Liquid level control mechanism of wafer cleaning machine

Abstract

The invention relates to the technical field of semiconductor equipment, in particular to a liquid level control mechanism of a wafer cleaning machine, which is characterized in that an SPM cleaning tank, an APM cleaning tank and an HF cleaning tank are respectively connected with a liquid level adjusting box through pipelines; a flowmeter and a pump body are arranged on a pipeline between the liquid level adjusting box and the SPM cleaning tank, a pipeline between the liquid level adjusting box and the APM cleaning tank and a pipeline between the liquid level adjusting box and the HF cleaning tank, and the flowmeter and the pump body are used for pumping cleaning liquid in the SPM cleaning tank, the APM cleaning tank and the HF cleaning tank into the liquid level adjusting box so as to control the liquid level in each cleaning tank; the control box judges the number of the crystals according to the liquid level change before and after the wafers are added into the cleaning tanks, calculates the heating time according to the number of the crystals, the reagent temperature, the required minimum reagent amount and the heating contact surface, and controls the flow meter and the pump body to adjust the liquid level in each cleaning tank. According to the invention, liquid level adjustment is realized based on the wafer handling capacity, the temperature control time and the efficiency so as to ensure that the temperature and the concentration meet the optimal cleaning effect, and the problems of over-etching, wafer surface damage, prolonged cleaning time and poor cleaning effect caused by the influence of liquid level fluctuation on the temperature and the concentration in the cleaning process are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor equipment, and particularly to a liquid level control mechanism for a wafer cleaning machine. Background Art

[0002] Wafer cleaning is one of the crucial steps in the semiconductor manufacturing process. Its purpose is to remove various contaminants on the wafer surface to ensure that subsequent process steps can be carried out on a clean surface.

[0003] Specifically, wafer cleaning refers to using physical or chemical means to remove the tiny particles adhering to the wafer surface. Smaller particles are more difficult to remove because of the strong electrostatic adsorption force between them and the wafer surface, and special treatment is required. There may be organic contaminants such as grease and photoresist residues adhering to the wafer surface, and these contaminants are usually removed by strong oxidants or solvents. The residual metal ions on the wafer surface may lead to a decline in electrical performance and even affect the subsequent processes of the wafer. Therefore, specific chemical solutions are needed for treatment.

[0004] During the wafer cleaning process, liquid level control must be precise. For example, in a chemical cleaning tank, if the liquid level is too high, chemical reagents may overflow, which not only wastes the reagents but also may damage the equipment and the environment; if the liquid level is too low, the wafer may not be completely covered, resulting in incomplete cleaning. The comparative document with the patent number CN216133848U discloses a liquid level monitoring device for a wafer cleaning tank. A diversion pipe is arranged on the upper side of the side wall of the cleaning tank, and a liquid leakage sensor is arranged on the diversion pipe. When the cleaning liquid in the cleaning tank is higher than the installation position of the diversion pipe, it flows along the diversion pipe to the liquid leakage sensor. When the liquid leakage sensor detects a signal, it is judged that there is a risk of liquid leakage in the cleaning tank, so as to monitor the liquid leakage situation of the cleaning tank, avoid the damage of liquid leakage to the machine parts, and avoid safety accidents caused by liquid leakage.

[0005] Although this comparative document can achieve liquid leakage monitoring, when different amounts of crystals are added to the cleaning liquid, the liquid level fluctuation may cause changes in parameters such as the concentration and temperature of the cleaning liquid. If the temperature is too high, the reaction will be too violent and difficult to precisely control, resulting in over-etching and damaging the wafer surface. If the temperature is too low, the reaction rate is slow, the cleaning time is prolonged, and the cleaning effect is poor. For this reason, we propose a liquid level control mechanism for a wafer cleaning machine. Summary of the Invention

[0006] Based on the technical problems existing in the background art, the present invention proposes a liquid level control mechanism for a wafer cleaning machine, which has the characteristics of realizing liquid level adjustment based on the wafer processing amount, temperature control time and efficiency to ensure that both the temperature and concentration meet the best cleaning effect, and solves the problems of over-etching caused by the influence of liquid level fluctuation on temperature and concentration during the cleaning process, damaging the wafer surface, prolonging the cleaning time, and poor cleaning effect.

[0007] The present invention provides the following technical solution: A wafer cleaning machine liquid level control mechanism, including an SPM cleaning tank, an APM cleaning tank, an HF cleaning tank and a fast-drain flushing tank. Liquid level gauges, temperature detection mechanisms and heating mechanisms are provided inside the SPM cleaning tank, the APM cleaning tank and the HF cleaning tank. The SPM cleaning tank, the APM cleaning tank and the HF cleaning tank are respectively connected to a liquid level adjustment tank through pipelines;

[0008] The SPM cleaning tank uses an acidic cleaning agent, a sulfuric acid-hydrogen peroxide mixture (SPM), which can remove organic substances, metal impurities, etc. on the wafer surface. Sulfuric acid has strong oxidizing and dehydrating properties and can decompose organic substances, while hydrogen peroxide can oxidize metal impurities into an ionic state that is easily soluble in water, thereby achieving the purpose of cleaning.

[0009] The APM cleaning tank uses an alkaline cleaning agent, an ammonium hydroxide-hydrogen peroxide mixture (APM), for removing particulate impurities on the wafer surface. The alkaline environment helps the dispersion and suspension of particles, and hydrogen peroxide can slightly oxidize the surface, making the particles easier to be washed away.

[0010] The HF cleaning tank uses hydrofluoric acid for cleaning. The hydrofluoric acid (HF) solution is used to remove the oxide layer on the wafer surface. Hydrofluoric acid can react with silicon dioxide and dissolve the oxide layer to obtain a clean silicon surface.

[0011] The fast-drain flushing tank first sprays deionized water from the upper part of the tank body and injects it from the bottom. After the tank body reaches a certain water volume, the deionized water is quickly drained. While spraying, water continuously enters from both sides at the bottom and then overflows along the perimeter from the upper end of the inner tank. There is a special overflow tank to ensure that the overflowing water does not flow into other cleaning tanks, so that the deionized water inside the tank body can be updated and purified.

[0012] Flow meters and pump bodies are provided on the pipelines between the liquid level adjustment tank and the SPM cleaning tank, the APM cleaning tank and the HF cleaning tank. The flow meters and pump bodies are used to pump the cleaning liquid in the SPM cleaning tank, the APM cleaning tank and the HF cleaning tank into the liquid level adjustment tank to control the liquid levels in each cleaning tank;

[0013] It further includes a control box, which is used to judge the number of crystals according to the liquid level change before and after the wafer is added to the cleaning tank, and calculate the heating time and control the flow meters and pump bodies to adjust the liquid levels in each cleaning tank according to the number of crystals, the temperature of the chemical agent, the required minimum dosage of the chemical agent and the heating contact surface;

[0014] The SPM cleaning tank, the APM cleaning tank and the HF cleaning tank are respectively used for cleaning the wafer with different chemical agents, and the fast-drain flushing tank is used for cleaning particulate impurities and residual chemical reagents on the wafer surface.

[0015] Preferably, the liquid level adjustment tank includes an SPM cleaning liquid level adjustment tank, an APM cleaning liquid level adjustment tank, and an HF cleaning liquid level adjustment tank. The SPM cleaning liquid level adjustment tank is connected to the SPM cleaning tank through an SPM cleaning adjustment pipeline, and a pump body and a flow meter are arranged on the SPM cleaning adjustment pipeline;

[0016] The SPM cleaning liquid level adjustment tank is connected to the SPM cleaning tank through an SPM cleaning adjustment pipeline, and a pump body and a flow meter are arranged on the SPM cleaning adjustment pipeline;

[0017] The APM cleaning liquid level adjustment tank is connected to the APM cleaning tank through an APM cleaning adjustment pipeline, and a pump body and a flow meter are arranged on the APM cleaning adjustment pipeline;

[0018] The HF cleaning liquid level adjustment tank is connected to the HF cleaning tank through an HF cleaning adjustment pipeline, and a pump body and a flow meter are arranged on the HF cleaning adjustment pipeline. The liquid level adjustment tank is used to pump the excess cleaning liquid in the cleaning tank into the liquid level adjustment tank during the process of adjusting the cleaning liquid, so as to reduce the liquid level height in the cleaning tank, facilitate the temperature control of the heating mechanism in the shortest time, and avoid the pollution of the excess cleaning agent. While ensuring the concentration of the cleaning agent, the usage amount of the cleaning agent is saved.

[0019] Preferably, a first liquid level sensor for monitoring the liquid level change is arranged inside the SPM cleaning tank, a first bottom heating plate is installed at the bottom of the SPM cleaning tank, and a first lower heating plate, a first middle heating plate, and a first upper heating plate are sequentially installed on the side of the SPM cleaning tank from bottom to top;

[0020] A hydrogen peroxide concentration detector is arranged inside the SPM cleaning tank, and the hydrogen peroxide concentration detector is used to monitor the hydrogen peroxide concentration in the SPM cleaning liquid; when the H2O2 concentration drops to a certain level (such as below 80% of the initial concentration), a high-purity H2O2 solution is added through the SPM cleaning agent replenishment tank for replenishment to make the H2O2 concentration return to the appropriate range.

[0021] A first vision camera is arranged at the top of the SPM cleaning tank, and a first drain valve is arranged at the bottom. By observing the color and transparency of the cleaning liquid through the first vision camera, if the color of the cleaning liquid becomes significantly darker and turbid, it means that there are too many impurities in the cleaning liquid, and then cycle treatment is required. If the precipitation and color change cannot be removed even through cycle treatment, the cleaning agent needs to be discharged through the first drain valve and then replaced.

[0022] Preferably, a second liquid level sensor for monitoring the liquid level change is arranged inside the APM cleaning tank, a second bottom heating plate is installed at the bottom of the APM cleaning tank, and a second lower heating plate, a second middle heating plate, and a second upper heating plate are sequentially installed on the side of the APM cleaning tank from bottom to top;

[0023] Inside the APM cleaning tank, a pH meter is provided, which is used to monitor the pH change of the APM cleaning agent; when the pH value deviates from the set range (such as pH < 10 or pH > 12), it is adjusted by adding an appropriate amount of NH4OH or H2O.

[0024] On the top of the APM cleaning tank, a second vision camera is provided, and on the bottom, a second drain valve is provided. The second vision camera is used to monitor the precipitation and color change of the APM cleaning agent. The second vision camera checks the appearance of the solution. If precipitation or color change occurs, recycling treatment is required. If the precipitation and color change cannot be removed even after recycling treatment, the cleaning agent needs to be drained through the second drain valve and then replaced.

[0025] Preferably, inside the HF cleaning tank, a third liquid level sensor for monitoring the liquid level change is provided. A third bottom heating plate is installed at the bottom of the HF cleaning tank. From bottom to top, a third lower heating plate, a third middle heating plate, and a third upper heating plate are installed on the side of the HF cleaning tank in sequence;

[0026] Inside the HF cleaning tank, a fluoride ion selective electrode is provided, which is used to monitor the change in the concentration of hydrofluoric acid; the fluoride ion selective electrode detects the concentration of the cleaning solution. Since HF is volatile, the concentration may gradually decrease with the increase of the use time. When the concentration is lower than the process requirement range, the agent needs to be replenished or replaced; when the HF concentration drops to a certain extent (such as less than 70% of the initial concentration), a high-purity HF solution is added for replenishment to maintain a suitable concentration range.

[0027] On the top of the HF cleaning tank, a third vision camera is provided, and on the bottom, a third drain valve is provided. The third vision camera is used to monitor whether there are obvious impurities or precipitates in the HF cleaning agent. Observe whether there are obvious impurities or precipitates in the cleaning solution through the third vision camera, which are formed by the metal ions or other pollutants dissolved from the wafer surface. When obvious impurities or precipitates appear, recycling treatment is carried out. If the obvious impurities or precipitates cannot be removed even after recycling treatment, the cleaning agent needs to be drained through the third drain valve and then replaced.

[0028] Preferably, the SPM cleaning tank is connected to the SPM cleaning agent circulation tank through an SPM circulation inlet pipe and an SPM circulation outlet pipe, and a pump body and a flow meter are provided on the SPM circulation inlet pipe;

[0029] Inside the SPM cleaning agent circulation tank, there is a first filter element for filtering the particulate impurities shed from the surface of the wafer, and an ion exchange resin column for adsorbing and removing metal ions in the solution. A corrosion-resistant precision filter is installed on the circulation tank of the SPM cleaning tank, specifically using a filter element made of polytetrafluoroethylene with a filtration accuracy of 0.1 - 1 micron, which is used to intercept the particulate impurities shed from the wafer surface during the cleaning process. At the same time, an ion exchange resin column is set up, and strongly acidic cation exchange resin is selected to adsorb and remove metal ions in the solution to maintain the purity of the cleaning solution.

[0030] Preferably, the APM cleaning tank is connected to the APM cleaning agent circulation tank through the APM circulation inlet pipe and the APM circulation outlet pipe, and a pump body and a flow meter are arranged on the APM circulation inlet pipe;

[0031] Inside the APM cleaning agent circulation tank, there are a coarse filter screen and a fine filter screen for filtering the APM cleaning agent, and a first sedimentation tank is arranged at the bottom of the coarse filter screen and the fine filter screen; in the circulation loop of the APM cleaning solution, a multi-layer filtering device is installed, including a coarse filter screen, that is, a 5-micron filter screen, and a fine filter screen, that is, a 0.2-micron microporous filter membrane, to remove particulate impurities in the solution. At the same time, a first sedimentation tank is set up to make the insoluble impurities in the solution precipitate by gravity, and the first sedimentation tank is cleaned regularly.

[0032] A membrane module is installed at the position corresponding to the APM circulation outlet pipe in the APM cleaning agent circulation tank, and the membrane module adopts at least one of ultrafiltration membrane and nanofiltration membrane;

[0033] The APM cleaning solution is separated by using ultrafiltration membrane or nanofiltration membrane technology. The ultrafiltration membrane can intercept macromolecular organic matters and colloidal particles in the solution, while the nanofiltration membrane can separate out some metal ions and small molecular impurities, and the clarified liquid passing through the membrane can be returned to the cleaning tank for recycling. The membrane module needs to be cleaned and maintained regularly, and a combination of backwashing and chemical cleaning can be adopted, such as using a mild alkaline cleaning agent (sodium carbonate solution) for chemical cleaning to restore the flux of the membrane.

[0034] Preferably, the HF cleaning tank is connected to the HF cleaning agent circulation tank through the HF circulation inlet pipe and the HF circulation outlet pipe, and a pump body and a flow meter are arranged on the HF cleaning agent circulation tank;

[0035] Inside the HF cleaning agent circulation tank, there is a second filter element for filtering out the metal impurities and particles dissolved from the wafer surface. Inside the HF cleaning agent circulation tank, there are a precipitant addition pipe, a second sedimentation tank, and a sediment filter screen for filtering the precipitate.

[0036] Install a filter resistant to hydrofluoric acid corrosion in the circulation tank of the HF cleaning solution. For example, use a filter element two made of silicon carbide, and set the filtration accuracy at 0.5 - 2 microns to filter out metal impurities and particles dissolved from the wafer surface. At the same time, set a precipitation tank two for reaction, add an appropriate amount of precipitant (sodium hydroxide) to it, so that metal ions in the solution form hydroxide precipitates, and then remove the precipitates through a precipitation filter screen.

[0037] Preferably, the SPM cleaning tank, APM cleaning tank, and HF cleaning tank are respectively connected to the replenishment tank through pipelines, and chemical agents are filled in the replenishment tank. Pumps and flow meters are provided on the pipelines of each replenishment tank.

[0038] Preferably, the replenishment tank includes an SPM cleaning agent replenishment tank, an APM cleaning agent replenishment tank, and an HF cleaning agent replenishment tank;

[0039] The SPM cleaning agent replenishment tank is connected to the SPM cleaning tank through an SPM cleaning agent replenishment pipeline, the APM cleaning agent replenishment tank is connected to the APM cleaning tank through an APM cleaning agent replenishment pipeline, and the HF cleaning agent replenishment tank is connected to the HF cleaning tank through an HF cleaning agent replenishment pipeline.

[0040] The SPM cleaning agent replenishment tank is filled with any one or more of the acidic cleaning agent sulfuric acid - hydrogen peroxide mixture (SPM), sulfuric acid solution, and hydrogen peroxide solution. The APM cleaning agent replenishment tank is filled with any one or more of the alkaline cleaning agent ammonium hydroxide - hydrogen peroxide mixture (APM), ammonium hydroxide solution, and hydrogen peroxide solution. The HF cleaning agent replenishment tank is filled with hydrofluoric acid (HF) solution.

[0041] The present invention provides a wafer cleaning machine liquid level control mechanism. According to the change in the liquid level of the cleaning solution before and after adding wafers to the cleaning tank, the number of wafers added to the cleaning solution is judged. Then, according to the minimum amount of cleaning solution required for the number of wafers, as well as the heating time and heating efficiency required at different liquid levels, the liquid level of the cleaning solution is adjusted to achieve the optimal liquid level. This optimal liquid level can not only achieve temperature control in the shortest time, but also perfectly cover all wafers, while saving cleaning solution to ensure that the temperature and concentration meet the best cleaning effect, solving the problems of over - etching caused by liquid level fluctuations affecting temperature and concentration during the cleaning process, damaging the wafer surface, prolonging the cleaning time, and poor cleaning effect. Brief Description of the Drawings

[0042] Figure 1 It is a schematic structural diagram of the present invention;

[0043] Figure 2 It is a schematic structural diagram of the SPM cleaning tank of the present invention;

[0044] Figure 3Schematic diagram of the APM cleaning tank structure of the present invention;

[0045] Figure 4 Schematic diagram of the HF cleaning tank structure of the present invention;

[0046] Figure 5 Schematic diagram of the SPM cleaning agent circulation tank structure of the present invention;

[0047] Figure 6 Schematic diagram of the APM cleaning agent circulation tank structure of the present invention;

[0048] Figure 7 Schematic diagram of the HF cleaning agent circulation tank structure of the present invention.

[0049] In the figure: 1. SPM cleaning tank; 101. First liquid level sensor; 102. First bottom heating plate; 103. First lower heating plate; 104. First middle heating plate; 105. First upper heating plate; 106. Hydrogen peroxide concentration detector; 107. First vision camera; 108. First drain valve; 2. APM cleaning tank; 201. Second liquid level sensor; 202. Second bottom heating plate; 203. Second lower heating plate; 204. Second middle heating plate; 205. Second upper heating plate; 206. pH meter; 207. Second vision camera; 208. Second drain valve; 3. HF cleaning tank; 301. Third liquid level sensor; 302. Third bottom heating plate; 303. Third lower heating plate; 304. Third middle heating plate; 305. Third upper heating plate; 306. Fluoride ion selective electrode; 307. Third vision camera; 308. Third drain valve; 4. Quick drain flushing tank; 5. SPM cleaning liquid level adjustment tank; 51. SPM cleaning adjustment pipeline; 6. APM cleaning liquid level adjustment tank; 61. APM cleaning adjustment pipeline; 7. HF cleaning liquid level adjustment tank; 71. HF cleaning adjustment pipeline; 8. SPM cleaning agent replenishment tank; 81. SPM cleaning agent replenishment pipeline; 9. APM cleaning agent replenishment tank; 91. APM cleaning agent replenishment pipeline; 10. HF cleaning agent replenishment tank; 1001. HF cleaning agent replenishment pipeline; 11. SPM cleaning agent circulation tank; 1101. SPM circulation inlet pipe; 1102. SPM circulation outlet pipe; 1103. Filter element 1; 1104. Ion exchange resin column; 12. APM cleaning agent circulation tank; 1201. APM circulation inlet pipe; 1202. APM circulation outlet pipe; 1203. Coarse filter screen; 1204. Fine filter screen; 1205. First sedimentation tank; 1206. Membrane module; 13. HF cleaning agent circulation tank; 1301. HF circulation inlet pipe; 1302. HF circulation outlet pipe; 1303. Filter element 2; 1304. Precipitant addition pipe; 1305. Second sedimentation tank; 1306. Sediment filter screen; 14. Control box. Detailed implementation manners

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0051] As Figure 1 shown, the present invention provides a technical solution: a liquid level control mechanism for a wafer cleaning machine, including an SPM cleaning tank 1, an APM cleaning tank 2, an HF cleaning tank 3, and a quick-drain flushing tank 4. Liquid level gauges, temperature detection mechanisms, and heating mechanisms are provided inside the SPM cleaning tank 1, the APM cleaning tank 2, and the HF cleaning tank 3. The SPM cleaning tank 1, the APM cleaning tank 2, and the HF cleaning tank 3 are respectively connected to a liquid level adjustment tank through pipelines.

[0052] The SPM cleaning tank 1 uses an acidic cleaning agent, a sulfuric acid-hydrogen peroxide mixture (SPM), which can remove organic substances, metal impurities, etc. on the surface of the wafer. Sulfuric acid has strong oxidizing and dehydrating properties and can decompose organic substances, while hydrogen peroxide can oxidize metal impurities into an ionic state that is easily soluble in water, thereby achieving the purpose of cleaning.

[0053] The APM cleaning tank 2 uses an alkaline cleaning agent, an ammonium hydroxide-hydrogen peroxide mixture (APM), for removing particulate impurities on the surface of the wafer. The alkaline environment helps the dispersion and suspension of particles, and hydrogen peroxide can slightly oxidize the surface, making the particles easier to be washed away.

[0054] The HF cleaning tank 3 uses hydrofluoric acid for cleaning. The hydrofluoric acid (HF) solution is used to remove the oxide layer on the surface of the wafer. Hydrofluoric acid can react with silicon dioxide to dissolve the oxide layer, thereby obtaining a clean silicon surface.

[0055] The quick-drain flushing tank 4 first sprays deionized water from the upper part of the tank body and injects it from the bottom. After the tank body reaches a certain water volume, the deionized water is quickly drained. While spraying, water continuously enters from both sides at the bottom and then overflows along the periphery from the upper end of the inner tank. There is a special overflow tank to ensure that the overflowing water does not flow into other cleaning tanks, so that the deionized water inside the tank body can be updated and purified.

[0056] Flow meters and pump bodies are provided on the pipelines between the liquid level adjustment tank and the SPM cleaning tank 1, the APM cleaning tank 2, and the HF cleaning tank 3. The flow meters and pump bodies are used to pump the cleaning liquid in the SPM cleaning tank 1, the APM cleaning tank 2, and the HF cleaning tank 3 into the liquid level adjustment tank to control the liquid levels in each cleaning tank;

[0057] It further includes a control box 14 which is used to judge the number of crystals according to the liquid level change before and after the wafers are added into the cleaning tank, and calculate the heating time and control the flowmeter and the pump body to adjust the liquid levels in each cleaning tank according to the number of crystals, the reagent temperature, the required minimum reagent dosage and the heating contact surface;

[0058] The SPM cleaning tank 1, the APM cleaning tank 2 and the HF cleaning tank 3 are respectively used for cleaning the wafers with different chemical reagents, and the quick drain rinsing tank 4 is used for cleaning the particulate impurities and residual chemical reagents on the wafer surface.

[0059] The present invention judges the number of wafers added into the cleaning liquid according to the liquid level change of the cleaning liquid before and after adding into the cleaning tank. Then, according to the minimum amount of cleaning liquid required by the number of wafers, as well as the heating time and heating efficiency required at different liquid levels, the liquid level of the cleaning liquid is adjusted to achieve the optimal liquid level. This optimal liquid level can not only achieve temperature control in the shortest time, but also perfectly cover all wafers, while saving the cleaning liquid to ensure that the temperature and concentration meet the best cleaning effect. Moreover, the accuracy and stability of the liquid level control are ensured.

[0060] In the chemical cleaning tank, too high a liquid level may cause the chemical reagent to overflow, which not only wastes the reagent, but also may damage the equipment and the environment; too low a liquid level may not be able to completely cover the wafers, resulting in incomplete cleaning. The accuracy of the liquid level control of the present invention is within ±1 mm.

[0061] A stable liquid level is crucial for ensuring the consistency of the cleaning effect. Liquid level fluctuations may cause changes in parameters such as the concentration and temperature of the cleaning liquid, thus affecting the cleaning effect. Especially in the multi-step cleaning process, the stability of the liquid level is also very important for avoiding cross-contamination between different cleaning steps.

[0062] In another embodiment, the liquid level adjustment tank includes an SPM cleaning liquid level adjustment tank 5, an APM cleaning liquid level adjustment tank 6, and an HF cleaning liquid level adjustment tank 7. The SPM cleaning liquid level adjustment tank 5 is connected to the SPM cleaning tank 1 through an SPM cleaning adjustment pipeline 51, and a pump body and a flowmeter are arranged on the SPM cleaning adjustment pipeline 51;

[0063] The SPM cleaning liquid level adjustment tank 5 is connected to the SPM cleaning tank 1 through an SPM cleaning adjustment pipeline 51, and a pump body and a flowmeter are arranged on the SPM cleaning adjustment pipeline 51;

[0064] The APM cleaning liquid level adjustment tank 6 is connected to the APM cleaning tank 2 through an APM cleaning adjustment pipeline 61, and a pump body and a flowmeter are arranged on the APM cleaning adjustment pipeline 61;

[0065] The HF cleaning liquid level regulating tank 7 is connected to the HF cleaning tank 3 through the HF cleaning regulating pipeline 71, and a pump body and a flow meter are provided on the HF cleaning regulating pipeline 71. The liquid level regulating tank is used to pump the excess cleaning liquid in the cleaning tank into the liquid level regulating tank during the process of regulating the cleaning liquid, so as to reduce the liquid level height in the cleaning tank, facilitate the temperature control of the heating mechanism in the shortest time, avoid the pollution of the excess cleaning agent, ensure the concentration of the cleaning agent, and save the consumption of the cleaning agent.

[0066] Specifically, during the wafer cleaning process, the liquid level regulating tank undertakes the key liquid level regulation responsibility. When the liquid level of the cleaning liquid in the cleaning tank is too high, the liquid level regulating tank starts the suction mechanism and quickly pumps the excess cleaning liquid in the cleaning tank into its own tank through the connecting pipeline. This operation can effectively reduce the liquid level height in the cleaning tank, enabling the heating mechanism to heat the remaining cleaning liquid more efficiently, thereby achieving precise temperature control in the shortest time. At the same time, the excess cleaning liquid is properly stored in the liquid level regulating tank, avoiding its continuous exposure in the cleaning tank, reducing the risk of contamination, effectively ensuring the concentration stability of the cleaning liquid, reducing unnecessary cleaning agent loss, and achieving effective resource conservation.

[0067] When a large number of wafers are put into the cleaning tank, resulting in insufficient cleaning liquid level, the liquid level regulating tank can timely return the stored cleaning liquid to the cleaning tank to ensure that the cleaning process is not affected by too low a liquid level. In addition, the liquid level regulating tank can also, according to actual needs, cooperate with the replenishment tank to add new cleaning agent in a timely manner to maintain the best cleaning efficiency of the cleaning liquid.

[0068] In another embodiment, the SPM cleaning tank 1, the APM cleaning tank 2, and the HF cleaning tank 3 are respectively connected to the replenishment tank through pipelines, and chemical agents are filled in the replenishment tank. Pump bodies and flow meters are provided on the pipelines of each replenishment tank.

[0069] The replenishment tank includes an SPM cleaning agent replenishment tank 8, an APM cleaning agent replenishment tank 9, and an HF cleaning agent replenishment tank 10;

[0070] The SPM cleaning agent replenishment tank 8 is connected to the SPM cleaning tank 1 through the SPM cleaning agent replenishment pipeline 81, the APM cleaning agent replenishment tank 9 is connected to the APM cleaning tank 2 through the APM cleaning agent replenishment pipeline 91, and the HF cleaning agent replenishment tank 10 is connected to the HF cleaning tank 3 through the HF cleaning agent replenishment pipeline 1001.

[0071] The SPM cleaning agent replenishing tank 8 is filled with any one or more of the acidic cleaning agents sulfuric acid-hydrogen peroxide mixture (SPM), sulfuric acid solution, and hydrogen peroxide solution. The APM cleaning agent replenishing tank 9 is filled with any one or more of the alkaline cleaning agents ammonium hydroxide-hydrogen peroxide mixture (APM), ammonium hydroxide solution, and hydrogen peroxide solution. The HF cleaning agent replenishing tank 10 is filled with hydrofluoric acid (HF) solution.

[0072] After repeated use, if the cleaning liquid becomes obviously darker in color or turbid, it indicates that a large amount of impurities have been mixed into the cleaning liquid. At this time, the control box 14 will introduce this part of the cleaning liquid into the circulation treatment system. The circulation treatment system can effectively remove various impurities, precipitation and metal ions in the cleaning liquid by means of filtering, adsorption and other technical means, so that the cleaning liquid can be restored to a pure state close to the original as much as possible so that it can be put into use again.

[0073] However, if after multiple cycles, the precipitation in the cleaning solution still persists and the color does not improve significantly, this means that the cleaning solution has been seriously contaminated and cannot be restored through conventional cycles. In this case, the control box 14 will open the drain valve to safely discharge the ineffective cleaning solution from the system, and then inject new cleaning solution from the replenishment tank to ensure that the entire cleaning process can run continuously and stably, and the quality of wafer cleaning is not affected.

[0074] like Figure 2 As shown, in another embodiment, a first liquid level sensor 101 for monitoring liquid level changes is provided inside the SPM cleaning tank 1, a first bottom heating plate 102 is installed at the bottom of the SPM cleaning tank 1, and a first lower heating plate 103, a first middle heating plate 104, and a first upper heating plate 105 are installed on the side of the SPM cleaning tank 1 from bottom to top;

[0075] A hydrogen peroxide concentration detector 106 is provided inside the SPM cleaning tank 1, and the hydrogen peroxide concentration detector 106 is used to monitor the hydrogen peroxide concentration in the SPM cleaning solution; when the H2O2 concentration drops to a certain level (such as lower than 80% of the initial concentration), a high-purity H2O2 solution is added through the SPM cleaning agent replenishing box to replenish the H2O2 concentration to restore it to an appropriate range.

[0076] A first visual camera 107 is provided at the top of the SPM cleaning tank 1, and a first liquid discharge valve 108 is provided at the bottom. The color and transparency of the cleaning liquid are observed through the first visual camera 107. If the color of the cleaning liquid becomes obviously darker and turbid, it means that there are too many impurities in the cleaning liquid, and a circulation treatment is required. If the circulation treatment cannot remove the precipitation and color change, the cleaning agent needs to be discharged through the first liquid discharge valve 108 and then replaced.

[0077] like Figure 3As shown, in another embodiment, a second liquid level sensor 201 for monitoring liquid level changes is provided inside the APM cleaning tank 2, a second bottom heating plate 202 is installed at the bottom of the APM cleaning tank 2, and a second lower heating plate 203, a second middle heating plate 204, and a second upper heating plate 205 are installed on the side of the APM cleaning tank 2 from bottom to top;

[0078] A pH meter 206 is provided inside the APM cleaning tank 2, and the pH meter 206 is used to monitor the pH change of the APM cleaning agent; when the pH value deviates from the set range (such as pH<10 or pH>12), it is adjusted by adding an appropriate amount of NH4OH or H2O.

[0079] A second visual camera 207 is provided on the top of the APM cleaning tank 2, and a second drain valve 208 is provided on the bottom. The second visual camera 207 is used to monitor the precipitation and color change of the APM cleaning agent. The second visual camera 207 checks the appearance of the solution. If precipitation or color change occurs, a circulation treatment is required. If the circulation treatment cannot remove the precipitation and color change, the cleaning agent needs to be discharged through the second drain valve 208 and replaced.

[0080] like Figure 4 As shown, in another embodiment, a third liquid level sensor 301 for monitoring liquid level changes is provided inside the HF cleaning tank 3, a third bottom heating plate 302 is installed at the bottom of the HF cleaning tank 3, and a third lower heating plate 303, a third middle heating plate 304, and a third upper heating plate 305 are installed on the side of the HF cleaning tank 3 from bottom to top;

[0081] A fluorine ion selective electrode 306 is provided inside the HF cleaning tank 3, and the fluorine ion selective electrode 306 is used to monitor the change of hydrofluoric acid concentration; the fluorine ion selective electrode 306 detects the concentration of the cleaning solution. Since HF is volatile, the concentration may gradually decrease with the increase of the use time. When the concentration is lower than the range required by the process, the agent needs to be supplemented or replaced; when the HF concentration drops to a certain level (such as lower than 70% of the initial concentration), high-purity HF solution is added for supplementation to maintain a suitable concentration range.

[0082] A third visual camera 307 is provided at the top of the HF cleaning tank 3, and a third drain valve 308 is provided at the bottom. The third visual camera 307 is used to monitor whether there are obvious impurities or precipitation in the HF cleaning agent. The third visual camera 307 is used to observe whether there are obvious impurities or precipitation in the cleaning solution, which are formed by metal ions or other pollutants dissolved from the surface of the wafer. When obvious impurities or precipitation appear, a circulation treatment is performed. If the circulation treatment cannot remove obvious impurities or precipitation, the cleaning agent needs to be discharged through the third drain valve 308 and replaced.

[0083] like Figures 2-4The inner wall of the cleaning tank shown adopts an innovative layered heating design, and a lower heating sheet, a middle heating sheet, and an upper heating sheet are installed in sequence from the bottom upwards. Each heating sheet is independent, and can accurately turn on or off the heating elements in the corresponding area according to the different states of the cleaning liquid level, realizing an efficient and energy-saving heating process.

[0084] The liquid level sensor is closely attached to the side of the cleaning tank and uses ultrasonic or static pressure measurement technology to monitor the cleaning liquid level in real time and accurately. The temperature sensor is cleverly arranged inside the cleaning tank, and through thermistor or thermocouple technology, it can quickly and accurately sense the subtle changes in the temperature of the cleaning liquid, providing key data support for subsequent control decisions.

[0085] The control box 14 adopts a PLC controller. Through a high-speed data transmission line, it receives the data information fed back from the liquid level sensor and the temperature sensor in real time, and intelligently regulates the working state of the heating sheet and the cleaning liquid level according to the pre-set complex algorithm.

[0086] When the liquid level sensor detects that the cleaning liquid level is at a low level, the controller only sends an opening instruction to the bottom heating sheet. This is because at this time only the bottom heating sheet is in contact with the cleaning liquid, and it can accurately heat the limited cleaning liquid, avoiding energy waste. As the liquid level gradually rises, when it reaches the middle position, the controller will turn on both the lower and middle heating sheets to meet the heat demand for the increased volume of the cleaning liquid. When the liquid level rises to the upper area, all three heating sheets will be turned on to ensure that the entire cleaning liquid is evenly heated.

[0087] Based on the principle of the contact area between liquid and solid surface in physics, by accurately measuring the volume of the cleaning liquid and combining the specific shape parameters of the cleaning tank (such as the radius of a cylindrical container, the length and width of a cuboid container, etc.), the liquid level height that can maximize the contact area between the cleaning liquid and the heating plate is calculated using the corresponding mathematical formula. For example, for a cylindrical container, according to the volume formula V = πr 2 h (where V is the volume, r is the radius, and h is the height), the liquid level height h value that maximizes the contact area can be deduced under a given volume.

[0088] In order to maintain the liquid level at the optimal height, the controller accurately controls the inlet valve and the drain valve by comparing the real-time liquid level data with the calculated optimal liquid level value. When the real-time liquid level is lower than the optimal liquid level, the controller sends an instruction to open the inlet valve, allowing the cleaning liquid to flow in and the liquid level to gradually rise; conversely, when the real-time liquid level is higher than the optimal liquid level, the drain valve opens, and the excess cleaning liquid is discharged, causing the liquid level to drop until it reaches the optimal liquid level state.

[0089] Such as Figure 5As shown, in another embodiment, the SPM cleaning tank 1 is connected to the SPM cleaning chemical circulating tank 11 through the SPM circulating inlet pipe 1101 and the SPM circulating outlet pipe 1102, and a pump body and a flow meter are provided on the SPM circulating inlet pipe 1101;

[0090] Inside the SPM cleaning chemical circulating tank 11, a first filter element 1103 for filtering the particulate impurities shed from the surface of the wafer and an ion exchange resin column 1104 for adsorbing and removing metal ions in the solution are provided. A corrosion-resistant precision filter is installed on the circulating tank of the SPM cleaning tank 1. Specifically, a filter element made of polytetrafluoroethylene is used, and the filtration accuracy reaches 0.1 - 1 micron, which is used to intercept the particulate impurities shed from the surface of the wafer during the cleaning process. At the same time, an ion exchange resin column 1104 is provided, and strongly acidic cation exchange resin is selected to adsorb and remove metal ions in the solution and maintain the purity of the cleaning solution.

[0091] As Figure 6 shown, in another embodiment, the APM cleaning tank 2 is connected to the APM cleaning chemical circulating tank 12 through the APM circulating inlet pipe 1201 and the APM circulating outlet pipe 1202, and a pump body and a flow meter are provided on the APM circulating inlet pipe 1201;

[0092] Inside the APM cleaning chemical circulating tank 12, a coarse filter screen 1203 and a fine filter screen 1204 for filtering the APM cleaning chemical are provided, and a first sedimentation tank 1205 is provided at the bottom of the coarse filter screen 1203 and the fine filter screen 1204; in the circulation loop of the APM cleaning solution, a multi-layer filtering device is installed, including the coarse filter screen 1203, that is, a 5-micron filter screen, and the fine filter screen 1204, that is, a 0.2-micron microporous membrane, to remove particulate impurities in the solution. At the same time, the first sedimentation tank 1205 is provided to make the insoluble impurities in the solution precipitate by gravity, and the first sedimentation tank 1205 is cleaned regularly.

[0093] A membrane module 1206 is installed at the position corresponding to the APM circulating outlet pipe 1202 in the APM cleaning chemical circulating tank 12, and the membrane module 1206 adopts at least one of ultrafiltration membrane and nanofiltration membrane;

[0094] The ultrafiltration membrane or nanofiltration membrane technology is used to separate the APM cleaning solution. The ultrafiltration membrane can retain macromolecular organic matters and colloidal particles in the solution, while the nanofiltration membrane can separate out some metal ions and small molecule impurities, and the clarified liquid passing through the membrane can be returned to the cleaning tank for recycling. The membrane module 1206 needs to be cleaned and maintained regularly, and a combination of backwashing and chemical cleaning can be adopted, such as using a mild alkaline cleaning agent (sodium carbonate solution) for chemical cleaning to restore the flux of the membrane.

[0095] As Figure 7As shown, in another embodiment, the HF cleaning tank 3 is connected to the HF cleaning agent circulation tank 13 through the HF circulation inlet pipe 1301 and the HF circulation outlet pipe 1302, and a pump body and a flow meter are provided on the HF cleaning agent circulation tank 13;

[0096] A filter element two 1303 for filtering out metal impurities and particles dissolved from the wafer surface is provided in the HF cleaning agent circulation tank 13. A precipitant addition pipe 1304, a precipitation tank two 1305, and a precipitation filter screen 1306 for filtering the precipitate are provided in the HF cleaning agent circulation tank 13.

[0097] In the circulation tank of the HF cleaning solution, a filter resistant to hydrofluoric acid corrosion is installed, such as the filter element two 1303 made of silicon carbide, and the filtration accuracy is set at 0.5 - 2 microns for filtering out metal impurities and particles dissolved from the wafer surface. At the same time, a precipitation tank two 1305 for reaction is set, and an appropriate amount of precipitant (sodium hydroxide) is added thereto to form metal hydroxide precipitates in the solution, and then the precipitate is removed through the precipitation filter screen 1306.

[0098] In the present invention, the high-precision data acquisition of the liquid level sensor and the temperature sensor, as well as the complex algorithm processing of the intelligent controller, ensure the precise control of the heating process and the liquid level height. Whether during the liquid level change or the temperature adjustment process, the system can quickly respond and make accurate control decisions, avoiding problems such as overheating, overcooling of the cleaning solution or abnormal liquid level caused by control errors, thereby improving the quality and stability of wafer cleaning.

[0099] Through the liquid level-related heating sheet control strategy, the ineffective heating of the entire cleaning tank space when the liquid level is low is avoided, greatly reducing the energy consumption. At the same time, the optimal liquid level height is accurately calculated and maintained, maximizing the contact area between the cleaning solution and the heating sheet, completing the heating process in the shortest time, and improving the energy utilization efficiency. Compared with the traditional non-layered heating system, it can significantly reduce the energy consumption and reduce the production cost.

[0100] The layered heating sheet design makes the heat load borne by each heating sheet during operation more uniform, reducing the risk of damage to the heating sheet caused by local overheating or frequent startup and shutdown. At the same time, the precise liquid level control also reduces the risk of physical damage to the heating sheet and other components of the cleaning tank caused by too high or too low liquid level, thereby effectively extending the service life of the entire heating system and reducing the equipment maintenance and replacement costs.

[0101] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A liquid level control mechanism for a wafer cleaning machine, comprising an SPM cleaning tank (1), an APM cleaning tank (2), an HF cleaning tank (3) and a quick-drain rinsing tank (4), characterized in that: The SPM cleaning tank (1), APM cleaning tank (2), and HF cleaning tank (3) are each internally provided with a liquid level gauge, a temperature detection mechanism, and a heating mechanism. The SPM cleaning tank (1), APM cleaning tank (2), and HF cleaning tank (3) are respectively connected to a liquid level adjustment tank through pipelines; A flow meter and a pump body are provided on the pipelines between the liquid level adjustment tank and the SPM cleaning tank (1), APM cleaning tank (2), and HF cleaning tank (3). The flow meter and the pump body are used to pump the cleaning liquid in the SPM cleaning tank (1), APM cleaning tank (2), and HF cleaning tank (3) into the liquid level adjustment tank to control the liquid level in each cleaning tank; It further includes a control box (14). The control box (14) is used to judge the number of crystals according to the liquid level change before and after the wafer is added to the cleaning tank, and calculate the heating time and control the flow meter and the pump body to adjust the liquid level in each cleaning tank according to the number of crystals, the chemical agent temperature, the required minimum chemical agent amount, and the heating contact surface; The SPM cleaning tank (1), APM cleaning tank (2), and HF cleaning tank (3) are respectively used to clean the wafer with different chemical agents, and the quick drain rinsing tank (4) is used to clean the particulate impurities and residual chemical reagents on the wafer surface.

2. The liquid level control mechanism of a wafer cleaning machine according to claim 1, characterized in that: The liquid level adjustment tank includes an SPM cleaning liquid level adjustment tank (5), an APM cleaning liquid level adjustment tank (6), and an HF cleaning liquid level adjustment tank (7). The SPM cleaning liquid level adjustment tank (5) is connected to the SPM cleaning tank (1) through the APM cleaning liquid level adjustment tank (6), and a pump body and a flow meter are provided on the APM cleaning liquid level adjustment tank (6); The SPM cleaning liquid level adjustment tank (5) is connected to the SPM cleaning tank (1) through an SPM cleaning adjustment pipeline (51), and a pump body and a flow meter are provided on the SPM cleaning adjustment pipeline (51); The APM cleaning liquid level adjustment tank (6) is connected to the APM cleaning tank (2) through an APM cleaning adjustment pipeline (61), and a pump body and a flow meter are provided on the APM cleaning adjustment pipeline (61); The HF cleaning liquid level adjustment tank (7) is connected to the HF cleaning tank (3) through an HF cleaning adjustment pipeline (71), and a pump body and a flow meter are provided on the HF cleaning adjustment pipeline (71).

3. The liquid level control mechanism of a wafer cleaning machine according to claim 1, characterized in that: A first liquid level sensor (101) for monitoring the liquid level change is provided inside the SPM cleaning tank (1). A first bottom heating plate (102) is installed at the bottom of the SPM cleaning tank (1). From bottom to top, a first lower heating plate (103), a first middle heating plate (104), and a first upper heating plate (105) are installed on the side of the SPM cleaning tank (1) in sequence; A hydrogen peroxide concentration detector (106) is provided inside the SPM cleaning tank (1). The hydrogen peroxide concentration detector (106) is used to monitor the hydrogen peroxide concentration in the SPM cleaning liquid; A first vision camera (107) is provided at the top of the SPM cleaning tank (1), and a first drain valve (108) is provided at the bottom. The first vision camera (107) is used to monitor the color and transparency of the SPM cleaning agent.

4. A liquid level control mechanism for a wafer cleaning machine according to claim 1, characterized in that: Inside the APM cleaning tank (2), a second liquid level sensor (201) for monitoring liquid level changes is provided. A second bottom heating plate (202) is installed at the bottom of the APM cleaning tank (2). From bottom to top, a second lower heating plate (203), a second middle heating plate (204), and a second upper heating plate (205) are successively installed on the side of the APM cleaning tank (2); A pH meter (206) is provided inside the APM cleaning tank (2), and the pH meter (206) is used to monitor the pH change of the APM cleaning agent; A second vision camera (207) is provided at the top of the APM cleaning tank (2), and a second drain valve (208) is provided at the bottom. The second vision camera (207) is used to monitor the precipitation and color change of the APM cleaning agent.

5. The liquid level control mechanism of a wafer cleaning machine according to claim 1, characterized in that: Inside the HF cleaning tank (3), a third liquid level sensor (301) for monitoring liquid level changes is provided. A third bottom heating plate (302) is installed at the bottom of the HF cleaning tank (3). From bottom to top, a third lower heating plate (303), a third middle heating plate (304), and a third upper heating plate (305) are successively installed on the side of the HF cleaning tank (3); A fluoride ion selective electrode (306) is provided inside the HF cleaning tank (3), and the fluoride ion selective electrode (306) is used to monitor the change in hydrofluoric acid concentration; A third vision camera (307) is provided at the top of the HF cleaning tank (3), and a third drain valve (308) is provided at the bottom. The third vision camera (307) is used to monitor whether there are obvious impurities or precipitates in the HF cleaning agent.

6. The liquid level control mechanism of a wafer cleaning machine according to claim 3, characterized in that: The SPM cleaning tank (1) is connected to the SPM cleaning agent circulation tank (11) through an SPM circulation inlet pipe (1101) and an SPM circulation outlet pipe (1102), and a pump body and a flow meter are provided on the SPM circulation inlet pipe (1101); Inside the SPM cleaning agent circulation tank (11), a first filter element (1103) for filtering particulate impurities shed from the surface of the wafer and an ion exchange resin column (1104) for adsorbing and removing metal ions in the solution are provided.

7. A liquid level control mechanism of a wafer cleaning machine according to claim 4, characterized in that: The APM cleaning tank (2) is connected to the APM cleaning agent circulation tank (12) through an APM circulation inlet pipe (1201) and an APM circulation outlet pipe (1202), and a pump body and a flow meter are provided on the APM circulation inlet pipe (1201); Inside the APM cleaning agent circulation tank (12), a coarse filter screen (1203) and a fine filter screen (1204) for filtering the APM cleaning agent are provided, and a first sedimentation tank (1205) is provided at the bottom of the coarse filter screen (1203) and the fine filter screen (1204); A membrane module (1206) is installed at the position corresponding to the APM circulation outlet pipe (1202) in the APM cleaning agent circulation tank (12), and the membrane module (1206) adopts at least one of an ultrafiltration membrane and a nanofiltration membrane; The ultrafiltration membrane is used to intercept macromolecular organic matters and colloidal particles in the APM cleaning agent, and the nanofiltration membrane is used to separate metal ions and small molecule impurities in the APM cleaning agent.

8. A liquid level control mechanism for a wafer cleaning machine according to claim 5, characterized in that: The HF cleaning tank (3) is connected to the HF cleaning chemical circulating tank (13) through an HF circulating liquid inlet pipe (1301) and an HF circulating liquid outlet pipe (1302), and a pump body and a flowmeter are provided on the HF cleaning chemical circulating tank (13); A second filter element (1303) for filtering out metal impurities and particles dissolved from the surface of the wafer is provided in the HF cleaning chemical circulating tank (13). A precipitant addition pipe (1304), a second sedimentation tank (1305), and a sediment filter screen (1306) for filtering the precipitate are provided in the HF cleaning chemical circulating tank (13).

9. The liquid level control mechanism of a wafer cleaning machine according to claim 1, characterized in that: The SPM cleaning tank (1), the APM cleaning tank (2), and the HF cleaning tank (3) are respectively connected to a replenishment tank through pipes, and chemical agents are filled in the replenishment tank. A pump body and a flowmeter are provided on the pipes of each replenishment tank.

10. The liquid level control mechanism of a wafer cleaning machine according to claim 9, characterized in that: The replenishment tank includes an SPM cleaning chemical replenishment tank (8), an APM cleaning chemical replenishment tank (9), and an HF cleaning chemical replenishment tank (10); The SPM cleaning chemical replenishment tank (8) is connected to the SPM cleaning tank (1) through an SPM cleaning chemical replenishment pipe (81), the APM cleaning chemical replenishment tank (9) is connected to the APM cleaning tank (2) through an APM cleaning chemical replenishment pipe (91), and the HF cleaning chemical replenishment tank (10) is connected to the HF cleaning tank (3) through an HF cleaning chemical replenishment pipe (1001).

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