Ultrasonic cleaning method for stainless steel chamber of ion implanter

Abstract

The application discloses an ultrasonic cleaning method for a stainless steel cavity of an ion implanter. The method comprises the following steps: S1, checking whether the stainless steel cavity is damaged, if not, sequentially performing hanging, flushing, pre-washing immersion, re-flushing, then performing first ultrasonic cleaning, then performing third flushing, blowing dry and hanging; S2, using fine sandpaper with different mesh numbers to grind the stainless steel cavity after blowing dry and blowing clean the surface, then sequentially performing flushing, pre-washing immersion and re-flushing; S3, performing second ultrasonic cleaning on the stainless steel cavity and then performing flushing; S4, performing once normal-temperature pure water immersion and once warm pure water immersion on the stainless steel, then blowing dry and hanging. The application can at least solve the problem of insufficient cleanliness of the cleaning method for the stainless steel cavity of the ion implanter in the prior art, and the problem that micro-particles are difficult to be completely removed.

Description

Technical Field

[0001] This application relates to the field of semiconductor equipment component cleaning technology, and more specifically, to an ultrasonic cleaning method for the stainless steel cavity of an ion implanter. Background Technology

[0002] In related technologies, the cleaning method for the stainless steel cavity of an ion implanter involves both coarse and fine grinding, which causes significant wear and tear on the stainless steel cavity, resulting in damage to the weld seams. Repeated coarse grinding can also affect the sealing performance of the stainless steel cavity, thus impacting its lifespan. Furthermore, after coarse grinding, the surface of the stainless steel cavity is relatively rougher, making it more susceptible to adsorption of contaminants and particle formation during the ion implantation process compared to a smooth surface. In addition, using only high-pressure rinsing during the cleaning process results in insufficient surface cleanliness of the stainless steel cavity, potentially leaving behind fine particles that affect the quality of semiconductor materials during ion implantation. Summary of the Invention

[0003] The main objective of this application is to provide an ultrasonic cleaning method for the stainless steel cavity of an ion implanter, in order to solve the problem that the existing cleaning methods for the stainless steel cavity of ion implanters are insufficient in terms of cleanliness and make it difficult to completely remove microparticles.

[0004] According to one aspect of this application, an ultrasonic cleaning method for a stainless steel cavity of an ion implanter is provided, comprising: Step S1: Check whether the stainless steel cavity to be cleaned is damaged. If it is not damaged, hang the stainless steel cavity and then rinse, pre-wash and soak, and rinse again in sequence. Then, perform the first ultrasonic cleaning on the stainless steel cavity at the first predetermined ultrasonic frequency, the first predetermined power density, the first predetermined cleaning time and the first predetermined cleaning temperature. After that, perform the third rinsing, drying and hanging of the stainless steel cavity. Step S2: Grind the dried stainless steel cavity with fine sandpaper of different grits. After grinding, clean the surface of the stainless steel cavity by blowing it clean. Then rinse, pre-wash and soak the stainless steel cavity in sequence, and rinse it again. Step S3: After the second rinsing is completed, the stainless steel cavity is subjected to a second ultrasonic cleaning at a second predetermined ultrasonic frequency, a second predetermined power density, a second predetermined cleaning time, and a second predetermined cleaning temperature, and then the stainless steel cavity is rinsed. Step S4: After rinsing, the stainless steel is first immersed at a first predetermined temperature and a first predetermined time, and then the stainless steel cavity is second immersed at a second predetermined temperature and a second predetermined time. After that, the stainless steel cavity is dried and hung up.

[0005] Furthermore, in step S2, the fine sandpaper includes white corundum sandpaper or brown corundum sandpaper.

[0006] Furthermore, in step S2, the fine sandpaper has a mesh size of 240 to 400.

[0007] Furthermore, in step S2, during the grinding of the stainless steel cavity using fine sandpaper of different grits, the number of sheets of fine sandpaper of different grits used per unit area of ​​the stainless steel cavity includes 10 to 20 sheets.

[0008] Further, in step S1: The first predetermined ultrasonic frequency includes 20kHz to 40kHz; The first predetermined power density includes 0.3 W / cm². 2 ; The first scheduled cleaning time includes 5 to 10 minutes; The first predetermined cleaning temperature ranges from 20℃ to 40℃.

[0009] Further, in step S3: The second predetermined ultrasonic frequency includes 40kHz to 80kHz; The second predetermined power density includes 0.5 W / cm². 2 ; The second scheduled cleaning time includes 10 to 20 minutes; The second predetermined cleaning temperature ranges from 20°C to 40°C.

[0010] Further, in step S4, the first predetermined temperature includes 20°C to 25°C; and / or, the first predetermined time includes 5 min to 10 min.

[0011] Further, in step S4, the second predetermined temperature includes 35°C to 45°C; and / or, the second predetermined time includes 10 min to 20 min.

[0012] Furthermore, in steps S1 and S2, the stainless steel cavity is placed in a pre-washing tank for pre-washing and soaking, and the pre-washing tank is equipped with a ventilation device for ventilating the pre-washing tank.

[0013] Furthermore, the cleaning solution for ultrasonic cleaning comprises: a degreasing agent and deionized water, wherein the degreasing agent comprises sodium metasilicate pentahydrate, a surfactant, and sodium gluconate; and / or, The volume fraction of the degreasing agent is 1% to 3%.

[0014] In this application, the entire process is structured as follows: Step S1 (pre-treatment coarse washing) → Step S2 (grinding + intermediate cleaning) → Step S3 (fine washing) → Step S4 (gradual rinsing and drying). Each step clears obstacles for the next, and the next compensates for the limitations of the previous step, preventing cross-contamination of contaminants between processes. Furthermore, unlike existing solutions that only wash without cleaning, the progressive grinding in Step S2 of this application simultaneously corrects the cavity surface during cleaning, removing processing marks and oxide layers, improving smoothness, and reducing porosity, upgrading the stainless steel cavity surface from clean to usable quality. The smooth surface after grinding makes the high-frequency ultrasonic cavitation effect in Step S3 more uniform, and the graded rinsing in Step S4 more effective at removing residues, forming a positive cycle of surface optimization → deep cleaning → zero residue. Ultimately, this results in a stainless steel cavity surface that is both clean and possesses low adsorption and high sealing properties, ensuring ion beam purity and vacuum stability. In other words, this application not only makes the stainless steel surface rougher and smoother, reducing the adsorption of particulate matter, but also further improves the cleanliness of the stainless steel cavity. Attached Figure Description

[0015] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, are illustrative and descriptive, serving to explain this application and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic flowchart of an ultrasonic cleaning method for the stainless steel cavity of an ion implanter disclosed in an embodiment of this application. Detailed Implementation

[0016] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0017] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0018] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0019] As described in the background section, in related technologies, the cleaning method for the stainless steel cavity of an ion implanter involves coarse grinding followed by fine grinding, which causes significant wear to the stainless steel cavity, resulting in damage to the weld seams. Repeated coarse grinding can also affect the sealing performance of the stainless steel cavity, thus impacting its lifespan. Furthermore, after coarse grinding, the surface of the stainless steel cavity is relatively rougher, making it more susceptible to adsorption of contaminants and particle formation during the ion implantation process compared to a smooth surface. In addition, using only high-pressure rinsing during the cleaning process results in insufficient surface cleanliness of the stainless steel cavity, potentially leaving fine particles that affect the quality of semiconductor materials during ion implantation. Therefore, this application provides a novel ultrasonic cleaning method for the stainless steel cavity of an ion implanter. This ultrasonic cleaning method for the stainless steel cavity of an ion implanter can improve the cleanliness of the cavity. The ultrasonic cleaning method for the stainless steel cavity of the ion implanter of this application will be described below with reference to the accompanying drawings.

[0020] See Figure 1 As shown in the figure, this application provides an ultrasonic cleaning method for the stainless steel cavity of an ion implanter.

[0021] Specifically, the ultrasonic cleaning method for the stainless steel cavity of the ion implanter includes: Step S1: Check whether the stainless steel cavity to be cleaned is damaged. If it is not damaged, hang the stainless steel cavity and then rinse, pre-wash and soak, and rinse again in sequence. Then, perform the first ultrasonic cleaning on the stainless steel cavity at the first predetermined ultrasonic frequency, the first predetermined power density, the first predetermined cleaning time and the first predetermined cleaning temperature. After that, perform the third rinsing, drying and hanging of the stainless steel cavity.

[0022] In this application, step S1 is a pretreatment stage. This step can remove some contaminants such as dust, particulate matter and grease from the surface of the stainless steel cavity, which can prepare for the subsequent cleaning steps.

[0023] Specifically, in this application, the stainless steel cavity to be cleaned needs to be inspected first to check for damage. This avoids using cavities with structural defects in the subsequent cleaning process and prevents accidents during hanging or rinsing. If the stainless steel cavity is undamaged after inspection, it is hung. Hanging involves installing lifting rings on the lifting holes of the stainless steel cavity, using slings to lift the cavity and place it on a high-pressure rinsing platform for high-pressure rinsing. In this application, by installing lifting rings on the lifting holes of the stainless steel cavity and using slings for lifting, direct contact between personnel and the working surface of the stainless steel cavity can be avoided, preventing secondary contamination and surface scratches caused by manual operation.

[0024] Furthermore, after hanging and placing the stainless steel cavity on the high-pressure rinsing platform, the stainless steel cavity is subjected to high-pressure rinsing for 10 to 20 minutes. For example, the high-pressure rinsing time can be 10 minutes, 15 minutes, 20 minutes, etc. Within the above rinsing time, the physical impact force of the high-pressure water flow ensures that loose contaminants such as large particles of dust and metal shavings that are not firmly attached to the surface of the stainless steel cavity are thoroughly cleaned. At the same time, within the above cleaning time range, waste of water and electricity resources can be prevented.

[0025] Furthermore, this application also includes a pre-wash tank, and a ventilation device is installed inside the pre-wash tank to ventilate the tank. Exemplarily, compressed air can be used to ventilate the pre-wash tank using the ventilation device; other gases are also possible, but compressed air is preferred to reduce cleaning costs. After the first high-pressure rinse, the stainless steel cavity is suspended in the pre-wash tank for pre-washing and soaking for 5-10 minutes. The pre-wash tank contains deionized water at a temperature of 20°C-30°C. Simultaneously, the ventilation device is opened to ventilate the pre-wash tank to agitate the deionized water. Exemplarily, the pre-washing and soaking time can be 5 minutes, 7 minutes, 10 minutes, etc.; the temperature of the deionized water can be 20°C, 25°C, and 30°C, etc. It is understood that using deionized water for pre-washing and soaking in this application will not leave new contaminants (such as scale, ion residue, etc.) on the surface of the stainless steel cavity, providing favorable conditions for the subsequent first ultrasonic cleaning. Meanwhile, controlling the temperature and soaking time of the deionized water within the aforementioned range can improve cleaning effectiveness and reduce cleaning costs. Furthermore, in this pre-wash soaking process, the stainless steel chamber is immersed in deionized water with compressed air agitation, which softens and dissolves some stubborn greases and process residues. Simultaneously, the agitation of the air bubbles impacts the stainless steel surface, enabling efficient removal of contaminants.

[0026] Furthermore, after the pre-wash soaking, the stainless steel cavity is hoisted onto the high-pressure rinsing platform for high-pressure rinsing. During this high-pressure rinsing process, the rinsing time is also 10-20 minutes. This setup prevents contaminants from the pre-wash tank from being carried into the ultrasonic cleaning process, avoids cross-contamination, and thus improves the effectiveness of subsequent ultrasonic cleaning.

[0027] Furthermore, in this application, the stainless steel cavity is subjected to a first ultrasonic cleaning at a first predetermined ultrasonic frequency, a first predetermined power density, a first predetermined cleaning time, and a first predetermined cleaning temperature. Specifically, the first predetermined ultrasonic frequency includes 20kHz to 40kHz; exemplarily, the first predetermined ultrasonic frequency can be 20kHz, 25kHz, 30kHz, or 40kHz, etc.; the first predetermined power density includes a value greater than or equal to 0.3W / cm². 2 For example, the first predetermined power density may be 0.3 W / cm². 2 1.0W / cm 2 5.0W / cm 2The first predetermined cleaning time includes 5 min to 10 min, for example, the first predetermined cleaning time can be 5 min, 6 min, 10 min, etc.; the first predetermined cleaning temperature includes 20℃ to 40℃, for example, the first predetermined cleaning temperature can be 20℃, 25℃, 30℃, and 40℃, etc. Meanwhile, in this application, the cleaning fluid in the ultrasonic cleaning process includes a degreasing agent and deionized water with a volume fraction of 1% to 3%, wherein the degreasing agent is composed of sodium metasilicate pentahydrate, a surfactant, and sodium gluconate, and the volume ratio of sodium metasilicate pentahydrate, surfactant, and sodium gluconate is 4:2:1.

[0028] Specifically, in the first ultrasonic cleaning process, the first predetermined ultrasonic frequency is set between 20kHz and 40kHz, which generates large-scale cavitation bubbles and high-intensity impact force. The collapse of the cavitation bubbles produces localized high temperature, high pressure, and micro-jets, effectively removing stubborn stains from the stainless steel cavity surface. This setting also vigorously agitates the cleaning fluid, forcing it to impact and penetrate at high speed into every crevice of the contaminants and the stainless steel cavity surface, greatly improving the chemical reaction rate and efficiency. The first predetermined power density is greater than or equal to 0.3W / cm². 2 This ensures that the mechanical driving force has sufficient strength, resulting in better cleaning performance.

[0029] Meanwhile, in this application, the degreasing agent in the ultrasonic cleaning solution can improve the efficiency of oil film treatment. Sodium metasilicate pentahydrate provides strong alkalinity, undergoes a saponification reaction with greases, converting water-insoluble animal and vegetable oils into water-soluble sodium fatty acids. It also prevents micro-corrosion on the stainless steel surface during cleaning, protecting the stainless steel cavity. The surfactant, with one end lipophilic and the other hydrophilic, can encapsulate unsaponifiable greases such as mineral oil through emulsification, dispersing them in water. Sodium gluconate is a strong chelating agent, improving the stability of the cleaning solution and providing corrosion inhibition protection for the stainless steel surface, preventing corrosion of the stainless steel cavity by the alkaline environment. Furthermore, in this application, the volume ratio of sodium metasilicate pentahydrate, surfactant, and sodium gluconate is 4:2:1, allowing these three components to mutually promote each other, forming a stable, efficient, and easy-to-rinse cleaning system.

[0030] Furthermore, in this application, the volume fraction of the degreasing agent is 1% to 3%. This ensures effective degreasing while preventing foam from interfering with the first ultrasonic cavitation, gently protecting the stainless steel material and avoiding corrosion risks. The low concentration of 1% to 3% also means a low chemical content in the cleaning solution, allowing subsequent cleaning processes to remove residues more quickly and thoroughly, preventing the formation of ionic residues on the cavity surface. In addition, in this application, the first predetermined cleaning time includes 5 to 10 minutes. This range ensures sufficient time for the cleaning solution to react with some contaminants (such as grease) before ultrasonic waves can remove them. The first predetermined cleaning temperature includes 20°C to 40°C, significantly accelerating the saponification and emulsification reactions while avoiding excessively high temperatures that could lead to energy waste or rapid evaporation of the cleaning solution.

[0031] Furthermore, after the first ultrasonic cleaning, the stainless steel cavity is hoisted onto a high-pressure rinsing platform for high-pressure rinsing. After high-pressure rinsing, the stainless steel cavity is dried using compressed air. Alternatively, other methods can be used to dry the stainless steel surface. This setup thoroughly removes all contaminants and chemical residues generated during the first ultrasonic cleaning, creating an absolutely dry and clean initial surface for the subsequent grinding process, ensuring grinding effectiveness and preventing secondary contamination.

[0032] In other words, in this application, step S1 can remove large-volume, easily detachable contaminants (such as transport dust and surface oil), preventing these impurities from entering subsequent fine processes (such as grinding and high-frequency ultrasound), scratching the cavity surface, or reducing the efficiency of fine cleaning.

[0033] Step S2: Grind the dried stainless steel cavity using fine sandpaper of different grits. After grinding, clean the surface of the stainless steel cavity by blowing it clean, and then rinse, pre-wash and soak the stainless steel cavity in sequence, followed by rinsing again. In this application, due to the structural limitations of the stainless steel cavity, manual grinding with sandpaper is used.

[0034] Specifically, in this application, the fine sandpaper can be either white fused alumina sandpaper or brown fused alumina sandpaper. Both white and brown fused alumina are high-hardness abrasives with a reasonable hardness difference from stainless steel, effectively cutting surface impurities without causing micro-cracks on the cavity surface due to excessive hardness. White fused alumina sandpaper, in particular, has high abrasive purity, uniform particle size, gentle cutting force, and fine grinding marks, resulting in superior surface finish after grinding. It is suitable for fine grinding processes with extremely high surface quality requirements, and white fused alumina sandpaper is preferred in this application. Furthermore, in this application, the grit of the fine sandpaper ranges from 240 to 400 mesh. For example, the grit of the fine sandpaper includes 240, 320, and 400 mesh, with a progressive fine grinding process of 240 mesh → 320 mesh → 400 mesh between the three grits. This precisely refines the surface texture, ultimately improving the surface finish of the cavity and reducing porosity. Furthermore, during the grinding of the stainless steel cavity using sandpaper of different grits, the number of sheets of sandpaper used per unit area of ​​the stainless steel cavity ranges from 10 to 20. This setup ensures that the grinding force at each grit is adequate, preventing incomplete grinding in certain areas due to insufficient sandpaper (less than 10 sheets) and over-grinding due to excessive sandpaper (more than 20 sheets), which could lead to dimensional deviations. Compared to existing technologies, this application eliminates the need for coarse sandpaper (e.g., 80 grit, 120 grit) to first coarsely grind the stainless steel cavity, followed by fine grinding with 240 grit and 320 grit sandpaper. Instead, it directly uses 240 grit sandpaper for fine grinding, while increasing the grit of the fine sandpaper to 400 grit. This setup reduces the wear and tear on the stainless steel cavity body caused by coarse grinding, thereby reducing the risk of leakage at the cavity welds due to wear. Meanwhile, the fine grinding process was optimized, and the mesh size of the fine sandpaper was increased, resulting in a smoother and less rough stainless steel surface, thus reducing the adsorption of particulate matter.

[0035] Furthermore, grinding removes microscopic scratches, oxide layers, and any contaminants that may have embedded in the surface of the stainless steel cavity from previous use. This creates a smoother, more uniform surface, significantly reducing the adhesion points of particulate and molecular contaminants, making the cavity less prone to contamination and easier to clean during subsequent use. This setup also provides a clean and uniform metal substrate for subsequent secondary ultrasonic cleaning and final process applications. It is important to note that before wet cleaning, the ground surface must be thoroughly cleaned with compressed air to prevent powder from mixing with water and forming a difficult-to-remove paste that could clog crevices. In this application, after cleaning the dust from the surface of the stainless steel cavity with compressed air, the cavity is then hoisted to a high-pressure rinsing platform for high-pressure rinsing for 10-20 minutes. After rinsing, the cavity is then hoisted into a pre-washing tank for immersion for 5-10 minutes. These two steps are identical to those in step S1, and their effects will not be elaborated here. After pre-washing and soaking, the stainless steel cavity is hoisted to a high-pressure rinsing platform and rinsed under high pressure for 20 to 30 minutes. For example, the high-pressure rinsing time can be 20 minutes, 25 minutes, or 30 minutes. This high-pressure rinsing can thoroughly rinse away all residual contaminants that have been loosened and suspended by the soaking, ensuring that the surface of the stainless steel cavity is free of any particles from the grinding process when it enters the second ultrasonic fine cleaning.

[0036] In other words, in this application, step S2 optimizes the surface condition of the stainless steel cavity through progressive grinding and instant cleaning, and thoroughly removes the new impurities generated by grinding, providing a clean surface with low porosity and no residue for the subsequent second ultrasonic cleaning, ensuring that the second ultrasonic cleaning can exert maximum efficiency and ultimately achieve the impeccable ultra-high cleanliness required by semiconductor processes.

[0037] Step S3: After the second rinsing, the stainless steel cavity is subjected to a second ultrasonic cleaning at a second predetermined ultrasonic frequency, a second predetermined power density, a second predetermined cleaning time, and a second predetermined cleaning temperature, and then the stainless steel cavity is rinsed.

[0038] In this application, the first ultrasonic cleaning (low frequency, high power) has removed most of the macroscopic contaminants and grease. The grinding and subsequent rinsing in step S2 further remove the particles generated during grinding. At this point, the surface of the cavity is left with the most firmly attached, smallest submicron-sized particles and molecular-level contaminants. The second ultrasonic cleaning is designed to remove stubborn contaminants that the previous steps could not remove. In this application, the stainless steel cavity is subjected to a second ultrasonic cleaning at a second predetermined ultrasonic frequency, a second predetermined power density, a second predetermined cleaning time, and a second predetermined cleaning temperature. Specifically, the second predetermined ultrasonic frequency includes 40kHz to 80kHz; for example, the second predetermined ultrasonic frequency can be 41kHz, 55kHz, 70kHz, or 80kHz. The second predetermined power density includes ≥0.5W / cm². 2 For example, the second predetermined power density includes 0.5 W / cm². 2 1.5W / cm 2 5W / cm 2 The second predetermined cleaning time includes 10 min to 20 min, for example, the second predetermined cleaning time can be 10 min, 15 min and 20 min, etc.; the second predetermined cleaning temperature includes 20℃ to 40℃, for example, the second predetermined cleaning temperature can be 20℃, 30℃ and 40℃, etc.

[0039] It is worth noting that during the second ultrasonic cleaning process, the ultrasonic cleaning fluid is the same as the cleaning fluid used in the first ultrasonic cleaning in step S1.

[0040] Specifically, when the second predetermined ultrasonic frequency is within the aforementioned range, this high-frequency ultrasonic frequency can generate tiny cavitation bubbles, penetrating deep into the minute textures and pores of the ground surface to precisely remove micron-sized particles and residual oil. Simultaneously, higher power density and longer cleaning time enhance the cleaning effect, ensuring the stainless steel cavity surface achieves an ultra-high cleanliness level with no particles and low porosity. Meanwhile, the second ultrasonic cleaning follows the "grinding + preliminary cleaning" of step S2. With no obvious impurities on the stainless steel cavity surface, the high-frequency ultrasound in step S3 can focus on refined purification, avoiding impurities interfering with the fine cleaning efficiency. After ultrasonic cleaning, the stainless steel cavity is suspended on a high-pressure rinsing platform for 20-30 minutes of high-pressure rinsing. This quickly washes away the tiny impurities and residual cleaning fluid removed by the ultrasound, preventing these substances from drying and adhering to the surface or reacting with subsequent pure water rinsing to form ionic residues. At the same time, the high-pressure water flow can penetrate deep into the complex structure of the stainless steel cavity (such as interfaces and crevices), ensuring that all areas in the fine cleaning stage are residue-free, reducing the burden on the final pure water and warm pure water rinsing.

[0041] Step S4: After rinsing, the stainless steel is first immersed at a first predetermined temperature and time, and then immersed a second time at a second predetermined temperature and time. After that, the stainless steel cavity is dried and hung up. Both immersions use high-purity deionized water (conductivity ≤1μS / cm) without any additional chemicals, avoiding corrosion or oxidation of the polished stainless steel surface and extending the service life of the cavity.

[0042] Specifically, in this application, the first predetermined temperature includes 20℃~25℃, and for example, the first predetermined temperature can be 20℃, 22℃, and 25℃, etc.; the first predetermined time includes 5min~10min, and for example, the first predetermined time can be 5min, 7min, and 10min, etc. The second predetermined temperature includes 35℃~45℃, and for example, the second predetermined temperature can be 35℃, 38℃, 40℃, and 45℃, etc. This temperature is controlled below the threshold of stainless steel heat deformation, which can ensure the residual dissolution efficiency and avoid the impact of high temperature on the dimensional accuracy of the cavity, thus balancing cleaning effect and material protection. The second predetermined time includes 10min~20min, and for example, the second predetermined time can be 10min, 15min, and 20min, etc.

[0043] Understandably, in this application, the first soaking is performed in a pure water tank at room temperature, while simultaneously using a ventilation device to introduce air into the pure water tank, such as clean compressed air. Thus, using room temperature, flowing or agitated deionized water allows for effective diffusion, dispersing the trace amounts of cleaning agent and most of the ionic contaminants remaining after the second ultrasonic cleaning throughout the pure water tank, thereby significantly reducing their concentration.

[0044] The second soaking is conducted in a warm, pure water tank equipped with a ventilation system to introduce clean compressed air. During the second soaking, the water temperature is maintained at 35°C to 45°C, significantly reducing the surface tension of the water. Lower surface tension allows water to more easily swirl and detach from the metal surface, effectively removing any remaining ions and particles. Simultaneously, heat increases the kinetic energy of water molecules and contaminants, weakening the adsorption forces (such as van der Waals forces) between contaminants and the stainless steel cavity surface, making it easier for these trace contaminants to detach. Furthermore, a final rinsing with heated deionized water, followed by the rapid and uniform evaporation of moisture from the stainless steel cavity surface when it is removed using clean, dry compressed air, prevents concentrated contaminant rings (i.e., water stains) from forming at the edges of water droplets during drying. After drying, hang it up immediately to prevent the stainless steel cavity from staying in the cleaning area for too long and getting dusty, ensuring the cleanliness of the final state, and directly connecting to the subsequent assembly or storage process to form a complete process closed loop.

[0045] It is worth noting that the second soaking process takes longer than the first soaking process. This is to ensure that the heat can fully penetrate the entire complex stainless steel cavity, ensuring the removal of contaminants and achieving a uniform temperature throughout the stainless steel cavity.

[0046] In other words, this application follows a complete process of steps S1 (pretreatment coarse cleaning) → S2 (grinding + intermediate cleaning) → S3 (fine cleaning) → S4 (gradual rinsing and drying). Each step clears obstacles for the next, and the next compensates for the limitations of the previous step, preventing cross-contamination of contaminants between processes. Furthermore, unlike existing solutions that only clean without finishing, the progressive grinding in step S2 of this application simultaneously corrects the cavity surface during the cleaning process, removing processing marks and oxide layers, improving flatness, and reducing porosity, upgrading the stainless steel cavity surface from clean to usable quality. The smooth surface after grinding makes the high-frequency ultrasonic cavitation effect in step S3 more uniform, and the graded rinsing in step S4 more effective at removing residues, forming a positive cycle of surface optimization → deep cleaning → zero residue. Ultimately, this results in a stainless steel cavity surface that is both clean and possesses low adsorption and high sealing properties, ensuring ion beam purity and vacuum stability.

[0047] To verify the technical effects of this application, the following specific embodiments are provided: Example 1 1. Basic experimental conditions Cleaning object: Stainless steel chamber of ion implanter; Initial condition: The stainless steel chamber surface has machining marks, roughness Ra=0.7μm~0.8μm, and floating oil 300mg / cm³.2 ~400mg / cm 2 Micron-sized (greater than 0.5μm) particles (200 particles / cm²) 2 ~300 pieces / cm 2 The stainless steel cavity is undamaged.

[0048] 2. Common equipment: high-pressure rinsing platform (pressure 5MPa), pre-washing tank, ventilation device (clean and dry compressed air, purity 99.99%), ultrasonic cleaning tank (frequency adjustable 20kHz~80kHz), pure water tank (conductivity ≤1μS / cm), warm pure water tank (conductivity ≤1μS / cm).

[0049] 3. Ultrasonic cleaning solution: 2% degreasing agent by volume (volume ratio, sodium metasilicate pentahydrate: surfactant: sodium gluconate = 4:2:1) + deionized water.

[0050] Step S1: After inspecting the stainless steel cavity, hang it up and high-pressure rinse it with deionized water for 15 minutes. After rinsing, hoist the stainless steel cavity into a pre-washing tank (30℃ deionized water, aerated and stirred) and soak it for 10 minutes, then high-pressure rinse it for another 15 minutes. Then, perform the first ultrasonic cleaning (ultrasonic frequency 30kHz, power density 0.4W / cm³). 2 (Temperature 30℃, time 8min); then the stainless steel cavity is hoisted to the high-pressure flushing platform and flushed for 15min. After that, the stainless steel cavity is dried with clean and dry compressed air and then hung up.

[0051] Step S2 involves manual grinding using 240-mesh, 320-mesh, and 400-mesh white corundum sandpaper. For each unit area of ​​the stainless steel cavity, 15 sheets of white corundum sandpaper of each mesh size are used. After grinding, the cavity is purged with clean, dry compressed air, followed by high-pressure rinsing for 15 minutes. Then, the stainless steel cavity is placed in a pre-washing tank (30℃ deionized water, aerated and stirred) for 8 minutes, and then high-pressure rinsed for 25 minutes.

[0052] Step S3: Perform a second ultrasonic cleaning on the stainless steel cavity (frequency 60kHz, power density 0.6W / cm²). 2 (Temperature 30℃, time 15min), then high pressure rinsing for 25min.

[0053] Step S4: Perform graded soaking on the stainless steel cavity. First soaking (pure water bath at 25℃, soaking for 8 minutes, with aeration and stirring); second soaking (warm pure water bath at 40℃, soaking for 15 minutes, with aeration and stirring). Then, dry the stainless steel cavity and hang it up.

[0054] After undergoing the above processing steps, the stainless steel cavity was tested for the following indicators, and the test results are as follows:

[0055] Comparative Example 1 In this embodiment, the steps are basically the same as in Embodiment 1, except that step S2 (i.e., the grinding step) is missing. After the above processing steps are performed sequentially, the stainless steel cavity is tested for the following indicators, and the test results are as follows:

[0056] Comparative Example 2 In this embodiment, the steps are basically the same as in Embodiment 1. The difference is that in step S2 of this embodiment, 240-mesh and 320-mesh white corundum sandpaper are used for grinding. After the above processing steps are performed sequentially, the stainless steel cavity is tested for the following indicators, and the test results are as follows:

[0057] Comparative Example 3 In this embodiment, the steps are basically the same as in Embodiment 1, except that in this embodiment, only one ultrasonic cleaning is used in step S1 (ultrasonic frequency 30kHz, power density 0.4W / cm²). 2 After undergoing the above processing steps (temperature 30℃, time 8min), the stainless steel cavity was tested for the following indicators, and the test results are as follows:

[0058] Comparative Example 4 In this embodiment, the steps are basically the same as in embodiment 1, except that in this embodiment, only one ultrasonic cleaning is used in step S3 (ultrasonic frequency 60kHz, power density 0.6W / cm², temperature 30℃, time 15min). After the above processing steps are performed sequentially, the stainless steel cavity is tested for the following indicators, and the test results are as follows:

[0059] Comparative Example 5 In this embodiment, the steps are basically the same as in embodiment 1. The difference is that in this embodiment, only the first immersion (pure water bath at 25°C, immersion for 8 minutes, aeration and stirring) is used in step S4. After the above processing steps are performed sequentially, the stainless steel cavity is tested for the following indicators, and the test results are as follows:

[0060] By comparing Example 1 and Comparative Example 1, it can be seen that the absence of a grinding step leads to an increase in the number of particles on the surface of the stainless steel cavity, which cannot be effectively removed by rinsing and ultrasonic waves alone. Furthermore, the lack of a grinding step results in a higher surface roughness of the stainless steel cavity, leading to a greater amount of residual ions on the surface after cleaning.

[0061] By comparing Example 1 and Comparative Example 2, it can be seen that fine grinding with 400-grit sandpaper is necessary. It can effectively remove scratches and residual fine particles that may be generated after grinding with 240-grit and 320-grit sandpaper, thereby reducing the number of particles on the surface of the stainless steel cavity to a lower level.

[0062] Comparative Examples 1, 1, and 2 show that grinding the stainless steel cavity with 240, 320, and 400 mesh grits sequentially is crucial for ensuring the surface roughness and cleanliness of the stainless steel cavity. Without grinding, these particles cannot be removed by high-pressure rinsing and ultrasonic cleaning alone.

[0063] Comparing Example 1 and Comparative Example 3, it can be seen that if the stainless steel cavity is only cleaned once with low-frequency ultrasound before grinding, without subsequent high-frequency ultrasonic cleaning, only large particles of contaminants can be removed, and the ability to remove micron-sized contaminants is limited. This also results in a relatively high amount of residual ions on the stainless steel cavity after cleaning.

[0064] By comparing Example 1 and Comparative Example 4, it can be seen that: during the cleaning process, if low-frequency ultrasonic cleaning is not used before grinding, and high-frequency ultrasonic cleaning is used directly after grinding, a large amount of oil and grinding powder will mix during the grinding stage to form sludge. The sludge will block the grinding action of the sandpaper, making it difficult to completely remove a large number of contaminants on the surface of the stainless steel cavity during high-frequency ultrasonic cleaning. It may even cause particulate matter deposition, thereby increasing the number of particulate matter on the surface of the stainless steel cavity and increasing the amount of ion residue.

[0065] By comparing Example 1 and Comparative Example 5, it can be seen that graded immersion can reduce the number of particles and the amount of residual ions on the surface of the stainless steel cavity.

[0066] By comparing Example 1, Comparative Example 1 and Comparative Example 2, it can be seen that grinding is an indispensable process for stainless steel cavities to go from clean to ultra-clean. At the same time, during the grinding process, increasing the mesh size of the fine sandpaper can improve the surface roughness of the stainless steel cavity, thereby improving the ultra-clean cleaning effect of the stainless steel cavity.

[0067] By comparing Example 1, Comparative Example 3 and Comparative Example 4, it can be seen that simply adding ultrasonic cleaning does not result in a good cleaning effect. In the actual cleaning process, it is necessary to design appropriate parameters and sequence to improve the cleaning effect of stainless steel cavities.

[0068] Furthermore, in the above experiments, the vacuum leakage rates of all embodiments and comparative examples were far superior to the relevant industry standards. In other words, the cleaning process in this application will not damage the structural integrity and sealing performance of the stainless steel cavity.

[0069] In summary, all four steps in this application are indispensable. Step S1 performs pre-cleaning, removing floating oil and large particles from the surface of the stainless steel cavity, preparing it for subsequent grinding steps. Step S2 performs three-step grinding, removing deep-seated particles from the surface of the stainless steel cavity, reducing its surface roughness, and removing attached ions. This step simultaneously improves the number of particles, roughness, and residual ions on the stainless steel cavity surface. Step S3 utilizes high-frequency ultrasound to thoroughly remove fine particles and contaminants generated after grinding. Step S4 employs a two-stage immersion process using room temperature pure water and warm pure water to remove residual ions in a stepwise manner.

[0070] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects: (1) This application uses only fine grinding, which reduces the wear on the stainless steel cavity body caused by existing coarse grinding, thereby reducing the risk of leakage due to wear in the cavity weld.

[0071] (2) This application improves the surface roughness of the stainless steel cavity by increasing the fine sandpaper used for grinding from 320 mesh to 400 mesh, thereby reducing the adsorption of particulate matter.

[0072] (3) In this application, at least two ultrasonic cleanings and multi-stage pure water immersions were used to further improve the cleanliness of the stainless steel cavity.

[0073] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0074] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0075] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An ultrasonic cleaning method for the stainless steel cavity of an ion implanter, characterized in that, include: Step S1: Check whether the stainless steel cavity to be cleaned is damaged. If it is not damaged, hang the stainless steel cavity and then rinse, pre-wash and soak, and rinse again in sequence. Then, perform the first ultrasonic cleaning on the stainless steel cavity at the first predetermined ultrasonic frequency, the first predetermined power density, the first predetermined cleaning time and the first predetermined cleaning temperature. After that, perform the third rinsing, drying and hanging of the stainless steel cavity. Step S2: Grind the dried stainless steel cavity with fine sandpaper of different grits. After grinding, clean the surface of the stainless steel cavity by blowing it clean. Then rinse, pre-wash and soak the stainless steel cavity in sequence, and rinse it again. Step S3: After the second rinsing is completed, the stainless steel cavity is subjected to a second ultrasonic cleaning at a second predetermined ultrasonic frequency, a second predetermined power density, a second predetermined cleaning time, and a second predetermined cleaning temperature, and then the stainless steel cavity is rinsed. Step S4: After rinsing, the stainless steel is first immersed at a first predetermined temperature and a first predetermined time, and then the stainless steel cavity is second immersed at a second predetermined temperature and a second predetermined time. After that, the stainless steel cavity is dried and hung up.

2. The ultrasonic cleaning method for the stainless steel cavity of the ion implanter according to claim 1, characterized in that, In step S2, the fine sandpaper includes white corundum sandpaper or brown corundum sandpaper.

3. The ultrasonic cleaning method for the stainless steel cavity of the ion implanter according to claim 1, characterized in that, In step S2, the fine sandpaper has a mesh size of 240 to 400.

4. The ultrasonic cleaning method for the stainless steel cavity of the ion implanter according to claim 1, characterized in that, In step S2, during the grinding of the stainless steel cavity using fine sandpaper of different grits, the number of sheets of fine sandpaper used per unit area of ​​the stainless steel cavity varies from 10 to 20.

5. The ultrasonic cleaning method for the stainless steel cavity of the ion implanter according to claim 1, characterized in that, In step S1: The first predetermined ultrasonic frequency includes 20kHz to 40kHz; The first predetermined power density includes 0.3 W / cm². 2 ; The first scheduled cleaning time includes 5 to 10 minutes; The first predetermined cleaning temperature ranges from 20℃ to 40℃.

6. The ultrasonic cleaning method for the stainless steel cavity of the ion implanter according to claim 1, characterized in that, In step S3: The second predetermined ultrasonic frequency includes 40kHz to 80kHz; The second predetermined power density includes 0.5 W / cm². 2 ; The second scheduled cleaning time includes 10 to 20 minutes; The second predetermined cleaning temperature ranges from 20°C to 40°C.

7. The ultrasonic cleaning method for the stainless steel cavity of the ion implanter according to claim 1, characterized in that, In step S4, the first predetermined temperature includes 20°C to 25°C; and / or, the first predetermined time includes 5 min to 10 min.

8. The ultrasonic cleaning method for the stainless steel cavity of the ion implanter according to claim 1, characterized in that, In step S4, the second predetermined temperature includes 35°C to 45°C; and / or, the second predetermined time includes 10 min to 20 min.

9. The ultrasonic cleaning method for the stainless steel cavity of the ion implanter according to claim 1, characterized in that, In steps S1 and S2, the stainless steel cavity is placed in a pre-washing tank for pre-washing and soaking, and the pre-washing tank is equipped with a ventilation device for ventilating the pre-washing tank.

10. The ultrasonic cleaning method for the stainless steel cavity of the ion implanter according to any one of claims 1 to 9, characterized in that, The ultrasonic cleaning solution comprises: a degreasing agent and deionized water, wherein the degreasing agent comprises sodium metasilicate pentahydrate, a surfactant, and sodium gluconate; and / or, The volume fraction of the degreasing agent is 1% to 3%.

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