Electroplating solution for HDI plate hole filling and preparation method

Abstract

The invention relates to the technical field of electroplating solution processing, in particular to an electroplating solution for HDI plate hole filling and a preparation method, and the electroplating solution is prepared from the following raw materials in parts by weight: 120-240 parts of copper salt, 10-15 parts of a complexing agent, 5-10 parts of a leveling agent, 45-70 parts of sulfuric acid, 10-20 parts of a stabilizer, 10-20 parts of a surfactant, 5-10 parts of a pH regulator, 8-12 parts of an accelerator, 8-12 parts of a brightener and 1000 parts of water. The stabilizing agent is prepared from 2-mercapto benzothiazide and dimethyl tin isooctyl dimercaptoacetate; the surfactant is prepared from oleyl alcohol polyoxyethylene carboxylate, cetylpyridinium chloride and sodium cocoyl glutamate. The electroplating liquid for filling holes of the HDI board, prepared by adopting a formula, effectively solves the problems of poor permeability, uneven current distribution and the like of blind hole copper filling in the electroplating process of the HDI board, so that the quality and the reliability of a plating layer are remarkably improved.

Description

Technical Field

[0001] The present application relates to the technical field of electroplating solution processing, and more specifically, to an electroplating solution for filling holes in HDI boards and a preparation method thereof. Background Art

[0002] HDI board, or high-density interconnect board, is a circuit board with a relatively high line distribution density that uses micro blind buried hole technology. HDI board has inner and outer layers of lines, and then uses drilling, in-hole metallization and other processes to connect the internal layers of each layer of lines. Among them, the use of blind hole electroplating filling technology is one of the key processes to achieve electrical interconnection between HDI board layers. Blind hole electroplating filling technology can not only ensure the electrical interconnection performance of the blind hole, but also affect the quality and production efficiency of the entire HDI board.

[0003] Compared with traditional multilayer boards, the apertures of through holes and blind holes in HDI boards are much smaller. During the electroplating process, as the blind hole's thickness-to-diameter ratio (i.e., the ratio of the blind hole's depth to its diameter) gradually increases, the difficulty of copper plating in the through and blind holes also increases. The reason is that the smaller the blind hole's aperture, the worse the permeability of the electroplating solution in the hole, and the electroplating solution is difficult to evenly and fully penetrate into every corner of the hole, resulting in insufficient copper plating or uneven plating in some parts of the hole, thereby affecting the quality and reliability of the plating. At the same time, during the electroplating process, the distribution of current in the hole presents a waist drum shape, that is, the current density at the edge of the hole is high and the current density at the center of the hole is low. As the blind hole's thickness-to-diameter ratio increases, the phenomenon of uneven current distribution becomes more obvious. This will cause the coating to be too thick at the edge of the hole, too thin at the center of the hole, or even no coating. Summary of the invention

[0004] In order to improve the problem of poor permeability of the electroplating solution in the hole, the present application provides an electroplating solution for filling holes in an HDI board and a preparation method thereof.

[0005] In a first aspect, the present application provides an electroplating solution for filling holes in HDI boards, which adopts the following technical solution: An electroplating solution for filling holes in HDI boards is prepared from the following raw materials in parts by weight: Copper salt 120-240 parts Complexing agent 10-15 parts Leveling agent 5-10 parts Sulfuric acid 45-70 parts Stabilizer 10-20 parts Surfactant 10-20 parts pH regulator 5-10 parts Accelerator 8-12 parts Brightener 8-12 parts 1000 parts water The stabilizer is composed of 2-mercaptobenzothiol and isooctyltin dimethyldithioacetate; The surfactant is composed of oleyl alcohol polyoxyethylene carboxylate, cetyl pyridinium chloride and sodium cocoyl glutamate.

[0006] By adopting the above technical solution, the problems of poor permeability and uneven current distribution faced by blind hole copper filling in the HDI board electroplating process are effectively solved, thereby significantly improving the quality and reliability of the coating.

[0007] Among them, by mixing oleyl alcohol polyoxyethylene carboxylate, cetyl pyridinium chloride and sodium cocoyl glutamate, the surface tension of the plating solution is effectively reduced, and its penetration ability in the blind hole is enhanced, so that the plating solution can penetrate into every corner of the blind hole more evenly and fully, significantly reducing the risk of insufficient copper plating or uneven plating.

[0008] The addition of leveling agent helps to suppress copper deposition in high current density areas, while brightener can promote the brightness and flatness of the coating. The synergistic effect of leveling agent and brightener helps to alleviate the negative impact of uneven current distribution, that is, the phenomenon of too thick coating at the edge of the hole and too thin coating in the center of the hole, thereby improving the overall uniformity of the coating. The concentration range of copper salt in the formula ensures sufficient copper ion supply to meet the copper plating needs. At the same time, the use of complexing agent effectively stabilizes the morphology of copper ions, prevents their precipitation or agglomeration during the electroplating process, and further improves the uniformity and stability of the coating.

[0009] The stabilizer composed of 2-mercaptobenzothiol and isooctyltin dimethyldithioacetate plays a dual protective role in the electroplating process. On the one hand, it can prevent the oxidation and corrosion of the coating during the electroplating process; on the other hand, it can also stabilize the copper ion concentration in the electroplating solution to avoid the precipitation and agglomeration of copper ions. This dual protective effect ensures the stability and durability of the coating. By adding an appropriate amount of pH regulator, the pH of the electroplating solution can be accurately controlled, thereby ensuring the stability and controllability of the electroplating process.

[0010] Preferably, the weight ratio of the oleyl alcohol polyoxyethylene carboxylate, the cetyl pyridinium chloride and the sodium cocoyl glutamate is (4-8):(2-4):3.

[0011] By adopting the above technical solution, the dosage of oleyl alcohol polyoxyethylene carboxylate, cetylpyridinium chloride and sodium cocoyl glutamate is optimized to further ensure the efficient synergistic effect of surfactants in the electroplating solution, further enhance the penetration performance of the electroplating solution, and enable the electroplating solution to more fully penetrate into the blind hole, thereby improving the uniformity and integrity of copper plating. Secondly, this ratio also helps to optimize the distribution of current in the hole, reduce defects and porosity in the coating, and thus improve the overall quality and reliability of the coating.

[0012] Preferably, the weight ratio of the 2-mercaptobenzothiol and the isooctyltin dimethyldithioacetate is (3-6):4.

[0013] By adopting the above technical scheme, the dosage of 2-mercaptobenzothiol and isooctyl tin dimethyl dimercaptoacetate is optimized, ensuring 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.

[0014] Secondly, this ratio also helps to stabilize the copper ion concentration in the electroplating solution, prevent the precipitation and agglomeration of copper ions, ensure the smooth progress of the electroplating process, and further improve the quality and uniformity of the coating.

[0015] Preferably, the leveling agent is at least one of dimethylpyrazole, sodium tartrate, 3-mercaptopropane-1-sulfonic acid, 2-amino-3-pyridinethiol, 6-amino-2-naphthalenethiol and 3-(dimethylamino)-1-propanethiol.

[0016] By adopting the above technical solution and optimizing the type of leveling agent, the uneven distribution of current in the hole can be significantly improved, so that the coating can be evenly deposited in all parts of the hole, avoiding the situation where the coating is too thick at the edge of the hole and too thin or even no coating in the center of the hole, thereby improving the uniformity and integrity of the coating. At the same time, these leveling agents can also optimize the surface tension of the plating solution, further improve the penetration performance of the plating solution, ensure that the plating solution can fully penetrate into the blind hole, and improve the efficiency and effect of copper plating.

[0017] 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.

[0018] By adopting the above technical solution, it is ensured that the leveling agent can fully play its role in regulating the current distribution, making the current distribution in the hole more uniform during the electroplating process, effectively avoiding the problem of uneven coating thickness, and significantly improving the uniformity and consistency of the coating. At the same time, this combination also enhances the penetration performance of the electroplating solution, allowing the electroplating solution to more fully penetrate into the blind hole, ensuring the efficient copper plating process, and further improving the quality and reliability of the coating.

[0019] Preferably, the copper salt includes at least one of copper sulfate, copper nitrate, copper bromide, copper methanesulfonate and copper chloride.

[0020] By adopting the above technical solution, a rich source of copper ions is provided, ensuring a stable supply of copper ions during the electroplating process, providing a sufficient material basis for the formation of the coating, and helping to optimize the electrochemical properties of the electroplating solution, so that the electroplating solution can adapt to the copper filling needs of blind holes with different aperture sizes and different thickness-to-diameter ratios, thereby improving the electroplating efficiency and coating quality.

[0021] Preferably, the brightener is composed of sodium polydisulfide dipropane sulfonate, pyridinylpropyl sulfobetaine and 3-mercapto-1-ethylsulfonic acid potassium salt in a weight ratio of (4-6): (1-2): 5.

[0022] By adopting the above technical solution, it is ensured that 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 decorativeness and aesthetics of the coating.

[0023] At the same time, this combination also has good wettability and dispersibility, which helps to improve the fluidity and permeability of the electroplating solution, so that the electroplating solution can cover the surface of the substrate more evenly, further improving the uniformity and density of the coating. In addition, this brightener combination also has good stability and compatibility, and can work synergistically with other components in the electroplating solution to jointly improve electroplating efficiency and coating quality.

[0024] Preferably, the complexing agent is obtained by mixing hydroxyethylidene diphosphonic acid and tartaric acid in a weight ratio of (4-8):3.

[0025] By adopting the above technical solution, it is ensured that the complexing agent can effectively complex with copper ions to form a stable complex, thereby preventing the copper ions from hydrolyzing or precipitating during the electroplating process, and ensuring the stability of the electroplating solution and the quality of the coating. At the same time, the synergistic effect of hydroxyethylidene diphosphonic acid and tartaric acid also enhances the buffering capacity of the electroplating solution, helps to adjust the pH value of the electroplating solution to keep it within a suitable range, further improves the stability and controllability of the electroplating process, and helps to improve the uniformity and density of the coating.

[0026] Preferably, the pH adjuster includes one of phosphoric acid, pyrophosphoric acid and citric acid.

[0027] By adopting the above technical solution, the pH value 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 and can form stable complexes with copper ions to prevent copper ions from precipitating during the electroplating process, further improving the stability of the electroplating solution. Secondly, these pH regulators also have a certain buffering effect, which can resist the acid-base changes produced during the electroplating process, maintain the relative stability of the pH value of the electroplating solution, and make the electroplating process more controllable.

[0028] In a second aspect, the present application provides a method for preparing an electroplating solution for filling holes in HDI boards, using the following technical solution: A method for preparing an electroplating solution for filling holes in an HDI board comprises uniformly mixing copper salt, a complexing agent, a leveling agent, sulfuric acid, a stabilizer, a pH regulator, a surfactant, a brightener and water to obtain an electroplating solution for filling holes in an HDI board.

[0029] By adopting the above technical solution, the prepared electroplating solution has excellent hole filling ability and coating quality, and can evenly and efficiently fill the tiny blind holes in the HDI board, ensuring the uniform distribution of the coating inside and outside the hole, avoiding problems such as uneven coating thickness and porosity. At the same time, the electroplating solution also has good stability and operability, and can maintain a stable electroplating effect within a wide range of process parameters, reducing the failure rate and defective product rate during the electroplating process.

[0030] In summary, this application has the following beneficial effects: 1. The present invention prepares a plating solution for HDI board hole filling by using copper salt, complexing agent, leveling agent, sulfuric acid, stabilizer, pH adjuster, surfactant, brightener and water in a specific ratio, which can effectively solve the problems of poor permeability and uneven current distribution in the HDI board hole filling electroplating process, that is, through the carefully designed raw material ratio and combination, the permeability of the plating solution is significantly improved, the current distribution is optimized, and the coating quality and electroplating efficiency are improved. DETAILED DESCRIPTION Example

[0031] Example 1 An electroplating solution for filling holes in HDI boards is prepared by the following method: Mix 120 g of copper salt (copper sulfate), 10 g of complexing agent (hydroxyethylidene diphosphonic acid), 5 g of leveling agent (dimethylpyrazole), 45 g of sulfuric acid, 10 g of stabilizer, 5 g of pH adjuster (phosphoric acid), 10 g of surfactant, 8 g of brightener (sodium polydisulfide dipropane sulfonate) and 1000 g of water to obtain an electroplating solution for filling holes in HDI boards.

[0032] The stabilizer is composed of 2-mercaptobenzothiol and isooctyl tin dimethyldithioacetate in a weight ratio of 3:4.

[0033] The surfactant is composed of oleyl alcohol polyoxyethylene carboxylate, cetyl pyridinium 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.

[0034] Example 2 An electroplating solution for filling holes in HDI boards is prepared by the following method: 180 g of copper salt (copper nitrate), 13 g of complexing agent (sodium potassium tartrate), 8 g of leveling agent (sodium tartrate), 60 g of sulfuric acid, 15 g of stabilizer, 8 g of pH adjuster (pyrophosphoric acid), surfactant, 10 g of brightener (pyridinylpropyl sulfobetaine) and 1000 g of water were mixed evenly to obtain an electroplating solution for filling holes in HDI boards.

[0035] The stabilizer is composed of 2-mercaptobenzothiol and isooctyl tin dimethyldithioacetate in a weight ratio of 5:4.

[0036] The surfactant is composed of oleyl alcohol polyoxyethylene carboxylate, cetyl pyridinium chloride and sodium cocoyl glutamate in a weight ratio of 6:3:3.

[0037] Example 3 An electroplating solution for filling holes in HDI boards is prepared by the following method: 240 g of copper salt (copper bromide), 15 g of complexing agent (diethylenetriamine pentaacetic acid), 10 g of leveling agent (2-amino-3-pyridinethiol), 70 g of sulfuric acid, 20 g of stabilizer, 10 g of pH adjuster (citric acid), 20 g of surfactant, 12 g of brightener (potassium salt of 3-mercapto-1-ethylsulfonic acid) and 1000 g of water were mixed evenly to obtain an electroplating solution for filling holes in HDI boards.

[0038] The stabilizer is composed of 2-mercaptobenzothiol and isooctyltin dimethyldithioacetate in a weight ratio of 6:4.

[0039] The surfactant is composed of oleyl alcohol polyoxyethylene carboxylate, cetyl pyridinium chloride and sodium cocoyl glutamate in a weight ratio of 8:4:3.

[0040] Example 4 A plating solution for filling holes in HDI boards. The difference between this embodiment and embodiment 1 is that the weight ratio of oleyl alcohol polyoxyethylene carboxylate, cetyl pyridinium chloride and sodium cocoyl glutamate is 2:2:3.

[0041] Example 5 A plating solution for filling holes in HDI boards. The difference between this embodiment and embodiment 1 is that the weight ratio of oleyl alcohol polyoxyethylene carboxylate, cetyl pyridinium chloride and sodium cocoyl glutamate is 4:2:4.

[0042] Example 6 A plating solution for filling holes in HDI boards. The difference between this embodiment and embodiment 1 is that the weight ratio of 2-mercaptobenzothiol and dimethyldithioacetate isooctyltin is 3:3. (The amount of dimethyldithioacetate isooctyltin is reduced) Example 7 A plating solution for filling holes in HDI boards. The difference between this embodiment and embodiment 1 is that the leveler is composed of dimethylpyrazole, 3-mercaptopropane-1-sulfonic acid and 2-amino-3-pyridinethiol in a weight ratio of 8:2:3.

[0043] Example 8 A plating solution for filling holes in HDI boards. The difference between this embodiment and embodiment 1 is that the leveler is composed of dimethylpyrazole, 3-mercaptopropane-1-sulfonic acid and 2-amino-3-pyridinethiol in a weight ratio of 8:4:3.

[0044] Example 9 A plating solution for filling holes in HDI boards. The difference between this embodiment and embodiment 7 is that the leveler is composed of dimethylpyrazole and 3-mercaptopropane-1-sulfonic acid in a weight ratio of 8:4.

[0045] Example 10 A plating solution for filling holes in HDI boards. The difference between this embodiment and embodiment 7 is that the leveler is composed of dimethylpyrazole and 2-amino-3-pyridinethiol in a weight ratio of 8:3.

[0046] Embodiment 11 A plating solution for filling holes in HDI boards. The difference between this embodiment and embodiment 1 is that the brightener is composed of sodium polydipropane disulfide sulfonate, pyridinylpropyl sulfobetaine and 3-mercapto-1-ethylsulfonic acid potassium salt in a weight ratio of 4:1:5.

[0047] Example 12 A plating solution for filling holes in HDI boards. The difference between this embodiment and embodiment 7 is that the brightener is composed of sodium polydipropane disulfide sulfonate, pyridinylpropyl sulfobetaine and 3-mercapto-1-ethylsulfonic acid potassium salt in a weight ratio of 6:2:5.

[0048] Embodiment 13 A plating solution for filling holes in HDI boards. The difference between this embodiment and embodiment 11 is that the brightener is composed of sodium polydipropylene sulfonate and pyridinylpropyl sulfobetaine in a weight ratio of 6:2.

[0049] Embodiment 14 A plating solution for filling holes in HDI boards. The difference between this embodiment and embodiment 11 is that the brightener is composed of sodium polydipropane disulfide sulfonate and potassium 3-mercapto-1-ethylsulfonate in a weight ratio of 6:5.

[0050] Embodiment 15 A plating solution for filling holes in HDI boards. The difference between this embodiment and embodiment 1 is that the complexing agent is obtained by mixing hydroxyethylidene diphosphonic acid and tartaric acid in a weight ratio of 4:3.

[0051] Example 16 A plating solution for filling holes in HDI boards. The difference between this embodiment and embodiment 12 is that the complexing agent is obtained by mixing hydroxyethylidene diphosphonic acid and tartaric acid in a weight ratio of 8:3.

[0052] Embodiment 17 A plating 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.

[0053] Comparative Example Comparative Example 1 A plating solution for filling holes in HDI boards. The difference between this comparative example and Example 1 is that no surfactant is added.

[0054] Comparative Example 2 A plating 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 cetylpyridinium chloride in a weight ratio of 4:2.

[0055] Comparative Example 3 A plating 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.

[0056] Comparative Example 4 A plating solution for filling holes in HDI boards. The difference between this comparative example and Example 1 is that the surfactant is composed of cetylpyridinium chloride and sodium cocoyl glutamate in a weight ratio of 2:3.

[0057] Comparative Example 5 A plating 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.

[0058] Comparative Example 6 A plating solution for filling holes in HDI boards. The difference between this comparative example and Example 1 is that no stabilizer is added.

[0059] Comparative Example 7 A plating solution for filling holes in HDI boards. The difference between this comparative example and Example 1 is that the stabilizer is 2-mercaptobenzothiol.

[0060] Comparative Example 8 A plating solution for filling holes in HDI boards. The difference between this comparative example and Example 1 is that the stabilizer is isooctyl tin dimethyl dimercaptoacetate.

[0061] Comparative Example 9 A plating solution for filling holes in HDI boards. The difference between this comparative example and Example 1 is that no pH regulator is added.

[0062] Detection method / test method Take a test board with blind holes of the same size (taking 125×75μm (wherein the hole diameter is 125μm) as an example) and place it in the electroplating solution provided in the embodiment and the comparative example for plating. The process conditions are: cathode current density: 1.8ASD, adaptation temperature 25°C, time 60min. Take it out, wash it with water, and dry it.

[0063] After the electroplating is completed, each test board is sliced ​​and the dimple value of the blind hole in each test board is measured. The dimple value reflects the "hole filling ability", that is, the thickness of the copper deposited in the blind hole is evaluated 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 hole filling ability of the electroplating solution.

[0064] Throwing ability: The TP value is used to characterize the throwing ability, that is, TP = average thickness in the middle of the hole excluding the bottom copper thickness / average plated copper thickness. The closer the ratio is to 100%, the better the throwing ability of the electroplating solution.

[0065] Surface tension: Use a surface tension meter to test. The smaller the surface tension of the plating solution, the easier it is for the plating solution to penetrate into small gaps and wet the surface of the object being plated.

[0066] Blind hole filling effect: The filling effect is observed by metallographic sectioning, and the depression, bulge, cracks and other phenomena after the hole filling plating are comprehensively scored. The evaluation level is A (excellent filling effect)-D (poor filling effect). The experimental data is shown in Table 1: Table 1 Experimental data of Examples 1-17 and Comparative Examples 1-9 Comparing Example 1 with Comparative Example 1, the dimple value and surface tension in Comparative Example 1 are greater than those in Example 1; the deep plating ability value in Comparative Example 1 is less than that in Example 1, and the level of the pore effect is lower than that in Example 1, indicating that adding a suitable surfactant can improve the permeability of the plating solution and improve the electroplating effect.

[0067] By comparing Example 1 with Comparative Examples 2-5, the dimple value and the surface tension in Comparative Examples 2-5 are greater than those in Example 1; the deep plating ability values ​​in Comparative Examples 2-5 are less than those in Example 1; and the level of the pore effect in Comparative Example 1 is lower than that in Example 1, indicating that by using oleyl alcohol polyoxyethylene carboxylate, cetylpyridinium chloride and sodium cocoyl glutamate in a specific proportion, the permeability of the plating solution can be improved and the electroplating effect can be improved.

[0068] Comparing Example 1 with Comparative Example 6, the dimple value and surface tension in Comparative Example 6 are greater than those in Example 1; the deep plating ability value in Comparative Example 6 is less than that in Example 1, and the level of the pore effect is lower than that in Example 1, indicating that adding a suitable stabilizer can improve the permeability of the plating solution and improve the electroplating effect.

[0069] Comparing Example 1 with Comparative Examples 7-8, the dimple value and surface tension in Comparative Examples 7-8 are greater than those in Example 1; the deep plating ability value in Comparative Examples 7-8 is less than that in Example 1, and the level of the pore effect is lower than that in Example 1, indicating that the addition of 2-mercaptobenzothiol and isooctyltin dimethyldithioacetate can improve the permeability of the electroplating solution and improve the electroplating effect.

[0070] Comparing Example 1 with Example 4-5, the dimple value and surface tension in Example 4-5 are both greater than those in Example 1; the deep plating ability value in Example 4-5 is less than that in Example 1, indicating that by optimizing the dosage of oleyl alcohol polyoxyethylene carboxylate, cetylpyridinium chloride and sodium cocoyl glutamate, the permeability of the plating solution can be improved and the electroplating effect can be improved.

[0071] Comparing Example 1 with Example 6, the dimple value and surface tension in Example 6 are both greater than those in Example 1; the deep plating ability values ​​in Examples 4-5 are less than those in Example 1, indicating that by optimizing the dosage of 2-mercaptobenzothiol and isooctyltin dimethyldithioacetate, the permeability of the electroplating solution can be improved and the electroplating effect can be improved.

[0072] By comparing Example 1 with Example 7-8, the dimple value and surface tension in Example 7-8 are both smaller than those in Example 1; the deep plating ability value in Example 7-8 is greater than that in Example 1; Comparing Example 7 with Examples 9-10, the dimple value and surface tension in Example 7 are both smaller than those in Examples 9-10; and the deep plating ability value in Example 7 is greater than those in Examples 9-10.

[0073] From the data of Examples 1 and 7-8, 7 and 9-10, it can be seen that by using dimethylpyrazole, 3-mercaptopropane-1-sulfonic acid and 2-amino-3-pyridinethiol as leveling agents, the permeability of the plating solution can be improved and the electroplating effect can be improved.

[0074] By comparing Example 1 with Example 11, the dimple value and surface tension in Example 11 are both smaller than those in Example 1; the deep plating ability value in Example 11 is greater than that in Example 1, and the level of the pore effect in Example 11 is higher than that in Example 1; By comparing Example 7 with Example 12, the dimple value and surface tension in Example 12 are both smaller than those in Example 7; the deep plating ability value in Example 12 is larger than that in Example 7; Comparing Example 11 with Example 13-14, the dimple value and surface tension in Example 11 are both smaller than those in Example 13-14; the deep plating ability value in Example 11 is greater than that in Example 13-14, and the level of the pore effect 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 polydisulfide dipropane sulfonate, pyridinylpropyl sulfobetaine and potassium 3-mercapto-1-ethylsulfonate as brighteners, the permeability of the plating solution can be improved and the plating effect can be improved.

[0075] By comparing Example 1 with Example 15, the dimple value and surface tension in Example 15 are both smaller than those in Example 1; the deep plating ability value in Example 15 is greater than that in Example 1, and the level of the pore effect in Example 15 is higher than that in Example 1; Comparing Example 12 with Example 16, the dimple value and surface tension in Example 16 are both smaller than those in Example 12; By comparing Example 15 with Example 17, the dimple value and surface tension in Example 15 are both smaller than those in Example 17; and the level of the pore effect in Example 15 is higher than that in Example 17; It can be seen from Examples 1 and 15, Examples 12 and 16, and Examples 15 and 17 that the use of hydroxyethylidene diphosphonic acid and tartaric acid as complexing agents can improve the permeability of the electroplating solution and improve the electroplating effect.

[0076] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A plating solution for filling holes in HDI boards, characterized in that: Prepared from the following raw materials in parts by weight: Copper salt 120-240 parts Complexing agent 10-15 parts Leveling agent 5-10 parts Sulfuric acid 45-70 parts Stabilizer 10-20 parts Surfactant 10-20 parts pH regulator 5-10 parts Brightener 8-12 parts 1000 parts water The stabilizer is composed of 2-mercaptobenzothiol and isooctyltin dimethyldithioacetate; The surfactant is composed of oleyl alcohol polyoxyethylene carboxylate, cetyl pyridinium chloride and sodium cocoyl glutamate.

2. The electroplating solution for filling holes in HDI boards according to claim 1, characterized in that: The weight ratio of the oleyl alcohol polyoxyethylene carboxylate, the cetyl pyridinium chloride and the sodium cocoyl glutamate is (4-8):(2-4):

3.

3. The electroplating solution for HDI board hole filling according to claim 2, characterized in that: The weight ratio of the 2-mercaptobenzothiol and the dimethyldithioacetic acid isooctyltin is (3-6):

4.

4. The electroplating solution for HDI board hole filling 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-naphthalenethiol and 3-(dimethylamino)-1-propanethiol.

5. The electroplating solution for filling holes in HDI boards according to claim 4, 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.

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

7. The electroplating solution for filling holes in HDI boards according to claim 1, characterized in that: The brightener is composed of sodium polydisulfide dipropane sulfonate, pyridinylpropyl sulfobetaine and 3-mercapto-1-ethylsulfonic acid potassium salt in a weight ratio of (4-6): (1-2):

5.

8. The electroplating solution for filling holes in HDI boards 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.

9. The electroplating solution for filling holes in HDI boards according to claim 1, characterized in that: The pH adjuster includes one of phosphoric acid, pyrophosphoric acid and citric acid.

10. A method for preparing an electroplating solution for filling holes in HDI boards according to any one of claims 1 to 9, characterized in that: The method comprises the following preparation steps: The copper salt, the complexing agent, the leveling agent, the sulfuric acid, the stabilizer, the pH adjusting agent, the surfactant, the brightener and the water are uniformly mixed to obtain the electroplating solution for filling the holes of the HDI board.

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