 80 g / L of copper sulfate and 80 - 120 g / L of sulfuric acid) and the current density (2000 - 4000 A / m²), further electroplate to a thickness of 1 μm on the vacuum coating layer to achieve continuous and stable growth of the copper layer.

5. The production process of an extremely thin and high-performance copper foil according to claim 1, characterized in that: In step 3, by introducing nano-crystal grain control technology, the grain size of the copper foil reaches 50 - 200 nm, and the surface roughness Ra < 0.3 μm, improving the conductivity and mechanical strength.

6. The production process of an extremely thin and high-performance copper foil according to claim 1, characterized in that: In step 4, at a high temperature of 450 °C, use a precision temperature control heating roller with ±0.5 °C and a pressure-speed linkage algorithm to compound the copper foil with the polymer base film; and through interface chemical bonding technology, ensure that the uniformity error of the bonding between the copper layer and the base film is < 0.1 μm.

7. The production process of an extremely thin and high-performance copper foil according to claim 1, characterized in that: In step 5, after degreasing, it needs to be washed more than twice to ensure that the residual degreasing agent concentration is lower than 10 ppm to prevent pollution in subsequent processes.

8. The production process of an ultra-thin high-performance copper foil according to claim 1, characterized in that: In step 5, in the fine washing stage, use deionized water with a resistivity ≥18 MΩ·cm to rinse, reducing the residual metal ions; for composite copper foil, introduce plasma cleaning technology under nitrogen protection to improve the interface cleanliness and inhibit oxidation.

9. The production process of an ultra-thin and high-performance copper foil according to claim 1, characterized in that: In step 6, use a hydrogen / nitrogen mixture, in which the proportion of H2 is 3 - 5%, to reduce the oxide layer on the surface of the copper foil and avoid thermal decomposition of the polymer base film.

10. The production process of an extremely thin and high-performance copper foil according to claim 1, characterized in that: In step 6, by combining the tension closed-loop control technology, the fluctuation of the copper foil elongation rate during the annealing process is controlled within ±0.3%, ensuring that the ultra-thin copper foil has no wrinkle defects.

Images