TW202129271A - Method for monitoring copper ion concentration - Google Patents

Abstract

The present invention relates to a monitoring method. The method comprises providing a test solution containing copper ions; providing a monitoring device; measuring a cyclic voltammetry curve of the test solution over a specific voltage interval by the monitoring device, wherein the cyclic voltammetry curve has a peak current; providing a plurality of copper ion standard solutions with various known concentrations of copper ions, measuring cyclic voltammetry curves of the copper ion standard solutions over the specific voltage interval by the monitoring device, wherein each of the cyclic voltammetry curves has its peak current, and determining a linear equation of Y=AX+B by plotting the known concentrations of copper ions versus the peak currents corresponding thereto, wherein Y is the peak current, A is a slope of the linear equation, X is the concentration of copper ions and B is an intercept of the linear equation; and substituting the measured peak current of the test solution into the linear equation to obtain a copper concentration of the test solution.

Description

Copper ion concentration monitoring method

The invention relates to a monitoring method for quantitatively determining the concentration of copper ions by cyclic voltammetry.

In the process of preparing liquid crystal display panels and printed circuit boards, various etching solutions are often used to etch metal materials. The metal ions generated during the etching process will continue to accumulate in the etching solution. When the concentration of the metal ions in the etching solution rises to a certain level, the etching solution will become unusable and become etching waste.

At present, the etching solution system widely used in the industry includes acid copper chloride etching solution and alkaline copper chloride etching solution. The acid copper chloride etching solution uses copper chloride as the copper etching agent, and uses an acid oxidation system to regenerate the copper etching agent. Alkaline copper chloride, copper chloride etching solution used in the complexation reaction with ammonia generated by the cupric ammonia complex Cu (NH _{3) 4} Cl ₂ as the etching agent, copper, and oxygen, NH ⁴⁺ and Cl ^- in the reaction , Carry out the regeneration of the copper etching agent. As the etching progresses, the copper on the board will be bitten to form monovalent copper Cu(NH ₃ ) ₂ Cl. Because the monovalent copper is insoluble in water, the concentration of divalent copper gradually decreases with the biting time. , Causing the etching speed to be affected.

In this field, as manufacturers and industries are different, the etching solution formula used and the tolerable metal ion concentration are not the same. Take the etching solution used by some domestic thin film transistor liquid crystal display (TFT LCD) manufacturers as an example. When the concentration of copper ions in the etching solution reaches about 1000 ppm, the etching solution loses its etching ability. Ability, and must be replaced with a new etching solution. In addition, in the copper etching etching solution used by some printed circuit board (PCB) manufacturers, the tolerable copper ion concentration is about 130 g/L.

The general method for controlling the concentration of alkaline etching solution is to measure pH, hydrometer and temperature, but there is no intuitive method to monitor the concentration of monovalent copper in the measurement solution; in addition, there are also chelating agents (such as EDTA) in the prior art. The chemical reaction is used to chelate copper ions to control the concentration of copper ions (Cu ²⁺ ) in the solution, but because it cannot accurately and quantitatively control the copper concentration, and it has side effects such as pollution of the bath and heat, resulting in the effectiveness of copper control Inappropriate, increased cost and potentially dangerous. In addition, the prior art CN201686754U proposes an automatic control device for copper extraction. However, the automatic control device measures the concentration of copper ions in the waste liquid through the specific gravity method. This method is sensitive to small-volume solutions and low-concentration (ppm) copper ions. Not high, there is still room for improvement.

In view of this, the present invention provides a monitoring system for quantitative determination of copper ion concentration by cyclic voltammetry, which is its main purpose.

For the purpose of the above disclosure, the monitoring method of the present invention includes the following steps: providing a solution to be tested containing copper ions; providing a monitoring device; in a specific potential interval, the monitoring device measures a cycle of the solution to be tested Voltammetry curve, the cyclic voltammetry curve has a peak current value; a complex set of copper ion standard solutions with known concentrations are provided, and the monitoring device measures the cyclic voltammetry curve of the complex set of standard solutions in the specific potential interval. The cyclic voltammetry curve of the concentration standard solution has a peak current value, and a linear equation is determined by the copper ion concentration value of the complex set of standard solution and the peak current value of the corresponding cyclic voltammetry curve. The linear equation is Y=AX +B, where Y represents the peak current value, A represents the slope of the linear equation, X represents the copper ion concentration, and B represents the intercept of the linear equation; take the linear equation and the peak of the cyclic voltammetry curve of the solution to be tested The current value determines the copper ion concentration of the solution to be tested.

In a preferred aspect, the monitoring device has a accommodating slot configured with a first-rate inlet and a first-rate outlet, and a working electrode, an auxiliary electrode, a reference electrode, an ammeter, and a voltmeter are arranged in the accommodating groove. In the accommodating tank, the voltmeter is connected between the working electrode and the reference electrode, and there are also connected power supply units and control units, the power supply unit is electrically connected to the working electrode and the auxiliary electrode, the ampere The meter is connected between the auxiliary electrode and the power supply unit.

In a preferred aspect, the working electrode and the auxiliary electrode may be platinum ring electrodes.

In a preferred aspect, the reference electrode may be a saturated calomel electrode.

In a preferred aspect, the specific potential interval is 0.1 to 0.9 volts.

In a preferred aspect, the monitoring device is arranged in an etching tank to monitor the solution to be tested in the etching tank in a continuous manner.

In a better aspect, the A value in the linear equation is 54.019, and the B value is (-0.4159).

In order to help your examiners understand the technical features, content and advantages of this creation and its achievable effects, this creation is accompanied by drawings and detailed descriptions in the form of embodiments are as follows, and the diagrams used therein are as follows: The subject matter is only for illustrative and auxiliary manual purposes, and may not be the true proportions and precise configuration after the implementation of the creation. Therefore, the scale and configuration relationship of the attached drawings should not be interpreted or limited to the scope of rights of the creation in actual implementation. Hexian stated.

Please refer to Fig. 1 which is a schematic diagram showing the structure of the monitoring device in the present invention. The monitoring device 1 of the present invention at least includes: a containing tank 10, a working electrode 21, an auxiliary electrode 22, a reference electrode 23, a power supply unit 30, a control unit 40, an ammeter 51 and a voltmeter 52; wherein :

The accommodating tank 10 is equipped with a first-rate inlet 11 and a first-rate outlet 12. Please also refer to FIG. The inner side wall surface of the groove 10, and the other end is spaced from the inner side wall surface of the containing groove 10. In the embodiment shown in the figure, three partitions 13 are provided to partition the containing groove 10 into a serpentine donor flow. road.

The working electrode 21, the auxiliary electrode 22, and the reference electrode 23 are arranged in the accommodating groove 10, the working electrode 21 is connected to the reference electrode 23 with a voltmeter 52, and the working electrode 21 and the auxiliary electrode 22 are Partly exposed in the accommodating tank 10 and electrically connected to the power supply unit 30, an ammeter 51 is connected between the power supply unit 30 and the auxiliary electrode 22, and the power supply unit 30 is electrically connected to the control unit 40. The control unit 40 monitors the potential value by the voltmeter 52 under a predetermined voltage, and the current value change by the ammeter 51; wherein, the working electrode 21 and the auxiliary electrode 22 may be platinum ring electrodes, and the reference electrode 23 may be Saturated calomel electrode, and in the embodiment shown in the figure, the working electrode 21 and the auxiliary electrode 22 can be two rings located on the same round rod, and the reference electrode 23 is independently located on the other round rod.

The monitoring method of the preferred embodiment of the present invention is described by taking the measurement of the alkaline etching solution in the etching tank as an example. It specifically includes the following steps: taking an appropriate amount of the solution to be tested containing copper ions in the etching tank and placing it in the containing tank 10. Using the monitoring device 1 to perform cyclic voltammetric scanning on the solution to be tested in the containing tank 10, the specific steps are: placing the working electrode 21, the auxiliary electrode 22 and the reference electrode 23 in the containing tank 10, and In contact with the solution to be tested, set the specific potential interval of the power supply unit 30 to 0.1V~0.9V, turn on the power supply unit 30, scan in the potential interval, and record the potential value of the working electrode 21 and the corresponding current value , The control unit 40 synchronously draws a cyclic voltammetry curve according to the recorded data. In this embodiment, when the potential value of the working electrode 21 is between 0.1 volt and 0.9 volt, a wave crest appears, and the peak current value Ip corresponding to the wave crest is recorded.

A complex set of copper ion standard solutions with known concentrations is configured, where the copper ion concentration of the complex set of standard solutions is different. With the monitoring device 1 under the condition of the potential scanning interval of 0.1V to 0.9V, the above-mentioned voltammetric scanning step is repeated on the plurality of standard solutions respectively, and the peak current values corresponding to the plurality of standard solutions are recorded.

According to the copper ion concentration value of the multiple standard solution and its corresponding peak current value, it can be found that the copper ion concentration value of the multiple standard solution and the peak current value of its cyclic voltammetry curve are in a linear relationship. Therefore, a linear equation can be determined by using the complex number of standard solution concentration values and the corresponding peak current values of the cyclic voltammetry curve. The linear equation is Y=AX+B, where Y represents the peak current value, A represents the slope of the linear equation, X represents the copper ion concentration, and B represents the intercept of the linear equation.

The peak current value of the cyclic voltammetry curve corresponding to the test solution is substituted into the linear equation to determine the copper ion concentration of the test solution.

(註：橫坐標表示五組標準溶液，縱座標表示峰電流值。)In a preferred embodiment of the present invention, the standard solution is prepared in the following manner. Five sealable plastic bottles are each added with 100ml of monovalent copper-free etching solution, and 0.01, 0.05, 0.10, 0.15, 0.20 grams of copper are added respectively. Put the powder into the plastic bottle, and then seal the plastic bottle for 30 minutes to complete five sets of copper ion standard solutions with known concentrations. Repeat the voltammetric scanning steps for the five sets of standard solutions, and record the phases of the five sets of standard solutions. The corresponding peak current values are as follows:

(Note: The abscissa represents five sets of standard solutions, and the ordinate represents the peak current value.)

From the above table, a linear equation can be obtained as Y=54.019X-0.4159, and then the peak current value of the cyclic voltammetry curve corresponding to the solution to be tested is substituted into the Y value in the linear equation to determine the copper of the solution to be tested The ion concentration, that is, the copper ion concentration of the alkaline etching solution in the etching tank can be known.

In addition, the monitoring device of the present invention can be directly configured and installed in a circulation groove of an etching groove, and the flow inlet and outlet are used to form a circulation with the circulation groove, and the solution to be tested in the etching groove is continuously monitored in a continuous manner, and further Cooperate with a photoelectric sensor to calculate the number of plates passing through the etching slot. Not only can the monitoring method of the present invention be used to monitor the concentration of monovalent copper ions in the etching solution, but also the corresponding number of plates can be known by the photoelectric sensor By controlling the production volume of the panels, the addition and regeneration of the alkaline etching solution can also be controlled, and a stable etching speed can be maintained to stabilize the production quality.

The above embodiments are only used to illustrate the present invention, but not to limit the present invention. Various modifications or changes made by those skilled in the relevant fields without departing from the technical scope of the present invention should also fall within the protection scope of the present invention.

1: Monitoring device 10: accommodating slot 11: Inlet 12: Outlet 13: partition 21: working electrode 22: auxiliary electrode 23: Reference electrode 30: power supply unit 40: control unit 51: Ammeter 52: Voltmeter

Figure 1 is a schematic diagram of the structure of the monitoring device in the present invention; and Figure 2 is a three-dimensional view of the structure of the accommodating groove in the present invention.

1: Monitoring device

10: accommodating slot

11: Inlet

12: Outlet

21: working electrode

22: auxiliary electrode

23: Reference electrode

30: power supply unit

40: control unit

51: Ammeter

52: Voltmeter

Claims (8)

A method for monitoring the concentration of copper ions, which includes the following steps: Provide a test solution containing copper ions; Provide a monitoring device; In a specific potential interval, a cyclic voltammetry curve of the solution to be tested is measured by the monitoring device, and the cyclic voltammetry curve has a peak current value; Provide a complex set of copper ion standard solutions with known concentrations, and measure the cyclic voltammetry curve of the complex set of standard solutions by the monitoring device in the specific potential interval. The cyclic voltammetry curve of the standard solution of each concentration has a peak current value, Determine a linear equation with the copper ion concentration value of the complex set of standard solutions and the peak current value of the corresponding cyclic voltammetry curve. The linear equation is Y=AX+B, where Y represents the peak current value, and A represents the peak current value. The slope of the linear equation, X represents the copper ion concentration, and B represents the intercept of the linear equation; and The linear equation and the peak current value of the cyclic voltammetry curve of the test solution are used to determine the copper ion concentration of the test solution. The copper ion concentration monitoring method according to claim 1, wherein the monitoring device has a accommodating tank, the accommodating tank is configured with a first-rate inlet and a first-rate outlet, and has a working electrode, an auxiliary electrode, a reference electrode, and an ampere Considering that a voltmeter is arranged in the accommodating groove, the voltmeter is connected between the working electrode and the reference electrode, and there is a power supply unit and a control unit connected to it, the power supply unit is connected to the working electrode and the auxiliary The electrodes are electrically connected, and the ammeter is connected between the auxiliary electrode and the power supply unit. The copper ion concentration monitoring method according to claim 2, wherein the working electrode and the auxiliary electrode may be platinum ring electrodes. The copper ion concentration monitoring method according to claim 2, wherein the reference electrode may be a saturated calomel electrode. The method for monitoring the concentration of copper ions according to claim 2, wherein at least one partition is further provided in the containing tank. The copper ion concentration monitoring method according to any one of claims 1 to 4, wherein the specific potential interval is 0.1 volts to 0.9 volts. The copper ion concentration monitoring method according to any one of claims 1 to 4, wherein the monitoring device is disposed in an etching tank to continuously monitor the solution to be tested in the etching tank. The copper ion concentration monitoring method according to any one of claims 1 to 4, wherein the value A in the linear equation is 54.019 and the value B is (-0.4159).

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