A method for measuring the purity of metal-based precursors using the internal standard method

Abstract

This invention provides a method for detecting the purity of metal-based precursors. The method employs an internal standard method to measure the purity of the metal-based precursor. The deuterated reagent used is deuterated benzene, and the internal standard is anhydrous toluene solvent, with purity at analytical or chromatographic grade. Approximately 0.5 ml of the deuterated reagent is added to an NMR tube. After the sample and internal standard are fully dissolved, the solution is transferred to the NMR tube for NMR analysis. The test results are quantified using an internal standard calibration curve. A series of internal standard solutions with known concentrations are prepared, with the internal standard weight set at 20 mg and sample weights at 5 mg, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, and 35 mg. These solutions are simultaneously analyzed with the sample using NMR, and the peak areas or peak heights of the internal standard and target substance are recorded. Finally, an internal standard calibration curve is established based on the response ratio between the internal standard and the target substance. Subsequently, for samples of any concentration, 20 mg of the internal standard is added, and samples of any weight from 5 mg to 35 mg are selected. The specific concentration of the sample can then be obtained using the internal standard calibration curve.

Description

Technical Field

[0001] This invention belongs to the technical field of purity detection methods for metal precursors, specifically relating to a purity detection method for cyclopentadienyltris(dimethylamino)zirconium. Background Technology

[0002] Metal-based precursors are compounds used to prepare metals or alloys; these compounds can be transformed into the desired metallic materials under specific synthetic conditions. Metal precursors play a crucial role in semiconductor manufacturing, primarily used in thin-film deposition processes to form metal thin-film layers that meet the requirements of integrated circuit manufacturing. These thin-film layers serve as key components such as capacitor electrodes, gate transition layers, and isolation materials in semiconductor devices such as logic chips and memory chips. With the development of advanced processes, the technical requirements for metal precursors are constantly increasing, driving their research and application progress. However, current methods for detecting the purity of some metal precursors are limited to ICP-MS, LC-MS, titration, and NMR. ICP-MS can only measure metal purity, and it has no effect on the purity of some metal precursors containing byproducts with the same properties as the product. LC-MS can measure the purity of some relatively stable and highly polar metal precursors, but it cannot detect the purity of metal precursors that readily react with water and have very low polarity. Titration requires the selection of a titrant that quantitatively reacts with the main component of the metal precursor, and the reaction endpoint is determined by the color change or potential jump of the indicator. However, this method has the drawback of not being able to determine the purity of the reacting metal precursor when the byproducts have the same properties as the product. Nuclear magnetic resonance (NMR) is a powerful tool for the qualitative analysis of organic compounds. Since the area or height of the resonance peak in NMR is proportional to the number of protons in that peak, this method can also be used for quantitative analysis.

[0003] Nuclear Magnetic Resonance (NMR) is well-known as a representative analytical method for the structural analysis of organic compounds. However, because it directly observes the atoms (nuclear spins) that make up molecules, it is quantitative in principle and is also used for quantitative analysis. Quantitative NMR, recently known as qNMR, is primarily used for compositional analysis of polymers, quantification of terminal groups, and concentration and purity analysis of low-molecular-weight molecules. Specifically, analysis is performed by comparing the integrated values ​​of the signals from an internal standard and the sample in the NMR spectrum. When two signals come from different compounds (a, b), the signal intensities (integrals) and the concentrations of the compounds are represented by Equation 1. Therefore, sample preparation can be rigorously achieved using an internal standard of known purity in a compound.

[0004]

[0005] Ix = integral value of sample peak; Is = integral value of internal standard peak; Wx = sample weight (mg); Ws = internal standard weight (mg); Mx = molecular weight of sample; Ms = molecular weight of internal standard; Nx = number of protons in the selected sample peak; Ns = number of protons in the selected internal standard; Ps = purity of internal standard, %; Px = purity of sample, %.

[0006] The current method for measuring the purity of metal-based precursors using the internal standard method suffers from limitations in reproducibility due to weighing issues and an approximately 5% error in NMR purity measurements. Therefore, an improvement was made. A series of internal standard solutions with known concentrations were prepared, with the internal standard weight set at 20 mg and sample weights at 5 mg, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, and 35 mg. These solutions and samples were then simultaneously analyzed using NMR, and the peak areas or heights of the internal standard and target substance were recorded. Finally, an internal standard calibration curve was established based on the response ratio between the internal standard and target substance. Subsequently, by adding 20 mg of the internal standard to any sample concentration and selecting samples of any weight from 5 mg to 35 mg, the specific concentration of the sample can be obtained through the internal standard calibration curve. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for measuring the purity of metal-based precursors using the internal standard method.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a method for measuring the purity of metal-based precursors, wherein the detection method uses the internal standard method to measure the purity of cyclopentadienyltris(dimethylamino)zirconium, and the specific detection method is as follows: Step 1: Weigh the sample and anhydrous internal standard into the same EP tube, add deuterated reagent to dissolve, and after the sample and internal standard are fully dissolved, transfer to an NMR tube for instrument testing; Step Two: On-computer experiment and parameter settings; Step 3: Establish the internal standard calibration curve: Perform NMR analysis on the internal standard and the sample simultaneously, and record the peak area or peak height of the internal standard and the target substance. Establish an internal standard calibration curve based on the response ratio between the internal standard and the target substance. When measuring any concentration of sample, only 20 mg of internal standard needs to be added. Select any weight of sample from 5 mg to 35 mg, and the specific concentration of the sample can be obtained through the internal standard calibration curve.

[0009] Peak labeling and integration of the quantitative 1H NMR data, along with baseline and peak phase correction, can reduce integration errors introduced by spectral processing. These solutions and samples are then subjected to simultaneous NMR analysis, with peak areas or heights of the internal standard and target substance recorded. Finally, an internal standard calibration curve is established based on the response ratio between the internal standard and target substance. Subsequently, by selecting samples of any concentration, adding 20 mg of internal standard, and choosing samples of any weight from 5 mg to 35 mg, the specific concentration of the sample can be obtained through the internal standard calibration curve.

[0010] In step one, the deuterated reagent is a deuterated benzene, deuterated DMSO, deuterated tetrahydrofuran, deuterated acetone, etc., preferably a deuterated benzene.

[0011] In step one, the internal standard is toluene, 1,3,5-trimethoxybenzene, o-xylene, etc., preferably toluene reagent, with analytical grade or chromatographic grade, and the sample is anhydrous.

[0012] In step one, the purity of the internal standard is above 99%, meaning it is of analytical or chromatographic purity.

[0013] In step two, the method for treating the anhydrous internal standard is as follows: the 5A molecular sieve is dried in a drying oven for 20-24 hours, and then the reagent is soaked in a glove box for 20-24 hours to make the water content less than 1 ppm.

[0014] In step two, the sample is cyclopentadienyl tris(dimethylamino)zirconium, cyclopentadienyl tris(dimethylamino)hafnium, tetra(dimethylamino)zirconium, or tetra(dimethylamino)hafnium.

[0015] In step three, the NMR parameters are set as described above. The number of scans (NS) should be sufficient, at least 64, to ensure a high signal-to-noise ratio. The excitation center (O1P) should be positioned between the selected sample peak and the internal standard peak to eliminate the influence of pulsed excitation off-resonance. The relaxation delay time (D1) should be sufficiently large to ensure complete signal relaxation during repeated scans. Generally, it is set to >5-7 times T1. In practice, T1 is not measured, so D1 can be set as long as possible in the experiment, generally above 15 seconds.

[0016] In step four, the formula for the internal standard calibration curve is: ; The sample mass is 5-35 mg, and the anhydrous internal standard is 10-20 mg.

[0017] In some preferred embodiments, this method involves preparing a series of internal standard solutions of known concentrations, with the internal standard weighing 20 mg and sample weights of 5 mg, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, and 35 mg. These solutions are then simultaneously analyzed with the samples using NMR, and the peak areas or peak heights of the internal standard and target substance are recorded. Finally, an internal standard calibration curve is established based on the response ratio between the internal standard and the target substance. Subsequently, any concentration of sample is selected, 20 mg of the internal standard is added, and any sample weight from 5 mg to 35 mg is chosen; the specific concentration of the sample can then be obtained through the internal standard calibration curve.

[0018] The beneficial effects of this invention are: a suitable detection method for the purity of metal-based precursors has been selected and optimized; an internal standard calibration curve is established based on the response ratio between the internal standard and the target substance by adding an internal standard; and a method for measuring the purity of metal-based precursors using the internal standard method is provided, which solves the problem that the traditional internal standard method for measuring the purity of metal-based precursors cannot achieve repeatability verification experiments due to weighing issues. Attached Figure Description

[0019] Figure 1 The NMR curve is obtained in Example 2.

[0020] Figure 2 This is the standard curve obtained by fitting in Example 2.

[0021] Figure 3 This is the standard curve obtained by fitting in Example 3.

[0022] Figure 4 This is the standard curve obtained by fitting in Example 4. Detailed Implementation

[0023] Example 1 Internal standard method for NMR determination of metal-based precursors Using a 0.02 g / mL balance, precisely weigh approximately 0.02 g of cyclopentadienyltris(dimethylamino)zirconium and approximately 0.02 g of anhydrous tetrahydrofuran reagent, respectively. Dissolve them in approximately 0.5 mL of deuterated reagent. After the sample and internal standard are fully dissolved, transfer them to an NMR tube for NMR analysis. Substituting the various signal intensities (integrals) and the added weights into the following formulas, the results shown in Table 1 can be obtained.

[0024] , Table 1 Results of NMR determination of metal-based precursors using the internal standard method

[0025] Example 2 Step 1: Select a suitable deuterated reagent and a suitable internal standard, namely deuterated benzene and anhydrous toluene solvent.

[0026] Step 2: Pre-processing Using a 1 / 100,000 balance, accurately weigh the sample cyclopentadienyl tris(dimethylamino)zirconium and the internal standard anhydrous toluene into the same EP tube, and record the weighing values. The anhydrous toluene weighed should be about 20 mg, and the sample weights should be about 5 mg, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, and 35 mg, respectively. Add about 0.5 ml of deuterated reagent to dissolve them. After the sample and internal standard are fully dissolved, transfer them to NMR tubes for NMR testing.

[0027] Step 3: On-computer experiment and parameter settings The NMR parameters should be set such that the number of scans (NS) is sufficient, at least 64, to ensure a high signal-to-noise ratio. The excitation center (O1P) should be positioned between the selected sample peak and the internal standard peak to eliminate the influence of pulsed excitation off-resonance. The relaxation delay time (D1) should be sufficiently large to ensure complete signal relaxation during repeated scans, generally set to >5-7 times T1. Since T1 is not typically measured in practice, D1 can be set as long as possible in experiments, generally above 15 seconds.

[0028] Step 4: Establish internal standard calibration curve Open the NMR data using MestReNova, process the data, and list the data, such as... Figure 2 As shown.

[0029] Peak labeling and integration of the quantitative proton NMR data, along with baseline and peak phase correction, can reduce integration errors caused by spectral processing. Subsequently, these solutions and samples are simultaneously subjected to NMR analysis, and the peak areas or peak heights of the internal standard and target substances are recorded, as shown in the table below.

[0030]

[0031] Finally, an internal standard calibration curve is established based on the response ratio between the internal standard and the target substance. The formula for the internal standard calibration curve is:

[0032] S 产 : The integral of the 1H NMR spectrum of the CpZr addition amount; S 内 : The integral of the 1H NMR spectrum of the amount of internal standard added; m 产 : The weight added by CpZr; m 内 : Weight added to the internal standard; C 产 : Concentration of CpZr products; C 内 : Concentration of internal standard.

[0033] Fitting the above data to this formula yields the following result. Figure 2 The curve shown.

[0034] The final fitted curve is determined as follows:

[0035] Then, any concentration of sample can be selected, and about 20 mg of anhydrous toluene can be added. Select any weight of sample from 5 mg to 35 mg, and the specific concentration of the sample can be obtained through the internal standard calibration curve.

[0036] Example 3 Step 1: Select appropriate deuterated reagents and appropriate internal standards, namely deuterated benzene and anhydrous 1,3,5-trimethoxybenzene solvent.

[0037] Step 2: Pre-processing Using a 1 / 100,000 balance, accurately weigh the sample cyclopentadienyl tris(dimethylamino)zirconium and the internal standard anhydrous toluene into the same EP tube, and record the weight values. The anhydrous 1,3,5-trimethoxybenzene was selected to be about 20 mg. The sample weights were about 5 mg, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, and 35 mg, respectively. Add about 0.5 ml of deuterated reagent to dissolve them. After the sample and internal standard were fully dissolved, they were transferred to NMR tubes for NMR testing.

[0038] Step 3: On-computer experiment and parameter settings The NMR parameters should be set such that the number of scans (NS) is sufficient, at least 64, to ensure a high signal-to-noise ratio. The excitation center (O1P) should be positioned between the selected sample peak and the internal standard peak to eliminate the influence of pulsed excitation off-resonance. The relaxation delay time (D1) should be sufficiently large to ensure complete signal relaxation during repeated scans, generally set to >5-7 times T1. Since T1 is not typically measured in practice, D1 can be set as long as possible in experiments, generally above 15 seconds.

[0039] Step 4: Establish internal standard calibration curve Open the NMR data using MestReNova, process the data, and list the data, such as... Figure 2 As shown.

[0040] Peak labeling and integration of the quantitative proton NMR data, along with baseline and peak phase correction, can reduce integration errors caused by spectral processing. Subsequently, these solutions and samples are simultaneously subjected to NMR analysis, and the peak areas or peak heights of the internal standard and target substances are recorded, as shown in the table below.

[0041]

[0042] Finally, an internal standard calibration curve is established based on the response ratio between the internal standard and the target substance. The formula for the internal standard calibration curve is:

[0043] S 产 : The integral of the 1H NMR spectrum of the CpZr addition amount; S 内 : The integral of the 1H NMR spectrum of the amount of internal standard added; m 产 : The weight added by CpZr; m 内 : Weight added to the internal standard; C 产 : Concentration of CpZr products; C 内 : Concentration of internal standard.

[0044] Fitting the above data to this formula yields the following result. Figure 3 The curve shown.

[0045] The final fitted curve is determined as follows:

[0046] Then, any concentration of sample can be selected, and about 20 mg of anhydrous 1,3,5-trimethoxybenzene can be added. Select any weight of sample from 5 mg to 35 mg, and the specific concentration of the sample can be obtained through the internal standard calibration curve.

[0047] Example 4 Step 1: Select a suitable deuterated reagent and a suitable internal standard, namely deuterated benzene and anhydrous o-xylene solvent.

[0048] Step 2: Pre-processing Using a 1 / 100,000 balance, accurately weigh the sample cyclopentadienyl tris(dimethylamino)zirconium and the internal standard anhydrous toluene into the same EP tube, and record the weighing values. The anhydrous o-xylene weighed is approximately 20 mg, and the sample weights are approximately 5 mg, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, and 35 mg, respectively. Add approximately 0.5 ml of deuterated reagent to dissolve them. After the sample and internal standard are fully dissolved, transfer them to NMR tubes for NMR testing.

[0049] Step 3: On-computer experiment and parameter settings The NMR parameters should be set such that the number of scans (NS) is sufficient, at least 64, to ensure a high signal-to-noise ratio. The excitation center (O1P) should be positioned between the selected sample peak and the internal standard peak to eliminate the influence of pulsed excitation off-resonance. The relaxation delay time (D1) should be sufficiently large to ensure complete signal relaxation during repeated scans, generally set to >5-7 times T1. Since T1 is not typically measured in practice, D1 can be set as long as possible in experiments, generally above 15 seconds.

[0050] Step 4: Establish internal standard calibration curve Open the NMR data using MestReNova, process the data, and list the data, such as... Figure 2 As shown.

[0051] Peak labeling and integration of the quantitative proton NMR data, along with baseline and peak phase correction, can reduce integration errors caused by spectral processing. Subsequently, these solutions and samples are simultaneously subjected to NMR analysis, and the peak areas or peak heights of the internal standard and target substances are recorded, as shown in the table below.

[0052]

[0053] Finally, an internal standard calibration curve is established based on the response ratio between the internal standard and the target substance. The formula for the internal standard calibration curve is:

[0054] S 产 : The integral of the 1H NMR spectrum of the CpZr addition amount; S 内 : The integral of the 1H NMR spectrum of the amount of internal standard added; m 产 : The weight added by CpZr; m 内 : Weight added to the internal standard; C 产 : Concentration of CpZr products; C 内 : Concentration of internal standard.

[0055] Fitting the above data to this formula yields the following result. Figure 4 The curve shown.

[0056] The final fitted curve is determined as follows:

[0057] Then, any concentration of sample can be selected, and about 20 mg of anhydrous o-xylene can be added. Select any weight of sample from 5 mg to 35 mg, and the specific concentration of the sample can be obtained through the internal standard calibration curve.

[0058] Traditional internal standard methods for measuring the purity of metal-based precursors using NMR suffer from limitations due to weighing issues and an NMR quantitative error of approximately 5%, making repeatability verification experiments difficult and resulting in significant variations in sample repeatability. Therefore, this invention improves upon this method, with the specific steps as follows: 1. Prepare a series of internal standard solutions with known concentrations: fix the weight of the internal standard at 20 mg, and set the weights of cyclopentadienyltris(dimethylamino)zirconium to 5 mg, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, and 35 mg, respectively. 2. Perform NMR analysis on these solutions and samples simultaneously, and record the peak area or peak height of the internal standard and the target substance; 3. Establish an internal standard calibration curve based on the response ratio of the internal standard to the target substance.

[0059] After the improvement, for samples of any concentration, only 20 mg of internal standard needs to be added, and any weight of sample within the range of 5-35 mg can be selected. The specific concentration of the sample can then be determined through the internal standard calibration curve. Furthermore, by comparing the internal standard calibration curves obtained by adding different anhydrous internal standards, it was found that when anhydrous toluene is used as the internal standard, the curve stability is better, with an R² value exceeding 0.99. The stability of the calibration curve is significantly better than that of anhydrous tetrahydrofuran solvent.

Claims

1. A method for measuring the purity of metal-based precursors using the internal standard method, characterized in that, Includes the following steps: Step 1: Weigh the sample and anhydrous internal standard into the same EP tube, add deuterated reagent to dissolve, and after the sample and internal standard are fully dissolved, transfer to an NMR tube for instrument testing; Step Two: On-computer experiment and parameter settings; Step 3: Establish the internal standard calibration curve: Perform NMR analysis on the internal standard and the sample simultaneously, and record the peak area or peak height of the internal standard and the target substance; establish an internal standard calibration curve based on the response ratio between the internal standard and the target substance; then add 20 mg of internal standard when measuring any concentration of sample, select any weight of sample from 5 mg to 35 mg, and the specific concentration of the sample can be obtained through the internal standard calibration curve. The formula for the internal standard calibration curve is as follows: S 产 : The integral of the 1H NMR spectrum of the CpZr addition amount; S 内 : The integral of the 1H NMR spectrum of the amount of internal standard added; m 产 : The weight added by CpZr; m 内 : Weight added to the internal standard; C 产 Concentration of CpZr products; C 内 : Concentration of internal standard.

2. The method for measuring the purity of metal-based precursors using the internal standard method according to claim 1, characterized in that: The deuterated reagent is any one of deuterated benzene, deuterated DMSO, deuterated tetrahydrofuran, and deuterated acetone; the internal standard is toluene, 1,3,5-trimethoxybenzene, and o-xylene.

3. The method for measuring the purity of metal-based precursors using the internal standard method according to claim 1, characterized in that: The deuterated reagent is deuterated benzene, and the internal standard is toluene reagent.

4. The method for measuring the purity of metal-based precursors using the internal standard method according to claim 3, characterized in that: The internal standard is dehydrated to obtain an anhydrous internal standard. The method for processing the anhydrous internal standard is as follows: the 5A molecular sieve is dried in a drying oven for 20-24 hours, and then the reagent is soaked in a glove box for 20-24 hours to make the reagent moisture content less than 1 ppm, thus obtaining an anhydrous internal standard.

5. The method for measuring the purity of metal-based precursors using the internal standard method according to claim 4, characterized in that: The purity of the samples and internal standards is above 99%, and they are of analytical or chromatographic purity.

6. The method for measuring the purity of metal-based precursors using the internal standard method according to claim 1, characterized in that: The sample is cyclopentadienyl tris(dimethylamino)zirconium, cyclopentadienyl tris(dimethylamino)hafnium, tetra(dimethylamino)zirconium or tetra(dimethylamino)hafnium.

7. The method for measuring the purity of metal-based precursors using the internal standard method according to claim 1, characterized in that: The sample mass is 5-35 mg, and the anhydrous internal standard is 10-20 mg.

8. The method for measuring the purity of metal-based precursors using the internal standard method according to claim 1, characterized in that: In the NMR parameter settings, the number of scans (NS) is 64 or more. The excitation center O1P is located between the sample peak and the internal standard peak; The relaxation delay time D1 is 15s or more.

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