Copper surface treatment liquid as well as preparation method and application thereof

Abstract

The invention discloses copper surface treatment liquid as well as a preparation method and application thereof, and relates to the field of metal surface treatment. The treating fluid comprises a basic micro-etching component, a surfactant, an azole anti-oxygen component, a stabilizer, an accelerator and water, and the basic micro-etching component comprises sulfuric acid and hydrogen peroxide; the surfactant is prepared from at least one of fatty alcohol-polyoxyethylene ether, sodium dodecyl benzene sulfonate and cocamidopropyl betaine; the azole anti-oxygen component is prepared from at least one of benzotriazole, methyl benzotriazole and mercaptobenzothiazole. When the treating fluid is used for micro-etching treatment of the copper surface of the PCB, the oxidability and the acid solubility of a system are ensured by adopting the basic micro-etching component, and grease can be efficiently removed and micro-etching is uniform in combination with the surfactant; and an azole anti-oxidation component is introduced to form a compact anti-oxidation protection layer on the copper surface, so that a three-in-one treatment effect of efficient micro-etching, oil removal and anti-oxidation protection is achieved, and the continuous and short-process production requirements of the horizontal line can be met.

Description

Technical Field

[0001] This invention relates to the field of metal surface treatment, and more particularly to a copper surface treatment liquid, its preparation method, and its application. Background Technology

[0002] With the rapid development of microelectronics technology, printed circuit board (PCB) manufacturing is moving towards multi-layering, functionalization, and density, placing increasingly higher demands on electroplating processes. In the PCB production process, after full-board copper plating and pattern transfer, grease, metal oxides, and other impurities may appear on the circuit surface. It is necessary to remove these greases and oxides from the copper surface of the circuit board to keep it clean and increase its wettability, ensuring no residue remains during subsequent cleaning.

[0003] Traditional PCB surface treatment processes after electroplating require multiple steps, including alkaline degreasing, water washing, acid pickling and micro-etching, water washing, acid pickling, and water washing again. This approach is unsuitable for continuous, short-process production and suffers from problems such as lengthy processes, large equipment footprints, high water consumption, and severe cross-contamination of chemicals. Other simplified processes typically use highly alkaline pretreatment solutions for degreasing and micro-etching. These solutions are highly aggressive towards copper surfaces, produce uneven micro-etching, and lack any anti-oxidation function. This leads to easy oxidation of the PCB during inter-process waiting, severely impacting the final product yield. Summary of the Invention

[0004] This invention provides a copper surface treatment liquid, its preparation method, and its application. This treatment liquid has a three-in-one effect of degreasing, micro-etching, and anti-oxidation protection on the copper surface of PCBs. It can improve degreasing and anti-oxidation protection while providing uniform micro-etching, and can be applied to the production requirements of horizontal continuous and short-process production.

[0005] To address the aforementioned technical problems, one objective of this invention is to provide a copper surface treatment liquid, comprising the following components in parts by weight, based on 100 parts by weight: Basic micro-etching components: 8-15 parts; Surfactant: 5-12 parts; Azole antioxidant component: 1-4 parts; Stabilizer: 3-7 parts; Accelerator: 0.1-10 parts; Water: Balance; The surfactant is at least one of fatty alcohol polyoxyethylene ether, sodium dodecylbenzenesulfonate, and cocamidopropyl betaine; the azole antioxidant component includes at least one of benzotriazole, methylbenzotriazole, and mercaptobenzothiazole.

[0006] In some embodiments, the basic micro-etching components include sulfuric acid and hydrogen peroxide.

[0007] When this copper surface treatment solution is used for micro-etching of PCB copper surfaces, it employs a basic micro-etching component to ensure the oxidizing and acidic properties of the system, allowing the normal micro-etching reaction of copper to occur. The added stabilizer ensures the stability of the hydrogen peroxide, with etching rate fluctuations ≤ ±5%, while the added accelerator accelerates the reaction rate. Combined with a surfactant, it provides highly efficient grease removal, thoroughly removing complex oil stains, and is low-foaming and easily volatile, ensuring uniform micro-etching. The introduction of an azole-based antioxidant component ensures compatibility with acidic micro-etching systems and forms a dense, long-lasting antioxidant protective layer on the copper surface, making it less prone to oxidation and enhancing its antioxidant properties. Furthermore, the azole-based antioxidant component used in this copper surface treatment solution possesses superior antioxidant function compared to other antioxidant components. This azole-based antioxidant component exhibits excellent adaptability and compatibility in the acidic system of the treatment solution, effectively enhancing the antioxidant effect on the copper surface.

[0008] In some embodiments, the surfactant comprises a fatty alcohol polyoxyethylene ether and sodium dodecylbenzene sulfonate in a mass ratio of (1-3):1.

[0009] The copper surface treatment solution of this application uses the above-mentioned compounded surfactant to improve the removal rate of fingerprints and rolling oil, and avoid oil contamination of fine circuits. While ensuring thorough degreasing of the PCB copper surface, it can also work in conjunction with the basic micro-etching components to improve micro-etching stability, extend the service life of the treatment solution, and achieve a high yield of PCB boards after treatment.

[0010] In some embodiments, the stabilizer includes at least one of p-hydroxybenzoic acid, sodium gluconate, disodium EDTA, and sodium citrate.

[0011] In some embodiments, the stabilizer is sodium gluconate and / or p-hydroxybenzoic acid.

[0012] In some embodiments, the accelerator is at least one of triethanolamine, sodium hydroxymethylsulfonate, and polyethylene glycol 400.

[0013] To solve the above-mentioned technical problems, the second objective of this invention is to provide a method for preparing a copper surface treatment solution, comprising the following steps: first, adding at least half of the water and all of the sulfuric acid, stirring and mixing and cooling to room temperature, then adding a surfactant, an azole antioxidant component, a stabilizer and an accelerator and stirring and mixing evenly, then adding hydrogen peroxide, and finally adding the remaining water and stirring and mixing evenly to obtain the copper surface treatment solution.

[0014] To address the aforementioned technical problems, a third objective of this invention is to provide an application of a copper surface treatment liquid in the micro-etching process of copper surfaces on printed circuit boards.

[0015] In some embodiments, the copper surface of the printed circuit board is immersed in a constant temperature water bath at 25-35 ℃ for 0.5-1.5 min, then removed, cleaned, and dried to complete the micro-etching process.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. When the copper surface treatment solution of this application is used for micro-etching of PCB copper surfaces, it adopts basic micro-etching components to ensure the oxidizing properties and certain acidic solubility of the system, allowing the normal micro-etching reaction of copper to occur. Combined with surfactants, it efficiently removes grease and ensures uniform micro-etching. A azole antioxidant component is introduced to form a dense and long-lasting antioxidant protective layer on the copper surface; a stabilizer is introduced to ensure the stability of hydrogen peroxide, allowing the reaction to occur stably; and an accelerator is introduced to make the reaction rate faster and the micro-etching more efficient. It has a three-in-one treatment effect of degreasing, micro-etching, and antioxidant protection, replacing multiple steps in one step, reducing equipment and time costs. It adopts a phosphorus-free, low-COD formula, which is suitable for green manufacturing requirements.

[0017] 2. The copper surface treatment solution of this application introduces azole antioxidant components to form a dense and long-lasting antioxidant protective layer on the copper surface. The azole antioxidant components have excellent adaptability and compatibility in the acidic system of the treatment solution, thus comprehensively ensuring product quality.

[0018] 3. The stabilizer added to the copper surface treatment solution in this application ensures the stability of hydrogen peroxide, guarantees the stability of the micro-etching rate, and controls the etching rate at 5-8 μm / min; the added accelerator can accelerate the reaction rate, making the micro-etching more efficient. Attached Figure Description

[0019] Figure 1 This refers to the electrolytic copper foil surface that, after treatment with a copper surface treatment solution for 120 hours, exhibits no oxidation and uniform micro-etching. Figure 2 The copper foil surface was electrolyzed 120 h after treatment with a copper surface treatment solution in Comparative Example 2 of this invention. Figure 3 The copper foil surface was electrolyzed 120 hours after treatment with a copper surface treatment solution, as described in Comparative Example 7 of this invention. Detailed Implementation

[0020] The technical solutions of 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.

[0021] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0022] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0023] As used in this article: In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0024] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0025] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicating orientation or positional relationship are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0026] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention. Unless otherwise specified, the raw materials used in the following embodiments and comparative examples are all commercially available, and the same raw materials were used in parallel experiments.

[0027] Example 1 A copper surface treatment solution, based on a total volume of 100 kg, comprises 8 kg of basic micro-etching components, 5 kg of surfactant, 1 kg of azole-based antioxidant components, 3 kg of stabilizer, 2 kg of accelerator, and the balance being deionized water. The basic micro-etching components include sulfuric acid and hydrogen peroxide in a mass ratio of 5:3. The surfactant is fatty alcohol polyoxyethylene ether, the azole-based antioxidant component is benzotriazole, the stabilizer is p-hydroxybenzoic acid, and the accelerator is triethanolamine.

[0028] The preparation method of the copper surface treatment solution mentioned above includes the following steps: first, add at least half of the deionized water, then add sulfuric acid from the basic micro-etching component, stir and mix, cool to room temperature, then add surfactant, azole antioxidant component, stabilizer and accelerator, stir and mix evenly, add hydrogen peroxide from the basic micro-etching component, and finally add the remaining deionized water, stir and mix evenly to obtain the copper surface treatment solution.

[0029] Example 2 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that, based on a total volume of 100 kg of treatment solution, it includes 12 kg of basic micro-etching component, 8 kg of surfactant, 3 kg of azole antioxidant component, 5 kg of stabilizer, 4 kg of accelerator and the balance of deionized water. The basic micro-etching component includes sulfuric acid and hydrogen peroxide in a mass ratio of 7:5, the surfactant is sodium dodecylbenzenesulfonate, the azole antioxidant component is methylbenzotriazole, the stabilizer is sodium gluconate, and the accelerator is sodium hydroxymethylsulfonate.

[0030] Example 3 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that, based on a total volume of 100 kg of treatment solution, it includes 15 kg of basic micro-etching component, 12 kg of surfactant, 4 kg of azole antioxidant component, 7 kg of stabilizer, 5 kg of accelerator and the balance of deionized water. The basic micro-etching component includes sulfuric acid and hydrogen peroxide in a mass ratio of 10:5, the surfactant is cocamidopropyl betaine, the azole antioxidant component is mercaptobenzothiazole, the stabilizer is disodium EDTA, and the accelerator is polyethylene glycol 400.

[0031] Example 4 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that the surfactant includes fatty alcohol polyoxyethylene ether and sodium dodecylbenzene sulfonate in a mass ratio of 1:1.

[0032] Example 5 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that the surfactant includes cocamidopropyl betaine and sodium dodecylbenzene sulfonate in a mass ratio of 1:1.

[0033] Example 6 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that the surfactant includes fatty alcohol polyoxyethylene ether and cocamidopropyl betaine in a mass ratio of 1:1.

[0034] Example 7 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, except that the amount of accelerator added is 5 kg.

[0035] Example 8 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, except that the amount of accelerator added is 10 kg.

[0036] Example 9 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that the stabilizer is sodium gluconate.

[0037] Example 10 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that the stabilizer is disodium EDTA.

[0038] Example 11 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that the stabilizer is sodium citrate.

[0039] Comparative Example 1 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that the surfactant is replaced by an equal amount of deionized water.

[0040] Comparative Example 2 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that the azole antioxidant component is replaced by an equal amount of deionized water.

[0041] Comparative Example 3 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that the stabilizer is replaced by an equal amount of deionized water.

[0042] Comparative Example 4 A copper surface treatment solution, the steps and reagents, equipment and process parameters used in each step are the same as in Example 1, the difference is that the accelerator is replaced by an equal amount of deionized water.

[0043] Comparative Example 5 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that the surfactant is Tween-80.

[0044] Comparative Example 6 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that the surfactant is hexadecyltrimethylammonium bromide (CTAB).

[0045] Comparative Example 7 A copper surface treatment solution, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that the azole antioxidant component is replaced by an equal amount of 2,6-di-tert-butyl-p-cresol.

[0046] Performance verification test 1. Micro-etching rate test: (1) Select electrolytic copper foil with a purity ≥ 99.9%, cut it into samples of 40 mm × 40 mm × (35 ± 5 μm), wipe the surface with anhydrous ethanol to remove oil stains, rinse with deionized water and dry in an oven at 60℃ for 30 min, cool to room temperature and weigh it with an electronic balance with an accuracy of 0.1 mg (recorded as m1), and measure the actual area (recorded as S); (2) Pour the treatment solution prepared in the example or comparative example into the constant temperature reaction tank and control the temperature at 30.0±0.5℃; completely immerse the copper foil sample in the treatment solution, take it out after 60±2 s, rinse it with deionized water for 30 s immediately, dry it in a 60℃ oven for 30 min, and weigh it after cooling (recorded as m2). (3) The micro-etching rate V (unit: μm / min) is calculated according to the following formula: V=[(m1-m2)×10 4 ] / (ρ×S×t); where m1 is the mass of copper foil before treatment (g); m2 is the mass of copper foil after treatment (g); ρ is the density of copper (8.96 g / cm³); S is the surface area of ​​copper foil (cm²); t is the treatment time (min); 10 4 The unit conversion factor is used to convert g / cm to μm; two groups were tested for each example or comparative example, and each group was tested in parallel three times. The average micro-etching rate obtained from the test is shown in Table 1 below.

[0047] 2. Hydrogen peroxide stability test: (1) Prepare reagents: 50% (w / w) sulfuric acid solution, 0.1 mol / L potassium permanganate standard solution; (2) Take 1.0 mL of the treatment solution before the micro-etching rate test reaction of the example or comparative example and the treatment solution after the micro-etching rate test reaction, and continue to control the temperature at 30.0±0.5 ℃ for 48 h. Put them into 250 mL conical flasks, add 50 mL of deionized water and 5 mL of 50% sulfuric acid solution, and titrate with 0.1 mol / L potassium permanganate standard solution until the color changes from colorless to pink as the endpoint. Record the number of milliliters. (3) Calculate the hydrogen peroxide concentration: 35% hydrogen peroxide concentration (g / L) = 0.1 mol / L × number of mL of potassium permanganate standard solution × 4.857; (4) Calculate the hydrogen peroxide decomposition rate η: η = (Hydrogen peroxide concentration before reaction - hydrogen peroxide concentration after reaction) / hydrogen peroxide concentration before reaction × 100%. The test results are shown in Table 1 below.

[0048] 3. Surface Observation: The copper foil samples treated according to the above micro-etching rate test for 48 hours were subjected to surface observation. During imaging, the defects were positioned as close as possible to the focal plane, and the light was projected from above the object downwards. The observation results of the electrolytic copper foil surfaces of Example 1 and Comparative Examples 2 and 7 are as follows: Figure 1-3 As shown.

[0049] 4. Degreasing performance test: The copper foil sample treated according to the above micro-etching rate test was used as the degreasing test substrate. A FLEXART dyne pen with a range of 28mN / m-72mN / m was used to draw evenly on the surface of the treated copper foil. The continuity of the ink line was observed within 10 seconds. If it was continuous, the corresponding dyne value was recorded. If it was discontinuous, the range was reduced and the test was repeated. Each group was tested in parallel 3 times. The evaluation results are shown in Table 1 below.

[0050] 5. Anti-oxidation test: The copper foil sample treated according to the micro-etching rate test above was used as the substrate for the anti-oxidation test. The sample was placed in a constant temperature and humidity chamber with a temperature of 40±2 ℃ and a relative humidity of 60±5%. The sample was taken out every 24 hours to observe the surface condition and the time when the first oxidation discoloration (yellowing, blackening) appeared was recorded (denoted as t0). t0≥120h (5 days) was considered qualified. Each group was tested in parallel 3 times, and the shortest oxidation time was recorded as the first oxidation time. The test results are shown in Table 1 below.

[0051] 6. Micro-etching uniformity: The copper foil sample treated according to the above micro-etching rate test was used as the evaluation sample. Nine areas were taken from the surface of the copper foil sample after treatment for copper thickness testing (instrument: CMI700 thickness measuring instrument). The evaluation method is as follows: take copper foil and measure the copper thickness at 3 x 3 = 9 points respectively; AVG: average copper thickness at 9 points; MAX: maximum copper thickness at 9 points; MIN: minimum copper thickness at 9 points; Range: MAX - MIN; σ: standard deviation; Etching amount: average copper thickness before etching - average copper thickness after etching; Uniformity: (1 - 3 × σ / etching amount) × 100%; The evaluation results are shown in Table 1 below.

[0052] 7. Environmental indicators of the treated solutions from Examples 1-11 were tested. The COD values ​​were determined according to GB / T 11914-1989 "Determination of Chemical Oxygen Demand in Water - Dichromate Method". The results showed that all COD values ​​were ≤80 mg / L and no heavy metal ions were detected, which met the environmental protection requirements.

[0053] Table 1 - Performance test results of the treatment solutions in the embodiments and comparative examples of this application As shown in Table 1, the treatment solutions prepared in Examples 1-11 can effectively achieve integrated micro-etching, degreasing, and anti-oxidation treatment, resulting in copper surfaces that appear smooth after treatment. Figure 1 As shown, no copper surface oxidation was observed, and the copper surface was uniformly micro-etched with no fingerprints or oil residue.

[0054] As shown in Table 1, compared with Example 1, Comparative Example 1 did not add surfactant, resulting in a copper surface dyne value of only 32mN / m after micro-etching, compared with the dyne value of 50mN / m in Example 1. The surface cleanliness was greatly reduced, and the uniformity of the copper surface after micro-etching was only 50%, indicating uneven micro-etching of the copper surface.

[0055] As shown in Table 1, Figure 2 As shown, Comparative Example 2 did not contain any azole antioxidants, and therefore could not form a dense and long-lasting antioxidant protective layer on the copper surface, resulting in oxidation and discoloration of the copper surface within 2 hours. In contrast, Example 1 did not experience oxidation within 5 days.

[0056] As shown in Table 1, Comparative Example 3 did not contain any stabilizer, which led to a sharp decline in the stability of the micro-etching solution, with a hydrogen peroxide decomposition rate of 90%. This demonstrates that stabilizers are essential for maintaining a long-term stable micro-etching environment for complexed metal ions.

[0057] As shown in Table 1, no accelerator was added to Comparative Example 4, which resulted in a micro-etching rate of 3.0 μm / min. The low micro-etching rate greatly reduced the micro-etching efficiency, leading to excessively long processing time and affecting the processing efficiency.

[0058] As shown in Table 1, Comparative Example 5 used Tween-80 as a surfactant in its treatment solution, while Comparative Example 6 used hexadecyltrimethylammonium bromide as a surfactant. This resulted in a decrease in the micro-etching efficiency of the treatment solution, and the uniformity of micro-etching on the copper surface after treatment was only 49%-52%, which was significantly lower than the 80% in Example 1. Furthermore, the dyne value of the copper surface after micro-etching in Comparative Example 5 was only 30 mN / m, compared to the 50 mN / m in Example 1, indicating a significant reduction in surface cleanliness.

[0059] Compared to Example 1, Comparative Example 7 used antioxidant BHT to replace the azole antioxidant component. The antioxidant function of BHT was completely lost; it could not coordinate with the copper surface to form an antioxidant protective layer. Figure 3 As shown, severe oxidation occurs on the copper surface.

[0060] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A copper surface treatment liquid, characterized by comprising: The copper surface treatment liquid comprises the following components by weight parts 100: The base micro-etching component: 8-15 parts; The surfactant: 5-12 parts; The azole oxygen-proof component: 1-4 parts; The stabilizer: 3-7 parts; The accelerator: 0.1-10 parts; Water: the balance; The surfactant is at least one of fatty alcohol polyoxyethylene ether, sodium dodecyl benzene sulfonate and cocamide propyl betaine; the azole oxygen-proof component comprises at least one of benzotriazole, methyl benzotriazole and mercaptobenzothiazole.

2. The copper surface treatment liquid according to claim 1, wherein The base micro-etching component comprises sulfuric acid and hydrogen peroxide.

3. The copper surface treatment liquid according to claim 2, wherein The sulfuric acid component is 1-14 parts and the hydrogen peroxide component is 1-7 parts by weight parts 100 of the copper surface treatment liquid.

4. The copper surface treatment liquid according to claim 1 or 2, wherein The surfactant comprises fatty alcohol polyoxyethylene ether and sodium dodecyl benzene sulfonate with a mass ratio of (1-3):

1.

5. The copper surface treatment liquid according to claim 1 or 2, wherein The stabilizer comprises at least one of p-hydroxybenzoic acid, sodium gluconate, disodium EDTA and sodium citrate.

6. The copper surface treatment liquid according to claim 1 or 2, wherein The accelerator is at least one of triethanolamine, sodium hydroxymethyl sulfonate and polyethylene glycol 400.

7. The copper surface treatment liquid according to claim 5, wherein The stabilizer comprises p-hydroxybenzoic acid and / or sodium gluconate.

8. A method for producing the copper surface treatment liquid according to any one of claims 2 to 7, characterized by, The copper surface treatment liquid is prepared by the following steps: first, adding at least half of the water and all of the sulfuric acid, stirring and mixing, cooling to room temperature, then adding the surfactant, the azole oxygen-proof component, the stabilizer and the accelerator, stirring and mixing uniformly, subsequently adding the hydrogen peroxide, and finally adding the remaining water, stirring and mixing uniformly.

9. The copper surface treatment liquid according to any one of claims 1-8 for use in micro-etching treatment of the copper surface of a printed circuit board.

10. The use of the copper surface treatment liquid according to claim 9 in the microetching treatment of the copper surface of a printed wiring board, characterized in that, The printed circuit board copper surface is immersed in a constant temperature water bath at 25-35 ℃ for 0.5-1.5 min, taken out, washed and dried to complete the micro-etching treatment. The printed circuit board copper surface is immersed in a constant temperature water bath at 25-35 ℃ for 0.5-1.5 min, taken out, washed and dried to complete the micro-etching treatment.

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