Electroplating solution and electroplating process for circuit board

Abstract

The present application relates to the technical field of electroplating processing of circuit boards, and more specifically, to an electroplating solution and an electroplating process for circuit boards, which are prepared from the following raw materials in parts by weight: 25-40 parts of copper sulfate pentahydrate, 10-20 parts of sulfuric acid, 6-10 parts of boric acid, 3-7 parts of polyvinyl pyrrolidone, 10-20 parts of ammonium sulfate, 2-5 parts of inhibitor, 3-7 parts of brightener, 5-10 parts of complexing agent, 1-5 parts of leveler, and 500 parts of pure water. The electroplating solution prepared by the above formula is environmentally friendly and safe, has high copper plating efficiency, and the copper plating layer obtained by electroplating has a uniform and dense structure, a smooth surface, no voids, seams, etc., and good brightness.

Description

Technical Field

[0001] The present application relates to the technical field of circuit board electroplating processing, and more specifically, to an electroplating solution and an electroplating process for circuit boards. Background Art

[0002] With the rapid development of the electronics industry, PCB circuit boards are widely used in various electronic devices. PCB circuit boards are currently mainly prepared by the electroplating blind hole method. The electroplating blind hole method is to penetrate the conductor patterns on the surface and inner layer of the insulating substrate through the blind hole, and use chemical methods to electroplate a layer of copper inside the blind hole and on the circuit surface, so that the copper layer thickness of the hole wall is increased, the electrical performance of the copper layer is improved, and the connection of the corresponding conductor patterns in different layers is realized.

[0003] When the existing copper electroplating solution is used to electroplate PCB circuit boards, there will be problems such as low hole filling rate, uneven copper deposition, difficult to control plating thickness and low electroplating efficiency, which need to be improved. Summary of the invention

[0004] In order to solve the problems of low hole filling rate, uneven copper deposition, difficult to control plating thickness and low electroplating efficiency when electroplating PCB circuit boards, the present application provides a plating solution and electroplating process for circuit boards.

[0005] In a first aspect, the present application provides an electroplating solution for a circuit board, which adopts the following technical solution:

[0006] An electroplating solution for a circuit board is prepared from the following raw materials in parts by weight:

[0007] 25-40 parts of copper sulfate pentahydrate

[0008] 2-5 parts of sulfuric acid

[0009] Boric acid 6-10 parts

[0010] Polyvinyl pyrrolidone 3-7 parts

[0011] Ammonium sulfate 10-20 parts

[0012] 2-5 parts of inhibitor

[0013] 3-7 parts of brightener

[0014] Complexing agent 5-10 parts

[0015] 1-5 parts of leveling agent

[0016] 500 parts of purified water.

[0017] By adopting the above technical scheme, when the electroplating solution is used for copper plating, the hole filling rate is high, the copper plating efficiency is high, the copper plating is uniform, the copper plating layer and the PBC circuit board have high combination stability, and the copper layer surface obtained is smooth, without depression, without bumps and seamless. The effect of the complexing agent is mainly to form a stable complex with the copper ion, thereby controlling the deposition speed and deposition quality of the copper ion in the electroplating process. The complexing agent can change the activity and distribution of the copper ion in the electroplating solution, so that the copper ion can be more evenly deposited on the circuit board surface, thereby obtaining a more meticulous and more uniform metal coating. In addition, the complexing agent can also play the role of stabilizing the electroplating solution, preventing the copper ion from having adverse reactions such as precipitation or hydrolysis in the electroplating process, thereby ensuring the stability and reliability of the electroplating process.

[0018] When polyvinyl pyrrolidone is dissolved in pure water, it will increase the viscosity of the copper plating solution, adjust the reduction rate of copper ions, and improve the uniformity of copper plating. At the same time, polyvinyl pyrrolidone improves the wettability and adhesion of the plating solution, and makes the bonding between the copper plating layer and the PBC circuit board more firm.

[0019] Sulfuric acid, boric acid and ammonium sulfate increase the conductivity of the electroplating copper solution, prevent the hydrolysis of copper ions, promote the cathode reduction of copper, and help improve the reduction efficiency of copper ions and copper plating efficiency. Inhibitors can inhibit the excessive ionization and precipitation of copper ions during the electroplating process, thereby ensuring the quality and mirror brightness of the copper coating.

[0020] The main function of brightener in the electroplating solution is to improve the appearance and quality of the electroplated layer. Specifically, it can increase the smoothness, brightness and uniformity of the electroplated layer, thereby improving the overall performance and reliability of the circuit board. Brightener is usually an organic compound, such as dihydroxypropyl mercaptan, which can be adsorbed on the surface of the PCB circuit board, change the microstructure of the electroplated layer, and improve the copper plating effect, so that the copper plating layer has better brightness and electrical properties. In addition, brightener can also reduce defects such as bubbles and pinholes in the electroplating process, and improve electroplating efficiency and quality.

[0021] During the electroplating process, due to the uneven distribution of copper ions in the electrolyte and the action of the current, the surface of the electroplating layer will appear uneven. The leveling agent can eliminate the unevenness on the surface of the electroplating layer and make the copper-plated surface smooth and uniform.

[0022] Preferably, the electroplating solution for circuit boards is prepared by the following method:

[0023] According to the mass ratio of the above raw materials, add copper sulfate pentahydrate into a beaker, add 400 parts of pure water until the copper sulfate pentahydrate is completely dissolved, then add a chelating agent, and wait until it is completely dissolved, then add polyvinyl pyrrolidone, boric acid, ammonium sulfate, inhibitor, brightener, sulfuric acid and leveling agent respectively, stir evenly, then add the remaining pure water to prepare an electroplating solution for circuit boards.

[0024] Preferably, it is prepared from the following raw materials in parts by weight:

[0025] 30 parts of copper sulfate pentahydrate

[0026] 3 parts of sulfuric acid

[0027] Boric acid 6-10 parts

[0028] 4 parts of polyvinyl pyrrolidone

[0029] 15 parts of ammonium sulfate

[0030] 3 parts of inhibitor

[0031] 4 parts of brightener

[0032] 8 parts of complexing agent

[0033] 4 parts of leveling agent

[0034] 500 parts of purified water.

[0035] By adopting the above technical scheme, the dosage of the raw materials of the electroplating solution for the circuit board is optimized, and the copper plating effect of the copper plating solution is further improved. The obtained copper plating layer has no seams, no convex points, low impurities, good even plating property, dense structure, small surface roughness, no voids, good brightness, low concavity and strong bonding ability with the PCB circuit board.

[0036] Preferably, the molecular weight of the polyvinyl pyrrolidone is 500-2000.

[0037] By adopting the above technical solution, the molecular weight of polyvinyl pyrrolidone is optimized, the viscosity of the electroplating solution is adjusted, and then the copper ion reduction speed is adjusted to prevent the copper ion reduction from being too fast or too slow, thereby improving the uniformity of copper plating. At the same time, polyvinyl pyrrolidone improves the wettability and adhesion of the electroplating solution, thereby improving the firmness of the bonding between the copper plating layer and the circuit board.

[0038] Preferably, the leveler comprises a quaternary ammonium salt and / or a pyridine compound.

[0039] By adopting the above technical solution, the dosage and type of the leveling agent are optimized, and the surface flatness and smoothness of the copper-plated layer are improved.

[0040] The copper electrodeposition method is to fill the blind hole from the bottom up to ensure that there is no gap filling. This means that during the electroplating process, the bottom of the hole has the highest copper deposition rate. The uneven local current density distribution will result in less copper deposition at the bottom of the hole during the electroplating process, while more copper is deposited at the hole mouth, gradually closing the hole mouth, and a hole or gap will appear in the middle of the hole. Among them, the quaternary ammonium salt has a positive charge, which has a very strong adsorption and inhibition effect in the high current area, and can inhibit the growth at the hole mouth, thereby reducing the surface copper thickness and improving the uniformity of copper plating; pyridine compounds can inhibit the deposition of the hole mouth and affect the deposition of copper in the hole to a lesser extent, thereby achieving the purpose of uniform blind hole electroplating.

[0041] Preferably, the weight ratio of the quaternary ammonium salt to the pyridine compound is (4-6):3.

[0042] By adopting the above technical solution and optimizing the dosage of quaternary ammonium salt and pyridine compound, the copper plating efficiency is further improved, so that the structure of the copper plating layer is compact and uniform, the surface is smooth, and there are no voids, bumps or joints.

[0043] Preferably, the brightener is obtained by mixing dihydroxypropyl mercaptan, cinnamaldehyde and glutaraldehyde in a weight ratio of 1:(3-6):(4-8).

[0044] By adopting the above technical solution, the type and amount of brightener are optimized, and the surface gloss of the coating can be effectively improved. Among them, dihydroxypropyl mercaptan is an organic compound containing hydroxyl and thiol functional groups. These functional groups can react chemically with the polished PCB circuit board, thereby changing the microstructure and optical properties of the PCB circuit board to ensure the copper plating effect. Cinnamaldehyde is an organic compound with an aldehyde group and a benzene ring structure, which makes it have good reactivity and stability. In the application of a brightener, cinnamaldehyde can react chemically with the copper-plated surface to form a dense protective film, thereby increasing the gloss of the copper-plated surface and preventing oxidation. Glutaraldehyde is also an organic compound with two aldehyde groups, which makes it more reactive. Glutaraldehyde can react with oxides or hydroxides on the copper surface, can fill the tiny pits and gaps on the surface of the copper-plated layer, make the surface of the copper-plated layer smoother, thereby increasing the gloss. By reasonably adjusting the amount of dihydroxypropyl mercaptan, cinnamaldehyde and glutaraldehyde, the brightness and smoothness of the copper-plated layer can be further improved.

[0045] Preferably, the complexing agent includes at least one of ethylene thiourea, tetramethyl thiourea, thiosemicarbazide and thiourea.

[0046] By adopting the above technical scheme, the complex stability between copper ions and the complexing agent is improved, so that the speed of releasing copper ions is moderate. If the release speed of copper ions is too fast, the thickness of the copper plating layer will be uneven and the deep plating ability of the copper plating solution will be reduced; if the release speed of copper ions is too slow, the formation of the copper layer will be affected, the copper plating layer will be thin, and poor smoothness will be avoided.

[0047] Preferably, the inhibitor is potassium ferrocyanide.

[0048] By adopting the above technical solution, the excessive ionization and precipitation of copper ions during the electroplating process can be further suppressed, thereby ensuring the quality and mirror brightness of the copper plating layer.

[0049] In a second aspect, the present application provides an electroplating process, which adopts the following technical solution:

[0050] An electroplating process comprises the following steps:

[0051] Placing the PCB board with the blind hole in an electroplating tank filled with an electroplating copper solution and electroplating under air stirring to obtain a copper-plated layer; the electroplating copper solution is the electroplating solution for the circuit board described in the first aspect;

[0052] The current density of the electroplating is 1-4A / dm 2 , electroplating temperature is 20-30℃, and electroplating time is 20-40min.

[0053] By adopting the above technical scheme, the copper plating layer has a tight structure, no voids and depressions, low impurities in the plating layer, good even plating property, dense structure, small surface roughness, no voids, no bumps, good brightness and strong bonding ability with the PCB circuit board.

[0054] In summary, this application has the following beneficial effects:

[0055] 1. In the present application, a copper electroplating solution is prepared by using copper sulfate pentahydrate, sulfuric acid, boric acid, polyvinyl pyrrolidone, ammonium sulfate, an inhibitor, a brightener, a complexing agent, a leveling agent and pure water. When the electroplating solution is used for copper plating, the copper ion reduction rate can be well controlled, the copper plating effect can be improved, and the uniformity, brightness, smoothness and stability of the copper layer can be further improved, ensuring that the copper layer has no depressions, no bumps and no seams. DETAILED DESCRIPTION

[0056] Example

[0057] Example 1

[0058] A plating solution for a circuit board is prepared by the following method:

[0059] Add 250g of copper sulfate pentahydrate into a beaker, add 4000g of pure water until the copper sulfate pentahydrate is completely dissolved, then add 50g of chelating agent (tartaric acid), and wait until it is completely dissolved. Then add 30g of polyvinyl pyrrolidone, 60g of boric acid, 100g of ammonium sulfate, 20g of inhibitor (polyethylene glycol), 30g of brightener (dihydroxypropyl mercaptan), 20g of sulfuric acid (mass fraction is 98%) and 10g of leveling agent (dimethyldiallylammonium chloride), stir evenly, and then add the remaining 1000g of pure water to prepare a plating solution for circuit boards.

[0060] The molecular weight of polyethylene glycol is 1000, and the molecular weight of polyvinyl pyrrolidone is 500.

[0061] The difference between Example 2-4 and Example 1 is that the types and amounts of some raw materials used to prepare the electroplating solution for circuit boards are different. The specific differences are shown in Table 1:

[0062] Table 1 Types and amounts of raw materials used in the electroplating solution for circuit boards in Examples 1-4

[0063]

[0064] The weight average molecular weight of the butanol-ethylene oxide-propylene oxide copolymer was 5,000.

[0065] Example 5

[0066] A plating solution for a circuit board. The difference between this embodiment and embodiment 1 is that the leveling agent is 2,2-dithiodipyridine, and the types, amounts and parameters of other raw materials are consistent with those in embodiment 1.

[0067] Example 6

[0068] A plating solution for a circuit board, the difference between this embodiment and embodiment 1 is that the leveling agent is 2,2-dithiodipyridine, and the types, amounts and parameters of other raw materials are consistent with those of embodiment 1

[0069] Example 7

[0070] A plating solution for circuit boards. The difference between this embodiment and embodiment 1 is that the leveling agent includes 5.7 g of dimethyldiallylammonium chloride and 4.3 g of 2,2-dithiodipyridine, and the types, amounts and parameters of other raw materials are consistent with those in embodiment 1.

[0071] Example 8

[0072] A plating solution for circuit boards. The difference between this embodiment and embodiment 5 is that the leveling agent includes 6.7 g of dimethyldiallylammonium chloride and 3.3 g of 2,2-dithiodipyridine, and the types, amounts and parameters of other raw materials are consistent with those in embodiment 5.

[0073] Example 9

[0074] A plating solution for circuit boards. The difference between this embodiment and embodiment 1 is that a brightener is obtained by mixing 3.75 g of dihydroxypropyl mercaptan, 11.25 g of cinnamaldehyde and 15 g of glutaraldehyde in a weight ratio of 1:3:4, and the types, amounts and parameters of other raw materials are consistent with those in embodiment 1.

[0075] Example 10

[0076] A plating solution for circuit boards. The difference between this embodiment and embodiment 8 is that a brightener is obtained by mixing 2 g of dihydroxypropyl mercaptan, 12 g of cinnamaldehyde and 16 g of glutaraldehyde in a weight ratio of 1:6:8, and the types, amounts and parameters of other raw materials are consistent with those in embodiment 8.

[0077] Embodiment 11

[0078] A plating solution for circuit boards. The difference between this embodiment and embodiment 10 is that nicotinic acid is used instead of dihydroxypropyl mercaptan, and the types, amounts and parameters of other raw materials are consistent with those of embodiment 10.

[0079] Example 12

[0080] A plating solution for circuit boards. The difference between this embodiment and embodiment 10 is that indoleacetic acid is used instead of cinnamaldehyde, and the types, amounts and parameters of other raw materials are consistent with those of embodiment 10.

[0081] Example 13

[0082] A plating solution for circuit boards. The difference between this embodiment and embodiment 10 is that indoleacetic acid is used instead of glutaraldehyde, and the other raw material types, amounts and parameters are consistent with those of embodiment 10.

[0083] Embodiment 14

[0084] A plating solution for circuit boards. The difference between this embodiment and embodiment 1 is that the complexing agent is ethylene thiourea, and the types, amounts and parameters of other raw materials are consistent with those in embodiment 1.

[0085] Embodiment 15

[0086] A plating solution for circuit boards. The difference between this embodiment and embodiment 10 is that the complexing agent is ethylene thiourea, and the types, amounts and parameters of other raw materials are consistent with those of embodiment 10.

[0087] Example 16

[0088] A plating solution for circuit boards. The difference between this embodiment and embodiment 1 is that the inhibitor is potassium ferrocyanide, and the types, amounts and parameters of other raw materials are consistent with those in embodiment 1.

[0089] Embodiment 17

[0090] A plating solution for circuit boards. The difference between this embodiment and embodiment 15 is that the inhibitor is potassium ferrocyanide, and the types, amounts and parameters of other raw materials are consistent with those of embodiment 15.

[0091] Comparative Example

[0092] Comparative Example 1

[0093] A plating solution for circuit boards. The difference between this comparative example and Example 1 is that polypropylene glycol is used instead of polyvinyl pyrrolidone, and the types, amounts and parameters of other raw materials are consistent with those in Example 1.

[0094] The molecular weight of polypropylene glycol is 2000.

[0095] Comparative Example 2

[0096] A plating solution for circuit boards. The difference between this comparative example and Example 1 is that no boric acid is added, and the types, amounts and parameters of other raw materials are consistent with those in Example 1.

[0097] Comparative Example 3

[0098] A plating solution for circuit boards. The difference between this comparative example and Example 1 is that ferric chloride is used instead of ammonium sulfate, and the types, amounts and parameters of other raw materials are consistent with those in Example 1.

[0099] Application Examples

[0100] Application Example 1

[0101] An electroplating process comprises the following steps:

[0102] Place the PCB with blind holes in the electroplating tank filled with copper plating solution, install the anode, connect the positive power wire to the two anodes, turn on the aeration and stirring, and complete the chemical plating of the PCB with blind holes on the Atotech horizontal copper wire (scratch the mark on the board): Place it in the Haring tank, connect the cathode wire, turn on the power, and the electroplating current density is 1A / dm 2 , the electroplating temperature is 20°C, the electroplating time is 20 minutes, after plating, washing, anti-oxidation, washing, drying, and obtaining a copper-plated layer;

[0103] The copper electroplating solution is the electroplating solution for circuit boards prepared in Example 1;

[0104] The size of the PCB board with blind holes is 5cm*15cm, the board thickness is 0.45mm, the blind hole diameter is 80μm, the hole depth is 100μm (including the bottom copper thickness of 5μm); the aspect ratio is 2.25:1.

[0105] The difference between Application Example 2-24 and Application Example 1 is that the sources of the electroplating solution used for the circuit board are different. The specific differences are shown in Table 2:

[0106] Table 2 Sources of plating solutions for circuit boards

[0107] Application Examples source Application Example 1 Example 1 Application Example 2 Example 2 Application Example 3 Example 3 Application Example 4 Example 4 Application Example 5 Example 5 Application Example 6 Example 6 Application Example 7 Example 7 Application Example 8 Example 8 Application Example 9 Example 9 Application Example 10 Example 10 Application Example 11 Embodiment 11 Application Example 12 Example 12 Application Example 13 Example 13 Application Example 14 Embodiment 14 Application Example 15 Embodiment 15 Application Example 16 Example 16 Application Example 17 Embodiment 17 Application Example 18 Comparative Example 1 Application Example 19 Comparative Example 2 Application Example 20 Comparative Example 3

[0108] Performance testing

[0109] The samples prepared in accordance with Example 1-20 were subjected to appearance inspection and copper plating layer inspection.

[0110] Inspection method / test method Appearance inspection: Observe the brightness, uniformity and cracks of the copper layer in application examples 1-20. The copper layer is flat and smooth without bumps, pits and cracks, which is a qualified product; the copper layer with copper nodules, bumps, cracks and bubbles is a defective product, and the number of defective products in each application example is counted. Note: Prepare 50 samples for each application example, and record the number of defective products in each application example.

[0111] Copper plating layer detection: The samples prepared in each application example were sliced ​​at the blind hole, and the surface copper thickness and hole copper thickness were tested with a metallographic microscope, where surface copper thickness = copper plating layer thickness (excluding bottom copper thickness); concavity = dielectric layer + surface copper thickness - hole copper thickness; filling rate = hole copper thickness / (dielectric layer + surface copper thickness) × 100%. Randomly select 5 samples and take the average value. The experimental data is shown in Table 3:

[0112] Table 3 Experimental data of application examples 1-20

[0113]

[0114]

[0115] It can be seen from Application Examples 1-20 and Table 3 that the electroplating solution for circuit boards prepared by the present application is used for copper plating to obtain a copper plating layer with a uniform and dense structure, good brightness, smooth surface, no voids, and no seams.

[0116] Comparing Example 1 with Comparative Examples 1-3, the number of unqualified samples in Comparative Examples 1, 2, and 3 are 6, 7, and 8, respectively. The thickness of the copper plating layer of Comparative Examples 1-3 is thinner than that of Example 1, the depression of Comparative Examples 1-3 is greater than that of Example 1, and the filling rate of Comparative Examples 1-3 is less than that of Example 1, indicating that by using sulfuric acid, polyvinyl pyrrolidone, ammonium sulfate and other raw materials together, the depression at the blind hole of the circuit board can be reduced, the filling rate of the blind hole of the circuit board can be improved, and the copper plating layer can be dense and uniform.

[0117] From the experimental results of Example 4, the thickness of the copper plating layer in Example 4 is relatively thick, and there are fewer defective products, which shows that the dosage ratio within this range can improve the copper plating efficiency and reduce the number of defective products.

[0118] Compared with Example 1 and Example 5-8, there are no defective products in Example 7-8, the copper layer thickness is thick, the depression degree is reduced, and the hole filling rate is increased, indicating that the use of quaternary ammonium salt and pyridine compound together is beneficial to improving the copper plating efficiency and the dense and uniform copper plating layer, and reducing the number of defective products.

[0119] By comparing Example 1 with Example 9, and Example 10 with Examples 11-13, Example 10 has the least defective products, the thickest copper layer, the lowest depression, and the highest hole filling rate, indicating that the use of dihydroxypropyl mercaptan, cinnamaldehyde, and glutaraldehyde together is beneficial to improving the copper plating efficiency and making the copper plating layer dense and uniform, and reducing the number of defective products.

[0120] Comparing Example 1 with Example 14, Example 14 has the least number of defective products, the thickest copper layer, the lowest degree of concavity, and the highest hole filling rate, indicating that optimizing the type of complexing agent is beneficial to improving the copper plating efficiency and making the copper plating layer dense and uniform, and reducing the number of defective products.

[0121] Comparing Example 1 with Example 16, Example 16 has the least number of defective products, the thickest copper layer, the lowest degree of concavity, and the highest hole filling rate, indicating that over-optimizing the type of inhibitor is beneficial to improving the copper plating efficiency and the dense and uniform copper plating layer, and reducing the number of defective products.

[0122] 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 plating solution for a circuit board, characterized in that: Prepared from the following raw materials in parts by weight: 25-40 parts of copper sulfate pentahydrate 2-5 parts of sulfuric acid 6-10 parts of boric acid Polyvinyl pyrrolidone 3-7 parts Ammonium sulfate 10-20 parts 2-5 parts of inhibitor 3-7 parts of brightener Complexing agent 5-10 parts 1-5 parts of leveling agent 500 parts of purified water; The leveling agent includes a quaternary ammonium salt and / or a pyridine compound; The weight ratio of the quaternary ammonium salt to the pyridine compound is (4-6):3; The brightener is obtained by mixing dihydroxypropyl mercaptan, cinnamaldehyde and glutaraldehyde in a weight ratio of 1: (3-6): (4-8); The leveling agent is dimethyldiallylammonium chloride, 2,2-disulfide dipyridine, methacryloyloxyethyl dimethylammonium chloride or dimethyldiallylammonium chloride.

2. The electroplating solution for circuit boards according to claim 1, characterized in that: Prepared from the following raw materials in parts by weight: 30 parts of copper sulfate pentahydrate 3 parts of sulfuric acid 6 parts of boric acid 4 parts of polyvinyl pyrrolidone 15 parts of ammonium sulfate 3 parts of inhibitor 4 parts of brightener 8 parts of complexing agent Dispersant 4 parts 500 parts of purified water.

3. The electroplating solution for circuit boards according to claim 1 or 2, characterized in that: The molecular weight of the polyvinyl pyrrolidone is 500-2000.

4. The electroplating solution for circuit boards according to claim 1, characterized in that: The complexing agent includes at least one of ethylene thiourea, tetramethyl thiourea, thiosemicarbazide and thiourea.

5. The electroplating solution for circuit boards according to claim 1, characterized in that: The inhibitor is potassium ferrocyanide.

6. An electroplating process, characterized in that: The method comprises the following preparation steps: The PCB board with the blind hole is placed in a plating tank filled with a copper plating solution and electroplated under air stirring to obtain a copper-plated layer; the copper plating solution is the plating solution for circuit boards according to any one of claims 1 to 5, The current density of the electroplating is 1-4A / dm 2 , electroplating temperature is 20-30℃, and electroplating time is 20-40min.

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