Electroplated copper leveler for surface repair and method of making same

Abstract

The application relates to the technical field of surface repair, in particular to a copper electroplating leveling agent for surface repair and a preparation method thereof. The application provides a copper electroplating leveling agent for surface repair, which is a pyridine derivative substituted polyacrylate compound with a structure shown in general formula (I). The leveling agent provided by the application takes polyacrylate as a main chain, and a side chain is connected with a 3-carboxylic acid-1-(2-hydroxyethyl) pyridinium cation unit through a urethane bond, thereby forming a unique bifunctional structure. A positive charge of a pyridine ring quaternary ammonium salt is a core adsorption site, can be precisely and directionally adsorbed in a high current density area of a through hole aperture, and can inhibit excessive deposition of copper, thereby fundamentally solving the problems of holes and recesses in through hole filling. A carboxyl group at a 3-position of the pyridine ring is a copper surface complexing site, can form a stable complex adsorption layer on a surface of an old copper layer, greatly improves the bonding force between a repaired plating layer and the old copper substrate, and perfectly adapts to a remanufacturing surface repair scene.

Description

Technical Field

[0001] This invention relates to the field of surface repair technology, specifically to an electroplated copper leveling agent for surface repair and its preparation method. Background Technology

[0002] Copper electroplating is a core process in electronic packaging manufacturing and printed circuit board (PCB) production, enabling interlayer interconnection, circuit construction, and via filling. Leveling agents are the key functional components in copper electroplating systems, determining the flatness of the plating layer and the effectiveness of via filling. With the rapid development of the electronics and information industry, the application of high aspect ratio and high-density packaging substrates is becoming increasingly widespread, placing higher demands on the leveling performance and via filling capabilities of copper electroplating leveling agents.

[0003] Currently, commonly used copper plating leveling agents in the industry mainly include dye-based agents (such as Janus Green B), polyquaternary ammonium salts, and imidazole derivatives. Among them, Janus Green B has a certain leveling effect, but it has drawbacks such as high toxicity, poor plating solution stability, and insufficient adaptability to high aspect ratio through-holes. Conventional polyquaternary ammonium salt leveling agents have problems such as poor adsorption selectivity, weak coating adhesion, and easy occurrence of voids and pinholes in through-hole filling, which cannot meet the electroplating requirements of high-precision packaging substrates.

[0004] Meanwhile, the remanufacturing and resource recycling of electronic waste has become an important direction for industry development, with copper layer remanufacturing and surface repair of waste packaging substrates and PCBs being a core component. Unlike electroplating on new substrates, remanufacturing surface repair presents unique challenges such as high surface roughness of the old copper layer, high impurity content in the substrate, and stringent requirements for plating adhesion. Existing conventional copper plating leveling agents are unsuitable for this scenario: on the one hand, existing leveling agents have weak adsorption and anchoring capabilities for the old copper layer, making it easy for the repaired plating to delaminate and peel off; on the other hand, metallic impurities introduced by the waste substrate can easily deactivate the leveling agent, significantly shortening the lifespan of the plating solution cycle, resulting in a low repair pass rate and failing to meet the production requirements of industrialized remanufacturing.

[0005] Currently, there is no dedicated electroplating copper leveling agent developed for the surface repair of electronic components in existing technologies. The technical pain points of conventional leveling agents in remanufacturing repair scenarios, such as poor adhesion of the repair layer, many defects in through-hole filling, weak resistance to impurities in the plating solution, and short service life, have not yet been effectively solved. Summary of the Invention

[0006] To address the aforementioned deficiencies in existing technologies, this application provides an electroplated copper leveling agent for surface repair and its preparation method. Through molecular structure design, a special leveling agent with strong leveling performance, high coating adhesion, and excellent plating solution stability is developed, perfectly meeting the process requirements for surface repair in the remanufacturing of electronic components.

[0007] In a first aspect, the present invention provides an electroplated copper leveling agent for surface repair, employing the following technical solution: An electroplating copper leveling agent for surface repair is a pyridine derivative-substituted polyacrylate compound having the structure shown in general formula (I): ; In the formula, n is the degree of aggregation, which takes the value of an integer 2 ≤ n ≤ 500.

[0008] By adopting the above technical solution, the leveling agent of the present invention has a polyacrylate main chain, and the side chain is connected to the 3-carboxylic acid-1-(2-hydroxyethyl)pyridinium cationic unit through urethane bonds, forming a unique bifunctional structure: the positive charge of the pyridine ring quaternary ammonium salt is the core adsorption site, which can be precisely and directionally adsorbed in the high current density region of the through hole opening, inhibiting excessive copper deposition and fundamentally solving the problem of voids and depressions in through hole filling (defect morphology is detailed in Figures 1 and 2); the carboxyl group at the 3 position of the pyridine ring is the copper surface complexation site, which can form a stable complex adsorption layer on the surface of the old copper layer, greatly improving the bonding force between the repair plating layer and the old copper substrate, and perfectly adapting to the surface repair scenario of remanufacturing. At the same time, the polyacrylate main chain endows the leveling agent with excellent water solubility and plating solution stability, which can withstand the impurity contamination in the remanufacturing scenario and greatly extend the service life of the plating solution cycle.

[0009] In one specific implementation, the degree of aggregation n is an integer of 10 ≤ n ≤ 400.

[0010] In one specific implementation scheme, the leveling agent has a number-average molecular weight of 3000 Da to 125000 Da and a polydispersity index of 1.2 to 1.4.

[0011] By adopting the above technical solution and optimizing the degree of polymerization and molecular weight range, the leveling agent has both excellent diffusion ability and adsorption inhibition ability in through-holes. It can achieve uniform diffusion in through-holes with high aspect ratios and form a stable adsorption layer in the high current region, thus adapting to the repair requirements of through-holes with different aspect ratios.

[0012] Secondly, this application provides a method for preparing an electroplated copper leveling agent for surface repair, employing the following technical solution: A method for preparing an electroplated copper leveling agent for surface repair includes the following steps: S1: Nucleophilic addition reaction, 3-carboxylic acid-1-(2-hydroxyethyl)pyridinium, ethyl isocyanate, catalyst and organic solvent are mixed and heated to 55-65℃ under nitrogen protection, and the reaction is maintained at this temperature for 4-5 h to obtain an intermediate solution containing acrylate functional monomers. S2: Free radical polymerization reaction. Add a free radical initiator to the intermediate solution, heat to 65-75℃, and keep the temperature for 10-16 hours to complete the polymerization reaction. S3: Post-processing: Remove organic solvent by vacuum distillation to obtain solid product. Dissolve the solid product and adjust the pH value to neutral. Filter and make up to volume to obtain the electroplating copper leveling agent used for surface repair.

[0013] By adopting the above technical solution, the preparation process is simple and the reaction conditions are mild, eliminating the need for complex separation and purification procedures, and enabling industrial-scale mass production. Furthermore, by adjusting the amount of initiator, reaction temperature, and time, the degree of polymerization and molecular weight of the product can be precisely controlled to meet the needs of different application scenarios.

[0014] In one specific implementation, the molar ratio of 3-carboxylic acid-1-(2-hydroxyethyl)pyridinium to isocyanate ethyl acrylate is 1:1.

[0015] In one specific feasible embodiment, the catalyst is dibutyltin dilaurate, and the amount used is 0.3% to 0.8% of the total mass of the reaction monomers.

[0016] In one specific implementation scheme, the free radical initiator is benzoyl peroxide, and the amount used is 0.1% to 1.0% of the total mass of the reactants.

[0017] In one specific implementation, the organic solvent is ethyl acetate.

[0018] Thirdly, this application provides an electroplating copper plating solution for surface repair, employing the following technical solution: An electroplating copper plating solution for surface repair includes a copper ion source, an acidic electrolyte, a chloride ion source, an accelerator, a wetting agent, and the aforementioned electroplating copper leveling agent for surface repair.

[0019] In one specific implementation scheme, the concentration of the electroplating copper leveling agent for surface repair is 1 ppm to 40 ppm based on the total volume of the plating solution.

[0020] In one specific feasible implementation, based on the total volume of the plating solution, the concentrations of each component are as follows: copper sulfate pentahydrate 45–65 g / L, sulfuric acid 50–70 g / L, chloride ions 50–80 ppm, sodium polydisulfide dipropane sulfonate 1–3 ppm, and polyethylene glycol 8000 300–800 ppm.

[0021] Fourthly, this application provides the application of the aforementioned electroplating copper solution in copper layer remanufacturing and surface repair, employing the following technical solution: The above-mentioned copper plating solution is used for the remanufacturing and surface repair of copper layers on waste electronic packaging substrates, PCBs, and copper electronic components. It is especially suitable for the remanufacturing and surface repair of through-hole copper layers with a thickness-to-diameter ratio of 3.5:1 to 15:1.

[0022] In summary, this application has the following beneficial effects: 1. This invention, through molecular structure design, enables the leveling agent to possess both strong adsorption sites of quaternary ammonium salts and carboxyl complexation sites, achieving excellent leveling and filling effects for through holes while significantly improving the adhesion between the repair plating and the old copper substrate. This solves the core problems of poor adhesion and easy delamination and detachment of existing leveling agents in remanufacturing and repair scenarios.

[0023] 2. The leveling agent of the present invention can achieve void-free filling of through holes with a thickness-to-diameter ratio of 3.5:1-15:1, and the coating surface is bright and delicate with high flatness. The plating solution has strong resistance to impurities and pollution, and long cycle life. It is suitable for the remanufacturing production requirements of waste electronic components of different specifications and has a wide process window.

[0024] 3. The preparation method of the present invention has mild reaction conditions and simple steps, requires no complex equipment or purification process, the product structure is controllable and the batch stability is good, and it can realize industrial mass production, which has extremely high industrial application value. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the void defect in the cross-section of the electroplated copper before surface repair; Figure 2 This is a schematic diagram of the concave defects on the electroplated copper surface before surface repair; Figure 3 The image shows a SEM image of the cross-section of the through hole after repair in Example 1 (magnification 500x, test voltage 15kV). Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments, comparative examples, and test data. The specific embodiments described herein are only used to explain the invention and are not intended to limit the invention.

[0027] Unless otherwise specified, all raw materials or components used in this application can be obtained through commercial channels. All raw materials comply with the requirements of the Product Quality Law of the People's Republic of China, the Regulations on the Safety Management of Hazardous Chemicals, the Safety Technical Specifications for Electroplating Chemicals (AQ 5202-2008), and relevant national standards for electronic-grade electroplating chemicals.

[0028] I. Raw Materials 1. 3-Carboxylic acid-1-(2-hydroxyethyl)pyridinium: electronic grade, purity ≥99%, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; 2. Ethyl isocyanate acrylate: electronic grade, purity ≥99%, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.; 3. Dibutyltin dilaurate (DBTDL): analytical grade, purchased from Sinopharm Chemical Reagent Co., Ltd.; 4. Benzoyl peroxide (BPO): Analytical grade, purchased from Sinopharm Chemical Reagent Co., Ltd. 5. Ethyl acetate: analytical grade, purchased from Sinopharm Chemical Reagent Co., Ltd.; 6. Copper sulfate pentahydrate: electronic grade, conforming to GB / T 31369-2015, purchased from Jiangxi Copper Corporation. 7. Sulfuric acid: electronic grade, conforming to GB / T 23840-2009, purchased from Sinopharm Chemical Reagent Co., Ltd.; 8. Hydrochloric acid: electronic grade, purchased from Sinopharm Chemical Reagent Co., Ltd. 9. Sodium polydisulfide dipropane sulfonate (SPS): Electroplating grade, purity ≥95%, purchased from Guangzhou Jialun Chemical Technology Co., Ltd. 10. Polyethylene glycol 8000 (PEG-8000): Electroplating grade, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. 11. Janus Green B: Analytical grade, purchased from Sinopharm Chemical Reagent Co., Ltd. 12. Commercially available conventional PCB repair copper plating leveling agent (polyquaternary ammonium salt): industrial grade, purchased from an electronic materials company in Shenzhen; 13. 20% dilute sulfuric acid solution: analytical grade, purchased from Sinopharm Chemical Reagent Co., Ltd.

[0029] II. Basic parent compound structure and synthetic route of leveling agent (P1) 1. Structural Formula (General Formula I): ; The degree of polymerization n is an integer of 2 ≤ n ≤ 500; the molecular structure is based on polyacrylate as the main chain, and the side chain is connected to the 3-carboxylic acid-1-(2-hydroxyethyl)pyridinium cationic unit through urethane bond; the nitrogen atom of the pyridine ring is a quaternary ammonium salt structure with a positive charge, which is the core adsorption site; the pyridine ring has a carboxyl functional group at the 3 position, which is the complexation site on the copper surface and is the core framework of the leveling function.

[0030] 2. Synthetic route Step 1 (nucleophilic addition reaction): 3-carboxylic acid-1-(2-hydroxyethyl)pyridinium reacts with ethyl isocyanate acrylate in a nucleophilic addition reaction catalyzed by dibutyltin dilaurate to generate acrylate functional monomers; Step 2 (Free radical polymerization): The above-mentioned acrylate functional monomers undergo free radical polymerization under the initiation of benzoyl peroxide to generate the target product base matrix leveling agent (P1).

[0031] III. Preparation Example Preparation of the base leveling agent (P1) in Example 1 (degree of polymerization n≈60) 1. Formula: 3-Carboxylic acid-1-(2-hydroxyethyl)pyridinium 8.36 g (50 mmol); ethyl isocyanate 7.06 g (50 mmol); dibutyltin dilaurate 77 mg; benzoyl peroxide 77 mg; ethyl acetate 40 mL.

[0032] 2. Preparation steps: S1. Under a nitrogen protective atmosphere, the prescribed amounts of 3-carboxylic acid-1-(2-hydroxyethyl)pyridinium, ethyl isocyanate, dibutyltin dilaurate and ethyl acetate were added to a dry two-necked flask and stirred until homogeneous to obtain a mixed reaction solution. S2. Heat the mixed reaction solution to 60°C, keep it at this temperature and stir for 4.5 hours to complete the nucleophilic addition reaction and obtain an intermediate solution containing acrylate functional monomers; S3. Add the formulated amount of benzoyl peroxide to the intermediate solution, stir and mix evenly, adjust the system temperature to 70℃, keep it at the temperature and stir for 12 hours to complete the free radical polymerization reaction; S4. After the reaction is complete, the ethyl acetate solvent in the system is removed by vacuum distillation, and the reaction solution is naturally cooled to room temperature to obtain the basic parent leveling agent (P1) solid product; S5. Product post-treatment: Dissolve the obtained solid product in deionized water, adjust the pH value to 7.0±0.2 with 20% dilute sulfuric acid solution, filter with 0.22μm microporous membrane and make up to volume to obtain a leveling agent aqueous solution for later use; S6. Product Characterization: By gel permeation chromatography (GPC, using polystyrene as standard and N,N-dimethylformamide as mobile phase), the number average molecular weight (Mn) of the obtained basic matrix leveling agent (P1) was approximately 18500 Da, the weight average molecular weight (Mw) was approximately 24200 Da, and the polydispersity index (PDI) was approximately 1.31. Based on the theoretical molecular weight of the repeating unit of the basic matrix leveling agent (P1) of this invention, which is 309.3 Da, the corresponding degree of polymerization n is approximately 60, falling within the range of 2 ≤ n ≤ 500. 1 H NMR (400 MHz, CDCl3) delta(ppm): 12.75 (s, 1H), 9.31 (s, 1H), 9.09 (d, 1H), 8.93 (d, 1H), 8.24 (t, 1H), 6.76 (t, 1H), 4.82 (t, 2H), 4.47 (t, 2H), 4.34 (t, 2H), 3.15 (m, 2H), 2.76 (m, 1H), 1.95 (t, 2H).

[0033] Elemental analysis (C 14 H 17 N2O6) n Theoretical values: C 54.37, H 5.54, N 9.06; Test values: C 54.20, H 5.58, N 9.15.

[0034] Preparation of the base leveling agent (P1) in Example 2 (degree of polymerization n≈10) The only difference between this preparation example and Preparation Example 1 is that the amount of benzoyl peroxide added is adjusted to 231 mg, the reaction temperature is adjusted to 80 °C, and the holding time for polymerization is adjusted to 8 hours; the rest of the raw material formulation and preparation steps are completely consistent with Preparation Example 1.

[0035] Product characterization: According to GPC analysis, the number average molecular weight Mn of the product is approximately 3100 Da, corresponding to a degree of polymerization n≈10, which falls within the range of 2≤n≤500.

[0036] Preparation of the base leveling agent (P1) in Example 3 (degree of polymerization n≈400) The only difference between this preparation example and Preparation Example 1 is that the amount of benzoyl peroxide added is adjusted to 25 mg, the reaction temperature is adjusted to 60 °C, and the holding time for polymerization is adjusted to 16 hours; the rest of the raw material formulation and preparation steps are completely consistent with Preparation Example 1.

[0037] Product characterization: According to GPC analysis, the number average molecular weight Mn of the product is approximately 123,700 Da, corresponding to a degree of polymerization n≈400, which falls within the range of 2≤n≤500.

[0038] IV. Examples Example 1: Preparation and application of an electroplating copper solution for surface repair 1. Raw material formula: 55 g copper sulfate pentahydrate; 60 g sulfuric acid; 0.067 g hydrochloric acid (equivalent to 65 ppm chloride ion concentration); 0.002 g sodium polydithiopropane sulfonate (equivalent to 2 ppm concentration); 0.5 g polyethylene glycol 8000 (equivalent to 500 ppm concentration); 0.02 g of the base matrix leveling agent (P1) prepared in Example 1 (equivalent to 20 ppm concentration); deionized water added to 1 L.

[0039] 2. Preparation steps: S1. Add 800 mL of deionized water to a clean plating tank, add the prescribed amount of sulfuric acid, stir and mix evenly to obtain an acidic base solution; S2. Add the prescribed amount of copper sulfate pentahydrate to the acidic base solution, stir until completely dissolved, and cool to room temperature; S3. Add the prescribed amounts of hydrochloric acid, sodium polydithiopropane sulfonate, and polyethylene glycol 8000 to the above solution in sequence, and stir until completely mixed; S4. Add the formulated amount of base leveling agent (P1) to the solution and stir to mix evenly; S5. Add deionized water to bring the volume to 1L to obtain the electroplating copper plating solution for surface repair.

[0040] The plating solution prepared in this embodiment is used for surface repair of the copper layer of the through hole in the waste packaging substrate. The substrate parameters are: through hole diameter 100±15μm, hole depth 350±20μm, thickness-to-diameter ratio 3.5:1. The original through hole copper layer has peeling and void defects. The micro morphology of the copper layer of the through hole cross section after repair in this embodiment is shown in Figure 3.

[0041] Example 2: Preparation and application of an electroplating copper solution for surface repair The only difference between this embodiment and Embodiment 1 is that the amount of the base leveling agent (P1) added is 1 ppm, which is equivalent to a concentration of 1 ppm in the plating solution. The other raw material formulations, preparation steps, and repair application scenarios are completely consistent with Embodiment 1.

[0042] Example 3: Preparation and application of an electroplating copper solution for surface repair The only difference between this embodiment and Example 1 is that the amount of base leveling agent (P1) added is 40 ppm, which is equivalent to a concentration of 40 ppm in the plating solution. The other raw material formulations, preparation steps, and repair application scenarios are completely consistent with Example 1.

[0043] Example 4: Preparation and application of an electroplating copper solution for surface repair The only difference between this embodiment and Embodiment 1 is that the plating solution is used for repairing ultra-high aspect ratio through holes with an aspect ratio of 15:1, the substrate parameters are through hole diameter of 80μm and hole depth of 1200μm, and the original through hole copper layer has peeling and void defects. The rest of the raw material formula and preparation steps are completely consistent with Embodiment 1.

[0044] Example 5: Preparation and application of an electroplating copper solution for surface repair The only difference between this embodiment and Example 1 is that the base leveling agent (P1) (n≈10) prepared in Example 2 is used to replace the product in Example 1. The other raw material formulations, preparation steps and repair application scenarios are completely consistent with Example 1.

[0045] Example 6: Preparation and application of an electroplating copper solution for surface repair The only difference between this embodiment and Example 1 is that the base leveling agent (P1) (n≈400) prepared in Example 3 is used to replace the product in Example 1. The other raw material formulations, preparation steps and repair application scenarios are completely consistent with Example 1.

[0046] Example 7: Preparation and application of an electroplating copper solution for surface repair The only difference between this embodiment and Embodiment 1 is that the plating solution is used for the surface repair of the copper layer of the lead frame of a waste integrated circuit, the substrate is a copper lead frame, and the surface has oxidation corrosion and wear defects. The other raw material formulas and preparation steps are completely consistent with Embodiment 1.

[0047] V. Comparative Examples Comparative Example 1 The only difference between this comparative example and Example 1 is that commercially available Genagreen B is used to replace the base matrix leveling agent (P1). The amount added, the formulation of other raw materials, the preparation steps, and the repair application scenarios are completely consistent with Example 1.

[0048] Comparative Example 2 The only difference between this comparative example and Example 1 is that no leveling agent is added; the rest of the raw material formulation, preparation steps, and repair application scenarios are completely consistent with Example 1.

[0049] Comparative Example 3 The only difference between this comparative example and Example 1 is that a commercially available conventional PCB repair electroplating copper leveling agent (polyquaternary ammonium salt) is used instead of the base leveling agent (P1). The amount added, the formulation of other raw materials, the preparation steps and the repair application scenarios are completely consistent with Example 1.

[0050] Comparative Example 4 The only difference between this comparative example and Example 4 is that commercially available Genagreen B is used to replace the base matrix leveling agent (P1). The amount added, the formulation of other raw materials, the preparation steps, and the repair application scenarios are completely consistent with Example 4.

[0051] VI. Testing Methods All test samples were processed using standardized electroplating repair parameters: plating bath temperature 24℃, current density 1.5A / dm², and plating time 120 minutes. The testing methods are as follows: 1. Evaluation of coating appearance: The visual observation method is used to evaluate whether the surface of the electroplated coating is bright and smooth, and whether there are defects such as pinholes, pits, and peeling. 2. Evaluation of via filling voids: The cross-section of the vias of the substrate after electroplating repair was observed using a metallographic microscope. The percentage of qualified vias without voids, cracks, or gaps was counted out of 100 tested vias, and the repair qualification rate was calculated. 3. Coating depression value test: The coating depression value on the surface of the repaired through hole was tested using a laser confocal microscope. Ten points were tested for each sample, and the average value was taken. The unit is μm. 4. Coating adhesion test: According to GB / T 5270-2024 "Review of test methods for adhesion strength of electrodeposited and chemically deposited metal coatings on metal substrates", the adhesion between the repaired coating and the old copper substrate was tested by scratch method combined with thermal cycling method. The maximum adhesion value of the coating without peeling or falling off was recorded, and the unit is N / mm. 5. Plating solution cycle life test: A continuous electroplating cycle test was conducted using a Harlin tank. Each cycle lasted 120 minutes. The number of cycles when the plating solution repair qualification rate first fell below 95% was recorded, which is the plating solution cycle life. 6. Coating surface roughness test: In accordance with GB / T 1031-2009 "Product Geometric Specification (GPS) Surface Structure Profile Method Surface Roughness Parameters and Their Values", the surface roughness Ra value of the repaired coating was tested using a white light interferometer, with the unit being μm.

[0052] VII. Test Results ; Example 7 is a planar repair of the lead frame, without any through-hole filling related indicators, so the corresponding position is marked with "-".

[0053] VIII. Results Analysis 1. The copper leveling agents for surface repair prepared in all embodiments of this invention can be precisely adsorbed onto the high current density region by the positively charged groups of pyridine quaternary ammonium salt, and the carboxyl functional groups complex with the copper deposition surface, achieving precise control of the copper deposition rate. This solves the technical problems of excessive deposition at the orifice and voids easily appearing in the through-hole filling during the electroplating process. Examples 1, 5, and 6 all achieved a through-hole repair qualification rate of over 96%, proving that within the polymerization degree range of 2≤n≤500 defined in the claims of this invention, excellent leveling effects can be achieved, and the scope of protection of the claims is sufficiently supported by the embodiments. Examples 1-3 all achieved excellent plating effects, proving that the addition amount range of 1-40 ppm can meet the surface repair process requirements.

[0054] 2. Comparing the test results of Example 1 with Comparative Examples 1 and 3, it can be seen that the leveling agent of the present invention has significant improvements over existing commercially available conventional dye-based and polyquaternary ammonium salt-based leveling agents in terms of through-hole repair qualification rate, coating smoothness, adhesion, and plating solution lifespan. The core reason is that the leveling agent of the present invention uses polyacrylate as the main chain, which combines the strong adsorption of pyridine quaternary ammonium salt with the copper surface complexation of carboxyl groups. It can form a gradient adsorption layer on the copper surface, which not only inhibits excessive deposition in the high current area of ​​the hole, but also does not hinder the normal deposition of copper inside the hole. It fundamentally solves the technical pain points of existing remanufacturing surface repair processes, such as poor adhesion of the repair layer, easy occurrence of voids in through-holes, poor stability of plating solution, and short service life.

[0055] 3. Comparing the test results of Example 1 and Comparative Example 2, it can be seen that the electroplating solution without adding leveling agent cannot effectively fill the through holes, and the plating quality is extremely poor, which further proves the core role of the leveling agent of the present invention in the electroplated copper surface repair process.

[0056] 4. The repair test results of Example 4 for 15:1 ultra-high aspect ratio through holes and Example 7 for lead frame surface repair test results show that the leveling agent of the present invention can be adapted to remanufacturing repair scenarios of through holes with different aspect ratios and different copper substrates, and has a wide range of process applications, which can meet the remanufacturing production requirements of waste electronic components and copper precision parts.

[0057] In summary, this specification provides a clear and complete description of the chemical structure, preparation method, performance testing, and application effects of the leveling agent. Those skilled in the art can replicate the technical solution of this invention, solve the technical problems it raises, and achieve the expected technical effects by following the content disclosed in this specification.

Claims

1. A copper plating leveling agent for surface repair, characterized in that, The leveling agent is a pyridine derivative-substituted polyacrylate compound having the structure shown in general formula (I): ； In the formula, n is the degree of aggregation, which takes the value of an integer of 10 ≤ n ≤ 400.

2. The electroplating copper leveling agent for surface repair according to claim 1, characterized in that, The leveling agent has a number-average molecular weight of 3000 Da to 125000 Da and a polydispersity index of 1.2 to 1.

4.

3. A method for preparing the electroplated copper leveling agent for surface repair as described in claim 1, characterized in that, Includes the following steps: S1: Nucleophilic addition reaction, 3-carboxylic acid-1-(2-hydroxyethyl)pyridinium, ethyl isocyanate, catalyst and organic solvent are mixed and heated to 55-65℃ under nitrogen protection, and the reaction is maintained at this temperature for 4-5 h to obtain an intermediate solution containing acrylate functional monomers. S2: Free radical polymerization reaction. Add a free radical initiator to the intermediate solution, heat to 65-75℃, and keep the temperature for 10-16 hours to complete the polymerization reaction. S3: Post-processing: Remove organic solvent by vacuum distillation to obtain solid product. Dissolve the solid product and adjust the pH value to neutral. Filter and make up to volume to obtain the electroplating copper leveling agent used for surface repair.

4. The method for preparing the electroplated copper leveling agent for surface repair according to claim 3, characterized in that, The molar ratio of 3-carboxylic acid-1-(2-hydroxyethyl)pyridinium to isocyanate ethyl acrylate is 1:1; the catalyst is dibutyltin dilaurate, and the amount used is 0.3% to 0.8% of the total mass of the reactants; the free radical initiator is benzoyl peroxide, and the amount used is 0.1% to 1.0% of the total mass of the reactants; the organic solvent is ethyl acetate.

5. A copper plating solution for surface repair, characterized in that, It includes a copper ion source, an acidic electrolyte, a chloride ion source, an accelerator, a wetting agent, and the electroplating copper leveling agent for surface repair as described in any one of claims 1-2.

6. The electroplating copper plating solution for surface repair according to claim 5, characterized in that, The concentration of the electroplating copper leveling agent used for surface repair is 1 ppm to 40 ppm based on the total volume of the plating solution.

7. The electroplating copper solution for surface repair according to claim 5, characterized in that, Based on the total volume of the plating solution, the concentrations of each component are as follows: copper sulfate pentahydrate 45–65 g / L, sulfuric acid 50–70 g / L, chloride ions 50–80 ppm, sodium polydisulfide dipropane sulfonate 1–3 ppm, and polyethylene glycol 8000 300–800 ppm.

8. The electroplating copper plating solution for surface repair according to claim 5, characterized in that, The application scenarios for the plating solution are the remanufacturing and surface repair of copper layers on waste electronic packaging substrates, PCBs, and copper electronic components.

9. The electroplating copper plating solution for surface repair according to claim 8, characterized in that, The plating solution is suitable for surface repair of through-hole copper layers with thickness-to-diameter ratios of 3.5:1 to 15:1 during remanufacturing.

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