Method for detecting chloride ions in tetraethoxysilane

Abstract

The invention discloses a method for detecting chloride ions in tetraethoxysilane. The method mainly comprises the following steps: 1) stirring tetraethoxysilane and water in a beaker; 2) mixing the stirred tetraethoxysilane with water to obtain a liquid, and taking out a water layer to obtain an extract A; (3) repeating the step (1) and the step (2) on the extracted ethyl orthosilicate to obtain an extracting solution B; 4) evaporating and extracting the water liquid at high temperature to obtain a to-be-detected liquid; and 5) carrying out ion chromatography detection on the to-be-detected solution. According to the method, chloride ions in tetraethoxysilane are transferred into water, organic substances are effectively removed, and introduction of additional anions is avoided, so that damage to an ion chromatograph and interference to ion chromatography detection are avoided, trace chloride ions in tetraethoxysilane can be accurately detected, the detection precision is high, and operation is simple, convenient and rapid.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of chloride ion detection, and particularly relates to a method for detecting chloride ions in tetraethyl orthosilicate. BACKGROUND

[0002] In the integrated circuit manufacturing process, anions can cause component contamination, resulting in problems such as short circuit and corrosion, thereby affecting product yield and equipment life. With the continuous advancement of integrated circuit manufacturing, this phenomenon is becoming more and more obvious, so the requirements for anions in raw materials are becoming more and more stringent. Tetraethyl orthosilicate is one of the upstream raw materials for integrated circuits, such as a precursor for deposition in semiconductor processes, used for integrated circuit interlayer dielectric and filling material. However, the synthesis process of tetraethyl orthosilicate can introduce chloride ions. At present, there is no standard test method for the content of chloride ions in tetraethyl orthosilicate.

[0003] Common methods for detecting chloride ions include colorimetric method, turbidimetric method, titration method and ion chromatography method. As traditional methods, the colorimetric method, the turbidimetric method and the titration method have problems such as complicated pre-treatment, long operation period and low detection precision, which cannot meet the requirements of trace chloride ion testing. The ion chromatography method for determining the content of chloride ions can meet the requirements of trace chloride ion detection due to its simple operation and high detection precision.

[0004] Ion chromatography is easily contaminated by organic matter and damaged, and tetraethyl orthosilicate as an organosilicon compound cannot directly enter ion chromatography, so the sample pretreatment of tetraethyl orthosilicate is required. The first pretreatment method is hydrolysis method, and the patent CN110646539B discloses a detection method of chlorine ions in electronic-grade tetraethyl orthosilicate. Under heating conditions, tetraethyl orthosilicate is added to a mixed solution of alkaline substance sodium bicarbonate, ethanol and water, and then tetraethyl orthosilicate is hydrolyzed to synthesize silicon dioxide, and then hydrofluoric acid is added to dissolve the silicon dioxide to obtain a to-be-tested solution. Although the problem that tetraethyl orthosilicate cannot enter chromatographic analysis is solved, the addition of sodium bicarbonate and hydrofluoric acid leads to the introduction of chlorine ions and a large amount of fluorine ions, which will interfere with the detection of chlorine ions, and the residual ethanol is not completely removed, which will damage the chromatographic column and cause the problem of steamed bun-shaped tailing peaks, causing large test errors. The second pretreatment method is extraction method, and the patent CN110824033A discloses a method for rapidly detecting chlorine ions in tetraethyl orthosilicate. The tetraethyl orthosilicate is shaken and extracted by a vortex oscillator, and the water layer is taken out after centrifugation. After filtration by a PR column, the to-be-tested sample is obtained. The vortex oscillator is used to extract the chlorine ions in the tetraethyl orthosilicate into water, and the contact surface between the tetraethyl orthosilicate and water is small, which is not conducive to the transfer of chlorine ions to water. In addition, the to-be-tested sample contains ethanol produced by the hydrolysis of tetraethyl orthosilicate, and the ethanol will also damage the chromatographic column and cause the problem of steamed bun-shaped tailing peaks, causing large test errors. In addition, the filtration by the PR column is troublesome, high in cost, and cannot guarantee the avoidance of the introduction of chlorine ions, causing the problem of large chlorine ion test. SUMMARY

[0005] To solve the above technical problems, the technical scheme adopted by the present application is: a detection method of chlorine ions in tetraethyl orthosilicate, comprising: Step 1, a certain amount of tetraethyl orthosilicate is stirred and mixed with a certain amount of water in a container to obtain a mixed solution; Step 2, the mixed solution is extracted and separated by standing, and the lower liquid is taken out from the container to obtain an extraction liquid A; Step 3, a certain amount of water is added to the container and continues to be stirred, and then extracted and separated by standing, and the lower liquid is taken out from the container to obtain an extraction liquid B; Step 4, a to-be-tested solution is prepared by one evaporation method or two evaporation methods. The two evaporation methods include: the extraction liquid A and the extraction liquid B are evaporated at high temperature respectively to obtain a to-be-tested solution A and a to-be-tested solution B. The one evaporation method includes: the extraction liquid A and the extraction liquid B are mixed to obtain an extraction liquid AB, and the extraction liquid AB is evaporated at high temperature to obtain a to-be-tested solution AB; Step 5, the to-be-tested solution A and the to-be-tested solution B are detected by ion chromatography, or the to-be-tested solution AB is detected by ion chromatography, and the content of chlorine ions in the tetraethyl orthosilicate is calculated.

[0006] As the preferred technical scheme of the above, the weight ratio of water and tetraethyl orthosilicate in the mixed solution is 0.1-3:1.

[0007] As the preferred technical scheme of the above, the stirring speed in step 1 is 20-1500 revolutions, the stirring time is 0.1-8 hours, and the stirring temperature is 10-50℃.

[0008] As the preferred technical scheme of the above, the temperature of high-temperature evaporation in step 4 is 100℃.

[0009] As the preferred technical scheme of the above, in step 4, a certain amount of water is added to the to-be-tested liquid A, the to-be-tested liquid B or the to-be-tested liquid AB, or a certain amount of water is added to the extraction liquid A, the extraction liquid B or the extraction liquid AB before high-temperature evaporation, so that the weight of the to-be-tested liquid A before ion chromatography detection is equal to the weight of the extraction liquid A, the weight of the to-be-tested liquid B is equal to the weight of the extraction liquid B, and the weight of the to-be-tested liquid AB is equal to the weight of the extraction liquid AB.

[0010] The content M of chloride ions in tetraethyl orthosilicate is calculated according to the following formula: Two evaporation methods: M=T / W*(Ma+Mb) One evaporation method: M=T / W*Mab Wherein M is the content of chloride ions in tetraethyl orthosilicate, T is the mass of tetraethyl orthosilicate, W is the mass of water, Ma is the content of chloride ions in the to-be-tested liquid A, Mb is the content of chloride ions in the to-be-tested liquid B, and Mab is the content of chloride ions in the to-be-tested liquid AB.

[0011] The beneficial effects of the present application are: the present application transfers chloride ions in tetraethyl orthosilicate to water, effectively removes organic substances and avoids the introduction of additional anions, thereby avoiding damage to the ion chromatograph and interference with ion chromatography detection, enabling accurate detection of trace chloride ions in tetraethyl orthosilicate, high detection accuracy, and simple, convenient and fast operation. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is the ion chromatogram obtained in Example 2 of the present application. DETAILED DESCRIPTION

[0013] The technical solutions of the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0014] Ion chromatography is to introduce the sample dissolved in the mobile phase into the chromatographic column by eluent, and different ion compounds are separated by the difference of interaction between the chromatographic column and the stationary phase, and the ion is detected by the detector, so as to realize the qualitative and quantitative analysis of ion.

[0015] ICS-2000 ion chromatograph is used in the application, Thermo Fisher Scientific (China) Co., Ltd., equipped with sodium carbonate and sodium bicarbonate eluent automatic generating device and conductivity detector. IonPac AS22 anion exchange analytical column (250mmx4mm), IonPac AG22 anion exchange guard column (50mmx4mm), ASRS300 anion electrolytic suppressor, column temperature 30℃. In addition, the eluent is Na2CO3 (4.5mmol / L) and NaHCO3 (1.4mmol / L), the flow rate is 1.0mL / min, and the sample volume is 100µL.

[0016] Adjust the ion chromatograph to the best state, calibrate it according to the operation procedure of ion chromatography to obtain the working curve, and then detect the test solution. According to the peak area of the test sample, the content of chloride ion in the test solution is obtained.

[0017] The content M of chloride ion in tetraethyl orthosilicate is calculated according to the following formula: Two evaporation methods: M=T / W*(Ma+Mb) Single evaporation method: M=T / W*Mab Wherein M is the chloride ion content of tetraethyl orthosilicate, T is the mass of tetraethyl orthosilicate, W is the mass of ultrapure water, Ma is the chloride ion content of test solution A, Mb is the chloride ion content of test solution B, and Mab is the chloride ion content of test solution AB.

[0018] Example 1 (Step 1) Take 50g of tetraethyl orthosilicate and 50g of ultrapure water and add them to a 200ml glass beaker. Start magnetic stirring at 600r / min. Stir for 4 hours at room temperature.

[0019] (Step 2) After stirring, pour into a 200ml separatory funnel and stand for 10 minutes. After the lower liquid is clear and transparent, discharge the extract A from the bottom.

[0020] (Step 3) Pour the upper tetraethyl orthosilicate of the separatory funnel back into the beaker, add 50g of ultrapure water, and repeat the operations of step 1 and step 2 to obtain extract B.

[0021] (Step 4) Take 40g of the extraction liquid A and 40g of ultrapure water and add them to a 200ml beaker. Evaporate at 100°C to 40g and then cool to room temperature to obtain the test liquid A. Take 40g of the extraction water B and 40g of ultrapure water and add them to a 200ml beaker. Evaporate at 100°C to 40g and then cool to room temperature to obtain the test liquid B.

[0022] (Step 5) The test liquids are tested by ion chromatography respectively, and the results are shown in Table 3.

[0023] Example 2 (Step 1) Take six identical tetraethyl orthosilicate, each 50g, add 50g of ultrapure water respectively, and place them in a 200ml glass beaker. Start the magnetic stirring at 600rpm and continue stirring at room temperature for 4 hours.

[0024] (Step 2) After stirring, pour into a 200ml separatory funnel and stand for 10 minutes. After the lower liquid is clear and transparent, discharge the extraction liquid A from the bottom. (Step 3) Pour the upper tetraethyl orthosilicate of the separatory funnel back into the beaker, add 50g of ultrapure water, and repeat the operations of Step 1 and Step 2 to obtain the extraction liquid B.

[0025] (Step 4) Take 40g of the extraction liquid A and 40g of the extraction liquid B respectively and add them to a 200ml beaker. Evaporate at 100°C to 40g and then cool to obtain the test liquid AB.

[0026] (Step 5) The test liquids are tested by ion chromatography respectively, and the results are shown in Table 1 and Table 3. Table 1 In Table 1, the detection results of chloride ions in Example 2 are calculated. The RSD of the chloride ion content of the 6 sets of experimental data is 1.34%, which is less than 2%. This indicates that the method has good repeatability, high detection accuracy, and meets the accuracy requirements for chloride ion detection.

[0027] Example 3 (Step 1) Take three identical tetraethyl orthosilicate, each 50g, add 50g of ultrapure water respectively, and place them in a 200ml glass beaker. Start the magnetic stirring at 600rpm and continue stirring at room temperature for 4 hours.

[0028] (Step 2) After stirring, pour into a 200ml separatory funnel and stand for 10 minutes. After the lower liquid is clear and transparent, discharge the extraction liquid A from the bottom. (Step 3) Pour the upper tetraethyl orthosilicate of the separatory funnel back into the beaker, add 50g of ultrapure water, and repeat the operations of Step 1 and Step 2 to obtain the extraction liquid B.

[0029] (Step 4) Respectively take 40g of the extraction liquid A and 40g of the extraction liquid B into a 200ml beaker, evaporate to 40g at 100℃, and obtain the test liquid AB after cooling.

[0030] (Step 5) Perform ion chromatography test on the test liquid, and obtain the results in Table 2.

[0031] (Step 6) Extract the chloride standard mixed solution and tetraethyl orthosilicate, repeat steps 1-5 respectively, and record the results in Table 2. Table 2 In order to prove the reliability and accuracy of the detection, the standard addition method is adopted. As can be seen from Table 2, by adding different concentrations of chloride ions, the recovery rate of the added chloride ions is close to 100% through comparison of the theoretical value and the measured value. It shows that the method for testing chloride ions has the characteristics of high reliability and accuracy, and meets the requirements of trace chloride ion content detection.

[0032] Comparative Example 1 Take 50g of tetraethyl orthosilicate and 50g of ultrapure water into a 200ml glass beaker, start magnetic stirring at 600r / min, and continuously stir at room temperature for 4 hours. After stirring, pour into a 200ml separatory funnel, and stand for 10 minutes. After the lower liquid is clear and transparent, the extraction liquid A is discharged from the bottom. Perform ion chromatography test on the extraction liquid A, and obtain the results in Table 3.

[0033] Comparative Example 2 Take 50g of tetraethyl orthosilicate and 50g of ultrapure water into a 200ml glass beaker, start magnetic stirring at 600r / min, and continuously stir at room temperature for 5 hours. After stirring, pour into a 200ml separatory funnel, and stand for 10 minutes. After the lower liquid is clear and transparent, the extraction liquid A is discharged from the bottom. Perform ion chromatography test on the extraction liquid A, and obtain the results in Table 3.

[0034] Comparative Example 3 Take 50g of tetraethyl orthosilicate and 50g of ultrapure water into a 200ml glass beaker, start magnetic stirring at 600r / min, and continuously stir at room temperature for 8 hours. After stirring, pour into a 200ml separatory funnel, and stand for 10 minutes. After the lower liquid is clear and transparent, the extraction liquid A is discharged from the bottom. Perform ion chromatography test on the extraction liquid A, and obtain the results in Table 3. Table 3 In the comparative example 1, the comparative example 2 and the comparative example 3, it can be seen from the chloride ion detection result that the longer the extraction time is, the more favorable the chloride ion extraction is, but the longer the time is, the more the hydrolysis of the tetraethyl orthosilicate is, the extraction water is unstable and easy to gel, and the chloride ion test is not favorable. Therefore, in order to extract the chloride ion in the tetraethyl orthosilicate more completely, the chloride ion in the tetraethyl orthosilicate is extracted twice in the embodiment, and it is obtained from the test result of the embodiment 1 that the chloride ion extraction is mainly in the first time, and the second extraction only contains a small amount of chloride ion, which indicates that the chloride ion in the tetraethyl orthosilicate can be completely extracted after two times, and through the comparison of the result in the embodiment 2, the repeatability of the chloride ion result of two times is good, in addition, the organic matter in the extraction liquid is removed by evaporation in the embodiment 1 and the embodiment 2, compared with the comparative example 1, the comparative example 2 and the comparative example 3, the test liquid is stable, and there is no steamed bun peak in the ion chromatography peak, and there is no organic matter in the test liquid to interfere with the chromatography and affect the service life of the ion chromatography. Therefore, through the technical solution, the chloride ion detection precision is high, the repeatability is good, and the ion chromatography is not damaged.

[0035] It can be seen from the chromatography (the specification is attached Figure 1 ) of the embodiment 2 that the chloride ion peak is good, there is no steamed bun peak caused by the organic matter and baseline drift to cause the test error problem, therefore, the test liquid provided by the technical solution has no organic matter to interfere with the ion chromatography test, the test is accurate, is favorable for the service life of the ion chromatography, and the test liquid has no organic matter, the ion chromatography is easier to clean, and the inaccuracy of the ion chromatography test caused by incomplete cleaning is avoided.

[0036] It is worth mentioning that the ion chromatography and other technical features involved in the patent application of the application should be regarded as prior art, the specific structure, working principle and possible control mode and spatial arrangement mode of these technical features can be selected by using the conventional selection in the field, and should not be regarded as the invention point of the patent of the application, and the patent of the application will not be further specifically expanded and described.

[0037] The above describes the preferred embodiment of the application in detail, and it should be understood that those skilled in the art can make many modifications and changes without creative labor according to the concept of the application, therefore, all the technical solutions obtained by logical analysis, reasoning or limited experiments on the basis of the prior art according to the concept of the application should be within the protection scope determined by the claims.

Claims

1. A method for detecting chloride ions in tetraethyl orthosilicate, characterized in that, include: Step 1: Mix a certain amount of tetraethyl orthosilicate and a certain amount of water in a container to obtain a mixture; Step 2: Allow the mixture to stand for extraction and separation, and remove the lower layer liquid from the container to obtain extract A; Step 3: Add a certain amount of water to the container and continue stirring. Then let it stand to extract and separate. Take out the lower layer of liquid from the container to obtain extract B. Step 4: Prepare the test solution using either a single evaporation method or a double evaporation method. The double evaporation method includes: evaporating extract A and extract B separately at high temperature to obtain test solution A and test solution B; the single evaporation method includes: mixing extract A and extract B to obtain extract AB, and evaporating extract AB at high temperature to obtain test solution AB. Step 5: Perform ion chromatography detection on test solution A and test solution B, or perform ion chromatography detection on test solutions AB, and calculate the chloride ion content in tetraethyl orthosilicate.

2. The method for detecting chloride ions in tetraethyl orthosilicate as described in claim 1, characterized in that, The weight ratio of water to tetraethyl orthosilicate in the mixture is 0.1-3:

1.

3. The method for detecting chloride ions in tetraethyl orthosilicate as described in claim 1, characterized in that, In step 1, the stirring speed is 20-1500 rpm, the stirring time is 0.1-8 hours, and the stirring temperature is 10-50℃.

4. The method for detecting chloride ions in tetraethyl orthosilicate as described in claim 1, characterized in that, The temperature for high-temperature evaporation in step 4 is 100℃.

5. The method for detecting chloride ions in tetraethyl orthosilicate as described in claim 1, characterized in that, In step 4, a certain amount of water is added to test solution A, test solution B, or test solution AB, or a certain amount of water is added to extract solution A, extract solution B, or extract solution AB before high-temperature evaporation, so that the weight of test solution A before ion chromatography detection is equal to the weight of extract solution A, the weight of test solution B is equal to the weight of extract solution B, and the weight of test solution AB is equal to the weight of extract solution AB.

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