Electroplating monitoring method and system for probe

Abstract

The invention relates to an electroplating monitoring method and system for a probe. The method comprises the following steps: continuously collecting a plating solution from a main plating tank by using a circulating pump, conveying the plating solution to a test tank, and scanning the plating solution in the test tank based on a preset scanning interval time by using a cyclic voltammetry to obtain a cyclic voltammetry curve; performing characteristic analysis on the basis of the cyclic voltammetry curve to obtain a characteristic signal value; inputting the characteristic signal value into a preset calibration model to calculate the current additive concentration in real time; and comparing the current additive concentration with a preset concentration range to obtain a concentration adjustment scheme. According to the scheme, the concentration of the nickel plating solution additive can be monitored online in real time, and accurate control over probe bending is achieved.

Description

Technical Field

[0001] This application relates to the field of electroplating technology, and in particular to an electroplating monitoring method and system using a probe. Background Technology

[0002] In the electroplating industry, trace amounts of organic additives (such as brighteners, leveling agents, and wetting agents) play a crucial role in the quality of the plating layer (such as gloss, smoothness, and toughness). These additives are continuously consumed and decomposed during the production process, and their concentration must be maintained within a narrow optimal range. Too low a concentration will result in a rough and dull plating layer; too high a concentration may cause increased brittleness of the plating layer and defects such as streaks.

[0003] Thin-film probe cards are core interface tools for semiconductor wafer testing, typically containing tens of thousands of microprobes. Currently, nickel plating solutions are widely used in probe production for electroplating the probe body. However, high stress in the nickel plating layer can significantly affect probe bending, reducing the yield of probes processed in the same batch. Nickel plating solution alone exhibits significant tensile stress, necessitating the addition of boron source additives to counteract this stress and bring the overall plating stress close to zero. However, boron source additives are consumed rapidly during electroplating, requiring continuous monitoring and replenishment. Therefore, an online, real-time monitoring method is urgently needed.

[0004] In industry, monitoring the concentration of additives in plating solutions mainly relies on offline analytical methods such as high-performance liquid chromatography (HPLC) or periodic Hull cell tests. These methods have significant time lags: the cycle from sampling and testing to analysis completion is lengthy, and they cannot capture the dynamic changes in the state of the plating solution in real time. This results in a lack of timeliness and accuracy in additive replenishment strategies, which can easily lead to fluctuations in the quality of batch products and cause ineffective consumption of additives and waste of resources. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a method and system for monitoring the electroplating of probes, which can monitor the concentration of additives in nickel plating solution in real time and online, thereby achieving precise control over the probe electroplating production process.

[0006] Therefore, in a first aspect, the present invention provides a method for monitoring the electroplating of a probe, comprising:

[0007] A circulating pump is used to continuously collect plating solution from the main electroplating tank and transport it to the test tank. The cyclic voltammetry curve is obtained by scanning the plating solution in the test tank based on a preset scanning interval.

[0008] Based on the aforementioned cyclic voltammetry curve, characteristic signal values ​​are obtained through characteristic analysis.

[0009] The characteristic signal value is input into a preset calibration model to calculate the current additive concentration in real time; the current additive concentration is compared with a preset concentration range to obtain a concentration adjustment scheme.

[0010] In some embodiments, the feature analysis includes extracting the peak current or peak area of ​​the characteristic peaks that appear on the cyclic voltammetry curve at a specific potential as the feature signal value.

[0011] In some embodiments, the process of establishing the preset calibration model includes: configuring multiple test plating solutions with different known concentrations of additives, scanning each test plating solution by cyclic voltammetry to obtain cyclic voltammetric curves, extracting test feature signal values ​​based on the cyclic voltammetric curves through feature analysis, and performing linear regression fitting with the known concentration as the dependent variable and the corresponding test feature signal value as the independent variable to obtain the calibration model.

[0012] In some embodiments, the concentration adjustment scheme includes: if the current additive concentration in the plating solution is lower than the preset concentration range, then adding an appropriate amount of the additive to the main electroplating tank; if the current additive concentration is higher than the preset concentration range, then issuing an alarm.

[0013] In some embodiments, the method further includes re-verifying the plating solution after the additive has been added. If the concentration of the additive in the plating solution is within the preset concentration range, real-time monitoring continues. If the concentration of the additive in the plating solution is still less than the preset concentration range, an appropriate amount of additive is added and the verification is performed again. If the concentration of the additive in the plating solution is greater than the preset concentration range, an alarm is issued to achieve closed-loop control.

[0014] A real-time monitoring system for electroplating, configured to perform the method described in any one of the above methods, the system comprising:

[0015] An online sampling module, including a main electroplating tank and a circulation pump connected to the main electroplating tank, is configured to continuously collect plating solution from the main electroplating tank.

[0016] An electrochemical detection module, including a test tank, a three-electrode unit, and an electrochemical workstation electrically connected to the three-electrode unit, is configured to perform cyclic voltammetry scanning on the three-electrode unit via the electrochemical workstation to detect the plating solution added to the test tank in real time and obtain cyclic voltammetry data.

[0017] The data analysis module is used to analyze the cyclic voltammetry data obtained from the electrochemical detection module to obtain characteristic signal values, and to calculate the current additive concentration in real time based on the characteristic signal values.

[0018] An automatic replenishment module, including at least one metering pump and at least one additive storage tank, is used to replenish additives to the main electroplating tank.

[0019] The control module is communicatively connected to the online sampling module, electrochemical detection module, data analysis module, and automatic replenishment module. It is used to automatically activate an alarm or control the metering pump in the automatic replenishment module to add a fixed amount of additive to the main electroplating tank based on the current additive concentration obtained by the data analysis module.

[0020] In some embodiments, the three-stage unit includes a working electrode, a counter electrode, and a reference electrode.

[0021] In some embodiments, the three-electrode unit is immersed in the plating solution in the test tank.

[0022] In some embodiments, when the current additive concentration is lower than the preset concentration range, the control module sends a pulse signal to the metering pump, and the metering pump pumps a fixed volume of the additive into the main electroplating tank; if the current additive concentration is higher than the preset concentration range, the control module automatically activates an alarm.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] By employing automatic sampling and cyclic voltammetry scanning, the compositional changes of the nickel plating bath are instantaneously acquired, and the electrochemical signals are converted into concentration values ​​in real time according to a preset calibration model, thereby enabling online monitoring of the boron source additive content. This technology transforms traditional offline analysis into continuous process monitoring, resulting in high precision and rapid response in boron source additive concentration control. It achieves real-time and accurate regulation of nickel plating additive concentration, effectively supporting the stable operation and process optimization of the electroplating production probe process. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a real-time monitoring system for electroplating provided in an embodiment of this application.

[0026] Figure 2 A schematic diagram of the structure of a real-time monitoring system for electroplating provided in this application embodiment.

[0027] Figure 3 This is a schematic flowchart of a probe electroplating monitoring method provided in an embodiment of this application.

[0028] Figure 4 This is a schematic diagram of the cyclic voltammetry curve provided in an embodiment of this application.

[0029] Figure 5This is a schematic diagram illustrating the relationship between peak current and concentration, provided in an embodiment of this application.

[0030] Figure 6 This is a schematic diagram showing the concentration trend of the control interface provided in the embodiments of this application.

[0031] The components include: 100. Electroplating real-time monitoring system; 1. Main electroplating tank; 2. Circulation pump; 3. Test tank; 4. Three-electrode unit; 5. Electrochemical workstation; 6. Metering pump; and 7. Industrial computer. Detailed Implementation

[0032] To illustrate the technical content, structural features, achieved objectives, and effects of the invention in detail, the technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. In the following description, for illustrative purposes, numerous specific details are set forth to provide a detailed description of various exemplary embodiments or implementations of the invention. However, various exemplary embodiments may also be implemented without these specific details or in one or more equivalent arrangements. Furthermore, the various exemplary embodiments may differ, but are not necessarily exclusive. For example, the specific shape, construction, and characteristics of the exemplary embodiments may be used or implemented in another exemplary embodiment without departing from the inventive concept.

[0033] In the following description, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0034] See Figure 1 and Figure 2 This invention provides a real-time electroplating monitoring system 100, including a main electroplating tank 1, a circulating pump 2, a test tank 3, a three-electrode unit 4, an electrochemical workstation 5, a metering pump 6, and an industrial computer 7. The functional modules constructed from the above equipment include an online sampling module 201, an electrochemical detection module 202, a data analysis module 203, an automatic replenishment module 204, and a control module 205. The control module is communicatively connected to the online sampling module, the electrochemical detection module, the data analysis module, and the automatic replenishment module.

[0035] The online sampling module 201 includes a main electroplating tank 1 and one or more circulation pumps 2 connected to the main electroplating tank 1, and is configured to continuously collect plating solution into the main electroplating tank 1. In this embodiment, the plating solution is a nickel plating solution.

[0036] The electrochemical detection module 202 includes a test tank 3, a three-electrode unit 4, and an electrochemical workstation 5 electrically connected to the three-electrode unit 4. It is configured to perform cyclic voltammetry scanning on the three-electrode unit 4 via the electrochemical workstation 5 to obtain cyclic voltammetric data in real time from the plating solution added to the test tank 3. The test tank 3 has a small volume and is made of corrosion-resistant materials such as polyvinyl chloride. The three-electrode unit 4 is immersed in the plating solution in the test tank 3, ensuring full contact with the solution and improving the accuracy of data acquisition.

[0037] In this embodiment, the three-electrode unit 4 includes a working electrode WE, a counter electrode CE, and a reference electrode RE. The working electrode is preferably a rotating disk electrode, and its rotation speed is controlled to enhance mass transfer. The counter electrode is an inert electrode, such as a platinum wire electrode. The reference electrode is selected according to the plating solution system and can be a mercurous sulfate electrode or an Ag / AgCl electrode. In one preferred embodiment, for acidic nickel plating solutions, a mercurous sulfate electrode is preferred to provide a stable potential reference.

[0038] In this embodiment, the circulating pump 2 connects the main electroplating tank 1 and the test tank 3 through a corrosion-resistant pipeline to form a closed bypass. It is configured to continuously draw out the plating solution in the main electroplating tank 1 at a constant and slow flow rate (e.g., 10 mL / min) and deliver it to the test tank 3 to ensure the real-time nature and representativeness of the test samples.

[0039] Data analysis module 203 is used to analyze the cyclic voltammetry data obtained from electrochemical detection module 202 to obtain characteristic signal values, and calculate the current additive concentration in real time based on the characteristic signal values;

[0040] The automatic replenishment module 204 includes at least one metering pump 6, particularly a precision metering pump, the inlet of which is connected to an additive storage tank (not shown in the figure), and the outlet of which is connected to the main electroplating tank 1 via a pipeline, for replenishing additives to the main electroplating tank 1. A peristaltic pump is preferably used to achieve high-precision quantitative addition.

[0041] The control module 205 is used to automatically start an alarm or control the metering pump 6 in the automatic replenishment module to add a certain amount of additive to the main electroplating tank 1 based on the current additive concentration obtained by the data analysis module.

[0042] The industrial computer 7 is capable of implementing the data analysis module 203 and the control module 205.

[0043] In a preferred embodiment, the system consists of a test tank 3 made of polyvinyl chloride connected to the main electroplating tank 1 (acidic nickel plating tank) via a pipe. A small circulating pump 2 drives the plating solution to flow through the test tank 3 at a flow rate of 10 mL / min. A three-electrode unit 4 is installed inside the test tank 3: the working electrode is a glassy carbon rotating disk electrode (rotation speed controlled at 500 rpm), the counter electrode is a platinum wire, and the reference electrode is a mercury-mercurous sulfate reference electrode. The three-electrode unit 4 is connected to an electrochemical workstation 5. The electrochemical workstation 5 communicates with an industrial computer 7 via a USB cable.

[0044] Based on the above system, such as Figure 3 As shown, the present invention provides a method for monitoring the electroplating of a probe, comprising:

[0045] A circulating pump 2 continuously collects plating solution from the main electroplating tank 1 and delivers it to the test tank 3. An electrochemical workstation 5 applies a triangular wave potential scan to the three-electrode unit 4, consisting of the working electrode (WE), counter electrode (CE), and reference electrode (RE), to obtain a cyclic voltammetric curve of the plating solution in the test tank 3 in real time. The scan is performed cyclically based on a preset scan interval (e.g., once every 5 minutes). In this embodiment, the circulating pump 2 operates continuously to ensure that the test tank 3 always contains fresh plating solution.

[0046] The electrochemical workstation 5 transmits the obtained cyclic voltammetry curve to the industrial computer 7. Based on the cyclic voltammetry curve, the industrial computer 7 identifies the characteristic peaks appearing at specific potentials through characteristic analysis and accurately calculates the peak current or peak area (representing the amount of charge) of the characteristic peak. Substituting the peak current or peak area of ​​this characteristic peak into the stored calibration model, the current additive concentration in the plating solution is calculated.

[0047] The current additive concentration in the plating solution is compared with the preset concentration range. If the current additive concentration in the plating solution is lower than the preset concentration range, the control module 205 sends a pulse signal to the metering pump 6, and the metering pump 6 pumps a fixed volume of additive into the main electroplating tank 1. If the current additive concentration in the plating solution is higher than the preset concentration range, the control module 205 will automatically start an alarm.

[0048] In this embodiment, after the additive addition operation, the system does not stop working but continues to periodically monitor the plating solution after the additive has been added (for the next 5 minutes). This round of monitoring automatically verifies the effect of the previous addition: it calculates the concentration of the additive in the plating solution. If it returns to the target range, the system maintains a stable monitoring state; if it is still below the lower limit, the addition procedure is restarted; if it unexpectedly exceeds the upper limit, an alarm is immediately triggered. This cycle of "monitoring → decision → execution → re-monitoring" constitutes a complete closed-loop control, ensuring that the additive concentration can be dynamically stabilized within the optimal process window.

[0049] In this embodiment, the process of establishing the preset calibration model includes: configuring multiple test plating solutions with different known concentrations of boron source additives; scanning each test plating solution using cyclic voltammetry to obtain cyclic voltammetric curves; extracting test feature signal values ​​based on the cyclic voltammetric curves through feature analysis; and performing linear regression fitting with the known concentration as the dependent variable and the corresponding test feature signal value as the independent variable to obtain the calibration model. The calibration model is a calibration equation, specifically C = k*ip+b (where C is the known concentration, ip is the corresponding test feature signal value, k is the coefficient, and b is the constant term).

[0050] In one specific embodiment, a series of fresh acidic nickel standard solutions containing known concentrations of boron source additives (e.g., 0.5, 1.0, 2.0, 3.0 mL / L) were prepared. For each standard solution, cyclic voltammetry scans were performed using the system described above (scan range -0.3V to +0.5V (relative to the mercurous sulfate reference electrode), scan rate 50 mV / s). Figure 4 As shown, the cyclic voltammetry curve exhibits a distinct reduction peak at approximately -0.1 V, which is correlated with the concentration of the boron source additive. The peak current value of this reduction peak was measured, and a graph showing the relationship between peak current and concentration was plotted, as shown below. Figure 5 As shown. Through linear regression fitting, the calibration equation was obtained: C (mL / L) = 0.25 * ip (mA) + 0.02. This equation was stored in the monitoring software of the industrial computer. The monitoring software automatically performs a cyclic voltammetric scan every 5 minutes. After each scan, the software automatically identifies the reduction peak near -0.1V, reads its peak current value, and substitutes it into the calibration equation to immediately calculate the current concentration of the boron source additive. Figure 6 As shown, the concentration value is displayed in real-time on the trend graph of the control interface. The operator sets the target range for the boron source additive concentration in the software to 1.8-2.2 mL / L. When the system detects a concentration below 1.8 mL / L, the industrial computer 7 sends a pulse signal to the precision metering pump 6 connected to the boron source additive storage tank, pumping in a fixed volume (e.g., 10 mL) of additive. The system verifies whether the concentration has returned to the target range in the next measurement cycle, thus achieving closed-loop control.

[0051] Traditional methods mainly use offline liquid chromatography to detect the concentration of additives in nickel plating solutions, with a probe bending pass rate of 49%. After adopting this method, the probe bending pass rate reaches 97%.

[0052] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope. The scope of protection of the present invention is defined by the appended claims, specification, and their equivalents.

Claims

1. A method for monitoring the electroplating of a probe, characterized in that, include: A circulating pump is used to continuously collect plating solution from the main electroplating tank and transport it to the test tank. The cyclic voltammetry curve is obtained by scanning the plating solution in the test tank based on a preset scanning interval. Based on the aforementioned cyclic voltammetry curve, characteristic signal values ​​are obtained through characteristic analysis. The characteristic signal value is input into a preset calibration model to calculate the current additive concentration in real time; the current additive concentration is compared with a preset concentration range to obtain a concentration adjustment scheme.

2. The method according to claim 1, characterized in that, The feature analysis includes extracting the peak current or peak area of ​​the characteristic peaks that appear in the cyclic voltammetry curve at a specific potential as the characteristic signal value.

3. The method according to claim 1, characterized in that, The process of establishing the preset calibration model includes: configuring multiple test plating solutions with different known concentrations of additives; scanning each test plating solution using cyclic voltammetry to obtain cyclic voltammetric curves; extracting test feature signal values ​​based on the cyclic voltammetric curves through feature analysis; and performing linear regression fitting with the known concentration as the dependent variable and the corresponding test feature signal value as the independent variable to obtain the calibration model.

4. The method according to claim 1, characterized in that, The concentration adjustment scheme includes: if the current additive concentration in the plating solution is lower than the preset concentration range, then an appropriate amount of the additive is added to the main electroplating tank; if the current additive concentration is higher than the preset concentration range, then an alarm is issued.

5. The method according to claim 4, characterized in that, It also includes re-verifying the plating solution after the additive is added. If the concentration of the additive in the plating solution is within the preset concentration range, real-time monitoring continues. If the concentration of the additive in the plating solution is still less than the preset concentration range, an appropriate amount of additive is added and the verification is performed again. If the concentration of the additive in the plating solution is greater than the preset concentration range, an alarm is issued to achieve closed-loop control.

6. A real-time monitoring system for electroplating, configured to perform the method according to any one of claims 1-5, characterized in that, The system includes: An online sampling module, including a main electroplating tank and a circulation pump connected to the main electroplating tank, is configured to continuously collect plating solution from the main electroplating tank. An electrochemical detection module, including a test tank, a three-electrode unit, and an electrochemical workstation electrically connected to the three-electrode unit, is configured to perform cyclic voltammetry scanning on the three-electrode unit via the electrochemical workstation to detect the plating solution added to the test tank in real time and obtain cyclic voltammetry data. The data analysis module is used to analyze the cyclic voltammetry data obtained from the electrochemical detection module to obtain characteristic signal values, and to calculate the current additive concentration in real time based on the characteristic signal values. An automatic replenishment module, including at least one metering pump and at least one additive storage tank, is used to replenish additives to the main electroplating tank. The control module is communicatively connected to the online sampling module, electrochemical detection module, data analysis module, and automatic replenishment module. It is used to automatically activate an alarm or control the metering pump in the automatic replenishment module to add a fixed amount of additive to the main electroplating tank based on the current additive concentration obtained by the data analysis module.

7. The system according to claim 6, characterized in that, The three-level unit includes a working electrode, a counter electrode, and a reference electrode.

8. The system according to claim 6, characterized in that, The three-electrode unit is immersed in the plating solution in the test tank.

9. The system according to claim 6, characterized in that, When the current additive concentration is lower than the preset concentration range, the control module sends a pulse signal to the metering pump, and the metering pump pumps a fixed volume of the additive into the main electroplating tank; if the current additive concentration is higher than the preset concentration range, the control module will automatically activate an alarm.

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