A stable and uniform chemical micro-etching method

Abstract

The present application relates to the field of electronic material processing, and specifically discloses a stable and uniform chemical micro-etching method, comprising the following steps: S1, pre-treating a metal substrate to obtain a pre-treated substrate; S2, first spraying a micro-etching agent A containing sodium persulfate on the substrate through an HVLP spraying process, and then washing with water to obtain a primary micro-etching substrate; S3, soaking the primary micro-etching substrate prepared in step S2 in a micro-etching agent B containing dilute acid and microcapsule particles containing 8-hydroxyquinoline, rinsing and drying, and obtaining a substrate B; S4, soaking the substrate B prepared in step S3 in a micro-etching agent C containing polyethyleneimine, nano-graphene oxide, and hydroxypropyl β-cyclodextrin-coated tea saponin, rinsing and drying, and obtaining a micro-etching substrate. The present application has the characteristics of providing a stable and uniform chemical micro-etching method to improve the uniform corrosion of the material surface and improve the surface quality of the material.

Description

Technical Field

[0001] The present invention relates to the field of electronic material processing, and more particularly to a stable and uniform chemical micro-etching method. Background Art

[0002] Chemical micro-etching technology is a technology that uses the principle of chemical reaction to produce tiny corrosion pits or corrosion grooves on the metal surface to achieve the regulation and modification of the microscopic morphology of the metal surface. In the field of material surface treatment, micro-etching technology is widely used to improve the performance of material surfaces.

[0003] For example, a Chinese patent application with application publication number CN110791788 discloses a method and system for electroplating a light-emitting diode bracket and between light-emitting diodes. The electroplating method includes: micro-etching the bracket to remove the oxide layer on the surface of the bracket and activate the surface of the bracket; impact nickel electroplating the bracket to form a first electroplated nickel layer on the surface of the bracket; alkaline copper plating the bracket to form an electroplated copper layer on the first electroplated nickel layer; silver plating the bracket to form an electroplated silver layer on the second electroplated layer.

[0004] Another example is the etching EMC nickel-palladium-gold series, which means depositing metal layers of nickel, palladium and gold on the copper layer surface of the circuit board by chemical or physical methods. The main process flow for the preparation of this series of products includes degreasing, micro-etching, pre-impregnation, activation, nickel deposition, palladium deposition, gold deposition and drying. Before the metal layer of the above-mentioned electronic products is plated, a micro-etching process will be performed first to effectively remove impurities, oxides and other residues on the surface of the material. It can also form fine concave and convex shapes on the surface of the material, thereby roughening its surface. The micro-etching reaction is used for copper surface treatment of microelectronic products and components.

[0005] Although chemical micro-corrosion technology has broad application prospects, it still faces some challenges in its actual application. Currently, most chemical corrosion methods use immersion or spraying methods. These methods are difficult to ensure the uniformity and stability of corrosion. There are problems such as uneven corrosion, difficult to control the speed, and possible damage to the material matrix, which seriously affects the final performance and service life of the material.

[0006] Therefore, providing a stable and uniform chemical micro-etching method is of great significance for achieving uniform corrosion of the material surface and improving the surface quality of the material. Summary of the invention

[0007] In order to provide a stable and uniform chemical micro-etching method to improve the uniform corrosion of the material surface and improve the surface quality of the material, the present application provides a stable and uniform chemical micro-etching method.

[0008] In the first aspect, the present application provides a stable and uniform chemical micro-etching method, which adopts the following technical solution: A stable and uniform chemical micro-etching method comprises the following steps: S1, pretreating the metal substrate to obtain a pretreated substrate; S2, spraying the micro-etching agent A containing sodium persulfate onto the substrate by HVLP spraying process, and then washing with water to obtain the initial micro-etching substrate; S3, soaking the initial micro-etching substrate prepared in step S2 in a micro-etching agent B containing dilute acid and microcapsule particles containing 8-hydroxyquinoline, rinsing and drying, to obtain a substrate B; S4, soaking the substrate B prepared in step S3 in a micro-etching agent C containing polyethyleneimine, nano-graphene oxide and hydroxypropyl β-cyclodextrin-coated tea saponin, rinsing and drying, to obtain a micro-etching substrate.

[0009] By adopting the above technical scheme, the present application adopts a multi-step micro-etching treatment process, and each step uses a different micro-etching liquid. By gradually adjusting the surface properties of the substrate, a more stable and uniform micro-etching effect is gradually achieved. In the present application, the micro-etching agent A containing sodium persulfate is first treated. Sodium persulfate, as a strong oxidant, reacts with impurities such as oxides on the metal surface to generate soluble metal sulfates and water. The oxides on the metal surface are removed after rinsing. At the same time, it can also react with impurities such as grease and dirt on the metal surface to decompose them so that they are washed away. In addition, sodium persulfate can also react with the metal itself to form tiny corrosion pits to achieve micro-etching of the substrate. In combination with the treatment process of the HVLP spraying process in the present application, the sodium persulfate micro-etching agent A is sprayed on the metal surface in a high-speed and uniform manner. This physical impact also helps to loosen and remove the attachments on the metal surface, including oxides and dirt. In the present application, a strong oxidant and an HVLP spraying process are first used to achieve short-term and efficient corrosion of the substrate, remove surface impurities and form small corrosion pits, and achieve preliminary uniform micro-etching; Then, the metal is immersed in a micro-etching agent B containing a dilute acid and microcapsule particles containing 8-hydroxyquinoline. The dilute acid can continue to react with the metal surface to remove the remaining oxides and impurities, while promoting uniform corrosion of the metal surface. 8-Hydroxyquinoline, as a chelating agent, contains a hydroxyl group, and forms a chelate with the metal salt or impurity metal formed in the treatment solution and then removes it, and can also slow down the corrosion rate. The addition of microcapsule particles ensures the uniform distribution and slow release of 8-hydroxyquinoline on the metal surface, thereby improving the stability and uniformity of the micro-etching treatment. Finally, it is treated in a micro-etching agent C containing polyethyleneimine, nano-graphene oxide and hydroxypropyl β-cyclodextrin coated tea saponin. Nano-graphene oxide has a strong adsorption capacity, can adsorb and remove impurities on the surface of the substrate, and can form a stable protective layer. Tea saponin, as a surfactant, can reduce the surface tension of the solution, making it easier for the micro-etching agent C to penetrate into the tiny gaps on the metal surface, thereby achieving a more uniform corrosion effect. Tea saponin also has a corrosion inhibition effect to prevent excessive corrosion of the metal surface of the substrate. Tea saponin has a low solubility in water at room temperature. Therefore, in this application, hydroxypropyl β-cyclodextrin is used to coat tea saponin and then added. Hydroxypropyl β-cyclodextrin has a cavity structure with internal lipophilicity and external hydrophilicity. After tea saponin is coated with it, its water solubility in water is improved. On the one hand, it is more conducive to its sustained release and surfactant effects, and on the other hand, it is more conducive to subsequent removal. Moreover, hydroxypropyl β-cyclodextrin itself can also play a corrosion inhibition role, and finally the micro-corrosion rate is adjusted to achieve a stable and uniform micro-etching effect.

[0010] Finally, in this application, the substrate is processed in multiple steps and under different processing conditions to achieve stable and uniform micro-corrosion of the substrate. On the one hand, oxides and other impurities on the surface of the substrate are removed, and on the other hand, fine concave and convex shapes are formed on the surface of the material, thereby roughening its surface and achieving micro-regulation of the metal surface of the substrate.

[0011] Optionally, the micro-etching agent A in step S2 includes the following raw materials in percentage by mass: Sodium persulfate 35-45%, sulfuric acid 5-10%, sodium chloride 10-15%, ethanol 5-10% and the balance water.

[0012] Optionally, the micro-etching agent B in step S3 includes the following raw materials in percentage by mass: 40-50% of dilute acid, 20-30% of microcapsule particles containing 8-hydroxyquinoline, 0.5-1.5% of 2-hydroxy-N,N,N-trimethylethylamine tetrafluoroborate, 1-3% of disodium hydrogen phosphate and the balance of water.

[0013] By adopting the above technical scheme, in the micro-etching agent B of the present application, on the basis of adding dilute acid and microcapsule particles containing 8-hydroxyquinoline, a small amount of ionic liquid 2-hydroxy-N, N, N-trimethylethylamine tetrafluoroborate and stabilizer disodium hydrogen phosphate are also added. It is found that the addition of 2-hydroxy-N, N, N-trimethylethylamine tetrafluoroborate ionic liquid plays an important role in maintaining stable and uniform micro-etching, greatly improving the stability and uniformity of micro-etching.

[0014] Optionally, the microcapsule particles containing 8-hydroxyquinoline are prepared by the following method: Dissolve 8-hydroxyquinoline in 3-4 times the mass of ethanol to form a core material solution; Dissolving chitosan in 2-3 times the mass concentration of 30-40% acetic acid solution to form a wall material solution; The prepared core material solution is added to the wall material solution, and then Tween is added, and formaldehyde is added after stirring, and then ammonium bicarbonate is added to adjust the pH to 8, and solidified to form a microcapsule structure, filtered, washed with water, and dried to obtain microcapsule particles; The mass ratio of 8-hydroxyquinoline to chitosan is 1:(0.6-0.8), the amount of Tween added is 3-5% of the weight of the core solution, and the amount of formaldehyde added is 1-3wt% of the amount of chitosan added.

[0015] By adopting the above technical scheme, 8-hydroxyquinoline is first dissolved in ethanol to form a core material solution, and chitosan is dissolved in an acidic solution to form a wall material solution, and then the two are mixed. Under the action of formaldehyde as a cross-linking agent, a cross-linked structure is formed between chitosans to form a more stable wall material structure. The pH is adjusted to alkaline conditions so that chitosan precipitates to form a wall material, thereby achieving the inclusion of 8-hydroxyquinoline. The pH value is adjusted to alkaline so that ammonium bicarbonate is excessive and forms a wall material structure together with chitosan. Then, in the subsequent washing and drying process, ammonium bicarbonate is dissolved in water and volatilized to form a porous slow-release structure, thereby achieving a slow-release mechanism of 8-hydroxyquinoline, so that when treated in the micro-etching agent B, the slow-release contributes to continuous and stable release, thereby contributing to maintaining a long-term corrosion inhibition protection effect, further contributing to the stability and uniformity of the micro-corrosion process, and contributing to obtaining a more uniform and detailed corrosion inhibition effect.

[0016] Optionally, the dilute acid in step S2 includes one or more of hydrofluoric acid, acetic acid, and citric acid.

[0017] Optionally, the micro-etching agent C in step S3 includes the following raw materials in weight percentage: Polyethyleneimine 20-30%, nano graphene oxide 10-20%, hydroxypropyl beta-cyclodextrin-encapsulated tea saponin 15-25%, triethanolamine 5-10% and the balance water.

[0018] By adopting the above technical scheme, during the final micro-etching treatment, the addition of triethanolamine in the micro-etching agent helps to remove residues and pollutants, ensuring the cleanliness of the metal surface and the quality of micro-etching. Tea saponin acts as a surfactant to help further remove them, and coating it with cyclodextrin helps to improve its water solubility, which is more conducive to the removal of pollutants. In addition, the final polyethyleneimine concentration is low, which plays a final improvement and cleaning role in micro-etching. Finally, after multi-step treatment with different micro-etching agents of this application, while ensuring the micro-etching results, more importantly, the stable and uniform occurrence of micro-etching is guaranteed.

[0019] Optionally, hydroxypropyl β-cyclodextrin is used to coat tea saponin by the following method: Hydroxypropyl β-cyclodextrin and water are mixed in a mass ratio of 1:(3-4) to obtain a wall material solution, and then the wall material solution is spray-dried on the surface of tea saponin to obtain hydroxypropyl β-cyclodextrin-coated tea saponin, wherein the added mass ratio of the wall material solution to tea saponin is 1:(1-1.2).

[0020] By adopting the above technical solution and the above method, the coating of tea saponin by hydroxypropyl β-cyclodextrin is achieved in a simpler and more convenient manner.

[0021] Optionally, during the HVLP spraying process in step S2, the spraying distance is 20-25 cm, the spraying air inlet pressure is 1.0-2.0 bar, the atomization pressure of the hood is 0.3-0.5 bar, and the compressed air flow rate is 20-25 cfm.

[0022] By adopting the above technical solution and using the above parameters to atomize and spray the micro-etching agent using high-flow, low-pressure compressed air, the micro-etching agent can be more evenly distributed on the substrate surface during the spraying process, forming a more stable and uniform micro-etching.

[0023] Optionally, the specific operation of the metal substrate surface pretreatment in step S1 is: cleaning and degreasing the substrate and then cleaning and drying it to obtain a pretreated substrate.

[0024] Optionally, in step S4, after the substrate B is immersed in the micro-etching agent C and then rinsed and dried, it is first heated to 250-280° C. in a nitrogen atmosphere, kept warm for 20-30 minutes, then heated to 400-450° C., kept warm for 40-60 minutes, and then cooled to room temperature to obtain a micro-etching substrate.

[0025] By adopting the above technical solution, in the present application, the substrate is first pre-treated with oil removal to facilitate the subsequent micro-etching process, and then the micro-etching treatment is combined with heat treatment in a nitrogen atmosphere to further improve the stability and corrosion uniformity of the substrate.

[0026] In summary, this application has the following beneficial effects: 1. In the present application, the micro-etching agent A containing sodium persulfate is first used for treatment, and then the micro-etching agent B containing dilute acid and microcapsule particles containing 8-hydroxyquinoline is immersed for treatment, and finally the micro-etching agent C containing polyethyleneimine, nano-graphene oxide and hydroxypropyl β-cyclodextrin coated tea saponin is used for treatment. A multi-step micro-etching treatment process is adopted, and different micro-etching liquids are used in each step. By gradually adjusting the surface properties of the substrate, a more stable and uniform micro-etching effect is gradually achieved; 2. In the present application, the micro-etching agent A containing sodium persulfate is first used for treatment, and then the HVLP spraying process in the present application is used for treatment, so that the sodium persulfate micro-etching agent A is sprayed on the metal surface in a high-speed and uniform manner. This physical impact also helps to loosen and remove the attachments on the metal surface, including oxides and dirt. In the present application, a strong oxidant and HVLP spraying process are first used to achieve short-term and efficient corrosion of the substrate, remove surface impurities and form small corrosion pits, and achieve preliminary uniform micro-etching; 3. In the microetching agent B of the present application, in addition to the addition of dilute acid and microcapsule particles containing 8-hydroxyquinoline, a small amount of ionic liquid 2-hydroxy-N,N,N-trimethylethylamine tetrafluoroborate and stabilizer disodium hydrogen phosphate are also added. It is found that the addition of 2-hydroxy-N,N,N-trimethylethylamine tetrafluoroborate ionic liquid plays an important role in maintaining stable and uniform micro-corrosion, greatly improving the stability and uniformity of micro-corrosion. DETAILED DESCRIPTION

[0027] The present application is further described in detail below in conjunction with the examples. It is particularly noted that if no specific conditions are specified in the following examples, the experiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0028] The degreasing agent in the following embodiments is an industrial metal degreasing agent with a brand of Changshui produced by Shandong Changshui Environmental Protection Technology Co., Ltd.

[0029] The following preparation example is an example of the preparation of microcapsule particles containing 8-hydroxyquinoline: Preparation Example 1 A method for preparing microcapsule particles containing 8-hydroxyquinoline comprises the following steps: 1) Dissolve 8-hydroxyquinoline in 3.5 times the mass of ethanol to form a core material solution; 2) dissolving chitosan in 2.5 times the mass concentration of 35% acetic acid solution to form a wall material solution; 3) Add the prepared core material solution to the wall material solution, then add Tween-60, add formaldehyde after stirring, then add ammonium bicarbonate to adjust the pH to 8, solidify to form a microcapsule structure, filter, wash with water, and dry to obtain microcapsule particles; The mass ratio of 8-hydroxyquinoline to chitosan is 1:0.7, the amount of Tween-60 added is 4% of the weight of the core material solution, and the amount of formaldehyde added is 2wt% of the amount of chitosan added.

[0030] Preparation Example 2 A method for preparing microcapsule particles containing 8-hydroxyquinoline comprises the following steps: 1) Dissolve 8-hydroxyquinoline in 3 times the mass of ethanol to form a core material solution; 2) dissolving chitosan in 2 times the mass concentration of 30% acetic acid solution to form a wall material solution; 3) Add the prepared core material solution to the wall material solution, then add Tween-60, add formaldehyde after stirring, then add ammonium bicarbonate to adjust the pH to 8, solidify to form a microcapsule structure, filter, wash with water, and dry to obtain microcapsule particles; The mass ratio of 8-hydroxyquinoline to chitosan is 1:0.6, the amount of Tween-60 added is 3% of the weight of the core material solution, and the amount of formaldehyde added is 1wt% of the amount of chitosan added.

[0031] Preparation Example 3 A method for preparing microcapsule particles containing 8-hydroxyquinoline comprises the following steps: 1) Dissolve 8-hydroxyquinoline in 4 times the mass of ethanol to form a core material solution; 2) dissolving chitosan in 3 times the mass concentration of 40% acetic acid solution to form a wall material solution; 3) Add the prepared core material solution to the wall material solution, then add Tween-60, add formaldehyde after stirring, then add ammonium bicarbonate to adjust the pH to 8, solidify to form a microcapsule structure, filter, wash with water, and dry to obtain microcapsule particles; The mass ratio of 8-hydroxyquinoline to chitosan is 1:0.8, the amount of Tween-60 added is 5% of the weight of the core material solution, and the amount of formaldehyde added is 3wt% of the amount of chitosan added.

[0032] Example 1 A stable and uniform chemical micro-etching method comprises the following steps: S1, cleaning the metal substrate copper plate, and then degreasing it with a degreasing agent to obtain a pretreated substrate; S2. Add the raw materials according to the following mass percentages to mix and prepare 1 kg of micro-etching agent A: Sodium persulfate 40%, sulfuric acid 8%, sodium chloride 12%, ethanol 8% and the balance water; The micro-etching agent A prepared above is diluted by 10 times by mass and then sprayed on the substrate through HVLP spraying process, and then washed with water to obtain a primary micro-etching substrate; The HVLP spraying process parameters are: spraying distance 22cm, spraying air inlet pressure 1.5bar, atomization pressure of the hood 0.4bar, compressed air flow 22cfm, and spraying amount of micro-etching agent A 0.2g / cm 2 ; S3. Prepare 1 kg of micro-etching agent B by mixing the following raw materials in the following mass percentages: 45% citric acid, 25% of the microcapsule particles containing 8-hydroxyquinoline prepared in Preparation Example 1, 1.0% of 2-hydroxy-N,N,N-trimethylethylamine tetrafluoroborate and 2% of disodium hydrogen phosphate and the balance of water; After diluting the micro-etching agent B with water at a mass ratio of 1:30, the initial micro-etching substrate prepared in step S2 is immersed in the micro-etching agent B prepared by mixing for 40 seconds, washed with water, and then dried with nitrogen to obtain substrate B; S4. Prepare 1 kg of micro-etching agent C by mixing the following raw materials in weight percentage: Polyethyleneimine 25%, nano-graphene oxide 15%, hydroxypropyl β-cyclodextrin-encapsulated tea saponin 20%, triethanolamine 8% and the balance water; The hydroxypropyl β-cyclodextrin-coated tea saponin is prepared by the following method: hydroxypropyl β-cyclodextrin and water are mixed in a mass ratio of 1:3.5 to obtain a wall material solution, and then the wall material solution is spray-dried on the surface of tea saponin to obtain hydroxypropyl β-cyclodextrin-coated tea saponin, wherein the added mass ratio of the wall material solution to the tea saponin is 1:1.1; After diluting the micro-etching agent C and water in a mass ratio of 1:20, the substrate B prepared in step S3 is immersed in the micro-etching agent C prepared for 2 minutes, washed with water and dried with nitrogen to obtain a micro-etching substrate.

[0033] Example 2 A stable and uniform chemical micro-etching method comprises the following steps: S1, cleaning the metal substrate copper plate, and then degreasing it with a degreasing agent to obtain a pretreated substrate; S2. Add the following raw materials in the following mass percentages to mix and prepare 1 kg of micro-etching agent A: Sodium persulfate 35%, sulfuric acid 5%, sodium chloride 10%, ethanol 5% and the balance water; The micro-etching agent A prepared above is diluted by 10 times by mass and then sprayed on the substrate through an HVLP spraying process, and then washed with water to obtain a primary micro-etching substrate; The HVLP spraying process parameters are: spraying distance 20cm, spraying air inlet pressure 1.0 bar, atomization pressure of the hood 0.3 bar, compressed air flow 20cfm, and spraying amount of micro-etching agent A 0.2g / cm 2 ; S3. Prepare 1 kg of micro-etching agent B by mixing the following raw materials in the following mass percentages: 40% acetic acid, 20% of the microcapsule particles containing 8-hydroxyquinoline prepared in Preparation Example 2, 0.5% of 2-hydroxy-N,N,N-trimethylethylamine tetrafluoroborate, 1% of disodium hydrogen phosphate and the balance of water; After diluting the micro-etching agent B with water at a mass ratio of 1:30, the initial micro-etching substrate prepared in step S2 is immersed in the micro-etching agent B prepared by mixing for 30 seconds, washed with water, and then dried with nitrogen to obtain a substrate B; S4. Prepare 1 kg of micro-etching agent C by mixing the following raw materials in weight percentage: Polyethyleneimine 20%, nano-graphene oxide 10%, hydroxypropyl β-cyclodextrin-encapsulated tea saponin 15%, triethanolamine 5% and the balance water; The hydroxypropyl β-cyclodextrin-coated tea saponin is prepared by the following method: hydroxypropyl β-cyclodextrin and water are mixed in a mass ratio of 1:3 to obtain a wall material solution, and then the wall material solution is spray-dried on the surface of tea saponin to obtain hydroxypropyl β-cyclodextrin-coated tea saponin, wherein the added mass ratio of the wall material solution to the tea saponin is 1:1; After diluting the micro-etching agent C and water in a mass ratio of 1:20, the substrate B prepared in step S3 is immersed in the micro-etching agent C prepared for 2 minutes, washed with water and dried with nitrogen to obtain a micro-etching substrate.

[0034] Example 3 A stable and uniform chemical micro-etching method comprises the following steps: S1, cleaning the metal substrate copper plate, and then degreasing it with a degreasing agent to obtain a pretreated substrate; S2. Add the following raw materials in the following mass percentages to mix and prepare 1 kg of micro-etching agent A: Sodium persulfate 45%, sulfuric acid 10%, sodium chloride 15%, ethanol 10% and the balance water; The micro-etching agent A prepared above is diluted by 10 times by mass and then sprayed on the substrate through an HVLP spraying process, and then washed with water to obtain a primary micro-etching substrate; The HVLP spraying process parameters are: spraying distance 25cm, spraying air inlet pressure 2.0 bar, atomization pressure of the hood 0.5 bar, compressed air flow 25cfm, and spraying amount of micro-etching agent A 0.3g / cm 2 ; S3. Prepare 1 kg of micro-etching agent B by mixing the following raw materials in the following mass percentages: 50% hydrofluoric acid, 30% of the microcapsule particles containing 8-hydroxyquinoline prepared in Preparation Example 3, 1.5% of 2-hydroxy-N,N,N-trimethylethylamine tetrafluoroborate, 3% of disodium hydrogen phosphate and the balance of water; After diluting the micro-etching agent B with water at a mass ratio of 1:30, the initial micro-etching substrate prepared in step S2 is immersed in the micro-etching agent B prepared by mixing for 60 seconds, washed with water, and then dried with nitrogen to obtain a substrate B; S4. Prepare 1 kg of micro-etching agent C by mixing the following raw materials in weight percentage: Polyethyleneimine 30%, nano-graphene oxide 20%, hydroxypropyl β-cyclodextrin-encapsulated tea saponin 25%, triethanolamine 10% and the balance water; The hydroxypropyl β-cyclodextrin-coated tea saponin is prepared by the following method: hydroxypropyl β-cyclodextrin and water are mixed in a mass ratio of 1:4 to obtain a wall material solution, and then the wall material solution is spray-dried on the surface of tea saponin to obtain hydroxypropyl β-cyclodextrin-coated tea saponin, wherein the added mass ratio of the wall material solution to the tea saponin is 1:1.2; After diluting the micro-etching agent C and water in a mass ratio of 1:20, the substrate B prepared in step S3 is immersed in the micro-etching agent C prepared for 3 minutes, washed with water and dried with nitrogen to obtain a micro-etching substrate.

[0035] Example 4 A stable and uniform chemical micro-etching method is carried out according to the method in Example 1, except that in step S4, after the substrate B is immersed in the micro-etching agent C and rinsed and dried, it is first heated to 260° C. in a nitrogen atmosphere, kept warm for 25 minutes, then heated to 420° C., kept warm for 50 minutes, and then cooled to room temperature to obtain a micro-etched substrate.

[0036] Example 5 A stable and uniform chemical micro-etching method is carried out according to the method in Example 1, except that in step S4, after the substrate B is immersed in the micro-etching agent C and then rinsed and dried, it is first heated to 250° C. in a nitrogen atmosphere, kept warm for 30 minutes, then heated to 400° C., kept warm for 60 minutes, and then cooled to room temperature to obtain a micro-etched substrate.

[0037] Example 6 A stable and uniform chemical micro-etching method is carried out according to the method in Example 1, except that in step S4, after the substrate B is immersed in the micro-etching agent C and then rinsed and dried, it is first heated to 280° C. in a nitrogen atmosphere, kept warm for 20 minutes, then heated to 450° C., kept warm for 40 minutes, and then cooled to room temperature to obtain a micro-etched substrate.

[0038] Example 7 A stable and uniform chemical micro-etching method is carried out according to the method in Example 1, except that 2-hydroxy-N,N,N-trimethylethylamine tetrafluoroborate is not added to the micro-etching agent B.

[0039] Comparative Example 1 A stable and uniform chemical micro-etching method is carried out according to the method in Example 1, except that the micro-etching agent A in step S2 is also immersed. The specific operation is to mix the prepared micro-etching agent A with water in a mass ratio of 1:10, and then immerse the metal substrate in the micro-etching agent A for 30 seconds.

[0040] Comparative Example 2 A stable and uniform chemical micro-etching method is carried out according to the method in Comparative Example 1, except that the micro-etching agent A is prepared from raw materials including the following mass percentages: Sodium persulfate 40%, sulfuric acid 8%, sodium chloride 8%, 2-hydroxy-N, N, N-trimethylethylamine tetrafluoroborate 1.0%, microcapsule particles containing 8-hydroxyquinoline prepared in Preparation Example 1 10%, hydroxypropyl β-cyclodextrin coated tea saponin 10%, and the balance water.

[0041] Comparative Example 3 A stable and uniform chemical micro-etching method is carried out according to the method in Example 1, except that the microcapsule particles containing 8-hydroxyquinoline in the micro-etching agent B are replaced with 8-hydroxyquinoline in equal amounts.

[0042] Comparative Example 4 A stable and uniform chemical micro-etching method is carried out according to the method in Example 1, except that the hydroxypropyl β-cyclodextrin-coated tea saponin in the micro-etching agent C is replaced with tea saponin in an equal amount.

[0043] Performance Testing Six test base points were selected from different parts of the copper substrate treated by the micro-etching method in the embodiments of the present application and the comparative example, and the roughness of the base points was tested respectively. The test results are shown in Table 1 below.

[0044] Table 1: Referring to the test results in Table 1 above, compared with the test results of the comparative example, the roughness on the substrate after micro-etching by the method in the embodiment of the present application is more uniform, and the micro-etching effect is more uniform and stable. Referring to the test results of Example 1 and Example 4, when Example 4 is subsequently subjected to heat treatment, its erosion effect is more stable. Combined with the test results of Example 7, when 2-hydroxy-N, N, N-trimethylethylamine tetrafluoroborate is not added to the micro-etching solution, its uniformity is reduced. Combined with the test results of Comparative Example 1, when the micro-etching agent A in Comparative Example 1 is directly treated by traditional immersion, it is found that the micro-etching uniformity is significantly reduced. Combined with the test results of Comparative Example 2, when only one micro-etching treatment is performed and it is also an immersion micro-etching treatment, its micro-etching uniformity is significantly reduced. Referring to the test results of Comparative Examples 3 and 4, when 8-hydroxyquinoline or tea saponin is directly added to the micro-etching agent without coating treatment, its uniformity is reduced.

[0045] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A stable and uniform chemical micro-etching method, characterized in that: The following steps are involved: S1, pretreating the metal substrate to obtain a pretreated substrate; S2, spraying the micro-etching agent A containing sodium persulfate onto the substrate by HVLP spraying process, and then washing with water to obtain the initial micro-etching substrate; S3, soaking the initial micro-etching substrate prepared in step S2 in a micro-etching agent B containing dilute acid and microcapsule particles containing 8-hydroxyquinoline, rinsing and drying, to obtain a substrate B; S4, soaking the substrate B prepared in step S3 in a micro-etching agent C containing polyethyleneimine, nano-graphene oxide and hydroxypropyl β-cyclodextrin-coated tea saponin, rinsing and drying, to obtain a micro-etching substrate.

2. A stable and uniform chemical micro-etching method according to claim 1, characterized in that: The microetching agent A in step S2 includes the following raw materials in percentage by mass: Sodium persulfate 35-45%, sulfuric acid 5-10%, sodium chloride 10-15%, ethanol 5-10% and the balance water.

3. A stable and uniform chemical micro-etching method according to claim 1, characterized in that: The micro-etching agent B in step S3 includes the following raw materials in percentage by mass: 40-50% of dilute acid, 20-30% of microcapsule particles containing 8-hydroxyquinoline, 0.5-1.5% of 2-hydroxy-N,N,N-trimethylethylamine tetrafluoroborate, 1-3% of disodium hydrogen phosphate and the balance of water.

4. A stable and uniform chemical micro-etching method according to claim 3, characterized in that: The microcapsule particles containing 8-hydroxyquinoline are prepared by the following method: Dissolve 8-hydroxyquinoline in 3-4 times the mass of ethanol to form a core material solution; Dissolving chitosan in 2-3 times the mass concentration of 30-40% acetic acid solution to form a wall material solution; The prepared core material solution is added to the wall material solution, and then Tween is added, and formaldehyde is added after stirring, and then ammonium bicarbonate is added to adjust the pH to 8, and solidified to form a microcapsule structure, filtered, washed with water, and dried to obtain microcapsule particles; The mass ratio of 8-hydroxyquinoline to chitosan is 1:(0.6-0.8), the amount of Tween added is 3-5% of the weight of the core solution, and the amount of formaldehyde added is 1-3wt% of the amount of chitosan added.

5. A stable and uniform chemical micro-etching method according to claim 1, characterized in that: The dilute acid in step S2 includes one or more of hydrofluoric acid, acetic acid, and citric acid.

6. A stable and uniform chemical micro-etching method according to claim 1, characterized in that: The micro-etching agent C in step S3 includes the following raw materials in weight percentage: Polyethyleneimine 20-30%, nano graphene oxide 10-20%, hydroxypropyl β-cyclodextrin coated tea saponin 15-25%, triethanolamine 5-10% and the balance water.

7. A stable and uniform chemical micro-etching method according to claim 6, characterized in that: Hydroxypropyl β-cyclodextrin encapsulated tea saponin by the following method: Hydroxypropyl β-cyclodextrin and water are mixed in a mass ratio of 1: (3-4) to obtain a wall material solution, and then the wall material solution is spray-dried on the surface of tea saponin to obtain hydroxypropyl β-cyclodextrin-coated tea saponin, wherein the added mass ratio of the wall material solution to tea saponin is 1: (1-1.2).

8. A stable and uniform chemical micro-etching method according to claim 1, characterized in that: During the HVLP spraying process in step S2, the spraying distance is 20-25 cm, the spraying air inlet pressure is 1.0-2.0 bar, the atomization pressure of the air hood is 0.3-0.5 bar, and the compressed air flow rate is 20-25 cfm.

9. A stable and uniform chemical micro-etching method according to claim 1, characterized in that: The specific operation of the metal substrate surface pretreatment in step S1 is: cleaning and degreasing the substrate and then cleaning and drying it to obtain a pretreated substrate.

10. A stable and uniform chemical micro-etching method according to claim 1, characterized in that: In step S4, after the substrate B is immersed in the micro-etching agent C and then rinsed and dried, it is first heated to 250-280° C. in a nitrogen atmosphere, kept warm for 20-30 minutes, then heated to 400-450° C., kept warm for 40-60 minutes, and then cooled to room temperature to obtain a micro-etching substrate.

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