Substituent group modified phenazine leveling agent, acid copper plating solution and preparation method and application of acid copper plating solution

Abstract

The invention discloses a substituent-modified phenazine leveling agent, an acid copper plating solution and a preparation method and application thereof, chlorine atoms are introduced to a specific position of phenazine for modification, so that the acid copper plating solution containing the leveling agent has a high pore filling rate while obtaining a high-brightness plating layer, and the pore filling capacity of the leveling agent at a low concentration is effectively improved; and resource saving and cost reduction are facilitated. The total synthesis of the chlorine atom modified phenazine leveling agent is realized by using a chlorine-substituted raw material, and no complex reaction process and harsh reaction conditions exist, so that the method has industrial value.

Description

Technical Field

[0001] This invention belongs to the field of PCB electroplating materials technology, specifically relating to a substituent-modified phenazine leveling agent, an acid copper plating solution, its preparation method, and its application. Background Technology

[0002] Microvia copper plating, as an important metallization technology, is widely used in advanced packaging and printed circuit board (PCB) interconnect manufacturing. Currently, the acidic electrolyte mainly used in the microvia copper plating industry consists of copper sulfate, sulfuric acid, chloride ions, and trace amounts of organic additives. During the microvia filling process, due to uneven current density distribution and uneven mass transfer inside and outside the via, the rate of copper deposition inside the microvia is slower than at the via opening, causing premature closure at the microvia opening and resulting in gaps or voids inside the microvia. Organic additives in the electrolyte can regulate the copper deposition rate inside and outside the via, accelerating copper deposition inside the via and inhibiting copper deposition at the via opening and surface. This filling mode is called "superconformal" or "bottom-up" copper plating, ensuring void-free microvia filling and effectively improving the reliability and stability of PCB electrical interconnects. Therefore, organic additives play a crucial role in achieving defect-free microvia copper plating.

[0003] Leveling agents, as key components of copper plating additives, play a crucial role in the electroplating process. Highly efficient and practical leveling agents are sought after in PCB copper plating. An ideal leveling agent typically possesses a high fill factor (FP). Traditional leveling agent additives are often used in decorative electroplating to achieve high-gloss coatings, but their fill factor is usually poor. For example, Henry Brown et al. reported on phenazine-based leveling agents for bright copper plating; while the resulting coating was bright, their fill factor was not disclosed. Summary of the Invention

[0004] For the reasons mentioned above, the first objective of this invention is to provide a substituent-modified phenazine leveling agent, wherein the azo group linkage site on the phenazine group is modified with a chlorine atom at the adjacent position, thereby changing the frontier orbital energy level of the molecule, improving its adsorption capacity on the copper matrix, and thus improving the pore-filling performance of the leveling agent.

[0005] The second objective of this invention is to provide a method for preparing a substituent-modified phenazine leveling agent, and to design a total synthesis of a chlorine-substituted phenazine leveling agent, which has industrial value.

[0006] The third objective of this application is to provide the application of substituent-modified phenazine leveling agents as leveling agents in copper plating of PCBs.

[0007] The fourth objective of this application is to provide an acid copper plating solution in which a phenazine leveling agent modified with a substituent can achieve a high gloss coating while also having a high pore filling rate.

[0008] The first objective of this invention can be achieved by adopting the following technical solution:

[0009] A substituent-modified phenazine leveling agent having the molecular structure shown in Formula I:

[0010] .

[0011] The second objective of this invention can be achieved by adopting the following technical solution:

[0012] The substituent-modified phenazine leveling agent is prepared via the following route:

[0013] .

[0014] Further, in step S1, 2-chloroaniline and N,N-dimethyl-p-phenylenediamine dihydrochloride were oxidized with dichromate to prepare compound 1;

[0015] In step S2, compound 1 and aniline were reacted with sodium acetate to prepare compound 2.

[0016] In step S3, after compound 2 reacts with sodium nitrite, it continues to react with N,N-dimethylaniline to prepare the compound with the structure shown in Formula I.

[0017] Further, in step S1, 2-chloroaniline and N,N-dimethyl-p-phenylenediamine dihydrochloride are dissolved in water, and potassium dichromate aqueous solution is added to carry out the reaction;

[0018] The molar ratio of 2-chloroaniline, N,N-dimethyl-p-phenylenediamine dihydrochloride to potassium dichromate is 1:(1-1.2):(1.5-2.5).

[0019] The reaction temperature is 4℃~40℃, and the reaction time is 1~2h.

[0020] Furthermore, in step S2, compound 1 and aniline react in an aqueous solvent;

[0021] The molar ratio of compound 1 to aniline is 1:(1–1.2); the pH is adjusted to 5–6 using sodium acetate;

[0022] The reaction temperature is 90–100℃, and the reaction time is 5–10 h.

[0023] Further, in step S3, compound 2 reacts with sodium nitrite in hydrochloric acid solution to generate a diazonium salt; it then reacts with N,N-dimethylaniline to prepare the compound with the structure shown in Formula I.

[0024] The molar ratio of compound 2, sodium nitrite, and N,N-dimethylaniline is 1:(1-1.2):(1-1.2).

[0025] Add hydrochloric acid at a concentration of 10 to 15 times that of 2 moles of the compound;

[0026] The reaction temperature was 0–5℃, and the time for the formation of diazonium salt was 0.5–2 h; the time for the formation of compound 2 was 2–5 h.

[0027] The third objective of this invention can be achieved by adopting the following technical solution:

[0028] Application of substituent-modified phenazine leveling agents as leveling agents in PCB electroplating copper plating.

[0029] The fourth objective of this invention can be achieved by adopting the following technical solution:

[0030] An acid copper plating solution comprising the substituent-modified phenazine leveling agent.

[0031] Furthermore, the acid copper plating solution includes copper sulfate or its hydrate, sulfuric acid, chloride ions, and the substituent-modified phenazine leveling agent.

[0032] Furthermore, it includes components with the following mass concentrations:

[0033] 180~220g / L CuSO4·5H2O, 40~60g / L H2SO4, 50~70mg / L Cl - And the substituent-modified phenazine leveling agent described in 5–20 mg / L.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] 1. The substituent-modified phenazine leveling agent of this application, by introducing chlorine atoms to modify the phenazine leveling agent, changes the frontier orbital energy level of the molecule and its adsorption capacity on the copper substrate. While obtaining a high-gloss coating, it also has a high pore-filling rate. The pore-filling ability of the leveling agent is effectively improved, which is conducive to saving resources and reducing costs.

[0036] 2. The preparation method of the substituent-modified phenazine leveling agent of this application is designed to achieve the total synthesis of chlorine-atom-modified phenazine leveling agent using chlorine-substituted raw materials. It does not involve a complicated reaction process or harsh reaction conditions and has industrial value.

[0037] 3. The acid copper plating solution of this application contains the above-mentioned substituent-modified phenazine leveling agent. Through chlorine atom modification, the phenazine leveling agent can achieve a high filling rate of PCB blind vias at a low concentration, saving resources and reducing costs. Attached Figure Description

[0038] Figure 1 Here is a high-resolution mass spectrum of the leveling agent PD-Cl prepared in Example 1;

[0039] Figure 2 High-resolution mass spectrum of the leveling agent PD prepared in Comparative Example 1;

[0040] Figure 3 High-resolution mass spectrum of the leveling agent PD-CH3 prepared in Comparative Example 2;

[0041] Figure 4 Schematic diagram of the electroplating hole-filling experimental setup;

[0042] Figure 5 Metallographic images of electroplating pore-filling test of leveling agent PD, a1-f1 represent different concentrations of PD;

[0043] Figure 6 Metallographic images of PD-CH3 electroplating pore-filling test for leveling agent, a2-f2 represent different concentrations of PD-CH3;

[0044] Figure 7 Metallographic images of PD-Cl electroplating pore-filling test, a3-f3 represent PD-Cl at different concentrations;

[0045] Figure 8 The figures are cyclic voltammetric stripping test results; (a) represents PD; (b) represents PD-CH3; (c) represents PD-Cl; and (d) is a comparison of the stripping peak area changes.

[0046] Figure 9 SEM images of electroplated PD-Cl samples: (a) base plating solution; (b) without leveling agent; (c) 1 mg / L PD-Cl; (d) 5 mg / L PD-Cl; (e) 10 mg / L PD-Cl; (f) 20 mg / L PD-Cl; (g) 30 mg / L PD-Cl; (h) 40 mg / L PD-Cl. Detailed Implementation

[0047] The technical solution of the present invention will now be clearly and completely described with reference to specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0048] Existing leveling agents have poor via-filling capabilities, leading to potential quality problems in PCB manufacturing. Therefore, this application provides a substituent-modified phenazine leveling agent, an acid copper plating solution, its preparation method, and its application, which improves its adsorption capacity on copper substrates, thereby enhancing the via-filling performance of the leveling agent. Furthermore, it achieves better PCB blind via filling effects within a lower concentration range, saving resources and reducing costs.

[0049] This application provides a substituent-modified phenazine leveling agent having the molecular structure shown in Formula I:

[0050] .

[0051] The phenazine leveling agent modified by the substituents in this application has a chlorine atom substituted at the ortho position of the azo linkage site in the phenazine structure. Compared with unsubstituted or alkyl-substituted, the chlorine atom substitution changes the frontier orbital energy level of the leveling agent molecule and its adsorption capacity on the copper substrate. When copper plating is performed on PCBs, it not only obtains a high-gloss coating but also has a high hole-filling rate, and the hole-filling ability of the leveling agent is effectively improved.

[0052] This application provides a method for preparing a substituent-modified phenazine leveling agent, which is obtained through the following pathway:

[0053] .

[0054] As one embodiment, in step S1, 2-chloroaniline and N,N-dimethyl-p-phenylenediamine dihydrochloride are oxidized by dichromate to prepare compound 1;

[0055] In step S2, compound 1 and aniline were reacted with sodium acetate to prepare compound 2.

[0056] In step S3, after compound 2 reacts with sodium nitrite, it continues to react with N,N-dimethylaniline to prepare the compound with the structure shown in Formula I.

[0057] Starting with chloroaniline, a three-step total synthesis of phenazine leveling agents with substituents of the structure shown in Formula I was carried out. The raw materials used are readily available, and the reaction conditions are mild and undemanding, providing a simple and efficient synthetic route for substituent-modified phenazine leveling agents.

[0058] In one embodiment, in step S1, 2-chloroaniline and N,N-dimethyl-p-phenylenediamine dihydrochloride are dissolved in water, and potassium dichromate aqueous solution is added to react.

[0059] In this embodiment, 2-chloroaniline and p-phenylenediamine dihydrochloride are dissolved in water to form solutions of 5–50 mmol / L, and then an aqueous solution of potassium dichromate, an oxidizing agent, is added to initiate the reaction. Preferably, the aqueous solution of potassium dichromate is added dropwise. The concentration of the potassium dichromate aqueous solution is 0.1 mmol / ml to 0.5 mmol / ml.

[0060] In one embodiment, the molar ratio of 2-chloroaniline, N,N-dimethyl-p-phenylenediamine dihydrochloride to potassium dichromate is 1:(1-1.2):(1.5-2.5).

[0061] In one embodiment, the reaction temperature is 4℃~40℃, and the reaction time is 1~2h. The reaction time is the time taken after the potassium dichromate solution is added.

[0062] As one implementation method, a post-processing step is also included after the reaction. The reaction solution is filtered, the filter cake is washed with water, and dried to obtain compound 1, which can be directly used in subsequent reactions.

[0063] In one embodiment, in step S2, compound 1 and aniline react in an aqueous solvent; the pH is adjusted to 5-6 using sodium acetate. The molar ratio of compound 1 to aniline is 1:(1-1.2); the molar concentration of compound 1 and aniline is 4-10 mmol / L.

[0064] In one implementation method, the reaction temperature is 90–100°C and the reaction time is 5–10 hours.

[0065] As one embodiment, a post-processing step is also included after the reaction. The reaction solution is filtered while hot, the filtrate is collected, and the filtrate is rotary evaporated to dryness to obtain crude product compound 2. Further, the crude product is purified by column chromatography to obtain the corresponding substituent compound 2.

[0066] In one embodiment, in step S3, compound 2 reacts with sodium nitrite in hydrochloric acid solution to generate a diazonium salt; it then reacts with N,N-dimethylaniline to prepare the compound with the structure shown in Formula I.

[0067] In this embodiment, the reaction temperature between compound 2 and sodium nitrite is 0–5°C; preferably, the reaction is carried out in an ice bath. Sodium nitrite is added dropwise to the hydrochloric acid solution of compound 2.

[0068] In one embodiment, hydrochloric acid is added at 10 to 15 times the molar amount of compound 2. The molar volume ratio of compound 1 to water is 1 mmol: (10 to 50) ml.

[0069] In one implementation method, the diazonium salt is generated in 0.5 to 2 hours.

[0070] In one embodiment, the molar ratio of compound 2, sodium nitrite and N,N-dimethylaniline is 1:(1-1.2):(1-1.2).

[0071] The reaction temperature is 0–5℃, and the time for the formation of compound 2 is 2–5 h.

[0072] As one implementation method, a post-processing step is also included after the reaction. The reaction solution is concentrated and then filtered by salting out to obtain a crude product. The product is then purified by column chromatography to obtain a compound with the structure shown in Formula I.

[0073] This application also provides an acid copper plating solution, including the substituent-modified phenazine leveling agent.

[0074] As one embodiment, the acid copper plating solution includes copper sulfate or its hydrate, sulfuric acid, chloride ions, and the substituent-modified phenazine leveling agent.

[0075] As one embodiment, the components include the following mass concentrations:

[0076] 180~220g / L CuSO4·5H2O, 40~60g / L H2SO4, 50~70mg / L Cl - And the substituent-modified phenazine leveling agent described in 5–20 mg / L.

[0077] As one embodiment, the acid copper plating solution further includes the following components at varying mass concentrations as additives:

[0078] 2-3 mg / L of the accelerator SPS and / or 150-250 mg / L of the inhibitor PEG.

[0079] The following specific examples will provide further details. Example 1

[0080] Synthesis of Compound 1

[0081] 5 mmol of 2-chloroaniline (Aladdin) and 5 mmol of p-phenylenediamine dihydrochloride (Aladdin) were dissolved in 500 mL of water. 90 mL of an aqueous solution containing 10 mmol of potassium dichromate was slowly added dropwise at room temperature. After the addition was complete, the reaction was continued for 2 h. The reaction solution was then filtered to obtain a filter cake, which was washed with a large amount of water and dried to obtain compound 1.

[0082] Synthesis of Compound 2

[0083] Add 4 mmol of compound 1, 700 mL of water and 4 mmol of aniline (Aladdin) to a 1000 mL Erlenmeyer flask. Adjust the pH to 5-6 using sodium acetate (Maclean). Heat the reaction solution to 100 °C and react for 8 h. After the reaction is complete, filter while hot and evaporate the filtrate to dryness to obtain the crude product. The crude product is purified by column chromatography to obtain compound 2.

[0084] Synthesis of compounds with Formula I structure

[0085] Weigh 1 mmol of compound 2 into a 100 mL beaker, add 1 mL of 37% HCl and 20 mL of water to dissolve it. Stir under ice bath conditions to lower the reaction solution temperature to 4 °C. Then, slowly add 5 mL of an aqueous solution containing 1.1 mmol of NaNO2 dropwise. After the addition is complete, keep the reaction at this temperature for 1 h to generate the diazonium salt. Adjust the pH of the reaction solution to 4–6, add 1 mmol of N,N-dimethylaniline (Aladdin), and continue the reaction at 0–5 °C for 3 h. After the reaction is complete, concentrate the reaction solution, salt it out, and filter to obtain the crude product. Purify the product using column chromatography to obtain the compound with structure I, named PD-Cl; the mass spectrum is shown below. Figure 1 As shown. Example 2

[0086] Synthesis of Compound 1

[0087] 5 mmol of 2-chloroaniline (Aladdin) and 5.5 mmol of p-phenylenediamine dihydrochloride (Aladdin) were dissolved in 500 mL of water. 90 mL of an aqueous solution containing 7.5 mmol of potassium dichromate was slowly added dropwise at room temperature. After the addition was complete, the reaction was continued for 1 h. The reaction solution was then filtered to obtain a filter cake, which was washed with a large amount of water and dried to obtain compound 1.

[0088] Synthesis of Compound 2

[0089] 4 mmol of compound 1, 700 mL of water and 4.4 mmol of aniline (Aladdin) were added to a 1000 mL Erlenmeyer flask. The pH was adjusted to 5-6 using sodium acetate (Maclean). The reaction solution was heated to 90 °C and reacted for 10 h. After the reaction was completed, the mixture was filtered while hot. The filtrate was rotary evaporated to dryness to obtain the crude product. The crude product was purified by column chromatography to obtain compound 2.

[0090] Synthesis of compounds with Formula I structure

[0091] Weigh 1 mmol of compound 2 into a 100 mL beaker, add 1 mL of 37% HCl and 20 mL of water to dissolve it, and stir under ice bath conditions to lower the temperature of the reaction solution to 4 °C. Then, slowly add 5 mL of an aqueous solution containing 1 mmol of NaNO2 to the reaction solution. After the addition is complete, keep the reaction at the temperature for 2 h to generate diazonium salt. Adjust the pH of the reaction solution to 4-6, add 1.2 mmol of N,N-dimethylaniline (Aladdin), and continue the reaction at 0-5 °C for 2 h. After the reaction is completed, concentrate the reaction solution and filter it by salting out to obtain the crude product. Purify the product by column chromatography to obtain the compound with structure I. Example 3

[0092] Synthesis of Compound 1

[0093] 5 mmol of 2-chloroaniline (Aladdin) and 6 mmol of p-phenylenediamine dihydrochloride (Aladdin) were dissolved in 500 mL of water. 90 mL of an aqueous solution containing 12.5 mmol of potassium dichromate was slowly added dropwise at room temperature. After the addition was complete, the reaction was continued for 1.5 h. The reaction solution was then filtered to obtain a filter cake, which was washed with a large amount of water and dried to obtain compound 1.

[0094] Synthesis of Compound 2

[0095] 4 mmol of compound 1, 700 mL of water and 4.8 mmol of aniline (Aladdin) were added to a 1000 mL Erlenmeyer flask. The pH was adjusted to 5-6 using sodium acetate (Maclean). The reaction solution was heated to 95 °C and reacted for 5 h. After the reaction was completed, the mixture was filtered while hot. The filtrate was rotary evaporated to dryness to obtain the crude product. The crude product was purified by column chromatography to obtain compound 2.

[0096] Synthesis of compounds with Formula I structure

[0097] Weigh 1 mmol of compound 2 into a 100 mL beaker, add 1 mL of 37% HCl and 20 mL of water to dissolve it, and stir under ice bath conditions to lower the temperature of the reaction solution to 4 °C. Then, slowly add 5 mL of an aqueous solution containing 1.2 mmol of NaNO2 to the reaction solution. After the addition is complete, keep the reaction at the temperature for 0.5 h to generate diazonium salt. Adjust the pH of the reaction solution to 4-6, add 1.1 mmol of N,N-dimethylaniline (Aladdin), and continue the reaction at 0-5 °C for 5 h. After the reaction is completed, concentrate the reaction solution and filter it by salting out to obtain the crude product. Purify the product by column chromatography to obtain the compound with structure I. Example 4

[0098] The acid copper plating solution is 200 g / L CuSO4•5H2O, 50 g / L H2SO4, and 60 mg / L Cl. - 5 mg / ml of a compound with structure I, 4 mg / L of the accelerator SPS, and 200 mg / L of the inhibitor PEG. Example 5

[0099] The acid copper plating solution is 200 g / L CuSO4•5H2O, 50 g / L H2SO4, and 60 mg / L Cl. - 10 mg / ml of a compound of structure I, 4 mg / L of the accelerator SPS and 200 mg / L of the inhibitor PEG. Example 6

[0100] The acid copper plating solution is 200 g / L CuSO4•5H2O, 50 g / L H2SO4, and 60 mg / L Cl. - 20 mg / ml of a compound of structure I, 4 mg / L of the accelerator SPS and 200 mg / L of the inhibitor PEG.

[0101] Comparative Example 1

[0102] The difference between Comparative Example 1 and Example 1 is that aniline was used as a starting material in the synthesis of Compound 1 to prepare the structural leveling agent shown in Formula II, named PD; the mass spectrum is shown below. Figure 2 As shown;

[0103] .

[0104] Comparative Example 2

[0105] The difference between Comparative Example 2 and Example 1 is that 2-methylaniline was used as a starting material in the synthesis of Compound 1 to prepare a structural leveling agent as shown in Formula III, named PD-CH3; the mass spectrum is shown below. Figure 3 As shown;

[0106] .

[0107] (1) Copper plating experiment:

[0108] like Figure 4 The schematic diagram of the plated hole-filling experimental setup is shown. Assemble the electroplating apparatus; the acid copper base plating solution consists of 200 g / L CuSO4•5H2O, 50 g / L H2SO4, and 60 mg / L Cl... - The test conditions were a current density of 1.8 ASD and an electroplating time of 40 min, with a two-way stirring method of 1000 rpm, and additives including 4 mg / L of accelerator SPS, 200 mg / L of inhibitor PEG, and different concentrations of leveling agent.

[0109] The micropore filling rate of electroplating can be calculated by (H3−H2) / H3×100%; where H3 is the hole depth before electroplating and H2 is the hole depth after electroplating.

[0110] PD-Cl prepared in Example 1, PD prepared in Comparative Example 1, and PD-CH3 prepared in Comparative Example 2 were added to the acid copper plating solution at concentrations of 1 mg / L, 5 mg / L, 10 mg / L, 20 mg / L, 30 mg / L, and 40 mg / L, respectively. After electroplating, the metallographic images of the plating layers with different concentrations and additives were observed using a metallographic microscope. The metallographic images are shown below. Figures 5-7 As shown; where Figure 5 In the diagram, a1-f1 represent different concentrations of PD; Figure 6 a2-f2 represent different concentrations of PD-CH3; Figure 7 a3-f3 represent different concentrations of PD-Cl.

[0111] like Figure 5 As shown, the unmodified leveling agent PD has almost no pore-filling ability in the concentration range of 1 to 30 mg / L, and only has pore-filling ability when the concentration reaches 40 mg / L. Figure 6 The modified leveling agent PD-CH3 was at 20-30 mg / L and Figure 7 PD-Cl showed good pore-filling effect in the concentration range of 5 to 20 mg / L, indicating that the leveling agent modified with chlorine atoms can achieve better filling effect at a lower concentration.

[0112] (2) Study on the electrochemical properties of leveling agents:

[0113] Cyclic voltammetric stripping tests were performed on leveling agents PD, PD-CH3, and PD-Cl. Electrochemical tests were conducted using a CHI760e electrochemical workstation in a glass bath containing 50 mL of plating solution. The working electrode was a 5 mm diameter platinum rotating disk electrode (Pt-RDE), and a platinum rod and a saturated mercury-mercurous sulfate electrode (SMSE) were used as the counter and reference electrodes, respectively. The temperature of the plating solution was maintained at 25 °C. During the cyclic voltammetric stripping test, the potential parameters were set to scan from 0.6 V negatively to -0.7 V, and then from -0.7 V positively to 0.6 V. The cathode scan rate was 100 mV / s, and the experiment consisted of 3 scans; the data from the 3rd scan was used for analysis. The additives in the plating solution contained 200 g / L CuSO4•5H2O, 50 g / L H2SO4, and 60 mg / L Cl. - 4 mg / L SPS, 200 mg / L PEG, and different concentrations of leveling agent were used. The working electrode rotation speed was set to 1000 rpm.

[0114] The cyclic voltammetric stripping curve is divided into negative and positive regions. The negative region is the reduction region, where copper ions are reduced to copper on the electrode surface, i.e., the copper deposition region. The positive region is the oxidation region, where the copper deposited on the electrode is oxidized to copper ions, i.e., the copper dissolution region. The amount of copper deposited on the electrode is equal to the amount of copper in the glass. Therefore, the rate of copper ion deposition can be judged by the change in the area of ​​the copper stripping curve region. A larger area indicates that copper ion deposition is promoted, while a smaller area indicates that copper deposition is inhibited. The results are as follows: Figure 8 As shown.

[0115] from Figure 8 It can be seen that the exfoliation peak area of ​​the modified leveling agent PD-Cl is reduced more significantly at the same concentration compared to the unmodified leveling agents PD and PD-CH3, indicating that its ability to inhibit copper deposition is significantly stronger. This further demonstrates that substituent modification can alter the leveling agent's ability to inhibit copper deposition, thereby improving its pore-filling ability.

[0116] (3) Surface morphology test of electroplated coating:

[0117] SEM images of some electroplated samples were performed using PD-Cl, a leveling agent with strong pore-filling ability. SEM images of samples electroplated with different PD-Cl concentrations are shown below. Figure 9 As shown in Table 1, the roughness of the plated sample was scanned using laser confocal microscopy, and the results are statistically presented.

[0118] Table 1 Surface roughness of coating

[0119]

[0120] The results are as follows Figure 9 As shown, it can be observed that the surface of the sample plating obtained by electroplating with the base plating solution (VMS) is rough and uneven with large crystals; the addition of the accelerator SPS and the inhibitor PEG (no leveler) improves the surface roughness of the electroplated sample; while the addition of PD-Cl leveling agent at the same time significantly improves the surface morphology of the electroplated sample, making the surface of the plating more flat and the crystals more delicate; however, when the concentration of PD-Cl is too high, the surface of the plated sample becomes rough and uneven again.

[0121] As can be seen from Table 1, compared with the coating roughness (Ra) of 0.7426µm in the base plating solution, the addition of leveling agent PD-Cl can effectively reduce the surface roughness of the coating, with the lowest roughness being only 0.2425µm, which is more than twice the roughness of the base plating solution.

[0122] In summary, this application discloses a substituent-modified phenazine leveling agent, an acid copper plating solution containing the phenazine, and a preparation method thereof. By introducing chlorine atoms at specific positions of the phenazine, the frontier orbital energy levels of the molecule and its adsorption capacity on the copper substrate are altered. This results in an acid copper plating solution containing the leveling agent achieving a high-brightness coating while also possessing a high porosity, effectively improving the porosity of the leveling agent at lower concentrations. This approach is beneficial for resource conservation and cost reduction. The total synthesis of the chlorine-atom-modified phenazine leveling agent using chlorine-substituted raw materials does not involve complex reaction processes or harsh reaction conditions, making it industrially viable.

[0123] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A substituted phenoxazine smoothening agent, characterized in that, having a molecular structure represented by Formula I: 。 2. The preparation method of the substituent-modified phenazine leveling agent according to claim 1, characterized in that, is prepared by the following route: 。 3. The method for preparing the substituted phenazine leveler according to claim 2, wherein, Step S1, compound 1 is prepared by oxidizing 2-chloroaniline with N,N-dimethyl-p-phenylenediamine dihydrochloride using dichromate; Step S2, compound 2 is prepared by reacting compound 1 with aniline under the catalysis of sodium acetate; Step S3, after compound 2 is reacted with sodium nitrite, compound 2 is further reacted with N,N-dimethylaniline to prepare the compound having the structure represented by Formula I.

4. The method for preparing the substituted phenazine leveler according to claim 2 or 3, wherein, In step S1, 2-chloroaniline and N,N-dimethyl-p-phenylenediamine dihydrochloride are dissolved in water, and a potassium dichromate aqueous solution is added for reaction; The molar ratio of 2-chloroaniline, N,N-dimethyl-p-phenylenediamine dihydrochloride and potassium dichromate is 1:(1-1.2):(1.5-2.5); The reaction temperature is 4-40°C, and the reaction time is 1-2h.

5. The method for preparing the substituted phenazine leveler according to claim 2 or 3, wherein, In step S2, compound 1 and aniline are reacted in an aqueous solvent; The molar ratio of compound 1 and aniline is 1:(1-1.2); sodium acetate is used to adjust the pH to 5-6; The reaction temperature is 90-100°C, and the reaction time is 5-10h.

6. The method for preparing the substituted phenazine leveler according to claim 2 or 3, wherein, In step S3, compound 2 is reacted with sodium nitrite in a hydrochloric acid solution to generate diazonium salt, and then further reacted with N,N-dimethylaniline to prepare the compound having the structure represented by Formula I; The molar ratio of compound 2, sodium nitrite and N,N-dimethylaniline is 1:(1-1.2):(1-1.2); Hydrochloric acid is added in an amount of 10-15 times the molar amount of compound 2; The reaction temperature is 0-5°C, the time for generating diazonium salt is 0.5-2h, and the time for generating compound 2 is 2-5h.

7. The substituted phenazine leveler according to claim 1 is used as a leveler in PCB copper plating.

8. An acid copper plating solution characterized in that, The substituted phenazine leveler according to claim 1.

9. The acid copper plating solution of claim 8, wherein, The acid copper plating solution comprises copper sulfate or a hydrate thereof, sulfuric acid, chloride ions and the substituted phenazine leveler according to claim 1.

10. The acid copper plating solution of claim 8, wherein The acid copper plating solution comprises the following components in the following mass concentrations: 180 to 220 g / L CuSO4.5H2O, 40 to 60 g / L H2SO4, 50 to 70 mg / L Cl - and 5 to 20 mg / L of the substituted group modified phenoxazine leveler of claim 1.

Images