Thin film evaporation tetramethylammonium hydroxide pentahydrate crystal dehydration device and method based on dynamic liquid supply

Abstract

The invention discloses a film evaporation tetramethylammonium hydroxide pentahydrate crystal dehydration device and method based on dynamic liquid supply. Raw material liquid of the method is preheated by an evaporation chamber and is primarily separated; the preheated material is atomized through a sound wave atomizer and enters a film evaporation chamber, the pulse working frequency of the sound wave atomizer is 20-500 Hz, the film evaporation temperature is controlled to be 65-75 DEG C, and the pressure is controlled to be 100-1000 Pa; a temperature sensor arranged on the thin film evaporation surface transmits a real-time temperature signal to a control system of the sound wave atomizer, the real-time temperature signal is converted into a pulse signal, the working duty ratio D of the sound wave atomizer is controlled to change along with the temperature, and dynamic spraying liquid supply is carried out; and the thickness of the liquid film on the thin film evaporation surface is controlled to be 0.5-1mm. The raw materials are simple and easy to obtain, the operation is simple, the moisture in the TMAH pentahydrate crystal compound can be effectively removed, and the method is suitable for preparing the anhydrous TMAH organic solution in the electronic semiconductor industry.

Description

Technical Field

[0001] This invention relates to the dehydration of tetramethylammonium hydroxide pentahydrate, specifically to a dehydration apparatus and method for tetramethylammonium hydroxide pentahydrate crystals. The tetramethylammonium hydroxide obtained by this method is used in the manufacturing process of high-purity anhydrous semiconductor photoresist cleaning agents. Background Technology

[0002] Tetramethylammonium hydroxide (TMAH) is a strong organic base with high corrosiveness. It commonly exists as a pentahydrate crystalline powder, a colorless crystalline powder that is highly hygroscopic and deliquescent. It is a heat-sensitive substance, easily decomposing upon heating. Its melting point is 62–71°C, and its boiling point is 120°C. It completely decomposes and vaporizes at 135–145°C. TMAH is typically prepared as a 10% or 25% aqueous solution, which is colorless and transparent or slightly yellow. A 1% (wt) solution has a pH of 12.9. TMAH has wide applications in industry. As an organic synthesis reagent, it can react with various acids to prepare corresponding ammonium salts. Because TMAH is a quaternary ammonium base, it can be used as a surfactant. In catalysis, TMAH can be used as a catalyst. In analysis, TMAH is an excellent methylation solvent. In product purification, it is used as an ashless alkali to precipitate many metal elements. In the semiconductor field, TMAH is used as a major component of positive resist developers and photoresist stripping solutions.

[0003] TMAH is typically a 25% aqueous solution. Therefore, in photoresist cleaning solutions, adding one equivalent of tetramethylammonium hydroxide solution introduces three equivalents of water. However, the introduction of water significantly negatively impacts the stripping and cleaning effect. With increasing semiconductor chip packaging requirements and increasingly smaller chip manufacturing nodes, higher demands are placed on the performance of photoresist stripping solutions, with reducing the water content being a crucial aspect. Therefore, reducing the water content in TMAH solutions, preparing anhydrous TMAH organic solutions, and manufacturing highly efficient, low-corrosion photoresist stripping solutions to improve stripping and cleaning capabilities are of paramount importance.

[0004] The main production processes for TMAH include the silver oxide method, alkali replacement method, electrodialysis method, electrolysis method, and ion-exchange membrane electrolysis method. The TMAH aqueous solutions obtained by these methods are filtered, concentrated, crystallized, and dried to obtain a TMAH pentahydrate crystalline compound. In the TMAH pentahydrate crystalline compound, the water molecule content reaches 49.7 wt% of the total compound. When using TMAH·5H₂O to prepare photoresist stripping solution, a large amount of water is introduced. During the cleaning process, this water can cause a higher copper corrosion rate and affect the photoresist stripping effect. To further improve the cleaning effect of the photoresist stripping solution and manufacture chips that meet the current market manufacturing node size requirements, reducing the water content in the TMAH cleaning solution is crucial and has broad application prospects.

[0005] Russian patent RU2647845C1 discloses a method for preparing TMAH in a non-aqueous solution environment. This method employs a five-chamber, four-membrane electrodialysis process. Instead of an aqueous solution, a methanol solution of tetramethylammonium chloride is used as the raw material. The intermediate chamber uses a 0.2 wt% tetramethylammonium hydroxide methanol solution (water content ≤10%) instead of the traditional TMAH aqueous solution. Under the influence of an electric current, tetramethylammonium ions and hydroxide ions permeate through the ion exchange membrane into the intermediate chamber. Since the intermediate chamber is a methanol solution, a TMAH methanol solution is obtained. Initially, the TMAH methanol solution added to the intermediate chamber typically contains 10 wt% water. During electrodialysis, the TMAH concentration continuously increases, and although the water content decreases accordingly, the final product still contains a significant amount of water; therefore, the obtained TMAH still contains a considerable amount of water.

[0006] Chinese invention patent application CN104195560A discloses a method for preparing an anhydrous TMAH stripping solution. This anhydrous stripping solution is mainly composed of TMAH, propyl gallate, and an organic solvent mixed in a certain proportion, stirred under aeration for 30 minutes, and then filtered through 0.2μm filter paper. The TMAH anhydrous stripping solution prepared by this method has a very significant effect on removing dry etching residues from aluminum metal, and because it is an anhydrous formulation, it does not cause aluminum corrosion. However, TMAH itself contains five molecules of water of crystallization, resulting in a high water content in the prepared anhydrous stripping solution, which leads to a high corrosion rate for copper in semiconductor chips, failing to meet production requirements and requiring further improvement.

[0007] Taiwanese patent TWI486727B discloses a method for preparing and using an improved anhydrous stripping agent solution for removing photoresist from a substrate. This stripping agent solution contains dimethyl sulfoxide, tetramethylammonium hydroxide, and alkanolamine, a selectable auxiliary solvent, and less than about 3 wt% water. The stripping agent solution prepared by this method is easy to transport, has excellent loading capacity for the removed photoresist material, increases the solubility of the photoresist in the stripping solution, and has a low copper etching rate. This method uses TMAH·5H₂O as a raw material and reduces the water content in the prepared stripping agent solution by adding an organic solvent instead of water. However, each unit of TMAH added introduces an equal amount of water; therefore, this method does not provide a method for removing the water of crystallization from TMAH·5H₂O.

[0008] Chinese invention patent application CN114195655A discloses a method for dehydrating tetramethylammonium hydroxide pentahydrate crystals: Tetramethylammonium hydroxide crystals containing five molecules of crystallization are dissolved in an organic solvent to obtain a raw material solution of tetramethylammonium hydroxide organic solution; the raw material solution is preheated by primary distillation in a two-stage scraped-film molecular distillation apparatus before entering secondary distillation, with the temperature of the cold trap controlled at 0-8℃ and the pressure at 100-1000Pa, thereby controlling the evaporation flow rate of the secondary distillation raw material at 10-40 ml / (m³). 2 The molecular distillation process involves a temperature of 75-85℃ and a pressure of 100-1000 Pa. The heavy components are collected to obtain a tetramethylammonium hydroxide organic solution with a water content of 0.4-0.87 wt%. This invention's molecular distillation apparatus has strong separation capabilities, and the separated TMAH product can have a water content of less than 1%. However, its processing capacity is relatively small, and intermittent production cannot meet the needs of industrial production.

[0009] Chinese invention patent CN112752746B discloses a method for manufacturing an organic solution of quaternary ammonium hydroxide, employing a falling film evaporator. Preferably, water is separated from the organic solution of quaternary ammonium hydroxide at 600 Pa and 60-140℃ to obtain an organic solution with a water content of less than 1 wt%. This technology uses a traditional scraped film or falling film evaporator where the material forms a liquid film under gravity or scraper action. However, due to changes in liquid surface tension, viscosity (such as concentration increase during dehydration), and equipment processing precision, the liquid film is prone to uneven thickness. Thinner areas will evaporate first, and the unevenness and drying of the liquid film directly lead to unstable overall heat transfer coefficients that decrease with operating time. Once a dried-out or scale layer forms, thermal resistance increases significantly. For TMAH dehydration, a process accompanied by concentration changes, the retained material may become over-concentrated, crystallize, or decompose, resulting in decreased product purity and the potential generation of impurities such as trimethylamine, affecting its application in the electronics industry (e.g., in developing solutions), product purity, and yield. Summary of the Invention

[0010] To address the shortcomings of existing technologies, the present invention aims to provide a method for dehydrating tetramethylammonium hydroxide pentahydrate crystals using an internal circulation thin-film evaporation device based on dynamic liquid supply and process control under low temperature and high pressure conditions. This method is simple to operate, effectively removes moisture from TMAH·5H2O, and effectively prevents TMAH from reabsorbing moisture; the resulting tetramethylammonium hydroxide organic solution has a water content of 0.15-0.48 wt%, which can be used in the manufacturing process of high-purity anhydrous semiconductor photoresist cleaning agents.

[0011] The objective of this invention is achieved through the following technical solution:

[0012] A thin-film evaporation device for dehydrating tetramethylammonium hydroxide pentahydrate crystals based on dynamic liquid supply includes a thin-film evaporator, an acoustic atomizer, an evaporation chamber, and a cold trap. The acoustic atomizer is located at the inlet of the thin-film evaporation chamber of the thin-film evaporator and is connected to the evaporation chamber via a pipe. The outer periphery of the thin-film evaporator is a thin-film evaporation surface, on which a temperature sensor is installed. The temperature sensor is connected to the control system of the acoustic atomizer. The cold trap is connected to the light component distillation range pipeline of the thin-film evaporator. The lower end of the thin-film evaporator is connected to the acoustic atomizer via a pipe, and an internal circulation pump is installed on the pipe. A product collection device is installed at the lower end of the thin-film evaporator, and a light component collection device is installed at the lower end of the cold trap. The cold trap is also connected to a constant-temperature water bath and a vacuum pump. The thin-film evaporator is also connected to a vacuum pump and a constant-temperature oil bath. The evaporation chamber is also connected to a vacuum pump and a constant-temperature water bath.

[0013] To further achieve the purpose of the present invention, preferably, the second constant temperature water bath device is connected to the cold trap through a cooling water inlet and a cooling water outlet, and the cold trap is connected to the second vacuum pump.

[0014] Preferably, the upper end of the thin-film evaporator is connected to a constant-temperature oil bath via a heat-conducting oil pipeline.

[0015] Preferably, the evaporation chamber is connected to the first constant temperature water bath device; the first vacuum pump is connected to the thin film evaporator and the evaporation chamber through pipes respectively.

[0016] A method for dehydrating tetramethylammonium hydroxide pentahydrate crystals using dynamic liquid supply based on thin-film evaporation using the aforementioned device: Tetramethylammonium hydroxide crystals containing five molecules of water of crystallization are dissolved in an organic solvent to obtain a tetramethylammonium hydroxide organic solution raw material; the raw material is preheated and preliminarily separated in an evaporation chamber; the preheated material is atomized by an acoustic atomizer and enters the thin-film evaporation chamber, with the pulse operating frequency of the acoustic atomizer being 20Hz-500Hz, controlling the temperature of the thin-film evaporation at 65-75℃ and the pressure at 100-1000Pa; a temperature sensor installed on the thin-film evaporation surface transmits the real-time temperature signal to the control system of the acoustic atomizer, converting it into a pulse signal to control the duty cycle D of the acoustic atomizer to change with temperature, performing dynamic spray liquid supply; thus controlling the liquid film thickness on the thin-film evaporation surface to be 0.5-1mm.

[0017] Preferably, the sonic atomizer's duty cycle D is dynamically adjusted according to temperature for liquid supply. During the preheating and start-up phase, when the detected temperature T < 60℃, the sonic atomizer operates at its lowest duty cycle D0. When the detected temperature T is between 60℃ and 68℃, the sonic atomizer's duty cycle D linearly increases from the lowest duty cycle D0 to the highest duty cycle Dopt, satisfying the relationship: D = D0 + K1 * (T - 60), where K1 is the heating gain coefficient. When the detected temperature T is between 68℃ and 74℃, the duty cycle D is maintained at the highest duty cycle Dopt. When the detected temperature T > 74℃, the duty cycle D linearly decreases from Dopt, satisfying the relationship: D = Dopt - K2 * (T - 74), where K2 is the protection attenuation coefficient, and K2 > K1. If the detected temperature of the film evaporation surface reaches 78℃, the sonic atomizer is fully activated for rapid cooling.

[0018] Preferably, the minimum duty cycle D0 is 5%-15%; the Dot is 40-70%; the heating gain coefficient K1 is 5% / ℃-15% / ℃; and the protection attenuation coefficient K2 is 20% / ℃-40% / ℃.

[0019] Preferably, the preheating temperature of the evaporation chamber is 40-50℃ and the pressure is 0.01-0.02 MPa.

[0020] Preferably, during the preheating and start-up phase, the product collection device is turned off, the internal circulation pump is turned on, and the recombinant liquid is pumped back into the feed pipeline via the internal circulation pump and enters the sonic atomizer, where it is separated again on the thin film evaporator. After the preheating and start-up phase is completed, the internal circulation pump is turned off and product collection begins.

[0021] Preferably, the organic solvent is DMSO, 1,2-propanediol, or ethylene glycol; the concentration of tetramethylammonium hydroxide after dehydration of the tetramethylammonium hydroxide organic solution is 10-15 wt%.

[0022] Compared with the prior art, the method of the present invention has the following advantages and beneficial effects:

[0023] 1) This invention uses an acoustic atomizer installed at the feed inlet of a thin-film evaporator. The raw material liquid is controlled by the acoustic atomizer control system, which can effectively and stably form a uniform liquid film of 0.5-1mm and maintain the uniformity of the liquid film on the thin-film evaporation surface. This eliminates the need for the existing thin-film evaporator scraping device and avoids the problems of excessively thick liquid film and dry areas on the evaporation surface caused by scraping. It also avoids the problems of large changes in liquid film thickness caused by feed fluctuations in existing thin-film evaporation technology, which can lead to local dryness or excessively thick liquid film on the thin-film evaporation surface.

[0024] 2) The tetramethylammonium hydroxide organic solution obtained by this invention has a water content of 0.15-0.48 wt%, and the tetramethylammonium hydroxide can be used in the manufacturing process of high-purity anhydrous semiconductor photoresist cleaning agent.

[0025] 3) Under the high vacuum conditions of the thin-film evaporator, the present invention greatly reduces the heating temperature required for the dehydration of TMAH organic solution, thus avoiding the thermal decomposition of TMAH.

[0026] 4) TMAH is hygroscopic. Dissolving TMAH in organic solvents such as propylene glycol and ethylene glycol can effectively prevent it from absorbing moisture from the air, and it is not easily decomposed and is easy to store. Attached Figure Description

[0027] Figure 1 A diagram of an internal circulation thin-film evaporator for dynamic liquid supply process control.

[0028] The figure shows: 1-First constant temperature water bath device, 2-Evaporation chamber, 3-Constant temperature oil bath device, 4-Thin film evaporation chamber, 5-Sonic atomizer, 6-Thin film evaporation surface, 7-Temperature sensor, 8-Internal circulation pump, 9-First vacuum pump, 10-Second constant temperature water bath device, 11-Cold trap, 12-Second vacuum pump, 13-Thin film evaporator, 14-Cooling water inlet, 15-Cooling water outlet, 16-Product collection device, 17-Light component collection device. Detailed Implementation

[0029] To better understand the present invention, it will be further described below with reference to the accompanying drawings and specific embodiments. However, the implementation of the present invention is not limited thereto. The described embodiments are some, but not all, of the embodiments of the present invention. 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.

[0030] In the description of this invention, it should be noted that the terms "upper end," "lower end," "entrance," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] Because TMAH is highly hygroscopic and readily absorbs moisture from the air, the resulting solid TMAH obtained after drying the pentahydrate crystalline compound is difficult to preserve. According to literature, heating solid TMAH hydrate does not yield anhydrous compounds. TMAH is a heat-sensitive substance and decomposes easily upon heating. If traditional evaporation methods are used to dehydrate the TMAH solution, it will decompose during the dehydration process. Therefore, distillation and traditional evaporation methods cannot be used to prepare anhydrous TMAH solutions. In traditional falling film evaporation equipment, due to changes in liquid surface tension, viscosity (such as increased concentration during dehydration), and the precision of equipment manufacturing, uneven liquid film thickness is highly likely. Thinner areas will evaporate first, and dried-out areas mean a sharp decrease in heat transfer efficiency. Simultaneously, the material (especially organic bases like TMAH) may experience localized overheating and coking on the heating wall, leading to product decomposition, spoilage, and contamination of the heat transfer surface. The unevenness and drying of the liquid film directly result in an unstable overall heat transfer coefficient that decreases over time. Once a dry or scaled layer forms, the thermal resistance increases significantly. To maintain the evaporation rate, the temperature of the heating medium must be continuously increased, which further exacerbates the risk of thermal degradation of TMAH, creating a vicious cycle. Evaporators with scraped or falling film coatings also easily result in uneven liquid film thickness, significantly increasing thermal resistance and affecting product purity.

[0033] This invention discovers that using an acoustic atomizer in conjunction with a thin-film evaporator can effectively solve the problems of existing technologies. It should be noted that in existing technologies, acoustic atomizers are generally used in respiratory disease treatment, home humidification / landscape design, beauty and skincare, industrial humidification / spraying, agricultural irrigation / insect control, and environmental purification. Specific applications include medical atomization therapy, industrial precision spraying, agricultural greenhouse humidification, and home aromatherapy humidification. These devices mainly consist of an atomizing head, a power module, and a control system. Their working mode involves breaking the liquid flow into fine droplets. This principle can also be applied to acoustic atomizers in traditional flash evaporation devices. The acoustic atomizer breaks the high-pressure feed liquid flow into countless fine droplets, thus creating favorable conditions for efficient flash evaporation. This increases the total surface area of ​​the liquid, allowing for rapid and uniform vaporization. Simultaneously, the fine atomization effectively suppresses the entrainment of large droplets in the steam, improving steam quality.

[0034] However, this invention further discovers, based on the existing technology of ultrasonic atomizers that break the feed liquid flow into fine droplets, that by placing the ultrasonic atomizer at the feed inlet of the thin-film evaporator, and controlling the feed liquid through the ultrasonic atomizer control system, a uniform liquid film of 0.5-1 mm can be effectively and stably formed, and the uniformity of the liquid film on the thin-film evaporation surface can be maintained. This eliminates the need for the existing thin-film evaporator scraping device, and avoids the problems of excessively thick liquid film and dry areas on the evaporation surface caused by scraping. It also avoids the problems of large variations in liquid film thickness caused by feed fluctuations in existing thin-film evaporation technology, resulting in local dryness or excessively thick liquid film on the thin-film evaporation surface. This invention mainly utilizes the ultrasonic atomizer to break the feed liquid flow into fine droplets and spray them into the evaporation chamber cavity, while uniformly and efficiently spraying the feed liquid onto the thin-film evaporation surface. At the same time, a temperature sensor feeds back the temperature signal to the ultrasonic atomizer control system, forming a pulse control signal to control the spray intensity and cycle time of the ultrasonic atomizer, so as to stably form a uniform liquid film of 0.5-1 mm on the thin-film evaporation surface. The uniformity and stability of the liquid film thickness are very important factors for the evaporation efficiency and effect of thin film.

[0035] like Figure 1 As shown, the thin-film evaporation device for dehydrating tetramethylammonium hydroxide pentahydrate crystals based on dynamic liquid supply includes a thin-film evaporator 13, an acoustic atomizer 5, an evaporation chamber 2, and a cold trap 11. The acoustic atomizer 5 is located at the inlet of the thin-film evaporation chamber 4 of the thin-film evaporator 13 and is connected to the evaporation chamber 2 via a pipe. The outer periphery of the thin-film evaporation chamber 4 is a thin-film evaporation surface 6, and a temperature sensor 7 is installed on the thin-film evaporation surface 6. The temperature sensor 7 is connected to the control system of the acoustic atomizer 5. The cold trap 11 is connected to the light component distillation range pipeline of the thin-film evaporator 13. The lower end of the thin-film evaporator 13 is connected to the acoustic atomizer 5 via a pipe, and an internal circulation pump 8 is installed on the pipe. A product collection device 16 is installed at the lower end of the thin-film evaporator 13, and a light component collection device 17 is installed at the lower end of the cold trap 11. The cold trap 11 is also connected to a constant temperature water bath and a vacuum pump. The thin-film evaporator 13 is also connected to a vacuum pump and a constant temperature oil bath. The evaporation chamber 2 is also connected to a vacuum pump and a constant temperature water bath. Specifically, the second constant temperature water bath device 10 is connected to the cold trap 11 through the cooling water inlet 14 and the cooling water outlet 15, respectively, and the cold trap 11 is connected to the second vacuum pump 12; the upper end of the thin film evaporator 13 is connected to the constant temperature oil bath 3 through the heat transfer oil pipeline; the evaporation chamber 2 is connected to the first constant temperature water bath device 1; and the first vacuum pump 9 is connected to the thin film evaporator 13 and the evaporation chamber 2 through pipelines.

[0036] Specifically, Figure 1In the process, evaporation chamber 2 is connected to an acoustic atomizer 5 located at the feed inlet of the thin-film evaporator via a pipe; evaporation chamber 2 is connected to a first constant-temperature water bath device 1, which controls the temperature of evaporation chamber 2, and the material is preheated in evaporation chamber 2; the material is sprayed into the cavity of thin-film evaporation chamber 4 through acoustic atomizer 5, the outer periphery of thin-film evaporation chamber 4 is a thin-film evaporation surface 6, and a temperature sensor 7 is installed on the thin-film evaporation surface 6, which is connected to the control system of acoustic atomizer 5; the upper end of thin-film evaporator 13 is connected to a constant-temperature oil bath 3 via a heat transfer oil pipeline, and the heating temperature of thin-film evaporator 13 is adjusted and controlled by the constant-temperature oil bath 3, and the material is heated and efficiently separated into vapor and liquid phases in thin-film evaporation chamber 4; a product collection device 16 is provided at the lower end of thin-film evaporator 13; a cold trap 11 is connected to the light component distillation section pipeline of thin-film evaporator 13, and the cold trap 11... The cold trap 11 cools the distilled light components, and a light component collection device 17 is provided at the lower end of the cold trap 11. The second constant temperature water bath device 10 is connected to the cold trap 11 through the cooling water inlet 14 and the cooling water outlet 15, respectively. The cooling temperature of the cold trap is controlled by the second constant temperature water bath device 10. The cold trap 11 is also connected to the second vacuum pump 12, which controls the pressure of the cold trap 11. The first vacuum pump 9 is connected to the thin film evaporator 13 and the evaporation chamber 2 through pipes, respectively. The pressure of the evaporation chamber 2 and the thin film evaporation chamber 4 is controlled by the first vacuum pump 9. The lower end of the thin film evaporator 13 is connected to the sonic atomizer 5 through a pipe. An internal circulation pump 8 is provided on the pipe. When the product collection valve of the product collection device 16 is closed, the material is transported to the feed pipeline by the internal circulation pump 8 when the internal circulation system is turned on. The feed pipeline is connected to the sonic atomizer 5.

[0037] A 3-5 wt% tetramethylammonium hydroxide organic solution is fed into the evaporator 1 through a first constant-temperature water bath device 1, maintaining the temperature at 25-30°C. The solution then enters the evaporation chamber 2 for preheating via negative pressure adsorption by a first vacuum pump 9. The first-stage evaporation preheating temperature in the evaporation chamber is controlled at 40-50°C, and the pressure is 0.01-0.02 MPa. The preheated material is atomized and sprayed into the thin-film evaporation chamber 4 through an acoustic atomizer 5 installed at the feed inlet of the thin-film evaporator 13. The temperature of the cold trap 11 is controlled at 0-8°C by a second constant-temperature water bath device 10. The pressure of the cold trap 11 is controlled to be 100-1000 Pa by the second vacuum pump 12, and the pressure of the thin film evaporation chamber 4 is controlled to be 100-1000 Pa by the first vacuum pump 9. The thin film evaporation surface 6 is heated by the constant temperature hot oil bath 3, with a temperature of about 65-75℃. The temperature sensor 7 set on the thin film evaporation surface 6 transmits the real-time temperature signal to the control system of the sonic atomizer, which converts it into a pulse signal to control the working duty cycle D of the sonic atomizer to change with the temperature, so as to perform dynamic spray liquid supply; so that the liquid film thickness on the thin film evaporation surface is controlled to be 0.5-1 mm. Specifically, the ultrasonic atomizer's duty cycle D is dynamically controlled to supply liquid spray as the temperature changes. During the preheating and start-up phase, when the detected temperature T < 60℃, the ultrasonic atomizer operates at the lowest duty cycle D0. When the detected temperature T is between 60℃ and 68℃, the ultrasonic atomizer's duty cycle D linearly increases from the lowest duty cycle D0 to the highest duty cycle Dopt, satisfying the relationship: D = D0 + K1 * (T - 60), where K1 is the heating gain coefficient. When the detected temperature T is between 68℃ and 74℃, the duty cycle D is maintained at the highest duty cycle Dopt. When the detected temperature T > 74℃, the duty cycle D linearly decreases from Dopt, satisfying the relationship: D = Dopt - K2 * (T - 74), where K2 is the protection attenuation coefficient, and K2 > K1. If the detected temperature of the film evaporation surface reaches 78℃, the ultrasonic atomizer is fully turned on for rapid cooling. The minimum duty cycle D0 is 5%-15%; Dot is 40-70%; the heating gain coefficient K1 is 5% / ℃-15% / ℃; and the protection attenuation coefficient K2 is 20% / ℃-40% / ℃. During the preheating start-up phase, the product collection device 16 is closed, and the internal circulation pump 8 is turned on. The recombinant liquid is pumped back into the feed line via the internal circulation pump and enters the acoustic atomizer 5, where it is separated again on the thin-film evaporator. After the preheating start-up phase ends, the internal circulation pump is turned off, and product collection begins.

[0038] The second constant temperature water bath device 10 is connected to the condenser plate inside the thin film evaporator cylinder 13 through a cooling water inlet and a cooling water outlet to control the condensation temperature. The light components (water and some organic solvents) generated by thin film evaporation are condensed on the condenser plate and discharged from the light component outlet to the light component collection tank 17. The heavy components (tetramethylammonium hydroxide) are discharged from the heavy component outlet to the product collection tank 16. By opening or closing the cold trap cooling water inlet valve 14 and the cold trap cooling water outlet valve 15, the cold trap 11 is controlled to enhance the condensation. Uncondensed steam enters the cold trap 11 along the pipe and condenses inside the cold trap due to the further decrease in temperature, preventing steam from entering the second vacuum pump 12.

[0039] For the dehydration method of tetramethylammonium hydroxide pentahydrate crystals of the present invention, a vacuum pump creates a negative pressure inside the evaporator. This negative pressure forces the raw material through the feed inlet into the primary evaporator for preheating. During preheating, some water is removed, reducing the operating load of the thin-film molecular evaporation system. The preheated raw material is then controlled by a valve to enter the thin-film evaporator, where the lighter components evaporate on the heating surface. Since molecules of different substances travel different distances after escaping from the liquid surface, the gas molecules of the lighter components (water and some organic solvents) have a larger mean free path, reaching the condenser plate and being condensed, exiting at the lighter component outlet. The heavier components (TMAH) do not reach the condenser plate and are discharged along the mixture at the heavier component outlet.

[0040] Example 1

[0041] First, the TMAH pentahydrate crystalline compound was dissolved in ethylene glycol (EG) solution. The mixture was stirred at room temperature until the TMAH crystals were completely dissolved, resulting in a 500 ml TMAH ethylene glycol solution. The TMAH content was measured to be 3.0% and the water content to be 4.17%.

[0042] A 3.0 wt% tetramethylammonium hydroxide organic solution is fed into the inlet and maintained at 25°C by a first constant-temperature water bath device 1. The tetramethylammonium hydroxide organic solution enters the evaporation chamber 2 for preheating treatment through the negative pressure adsorption of the first vacuum pump 9. The preheating temperature of the first-stage evaporation is controlled at 40°C, and the pressure of the evaporation chamber is 0.02 MPa. The preheated material is atomized by the sonic atomizer 5 and enters the thin-film evaporation chamber 4. The temperature of the cold trap 11 is controlled at 5°C by the second constant-temperature water bath device 10, and the pressure of the cold trap 11 is controlled at 500 Pa by the second vacuum pump 12. The pressure of the thin-film evaporation chamber 4 is controlled at 500 Pa by the first vacuum pump 9. The thin-film evaporation surface 6 is heated by a constant-temperature hot oil bath 3 at a temperature of approximately 65-75°C. The temperature sensor 7 installed on the thin-film evaporation surface transmits the real-time temperature signal to the control system of the sonic atomizer, which converts it into a pulse signal to control the sonic atomizer 5 to dynamically supply liquid. The acoustic atomizer 5 operates at a pulse frequency of 20Hz-500Hz. Through a power module and atomizing head, it breaks down materials into micron-sized droplet clouds, which are then uniformly sprayed onto the thin-film evaporation surface 6. The control system uses feedback temperature signals and pulse frequency to control the spray volume and mode. Specifically, during the preheating and start-up phase, when the detected temperature T < 60℃, the acoustic atomizer operates at its lowest duty cycle D0, which is 10%. During the linear heating phase, when the detected temperature T enters the range of 60℃ to 68℃, the acoustic atomizer's duty cycle D increases linearly from the lowest duty cycle D0 to the highest duty cycle Dopt as the temperature rises, satisfying the relationship: D = D0 + K1*(T -60), where K1 is the heating gain coefficient, with a value of 12.5% / ℃; during the steady-state evaporation stage, when the detected temperature T is within the target evaporation range of 68℃ to 74℃, the working duty cycle D is controlled to maintain at the highest duty cycle Dopt, with a value of 50%, to achieve efficient and gentle evaporation; during the overheat protection stage, when the detected temperature T>74℃, the working duty cycle D decreases linearly from Dopt, satisfying the relationship: D=Dopt-K2*(T-74), where K2 is the protection attenuation coefficient, and K2>K1, with a value of 30% / ℃; if the temperature of the detected film evaporation surface 6 reaches 78℃, the acoustic atomizer is fully turned on for rapid cooling. Through the dynamic control of the acoustic atomizer 5 control system, the liquid supply rate and evaporation rate are kept in dynamic balance, and the liquid film thickness is controlled at the ideal 0.5-1mm.

[0043] In this embodiment, the internal circulation mode works as follows: During the preheating and start-up phase, the product collection device 16 is closed, and the internal circulation pump 8 is turned on. The recombinant material is pumped back into the feed pipeline via the internal circulation pump 8 and enters the acoustic atomizer 5, where it is separated again on the thin-film evaporator. After the preheating and start-up phase, the internal circulation pump 8 is turned off, and product collection begins. This thin-film evaporation equipment is used to separate the TMAH pentahydrate crystal compound. The inlet valve 14 and outlet valve 15 of the cooling water pipeline of the cold trap are opened, and the temperature of the cold trap is controlled at 5°C and the pressure at 500 Pa.

[0044] The invention incorporates a dynamic liquid supply-based acoustic atomizer 5, which uses a hot wall surface temperature sensor 7 to collect the hot wall surface temperature and feeds back temperature pulse signals to the acoustic atomizer. This dynamically controls the atomizer's spray, ensuring the thickness of the liquid film and the heat transfer efficiency on the thin-film evaporation surface 6. The efficient evaporation mode, combined with the internal circulation mode of this invention, improves the water removal effect of the TMAH system. In this embodiment, the feed rate is 0.45 ml / s; the composition of the collected heavy components after evaporation is analyzed, revealing a TMAH mass concentration of 11.7% and a water content of 0.48%.

[0045] Example 2

[0046] First, the TMAH pentahydrate crystalline compound was dissolved in propylene glycol (PG) solution and stirred at room temperature until the TMAH crystals were completely dissolved, yielding 500 ml of TMAH propylene glycol solution. The TMAH content was measured to be 2.7% and the water content to be 3.46%.

[0047] A 2.7 wt% tetramethylammonium hydroxide organic solution is fed into the inlet through a first constant-temperature water bath device 1, maintaining the temperature at 25°C. The tetramethylammonium hydroxide organic solution enters the evaporation chamber 2 for preheating treatment through the negative pressure adsorption of the first vacuum pump 9. The preheating temperature of the first-stage evaporation is controlled at 45°C, and the pressure of the evaporation chamber is 0.015 MPa. The preheated material is atomized by the sonic atomizer 5 and enters the thin-film evaporation chamber 4. The temperature of the cold trap 11 is controlled at 5-8°C by the second constant-temperature water bath device 10, and the pressure of the cold trap 11 is controlled at approximately 1000 Pa by the second vacuum pump 12. The pressure of the thin-film evaporation chamber 4 is controlled at 1000 Pa by the first vacuum pump 9. The thin-film evaporation surface 6 is heated by a constant-temperature hot oil bath 3, with a temperature of approximately 65-75°C. The temperature sensor 7 installed on the thin-film evaporation surface transmits the real-time temperature signal to the control system of the sonic atomizer, which converts it into a pulse signal to control the sonic atomizer 5 to dynamically supply liquid. The acoustic atomizer 5 operates at a pulse frequency of 20Hz-500Hz. Through a power module and atomizing head, it breaks down materials into micron-sized droplet clouds, which are then uniformly sprayed onto the thin-film evaporation surface 6. The control system uses feedback temperature signals and pulse frequency to control the spray volume and mode. Specifically, during the preheating and start-up phase, when the detected temperature T < 60℃, the acoustic atomizer operates at its lowest duty cycle D0, which is 10%. During the linear heating phase, when the detected temperature T enters the range of 60℃ to 68℃, the acoustic atomizer's duty cycle D increases linearly from the lowest duty cycle D0 to the highest duty cycle Dopt as the temperature rises, satisfying the relationship: D = D0 + K1*(T -60), where K1 is the heating gain coefficient, with a value of 12.5% / ℃; during the steady-state evaporation stage, when the detected temperature T is within the target evaporation range of 68℃ to 74℃, the working duty cycle D is controlled to maintain at the highest duty cycle Dopt, with a value of 50%, to achieve efficient and gentle evaporation; during the overheat protection stage, when the detected temperature T>74℃, the working duty cycle D decreases linearly from Dopt, satisfying the relationship: D=Dopt-K2*(T-74), where K2 is the protection attenuation coefficient, and K2>K1, with a value of 30% / ℃; if the temperature of the detected film evaporation surface 6 reaches 78℃, the acoustic atomizer is fully turned on for rapid cooling. Through the dynamic control of the acoustic atomizer 5 control system, the liquid supply rate and evaporation rate are kept in dynamic balance, and the liquid film thickness is controlled at the ideal 0.5-1mm.

[0048] In this embodiment, the internal circulation mode works as follows: During the preheating and start-up phase, the product collection device 16 is closed, and the internal circulation pump 8 is turned on. The recombinant material is pumped back into the feed pipeline via the internal circulation pump 8 and enters the acoustic atomizer 5, where it is separated again on the thin-film evaporator. After the preheating and start-up phase, the internal circulation pump 8 is turned off, and product collection begins. This thin-film evaporation equipment is used to separate the TMAH pentahydrate crystal compound. The inlet valve 14 and outlet valve 15 of the cooling water pipeline of the cold trap are opened, and the temperature of the cold trap is controlled at 5°C and the pressure at 500 Pa.

[0049] The invention incorporates a dynamic liquid supply-based acoustic atomizer 5, which uses a hot wall surface temperature sensor 7 to collect the hot wall surface temperature and feeds back temperature pulse signals to the acoustic atomizer. This dynamically controls the atomizer's spray, ensuring the thickness of the liquid film and the heat transfer efficiency on the thin-film evaporation surface 6. The efficient evaporation mode, combined with the internal circulation mode of this invention, improves the water removal effect of the TMAH system. In this embodiment, the feed rate is 0.45 ml / s. Composition analysis of the collected heavy components after evaporation revealed a TMAH mass concentration of 13.1% and a water content of 0.32%.

[0050] Example 3

[0051] First, the TMAH pentahydrate crystalline compound was dissolved in propylene glycol (PG) solution and stirred at room temperature until the TMAH crystals were completely dissolved, yielding 500 ml of TMAH propylene glycol solution. The TMAH content was measured to be 3.9% and the water content to be 5.82%.

[0052] A 3.9 wt% tetramethylammonium hydroxide organic solution is fed into the inlet and maintained at 25°C by a first constant-temperature water bath device 1. The tetramethylammonium hydroxide organic solution enters the evaporation chamber 2 for preheating treatment through the negative pressure adsorption of the first vacuum pump 9. The preheating temperature of the first-stage evaporation is controlled at 50°C and the pressure of the evaporation chamber is 0.01 MPa. The preheated material is atomized by an acoustic atomizer 5 and enters the thin-film evaporation chamber 4. The temperature of the cold trap 11 is controlled at 5°C by a second constant-temperature water bath device 10, and the pressure of the cold trap 11 is controlled at 250 Pa by a second vacuum pump 12. The pressure of the thin-film evaporation chamber 4 is controlled at 250 Pa by the first vacuum pump 9. The thin-film evaporation surface 6 is heated by a constant-temperature hot oil bath 3 at a temperature of approximately 65-75°C. The temperature sensor 7, located on the thin-film evaporation surface, transmits the real-time temperature signal to the control system of the acoustic atomizer, which converts it into a pulse signal to control the acoustic atomizer 5 for dynamic liquid supply. The acoustic atomizer 5 operates at a pulse frequency of 20Hz-500Hz. Through a power module and atomizing head, it breaks down materials into micron-sized droplet clouds, which are then uniformly sprayed onto the thin-film evaporation surface 6. The control system uses feedback temperature signals and pulse frequency to control the spray volume and mode. Specifically, during the preheating and start-up phase, when the detected temperature T < 60℃, the acoustic atomizer operates at its lowest duty cycle D0, which is 10%. During the linear heating phase, when the detected temperature T enters the range of 60℃ to 68℃, the acoustic atomizer's duty cycle D increases linearly from the lowest duty cycle D0 to the highest duty cycle Dopt as the temperature rises, satisfying the relationship: D = D0 + K1*(T -60), where K1 is the heating gain coefficient, with a value of 12.5% / ℃; during the steady-state evaporation stage, when the detected temperature T is within the target evaporation range of 68℃ to 74℃, the working duty cycle D is controlled to maintain at the highest duty cycle Dopt, with a value of 50%, to achieve efficient and gentle evaporation; during the overheat protection stage, when the detected temperature T>74℃, the working duty cycle D decreases linearly from Dopt, satisfying the relationship: D=Dopt-K2*(T-74), where K2 is the protection attenuation coefficient, and K2>K1, with a value of 30% / ℃; if the temperature of the detected film evaporation surface 6 reaches 78℃, the acoustic atomizer is fully turned on for rapid cooling. Through the dynamic control of the acoustic atomizer 5 control system, the liquid supply rate and evaporation rate are kept in dynamic balance, and the liquid film thickness is controlled at the ideal 0.5-1mm.

[0053] In this embodiment, the internal circulation mode works as follows: During the preheating and start-up phase, the product collection device 16 is closed, and the internal circulation pump 8 is turned on. The recombinant material is pumped back into the feed pipeline via the internal circulation pump 8 and enters the acoustic atomizer 5, where it is separated again on the thin-film evaporator. After the preheating and start-up phase, the internal circulation pump 8 is turned off, and product collection begins. This thin-film evaporation equipment is used to separate the TMAH pentahydrate crystal compound. The inlet valve 14 and outlet valve 15 of the cooling water pipeline of the cold trap are opened, and the temperature of the cold trap is controlled at 5°C and the pressure at 500 Pa.

[0054] The invention incorporates a dynamic liquid supply-based acoustic atomizer 5, which uses a hot wall surface temperature sensor 7 to collect the hot wall surface temperature and feeds back temperature pulse signals to the acoustic atomizer. This dynamically controls the atomizer's spray, ensuring the thickness of the liquid film and the heat transfer efficiency on the thin-film evaporation surface 6. The efficient evaporation mode, combined with the internal circulation mode of this invention, improves the water removal effect of the TMAH system. In this embodiment, the feed rate is 0.45 ml / s. Composition analysis of the collected heavy components after evaporation revealed a TMAH mass concentration of 14.8% and a water content of 0.23%.

[0055] Example 4

[0056] First, the TMAH pentahydrate crystalline compound was dissolved in propylene glycol (PG) solution. The mixture was stirred at room temperature until the TMAH crystals were completely dissolved, resulting in a 500 ml TMAH propylene glycol solution. The TMAH content was measured to be 3.1% and the water content to be 4.41%.

[0057] A 3.1 wt% tetramethylammonium hydroxide organic solution is fed into the inlet and maintained at 25°C by a first constant-temperature water bath device 1. The tetramethylammonium hydroxide organic solution enters the evaporation chamber 2 for preheating treatment through the negative pressure adsorption of the first vacuum pump 9. The preheating temperature of the first-stage evaporation is controlled at 50°C, and the pressure of the evaporation chamber is 0.01 MPa. The preheated material is atomized by an acoustic atomizer 5 and enters the thin-film evaporation chamber 4. The temperature of the cold trap 11 is controlled at 5-8°C by a second constant-temperature water bath device 10, and the pressure of the cold trap 11 is controlled at 100 Pa by a second vacuum pump 12. The pressure of the thin-film evaporation chamber 4 is controlled at 100 Pa by the first vacuum pump 9. The thin-film evaporation surface 6 is heated by a constant-temperature hot oil bath 3 at a temperature of approximately 65-75°C. The temperature sensor 7 installed on the thin-film evaporation surface transmits the real-time temperature signal to the control system of the acoustic atomizer, which converts it into a pulse signal to control the acoustic atomizer 5 to dynamically supply liquid. The acoustic atomizer 5 operates at a pulse frequency of 20Hz-500Hz. Through a power module and atomizing head, it breaks down materials into micron-sized droplet clouds, which are then uniformly sprayed onto the thin-film evaporation surface 6. The control system uses feedback temperature signals and pulse frequency to control the spray volume and method. Specifically, during the preheating and start-up phase, when the detected temperature T < 65℃, the acoustic atomizer operates at its lowest duty cycle D0, which is 10%. During the linear heating phase, when the detected temperature T enters the range of 65℃ to 73℃, the acoustic atomizer's duty cycle D increases linearly from the lowest duty cycle D0 to the highest duty cycle Dopt as the temperature rises, satisfying the relationship: D = D0 + K1*(T -60), where K1 is the heating gain coefficient, with a value of 12.5% / ℃; during the steady-state evaporation stage, when the detected temperature T is in the target evaporation range of 73℃ to 79℃, the working duty cycle D is controlled to maintain at the highest duty cycle Dopt, with a value of 50%, to achieve efficient and gentle evaporation; during the overheat protection stage, when the detected temperature T>74℃, the working duty cycle D decreases linearly from Dopt, satisfying the relationship: D=Dopt-K2*(T-74), where K2 is the protection attenuation coefficient, and K2>K1, with a value of 30% / ℃; if the temperature of the detected film evaporation surface 6 reaches 83℃, the acoustic atomizer is fully turned on for rapid cooling. Through the dynamic control of the acoustic atomizer 5 control system, the liquid supply rate and evaporation rate are kept in dynamic balance, and the liquid film thickness is controlled at the ideal 0.5-1mm.

[0058] In this embodiment, the internal circulation mode works as follows: During the preheating and start-up phase, the product collection device 16 is closed, and the internal circulation pump 8 is turned on. The recombinant liquid is pumped back into the feed pipe via the internal circulation pump 8 and enters the acoustic atomizer 5, where it is separated again on the thin-film evaporator. After the preheating and start-up phase, the internal circulation pump 8 is turned off, and product collection begins. This thin-film evaporation equipment is used to separate the TMAH pentahydrate crystal compound. The inlet valve 14 and outlet valve 15 of the cooling water pipe of the cold trap are opened, and the temperature of the cold trap is controlled at 5°C and the pressure at 100 Pa.

[0059] The invention incorporates a dynamic liquid supply-based acoustic atomizer 5, which uses a hot wall surface temperature sensor 7 to collect the hot wall surface temperature and feeds back temperature pulse signals to the acoustic atomizer. This dynamically controls the atomizer's spray, ensuring the thickness of the liquid film and the heat transfer efficiency on the thin-film evaporation surface 6. The efficient evaporation mode, combined with the internal circulation mode of this invention, improves the water removal effect of the TMAH system. In this embodiment, the feed rate is 0.45 ml / s. Composition analysis of the collected heavy components after evaporation revealed a TMAH mass concentration of 14.2% and a water content of 0.15%.

[0060] Comparative Example 1

[0061] First, the TMAH pentahydrate crystalline compound was dissolved in dimethyl sulfoxide (DMSO) solution, a small amount of water was added, and the mixture was stirred at room temperature until the TMAH crystals were completely dissolved, thus obtaining 500 ml of TMAH dimethyl sulfoxide solution. The TMAH content was measured to be 3.7% and the water content to be 9.84%.

[0062] The evaporation chamber was preheated at 45℃ and pressure at 0.02 MPa. The thin-film evaporation temperature was 75℃ and pressure at 1000 Pa, with a feed rate of 0.4 ml / s. The heavy components collected after evaporation were analyzed for composition, revealing a TMAH concentration of 6.1% and a water content of 7.23%.

[0063] Comparative Example 2

[0064] First, the TMAH pentahydrate crystalline compound was dissolved in ethylene glycol (EG) solution and stirred at room temperature until the TMAH crystals were completely dissolved, yielding 500 ml of TMAH ethylene glycol solution. The TMAH content was measured to be 3.3% and the water content to be 6.5%.

[0065] The evaporation chamber was preheated at 50℃ and pressure at 0.02 MPa. The thin-film evaporation temperature was 75℃ and pressure at 500 Pa, with a feed rate of 0.4 ml / s. The heavy components collected after evaporation were analyzed for composition, revealing a TMAH concentration of 6.9% and a water content of 1.35%.

[0066] Comparative Example 3

[0067] First, the TMAH pentahydrate crystalline compound was dissolved in propylene glycol (PG) solution. The mixture was stirred at room temperature until the TMAH crystals were completely dissolved, resulting in a 500 ml TMAH propylene glycol solution. The TMAH content was measured to be 2.8% and the water content to be 3.91%.

[0068] The evaporation chamber was preheated at 50℃ and pressure at 0.02 MPa, while the thin-film evaporation temperature was 75℃ and pressure at 500 Pa. The heavy components collected after evaporation were analyzed for composition, revealing a TMAH concentration of 11.3% and a water content of 1.06%.

[0069] In photoresist cleaning solutions, adding one equivalent of tetramethylammonium hydroxide solution introduces three equivalents of water. This water introduction significantly negatively impacts the stripping and cleaning effect. Firstly, water causes a higher copper corrosion rate. On the one hand, water significantly reduces the cleaning capacity of photoresist (batch cleaning). As product demands increase and chip manufacturing node sizes shrink, advanced chip packaging is moving towards high-density or copper pillar processes. Therefore, higher demands are placed on the performance of photoresist stripping solutions, requiring not only strong stripping and cleaning capabilities but also lower metal corrosion rates and higher cleaning capacity (the number of wafers cleaned per unit volume of photoresist stripping solution). Reducing the water content of the photoresist stripping solution is the most effective method. Test results from US Patent US10072237B2 show that when the water content of the photoresist stripping solution exceeds 1.5%, it leads to discoloration or high corrosion of Cu. When the water content is less than 1%, the copper corrosion rate can be less than [missing information]. (Batch cleaning) can significantly increase the photoresist stripping and cleaning load, so that the metal and / or passivation materials on the substrate are little or no corroded, which can meet the requirements of the nanometer-level chip packaging process.

[0070] The water of crystallization in tetramethylammonium hydroxide pentahydrate crystals is bound by hydrogen bonds. The common method for removing water of crystallization from hydrated compounds is high-temperature heating. However, tetramethylammonium hydroxide is highly hygroscopic and heat-sensitive, easily decomposing upon heating. It has a melting point of 62–71°C and a boiling point of 120°C, and completely decomposes and vaporizes at 135–145°C. Experiments have shown that heating cannot remove the water of crystallization, and TMAH gradually decomposes. Heating under vacuum drying conditions only removes a small amount of water of crystallization. Dissolving tetramethylammonium hydroxide in an organic solvent with a stronger affinity for water converts the water of crystallization into free water. Thin-film evaporation removes the free water while removing the organic solvent, thus achieving dehydration. However, conventional methods such as evaporation and distillation cause significant decomposition of tetramethylammonium hydroxide, failing to meet the requirements. Therefore, controlling the water content of the tetramethylammonium hydroxide solution to be less than 1% and maintaining the TMAH content above 10% is particularly difficult. Thin-film evaporation is characterized by separating substances under low temperature and high vacuum conditions. In this process, the evaporation temperature of tetramethylammonium hydroxide pentahydrate is 75-85℃, which is far from the temperature at which TMAH begins to decompose. Analysis of the TMAH concentration after evaporation in Examples 1-4 shows that TMAH was basically not decomposed by heat during the evaporation process.

[0071] Table 1. Operating parameters of TMAH dehydration comparative and example cases

[0072]

[0073]

[0074] In Table 1, the content of each component refers to the mass percentage content.

[0075] This invention designs a dynamic liquid supply device in conjunction with thin-film evaporation, and as shown in Table 1, it achieves significant results. In Examples 1-4, the water content of the tetramethylammonium hydroxide solution is all below 0.5%. Comparative Examples 1-3 did not employ a dynamic liquid supply device between the pump and the thin-film evaporation chamber, while Examples 1-4 incorporated a dynamic liquid supply device between the pump and the thin-film evaporation chamber. A comparison between Comparative Examples 1-3 and Examples 1-4 shows that after activating the dynamic liquid supply device, the product water content is lower than without it.

[0076] Table 2 lists the water content of products obtained in different embodiments of the present invention and products obtained in other patents. In Table 2, the concentration and water content of the products refer to mass percentage.

[0077] Table 2

[0078] organic solvents TMAH concentration / % Product moisture content / % CN114195655A PG 13.3 0.43 CN112752746B HG 24.7 0.58 Example 4 PG 14.2 0.15

[0079] In Example 1 of CN114195655A, tetramethylammonium hydroxide crystals containing five molecules of water of crystallization are dissolved in an organic solvent to obtain a raw material liquid for a tetramethylammonium hydroxide organic solution. The raw material liquid is preheated by the first stage of distillation in a two-stage scraped membrane molecular distillation apparatus and then enters the second stage of distillation to obtain a tetramethylammonium hydroxide organic solution with a water content of 0.4-0.87 wt%.

[0080] In Example 2 of CN112752746B, a tetramethylammonium hydroxide / propyl gallate mixed solution was prepared by mixing tetramethylammonium hydroxide and propyl gallate in a ratio of 7:3. The tetramethylammonium hydroxide / propyl gallate mixed solution was then mixed with dimethyl sulfoxide and E200 solution in a ratio of 7:8:5 in a pure PE mixing tank with ventilation equipment. After ventilating and stirring for 30 minutes, the mixture was filtered through a 0.2μm filter and then subjected to anhydrous stripping by dry etching.

[0081] The TMAH anhydrous stripping solutions prepared by the above-mentioned existing methods all have significant stripping effects on residues from dry metal etching. However, their high water content corrodes copper and other wiring metals, leading to circuit breaks and ultimately chip defects. Therefore, stripping solutions with lower water content are needed to reduce circuit failures caused by metal corrosion. This invention provides a tetramethylammonium hydroxide organic solution with a water content of 0.15-0.48 wt%. The tetramethylammonium hydroxide obtained by the method of this invention is used in the manufacturing process of high-purity anhydrous semiconductor photoresist cleaning agents.

[0082] As clearly shown in Table 2, the water content of the TMAH organic solution obtained in the embodiments of the present invention is significantly lower than that of the products obtained by the prior art. Compared with traditional thin-film evaporation devices, the device of the present invention adds an internal circulation pipeline. When the device is started or stopped, or when the feed conditions fluctuate, the use of an acoustic atomizer can ensure that the product quality meets the standards. This control method and internal circulation system can adapt to fluctuations in feed concentration, automatically find and maintain the optimal evaporation state, improve the robustness of the process, and enhance product quality.

[0083] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A thin-film evaporation dehydration device for tetramethylammonium hydroxide pentahydrate crystals based on dynamic liquid supply, characterized in that... The system includes a thin-film evaporator, an acoustic atomizer, an evaporation chamber, and a cold trap. The acoustic atomizer is located at the inlet of the thin-film evaporation chamber of the thin-film evaporator and is connected to the evaporation chamber via a pipe. The outer periphery of the thin-film evaporator is a thin-film evaporation surface, on which a temperature sensor is installed. The temperature sensor is connected to the control system of the acoustic atomizer. The cold trap is connected to the light component distillation range pipeline of the thin-film evaporator. The lower end of the thin-film evaporator is connected to the acoustic atomizer via a pipe, and an internal circulation pump is installed on the pipe. A product collection device is installed at the lower end of the thin-film evaporator, and a light component collection device is installed at the lower end of the cold trap. The cold trap is also connected to a constant-temperature water bath and a vacuum pump. The thin-film evaporator is also connected to a vacuum pump and a constant-temperature oil bath. The evaporation chamber is also connected to a vacuum pump and a constant-temperature water bath.

2. The thin-film evaporation dehydration device for tetramethylammonium hydroxide pentahydrate crystals based on dynamic liquid supply according to claim 1, characterized in that, The second constant temperature water bath device is connected to the cold trap through a cooling water inlet and a cooling water outlet, and the cold trap is connected to the second vacuum pump.

3. The thin-film evaporation dehydration device for tetramethylammonium hydroxide pentahydrate crystals based on dynamic liquid supply according to claim 1, characterized in that, The upper end of the thin-film evaporator is connected to a constant-temperature oil bath via a heat-conducting oil pipeline.

4. The thin-film evaporation dehydration device for tetramethylammonium hydroxide pentahydrate crystals based on dynamic liquid supply according to claim 1, characterized in that, The evaporation chamber is connected to the first constant temperature water bath device; the first vacuum pump is connected to the thin film evaporator and the evaporation chamber through pipes respectively.

5. A method for dehydrating tetramethylammonium hydroxide pentahydrate crystals by thin-film evaporation based on dynamic liquid supply using the apparatus described in any one of claims 1-4, characterized in that, Tetramethylammonium hydroxide crystals containing five molecules of water of crystallization are dissolved in an organic solvent to prepare a tetramethylammonium hydroxide organic solution raw material. The raw material is preheated and preliminarily separated in an evaporation chamber. The preheated material is atomized by an acoustic atomizer and enters the thin-film evaporation chamber. The pulse operating frequency of the acoustic atomizer is 20Hz-500Hz, and the temperature of the thin-film evaporation is controlled at 65-75℃, and the pressure is 100-1000Pa. A temperature sensor installed on the thin-film evaporation surface transmits the real-time temperature signal to the control system of the acoustic atomizer, which converts it into a pulse signal to control the duty cycle D of the acoustic atomizer to change with the temperature, thereby performing dynamic spraying and liquid supply. This ensures that the liquid film thickness on the thin-film evaporation surface is controlled at 0.5-1mm.

6. The method for dehydrating tetramethylammonium hydroxide pentahydrate crystals by thin-film evaporation based on dynamic liquid supply according to claim 5, characterized in that, The sonic atomizer dynamically supplies liquid by controlling its duty cycle D to vary with temperature. During the preheating and start-up phase, when the detected temperature T < 60℃, the atomizer operates at its lowest duty cycle D0. When the detected temperature T is between 60℃ and 68℃, the atomizer's duty cycle D linearly increases from the lowest duty cycle D0 to the highest duty cycle Dopt, satisfying the relationship: D = D0 + K1 * (T - 60), where K1 is the heating gain coefficient. When the detected temperature T is between 68℃ and 74℃, the duty cycle D is maintained at the highest duty cycle Dopt. When the detected temperature T > 74℃, the duty cycle D linearly decreases from Dopt, satisfying the relationship: D = Dopt - K2 * (T - 74), where K2 is the protection attenuation coefficient, and K2 > K1. If the detected temperature of the film evaporation surface reaches 78℃, the atomizer is fully activated for rapid cooling.

7. The method for dehydrating tetramethylammonium hydroxide pentahydrate crystals by thin-film evaporation based on dynamic liquid supply according to claim 6, characterized in that, The minimum duty cycle D0 is 5%-15%; the Dot value is 40%-70%. The heating gain coefficient K1 is set to 5% / ℃-15% / ℃; the protection attenuation coefficient K2 is set to 20% / ℃-40% / ℃.

8. The method for dehydrating tetramethylammonium hydroxide pentahydrate crystals by thin-film evaporation based on dynamic liquid supply according to claim 5, characterized in that, The evaporation chamber is preheated at a temperature of 40-50℃ and a pressure of 0.01-0.02 MPa.

9. The method for dehydrating tetramethylammonium hydroxide pentahydrate crystals by thin-film evaporation based on dynamic liquid supply according to claim 5, characterized in that, During the preheating and start-up phase, the product collection device is turned off, the internal circulation pump is turned on, and the recombinant liquid is pumped back into the feed pipeline by the internal circulation pump and enters the sonic atomizer, where it is separated again on the thin film evaporator. After the preheating and start-up phase is completed, the internal circulation pump is turned off and product collection begins.

10. The method for dehydrating tetramethylammonium hydroxide pentahydrate crystals by thin-film evaporation based on dynamic liquid supply according to claim 5, characterized in that, The organic solvent is DMSO, 1,2-propanediol, or ethylene glycol; the concentration of tetramethylammonium hydroxide after dehydration of the tetramethylammonium hydroxide organic solution is 10-15 wt%.

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