Application of micro-nano bubbles to workpiece cleaning

Abstract

The application discloses application of micro-nano bubbles in workpiece cleaning and relates to the technical field of precision workpiece cleaning. Pure water is used as the only basic medium, the strong oxidation effect of hydroxyl radicals generated by the shrinkage and breakage of the micro-nano bubbles and the surface negative potential adsorption characteristics are utilized, and a three-stage segmented special cleaning process is used, so that the 0.2-1 micron superfine particles, organic matters, metal pollutants, photoresist and other impurities on the surface of the precision workpiece are efficiently removed. The application discloses a precision workpiece cleaning method, which discards the mode of a large number of chemical agents, high-temperature processing and multi-process complex operation in the traditional cleaning process, can be suitable for cleaning of multiple types of precision workpieces such as semiconductor wafers, 3C precision components, new energy aluminum shells, photovoltaic silicon wafers and optical lenses, has the advantages of no workpiece damage, normal-temperature and low-temperature operation, process simplification, energy saving and environmental protection, cost reduction and efficiency improvement, and effectively solves the problems of micro-particle residue, workpiece damage and serious pollution existing in the traditional ultrasonic cleaning and agent cleaning.

Description

Technical Field

[0001] This invention relates to the field of precision workpiece cleaning technology, and in particular to the application of micro-nano bubbles in workpiece cleaning. Background Technology

[0002] Currently, the mainstream cleaning processes for precision workpieces in the industry are a combination of ultrasonic cleaning, megasonic cleaning, chemical cleaning, and brush contact cleaning. However, traditional cleaning processes are not precise enough to remove impurities such as 0.2μm-1μm ultrafine aluminum powder, grinding particles, photoresist residue, organic oil, and trace metal contamination from the surface of precision workpieces. This can easily lead to microparticle residue problems, which seriously affect the yield of workpieces.

[0003] Traditional chemical cleaning relies on highly corrosive agents such as sulfuric acid, hydrogen peroxide, hydrochloric acid, and ammonium hydroxide. This not only results in extremely high costs for agent procurement and hazardous waste disposal but also causes water and environmental pollution. Furthermore, traditional chemical cleaning requires high-temperature processes, which can easily lead to deformation and material damage in precision workpieces, affecting their performance. Traditional ultrasonic and brush-based contact cleaning methods suffer from uneven physical impact, which can easily scratch the surface of precision workpieces and are extremely ineffective at removing ultrafine contaminants from the pores of the workpieces. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing traditional workpiece cleaning technologies, such as low cleaning accuracy, easy damage to workpieces, high energy consumption, large pollution, high cost, and cumbersome procedures. It provides an application solution for micro-nano bubbles in workpiece cleaning, which can achieve efficient removal of ultrafine contaminants from precision workpieces, zero-damage cleaning, green and low-consumption cleaning, and simplified procedures. At the same time, it can be adapted to the rapid transformation of existing production lines, which can significantly reduce the production and maintenance costs of enterprises.

[0005] This application provides an application of micro / nano bubbles in workpiece cleaning. Micro / nano bubbles are used in conjunction with a three-stage segmented cleaning process to clean precision workpieces, using pure water as the medium and without the addition of chemical agents. The specific steps include: S1. Main cleaning treatment: The workpiece to be cleaned is placed in the first cleaning tank and cleaned by a combination of ultrasonic waves and micro-nano bubbles. The penetration and peeling properties of micro-nano bubbles are used to remove 0.2-1μm ultrafine particulate contaminants from the pores of the workpiece. S2. Overflow rinsing treatment: After the main wash, the workpiece is transferred to the second cleaning tank and rinsed with flowing pure water overflow to continuously wash away suspended particles on the surface of the workpiece and avoid secondary adsorption of pollutants. S3. Final washing and dehydration treatment: The rinsed workpiece is transferred to the third cleaning tank, where high-pressure, low-flow pure water spraying is combined with a rapid lifting dehydration process to eliminate the water film on the surface of the workpiece and prevent residual powder after drying. The micro-nano bubbles are prepared using the principle of pressurized dissolution-depressurized foaming, with a bubble density of ≥4000 bubbles / ml and a constant pH of 7 in the pure water medium.

[0006] Furthermore, the micro-nano bubbles are prepared in a controllable manner, and can be prepared by matching single or combined gases such as oxygen, nitrogen, and ozone according to the type of contaminants on the workpiece, thereby achieving differentiated contaminant cleaning.

[0007] Furthermore, the micro-nano bubbles carry a negative potential in pure water, and generate ultra-high internal pressure based on the Yang-Laplace equation during the contraction process. Upon rupture, they release hydroxyl radicals, which have an oxidation-reduction potential of 2.85 eV, enabling strong oxidative decomposition and removal of organic matter, metal impurities, and photoresist contaminants.

[0008] Furthermore, the cleaning temperature of the first cleaning tank is 20℃-55℃, and the entire process can be carried out at room temperature or low temperature.

[0009] Furthermore, the second cleaning tank maintains a dynamic overflow of pure water throughout the entire process, with no stagnant water immersion conditions, and a water circulation rate of 2-10L / min, enabling the recycling and reuse of water resources.

[0010] Furthermore, the three-stage segmented cleaning process can be directly adapted to traditional cleaning production lines. It can be modified simply by installing a high-density MNB generator on existing equipment. Tanks 1 and 2 share one MNB generator, and tanks 3 and 4 share one MNB generator.

[0011] Furthermore, the applicable cleaning workpieces include semiconductor wafers, photovoltaic silicon wafers, optical lenses, 3C electronic product casings, mobile phone lenses, new energy battery aluminum casings, PCBA boards, and precision machined components.

[0012] Furthermore, this applies to processes such as resist stripping, metal contamination removal, and ultrafine particle removal on semiconductor wafers.

[0013] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: 1. High cleaning precision and excellent cleaning effect: It can thoroughly remove contaminants such as 0.2μm-1μm ultrafine particles, photoresist, organic oil stains, and trace metal contamination that are difficult to remove by traditional processes from the pores of workpieces. After cleaning, the workpieces have no micro powder residue and no watermark defects, and the yield rate is greatly improved.

[0014] 2. Zero damage throughout the process and wide adaptability: The pH value of the pure water medium is constant at 7, which is neutral and has no chemical corrosion; no high-intensity physical impact is required, and it can be operated at room temperature and low temperature. It will not cause deformation, scratches or corrosion damage to precision workpieces of various materials. It is suitable for precision workpieces in the semiconductor, 3C, new energy, photovoltaic and optical fields. Detailed Implementation

[0015] To facilitate understanding of the present invention, a more comprehensive description of this application will be provided below; however, the present invention may be implemented in many different forms and is not limited to the embodiments described herein; rather, these embodiments are provided so that the disclosure of the present invention may be more thorough and complete.

[0016] It should be noted that the terms "vertical," "horizontal," "up," "down," "left," "right," and similar expressions used in this article are for illustrative purposes only and do not represent the only possible implementation.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0018] This application proposes an application of micro-nano bubbles in workpiece cleaning. Pure water is used as the only cleaning medium, without any chemical agents added. Standard micro-nano bubbles are prepared based on the principle of pressure dissolution and decompression foaming. Combined with a three-stage segmented cleaning process, standardized cleaning of precision workpieces is completed. It is suitable for various precision metal, glass, and plastic workpieces containing 0.2-1μm pore particles. S1. First Cleaning Tank: Ultrasonic and Micro / Nano Bubble Main Wash: The precision workpiece to be cleaned is stably placed into the first cleaning tank. The ultrasonic and micro / nano bubble working mode is activated, with the ultrasonic power matched to the standard parameters of the precision workpiece. The cleaning time is 6 minutes. Utilizing the strong penetration, cavitation, and peeling properties of high-density micro / nano bubbles, the bubbles penetrate deep into the micropores, gaps, and uneven structures of the workpiece, gradually loosening and peeling off embedded 0.2μm-1μm ultrafine particulate contaminants. Stubborn impurities embedded on the workpiece surface are completely loosened and peeled off into the water, achieving a clean workpiece substrate with only suspended free particles remaining.

[0019] S2. Second Tank Flowing Pure Water Overflow Rinsing Treatment: After the main wash, the workpiece is smoothly transferred to the second cleaning tank. The pure water dynamic overflow circulation system is activated throughout the process, strictly maintaining a flowing water condition and preventing stagnant water immersion. The water circulation rate is stably controlled at 5L / min. The continuously flowing pure water removes suspended ultrafine particles carried from the workpiece surface from the main wash tank in real time, completely preventing secondary adsorption and deposition of micro-particle contaminants, locking in the clean substrate state after the main wash, and preventing workpiece re-contamination from the source of the process.

[0020] S3. Third Tank Pure Water Spraying and Rapid Lifting Dehydration Final Washing: After overflow rinsing, the workpiece is transferred to the third cleaning tank. High-pressure, low-flow pure water is used to precisely spray the entire surface of the workpiece. The spraying pressure is stable and controllable, covering all structural surfaces of the workpiece. After spraying, the equipment's rapid lifting mechanism is activated, and the workpiece is lifted off the water surface at a uniform speed, quickly completing the overall dehydration. This process can completely eliminate the water film on the workpiece surface, avoiding residual traces of micro-powder and watermarks during the pure water drying process, thus forming a final clean and protective effect.

[0021] Preferably, the cleaning medium is room temperature pure deionized water, and the pH value of the medium is kept constant at 7.0 throughout the process. During the pressurization and dissolution stage, the pure deionized water is pressurized to 0.35MPa-0.5MPa to fully dissolve the air in the water. Then, it is injected into the cleaning chamber through the pressure relief nozzle to prepare micro-nano bubbles with a particle size concentrated in the range of 50nm-500nm.

[0022] Preferably, the micro-nano bubble generating equipment adopts a pressurized dissolution and depressurized foaming structure, with a stable output bubble density of greater than or equal to 4000 bubbles / ml and a bubble particle size distribution range of 10nm to 40μm; the complete cleaning equipment includes a three-stage cleaning tank, equipped with an ultrasonic module, a live water overflow circulation system, a high-pressure low-flow spray module, and a workpiece rapid lifting and dehydration mechanism.

[0023] Preferably, the micro-nano bubble generator is a modular device integrated on the outside of the cleaning tank cavity. It is directly connected to the pressure relief nozzle inside the tank through pipelines, and can be directly adapted to existing conventional tank cleaning equipment without the need for large-scale modifications to the original equipment cavity structure.

[0024] Preferably, the cleaning environment is at room temperature (20℃-25℃), a typical cleanroom environment, without the need for high-temperature heating.

[0025] Example 2: For 8 / 12-inch semiconductor wafers in the semiconductor manufacturing field, this invention focuses on three core process challenges: residual photoresist removal, removal of trace metal contamination on the surface, and removal of 0.2μm-1μm ultrafine abrasive particles. Batch cleaning control experiments were conducted, and the micro-nano bubble composite cleaning process of this invention was adopted to completely replace the traditional high-temperature multi-agent cleaning process. The test environment was a semiconductor cleanroom, and the cleaning medium was ultrapure water.

[0026] The original traditional process uses a four-stage high-temperature chemical cleaning process. The first step involves immersing the photoresist in a mixture of concentrated sulfuric acid and hydrogen peroxide at 120°C for 8 to 10 minutes. The second step involves removing metal contamination with a mixture of hydrochloric acid and hydrogen peroxide at 80°C for 6 to 8 minutes. The third step involves rinsing with ultrapure water at 80°C. The fourth step is a final rinse with ultrapure water at room temperature. The entire process requires two dedicated cleaning devices. This process has significant drawbacks: the high-temperature strong acid solution can easily cause slight corrosion to the surface structure of the wafer, there is a high risk of chemical residue, and a large amount of acidic hazardous waste is generated, resulting in high subsequent treatment costs.

[0027] This embodiment uses ozone and oxygen composite functional micro-nano bubbles. The specific process is as follows: First, the composite micro-nano bubbles work together with ultrasonic main cleaning for 7 to 8 minutes. The photoresist is completely decomposed and metal ions and ultrafine particles are stripped away by the strong oxidizing effect of hydroxyl radicals.

[0028] The second step is room temperature dynamic overflow ultrapure water rinsing, with a rinsing time of 4 to 6 minutes and a water circulation rate of 5L / min. This can prevent secondary adsorption of pollutants, and only one cleaning device is needed to complete the entire process.

[0029] Preferably, the micro-nano bubble particle size is controlled between 10μm and 30μm, the ozone injection rate is controlled between 0.8L / min and 1.2L / min, and the gas injection rate after mixing oxygen and ozone is maintained between 1.5L / min and 2.0L / min. Under these parameters, the concentration of hydroxyl radicals generated is stable, and the oxidation decomposition efficiency is the highest. This ensures the cleaning effect on photoresist and contaminants, and prevents damage to the wafer surface structure due to excessively large bubble particle size or excessively fast gas injection rate, thus avoiding additional surface damage problems.

[0030] Preferably, the overall process temperature is kept constant at 60℃, and the total power of the cleaning equipment is 3kW. This can accelerate the oxidation reaction rate of hydroxyl radicals, improve the efficiency of photoresist decomposition and contaminant removal, and avoid accelerating ozone decomposition due to excessive temperature, which would lead to a decrease in the concentration of hydroxyl radicals. At the same time, the energy consumption of the equipment is within a reasonable range under this power condition, which can achieve a balance between cleaning effect and production cost, and is suitable for the production needs of industrial batch wafer cleaning.

[0031] Preferably, the bubble density is stably maintained at 4200-4500 bubbles / ml. Within this density range, the micro- and nano-bubbles are evenly distributed in the cleaning solution. This provides sufficient reaction sites for hydroxyl radicals, ensuring that all areas of the wafer surface are fully oxidized and cleaned, avoiding problems such as local photoresist residue or incomplete removal of contaminants. At the same time, it prevents bubble agglomeration due to excessive bubble density, which would reduce the homogeneity of the cleaning solution and affect the final cleaning stability.

[0032] Preferably, the ultrasonic main cleaning time for composite micro-nano bubbles is 7.5 minutes. This time setting can ensure that contaminants such as photoresist and particle residues are fully oxidized and removed, without causing etching damage to the wafer surface due to excessive main cleaning time. At the same time, it shortens the overall process time, increases the wafer cleaning capacity per unit time, and meets the efficiency requirements of industrial production.

[0033] Preferably, the room temperature dynamic overflow ultrapure water rinsing time is 5 minutes. This duration can fully replace the impurities containing cleaning agents adsorbed on the wafer surface, avoid the impact of agent residue on subsequent wafer processing performance, and at the same time, it will not consume ultrapure water due to excessive rinsing time, effectively control water resource costs, and meet the requirements of mass production.

[0034] Example 3: To address industry challenges such as residual silicon powder after N-type and P-type photovoltaic silicon wafer slicing, as well as surface organic residues and micropore impurities after HJT cell texturing, mass production adaptation tests were conducted. The test subjects were mainstream 182mm and 210mm photovoltaic silicon wafers, and the cleaning environment was a photovoltaic dust-free production workshop. The performance differences between the traditional warm water chemical cleaning process and the room temperature micro-nano bubble cleaning process of this invention were compared.

[0035] Traditional processes require soaking in 80°C constant-temperature hot water with a special alkaline cleaning agent. This results in a large consumption of cleaning agent per batch, and the high-temperature conditions can lead to unevenness in the texturing layer on the silicon wafer surface, incomplete removal of ultrafine silicon powder, and affect the light transmittance of the silicon wafer and the conversion efficiency of the battery.

[0036] This invention uses room-temperature ultrapure water as the medium, combined with high-purity oxygen micro-nano bubbles for full-area cleaning. The negative potential of the bubble surface precisely adsorbs 0.3μm-1μm ultrafine silicon powder on the silicon wafer surface, and hydroxyl radicals oxidize and decompose residual organic impurities from texturing. The complete process consists of three steps: The first step is micro-nano bubble immersion activation, which takes 3 to 5 minutes. The silicon wafer is completely immersed in room temperature ultrapure water containing dissolved oxygen micro-nano bubbles. The micro-nano bubbles are evenly attached to the entire surface of the silicon wafer with the water flow. The electrostatic effect loosens the ultrafine silicon powder and organic impurities on the surface of the silicon wafer, thus completing the pre-separation of impurities.

[0037] The second step is full-area negative pressure oscillation stripping. The pulse negative pressure device at the bottom of the cleaning tank is turned on, which drives the micro-nano bubbles to generate high-frequency oscillation, so that the pre-separated silicon powder and impurities are completely stripped from the silicon wafer surface and enter the cleaning water. This step takes 2 to 4 minutes.

[0038] The third step is overflow rinsing to remove impurities. The micro-nano bubble water is slowly overflowed and flows to remove the water carrying impurities from the cleaning tank. At the same time, new ultrapure water containing bubbles is added to complete the rinsing, and finally a clean photovoltaic silicon wafer is obtained. This step takes 1 to 3 minutes.

[0039] Preferably, the total power of the entire cleaning process is 3kw, and the entire process is kept at room temperature without the need for additional heating.

[0040] Preferably, the immersion activation time is 4 minutes, which allows micro-nano bubbles to fully adhere to the entire surface of the silicon wafer, ensuring the pre-separation effect of impurities without prolonging the overall process time.

[0041] Preferably, the full-area negative pressure oscillation peeling time is controlled at 3 minutes, which can not only completely peel off impurities, but also prevent damage to the silicon wafer surface due to excessive oscillation.

[0042] Preferably, the overflow cleaning and rinsing time is set to 2 minutes, which can ensure that impurities are completely discharged with the overflow and avoid excessive consumption of water resources.

[0043] Example 4: For mainstream precision components in the 3C industry, including glass mobile phone back covers, high-definition optical lenses, PCB circuit boards, aluminum alloy precision stamping parts, connectors, 3D printed photosensitive resin components, etc., multi-material compatibility cleaning tests were carried out. The contaminants of various components included processing lubricating oil, mold release agent, photosensitive resin residue, dust microparticles, fingerprint oil stains, etc.

[0044] Traditional cleaning methods often use a combination of ultrasonic waves and cleaning agents, which can easily lead to problems such as scratches on the surface of components, incomplete cleaning of resin residue, and dirt accumulation in small pores, making it difficult to guarantee the yield rate.

[0045] This invention employs a gradient micro / nano bubble composite cleaning process, with the complete standardized process sequence and parameters as follows: The first step involves a full-area pre-treatment with 50℃ constant-temperature pure water, with a pre-treatment time of 30 to 45 seconds. This softens stubborn oil stains on the surface. The water pressure is controlled at 0.2 MPa to 0.3 MPa, which can initially remove loose contaminants attached to the surface of the components, reducing the load of subsequent deep cleaning.

[0046] The second step involves constant-temperature immersion using high-purity oxygen micro-nano bubbles, with an oxygen content of 85% to 92% and an average bubble size controlled between 80 nm and 110 μm. The immersion temperature is maintained at 45°C to 50°C, and the immersion time is 2 to 3 minutes. The micro-nano bubbles can utilize their own negative pressure adsorption to carry out loose residual pollutants from the gaps and small pores of the components. At the same time, the oxygen micro-nano bubbles can initially oxidize and decompose stubborn organic oil stains, reducing the adhesion between the oil stains and the surface of the components, without causing scratches to the surface of the components.

[0047] The third step involves using high-pressure, low-flow oxygen micro-nano bubbles for precise spraying, with a spraying time of 1.5 to 2.5 minutes, to completely remove impurities remaining in the pores and gaps of the components.

[0048] The fourth step involves using gentle, low-frequency ultrasonic waves to assist in impurity removal. The auxiliary removal time is 30 to 60 seconds, which can further loosen and peel away the fine impurities remaining deep in the pores. The frequency is controlled in the range of 20 kHz to 28 kHz to avoid high-frequency ultrasonic waves affecting the surface precision of the precision components. Combined with the continuous flow of low-concentration micro-nano bubble water, the detached impurities can be promptly carried out of the component gaps to avoid secondary adhesion.

[0049] The sixth step involves using a dry hot air vortex blowing process. The hot air temperature is set to 65℃ to 75℃, the blowing pressure is controlled at 0.4MPa to 0.5MPa, and the blowing time is 2 to 3 minutes. This can quickly dry the residual moisture on the surface and in the gaps of the components, completing the entire cleaning process.

[0050] Preferably, the high-pressure, low-flow precision spraying has a spraying time of 2 minutes and a spraying pressure of 0.5MPa-3MPa. Through the high-pressure impact combined with the entrainment effect of the water flow, particulate and oil film contaminants attached to the surface of the workpiece are initially removed. At the same time, the low-flow design can avoid excessive waste of water resources and control the energy consumption of the cleaning process while ensuring the initial cleaning effect.

[0051] Preferably, the gentle low-frequency ultrasonic-assisted impurity removal time is 40 seconds and the frequency is 25kHz, which can better balance the impurity removal effect and the protection of precision components. Combined with the continuous introduction of 90% oxygen micro-nano bubble water flow, it can more smoothly carry out the loosened fine impurities deep in the pores of the components, effectively avoiding the secondary adhesion of impurities during the cleaning process and improving the overall cleaning cleanliness.

[0052] Preferably, the hot air temperature is 75℃, the blowing pressure is 0.5MPa, and the blowing time is 2min. This ensures the drying effect while avoiding the impact of excessively high temperatures on the material properties of the components. It is suitable for the cleaning and drying needs of most commonly used precision metal components. Combined with the vortex blowing method, the hot air can fully penetrate into all the gaps of the components, avoiding residual water stains from affecting subsequent processing or use. The final product is a clean, impurity-free component with no damage to its surface precision.

[0053] Example 5: For high-precision optical components such as AR / VR optical lenses, automotive optical lenses, precision glass lenses, and coated optical lenses in the high-end optics industry, this solution addresses precision contamination issues such as coating residue, optical grease, nano-sized dust particles, watermark spots, and fingerprint residue on lens surfaces.

[0054] Optical lenses are ultra-precise light-transmitting devices, and their surfaces cannot tolerate any minor scratches, residual impurities, or light transmission defects. Traditional cleaning processes can easily lead to yield losses, making them a difficult point in the industry.

[0055] Traditional optical lens cleaning generally employs a combination of multiple chemical solutions for soaking, manual wiping, and high-frequency ultrasonic cleaning, which has many drawbacks: chemical agents can easily corrode the anti-reflective coating and other coating layers on the lens, causing the coating to peel off and light transmittance to decrease; the physical impact of high-frequency ultrasonic waves can easily cause micro-cracks in the lens and edge chipping of the coating; manual wiping leaves fiber residue and secondary pollution, and it is not thorough in removing 0.2-1μm ultrafine dust particles embedded in the curved or arc-shaped surfaces of the lens, which can easily lead to defects such as light transmission impurities and poor scattering after cleaning. At the same time, traditional processes use a large amount of chemicals and require water temperatures to be maintained at 55℃-65℃, resulting in high energy consumption and environmental costs.

[0056] This embodiment employs a three-stage segmented micro / nano bubble cleaning process, suitable for the non-destructive cleaning requirements of optical devices. The specific cleaning process is as follows: The first step involves ultrasonic synergistic micro-nano bubble primary cleaning in the first tank for 5 to 6 minutes. Relying on the Brownian motion of micro-nano bubbles, the lens surface and microporous structure are penetrated, slowly peeling off the surface-cured optical grease, coating debris and ultrafine dust particles. The flexible cavitation effect will not damage the coating and the lens substrate.

[0057] The second step involves rinsing with pure water in the second tank for 3.5 to 4.5 minutes at a flow rate of 4.5 L / min. This process continuously removes dust and desorbed grease residue that were suspended on the lens surface after being peeled off in the first tank. The dynamic overflow process prevents secondary adhesion of contaminants.

[0058] The third step involves high-pressure, low-flow-rate precise spraying and rapid lifting dehydration in the third tank. This process uses high-pressure, low-flow-rate water to remove trace amounts of residual floating water and fine suspended matter from the lens surface. During the rapid lifting process, the lens surface is dehydrated without watermarks due to the inertial peeling effect of the water flow and surface tension. After cleaning, the lens is dried at a low temperature of 75°C without airflow for 8 to 10 minutes, with an optimal drying time of 8.5 minutes. This process avoids thermal deformation of the lens and the precipitation of water stains, ultimately resulting in a clean optical lens free of watermarks and residual impurities.

[0059] Preferably, the ultrasonic-assisted micro-nano bubble main wash time is 5.5 minutes, which can minimize the overall cleaning time of a single batch of lenses while ensuring the removal of stains, thereby improving the processing efficiency of the equipment.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can have various modifications and variations. 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 application of micro / nanobubbles in workpiece cleaning, characterized in that, Precision workpieces are cleaned using a micro-nano bubble combined with a three-stage segmented cleaning process, with pure water as the medium and no chemical agents added. The specific steps include: S1. Main cleaning treatment: The workpiece to be cleaned is placed in the first cleaning tank and cleaned by a combination of ultrasonic waves and micro-nano bubbles. The penetration and peeling properties of micro-nano bubbles are used to remove 0.2-1μm ultrafine particulate contaminants from the pores of the workpiece. S2. Overflow rinsing treatment: After the main wash, the workpiece is transferred to the second cleaning tank and rinsed with flowing pure water overflow to continuously wash away suspended particles on the surface of the workpiece and avoid secondary adsorption of pollutants. S3. Final washing and dehydration treatment: The rinsed workpiece is transferred to the third cleaning tank, where high-pressure, low-flow pure water spraying is combined with a rapid lifting dehydration process to eliminate the water film on the surface of the workpiece and prevent residual powder after drying. The micro-nano bubbles are prepared using the principle of pressurized dissolution-depressurized foaming, with a bubble density of ≥4000 bubbles / ml and a constant pH of 7 in the pure water medium.

2. The application of micro / nano bubbles in workpiece cleaning according to claim 1, characterized in that, The micro-nano bubbles are prepared in a controllable manner, and can be prepared by matching single or combined gases such as oxygen, nitrogen, and ozone according to the type of contaminants on the workpiece, thereby achieving differentiated contaminant cleaning.

3. The application of micro / nano bubbles in workpiece cleaning according to claim 1, characterized in that, The micro-nano bubbles carry a negative potential in pure water. During the contraction process, they generate ultra-high internal pressure based on the Yang-Laplace equation. Upon rupture, they release hydroxyl radicals. The oxidation-reduction potential of the hydroxyl radicals reaches 2.85 eV, which can strongly oxidize and decompose organic matter, metal impurities, and photoresist contaminants.

4. The application of micro / nano bubbles in workpiece cleaning according to claim 1, characterized in that, The cleaning temperature of the first cleaning tank is 20℃-55℃, and the entire process can be carried out at room temperature or low temperature.

5. The application of micro / nano bubbles in workpiece cleaning according to claim 1, characterized in that, The second cleaning tank maintains a dynamic overflow of pure water throughout the process, with no stagnant water immersion. The water circulation rate is 2-10L / min, which enables the recycling and reuse of water resources.

6. The application of micro / nano bubbles in workpiece cleaning according to claim 1, characterized in that, The three-stage segmented cleaning process can be directly adapted to traditional cleaning production lines. It can be modified simply by installing a high-density MNB generator on the existing equipment. Tanks 1 and 2 share one MNB generator, and tanks 3 and 4 share one MNB generator.

7. The application of micro / nano bubbles in workpiece cleaning according to claim 1, characterized in that, Applicable cleaning workpieces include semiconductor wafers, photovoltaic silicon wafers, optical lenses, 3C electronic product casings, mobile phone lenses, new energy battery aluminum casings, PCBA boards, and precision machined components.

8. The application of micro / nano bubbles in workpiece cleaning according to claim 1, characterized in that, This technology is designed for processes involving resist stripping, metal contamination removal, and ultrafine particle removal on semiconductor wafers.