Improved treatment process for rough surface parameters of electrolytic copper foil

Abstract

The invention relates to the technical field of electrolytic copper foils, and discloses an improved treatment process for rough surface parameters of electrolytic copper foils, which comprises the following steps: after a thick copper electroplating procedure, performing electrochemical flattening treatment on the electrolytic copper foils, and applying current in a solution A containing nickel ions, zinc ions and chromium ions; carrying out controllable rinsing on the copper foil subjected to electrochemical leveling treatment; the copper foil subjected to controllable rinsing is subjected to chemical treatment in a solution B containing 3-amino-5-sulfydryl-1, 2, 4-triazole, and the pH value of the solution B is controlled; and finally washing and drying. According to the method, the point discharge effect is effectively inhibited through electrochemical leveling treatment, and the copper deposition mode is changed to reduce the rough surface contour height and improve the deposition uniformity; and meanwhile, a chemical bonding layer is formed on the surface of the copper foil through subsequent chemical treatment, so that the problem that the bonding force is reduced due to surface leveling is solved.

Description

Technical Field

[0001] This invention relates to the field of electrolytic copper foil technology, specifically to a process for improving the surface parameters of electrolytic copper foil. Background Technology

[0002] Electrolytic copper foil is a key basic material in the electronics and information industry, and its performance directly affects the reliability of downstream products such as printed circuit boards. Among them, the surface morphology of the rough surface of the copper foil, especially its maximum outline height (RZ), is a core technical indicator that determines its adhesion to the substrate and the accuracy of subsequent patterning processing.

[0003] Traditional electrolytic copper foil production processes typically include raw foil preparation and subsequent thick copper electroplating. In the thick copper electroplating stage, an electric current is applied to deposit copper ions from the electrolyte onto the surface of the raw foil to achieve the desired thickness. This process aims to increase the overall thickness of the copper foil and initially construct the microstructure of the rough surface, laying the foundation for subsequent surface treatment and applications.

[0004] However, due to the inherent microscopic peak-valley structure on the surface of raw foil, during thick copper electroplating, the current preferentially concentrates at the pointed tips of these microscopic protrusions, resulting in a tip discharge effect. This uneven current distribution causes copper ions to preferentially deposit at these points, leading to a continuous increase in peak height and insufficient filling of valleys. Ultimately, this results in a significant and difficult-to-control increase in the maximum outline height (RZ) of the rough copper foil surface with increasing thickness. Existing technologies typically control this by adjusting macroscopic electroplating parameters, but this cannot fundamentally change the uneven microscopic deposition trend. Therefore, there is a technical contradiction between obtaining a smooth surface and ensuring high adhesion, making it difficult to simultaneously meet the requirements of high-performance applications.

[0005] Therefore, this invention proposes an improved processing technology for the surface parameters of electrolytic copper foil to address the shortcomings of existing technologies. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an improved processing technology for the surface parameters of electrolytic copper foil, which solves the technical problem that uneven copper deposition caused by the tip discharge effect makes it difficult to effectively reduce the surface profile height while ensuring high adhesion.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a process for improving the surface parameters of electrolytic copper foil, comprising:

[0009] S1. Electrolytic copper foil is placed in treatment solution A for treatment, wherein treatment solution A is prepared by dissolving nickel sulfate, zinc oxide and chromium trioxide in deionized water;

[0010] S2. The electrolytic copper foil after step S1 is subjected to a controlled rinsing process to form a residual film containing zinc ions on the surface of the electrolytic copper foil.

[0011] S3. The electrolytic copper foil after step S2 is placed in treatment solution B for further treatment.

[0012] S4. The electrolytic copper foil processed in step S3 is then subjected to water washing and drying treatment in sequence.

[0013] In a preferred embodiment, step S1 of the above technical solution is specifically defined. This step aims to regulate the deposition behavior of copper ions through electrochemical means. The concentrations of each component in the treatment solution A are as follows: nickel ion concentration is 50-120 mg / L, zinc ion concentration is 100-120 mg / L, and chromium ion concentration is 8-15 mg / L. This treatment is carried out at a temperature of 28-32℃ and an A / dm³ ... 2 The process is carried out for 1-3 seconds at a certain current density. The nickel, zinc, and chromium ions in the treatment solution A work together to change the electric field distribution on the copper foil surface, suppress the current concentration at the protruding tips, and guide copper ions to deposit into the recessed areas, thereby achieving microscopic smoothing of the rough surface.

[0014] In a preferred embodiment, step S2 of the above technical solution is specifically defined. The purpose of this step is not to completely remove the treatment solution A from the copper foil surface, but rather to intentionally retain a functional film on its surface. Specifically, this controlled rinsing process involves spraying deionized water onto the surface of the electrolytic copper foil, wherein the spraying pressure is 0.1-0.3 MPa and the spraying time is 0.5-1.5 seconds. By controlling these parameters, a residual film containing zinc ions can be formed on the copper foil surface.

[0015] In a preferred embodiment, step S3 of the above technical solution is specifically defined. This step aims to construct a functionalized chemically bonded interface on the copper foil surface. The treatment solution B is an aqueous solution containing 3-amino-5-mercapto-1,2,4-triazole at a concentration of 50-500 ppm and a pH of 4.0-5.5. The treatment is carried out at a temperature of 30-50°C for 5-15 seconds. The residual film containing zinc ions formed in step S2 interacts with the 3-amino-5-mercapto-1,2,4-triazole molecules in step S3. Specifically, zinc ions can coordinate with the triazole ring nitrogen atom in the 3-amino-5-mercapto-1,2,4-triazole molecule. This interaction lowers the activation energy for the chemisorption and self-assembly of the 3-amino-5-mercapto-1,2,4-triazole molecules on the copper foil surface, thereby accelerating the formation of the self-assembled monolayer and inducing it to arrange in an ordered structure. Ultimately, 3-amino-5-mercapto-1,2,4-triazole forms a chemical bond with the copper foil surface through its thiol group and faces its amino group outward, thus creating a functionalized interface that can react with the subsequent resin substrate.

[0016] In a preferred embodiment, the 3-amino-5-mercapto-1,2,4-triazole is prepared by a specific method comprising: (a) reacting thiourea with hydrazine hydrate in a solvent to generate thiocarbazide; (b) subjecting the thiocarbazide obtained in step (a) to a cyclization reaction with formic acid under heating conditions to generate 3-amino-5-mercapto-1,2,4-triazole; and (c) purifying the product obtained in step (b).

[0017] In a preferred embodiment, steps S1 and S3 of the process are performed in two independent processing modules. This physical isolation is designed to prevent cross-mixing between treatment solution A and treatment solution B, avoid unintended chemical reactions between solution components, and ensure the stability of the effects of each processing step.

[0018] This invention provides a process for improving the surface parameters of electrolytic copper foil. It has the following beneficial effects:

[0019] 1. In step S1, the present invention electrochemically treats the copper foil. The specific chemical additives in the treatment solution A effectively suppress the tip discharge effect and promote the filling of microscopic depressions, thereby significantly reducing the maximum profile height in the improvement of the surface parameters of the electrolytic copper foil. Simultaneously, after the interface pretreatment in step S2, the 3-amino-5-mercapto-1,2,4-triazole introduced in step S3 forms a chemical bond between the copper foil and the substrate. This not only compensates for the loss of mechanical bonding force caused by surface smoothing but also improves the final peel strength, resolving the technical contradiction between surface smoothness and bonding force.

[0020] 2. This invention modifies the continuous production process of electrolytic copper foil, particularly through precise control of current and ion concentration in step S1, thereby altering the deposition pattern of metal ions. This improved process transforms ion deposition from a tip-preferential deposition to a filling deposition pattern towards the micro-valve bottom of the rough surface. This shift in deposition pattern results in a more uniform thickness distribution of the final copper foil, effectively optimizing the product's thickness parameters, reducing potential subsequent processing problems caused by uneven thickness, and improving batch stability.

[0021] 3. This invention designs the process for improving the surface parameters of electrolytic copper foil as an independent module in a continuous production line. This allows the process to be directly added to the downstream section of existing electrolytic copper foil production lines without requiring large-scale modifications to the main equipment, exhibiting excellent process compatibility and integrability. Furthermore, the chemical substances and processing conditions used in this process, while achieving surface morphology control, do not negatively impact the inherent conductivity and mechanical properties of the copper foil, ensuring that the final product meets the performance requirements of subsequent bonding and etching processes. Attached Figure Description

[0022] Figure 1 This is a process flow diagram of the present invention;

[0023] Figure 2 This is a schematic diagram of the additive-free version of the present invention;

[0024] Figure 3 This is a schematic diagram of the additives used in this invention. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0027] Nickel sulfate, CAS: 7786-81-4.

[0028] Zinc oxide, CAS: 1314-13-2.

[0029] Chromium trioxide, CAS: 1308-38-9.

[0030] 3-Amino-5-mercapto-1,2,4-triazole: prepared in-house, preparation method is described in Preparation Example 1, purity ≥99.5% as determined by high performance liquid chromatography (HPLC).

[0031] Thiourea, CAS: 62-56-6.

[0032] Hydrazine hydrate, CAS: 7803-57-8.

[0033] Formic acid, CAS: 64-18-6.

[0034] Citric acid, CAS: 77-92-9.

[0035] Preparation Example 1 (3-amino-5-mercapto-1,2,4-triazole):

[0036] (a) Synthesis of Thiocarbazide: In a 1000 mL three-necked flask equipped with a magnetic stirrer, thermometer, and reflux condenser, 76.12 g (1.0 mol) of thiourea and 200 mL of deionized water were added sequentially. Stirring was started, and after the thiourea partially dissolved, 125.13 g (2.0 mol) of an 80% (w / w) aqueous solution of hydrazine hydrate was slowly added dropwise. The dropwise addition was completed within 30 minutes, during which the system temperature spontaneously increased. After the addition was complete, the reaction mixture was heated to 100-105 °C and refluxed at this temperature for 4 hours. During this period, hydrogen sulfide gas was generated, which needed to be treated by connecting to a tail gas absorption device (such as sodium hydroxide solution). After the reaction was completed, heating was stopped, and the reaction solution was allowed to cool naturally at room temperature, followed by further cooling to below 5 °C in an ice-water bath, resulting in the precipitation of a large amount of white solid. The solid was filtered under reduced pressure through a Buchner funnel, and the filter cake was washed 2-3 times with a small amount of chilled deionized water to remove residual hydrazine hydrate. The obtained white solid filter cake was dried in a vacuum drying oven at 60°C for 6 hours to obtain the intermediate product thiocarbazide, which was weighed and the yield was calculated.

[0037] (b) Cyclization of 3-amino-5-mercapto-1,2,4-triazole: 106.14 g (1.0 mol) of dried thiocarbazide obtained in step (a) and 208.8 g (4.0 mol) of 88% (w / w) formic acid were added to the aforementioned three-necked flask. Stirring was started, and the mixture was heated to 110-120 °C and refluxed at this temperature for 5 hours. Initially, the system was a clear solution, which gradually became viscous and solids precipitated. After the reaction was complete, heating was stopped, and the reaction mixture was allowed to cool to room temperature.

[0038] (c) Purification of the product: Slowly add 800 mL of deionized water to the cooled reaction mixture obtained in step (b) and stir to disperse it into a slurry. Heat the slurry to 90-95°C to dissolve most of the solids. Filter under reduced pressure while hot to remove a small amount of insoluble impurities. Collect the hot filtrate and slowly cool it at room temperature. During cooling, the target product gradually precipitates as white needle-like crystals. After the filtrate has completely cooled, place it in an ice-water bath for 1 hour to ensure complete crystallization. Filter under reduced pressure again, collect the crystals, and wash with a small amount of deionized water. Dry the obtained pure crystals in a vacuum drying oven at 70°C for 8 hours to obtain the final product 3-amino-5-mercapto-1,2,4-triazole. The purity is greater than 99.5% as determined by high-performance liquid chromatography (HPLC). Store the product in a desiccator for later use.

[0039] Please see the appendix Figures 1-3 .

[0040] Example 1:

[0041] This embodiment describes a process for improving the surface parameters of raw copper foil after it has undergone a thick copper electroplating process on a continuous electrolytic copper foil production line. The production line is set to operate at a speed of 20 meters per minute.

[0042] Previous process: After the electrolytic copper foil raw foil has undergone a thick copper electroplating process, the copper foil is processed at a linear speed of 20 meters per minute.

[0043] S1 processing:

[0044] Solution A preparation: Add deionized water to the treatment tank, then dissolve the additives sequentially: nickel sulfate and chromium trioxide. Finally, dissolve zinc oxide in a small amount of dilute sulfuric acid before adding it to the treatment tank, and replenish with deionized water to the predetermined volume, so that the nickel ions in the solution (Ni) are present. 2+ The concentration was 80 mg / L, and the zinc ion concentration (Zn) was... 2+ The concentration was 110 mg / L, and the chromium ion concentration (Cr) was... 3+ The concentration is 12 mg / L.

[0045] Processing procedure: The temperature of treatment solution A is controlled at 30℃ by a temperature control unit. Electrolytic copper foil is passed through a treatment tank with an effective length of 0.7 meters at a linear velocity of 20 meters / minute for 2 seconds. During this process, 40-110 A / dm² is applied via a DC rectifier. 2 The current within the range is set to a current density of 80 A / dm² in this embodiment. 2 .

[0046] S2 processing:

[0047] Controlled rinsing: The copper foil treated with S1 immediately enters a spray zone with an effective length of 0.3 meters. Deionized water is sprayed onto the surface of the copper foil using a high-pressure spray device. The spray pressure is set to 0.2 MPa, and the spray time is 1 second.

[0048] S3 processing:

[0049] Solution B preparation: In a separate treatment tank, the 3-amino-5-mercapto-1,2,4-triazole obtained in Preparation Example 1 was dissolved in deionized water to prepare an aqueous solution with a concentration of 200 ppm. Subsequently, the pH of the solution was precisely adjusted to 4.8 using an aqueous citric acid solution.

[0050] Processing procedure: The temperature of the treatment solution B is controlled at 40℃ by a temperature control unit. The copper foil treated by S2 passes through a treatment tank with an effective length of 3.3 meters at a linear speed of 20 meters / minute, and the treatment time is 10 seconds.

[0051] S4 processing:

[0052] Washing and Drying: The copper foil treated with S3 is thoroughly cleaned by passing it through a multi-stage deionized water rinsing tank, and finally dried by a hot air drying device to obtain the final product. After processing, the copper foil undergoes standard subsequent washing and drying processes, and is finally rolled up into the finished product.

[0053] Example 2:

[0054] This embodiment describes a process for improving the surface parameters of raw copper foil after it has undergone a thick copper electroplating process on a continuous electrolytic copper foil production line. The production line is set to operate at a speed of 20 meters per minute.

[0055] Previous process: After the electrolytic copper foil raw foil undergoes a thick copper electroplating process, its maximum outline height (RZ) on the rough surface is 4.6 μm. This copper foil is processed at a linear speed of 20 m / min.

[0056] S1 processing:

[0057] Solution A preparation: Add deionized water to the treatment tank, then dissolve the additives sequentially: nickel sulfate and chromium trioxide. Finally, dissolve zinc oxide in a small amount of dilute sulfuric acid before adding it to the treatment tank, and replenish with deionized water to the predetermined volume, so that the nickel ions in the solution (Ni) are present. 2+ The concentration is 50 mg / L, zinc ions (Zn) 2+ The concentration is 100 mg / L, chromium ions (Cr 3+ ).

[0058] The concentration is 8 mg / L.

[0059] Processing procedure: The temperature of treatment solution A is controlled at 28℃ by a temperature control unit. Electrolytic copper foil is passed through a treatment tank with an effective length of 1 meter at a linear velocity of 20 meters per minute for 3 seconds. During this process, the current density applied through the DC rectifier is set to 40 A / dm³. 2 .

[0060] S2 processing:

[0061] Controlled rinsing: The copper foil treated with S1 immediately enters a spray zone with an effective length of 0.5 meters. Deionized water is sprayed onto the surface of the copper foil using a high-pressure spray device. The spray pressure is set to 0.1 MPa, and the spray time is 1.5 seconds.

[0062] S3 processing:

[0063] Solution B preparation: In a separate treatment tank, the 3-amino-5-mercapto-1,2,4-triazole obtained in Preparation Example 1 was dissolved in deionized water to prepare an aqueous solution with a concentration of 50 ppm. Subsequently, the pH of the solution was precisely adjusted to 4.0 using an aqueous citric acid solution.

[0064] Processing procedure: The temperature of the treatment solution B is controlled at 30℃ by a temperature control unit. The copper foil treated by S2 passes through a treatment tank with an effective length of 5 meters at a linear speed of 20 meters / minute, and the treatment time is 15 seconds.

[0065] S4 processing:

[0066] Washing, Drying, and Rewinding: The copper foil treated with S3 is thoroughly washed in a multi-stage deionized water rinsing tank to remove any residual treatment solution from the surface. After washing, the copper foil is dried using a hot air drying device. Following standard subsequent washing and drying processes, the copper foil is finally rewound into the finished product.

[0067] Example 3:

[0068] This embodiment describes a process for improving the surface parameters of raw copper foil after it has undergone a thick copper electroplating process on a continuous electrolytic copper foil production line. The production line is set to operate at a speed of 20 meters per minute.

[0069] Previous process: After the electrolytic copper foil raw foil undergoes a thick copper electroplating process, its maximum outline height (RZ) on the rough surface is 4.6 μm. This copper foil is processed at a linear speed of 20 m / min.

[0070] S1 processing:

[0071] Solution A preparation: Add deionized water to the treatment tank, then dissolve the additives sequentially: nickel sulfate and chromium trioxide. Finally, dissolve zinc oxide in a small amount of dilute sulfuric acid before adding it to the treatment tank, and replenish with deionized water to the predetermined volume, so that the nickel ions in the solution (Ni) are present. 2+ The concentration was 120 mg / L, and the zinc ion concentration (Zn) was... 2+ The concentration was 120 mg / L, and the chromium ion concentration was 120 mg / L. 3+ The concentration is 15 mg / L.

[0072] Processing procedure: The temperature of treatment solution A is controlled at 32℃ by a temperature control unit. Electrolytic copper foil passes through a treatment tank with an effective length of 0.33 meters at a linear velocity of 20 meters per minute for 1 second. During this process, the current density applied through the DC rectifier is set to 110 A / dm³. 2 .

[0073] S2 processing:

[0074] Controlled rinsing: The copper foil treated with S1 immediately enters a spray zone with an effective length of 0.17 meters. Deionized water is sprayed onto the surface of the copper foil using a high-pressure spray device. The spray pressure is set to 0.3 MPa, and the spray time is 0.5 seconds.

[0075] S3 processing:

[0076] Solution B preparation: In a separate treatment tank, the 3-amino-5-mercapto-1,2,4-triazole obtained in Preparation Example 1 was dissolved in deionized water to prepare an aqueous solution with a concentration of 500 ppm. Subsequently, the pH of the solution was precisely adjusted to 5.5 using an aqueous citric acid solution.

[0077] Processing procedure: The temperature of the treatment solution B is controlled at 50℃ by a temperature control unit. The copper foil treated by S2 passes through a treatment tank with an effective length of 1.67 meters at a linear speed of 20 meters / minute, and the treatment time is 5 seconds.

[0078] S4 processing:

[0079] Washing, Drying, and Rewinding: The copper foil treated with S3 is thoroughly washed in a multi-stage deionized water rinsing tank to remove any residual treatment solution from the surface. After washing, the copper foil is dried using a hot air drying device. Following standard subsequent washing and drying processes, the copper foil is finally rewound into the finished product.

[0080] Comparative Example 1:

[0081] Compared with Example 1, the difference is that after the electrolytic copper foil has undergone the thick copper electroplating process, it does not go through the S1, S2 and S3 processes of the present invention, but directly undergoes the water washing, drying and winding in step S4.

[0082] Comparative Example 2:

[0083] Compared with Example 1, the difference is that step S1 is omitted, and the electrolytic copper foil is directly processed in steps S2, S3 and S4 after the thick copper electroplating process.

[0084] Comparative Example 3:

[0085] Compared with Example 1, the difference is that step S3 is omitted. After the electrolytic copper foil has been processed in steps S1 and S2, it is directly subjected to step S4 of washing, drying and winding.

[0086] Comparative Example 4:

[0087] Compared with Example 1, the difference is that the controlled rinsing process in step S2 is replaced by a thorough rinsing process, specifically by spraying deionized water at a pressure of 0.5 MPa for 10 seconds to ensure that there is no residue of treatment solution A on the surface of the copper foil.

[0088] Comparative Example 5:

[0089] Compared with Example 1, the difference is that the pH value of the treatment solution B in step S3 is adjusted to 6.5, which exceeds the range of 4.0-5.5 of the present invention. All other conditions are the same as in Example 1.

[0090] Test Example 1 (Electrolytic Copper Foil Surface Parameter Test):

[0091] This test case aims to quantitatively evaluate the change in the maximum profile height (RZ) of the rough surface of electrolytic copper foil after different process treatments in the examples and comparative examples.

[0092] The experimental instrument was a Mitutoyo SJ-410 stylus profilometer. The tests were conducted according to GB / T 3505-2009 standard. Before testing, a standard roughness sample with a nominal RZ value of 3.0 μm was used to calibrate the instrument. This value is close to the RZ measurement range of the copper foil sample prepared in this embodiment of the invention. After repeatedly measuring the standard sample and confirming that the deviation between the instrument reading and the nominal value did not exceed ±5%, the measurement of the sample began.

[0093] The experimental steps are as follows:

[0094] Sampling: Samples with a size of 10cm × 10cm were cut from the finished copper foil rolls obtained in Examples 1-3 and Comparative Examples 1-5.

[0095] Instrument parameters: The sampling length (λc) is set to 0.8 mm, the evaluation length (ln) to 4.0 mm, the probe tip radius to 2 μm, and the measurement speed to 0.5 mm / s.

[0096] Measurement: Fix the copper foil sample flat on the measuring platform, and randomly select 5 measuring points on its rough surface that are more than 1 cm apart. Start the instrument and perform a profile measurement at each measuring point along a direction perpendicular to the copper foil production direction.

[0097] Data recording and calculation: The instrument automatically calculates and displays the RZ value for each measurement point. Record these 5 RZ values ​​and calculate their arithmetic mean as the final RZ value for the sample.

[0098] The electrolytic copper foil samples obtained in Examples 1-3 and Comparative Examples 1-5 were subjected to performance tests according to the above method, and the results are summarized in Table 1 below.

[0099]

[0100] Performance test results analysis:

[0101] The test data in Table 1 show that the copper foil samples processed according to Examples 1-3 have significantly lower average RZ values ​​than all comparative sample samples. Comparative Example 1, without any special treatment, has the highest average RZ value and can be considered the baseline. The sample in Comparative Example 2, having omitted step S1, has an average RZ value similar to the baseline Comparative Example 1 sample, indicating that step S1 plays a decisive role in reducing the surface roughness of the final product.

[0102] The electrochemical treatment in step S1 is crucial for achieving improved surface profile. At a specific current density, the deposition behavior of metal ions in solution A on the copper foil surface is modulated. This process suppresses preferential deposition in microscopic protrusions, thus weakening the tip discharge effect, while simultaneously promoting ion filling into microscopic depressions. This selective deposition produces a physical smoothing effect, directly reducing the maximum profile height of the copper foil surface. Therefore, Comparative Example 2, lacking step S1, failed to achieve an effective reduction in the RZ value.

[0103] Comparing the results of Example 1 with those of Comparative Examples 3, 4, and 5, it is evident that a complete process sequence is necessary to achieve optimal results. Comparative Example 3, which omitted step S3, had a higher average RZ value than the examples, indicating that step S3 further optimizes the final surface morphology. Comparative Example 4 employed thorough rinsing, but its results were inferior to the examples, confirming that controlled rinsing in step S2 is a prerequisite for the effectiveness of subsequent steps. Comparative Example 5 performed step S3 under unsuitable pH conditions, and its results were also inferior to the examples, indicating that the action environment of the 3-amino-5-mercapto-1,2,4-triazole molecule has specific requirements. Therefore, this technical solution achieves effective control over the maximum height of the rough surface profile of electrolytic copper foil through the synergistic effect of electrochemical smoothing in step S1, interface pretreatment in step S2, and surface chemical modification in step S3.

[0104] Test Example 2 (Peel Strength Test):

[0105] This test case aims to quantitatively evaluate the peel strength of electrolytic copper foils treated with different processes in the examples and comparative examples after lamination with a standard substrate.

[0106] The experimental instrument was an Instron 5967 universal testing machine. Tests were conducted according to IPC-TM-6502.4.8 standard. The substrate material used in the experiment was FR-4 epoxy resin substrate, and the prepreg was type 1080 prepreg.

[0107] The experimental steps are as follows:

[0108] Laminate preparation: The copper foil samples obtained in Examples 1-3 and Comparative Examples 1-5 were cut into 25cm × 25cm sizes. An FR-4 substrate was taken, and two layers of 1080 prepreg were applied to it. The cut copper foil samples were then placed with the rough side facing the prepreg. This laminated structure was placed in a laminator and hot-pressed at 185°C and 3.0MPa for 90 minutes to produce a copper-clad laminate.

[0109] Test strip preparation: The cooled copper-clad laminate is cut into test strips with a width of 3.2 mm and a length of 100 mm using a precision cutting machine.

[0110] Peel test: Fix the test strip on the fixture of the universal testing machine. Peel the copper foil layer from the FR-4 substrate at a constant speed of 50 mm / min and a 90° angle. The testing machine automatically records the force changes during the peeling process.

[0111] Data Recording and Calculation: Data from the stable segment of the peel force-displacement curve were selected, and the average peel force was calculated. This average force was divided by the width of the test strip (3.2 mm) to obtain the peel strength, in N / mm. For each group of samples, three test strips were prepared and tested, their peel strengths were recorded, and the arithmetic mean was calculated.

[0112] The electrolytic copper foil samples obtained in Examples 1-3 and Comparative Examples 1-5 were subjected to performance tests according to the above method, and the results are summarized in Table 2 below.

[0113]

[0114] Performance test results analysis:

[0115] The test data in Table 2 clearly show that the copper foil samples prepared in Examples 1-3 all exhibited high average peel strength, significantly higher than the corresponding values ​​of all comparative sample samples. This result indicates that the complete process sequence described in this technical solution can effectively enhance the adhesion between the copper foil and the substrate. Comparative Example 1, as the baseline sample, showed a lower peel strength, reflecting the inherent bonding properties of the untreated copper foil.

[0116] The data from Comparative Example 3 (step S3 omitted) is particularly crucial. Its peel strength is not only significantly lower than the examples, but even lower than the baseline Comparative Example 1. This confirms that the electrochemical smoothing in step S1, while reducing RZ, also weakens the purely mechanical interlocking force. Therefore, the chemical treatment in step S3 is the decisive factor in obtaining high peel strength. The 3-amino-5-mercapto-1,2,4-triazole molecule used in step S3 has a thiol group (-SH) in its molecular structure that can form a strong chemical bond with copper atoms, while its amino group (-NH2) and triazole ring structure can chemically crosslink or form hydrogen bonds with the epoxy resin in the FR-4 substrate during hot pressing. This interface layer established through chemical bonding has a bonding strength far exceeding that of physical mechanical interlocking, which is the core mechanism by which this technical solution obtains high peel strength.

[0117] The results of Comparative Examples 2, 4, and 5 further reveal the synergistic effect between the steps. The peel strength of Comparative Example 2 (step S1 omitted) is lower than that of Example 1, indicating that the homogenized surface formed in step S1 is the basis for obtaining consistent and effective bonding in subsequent chemical treatment. The peel strength of Comparative Example 4 (thorough rinsing) and Comparative Example 5 (inappropriate pH value) is lower than that of Example 1, indicating that the specific surface active state constructed by the controlled rinsing in step S2, and the precise pH environment in step S3, are necessary conditions to ensure the effective formation of high-quality interfacial chemical bonds by 3-amino-5-mercapto-1,2,4-triazole molecules. In summary, this technical solution systematically solves the relationship between copper foil surface morphology and interfacial bonding through a continuous process including electrochemical smoothing, controlled interface pretreatment, and specific chemical bonding, ultimately achieving a significant improvement in peel strength.

[0118] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for improving the surface parameters of electrolytic copper foil, characterized in that, include: S1. Electrolytic copper foil is placed in treatment solution A for treatment, wherein treatment solution A is prepared by dissolving nickel sulfate, zinc oxide and chromium trioxide in deionized water; S2. The electrolytic copper foil after step S1 is subjected to a controlled rinsing process to form a residual film containing zinc ions on the surface of the electrolytic copper foil. S3. The electrolytic copper foil after step S2 is placed in treatment solution B for further treatment. S4. The electrolytic copper foil processed in step S3 is then subjected to water washing and drying processes in sequence.

2. The process for improving the surface parameters of electrolytic copper foil according to claim 1, characterized in that, In step S1, the concentration of nickel ions in the treatment solution A is 50-120 mg / L, the concentration of zinc ions is 100-120 mg / L, and the concentration of chromium ions is 8-15 mg / L.

3. The process for improving the surface parameters of electrolytic copper foil according to claim 1, characterized in that, In step S1, the step of placing the electrolytic copper foil in the treatment solution A is performed at a temperature of 28-32℃ and an A / dm³ ... 2 Perform for 1-3 seconds at a current density.

4. The process for improving the surface parameters of electrolytic copper foil according to claim 1, characterized in that, In step S2, the controlled rinsing treatment of the electrolytic copper foil after step S1 specifically involves spraying the surface of the electrolytic copper foil with deionized water, wherein the spraying pressure is 0.1-0.3 MPa and the spraying time is 0.5-1.5 seconds.

5. The process for improving the surface parameters of electrolytic copper foil according to claim 1, characterized in that, In step S3, the treatment solution B is an aqueous solution containing 3-amino-5-mercapto-1,2,4-triazole, wherein the concentration of 3-amino-5-mercapto-1,2,4-triazole is 50-500 ppm and the pH value is 4.0-5.

5.

6. The process for improving the surface parameters of electrolytic copper foil according to claim 5, characterized in that, The 3-amino-5-mercapto-1,2,4-triazole was prepared by the following steps: (a) React thiourea with hydrazine hydrate in a solvent to generate thiocarbazide; (b) The thiocarbazide obtained in step (a) is subjected to a cyclization reaction with formic acid under heating conditions; (c) The reaction product of step (b) is purified to obtain the 3-amino-5-mercapto-1,2,4-triazole.

7. The process for improving the surface parameters of electrolytic copper foil according to claim 1, characterized in that, In step S3, the step of placing the electrolytic copper foil treated in step S2 into the treatment solution B is carried out at a temperature of 30-50°C for 5-15 seconds.

8. The process for improving the surface parameters of electrolytic copper foil according to claim 1, characterized in that, The processing in step S1 and the processing in step S3 are performed in two independent processing modules.

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