Method for rapidly and efficiently detecting boron impurities in trichlorosilane

Abstract

The invention provides a method for rapidly and efficiently detecting boron impurities in trichlorosilane, and belongs to the technical field of analytical chemistry. In order to overcome the defects that in the prior art, GB / T 28654 standard pretreatment is tedious, consumed time is long, and boron element loss is prone to occurring, the method comprises the steps that under the condition of 0-4 DEG C, a sample is dissolved with 0.5-1.0% of dilute hydrofluoric acid and then diluted with dilute nitric acid smaller than or equal to 1.0%, and a chemical high-resolution multiple quadrupole inductively coupled plasma mass spectrometer is adopted for detection. The method is high in precision and accuracy, samples with different concentrations are determined in parallel for 6 times, RSD is less than or equal to 10%, deviation between a result and a standard value is less than or equal to 10%, adding standard recovery rate is 95-105%, and the method is suitable for rapid and efficient detection of boron impurities in chlorosilane industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of analytical chemistry detection, and particularly relates to a method for trace detection of boron element in trichlorosilane based on inductively coupled plasma mass spectrometry (ICP-MS), which is particularly suitable for rapid and accurate analysis of high-purity trichlorosilane samples in industrial production scenarios. Background Art

[0002] Trichlorosilane (SiHCl3), as the core raw material of polysilicon and silane coupling agents, its purity directly affects the quality of downstream products. Boron (B), as a typical impurity element, even at extremely low content (ppb level), will significantly reduce the stability of the performance of semiconductor devices. However, the existing detection technologies have the following defects:

[0003] 1. Complicated traditional pretreatment: The GB / T28654 standard adopts a multi-step extraction-distillation method, which takes a long time (>4h / batch), and due to the volatility of BF3 (boiling point -100.3°C) and the formation of siloxane intermediates, the recovery rate of boron element is <85%. During the distillation process, the residue of silicon powder particle size (0.18 - 0.12mm) and catalyst (Cu-Ag-Mg alloy) will exacerbate the gasification loss of boron complexes;

[0004] 2. Insufficient detection sensitivity: The detection limit of the conventional ICP-OES method (RSD = 3.5%) is 1.0ppb, while the boron content requirement for electronic-grade trichlorosilane used in power semiconductors is ≤0.1ppb (GB / T30652 - 2023 11N grade standard), which cannot meet the detection requirements of high-purity trichlorosilane required for power devices;

[0005] 3. Severe matrix interference: By-products such as SiO2 and SiF4 generated by the decomposition of trichlorosilane in the presence of water easily contaminate the mass spectrometry system, resulting in signal drift. Summary of the Invention

[0006] The purpose of this part is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this part, as well as in the abstract and title of the specification of this application, to avoid obscuring the purpose of this part, the abstract, and the title, but such simplifications or omissions cannot be used to limit the scope of the present invention.

[0007] In view of the above and / or problems existing in the prior art, the present invention is proposed. The detection method provided by the present invention can rapidly and accurately determine the boron element in trichlorosilane.

[0008] Therefore, the purpose of the present invention is to provide a rapid and efficient detection method for boron impurities in trichlorosilane, including,

[0009] (1) Sample dissolution: Under low-temperature conditions, using dilute hydrofluoric acid as the dissolution solvent, dissolve the trichlorosilane sample;

[0010] (2) Sample dilution: Dilute the sample after the dissolution treatment;

[0011] (3) Preparation of standard solutions: Using the sample treated in step (2) as the base, prepare a series of standard solutions; the series of standard solutions are obtained by adding a 1 mg / L boron standard solution to obtain the required gradient concentrations;

[0012] (4) Establishment of the standard curve: Use a high-resolution chemical multiquadrupole inductively coupled plasma mass spectrometer, and use the standard addition method to detect the series of standard solutions to obtain the corresponding ICP-MS detection values, and based on this, establish a regression equation for boron ions. The correlation coefficient R of the regression equation 2 should be greater than 99.99%;

[0013] (5) Determination of the sample content: After the sample to be tested is treated in steps (1) to (4), calculate the content of boron element in the trichlorosilane sample.

[0014] As a preferred embodiment of the rapid and efficient detection method for boron impurities in trichlorosilane according to the present invention, wherein: the low-temperature condition is 0 to 4 °C.

[0015] As a preferred embodiment of the rapid and efficient detection method for boron impurities in trichlorosilane according to the present invention, wherein: the concentration of the dilute hydrofluoric acid is 0.5 to 1%.

[0016] As a preferred embodiment of the rapid and efficient detection method for boron impurities in trichlorosilane according to the present invention, wherein: the concentration of the dilute nitric acid is 0.1 to 0.5%.

[0017] As a preferred embodiment of the rapid and efficient detection method for boron impurities in trichlorosilane according to the present invention, wherein: the dosage ratio of the sample to the dissolution solvent is 1:10, and the dissolution treatment is carried out in a container made of clean PFA bottle material.

[0018] As a preferred embodiment of the rapid and efficient detection method for boron impurities in trichlorosilane according to the present invention, wherein: the detection conditions of the high-resolution chemical multiquadrupole inductively coupled plasma mass spectrometer include:

[0019] (i) The nebulizer, spray chamber, and torch tube are all made of hydrogen fluoride-resistant materials, and the central tube material is 1.5 mm platinum;

[0020] (ii) The RF power is 1000 to 1500 W;

[0021] (iii) The plasma flow rate is 13 to 16 L / min;

[0022] (iv) The atomizing gas flow rate is 0.7 - 1.0 L / min;

[0023] (v) The compensating gas flow rate is 0.9 - 1.30 L / min;

[0024] (vi) The sample introduction speed is 15 - 25 rpm;

[0025] (vii) Scanning mode: Q3 Only;

[0026] (viii) Q3 mass number: 11.0093;

[0027] (viiii) IGM Focusing;

[0028] (x) RPQ: 0.25 - 0.80.

[0029] As a preferred embodiment of the rapid and efficient detection method for boron impurities in trichlorosilane according to the present invention, wherein: in the preparation of the series of standard solutions, ultrapure water is used for dilution during the preparation process.

[0030] As a preferred embodiment of the rapid and efficient detection method for boron impurities in trichlorosilane according to the present invention, wherein: before ICP-MS detection, matrix matching treatment is performed on the sample to be tested and the standard solution.

[0031] As a preferred embodiment of the rapid and efficient detection method for boron impurities in trichlorosilane according to the present invention, wherein: the detection limit of the boron element is ≤1 ppb, and the relative standard deviation RSD of the detection result is ≤10%.

[0032] As a preferred embodiment of the rapid and efficient detection method for boron impurities in trichlorosilane according to the present invention, wherein: the method further includes daily calibration and maintenance of the detection instrument.

[0033] Advantages of the present invention:

[0034] (1) Lower detection limit: The detection limit of the method of the present invention is less than 0.4 ppb, which is better than the GB / T 28654 extraction method (0.5 - 2 ppb) and the ICP-OES direct injection method (1.0 ppb), and can detect boron elements at lower concentrations.

[0035] (2) Shorter pretreatment time: Only 0.2 hours, which is much lower than the GB / T 28654 extraction method (4 - 6 hours) and the ICP-OES direct injection method (1 hour), significantly improving the detection efficiency.

[0036] (3) Higher boron recovery rate: reaching 90 - 110%, superior to the extraction method in GB / T 28654 (75 - 85%) and the ICP-OES direct injection method (60 - 70%), with more accurate and reliable detection results. Detailed implementation manners

[0037] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention in conjunction with the embodiments of the specification.

[0038] In the following description, many specific details are set forth to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0039] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that can be included in at least one implementation manner of the present invention. The "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selectively exclusive embodiment from other embodiments.

[0040] The present invention provides a rapid and efficient detection method for boron impurities in trichlorosilane, specifically including the following steps:

[0041] Step 1: Pretreatment of the sample

[0042] 1. Preparation of the dissolution solvent

[0043] Accurately pipette 10 mL of HF with a concentration of 0.5 - 1%. After weighing, place it in an ice-water bath at 0 - 4°C and pre-cool for 10 minutes for standby. The weight of 10 mL of 0.5 - 1% HF is denoted as A.

[0044] 2. Dissolution of the sample

[0045] Use a pipette to slowly add 1.0 mL of the trichlorosilane sample to be measured (about 1.0 g, accurate to 0.0001 g) into a 100 mL PFA bottle containing 10 g of hydrofluoric acid, and gently shake it in an ice-water mixed bath until a stable and uniform solution is formed. Then weigh the solution, and the weight of the added 1.0 mL of the sample to be measured is denoted as B.

[0046] 3. Dilution of the sample

[0047] Dilute the above-dissolved sample to an appropriate multiple with <1% HNO3 according to the actual situation, and the dilution multiple is denoted as C.

[0048] 4. Preparation of the blank sample

[0049] Synchronously prepare a sample blank according to the above steps, but do not add trichlorosilane sample.

[0050] Step 2: Detection condition setting and instrument optimization

[0051] 1. Detection condition setting

[0052] The nebulizer, spray chamber, and torch tube (the central tube is made of 1.5 mm platinum) are all made of hydrogen fluoride-resistant materials. The preferred parameters for the inductively coupled plasma mass spectrometry detection conditions are as follows: RF power: 1000 - 1500 W; plasma flow rate: 13 - 16 L·min -1 ; nebulizer gas flow rate: 0.7 - 1.0 L·min -1 ; compensation gas flow rate: 0.9 - 1.30 L·min -1 ; sample introduction speed: 15 - 25 rpm; Scan Mode: Q3 Only; Q3 Mass: 11.0093; IGM (Ion Guide Mode) Focusing; RPQ (Resolution / Pressure Quadrupole): 0.25 - 0.80.

[0053] 2. Instrument optimization

[0054] Before using a chemical high-resolution multi-quadrupole inductively coupled plasma mass spectrometer (PE5000G) for detection, it is necessary to tune the position of the torch tube of the instrument, the flow rate of the nebulizer gas, the hypercone voltage, the OmniRing voltage, the resolution of the mass axis, and the position of the mass axis with a tuning solution of 200 ng / L of 6.940Li, 9.012Be, 23.98Mg, 55.935Fe, 114.904In, 207.977Pb, 238.05U. When the sensitivity of 9.012Be is greater than 2500, the sensitivity of 114.904In is greater than 90000, the sensitivity of 238.05U is greater than 55000, and the resolution is within the range of 0.78 ± 0.03 amu, and the relative standard deviation (RSD) of oxide and double-charged ions is within 0.03, then the standard curve can be made.

[0055] Step 3: Drawing of the working curve and detection of the sample

[0056] In the test solution to be measured after sample treatment, add 0.01 mL, 0.05 mL, 0.1 mL, 1 mL, and 10 mL of 1 mg / L boron standard solution respectively, and the corresponding spiked concentrations are 0.01 ppb, 0.05 ppb, 0.1 ppb, 1 ppb, and 10 ppb. By measuring the signal intensity after spiking, draw the standard curve and extrapolate to calculate the boron content in the sample to be measured, R2 ≥0.999; Calculate the concentration of the element to be measured using Equation 1.

[0057]

[0058] Wherein, A is the amount of trichlorosilane sample (g); B is the weight of 0.5% - 1% hydrofluoric acid (g); C is the dilution factor of 1% HNO3 (g); C S is the concentration of the solution to be measured (ppb); C0 is the concentration of the blank solution (ppb).

[0059] Step 4: Equipment and reagent specifications

[0060] 1. Equipment: Inductively coupled plasma mass spectrometer with a chemically high-resolution multiple quadrupole (PE5000G, PerkinElmer).

[0061] Analytical balance (range 0 - 300.0000 g, Shimadzu).

[0062] Ultra-pure water machine (resistivity ≥ 18.2 MΩ·cm, 25 °C, Millipore).

[0063] Pipette (range 100 - 1000 μL, 10 - 100 μL, Eppendorf).

[0064] 2. Reagents and gases:

[0065] Tuning solution of 6.940Li, 9.012Be, 23.98Mg, 55.935Fe, 114.904In, 207.977Pb, 238.05U at 200 ng / L (PerkinElmer).

[0066] Ultra-pure water (resistivity ≥ 18.2 MΩ·cm, 25 °C).

[0067] B standard solution: Agilent multi-element calibration standard - 4 (10 mg / L B, Ge, M O , Nb, P, Re, S, Si, Ta, Ti, W, Zr; HNO / trace HF matrix)

[0068] Hydrofluoric acid: concentration 38.0% ± 1.0 wt%, TAMAPURE-AA-10 grade.

[0069] Nitric acid: concentration 55.0% ± 1.0 wt%, TAMAPURE-AA-10 grade.

[0070] Argon (purity ≥ 99.999%).

[0071] Example 1

[0072] 1. Preparation of solutions

[0073] 1) 1 mg / L boron standard solution: Dilute the boron standard sample (Agilent multi - element calibration standard ~4 (10 mg / L B, Ge, M O , Nb, P, Re, S, Si, Ta, Ti, W, Zr; HNO3 / trace HF matrix)) to 1 mg / L with 1% nitric acid.

[0074] 2) 0.5% hydrofluoric acid solution: Dilute hydrofluoric acid (38.0% ± 1.0 wt%, TAMAPURE - AA - 10) to 0.5% with ultrapure water.

[0075] 3) 1.0% nitric acid solution: Dilute nitric acid (55.0% ± 1.0 wt%, TAMAPURE - AA - 10) to 1.0% with ultrapure water.

[0076] 4) Test solution:

[0077] (a) Accurately pipette 10 mL of HF with a concentration of 0.5 - 1%. Weigh it and place it in an ice - water bath at 0 - 4°C for pre - cooling for 10 minutes for later use. The weight of 10 mL of 0.5 - 1% HF is denoted as A.

[0078] (b) Slowly add 1.0 mL of the test trichlorosilane sample (about 1.0 g, accurate to 0.0001 g) to a 100 mL PFA bottle containing 10 g of hydrofluoric acid. Gently shake to form a stable and homogeneous solution, and weigh it. The weight of the added 1.0 mL of the test trichlorosilane sample is denoted as B.

[0079] (c) Pipette 1.0 g of the solution (accurate to 0.0001 g) slowly into a clean 100 mL PFA bottle. After weighing, dilute it to 100 g (accurate to 0.0001 g) with 1.0% nitric acid and shake well to obtain the test solution.

[0080] (d) Sample blank solution: Perform synchronous blanks according to the above steps (a) - (c). The only difference from the preparation of the test solution is that the trichlorosilane sample is not added.

[0081] 2. Detection conditions for inductively coupled plasma mass spectrometry

[0082] Detection parameters: The nebulizer, spray chamber, and torch tube (central tube 1.5 mm Pt) are all made of materials resistant to hydrofluoric acid. The radio - frequency power is 1000 - 1500 W; the plasma flow rate is 13 - 16 L·min -1 ; the nebulizing gas flow rate is 0.7 - 1.0 L·min -1 ; the makeup gas flow rate is 0.9 - 1.30 L·min -1 ; the sample introduction speed is 15 - 25 rpm.

[0083] 3. Preparation of Standard Curve and Determination of Samples

[0084] Process trichlorosilane samples without detected boron element according to the aforementioned steps, and prepare standard solutions at different concentration levels with this solution as the base. Subsequently, use a high-resolution multi-quadrupole inductively coupled plasma mass spectrometer (model: PE5000G) for analysis, draw a standard curve by the standard addition method, and thus determine the boron content in the solution to be measured. At the same time, with 1% nitric acid as the base, prepare a series of standard solutions with the same concentration as the trichlorosilane standard solution, also detect them using ICP-MS, and establish a standard curve by the standard addition method to determine the boron content in the sample blank.

[0085] 4. Detection Limit

[0086] 1) Process trichlorosilane samples without detected boron according to the preparation method of the solution to be measured, and then add 0.01 mL, 0.05 mL, 0.1 mL, 1.0 mL, 10 mL of boron standard solution (1 mg / L), that is, boron standard solutions with concentrations of 0.01 ppb, 0.05 ppb, 0.1 ppb, 1 ppb, 10 ppb. According to the detection conditions of the above inductively coupled plasma mass spectrometry and the method for making the standard curve, the linear correlation equation of boron element can be obtained.

[0087] 2) Instrument detection limit: Use the blank sample as the base to make the standard curve and determine the sample. Repeat the blank sample N times (N = 10) to obtain the instrument detection limit of boron element; Select trichlorosilane samples without detected boron, and repeat N times (N = 10) according to the method for making the standard curve and determining the sample to obtain the method detection line of boron element. The correlation coefficient, linear equation, instrument detection limit of the calibration curve of boron element and the detection line of the method are shown in Table 1 below.

[0088] Table 1 Linear Equation, Instrument Detection Limit and Method Detection Line

[0089]

[0090] Example 2

[0091] I. Precision and Accuracy Tests

[0092] Parallelly determine samples 1#, 2#, and 3# of trichlorosilane with boron contents of 4.02 ppb, 380.9 ppb, and 500.9 ppb respectively 6 times according to the conditions in Example 1, and the detection results are shown in Table 2.

[0093] Table 2 Precision and Accuracy of the Test Method for Boron Element in Trichlorosilane

[0094]

[0095]

[0096] As can be seen from Table 2, for the trichlorosilane samples of 1#, 2#, and 3#, the relative standard deviation RSD values of the measured values of boron element in 6 consecutive determinations are ≤10, and Er(%) ≤10%. The precision and accuracy of this method can meet the requirements of detection.

[0097] II. Spike recovery rate

[0098] 20 μL of 1 mg / L boron standard solution was added to the test solution of 1# trichlorosilane in Example 2, and 0.28 mL, 0.42 mL, and 10 mg / L boron standard solution were added to 2# and 3# respectively. The determination results were measured under the detection conditions of inductively coupled plasma mass spectrometry as shown in Table 3.

[0099] Table 3 Determination results of boron element spike recovery

[0100]

[0101] As can be seen from Table 3, the spike recovery rate of the actual sample of boron element is between 90-110%, and this method meets the test requirements.

[0102] Comparative Example 1

[0103] Six samples of trichlorosilane with boron element content of 4.02 ppb were prepared according to the test solution method in Example 1 at room temperature, and were denoted as A1, A2, A3, A4, A5, and A6 respectively, and ICP-MS sample determination was carried out. The difference from Example 2 is that the solution was prepared at room temperature, and the sample was directly added to 0.5% hydrofluoric acid at (22±2°C). The detection results of boron element in trichlorosilane at room temperature are shown in Table 4.

[0104] Table 4 Detection results of boron element in trichlorosilane at room temperature

[0105]

[0106] As can be seen from Table 4 above, the boron impurities in trichlorosilane measured at room temperature (22±2°C) are significantly low, and the reproducibility between parallel samples is poor.

[0107] The present invention provides a rapid and efficient detection method for boron impurities in trichlorosilane, and its innovation lies in:

[0108] 1. Low-temperature anti-interference dissolution system: The reaction temperature is controlled by an ice-water bath at 0-4°C, and 0.1-1% hydrofluoric acid (HF) is combined to achieve selective release of boron and inhibit the volatilization of boron-containing compounds such as BCl3 and B2H6;

[0109] 2. In-situ matrix matching technology: Using the sample solution after the same pretreatment as the dilution matrix to eliminate the suppression effect of the high-silicon matrix on the ICP-MS signal;

[0110] 3. High-sensitivity detection mode: Constructing a regression equation (R 2 ≥99.99%) by the standard addition method, combined with a torch made of HF-resistant material (Pt central tube 1.5 mm) and collision cell technology, to achieve a detection limit of 0.1 ppb level.

[0111] Compared with the existing GB / T 28654 extraction method and ICP-OES direct injection method, the method of the present invention shows significant advantages in the detection of boron element. In terms of the detection limit, the detection limit of the GB / T 28654 extraction method is 0.5 - 2 ppb, and that of the ICP-OES direct injection method is 1.0 ppb, while the detection limit of the method of the present invention is lower, less than 1.0 ppb, and can detect lower concentrations of boron element. In terms of the pretreatment time, the GB / T 28654 extraction method requires 4 - 6 hours, and although the ICP-OES direct injection method only requires 1 hour, the method of the present invention only requires 0.2 hours, greatly shortening the preparation time before detection and improving the detection efficiency. In terms of the boron recovery rate, the boron recovery rate of the GB / T 28654 extraction method is 75 - 85%, and that of the ICP-OES direct injection method is 60 - 70%, while the boron recovery rate of the method of the present invention is as high as 90 - 110%, and the accuracy and reliability of the detection results are higher. In summary, the method of the present invention is superior to the existing detection technologies in key indicators such as the detection limit, pretreatment time, and boron recovery rate.

[0112] The above are only the preferred embodiments of the present invention. It should be noted that without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also within the protection scope of the present invention.

Claims

1. A rapid and efficient detection method for boron impurities in trichlorosilane, characterized in that: including, (1) Sample dissolution: Under low-temperature conditions, using dilute hydrofluoric acid as the dissolution solvent, the trichlorosilane sample is dissolved; (2) Sample dilution: The sample after dissolution treatment is diluted; (3) Standard solution preparation: Using the sample treated in step (2) as the base, a series of standard solutions are prepared; The series of standard solutions are obtained by adding a 1 mg / L boron standard solution to obtain the required gradient concentrations; (4) Standard curve establishment: Using a chemical high-resolution multiquadrupole inductively coupled plasma mass spectrometer, the series of standard solutions are detected by the standard addition method to obtain the corresponding ICP-MS detection values, and a regression equation for boron ions is established based on this. The correlation coefficient R of the regression equation 2 should be greater than 99.99%; (5) Determination of sample content: After the sample to be measured is treated in steps (1) to (4), the content of boron element in the trichlorosilane sample is calculated and obtained.

2. The detection method according to claim 1, wherein: The low-temperature conditions are 0 - 4 °C.

3. The detection method according to claim 1, wherein: The concentration of the dilute hydrofluoric acid is 0.5 - 1%.

4. The detection method according to claim 1, wherein: The concentration of the dilute nitric acid is 0.1 - 0.5%.

5. The detection method according to claim 1, characterized in that: The dosage ratio of the sample to the dissolution solvent is 1:10, and the dissolution treatment is carried out in a container made of clean PFA bottle material.

6. The detection method according to claim 1, wherein: The detection conditions of the high-resolution multiple quadrupole inductively coupled plasma mass spectrometer include: (i) The nebulizer, spray chamber, and torch tube are all made of hydrogen fluoride-resistant materials, and the central tube material is 1.5 mm platinum; (ii) The RF power is 1000 - 1500 W; (iii) The plasma flow rate is 13 - 16 L / min; (iv) The nebulizing gas flow rate is 0.7 - 1.0 L / min; (v) The compensation gas flow rate is 0.9 - 1.30 L / min; (vi) The sample introduction speed is 15 - 25 rpm; (vii) Scanning mode: Q3 Only; (viii) Q3 mass number: 11.0093; (viiii) IGM Focusing; (x) RPQ: 0.25 - 0.

80.

7. The detection method according to claim 1, wherein: When preparing the series of standard solutions, ultra-pure water is used for dilution during the preparation process.

8. The detection method according to claim 1, characterized in that: Before ICP-MS detection, matrix matching treatment is performed on the sample to be measured and the standard solution.

9. The detection method according to any one of claims 1 to 8, characterized in that: The detection limit of the boron element is ≤1 ppb, and the relative standard deviation RSD of the detection result is ≤10%.

10. The detection method according to any one of claims 1 to 8, characterized in that: The method also includes daily calibration and maintenance of the detection instrument.

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