A high-stability semiconductor-process ultrapure water supply system

Abstract

This utility model discloses a high-stability ultrapure water supply system for semiconductor processes, relating to the field of water treatment technology in semiconductor manufacturing. It aims to solve the problems of long recovery time and significant waste of ultrapure water quality after fault repair. The system includes a water tank body with a high-purity nitrogen inlet pipe and an ultrapure water delivery pipe at the top. The side walls are equipped with an overflow pipe, an ultrapure water outlet pipe, and an auxiliary pipe with an exhaust valve. An exhaust pipe with an exhaust valve is also located at the top. A liquid-sealing mechanism containing a liquid-sealed water tank is located on one side of the water tank body. The exhaust pipe / overflow pipe extends below the water surface in the liquid-sealed water tank via an extension pipe. A gas distributor and an outlet pipe are located inside the water tank body, and a breather valve and a micro-pressure gauge are located at the top. After fault repair, first close the exhaust pipe / overflow valve and open the exhaust valve on the auxiliary pipe to purge air from top to bottom and test for compliance. Then close the auxiliary pipe, stop the nitrogen supply, open the exhaust pipe to inject ultrapure water, and after the tank is full, close the exhaust pipe and open the overflow valve and nitrogen shut-off valve to quickly stabilize the water quality and shorten the recovery time.

Description

Technical Field

[0001] This utility model relates to the field of water treatment technology in semiconductor manufacturing, and in particular to a highly stable ultrapure water supply system for semiconductor processes. Background Technology

[0002] The semiconductor device manufacturing process has extremely high requirements for the production environment and the purity of raw materials. Ultrapure water, as a key process medium, is widely used in core processes such as wafer cleaning, etching, and photolithography. Its function is to remove impurities such as tiny particles, metal ions, and organic contaminants from the wafer surface, preventing these impurities from affecting the electrical performance, reliability, and yield of semiconductor devices. Therefore, ultrapure water used in semiconductor processes must meet extremely high purity standards, typically requiring a resistivity of not less than 15 MΩ·cm.

[0003] To ensure a stable and reliable supply of ultrapure water, existing semiconductor ultrapure water supply systems generally adopt a "preparation-storage-external supply" process. This involves first preparing qualified ultrapure water through processes such as EDI and reverse osmosis, then storing it in a storage tank and supplying it to production processes as needed. Because ultrapure water, as a high-purity solvent, has an extremely strong ability to dissolve impurities such as carbon dioxide, bacteria, and dust in the air, its quality deteriorates rapidly upon contact with air. Practical experience has shown that ultrapure water with a resistivity of 15 MΩ·cm or higher will have its resistivity drop to 3-4 MΩ·cm after one minute of exposure to air, and further decrease to around 2 MΩ·cm after three minutes, failing to meet the requirements of semiconductor processes.

[0004] To address the issue of secondary contamination during ultrapure water storage, existing technologies commonly employ nitrogen-sealed storage tanks. This method involves filling a sealed tank with inert nitrogen gas at a pressure not exceeding 30 kPa, creating a closed nitrogen barrier layer on the water surface. This prevents ultrapure water from contacting air, thus preventing impurities such as carbon dioxide from dissolving into the water and avoiding water quality degradation.

[0005] However, semiconductor manufacturing has extremely high requirements for the continuous supply of ultrapure water. Although nitrogen-sealed storage tanks can ensure the quality of water stored normally, occasional equipment failures and system shutdowns during production cannot be completely avoided. After an accident is resolved, it usually takes 2-3 days for ultrapure water to stabilize and meet quality standards after being refilled into the nitrogen-sealed tank. During this period, not only can the production water demand not be met, but a large amount of waste ultrapure water is also generated due to substandard water quality, while consuming huge amounts of electricity, resulting in serious energy waste and increased production costs. Utility Model Content

[0006] To solve the above-mentioned technical problems, this utility model provides a highly stable semiconductor process ultrapure water supply system that quickly ensures the quality of ultrapure water re-injected into the nitrogen-sealed water tank is stable and qualified, reduces ultrapure water waste, and at the same time reduces energy waste and lowers production costs.

[0007] This utility model discloses a high-stability semiconductor process ultrapure water supply system, comprising a water tank body. A high-purity nitrogen inlet pipe and an ultrapure water delivery pipe are respectively connected and installed at the top of the water tank body. A pipe connected to the ultrapure water delivery pipe extends into the bottom of the water tank body. An overflow pipe and an ultrapure water discharge pipe are respectively connected and installed at the top and bottom of the circumferential sidewall of the water tank body. Switch valves are connected and installed on both the ultrapure water discharge pipe and the ultrapure water delivery pipe. A shut-off valve and a nitrogen sealing valve are connected and installed on the high-purity nitrogen inlet pipe. The system also includes: An exhaust pipe is installed at the top of the water tank body and is connected to the inside of the water tank body. An exhaust valve is installed in the initial section of the exhaust pipe. The initial section of the overflow pipe is connected to an overflow discharge valve; A liquid seal mechanism for the vent pipe and overflow pipe is placed on one side of the water tank body.

[0008] Furthermore, the liquid sealing mechanism includes a liquid sealing water tank, the top of which is provided with an opening communicating with the chamber, and the exhaust pipe and the overflow pipe are both connected with extension pipes, the extension pipes of the exhaust pipe and the overflow pipe extending into the water surface of the liquid sealing water tank through the opening.

[0009] Furthermore, an auxiliary pipe is connected to the bottom of the circumferential side wall of the water tank body, and an air vent valve is installed on the auxiliary pipe.

[0010] Furthermore, a gas distributor is installed at the top center of the internal chamber of the water tank body. The gas distributor is connected to the output end of the high-purity nitrogen inlet pipe. Several gas outlet pipes are evenly distributed around the gas distributor. The shape of the gas outlet pipes is adapted to the shape of the top of the water tank body. The gas outlet pipes are close to the top of the chamber of the water tank body but do not contact it. Several small gas outlet holes are evenly distributed at the top of the gas outlet pipes.

[0011] Furthermore, each of the aforementioned air outlet pipes has a guide hole connected to its outer end.

[0012] Furthermore, a breather valve and a micro-pressure gauge are connected and installed at the top of the water tank body.

[0013] Furthermore, a water supply pipe is connected to the top of the side wall of the liquid-sealed water tank, and the water supply pipe extends into the liquid-sealed water tank. A float valve is installed on the water supply pipe located inside the liquid-sealed water tank.

[0014] Furthermore, the switching valve, shut-off valve, exhaust valve, and overflow exhaust valve are configured as manual valves or electric valves.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. Significantly shortens the water quality stabilization time after fault recovery: By using the directional venting technology of "closing the exhaust pipe / overflow pipe and opening the auxiliary pipe exhaust valve to introduce nitrogen", combined with the bottom auxiliary pipe venting, the residual air in the water tank is reduced, the dissolved air content is reduced when ultrapure water is injected, and the water quality can be met without a long waiting time, thus meeting the water needs of continuous production. 2. Reduce resource waste and costs: By adopting the logic of "purifying the air first and then injecting ultrapure water", water quality deterioration is avoided from the source, reducing the generation of waste ultrapure water; at the same time, the power consumption of repeatedly treating substandard water is reduced, thus reducing production costs. 3. Improve nitrogen sealing stability: A uniform nitrogen isolation layer is formed by the gas distributor and the air outlet pipe of the guide hole. With real-time monitoring by the micro pressure gauge, precise pressure control by the nitrogen sealing valve, and pressure balancing by the breathing valve, local water quality fluctuations caused by uneven nitrogen sealing are avoided. 4. Simplify operation and improve safety: The auxiliary pipe and exhaust pipe are switched on and off in stages, and the overflow valve opens with a delay, making the fault recovery process clearer and more controllable, reducing operational errors and improving the safety of system operation. 5. Enhanced Liquid Seal Reliability: The liquid seal tank and extension pipe achieve basic sealing, and the water supply pipe is equipped with a float valve to automatically maintain the liquid seal water level and prevent air backflow; at the same time, the fullness of the water tank can be judged by the water flow through the exhaust pipe, enhancing the synergistic protection effect of liquid seal and nitrogen seal. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the installation structure of the gas distributor of this utility model inside the water tank body; Figure 3 This is the utility model Figure 2 A magnified schematic diagram of the structure of part A in the diagram; The following are labeled in the attached diagram: 1. Water tank body; 2. High-purity nitrogen inlet pipe; 3. Ultrapure water delivery pipe; 4. Overflow pipe; 5. Ultrapure water outlet pipe; 6. Switch valve; 7. Shut-off valve; 8. Nitrogen sealing valve; 9. Exhaust pipe; 10. Overflow discharge valve; 11. Liquid-sealed water tank; 12. Extension pipe; 13. Auxiliary pipe; 14. Gas distributor; 15. Gas outlet pipe; 16. Flow guide hole; 17. Breathing valve; 18. Micro pressure gauge; 19. Water supply pipe; 20. Float valve. Detailed Implementation

[0017] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0018] like Figures 1 to 3As shown, this utility model discloses a high-stability semiconductor process ultrapure water supply system, comprising a water tank body 1. A high-purity nitrogen inlet pipe 2 and an ultrapure water delivery pipe 3 are respectively connected and installed at the top of the water tank body 1. A pipe connected to the ultrapure water delivery pipe 3 extends into the bottom of the water tank body 1. An overflow pipe 4 and an ultrapure water discharge pipe 5 are respectively connected and installed at the top and bottom of the circumferential sidewall of the water tank body 1. Switch valves 6 are connected and installed on both the ultrapure water discharge pipe 5 and the ultrapure water delivery pipe 3. A shut-off valve 7 and a nitrogen sealing valve 8 are connected and installed on the high-purity nitrogen inlet pipe 2. The system also includes: Exhaust pipe 9 is installed at the top of water tank body 1 and is connected to the inside of water tank body 1. An exhaust valve is installed in the initial section of exhaust pipe 9. The initial section of the overflow pipe 4 is connected to an overflow discharge valve 10; A liquid seal mechanism for the exhaust pipe 9 and the overflow pipe 4 is placed on one side of the water tank body 1. In this embodiment, Exhaust pipe 9: Installed at the top of the water tank body 1, it is opened during the ultrapure water filling stage after the fault is repaired to discharge the small amount of residual gas squeezed out by the rise in water level in the water tank; it is closed after the ultrapure water is full, and works with nitrogen sealing to prevent air from entering. Exhaust valve: Controls the opening and closing of the exhaust pipe in 9 stages. It is closed during the initial stage of fault repair to prevent nitrogen from escaping from the top; it is opened during the ultrapure water injection stage to ensure gas discharge; and it is closed after the tank is full to achieve a seal, precisely matching the needs of different operation stages. Overflow discharge valve 10: Installed in the initial section of overflow pipe 4, it is closed during the ultrapure water filling stage after fault repair to prevent accidental water overflow; it is opened after the ultrapure water tank is full and the vent pipe 9 is closed to ensure pressure balance in the water tank and avoid damage to the equipment when there is too much ultrapure water. Liquid seal mechanism: placed on one side of the water tank body 1, it prevents air from flowing back through the exhaust pipe 9 / overflow pipe 4; on the other hand, when ultrapure water is injected, the ultrapure water flows into the liquid seal water tank 11 through the exhaust pipe 9, which can be used as a basis for judging that the water tank is full, while maintaining the stability of the liquid seal effect.

[0019] As a preferred embodiment of the above, the liquid sealing mechanism includes a liquid sealing water tank 11, the top of the liquid sealing water tank 11 is provided with an opening communicating with the chamber, and the exhaust pipe 9 and the overflow pipe 4 are both connected to an extension pipe 12, and the extension pipes 12 of the exhaust pipe 9 and the overflow pipe 4 extend into the water surface of the liquid sealing water tank 11 through the opening. In this embodiment, Liquid-sealed water tank 11: Provides liquid-sealed space, and seals the vent pipe 9 / overflow pipe 4 extension pipe 12 through water; during the ultrapure water injection stage, it can receive the water flowing in from the vent pipe 9, and visually displays whether the water tank is full; the water supply pipe 19 works with the float valve 20 to maintain the water level and ensure that the liquid seal is continuously effective; Extension pipe 12: It is connected to the exhaust pipe 9 and the overflow pipe 4 respectively and extends into the liquid-sealed water tank 11 below the water surface. During the fault repair exhaust stage, it prevents air from entering from the exhaust pipe 9 / overflow pipe 4. During the ultrapure water injection stage, the exhaust gas is filtered through the water (reducing impurities). When the ultrapure water tank is full, the water can flow into the liquid-sealed water tank 11 along the extension pipe 12 to realize full tank monitoring.

[0020] As a preferred embodiment of the above, an auxiliary pipe 13 is connected to the bottom of the circumferential side wall of the water tank body 1, and an exhaust valve is installed on the auxiliary pipe 13. In this embodiment, Auxiliary pipe 13: Connected to the bottom of the circumferential side wall of the water tank body 1. After the fault is repaired, it serves as the core exhaust channel. Utilizing the characteristic of nitrogen compressing air from top to bottom, air is discharged from the bottom auxiliary pipe 13 to avoid air remaining at the bottom of the water tank. Exhaust valve (on auxiliary pipe 13): Opens during the initial repair of the fault to provide a channel for air to be discharged; closes after confirming that the air has been discharged by observing the bubbles in soapy water or detecting the nitrogen concentration, to prevent water from leaking from auxiliary pipe 13 during subsequent injection of ultrapure water, and to avoid nitrogen loss.

[0021] As a preferred embodiment of the above embodiment, a gas distributor 14 is installed at the top center of the internal cavity of the water tank body 1. The gas distributor 14 is connected to the output end of the high-purity nitrogen inlet pipe 2. A plurality of gas outlet pipes 15 are evenly distributed around the gas distributor 14. The shape of the gas outlet pipes 15 is adapted to the shape of the top of the water tank body 1. The gas outlet pipes 15 are close to the top of the cavity of the water tank body 1 but do not contact it. A plurality of small gas outlet holes are evenly distributed at the top of the gas outlet pipes 15. In this embodiment, Gas distributor 14: Installed at the top center of the internal chamber of the water tank body 1, and connected to the output end of the high-purity nitrogen inlet pipe 2. During the fault repair and exhaust stage, it evenly distributes high-purity nitrogen to each outlet pipe 15 to ensure that nitrogen diffuses evenly in the water tank and achieves stable compression of air from top to bottom. Vent pipe 15: It is circumferentially and uniformly connected to the gas distributor 14. Its shape is adapted to the top of the water tank body 1 and it is close to the top but does not contact it. During the fault repair and exhaust stage, it delivers the uniformly distributed nitrogen to the top area of ​​the water tank. Utilizing the low density characteristics of nitrogen, it pushes the air to flow towards the bottom auxiliary pipe 13 to improve exhaust efficiency. During routine nitrogen sealing, it can help form a uniform nitrogen isolation layer.

[0022] As a preferred embodiment of the above, each of the outer ends of the plurality of air outlet pipes 15 is provided with a guide hole 16. In this embodiment, The guide hole 16 is connected to the outer end of the vent pipe 15. During the venting stage of fault repair, it guides the nitrogen released from the vent pipe 15 to diffuse towards the side wall of the water tank, avoiding nitrogen concentration in the middle and causing air residue. It further optimizes the coverage of nitrogen in the water tank and ensures that the air is fully squeezed to the bottom auxiliary pipe 13. On the other hand, when the water tank body 1 is filled with ultrapure water and flows out of the vent pipe 9, the vent pipe 15 is immersed in ultrapure water. There will be ultrapure water accumulation inside, which will affect the nitrogen filling process. After the water level drops, the ultrapure water in the vent pipe 15 can be discharged through the guide hole 16, ensuring that the vent pipe 15 can smoothly pass nitrogen into the water tank body 1.

[0023] As a preferred embodiment of the above embodiment, a breather valve 17 and a micro pressure gauge 18 are connected and installed at the top of the water tank body 1; In this embodiment, Breathing valve 17: Installed at the top of the water tank body 1, during the fault repair and venting stage (when the auxiliary pipe 13 is open), it can balance the pressure inside and outside the water tank and avoid a sudden pressure rise due to nitrogen injection; during normal operation, it will automatically open when the pressure inside the water tank is abnormal (too high / too low) to ensure the safety of the water tank and prevent pressure fluctuations from affecting the water quality. Micro pressure gauge 18: Installed on the top of the water tank body 1, during the fault repair and venting stage, it monitors the nitrogen pressure in the water tank in real time, so that the operator can control the amount of nitrogen introduced and avoid damage to the equipment due to excessive pressure or incomplete venting due to excessive pressure; during daily nitrogen sealing, it maintains the pressure stable within 30Kpa to ensure the nitrogen sealing effect.

[0024] As a preferred embodiment of the above embodiment, a water supply pipe 19 is connected to the top of the side wall of the liquid-sealed water tank 11, and the water supply pipe 19 extends into the liquid-sealed water tank 11. A float valve 20 is installed on the water supply pipe 19 located in the liquid-sealed water tank 11. In this embodiment, Water supply pipe 19: Connected to the top of the side wall of the liquid seal water tank 11 and extending into the liquid seal water tank 11. During the ultrapure water filling stage, when the water level of the liquid seal water tank 11 is abnormal due to receiving ultrapure water flowing in from the exhaust pipe 9 or when daily evaporation occurs, water is replenished to the liquid seal water tank 11 to maintain the liquid seal water level. Float valve 20: Installed on the water supply pipe 19 inside the liquid-sealed water tank 11, it automatically controls the opening and closing of the water supply pipe 19 according to the water level of the liquid-sealed water tank 11. It opens to supply water when the water level is too low and closes when the water level reaches the standard, ensuring that the exhaust pipe 9 / overflow pipe 4 extension pipe 12 is always submerged in water, avoiding backflow of air due to liquid seal failure.

[0025] As a preferred embodiment of the above, the switching valve 6, the shut-off valve 7, the exhaust valve, and the overflow exhaust valve are configured as manual valves or electric valves. In this embodiment, Based on actual production costs and usage requirements, choose between manual or electric valves. The manual / electric option adapts to different automation needs and improves operational flexibility.

[0026] The working principle of this utility model is as follows: The core workflow after the system fault is repaired is as follows: First, close the exhaust valve and overflow discharge valve 10 on the exhaust pipe 9, open the exhaust valve on the auxiliary pipe 13 at the bottom of the water tank body 1, and at the same time open the shut-off valve 7 of the high-purity nitrogen inlet pipe 2 to introduce high-purity nitrogen into the water tank body 1; taking advantage of the fact that nitrogen is less dense than air, the nitrogen diffuses evenly to the top of the water tank under the action of the gas distributor 14 and the outlet pipe 15 (including the guide hole 16), and squeezes the air in the water tank from top to bottom to flow to the bottom, and finally the air is discharged through the auxiliary pipe 13; after confirming that the exhaust meets the standard by observing the bubbles in soapy water (no air bubbles) or by using a nitrogen concentration detector, close the exhaust valve on the auxiliary pipe 13, and at the same time close the shut-off valve 7 of the high-purity nitrogen inlet pipe 2 to stop the nitrogen supply. Then, open the vent valve on the vent pipe 9, keep the overflow discharge valve 10 closed, open the switch valve 6 on the ultrapure water delivery pipe 3, and inject ultrapure water into the water tank body 1. At this time, the amount of residual air in the water tank body 1 is extremely small, so the amount of ultrapure water entering the water tank body 1 is extremely small. As the water level rises, a small amount of residual gas in the water tank is discharged through the vent pipe 9. When the ultrapure water flows into the liquid-sealed water tank 11 along the extension pipe 12 of the vent pipe 9 (judging that the water tank is full), close the vent valve on the vent pipe 9, and at the same time open the overflow discharge valve 10 and the shut-off valve 7 of the high-purity nitrogen inlet pipe 2, and work with the nitrogen sealing valve 8 to maintain the nitrogen pressure in the water tank is stable. Finally, the water quality of the ultrapure water is tested. The time from the injection of ultrapure water into the water tank body 1 to the water quality stabilization is greatly reduced. During daily operation, the micro pressure gauge 18 monitors the pressure, the breather valve 17 balances the pressure, the liquid-sealed water tank 11 maintains the water level through the water supply pipe 19 and the float valve 20, and the ultrapure water discharge pipe 5 supplies liquid to the outside as needed. The overall process, through the coordinated efforts of "directional venting, precise detection, phased liquid injection, and nitrogen sealing," significantly shortens the time for ultrapure water quality to recover after fault repair, ensures water quality stability, and reduces resource waste.

[0027] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A high-stability semiconductor process ultrapure water supply system, comprising a water tank body (1), wherein a high-purity nitrogen inlet pipe (2) and an ultrapure water delivery pipe (3) are respectively connected and installed at the top of the water tank body (1), and the pipe connected to the ultrapure water delivery pipe (3) inside the water tank body (1) extends to the bottom of the water tank body (1), wherein an overflow pipe (4) and an ultrapure water discharge pipe (5) are respectively connected and installed at the top and bottom of the circumferential sidewall of the water tank body (1), and both the ultrapure water discharge pipe (5) and the ultrapure water delivery pipe (3) are connected and installed with a switch valve (6), and a shut-off valve (7) and a nitrogen sealing valve (8) are connected and installed on the high-purity nitrogen inlet pipe (2), characterized in that, Also includes: The exhaust pipe (9) is installed at the top of the water tank body (1) and is connected to the inside of the water tank body (1). An exhaust valve is installed in the initial section of the exhaust pipe (9). The initial section of the overflow pipe (4) is connected to an overflow discharge valve (10). A liquid seal mechanism for the vent pipe (9) and overflow pipe (4) is placed on one side of the water tank body (1).

2. The high-stability semiconductor process ultrapure water supply system as described in claim 1, characterized in that, The liquid sealing mechanism includes a liquid sealing water tank (11), the top of which is provided with an opening communicating with the chamber. The exhaust pipe (9) and the overflow pipe (4) are both connected to an extension pipe (12). The extension pipes (12) of the exhaust pipe (9) and the overflow pipe (4) extend into the water below the surface of the liquid sealing water tank (11) through the opening.

3. The high-stability semiconductor process ultrapure water supply system as described in claim 1, characterized in that, An auxiliary pipe (13) is connected to the bottom of the circumferential side wall of the water tank body (1), and an exhaust valve is installed on the auxiliary pipe (13).

4. The high-stability semiconductor process ultrapure water supply system as described in claim 3, characterized in that, A gas distributor (14) is installed at the top center of the internal cavity of the water tank body (1). The gas distributor (14) is connected to the output end of the high-purity nitrogen inlet pipe (2). The gas distributor (14) is circumferentially connected with several gas outlet pipes (15). The shape of the gas outlet pipes (15) is adapted to the shape of the top of the water tank body (1). The gas outlet pipes (15) are close to the top of the cavity of the water tank body (1) but do not contact it. Several small gas outlet holes are evenly distributed at the top of the gas outlet pipes (15).

5. The high-stability semiconductor process ultrapure water supply system as described in claim 4, characterized in that, Each of the aforementioned air outlet pipes (15) has a guide hole (16) connected to its outer end.

6. The high-stability semiconductor process ultrapure water supply system as described in claim 1, characterized in that, The top of the water tank body (1) is connected to a breather valve (17) and a micro pressure gauge (18).

7. The high-stability semiconductor process ultrapure water supply system as described in claim 2, characterized in that, A water supply pipe (19) is connected to the top of the side wall of the liquid-sealed water tank (11), and the water supply pipe (19) extends into the liquid-sealed water tank (11). A float valve (20) is installed on the water supply pipe (19) located in the liquid-sealed water tank (11).

8. A high-stability semiconductor process ultrapure water supply system as described in any one of claims 1-7, characterized in that, The switching valve (6), shut-off valve (7), exhaust valve, and overflow exhaust valve are configured as manual valves or electric valves.

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