CN115656309A - Method for rapidly reducing Hf memory effect in ICP-MS (inductively coupled plasma-mass spectrometry) determination - Google Patents

Abstract

The invention discloses a method for quickly reducing Hf memory effect in ICP-MS (inductively coupled plasma-mass spectrometry) determination, which comprises the following steps of: using HF solution, HF and HNO ₃ Mixed solution, HF and H ₂ O ₂ Cleaning the sample injection system by the mixed solution in sequence, and repeating the cleaning step until the Hf element signal is reduced to a required value; the concentration of the HF solution is 2% -5%, and the HF and the HNO are ₃ The concentration of each component in the mixed solution is 2% -5%, and the HF and the H are ₂ O ₂ The concentration of HF in the mixed solution is 2% -5%, H ₂ O ₂ The concentration of (2) is 20-40%. According to the strength of the adsorption capacity of the Hf residues in the ICP-MS sample injection system, different solutions are adopted for sequentially washing, the washing 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 measurement is effectively reduced, and the ICP-MS detection of Hf and Yb, lu, ta, W, rb, sr, Y and Z interfered by Hf are improvedThe accuracy of the content of r, ba and other elements.

Description

Method for rapidly reducing Hf memory effect in ICP-MS (inductively coupled plasma-mass spectrometry) determination

Technical Field

The invention relates to the technical field of ICP-MS (inductively coupled plasma-mass spectrometry) determination, in particular to a method for quickly reducing Hf memory effect in ICP-MS determination.

Background

With the development of semiconductor technology, the integration level of chips is continuously improved, the size of devices is continuously reduced, and the requirements on electronic materials are higher and higher, especially in the fields of coating, photoresist and the like. Atomic layer deposition(ALD) is a thin film forming technique using successive chemical reactions in a gas phase, capable of precisely controlling a film thickness at an atomic layer level, and producing a thin film having high purity, uniformity, and good maintenance, and thus is receiving attention. Impurity control in ALD sources is particularly important because the purity of ALD sources has a significant impact on the coating. The ALD sources are various in types, and the biggest difficulty in the purity detection process is that the substrate of the ALD source is metal organic matter, and high-concentration substrate metal is certainly introduced during ICP-MS detection, and the substrate metal can remain in the atomizing chamber, the connecting pipe, the rectangular pipe, the truncated cone, the sampling cone, the lens and the like of the ICP-MS to form a memory effect, and can form interference when analyzing the next sample to influence quantitative analysis of partial elements, such as the memory effect of Hf: hf (hafnium) ⁺⁺ (180)---Zr ⁺ (90)，Hf ⁺ 、HfH ⁺ (180、181)---Ta ⁺ (180、181)。

The memory effect of hafnium (Hf) in ICP-MS has been a difficult problem in analysis, and the conventional cleaning method has no good effect on the memory effect of Hf. At present, the cleaning of Hf adsorbed in an ICP-MS sample injection system is mainly carried out through the following steps: (1) The atomizing chamber with ICP-MS removed is rinsed with ultrapure water, the torch is removed and placed at 5% HNO ₃ Soaking in the solution for 24 hours, washing with ultrapure water, blow-drying, finally detaching the intercepting cone, wiping the sampling cone with an alumina powder solution, washing with ultrapure water, and blow-drying; (2) After the disassembled atomizing chamber, torch tube, cutting cone and sampling cone are installed, the instrument is started and the content of HNO is 3% -5% ₃ The solution cleaned the Hf adsorbed in the ICP-MS sample injection system, but there was no significant change in Hf remaining in the ICP-MS sample injection system after 2 hours of cleaning. Therefore, the current processing technology has no effect on removing the memory effect of Hf, and a special ICP-MS is required to be equipped for determining the Hf source, which causes resource waste. Therefore, a method for rapidly reducing the Hf memory effect in ICP-MS measurement is needed to improve the accuracy and detection efficiency of ICP-MS.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for quickly reducing the memory effect of Hf in ICP-MS (inductively coupled plasma-mass spectrometry), wherein Hf shows a strong memory effect, is difficult to elute from a sample injection system of the ICP-MS, and the conventional cleaning method has long time and poor effect.

In order to solve the technical problems, the invention provides the following technical scheme:

the invention provides a method for rapidly reducing Hf memory effect in ICP-MS (inductively coupled plasma-mass spectrometry) determination, which comprises the following steps:

(1) Using HF solution, HF and HNO ₃ Mixed solution, HF and H ₂ O ₂ Cleaning the ICP-MS sample injection system by the mixed solution in sequence; the concentration of the HF solution is 2% -5%, and the HF and the HNO are ₃ The concentration of each component in the mixed solution is 2% -5%, and the HF and the H are ₂ O ₂ The concentration of HF in the mixed solution is 2% -5%, H ₂ O ₂ The concentration of (A) is 20-40%;

(2) And monitoring the signal value of the Hf element in the cleaning process, and repeating the cleaning step until the signal value of the Hf element is reduced to the required value.

According to the method, different solutions are adopted to clean an ICP-MS sample injection system in sequence according to the strength of the adsorption capacity of residues in the system and the difference of the concentration of the residues, firstly, HF solution with the concentration of 2% -5% is adopted to dissolve a large amount of Hf adsorbed in the sample injection system, and an Hf oxide film protection layer is damaged; then adopting HF and HNO ₃ The mixed solution further dissolves Hf ions adsorbed in the sample injection system, and dissolves and washes out and separates a small amount of Hf-containing chloride (usually, a certain amount of hafnium tetrachloride remains in the ALD hafnium precursor source) remaining in the sample injection system; further using HF and H ₂ O ₂ The mixed solution dissolves and washes the non-eluted Hf-containing nitride in the sample injection system, so as to achieve the effect of deeply removing Hf in the sample injection system. The process needs to prepare a cleaning solution with proper concentration to achieve the elution effect and avoid damaging the system.

Further, in the testing stage of the Hf-containing sample, a mixed solution of nitric acid and hydrofluoric acid is adopted as a medium of the Hf-containing sample; the nitric acid and the hydrofluoric acid both adopt electronic grade solvents, and the impurity content is less than or equal to 100ppt.

Further, the Hf-containing sample is a hafnium precursor source for use in atomic deposition techniques, the hafnium precursor source being tetrakis (dimethylamino) hafnium, tetrakis (ethylmethylamino) hafnium, tetrakis (diethylamino) hafnium, or tris (dimethylamino) cyclopentadienyl hafnium.

Further, in the step (1), HF solution, HF and HNO are adopted ₃ Mixed solution, HF and H ₂ O ₂ The mixed solution is washed for 10-15 minutes in sequence.

Further, in the step (1), the HF solution is prepared by adopting ultrapure hydrofluoric acid and ultrapure water, and the HF and the HNO are ₃ The mixed solution is prepared from ultrapure hydrofluoric acid, ultrapure nitric acid and ultrapure water, wherein the HF and the H are ₂ O ₂ The mixed solution is prepared by adopting ultrapure hydrofluoric acid, ultrapure hydrogen peroxide and ultrapure water.

Furthermore, the impurity content in the ultrapure hydrofluoric acid, the ultrapure nitric acid and the ultrapure hydrogen peroxide is less than or equal to 100ppt.

Further, in the step (1), the concentration of the HF solution is 3%, and the HF and the HNO are mixed ₃ The concentration of each component in the mixed solution is 3 percent, and the HF and the H are ₂ O ₂ The concentration of HF in the mixed solution was 3% and H ₂ O ₂ The concentration of (2) is 30%.

Furthermore, before cleaning the ICP-MS sample injection system, the atomization chamber of the ICP-MS is detached, ultrapure water is adopted to flush the atomization chamber, and the atomized liquid is installed on the ICP-MS after flushing. And cleaning the residual solution in the atomizing chamber.

Further, in step (2), the Hf elemental signal value is briefly measured in the helium tuning mode.

Further, the method also comprises a process of finally adopting ultrapure water for cleaning; after the sample injection system is washed by adopting the acidic and strong oxidizing solution, in order to avoid damage to the instrument caused by the residual cleaning solution and further remove a small amount of cleaning solution remained in the sample injection system for dissolving Hf ions, the system is washed for not less than 10 minutes by adopting ultrapure water, so that the residue of the Hf ions is reduced, and a certain protection effect is exerted on the instrument.

Further, the invention adopts HF solution, HF and HNO ₃ Mixed solution, HF and H ₂ O ₂ Cleaning the sample injection system with the mixed solution, but not limited to, sequentially adopting HF solution, HF and HNO ₃ Mixed solution, HF and H ₂ O ₂ The sequence of washing the mixed solution is verified by experiments that HF solution, HF and HNO are adopted in sequence ₃ Mixed solution, HF and H ₂ O ₂ The effect of washing by the mixed solution is optimal.

Further, the required value is 0 to 50cps; when the background value of the instrument is less than 50cps, the detection of other samples cannot be interfered.

The invention has the beneficial effects that:

according to the method, different cleaning liquids are adopted to clean the sample injection system in sequence according to the strength of the adsorption capacity of different Hf-containing residues in the ICP-MS sample injection system, instrument components such as instrument lenses, four-stage rods and the like are not required to be disassembled, the cleaning process is simple and easy to monitor, hf in the sample injection system can be rapidly removed in a short time, the memory effect of Hf in ICP-MS measurement is effectively reduced, the accuracy of detecting Hf and the contents of Yb, lu, ta, W, rb, sr, Y, zr, ba and other elements interfered by Hf by ICP-MS is improved, and meanwhile the detection efficiency of ICP-MS is improved.

Drawings

FIG. 1 is a graph of Hf residue in the instrument after batch processing in example 1;

FIG. 2 is the Hf residue in the instrument after 10 minutes of washing with solution A in example 1;

FIG. 3 is the Hf residue in the instrument after 10 minutes of cleaning with mixed solution B in example 1;

FIG. 4 is a graph showing Hf residue in the instrument after 10 minutes of washing with the mixed solution C in example 1;

FIG. 5 shows Hf residue in the instrument after 10 minutes of ultrapure water cleaning in example 1;

FIG. 6 is the Hf residue in the instrument after batch processing in example 2;

FIG. 7 shows Hf residue in the instrument after one hour of HF washing with 3% in example 2;

FIG. 8 shows Hf residue in the apparatus after each 10-minute cleaning in example 2 using solution A, mixed solution B, mixed solution C and ultrapure water in this order;

FIG. 9 is Hf residue in the batch post treatment instrument of comparative example 1;

FIG. 10 shows the content of HNO in comparative example 1 after 3% ₃ Hf residue in the instrument was left after 1h of solution washing.

Detailed Description

The present invention is further described below in conjunction with the drawings and the embodiments so that those skilled in the art can better understand the present invention and can carry out the present invention, but the embodiments are not to be construed as limiting the present invention.

Unless defined otherwise, 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 invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Example 1

This example relates to ICP-MS testing for hafnium tetra (dimethylamino) and removing memory effect of Hf in ICP-MS measurement after the test, and the specific operations are as follows:

(1) Weighing 0.1g of tetradimethylamino hafnium in an inert atmosphere, adding 8mL of electronic nitric acid and 0.5mL of electronic hydrofluoric acid into a PTFE digestion tank, taking four groups of parallel samples, and adding 8mL of electronic nitric acid and 0.5mL of electronic hydrofluoric acid into an empty digestion tank to serve as a blank reference.

(2) Putting the digestion tank into a microwave digestion instrument, and setting a temperature-raising program as follows: keeping the temperature at 120 deg.C for 5min, keeping the temperature at 140 deg.C for 5min, keeping the temperature at 160 deg.C for 5min, keeping the temperature at 180 deg.C for 5min, keeping the temperature at 200 deg.C for 5min, and keeping the temperature at 220 deg.C for 5min.

(3) After digestion is finished, the sample is cooled and then is moved into a peeled PFA sample bottle, and water is added to the sample bottle to reach a constant volume of 100g. Control blanks were also treated as well.

(4) The ICP-MS was turned on, stabilized for 30 minutes, the instrument tuned, and a batch process was established using standard addition methods, as follows:

(5) After the batch processing, the signal monitoring of the open element looks for the residue of Hf, which is much remained in ICP-MS.

The method for cleaning the Hf residual in the ICP-MS sample injection system respectively adopts a conventional cleaning method and the method of the invention, and comprises the following steps:

preparing a cleaning solution:

preparing a solution A: preparing a 3% HF solution by adding ultrapure water into purchased electronic grade HF (TAMAPicture AA-100 ultrapure hydrofluoric acid, impurities less than or equal to 100ppt and concentration of 38%);

preparing a mixed solution B: using purchased electronic grade HF and electronic grade HNO ₃ (TAMApure AA-100 ultrapure nitric acid, impurities. Ltoreq.100 ppt, concentration 55%) 3% by weight of HF and 3% by weight of HNO ₃ The mixed solution of (1);

preparing a mixed solution C: using purchased electronic grade HF and electronic grade H ₂ O ₂ (TAMApure AA-100 hydrogen peroxide, impurity not more than 100ppt, concentration 55%) was added with ultrapure water to prepare 30% by weight ₂ O ₂ And 3% of an HF mixed solution.

Cleaning: the signal for Hf before cleaning is 4702cps as shown in FIG. 1. Sequentially adopting the prepared solution A, the mixed solution B, the mixed solution C and ultrapure water to clean for 10 minutes respectively; after washing for 10 minutes with the prepared solution A, the signal of Hf is observed to be 2204cps (shown in figure 2), after washing for 10 minutes with the prepared mixed solution B, the signal of Hf is observed to be 1478.8cps (shown in figure 3), after washing for 10 minutes with the prepared mixed solution C, the signal of Hf is observed to be 741cps (shown in figure 4), and finally, after washing for 10 minutes with ultrapure water, as shown in figure 5, the signal of Hf in the instrument is reduced to 20.6cps, and the residual content does not interfere with the analysis of other types of samples, namely the memory effect of Hf in the instrument is effectively removed.

Example 2

This example relates to the ICP-MS testing of hafnium tetra (ethylmethylamino) salt and different cleaning methods were used to remove Hf remaining in the ICP-MS instrument after the test, as follows:

(1) Weighing 0.05g of tetraethyl methyl amino hafnium in an inert atmosphere, adding 5mL of electronic nitric acid and 0.3mL of electronic hydrofluoric acid into a PTFE digestion tank, taking four groups of parallel samples, and adding 5mL of electronic nitric acid and 0.3mL of electronic hydrofluoric acid into an empty digestion tank to serve as a control blank.

(2) Placing the weighed digestion tank with an opening on a graphite acid dispelling instrument, and placing the digestion tank into a fume hood. The temperature of the graphite acid-expelling instrument is set to 240 ℃, and the heating time is 300min.

(3) After acid expelling is finished, the sample is cooled and then is taken into a peeled PFA sample bottle, and 0.5 percent electronic grade nitric acid is added to the sample bottle to ensure that the volume is 100g.

(4) The ICP-MS was turned on, stabilized for 30 minutes, the instrument tuned, and the batch set up was established using the external standard method, as shown in the following table:

mark liquid blank	0ppb
		Marking fluid 1	1ppb
Marking fluid 2	2ppb
		Marking liquid 3	3ppb
Control blank
		Sample 1
Sample 2
		Sample 3
Sample No. 4

(5) After the batch processing, the signal monitoring of the open element looks for the residue of Hf, which is much remained in ICP-MS.

The method for cleaning Hf residual in the ICP-MS sample injection system by respectively adopting single 3 percent HF solution and the method of the invention comprises the following steps:

preparing a cleaning solution:

preparing a solution A: preparing a 3% HF solution by adding ultrapure water into purchased electronic grade HF (TAMAPicture AA-100 ultrapure hydrofluoric acid, impurities less than or equal to 100ppt and concentration of 38%);

preparing a mixed solution B: using purchased electronic grade HF and electronic grade HNO ₃ Adding ultrapure water to prepare 3% of HF and 3% of HNO ₃ The mixed solution of (1);

preparing a mixed solution C: using purchased electronic grade HF and electronic grade H ₂ O ₂ (TAMApure AA-100 hydrogen peroxide, impurity not more than 100ppt, concentration 55%) was added with ultrapure water to prepare 30% by weight ₂ O ₂ And 3% of an HF mixed solution.

Cleaning:

single 3% hf solution wash: the signal for Hf before cleaning is 6037cps as shown in FIG. 6. The HF solution was used for cleaning at 3% for 1h, and as a result, the signal value of Hf was decreased from 6037cps to 2668.5cps as shown in FIG. 7.

After cleaning with the single 3% HF solution for 1h, the subsequent cleaning was carried out by the method of the present invention, i.e., using the prepared solution A, mixed solution B, mixed solution C and ultrapure water for 10 minutes, as shown in FIG. 8, the observed Hf signal was reduced to 34.8cps, the instrument background value was less than 50cps, the detection requirements were met, and no interference was caused to the detection of other samples.

Comparative example 1

This comparative example relates to ICP-MS testing for hafnium tetra (dimethylamino) and removing the memory effect of Hf in the ICP-MS assay after the test, and is performed as follows:

(1) Weighing 0.1g of tetradimethylamino hafnium in an inert atmosphere, adding 8mL of electronic nitric acid and 0.5mL of electronic hydrofluoric acid into a PTFE digestion tank, taking four groups of parallel samples, and adding 8mL of electronic nitric acid and 0.5mL of electronic hydrofluoric acid into an empty digestion tank to serve as a blank reference.

(2) Putting the digestion tank into a microwave digestion instrument, and setting a temperature rise program as follows: keeping the temperature at 120 deg.C for 5min, keeping the temperature at 140 deg.C for 5min, keeping the temperature at 160 deg.C for 5min, keeping the temperature at 180 deg.C for 5min, keeping the temperature at 200 deg.C for 5min, and keeping the temperature at 220 deg.C for 5min.

(3) After digestion, the sample is cooled and then is taken into a peeled PFA sample bottle, and water is added to the sample bottle to achieve a constant volume of 100g. Control blanks were also treated similarly.

(4) The ICP-MS was turned on, stabilized for 30 minutes, the instrument tuned, and a batch process was established using standard addition methods, as follows:

marking fluid 1	0ppb
		Marking liquid 2	1ppb
Marking liquid 3	2ppb
		Marking liquid 4	3ppb
Control blank
		Sample No. 1
Sample 2
		Sample 3
Sample No. 4

(5) After the batch processing of the instrument, the signal monitoring of the open element is used for checking the residue of Hf, and the memory effect of Hf is more remained in ICP-MS.

In the comparative example, the conventional cleaning method is respectively adopted to clean the residual Hf in the ICP-MS sample injection system, and the specific steps are as follows:

preparing a cleaning solution: using purchased electronic grade HNO ₃ (TAMApure AA-100 ultrapure nitric acid, impurity of not more than 100ppt, concentration of 55%) and ultrapure water 3% HNO ₃ A solution;

cleaning: the signal for Hf before cleaning is 5731.9cps as shown in FIG. 9. By 3% of HNO ₃ The solution was washed for 1h, and the signal value of Hf was reduced from 5731.9cps to 5082.3cps as shown in FIG. 10.

Comparative example 1 and example 1, hf remaining in the ICP-MS sample injection system after the same substance was detected was cleaned, comparative example 1 was a conventional cleaning method, and example 1 was a method according to the present invention, that is, each cleaning was performed for 10 minutes using the prepared solution a, mixed solution B, mixed solution C, and ultrapure water. As is clear from the cleaning effects of comparative example 1 and comparative example 1, comparative example 1 adopted a single 3% HNO ₃ The solution cleans the system for a long time, the concentration of Hf in the sample introduction system is almost unchanged, the cleaning efficiency is low, and the effect is poor, but the cleaning method of the embodiment 1 is adopted to clean, so that Hf in the system can be reduced to below 50cps in a short time, and the requirements of other sample detection are met.

As can be seen from the above examples and comparative examples, the method for reducing Hf memory effect in ICP-MS measurement of the invention can rapidly and efficiently remove Hf remained in the instrument by different Hf-containing compounds, greatly improves the efficiency of daily detection compared with the conventional cleaning method, and after one round of washing, the count of Hf remained in the instrument is less than 50cps, which does not interfere with the analysis of other types of samples, and greatly improves the accuracy of ICP-MS.

The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitutions or changes made by the person skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the invention is subject to the claims.

Claims (10)

1. A method for rapidly reducing Hf memory effect in ICP-MS measurement is characterized by comprising the following steps:

(1) Using HF solution, HF and HNO ₃ Mixed solution, HF and H ₂ O ₂ Cleaning an ICP-MS sample injection system by the mixed solution in sequence; the concentration of the HF solution is 2% -5%, and the HF and the HNO are ₃ The concentration of each component in the mixed solution is 2% -5%, and the HF and the H are ₂ O ₂ The concentration of HF in the mixed solution is 2% -5%, H ₂ O ₂ The concentration of (A) is 20-40%;

(2) And monitoring the signal value of the Hf element in the cleaning process, and repeating the cleaning step until the signal value of the Hf element is reduced to the required value.

2. The method of claim 1, wherein a mixed solution of nitric acid and hydrofluoric acid is used as a medium for the Hf containing sample during the Hf containing sample testing stage.

3. The method of claim 2, wherein the Hf-containing sample is a hafnium precursor source for use in atomic deposition techniques, the hafnium precursor source being tetrakis (dimethylamino) hafnium, tetrakis (ethylmethylamino) hafnium, tetrakis (diethylamino) hafnium, or tris (dimethylamino) cyclopentadienyl hafnium.

4. The method according to claim 1, wherein in step (1), HF solution, HF and HNO are used ₃ Mixed solution, HF and H ₂ O ₂ The mixed solution is washed for 10-15 minutes in sequence.

5. The method according to claim 1, wherein in the step (1), the HF solution is prepared by using ultrapure hydrofluoric acid and ultrapure water, and the HF and HNO are added ₃ The mixed solution is prepared from ultrapure hydrofluoric acid, ultrapure nitric acid and ultrapure water, wherein the HF and the H are ₂ O ₂ The mixed solution is prepared by adopting ultrapure hydrofluoric acid, ultrapure hydrogen peroxide and ultrapure water.

6. The method of claim 2, wherein the ultrapure hydrofluoric acid, ultrapure nitric acid and ultrapure hydrogen peroxide have an impurity level of 100ppt or less.

7. The method according to claim 1, wherein the concentration of the HF solution in step (1) is 3%, and the HF and HNO are mixed ₃ The concentration of each component in the mixed solution is 3 percent, soHF and H ₂ O ₂ The concentration of HF in the mixed solution was 3% and H ₂ O ₂ The concentration of (2) is 30%.

8. The method according to claim 1, wherein before cleaning the ICP-MS sampling system, the atomizing chamber of the ICP-MS is detached, the atomizing chamber is washed by ultrapure water, and the ICP-MS is mounted after washing.

9. The method of claim 1, wherein in step (2), the Hf elemental signal value is monitored in a helium tuning mode.

10. The method as claimed in claim 1, further comprising a final rinsing process with ultrapure water, wherein the rinsing process with ultrapure water is not less than 10 minutes.

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