Purification device and purification method for semiconductor-grade ultra-high-purity deuterium gas

Abstract

The invention relates to the technical field of deep purification of deuterium gas, in particular to a purification device and a purification method of semiconductor-grade ultra-high-purity deuterium gas. The crude deuterium gas is introduced into a storage tank and then enters a deep deoxidization tower for deep deoxidization, the discharged gas is preheated and then enters a deep impurity removal tower for deep impurity removal, and finally the ultra-high-purity deuterium gas is obtained. According to the purification method, the deuterium gas crude product with the purity reaching 99.8% or above can be deeply purified, the purity of the obtained deuterium gas is larger than or equal to 99.9998%, and the requirement for ultra-high-purity deuterium gas in the high-precision electronic field is met; according to the purification method, by-product heavy water generated in the deoxidation link is effectively recycled, the yield of the heavy water is increased, material waste is reduced, and the process method can have high production capacity while meeting the product purity requirement, and can meet large-scale industrial production.

Description

Technical Field

[0001] The present application belongs to the technical field of deep deuterium gas purification, and specifically relates to a semiconductor-grade ultra-high purity deuterium gas purification device and purification method. Background Art

[0002] Deuterium is a naturally occurring, stable isotope of hydrogen, also known as heavy hydrogen. Its symbol is D, and its content in nature is about one-seven thousandth of that of hydrogen.

[0003] In recent years, deuterium gas has been considered a strategic new product in the specialty gas industry, mainly used in high-voltage annealing equipment for integrated circuits to prevent leakage current caused by tunneling in processes of 28nm and below. In the semiconductor manufacturing process, there are very high requirements for the purity of deuterium gas, including the requirement that the N2 content be less than 0.01ppm, the THC content be less than 0.02ppm, and the CO content be less than 0.01ppm. In addition to the above, the content of other impurities must also be less than 0.01ppm.

[0004] Chinese invention patent CN 117383656A mentions a method and device for pre-treating heavy water with a degassing membrane to improve the electrolysis preparation of high-purity deuterium gas. The device includes an electrolytic cell, an oxygen separator, a deuterium separator, a drying tower, a degassing membrane assembly, etc. This method completes the primary purification of heavy water through the pretreatment of the degassing membrane assembly, removes impurities such as oxygen, nitrogen, and methane, and then makes the deuterium gas produced by electrolysis contain only a trace amount of water. This method requires sufficient treatment of the raw materials in the early stage. If the impurity content in the finished deuterium gas does not meet the requirements, the unqualified products cannot be effectively treated, and the purity of the finished deuterium gas does not meet the requirements of some semiconductor manufacturers for ultra-high purity deuterium gas.

[0005] Chinese invention patent CN 116571050A mentions a purification device for preparing high-purity deuterium gas by electrolyzing heavy water. The device has a good adsorption effect on the main impurities in deuterium gas, and the product purity is high, but it is only suitable for laboratories or small-scale commercial equipment, and cannot meet the needs of semiconductor customers with large demand.

[0006] Therefore, the purity of high-purity deuterium gas produced in the prior art still cannot meet the purity requirements of some semiconductor customers, and the purity of high-purity deuterium gas cannot be mass-produced. Summary of the invention

[0007] In view of the fact that the purity of high-purity deuterium gas produced in the prior art still cannot meet the purity requirements of some semiconductor customers, and the purity of high-purity deuterium gas cannot be mass-produced, the present application proposes a method for purifying semiconductor-grade ultra-high-purity deuterium gas, aiming to obtain ultra-high-purity deuterium gas that meets the requirements of semiconductor customers, and at the same time can achieve large-scale production of more than 10T per year. At the same time, there are corresponding processing links for unqualified products, as well as the recycling of heavy water, which reduces the loss of finished products and raw materials and improves the yield of deuterium gas.

[0008] The technical solution of this application is as follows:

[0009] On the one hand, the present application provides a semiconductor-grade ultra-high purity deuterium gas purification device, including a storage tank, a deoxidation tower, a heat exchanger and an adsorption tower;

[0010] The storage tank is provided with a crude deuterium gas inlet and a crude deuterium gas outlet, the deoxidation tower is provided with a deoxidation tower inlet and a deoxidation tower outlet, the heat exchanger is provided with a first inlet and a first outlet at both ends, the heat exchanger is provided with a second inlet and a second outlet at the side, and the adsorption tower is provided with an adsorption tower inlet at the bottom and an adsorption tower outlet at the top;

[0011] The crude deuterium gas outlet on the storage tank is connected to the deoxygenation tower inlet on the deoxygenation tower, the deoxygenation tower outlet on the deoxygenation tower is connected to the first inlet, the first outlet is connected to the adsorption tower inlet at the bottom of the adsorption tower, the adsorption tower outlet at the top of the adsorption tower is connected to the second inlet on the side of the heat exchanger, and the second outlet on the side of the heat exchanger is connected to the deuterium gas filling tank through a pipeline.

[0012] Preferably, a first detector is provided on the top of the storage tank; a liquid outlet is provided at the bottom of the deoxygenation tower, and the liquid outlet is connected to a liquid recovery tank; a second detector is provided on the pipeline connecting the heat exchanger and the deuterium gas filling tank, and both the first detector and the second detector are used to detect gas components, and both the first detector and the second detector are gas chromatographs.

[0013] On the other hand, the present application provides a method for purifying semiconductor-grade ultra-high purity deuterium gas, specifically: crude deuterium gas is passed into a storage tank, then enters a deoxidation tower for deoxidation, the gas coming out of the deoxidation tower is preheated, and then enters an adsorption tower for impurity removal, and finally ultra-high purity deuterium gas is obtained. .

[0014] Preferably, the purity of the crude deuterium gas is ≥99.8%.

[0015] Preferably, the temperature of the deep deoxygenation is 15-60°C.

[0016] Preferably, the temperature of the deep impurity removal is 350-650°C.

[0017] Preferably, the gas flow rate of the deep deoxygenation is 3-15 Nm 3 / h.

[0018] Preferably, the preheating temperature is 100-280°C.

[0019] The beneficial effects of this application are as follows:

[0020] (1) This purification method can deeply purify crude deuterium gas with a purity of more than 99.8%. Through the deep purification process, various impurities such as nitrogen, oxygen, carbon monoxide, carbon dioxide, hydrocarbons and water in the crude deuterium gas can be deeply removed. The purity of the deuterium gas is ≥99.9998%, which meets the requirements of the high-precision electronics field for ultra-high purity deuterium gas;

[0021] (2) This purification method can effectively recycle the byproduct heavy water generated in the deoxygenation step, thereby increasing the yield of heavy water, reducing material waste, and achieving effective utilization of resources;

[0022] (3) The process is simple, including three main steps: deep deoxygenation, deep impurity removal, and heavy water recovery. Each step has detailed and clear operating parameters and control requirements, making the purification process easy to operate and control. At the same time, the process is also highly flexible and can be adjusted and optimized according to the different components and purity requirements of the raw gas;

[0023] (4) This process method can meet the product purity requirements while having a large production capacity and can meet the needs of large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solution of the embodiments of the present application, the drawings of the embodiments are briefly introduced below.

[0025] The drawings described below only relate to some embodiments of the present application and are not intended to limit the present application.

[0026] In the attached picture:

[0027] Figure 1 This is a diagram of a semiconductor-grade ultra-high purity deuterium gas purification device of the present application.

[0028] Figure numerals: 1, storage tank; 2, deoxygenation tower; 3, heat exchanger; 4, adsorption tower; 5, crude deuterium gas inlet; 6, first detector; 7, crude deuterium gas outlet; 8, deoxygenation tower inlet; 9, deoxygenation tower outlet; 10, second outlet; 11, liquid recovery tank; 12, first inlet; 13, first outlet; 14, second inlet; 15, adsorption tower inlet; 16, adsorption tower outlet; 17, second detector; 18, deuterium gas filling tank. DETAILED DESCRIPTION

[0029] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the specific implementation method, structure, characteristics and effects of the present application are described in detail below in combination with the preferred embodiments.

[0030] Device Embodiment

[0031] This embodiment provides a semiconductor-grade ultra-high purity deuterium gas purification device, see the attached Figure 1 , including a storage tank 1, a deoxidation tower 2, a heat exchanger 3 and an adsorption tower 4;

[0032] Storage tank 1 is used to store crude deuterium gas or ordinary index deuterium gas. Storage tank 1 is provided with crude deuterium gas inlet and crude deuterium gas outlet 7, deoxidation tower 2. Deoxidation tower 2 in this embodiment uses cuprous oxide as a reducing agent and adopts 156 series palladium catalyst to remove impurities such as O2 and H2O in crude deuterium gas through reduction reaction, and at the same time reduce CO2 to CO which is more easily removed. Deoxidation tower 2 is provided with deoxidation tower inlet 8 and deoxidation tower outlet 9. Impurities such as N2, THC, H2, CO, etc. that are not removed in deoxidation tower 2 and raw gas deuterium gas enter heat exchanger 3 from deoxidation tower outlet 9. Heat exchanger 3 is used to deoxidize the deuterium gas coming from deoxidation tower 2. Preheating and cooling the deuterium gas coming out of the adsorption tower 4 to facilitate the filling of deuterium gas. The first inlet 12 and the first outlet 13 are respectively provided at both ends of the heat exchanger 3, and the second inlet 14 and the second outlet 10 are respectively provided on both sides of the heat exchanger 3; the adsorption tower 4, the adsorption tower 4 is provided with an adsorption tower inlet 15 at the bottom and an adsorption tower outlet 16 at the top. In this embodiment, the adsorption tower 4 uses palladium hydrogen storage material as the adsorption material. The adsorption material has the characteristics of adsorbing and releasing deuterium gas at high temperature, and is used to remove other impurities including N2, CO, and THC in the deuterium gas. The purified deuterium gas enters the final secondary analysis and filling link. ;

[0033] The crude deuterium gas outlet 7 on the storage tank 1 is connected to the deoxygenation tower inlet 8 on the deoxygenation tower 2, the deoxygenation tower outlet 9 on the deoxygenation tower 2 is connected to the first inlet 12, the first outlet 13 is connected to the adsorption tower inlet 15 of the adsorption tower 4, the adsorption tower outlet 16 of the adsorption tower 4 is connected to the second inlet 14 of the heat exchanger 3, and the second outlet 10 of the heat exchanger 3 is connected to the deuterium gas filling tank 18 through a pipeline.

[0034] A first detector 6 is provided on the top of the storage tank 1 for detecting the gas composition in the storage tank 1; a liquid outlet is provided at the bottom of the deoxygenation tower 2, and the liquid outlet is connected to the liquid recovery tank 11; a second detector 17 is provided on the pipeline connecting the heat exchanger 3 and the deuterium gas filling tank 18 for detecting the composition of the gas in the pipeline.

[0035] Before the purification reaction, the entire purification system is first evacuated and replaced to reduce the internal pressure of the system to below -0.099MPa, and then the entire purification system is replaced with helium. After the replacement is completed, the gas composition is detected by the first detector 6 and the second detector 17, and then the crude deuterium gas is filled into the storage tank 1 through the crude deuterium gas inlet 5. The crude deuterium gas enters the deoxidation tower 2 from the crude deuterium gas outlet 7 along the pipeline connected to the deoxidation tower inlet 8 to remove impurities such as O2, H2O, and CO2. The heavy water enters the liquid recovery tank 11 through the liquid outlet at the bottom of the deoxidation tower 2 for further recycling, and other gases are discharged from the deoxidation tower outlet 9. The deuterium gas coming out enters the heat exchanger 3 along the pipeline connected to the first inlet 12, and the deuterium gas entering the adsorption tower 4 is preheated. After the preheating is completed, the deuterium gas enters the adsorption tower inlet 15 at the bottom of the adsorption tower 4 along the first outlet 13 for deep impurity removal, and other impurities including N2, CO, THC in the deuterium gas are removed. Then, the deuterium gas enters the heat exchanger 3 through the second inlet 14 from the upper adsorption tower outlet 16 of the adsorption tower 4, and the deuterium gas is cooled in the heat exchanger 3. The deuterium gas after cooling is detected by the second detector on the pipeline connected to the second outlet 10, and the qualified high-purity deuterium gas enters the deuterium gas filling tank 18.

[0036] Example 1

[0037] A method for purifying semiconductor-grade ultra-high purity deuterium gas comprises the following steps:

[0038] The entire purification system was evacuated and replaced, and the internal pressure of the purification system was first reduced to below -0.099MPa, and then the purification system was replaced with 6N grade helium. After the replacement was completed, the impurity content of the system was tested at the analysis and detection point at the storage tank and the finished product outlet detection point. The background gas was helium. The test results are shown in Table 1;

[0039] The deuterium gas with a purity of 99.8% was collected in a storage tank with a working pressure of 0.8MPa. The indicators in the storage tank were analyzed and tested. The results of crude deuterium gas testing are shown in Table 2. After the testing, the deep purification stage was entered. The deoxygenation tower and adsorption tower were temperature-controlled before the deuterium gas was introduced. The temperature of the deep deoxygenation tower was controlled at 15°C, and the deuterium gas flow rate of the deep deoxygenation tower was controlled at 3Nm 3 / h, the temperature of the adsorption tower is first heated to 300℃, the gas coming out of the deep deoxygenation tower is preheated to 200℃, and then the adsorption tower is heated at a rate of 40℃ / h to stabilize the temperature of the adsorption tower at 350℃, and the heavy water produced in the deoxygenation process is recovered.

[0040] After the purification process stabilized, the product deuterium gas was tested and the purity of the collected deuterium gas reached 99.9998%. The contents of the main impurities in the finished product are shown in Table 3, and the yield of deuterium gas is 99.9%.

[0041] Table 1 The content of various impurities after system replacement

[0042] Impurities <![CDATA[N2]]> <![CDATA[O2+Ar]]> CO <![CDATA[CO2]]> THC Moisture Content (ppmv) 0.01 0.01 0.02 0.03 0.02 0.02

[0043] Table 2 Crude deuterium gas detection results

[0044] Impurities <![CDATA[N2]]> <![CDATA[O2+Ar]]> CO <![CDATA[CO2]]> THC Moisture Content (ppmv) 86.45 11.73 1.22 3.14 1.83 2.02

[0045] Table 3 Deuterium gas test results of finished products

[0046]

[0047]

[0048] Example 2

[0049] A method for purifying semiconductor-grade ultra-high purity deuterium gas comprises the following steps:

[0050] The entire purification system was evacuated and replaced, and the internal pressure of the purification system was first reduced to below -0.099MPa, and then the purification system was replaced with 6N grade helium. After the replacement was completed, the impurity content of the system was tested at the analysis detection point at the storage tank and the finished product outlet detection point. The background gas was helium. The test results are shown in Table 4;

[0051] The crude deuterium gas with a purity of 99.81% was collected in a storage tank with a working pressure of 0.8MPa. The indicators in the storage tank were analyzed and tested. The results of the crude deuterium gas test are shown in Table 5. After the test, the deep purification stage was entered. The deoxygenation tower and adsorption tower were temperature-controlled before the deuterium gas was introduced. The temperature of the deep deoxygenation tower was controlled at 25°C, and the deuterium gas flow rate of the deep deoxygenation tower was controlled at 7Nm 3 / h, the temperature of the adsorption tower is first heated to 400℃, the gas coming out of the deep deoxygenation tower is preheated to 280℃, and then the adsorption tower is heated at a rate of 35℃ / h to stabilize the temperature of the adsorption tower at 450℃, and the heavy water produced in the deoxygenation process is recovered.

[0052] After the purification process stabilized, the deuterium gas product was tested and the purity of the collected deuterium gas reached 99.9998%. The content of the main impurities in the finished product is shown in Table 6. The yield of deuterium gas is 99.9%

[0053] Table 4 Content of various impurities after system replacement

[0054] Impurities <![CDATA[N2]]> <![CDATA[O2+Ar]]> CO <![CDATA[CO2]]> THC Moisture Content (ppmv) 0.01 0.01 0.02 0.03 0.01 0.02

[0055] Table 5 Crude deuterium gas detection results

[0056] Impurities <![CDATA[N2]]> <![CDATA[O2+Ar]]> CO <![CDATA[CO2]]> THC Moisture Content (ppmv) 44.53 23.72 10.42 8.72 1.03 8.43

[0057] Table 6 Deuterium gas detection results of finished products

[0058] Impurities <![CDATA[N2]]> <![CDATA[O2+Ar]]> CO <![CDATA[CO2]]> THC Moisture Content (ppmv) 0.01 0.01 Not detected Not detected 0.02 0.01

[0059] Example 3

[0060] A method for purifying semiconductor-grade ultra-high purity deuterium gas comprises the following steps:

[0061] The entire purification system was evacuated and replaced, and the internal pressure of the purification system was first reduced to below -0.099MPa, and then the purification system was replaced with 6N grade helium. After the replacement was completed, the impurity content of the system was tested at the analysis detection point at the storage tank and the finished product outlet detection point. The background gas was helium. The test results are shown in Table 7;

[0062] The crude deuterium gas with a purity of 99.85% was collected in a storage tank with a working pressure of 0.8MPa. The indicators in the storage tank were analyzed and tested. The results of the crude deuterium gas test are shown in Table 8. After the test, the deep purification stage was entered. The deoxygenation tower and adsorption tower were temperature-controlled before the deuterium gas was introduced. The temperature of the deep deoxygenation tower was controlled at 35°C, and the deuterium gas flow rate of the deep deoxygenation tower was controlled at 12Nm 3 / h, the temperature of the adsorption tower is first heated to 500℃, the gas coming out of the deep deoxygenation tower is preheated to 100℃, and then the adsorption tower is heated at a rate of 39℃ / h to stabilize the temperature of the adsorption tower at 550℃, and the heavy water produced in the deoxygenation process is recovered.

[0063] After the purification process stabilized, the product deuterium gas was tested and the purity of the collected deuterium gas reached 99.9998%. The contents of the main impurities in the finished product are shown in Table 9, and the yield of deuterium gas is 99.9%.

[0064] Table 7 Contents of various impurities after system replacement

[0065] Impurities <![CDATA[N2]]> <![CDATA[O2+Ar]]> CO <![CDATA[CO2]]> THC Moisture Content (ppmv) 0.01 0.01 0.02 0.01 0.02 0.02

[0066] Table 8 Crude deuterium gas detection results

[0067] Impurities <![CDATA[N2]]> <![CDATA[O2+Ar]]> CO <![CDATA[CO2]]> THC Moisture Content (ppmv) 2.13 9.46 1.13 0.23 0.03 5.64

[0068] Table 9 Deuterium gas detection results of finished products

[0069] Impurities <![CDATA[N2]]> <![CDATA[O2+Ar]]> CO <![CDATA[CO2]]> THC Moisture Content (ppmv) 0.01 0.01 Not detected Not detected 0.01 0.01

[0070] The above is only a preferred embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application has been disclosed as a preferred embodiment as above, it is not intended to limit the present application. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present application. However, any modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A semiconductor-grade ultra-high purity deuterium gas purification device, characterized in that: It comprises a storage tank (1), a deoxidation tower (2), a heat exchanger (3) and an adsorption tower (4); The storage tank (1) is provided with a crude deuterium gas inlet (5) and a crude deuterium gas outlet (7); the deoxidation tower (2) is provided with a deoxidation tower inlet (8) and a deoxidation tower outlet (9); the heat exchanger (3) is provided with a first inlet (12) and a first outlet (13) at both ends; the heat exchanger (3) is provided with a second inlet (14) and a second outlet (10) at the side; the adsorption tower (4) is provided with an adsorption tower inlet (15) at the bottom and an adsorption tower outlet (16) at the top; The crude deuterium gas outlet (7) on the storage tank (1) is connected to the deoxidation tower inlet (8) on the deoxidation tower (2), the deoxidation tower outlet (9) on the deoxidation tower (2) is connected to the first inlet (12), the first outlet (13) is connected to the adsorption tower inlet (15) at the bottom of the adsorption tower (4), the adsorption tower outlet (16) at the top of the adsorption tower (4) is connected to the second inlet (14) on the side of the heat exchanger (3), and the second outlet (10) on the side of the heat exchanger (3) is connected to the deuterium gas filling tank (18) through a pipeline.

2. The semiconductor-grade ultra-high purity deuterium gas purification device according to claim 1, characterized in that: A first detector (6) is provided on the top of the storage tank (1); a liquid outlet is provided at the bottom of the deoxygenation tower (2), and the liquid outlet is connected to a liquid recovery tank (11); a second detector (17) is provided on a pipeline connecting the heat exchanger (3) and the deuterium gas filling tank (18), and both the first detector (6) and the second detector (17) are used to detect gas components, and both the first detector (6) and the second detector (17) are gas chromatographs.

3. A method for purifying semiconductor-grade ultra-high purity deuterium gas, based on a semiconductor-grade ultra-high purity deuterium gas purification device according to any one of claims 1 to 2, characterized in that: Specifically, crude deuterium gas is introduced into a storage tank (1), and then enters a deoxygenation tower (2) for deoxygenation. The gas coming out of the deoxygenation tower (2) is preheated, and then enters an adsorption tower (4) for impurity removal, and finally ultra-high purity deuterium gas is obtained.

4. The method for purifying semiconductor-grade ultra-high purity deuterium gas according to claim 3, characterized in that: The purity of the crude deuterium gas is ≥99.8%.

5. The method for purifying semiconductor-grade ultra-high purity deuterium gas according to claim 3, characterized in that: The temperature of the deep deoxygenation is 15-60°C.

6. The method for purifying semiconductor-grade ultra-high purity deuterium gas according to claim 3, characterized in that: The temperature of the deep impurity removal is 350-650°C.

7. The method for purifying semiconductor-grade ultra-high purity deuterium gas according to claim 3, characterized in that: The gas flow rate of the deep deoxygenation is 3-15Nm 3 / h.

8. The method for purifying semiconductor-grade ultra-high purity deuterium gas according to claim 3, characterized in that: The preheating temperature is 100-280°C.

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