Integrated resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in semiconductor manufacturing processes.

Abstract

This invention proposes a comprehensive resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in semiconductor manufacturing processes. Under conditions where no chemical reagents are added, solid-liquid separation is performed sequentially through a dynamic ceramic membrane filtration system and a convergent filter. After the resulting clarified liquid passes inspection, it is purified through a UF system and / or RO (reverse osmosis) filtration system to realize the recovery and utilization of semiconductor manufacturing wastewater. Furthermore, the invention proposes a method for manufacturing the ceramic membrane used in this process. The ceramic membrane has hydrophilicity due to its titanium oxide content, high bending hardness due to its zirconia content, excellent wear resistance, and surface coating modification provides strong stain resistance, is less prone to clogging, has high precision, and high mechanical strength. This process directly separates solid and liquid phases and simultaneously recovers the solid-liquid two phases. The recovered semiconductor fine particles do not contain other impurities or chemical residues. They are directly vacuum-dehydrated and dried in the convergent filter and bagged, making them advantageous for recovery and utilization, convenient for transportation, and achieving a wastewater recovery rate of over 97% and a semiconductor fine particle recovery rate of over 98%.

Description

Technical Field

[0001] The present invention relates to the technical field of waste liquid treatment in the processing process of semiconductor industry wafer materials, and particularly relates to the comprehensive recycling and utilization process of wafer cutting, grinding, and polishing wastewater in the semiconductor manufacturing process.

Background Art

[0002] In the semiconductor product manufacturing industry, in the processing processes such as cutting, polishing, and buffing of wafers or wafer materials, high-purity water is used as the base water in the production process, and a large amount of high-purity water needs to be consumed throughout the manufacturing process. In the process of subtractive manufacturing such as cutting, polishing, and buffing, a part of the semiconductor material (mainly wafers and chips) is removed, and these materials are often distributed in high-purity water in the form of fine particle powder. There are few other impurities in such water. High-purity water and the fine particle powder of semiconductor materials are both resource-based products with high value. In order to maintain and realize their value, it is necessary to separate and reuse them using a resource-based treatment process that does not use any chemical agents.

[0003] Currently, wastewater from cutting, polishing, and buffing semiconductor wafer / chip materials contains large amounts of semiconductor material fine powder. Depending on the type of semiconductor material, there are Si, Ce, CdTe, GaAsP, etc., and depending on the process, the particle size is distributed between nanometers, subnanometers, and microns. Among these, nanometer and submicron-sized particulate semiconductor material fine powders have high surface energy, so they form a stable solid-liquid mixture with water, maintaining a stable state for a long period of time without settling or agglomerating. Common methods involve using chemical agents to break stabilization, agglomerate, coagulate, and separate solid and liquid, but these methods cannot recycle the clean water and semiconductor material fine powder. For example, Chinese Patent No. CN20110648428.X discloses a method for treating semiconductor polishing wastewater, which uses a method of adding chemical reagents (coagulants, coagulation aids) to perform sedimentation treatment. Furthermore, Chinese Patent No. CN20110730408.7 discloses a method for treating semiconductor wastewater that employs a similar method of adding chemical reagents to first agglomerate suspended matter, and then uses a filtration separation device to perform solid-liquid separation and treat the wastewater. However, these methods consume large amounts of chemical reagents, cannot be reprocessed, and the resulting semiconductor material fine powder and water cannot be reused, resulting in secondary pollution.

[0004] Furthermore, some people treat these wastewaters directly using filters, which allows for multi-stage filtration and prevents secondary pollution. However, the flow is too long, the filtration accuracy is insufficient, the processing capacity is limited, and it is difficult to collect semiconductor material fine powders in a concentrated manner. For example, Chinese patent No. CN 2016214221971.4 discloses a wastewater reuse device for polishing and cutting in the semiconductor industry, which uses multiple sets of equipment to perform multiple filtration processes. However, the overall process line of the treatment device is too long, the processing capacity is unstable, and it is difficult for the system to operate stably and continuously.

[0005] When selecting a filtration system, commonly used filter elements include hollow fiber membranes or tubular ceramic membranes. While hollow fiber membranes and tubular ceramic membranes offer high filtration accuracy, the filter elements themselves remain stationary during operation. In actual construction applications, wastewater containing fine semiconductor material powders, colloidal particles, and angular particulate matter can lead to a rapid drop in the stationary membrane filtration flux, severe membrane contamination, or damage. This makes the membrane prone to clogging, requiring frequent cleaning, consuming large amounts of chemicals, and the cleaning wastewater becomes recovered wastewater, resulting in a low water recovery rate and inability to recover the fine semiconductor material powders.

[0006] Therefore, improving filter elements is key to solving these problems. For example, Chinese patent CN2011170407.3 discloses a batch complete filtration technology for API drug solutions in the pre-crystallization process during pharmaceutical production, and mentions filtering fine particles using a rotating ceramic membrane. Compared to tubular static ceramic membranes, it is expected to have superior effects in terms of being less prone to clogging and maintaining a stable flux. However, when used with wastewater containing hard semiconductor material fine powders or angular particulate matter, the membrane surface is easily abraded and damaged, filtration accuracy is easily lost, and proper filtration is not possible. Furthermore, when used with ultrafine powders and colloidal contamination with particle sizes distributed between 5 nm and 60 nm, the membrane surface becomes clogged with membrane pores, the flux drops rapidly, and the processing system cannot operate continuously and stably, resulting in low recovery rates of clean water and semiconductor material fine powders.

[0007] Therefore, it is necessary to improve the wastewater treatment methods used in conventional semiconductor manufacturing processes to solve the above problems. [Overview of the Initiative] [Means for solving the problem]

[0008] The objective of this invention is to maintain the cleanliness of semiconductor material nanoparticles without using any chemical agents, to achieve nanometer-level high-precision solid-liquid separation using a dynamic ceramic membrane filtration system, and to perform on-site dewatering and drying treatment using a convergent filter, thereby intensively recovering semiconductor material nanoparticles and water resources.

[0009] To achieve the above objective, the present invention proposes an integrated resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in semiconductor manufacturing processes. Step (1) involves performing solid-liquid separation treatment on wastewater from wafer cutting, grinding, and polishing in the semiconductor manufacturing process through a dynamic ceramic membrane filtration system. The resulting clarified liquid, after passing detection, enters a clean water tank for further treatment. If it fails, the solid-liquid separation treatment is repeated, and the resulting concentrated liquid enters a concentrated liquid tank. Step (2) involves performing a secondary solid-liquid separation treatment on the concentrated liquid from step (1) through a convergent filter, where fine particles accumulate on the surface of the filter element of the convergent filter to form a cake layer, and the permeate is returned to a dynamic ceramic membrane filtration system for recirculation treatment. Step (3) involves, after multiple circulation processes, all of the concentrated liquid generated by the dynamic ceramic membrane filtration system is placed into a convergent filter for final solid-liquid separation, and the cake layer is subjected to on-site dewatering and drying until its moisture content is 30% or less, followed by an automated slag discharge operation to recover the fine particles. Step (1) involves purifying the water in the fresh water tank through an ultrafiltration system and / or an RO (reverse osmosis) filtration system, collecting ultrapure water for use, and then, step (4) involves returning the concentrated water produced by the RO (reverse osmosis) filtration system to a dynamic ceramic membrane filtration system for circulation treatment, ultimately achieving solid-liquid separation. Here, the filter element of the dynamic ceramic membrane filtration system is a ceramic membrane, and the separation layer of the ceramic membrane has hydrophilicity due to the inclusion of titanium oxide and high bending hardness due to the inclusion of zirconia. The surface of the filter element of the aforementioned convergent filter is covered with a nanofiber film, which improves the solid-liquid separation efficiency of the convergent filter and reduces the moisture content of the cake layer.

[0010] In some embodiments, the clarified liquid produced from the dynamic ceramic membrane filtration system in step (1) is entered into a fresh water tank for treatment if the measured turbidity is less than 0.3 NTU.

[0011] In some embodiments, the components of the fine particles are one of the following: Si, Ce, SiC, CdTe, GaAs, InP, CdS, GaAlAs, and GaAsP.

[0012] In some embodiments, the operating pressure of the dynamic ceramic membrane filtration system is 0.01 to 0.2 MPa, the ceramic membrane has a filtration accuracy of 5 to 200 nm, and a rotation speed of 50 to 500 Hz.

[0013] In some embodiments, the operating pressure of the convergent filter is 0.2 to 1 MPa, and the filtration accuracy of the filter element of the convergent filter is 0.2 to 1 μm.

[0014] In some embodiments, the wastewater from step (1) is first subjected to ultrasonic pretreatment, and then filtered and separated through a dynamic ceramic membrane filtration system.

[0015] In some embodiments, the ultrasonic treatment has a frequency of 20 to 60 kHz and an intensity of 2.0 to 10.0 kW.

[0016] In some embodiments, if the median diameter D(50) of the fine particles in the wastewater is less than 50 nm, ultrasonic pretreatment is performed.

[0017] To achieve the above objective, the present invention further provides a comprehensive resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in semiconductor manufacturing processes. Step (1) involves performing solid-liquid separation treatment on wastewater from wafer cutting, grinding, and polishing in the semiconductor manufacturing process, passing it through a first convergent filter, depositing fine particles on the surface of the filter element of the first convergent filter to form a cake layer, and then processing the permeate in a dynamic ceramic membrane filtration system. Step (2) involves the following steps: the clarified liquid processed in the dynamic ceramic membrane filtration system, after passing detection, enters the clean water tank for further processing; if it does not pass, it enters the first convergent filter for reprocessing, and the resulting concentrated liquid is returned to the first convergent filter; Step (3) involves circulating the liquid multiple times, then placing all the concentrated liquid generated by the dynamic ceramic membrane filtration system into the first convergent filter for final solid-liquid separation, performing on-site dewatering and drying of the cake layer until its moisture content is 30% or less, performing an automated slag discharge, and recovering the fine particles. Step (2) involves purifying the water in the clean water tank through an ultrafiltration system and / or an RO (reverse osmosis) filtration system, collecting ultrapure water for use, and then recirculating the concentrated water produced by the RO (reverse osmosis) filtration system back to the first convergent filter for further treatment, ultimately achieving solid-liquid separation. Here, the filter element of the dynamic ceramic membrane filtration system is a ceramic membrane, and the separation layer of the ceramic membrane has hydrophilicity due to the inclusion of titanium oxide and high bending hardness due to the inclusion of zirconia. The surface of the filter element of the first convergent filter is covered with a nanofiber film, which improves the solid-liquid separation efficiency of the first convergent filter and reduces the moisture content of the cake layer.

[0018] In some embodiments, a second convergent filter is connected to the concentrated liquid outlet of the first convergent filter, the processing capacity of the first convergent filter is higher than that of the second convergent filter, the concentrated liquid from the first convergent filter in step (3) enters the second convergent filter, and the cake layer is subjected to on-site dewatering and drying until the moisture content of the cake layer is 30% or less, an automatic slag discharge operation is performed, and fine particles are recovered.

[0019] In some embodiments, if the particle size of the fine particles in the wastewater is less than 1 μm, the process described in claim 1 is employed.

[0020] In some embodiments, when the particle size of the fine particles in the wastewater is 1 μm or larger, the process described in claim 9 is employed.

[0021] Another object of the present invention is to disclose a method for manufacturing a ceramic membrane manufactured as a filter element of a dynamic ceramic membrane filtration system, which has high precision, high film surface hardness, low surface roughness, the film layer has a longer service life and better anti-fouling performance, and can be applied to the wastewater treatment of high hardness, super wear-resistant, and ultrafine powder semiconductors.

[0022] To achieve the above object, the present invention provides a method for manufacturing a ceramic membrane used for the comprehensive recycling and utilization of the resources of wafer cutting, grinding, and polishing wastewater in the semiconductor manufacturing process. Mix micron aluminum oxide powder with a sintering aid, a pore-forming agent, a dispersant, and a binder in a certain proportion, grind them in a ball mill for 4 to 6 hours to form a paste, and then go through a spray granulation and dry pressing process to form a support layer blank. After removing the dried moisture, perform a firing treatment to produce a support layer in step (1). Mix micron aluminum oxide powder with a sintering aid, a grinding aid, a dispersant, and a binder in a certain proportion, grind them in a ball mill for 6 to 8 hours to form an intermediate layer film paste. After coating, drying, and firing, form an intermediate layer of the film. Here, the pore diameter of the intermediate layer of the ceramic membrane produced in this step is 0.2 to 2 μm, the roughness Ra is 2.5 to 10 μm, and the Mohs hardness HM is 3 to 4. Step (2) of producing the intermediate layer. After uniformly stirring nanometer aluminum oxide powder with a sintering aid, a binder, and zirconia sol in a certain proportion to form a separation layer paste, and then coating, drying, and firing, form a separation layer of the film. Here, the pore diameter of the separation layer of the ceramic membrane produced in this step is 50 to 80 nm, the roughness Ra is 0.2 to 0.4 μm, and the Mohs hardness HM is 8 to 9. Step (3) of producing the separation layer is included.

[0023] In some embodiments, the median diameter D(50) of the aluminum oxide powder in step (1) is 5 to 30 μm, the median diameter D(50) of the aluminum oxide powder in step (2) is 5 to 10 μm, and the median diameter (50) of the aluminum oxide powder in step (3) is 0.1 to 1 μm.

[0024] In some embodiments, the sintering aid described in step (1) is titanium oxide (0.5 - 1.25 wt%), or silica (2 - 5 wt%), or magnesium oxide (0.5 - 2.5 wt%); the pore-forming agent is one or more of starch (3 - 8 wt%), or carbon powder (1 - 7 wt%), or cellulose (1.5 - 5 wt%); the dispersant is one or two of sodium hexametaphosphate and PEG (2 - 4 wt%); and the binder is a polyvinyl alcohol solution with a concentration of 10 - 15% (2 - 5 wt%).

[0025] In some embodiments, the sintering aid described in step (2) is silica (5 - 10 wt%); the grinding aid is sodium hexametaphosphate (0.5 - 1.5 wt%); the dispersant is PEG (1 - 2 wt%); and the binder is a PVA solution with a concentration of 2 - 5% (0.2 - 0.8 wt%).

[0026] In some embodiments, the sintering aid described in step (3) is titanium oxide (10 - 15 wt%); the binder is a PVA solution with a concentration of 5 - 10% (2 - 5 wt%) and zirconia sol (2 - 10 wt%).

[0027] In some embodiments, the ceramic membrane is a filter element of the dynamic ceramic membrane filtration system.

Advantages of the Invention

[0028] Compared to conventional technology, the beneficial effects of the present invention are: (1) It can directly separate solid and liquid phases and recover both phases simultaneously without adding any chemical reagents or adjusting pH with chemicals. (2) The recovered water has low turbidity, so it does not contain other impurities or chemical residues and can be directly purified as feedwater for UF systems and / or RO (reverse osmosis membrane) filtration systems. The recovered semiconductor nanoparticles do not contain other impurities or chemical residues and can be directly vacuum dehydrated, dried, and bagged without using energy-consuming processes such as evaporation and drying, making them advantageous for recovery and utilization, convenient for transport, with a wastewater recovery rate of 97% or more and a semiconductor nanoparticle recovery rate of 98% or more. (3) The ceramic film has hydrophilicity due to the titanium oxide content, high bending hardness due to the zirconia content, excellent wear resistance, and surface coating modification provides strong stain resistance, is less prone to clogging, has high precision, and has high mechanical strength. [Brief explanation of the drawing]

[0029] [Figure 1] This diagram shows the integrated resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in the semiconductor manufacturing process, as shown in Examples 1 and 2. [Figure 2] This is a diagram illustrating the integrated resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in the semiconductor manufacturing process shown in Example 3. [Figure 3] This is an SEM diagram of the support layer of the ceramic film shown in the present invention. [Figure 4] This is an SEM diagram of the separation layer of the ceramic film shown in the present invention. [Figure 5] This is a pore size distribution diagram of the ceramic film shown in the present invention. [Figure 6] This is a line graph comparing the decrease in permeation flux between the ceramic film shown in the present invention and the ceramic film in the prior art. [Figure 7] This is a comparison diagram of pure water and wastewater treated by the process described in the present invention. [Figure 8] This is a diagram of semiconductor microparticles processed by the process shown in the present invention. [Figure 9] This is a flux monitoring distribution diagram for the dynamic ceramic membrane filtration system shown in the present invention. [Modes for carrying out the invention]

[0030] The present invention will be described in detail below based on the embodiments shown in the drawings, but these embodiments are not limitations to the present invention, and any functional, method, or structural equivalent transformation or substitution performed by those skilled in the art based on these embodiments falls within the scope of the present invention.

[0031] (Example 1) As shown in Figures 1, 3-9, the present invention proposes an integrated resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in semiconductor manufacturing processes. Step (1) involves performing solid-liquid separation treatment on wastewater from wafer cutting, grinding, and polishing in the semiconductor manufacturing process through a dynamic ceramic membrane filtration system. The resulting clarified liquid, after passing detection, enters a clean water tank for further treatment. If it fails, the solid-liquid separation treatment is repeated, and the resulting concentrated liquid enters a concentrated liquid tank. Step (2) involves performing a secondary solid-liquid separation treatment on the concentrated liquid from step (1) through a convergent filter, where fine particles accumulate on the surface of the filter element of the convergent filter to form a cake layer, and the permeate is returned to a dynamic ceramic membrane filtration system for recirculation treatment. Step (3) involves, after multiple circulation processes, all of the concentrated liquid generated by the dynamic ceramic membrane filtration system is placed into a convergent filter for final solid-liquid separation, and the cake layer is subjected to on-site dewatering and drying until its moisture content is 30% or less, followed by an automated slag discharge operation to recover the fine particles. Step (1) involves purifying the water in the fresh water tank through an ultrafiltration system and / or an RO (reverse osmosis) filtration system, collecting ultrapure water for use, and then, step (4) involves returning the concentrated water produced by the RO (reverse osmosis) filtration system to a dynamic ceramic membrane filtration system for circulation treatment, ultimately achieving solid-liquid separation. Here, the filter element of the dynamic ceramic membrane filtration system is a ceramic membrane, and the separation layer of the ceramic membrane has hydrophilicity due to the inclusion of titanium oxide and high bending hardness due to the inclusion of zirconia. The surface of the filter element of the aforementioned convergent filter is covered with a nanofiber film, which improves the solid-liquid separation efficiency of the convergent filter and reduces the moisture content of the cake layer.

[0032] In this embodiment, the clarified liquid produced by the dynamic ceramic membrane filtration system passes water quality testing using an online intelligent measuring instrument (including, but not limited to, a turbidimeter and a conductivity meter), then enters a clean water tank and is used as feedwater for the UF system and / or RO (reverse osmosis) filtration system. If it fails the test, it is returned to the dynamic ceramic membrane filtration system. If the clarified liquid produced from the dynamic ceramic membrane filtration system in step (1) has a measured turbidity of less than 0.3 NTU, it enters a clean water tank and undergoes purification treatment at the backend.

[0033] The components of the fine particles described in this invention are, but are not limited to, Si, Ce, SiC, CdTe, GaAs, InP, CdS, GaAlAs, and GaAsP. Any fine particles generated during the subtractive processing step of a semiconductor manufacturing process can be processed using this process. It is necessary to clarify that the wastewater from the semiconductor manufacturing process contains fine particles of any of the above-mentioned unique components, and if it contains multiple components, it can be recovered. However, further classification and recovery is not possible, so the processing process disclosed in this embodiment is mainly applied to wastewater containing a single component.

[0034] When treating wastewater from the semiconductor manufacturing process using this process, the wastewater generated by cutting, grinding, and polishing during the semiconductor manufacturing process is first collected in a collection tank, where it can be homogenized, buffered, and stabilized. The operating pressure of the dynamic ceramic membrane filtration system is 0.01 to 0.2 MPa, the ceramic membrane has a filtration accuracy of 5 to 200 nm, and its rotation speed is 50 to 500 Hz. The operating pressure of the convergent filter is 0.2 to 1 MPa, and the filtration accuracy of the filter element of the convergent filter is 0.2 to 1 μm. In actual applications, different process parameters are selected and adjusted based on the content of particulate matter in the wastewater from the semiconductor manufacturing process to achieve optimal treatment effects. However, the operating parameters of both the dynamic ceramic membrane filtration system and the convergent filter can be selected within the aforementioned numerical ranges and appropriately selected for the backwashing process of the dynamic ceramic membrane filtration system.

[0035] As shown in Figures 6 and 9, the ceramic membrane described in the present invention has a higher flux and more stable performance compared to conventional ceramic membranes (ceramic membrane disclosed in Chinese Patent No. CN2011170407.3), and the flux reduction is more gradual within a 10-day operating period under similar conditions. In this example, five ceramic membranes are placed in one dynamic ceramic membrane filtration system, and the flux shown in Figure 6 is compared to that of one dynamic ceramic membrane filtration system. As shown in Figure 9, when multiple dynamic ceramic membrane filtration systems are used simultaneously and operated at full load for one day, there is almost no change in flux reduction. As a result, the ceramic membrane manufactured according to the present invention and the dynamic ceramic membrane filtration system in which it is installed have more stable and reliable performance, higher processing capacity, and a longer service life.

[0036] The ceramic membrane in this invention has strong hydrophilicity and high bending hardness, resulting in strong stain resistance, high mechanical strength, higher flux, and greater stability. In the dynamic ceramic membrane filtration system, the solid-liquid separated concentrated liquid enters a convergent filter for secondary solid-liquid separation. Since the surface of the filter element of the convergent filter is covered with a nanofiber membrane, both the pore size and porosity of the nanofiber membrane are higher than those of the filtration medium inside the filter element. As a result, fine particles can rapidly accumulate on the surface of the nanofiber membrane to form a cake layer, and moisture can rapidly permeate through it. By controlling the controller of the convergent filter, the cake layer can be purged with gas and / or washed with clean water in the field. After washing and drying the cake layer, the filtration medium of the filter element is expanded through reverse blowing and / or vibration, causing cracks in the cake layer and enabling automatic slag discharge.

[0037] The wastewater recovery rate after this process is 97% or higher, and the semiconductor fine particle recovery rate is 98% or higher.

[0038] (Example 2) When separating solid and liquid wastewater generated in the semiconductor manufacturing process (including cutting, grinding, and polishing processes), the wastewater can be pretreated and then processed according to the treatment process of Example 1.

[0039] The wastewater from step (1) is first subjected to ultrasonic pretreatment, and then filtered and separated through a dynamic ceramic membrane filtration system. The ultrasonic treatment has a frequency of 20-60 kHz and an intensity of 2.0-10.0 kW.

[0040] Ultrasonic pretreatment of wastewater utilizes the cavitation effect generated when ultrasound propagates through the medium, causing rapid growth and collapse of microbubbles in the solution, generating intense local perturbations, disrupting the stable state of the solid-liquid dispersion phase of the wastewater, agglomerating fine particles, and allowing them to enter a dynamic ceramic membrane filtration system. This forms dynamic cross-flow filtration on the ceramic membrane surface, resulting in higher solid-liquid separation efficiency while simultaneously preventing the accumulation of these fine particles on the ceramic membrane surface.

[0041] The above pretreatment process can be selectively applied depending on the size of the particles in the wastewater. If the median diameter D(50) of the particles in the wastewater is less than 50 nm, ultrasonic pretreatment is performed. It should be explained that when the particles D(50) in the wastewater are less than 50 nm, ultrasonic pretreatment can be used to effectively disrupt their stability, and the wastewater after initial destabilization improves the solid-liquid separation performance of the subsequent dynamic ceramic membrane filtration system. If the particles D(50) in the wastewater are 100 nm or larger, the pretreatment does not significantly affect the solid-liquid separation performance of the subsequent dynamic ceramic membrane filtration system, and the wastewater can be processed directly into the dynamic ceramic membrane filtration system without ultrasonic pretreatment.

[0042] (Example 3) Figure 2 shows a comprehensive resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in the semiconductor manufacturing process, Step (1) involves performing solid-liquid separation treatment on wastewater from wafer cutting, grinding, and polishing in the semiconductor manufacturing process, passing it through a first convergent filter, depositing fine particles on the surface of the filter element of the first convergent filter to form a cake layer, and then processing the permeate in a dynamic ceramic membrane filtration system. Step (2) involves the following steps: After the clarified liquid processed in the dynamic ceramic membrane filtration system passes detection, it enters the clean water tank for further processing; if it does not pass, it enters the first convergent filter for reprocessing, and the resulting concentrated liquid is returned to the first convergent filter; Step (3) involves circulating the liquid multiple times, then placing all the concentrated liquid generated by the dynamic ceramic membrane filtration system into the first convergent filter for final solid-liquid separation, performing on-site dewatering and drying of the cake layer until its moisture content is 30% or less, performing an automated slag discharge, and recovering the fine particles. Step (2) involves purifying the water in the clean water tank through an ultrafiltration system and / or an RO (reverse osmosis) filtration system, collecting ultrapure water for use, and then recirculating the concentrated water produced by the RO (reverse osmosis) filtration system back to the first convergent filter for further treatment, ultimately achieving solid-liquid separation. Here, the filter element of the dynamic ceramic membrane filtration system is a ceramic membrane, and the separation layer of the ceramic membrane has hydrophilicity due to the inclusion of titanium oxide and high bending hardness due to the inclusion of zirconia. The surface of the filter element of the first convergent filter is covered with a nanofiber film, which improves the solid-liquid separation efficiency of the first convergent filter and reduces the moisture content of the cake layer.

[0043] Furthermore, a second convergent filter is connected to the concentrated liquid outlet of the first convergent filter, and the processing capacity of the first convergent filter is higher than that of the second convergent filter. In step (3), the concentrated liquid from the first convergent filter enters the second convergent filter, where the cake layer undergoes on-site dewatering and drying until its moisture content is 30% or less, followed by automatic slag discharge and recovery of fine particles.

[0044] In this embodiment, solid slag collection and solid-liquid separation are performed independently using a first convergent filter + dynamic ceramic membrane filter system. The first convergent filter is mainly used to block most of the solid phase particles in the wastewater, stabilizing the concentration of the clarified liquid output. This reduces the problem in Examples 1 and 2 where wastewater directly enters the dynamic ceramic membrane filter system, causing a rapid decrease in the flux of the ceramic membrane due to increased concentration, and also reduces the risk of mechanical seal wear in the dynamic ceramic membrane filter system due to large particles in the wastewater. The installed second convergent filter is mainly used to collect solid-phase dry slag and can operate intermittently, reducing the operating pressure of the first convergent filter. The first convergent filter is mainly used for solid-liquid separation, eliminating the need for frequent valve opening and closing due to on-site dewatering and reducing valve wear.

[0045] The difference between the Examples and the processes shown in Examples 1 and 2 lies in selecting different processes based on the particle size of the microparticles in the wastewater from wafer cutting, grinding, and polishing in the semiconductor manufacturing process. If the particle size of the microparticles in the wastewater is less than 1 μm, select the process shown in Examples 1 or 2. If the particle size of the microparticles in the wastewater is 1 μm or larger, select the process shown in this Example. In either case, the recovery of microparticles from the wastewater and the purification and reuse of water resources can be effectively addressed.

[0046] The wastewater resource recovery and utilization process described in the present invention is applicable not only to wastewater generated in wafer cutting, polishing, and grinding processes in semiconductor manufacturing, but also to waste liquids containing other fine particles, such as titanium dioxide wastewater and lithium battery powder materials such as lithium iron phosphate. The wastewater resource recovery and utilization process described in the present invention can effectively solve problems such as the difficulty in recovering micro-nanometer-class particulate matter contained in waste liquid and the inability to dry it on-site.

[0047] (Example 4) As shown in Figures 3-9, the present invention further discloses a method for manufacturing a ceramic film, and the ceramic film manufactured by this method has high precision, high film surface hardness, and low surface roughness as a filtration element in a dynamic ceramic film filtration system, the film layer has a longer lifespan and better contamination prevention performance, and can be applied to the wastewater treatment of high hardness, ultra-wear-resistant, ultra-fine semiconductor powders.

[0048] A method for manufacturing a ceramic film used for the comprehensive recovery and utilization of wastewater from wafer cutting, grinding, and polishing in semiconductor manufacturing processes includes the following steps: Step (1) Create a support layer. Micron-sized aluminum oxide powder, sintering aid, pore-forming agent, dispersant, and binder are mixed in a constant proportion and ground to a paste using a ball mill for 4-6 hours. This paste is then subjected to spray granulation and dry pressing processes to form a support layer embryo. After drying and removing moisture, it is subjected to a calcination process. During the calcination process at 200°C to 650°C, substances such as pore-forming agents and binders decompose, and the resulting gases create a porous structure inside and on the surface of the support layer after calcination, improving the performance of the membrane during wastewater filtration. Here, the median diameter D(50) of the aluminum oxide powder is 5 to 30 μm, and each component is mixed in the following proportions: the sintering aid is titanium dioxide (0.5 to 1.25 wt%), or silica (2 to 5 wt%), or magnesium oxide (0.5 to 2.5 wt%); the pore-forming agent is one or more of starch (3 to 8 wt%), or carbon powder (1 to 7% wt%), or cellulose (1.5 to 5 wt%); the dispersant is one or two of sodium hexametaphosphate and PEG (2 to 4 wt%); and the binder is a 10 to 15% concentration polyvinyl alcohol solution (2 to 5 wt%).

[0049] During the sintering process, the sintering aid changes from a solid to a liquid. This liquid-phase sintering promotes the rearrangement of crystal grains and contact between them, further increasing grain boundary mobility, promoting the growth of microcrystal grains, and increasing the strength of the support.

[0050] Step (2) Create the intermediate layer. Micron aluminum oxide powder is mixed with sintering aids, grinding aids, dispersants, and binders in a constant proportion and ground in a ball mill for 6-8 hours to form an intermediate layer paste. After coating, drying, and firing, the intermediate layer of the film is formed. Here, the median diameter D(50) of the aluminum oxide powder described in step (2) above is 5 to 10 μm, and each component is mixed in the following proportions: the sintering aid is silica (5 to 10 wt%), the grinding aid is sodium hexametaphosphate (0.5 to 1.5 wt%), the dispersant is PEG (1 to 2 wt%), and the binder is a 2 to 5% PVA solution (0.2 to 0.8 wt%).

[0051] The intermediate layer pore diameter of the ceramic film produced in this step is 0.2 to 2 μm, the roughness Ra is 2.5 to 10 μm, and the Mohs hardness HM is 3 to 4.

[0052] Step (3) Create a separation layer. After uniformly stirring nanometer aluminum oxide powder, a sintering aid, a binder, and zirconia sol in a constant proportion, a separation layer paste is formed. Further coating, drying, and firing are then performed to form a separation layer of the film. Here, the median diameter D(50) of the aluminum oxide powder is 0.1 to 1 μm, and each component is mixed in the following proportions: the sintering aid is titanium oxide (10 to 15 wt%), and the binders are a 5 to 10% PVA solution (2 to 5 wt%) and zirconia sol (2 to 10 wt%).

[0053] The ceramic film fabricated in this step has a separation layer pore diameter of 50-80 nm, a roughness Ra of 0.2-0.4 μm, and a Mohs hardness HM of 8-9.

[0054] The ceramic membrane produced by the above method is the filter element of the dynamic ceramic membrane filtration system in Examples 1 to 3.

[0055] The ceramic film produced by the manufacturing method described in the present invention contains titanium dioxide in the separation layer, which causes water molecules adsorbed in water to dissociate, making it easier for hydroxyl groups to form on the surface compared to sintering aids used in other methods. This improves hydrophilicity, enhances the permeability of water molecules, and increases the filtration flux.

[0056] The added zirconia sol can significantly increase the hardness and bonding strength of the film layer, reaching a Mohs hardness of 8-9. The main principle is that during the high-temperature firing process, the tetragonal polycrystalline zirconia induces phase transition toughening and microcrack toughening. When treating high-hardness wastewater such as semiconductor silicon powder, silicon carbide, and diamond, the high-hardness, high-wear-resistant coating can have a longer-lasting effect.

[0057] The added zirconia sol strengthens the film while simultaneously reducing surface defects, making the film surface smoother. The roughness reaches Ra 0.2-0.4 μm, and it is difficult for fine nanoparticles to adhere to the surface during operation, leading to a decrease in film flux. Furthermore, the flux recovers significantly after backwashing.

[0058] The ceramic membranes manufactured using this method have a bending strength of 65-180 MPa, indicating high strength. Dynamic ceramic membranes require higher strength than static filtration ceramic membranes because they need to rotate at a specific speed during operation and use centrifugal force to remove contaminants from the membrane surface.

[0059] As shown in Figures 3-5, the ceramic membrane support layer and separation layer prepared in this invention are denser, have uniform pore sizes concentrated between 52 and 57 nm, and exhibit higher filtration accuracy.

[0060] Therefore, this ceramic membrane possesses high precision, high surface hardness, and low surface roughness, and the membrane layer (i.e., separation layer) has a longer lifespan and superior contamination prevention performance. When applied to high-hardness, ultra-wear-resistant, and ultra-fine semiconductor wastewater processes, it provides higher separation accuracy, stronger mechanical performance, greater stability, and a larger flux. By selecting a processing technology that combines such a dynamic ceramic membrane filtration system with a convergent filter, the process system operation is stable, separation accuracy is high, flux is stable, semiconductor particles and pure water can be recovered intensively, the system's energy consumption is lower, and it conforms to the country's carbon neutrality.

[0061] The series of detailed descriptions above are merely specific descriptions of possible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Equivalent embodiments or modifications that do not depart from the technical spirit of the present invention should be included within the scope of protection of the present invention.

[0062] Furthermore, although this specification describes embodiments, each embodiment does not necessarily contain only one independent technical solution. This descriptive form of this specification is simply for clarity, and those skilled in the art should understand that the specification should be considered as a whole, and that the technical solutions of each embodiment can be appropriately combined to form other embodiments that will be understood by those skilled in the art.

Claims

1. Step (1) involves performing solid-liquid separation treatment on wastewater from wafer cutting, grinding, and polishing in the semiconductor manufacturing process through a dynamic ceramic membrane filtration system. The resulting clarified liquid, after passing detection, enters a clean water tank for further treatment. If it fails the detection test, the solid-liquid separation treatment is repeated, and the resulting concentrated liquid enters a concentrated liquid tank. Step (2) involves performing a secondary solid-liquid separation treatment on the concentrated liquid from step (1) through a convergent filter, where fine particles accumulate on the surface of the filter element of the convergent filter to form a cake layer, and the permeate is returned to a dynamic ceramic membrane filtration system for recirculation treatment. Step (3) involves, after multiple circulation processes, all of the concentrated liquid generated by the dynamic ceramic membrane filtration system is placed into a convergent filter for final solid-liquid separation, and the cake layer is subjected to on-site dewatering and drying until its moisture content is 30% or less, followed by an automated slag discharge operation to recover the fine particles. Step (1) involves purifying the water in the clean water tank through an ultrafiltration system and / or an RO (reverse osmosis) filtration system, collecting ultrapure water for use, and then, step (4) involves circulating the concentrated water generated by the RO (reverse osmosis) filtration system back into a dynamic ceramic membrane filtration system for further treatment, ultimately achieving solid-liquid separation. Here, the filter element of the dynamic ceramic membrane filtration system is a ceramic membrane, and the separation layer of the ceramic membrane has hydrophilicity due to the inclusion of titanium oxide and high bending hardness due to the inclusion of zirconia. A comprehensive resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in semiconductor manufacturing processes, characterized in that the surface of the filter element of the convergent filter is covered with a nanofiber film, improving the solid-liquid separation efficiency of the convergent filter and reducing the water content of the cake layer.

2. The clarified liquid produced from the dynamic ceramic membrane filtration system in step (1) is entered into a clean water tank for treatment if the measured turbidity is less than 0.3 NTU, as described in claim 1, which is a comprehensive resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in a semiconductor manufacturing process.

3. The semiconductor manufacturing process according to claim 2, characterized in that the components of the fine particles are one of Si, Ce, SiC, CdTe, GaAs, InP, CdS, GaAlAs, and GaAsP, and further characterized in that it is a comprehensive resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing.

4. The process for the integrated recovery and utilization of wastewater from wafer cutting, grinding, and polishing in a semiconductor manufacturing process, as described in claim 2, characterized in that the operating pressure of the dynamic ceramic membrane filtration system is 0.01 to 0.2 MPa, the ceramic membrane has a filtration accuracy of 5 to 200 nm, and a rotation speed of 50 to 500 Hz.

5. The integrated resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in a semiconductor manufacturing process according to claim 4, characterized in that the operating pressure of the convergent filter is 0.2 to 1 MPa and the filtration accuracy of the filter element of the convergent filter is 0.2 to 1 μm.

6. The process for the comprehensive recovery and utilization of wastewater from wafer cutting, grinding, and polishing in a semiconductor manufacturing process, as described in claim 1, is characterized in that the wastewater from step (1) is first subjected to ultrasonic pretreatment, and then filtered and separated through a dynamic ceramic membrane filtration system.

7. The ultrasonic treatment is characterized by having a frequency of 20 to 60 kHz and an intensity of 2.0 to 10.0 kW, as described in claim 6, and is a comprehensive resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in a semiconductor manufacturing process.

8. The semiconductor manufacturing process according to claim 6, characterized in that ultrasonic pretreatment is performed when the median diameter D(50) of the fine particles in the wastewater is less than 50 nm.

9. Step (1) involves performing solid-liquid separation treatment on wastewater from wafer cutting, grinding, and polishing in the semiconductor manufacturing process, passing it through a first convergent filter, depositing fine particles on the surface of the filter element of the first convergent filter to form a cake layer, and then processing the permeate in a dynamic ceramic membrane filtration system. Step (2) involves the following steps: After the clarified liquid processed in the dynamic ceramic membrane filtration system passes detection, it enters the clean water tank for further processing; if it does not pass, it enters the first convergent filter for reprocessing, and the resulting concentrated liquid is returned to the first convergent filter for further processing. Step (3) involves, after multiple circulation processes, all the concentrated liquid generated by the dynamic ceramic membrane filtration system is placed into the first convergent filter for final solid-liquid separation, the cake layer is dewatered and dried on-site until the moisture content of the cake layer is 30% or less, an automatic slag discharge operation is performed, and fine particles are recovered. Step (2) involves purifying the water in the clean water tank through an ultrafiltration system and / or an RO (reverse osmosis) filtration system, collecting ultrapure water for use, and then returning the concentrated water produced by the RO (reverse osmosis) filtration system to the first convergent filter for circulation treatment, ultimately achieving solid-liquid separation. Here, the filter element of the dynamic ceramic membrane filtration system is a ceramic membrane, and the separation layer of the ceramic membrane has hydrophilicity due to the inclusion of titanium oxide and high bending hardness due to the inclusion of zirconia. A comprehensive resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in semiconductor manufacturing processes, characterized in that the surface of the filter element of the first convergent filter is covered with a nanofiber film, improving the solid-liquid separation efficiency of the first convergent filter and reducing the water content of the cake layer.

10. A second convergent filter is connected to the concentrated liquid outlet of the first convergent filter, the processing capacity of the first convergent filter is higher than that of the second convergent filter, the concentrated liquid from the first convergent filter in step (3) enters the second convergent filter, and the cake layer is subjected to on-site dewatering and drying until the moisture content of the cake layer is 30% or less, an automatic slag discharge operation is performed, and fine particles are recovered, characterized in that this is a comprehensive resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in a semiconductor manufacturing process according to claim 9.

11. The integrated resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in a semiconductor manufacturing process according to claim 1, characterized in that the process described in claim 1 is adopted when the particle size of the fine particles in the wastewater is less than 1 μm.

12. The comprehensive resource recovery and utilization process for wastewater from wafer cutting, grinding, and polishing in a semiconductor manufacturing process according to claim 9, characterized in that the process described in claim 9 is adopted when the particle size of the fine particles in the wastewater is 1 μm or larger.

13. Step (1) involves mixing micron-sized aluminum oxide powder with a sintering aid, pore-forming agent, dispersant, and binder in a constant proportion, grinding it in a ball mill for 4-6 hours to form a paste, further forming a support layer embryo through spray granulation and dry pressing processes, drying to remove moisture, and then firing to produce the support layer. Micron aluminum oxide powder is mixed with sintering aids, grinding aids, dispersants, and binders in a constant proportion and ground in a ball mill for 6-8 hours to form an intermediate layer paste. After coating, drying, and firing, the intermediate layer of the film is formed. Here, the intermediate layer pore diameter of the ceramic film fabricated in this step is 0.2 to 2 μm, the roughness Ra is 2.5 to 10 μm, and the Mohs hardness HM is 3 to 4. Step (2) is for fabricating the intermediate layer. After uniformly stirring nanometer aluminum oxide powder, a sintering aid, a binder, and zirconia sol in a constant proportion, a separation layer paste is formed. Further coating, drying, and firing are then performed to form a separation layer of the film. Hereinafter, the ceramic film produced in the step has a separation layer pore diameter of 50 to 80 nm, a roughness Ra of 0.2 to 0.4 μm, and a Mohs hardness HM of 8 to 9, and the method for producing a ceramic film used for the comprehensive recovery and utilization of wastewater from wafer cutting, grinding, and polishing in a semiconductor manufacturing process is characterized by comprising the step (3) of producing a separation layer.

14. A method for manufacturing a ceramic film used for the comprehensive recovery and utilization of wastewater from wafer cutting, grinding, and polishing in a semiconductor manufacturing process, as described in 13, characterized in that the median diameter D(50) of the aluminum oxide powder in step (1) is 5 to 30 μm, the median diameter D(50) of the aluminum oxide powder in step (2) is 5 to 10 μm, and the median diameter (50) of the aluminum oxide powder in step (3) is 0.1 to 1 μm.

15. The method for producing a ceramic film used for the comprehensive recovery and utilization of wastewater from wafer cutting, grinding, and polishing in a semiconductor manufacturing process, as described in 14, characterized in that the sintering aid described in step (1) is titanium dioxide (0.5 to 1.25 wt%), silica (2 to 5 wt%), or magnesium oxide (0.5 to 2.5 wt%), the pore-forming agent is one or more of starch (3 to 8 wt%), or carbon powder (1 to 7% wt%), cellulose (1.5 to 5 wt%), the dispersant is one or two of sodium hexametaphosphate and PEG (2 to 4 wt%), and the binder is a 10 to 15% concentration polyvinyl alcohol solution (2 to 5 wt%).

16. A method for producing a ceramic film used for the comprehensive recovery and utilization of wastewater from wafer cutting, grinding, and polishing in a semiconductor manufacturing process, as described in step (2) above, characterized in that the sintering aid described in step (2) is silica (5 to 10 wt%), the grinding aid is sodium hexametaphosphate (0.5 to 1.5 wt%), the dispersant is PEG (1 to 2 wt%), and the binder is a PVA solution with a concentration of 2 to 5% (0.2 to 0.8 wt%).

17. The method for producing a ceramic film used for the comprehensive recovery and utilization of wastewater from wafer cutting, grinding, and polishing in a semiconductor manufacturing process, as described in step (3) above, characterized in that the sintering aid is titanium oxide (10-15 wt%), and the binder is a 5-10% concentration PVA solution (2-5 wt%) or zirconia sol (2-10 wt%).

18. The method for manufacturing a ceramic film used for the comprehensive recovery and utilization of wastewater from wafer cutting, grinding, and polishing in a semiconductor manufacturing process, as described in claim 17, characterized in that the ceramic film is a filter element of the dynamic ceramic film filtration system described in claim 11 or claim 12.

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