Copper surface micro-etching coarsening solution for fine circuit as well as preparation method and application of copper surface micro-etching coarsening solution

Abstract

The invention discloses a copper surface micro-etching coarsening solution for a fine circuit as well as a preparation method and application of the copper surface micro-etching coarsening solution, and relates to the technical field of printed circuit board manufacturing. The copper surface micro-etching coarsening solution for the fine circuit is prepared from, by mass concentration, 60 g / L to 100 g / L of sulfuric acid, 40 g / L to 60 g / L of hydrogen peroxide, 0.5 g / L to 2 g / L of zinc sulfate, 10 g / L to 30 g / L of copper ions, 0.5 g / L to 1 g / L of pyridine heterocycle-containing Schiff base, 10 g / L to 100 g / L of ethyl alcohol, 1 g / L to 3 g / L of 2-mercaptobenzothiazole, 1 g / L to 5 g / L of methionine and 1 g / L to 5 g / L of polyacrylamide. According to the copper surface micro-etching coarsening solution, the 2-mercaptobenzothiazole and the methionine in the copper surface micro-etching coarsening solution can enable the copper surface to form a honeycomb structure under the low micro-etching amount, the zinc sulfate and the pyridine heterocyclic ring-containing Schiff base can form a composite film layer with copper ions on the surface of the honeycomb structure, and the interlayer binding force is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printed circuit board manufacturing, and particularly relates to a copper surface micro-etching and roughening solution for fine lines, and a preparation method and application thereof. BACKGROUND

[0002] In the manufacturing process of printed circuit boards (PCB), in order to ensure that the copper surface has stable bonding force with the subsequently attached resist film or etching film, the copper surface needs to be pretreated before the film attaching process. At present, the industry adopts differentiated copper surface treatment processes for PCBs of different grades: low-grade printed circuit boards usually adopt mechanical grinding or traditional chemical micro-etching process. Although such process has low cost, the roughening effect is limited, the copper surface area is not significantly increased, and it is difficult to meet the demand for high bonding force; medium and high-grade printed circuit boards generally adopt copper surface micro-etching and roughening process. This process can form a honeycomb-like rough structure on the copper surface, significantly increase the copper surface area, and greatly improve the adhesion of the film layer to the copper surface. It is a key process for ensuring the quality of medium and high-grade PCB products.

[0003] With the rapid development of consumer electronic products towards miniaturization, portability and multifunction, PCB products continue to evolve towards high-density wiring, high speed and high frequency. The line width / line spacing (L / S) of fine printed circuit boards such as HDI / BUM boards has developed from the traditional 50μm / 50μm to 30μm / 30μm or even finer specifications. In the process of manufacturing fine printed circuit boards, due to the significant reduction of line width / line spacing (L / S), the actual contact area between the film layer and the copper surface is significantly reduced, which puts higher requirements on the bonding force between the copper surface and the film layer.

[0004] Traditional copper surface micro-etching and roughening solution generally follows the logic that "the greater the etching amount, the better the roughening effect, and the stronger the bonding force". In order to achieve better roughening effect, the micro-etching amount is generally controlled at 1-2μm. However, after treating the copper surface with a larger micro-etching amount, it is easy to cause problems such as line thinning (line thinning), open circuit, or impedance increase due to change of line cross-sectional shape in subsequent fine line processing. And the narrower the line width and line spacing, the more prominent the above problems: for PCBs with line width / line spacing of 50μm / 50μm or more, the impact of the large micro-etching amount of the traditional micro-etching and roughening solution can be partially offset by adjusting the process parameters of the subsequent process, and it can still meet the batch production requirements; but for fine lines with line width / line spacing of 30μm / 30μm or less, the excessive micro-etching amount of the traditional micro-etching and roughening solution will directly affect the integrity of the line pattern, resulting in a decrease in product yield and unstable characteristic impedance, which cannot meet the production requirements of fine line PCBs. Therefore, developing a copper surface micro-etching and roughening solution with low etching amount and high bonding force has become the key to solving the current industry pain points. SUMMARY

[0005] To solve the above technical problems, the application provides a copper surface micro-etching and roughening solution for fine lines, a preparation method and application thereof, in particular to a copper surface micro-etching and roughening solution for fine lines of high-density interconnection board (HDI), build-up multi-layer board (BUM) and other fine line printed circuit board (PCB) and a preparation method and application thereof.

[0006] Specifically, the technical solutions include the following: In a first aspect, a copper surface micro-etching and roughening solution for fine lines is provided, comprising the following mass concentration components: sulfuric acid 60-100 g / L, hydrogen peroxide 40-60 g / L, zinc sulfate 0.5-2 g / L, copper ions 10-30 g / L, pyridine heterocyclic Schiff base 0.5-1 g / L, ethanol 10-100 g / L, 2-mercaptobenzothiazole 1-3 g / L, methionine 1-5 g / L, and polyacrylamide 1-5 g / L.

[0007] Further, the mass ratio of zinc sulfate to pyridine heterocyclic Schiff base is 1:(0.5-1).

[0008] Further, the copper surface micro-etching and roughening solution for fine lines is composed of the following mass concentration components: sulfuric acid 60-100 g / L, hydrogen peroxide 40-60 g / L, copper ions 10-30 g / L, zinc sulfate 0.5-2 g / L, pyridine heterocyclic Schiff base 0.5-1 g / L, ethanol 10-100 g / L, 2-mercaptobenzothiazole 1-3 g / L, methionine 1-5 g / L, and polyacrylamide 1-5 g / L, with the balance being deionized water.

[0009] Further, the copper surface micro-etching and roughening solution for fine lines is composed of the following mass concentration components: sulfuric acid 60-100 g / L, hydrogen peroxide 40-60 g / L, copper ions 10-30 g / L, zinc sulfate 0.5-1 g / L, pyridine heterocyclic Schiff base 0.5-0.7 g / L, ethanol 10-100 g / L, 2-mercaptobenzothiazole 2-3 g / L, methionine 3-5 g / L, polyacrylamide 1-3 g / L, with the balance being deionized water.

[0010] Further, the copper ions are from copper sulfate pentahydrate or copper oxide; and the pyridine heterocyclic Schiff base is selected from one of o-formylphenoxyacetic acid hydrazones and cinnamaldehyde hydrazones.

[0011] Preferably, the o-formylphenoxyacetic acid condensate with isonicotinoyl hydrazine is a condensate of o-formylphenoxyacetic acid with isonicotinoyl hydrazine, and the cinnamaldehyde condensate with isonicotinoyl hydrazine is a condensate of cinnamaldehyde with isonicotinoyl hydrazine.

[0012] In a second aspect, a preparation method of the copper surface micro-etching and roughening solution for fine lines is provided, comprising the following steps: S1. Take deionized water, and add sulfuric acid under stirring until the sulfuric acid is completely dissolved and the temperature of the solution is reduced to room temperature to obtain a sulfuric acid aqueous solution; S2. Add copper ions, zinc sulfate, a solution containing a pyridine heterocyclic Schiff base, 2-mercaptobenzothiazole, methionine, and polyacrylamide into the sulfuric acid aqueous solution obtained in step S1 in sequence, continuously stir for 15-20 min after each component is added until the component is completely dissolved to obtain a mixed solution; the solution containing the pyridine heterocyclic Schiff base is prepared by stirring and dissolving the pyridine heterocyclic Schiff base in ethanol; S3. Add hydrogen peroxide into the mixed solution obtained in step S2 under stirring, and continue to stir for 30 min to uniformly mix the solution to obtain the copper surface micro-etching and roughening solution for fine lines.

[0013] Further, in step S1, the stirring rate of the stirring condition is 300-500 r / min, and the room temperature is 25±2℃.

[0014] In a third aspect, a copper surface micro-etching and roughening treatment method is provided, in which the copper surface micro-etching and roughening solution for fine lines described in the first aspect is sprayed onto the copper surface of a PCB.

[0015] Further, the spraying mode is horizontal spraying, and the spraying pressure is 2-4 Kg / cm 2 .

[0016] Further, the temperature of the copper surface micro-etching and roughening solution for fine lines is 25-35℃, and the spraying time is 30-60 s.

[0017] Preferably, the copper surface micro-etching and roughening treatment method further comprises the following steps: after the spraying is completed, the copper surface is rinsed with deionized water for 2-3 min, and then dried at 80-90℃ for 2-3 min to complete the copper surface micro-etching and roughening treatment.

[0018] The beneficial effects of the present application are that 2-mercaptobenzothiazole and methionine in the copper surface micro-etching and roughening solution for fine lines can reduce the micro-etching rate of copper, so that the honeycomb structure is formed on the copper surface at a lower micro-etching amount, and zinc sulfate and the pyridine heterocyclic Schiff base can form a composite film layer with copper ions on the surface of the honeycomb structure, which can improve the interlayer bonding force. In addition, the components in the copper surface micro-etching and roughening solution for fine lines can overcome the problem of low yield and fine line defects caused by excessive micro-etching amount in the conventional copper surface micro-etching and roughening solution in the prior art. The micro-etching amount is controlled in the range of 0.3-0.8 μm to achieve the roughening effect, while ensuring the high bonding force between the copper surface and the film layer, and meeting the production requirements of fine line PCB with line width / line spacing of 30 μm / 30 μm or less. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1 SEM image using Example 1 of the present application; Figure 2 SEM image using Comparative Example 2 of the present application. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0022] It should be understood that when used in the specification and the appended claims, the terms "comprise" and "include" indicate the presence of described features, integers, steps, operations, elements, and / or components, but do not exclude one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0023] It should also be understood that the terms used in the present application specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the present application specification and the appended claims, unless otherwise clearly indicated by the context, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0024] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0025] To better understand the technical content of the present invention, the technical solution of the present invention will be further introduced and explained below with reference to specific embodiments.

[0026] In the embodiments / comparative examples of the present invention, the pyridine-containing heterocyclic Schiff base is selected from one of o-formylphenoxyacetic acid acetonitrile and cinnamaldehyde acetonitrile.

[0027] The preparation method of o-formylphenoxyacetic acid isoniazid includes the following steps: dissolving 6 mmol of o-formylphenoxyacetic acid and 7 mmol of isoniazid in 100 mL of anhydrous ethanol, stirring and refluxing magnetically at 35 °C for 1 hour, and obtaining the product after the solvent has evaporated.

[0028] The preparation method of the cinnamaldehyde isoniazid includes the following steps: dissolving 6 mmol of cinnamaldehyde and 7 mmol of isoniazid in 100 mL of anhydrous ethanol, stirring and refluxing magnetically at 35°C for 1 hour, and obtaining the product after the solvent has evaporated.

[0029] Example 1: A copper surface micro-etching and roughening solution for fine circuits comprises the following components by mass concentration: 80 g / L sulfuric acid, 50 g / L hydrogen peroxide, 1 g / L zinc sulfate, 20 g / L copper ions, 0.7 g / L pyridine heterocyclic Schiff base, 50 g / L ethanol, 2 g / L 2-mercaptobenzothiazole, 3 g / L methionine, 3 g / L polyacrylamide, and the balance being deionized water. The copper ions are derived from copper sulfate pentahydrate, and the pyridine heterocyclic Schiff base is o-formylphenoxyacetic acid isoniazid.

[0030] The preparation method of o-formylphenoxyacetic acid isoniazid includes the following steps: 6 mmol of o-formylphenoxyacetic acid and 7 mmol of isoniazid are dissolved in 100 mL of anhydrous ethanol, and the mixture is magnetically stirred and refluxed at 35 °C for 1 hour. After the solvent has evaporated, the product is obtained.

[0031] The preparation method of the copper surface micro-etching roughening solution for fine circuits includes the following steps: S1. Take deionized water and add sulfuric acid under stirring conditions. The stirring rate is 400 r / min. Wait until the sulfuric acid is completely dissolved and the solution temperature drops to room temperature (25℃) to obtain an aqueous sulfuric acid solution. S2. Add copper ions, zinc sulfate, a pyridine heterocyclic Schiff base solution, 2-mercaptobenzothiazole, methionine, and polyacrylamide sequentially to the sulfuric acid aqueous solution obtained in step S1. Stir continuously for 18 minutes after each addition until the component is completely dissolved to obtain a mixed solution. The pyridine heterocyclic Schiff base solution is prepared by dissolving a pyridine heterocyclic Schiff base in ethanol. S3. Under stirring conditions, hydrogen peroxide is added to the mixed solution obtained in step S2, and stirring is continued for 30 minutes to make the solution uniformly mixed, thus obtaining the copper surface micro-etching roughening solution for fine circuits.

[0032] The copper surface micro-etching and roughening solutions for fine circuits in Examples 2-7 were prepared according to the formulations in Table 1 below. The preparation methods for the copper surface micro-etching and roughening solutions for fine circuits in Examples 2-7 were the same as those in Example 1. Table 1. Formulations (mass concentration, g / L) of copper surface micro-etching roughening solutions for fine circuits in Examples 2-7

[0033] In Table 1, the copper ions in Example 4 were provided by copper oxide, and the rest were provided by copper sulfate pentahydrate. The pyridine heterocyclic Schiff bases in Examples 2-4 of Table 1 were all o-formylphenoxyacetic acid isoniazid, and their preparation method was the same as in Example 1. The pyridine heterocyclic Schiff bases in Examples 5-7 of Table 1 were all cinnamaldehyde isoniazid. The preparation method of cinnamaldehyde isoniazid includes the following steps: dissolving 6 mmol of cinnamaldehyde and 7 mmol of isoniazid in 100 mL of anhydrous ethanol, stirring and refluxing magnetically at 35°C for 1 hour, and obtaining the solution after the solvent has evaporated. Comparative Examples 1-7 were prepared according to the formulation of the copper surface micro-etching roughening solution for fine circuits in Table 2 below. The preparation method of the copper surface micro-etching roughening solution for fine circuits in Comparative Examples 1-7 was the same as in Example 1. Table 2 Formulations (mass concentration, g / L) of copper surface micro-etching roughening solutions for fine circuits in Comparative Examples 1-7

[0034] In Table 2, the copper ions in Comparative Example 4 were provided by copper oxide, and the rest were provided by copper sulfate pentahydrate. All pyridine heterocyclic Schiff bases in Table 2 were o-formylphenoxyacetic acid isoniazid, and their preparation method was the same as in Example 1.

[0035] Comparative Examples 8-14 were prepared according to the formulations of the copper surface micro-etching and roughening solutions for fine circuits in Table 3 below. The preparation methods of the copper surface micro-etching and roughening solutions for fine circuits in Comparative Examples 8-14 were the same as those in Example 1. Table 3 Formulations (mass concentration, g / L) of copper surface micro-etching roughening solutions for fine circuits in Comparative Examples 8-14

[0036] In Table 3, the copper ions in Comparative Examples 8-14 were provided by copper sulfate pentahydrate. All pyridine heterocyclic Schiff bases in Table 3 are o-formylphenoxyacetic acid isoniazid, prepared using the same method as in Example 1.

[0037] The fine-line copper surface micro-etching roughening solution of the examples / comparative examples was used to perform copper surface micro-etching roughening treatment. The copper surface micro-etching roughening treatment method includes the following steps: the PCB board to be treated is processed through a horizontal spray pretreatment device according to the factory standard processing procedure. The ultra-roughening tank contains the fine-line copper surface micro-etching roughening solution prepared above. The fine-line copper surface micro-etching roughening solution is sprayed onto the copper surface of the PCB board. The spraying method is horizontal spraying, and the spraying pressure is 3 kg / cm². 2 The temperature of the copper surface micro-etching roughening solution for fine circuits is 30℃, and the spraying time is 40s. After spraying, rinse with deionized water for 2.5min, and then dry at 85℃ for 2.5min to complete the copper surface micro-etching roughening treatment. The test samples are tested according to the following performance test methods.

[0038] Performance testing: 1. Surface morphology: The PCB boards of each embodiment and comparative example were observed with scanning electron microscope. A uniform honeycomb structure was considered acceptable, while a non-uniform or non-honeycomb structure was considered unacceptable. 2. Micro-etching amount test: The weighing method was used: Before micro-etching, the mass of the copper surface area of ​​the PCB board was weighed using an electronic balance (accuracy 0.1 mg) (recorded as m1). After micro-etching, the area was dried to constant weight and weighed again (recorded as m2). Based on the density of copper (8.96 g / cm³) and the area of ​​the copper surface test area (recorded as S), the micro-etching amount was calculated using the formula "micro-etching amount = (m1 - m2) / (ρ × S)". A micro-etching amount of 0.3-0.8 μm is considered acceptable. 3. Bonding strength test: The processed PCB board is laminated with film, and exposed and developed according to L / S=25μm / 25μm to create patterns. 3M tape (model 610) is applied to the dry film of the circuit and quickly peeled off. The film peeling is observed and rated as "0 level (no peeling) - 5 level (complete peeling)", with 0 level being the best. 4. Line Defect Statistics: For each embodiment and comparative example, 5 PCB boards were processed. After the circuit was completed, an optical inspection (AOI) instrument was used to perform a full inspection to count the number of open circuits and thin spots, requiring the number of defect points to be 0.

[0039] The fine circuits from Examples 1-7 were subjected to copper surface micro-etching roughening treatment using the copper surface micro-etching roughening solution, followed by performance testing. The test results are shown in Table 4 below. Table 4 Performance test results of copper surface micro-etching roughening solutions for fine circuits in Examples 1-7

[0040] in, Figure 1 The SEM image used in Embodiment 1 of the present invention. From Figure 1 As shown in Table 4, the copper surface micro-etching roughening solution for fine circuits in this embodiment of the invention performs well, with surface morphology, micro-etching amount, adhesion test, and circuit defect points all within the qualified range.

[0041] The fine lines in Comparative Examples 1-7 were roughened using a copper surface micro-etching roughening solution, and then their performance was tested. The test results are shown in Table 5 below: Table 5 Performance test results of copper surface micro-etching roughening solutions for fine circuits in Comparative Examples 1-7

[0042] in, Figure 2 SEM images of Comparative Example 2 using the present invention. (By...) Figure 2 As shown in Table 5, the copper surface etching and roughening solution for fine circuits prepared without zinc sulfate and a pyridine heterocyclic Schiff base (Comparative Example 1) showed poor adhesion and circuit defect statistics in performance testing. The copper surface etching and roughening solutions for fine circuits prepared with sulfuric acid and hydrogen peroxide at concentrations outside the limits of this invention (Comparative Examples 2 and 3) showed poor surface morphology and circuit defect statistics in performance testing. Furthermore, the copper surface etching and roughening solution for fine circuits prepared using copper ions outside the concentration limits of this invention (Comparative Example 4) showed poor surface morphology in performance testing. The copper surface etching and roughening solution for fine circuits prepared using zinc sulfate and a pyridine heterocyclic Schiff base outside the concentration limits of this invention (Comparative Example 5) showed poor adhesion in performance testing. Furthermore, if 2-mercaptobenzothiazole and methionine, which are not within the mass concentration range specified in this invention, are used, the resulting copper surface micro-etching roughening solution for fine circuits (Comparative Example 6) exhibits poor surface morphology and circuit defect statistics in performance testing. If polyacrylamide, which is not within the mass concentration range specified in this invention, is used, the resulting copper surface micro-etching roughening solution for fine circuits (Comparative Example 7) exhibits poor surface morphology and circuit defect statistics in performance testing.

[0043] The fine lines of Comparative Examples 8-14 were roughened using a copper surface micro-etching solution, and then their performance was tested. The test results are shown in Table 6 below. Table 6 Performance test results of the copper surface micro-etching roughening solution for fine circuits in Comparative Examples 8-14

[0044] As shown in Table 6, the performance test results of the fine-line copper surface etching roughening solution (Comparative Example 8) prepared without 2-mercaptobenzothiazole were all poor. The surface morphology, adhesion, and circuit defect statistics of the fine-line copper surface etching roughening solution prepared without methionine (Comparative Example 9) were also poor. The adhesion and circuit defect statistics of the fine-line copper surface etching roughening solution prepared without zinc sulfate (Comparative Example 10) were also poor. The adhesion test results of the fine-line copper surface etching roughening solution prepared without pyridine heterocyclic Schiff bases (Comparative Example 11) were also poor. Furthermore, the circuit defect statistics of the fine-line copper surface etching roughening solution prepared using a pyridine heterocyclic Schiff base outside the mass concentration range specified in this invention (Comparative Example 12) were also poor. If 2-mercaptobenzothiazole, which is outside the mass concentration range specified in this invention, is used, the resulting copper surface micro-etching roughening solution for fine circuits (Comparative Example 13) exhibits poor surface morphology and circuit defect statistics in performance testing. If the mass ratio of zinc sulfate to a pyridine heterocyclic Schiff base is outside the range specified in this invention, the resulting copper surface micro-etching roughening solution for fine circuits (Comparative Example 14) exhibits poor circuit defect statistics in performance testing.

[0045] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A copper surface micro-etching roughening solution for fine circuits, characterized in that, It includes the following components in mass concentration: sulfuric acid 60-100 g / L, hydrogen peroxide 40-60 g / L, zinc sulfate 0.5-2 g / L, copper ions 10-30 g / L, pyridine-containing heterocyclic Schiff base 0.5-1 g / L, ethanol 10-100 g / L, 2-mercaptobenzothiazole 1-3 g / L, methionine 1-5 g / L, and polyacrylamide 1-5 g / L.

2. The copper surface micro-etching and roughening solution for fine circuits as described in claim 1, characterized in that, The mass ratio of zinc sulfate to pyridine heterocyclic Schiff base is 1:(0.5-1).

3. The copper surface micro-etching and roughening solution for fine circuits as described in claim 1, characterized in that, It consists of the following components in mass concentration: sulfuric acid 60-100 g / L, hydrogen peroxide 40-60 g / L, copper ions 10-30 g / L, zinc sulfate 0.5-2 g / L, pyridine heterocyclic Schiff base 0.5-1 g / L, ethanol 10-100 g / L, 2-mercaptobenzothiazole 1-3 g / L, methionine 1-5 g / L, polyacrylamide 1-5 g / L, with the balance being deionized water.

4. The copper surface micro-etching and roughening solution for fine circuits as described in claim 3, characterized in that, It consists of the following components in mass concentration: sulfuric acid 60-100 g / L, hydrogen peroxide 40-60 g / L, copper ions 10-30 g / L, zinc sulfate 0.5-1 g / L, pyridine heterocyclic Schiff base 0.5-0.7 g / L, ethanol 10-100 g / L, 2-mercaptobenzothiazole 2-3 g / L, methionine 3-5 g / L, polyacrylamide 1-3 g / L, with the balance being deionized water.

5. The copper surface micro-etching and roughening solution for fine circuits as described in claim 1, characterized in that, The copper ions are derived from copper sulfate pentahydrate or copper oxide; the pyridine-containing heterocyclic Schiff base is selected from o-formylphenoxyacetic acid isoniazid or cinnamaldehyde isoniazid.

6. The method for preparing the copper surface micro-etching roughening solution for fine circuits as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Take deionized water, add sulfuric acid under stirring, and wait for the sulfuric acid to completely dissolve and the solution temperature to drop to room temperature to obtain an aqueous sulfuric acid solution; S2. Add copper ions, zinc sulfate, a pyridine heterocyclic Schiff base solution, 2-mercaptobenzothiazole, methionine, and polyacrylamide sequentially to the sulfuric acid aqueous solution obtained in step S1. After each component is added, stir continuously for 15-20 minutes until the component is completely dissolved to obtain a mixed solution. The pyridine heterocyclic Schiff base solution is prepared by dissolving a pyridine heterocyclic Schiff base in ethanol. S3. Under stirring conditions, hydrogen peroxide is added to the mixed solution obtained in step S2, and stirring is continued for 30 minutes to make the solution uniformly mixed, thus obtaining the copper surface micro-etching roughening solution for fine circuits.

7. The method for preparing the copper surface micro-etching roughening solution for fine circuits as described in claim 6, characterized in that, In step S1, the stirring rate of the stirring conditions is 300-500 r / min, and the room temperature is 25±2℃.

8. A method for roughening copper surface through micro-etching, characterized in that, The fine-line copper surface micro-etching roughening solution described in any one of claims 1-6 is sprayed onto the copper surface of the PCB board.

9. The copper surface micro-etching roughening treatment method as described in claim 8, characterized in that, The spraying method is horizontal spraying, and the spraying pressure is 2-4 kg / cm². 2 .

10. The copper surface micro-etching roughening treatment method as described in claim 8, characterized in that, The temperature of the copper surface micro-etching roughening solution for fine circuits is 25-35℃, and the spraying time is 30-60s.

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