A sample solution preparation method for trace impurity analysis of high-purity trimethylaluminum

Abstract

The application discloses a sample solution preparation method for trace impurity analysis of high-purity trimethylaluminum, and belongs to the technical field of trace impurity analysis, and the preparation steps are as follows: a magnetic stirring rotor is placed in a flue gas absorption bottle, nitric acid solution is added, and a magnetic stirring heater is started; high-purity trimethylaluminum is added into an oxidation decomposition bottle, a gas cylinder pressure reducing valve and an air inlet valve are opened, oxygen-nitrogen mixed gas in a gas cylinder is transported into the oxidation decomposition bottle, then an air outlet valve and an automatic one-way valve are opened, when there is no high-purity trimethylaluminum in the oxidation decomposition bottle, all the valves are closed, and a sample solution for trace impurity analysis of high-purity trimethylaluminum is obtained. The application adopts the method of oxidizing and decomposing trimethylaluminum by using high-purity oxygen-nitrogen mixed gas, and then nitric acid solution is used to dissolve aluminum oxide powder to prepare an aluminum ion nitric acid solution. The application has the advantages of single chemical variety, low concentration, no need for additional treatment of tail gas, simpler device structure, easy operation, low investment cost, safety, economy, and environmental protection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of trace impurity analysis, and particularly relates to a sample solution preparation method for trace impurity analysis of high-purity trimethylaluminum. BACKGROUND

[0002] High-purity trimethylaluminum is a commonly used deposition aluminum source in the manufacture of integrated circuit chips, photovoltaic perc battery pieces and LED chips in the semiconductor industry, and is a dangerous chemical with very active properties, which can spontaneously burn in the air and explode when encountering water. Therefore, trimethylaluminum cannot be directly sampled and detected in an inductively coupled plasma mass spectrometer (ICP-MS), and must be prepared into an acidic solution of aluminum ions through a specific method to perform trace impurity analysis.

[0003] Chinese Patent CN102103049B discloses a trimethylaluminum HCl decomposition device for trace impurity analysis of trimethylaluminum, and a device structure schematic diagram is shown in Figure 2 The device uses concentrated sulfuric acid and concentrated hydrochloric acid to prepare HCl gas, and reacts the HCl gas with trimethylaluminum to obtain water-soluble AlCl3 powder. The decomposition device needs to use concentrated sulfuric acid and concentrated hydrochloric acid, which are highly dangerous due to high concentration; and the rate, amount and pressure of the prepared HCl gas are difficult to control, and if the pipeline is not tightly sealed or is improperly operated, a small amount of HCl gas may escape to harm the health of the operator; at the same time, the excess HCl methane tail gas must be treated by NaOH solution absorption before being discharged; the trimethylaluminum sample bottle in the decomposition device must be placed in a sealed glove box, and the total investment cost of the device is high; the trimethylaluminum HCl decomposition device has a complex structure, uses more dangerous chemicals with high concentration, and the operation is also relatively complex, and improper operation may harm the health of the operator.

[0004] Therefore, it is necessary to provide a sample solution for trace impurity analysis of high-purity trimethylaluminum, which is simpler and safer. SUMMARY

[0005] The purpose of the application is to solve the sample solution preparation method for ICP-MS technical analysis of trace impurities in high-purity trimethylaluminum used for deposition of integrated circuit chips, solar cell pieces and LED chips, which oxidizes and decomposes trimethylaluminum by using high-purity oxygen-nitrogen mixed gas, then dissolves the aluminum oxide powder with nitric acid solution to prepare an aluminum ion nitric acid solution, uses single type of chemical with low concentration, does not need additional treatment of tail gas, has a simpler device structure and is easy to operate, has low investment cost, is safe, economical and environmentally friendly.

[0006] The purpose of the application can be achieved by the following technical solutions:

[0007] A sample solution preparation method for trace impurity analysis of high-purity trimethylaluminum, comprising the following steps:

[0008] In the first step, a magnetic stirring rotor is placed in the flue gas absorption bottle of the oxidative decomposition device, and nitric acid solution is added. The magnetic stirring heater is turned on, the rotating speed is controlled at 500-1000 r / min, and the temperature is controlled at 40-98℃.

[0009] In the second step, high-purity trimethylaluminum is added to the oxidative decomposition bottle. The gas cylinder pressure reducing valve and the gas inlet valve are opened. The rotor flowmeter valve is opened and the flow is adjusted so that the oxygen-nitrogen mixed gas flow rate is 5 mL / min-2 L / min. The oxygen-nitrogen mixed gas cylinder gas is transported to the oxidative decomposition bottle, so that the oxygen reacts with the trimethylaluminum to form nano-sized aluminum oxide particles. Then the gas outlet valve and the automatic one-way valve are opened, so that the generated nano-sized aluminum oxide particles are carried into the flue gas absorption bottle by the gas flow and react with the nitric acid solution. When there is no high-purity trimethylaluminum in the oxidative decomposition bottle, all the valves of the oxidative decomposition device are closed, and a sample solution for trace impurity analysis of high-purity trimethylaluminum is obtained.

[0010] Further, the oxidative decomposition device comprises an oxygen-nitrogen mixed gas cylinder, an oxidative decomposition bottle and a flue gas absorption bottle. The oxygen-nitrogen mixed gas cylinder is provided with a gas cylinder pressure reducing valve at the upper end. The gas cylinder pressure reducing valve is connected with a gas inlet pipe at the end away from the oxygen-nitrogen mixed gas cylinder. The end of the gas inlet pipe away from the oxygen-nitrogen mixed gas cylinder is located inside the oxidative decomposition bottle. A rotor flowmeter and a gas inlet valve are installed on the gas inlet pipe. By controlling the gas cylinder pressure reducing valve and the gas inlet valve, the oxygen-nitrogen mixed gas cylinder gas is transported to the oxidative decomposition bottle. The rotor flowmeter is used to monitor the gas flow rate in the gas inlet pipe, so as to adjust the gas flow rate.

[0011] The oxidative decomposition bottle is further provided with an exhaust pipe. The exhaust pipe is provided with a gas outlet valve and an automatic one-way valve. By controlling the gas outlet valve and the automatic one-way valve, the gas in the oxidative decomposition bottle is exhausted. The end of the exhaust pipe away from the oxidative decomposition bottle is communicated with the inner extension pipe of the end porous structure. The inner extension pipe of the end porous structure is located inside the flue gas absorption bottle.

[0012] Further, the rotor flowmeter is located at the end close to the oxygen-nitrogen mixed gas cylinder, and the gas inlet valve is located at the end close to the oxidative decomposition bottle.

[0013] Further, the flue gas absorption bottle is provided with a magnetic stirring heater at the bottom end.

[0014] Further, the oxidative decomposition bottle, the flue gas absorption bottle, the inner extension pipe of the end porous structure, the gas inlet pipe and the exhaust pipe are all made of polytetrafluoroethylene.

[0015] Further, the bottom end of the inner extension pipe of the end porous structure is a porous structure and is located in the flue gas absorption bottle, 20 mm away from the bottom of the flue gas absorption bottle, and the pore size is 0.2-0.5 mm.

[0016] The bottom of the flue gas absorption bottle has a magnetic rotor for high-speed stirring of the absorption liquid, which can disperse and break the flue gas bubbles and increase the contact area and time of the aluminum oxide and the nitric acid solution; at the same time, the flue gas absorption bottle is heated by the magnetic stirring heater, so that the temperature of the nitric acid solution is always maintained at 40-98℃, and the reaction rate of the nitric acid solution nitrating the aluminum oxide flue gas is increased.

[0017] Further, the concentration of the nitric acid solution in the flue gas absorption bottle is 5%-30%, and the liquid level is 6-15cm.

[0018] Further, the volume ratio of the nitric acid solution and the high-purity trimethylaluminum is 6-36:1.

[0019] Further, the gas content ratio in the oxygen-nitrogen mixed gas bottle is: oxygen 0.1%-50%, nitrogen 50%-99.9%, and both are high-purity gases with a purity of 5N or more.

[0020] Further, the upper end of the oxidation decomposition bottle is provided with a sealing cover, and the oxidation decomposition bottle is sealingly connected with the gas inlet pipe and the gas outlet pipe.

[0021] The beneficial effects of the present application are:

[0022] 1. The sample solution for trace impurity analysis of high-purity trimethylaluminum prepared by the present application, wherein the aluminum content is determined by EDTA complexometric titration method, and the aluminum ion loss rate of the sample solution prepared by the method is not more than 2% after calculation.

[0023] 2. The present application uses high-purity oxygen-nitrogen mixed gas to oxidize and decompose trimethylaluminum, and then uses nitric acid solution to dissolve aluminum oxide powder to prepare aluminum ion nitric acid solution. The types of chemicals used are single and low in concentration, the tail gas does not need additional treatment, the device structure is simpler and easier to operate, the investment cost is low, and it is safe, economical and environmentally friendly.

[0024] 3. The bottom of the flue gas absorption bottle has a magnetic rotor for high-speed stirring of the absorption liquid, which can disperse and break the flue gas bubbles and increase the contact area and time of the aluminum oxide and the nitric acid solution; at the same time, the flue gas absorption bottle is heated by the magnetic stirring heater, so that the temperature of the nitric acid solution is always maintained at 40-98℃, and the reaction rate of the nitric acid solution nitrating the aluminum oxide flue gas is increased. BRIEF DESCRIPTION OF DRAWINGS

[0025] The present application will be further described below with reference to the accompanying drawings.

[0026] Figure 1 is a structural schematic view of the oxidation decomposition device of the present application;

[0027] Figure 2 is a structural schematic view of the trimethylaluminum HCl decomposition device for trace impurity analysis of trimethylaluminum in the background art;

[0028] Figure: 1, oxygen-nitrogen mixed gas cylinder; 2, cylinder pressure reducing valve; 3, rotor flow meter; 4, gas inlet valve; 5, oxidation decomposition bottle; 6, gas outlet valve; 7, automatic one-way valve; 8, flue gas absorption bottle; 9, inner extension pipe with porous structure at the end; 10, magnetic stirring heater. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0030] Embodiment 1

[0031] Please refer to Figure 1 A sample solution preparation method for trace impurity analysis of high-purity trimethylaluminum includes the following steps:

[0032] Step 1: Place a magnetic stirring rotor in the flue gas absorption bottle 8 of the oxidation decomposition device, and add 60 mL of 10% nitric acid solution with a liquid level of 6 cm. Turn on the magnetic stirring heater 10, control the rotating speed to be 500 r / min, and control the temperature to be 45℃.

[0033] Step 2: Add 10 mL of high-purity trimethylaluminum to the oxidation decomposition bottle 5. Turn on the cylinder pressure reducing valve 2 and the gas inlet valve 4. Open the valve of the rotor flow meter 3 and adjust the flow rate so that the flow rate of the oxygen-nitrogen mixed gas is 10 mL / min. Transport the gas in the oxygen-nitrogen mixed gas cylinder 1 to the oxidation decomposition bottle 5 so that the oxygen reacts with the trimethylaluminum to form nanoscale aluminum oxide particles. Then open the gas outlet valve 6 and the automatic one-way valve 7 so that the generated nanoscale aluminum oxide particles are carried into the flue gas absorption bottle 8 by the gas flow and react with the nitric acid solution. When there is no high-purity trimethylaluminum in the oxidation decomposition bottle 5, close all the valves of the oxidation decomposition device to obtain a sample solution for trace impurity analysis of high-purity trimethylaluminum.

[0034] The oxidation decomposition device includes the oxygen-nitrogen mixed gas cylinder 1, the oxidation decomposition bottle 5, and the flue gas absorption bottle 8. The cylinder pressure reducing valve 2 is installed at the upper end of the oxygen-nitrogen mixed gas cylinder 1. The cylinder pressure reducing valve 2 is connected with a gas inlet pipe at the end far from the oxygen-nitrogen mixed gas cylinder 1. The end of the gas inlet pipe far from the oxygen-nitrogen mixed gas cylinder 1 is located inside the oxidation decomposition bottle 5. The rotor flow meter 3 and the gas inlet valve 4 are installed on the gas inlet pipe. By controlling the cylinder pressure reducing valve 2 and the gas inlet valve 4, the gas in the oxygen-nitrogen mixed gas cylinder 1 is transported to the oxidation decomposition bottle 5. The rotor flow meter 3 monitors the flow rate of the gas in the gas inlet pipe, which facilitates the adjustment of the flow rate of the gas.

[0035] The inside of the oxidative decomposition bottle 5 is further provided with an exhaust pipe, on which an air outlet valve 6 and an automatic one-way valve 7 are installed. By controlling the air outlet valve 6 and the automatic one-way valve 7, the gas inside the oxidative decomposition bottle 5 is exhausted. The end of the exhaust pipe away from the oxidative decomposition bottle 5 is in communication with the inner extension pipe 9 of the terminal porous structure, which is located inside the flue gas absorption bottle 8. The bottom end of the flue gas absorption bottle 8 is provided with a magnetic stirring heater 10.

[0036] The upper end of the oxidative decomposition bottle 5 is provided with a sealing cover, and the oxidative decomposition bottle 5 is sealingly connected with the air inlet pipe and the exhaust pipe.

[0037] The rotor flowmeter 3 is located at one end close to the oxygen-nitrogen mixed gas bottle 1, and the air inlet valve 4 is located at one end close to the oxidative decomposition bottle 5.

[0038] The oxidative decomposition bottle 5, the flue gas absorption bottle 8, the inner extension pipe 9 of the terminal porous structure, the air inlet pipe and the exhaust pipe are all made of polytetrafluoroethylene.

[0039] The bottom end of the inner extension pipe 9 of the terminal porous structure is a porous structure and is located in the flue gas absorption bottle 8, 20 mm away from the bottom of the flue gas absorption bottle 8, with a pore size of 0.2-0.5 mm.

[0040] The gas content ratio in the oxygen-nitrogen mixed gas bottle 1 is: oxygen 50%, nitrogen 50%, both of which are high-purity gases with a purity of 5N or above.

[0041] The sample solution obtained in Example 1 was detected, and the aluminum content was determined by EDTA complexometric titration method. It is calculated that the aluminum ion loss rate of the sample solution prepared by this method is 1.2%.

[0042] Example 2

[0043] A sample solution preparation method for high-purity trimethylaluminum trace impurity analysis includes the following steps:

[0044] First step, place the magnetic stirring rotor in the flue gas absorption bottle 8 of the oxidative decomposition device, and add 360 mL of 30% concentrated nitric acid solution with a liquid level of 15 cm. Turn on the magnetic stirring heater 10, control the rotating speed to 1000 r / min, and the temperature to 95℃.

[0045] The second step is to add 10 mL of high-purity trimethylaluminum into the oxidation decomposition bottle 5, open the gas cylinder pressure reducing valve 2 and the gas inlet valve 4, open the valve of the rotor flowmeter 3 and adjust the flow rate so that the oxygen-nitrogen mixed gas flow rate is 1 L / min, transport the oxygen-nitrogen mixed gas cylinder 1 to the oxidation decomposition bottle 5, make the oxygen react with the trimethylaluminum to form nano-sized aluminum oxide particles, then open the gas outlet valve 6 and the automatic one-way valve 7, and make the generated nano-sized aluminum oxide particles be carried into the flue gas absorption bottle 8 by the gas flow and react with the nitric acid solution, when there is no high-purity trimethylaluminum in the oxidation decomposition bottle 5, close all the valves of the oxidation decomposition device, and obtain a sample solution for analyzing the trace impurities of high-purity trimethylaluminum.

[0046] The oxidation decomposition device comprises the oxygen-nitrogen mixed gas cylinder 1, the oxidation decomposition bottle 5 and the flue gas absorption bottle 8, the oxygen-nitrogen mixed gas cylinder 1 is provided with the gas cylinder pressure reducing valve 2 at the upper end, the gas cylinder pressure reducing valve 2 is connected with the gas inlet pipe at the end far from the oxygen-nitrogen mixed gas cylinder 1, and the end of the gas inlet pipe far from the oxygen-nitrogen mixed gas cylinder 1 is located inside the oxidation decomposition bottle 5; the gas inlet pipe is provided with the rotor flowmeter 3 and the gas inlet valve 4, the oxygen-nitrogen mixed gas cylinder 1 is transported to the oxidation decomposition bottle 5 by controlling the gas cylinder pressure reducing valve 2 and the gas inlet valve 4, and the rotor flowmeter 3 is used to monitor the gas flow rate in the gas inlet pipe, so as to adjust the gas flow rate.

[0047] The oxidation decomposition bottle 5 is further provided with the exhaust pipe, the exhaust pipe is provided with the gas outlet valve 6 and the automatic one-way valve 7, the gas in the oxidation decomposition bottle 5 is exhausted by controlling the gas outlet valve 6 and the automatic one-way valve 7, the end of the exhaust pipe far from the oxidation decomposition bottle 5 is communicated with the inner extension pipe 9 with the porous structure at the end, the inner extension pipe 9 with the porous structure at the end is located inside the flue gas absorption bottle 8, and the flue gas absorption bottle 8 is provided with the magnetic stirring heater 10 at the bottom end.

[0048] The oxidation decomposition bottle 5 is provided with the sealing cover at the upper end, and the oxidation decomposition bottle 5 is sealingly connected with the gas inlet pipe and the exhaust pipe

[0049] The rotor flowmeter 3 is located at the end close to the oxygen-nitrogen mixed gas cylinder 1, and the gas inlet valve 4 is located at the end close to the oxidation decomposition bottle 5.

[0050] The oxidation decomposition bottle 5, the flue gas absorption bottle 8, the inner extension pipe 9 with the porous structure at the end, the gas inlet pipe and the exhaust pipe are all made of polytetrafluoroethylene.

[0051] The bottom end of the inner extension pipe 9 with the porous structure at the end is the porous structure, is located in the flue gas absorption bottle 8, is 20 mm away from the bottle bottom of the flue gas absorption bottle 8, and has a pore size of 0.2-0.5 mm.

[0052] The gas content ratio in the oxygen-nitrogen mixed gas cylinder 1 is that the oxygen is 50%, the nitrogen is 50%, and both are high-purity gases with a purity of 5N or above.

[0053] The sample solution obtained from the high-purity trimethylaluminum of Example 2 was detected, and the aluminum content was determined by EDTA complexometric titration. It was calculated that the aluminum ion loss rate of the sample solution prepared by the method was 0.8%.

[0054] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another, without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0055] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, alternatives, and variations can be made in the embodiments without departing from the spirit and scope of the present application as defined by the appended claims and their equivalents.

Claims

1. A method for preparing a sample solution for trace impurity analysis of high-purity trimethylaluminum, characterized in that: The steps include: The first step is to place a magnetic stirring rotor in the flue gas absorption bottle (8) of the oxidation decomposition device, add nitric acid solution, turn on the magnetic stirring heater (10), control the speed to 500-1000 r / min, and the temperature to 40-98°C; The second step is to add high-purity trimethylaluminum to the oxidation decomposition bottle (5), open the gas cylinder pressure reducing valve (2) and the air inlet valve (4), open the rotor flowmeter (3), and transport the gas from the oxygen-nitrogen mixed gas cylinder (1) to the oxidation decomposition bottle (5), so that oxygen reacts with trimethylaluminum to form nano-scale aluminum oxide particles. Then, the gas outlet valve (6) and the automatic one-way valve (7) are opened, so that the generated nano-scale aluminum oxide particles are carried by the air flow into the flue gas absorption bottle (8) to react with the nitric acid solution. When there is no high-purity trimethylaluminum in the oxidation decomposition bottle (5), all valves of the oxidation decomposition device are closed to obtain a sample solution for trace impurity analysis of high-purity trimethylaluminum. The oxidation decomposition device comprises an oxygen-nitrogen mixed gas cylinder (1), an oxidation decomposition cylinder (5) and a flue gas absorption cylinder (8); a cylinder pressure reducing valve (2) is installed at the upper end of the oxygen-nitrogen mixed gas cylinder (1); one end of the cylinder pressure reducing valve (2) is connected to an air inlet pipe, and one end of the air inlet pipe is located inside the oxidation decomposition cylinder (5); The intake pipe is equipped with a rotor flowmeter (3) and an intake valve (4); An exhaust pipe is further provided inside the oxidation decomposition bottle (5), and an exhaust valve (6) and an automatic one-way valve (7) are installed on the exhaust pipe. One end of the exhaust pipe is connected to an inner extension pipe (9) with a porous structure at the end, and the inner extension pipe (9) with a porous structure at the end is located inside the flue gas absorption bottle (8); A magnetic stirring heater (10) is installed at the bottom of the flue gas absorption bottle (8); The concentration of nitric acid solution is 5%-30%; The gas content ratio in the oxygen-nitrogen mixed gas cylinder (1) is: oxygen 0.1%-50%, nitrogen 50%-99.9%, both of which are high-purity gases with a purity of more than 5N.

2. The method for preparing a sample solution for trace impurity analysis of high-purity trimethylaluminum according to claim 1, characterized in that: The oxidation decomposition bottle (5), the fume absorption bottle (8), the inner extension tube (9) with a porous structure at the end, the air inlet pipe and the exhaust pipe are all made of polytetrafluoroethylene.

3. The method for preparing a sample solution for trace impurity analysis of high-purity trimethylaluminum according to claim 1, characterized in that: The bottom end of the inner extension tube (9) with a porous structure at the end is a porous structure and is located in the smoke absorption bottle (8), 20 mm away from the bottom of the smoke absorption bottle (8), with a pore diameter of 0.2-0.5 mm.

4. The method for preparing a sample solution for trace impurity analysis of high-purity trimethylaluminum according to claim 1, characterized in that: The volume ratio of the nitric acid solution to high-purity trimethylaluminum is 6-36:1.

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