A maintenance system and method for a silicon-based precision filter for electronic special gases

Abstract

The application discloses a kind of silicon-based electronic special gas precision filter's overhauling system and method thereof, including filter body, the filter body includes shell and filter core arranged in shell, feed valve is connected with shell by feed pipeline, filter core discharge side is connected with discharge valve by discharge pipeline;Feed pipeline is used to supply material to filter body, first waste liquid interface is provided on feed pipeline;The bottom of the shell of the filter body is provided with second waste liquid interface;The top of the shell is connected with air inlet;Discharge pipeline is used to discharge material filtered by filter body, third waste liquid interface and detection interface are provided on discharge pipeline, discharge valve is provided on the discharge side of discharge pipeline;The present scheme reduces product flushing time, reduces flushing consumption of qualified products, improves overhauling efficiency and replacement effect, and reduces production cost.

Description

Technical Field

[0001] This invention belongs to the field of filter technology for silicon-based electronic specialty gases, and specifically relates to a maintenance system and method for a precision filter for silicon-based electronic specialty gases. Background Technology

[0002] Electronic-grade dichlorosilane, electronic-grade trichlorosilane, and electronic-grade silicon tetrachloride are the main silicon-based electronic specialty gases. They can be used as silicon sources for silicon epitaxial growth and large-scale integrated circuit silicon epitaxy. They are high-performance source materials for low-temperature silicon deposition, with wide applications and large demand. However, their product quality requirements are also quite stringent. Particulate matter in silicon-based electronic specialty gases can cause poor film uniformity and even short circuits, seriously affecting yield. Particle size control is essential for silicon-based electronic specialty gases, requiring the use of precision filters to remove particulate matter. Furthermore, silicon-based electronic specialty gases react with moisture to form hydrochloric acid and silica particles, which are highly corrosive. Therefore, after replacing the filter element of the precision filter, the entire filter system needs to be inspected and replaced.

[0003] In related technologies, the main difficulties in the maintenance and replacement of existing silicon-based electronic specialty gas precision filters are: ① Silicon-based electronic specialty gases are toxic, harmful, and highly corrosive, and the materials cannot be directly discharged into the air or purged and replaced; ② The current precision filter design is not fully compatible with silicon-based electronic gas products, and there are replacement dead zones inside the filter and inlet and outlet pipes. The pleated filter element has a large specific surface area, making it difficult to completely replace; ③ After the filter element is replaced, due to incomplete replacement, the particle size of the product will be significantly higher in the initial stage of use, affecting product quality. A large amount of product is required for rinsing. The maintenance of precision filters has a significant impact on product quality and production costs, and the adverse effects last for a long time. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention aims to provide a maintenance system and method for a precision filter for silicon-based electronic special gases.

[0005] One objective of this invention is to provide a maintenance system for a precision filter for silicon-based electronic special gases, comprising a filter body, the filter body including a housing and a filter element disposed within the housing, a feed valve connected to the housing via a feed pipe, and a filter element discharge side connected to the discharge valve via a discharge pipe.

[0006] The feed pipe is used to supply material to the filter body, and a first waste liquid interface is provided on the feed pipe;

[0007] The bottom of the filter body housing is provided with a second waste liquid interface; the top of the housing is connected to an air source interface;

[0008] The discharge pipe is used to discharge the material filtered by the filter body. A third waste liquid interface and a detection interface are provided on the discharge pipe, and a discharge valve is provided on the discharge side of the discharge pipe.

[0009] Waste liquid tank; the inlet of the waste liquid tank is connected to the first waste liquid interface, the second waste liquid interface and the third waste liquid interface respectively, and is used to store the waste liquid discharged from the corresponding waste liquid interface;

[0010] A protective air source is connected to the air source interface of the housing, and is used to supply and replace protective air to the filter body, the feed pipe, and the discharge pipe.

[0011] Particle size analyzer; connected to the detection interface on the discharge pipe, used to detect the particle size of the filtered material discharged through the discharge pipe;

[0012] A vacuum pump is connected to a first waste liquid interface, a second waste liquid interface, and a third waste liquid interface via pipelines, and is used to evacuate the filter body, the feed pipe, and the discharge pipe for replacement.

[0013] As a preferred embodiment, a first pressure gauge is installed on the feed pipe between the feed valve and the filter body, and a second pressure gauge is installed on the discharge pipe between the filter body and the discharge valve.

[0014] As a preferred embodiment, a first waste liquid valve is provided on the connecting pipe between the first waste liquid interface and the waste liquid tank.

[0015] A second waste liquid valve is installed on the connecting pipe between the second waste liquid interface and the waste liquid tank;

[0016] A third waste liquid valve is installed on the connecting pipe between the third waste liquid interface and the waste liquid tank.

[0017] As a preferred embodiment, the feed pipe and discharge pipe of the filter body are connected to a backup filter, the filter body and the backup filter are arranged in parallel, the feed end of the backup filter is provided with a backup feed valve connected to the feed pipe, and the discharge end of the backup filter is also provided with a backup discharge valve connected to the discharge pipe.

[0018] As a preferred embodiment, a displacement valve is provided between the protective gas source and the gas source interface of the housing.

[0019] As a preferred option, a test valve is installed between the particle size analyzer and the detection interface.

[0020] The second objective of this invention is to provide a method for repairing a precision filter for silicon-based electronic specialty gases, the specific steps of which are as follows:

[0021] Step 1: Close the feed valve and discharge valve of the filter body to completely press the material in the filter body and the inlet and outlet pipes into the waste liquid tank.

[0022] Step 2: Evacuate the filter body and its auxiliary pipelines using a vacuum pump;

[0023] Step 3: Pressurize the filter body and its auxiliary pipelines using a protective air source;

[0024] Step 4: Repeat steps 2 and 3 a predetermined number of times;

[0025] Step 5: Apply a slight positive pressure to the filter body using a protective air source. Under this slight positive pressure, quickly replace the filter element.

[0026] Step 6: Perform leak testing on the filter body after reinstalling the filter element;

[0027] Step 7: Evacuate the filter body and its auxiliary pipelines using a vacuum pump;

[0028] Step 8: Pressurize the filter body and its auxiliary pipelines using a protective air source;

[0029] Step 9: Repeat steps 7 and 8 a predetermined number of times;

[0030] Step 10: Evacuate the filter body using a vacuum pump and set aside for later use;

[0031] Step 11: Open the feed valve and the second waste liquid valve of the filter body, and close the replacement valve, test valve, first waste liquid valve, third waste liquid valve and discharge valve; flush the feed pipe and housing of the filter body.

[0032] Step 12: Open the feed valve and the third waste liquid valve of the filter body, and close the replacement valve, test valve, first waste liquid valve, second waste liquid valve and discharge valve to flush the filter element and discharge pipe of the filter body.

[0033] Step 13: Open the test valve and test the material filtered by the filter. If the test is qualified, open the discharge valve. If the test is not qualified, repeat steps 11 and 12 until the particle size test is qualified.

[0034] Preferably, in step four, steps two and three are repeated 5-10 times.

[0035] Preferably, in step nine, steps seven and eight are repeated 3-5 times.

[0036] Preferably, in step nine, the positive pressure in step five is 0.01 MPa to 0.05 MPa.

[0037] Compared with the prior art, the present invention has at least the following beneficial effects:

[0038] Firstly, this invention optimizes the structure of the filter maintenance system, increasing the number of replacement points during precision filter maintenance. Replacement of the precision filter's interior and its inlet / outlet pipes can be achieved without dead zones. Waste liquid valves are installed on the precision filter's inlet and outlet pipes to ensure thorough replacement, eliminating dead zones. Addressing the issue of toxic and harmful silicon-based electronic gases and the difficulty in thoroughly replacing the filter element, a vacuum pump is added during precision filter maintenance. This ensures efficient replacement of the internal materials before replacement and of any trace amounts of water and oxygen introduced after replacement, preventing product contamination during maintenance. The vacuum pump operation significantly improves the replacement effect for difficult-to-replace pleated filter elements. It can efficiently and thoroughly replace precision filters used for silicon-based electronic gases, avoiding increased particulate matter content and decreased product quality caused by filter element replacement. The maintenance effect is good, the amount of product liquid used for filter element washing is significantly reduced, and production costs are significantly lowered.

[0039] Secondly, this invention optimizes the filter maintenance process. By organically cooperating with the aforementioned maintenance system with a specific structure, it achieves thorough purging and replacement both before and after maintenance, avoiding fluctuations in product quality after precision filter maintenance and improving quality stability before and after maintenance. It can flush materials from the precision filter inlet pipe, the interior of the precision filter, the filter element, and the precision filter outlet pipe, preventing unqualified products from entering subsequent product pipelines. Through valve switching, the filter's inlet pipe and shell are flushed first, followed by flushing the filter's outlet pipe and filter element separately, improving the targeting of replacement locations and avoiding replacement dead zones during the maintenance process. Simultaneously, it significantly reduces product consumption caused by flushing the filter after precision filter maintenance. Compared to traditional maintenance methods, the consumption of qualified products decreases from 160L to 10L, with better product particle size indicators. It reduces product flushing time and the consumption of qualified products, improving maintenance efficiency and replacement effect, while also reducing waste liquid and lowering production costs. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the maintenance system of the present invention;

[0042] Figure 2 This is a diagram showing the internal structure of the filter body of the present invention;

[0043] The diagram is labeled as follows: 1. Filter body, 11. Housing, 12. Filter element, 13. Bolt, 14. Filter element base, 2. Waste liquid tank, 3. Protective air source, 4. Particle size analyzer, 5. Vacuum pump, 101. Feed valve, 102. Feed pipe, 103. Discharge pipe, 104. Discharge valve, 105. First pressure gauge, 106. Second pressure gauge, 201. First waste liquid valve, 202. Second waste liquid valve, 203. Third waste liquid valve, 301. Replacement valve, 401. Test valve, A. Material feeding direction, B. Material discharging direction. Detailed Implementation

[0044] The present invention will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0045] It should be noted that, unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "a," "an," or "the," and similar words used in the specification and claims of this patent application do not express a limitation of quantity, but rather indicate the presence of at least one. Terms such as "comprising" or "including" indicate that the elements or objects preceding "comprising" encompass the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects having the same function.

[0046] In precision filters used in silicon-based electronic specialty gases, the internal structure of these filters is complex, with many dead zones for replacement, and the filter element has a large specific surface area and many pleats. During the replacement process, the existing method is to use a conventional inert gas to purge from top to bottom. This method is difficult to clean the filter and filter element in a short time and will cause filter contamination and increase the particle size of the product. This will directly affect the quality of the subsequent filtered products. At the same time, in order to meet the filtration requirements, a large amount of product is needed to rinse the filter, which will increase the production cost. In view of this, this application proposes the following solution.

[0047] As shown in the figure, in a typical embodiment of the present invention, a maintenance system for a precision filter for silicon-based electronic special gases is provided, including a filter body 1, an inlet pipe 102, an outlet pipe 103, a waste liquid tank 2, a protective gas source 3, a particle size analyzer 4, and a vacuum pump 5. By rationally designing and connecting the interfaces of the waste liquid tank 2, the protective gas source 3, the particle size analyzer 4, and the vacuum pump 5 with the interfaces of each pipe, the number of replacement positions for the precision filter is increased, the replacement effect is improved, and the consumption of products for rinsing the filter is greatly reduced, resulting in a significant cost reduction.

[0048] In one embodiment of the present invention, the filter body 1 includes an upper housing 111, a lower housing 112, and a filter element 12. The ports of the upper housing 111 and the lower housing 112 are connected to form a relatively sealed housing space and are fastened by bolts 13. The filter element 12 is located in the housing space. In this embodiment, the filter element 12 can be a folded filter element. The port of the filter element 12 is connected to the filter element base 14 at the feed end of the discharge pipe 104. The feed end of the discharge pipe 103 extends into the filter from the lower housing 112 and is connected to the port of the filter element 12. The lower housing 112 is connected to the feed valve 101 through the feed pipe 102. The top of the upper housing 111 is also provided with an air source interface N3, and the bottom of the lower housing 112 is also provided with a second waste liquid discharge port N4. Liquid material enters the filter housing 1 through the feed valve 101 and feed pipe 102, and enters the filter element 12 from the outside of the filter element 12. Finally, it can be discharged through the discharge pipe 103 and discharge valve 104.

[0049] In this design, the precision filter is made of 316L stainless steel, with an internal volume of 2L to 20L. The filter housing is electrolytically polished, and the housing body is flange-sealed, with flange sizes ranging from DN100 to DN300 and pressure ratings from 1.0MPa to 2.5MPa. The sealing ring or gasket is made of PTFE. There are 1 to 5 filter elements, each 10in to 20in in length, made of PTFE or PFA. Filter element 12 is a microporous pleated membrane filter with a filtration accuracy of 0.03μm to 0.2μm. A dry-based filter element is used. Liquid material enters from the outside of filter element 12 and then enters the filtered pipeline from the inside of filter element 12, with a material flow rate of 10L / h to 200L / h.

[0050] In one embodiment of the present invention, a first waste liquid interface N1 is provided on the feed pipe 102 between the feed valve 101 and the filter body 1. The first waste liquid interface N1 is connected to the waste liquid tank 2 through a first waste liquid valve 201. The first waste liquid valve 201 can be set close to the first waste liquid interface to avoid dead zones as much as possible. A second waste liquid interface N4 is provided at the bottom of the lower housing 112 of the filter. The second waste liquid interface N4 is connected to the waste liquid tank 2 through a second waste liquid valve 202. The outlet is located between the filter body 1 and the discharge valve 104. A third waste liquid inlet N2 is provided on the material pipeline 103. The third waste liquid inlet N2 is connected to the waste liquid tank 2 through the third waste liquid valve 203. Preferably, the waste liquid pipelines containing the first waste liquid valve 201, the second waste liquid valve 202, and the third waste liquid valve 203 are all connected to the waste liquid inlet of the waste liquid tank 2. The pressure of the waste liquid tank 2 is controlled between 0.05MPa and 0.2MPa. The lower pressure is to ensure that the waste liquid can be forced from the filter to the waste liquid tank under certain pressure. If the pressure is too high, it will be detrimental to the discharge of waste liquid. The waste liquid tank 2 is used to store the waste liquid discharged through the first waste liquid valve 201, the second waste liquid valve 202, and the third waste liquid valve 203. It should be noted that the waste liquid inlet of waste liquid tank 2 is also equipped with an inlet master valve (not shown in the figure). The inlet master valve can ensure that waste liquid tank 2 is isolated when the vacuum pump is drawing a vacuum. Of course, the vacuum pump 5 is also equipped with a vacuum master valve (not shown in the figure). This design ensures that waste liquid will not be accidentally discharged into vacuum pump 5 when it is discharged.

[0051] In this design, a vacuum interface is installed on the waste liquid pipeline of the waste liquid tank 2. The vacuum interface is connected to the vacuum pump 5, and the vacuum degree can reach 10Pa to 100Pa. Due to the strong corrosiveness of silicon-based electronic gas, a dry pump is preferred. The vacuum pump 5 can be connected to the first waste liquid interface, the second waste liquid interface and the third waste liquid interface through pipelines, and can be used to evacuate the auxiliary pipelines such as the filter body 1, the feed pipeline 102 and the discharge pipeline 103 for replacement.

[0052] In this design, a protective gas source interface N3 is provided on the top of the upper shell 111. The protective gas source interface N3 is connected to the protective gas source 3 through a displacement valve 301 and a gas source pipeline. The protective gas source 3 can use high-purity gas. The high-purity inert gas can be nitrogen, argon or helium as needed. The purity of the high-purity inert gas is ≥5N, the moisture content is ≤10ppb, and the oxygen content is ≤10ppb. Its pressure is adjustable and the pressure range is 0.01MPa~1MPa.

[0053] In a typical embodiment of the present invention, a detection interface is provided on the discharge pipe 102. The detection interface is connected to the particle size analyzer 4 through the test valve 401 and the test pipe. The particle size analyzer 4 is used to detect the particle size of the filtered material discharged through the filter discharge pipe. The particle size analyzer 4 has a test flow rate of 10mL / min to 20mL / min and measures the particle size range of 0.1μm to 0.5μm.

[0054] In this design, a first pressure gauge 105 is installed at the inlet port N5 of the feed pipe 102, and a second pressure gauge 106 is installed at the outlet port N5 of the discharge pipe 103. The first pressure gauge 105 and the second pressure gauge 106 are used to detect the pressure on the corresponding pipes. The display range of the first and second pressure gauges 105 and 106 is -0.1MPa to 1MPa.

[0055] In this solution, the piping used in the filtration and maintenance system is 316L EP piping, and the valves used are high-purity membrane valves with MVCR sealing.

[0056] In one embodiment of the present invention (not shown), to ensure the stable and continuous operation of the system, the precision filter can be configured as a standby filter. The standby filter is connected in parallel with the filter body 1. The standby filter's inlet end is equipped with a standby inlet valve connected to the pre-valve pipe of inlet valve 101, and the standby filter's outlet end is also equipped with a standby outlet valve connected to the post-valve pipe of outlet valve 104. Furthermore, the standby filter system can adopt the same piping connection method as the filter maintenance system, further reducing the impact on the continuous and stable operation of production.

[0057] This invention also provides a method for overhauling a precision filter for silicon-based electronic specialty gases, the specific steps of which are as follows:

[0058] Step 1: Close the feed valve 101 and discharge valve 104 of the filter body 1 to completely press the material in the filter body 1 and the inlet and outlet pipes 102 and 103 into the waste liquid tank 2.

[0059] The conditions for overhauling the precision filter are: the pressure difference across the filter is greater than 50 kPa or the particle size of the material after filtration is found to be unqualified; close the feed valves 101 and discharge valves 104 before and after the filter body 1, open the first waste liquid valve 201, the second waste liquid valve 202, and the third waste liquid valve 203, open the replacement valve 301 connected to the air source interface at the top of the filter body 1, and by continuously filling inert gas, completely pressurize the material in the precision filter housing and its inlet and outlet pipes into the waste liquid tank 2.

[0060] Step 2: Evacuate the filter body 1 and its connected auxiliary pipes using vacuum pump 5;

[0061] Opening the first waste liquid valve 201, the second waste liquid valve 202, and the third waste liquid valve 203 connects the vacuum pipeline to the filter body 1. At this time, since the feed valve 101 and the discharge valve 104 before and after the filter body 1 are closed, and the replacement valve 301 and the test valve 401 are also closed, the vacuum pump 4 is turned on to reduce the pressure of the filter body 1 and the auxiliary pipeline to 30Pa~100Pa.

[0062] Step 3: Pressurize the filter body 1 and its connected auxiliary pipes using the protective air source 3;

[0063] Close the first waste liquid valve 201, the second waste liquid valve 202, and the third waste liquid valve 203, introduce inert gas, and increase the pressure of the filter body 1 and auxiliary pipelines to 0.3MPa~0.7MPa to perform internal replacement of the filter body 1.

[0064] Step 4: Repeat steps 2 and 3 a predetermined number of times;

[0065] Repeat step two again, using vacuum pump 5 to draw negative pressure, and step three, using inert gas to fill with positive pressure. Repeat this process 5 to 10 times to ensure that the inside of the precision filter housing, the inlet and outlet pipes 102 and 103, and the filter element 12 are thoroughly replaced.

[0066] Step 5: Press the filter body 1 with a slight positive pressure of 0.01MPa to 0.05MPa through the protective air source 3. Under the slight positive pressure, quickly replace the filter element.

[0067] At this point, open the connecting bolts of the upper and lower housings 111 and 112, and disassemble the upper housing 111 of the filter. Since the displacement valve 301 is open, the upper housing 111 has a certain inert gas protection. After quickly replacing the filter element 12, reinstall the upper housing 111 to prevent a large amount of air from entering and contaminating the upper housing 111 of the filter. This replacement method can reduce the time of air exposure inside the filter.

[0068] Step 6: Check the filter for leaks;

[0069] After filter element 12 is reinstalled, the precision filter is leak-tested. Under positive pressure of 1MPa and negative pressure of -0.1MPa, the pressure is maintained for 1 hour each. According to the Clapeyron equation: leakage rate S = (1 - P2T1 / P1T2) × 100%, where: P1 represents the system pressure at the beginning of the test, P2 represents the system pressure at the end of the test, T1 represents the system temperature at the beginning of the test, and T2 represents the system temperature at the end of the test. S < 0.5% is considered to be qualified for pressure maintenance.

[0070] Step 7: Evacuate the filter body 1 and its connected auxiliary pipes using vacuum pump 5;

[0071] Before use, the precision filter needs to be completely replaced with trace amounts of water and oxygen during air purging. The vacuum pump 5 is turned on to reduce the pressure of the filter body 1 and its auxiliary pipeline to 30Pa to 100Pa. Specifically, the first waste liquid valve 201, the second waste liquid valve 202, and the third waste liquid valve 203 are opened to connect the vacuum pipeline and the filter body 1. At this time, since the feed valve 101 and the discharge valve 104 before and after the filter are closed, and the replacement valve 301 and the test valve 401 are also closed, the vacuum pump 5 is turned on to reduce the pressure of the precision filter and its connected auxiliary pipeline to 30Pa to 100Pa.

[0072] Step 8: Pressurize the filter body 1 and its connected auxiliary pipes using the protective air source 3;

[0073] Close the first waste liquid valve 201, the second waste liquid valve 202, and the third waste liquid valve 203. The feed valve 101, the discharge valve 104, and the test valve 401 are all closed. Open the replacement valve 301 to introduce inert gas and increase the pressure of the precision filter and auxiliary pipeline to 0.3MPa to 0.7MPa to perform internal replacement of the filter.

[0074] Step 9: Repeat steps 7 and 8 a predetermined number of times;

[0075] Again, use step seven to draw negative pressure with vacuum pump 5, and use step eight to fill positive pressure with inert gas. Repeat this process of blowing and purging 3 to 5 times to ensure that the inside of the precision filter, the inlet and outlet pipes 102 and 103, and the filter element 12 are thoroughly replaced and cleaned.

[0076] Step 10: Evacuate the filter body 1 using vacuum pump 2, and set it aside for later use;

[0077] Opening the first waste liquid valve 201, the second waste liquid valve 202, and the third waste liquid valve 203 connects the vacuum pipeline to the filter body 1. The feed valve 101, discharge valve 104, replacement valve 301, and test valve 401 are all closed. The vacuum pump 5 is then turned on, reducing the pressure in the precision filter and auxiliary pipelines to 30Pa–100Pa. Once the conditions for commissioning are met, the first waste liquid valve 201, the second waste liquid valve 202, and the third waste liquid valve 203 are closed.

[0078] Step 11: Open the filter's feed valve 101 and the second waste liquid valve 202. The replacement valve 301, test valve 401, first waste liquid valve 201, third waste liquid valve 203, and discharge valve 104 are closed. Flush the filter's feed pipe 102 and housing 11.

[0079] Open the precision filter feed valve 101 to allow material to enter the filter. Once the filter is full, open the second waste liquid valve 202 to flush the feed pipe 102 and housing 11 of the filter body 1. After flushing with 5L to 20L of material, close the second waste liquid valve 202.

[0080] Step 12: Open the feed valve 101 and the third waste liquid valve 203 of the filter, and close the replacement valve 301, test valve 401, first waste liquid valve 201, second waste liquid valve 202 and discharge valve 104 to flush the filter element 12 and discharge pipe 103; after flushing 5L to 20L of material, close the third waste liquid valve 203; the amount of material flushed is directly related to the filter volume and the number of filter elements. If the filter volume is large and the number of filter elements is large, more material will be flushed, and vice versa.

[0081] Step 13: Open test valve 401 to test the material filtered by the filter.

[0082] If the material passes the test, open the discharge valve 104 to discharge it. If the material fails the test, repeat steps eleven and twelve until the particle size test is passed.

[0083] The material enters the particle size analyzer 4, and the feed flow rate is controlled at 10mL / min to 20mL / min to test the particle size of the filtered material. After the particle size test is qualified, the discharge valve 104 after the filter is opened, and the material is supplied to the next process normally. If the particle size is too high, the filter flushing steps eleven and twelve are repeated several times until the particle size is qualified.

[0084] The following description is based on specific embodiments.

[0085] Example 1

[0086] The precision filter is made of 316L stainless steel with a volume of 3L. The interior is electropolished. The housing (11) is flange-sealed, DN100, PN1.6MPa, and the sealing ring is made of PTFE. The filter element (12) is a microporous pleated membrane filter with a filtration accuracy of 0.05μm, one piece per unit, 10in in length, and made of PTFE. The high-purity inert gas is nitrogen with a purity ≥5N, moisture ≤10ppb, and oxygen ≤10ppb. The vacuum pump is a dry pump with a vacuum degree of 30Pa. The particle size analyzer measures a flow rate of 10mL / min. The filter medium is electronic-grade silicon tetrachloride with a flow rate of 20L / h. Before maintenance, the filter was replaced 10 times using a protective gas source and vacuum pump. During filter element replacement, the high-purity nitrogen protective pressure was 0.05 MPa. After maintenance, the filter was held at 1 MPa for 1 hour with a leakage rate S1 = 0.2%, and at -0.1 MPa for 1 hour with a leakage rate S2 = 0.35%, both meeting the requirements. After maintenance, the filter was replaced 5 times using a protective gas source and vacuum pump. The second waste liquid valve 202 was opened to flush the filter inlet pipe 102 and filter housing 11, flushing with 5L of material. The third waste liquid valve 203 was opened to flush the filter element 12 and the filter outlet pipe 103, flushing with 5L of material. The feed flow rate of the particle size analyzer 4 was controlled at 10 mL / min. The particle size of the precision filter before and after maintenance was tested using a RION KS-16F particle size analyzer from Japan, specifically following the maintenance methods described in steps one through thirteen.

[0087] Comparative Example 1

[0088] Comparative Example 1 uses a traditional maintenance method, with all other conditions identical to Example 1. The difference lies in that: inert gas is introduced into the top replacement valve 301 of the precision filter; material is expelled from the precision filter and the filter element 12 is replaced only through the second waste liquid valve 202; there is no vacuum pump for purging; and the inlet and outlet pipes of the precision filter are not effectively flushed or replaced before and after the filter element 12 is replaced. It should be noted that the maintenance system before the improvement did not include the installation of the first waste liquid valve 201, the third waste liquid valve 203 and their corresponding pipes, or the vacuum pump 5. Therefore, in this comparative example, the first waste liquid valve 201 and the third waste liquid valve 203 are always closed before and after maintenance, and the vacuum pump 5 is always turned off to maintain consistency with the maintenance system before the improvement.

[0089] The specific maintenance methods before the improvement are as follows:

[0090] Step 1: Close the feed valve 101 and discharge valve 104 of the filter body 1, and press the material in the filter body 1 into the waste liquid tank 2 through the second waste liquid valve 202. The conditions for maintenance of the precision filter are: the pressure difference before and after the filter is >50kPa or the particle size of the material after filtration is unqualified. Close the feed valve 101 and discharge valve 104 of the filter body 1, open the second waste liquid valve 202, open the replacement valve 301 connected to the air source interface at the top of the filter body 1, and press the material in the precision filter housing into the waste liquid tank 2 by continuously filling inert gas.

[0091] Step 2: Filter replacement. Open the connecting bolts of the upper and lower housings 111 and 112, remove the upper housing 111 of the filter, and quickly replace the filter element 12. Open the replacement valve 301. The upper housing 111 has a certain amount of inert gas protection. After quickly replacing the filter element 12, reinstall the upper housing 111 to prevent a large amount of air from entering and contaminating the upper housing 111 of the filter. This replacement method can reduce the time that the filter is exposed to air.

[0092] Step 3: Leak test the filter; after reinstalling filter element 12, leak test the precision filter. Under positive pressure of 1MPa and negative pressure of -0.1MPa, the filter is tested for leaks and the pressure is maintained for 1 hour each.

[0093] Step 4: Rinsing

[0094] Open the filter's feed valve 101 and second waste liquid valve 202; the replacement valve 301, test valve 401, first waste liquid valve 201, third waste liquid valve 203, and discharge valve 104 are closed; flush the filter's feed pipe 102 and housing 11.

[0095] Specifically: Open the precision filter feed valve 101, and the material enters the filter. After the material is full, open the second waste liquid valve 202 to flush the waste liquid tank 2, and flush the feed pipe 102 and housing 11 of the filter body 1. After flushing 10L of material, close the second waste liquid valve 202.

[0096] Step 5: Open test valve 401 to test the material filtered by the filter. The material enters particle size analyzer 4. The particle size analyzer test rate is controlled at 10 mL / min to test the particle size of the filtered material.

[0097] Table 1 Comparison of particle size data between Example 1 and Comparative Example 1

[0098]

[0099]

[0100] In Table 1, Sample 1 is the particle size data of the precision filter during normal operation, Sample 2 is the particle size data of the precision filter before maintenance, Sample 3 is the particle size data of the precision filter of Example 1 after maintenance according to the device and method of the present invention, and Sample 4 is the particle size data after maintenance using conventional maintenance methods.

[0101] As can be seen from Table 1, the method of this invention for repairing the precision filter did not cause a significant change in the particle size of the product, and had no significant impact on product quality, demonstrating good results. In contrast, the particle size data of Comparative Example 1, which used a conventional repair method, showed a significant change, which would adversely affect product quality.

[0102] Example 2

[0103] Under the same conditions as in Example 1, Sample 1 was repaired using the repair method of Example 1. The second waste liquid valve 202 was opened, and the flushing volume of the filter inlet pipe 102 and the filter housing 11 was 5L; the third waste liquid valve 203 was opened, and the flushing volume of the filter element 12 and the filter outlet pipe 103 was 5L.

[0104] Example 3

[0105] The conditions are the same as in Example 1, except that: when the second waste liquid valve 202 is opened, the flushing volume of the filter feed pipe 102 and the filter housing 11 is 10L; when the third waste liquid valve 203 is opened, the flushing volume of the filter element 12 and the filter discharge pipe 103 is 10L.

[0106] Example 4

[0107] The conditions are the same as in Example 1, except that: when the second waste liquid valve 202 is opened, the flushing volume of the filter inlet pipe 102 and the filter housing 11 is 20L; when the third waste liquid valve 203 is opened, the flushing volume of the filter element 12 and the filter outlet pipe 103 is 20L.

[0108] Example 5

[0109] The conditions are the same as in Example 1, except that: when the second waste liquid valve 202 is opened, the flushing volume of the filter feed pipe 102 and the filter housing 11 is 3L; when the third waste liquid valve 203 is opened, the flushing volume of the filter element 12 and the filter discharge pipe 103 is 3L.

[0110] Example 6

[0111] The conditions are the same as in Example 1, except that: when the second waste liquid valve 202 is opened, the flushing volume of the filter feed pipe 102 and the filter housing 11 is 1L; when the third waste liquid valve 203 is opened, the flushing volume of the filter element 12 and the filter discharge pipe 103 is 1L.

[0112] Comparative Example 2

[0113] The conditions are the same as in Example 1, except that after the filter element 12 is replaced and replaced, the second and third waste liquid valves 202 and 203 are not opened for flushing. The filter is put into use and tested directly. That is, after step nine of the aforementioned improved maintenance method, steps eleven, twelve and thirteen are omitted.

[0114] Table 2 Comparison of particle size data between Examples 2-6 and Comparative Example 2

[0115]

[0116] In Table 2, Sample 1 was repaired using the repair method of Example 1, with a flushing volume of 5L for the filter inlet pipe 102 and filter housing 11, and a flushing volume of 5L for the filter element 12 and post-filter outlet pipe 103; Sample 2 had a flushing volume of 10L for the filter inlet pipe 102 and filter housing 11, and a flushing volume of 10L for the filter element 12 and post-filter outlet pipe 103; Sample 3 had a flushing volume of 20L for the filter inlet pipe 102 and filter housing 11, and a flushing volume of 20L for the filter element 12 and post-filter outlet pipe 103; Sample 4 had a flushing volume of 3L for the filter inlet pipe 102 and filter housing 11, and a flushing volume of 3L for the filter element 12 and post-filter outlet pipe 103; Sample 5 had a flushing volume of 1L for the filter inlet pipe 102 and filter housing 11, and a flushing volume of 1L for the filter element 12 and post-filter outlet pipe 103; Sample 6 was used directly without flushing and was tested.

[0117] As can be seen from the comparison in Table 2, the more thoroughly the precision filter and its inlet and outlet pipes 102 and 103 are rinsed, the lower the particle size of the product. However, excessive rinsing will increase production costs. Based on the experimental results of different precision filters, the appropriate product rinsing amount should be selected.

[0118] Example 7

[0119] The conditions were the same as those in Example 1. Sample 1 was repaired using the repair method in Example 1. Before the filter element was replaced, it was blown and replaced 10 times, and after the repair, it was blown and replaced 5 times.

[0120] Example 8

[0121] The other conditions are the same as those in Example 1, except that: before maintenance, the pumping and purging were performed 20 times, and after maintenance, the pumping and purging were performed 10 times.

[0122] Example 9

[0123] The other conditions are the same as those in Example 1, except that: before maintenance, the pumping and purging were performed 5 times, and after maintenance, the pumping and purging were performed 3 times.

[0124] Example 10

[0125] The other conditions are the same as those in Example 1, except that: before maintenance, the pumping and purging were performed 3 times, and after maintenance, the pumping and purging were performed 2 times.

[0126] Example 11

[0127] The other conditions are the same as those in Example 1, except that: the pumping and purging is performed once before the maintenance and once after the maintenance.

[0128] Comparative Example 3

[0129] The other conditions are the same as those in Example 1, except that: after the liquid material was compressed before the maintenance, no protective gas was purged; and after the nitrogen pressure was qualified after the filter was maintained, no purging was performed.

[0130] Table 3 Comparison of particle size data between Examples 7-11 and Comparative Example 3

[0131]

[0132] In Table 3, Sample 1 was repaired using the repair method of Example 1, with 10 purges and purgings before repair and 5 purges and purgings after repair; Sample 2 was purges and purgings 20 times before repair and 10 times after repair; Sample 3 was purges and purgings 5 ​​times before repair and 3 times after repair; Sample 4 was purges and purgings 3 times before repair and 2 times after repair; Sample 5 was purges and purgings 1 time before repair and 1 time after repair; Sample 6 was purges and purgings were not performed after the liquid material was compressed before repair, and the nitrogen pressure was qualified after the filter was repaired and reinstalled, but no purges were performed.

[0133] As can be seen from Table 3, pre-maintenance blowing can thoroughly replace materials with high particle size, while post-maintenance blowing can replace trace amounts of water and oxygen during filter maintenance, preventing them from reacting with electronic-grade silicon tetrachloride to produce SiO2 particles. If effective blowing and replacement cannot be performed, the product particle size will be significantly higher.

[0134] Example 12

[0135] The maintenance conditions were the same as in Example 1. After maintenance, the system was put into normal operation. The flow rate of electronic-grade silicon tetrachloride was 20L / h. After a period of operation, samples were taken. The filter was flushed for 2 hours through the feed valve 101 and the discharge valve 104 before sampling and testing.

[0136] Example 13

[0137] The maintenance conditions were the same as in Example 1. After maintenance, the system was put into normal operation. The flow rate of electronic-grade silicon tetrachloride was 20L / h. After a period of operation, samples were taken. The filter was flushed for 4 hours through the feed valve 101 and the discharge valve 104 before sampling and testing.

[0138] Example 14

[0139] The maintenance conditions were the same as in Example 1. After maintenance, the system was put into normal operation. The flow rate of electronic-grade silicon tetrachloride was 20L / h. After a period of operation, samples were taken. The filter was flushed for 8 hours through the feed valve 101 and the discharge valve 104 before sampling and testing.

[0140] Comparative Example 4

[0141] Similar to other maintenance conditions in Example 1, the difference lies in that the filter was put into operation without undergoing suction blowing and material flushing during maintenance. Sampling was performed after a period of operation. After the filter element was reinstalled, the discharge valve 104 was directly opened to begin flushing, and samples were taken for testing after 2 hours of flushing. The entire process only involved opening the replacement valve 301 and the third waste liquid valve 203 at the beginning to discharge the material from the filter. Throughout the process, the first waste liquid valve 201, the third waste liquid valve 203, their respective pipelines, and the vacuum pump 5 were closed. No testing was performed; flushing was directly initiated by opening the feed valve 101 and the discharge valve 104. Steps two, three, and four (pre-maintenance suction blowing), steps seven, eight, nine, and ten (post-maintenance suction blowing), steps eleven and twelve (flushing), and step thirteen (testing) of this scheme were omitted. After direct operation, the feed valve 101 and discharge valve 104 were opened to flush the filter for 2 hours before sampling and testing.

[0142] Before and after the maintenance of this comparative example, the first waste liquid valve 201 and the third waste liquid valve 203 were always closed, and the vacuum pump 5 was always shut off, so as to maintain consistency with the maintenance system before the improvement.

[0143] The specific maintenance methods are as follows:

[0144] Step 1: Close the feed valve 101 and discharge valve 104 of the filter body 1, and press the material in the filter body 1 into the waste liquid tank 2 through the second waste liquid valve 202; close the feed valve 101 and discharge valve 104 of the filter body 1, open the second waste liquid valve 202, open the replacement valve 301 connected to the air source interface at the top of the filter body 1, and press the material in the precision filter housing into the waste liquid tank 2 by continuously filling inert gas.

[0145] Step 2: Filter replacement. Open the connecting bolts of the upper and lower housings 111 and 112, remove the upper housing 111 of the filter, and quickly replace the filter element 12. Open the replacement valve 301. The upper housing 111 has a certain amount of inert gas protection. After quickly replacing the filter element 12, reinstall the upper housing 111 to prevent a large amount of air from entering and contaminating the upper housing 111 of the filter. This replacement method can reduce the time that the filter is exposed to air.

[0146] Step 3: Leak test the filter; after reinstalling filter element 12, leak test the precision filter. Hold the pressure for 1 hour under positive pressure of 1MPa and negative pressure of -0.1MPa respectively.

[0147] Step 4: With replacement valve 301, test valve 401, first waste liquid valve 201, second waste liquid valve 202, and third waste liquid valve 203 in the closed state, the filter is flushed by opening the feed valve 101 and the discharge valve 104.

[0148] Comparative Example 5

[0149] The maintenance conditions were the same as those in Comparative Example 4, except that: after a period of operation, samples were taken, and the filter was flushed for 4 hours by opening the feed valve 101 and the discharge valve 104 before sampling and testing.

[0150] Comparative Example 6

[0151] The maintenance conditions were the same as those in Comparative Example 4, except that after the filter was put into use for a period of time, samples were taken, and the filter was flushed for 8 hours by opening the feed valve 101 and the discharge valve 104 before sampling and testing.

[0152] Table 4 Comparison of particle size data between Examples 12-14 and Comparative Examples 4-6

[0153]

[0154] In Table 4, Samples 1, 2, and 3 were repaired using the repair method of Example 1 and put into normal operation after repair. The flow rate of electronic-grade silicon tetrachloride was 20 L / h. Samples were taken after a period of operation. Sample 1 was rinsed for 2 hours, Sample 2 for 4 hours, and Sample 3 for 8 hours. Samples 4, 5, and 6 were put into operation without purging and material rinsing after filter repair. Samples were taken after a period of operation. Sample 4 was rinsed for 2 hours, Sample 5 for 4 hours, and Sample 6 for 8 hours.

[0155] As shown in Table 4, after the precision filter was repaired and put into use using this invention, the particle size of the product decreased after dynamic rinsing with the product, but stabilized after rinsing for 4 hours. If only ordinary methods were used for repair, a longer time and a large amount of material would be required for rinsing and replacement. After rinsing for 8 hours and consuming 160L of product, the particle size index of the product could be qualified, but the time was significantly extended and the cost was significantly increased.

[0156] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0157] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0158] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0159] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0160] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0161] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A maintenance system for a precision filter for silicon-based electronic specialty gases, characterized in that: The filter body includes a housing and a filter element disposed within the housing. A feed valve is connected to the housing via a feed pipe, and the filter element discharge side is connected to the discharge valve via a discharge pipe. The feed pipe is used to supply material to the filter body. A first waste liquid interface is provided on the feed pipe, which is located between the feed valve and the filter body. The bottom of the filter body housing is provided with a second waste liquid interface; the top of the housing is connected to an air source interface; The discharge pipe is used to discharge the material filtered by the filter body. A third waste liquid interface and a detection interface are provided on the discharge pipe. A discharge valve is provided on the discharge side of the discharge pipe. The third waste liquid interface is located between the discharge valve and the filter body. Waste liquid tank; the inlet of the waste liquid tank is connected to the first waste liquid interface, the second waste liquid interface and the third waste liquid interface respectively, and is used to store the waste liquid discharged from the corresponding waste liquid interface; A protective air source is connected to the air source interface of the housing, and is used to supply and replace protective air to the filter body, the feed pipe, and the discharge pipe. Particle size analyzer; The detection interface connected to the discharge pipe is used to detect the particle size of the filtered material discharged through the discharge pipe. A vacuum pump, which is connected to a first waste liquid interface, a second waste liquid interface and a third waste liquid interface through pipelines, is used to evacuate the filter body, the feed pipe and the discharge pipe for replacement. A displacement valve is provided between the protective gas source and the gas source interface of the housing; A test valve is installed between the particle size analyzer and the detection interface; A first waste liquid valve is installed on the connecting pipe between the first waste liquid interface and the waste liquid tank. A second waste liquid valve is installed on the connecting pipe between the second waste liquid interface and the waste liquid tank; A third waste liquid valve is installed on the connecting pipe between the third waste liquid interface and the waste liquid tank.

2. The maintenance system for a silicon-based electronic specialty gas precision filter according to claim 1, characterized in that: A first pressure gauge is installed on the feed pipe between the feed valve and the filter body, and a second pressure gauge is installed on the discharge pipe between the filter body and the discharge valve.

3. The maintenance system for a precision filter for silicon-based electronic special gases according to claim 1, characterized in that: The filter body has a feed pipe and a discharge pipe connected to a backup filter. The filter body and the backup filter are arranged in parallel. The feed end of the backup filter is equipped with a backup feed valve connected to the feed pipe, and the discharge end of the backup filter is also equipped with a backup discharge valve connected to the discharge pipe.

4. A maintenance method for a maintenance system for a silicon-based electronic specialty gas precision filter according to any one of claims 1-3, characterized in that: The specific steps are as follows: Step 1: Close the feed valve and discharge valve of the filter body to completely press the material in the filter body and the inlet and outlet pipes into the waste liquid tank. Step 2: Evacuate the filter body and its auxiliary pipelines using a vacuum pump; Step 3: Pressurize the filter body and its auxiliary pipelines using a protective air source; Step 4: Repeat steps 2 and 3 a predetermined number of times; Step 5: Apply a slight positive pressure to the filter body using a protective air source. Under this slight positive pressure, quickly replace the filter element. Step 6: Perform leak testing on the filter body after reinstalling the filter element; Step 7: Evacuate the filter body and its auxiliary pipelines using a vacuum pump; Step 8: Pressurize the filter body and its auxiliary pipelines using a protective air source; Step 9: Repeat steps 7 and 8 a predetermined number of times; Step 10: Evacuate the filter body using a vacuum pump and set aside for later use; Step 11: Open the feed valve and the second waste liquid valve of the filter body, and close the replacement valve, test valve, first waste liquid valve, third waste liquid valve and discharge valve; flush the feed pipe and housing of the filter body. Step 12: Open the feed valve and the third waste liquid valve of the filter body, and close the replacement valve, test valve, first waste liquid valve, second waste liquid valve and discharge valve to flush the filter element and discharge pipe of the filter body. Step 13: Open the test valve and test the material filtered by the filter. If the test is qualified, open the discharge valve. If the test is not qualified, repeat steps 11 and 12 until the particle size test is qualified.

5. The maintenance method according to claim 4, characterized in that: In step four, steps two and three are repeated 5-10 times.

6. The maintenance method according to claim 4 or 5, characterized in that: In step nine, steps seven and eight are repeated 3-5 times.

7. The maintenance method according to claim 4, characterized in that: In step five, the positive pressure is 0.01 MPa to 0.05 MPa.

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