Acid copper plating polishing agent and preparation method thereof

Abstract

The invention relates to the technical field of electroplating, in particular to an acidic copper plating polishing agent and a preparation method thereof. The acidic copper plating brightening agent is prepared from the following raw materials in parts by mass: 25 to 30 parts of brightening agent, 6 to 8 parts of leveling agent, 40 to 50 parts of wetting agent, 7 to 10 parts of hydroxyethyl cellulose, 8 to 12 parts of collagen and 900 to 930 parts of deionized water. The acidic copper plating polishing agent has excellent technical effects, can be widely applied to the field of copper electroplating, improves the quality of a copper electroplating layer, including glossiness, tensile strength, elongation, hole filling efficiency, uniform plating capacity, through hole deep plating capacity and the like, and meets the requirements of circuit board plated through hole conduction capacity.

Description

Technical Field

[0001] The present application relates to the technical field of electroplating, and in particular to an acid copper plating brightener and a preparation method thereof. Background Art

[0002] In the ever-changing information age, electronic products are developing in the direction of miniaturization and diversification of functions, and the wiring density of printed circuit boards (PCBs) is constantly increasing. In the manufacturing process of PCBs, high-density interconnection (HDI), build-up and blind vias can effectively improve the wiring density of PCBs. For HDI boards with blind vias, customers often require electroplated copper to be filled in the blind vias, that is, copper filling is used to ensure the reliability of interlayer interconnection. Therefore, the performance of electroplated copper additives faces huge challenges.

[0003] The current circuit board hole metallization process requires that the metal layer and the substrate must have sufficient bonding strength to ensure good circuit interconnection performance and withstand the thermal shock and mechanical stress that may be encountered during manufacturing and use. The existing acid copper plating brightener is bound to be unable to meet the needs of high-performance circuit board manufacturing. Summary of the invention

[0004] The purpose of the present application is to provide an acid copper plating brightener and a preparation method thereof in view of the deficiencies in the current technology. The electroplated copper layer obtained by using the acid copper plating brightener prepared by the present application has excellent gloss, tensile strength and elongation, as well as high hole filling efficiency, and excellent all-plating ability and through-hole deep plating ability, meeting the requirements for through-hole conductivity of circuit board plating.

[0005] In a first aspect, the present application provides an acid copper plating brightener, which adopts the following technical solution: An acid copper plating brightener comprises the following raw materials by weight: 25-30 parts of brightener, 6-8 parts of leveler, 40-50 parts of wetting agent, 7-10 parts of hydroxyethyl cellulose, 8-12 parts of collagen and 900-930 parts of deionized water.

[0006] By adopting the above technical scheme, the acid copper plating brightener of the present application includes the following components: brightener, leveler, wetting agent, hydroxyethyl cellulose, collagen and deionized water. These components work synergistically, so that the electroplated copper layer has excellent gloss, tensile strength and elongation, as well as high hole filling efficiency and excellent all-plating ability and through-hole deep plating ability. Brightener: Control the nucleation and growth of the copper layer in copper electrodeposition, improve the gloss by refining the grains, and make the coating surface smoother and denser. Leveler (pyridinium benzyl ammonium chloride): used in the copper electroplating process, nitrogen-containing aromatic heterocycles are more likely to undergo electrophilic reactions, making the compound easy to adsorb on the cathode surface, improving the hole filling efficiency and excellent all-plating ability and through-hole deep plating ability. Wetting agent: Different wetting agents have different inhibition abilities on the copper plate surface. By compounding a variety of synergistic wetting agents, the copper plating grains are refined more uniformly, and uniform, dense and fine grains are obtained. Hydroxyethyl cellulose and collagen: synergistically improve the glossiness, tensile strength and elongation of the electroplated copper layer. In summary, the acidic copper plating brightener of the present application can obtain an electroplated copper layer with excellent performance through the synergistic effect of each component, meeting the requirements for the conductivity of the through-holes of the circuit board.

[0007] Preferably, the mass ratio of the hydroxyethyl cellulose to the collagen is 1:1.

[0008] By adopting the above technical scheme, hydroxyethyl cellulose is a water-soluble polymer with good film-forming property and stability. In the electroplating process, it can be used as an additive to help form a uniform and smooth coating. At the same time, it can also be used as a wetting agent to reduce surface tension and improve the wettability of the plating solution, thereby improving the adhesion and covering ability of the coating. Collagen is a natural high molecular protein with good biocompatibility and bioactivity. In the electroplating process, it can be used as a brightener and leveling agent to improve the gloss and flatness of the coating. In addition, collagen also has excellent tensile strength and elongation, which can improve the mechanical properties of the coating. The synergistic effect between hydroxyethyl cellulose and collagen is mainly reflected in the following aspects: Complementarity: Hydroxyethyl cellulose mainly provides film-forming property and stability, while collagen mainly provides brightness and leveling property. The combination of the two can give full play to their respective advantages and achieve better electroplating effect. Interaction: Hydroxyethyl cellulose and collagen may interact in the solution to form a complex. This complex may have better properties, such as higher stability, stronger adhesion, etc., thereby further improving the quality of the coating. Synergistic effect: Hydroxyethyl cellulose and collagen may have a synergistic effect during the electroplating process and jointly affect the copper electrodeposition process. For example, they may jointly regulate the nucleation and growth process of the copper layer, refine the grains, and improve the gloss; or jointly improve the wettability of the plating solution, improve the hole filling efficiency and the ability to plate evenly. In short, the synergistic effect of hydroxyethyl cellulose and collagen in the acid copper plating brightener helps to improve the quality of the electroplated copper layer, achieve excellent gloss, tensile strength and elongation, as well as efficient hole filling ability and through-hole deep plating ability.

[0009] Preferably, the brightener is composed of sodium polydisulfide propane sulfonate, sodium thiazoline disulfide propane sulfonate and methylene blue in a mass ratio of 5:3:2.

[0010] By adopting the above technical scheme, the role of the brightener is to control the nucleation and growth of the copper layer in copper electrodeposition, refine the grains in the instantaneous nucleation process controlled by three-dimensional diffusion, improve the glossiness, and make the coating surface smoother and denser. Sodium polydisulfide propane sulfonate (SPS) is a commonly used brightener, which can be adsorbed on the active sites on the copper surface, inhibit the deposition rate of copper, thereby refining the copper grains and improving the brightness and flatness of the coating. Sodium thiazolyl disulfide propane sulfonate (MPS) is a leveling agent, which can form a complex with SPS and co-adsorb on the active sites on the copper surface, further inhibit the deposition rate of copper, make the copper grains finer, and improve the brightness and flatness of the coating. Methylene blue (MB) is a dye, which can form a ternary complex with SPS and MPS, co-adsorb on the active sites on the copper surface, further inhibit the deposition rate of copper, make the copper grains finer, and improve the brightness and flatness of the coating. At the same time, MB also has a certain antioxidant effect, which can protect the copper coating from oxidation. Through the synergistic effect of these three substances, the copper electrodeposition process can be effectively controlled to obtain an electroplated copper layer with excellent gloss, tensile strength and elongation, which meets the conductivity requirements of the through-holes of the circuit board.

[0011] Preferably, the preparation method of the polysodium disulfide propane sulfonate comprises the following steps: S41, add 6L methanol and 1824g thiourea to an enamel kettle and stir evenly, cool to 20°C, slowly drop 2440g 1,3-propane sultone, control the dropwise addition temperature at 25-30°C, after the dropwise addition is completed, continue to react at 32°C for 4-5 hours, centrifuge, and dry to obtain 3-isothiourea propane sulfonic acid; S42, add 1980g3-isothiourea propane sulfonic acid to 8.3L 26% ammonia solution in an enamel kettle, heat to 60°C with stirring, stir until the salt is dissolved, cool to 13-15°C and keep for 1 hour, evaporate on a rotary evaporator until solid precipitates, cool to 13-15°C, and recrystallize with a mixed solvent of chloroform and isopropanol in a mass ratio of 1:1.3 to obtain 3-mercaptopropane ammonium sulfonate; S43, dissolve 1590g3-mercaptopropane ammonium sulfonate with 4L distilled water, pass through an ion exchange resin, the effluent is an aqueous solution of 3-mercaptopropane sulfonic acid, rinse the column with 6L distilled water until the eluate is neutral, and obtain an aqueous solution of 3-mercaptopropane sulfonic acid; S44, add 564g 30% hydrogen peroxide to the 3-mercaptopropanesulfonic acid aqueous solution, keep at 13-15°C for 8-10 hours, neutralize with 400g NaOH aqueous solution, evaporate the neutralized solution to dryness with a rotary evaporator to obtain high-purity sodium polydisulfide dipropane sulfonate.

[0012] By adopting the above technical solution, high-purity sodium polydisulfide propane sulfonate is prepared, which can control the nucleation and growth of the copper layer in copper electrodeposition, refine the grains, and thus improve the glossiness of the copper-plated layer. The synergistic effect of sodium polydisulfide propane sulfonate with hydroxyethyl cellulose and collagen can improve the tensile strength and elongation of the electroplated copper layer. The synergistic effect of sodium polydisulfide propane sulfonate and other wetting agents can make the copper-plated grains more uniformly refined, and obtain uniformly sized, dense and fine grains, thereby improving the hole filling efficiency and the ability to evenly plate. Sodium polydisulfide propane sulfonate can also obtain super filling without voids and gaps in blind holes with higher aspect ratios, and has a good deep plating ability, which meets the requirements of the through-hole conductivity of the circuit board.

[0013] Preferably, the leveling agent is benzyl pyridinium chloride.

[0014] Preferably, the preparation method of the pyridinium benzyl ammonium chloride is to add pyridine into a reactor, heat to 50-60°C, stir at 300rpm for 1-2h, and add benzyl chloride dropwise using a constant pressure dropping funnel, heat to 50-60°C, reflux for 3-4h, transfer the product into a round beaker, cool to obtain a slightly light brown viscous liquid; recrystallize with petroleum ether, filter, and obtain pyridinium benzyl ammonium chloride.

[0015] By adopting the above technical scheme, the prepared pyridine benzyl ammonium chloride has high purity and good leveling performance, and is suitable for use as a leveling agent in the copper electroplating process. Pyridine benzyl ammonium chloride helps to improve the hole filling efficiency of the electroplating process by promoting the uniform distribution of copper ions on the cathode surface. Pyridine benzyl ammonium chloride can make the grain refinement of the electroplated copper layer more uniform, thereby obtaining uniform, dense and fine grains, which helps to enhance the uniformity of the overall coating. During the electroplating process, pyridine benzyl ammonium chloride helps copper ions to deposit deeper into the through-holes, thereby improving the deep plating ability and ensuring that good conduction ability can be maintained even in complex circuit board plated through-holes. The nitrogen-containing aromatic heterocycle in pyridine benzyl ammonium chloride is prone to electrophilic reaction, which makes the compound more easily adsorbed on the cathode surface, thereby providing a more stable electroplating environment during the electroplating process. Pyridine benzyl ammonium chloride works synergistically with other ingredients (such as wetting agents, brighteners, etc.) to jointly improve the performance of the electroplated copper layer. For example, by working synergistically with brighteners, it can further refine the grains and enhance the glossiness; by working synergistically with wetting agents, it can improve the smoothness and density of the coating.

[0016] Preferably, the usage ratio of pyridine, benzyl chloride and petroleum ether is 1 mol:1 mol:550-600 mL.

[0017] Preferably, the wetting agent is at least one of sodium lauryl sulfate, fatty amine polyoxyethylene ether and polyethylene oxide polypropylene oxide monobutyl ether.

[0018] Preferably, the wetting agent is composed of sodium lauryl sulfate, fatty amine polyoxyethylene ether and polyethylene oxide polypropylene oxide monobutyl ether in a mass ratio of 5:8:2.

[0019] By adopting the above technical scheme, in the acid copper plating brightener, the wetting agent is composed of sodium dodecyl sulfate, fatty amine polyoxyethylene ether and polyethylene oxide polypropylene oxide monobutyl ether in a mass ratio of 5:8:2. These three wetting agents each have their own unique functions and play a synergistic role in the electroplating process. Sodium dodecyl sulfate: This is an anionic surfactant that can reduce the surface tension of the electroplating solution and improve the wettability of the solution to the substrate. It helps the electroplating solution to spread better on the surface of the plated object, ensuring that the copper ions are evenly deposited on the substrate, thereby obtaining a smooth and uniform coating. Fatty amine polyoxyethylene ether: This non-ionic surfactant has excellent wetting and penetration capabilities and can improve the copper deposition in high current density areas. It stabilizes the copper ions in the electroplating solution, reduces the local excessive deposition of copper ions, and avoids the formation of a rough coating. Polyethylene oxide polypropylene oxide monobutyl ether: As a copolymer non-ionic surfactant, it helps to improve the uniformity and brightness of the coating. The wetting agent can form a uniform adsorption film on the electrode surface, which helps to control the crystallization process of copper, making the grains finer and the coating smoother and finer. The synergistic effect of these three wetting agents is manifested in: working together to reduce surface tension, improving the solution's ability to cover the substrate, and ensuring that copper ions are evenly distributed across the entire workpiece surface. Stabilizing the plating solution to prevent copper ions from depositing too quickly in specific areas, thereby avoiding uneven coating and scorching. Controlling the crystallization process, promoting the formation of small and uniform grains, and improving the gloss and smoothness of the coating.

[0020] In summary, through the reasonable ratio and interaction of these wetting agents, the performance of acid copper plating brightener can be significantly improved, and a high-quality copper plating layer can be obtained to meet the requirements of precision circuit board manufacturing.

[0021] In a second aspect, the present application provides a method for preparing an acid copper plating brightener, using the following technical solution: As a general technical concept, the present application also provides a method for preparing the above-mentioned acid copper plating brightener, comprising the following steps: adding brightener, leveling agent, wetting agent, hydroxyethyl cellulose and collagen in sequence according to mass fractions to deionized water and mixing them thoroughly, heating to a temperature of 80-90°C, maintaining a stirring rate of 150-180r / min and stirring the reaction time for 1-2h to obtain an acid copper plating brightener.

[0022] In summary, the beneficial technical effects of this application are: 1. Excellent gloss, tensile strength and elongation: The synergistic effect of hydroxyethyl cellulose and collagen helps to improve the gloss, tensile strength and elongation of the electroplated copper layer. Brightener controls the nucleation and growth of the copper layer in copper electrodeposition, refines the grains, further improves the gloss, and makes the coating surface smoother and denser.

[0023] 2. Efficient hole filling and all-plating ability: By compounding a variety of synergistic wetting agents, the copper plating grains are refined more evenly, and uniform, dense and fine grains are obtained. The use of pyridine benzyl ammonium chloride as a leveling agent in the copper electroplating process improves the hole filling efficiency and all-plating ability.

[0024] 3. Excellent through-hole deep plating capability: The acid copper plating brightener of the present application can also obtain super filling without voids and gaps in blind holes with higher aspect ratios, meeting the requirements of through-hole conductivity of circuit boards.

[0025] 4. Improve the overall quality of the electroplated copper layer: By optimizing the raw material ratio and preparation process, the acid copper plating brightener of the present application can effectively improve the overall quality of the electroplated copper layer, including gloss, tensile strength, elongation, hole filling efficiency, even plating ability and through-hole deep plating ability. DETAILED DESCRIPTION

[0026] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0027] Preparation Example 1 Preparation of Sodium Polydisulfide Dipropane Sulfonate The preparation method of poly sodium disulfide propane sulfonate comprises the following steps: S41, add 6L methanol and 1824g thiourea to an enamel kettle and stir evenly, cool to 20°C, slowly drop 2440g 1,3-propane sultone, control the dropwise addition temperature at 28°C, after the dropwise addition is completed, continue to react at 32°C for 4.5 hours, centrifuge, and dry to obtain 3-isothiourea propane sulfonic acid; S42, add 1980g3-isothiourea propanesulfonic acid to 8.3L26% ammonia solution in an enamel kettle, heat to 60°C with stirring, stir until the salt is dissolved, cool to 14°C and keep for 1 hour, evaporate on a rotary evaporator until solid precipitates, cool to 14°C, and recrystallize with a mixed solvent of chloroform and isopropanol in a mass ratio of 1:1.3 to obtain 3-mercaptopropanesulfonic acid ammonium; S43, dissolving 1590g of 3-mercaptopropane ammonium sulfonate with 4L of distilled water, passing through an ion exchange resin, and the effluent is an aqueous solution of 3-mercaptopropane sulfonic acid. The column is washed with 6L of distilled water until the eluate is neutral, to obtain an aqueous solution of 3-mercaptopropane sulfonic acid; S44, add 564g 30% hydrogen peroxide to the 3-mercaptopropanesulfonic acid aqueous solution, keep at 14°C for 9 hours, neutralize with 400g NaOH aqueous solution, evaporate the neutralized solution to dryness with a rotary evaporator to obtain high-purity sodium polydisulfide dipropane sulfonate.

[0028] Preparation Example 2 Preparation of pyridinium benzyl ammonium chloride The preparation method of the pyridinium benzyl ammonium chloride comprises the following steps: adding 1 mol of pyridine into a reactor, heating to 550° C., stirring at 300 rpm for 1.5 h, and dripping 1 mol of benzyl chloride using a constant pressure dropping funnel, heating to 55° C., and reflux reaction for 3.6 h, transferring the product into a round beaker, and cooling to obtain a slightly light brown viscous liquid; and recrystallizing with 580 mL of petroleum ether, filtering, and obtaining the pyridinium benzyl ammonium chloride.

[0029] Example 1 An acid copper plating brightener comprises the following raw materials, measured by weight: 25 g of brightener, 6 g of pyridinium benzyl ammonium chloride, 40 g of wetting agent, 7 g of hydroxyethyl cellulose, 8 g of collagen, and 900 g of deionized water. The brightener is composed of sodium polydisulfide propane sulfonate, sodium thiazoline disulfide propane sulfonate, and methylene blue in a weight ratio of 5:3:2, and the wetting agent is sodium dodecyl sulfate.

[0030] The method for preparing the above-mentioned acid copper plating brightener comprises the following steps: According to the mass fractions, brightener, benzyl pyridinium chloride, wetting agent, hydroxyethyl cellulose and collagen were added into deionized water in turn and mixed well, heated to 80°C, stirred at a rate of 150 r / min for 2 h, and the acid copper plating brightener was obtained.

[0031] Example 2 An acid copper plating brightener comprises the following raw materials, measured by weight: 30 g of brightener, 8 g of pyridinium benzyl ammonium chloride, 50 g of wetting agent, 10 g of hydroxyethyl cellulose, 12 g of collagen, and 930 g of deionized water. The brightener is composed of sodium polydisulfide propane sulfonate, sodium thiazoline disulfide propane sulfonate, and methylene blue in a weight ratio of 5:3:2, and the wetting agent is fatty amine polyoxyethylene ether.

[0032] The method for preparing the above-mentioned acid copper plating brightener comprises the following steps: According to the mass fractions, brightener, benzyl pyridinium chloride, wetting agent, hydroxyethyl cellulose and collagen were added into deionized water in turn and mixed well, heated to 90°C, stirred at a rate of 180 r / min for 1 h to obtain an acid copper plating brightener.

[0033] Example 3 An acidic copper plating brightener comprises the following raw materials, measured by weight: 28 g of brightener, 7 g of pyridinium benzyl ammonium chloride, 45 g of wetting agent, 9.5 g of hydroxyethyl cellulose, 11 g of collagen, and 920 g of deionized water. The brightener is composed of sodium polydisulfide propane sulfonate, sodium thiazoline disulfide propane sulfonate, and methylene blue in a weight ratio of 5:3:2, and the wetting agent is polyethylene oxide polypropylene oxide monobutyl ether.

[0034] The method for preparing the above-mentioned acid copper plating brightener comprises the following steps: According to the mass fractions, brightener, benzyl pyridinium chloride, wetting agent, hydroxyethyl cellulose and collagen were added into deionized water in turn and mixed thoroughly, heated to 85°C, and stirred for 1.5h at a stirring rate of 160r / min to obtain an acid copper plating brightener.

[0035] Example 4 An acid copper plating brightener comprises the following raw materials, measured by weight: 28 g of brightener, 7 g of pyridinium benzyl ammonium chloride, 45 g of wetting agent, 9.5 g of hydroxyethyl cellulose, 9.5 g of collagen, and 920 g of deionized water. The brightener is composed of sodium polydisulfide propane sulfonate, sodium thiazoline disulfide propane sulfonate, and methylene blue in a weight ratio of 5:3:2, and the wetting agent is composed of sodium dodecyl sulfate, fatty amine polyoxyethylene ether, and polyethylene oxide polypropylene oxide monobutyl ether in a weight ratio of 5:8:2.

[0036] The method for preparing the above-mentioned acid copper plating brightener comprises the following steps: According to the mass fractions, brightener, benzyl pyridinium chloride, wetting agent, hydroxyethyl cellulose and collagen were added into deionized water in turn and mixed thoroughly, heated to 85°C, and stirred for 1.5h at a stirring rate of 160r / min to obtain an acid copper plating brightener.

[0037] Comparative Example 1 The same as Example 4, except that the brightener is sodium polydisulfide dipropane sulfonate.

[0038] Comparative Example 2 The same as Example 4, except that the brightener is sodium thiazoline disulfide propane sulfonate.

[0039] Comparative Example 3 The same as Example 4, except that the brightener is methylene blue.

[0040] Comparative Example 4 The same as Example 4, except that an equal amount of sodium polydipropane disulfide sulfonate produced by Wuhan Hechang Chemical Industry is used instead of the sodium polydipropane disulfide sulfonate prepared in Preparation Example 1 of the present application.

[0041] Performance Testing The acidic copper plating brighteners prepared in Examples 1 to 4 and Comparative Examples 1 to 4 were sampled and added to the copper electroplating solution. The formula of the copper electroplating solution was: Cu2 + (60±5)g / L, sulfuric acid (120±10)g / L, Cl - (50±10)mg / L, acid copper plating brightener 3mL / L, current density 30A / dm 2 , temperature (26±2)℃.

[0042] Sample 1: The copper foil was cut into 200mm×15mm samples using a special fixture, and then electroplated in the above copper electroplating solution after degreasing and activation treatment. The tensile strength, glossiness and elongation of the copper foil were tested. The test results are shown in Table 1.

[0043] Glossiness: The glossiness of the rough surface of the copper foil was measured using the WG-60G universal portable precision gloss meter produced by Shenzhen Weifu Optoelectronics Technology Co., Ltd. The projection angle was 60°, and three points were measured on the left, middle, and right sides of the rough surface of the copper foil, and the average value was taken. Tensile strength and elongation: The tensile strength and elongation are tested using the LD-1000A Class 1 electronic tensile testing machine produced by Jinan Jiazheng Instrument Manufacturing Co., Ltd. The tensile rate is 10mm / min. The tensile strength is required to be ≥280MPa and the elongation is ≥2%.

[0044] Test of deep plating ability of plating solution: Use the yellow tube insertion method to insert the brass sheet into a brass tube with a diameter of 10mm×100mm, seal one end, and place the open end of the brass tube perpendicular to the anode, 20mm away from the anode. Take it out after plating, and measure the length of the plating on the brass sheet to get the depth ability of the plating in the brass tube. The longer the length, the better the depth ability. The test results are shown in Table 1 below; Test of the throwing power of the plating solution: Using the HullCell test method, the test piece after chemical nickel plating is placed in the HullCell, and electroplated with a current of 1A for 60 minutes, and then the coating thickness in the center of the square is measured as required, and the plated HullCell test piece is divided into 4 areas, and the thickness of the center of squares 1-4 is measured respectively, and the throwing power is calculated according to the following formula: T = A × 100% / B, A is the coating thickness of any square in squares 2-4; B is the coating thickness in square 1; the test results are shown in Table 2 below.

[0045] Table 1 Performance test project Gloss (60°) Tensile strength / MPa Elongation / % Deep plating capacity / mm Example 1 249 383 2.8 44 Example 2 255 382 2.8 45 Example 3 258 393 2.9 47 Example 4 276 412 3.2 49 Comparative Example 1 213 357 2.5 41 Comparative Example 2 208 361 2.4 42 Comparative Example 3 223 358 2.6 40 Comparative Example 4 232 372 2.7 44 Table 2 Throwing power test Analyzing the data in Tables 1 and 2, we can see that: 1) The electroplated copper layer obtained by the acid copper plating brightener prepared in Example 1 to Example 4 has excellent gloss, tensile strength and elongation, as well as excellent throwing power and deep plating power, meeting the requirements for the conductivity of the through-hole plated of the circuit board.

[0046] 2) The performance comparison analysis of the acid copper plating brightener prepared in combination with Example 4 and Example 1-Example 3 shows that the wetting agent is composed of sodium dodecyl sulfate, fatty amine polyoxyethylene ether and polyethylene oxide polypropylene oxide monobutyl ether in a mass ratio of 5:8:2, and the synergistic effect between them is utilized to cooperate with each other to reduce the surface tension, improve the coverage of the solution on the substrate, and ensure that the copper ions are evenly distributed on the entire workpiece surface. Stabilize the plating solution to prevent copper ions from depositing too quickly in a specific area, thereby avoiding uneven coating and scorching. Control the crystallization process, promote the formation of fine and uniform grains, and improve the gloss and smoothness of the coating.

[0047] 3) The performance comparison analysis of the acidic copper plating brightener prepared in combination with Example 4 and Comparative Examples 1-3 shows that the brightener is composed of sodium polydisulfide propane sulfonate, sodium thiazoline disulfide propane sulfonate and methylene blue in a mass ratio of 5:3:2, and the synergistic effect between them is utilized to control the nucleation and growth of the copper layer in copper electrodeposition, refine the grains in the instantaneous nucleation process controlled by three-dimensional diffusion, improve the glossiness, and make the coating surface smoother and denser. Effective control of the copper electrodeposition process can be achieved to obtain an electroplated copper layer with excellent glossiness, tensile strength and elongation.

[0048] 4) The performance comparison analysis of the acidic copper plating brightener prepared in combination with Example 4 and Comparative Example 4 shows that the high-purity sodium polydisulfide dipropane sulfonate prepared in the present application can control the nucleation and growth of the copper layer in copper electrodeposition, refine the grains, and thus improve the glossiness of the copper plating layer. The synergistic effect of sodium polydisulfide dipropane sulfonate with hydroxyethyl cellulose and collagen can improve the tensile strength and elongation of the electroplated copper layer. The synergistic effect of sodium polydisulfide dipropane sulfonate with other wetting agents can make the copper plating grains more uniformly refined, and obtain uniformly sized, dense and fine grains, thereby improving the hole filling efficiency and the ability to plate and deep plating, and meeting the requirements for the through-hole conductivity of the circuit board.

[0049] The above embodiments are only used to explain the technical solutions of the present application rather than to limit them. Although the above embodiments provide a specific description of the present application, relevant technical personnel should understand that the specific implementation modes of the present invention can still be modified or replaced by equivalents, and any modifications and equivalent replacements that do not depart from the spirit and scope of the present application should be included in the scope of protection of the present application.

Claims

1. An acid copper plating brightener, characterized in that: The preparation raw materials include the following by weight: 25-30 parts of brightener, 6-8 parts of leveler, 40-50 parts of wetting agent, 7-10 parts of hydroxyethyl cellulose, 8-12 parts of collagen and 900-930 parts of deionized water.

2. The acid copper plating brightener according to claim 1, characterized in that: The mass ratio of the hydroxyethyl cellulose to the collagen is 1:

1.

3. The acid copper plating brightener according to claim 1, characterized in that: The brightener is composed of sodium polydisulfide propane sulfonate, sodium thiazoline disulfide propane sulfonate and methylene blue in a mass ratio of 5:3:

2.

4. The acid copper plating brightener according to claim 3, characterized in that: The preparation method of the polydisulfide sodium dipropane sulfonate comprises the following steps: S41, add 6L methanol and 1824g thiourea to an enamel kettle and stir evenly, cool to 20°C, slowly drop 2440g 1,3-propane sultone, control the dropwise addition temperature at 25-30°C, after the dropwise addition is completed, continue to react at 32°C for 4-5 hours, centrifuge, and dry to obtain 3-isothiourea propane sulfonic acid; S42, add 1980g3-isothiourea propanesulfonic acid to 8.3L 26% ammonia solution in an enamel kettle, heat to 60°C with stirring, stir until the salt is dissolved, cool to 13-15°C and keep for 1 hour, evaporate on a rotary evaporator until solid precipitates, cool to 13-15°C, and recrystallize with a mixed solvent of chloroform and isopropanol in a mass ratio of 1:1.3 to obtain 3-mercaptopropanesulfonic acid ammonium; S43, dissolving 1590g of 3-mercaptopropane ammonium sulfonate with 4L of distilled water, passing through an ion exchange resin, and the effluent is an aqueous solution of 3-mercaptopropane sulfonic acid. The column is washed with 6L of distilled water until the eluate is neutral to obtain an aqueous solution of 3-mercaptopropane sulfonic acid; S44, add 564g 30% hydrogen peroxide to the 3-mercaptopropanesulfonic acid aqueous solution, keep at 13-15°C for 8-10 hours, neutralize with 400g NaOH aqueous solution, evaporate the neutralized solution to dryness with a rotary evaporator to obtain high-purity sodium polydisulfide dipropane sulfonate.

5. The acid copper plating brightener according to claim 1, characterized in that: The leveling agent is benzyl pyridinium chloride.

6. The acid copper plating brightener according to claim 5, characterized in that: The preparation method of the pyridinium benzyl ammonium chloride comprises the following steps: adding pyridine into a reactor, heating to 50-60° C., stirring at 300 rpm for 1-2 hours, and adding benzyl chloride dropwise using a constant pressure dropping funnel, heating to 50-60° C., reflux reaction for 3-4 hours, transferring the product into a round beaker, and cooling to obtain a slightly light brown viscous liquid; and recrystallizing with petroleum ether and filtering to obtain the pyridinium benzyl ammonium chloride.

7. The acid copper plating brightener according to claim 6, characterized in that: The usage ratio of pyridine, benzyl chloride and petroleum ether is 1 mol: 1 mol: 550-600 mL.

8. The acid copper plating brightener according to claim 1, characterized in that: The wetting agent is at least one of sodium lauryl sulfate, fatty amine polyoxyethylene ether and polyethylene oxide polypropylene oxide monobutyl ether.

9. The acid copper plating brightener according to claim 8, characterized in that: The wetting agent is composed of sodium lauryl sulfate, fatty amine polyoxyethylene ether and polyethylene oxide polypropylene oxide monobutyl ether in a mass ratio of 5:8:

2.

10. A method for preparing an acid copper plating brightener according to any one of claims 1 to 9, characterized in that: The following steps are involved: According to the mass fractions, add the brightener, leveling agent, wetting agent, hydroxyethyl cellulose and collagen into deionized water in turn and mix them evenly. Heat to 80-90°C, keep the stirring speed at 150-180r / min and stir for 1-2h to obtain the acid copper plating brightener.

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