Electroplating solution for HDI board hole filling and preparation method

Abstract

This application relates to the field of electroplating solution processing technology, and more specifically, to an electroplating solution for filling holes in HDI boards and its preparation method. The solution is prepared from the following raw materials in parts by weight: 120-240 parts copper salt, 10-15 parts complexing agent, 5-10 parts leveling agent, 45-70 parts sulfuric acid, 10-20 parts stabilizer, 10-20 parts surfactant, 5-10 parts pH adjuster, 8-12 parts accelerator, 8-12 parts brightener, and 1000 parts water. The stabilizer is composed of 2-mercaptobenzothia and dimethyldimercaptoacetic acid isooctyl tin. The surfactant is composed of oleyl alcohol polyoxyethylene carboxylate, hexadecylpyridine chloride, and sodium cocoyl glutamate. The electroplating solution for filling holes in HDI boards prepared using this formula effectively solves the problems of poor permeability and uneven current distribution encountered in blind hole copper filling during HDI board electroplating, thereby significantly improving the quality and reliability of the plating layer.

Description

Technical Field

[0001] This application relates to the field of electroplating solution processing technology, and more specifically, to an electroplating solution for filling holes in HDI boards and a method for its preparation. Background Technology

[0002] HDI boards, or high-density interconnect boards, are circuit boards with high circuit density that utilize micro-blind via technology. HDI boards have inner and outer layers of circuitry, and processes such as drilling and in-hole metallization are used to connect the internal circuitry of each layer. Among these processes, blind via electroplating is one of the key technologies for achieving electrical interconnection between HDI board layers. This technology not only ensures the electrical interconnection performance of the blind vias but also affects the overall quality and production efficiency of the HDI board.

[0003] Compared to traditional multilayer boards, HDI boards have significantly smaller via and blind via diameters. During the electroplating process, as the thickness-to-diameter ratio (depth to diameter ratio) of the blind via gradually increases, the difficulty of copper plating within the via also increases. This is because the smaller the via diameter, the poorer the permeability of the plating solution within the via. The plating solution cannot penetrate evenly and fully into all corners of the via, resulting in insufficient copper plating or uneven plating in certain areas, thus affecting the quality and reliability of the plating layer. Simultaneously, during electroplating, the current distribution within the via exhibits a drum-shaped pattern, meaning high current density at the via edges and low current density in the center. As the thickness-to-diameter ratio of the blind via increases, this uneven current distribution becomes more pronounced. This can lead to excessively thick plating at the via edges and insufficient plating in the center, or even no plating at all. Summary of the Invention

[0004] To improve the problem of poor permeability of electroplating solution in holes, this application provides an electroplating solution for filling holes in HDI boards and a preparation method thereof.

[0005] In a first aspect, this application provides an electroplating solution for filling holes in an HDI board, employing the following technical solution:

[0006] An electroplating solution for filling vias in HDI boards is prepared from the following raw materials in parts by weight:

[0007] 120-240 parts copper salt

[0008] 10-15 parts of complexing agent

[0009] 5-10 parts of leveling agent

[0010] 45-70 parts of sulfuric acid

[0011] stabilizer 10-20 parts

[0012] 10-20 parts of surfactant

[0013] 5-10 parts pH adjuster

[0014] 8-12 parts of accelerator

[0015] 8-12 parts of brightener

[0016] 1000 portions of water

[0017] The stabilizer is composed of 2-mercaptobenzothia and tin isooctyl dimethyldimercaptoacetate;

[0018] The surfactant is composed of oleyl alcohol polyoxyethylene carboxylate, hexadecylpyridine chloride, and sodium cocoyl glutamate.

[0019] By adopting the above technical solution, the problems of poor permeability and uneven current distribution encountered in the blind hole copper filling process of HDI board electroplating are effectively solved, thereby significantly improving the quality and reliability of the coating.

[0020] By using a mixture of oleyl alcohol polyoxyethylene carboxylate, hexadecylpyridine chloride, and sodium cocoyl glutamate, the surface tension of the electroplating solution is effectively reduced, enhancing its penetration ability in blind holes. This allows the electroplating solution to penetrate more evenly and fully into every corner of the blind holes, significantly reducing the risk of insufficient copper plating or uneven plating.

[0021] The addition of a leveling agent helps suppress copper deposition in high current density areas, while a brightener promotes a bright and smooth coating. The synergistic effect of the leveling and brighteners helps mitigate the negative impact of uneven current distribution, i.e., the phenomenon of excessively thick coating at the hole edges and insufficient coating in the center, thus improving the overall uniformity of the coating. The concentration range of copper salts in the formulation ensures a sufficient supply of copper ions to meet the requirements of copper plating. Simultaneously, the use of a complexing agent effectively stabilizes the morphology of copper ions, preventing their precipitation or aggregation during electroplating, further improving the uniformity and stability of the coating.

[0022] The stabilizer, composed of 2-mercaptobenzothia and tin isooctyl dimethyldimercaptoacetate, provides dual protection during electroplating. On one hand, it prevents oxidation and corrosion of the plating layer during electroplating; on the other hand, it stabilizes the copper ion concentration in the electroplating solution, preventing copper ion precipitation and aggregation. This dual protection ensures the stability and durability of the plating layer. By adding an appropriate amount of pH adjuster, the acidity or alkalinity of the electroplating solution can be precisely controlled, thereby ensuring the stability and controllability of the electroplating process.

[0023] Preferably, the weight ratio of the oleyl alcohol polyoxyethylene carboxylate, the hexadecylpyridine chloride, and the sodium cocoyl glutamate is (4-8):(2-4):3.

[0024] By adopting the above technical solution and optimizing the dosage of oleyl alcohol polyoxyethylene carboxylate, hexadecylpyridine chloride, and sodium cocoyl glutamate, the efficient synergistic effect of the surfactant in the electroplating solution is further ensured, enhancing the penetration performance of the electroplating solution. This allows the electroplating solution to penetrate more fully into the blind holes, improving the uniformity and integrity of the copper plating. Secondly, this ratio also helps optimize the current distribution within the holes, reducing defects and porosity in the plating layer, thereby improving the overall quality and reliability of the plating layer.

[0025] Preferably, the weight ratio of the 2-mercaptobenzothia to the dimethyldimercaptoacetic acid isooctyl tin is (3-6):4.

[0026] By adopting the above technical solution and optimizing the dosage of 2-mercaptobenzothia and tin isooctyl dimethyldimercaptoacetate, it is ensured that the stabilizer can fully exert its antioxidant and anti-corrosion effects during the electroplating process, effectively protecting the coating from oxidation and corrosion, thereby improving the durability and stability of the coating.

[0027] Secondly, this ratio also helps to stabilize the concentration of copper ions in the electroplating solution, prevent the precipitation and aggregation of copper ions, ensure the smooth progress of the electroplating process, and further improve the quality and uniformity of the coating.

[0028] Preferably, the leveling agent is at least one of dimethylpyrazole, sodium tartrate, 3-mercaptopropane-1-sulfonic acid, 2-amino-3-pyridinethiol, 6-amino-2-naphthylthiol and 3-(dimethylamino)-1-propanethiol.

[0029] By adopting the above technical solutions and optimizing the type of leveling agent, the uneven distribution of current within the holes can be significantly improved. This ensures uniform deposition of the plating layer throughout the holes, preventing excessively thick plating at the edges and insufficient or no plating in the center, thus improving the uniformity and integrity of the plating layer. Simultaneously, these leveling agents also optimize the surface tension of the plating solution, further enhancing its penetration performance and ensuring complete penetration into the blind holes, thereby improving the efficiency and effectiveness of copper plating.

[0030] Preferably, the leveling agent is composed of dimethylpyrazole, 3-mercaptopropane-1-sulfonic acid and 2-amino-3-pyridinethiol in a weight ratio of (5-8):(2-4):3.

[0031] By adopting the above technical solution, the leveling agent can fully exert its role in regulating current distribution, resulting in a more uniform current distribution within the holes during electroplating. This effectively avoids uneven plating thickness and significantly improves the uniformity and consistency of the plating layer. Simultaneously, this combination enhances the penetration performance of the plating solution, allowing it to penetrate more fully into the blind holes, ensuring efficient copper plating and further improving the quality and reliability of the plating layer.

[0032] Preferably, the copper salt includes at least one of copper sulfate, copper nitrate, copper bromide, copper methanesulfonate, and copper chloride.

[0033] By adopting the above technical solution, an abundant source of copper ions is provided, ensuring a stable supply of copper ions during the electroplating process. This provides a sufficient material basis for the formation of the coating and helps to optimize the electrochemical performance of the electroplating solution. As a result, the electroplating solution can adapt to the copper filling requirements of blind holes with different pore sizes and thickness-to-diameter ratios, thereby improving electroplating efficiency and coating quality.

[0034] Preferably, the brightener is composed of sodium polydisulfide dipropane sulfonate, pyridinepropyl sulfobetaine and potassium 3-mercapto-1-ethyl sulfonate in a weight ratio of (4-6):(1-2):5.

[0035] By adopting the above technical solution, the brightener can fully exert its brightening effect, significantly improve the gloss and brightness of the coating, make the coating surface smoother and brighter, and enhance the decorative and aesthetic properties of the coating.

[0036] Meanwhile, this combination also exhibits excellent wetting and dispersibility, which helps improve the flowability and penetration performance of the electroplating solution, allowing it to more evenly cover the substrate surface and further enhancing the uniformity and density of the coating. Furthermore, this brightener combination demonstrates good stability and compatibility, enabling it to synergistically work with other components in the electroplating solution to jointly improve electroplating efficiency and coating quality.

[0037] Preferably, the complexing agent is obtained by mixing hydroxyethylidene diphosphonic acid and tartaric acid in a weight ratio of (4-8):3.

[0038] By adopting the above technical solution, the complexing agent can effectively complex with copper ions to form a stable complex, thereby preventing the hydrolysis or precipitation of copper ions during electroplating and ensuring the stability of the electroplating solution and the quality of the coating. Simultaneously, the synergistic effect of hydroxyethylidene diphosphonic acid and tartaric acid enhances the buffering capacity of the electroplating solution, helps regulate the pH value of the solution, and keeps it within a suitable range, further improving the stability and controllability of the electroplating process, and contributing to improved uniformity and density of the coating.

[0039] Preferably, the pH adjuster includes one of phosphoric acid, pyrophosphate, and citric acid.

[0040] By adopting the above technical solutions, the pH of the electroplating solution can be effectively adjusted and maintained within a suitable range, thereby ensuring the stability of the electroplating process and the quality of the coating. Phosphoric acid and pyrophosphoric acid also have strong coordination properties, enabling them to form stable complexes with copper ions, preventing copper ions from precipitating during electroplating and further improving the stability of the electroplating solution. Secondly, these pH adjusters also have a certain buffering effect, resisting acid-base changes during electroplating and maintaining the relative stability of the pH value of the electroplating solution, making the electroplating process more controllable.

[0041] Secondly, this application provides a method for preparing an electroplating solution for filling holes in an HDI board, using the following technical solution:

[0042] A method for preparing an electroplating solution for filling holes in HDI boards involves uniformly mixing copper salt, complexing agent, leveling agent, sulfuric acid, stabilizer, pH adjuster, surfactant, brightener, and water to obtain the electroplating solution for filling holes in HDI boards.

[0043] By adopting the above technical solution, the prepared electroplating solution possesses excellent hole-filling ability and coating quality. It can uniformly and efficiently fill the tiny blind holes in HDI boards, ensuring uniform distribution of the coating inside and outside the holes, and avoiding problems such as uneven coating thickness and porosity. Simultaneously, the electroplating solution also exhibits good stability and operability, maintaining stable electroplating results within a wide range of process parameters, thus reducing the failure rate and defect rate during the electroplating process.

[0044] In summary, this application has the following beneficial effects:

[0045] 1. This application describes an electroplating solution prepared by mixing copper salt, complexing agent, leveling agent, sulfuric acid, stabilizer, pH adjuster, surfactant, brightener, and water in a specific ratio for filling holes in HDI boards. This solution can effectively solve the problems of poor permeability and uneven current distribution in the electroplating process of filling holes in HDI boards. In other words, through the carefully designed ratio and combination of raw materials, the permeability of the electroplating solution is significantly improved, the current distribution is optimized, and the coating quality and electroplating efficiency are enhanced. Detailed Implementation

[0046] Example

[0047] Example 1

[0048] An electroplating solution for filling vias in HDI boards is prepared by the following method:

[0049] 120g of copper salt (copper sulfate), 10g of complexing agent (hydroxyethylidene diphosphonic acid), 5g of leveling agent (dimethylpyrazole), 45g of sulfuric acid, 10g of stabilizer, 5g of pH adjuster (phosphoric acid), 10g of surfactant, 8g of brightener (sodium polydisulfide dipropane sulfonate) and 1000g of water are mixed evenly to obtain an electroplating solution for filling holes in HDI boards.

[0050] The stabilizer is composed of 2-mercaptobenzothia and tin isooctyl dimethyldimercaptoacetate in a weight ratio of 3:4.

[0051] The surfactant is composed of oleyl alcohol polyoxyethylene carboxylate, hexadecylpyridine chloride and sodium cocoyl glutamate in a weight ratio of 4:2:3, and the oleyl alcohol polyoxyethylene carboxylate is sodium oleyl alcohol polyoxyethylene carboxylate.

[0052] Example 2

[0053] An electroplating solution for filling vias in HDI boards is prepared by the following method:

[0054] 180g of copper salt (copper nitrate), 13g of complexing agent (sodium potassium tartrate), 8g of leveling agent (sodium tartrate), 60g of sulfuric acid, 15g of stabilizer, 8g of pH adjuster (pyrophosphate), surfactant, 10g of brightener (pyridinepropyl sulfobetaine), and 1000g of water are mixed evenly to obtain an electroplating solution for filling holes in HDI boards.

[0055] The stabilizer is composed of 2-mercaptobenzothia and tin isooctyl dimethyldimercaptoacetate in a weight ratio of 5:4.

[0056] The surfactant is composed of oleyl alcohol polyoxyethylene carboxylate, hexadecyl pyridine chloride, and sodium cocoyl glutamate in a weight ratio of 6:3:3.

[0057] Example 3

[0058] An electroplating solution for filling vias in HDI boards is prepared by the following method:

[0059] A plating solution for filling holes in HDI boards is prepared by mixing 240g of copper salt (copper bromide), 15g of complexing agent (diethylenetriaminepentaacetic acid), 10g of leveling agent (2-amino-3-pyridinethiol), 70g of sulfuric acid, 20g of stabilizer, 10g of pH adjuster (citric acid), 20g of surfactant, 12g of brightener (potassium 3-mercapto-1-ethylsulfonate), and 1000g of water.

[0060] The stabilizer is composed of 2-mercaptobenzothia and dimethyldimercaptoacetic acid isooctyl tin in a weight ratio of 6:4.

[0061] The surfactant is composed of oleyl alcohol polyoxyethylene carboxylate, hexadecyl pyridine chloride, and sodium cocoyl glutamate in a weight ratio of 8:4:3.

[0062] Example 4

[0063] An electroplating solution for filling holes in HDI boards, the difference between this embodiment and Example 1 is that the weight ratio of oleyl alcohol polyoxyethylene carboxylate, hexadecyl pyridine chloride and sodium cocoyl glutamate is 2:2:3.

[0064] Example 5

[0065] An electroplating solution for filling holes in HDI boards, the difference between this embodiment and Example 1 is that the weight ratio of oleyl alcohol polyoxyethylene carboxylate, hexadecyl pyridine chloride and sodium cocoyl glutamate is 4:2:4.

[0066] Example 6

[0067] An electroplating solution for filling vias in HDI boards, differing from Example 1 in that the weight ratio of 2-mercaptobenzothiol and tin isooctyl dimethyldimercaptoacetate is 3:3. (The amount of tin isooctyl dimethyldimercaptoacetate is reduced.)

[0068] Example 7

[0069] An electroplating solution for filling holes in HDI boards, the difference between this embodiment and Example 1 is that the leveling agent is composed of dimethylpyrazole, 3-mercaptopropane-1-sulfonic acid and 2-amino-3-pyridinethiol in a weight ratio of 8:2:3.

[0070] Example 8

[0071] An electroplating solution for filling holes in HDI boards, the difference between this embodiment and Example 1 is that the leveling agent is composed of dimethylpyrazole, 3-mercaptopropane-1-sulfonic acid and 2-amino-3-pyridinethiol in a weight ratio of 8:4:3.

[0072] Example 9

[0073] An electroplating solution for filling holes in HDI boards, the difference between this embodiment and Example 7 is that the leveling agent is composed of dimethylpyrazole and 3-mercaptopropane-1-sulfonic acid in a weight ratio of 8:4.

[0074] Example 10

[0075] An electroplating solution for filling holes in HDI boards, the difference between this embodiment and Example 7 is that the leveling agent is composed of dimethylpyrazole and 2-amino-3-pyridinethiol in a weight ratio of 8:3.

[0076] Example 11

[0077] An electroplating solution for filling holes in HDI boards, the difference between this embodiment and Example 1 is that the brightener is composed of sodium polydithiopropane sulfonate, pyridinepropyl sulfobetaine and potassium 3-mercapto-1-ethyl sulfonate in a weight ratio of 4:1:5.

[0078] Example 12

[0079] An electroplating solution for filling holes in HDI boards, the difference between this embodiment and Example 7 is that the brightener is composed of sodium polydithiopropane sulfonate, pyridinepropyl sulfobetaine and potassium 3-mercapto-1-ethyl sulfonate in a weight ratio of 6:2:5.

[0080] Example 13

[0081] An electroplating solution for filling holes in HDI boards, the difference between this embodiment and Example 11 is that the brightener is composed of sodium polydithiopropane sulfonate and pyridinepropyl sulfobetaine in a weight ratio of 6:2.

[0082] Example 14

[0083] An electroplating solution for filling holes in HDI boards, the difference between this embodiment and Example 11 is that the brightener is composed of sodium polydithiopropane sulfonate and potassium 3-mercapto-1-ethylsulfonate in a weight ratio of 6:5.

[0084] Example 15

[0085] An electroplating solution for filling holes in HDI boards, the difference between this embodiment and Example 1 is that the complexing agent is obtained by mixing hydroxyethylidene diphosphonic acid and tartaric acid in a weight ratio of 4:3.

[0086] Example 16

[0087] An electroplating solution for filling holes in HDI boards, the difference between this embodiment and Example 12 is that the complexing agent is obtained by mixing hydroxyethylidene diphosphonic acid and tartaric acid in a weight ratio of 8:3.

[0088] Example 17

[0089] An electroplating solution for filling holes in HDI boards, the difference between this embodiment and embodiment 15 is that the complexing agent is obtained by mixing hydroxyethylidene diphosphonic acid and tartaric acid in a weight ratio of 4:4.

[0090] Comparative Example

[0091] Comparative Example 1

[0092] An electroplating solution for filling holes in HDI boards, the difference between this comparative example and Example 1 is that no surfactant is added.

[0093] Comparative Example 2

[0094] An electroplating solution for filling holes in HDI boards. The difference between this comparative example and Example 1 is that the surfactant is composed of oleyl alcohol polyoxyethylene carboxylate and hexadecyl pyridine chloride in a weight ratio of 4:2.

[0095] Comparative Example 3

[0096] An electroplating solution for filling holes in HDI boards. The difference between this comparative example and Example 1 is that the surfactant is composed of oleyl alcohol polyoxyethylene carboxylate and sodium cocoyl glutamate in a weight ratio of 4:3.

[0097] Comparative Example 4

[0098] An electroplating solution for filling holes in HDI boards, the difference between this comparative example and Example 1 is that the surfactant is composed of hexadecylpyridine chloride and sodium cocoyl glutamate in a weight ratio of 2:3.

[0099] Comparative Example 5

[0100] An electroplating solution for filling holes in HDI boards. The difference between this comparative example and Example 1 is that the surfactant is oleyl alcohol polyoxyethylene carboxylate.

[0101] Comparative Example 6

[0102] An electroplating solution for filling holes in HDI boards, the difference between this comparative example and Example 1 is that no stabilizer is added.

[0103] Comparative Example 7

[0104] An electroplating solution for filling holes in HDI boards, the difference between this comparative example and Example 1 is that the stabilizer is 2-mercaptobenzothiol.

[0105] Comparative Example 8

[0106] An electroplating solution for filling holes in HDI boards. The difference between this comparative example and Example 1 is that the stabilizer is tin isooctyl dimethyl mercaptoacetate.

[0107] Comparative Example 9

[0108] An electroplating solution for filling holes in HDI boards, the difference between this comparative example and Example 1 is that no pH adjuster is added.

[0109] Detection methods / test methods

[0110] Test plates with blind holes of the same size and specifications (taking a 125×75μm blind hole type as an example) were placed in the electroplating solutions provided in the examples and comparative examples for plating. The process conditions were: cathode current density: 1.8ASD, temperature: 25℃, and time: 60min. After plating, the plates were removed, washed with water, and dried.

[0111] After electroplating, each test board is sliced, and the dimple value of the blind vias in each test board is measured. The dimple value reflects the "through-filling ability," which is evaluated by the size of the copper thickness deposited inside the blind via relative to the depression value of the copper layer deposited on the surface of the test board. The closer the dimple value is to 0 in the positive range, the better the through-filling ability of the electroplating solution.

[0112] Deep plating capability: The deep plating capability is characterized by the TP value, that is, TP = average thickness of the hole center excluding the bottom copper thickness / average copper thickness of the plating surface. The closer the ratio is to 100%, the better the deep plating capability of the electroplating solution.

[0113] Surface tension: Tested using a surface tension meter, the lower the surface tension of the electroplating solution, the easier it is for the electroplating solution to penetrate into small gaps and to wet the surface of the object being plated.

[0114] The filling effect of blind vias: The filling effect was observed using metallographic sectioning. A comprehensive score was given based on the post-plating appearance of depressions, bulges, and cracks, with an evaluation grade ranging from A (excellent filling effect) to D (poor filling effect). Experimental data are shown in Table 1.

[0115] Table 1. Experimental data of Examples 1-17 and Comparative Examples 1-9

[0116]

[0117]

[0118] Comparing Example 1 and Comparative Example 1, the dimple value and surface tension in Comparative Example 1 are both greater than those in Example 1; the deep plating capability value in Comparative Example 1 is less than that in Example 1, and the pore effect level is lower than that in Example 1. This indicates that adding a suitable surfactant can improve the permeability of the electroplating solution and improve the electroplating effect.

[0119] Comparing Example 1 and Comparative Examples 2-5, the dimple value and surface tension in Comparative Examples 2-5 are greater than those in Example 1; the deep plating ability value in Comparative Examples 2-5 is less than that in Example 1; and the pore effect level in Comparative Example 1 is lower than that in Example 1. This indicates that by using oleyl alcohol polyoxyethylene carboxylate, hexadecyl pyridine chloride, and sodium cocoyl glutamate in a specific ratio, the permeability of the electroplating solution can be improved, thereby improving the electroplating effect.

[0120] Comparing Example 1 and Comparative Example 6, the dimple value and surface tension in Comparative Example 6 are both greater than those in Example 1; the deep plating capability value in Comparative Example 6 is less than that in Example 1, and the pore effect level is lower than that in Example 1. This indicates that adding a suitable stabilizer can improve the permeability of the electroplating solution and improve the electroplating effect.

[0121] Comparing Example 1 and Comparative Examples 7-8, the dimple value and surface tension in Comparative Examples 7-8 are both greater than those in Example 1; the deep plating capability value in Comparative Examples 7-8 is less than that in Example 1, and the pore effect level is lower than that in Example 1. This indicates that by adding 2-mercaptobenzothia and tin isooctyl dimethyldimercaptoacetate, the permeability of the electroplating solution can be improved, thereby improving the electroplating effect.

[0122] Comparing Examples 1 and 4-5, the dimple value and surface tension in Examples 4-5 are greater than those in Example 1; the deep plating capability value in Examples 4-5 is less than that in Example 1. This indicates that by optimizing the dosage of oleyl alcohol polyoxyethylene carboxylate, hexadecylpyridine chloride and sodium cocoyl glutamate, the permeability of the electroplating solution can be improved, thereby enhancing the electroplating effect.

[0123] Comparing Examples 1 and 6, the dimple value and surface tension in Example 6 are both greater than those in Example 1; the deep plating capacity values ​​in Examples 4 and 5 are less than those in Example 1. This indicates that by optimizing the amount of 2-mercaptobenzothia and dimethyldimercaptoacetic acid isooctyl tin, the permeability of the electroplating solution can be improved, thereby enhancing the electroplating effect.

[0124] Comparing Examples 1 and 7-8, the dimple value and surface tension in Examples 7-8 are both lower than those in Example 1; the deep plating capability in Examples 7-8 is greater than that in Example 1.

[0125] Comparing Examples 7 and 9-10, the dimple value and surface tension in Example 7 are both lower than those in Examples 9-10; the deep plating capability value in Example 7 is greater than that in Examples 9-10.

[0126] Data from Examples 1 and 7-8, 7 and 9-10 show that using dimethylpyrazole, 3-mercaptopropane-1-sulfonic acid, and 2-amino-3-pyridinethiol as leveling agents can improve the permeability of the electroplating solution and enhance the electroplating effect.

[0127] Comparing Example 1 and Example 11, the dimple value and surface tension in Example 11 are both lower than those in Example 1; the deep plating capability value in Example 11 is greater than that in Example 1, and the pore effect level in Example 11 is higher than that in Example 1.

[0128] Comparing Example 7 and Example 12, the dimple value and surface tension in Example 12 are both lower than those in Example 7; the deep plating capability value in Example 12 is greater than that in Example 7.

[0129] Comparing Examples 11 and 13-14, the dimple value and surface tension in Example 11 are both lower than those in Example 13-14; the deep plating capability value in Example 11 is greater than that in Example 13-14, and the pore effect level in Example 11 is higher than that in Example 13-14; it can be seen from Examples 1 and 11, Examples 7 and 12, and Examples 11 and 13-14 that by using sodium polydithiopropane sulfonate, pyridinyl sulfobetaine, and potassium 3-mercapto-1-ethyl sulfonate as brighteners, the permeability of the electroplating solution can be improved, thereby improving the electroplating effect.

[0130] Comparing Example 1 and Example 15, the dimple value and surface tension in Example 15 are both lower than those in Example 1; the deep plating capability value in Example 15 is greater than that in Example 1, and the pore effect level in Example 15 is higher than that in Example 1.

[0131] Comparing Example 12 and Example 16, the dimple value and surface tension in Example 16 are both lower than those in Example 12;

[0132] Comparing Example 15 and Example 17, the dimple value and surface tension in Example 15 are both lower than those in Example 17; and the pore-refining effect of Example 15 is higher than that of Example 17.

[0133] As can be seen from Examples 1 and 15, Examples 12 and 16, and Examples 15 and 17, using hydroxyethylidene diphosphonic acid and tartaric acid as complexing agents can improve the permeability of the electroplating solution and enhance the electroplating effect.

[0134] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An electroplating solution for filling vias in HDI boards, characterized in that, It is prepared from the following raw materials in parts by weight: 120-240 parts copper salt 10-15 parts of complexing agent 5-10 parts of leveling agent 45-70 parts of sulfuric acid stabilizer 10-20 parts 10-20 parts of surfactant 5-10 parts pH adjuster 8-12 parts of brightener 1000 portions of water The stabilizer is composed of 2-mercaptobenzothiazole and isooctyl tin dimethyldimercaptoacetate; The surfactant is composed of oleyl alcohol polyoxyethylene carboxylate, hexadecyl pyridine chloride and sodium cocoyl glutamate; The weight ratio of the oleyl alcohol polyoxyethylene carboxylate, the hexadecyl pyridine chloride, and the sodium cocoyl glutamate is (4-8):(2-4):3; The weight ratio of the 2-mercaptobenzothiazole and the tin isooctyl dimethyldimercaptoacetate is (3-6):

4.

2. The electroplating solution for filling holes in an HDI board according to claim 1, characterized in that: The leveling agent is at least one of dimethylpyrazole, sodium tartrate, 3-mercaptopropane-1-sulfonic acid, 2-amino-3-pyridinethiol, 6-amino-2-naphthylthiol and 3-(dimethylamino)-1-propanethiol.

3. The electroplating solution for filling holes in an HDI board according to claim 1, characterized in that: The leveling agent is composed of dimethylpyrazole, 3-mercaptopropane-1-sulfonic acid and 2-amino-3-pyridinethiol in a weight ratio of (5-8):(2-4):

3.

4. The electroplating solution for filling holes in an HDI board according to claim 1, characterized in that: The copper salt includes at least one of copper sulfate, copper nitrate, copper bromide, copper methanesulfonate, and copper chloride.

5. The electroplating solution for filling holes in an HDI board according to claim 1, characterized in that: The complexing agent is obtained by mixing hydroxyethylidene diphosphonic acid and tartaric acid in a weight ratio of (4-8):

3.

6. The electroplating solution for filling holes in an HDI board according to claim 1, characterized in that: The pH adjuster includes one of phosphoric acid, pyrophosphate, and citric acid.

7. A method for preparing an electroplating solution for filling holes in an HDI board as described in any one of claims 1-6, characterized in that, The preparation steps include the following: The copper salt, complexing agent, leveling agent, sulfuric acid, stabilizer, pH adjuster, surfactant, brightener and water are mixed evenly to obtain the electroplating solution for filling holes in HDI boards.

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