Determination method of impurity elements in hafnium oxide

Abstract

The invention relates to the technical field of impurity detection, and discloses a method for determining impurity elements in hafnium oxide, which comprises the following steps: S1, preparing a hafnium oxide sample solution to be detected; s2, establishing a standard curve of each impurity element to be detected; s3, determining the detection precision of the instrument; s4, verifying the accuracy of the test result and the stability of the test method; and S5, respectively calculating the concentration of each impurity element to be detected in the hafnium oxide sample according to the signal intensity of each impurity element to be detected and the corresponding standard curve. According to the technical scheme, the defects of the existing detection technology in the aspect of detection of impurity elements B, P and U in hafnium oxide can be overcome, and high-accuracy detection of the impurity elements B, P and U in hafnium oxide is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of impurity detection, and in particular to a method for determining impurity elements in hafnium oxide. Background Art

[0002] Hafnium dioxide (HfO2) is an important inorganic substance with unique physical and chemical properties. It is a white solid at room temperature and pressure, insoluble in water, insoluble in hydrochloric acid and nitric acid, and only soluble in concentrated sulfuric acid and hydrofluoric acid. It has three crystal structures: monoclinic, tetragonal and cubic.

[0003] However, due to the characteristics of hafnium oxide as a sparingly soluble oxide, there are many difficulties in detecting its impurity elements. On the one hand, the accuracy of detection is difficult to guarantee, and conventional detection methods are difficult to accurately determine the content of impurity elements. Taking the inductively coupled plasma optical emission spectrometer (ICP-OES) commonly used on the market as an example, when detecting ppb-level impurity elements, its technical defects are exposed for specific elements such as boron (B), phosphorus (P), and uranium (U). These elements have weak detection signals and are easily interfered with at low concentrations, resulting in large deviations in the detection results. On the other hand, the serious matrix interference generated by the hafnium element itself increases the complexity of detection. During the detection process, matrix interference will mask the characteristic signals of impurity elements, making it impossible to directly and accurately perform quantitative analysis in low-concentration areas. This fully demonstrates that traditional detection methods are difficult to meet the needs of accurate determination of trace impurity elements in hafnium oxide, especially when detecting special elements such as B, P, and U. This limitation is particularly prominent.

[0004] In the context of the rapid development of today's high-tech industry, such as semiconductor manufacturing, aerospace and other fields, the purity of hafnium oxide materials has been increasingly demanded. Given that traditional detection methods can no longer meet the high-precision detection needs of key impurity elements such as B, P, and U, it is urgent to develop a method specifically for the determination of B, P, and U impurity elements in hafnium oxide. Summary of the invention

[0005] The present invention aims to provide a method for determining impurity elements in hafnium oxide, so as to overcome the defects of the existing detection technology in detecting B, P and U impurity elements in hafnium oxide and realize high-accuracy detection of B, P and U impurity elements in hafnium oxide.

[0006] To achieve the above object, the present invention adopts the following technical solution: A method for determining impurity elements in hafnium oxide comprises the following steps:

[0007] S1: preparing hafnium oxide sample test solution;

[0008] S2: Establishing the standard curve of each impurity element to be measured;

[0009] S3: Determine the detection accuracy of the instrument;

[0010] S4: Verify the accuracy of test results and the stability of test methods;

[0011] S5: Calculate the concentration of each impurity element to be detected in the hafnium oxide sample according to the signal intensity of each impurity element to be detected and the corresponding standard curve.

[0012] Preferably, in S1, the preparation method of the hafnium oxide sample test solution is: weigh a certain amount of hafnium oxide sample, add 49% hydrofluoric acid to the sample, then heat until the sample is completely dissolved, and finally make up the volume with ultrapure water to ensure that the hafnium content in the prepared hafnium oxide sample test solution is 1000ppm.

[0013] Preferably, in S2, establishing a standard curve for each impurity element to be detected comprises the following steps:

[0014] S2.1: preparing test solutions of different preset concentrations; using the No. 1 storage solution as a matrix, adding test standard solutions of different preset concentrations thereto, thereby obtaining test solutions of different preset concentrations, wherein the No. 1 storage solution is a pure hafnium metal solution with a concentration of 1 g / L;

[0015] S2.2: Determine the isotopes of each impurity element to be measured in hafnium oxide;

[0016] S2.3: Determine the internal standard;

[0017] S2.4: Testing the signal intensity corresponding to each impurity element to be measured at each preset concentration by an inductively coupled plasma mass spectrometer;

[0018] S2.5: Perform linear fitting on each standard point to obtain the corresponding standard curve of each impurity element to be measured.

[0019] Preferably, the test standard solution is a mixed solution composed of three elements: boron, uranium and phosphorus, and the concentrations of boron, uranium and phosphorus are all 1000 ppm.

[0020] Preferably, the isotopes of the impurity elements to be detected in hafnium oxide are 11B, 238U, and 31P.

[0021] Preferably, in S3, the process of determining the detection accuracy of the instrument is: using a storage solution No. 1 with a concentration of 1 g / L as the matrix, and not adding the test standard solution to prepare a blank sample, and using this blank sample to conduct a three-day non-continuous test to determine the detection limit of the instrument method.

[0022] Preferably, in S4, verifying the accuracy of the test results and the stability of the test method comprises the following steps:

[0023] S4.1: Prepare verification standard solution; use B single standard solution, U single standard solution, and P single standard solution to prepare verification standard solution;

[0024] S4.2: Prepare verification sample solution; use pure hafnium metal No. 2 storage solution as the matrix, add a certain amount of verification standard solution and 37% hydrochloric acid, use ultrapure water to make up the volume, shake well, in the verification sample solution, the concentration of P is 10ppb, the concentrations of B and U are both 5ppm, and the concentration of pure hafnium metal No. 2 storage solution is 1g / L;

[0025] S4.3: Verify the corresponding signal intensity of each impurity element to be tested in the sample solution by inductively coupled plasma mass spectrometry, and conduct discontinuous testing for three days;

[0026] S4.4: Substitute the signal intensity corresponding to each impurity element to be tested into the standard curve of the corresponding impurity element, calculate the concentration of the impurity element in the verification sample solution, and compare it with the actual prepared concentration to verify the accuracy of the content of B, P, and U elements in the hafnium-based verification sample solution;

[0027] S4.5: Based on the calculated concentration of the impurity element in the verification sample solution, calculate the relative standard deviation of each element to be tested to determine the fluctuation of the concentration of each impurity element to be tested, so as to determine the stability of the test method.

[0028] Preferably, in S2.3, 9Be and 103Rh are selected as internal standards, and the internal standard slope is 80%-120%.

[0029] Preferably, before testing the signal intensity corresponding to each impurity element to be measured at each preset concentration by using an inductively coupled plasma mass spectrometer, the instrument is tuned first, and a hafnium-based tuning solution is prepared using Tune A standard solution. The prepared hafnium-based tuning solution is placed in the injection tube of the inductively coupled plasma mass spectrometer, and the intensity values ​​of Li, Co, In, and U are observed to meet the requirements.

[0030] Preferably, it also includes S6, sample test effect verification;

[0031] S6.1: Verify the test results of the impurity elements to be tested in the pure hafnium metal storage solution;

[0032] S6.2: Verify the test results of the impurity elements to be tested in the hafnium oxide sample.

[0033] Compared with the prior art, the beneficial effects of this solution are:

[0034] (1) Quantification: 49% hydrofluoric acid is used to dissolve the sample. In this process, the amount of hafnium oxide sample is accurately quantified to match the concentration of 1 gram of hafnium (1 g / L) to ensure the consistency of the sample.

[0035] (2) Pure hafnium alloy is added to the standard curve as a matrix, hafnium oxide is converted into hafnium alloy (1g / L) of the same concentration, and matrix matching is performed to eliminate matrix interference and reduce experimental deviation. The matrix matching technology effectively overcomes the matrix effect, making the standard curve more similar to the sample test environment, thereby improving the accuracy of quantitative analysis of impurity elements, especially in the test of complex matrix samples.

[0036] (3) Design a low-concentration standard curve with 5 standard points, including 0ppb, 1ppb, 2ppb, 5ppb, and 20ppb. Refer to GB / T22554-2010 for details. The concentration range of the standard curve should cover the measurement range of the elements in the sample. Use the sample dilution ratio of 1:1000 to extend its test range and reduce the interference of the sample oxide matrix. Reasonable standard curve concentration point design and appropriate dilution ratio can not only ensure the accurate detection of low-concentration impurity elements, but also perform quantitative analysis in a wider concentration range. At the same time, it reduces the influence of matrix interference on the test results and improves the applicability and accuracy of the test method.

[0037] (4) Determine the isotope selection of impurity elements B, P, and U in hafnium oxide and conduct accurate qualitative and quantitative tests. The selection of specific isotopes helps to accurately identify and quantify target impurity elements in complex sample matrices, avoids interference from other isotopes or isobars, and improves the selectivity and sensitivity of the test.

[0038] (5) By adding specific Be and Rh internal standard elements, the deviation caused by sample testing can be further corrected, and the impurity element analysis in the sample can be accurately performed qualitatively and quantitatively. The application of the internal standard method effectively compensates for the errors caused by factors such as sample handling, injection process, and instrument fluctuations, making the test results more reliable and accurate, especially in long-term or large-volume sample testing, which can significantly improve the stability and repeatability of the test data.

[0039] (6) By preparing a 10 ppb tuning solution Tune A with a 1000 ppm hafnium matrix, the intensity values ​​of Li, Co, In, and U were observed to ensure the stability of the instrument's detection state. The instrument tuning step ensures that the instrument is in the best working state before testing, improves the accuracy and repeatability of the test data, reduces the test error caused by instrument performance fluctuations, and provides reliable hardware support for the entire test process.

[0040] (7) This technical solution demonstrates excellent detection performance, with the lower limit of detection of boron (B) being accurate to 0.14 ppb, the lower limit of detection of phosphorus (P) being accurate to 2.17 ppb, and the lower limit of detection of uranium (U) being 0.14 ppb. Such a low detection limit has significant advantages over traditional detection methods, and can very sensitively capture trace amounts of boron, phosphorus, and uranium elements in samples, greatly broadening the concentration range of impurity element detection in hafnium oxide, and effectively detecting trace impurities that were previously difficult to detect, providing more reliable quality assurance for the application of hafnium oxide materials in fields with extremely high purity requirements such as semiconductor manufacturing and aerospace. In the semiconductor production process, even extremely small amounts of boron, phosphorus, and uranium impurities may have a significant impact on the performance and reliability of semiconductor devices. The high-precision detection capability of this technical solution can accurately control the purity of hafnium oxide materials to ensure that they meet the strict quality standards of related industries. It has effectively promoted the technological progress and product quality improvement of related high-tech industries, significantly reduced the risk of product defects caused by excessive impurity element content, and improved production efficiency and economic benefits.

[0041] (8) Using the verification standard solution prepared from the known concentrations of B single standard solution, U single standard solution, and P single standard solution, combined with the verification sample solution prepared from the pure hafnium metal No. 2 storage solution and 37% hydrochloric acid, reverse verification operation was carried out, and the accuracy was strictly evaluated by comparing the actual concentrations of B, P, and U elements in the hafnium-based verification sample solution with the test concentrations. At the same time, the fluctuation of the concentration of each impurity element to be tested was deeply analyzed, and the stability and reliability of the detection method provided by this technical solution in the actual application process were rigorously judged according to the magnitude of the fluctuation, so as to provide solid data support and scientific basis for the effective application of the detection method in related fields, ensuring that it can accurately and stably detect the content of impurity elements in hafnium oxide, and meet the stringent requirements of scientific research, production and other aspects for detection accuracy and reliability.

[0042] (9) This technical solution further fully verified the wide adaptability of the detection method by conducting spiked recovery tests on pure hafnium alloy storage solution and hafnium oxide test solution. It can be used not only for the determination of impurity elements in hafnium oxide, but also for the determination of impurity elements in pure hafnium alloys, providing effective detection ideas and basis for subsequent hafnium-related sample testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A standard curve of the B impurity element provided in an embodiment of the present invention;

[0044] Figure 2 A standard curve of the P impurity element provided in an embodiment of the present invention;

[0045] Figure 3A standard curve of U impurity element provided in an embodiment of the present invention;

[0046] Figure 4 This is a box plot of the results of verifying the B impurity element in the sample solution in the embodiment of the present invention;

[0047] Figure 5 This is a box plot of the results of verifying the P impurity element in the sample solution in the embodiment of the present invention;

[0048] Figure 6 This is a box plot of the results of verifying the U impurity element in the sample solution in the embodiment of the present invention. DETAILED DESCRIPTION

[0049] The following is further described in detail through specific implementation methods:

[0050] Example

[0051] The method for determining impurity elements in hafnium oxide comprises the following steps:

[0052] S1: Prepare a hafnium oxide sample test solution; specifically, weigh 1.18g of hafnium oxide sample, add 10mL of 49% hydrofluoric acid to the sample, then heat until the sample is completely dissolved, the heating temperature is 200°C, and finally use ultrapure water to make the volume to 1000ml to ensure that the hafnium content in the prepared hafnium oxide sample test solution is 1000ppm.

[0053] S2: Establishing the standard curve of each impurity element to be measured;

[0054] S2.1: Prepare test solutions with different preset concentrations; use storage solution No. 1 as a matrix, add test standard solutions with different preset concentrations to it, so as to obtain test solutions with different preset concentrations; the preset concentrations are 0ppb, 1ppb, 2ppb, 5ppb, and 20ppb; storage solution No. 1 is a pure hafnium metal solution with a concentration of 1g / L, and the test standard solution is a mixed solution composed of three elements: boron, uranium, and phosphorus, and the concentrations of boron, uranium, and phosphorus are all 1000ppm. In this embodiment, storage solution No. 1 is a 4915 storage solution purchased from Westinghouse Electric Company of the United States; the manufacturer of mixed standard solution No. 1 is Inorganic Ventures Reagent Company; specifically:

[0055] Preparation of test solution with a preset concentration of 0 ppb:

[0056] Measure 1.25mL of 80g / L 4915 storage solution, add 2.5mL of 37% hydrochloric acid, then make the solution volume to 100mL with ultrapure water, and finally shake well to mix the solution evenly; the purpose of adding 37% hydrochloric acid is to increase the acidity of the test solution.

[0057] Preparation of test solution with a preset concentration of 1 ppb:

[0058] Take 1.25mL of 80g / L 4915 stock solution, add 0.1mL of 1ppm mixed standard solution No. 1, then add 2.5mL of 37% hydrochloric acid, then make up the volume of the solution to 100mL with ultrapure water, and finally shake well to mix the solution evenly.

[0059] Preparation of test solution with a preset concentration of 2ppb:

[0060] Take 1.25mL of 80g / L 4915 stock solution, add 0.2mL of 1ppm No. 1 mixed standard solution, then add 2.5mL of 37% hydrochloric acid, then use ultrapure water to make the solution volume to 100mL, and finally shake well to mix the solution evenly.

[0061] Preparation of test solution with a preset concentration of 5 ppb:

[0062] Take 1.25mL of 80g / L 4915 stock solution, add 0.5mL of 1ppm mixed standard solution No. 1, then add 2.5mL of 37% hydrochloric acid, then make up the volume of the solution to 100mL with ultrapure water, and finally shake well to mix the solution evenly.

[0063] The preparation method of the test solution with a preset concentration of 20ppb is:

[0064] Take 1.25mL of 80g / L 4915 stock solution, add 2mL of 1ppm No. 1 mixed standard solution, then add 2.5mL of 37% hydrochloric acid, then use ultrapure water to make the solution volume 100mL, and finally shake well to mix the solution evenly.

[0065] It should be noted that, in order to improve the preparation efficiency, a 4915 storage solution with a concentration of 80 g / L is first prepared, and then diluted when used so that the concentration of pure hafnium metal in the system is 1 g / L.

[0066] S2.2: Determine the isotopes of the impurity elements to be measured in hafnium oxide, the isotopes are 11B, 238U, and 31P;

[0067] S2.3: Determine the internal standard, select 9Be and 103Rh as the internal standard, set the working internal standard matching concentration to 200ppbBe / 10ppbRh, and the internal standard slope to 80%-120%; in this embodiment, the manufacturer of the Be single standard and Rh single standard standard solutions is Inorganic Ventures Reagent Company;

[0068] S2.4: Testing the signal intensity corresponding to each impurity element to be tested at each preset concentration by an inductively coupled plasma mass spectrometer (ICP-MS); specifically, firstly, the test solution and the internal standard are fully mixed, and then the mixed solution is placed in the injection tube of the inductively coupled plasma mass spectrometer, and then the signal intensity corresponding to each impurity element to be tested is tested;

[0069] Before the test, the instrument was tuned first, and a hafnium-based tuning solution was prepared using Tune A standard solution, wherein the concentrations of Ba, Be, Bi, Co, In, Li, Pb, and U in the Tune A standard solution were all 10 mg / L, the concentration of the hafnium-based tuning solution was 10 ppb, and the manufacturer of the TUNEA standard solution was Thermo Corporation; the preparation method of the hafnium-based tuning solution was: take 0.25 mL of the TuneA standard solution with a concentration of 10 mg / L, and mix it thoroughly with 3.125 mL of the 4915 storage solution with a concentration of 80 g / L, then add ultrapure water to make up to 250 mL, and shake well; in this embodiment, the manufacturer of the Tune A standard solution is Thermo Fisher Scientific.

[0070] The test process is: put the prepared hafnium-based tuning solution into the injection tube of the inductively coupled plasma mass spectrometer, observe the intensity values ​​of Li, Co, In, and U, and the intensity count values ​​and other parameters should meet the requirements in Table 1.

[0071] Table 1

[0072] Main parameters Standard value Lithium sensitivity ≥10000cps Cobalt sensitivity ≥30000cps Indium sensitivity ≥100000cps Uranium sensitivity ≥100000cps Resolution 0.75±0.1amu CeO / Ce ≤2％ Ba++ / Ba ≤3％ Argon pressure 0.6MPa Pump speed 15-19rpm Injection system Hydrofluoric acid resistant injection system

[0073] S2.5: Perform linear fitting on each standard point to obtain the corresponding standard curve of each impurity element to be measured; construct a standard curve for each impurity element to be measured based on different preset concentrations and the signal intensity corresponding to the impurity element to be measured at each preset concentration. The horizontal axis represents the concentration of the impurity element to be measured, the vertical axis represents the signal intensity of the impurity element to be measured, and the correlation coefficient R of the linear fitting is required. 2 Not less than 0.996, Figure 1-3 They are the standard curves of impurity elements 11B, 31P, and 238U respectively;

[0074] S3: Determine the detection accuracy of the instrument; the specific operation is as follows: Use 4915 storage solution with a concentration of 1g / L as the matrix, and do not add the test standard solution to prepare a blank sample. Use this blank sample to conduct a three-day non-continuous test to determine the detection limit of the instrument method.

[0075] According to the detection limit MDL=S*t(n-1,0.99) in the "US SW-846 Environmental Monitoring Method", when the number of measurements in a single day n=7, the t value is 3.14, S is the standard deviation, and the detection limit can be obtained from 21 sets of data for three non-consecutive days. The detection limit of boron (B) is 0.14ppb, the detection limit of phosphorus (P) is 2.17ppb, and the detection limit of uranium (U) is 0.14ppb.

[0076] S4: Verify the accuracy of test results and the stability of test methods;

[0077] S4.1: Prepare verification standard solution; measure 0.25mL of 100μg / mL boron (B) single standard solution, 2.5mL of 10μg / mL uranium (U) single standard solution, and 0.05mL of 1000μg / mL phosphorus (P) single standard solution respectively, and place them in the same volumetric flask, then add ultrapure water to make up the volume until the total volume of the solution reaches 50mL, and shake well; in this verification standard solution, the concentration of phosphorus (P) is 1ppm, and the concentrations of boron (B) and uranium (U) are both 0.5ppm; the manufacturers of boron (B) single standard solution, uranium (U) single standard solution, and phosphorus (P) single standard solution are all Inorganic Ventures Reagent Company;

[0078] S4.2: Prepare the verification sample solution; measure 1.25mL of 80g / L pure hafnium metal No. 2 storage solution and 1mL of verification standard solution, and then add 2.5mL of 37% hydrochloric acid. Next, add ultrapure water to it to make up the volume until the total volume of the solution reaches 100mL, and finally shake it thoroughly. In the verification sample solution, the concentration of phosphorus (P) is 10ppb, and the concentrations of boron (B) and uranium (U) are both 5ppm. It should be noted that after the 80g / L storage solution No. 2 is diluted to a fixed volume with ultrapure water, its concentration becomes 1g / L. In this embodiment, the No. 2 storage solution is the 7417 storage solution purchased from Westinghouse Electric Company of the United States;

[0079] Testing process: The signal intensity corresponding to each impurity element in the verification sample solution was tested using an inductively coupled plasma mass spectrometer (ICP-MS) for three days of discontinuous testing to verify the accuracy of the B, P, and U element contents in the hafnium-based verification sample solution. Under the condition of a dilution factor of 1000 times, the test results and the control limit of the verification sample solution ((blank sample + spiked sample) ±10%) are shown in Table 2 below:

[0080] Table 2

[0081] element Average value (ppb) Standard Deviation RSD(%) Upper limit (ppb) Lower limit (ppb) B 5.29 0.13 2.46 5.50 4.50 P 10.15 0.50 4.93 11.00 9.00 U 4.98 0.20 4.02 5.50 4.50

[0082] Figure 4-6This is a box plot of the results of 3-day discontinuous testing to verify the impurity elements B, P, and U in the sample solution. The horizontal axis represents the test time, and the vertical axis represents the detection concentration of the impurity elements.

[0083] In the verification sample solution, the actual concentration of phosphorus (P) is 10ppb, and the actual concentrations of boron (B) and uranium (U) are 5ppm. The signal intensity of the impurity elements boron (B), uranium (U), and phosphorus (P) in the verification sample solution is tested using an inductively coupled plasma mass spectrometer. The signal intensity corresponding to each impurity element to be tested in the tested verification sample solution is substituted into the standard curve of the corresponding impurity element, and then the concentration of the impurity element in the verification sample solution is calculated (as shown in Table 2 and Figure 4-6 The concentrations of B, P and U in the hafnium-based verification solution were finally compared with the actual prepared concentrations to verify the accuracy of the content.

[0084] By calculating the relative standard deviation of each element to be tested, the fluctuation of the concentration of each impurity element to be tested is determined, and the stability of the test method is determined. As shown in Table 2, the relative standard deviation of the impurity element boron (B) in the verification sample solution is 2.46%, the relative standard deviation of uranium (U) is 4.02%, and the relative standard deviation of phosphorus (P) is 4.93%. It can be seen that the fluctuation of the impurity elements boron (B), uranium (U), and phosphorus (P) in the verification sample solution is relatively small, and the test method is relatively stable.

[0085] S5: Calculate the concentration of each impurity element to be detected in the hafnium oxide sample according to the signal intensity of each impurity element to be detected and the corresponding standard curve.

[0086] S6: Sample test results verification

[0087] S6.1: Verify the test effect of the impurity elements to be tested in the pure hafnium metal storage solution; use the pure hafnium metal storage solution No. 2 with a concentration of 1g / L as the matrix, test the blank solution and the solutions with different concentrations of B, P, and U standard substances added, test 7 times a day, and test for three consecutive days. Take the average value of 21 groups of data as the sample result, and calculate the spike recovery rate, as shown in Table 3. In this embodiment, the manufacturer of the pure hafnium metal storage solution No. 2 is Westinghouse Electric Corporation of the United States.

[0088] S6.2: Verify the test effect of the impurity elements to be tested in the hafnium oxide sample; use the hafnium oxide sample test solution prepared in S1 as the matrix, and test the solutions with different concentrations of B, P, and U standard substances added. Test 7 times a day for three non-consecutive days, take the average value of 21 groups of data as the sample result, and calculate the spike recovery rate, as shown in Table 3.

[0089] Table 3

[0090]

[0091]

[0092] It should be noted that there are cases where the blank value is negative in Table 3. When the blank value is negative, it means that when the concentration is lower than the detection limit, it is impossible to determine whether the analyte is actually present in the sample. In other words, there is currently no analytical method that can conclusively prove that the substance is absolutely absent in the sample. It is just that when testing according to this standard curve, the substance cannot be effectively detected, but the instrument can give a calculated test value based on the curve, and this test value may be negative.

[0093] The validity of the instrument and method is verified by calculating the recovery rate of the above two samples. From the above spiked test results, it can be seen that the recovery rate is between 95% and 105%, proving that the instrument and method are truly effective in detecting B, P, and U elements in hafnium oxide. In addition, this method also has high accuracy at a lower detection precision.

[0094] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for determining impurity elements in hafnium oxide, characterized in that: The following steps are involved: S1: preparing hafnium oxide sample test solution; S2: Establishing the standard curve of each impurity element to be measured; S3: Determine the detection accuracy of the instrument; S4: Verify the accuracy of test results and the stability of test methods; S5: Calculate the concentration of each impurity element to be detected in the hafnium oxide sample according to the signal intensity of each impurity element to be detected and the corresponding standard curve.

2. The method for determining impurity elements in hafnium oxide according to claim 1, characterized in that: In S1, the preparation method of the hafnium oxide sample test solution is: weigh a certain amount of hafnium oxide sample, add 49% hydrofluoric acid to the sample, then heat until the sample is completely dissolved, and finally use ultrapure water to make up the volume to ensure that the hafnium content in the prepared hafnium oxide sample test solution is 1000ppm.

3. The method for determining impurity elements in hafnium oxide according to claim 2, characterized in that: In S2, a standard curve for each impurity element to be measured is established, comprising the following steps: S2.1: preparing test solutions of different preset concentrations; using the No. 1 storage solution as a matrix, adding test standard solutions of different preset concentrations thereto, thereby obtaining test solutions of different preset concentrations, wherein the No. 1 storage solution is a pure hafnium metal solution with a concentration of 1 g / L; S2.2: Determine the isotopes of each impurity element to be measured in hafnium oxide; S2.3: Determine the internal standard; S2.4: Testing the signal intensity corresponding to each impurity element to be measured at each preset concentration by an inductively coupled plasma mass spectrometer; S2.5: Perform linear fitting on each standard point to obtain the corresponding standard curve of each impurity element to be measured.

4. The method for determining impurity elements in hafnium oxide according to claim 3, characterized in that: The test standard solution is a mixed solution composed of three elements: boron, uranium and phosphorus, and the concentrations of boron, uranium and phosphorus are all 1000ppm.

5. The method for determining impurity elements in hafnium oxide according to claim 4, characterized in that: The isotopes of the impurity elements to be measured in hafnium oxide are 11B, 238U, and 31P.

6. The method for determining impurity elements in hafnium oxide according to claim 5, characterized in that: In S3, the process of determining the detection accuracy of the instrument is as follows: a storage solution No. 1 with a concentration of 1 g / L is used as the matrix, and a blank sample is prepared without adding a test standard solution. This blank sample is used to conduct a three-day non-continuous test to determine the detection limit of the instrument method.

7. The method for determining impurity elements in hafnium oxide according to claim 6, characterized in that: In S4, the accuracy of the test results and the stability of the test method are verified, including the following steps: S4.1: Prepare verification standard solution; use B single standard solution, U single standard solution, and P single standard solution to prepare verification standard solution; S4.2: Prepare verification sample solution; use pure hafnium metal No. 2 storage solution as the matrix, add a certain amount of verification standard solution and 37% hydrochloric acid, use ultrapure water to make up the volume, shake well, in the verification sample solution, the concentration of P is 10ppb, the concentrations of B and U are both 5ppm, and the concentration of pure hafnium metal No. 2 storage solution is 1g / L; S4.3: Verify the corresponding signal intensity of each impurity element to be tested in the sample solution by inductively coupled plasma mass spectrometry, and conduct discontinuous testing for three days; S4.4: Substitute the signal intensity corresponding to each impurity element to be tested into the standard curve of the corresponding impurity element, calculate the concentration of the impurity element in the verification sample solution, and compare it with the actual prepared concentration to verify the accuracy of the content of B, P, and U elements in the hafnium-based verification sample solution; S4.5: Based on the calculated concentration of the impurity element in the verification sample solution, calculate the relative standard deviation of each element to be tested to determine the fluctuation of the concentration of each impurity element to be tested, so as to determine the stability of the test method.

8. The method for determining impurity elements in hafnium oxide according to claim 7, characterized in that: In S2.3, 9Be and 103Rh were selected as internal standards, and the internal standard slope was 80%-120%.

9. The method for determining impurity elements in hafnium oxide according to claim 8, characterized in that: Before testing the signal intensity corresponding to each impurity element to be measured at each preset concentration by the inductively coupled plasma mass spectrometer, the instrument is tuned first. The hafnium-based tuning solution is prepared using the Tune A standard solution, and the prepared hafnium-based tuning solution is placed in the injection tube of the inductively coupled plasma mass spectrometer to observe the intensity values ​​of Li, Co, In, and U to ensure that they meet the requirements.

10. The method for determining impurity elements in hafnium oxide according to claim 9, characterized in that: It also includes S6, sample test effect verification; S6.1: Verify the test results of the impurity elements to be tested in the pure hafnium metal storage solution; S6.2: Verify the test results of the impurity elements to be tested in the hafnium oxide sample.

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