Method for rapidly eliminating hafnium memory effect in ICP-MS determination
By using a combination of HF, HF and HNO3 mixed solutions, and HF and H2O2 mixed solutions for cleaning in the ICP-MS injection system, the problem of the difficulty in removing the Hf memory effect was solved, achieving rapid and effective Hf removal and improving detection accuracy and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-07-20
- Publication Date
- 2026-04-10
AI Technical Summary
The memory effect of Hf in ICP-MS is difficult to remove effectively. Conventional cleaning methods are time-consuming and ineffective, resulting in wasted resources and decreased detection accuracy.
The ICP-MS injection system was sequentially cleaned with HF, a mixed solution of HF and HNO3, and a mixed solution of HF and H2O2. Hf was gradually removed according to the different adsorption capacities and concentrations of the residues. Finally, the instrument was protected with ultrapure water.
The method quickly and effectively removes the Hf memory effect, improving the detection accuracy and efficiency of ICP-MS and reducing interference with other elements.
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Figure CN115656309B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of ICP-MS determination, and particularly relates to a method for rapidly reducing hafnium memory effect in ICP-MS determination. BACKGROUND
[0002] With the development of semiconductor technology, the integration of chips is continuously improved, and the size of devices is continuously reduced, and the requirements for electronic materials are higher and higher, especially in the fields of film plating and photoresist. Atomic layer deposition (ALD) is a thin film forming technology using continuous chemical reactions in the gas phase, which can accurately control the film thickness at the atomic layer level, and the prepared thin film has high purity, good uniformity and good retention, and therefore is highly concerned. Since the purity of the ALD source has a great influence on the film plating, therefore, the impurity control of the ALD source is particularly important. There are various types of ALD sources, and the biggest difficulty in the purity detection process is that the substrate of the ALD source is a metal organic matter itself, and high-concentration matrix metals will be introduced during ICP-MS detection, and these matrix metals will be left in the atomization chamber, connecting pipe, square pipe, interception cone, sampling cone, lens and other places of ICP-MS to form memory effect, which will form interference when analyzing the next sample, and affect the quantitative analysis of some elements, such as hafnium memory effect: Hf ++ (180)---Zr + (90), Hf + , HfH + (180, 181)---Ta + (180, 181).
[0003] The hafnium (Hf) memory effect in ICP-MS has always been a difficult problem in analysis, and the conventional cleaning method has no good effect on the hafnium memory effect. At present, the cleaning of Hf adsorbed in the ICP-MS sampling system is mainly through the following steps: (1) first, the atomization chamber of the ICP-MS is disassembled and washed with ultrapure water, then the torch pipe is disassembled and soaked in 5% HNO3 solution for 24 hours, then washed with ultrapure water and dried, and finally the interception cone and sampling cone are disassembled and wiped with aluminum oxide powder solution, washed with ultrapure water and dried; (2) after the disassembled atomization chamber, torch pipe, interception cone and sampling cone are installed, the instrument is started, and 3%-5% HNO3 solution is used to clean the Hf adsorbed in the ICP-MS sampling system, but there is no obvious change in the Hf remaining in the ICP-MS sampling system after 2 hours of cleaning. It can be seen that the current treatment technology basically has no effect on the removal of hafnium memory effect, and a special ICP-MS for determining Hf source is usually required, which causes waste of resources. Therefore, a method for rapidly reducing hafnium memory effect in ICP-MS determination is urgently needed to improve the accuracy and detection efficiency of ICP-MS. SUMMARY
[0004] The technical problem solved by the present application is to provide a method for quickly reducing Hf memory effect in ICP-MS determination.
[0005] To solve the above technical problem, the present application provides the following technical scheme:
[0006] The present application provides a method for quickly reducing Hf memory effect in ICP-MS determination, comprising the following steps:
[0007] (1) using HF solution, HF and HNO3 mixed solution, HF and H2O2 mixed solution to clean the ICP-MS sampling system in turn; the concentration of the HF solution is 2%-5%, the concentration of each component in the HF and HNO3 mixed solution is 2%-5%, the concentration of HF in the HF and H2O2 mixed solution is 2%-5%, and the concentration of H2O2 is 20%-40%;
[0008] (2) monitoring the Hf element signal value during the cleaning process, and repeating the cleaning step until the Hf element signal value is reduced to the required value.
[0009] According to the present application, different solutions are used to clean the ICP-MS sampling system according to the adsorption capacity of the residues in the system and the different concentrations of the residues. First, a HF solution with a concentration of 2%-5% is used to dissolve the Hf adsorbed in the sampling system and to destroy the Hf oxide film protective layer. Then, a HF and HNO3 mixed solution is used to further dissolve the Hf ions adsorbed in the sampling system, and to dissolve and separate the residual small amount of Hf chloride (usually a certain amount of hafnium tetrachloride is left in the ALD hafnium precursor source) in the sampling system. Further, a HF and H2O2 mixed solution is used to dissolve and separate the uneluted Hf nitride in the sampling system, thereby achieving the effect of deep cleaning of Hf in the sampling system. The process needs to prepare cleaning solutions with appropriate concentrations to achieve the elution effect while avoiding damage to the system.
[0010] Further, during the Hf-containing sample testing stage, a mixed solution of nitric acid and hydrofluoric acid is used as the medium for the Hf-containing sample; both the nitric acid and the hydrofluoric acid are electronic-grade solvents with an impurity content of ≤100 ppt.
[0011] Further, the Hf-containing sample is a hafnium precursor source used in atomic deposition technology, and the hafnium precursor source is tetrakis(dimethylamino)hafnium, tetrakis(ethylmethylamino)hafnium, tetrakis(diethylamino)hafnium or tris(dimethylamino)cyclopentadienylhafnium.
[0012] Further, in step (1), the HF solution, the HF and HNO3 mixed solution and the HF and H2O2 mixed solution are sequentially cleaned for 10-15 minutes.
[0013] Further, in step (1), the HF solution is prepared by using ultrapure hydrofluoric acid and ultrapure water, the HF and HNO3 mixed solution is prepared by using ultrapure hydrofluoric acid, ultrapure nitric acid and ultrapure water, and the HF and H2O2 mixed solution is prepared by using ultrapure hydrofluoric acid, ultrapure hydrogen peroxide and ultrapure water.
[0014] Further, the impurity content in the ultrapure hydrofluoric acid, ultrapure nitric acid and ultrapure hydrogen peroxide is ≤100 ppt.
[0015] Further, in step (1), the concentration of the HF solution is 3%, the concentration of each component in the HF and HNO3 mixed solution is 3%, and the concentration of HF in the HF and H2O2 mixed solution is 3% and the concentration of H2O2 is 30%.
[0016] Further, before cleaning the ICP-MS sample system, the atomizing chamber of the ICP-MS is first disassembled, the atomizing chamber is flushed with ultrapure water, and then the atomizing chamber is installed on the ICP-MS after flushing. The residual solution in the atomizing chamber is cleaned.
[0017] Further, in step (2), the Hf element signal value is measured in the helium tuning mode.
[0018] Further, the method further comprises a process of finally cleaning with ultrapure water; after the sample system is washed with the above-mentioned acidic and strong oxidizing solution, in order to avoid damage to the instrument caused by residual cleaning solution, and further to remove a small amount of cleaning solution in which Hf ions are dissolved and remain in the sample system, finally, the system is washed with ultrapure water for not less than 10 minutes, which reduces the residual Hf ions and also protects the instrument to a certain extent.
[0019] Further, the present application uses HF solution, HF and HNO3 mixed solution and HF and H2O2 mixed solution to clean the sample system, but is not limited to the order of sequentially using HF solution, HF and HNO3 mixed solution and HF and H2O2 mixed solution for washing. It has been verified by experiments that the effect of sequentially using HF solution, HF and HNO3 mixed solution and HF and H2O2 mixed solution for washing is the best.
[0020] Further, the required value is 0-50 cps; when the instrument background value is less than 50 cps, the detection of other samples will not be disturbed.
[0021] The beneficial effects of the present application are:
[0022] The present application adopts different cleaning solutions to clean the sample injection system according to the adsorption ability of different Hf-containing residues, without disassembling the instrument lens, quadrupole and other instrument components, so that the cleaning process is simple and easy to monitor, Hf in the sample injection system can be quickly removed in a short time, the memory effect of Hf in ICP-MS determination is effectively reduced, the accuracy of ICP-MS detection of Hf and elements such as Yb, Lu, Ta, W, Rb, Sr, Y, Zr, Ba and other elements interfered by Hf is improved, and the detection efficiency of ICP-MS is improved. BRIEF DESCRIPTION OF DRAWINGS
[0023] Figure 1 Hf residue in the instrument after batch processing in Example 1;
[0024] Figure 2 Hf residue in the instrument after cleaning with solution A for 10 minutes in Example 1;
[0025] Figure 3 Hf residue in the instrument after cleaning with mixed solution B for 10 minutes in Example 1;
[0026] Figure 4 Hf residue in the instrument after cleaning with mixed solution C for 10 minutes in Example 1;
[0027] Figure 5 Hf residue in the instrument after cleaning with ultrapure water for 10 minutes in Example 1;
[0028] Figure 6 Hf residue in the instrument after batch processing in Example 2;
[0029] Figure 7 Hf residue in the instrument after cleaning with 3% HF for 1 hour in Example 2;
[0030] Figure 8 Hf residue in the instrument after cleaning with solution A, mixed solution B, mixed solution C and ultrapure water in Example 2;
[0031] Figure 9 Hf residue in the instrument after batch processing in Comparative Example 1;
[0032] Figure 10 Hf residue in the instrument after cleaning with 3% HNO3 solution for 1 hour in Comparative Example 1. DETAILED DESCRIPTION
[0033] The present application will be further described below in conjunction with the drawings and specific embodiments so that those skilled in the art can better understand and implement the present application, but the embodiments are not intended to limit the present application.
[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used in this description, the singular forms "a", "an" and "the" include plural references unless the context clearly dictates otherwise.
[0035] Example 1
[0036] This example relates to the testing of tetrakis(dimethylamino)hafnium by ICP-MS and the removal of the memory effect of Hf in ICP-MS determination after testing, and the specific operation is as follows:
[0037] (1) In an inert atmosphere, 0.1 g of tetrakis(dimethylamino)hafnium was weighed into a PTFE digestion tank, 8 mL of electronic grade nitric acid and 0.5 mL of electronic grade hydrofluoric acid were added, and four sets of parallel samples were taken, and 8 mL of electronic grade nitric acid and 0.5 mL of electronic grade hydrofluoric acid were added to the empty digestion tank as a control blank.
[0038] (2) The digestion tank was placed in a microwave digestion instrument, and the temperature program was set as follows: 120°C for 5 min, 140°C for 5 min, 160°C for 5 min, 180°C for 5 min, 200°C for 5 min, and 220°C for 5 min.
[0039] (3) After digestion was completed, the sample was cooled and transferred to a peeled PFA sample bottle, and water was added to make up to 100 g. The control blank was also treated in the same way.
[0040] (4) Turn on the ICP-MS, stabilize for 30 minutes, then tune the instrument, and use the standard addition method to establish batch processing, which is shown as follows:
[0041]
[0042]
[0043] (5) After the instrument completes batch processing, open the element signal monitoring to check the residual Hf, and the memory effect of Hf is more residual in ICP-MS.
[0044] The residual Hf in the ICP-MS sample introduction system was cleaned by using the conventional cleaning method and the method described in the present application, respectively, as follows:
[0045] Prepare the cleaning solution:
[0046] Preparation of solution A: 3% HF solution was prepared by using purchased electronic grade HF (TAMAPure AA-100 ultra-pure hydrofluoric acid, impurity ≤100 ppt, concentration 38%) and ultra-pure water;
[0047] Preparation of mixed solution B: 3% HF and 3% HNO3 mixed solution was prepared by using purchased electronic grade HF and electronic grade HNO3 (TAMAPure AA-100 ultra-pure nitric acid, impurity ≤100 ppt, concentration 55%) and ultra-pure water;
[0048] Preparation of mixed solution C: 30% H2O2 and 3% HF mixed solution was prepared by using purchased electronic grade HF and electronic grade H2O2 (TAMAPure AA-100 hydrogen peroxide, impurity ≤100 ppt, concentration 55%) and ultra-pure water.
[0049] Cleaning: Before cleaning, the signal of Hf was 4702 cps as shown in FIG. 1. The prepared solution A, mixed solution B, mixed solution C and ultra-pure water were used for cleaning in turn for 10 minutes. After cleaning with the prepared solution A for 10 minutes, the signal of Hf was observed to be 2204 cps as shown in FIG. 2. After cleaning with the prepared mixed solution B for 10 minutes, the signal of Hf was observed to be 1478.8 cps as shown in FIG. 3. After cleaning with the prepared mixed solution C for 10 minutes, the signal of Hf was observed to be 741 cps as shown in FIG. 4. Finally, after cleaning with ultra-pure water for 10 minutes, the signal of Hf in the instrument was reduced to 20.6 cps as shown in FIG. 5, and the residual content did not interfere with the analysis of other types of samples, that is, the memory effect of Hf in the instrument was effectively removed. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5
[0050] Example 2
[0051] This example relates to the testing of tetra(ethylmethylamino)hafnium by ICP-MS, and the use of different cleaning methods to remove Hf remaining in the ICP-MS instrument after testing, which is specifically as follows:
[0052] (1) In an inert atmosphere, 0.05 g of tetraethylmethylamino hafnium was weighed into a PTFE digestion tank, 5 mL of electronic grade nitric acid and 0.3 mL of electronic grade hydrofluoric acid were added, and four sets of parallel samples were taken. In the empty digestion tank, 5 mL of electronic grade nitric acid and 0.3 mL of electronic grade hydrofluoric acid were added as a control blank.
[0053] (2) The weighed digestion tank was placed open on a graphite acid-removing instrument and placed in a fume hood. The temperature of the graphite acid-removing instrument was set to 240°C, and the heating time was 300 min.
[0054] (3) After the acid is removed, the sample is cooled and then transferred to a peeled PFA sample bottle, and 0.5% electronic grade nitric acid is added to make up to 100g.
[0055] (4) After the ICP-MS is opened, the instrument is tuned after being stabilized for 30 minutes, and the batch processing is established using an external standard method, as shown in the following table:
[0056] Blank 0 ppb Standard 1 1 ppb Standard 2 2 ppb Standard 3 3 ppb Control blank Sample 1 Sample 2 Sample 3 Sample 4
[0057] (5) After the instrument completes the batch processing, the signal of the element is monitored to check the residual Hf, and the memory effect of Hf is more residual in the ICP-MS.
[0058] The residual Hf in the ICP-MS sample introduction system is cleaned by using a single 3% HF solution and the method described in the application, respectively, as follows:
[0059] Prepare the cleaning solution:
[0060] Prepare solution A: A purchased electronic grade HF (TAMA Pure AA-100 ultra-pure hydrofluoric acid, impurity ≤100 ppt, concentration 38%) is added to ultra-pure water to prepare a 3% HF solution;
[0061] Prepare mixed solution B: A purchased electronic grade HF and electronic grade HNO3 are added to ultra-pure water to prepare a mixed solution of 3% HF and 3% HNO3;
[0062] Prepare mixed solution C: A purchased electronic grade HF and electronic grade H2O2 (TAMA Pure AA-100 hydrogen peroxide, impurity ≤100 ppt, concentration 55%) are added to ultra-pure water to prepare a mixed solution of 30% H2O2 and 3% HF.
[0063] Cleaning:
[0064] Single 3% HF solution cleaning: The Hf signal before cleaning is 6037 cps, as shown in Figure 6 The result of cleaning with a 3% HF solution for 1h is shown in Figure 7 The Hf signal value decreased from the original 6037 cps to 2668.5 cps.
[0065] After cleaning with the above-mentioned single 3% HF solution for 1h, the method described in the application is used for subsequent cleaning, i.e., solutions A, mixed solution B, mixed solution C and ultra-pure water are each cleaned for 10 minutes, as shown in Figure 8 The Hf signal is observed to be reduced to 34.8 cps, and the instrument background value is less than 50 cps, which meets the detection requirements and will not interfere with the detection of other samples.
[0066] Comparative Example 1
[0067] The present comparative example relates to the testing of tetra(dimethylamino)hafnium by ICP-MS and the removal of the memory effect of Hf in the ICP-MS determination after testing, and the specific operation is as follows:
[0068] (1) In an inert atmosphere, 0.1 g of tetra(dimethylamino)hafnium was weighed into a PTFE digestion tank, 8 mL of electronic grade nitric acid and 0.5 mL of electronic grade hydrofluoric acid were added, and four sets of parallel samples were taken, and 8 mL of electronic grade nitric acid and 0.5 mL of electronic grade hydrofluoric acid were added to the empty digestion tank as a control blank.
[0069] (2) The digestion tank was placed in a microwave digestion instrument, and the temperature program was set as follows: 120°C for 5 min, 140°C for 5 min, 160°C for 5 min, 180°C for 5 min, 200°C for 5 min, and 220°C for 5 min.
[0070] (3) After digestion was completed, the sample was cooled and transferred to a peeled PFA sample bottle, and water was added to make up to 100 g. The control blank was also treated in the same way.
[0071] (4) Turn on the ICP-MS, stabilize for 30 minutes, then tune the instrument, and use the standard addition method to establish batch processing, which is shown as follows:
[0072] Standard 1 0 ppb Standard 2 1 ppb Standard 3 2 ppb Standard 4 3 ppb Control blank Sample 1 Sample 2 Sample 3 Sample 4
[0073] (5) After the instrument completes batch processing, open the element signal monitoring to check the residual Hf, and the memory effect of Hf is more in the ICP-MS.
[0074] The present comparative example uses a conventional cleaning method to clean the residual Hf in the ICP-MS sample introduction system, which is as follows:
[0075] Prepare the cleaning solution: use purchased electronic grade HNO3 (TAMA Pure AA-100 ultra-pure nitric acid, impurities ≤100 ppt, concentration 55%) and ultrapure water to prepare a 3% HNO3 solution;
[0076] Cleaning: Before cleaning, the Hf signal is 5731.9 cps as shown in Figure 9 . Using a 3% HNO3 solution for cleaning for 1 h, the result is shown in Figure 10 , and the Hf signal value decreases from the original 5731.9 cps to 5082.3 cps.
[0077] The ICP-MS sample injection system residual Hf after detecting the same substance in Comparative Example 1 and Example 1 was cleaned. Comparative Example 1 used a conventional cleaning method, and Example 1 used the method described in the application, i.e. using prepared solution A, mixed solution B, mixed solution C and ultrapure water to clean for 10 minutes each. The cleaning effect of Comparative Example 1 and Example 1 can be compared. Comparative Example 1 used a single 3% HNO3 solution to clean the system for a long time, and the concentration of Hf in the sample injection system hardly changed, the cleaning efficiency was low and the effect was poor. However, using the cleaning method described in Example 1, the Hf in the system can be reduced to below 50 cps within a certain period of time, meeting the needs of other sample detection.
[0078] As can be seen from the above examples and comparative examples, the method for reducing Hf memory effect in ICP-MS determination described in the application can quickly and efficiently remove residual Hf of different Hf-containing compounds in the instrument. Compared with the conventional cleaning method, the efficiency of daily detection is greatly improved, and after one round of washing, the residual Hf in the instrument is less than 50 cps, which will not interfere with the analysis of other types of samples, greatly improving the accuracy of ICP-MS.
[0079] The above examples are only preferred embodiments for fully illustrating the application, and the protection scope of the application is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the application are within the protection scope of the application. The protection scope of the application is subject to the claims.
Claims
1. A method for rapidly reducing the memory effect of Hf in ICP-MS determination, characterized in that, The method comprises the following steps: (1) sequentially cleaning the ICP-MS sample introduction system with HF solution, HF and HNO3 mixed solution, and HF and H2O2 mixed solution, and finally cleaning with ultrapure water, wherein the HF solution, the HF and HNO3 mixed solution, and the HF and H2O2 mixed solution are sequentially cleaned for 10-15 minutes, and the ultrapure water cleaning process is not less than 10 minutes; the mass concentration of the HF solution is 2%-5%, the mass concentration of each component in the HF and HNO3 mixed solution is 2%-5%, the mass concentration of HF in the HF and H2O2 mixed solution is 2%-5%, and the mass concentration of H2O2 is 20%-40%; (2) monitoring the Hf element signal value during the cleaning process, and repeating the cleaning step until the Hf element signal is reduced to a required value; the required value is 0-50 cps; During the Hf-containing sample testing stage, a mixed solution of nitric acid and hydrofluoric acid is used as the medium of the Hf-containing sample, and the Hf-containing sample is a hafnium precursor source used in atomic deposition technology.
2. The method of claim 1, wherein, The hafnium precursor source is tetrakis(dimethylamino)hafnium, tetrakis(ethylmethylamino)hafnium, tetrakis(diethylamino)hafnium, or tris(dimethylamino)cyclopentadienylhafnium.
3. The method of claim 1, wherein, In step (1), the HF solution is prepared by using ultrapure hydrofluoric acid and ultrapure water, the HF and HNO3 mixed solution is prepared by using ultrapure hydrofluoric acid, ultrapure nitric acid, and ultrapure water, and the HF and H2O2 mixed solution is prepared by using ultrapure hydrofluoric acid, ultrapure hydrogen peroxide, and ultrapure water.
4. The method of claim 3, wherein, The impurity content in the ultrapure hydrofluoric acid, the ultrapure nitric acid, and the ultrapure hydrogen peroxide is ≤100 ppt.
5. The method of claim 1, wherein, In step (1), the mass concentration of the HF solution is 3%, the mass concentration of each component in the HF and HNO3 mixed solution is 3%, the mass concentration of HF in the HF and H2O2 mixed solution is 3%, and the mass concentration of H2O2 is 30%.
6. The method of claim 1, wherein, Before cleaning the ICP-MS sample introduction system, the atomization chamber of the ICP-MS is first disassembled, and then the atomization chamber is flushed with ultrapure water, and then installed on the ICP-MS.
7. The method of claim 1, wherein, In step (2), the Hf element signal value is monitored in the helium tuning mode.