Method for determining zirconium content in high-purity volatile organic matrix environment by ICP-MS

Abstract

The application provides a method for determining the content of Zr metal ions in a high-purity volatile organic matrix environment by ICP-MS, comprising the following steps: (1) based on the volatile nature of the organic matrix, replacing the sampling system and debugging the instrument parameters; (2) acidifying the volatile organic matrix to be tested; (3) testing on the machine; (4) according to the generated standard curve, reading out the content of the metal ion Zr in the high-purity reagent IPA. The method directly and effectively improves the problem that the direct sampling ICP-MS cannot pull out the Zr element standard curve and thus cannot read out the content of Zr in IPA; meanwhile, the pretreatment method of the method is an acidification method, which is simple to operate and low in time cost; and the standard addition method can eliminate the matrix interference, realize the detection of the metal ion Zr under the high-purity matrix, and meet the production demand.

Description

Technical Field

[0001] This invention belongs to the field of high-purity organic reagent detection, and relates to the detection of Zr metal ion content in high-purity organic matrix environments. In particular, it relates to an improved pretreatment method to achieve the detection of Zr content in the semiconductor cleaning agent isopropanol by ICP-MS. Background Technology

[0002] Ultra-clean, high-purity reagents are among the key basic chemical materials in the fabrication of very large-scale integrated circuits (VLSI). They are primarily used for cleaning and etching chips, and their purity and cleanliness have a significant impact on the yield, electrical performance, and reliability of integrated circuits. High-purity isopropyl alcohol (IPA), as a cleaning agent, can effectively dissolve and remove contaminants such as metal ions, organic matter, and particulate matter from the chip surface. Furthermore, due to its volatility, IPA evaporates rapidly after cleaning, leaving no residue on the wafer surface, thus playing a crucial role in the chip manufacturing process.

[0003] With the continuous development of semiconductor micro-contamination cleaning and detection technologies, the requirements for the content of metallic and non-metallic impurities are becoming increasingly stringent. Currently, the commonly used analytical method for trace elements is inductively coupled plasma mass spectrometry (ICP-MS), which can achieve the detection of metallic and non-metallic impurities at the ppt level. The detection of trace metal impurity ions in high-purity reagents generally employs the standard addition method, meaning that the standard and sample are tested in the same matrix environment, achieving complete matrix matching and effectively avoiding matrix effects. However, this method is more suitable for samples with low content and high matrix properties. When Agilent 7900 detects Zr ions in high-purity organic reagent IPA, conventional dilution or direct injection of these two elements fails to produce linearity, thus making the detection impossible and challenging. Therefore, this invention addresses the shortcomings of Agilent 7900 in detecting high-purity organic reagent IPA by introducing a new pretreatment method to achieve ultra-trace Zr detection in a high-purity organic matrix environment with isopropanol or similar properties. Summary of the Invention

[0004] The present invention aims to provide a method for determining the content of Zr metal ions in a high-purity volatile organic matrix environment by ICP-MS, comprising the following steps: (1) based on the volatile nature of the organic matrix, changing the injection system and adjusting the instrument parameters; (2) acidifying the volatile organic matrix to be tested; (3) testing on the instrument; (4) reading back the content of Zr metal ions in the high-purity reagent IPA according to the generated standard curve.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] The method for determining the Zr metal ion content in a high-purity volatile organic matrix environment by ICP-MS provided by this invention includes the following steps:

[0007] (1) Instrument debugging

[0008] Based on the volatility of high-purity volatile organic matrices, the quartz rectangular tube of the organic sample introduction system was replaced, and the temperature of the nebulization chamber was adjusted to a temperature at which the volatile organic matrix does not volatilize. At the same time, an argon-oxygen mixed gas was introduced into the instrument to prevent the accumulation of carbon at the cone and to prevent instrument instability, signal drift, or instrument shutdown.

[0009] (2) Acidification of the organic matrix to be tested

[0010] Add the organic matrix to be tested to a clean PFA bottle, add 69% nitric acid to acidify the organic matrix to an acidity of 1.0% by mass, and the organic matrix is ​​diluted by approximately 1.01 times.

[0011] In this invention, the selected nitric acid is of grade G6, with each metal ion content ≤10ng / L, which does not affect the test results; the specific mass of nitric acid is calculated according to the following formula: nitric acid mass fraction = 69% nitric acid mass × 69% / total fixed volume mass.

[0012] (3) On-machine test

[0013] Ignite and preheat the instrument for 30 minutes. After preheating, perform hardware tuning, followed by custom tuning. Select Zr with a mass number of 90 in NoGas and He collision modes, and add Zr standard solution sequentially to the acidified organic matrix according to the set spiking concentration. After spiking, a standard curve will be displayed. If the standard curve is linear ≥ 0.9995, it indicates successful spiking. At this time, the Zr content in the IPA diluted 1.01 times can be directly read from the data table. The actual Zr content in the organic matrix needs to be multiplied by 1.01 from the instrument reading.

[0014] Preferably, the No Gas mode plasma power is 1600W, the sampling depth is 8mm, the nebulizer gas flow rate is 0.7L / min, and the compensation gas flow rate is 0.42L / min; the He collision mode plasma power is 1600W, the sampling depth is 8mm, the nebulizer gas flow rate is 0.7L / min, the compensation gas flow rate is 0.40L / min, and the helium flow rate is 2.2mL / min.

[0015] The correction method is the standard addition method, and the origin of the linear fitting curve is blank compensation.

[0016] In a preferred embodiment of the present invention, high-purity isopropanol is used as the organic matrix to test the content of Zr metal ions. The specific test method is as follows:

[0017] (1) Instrument debugging

[0018] The selected quartz rectangular tube has an inner diameter of 1.5 mm, and the atomization chamber temperature is -5℃ to prevent the volatilization of isopropanol. To prevent carbon buildup at the cone tip, a 10%–15% argon-oxygen mixture is required, containing 20% ​​oxygen, to prevent instrument instability, signal drift, or instrument shutdown.

[0019] (2) Acidification of the isopropanol to be tested

[0020] Add 99.9% IPA to a clean PFA bottle, the exact mass determined by weighing on a balance; add approximately 0.7246g of 69% nitric acid to acidify the IPA to a mass fraction of 1.0%, diluting the IPA by approximately 1.01 times. The exact mass of nitric acid can be calculated using the following formula: Nitric acid mass fraction = 69% nitric acid mass × 69% / total adjusted volume mass.

[0021] (3) On-machine test

[0022] Ignite and preheat the instrument for 30 minutes. After preheating, perform hardware tuning, followed by custom tuning. Then, create a new method and select Zr with a mass number of 90 in No Gas and He collision modes. The isopropanol detected in this invention is of UL grade from Jianghua Microelectronics Co., Ltd., with each metal ion content ≤1ug / L. Therefore, the spiking points of this invention are set to 50, 100, 200, 500, and 1000 ng / L based on this value. Add Zr standard solution to the acidified IPA sequentially according to the set spiking point concentrations. The specific spiking concentration points can be changed according to the actual spiking amount.

[0023] After spiking, a standard curve will be displayed. If the standard curve is linear (≥0.9995), it indicates that spiking was successful. At this time, the Zr content in the IPA diluted 1.01 times can be read directly from the data table. The actual Zr content in the IPA needs to be multiplied by 1.01 using the instrument reading.

[0024] By comparing the linearity of Zr in IPA obtained by direct injection and nitric acid acidification, it can be concluded that the linearity of nitric acid acidified IPA is good, which effectively improves the problem that direct injection IPA cannot produce a standard curve and thus cannot read back the Zr content in IPA. This is of great significance in actual operation.

[0025] This invention uses high-purity isopropanol as an example to determine the Zr content in a high-purity, volatile organic matrix environment using ICP-MS. The method of this invention is not limited to high-purity isopropanol; methods for detecting Zr content in other high-purity reagents with similar properties are also within the scope of this invention.

[0026] The beneficial effects of this invention are as follows:

[0027] This invention utilizes G6-grade 69% HNO3 acidification of high-purity IPA, effectively improving the linearity of the Zr standard curve. Furthermore, the standard addition method eliminates matrix interference, allowing direct determination of Zr content in high-purity isopropanol. This method directly and effectively addresses the problem that direct injection ICP-MS cannot produce a Zr elemental standard curve, thus preventing the re-reading of Zr content in IPA. In practical operation, the background value of Zr ions in G6-grade nitrate is ≤10 ng / L, which does not affect the test results. The pretreatment method, acidification, is simple to operate and has low time costs. The standard addition method eliminates matrix interference, enabling the detection of Zr ions in a high-purity matrix, meeting production requirements. Attached Figure Description

[0028] Figure 1 The present invention demonstrates the method and procedure for determining the Zr content in a high-purity volatile organic matrix environment using ICP-MS.

[0029] Figure 2 The standard curve for direct injection in No Gas mode is shown.

[0030] Figure 3 The standard curve for direct injection in He gas collision mode is shown.

[0031] Figure 4 The standard curve of nitric acid acidification under No Gas mode is shown.

[0032] Figure 5 The standard curve of nitric acid acidification under He collision mode is shown. Detailed Implementation

[0033] The present invention will be described in detail below with reference to the embodiments, but the present invention is not limited to the following embodiments.

[0034] All reagents and raw materials used in this invention are commercially available or can be prepared according to literature methods. Experimental methods in the following examples, unless otherwise specified, are generally performed under standard conditions or as recommended by the manufacturer.

[0035] I. Materials

[0036] Isopropanol is UL grade from Jianghua Microelectronics Co., Ltd., with each metal ion content ≤1ug / L; nitric acid is G6 grade, with each metal ion content ≤10ng / L, which does not affect the test results.

[0037] II. Experimental Methods

[0038] The procedure for determining the Zr metal ion content in high-purity isopropanol by ICP-MS is as follows: Figure 1 This includes the following steps:

[0039] (1) Change the sample injection system and adjust the instrument parameters.

[0040] Because isopropanol is highly volatile, a smaller diameter quartz rectangular tube for the organic sample introduction system is required. At the same time, the temperature of the nebulization chamber should be adjusted to -5°C to prevent the volatilization of isopropanol. To prevent carbon buildup at the cone, a 10%–15% argon-oxygen mixture containing 20% ​​oxygen should be introduced to prevent instrument instability, signal drift, or instrument shutdown.

[0041] (2) Acidification of the isopropanol to be tested

[0042] Add 49.2754g of IPA (99.9%) to a clean PFA bottle; the exact mass should be determined by weighing on a balance. Add approximately 0.7246g of 69% nitric acid to acidify the IPA to a mass fraction of 1.0%. The final volumetric mass is 50.0000g, and the IPA is diluted approximately 1.01 times. The exact mass of nitric acid can be calculated using the following formula: Nitric acid mass fraction = 69% nitric acid mass × 69% / total volumetric mass.

[0043] (3) On-machine test

[0044] Ignite and preheat the instrument for 30 minutes. After preheating, perform hardware tuning, followed by custom tuning. Then, create a new method and select Zr with a mass number of 90 in No Gas and He collision modes. The spiking points set in this invention are 50, 100, 200, 500, and 1000 ng / L. Add Zr standard solution to the acidified IPA sequentially according to the set spiking point concentrations. The specific spiking concentration points can be changed according to the actual spiking amount.

[0045] The No Gas mode plasma power was 1600W, the sampling depth was 8mm, the nebulizer gas flow rate was 0.7L / min, and the compensation gas flow rate was 0.42L / min; the He collision mode plasma power was 1600W, the sampling depth was 8mm, the nebulizer gas flow rate was 0.7L / min, the compensation gas flow rate was 0.40L / min, and the helium flow rate was 2.2mL / min.

[0046] After spiking, a standard curve will be displayed. If the standard curve is linear (≥0.9995), it indicates that spiking was successful. At this time, the Zr content in the IPA diluted 1.01 times can be read directly from the data table. The actual Zr content in the IPA needs to be multiplied by 1.01 using the instrument reading.

[0047] Before and after improvement and optimization, the effect is as follows: Figures 2-5 As shown: Figures 2-3 The standard curve for direct injection is shown. Under this injection mode, the linearity of the standard curve is <0.9995, which does not meet the test requirements. Figure 4 and Figure 5The standard curves for the injection after acidification are shown. The linearity is good in both the No Gas and He collision modes, both ≥0.9995, which meets the test requirements.

[0048] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A method for determining the Zr metal ion content in a high-purity volatile organic matrix environment by ICP-MS, characterized in that, Includes the following steps: (1) Instrument debugging Based on the volatility of high-purity volatile organic matrix, the quartz rectangular tube of the organic sample introduction system is replaced, and the temperature of the nebulization chamber is adjusted to a temperature at which the volatile organic matrix does not volatilize; at the same time, an argon-oxygen mixed gas is introduced into the instrument to prevent the accumulation of carbon at the cone and to prevent instrument instability, signal drift, or instrument shutdown; wherein, the high-purity volatile organic matrix is ​​selected from high-purity isopropanol. (2) Acidification of the organic matrix to be tested Add the organic matrix to be tested to a clean PFA bottle, add 69% nitric acid to acidify the organic matrix to an acidity of 1.0% by mass, and the organic matrix is ​​diluted to 1.01 times. (3) On-machine testing After igniting and preheating the instrument, tune it. Select Zr with a mass number of 90 in No Gas and He collision modes, and add Zr standard solution sequentially to the acidified organic matrix to be tested according to the set spiking concentration. After spiking, a standard curve will be displayed. If the standard curve is linear ≥ 0.9995, it indicates that the spiking was successful. At this time, the Zr content in the IPA diluted 1.01 times can be directly read from the data table. The actual Zr content in the organic matrix to be tested needs to be multiplied by 1.01 by the instrument reading.

2. The method for determining the Zr metal ion content in a high-purity volatile organic matrix environment by ICP-MS according to claim 1, characterized in that, In step (1), the inner diameter of the quartz rectangular tube is 1.5 mm and the temperature of the atomization chamber is –5°C.

3. The method for determining the Zr metal ion content in a high-purity volatile organic matrix environment by ICP-MS according to claim 1, characterized in that, In step (1), the volume fraction of the argon-oxygen mixture introduced is 10% to 15%, and the mixture contains 20% oxygen.

4. The method for determining the Zr metal ion content in a high-purity volatile organic matrix environment by ICP-MS according to claim 1, characterized in that, In step (2), the nitric acid is grade G6, and the content of each metal ion is ≤10ng / L; the specific mass of nitric acid is calculated according to the following formula: nitric acid mass fraction = 69% nitric acid mass × 69% / total fixed volume mass.

5. The method for determining the Zr metal ion content in a high-purity volatile organic matrix environment by ICP-MS according to claim 1, characterized in that, In step (3), the instrument is ignited and preheated for 30 minutes. After preheating, hardware tuning is performed, followed by custom tuning.

6. The method for determining the Zr metal ion content in a high-purity volatile organic matrix environment by ICP-MS according to claim 1, characterized in that, In step (3), the spiking concentrations are set to 50, 100, 200, 500, and 1000 ng / L. The specific spiking concentration can be changed according to the actual amount of spiking.

7. The method for determining the Zr metal ion content in a high-purity volatile organic matrix environment by ICP-MS according to claim 1, characterized in that, In step (3), the plasma power in No Gas mode is 1600W, the sampling depth is 8mm, the atomizing gas flow rate is 0.7L / min, and the compensation gas flow rate is 0.42L / min; The plasma power for the He gas collision mode was 1600W, the sampling depth was 8mm, the atomizing gas flow rate was 0.7L / min, the compensation gas flow rate was 0.40L / min, and the helium flow rate was 2.2mL / min.

8. The method for determining the Zr metal ion content in a high-purity volatile organic matrix environment by ICP-MS according to claim 1, characterized in that, In step (3), the correction method is the standard addition method, and the origin of the linear fitting curve is blank compensation.

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