Rapid analysis method of polyethylene glycol additive in copper electrodeposition solution

Abstract

This invention relates to the field of electroplating solution analysis technology, and in particular to a rapid analytical method for polyethylene glycol (PEG) additives in copper electrodeposition solutions. The method involves protonated PEG forming a macromolecular complex colloid with phosphomolybdate under acidic conditions of pH 1.0–2.0. This colloid exhibits maximum absorption at 372 nm, and the absorbance value is directly proportional to the PEG concentration in the formed complex colloid. This allows for quantitative analysis of PEG in the copper electrodeposition solution. Because the phosphomolybdate-PEG complex colloid selected in this invention has excellent selectivity, and no sample pretreatment is required, this invention offers advantages such as ease of operation, speed, high sensitivity, and good selectivity. It is particularly suitable for intermediate control analysis in production environments, such as for electroplated copper interconnects in chips and printed circuit boards, as well as electrolytic copper foil for negative electrode current collectors and copper-clad laminates in energy storage batteries.

Description

Technical Field

[0001] This invention relates to the field of electroplating solution analysis technology, and in particular to a rapid analysis method for polyethylene glycol, an additive in copper electrodeposition solutions. Background Technology

[0002] As is well known, copper interconnects are an indispensable process in chip manufacturing, typically achieved through electroplating with an acidic copper sulfate solution, as is the case with copper interconnects on printed circuit boards (PCBs). In these acidic copper plating solutions, polyethylene glycol (PEG) is a commonly used electroplating additive. With the continuous development of power lithium-ion battery technology, copper foil used for negative electrode current collectors is becoming thinner and stronger with higher tensile strength; simultaneously, PCBs are upgrading towards high-frequency, high-speed signal transmission, placing higher demands on electrolytic copper foil. Therefore, PEG also needs to be added to the electrolyte during the production of electrolytic copper foil. It is evident that PEG is one of the essential additives in acidic copper plating electrolytes.

[0003] Currently, the main methods for detecting PEG include gas chromatography, liquid chromatography, oscillometric polarography, AC voltammetry, iodine precipitation, and barium chloride method, but most of these methods are applicable to the detection of PEG in water samples. Shi Huijuan previously reported an analytical method for determining polyethylene glycol in acidic copper plating solutions using bismuth subcarbonate spectrophotometry, but its drawback is that the plating solution must undergo pretreatment, specifically adjusting the pH of the electrodeposition solution to remove copper ion interference, before the determination can be completed. With the continuous improvement of the precision of chip copper interconnects and the development of electrolytic copper foil towards lower profiles, the precise control of additive concentrations in acidic copper plating solutions is becoming increasingly urgent.

[0004] Therefore, developing an analytical method that requires no pretreatment, has strong anti-interference capabilities, and can quickly and accurately determine the PEG content in acidic copper electrodeposition solutions is a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0005] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies and provide a rapid analytical method for polyethylene glycol (PEG) additives in copper electrodeposition solutions. This invention provides a rapid and quantitative analytical method for determining the PEG content in acidic copper plating solutions without requiring pretreatment, and other coexisting additives in the solution do not affect the PEG determination. This method offers good selectivity, fast analysis speed, and high sensitivity and accuracy, making it highly suitable for process control in acidic copper electrodeposition environments.

[0006] The technical solution adopted by this invention to solve its technical problem is: A rapid analytical method for polyethylene glycol (PEG) additives in copper electrodeposition solutions is disclosed. Under acidic conditions with a pH of 1.0–2.0, PEG in the sample comes into contact with phosphomolybdate to form a phosphomolybdate-PEG colloidal complex. The colloidal complex exhibits maximum absorption at a wavelength of 372 nm using spectrophotometry. The concentration of PEG in the sample is calculated based on a standard curve and linear regression equation established for the relationship between absorbance and PEG concentration.

[0007] In acidic systems, such as those with a pH of 1.0 < pH < 2.0, PEG with its protonated ether oxygen bond (-O-) reacts with phosphomolybdate [PMo], which exists as a stable anion. 12 O 40 ] 3- A stable colloid is formed through electrostatic attraction. The phosphomolybdate-PEG colloid exhibits highly sensitive absorption in the near-ultraviolet region. If the pH is too low (<1.0), the overprotonation of PEG leads to an excessively high positive charge density, potentially causing rapid cross-linking with multiple phosphomolybdate ions, forming irregular precipitates and resulting in an unstable colloid. Simultaneously, phosphomolybdate ions may partially decompose in very strong acids or form other heteropolyacid forms, affecting the stoichiometry and reproducibility of their binding with PEG. If the pH is too high (>2), insufficient protonation of PEG may reduce the effective positive charge, weakening the electrostatic binding force with phosphomolybdate ions, leading to incomplete reactions and a significant decrease in sensitivity. Furthermore, in a weakly acidic environment, phosphomolybdate ions may gradually hydrolyze, reducing their structural stability. Additionally, copper ions (Cu) in the copper electrodeposition solution... 2+ Hydrolysis begins at pH > 4, producing basic salts or copper hydroxide colloids, resulting in significant background turbidity that completely masks the target signal. Therefore, an acidic system with a pH between 1.0 and 2.0 is optimal for the reaction system. If the pH of the reaction system deviates from this range, it can be fine-tuned using dilute sulfuric acid or a corresponding alkaline solution. The alkaline solution is the hydroxide corresponding to the phosphomolybdate ion; for example, sodium phosphomolybdate corresponds to sodium hydroxide.

[0008] Furthermore, the phosphomolybdate is selected from a group 1 phosphomolybdate or ammonium salt, preferably at least one of sodium phosphomolybdate, potassium phosphomolybdate, or ammonium phosphomolybdate.

[0009] Furthermore, the mass ratio of phosphomolybdate to PEG is (35-100):1. If the amount of phosphomolybdate is too small, it will be insufficient to generate phosphomolybdate-PEG colloid; conversely, if too much phosphomolybdate is added, unnecessary side reactions will occur due to the weak oxidizing and complexing abilities of free phosphomolybdate.

[0010] Furthermore, an alcohol stabilizer is added to the reaction system before the formation of the colloidal complex.

[0011] Furthermore, the alcohol stabilizer is selected from at least one of isopropanol, ethylene glycol, and methanol, and its volume fraction in the reaction system is 2-5%.

[0012] Phosphomolybdate [PMo] 12 O 40 ] 3- The colloidal solution formed with protonated PEG exhibits poor stability in the aqueous phase, posing a significant challenge to spectrophotometric analysis. To achieve good dispersion of this colloid in aqueous solution, it was found that adding alcoholic organic solvents provides excellent dispersibility. To avoid affecting subsequent absorbance measurements, the selected organic alcohols should have no absorption in the near-UV region and good solubility in water, such as isopropanol, ethylene glycol, and methanol. The significant improvement in the stability of phosphomolybdic acid-PEG colloids by these alcoholic organic solvents is not achieved through a single chemical action, but rather through a triple mechanism involving the regulation of interfacial charge, solvation layer structure, and steric hindrance between particles. Generally, water has a dielectric constant of 78, while isopropanol has a dielectric constant of 19.9. Therefore, the addition of isopropanol can improve the balance between van der Waals attraction and double-layer repulsion in phosphomolybdic acid-PEG colloids, thereby enhancing their stability. Meanwhile, since isopropanol possesses both hydrophobic isopropyl groups and hydrophilic hydroxyl groups, the surface of the phosphomolybdic acid-PEG complex colloid contains incompletely neutralized negatively charged regions and hydrophobic regions. It is possible that the hydroxyl groups of isopropanol form hydrogen bonds with the polar sites (PEG ether oxygen and phosphomolybdic acid oxygen atoms) on the complex surface, making the phosphomolybdic acid-PEG complex colloid tend to be stable in the aqueous system. Furthermore, phosphomolybdate ions exhibit weak oxidizing properties in strongly acidic solutions. Because the surface of the generated PEG-phosphomolybdic acid colloidal particles contains highly reactive molybdenum centers, these active sites may catalyze the decomposition of the generated colloid or promote chemical cross-linking between particles. However, the hydroxyl groups of isopropanol, through hydrogen bonding with the molybdenum oxygen species on the colloidal particle surface, passivate the surface catalytic activity, preventing further cross-linking and growth of the particles through chemical bonding. Therefore, an alcohol stabilizer is used in this invention, and the alcohol stabilizer is selected from at least one of isopropanol, ethylene glycol, and methanol.

[0013] Furthermore, the rapid analysis method for the additive polyethylene glycol in the copper electrodeposition solution specifically includes the following steps: Step S1: Prepare the acid copper base solution: The components of the acid copper base solution are the same as those of the actual copper electrodeposition solution after removing the additives, and both have the same copper sulfate concentration, sulfuric acid concentration, and chloride ion concentration. Step S2: Prepare PEG standard stock solution; Step S3: Prepare phosphomolybdate solution; Step S4: Preparation of standard working solutions: Transfer equal volumes of the copper acid base solution prepared in step S1 into multiple volumetric flasks, then add different volumes of the PEG standard stock solution prepared in step S2 to each flask, followed by the addition of alcohol stabilizer and the phosphomolybdate solution prepared in step S3. Dilute to volume with water to prepare a set of standard working solutions with gradient PEG concentrations; the pH value of the standard working solutions is 1.0–2.0. Step S5: Plotting the PEG standard curve: After a stable phosphomolybdate-PEG colloidal complex is formed in the standard working solution, the absorbance of a set of standard working solutions prepared in step S4 is measured at a wavelength of 372 nm using a UV-Vis spectrophotometer. The standard curve and linear regression equation are established with PEG concentration as the abscissa and absorbance value as the ordinate. Step S6: Measure the actual sample: Take the copper electrodeposition solution to be tested, add alcohol stabilizer and phosphomolybdate solution in the same order as in step S4, dilute with water, and measure its absorbance at 372 nm wavelength using a UV-Vis spectrophotometer. Step S7: Substitute the absorbance value measured in step S6 into the linear regression equation in step S5 to calculate the concentration of PEG in the sample to be tested.

[0014] Further, in step S2, the concentration of the PEG standard stock solution is 1000 μg / mL. The PEG standard stock solution is prepared as follows: weigh 0.1000 g of PEG, dissolve it in warm water, cool it, transfer it to a 100 mL volumetric flask, and dilute to volume with deionized water to obtain a PEG concentration of 1000 μg / mL. The molecular weight of the PEG is the same as that of the PEG in the sample to be tested.

[0015] Further, in steps S4 and S6, the concentration of the phosphomolybdate solution is 2% (w / v), and the amount of phosphomolybdate added is 1-2.5 mL per 50 mL final volume. The phosphomolybdate solution is prepared by weighing 1.0 g of phosphomolybdate and diluting it with deionized water to a 50 mL volumetric flask.

[0016] Furthermore, in steps S4 and S6, the alcohol stabilizer is selected from at least one of isopropanol, ethylene glycol, and methanol, and the amount of alcohol stabilizer added is 1 to 2.5 mL per 50 mL final volume.

[0017] Furthermore, in step S5, after the phosphomolybdate-PEG colloidal complex is formed, the absorbance is measured within 0.5 hours to ensure the stability of the measurement results.

[0018] Furthermore, the analytical method has a linear detection range of 1.0–10 μg / mL for PEG, and a limit of detection of 0.86 μg / mL.

[0019] The beneficial effects of this invention are that it is rationally designed and has the following advantages: 1. No pretreatment required: The plating solution can be directly diluted for measurement, eliminating the need for cumbersome separation or masking steps, greatly shortening the analysis time. A single analysis can be completed within 10 minutes. 2. High selectivity and strong anti-interference ability: Under optimized conditions, the detection signal originates only from the specific colloid formed by PEG and phosphomolybdate. High concentrations of copper ions, chloride ions, and conventional organic additives (such as SPS and MTZ) in the plating bath do not exhibit absorption at 372 nm and will not interfere with the measurement results. 3. High sensitivity, accurate and reliable: Utilizing the absorption enhancement effect of colloidal systems, it exhibits high detection sensitivity and good linearity (R0). 2 >0.996), and both the recovery rate and precision meet the requirements for industrial analysis; 4. Easy to operate and low cost: Only a conventional UV-Vis spectrophotometer is needed to complete the detection, making it easy to promote and use in production sites. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 The images show the UV absorption spectra (A) and standard curve (B) of the phosphomolybdate-PEG colloidal complexes at different PEG concentrations in Example 1 of this invention. The standard curve equation is A = 0.03451C - 0.0065, R² = 0.9962.

[0022] Figure 2 The image shows the UV absorption spectrum of PEG and SPS coexisting in the copper electrodeposition solution in Example 1 of this invention, indicating that SPS does not significantly interfere with the determination of PEG.

[0023] Figure 3 The image shows the ultraviolet absorption spectrum of PEG and MTZ coexisting in the copper electrodeposition solution in Example 1 of this invention. It indicates that MTZ causes some interference at 300 nm, but this can be avoided by adjusting the detection wavelength. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0025] For ease of comparison and illustration, a copper electrodeposition solution similar to that used in actual production was prepared as the test sample (used in the following examples and comparative examples). Its composition was 150 g / L copper sulfate, 100 g / L sulfuric acid, and Cl...- 50 μg / mL and PEG6000 60 μg / mL. The analytical method of the present invention is described by quantitative analysis of PEG in the test sample.

[0026] In the stability test of the generated phosphomolybdate-PEG colloid, the rate of change of absorbance value ΔA within 30 min was considered, and ΔA < 5%. When ΔA > 5%, the analytical conditions are unacceptable because the generated colloid is unstable.

[0027] In copper electrodeposition solutions, PEG is often used as an additive in addition to other additives such as sodium polydithiopropane sulfonate (SPS) and 2-mercaptothiazoline (MTZ). These additives are frequently used in combination with PEG. Therefore, the addition of SPS and MTZ is described in the embodiments of this invention. However, it should be noted that the scope of protection of this invention is not limited to the following embodiments.

[0028] Example 1: The rapid analysis method for the additive polyethylene glycol in the copper electrodeposition solution of this embodiment specifically includes the following steps: Step S1: Prepare copper sulfate base solution: Prepare a copper sulfate base solution with the same composition as the sample to be tested, excluding additives. Its composition is 150 g / L copper sulfate, 100 g / L sulfuric acid, and Cl... - 50 μg / mL; Step S2: Prepare PEG standard stock solution: Accurately weigh 0.1000 g of PEG6000 with the same molecular weight as the additive in the sample to be tested, and make up to 100 mL with deionized water to prepare a PEG standard stock solution with a concentration of 1000 μg / mL. Step S3, Preparation of sodium phosphomolybdate solution: Prepare 2% (w / v) sodium phosphomolybdate solution: Weigh 1.0 g of sodium phosphomolybdate and dilute to 50 mL in a volumetric flask with deionized water; Step S4: Preparation of standard working solutions: Transfer 1 mL of the copper acid base solution prepared in step S1 into five 50 mL volumetric flasks, add an appropriate amount of deionized water, and cool to room temperature. Then, add 1000 μg / mL of the PEG standard stock solution prepared in step S2 to the above 50 mL volumetric flasks, with volumes of 0, 0.05, 0.15, 0.25, 0.35, and 0.5 mL, respectively. Next, add 1 mL of isopropanol, an alcohol stabilizer, to each of the above volumetric flasks to bring the final concentration to 2% (v / v). Finally, add 1 mL of 2% (w / v) sodium phosphomolybdate solution and dilute to 50 mL with deionized water to obtain a set of standard working solutions with gradient PEG concentrations of 0, 1, 3, 5, 7, and 10 μg / mL. The pH value of the standard working solutions is 1.5. Step S5: After a stable phosphomolybdate-PEG colloidal complex is formed in the standard working solutions, the absorption spectra of the set of standard working solutions prepared in step S4 are measured using a UV-Vis spectrophotometer in the wavelength range of 280–600 nm. The results are as follows: Figure 1 As shown in A; Figure 1 It can be seen that the colloidal complex has sensitive absorption at 372 nm. The absorbance value at 372 nm was recorded, and then a standard curve was plotted with PEG concentration on the x-axis and absorbance value at 372 nm on the y-axis (e.g., ...). Figure 1 As shown in B), the linear regression equation is: A = 0.0386C + 0.04619 (correlation coefficient R). 2 = 0.9969), where A is the absorbance value and C is the PEG concentration (μg / mL); Step S6: Determine the actual sample: Take 1 mL of the sample to be tested into a 50 mL volumetric flask, add an appropriate amount of deionized water and cool to room temperature, then add 1 mL of isopropanol, then add 1 mL of 2% sodium phosphomolybdate solution, and dilute to 50 mL with deionized water. The pH value of the actual sample is 1.5. Use a UV-Vis spectrophotometer to measure its absorbance value at a wavelength of 372 nm. Step S7: Substitute the absorbance value measured in step S6 into the linear regression equation in step S5 to calculate the concentration of PEG in the sample to be tested.

[0029] To investigate the effect of chloride ion concentration on PEG analysis, the chloride ion concentration of the acidic copper plating solution (sample) was increased to 100 μg / mL. Using the analytical method of this embodiment, the measured PEG result was 59.7 μg / mL, which is almost identical to the added PEG value of 60 μg / mL, further demonstrating the accuracy and efficiency of the present invention's determination method. Typically, the chloride ion concentration constituting the acidic copper solution does not exceed 100 μg / mL; therefore, it can be considered that the coexisting chloride ions do not affect the PEG analysis.

[0030] To investigate the stability of the generated phosphomolybdate-PEG colloidal complex dispersed in aqueous solution, the rate of change of absorbance ΔA after 30 minutes was recorded. The results are shown in Table 1.

[0031] Example 2: The rapid analysis method in this embodiment differs from that in Embodiment 1 in that steps S4 to S7 are as follows: After adding 1 mL of copper sulfate base solution and PEG standard stock solution, add 1.5 mL of ethylene glycol stabilizer, then add 2 mL of 2% ammonium phosphomolybdate solution, and finally dilute to 50 mL with deionized water. The pH of the standard working solution at this point is 1.5. Measure the absorbance at 372 nm. The linear regression equation for absorbance value versus PEG concentration is A = 0.03753C + 0.04486 (correlation coefficient R0). 2 = 0.9981).

[0032] Take 1 mL of the sample to be tested, and perform the analysis in complete accordance with the standard curve analysis method for PEG described above. Measure the absorbance at 372 nm using a UV-Vis spectrophotometer. The concentration of PEG in the sample can be calculated using the linear regression equation for PEG obtained above, and the results are listed in Table 1.

[0033] Sodium poly(dipropanedisulfonate) sulfonate (SPS), a common additive added to acidic copper electrodeposition solutions, typically does not exceed 10 μg / mL. Therefore, to investigate the effect of the coexisting additive SPS on PEG analysis, PEG was removed and replaced with 10 μg / mL SPS when preparing the test samples. The absorption spectra results for samples containing SPS and PEG respectively are shown below. Figure 2 As shown, from Figure 2The results show that the addition of SPS does not affect the analysis and detection of PEG. To realistically examine the effect of the presence of SPS on PEG analysis, a concentration of 10 μg / mL of SPS was added to the copper electrodeposition solution in Example 1. The measured PEG concentration at this time was 60.01 μg / mL. By increasing the concentration of SPS, the effect of SPS on PEG determination was examined. When the PEG concentration was 60 μg / mL, even when the SPS concentration was five times that of PEG (i.e., 300 μg / mL), the measurement error was less than 4.6%.

[0034] To investigate the stability of the generated phosphomolybdate-PEG colloidal complex dispersed in aqueous solution, the rate of change of absorbance ΔA after 30 minutes was recorded. The results are shown in Table 1.

[0035] Example 3: The rapid analysis method in this embodiment differs from that in Embodiment 1 in that steps S4 to S7 are as follows: After adding 1 mL of copper sulfate base solution and PEG standard stock solution, add 2 mL of isopropanol as a stabilizer, then add 2.5 mL of 2% potassium phosphomolybdate solution, and finally dilute to 50 mL with deionized water. The pH of the standard working solution at this point is 1.5. Measure the absorbance at 372 nm. The linear regression equation for absorbance value versus PEG concentration is A = 0.03665C + 0.04391 (correlation coefficient R0). 2 = 0.9991).

[0036] Take 1 mL of the sample to be tested, and perform the analysis in complete accordance with the standard curve analysis method for PEG described above. Measure the absorbance at 372 nm using a UV-Vis spectrophotometer. The concentration of PEG in the sample can be calculated using the linear regression equation for PEG obtained above, and the results are listed in Table 1.

[0037] 2-Mercaptothiazoline (MTZ) is typically added to copper electrodeposition solutions at concentrations ranging from approximately 10 μg / mL. Therefore, to investigate the effect of the coexisting additive MTZ on PEG analysis, PEG was removed and replaced with 10 μg / mL MTZ when preparing the test samples. The absorption spectra of samples containing MTZ and PEG, respectively, are shown below. Figure 3 As shown, from Figure 3 The results showed that MTZ has a very sensitive absorption peak at 290 nm, but it has no effect on the analysis of PEG at 372 nm. To realistically examine the effect of MTZ concentration on PEG analysis, 10 μg / mL of MTZ was added to the copper electrodeposition solution in Example 1. The measured PEG concentration at this time was 59.6 μg / mL.

[0038] By increasing the concentration of MTZ, the effect of MTZ on PEG determination was investigated. When the concentration of PEG was 60 μg / mL, even if the concentration of MTZ was 3.5 times that of PEG, i.e. 210 μg / mL, the measurement error of PEG at 372 nm was less than 4.8%.

[0039] To investigate the stability of the generated phosphomolybdate-PEG colloidal complex dispersed in aqueous solution, the rate of change of absorbance ΔA after 30 minutes was recorded. The results are shown in Table 1.

[0040] Comparative Example 1: The copper electrodeposition solution used was exactly the same as in Example 1, and the analytical procedure was also the same as in Example 1. The difference was that after the analytical solution was prepared, the pH was adjusted to 3.0 with sodium hydroxide solution, and then the volume was brought to 50 mL with deionized water. Absorbance analysis was performed at 372 nm using a UV-Vis spectrophotometer, and the linear regression equation of absorbance value on PEG concentration was obtained as A = 0.03731C + 0.04364 (correlation coefficient R0). 2 = 0.9936), the concentration of PEG can be calculated and the results are shown in Table 1.

[0041] To investigate the stability of the generated phosphomolybdate-PEG colloidal complex dispersed in aqueous solution, the rate of change of absorbance ΔA after 30 minutes was recorded. The results are shown in Table 1.

[0042] Comparative Example 2: The copper electrodeposition solution was identical to that used in Example 1, and the analytical procedures were also the same as in Example 1. The difference was that no organic alcohol stabilizer was added to the reaction solution. Absorbance analysis was performed at 372 nm using a UV-Vis spectrophotometer, and the linear regression equation for absorbance values ​​against PEG concentration was obtained: A = 0.03828C + 0.04328 (correlation coefficient R0). 2 =0.9928), the concentration of PEG can be calculated and the results are shown in Table 1.

[0043] To investigate the stability of the generated phosphomolybdate-PEG colloidal complex dispersed in aqueous solution, the rate of change of absorbance ΔA after 30 minutes was recorded. The results are shown in Table 1.

[0044] Comparative Example 3: The copper electrodeposition solution used was identical to that in Example 1, and the analytical procedure was also the same as in Example 1. The difference was that the amount of sodium phosphomolybdate solution added was increased. Specifically, 1 mL of copper electrodeposition solution and PEG standard solution were added, followed by 1 mL of isopropanol. Then, 3 mL of 2% sodium phosphomolybdate solution was added to the above PEG standard solution, and the volume was adjusted to 50 mL with deionized water. Absorbance analysis was performed at 372 nm using a UV-Vis spectrophotometer, and the linear regression equation of absorbance value on PEG concentration was obtained as A = 0.03741C + 0.04408 (correlation coefficient R). 2 = 0.9891), the concentration of PEG can be calculated and the results are shown in Table 1.

[0045] To investigate the stability of the generated phosphomolybdate-PEG colloidal complex dispersed in aqueous solution, the rate of change of absorbance ΔA after 30 minutes was recorded. The results are shown in Table 1.

[0046] Table 1

[0047] Note: a. Average of three measurements taken for sample. As shown in Table 1, the samples were measured in triplicate. The PEG results obtained in the examples showed good precision, with RSDs all less than 3%. Furthermore, the measured values ​​had very small errors compared to the actual added concentration of 60 μg / mL PEG, indicating that the analytical method of this invention has excellent accuracy. Moreover, since additives such as SPS and MTZ coexisting in the copper electrodeposition solution do not affect the PEG determination, this invention provides an accurate analytical method for PEG analysis, laying a solid foundation for process control in production.

[0048] In summary, this invention relates to a rapid and accurate analytical method for analyzing the concentration of polyethylene glycol (PEG) additive in copper electrodeposition solutions during the production processes of copper interconnects between chips and printed circuit boards, copper-clad laminates, and electrolytic copper foil for current collectors in energy storage batteries. The aim is to achieve effective control over the PEG additive. Specifically, this method utilizes the electrostatic binding of protonated PEG with phosphomolybdate ions to form a macromolecular colloidal complex. This colloidal complex exhibits a maximum absorption peak at 372 nm, and the concentration of PEG additive in the copper electrodeposition solution is detected by spectrophotometry.

[0049] The analytical method of this invention requires no sample pretreatment, significantly shortening the analysis time and making it highly suitable for rapid process control in electrolytic copper foil production. Furthermore, this method enables accurate quantitative analysis of PEG, rather than semi-quantitative detection, and exhibits strong anti-interference capabilities. Based on these advantages, this invention is beneficial for quality control and process optimization of acidic copper plating electrolytes.

[0050] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A rapid analytical method for polyethylene glycol, an additive in copper electrodeposition solutions, characterized in that: Under acidic conditions with a pH of 1.0–2.0, PEG in the test sample comes into contact with phosphomolybdate to form a phosphomolybdate-PEG colloidal complex. The colloidal complex exhibits maximum absorption at a wavelength of 372 nm using spectrophotometry. Based on the established standard curve of absorbance versus PEG concentration and the linear regression equation, the concentration of PEG in the test sample is calculated.

2. The rapid analysis method for polyethylene glycol additive in copper electrodeposition solution according to claim 1, characterized in that: The phosphomolybdate is selected from at least one of sodium phosphomolybdate, potassium phosphomolybdate, or ammonium phosphomolybdate.

3. The rapid analytical method for the additive polyethylene glycol in the copper electrodeposition solution according to claim 1, characterized in that: The mass ratio of the phosphomolybdate to PEG is (35-100):

1.

4. The rapid analytical method for the additive polyethylene glycol in the copper electrodeposition solution according to claim 1, characterized in that: An alcohol stabilizer is added to the reaction system before the formation of the colloidal complex.

5. The rapid analysis method for polyethylene glycol additive in copper electrodeposition solution according to claim 4, characterized in that: The alcohol stabilizer is selected from at least one of isopropanol, ethylene glycol, and methanol, and its volume fraction in the reaction system is 2-5%.

6. The rapid analytical method for the additive polyethylene glycol in the copper electrodeposition solution according to claim 1, characterized in that: Specifically, the steps include the following: Step S1: Prepare the acid copper base solution: The components of the acid copper base solution are the same as those of the actual copper electrodeposition solution after removing the additives, and both have the same copper sulfate concentration, sulfuric acid concentration, and chloride ion concentration. Step S2: Prepare PEG standard stock solution; Step S3: Prepare phosphomolybdate solution; Step S4: Prepare standard working solutions: Transfer equal amounts of the copper acid base solution prepared in step S1 into multiple volumetric flasks, then add different volumes of the PEG standard stock solution prepared in step S2, and then add alcohol stabilizer and phosphomolybdate solution prepared in step S3 in sequence. Dilute to volume with water to prepare a set of standard working solutions with gradient PEG concentrations. The pH value of the standard working solution is 1.0–2.0; Step S5: Plotting the PEG standard curve: After a stable phosphomolybdate-PEG colloidal complex is formed in the standard working solution, the absorbance of a set of standard working solutions prepared in step S4 is measured at a wavelength of 372 nm using a UV-Vis spectrophotometer. The standard curve and linear regression equation are established with PEG concentration as the abscissa and absorbance value as the ordinate. Step S6: Measure the actual sample: Take the copper electrodeposition solution to be tested, add alcohol stabilizer and phosphomolybdate solution in the same order as in step S4, dilute with water, and measure its absorbance at 372 nm wavelength using a UV-Vis spectrophotometer. Step S7: Substitute the absorbance value measured in step S6 into the linear regression equation in step S5 to calculate the concentration of PEG in the sample to be tested.

7. The rapid analytical method for the additive polyethylene glycol in the copper electrodeposition solution according to claim 6, characterized in that: In step S2, the concentration of the PEG standard stock solution is 1000 μg / mL.

8. The rapid analytical method for the additive polyethylene glycol in the copper electrodeposition solution according to claim 6, characterized in that: In steps S4 and S6, the concentration of the phosphomolybdate solution is 2% (w / v), and the amount of phosphomolybdate added is 1 to 2.5 mL per 50 mL final volume.

9. The rapid analytical method for the additive polyethylene glycol in the copper electrodeposition solution according to claim 6, characterized in that: In steps S4 and S6, the alcohol stabilizer is selected from at least one of isopropanol, ethylene glycol, and methanol, and the amount of alcohol stabilizer added is 1 to 2.5 mL per 50 mL final volume.

10. The rapid analytical method for the additive polyethylene glycol in the copper electrodeposition solution according to claim 1, characterized in that: The analytical method exhibits a linear detection range of 1.0–10 μg / mL for PEG, with a limit of detection of 0.86 μg / mL.

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