A water tank assembly and a lithographic machine immersion liquid supply system

Abstract

The present application relates to the technical fields of immersion liquid supply of photoetching machine, and discloses a water tank assembly and an immersion liquid supply system of photoetching machine, the water tank assembly comprises: a first water tank and a second water tank, the second water tank is located in the first water tank, the top of the first water tank is provided with an overflow port, the top of the second water tank is provided with an immersion liquid downflow port, and the overflow port of the first water tank is higher than the immersion liquid downflow port of the second water tank; the bottom of the first water tank is communicated with an immersion liquid inlet, and the bottom of the second water tank is communicated with an immersion liquid outlet. The immersion liquid entering the first water tank rises and is divided into two water flows, one of the immersion liquid starts to downflow at the immersion liquid downflow port K1, enters the second water tank, and the other of the immersion liquid overflows to the outside of the first water tank through the overflow port. During the immersion liquid return outflow process, counterflow heat exchange and temperature compensation are carried out, the temperature control is accurate and stable, the generation of fine bubbles is reduced, the dissolution of oxygen and other gases is reduced, the secondary pollution of dissolved oxygen, bubbles, bacteria, particles, organic matter and the like is reduced, and the pressure, temperature and flow fluctuation are reduced.

Description

Technical Field

[0001] This invention relates to the field of lithography machine immersion solution supply technology, and particularly to a water tank assembly and a lithography machine immersion solution supply system. Background Technology

[0002] With the development of the electronics and semiconductor industries, ultrapure water plays an increasingly crucial role in the chip manufacturing process. Consequently, the quality requirements for ultrapure water are becoming increasingly stringent.

[0003] Photolithography is a crucial technology in integrated circuit manufacturing, utilizing the photochemical reaction characteristics of photosensitive emulsion to copy designed circuit patterns onto a silicon wafer. Immersion lithography, also known as wet lithography, is an improvement on traditional dry lithography. It involves filling the space between the lower surface of the final projection lens and the photoresist on the silicon wafer with an immersion liquid that increases the refractive index of the entire optical path. High-purity water is typically used as the immersion liquid. The high-purity water flow field replaces the air in the center of traditional dry lithography. Because the refractive index of ultrapure water (1.44) is greater than that of air (1.00), the numerical aperture of the lens group increases, resulting in smaller feature linewidths. In integrated circuit manufacturing, as chip feature sizes continue to shrink, the requirements for the quality of ultrapure water used in the immersion lithography process are becoming increasingly stringent. The presence of ions, dissolved oxygen, TOC, particulate matter, and bubbles in the immersion liquid reduces the yield of integrated circuits. Introducing a liquid into the system is the essential characteristic of wet lithography. During the exposure process, the liquid filling the space between the projection lens and the silicon wafer becomes part of the optical path, effectively functioning as the projection lens; therefore, it requires extremely high purity. The International Technology Roadmap for Semiconductors (ITRS) updated its ultrapure water quality requirements in its 2016 report, indicating that current ultrapure water quality standards are essentially at their limit. Even with such extremely high purity, even minor contamination can render the ultrapure water unsuitable for wet lithography.

[0004] According to the requirements of the 2012 edition of the International Technology Roadmap for Semiconductors (ITRS), the chapter on "Improving Yield" includes two sub-chapters: "Wafer Environment and Contamination Control" (WECC) and "Qualification, Detection, and Analysis" (CIA). Related content includes yield testing methods and data correlation to determine the correlation between defects caused by the wafer manufacturing environment and throughput. This requires us to determine the cleanliness control limits for gases, chemicals, air, precursors, and substrate surfaces, including ultrapure water. With the continuous improvement of lithography technology and new manufacturing technologies, the corresponding effect of contamination control in WECC has become increasingly important. Therefore, current next-generation lithography technologies place more emphasis on extreme ultraviolet (EUV) technology and water contamination control.

[0005] In ultrapure water for very large-scale integrated circuits (VLSI), priority water quality indicators include resistivity, particulate matter, TOC (total organic carbon), bacteria, soluble silicon, heavy metals, and DO (dissolved oxygen), as these significantly impact semiconductor device production. During integrated circuit chip manufacturing, the higher the ion content of the medium in contact with the silicon wafer, the greater the impact on product yield. The ion concentration in ultrapure water can be characterized by resistivity. Particulate count is also an indicator of ultrapure water purity. Impurities or particulate matter in the cleaning water used in the photolithography process of integrated circuits can lead to uneven gate oxide film thickness and product pattern defects. Excessive particle count in the immersion liquid can also cause exposure defects. Trace organic matter in ultrapure water affects the insulation withstand voltage performance of the gate oxide film. The impact of bacteria in ultrapure water is similar to that of TOC and particulate matter, primarily because bacterial proliferation within the system makes them a source of organic matter and particulate matter. Dissolved oxygen in ultrapure water accelerates the oxidation reaction on the silicon wafer surface, leading to premature oxide film formation. The impact of air bubbles is mainly due to the difference in refractive index between them and ultrapure water. The refractive index of bubbles (1.00) and that of ultrapure water (1.44) differ greatly. Bubbles in the ultrapure water feed liquid of the lithography machine can easily cause exposure defects in the lithography machine, which has a great impact on the chip manufacturing yield.

[0006] In immersion lithography, ultrapure water is used to form the immersion liquid flow field. This ultrapure water, as the immersion liquid, needs to be supplied by the lithography machine's immersion liquid supply system (hereinafter referred to as the immersion supply system). The immersion liquid flow field has extremely stringent requirements for pressure and temperature. Changes in the immersion liquid flow field pressure will affect the refractive index; a pressure change of 1000 Pa will affect the lithography accuracy by approximately 2 nm. Changes in the immersion liquid flow field temperature will also affect the refractive index; a temperature change of 0.01 °C will affect the lithography accuracy by approximately 3 nm. To ensure a continuous replenishment of the ultrapure water within the immersion liquid flow field and to maximize the uniformity of the state throughout the flow field, the flow rate of the immersion liquid should also remain highly stable. Therefore, the immersion supply system needs to precisely control the pressure, temperature, and flow rate of the immersion liquid, keeping their fluctuations within a very small range to maintain a high degree of stability. Summary of the Invention

[0007] This invention discloses a water tank assembly and a lithography machine immersion solution supply system for precisely controlling the pressure, temperature and flow rate of the immersion solution.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] In a first aspect, a water tank assembly is provided, comprising: a first water tank and a second water tank, the second water tank being located inside the first water tank, the top of the first water tank having an overflow port, the top of the second water tank having an immersion liquid discharge port, and the overflow port of the first water tank being higher than the immersion liquid discharge port of the second water tank; the bottom of the first water tank being connected to an immersion liquid inlet, and the bottom of the second water tank being connected to an immersion liquid outlet.

[0010] The immersion liquid entering the first water tank rises and splits into two streams. One stream descends at the immersion liquid downflow inlet K1 and enters the second water tank, while the other overflows out of the first water tank through the overflow outlet. These two streams, rising and falling, perform counter-current heat exchange, achieving temperature compensation for the immersion liquid in the second water tank, resulting in more precise and stable temperature control. The immersion liquid enters from the bottom of the first water tank, reducing disturbance to the overflow surface, minimizing the generation of fine bubbles, and reducing the dissolution of gases such as oxygen and carbon dioxide. This reduces secondary pollution from dissolved oxygen, bubbles, bacteria, particles, and organic matter, and also lowers fluctuations in pressure, temperature, and flow rate.

[0011] Optionally, along the direction away from the bottom of the first water tank, the outer diameter of the end of the second water tank having the immersion outlet gradually decreases to form a guide slope.

[0012] Optionally, the height difference between the overflow port of the first water tank and the immersion outlet of the second water tank is between 20 mm and 60 mm.

[0013] Optionally, the cross-sectional area of ​​the first water tank is 3 to 6 times that of the cross-sectional area of ​​the second water tank.

[0014] Optionally, the second water tank is coaxially arranged with the first water tank.

[0015] Optionally, the water tank assembly further includes an inlet water tank located at the bottom of the first water tank, the inlet water tank being connected to the first water tank via the bottom of the first water tank; the immersion inlet is located at the bottom of the inlet water tank.

[0016] Optionally, the bottom of the second water tank is connected to an outlet pipe, which extends longitudinally through the inlet water tank and from the bottom of the inlet water tank to the outside of the inlet water tank. The end of the outlet pipe away from the second water tank is connected to the immersion outlet. The longitudinal direction refers to the arrangement direction of the first water tank and the inlet water tank.

[0017] Optionally, the bottom of the liquid inlet tank is provided with a small immersion return pipe.

[0018] Optionally, the flow rate Q of the immersion small reflux pipe 小回 The flow rate Q at the immersion liquid inlet 进 Between 1% and 10%.

[0019] Optionally, the water tank assembly further includes a third water tank, with the first water tank located inside the third water tank, and the side wall of the third water tank is provided with a large immersion return pipe.

[0020] Optionally, the third water tank is filled with nitrogen.

[0021] Optionally, a partition plate is provided between the side wall of the inlet tank and the side wall of the third tank to isolate the inlet tank from the first tank, the second tank and the third tank respectively; the partition plate is provided with a plurality of immersion flow holes distributed along a ring, and the plurality of immersion flow holes connect the first tank and the inlet tank.

[0022] Optionally, the flow rate Q of the immersion liquid inlet 进 The flow rate Q of the immersion liquid outlet 出 Satisfy: Q 进 3Q 出 .

[0023] Secondly, a lithography machine immersion solution supply system is provided, the lithography machine immersion solution supply system comprising: a lithography machine near-end ultrapure water deep purification device, an immersion head, and a water tank assembly as described in any of the above technical solutions, wherein the outlet of the lithography machine near-end ultrapure water deep purification device is connected to the immersion solution inlet of the water tank assembly, and the immersion solution outlet of the water tank assembly is connected to the immersion head.

[0024] The advantages of the lithography machine immersion solution supply system and the water tank assembly compared to the prior art are the same, and will not be repeated here. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the water tank assembly provided in the embodiments of this application;

[0026] Figure 2 This is a schematic diagram of the lithography machine immersion solution supply system provided in an embodiment of this application. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] refer to Figure 1The water tank assembly provided in this application includes: a first water tank 312 and a second water tank 311. The second water tank 311 is located inside the first water tank 312. The top of the first water tank 312 has an overflow port K3, and the top of the second water tank 311 has an immersion liquid downflow port K1. The overflow port K3 of the first water tank 312 is higher than the immersion liquid downflow port K1 of the second water tank 311. The bottom of the first water tank 312 is connected to the immersion liquid inlet 36, specifically, it is connected to the space between the side wall of the first water tank 312 and the side wall of the second water tank 311. The bottom of the second water tank 311 is connected to the immersion liquid outlet 37. Specifically, an immersion liquid inlet pipe 361 can be used to deliver ultrapure water immersion liquid to the immersion liquid inlet 36.

[0029] The pressure within the immersion liquid flow field of the lithography machine is micro-pressure, typically in the kilopascal range. Therefore, by utilizing the first water tank 312 and the second water tank 311, located at higher positions, a stable static pressure is provided to the immersion liquid flow field through the immersion liquid outlet 37 at a lower position via gravity outflow. A suitable elevation difference H is set to ensure that the water tank assembly 3 meets the pressure requirements of the immersion liquid flow field. Specifically, the elevation difference H refers to the height difference between the overflow liquid surface P and the immersion head 6.

[0030] The ultrapure water immersion solution entering through the immersion solution inlet 36 enters the first water tank 312 from the bottom, specifically into the space between the side walls of the first water tank 312 and the second water tank 311. The immersion solution entering the first water tank 312 continues to rise and gradually splits into two streams: the liquid level in the first water tank 312 gradually rises until it covers the immersion solution outlet K1 of the second water tank 311, where it begins to descend, entering the second water tank 311 and flowing through the bottom of the second water tank 311 to the immersion solution outlet 37; the immersion solution in the first water tank 312 continues to rise to the overflow outlet K3, where it forms an overflow liquid surface P and overflows out of the first water tank 312.

[0031] The two water streams rise and fall, and are separated by the side wall of the second water tank 311. Counter-current heat exchange can be carried out through the side wall of the second water tank 311 to achieve temperature compensation of the immersion liquid in the second water tank 311, reduce the temperature difference between the immersion liquid inlet 36 and the immersion liquid outlet 37, and make the overall temperature control more precise and stable.

[0032] The immersion liquid enters from the bottom of the first water tank 312. During the upward flow process, the dynamic pressure of the immersion liquid is gradually eliminated. Compared with the top-entry water tank, it can reduce the disturbance to the overflow surface of the immersion liquid, reduce the production of fine bubbles, reduce secondary pollution, and reduce pressure, temperature and flow fluctuations.

[0033] Specifically, firstly, compared to traditional water tanks, the overflow port K3 of the first water tank 312 is higher than the immersion liquid drain port K1 of the second water tank 311. The immersion liquid in the first water tank 312 provides better shielding against water flow interference to the top and sides of the second water tank 311, reducing the risk of pressure, temperature, and flow fluctuations. Secondly, compared to traditional water tanks, the immersion liquid drain port K1 of the second water tank 311 is kept at a distance from the immersion liquid overflow surface P. The immersion liquid drain port K1 at the water intake position of the second water tank 311 is far away from the gas-liquid two-phase interface at the immersion liquid overflow surface P, greatly reducing the risk of fine air bubbles mixed in with the immersion liquid entering the second water tank 311, and reducing the risk of pollution from dissolved gases such as oxygen and carbon dioxide. Third, in the relevant water tanks where the immersion liquid enters from the bottom, there is no isolation between the inflow and outflow of the immersion liquid from the bottom. The outflow of the immersion liquid from the bottom is easily disturbed by the dynamic pressure of the inflow of the immersion liquid from the bottom. The two water flows from the first water tank 312 and the second water tank 311 are separated by the side wall of the second water tank 311, reducing disturbance. In addition, the immersion liquid from the first water tank 312 needs to undergo one upflow and one downflow before entering the second water tank 311. During this backflow process, the effect of particle entrainment in the immersion liquid is reduced, and the risk of particles flowing out with the immersion liquid is greatly reduced.

[0034] In one specific embodiment, along the direction away from the bottom of the first water tank 312, the outer diameter of the end of the second water tank 311 with the immersion outlet K1 gradually decreases to form a guide slope M. After the water in the first water tank 312 flows upward, some of the particles will be deposited on the inclined guide slope M and slide down from the guide slope M to the bottom of the first water tank 312, reducing the situation where the immersion liquid carries particles out of the tank.

[0035] In one specific embodiment, the height difference between the overflow port K3 of the first water tank 312 and the immersion liquid drain port K1 of the second water tank 311 is between 20mm and 60mm, for example, it can be 20mm, 30mm, 40mm, 50mm, and 60mm. If the height difference is too large, it will waste the limited height space; if the height difference is too small, it will cause the immersion liquid drain port K1 of the second water tank 311 to be too close to the immersion liquid overflow surface P. The second water tank 311 draws water through the immersion liquid drain port K1 close to the gas-liquid two-phase interface, which still poses a risk of fine air bubbles being mixed into the immersion liquid entering the second water tank 311.

[0036] In one specific embodiment, the cross-sectional area of ​​the first water tank 312 is 3 to 6 times that of the cross-sectional area of ​​the second water tank 311. For example, it can be 3, 4, 5, or 6 times, etc. If the multiple is too large, the downflow effect of the second water tank 311 is limited, and the heat exchange area of ​​the sidewall is small. If the multiple is too small, the space between the first water tank 312 and the second water tank 311 will be too small, which is not conducive to upflow and makes it difficult to achieve balance with the downflow in the second water tank 311.

[0037] In one specific embodiment, the second water tank 311 is coaxially arranged with the first water tank 312, so that the flow velocity of the liquid flowing down to the immersion outlet K1 around the second water tank 311 is uniform, providing a more stable flow rate and reducing disturbance.

[0038] In one specific embodiment, the water tank assembly further includes an inlet water tank 321 located at the bottom of the first water tank 312, which is connected to the first water tank 312 via the bottom of the first water tank 312; the immersion liquid inlet 36 is located at the bottom of the inlet water tank 321. The immersion liquid entering through the immersion liquid inlet 36 flows upward within the inlet water tank 321 and enters the first water tank 312 via the bottom of the first water tank 312, further reducing the dynamic pressure of the immersion liquid. After the immersion liquid flows into the inlet water tank 321, due to the increased space, the flow rate of the immersion liquid slows down rapidly, and the flow state quickly enters a more stable state. The inlet water tank 321 is sealed at the bottom by a bottom partition 35.

[0039] In one specific embodiment, the bottom of the second water tank 311 is connected to an outlet pipe 322. The outlet pipe 322 extends longitudinally through the inlet water tank 321 and extends from the bottom of the inlet water tank 321 to the outside of the inlet water tank 321. The end of the outlet pipe 322 away from the second water tank 311 is connected to the immersion outlet 37. The longitudinal direction indicates the arrangement direction of the first water tank 312 and the inlet water tank 321.

[0040] The leaching liquid exiting from the second water tank 311 flows downwards in the outlet pipe 322 in a descending manner, facilitating thorough counter-current heat exchange. This improves heat exchange efficiency and temperature compensation, reduces temperature differences, and further enhances the accuracy and stability of temperature control. The two water streams are completely separated by the wall of the outlet pipe 322, reducing the disturbance of the leaching liquid in the outlet pipe 322 caused by the dynamic pressure of the leaching liquid in the inlet water tank 321. The space of the inlet water tank 321 is much larger than that of the outlet pipe 322, giving it a strong energy and temperature buffering capacity, which better stabilizes and controls the temperature of the outflowing leaching liquid.

[0041] In one specific embodiment, the bottom of the inlet tank 321 is equipped with a small immersion return pipe 39. Firstly, this ensures that the bottom of the tank is always in a flowing water state, reducing the risk of bacterial growth and significantly lowering the risk of excessive levels of bacteria, particles (specifically biological particles), and TOC. Secondly, the small immersion return pipe 39 allows particles deposited at the bottom of the inlet tank 321 to be carried away by the return water flow, preventing sediment from being stirred up by water flow disturbances and subsequently entering the immersion flow field with the immersion liquid, thus avoiding any adverse impact on photolithography yield.

[0042] In one specific embodiment, the flow rate Q of the immersion small reflux pipe 39 is... 小回 The flow rate Q at the immersion liquid inlet is 36%.进 It can be between 1% and 10%, specifically 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%, etc. If the flow rate Q... 小回 Compared to Q 进 If the flow rate is too high, it will cause the liquid to flow back too quickly through the small return pipe 39, resulting in an excessively high flow velocity in the inlet tank 321. This is detrimental to water flow stability and water retention in the inlet tank 321. If the flow rate Q... 小回 Compared to Q 进 If the water is too small, it will be difficult to form effective flowing water to remove the deposited particles.

[0043] In one specific embodiment, the water tank assembly further includes a third water tank 313, with the first water tank 312 located inside the third water tank 313. A large reflux pipe 38 for the immersion liquid is provided on the side wall of the third water tank 313. Immersion liquid overflowing from the first water tank 312 enters the third water tank 313, which concentrates the overflowing liquid. The overflowing liquid falls onto the reflux liquid surface Q of the third water tank 313 and is then returned through the large reflux pipe 38, preventing impurities from depositing in the third water tank 313 or affecting the purity of the immersion liquid in the first water tank 312 after overflow. The third water tank 313 is sealed by a top partition 33.

[0044] In one specific embodiment, the third water tank 313 is filled with nitrogen gas to prevent the gas-liquid two-phase interface of the overflow liquid surface P from being easily contaminated by impurities such as particles in the air. At the same time, it can keep the nitrogen gas at a low pressure to prevent the nitrogen gas pressure from disturbing the overflow liquid surface P.

[0045] In one specific embodiment, a partition plate 34 is provided between the side wall of the inlet tank 321 and the side wall of the third tank 313 to separate the inlet tank 321 from the first tank 312, the second tank 311, and the third tank 313, respectively. The partition plate 34 provides support for the first tank 312, the second tank 311, and the third tank 313. The partition plate 34 has a plurality of immersion flow risers K2 distributed along a ring, which connect the first tank 312 and the inlet tank 321. The immersion liquid in the inlet tank 321 enters the first tank 312 through the immersion flow risers K2 by means of upward flow. The plurality of immersion flow risers K2 can be evenly distributed to ensure uniform water flow velocity throughout the first tank 312.

[0046] In one specific embodiment, the flow rate Q of the immersion liquid inlet 36 进 The flow rate Q of the immersion liquid outlet 37 出 Satisfy: Q 进 3Q 出 Theoretically, Q 进 =Q 出 +Q 大回 +Q 小回, making Q 进 3Q 出 This makes it easier to stabilize the outflow state of the leaching liquid.

[0047] Based on the same inventive concept, this application also provides a lithography machine immersion solution supply system, see reference. Figure 2 The lithography machine immersion solution supply system includes: a near-end ultrapure water deep purification device 1, an immersion head 6, and a water tank assembly 3 provided in the above embodiment. The outlet of the near-end ultrapure water deep purification device 1 is connected to the immersion solution inlet 36 of the water tank assembly 3, and the immersion solution outlet 37 of the water tank assembly 3 is connected to the immersion head 6. Its beneficial effects can be referred to the water tank assembly 3 described above.

[0048] The lithography machine near-end ultrapure water deep purification device 1 receives ultrapure water from the source and deeply removes dissolved oxygen, bubbles, bacteria, particles, and TOC from the ultrapure water. The lithography machine near-end ultrapure water deep purification device 1 can adopt the lithography machine near-end ultrapure water deep purification device described in patent application number 202310271849.1, entitled "A Lithography Machine Near-End Ultrapure Water Deep Purification Device and Lithography Machine Water Supply System," effectively dealing with accidental backflow or reverse diffusion of contaminants (dissolved oxygen, bubbles, bacteria, particles, organic matter), improving the reliability of the immersion water quality. The lithography machine near-end ultrapure water deep purification device 1 can also employ other purification devices that can achieve the same function.

[0049] Subsequently, the deeply treated ultrapure water extract enters the first heat exchange unit 2 for heat exchange, allowing for precise and stable temperature control of the ultrapure water extract. The first heat exchange unit 2 can employ a shell-and-tube heat exchange method.

[0050] After flowing out of the first heat exchange unit 2, the relatively stable ultrapure water immersion solution enters the water tank assembly 3, forming an immersion solution with micro-pressure.

[0051] Subsequently, the immersion liquid enters the second heat exchange unit 4 for further heat exchange, precisely controlling the immersion liquid temperature. The second heat exchange unit 4 can adopt a shell-and-tube heat exchange method. Then, the flow rate is controlled by the flow control unit 5, and the liquid enters the immersion liquid flow field through the immersion head 6.

[0052] Compared to the traditional immersion lithography machine immersion solution supply system, the solution provided in this application embodiment has a shorter process, reduced complexity, and lower cost.

[0053] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A water tank assembly, characterized in that, It includes: a first water tank and a second water tank, the second water tank being located inside the first water tank, the top of the first water tank having an overflow port, the top of the second water tank having an immersion drain port, and the overflow port of the first water tank being higher than the immersion drain port of the second water tank. The bottom of the first water tank is connected to the immersion liquid inlet, and the bottom of the second water tank is connected to the immersion liquid outlet.

2. The water tank assembly according to claim 1, characterized in that, Along the direction away from the bottom of the first water tank, the outer diameter of the end of the second water tank having the immersion outlet gradually decreases to form a guide slope.

3. The water tank assembly according to claim 1, characterized in that, The height difference between the overflow port of the first water tank and the immersion outlet of the second water tank is between 20mm and 60mm.

4. The water tank assembly according to claim 1, characterized in that, The cross-sectional area of ​​the first water tank is 3 to 6 times that of the cross-sectional area of ​​the second water tank.

5. The water tank assembly according to claim 1, characterized in that, The second water tank is coaxially arranged with the first water tank.

6. The water tank assembly according to any one of claims 1 to 5, characterized in that, The water tank assembly also includes an inlet water tank located at the bottom of the first water tank, the inlet water tank being connected to the first water tank through the bottom of the first water tank; The immersion liquid inlet is located at the bottom of the inlet water tank.

7. The water tank assembly according to claim 6, characterized in that, The bottom of the second water tank is connected to an outlet pipe, which runs longitudinally through the inlet water tank and extends from the bottom of the inlet water tank to the outside of the inlet water tank. The end of the outlet pipe away from the second water tank is connected to the immersion outlet. The longitudinal direction refers to the arrangement direction of the first water tank and the inlet water tank.

8. The water tank assembly according to claim 6, characterized in that, The bottom of the liquid inlet tank is equipped with a small immersion return pipe.

9. The water tank assembly according to claim 8, characterized in that, The flow rate Q of the immersion small reflux pipe 小回 The flow rate Q at the immersion liquid inlet 进 Between 1% and 10%.

10. The water tank assembly according to claim 8, characterized in that, The water tank assembly also includes a third water tank, with the first water tank located inside the third water tank, and the side wall of the third water tank is provided with a large immersion return pipe.

11. The water tank assembly according to claim 10, characterized in that, The third water tank is filled with nitrogen.

12. The water tank assembly according to claim 10, characterized in that, A partition is provided between the side wall of the liquid inlet tank and the side wall of the third tank to isolate the liquid inlet tank from the first tank, the second tank and the third tank respectively. The intermediate partition plate is provided with a plurality of immersion liquid riser holes distributed along a ring interval, and the plurality of immersion liquid riser holes connect the first water tank and the inlet water tank.

13. The water tank assembly according to claim 1, characterized in that, The flow rate Q of the immersion inlet 进 The flow rate Q of the immersion liquid outlet 出 Satisfy: Q 进 3Q 出 .

14. A photolithography machine immersion solution supply system, characterized in that, include: The lithography machine near-end ultrapure water deep purification device, the immersion head, and the water tank assembly according to any one of claims 1 to 13, wherein the outlet of the lithography machine near-end ultrapure water deep purification device is connected to the immersion liquid inlet of the water tank assembly, and the immersion liquid outlet of the water tank assembly is connected to the immersion head.

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