Preparation method of electronic circuit copper foil

Abstract

The invention belongs to the technical field of new material preparation, and discloses a preparation method of an electronic circuit copper foil. Cathode copper is used as a raw material, after an oxide layer is removed through acid pickling, the cathode copper reacts with dilute sulphuric acid to generate a copper sulfate solution, a high-purity electrolyte is obtained through precise filtration, an electrolysis system with a titanium-based DSA anode and a mirror polishing titanium roller cathode is adopted, and the titanium-based DSA / mirror polishing titanium roller is obtained by regulating and controlling electrolyte components (high / low copper ion concentration), the flow velocity, the temperature and a power supply mode in a staged mode. Gradient deposition of a nanocrystalline bottom layer, a transition layer and a compact surface layer is achieved in sequence, and finally a raw foil product with the controllable surface roughness is obtained through continuous stripping, cleaning and drying. The copper foil provided by the invention solves the technical contradiction that the roughness is reduced while the strength is reduced in the traditional copper foil, has the characteristics of high frequency, low loss and high peel strength, can be used as a core conductive material of a copper-clad plate and a printed circuit board, and provides a key material support for electronic equipment and a new energy battery.

Description

Technical Field

[0001] The present application belongs to the field of new material technology, and specifically relates to a method for preparing electronic circuit copper foil. Background Art

[0002] Electronic circuit copper foil is an ultra-thin copper material commonly used in the manufacture of printed circuit boards (PCBs). It is a thin sheet of copper with excellent electrical and thermal conductivity and flexibility. One side is rough (for bonding to the substrate) and the other side is shiny (for circuit etching). Its thickness generally ranges from a few microns to tens of microns, with common thicknesses including 7μm, 12μm, 18μm, and 35μm. The mainstream process for manufacturing electronic circuit copper foil is electrolytic copper foil: copper foil produced by electrolysis. This involves dissolving the copper raw material in an electrolyte and depositing the copper foil on the cathode through an electrolytic process. The key technology lies in controlling surface roughness (Rz value). High-frequency, high-speed PCBs require ultra-low-profile copper foil (HVLP) or reverse-phase copper foil (RTF) to reduce signal attenuation.

[0003] Conventional electrolytic copper foil faces the following challenges in electronic circuit applications: The high surface roughness of conventional copper foil leads to signal loss in high-frequency bands, making it unable to meet the requirements of 5G millimeter-wave communications. Existing roughening processes also result in uneven copper filaments, imperfect interfacial bonding, low peel strength, and easy delamination during high-temperature lamination.

[0004] Simultaneously achieving low profile (Rz≤3μm) and high peel strength (≥1.8N / mm) is a technical difficulty that urgently needs to be solved in the existing technology. Summary of the Invention

[0005] Purpose of the Invention: To address the shortcomings of the prior art, this application provides a method for preparing copper foil for electronic circuits. By precisely controlling parameters such as dissolved copper, electrolyte composition, current pattern, temperature, and flow rate, combined with the use of additives, high-performance copper foil can be produced. This application addresses the prior art's difficulty in achieving both low roughness and high peel strength, resulting in a product suitable for high-performance electronic circuit applications.

[0006] Technical solution: The method for preparing the electronic circuit copper foil provided in this application comprises the following specific steps:

[0007] Cathode copper is used as raw material, and the surface oxides are removed by pickling. Then, it is reacted with dilute sulfuric acid in a copper dissolving tank. The temperature is controlled at 70-90°C, and compressed air is introduced to oxidize and dissolve the copper material to generate copper sulfate solution. Solid impurities are removed through multi-stage filtration. After pickling to remove the surface oxides of the cathode copper, the copper dissolution is accelerated by the oxidation of dilute sulfuric acid and compressed air at 70-90°C (2Cu+O2+2H2SO4→2CuSO4+2H2O). Multi-stage filtration ensures the purity of the electrolyte to prevent impurities from affecting the deposition quality. Electrolyte 1 and electrolyte 2 are prepared separately. The Cu in electrolyte 1 is 2.347kJ / cm2. 2+ The concentration is 250±1g / L; Cu in electrolyte 2 2+ The concentration is 100±1g / L.

[0008] Electrolytic cell configuration: the anode is titanium-based and coated with iridium-tantalum oxide, and the cathode is Titanium roller (mirror polished surface, surface roughness Ra ≤ 0.1 μm), interpole distance 8-12 cm.

[0009] Add electrolyte 1 to the electrolytic cell, control the electrolyte temperature at 50±1℃ and the flow rate at 40-44m 3 / h. Turn on the cathode roller and rotate it at a constant speed of 8-10m / min. Apply DC power with a voltage of 2.3-3.1V and control the current density at 15-30A / dm 2 , copper ions are reduced and deposited on the surface of the cathode roller, the deposition time is controlled to ±1s, high concentration Cu 2+ (250g / L) combined with DC electrodeposition, through 30A / dm 2 High current density and precise temperature control (50°C) promote the rapid growth of tiny crystal nuclei, forming a 3μm nanocrystalline layer (55±3nm grains). This layer provides an excellent substrate for subsequent deposition.

[0010] Adjust the flow rate of electrolyte 1 to 30-32m 3 / h, and at the same time, electrolyte 2 is added to the electrolytic cell at a flow rate of 10-12m 3 / h, control the electrolyte temperature at 48±1℃, switch to pulse power supply, control the pulse current (on-off ratio 1:3, peak value 40A / dm 2 ), observe the oscilloscope to confirm the pulse waveform (40A peak, duty cycle 25%), deposition time 70-120s. Pulse power supply (40A / dm 2 Peak) intermittent current makes ion diffusion more uniform, and the mixed electrolyte (Cu 2+ Gradient concentration) reduces the internal stress, and the 7μm transition layer (85±5nm grains) balances the difference in mechanical properties between the nanolayer and the surface layer.

[0011] Adjust the flow rate of electrolyte 1 to 20-22m 3 / h, adjust the electrolyte flow rate to 10-12m 3 / h, control the electrolyte temperature at 40-45℃, switch the power supply to DC superimposed pulse (10A / dm 2 DC+5A / dm 2 The low temperature and combined current mode (DC + pulse) work synergistically to suppress dendrite growth and form a low-roughness surface layer of 8μm (Ra ≤ 0.8μm). This mode solves the "dog bone effect" (edge accumulation) problem that is prone to DC electroplating and achieves consistent copper thickness between the hole wall and the surface.

[0012] After the copper foil is rotated out of the liquid surface with the roller, it is washed with high-pressure water and dried with an air knife, and then continuously peeled off from the cathode roller to form the original foil.

[0013] Specifically, the configuration of the electrolytic cell is as follows: the anode is a titanium-based anode coated with iridium tantalum oxide, the cathode is a φ1500mm titanium roller, and the inter-electrode spacing is 8-12cm to ensure uniform current distribution and avoid dendrite growth caused by excessive local current density.

[0014] Specifically, the surface of the cathode titanium roller is mirror-polished, with a surface roughness of Ra≤0.1 μm, ensuring a smooth cathode surface, reducing surface defects during copper foil deposition, and improving the flatness and quality of the copper foil.

[0015] Specifically, the pulse current is controlled to have an on-off ratio of 1:3 and a current peak of 20-40A / dm 2 , observe the oscilloscope to confirm the pulse waveform.

[0016] Specifically, the DC superposition pulse controls the DC current to be 10A / dm 2 , superimposed pulse current is 5A / dm 2 .

[0017] A typical deposition condition of the present invention is: first stage: current mode: DC 30A / dm 2 (voltage 3.1±0.05V); temperature: 50±0.3℃; deposition time: 90s. Second stage: current mode: pulse power supply (peak 40A / dm 2 , frequency 1000Hz); temperature: 48±0.3℃; ultrasound assistance: 50W / cm 2 (40kHz); deposition time: 70s. Phase 3: current mode: 10A / dm 2 DC+5A / dm 2 Pulse (frequency 500 Hz); temperature: 45±0.3°C; deposition time: 40 s.

[0018] Furthermore, the electrolyte 1 also contains additives.

[0019] Specifically, the additives include one or more of hydrochloric acid, gelatin, thiourea, hydroxyethyl cellulose, collagen, sodium polydisulfide propanesulfonate, sodium 3-mercapto-1-propanesulfonate, and sodium thioalcohol propanesulfonate. Hydrochloric acid adjusts the acidity of the electrolyte, ensuring stable dissolution of copper ions. Organic additives adsorb on the copper surface, forming a protective film that reduces dendrite growth and improves the flatness of the copper foil. Sulfonate additives improve the electrolyte's conductivity, reduce internal stress, and enhance the mechanical properties of the copper foil.

[0020] Furthermore, the raw foil prepared in the present invention can be further processed to obtain a copper foil with a roughness of about 2 microns and high peel strength to meet the special needs of ultra-low profile copper foil required for high-frequency and high-speed electronic circuits.

[0021] The specific steps are: first place it in the roughening solution and ultrasonically treat it for 20 seconds; then place it in the electrolyte and use pulse current treatment for 40 seconds to control the morphology; finally, passivate it in an immersion solution at 130°C for 8 minutes.

[0022] More specifically, the roughening solution is 80 g / L H2O2 + 100 g / L H2SO4. The electrolyte is 15 g / L Na2S2O3 + 20 g / L ammonium citrate + 0.3 g / L benzimidazole. The impregnation solution is 1.8% KH-550 silane + 8% sulfur-containing polyacrylate emulsion (pH = 4.0).

[0023] Beneficial Effects: This invention achieves a gradient reduction in copper ion concentration by preparing electrolytes of varying concentrations. Simultaneously, a three-stage deposition process forms a hierarchical structure with a bottom nanocrystal layer, a middle transition layer, and a surface dense layer. This reduces matte surface roughness and high-frequency signal transmission loss, while also achieving high peel strength. Precisely coordinated control of electrolytic parameters allows for designable copper foil microstructures. A DC-pulse-DC superposition pulse system enhances crystal density, achieving both high elongation and low internal resistance.

[0024] The present invention solves the technical contradiction of traditional copper foil that "reducing roughness will inevitably reduce strength". The product obtained by the present invention has the characteristics of high frequency, low loss and high peel strength. It can be used as the core conductive material of copper clad laminates and printed circuit boards, providing key material support for electronic equipment and new energy batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the SEM electron microscope image of the copper foil obtained in Example 1.

[0026] Figure 2 This is the SEM electron microscope image of the copper foil obtained in Example 2.

[0027] Figure 3This is the SEM electron microscope image of the copper foil obtained in Example 3.

[0028] Figure 4 This is a SEM electron microscope image of commercially available conventional standard copper foil. DETAILED DESCRIPTION

[0029] The technical solution of the present application is described in detail below through examples, but the scope of protection of the present application is not limited to the examples. The parts described in the present invention are all calculated by mass.

[0030] Example 1

[0031] Cathode copper is used as raw material, and the surface oxide is removed by pickling. Then it is reacted with dilute sulfuric acid (concentration 180-220g / L) in a copper dissolving tank. The temperature is controlled at 70-90℃, and compressed air (flow rate 2m 3 / h) oxidize and dissolve the copper material to generate copper sulfate solution, and remove solid impurities through multi-stage filtration (pore size ≤ 1μm). Prepare electrolyte 1 and electrolyte 2 respectively. 2+ The concentration is 250g / L; Cu in electrolyte 2 2+ The concentration is 100g / L.

[0032] Electrolytic cell configuration: anode is titanium-based coated with iridium tantalum oxide coating (DSA anode), cathode is Titanium roller (mirror polished surface, surface roughness Ra ≤ 0.1 μm), interpole distance 8-12 cm.

[0033] Add electrolyte 1 to the electrolytic cell, control the electrolyte temperature at 50±1℃ and the flow rate at 40m 3 / h. Turn on the cathode roller and rotate it at a constant speed of 8m / min. Apply DC power with a voltage of 3.1±0.05V and a current density of 30A / dm 2 Copper ions were reduced and deposited on the surface of the cathode roller. The deposition time was controlled at 90s to form a nanocrystalline layer with a thickness of 3μm (grain size 55±3nm).

[0034] Adjust the flow rate of electrolyte 1 to 30m 3 / h, and at the same time, electrolyte 2 is added to the electrolytic cell at a flow rate of 10m 3 / h, control the electrolyte temperature at 48±1℃, switch to pulse power supply, control the pulse current (on-off ratio 1:3, peak value 40A / dm 2 ), the pulse waveform (40A peak, 25% duty cycle) was confirmed by observing the oscilloscope, the deposition time was 70s, and the thickness was 7μm (grain size 85±5nm).

[0035] Adjust the flow rate of electrolyte 1 to 20m 3 / h, adjust the electrolyte flow rate to 10m3 / h, control the electrolyte temperature at 45±1℃, switch the power supply to DC superimposed pulse (10A / dm 2 DC+5A / dm 2 pulse), deposition time 40s, and dense surface layer thickness of 8μm.

[0036] After the copper foil is rolled out of the liquid surface with the roller, it is washed with high-pressure water and dried with air knives, and then continuously peeled off from the cathode roller to form the original foil. The test results of the obtained product are shown in the following table:

[0037]

[0038]

[0039] Example 2

[0040] Cathode copper is used as raw material, and the surface oxide is removed by pickling. Then it is reacted with dilute sulfuric acid (concentration 180-220g / L) in a copper dissolving tank. The temperature is controlled at 70-90℃, and compressed air (flow rate 2m 3 / h) oxidize and dissolve the copper material to generate copper sulfate solution, and remove solid impurities through multi-stage filtration (pore size ≤ 1μm). Prepare electrolyte 1 and electrolyte 2 respectively. 2+ The concentration is 250g / L; Cu in electrolyte 2 2+ The concentration is 100g / L.

[0041] Electrolytic cell configuration: anode is titanium-based coated with iridium tantalum oxide coating (DSA anode), cathode is Titanium roller (mirror polished surface, surface roughness Ra ≤ 0.1 μm), interpole distance 8-12 cm.

[0042] Add electrolyte 1 to the electrolytic cell, control the electrolyte temperature at 50±1℃ and the flow rate at 40m 3 / h. Turn on the cathode roller and rotate it at a constant speed of 8m / min. Apply DC power with a voltage of 2.3±0.05V and control the current density at 15A / dm 2 Copper ions were reduced and deposited on the surface of the cathode roller. The deposition time was controlled at 90s to form a nanocrystalline layer with a thickness of 3μm (grain size 55±3nm).

[0043] Adjust the flow rate of electrolyte 1 to 30m 3 / h, and at the same time, electrolyte 2 is added to the electrolytic cell at a flow rate of 10m 3 / h, control the electrolyte temperature at 45±1℃, switch to pulse power supply, control the pulse current (on-off ratio 1:3, peak value 20A / dm 2 ), the pulse waveform (220A peak, 25% duty cycle) was confirmed by observing the oscilloscope, the deposition time was 120s, and the thickness was 7μm (grain size 85±5nm).

[0044] Adjust the flow rate of electrolyte 1 to 20m 3 / h, adjust the electrolyte flow rate to 10m 3 / h, control the electrolyte temperature at 40±1℃, switch the power supply to DC superimposed pulse (10A / dm 2 DC+5A / dm 2 pulse), deposition time 40s, and dense surface layer thickness of 8μm.

[0045] After the copper foil is rotated out of the liquid surface with the roller, it is washed with high-pressure water and dried with an air knife, and then continuously peeled off from the cathode roller to form the original foil.

[0046] Example 3

[0047] Cathode copper is used as raw material, and the surface oxide is removed by pickling. Then it is reacted with dilute sulfuric acid (concentration 180-220g / L) in a copper dissolving tank. The temperature is controlled at 70-90℃, and compressed air (flow rate 2m 3 / h) oxidize and dissolve the copper material to generate copper sulfate solution, and remove solid impurities through multi-stage filtration (pore size ≤ 1μm). Prepare electrolyte 1 and electrolyte 2 respectively. 2+ The concentration is 250g / L, and 5M hydrochloric acid and 0.8g / L gelatin are added; Cu in electrolyte 2 2+ The concentration is 100g / L.

[0048] Electrolytic cell configuration: anode is titanium-based coated with iridium tantalum oxide coating (DSA anode), cathode is Titanium roller (mirror polished surface, surface roughness Ra ≤ 0.1 μm), interpole distance 8-12 cm.

[0049] Add electrolyte 1 to the electrolytic cell, control the electrolyte temperature at 50±1℃ and the flow rate at 40m 3 / h. Turn on the cathode roller and rotate it at a constant speed of 8m / min. Apply DC power with a voltage of 3.1±0.05V and a current density of 30A / dm 2 Copper ions were reduced and deposited on the surface of the cathode roller. The deposition time was controlled at 90s to form a nanocrystalline layer with a thickness of 3μm (grain size 55±3nm).

[0050] Adjust the flow rate of electrolyte 1 to 30m 3 / h, and at the same time, electrolyte 2 is added to the electrolytic cell at a flow rate of 10m 3 / h, control the electrolyte temperature at 48±1℃, switch to pulse power supply, control the pulse current (on-off ratio 1:3, peak value 40A / dm 2 ), the pulse waveform (40A peak, 25% duty cycle) was confirmed by observing the oscilloscope, the deposition time was 70s, and the thickness was 7μm (grain size 85±5nm).

[0051] Adjust the flow rate of electrolyte 1 to 20m 3 / h, adjust the electrolyte flow rate to 10m 3 / h, control the electrolyte temperature at 45±1℃, switch the power supply to DC superimposed pulse (10A / dm 2 DC+5A / dm 2 pulse), deposition time 40s, and dense surface layer thickness of 8μm.

[0052] After the copper foil is rotated out of the liquid surface with the roller, it is washed with high-pressure water and dried with an air knife, and then continuously peeled off from the cathode roller to form the original foil.

[0053] The comparative data of 18μm copper foil obtained from Example 1 to Example 3 are shown in the following table. Figure 1 、 Figure 2 、 Figure 3 As shown. The commercially available standard 18μm copper foil is as follows Figure 4 shown.

[0054]

[0055] As can be seen from the figure, the surface structure of conventional commercially available copper foil is uneven, with the rough surface exhibiting typical electrolytic copper foil deposition morphology, such as dense, nodular protrusions, dendritic, or cauliflower-like structures, formed by the uneven reduction of copper ions during the electrodeposition process. The copper foil obtained by the present invention has a micro-protrusion structure, which improves the adhesion between the current collector and the active material, thereby enhancing its peel resistance. Depending on the settings of current parameters and other factors, the shape of individual micro-protrusions, the density per unit surface area, and the distribution of micro-peaks and micro-valleys can also vary, thereby improving its peel resistance and mechanical strength.

[0056] Example 4

[0057] Cathode copper is used as raw material, and the surface oxide is removed by pickling. Then it is reacted with dilute sulfuric acid (concentration 180-220g / L) in a copper dissolving tank. The temperature is controlled at 70-90℃, and compressed air (flow rate 2m 3 / h) oxidize and dissolve the copper material to generate copper sulfate solution, and remove solid impurities through multi-stage filtration (pore size ≤ 1μm). Prepare electrolyte 1 and electrolyte 2 respectively. 2+ The concentration is 250g / L, and 5M hydrochloric acid, 8g / L sodium tungstate, and 0.3ppm sodium thiopropane sulfonate are also added; Cu in electrolyte 2 2+ The concentration is 100g / L.

[0058] Electrolytic cell configuration: anode is titanium-based coated with iridium tantalum oxide coating (DSA anode), cathode is Titanium roller (mirror polished surface, surface roughness Ra ≤ 0.1 μm), interpole distance 8-12 cm.

[0059] Add electrolyte 1 to the electrolytic cell, control the electrolyte temperature at 50±1℃ and the flow rate at 40m 3 / h. Turn on the cathode roller and rotate it at a constant speed of 8m / min. Apply DC power with a voltage of 3.1±0.05V and a current density of 30A / dm 2 Copper ions were reduced and deposited on the surface of the cathode roller. The deposition time was controlled at 90s to form a nanocrystalline layer with a thickness of 3μm (grain size 55±3nm).

[0060] Adjust the flow rate of electrolyte 1 to 30m 3 / h, and at the same time, electrolyte 2 is added to the electrolytic cell at a flow rate of 10m 3 / h, control the electrolyte temperature at 48±1℃, switch to pulse power supply, control the pulse current (on-off ratio 1:3, peak value 40A / dm 2 ), the pulse waveform (40A peak, 25% duty cycle) was confirmed by observing the oscilloscope, the deposition time was 70s, and the thickness was 7μm.

[0061] Adjust the flow rate of electrolyte 1 to 20m 3 / h, adjust the electrolyte flow rate to 10m 3 / h, control the electrolyte temperature at 45±1℃, switch the power supply to DC superimposed pulse (10A / dm 2 DC+5A / dm 2 pulse), deposition time 40s, 8μm thick dense surface layer (

[0062] After the copper foil is rotated out of the liquid surface with the roller, it is washed with high-pressure water and dried with an air knife, and then continuously peeled off from the cathode roller to form the original foil.

[0063] Example 5

[0064] Example 5 is similar to Example 4, except that the additives are: gelatin 0.8 g / L, thiourea 0.6 ppm, hydroxyethyl cellulose 1.2 g / L, polydisulfide dipropane sulfonate sodium 0.3 ppm

[0065] Example 6

[0066] Example 6 is substantially the same as Example 4, except that the additives are 0.5 g / L collagen and 0.5 ppm sodium 3-mercapto-1-propanesulfonate.

[0067] Comparative Example 1

[0068] Cathode copper is used as raw material, and the surface oxide is removed by pickling. Then it is reacted with dilute sulfuric acid (concentration 180-220g / L) in a copper dissolving tank. The temperature is controlled at 70-90℃, and compressed air (flow rate 2m 3 / h) oxidizes and dissolves copper materials to generate copper sulfate solution, and removes solid impurities through multi-stage filtration (pore size ≤ 1μm) to generate copper sulfate solution (Cu 2+ Concentration 250g / L). Electrolytic cell configuration: anode is titanium-based coated with iridium tantalum oxide coating (DSA anode), cathode is Titanium roller (mirror polished surface, surface roughness Ra ≤ 0.1 μm), interpole distance 8-12 cm.

[0069] Control the electrolyte temperature at 48±1℃ and the flow rate at 40m 3 / h. Turn on the cathode roller and rotate it at a constant speed of 8m / min. Apply DC power with a voltage of 3.1±0.05V and a current density of 30A / dm 2 The copper ions are reduced and deposited on the surface of the cathode roller. The deposition time is controlled at 200s. After the copper foil is rotated out of the liquid surface with the roller, it is washed with high-pressure water and dried with an air knife, and then continuously peeled off from the cathode roller to form the original foil.

[0070] Comparative Example 2

[0071] Comparative Example 2 is substantially the same as Comparative Example 1, except that additives are added to the electrolyte: 5M hydrochloric acid and 0.8 g / L gelatin.

[0072] Comparative Example 3

[0073] Comparative Example 3 is substantially the same as Comparative Example 1, except that additives are added to the electrolyte: 0.5 g / L collagen and 0.5 ppm sodium 3-mercapto-1-propanesulfonate.

[0074] The data of the copper foils obtained in Examples 4 to 6 and Comparative Examples 1 to 3 are shown in the following table.

[0075]

[0076] The comparison of the examples shows that the addition of additives can change the microstructure of the copper foil, which is beneficial for reducing roughness. The comparative examples show that the method of the present invention can reduce roughness without reducing peel strength, while the comparative examples show that although the roughness is reduced, the peel strength is also lost.

[0077] Example 7

[0078] The raw foil obtained in Example 1 was subjected to subsequent treatment: first, it was placed in a roughening solution (H2O2 80g / L + H2SO4 100g / L) and ultrasonically assisted (40kHz, 80W / cm2 ) for 20s. Then place it in electrolyte (Na2S2O3 15g / L+ammonium citrate 20g / L+benzimidazole 0.3g / L) and use pulse current (peak value 15A / dm 2 The morphology was controlled by immersion in a 40% duty cycle and a 500 Hz frequency for 40 seconds. Finally, the immersion was passivated in an immersion solution (KH-550 silane 1.8% + sulfur-containing polyacrylate emulsion 8% (pH = 4.0)) at 130°C for 8 minutes.

[0079] Example 8

[0080] Example 8 is substantially the same as Example 7, except that the raw foil obtained in Example 2 is subjected to subsequent treatment.

[0081] Example 9

[0082] Example 9 is substantially the same as Example 7, except that the raw foil obtained in Example 3 is subjected to subsequent treatment.

[0083] Example 10

[0084] Example 10 is substantially the same as Example 7, except that the raw foil obtained in Example 4 is subjected to subsequent treatment.

[0085]

[0086]

[0087] Further surface treatment of the original foil can produce a copper foil with a roughness of approximately 2 microns and high peel strength, meeting the special requirements of ultra-low profile copper foil required for high-frequency and high-speed electronic circuits. The above description is only a preferred embodiment of the present application and is not intended to limit the present application.

Claims

1. A method for preparing an electronic circuit copper foil, characterized in that: Follow these steps: Cathode copper is used as raw material, and the surface oxide is removed by pickling. Then it reacts with dilute sulfuric acid in a copper dissolving tank. The temperature is controlled at 70-90℃, and compressed air is introduced to oxidize and dissolve the copper material to generate copper sulfate solution. Solid impurities are removed through multi-stage filtration. Electrolyte 1 and electrolyte 2 are prepared respectively. The Cu in electrolyte 1 2 + concentration is 250±1g / L; Cu in electrolyte 2 2+ Concentration is 100±1g / L; Add electrolyte 1 to the electrolytic cell, control the electrolyte temperature at 50±1℃ and the flow rate at 40-44m 3 / h, turn on the cathode roller, rotate it at a constant speed of 8-10m / min, apply DC power, voltage of 2.3-3.1V, and control the current density at 15-30A / dm 2 , copper ions are reduced and deposited on the surface of the cathode roller, and the deposition time is controlled at 90±1s; Adjust the flow rate of electrolyte 1 to 30-32m 3 / h, and at the same time, electrolyte 2 is added to the electrolytic cell at a flow rate of 10-12m 3 / h, control the electrolyte temperature at 45-48°C, switch to pulse power supply, and the deposition time is 70-120s; Adjust the flow rate of electrolyte 1 to 20-22m 3 / h, adjust the electrolyte flow rate to 10-12m 3 / h, control the electrolyte temperature at 40-45℃, switch the power supply to DC superimposed pulse (5-10A / dm 2 DC+5-10A / dm 2 pulse), deposition time 40±1s; After the copper foil is rotated out of the liquid surface with the roller, it is washed with high-pressure water and dried with an air knife, and then continuously peeled off from the cathode roller to form the original foil.

2. The method for preparing an electronic circuit copper foil according to claim 1, wherein: The configuration of the electrolytic cell is as follows: the anode is a titanium-based anode coated with iridium-tantalum oxide, the cathode is a φ1500mm titanium roller, and the inter-electrode spacing is 8-12cm.

3. The method for preparing the electronic circuit copper foil according to claim 1, wherein: The surface of the cathode titanium roller is mirror-polished, with a surface roughness Ra≤0.1μm.

4. The method for preparing an electronic circuit copper foil according to claim 1, wherein: The pulse current has an on-off ratio of 1:3 and a peak current of 20-40A / dm 2 , observe the oscilloscope to confirm the pulse waveform.

5. The method for preparing the electronic circuit copper foil according to claim 1, wherein: The DC superimposed pulse controls the DC current to be 10A / dm 2 , superimposed pulse current is 5A / dm 2 .

6. The method for preparing an electronic circuit copper foil according to claim 1, wherein: The electrolyte 1 also contains additives.

7. The method for preparing an electronic circuit copper foil according to claim 1, wherein: The additives include one or more of hydrochloric acid, gelatin, thiourea, hydroxyethyl cellulose, collagen, sodium polydisulfide dipropane sulfonate, sodium 3-mercapto-1-propane sulfonate, and sodium alcoholthiopropane sulfonate.

8. The method for preparing an electronic circuit copper foil according to claim 1, wherein: The additives are: hydrochloric acid and gelatin, hydrochloric acid and sodium tungstate and sodium alcoholthiopropane sulfonate, gelatin and thiourea and hydroxyethyl cellulose and sodium polydisulfide propane sulfonate, collagen and sodium 3-mercapto-1-propane sulfonate.

9. The method for preparing an electronic circuit copper foil according to claim 1, wherein: The obtained raw foil was subjected to surface treatment: first placed in a roughening solution and ultrasonically treated for 20 seconds; Then it was placed in an electrolyte and treated with a pulse current for 40 seconds to control the morphology; finally, it was passivated in an immersion solution at 130°C for 8 minutes.

10. The method for preparing an electronic circuit copper foil according to claim 1, wherein: The roughening solution is H2O2 80g / L+H2SO4 100g / L; the electrolyte is: Na2S2O3 15g / L+ammonium citrate 20g / L+benzimidazole 0.3g / L; the impregnation solution is: KH-550 silane 1.8%+sulfur-containing polyacrylate emulsion 8%.

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