CN113138215A

CN113138215A - Copper ion concentration monitoring method

Info

Publication number: CN113138215A
Application number: CN202010054568.7A
Authority: CN
Inventors: 郑文锋; 许吉昌; 孙尚培; 许宏玮
Original assignee: Boardtek Electronics Corp
Current assignee: Boardtek Electronics Corp
Priority date: 2020-01-17
Filing date: 2020-01-17
Publication date: 2021-07-20
Anticipated expiration: 2040-01-17
Also published as: CN113138215B

Abstract

The monitoring method comprises the following steps: providing a solution to be detected containing copper ions; providing a monitoring device; in a specific potential interval, measuring a cyclic voltammetry curve of the solution to be measured by the monitoring device, wherein the cyclic voltammetry curve has a peak current value; providing a plurality of sets of copper ion standard solutions with known concentrations, determining cyclic voltammetry curves of the plurality of sets of standard solutions by the monitoring device in the specific potential interval, wherein the cyclic voltammetry curve of each concentration standard solution has a peak current value, and determining a linear equation by using the copper ion concentration values of the plurality of sets of standard solutions and the peak current values of the corresponding cyclic voltammetry curves, wherein the linear equation is Y-AX + B, wherein 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; and determining the copper ion concentration of the solution to be detected according to the linear equation and the peak current value of the cyclic voltammetry curve of the solution to be detected.

Description

Copper ion concentration monitoring method

Technical Field

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

Background

In the process of manufacturing liquid crystal display panels and printed circuit boards, various etching solutions are often used to etch metal materials. The metal ions generated in the etching process are continuously accumulated in the etching solution, and when the concentration of the metal ions in the etching solution is increased to a certain degree, the etching solution can be used to form waste etching solution.

At present, the etching liquid widely used in the industry includes acidic copper chloride etching liquid and alkaline copper chloride etching liquid. The acidic copper chloride etching solution uses copper chloride as a copper etching agent, and uses an acidic oxidation system to regenerate the copper etching agent. The alkaline copper chloride etching solution uses a cupric chloride and ammonia water complex Cu (NH) generated by the complexing reaction of copper chloride and ammonia water₃)₄Cl₂As copper-etching agent, with oxygen, NH⁴⁺And Cl^-And reacting to regenerate the copper etching agent. As the etching proceeds, the copper on the board is etched to form monovalent copper Cu (NH)₃)₂Cl, the monovalent copper is insoluble in water, so that the concentration of the divalent copper gradually decreases with time, resulting in the influence of the etching rate.

In the art, the recipe and tolerable metal ion concentration of the etching solution used vary from manufacturer to industry. Taking the etching solution used by some manufacturers of thin film transistor liquid crystal displays (TFT LCDs) in China as an example, when the concentration of copper ions in the etching solution reaches about 1000ppm, the etching solution loses the etching capability and must be replaced with a new etching solution. In addition, some Printed Circuit Board (PCB) manufacturers utilize copper etching solutions that can tolerate copper ion concentrations of about 130 g/L.

The general method for controlling the concentration of alkaline etching solution is to measure pH, gravimeter and temperature, but there is no intuitive method for monitoringControlling and measuring the concentration of monovalent copper in the solution; in addition, the chemical reaction of chelating agent (such as EDTA) is also used to chelate copper ions in the prior art to control the copper ions (Cu) in the solution²⁺) However, the concentration of copper cannot be accurately and quantitatively controlled, and the copper has side effects of polluting the bath solution, generating heat and the like, so that the control effect of copper is poor, the cost is increased and the copper has potential danger. In addition, CN201686754U in the prior art proposes an automatic control device for copper extraction, which measures the concentration of copper ions in waste liquid by a specific gravity method, and has a low sensitivity to low concentration (ppm) of copper ions in a small volume of solution, and still has room for improvement.

Disclosure of Invention

In view of the above, the present invention provides a monitoring system for quantitatively determining the concentration of copper ions by cyclic voltammetry, which is a main objective thereof.

The technical means adopted by the invention are as follows.

To achieve the above object, the monitoring method of the present invention comprises the steps of: providing a solution to be detected containing copper ions; providing a monitoring device; in a specific potential interval, measuring a cyclic voltammetry curve of the solution to be measured by the monitoring device, wherein the cyclic voltammetry curve has a peak current value; providing a plurality of sets of copper ion standard solutions with known concentrations, determining cyclic voltammetry curves of the plurality of sets of standard solutions by the monitoring device in the specific potential interval, wherein the cyclic voltammetry curve of each concentration standard solution has a peak current value, and determining a linear equation by using the copper ion concentration values of the plurality of sets of standard solutions and the peak current values of the corresponding cyclic voltammetry curves, wherein the linear equation is Y-AX + B, wherein 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; and determining the copper ion concentration of the solution to be detected according to the linear equation and the peak current value of the cyclic voltammetry curve of the solution to be detected.

In a preferred aspect, the monitoring device has a receiving cavity, the receiving cavity is configured with an inlet and an outlet, and has a working electrode, an auxiliary electrode, a reference electrode, an ammeter, and a voltmeter configured in the receiving cavity, the voltmeter is connected between the working electrode and the reference electrode, and further has a power supply unit and a control unit connected thereto, the power supply unit is electrically connected to the working electrode and the auxiliary electrode, and the ammeter is connected between the auxiliary electrode and the power supply unit.

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

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

In a preferred embodiment, the specific potential range is 0.1 to 0.9 volts.

In a preferred aspect, the monitoring device is configured in an etching bath, and the solution to be tested in the etching bath is monitored in a continuous manner.

In a more preferred aspect, the linear equation has an A value of 54.019 and a B value of-0.4159.

Drawings

Fig. 1 is a schematic structural diagram of a monitoring device according to the present invention.

Fig. 2 is a perspective view of the structure of the accommodating groove of the present invention.

FIG. 3 is a linear plot of peak current values corresponding to different standard solutions of the present invention.

Description of the figure numbers:

monitoring device 1

Accommodation groove 10

Inflow opening 11

Outflow opening 12

Partition 13

Working electrode 21

Auxiliary electrode 22

Reference electrode 23

Power supply unit 30

Control unit 40

Ampere meter 51

A voltmeter 52.

Detailed Description

Fig. 1 is a schematic structural diagram of a monitoring device according to the present invention. The monitoring device 1 of the present invention comprises at least: a receiving 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.

As shown in fig. 2, the accommodating groove 10 is further provided with at least one partition plate 13, one end of the partition plate 13 is fixed on the inner side wall surface of the accommodating groove 10, and the other end of the partition plate 13 is spaced from the inner side wall surface of the accommodating groove 10, in the embodiment shown in the figure, three partition plates 13 are provided, so as to partition the accommodating groove 10 into a meandering donor flow channel.

The working electrode 21, the auxiliary electrode 22 and the reference electrode 23 are disposed in the container 10, the working electrode 21 and the reference electrode 23 are connected to a voltmeter 52, the working electrode 21 and the auxiliary electrode 22 are partially exposed in the container 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, the power supply unit 30 is electrically connected to the control unit 40, the control unit 40 monitors a potential value by the voltmeter 52 at a predetermined voltage, and the ammeter 51 monitors a change in a current value; in the embodiment shown in the figure, the working electrode 21 and the auxiliary electrode 22 can be platinum circular ring electrodes, and the reference electrode 23 can be saturated calomel electrodes, and in the embodiment shown in the figure, the working electrode 21 and the auxiliary electrode 22 can be two circular rings respectively located on the same circular rod, and the reference electrode 23 is independently located on the other circular rod.

The monitoring method of the preferred embodiment of the present invention is illustrated by taking the measurement of the alkaline etching solution in the etching tank as an example. The method specifically comprises the following steps: a proper amount of the solution to be measured containing copper ions in the etching tank is placed in the containing tank 10. By means of the monitoring device 1, cyclic voltammetry scanning is carried out on the solution to be measured in the accommodating groove 10, and the specific steps are as follows: the working electrode 21, the auxiliary electrode 22 and the reference electrode 23 are placed in the containing tank 10 and are in contact with the solution to be measured, a specific potential interval of the power supply unit 30 is set to be 0.1-0.9 volts, the power supply unit 30 is started, the power supply unit is circularly scanned in the potential interval, the potential value of the working electrode 21 and the current value corresponding to the potential value are recorded, and 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 peak appears, and the peak current value Ip corresponding to the peak is recorded.

Preparing a plurality of sets of standard solutions of copper ions with known concentrations, wherein the concentrations of the copper ions of the plurality of sets of standard solutions are different. And respectively repeating the volt-ampere scanning steps on the plurality of groups of standard solutions under the condition of a potential scanning interval of 0.1-0.9 volt by using the monitoring device 1, and recording the peak current values corresponding to the plurality of groups of standard solutions.

According to the copper ion concentration values of the plurality of groups of standard solutions and the corresponding peak current values thereof, it can be found that the copper ion concentration values of the plurality of groups of standard solutions and the peak current values of the cyclic voltammetry curves form a linear relationship. Therefore, a linear equation can be determined from the plurality of sets of values of the concentration of the standard solution and the peak current value of the corresponding cyclic voltammogram. 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.

And substituting the peak current value of the cyclic voltammetry curve corresponding to the solution to be detected into the linear equation so as to determine the copper ion concentration of the solution to be detected.

In the preferred embodiment of the present invention, the standard solution is prepared by adding 100ml of non-valent copper etching solution into five sealable plastic bottles, respectively, adding 0.01, 0.05, 0.10, 0.15, 0.20 g of copper powder into the plastic bottles, respectively, sealing the plastic bottles for 30 minutes, completing five groups of copper ion standard solutions with known concentrations, repeating the above voltammetry scanning steps on the five groups of standard solutions, and recording the peak current values corresponding to the five groups of standard solutions as shown in fig. 3. (Note: the abscissa represents five sets of standard solutions and the ordinate represents the peak current value.)

From fig. 3, a linear equation Y is obtained as 54.019X-0.4159, and the peak current value of the cyclic voltammogram corresponding to the solution to be tested is substituted into the Y value in the linear equation to determine the copper ion concentration of the solution to be tested, i.e. the copper ion concentration of the alkaline etching solution in the etching chamber can be obtained.

In addition, the monitoring device of the invention can be directly configured and installed in a circulation groove of an etching bath, and the inflow port and the outflow port are utilized to form circulation with the circulation groove, so as to carry out real-time monitoring on the solution to be measured in the etching bath in a continuous mode, and further, a photoelectric sensor is matched to calculate the number of plates passing through the etching bath.

Claims

1. A copper ion concentration monitoring method is characterized by comprising the following steps:

providing a solution to be detected containing copper ions;

providing a monitoring device;

in a specific potential interval, measuring a cyclic voltammetry curve of the solution to be measured by the monitoring device, wherein the cyclic voltammetry curve has a peak current value;

providing a plurality of sets of copper ion standard solutions with known concentrations, determining cyclic voltammetry curves of the plurality of sets of standard solutions by the monitoring device in the specific potential interval, wherein the cyclic voltammetry curve of each concentration standard solution has a peak current value, and determining a linear equation by using the copper ion concentration values of the plurality of sets of standard solutions and the peak current values of the corresponding cyclic voltammetry curves, wherein the linear equation is Y-AX + B, wherein 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; and

and determining the copper ion concentration of the solution to be detected according to the linear equation and the peak current value of the cyclic voltammetry curve of the solution to be detected.

2. The method as claimed in claim 1, wherein the monitoring device has a receiving chamber, the receiving chamber has an inlet and an outlet, and a working electrode, an auxiliary electrode, a reference electrode, an ammeter and a voltmeter are disposed in the receiving chamber, the voltmeter is connected between the working electrode and the reference electrode, and further has a power supply unit and a control unit connected thereto, the power supply unit is electrically connected to the working electrode and the auxiliary electrode, and the ammeter is connected between the auxiliary electrode and the power supply unit.

3. The method of claim 2, wherein the working electrode and the auxiliary electrode are platinum ring electrodes.

4. The method of claim 2, wherein the reference electrode is a saturated calomel electrode.

5. The method according to claim 2, wherein at least one partition is disposed in the receiving tank.

6. The method for monitoring the concentration of copper ions according to any one of claims 1 to 4, wherein the specific potential range is 0.1V to 0.9V.

7. The method according to any one of claims 1 to 4, wherein the monitoring device is disposed in an etching chamber, and the solution to be measured in the etching chamber is monitored in a continuous manner.

8. The method as claimed in any one of claims 1 to 4, wherein the linear equation has an A value of 54.019 and a B value of-0.4159.