Recycling system for wafer manufacturing working fluid
Through multi-stage filtration and sterilization treatment, the problem of removing silicon powder, oil and fungi in wafer processing fluid is solved, the efficient reuse of processing fluid and production stability are achieved, and equipment failure and cost increase are avoided.
Patent Information
- Application Number
- CN202422774923.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-14
- Publication Date
- 2025-10-17
- Estimated Expiration
- 2034-11-14
AI Technical Summary
Existing wafer processing fluid treatment systems are unable to effectively remove fine silicon powder, trace oil and fungi, resulting in reduced processing accuracy and production interruptions. Traditional liquid supply methods are prone to liquid deterioration and increased costs.
A multi-stage filtration system is used, including a primary treatment tank, a secondary treatment tank, and a liquid supply tank. Combined with candle filters, hydrodynamic cavitation systems, floating oil collection and separation devices, membrane filtration systems, and ultraviolet sterilization devices, multi-stage treatment and sterilization are carried out to ensure the cleanliness and stability of the processing fluid.
The company has achieved silicon powder particle size above 1μm with content below 30mg/L, tramp oil content less than 50mg/L, and fungus count less than 103 CFU/mL, ensuring high reuse rate of processing fluid and production continuity, and reducing the risk of equipment failure.
Smart Images
Figure CN223441803U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the field of semiconductor wafer processing waste liquid treatment, especially to the field of recycling of wafer cutting, grinding and polishing processing liquid in semiconductor process. BACKGROUND
[0002] In the manufacture of wafers, there are multiple process steps such as cutting, chamfering, and grinding. A large amount of processing liquid, including cutting fluid, chamfering liquid, and grinding liquid, is required for uninterrupted use during these processing steps. These processing liquids have good cooling and lubricating effects, reducing surface damage and mechanical stress of the semiconductor wafer, and reducing the problem of brittle cracking or scratches of the silicon wafer during cutting. This is conducive to the subsequent cleaning of the semiconductor wafer, effectively improves the thickness error of the semiconductor wafer, and improves the cutting yield. At the same time, these processing liquids have good corrosion and rust prevention properties for wafer manufacturing equipment, which can reduce equipment wear and maintenance frequency and increase production efficiency. Therefore, processing liquid plays a crucial role in wafer manufacturing.
[0003] During these cutting and grinding production processes, a large amount of fine silicon powder particles are generated. These silicon powders have a particle size distribution of 0.2-50 μm due to different processing methods. Since the flatness of the wafer before polishing is <500 nm, if the silicon powder in the processing liquid is not treated before reuse, it will cause a decrease in processing precision and even lead to the rejection of the wafer product. Therefore, the processing liquid needs to be filtered before reuse to remove impurities introduced during the manufacturing process and maintain a clean and stable level of the processing liquid.
[0004] Currently, the cutting fluid and grinding fluid in traditional mechanical manufacturing are generally reused by mechanical filtration after sedimentation. These methods can well match the precision requirements of mechanical equipment. Unlike traditional cutting fluid in mechanical manufacturing, the solid content level and solid particle size of wafer processing liquid have higher requirements. In traditional mechanical manufacturing, particles with a size of 8 μm or more can be reused at a content of less than 1000 mg / L. However, in wafer manufacturing, the cutting fluid, chamfering liquid, and grinding liquid need to have smaller particle sizes and lower contents to match the processing precision. Generally, the current wafer liquid reuse standard is that particles with a size of 1 μm or more should have a content of less than 30 mg / L.
[0005] In addition, in actual production, impurities in the used processing liquid include not only silicon powder brought by cutting and grinding, but also trace lubricants for cooling, which are mixed into the processing liquid of the wafer. The trace oil substances only increase the oil impurities in the entire processing liquid by dozens of micrograms under single mixing, and do not reduce the processing precision and quality of the product. However, if the processing liquid is recycled, the trace oil is not treated, and the oil is accumulated in the system, which quickly affects the efficiency of the cleaning link, and causes uneven cutting and grinding and defects of the wafer at a higher concentration. Therefore, the treatment of the trace oil needs to be considered in the treatment before reuse. The oil is low in content, and the general treatment methods such as air floatation, coalescence and absorption have low efficiency, and the oil is not easy to remove. Therefore, an effective treatment method needs to be used. The problem of bacterial growth in the used processing liquid also needs to be considered. Although the environment of wafer manufacturing is clean, the bacterial growth is slow, but the bacteria still rise to a certain extent after flowing through the complex pipeline of the manufacturing equipment for a long time. If the processing liquid is recycled, the bacteria in the liquid will gradually exceed the limit, and the organic components in the liquid are consumed, which causes the deterioration of the liquid. Therefore, the recycling treatment equipment also needs to consider the treatment of the bacteria to ensure the stability of the liquid.
[0006] At the same time, due to the flow load impact of the general circulating liquid supply system, the direct liquid supply method is easy to cause flow interruption, and therefore the indirect liquid supply method is generally used, and a buffer tank is arranged. However, the indirect liquid supply method first causes the storage liquid in the system to be significantly higher than the liquid amount required in actual production, which leads to the increase of the production cost, and the storage liquid in the buffer tank is retained in the tank in a large amount in the production trough and cannot be effectively maintained and treated, which is easy to deteriorate and cause the production interruption.
[0007] In summary, it is necessary to find a comprehensive treatment process and system to continuously recycle and maintain the wafer processing liquid, ensure that the particulate matter, oil and bacteria are below the limit and stable, and continuously supply the production section with direct liquid to ensure the stability of the liquid supply. SUMMARY
[0008] In order to solve the above problems of the existing wafer processing liquid treatment, the wafer manufacturing processing liquid recycling system provided by the utility model can concentrate the wafer processing liquid, remove the impurities in the processing liquid through multi-stage treatment of the solid particles, sterilize the recycled liquid, and ensure the effective components and proportion of the wafer processing liquid without adding chemical agents and bactericides, so that the recycling rate is high.
[0009] Based on the above problems, the present scheme is as follows:
[0010] The application discloses a wafer manufacturing processing liquid recycling system, which comprises a first treatment tank, a second treatment tank and a liquid supply tank, the first treatment tank is communicated with the second treatment tank, a candle filter is connected between the first treatment tank and the liquid supply tank, and a bag filter is connected between the second treatment tank and the liquid supply tank.
[0011] The second treatment tank is connected with a water power cavitation system, and a floating oil collecting and separating device is connected above the second treatment tank.
[0012] Preferably, the liquid supply tank is connected with a membrane circulation liquid tank, the membrane circulation liquid tank is connected with a membrane filtration system, and the membrane filtration system is connected with the liquid supply tank.
[0013] Preferably, the first treatment tank is provided with a conical bottom at the bottom, the conical bottom is connected with the candle filter, a pump and a valve are connected between the first treatment tank and the candle filter, and the candle filter is connected with the liquid supply tank.
[0014] Preferably, the second treatment tank is provided with a conical bottom at the bottom, the conical bottom is connected with a first centrifugal machine, and the first centrifugal machine is connected with the second treatment tank.
[0015] Preferably, a baffle forming a zigzag route is arranged between the first treatment tank and the second treatment tank, the distance between the side baffle of the first treatment tank and the bottom of the first treatment tank is greater than zero, and the upper side of the side baffle of the second treatment tank is lower than the side baffle of the first treatment tank.
[0016] Preferably, the membrane filtration system is a ceramic membrane filtration system, the ceramic membrane filtration system comprises an inlet, a concentrated liquid outlet and a clean liquid outlet, the inlet is connected with the membrane circulation liquid tank, the concentrated liquid outlet is connected with the membrane circulation liquid tank, and the clean liquid outlet is connected with the liquid supply tank.
[0017] Preferably, an ultraviolet sterilization device is connected between the clean liquid outlet and the liquid supply tank, and a flow meter is arranged between the clean liquid outlet and the ultraviolet sterilization device.
[0018] Preferably, the membrane circulation liquid tank is further connected with a solid-liquid separation device, the solid-liquid separation device is connected with the second treatment tank, and the solid-liquid separation device is a second centrifugal machine or a plate-and-frame filter press.
[0019] Preferably, the first treatment tank is connected with a machine tool end liquid supply and return module, and the liquid supply tank is connected with a constant pressure liquid supply module, the constant pressure liquid supply module is connected with the machine tool end liquid supply and return module.
[0020] The application also provides a wafer manufacturing processing liquid recycling system, which comprises a first treatment tank, a second treatment tank and a liquid supply tank, the first treatment tank and the second treatment tank are connected with a candle filter through valves respectively, and the candle filter is connected with the liquid supply tank.
[0021] The second treatment tank is connected with a hydrodynamic cavitation system, and a floating oil collecting and separating device is connected above the second treatment tank.
[0022] The application also provides a wafer manufacturing processing liquid recycling system, which comprises a first treatment tank, a second treatment tank and a liquid supply tank, the first treatment tank and the second treatment tank are connected with a first centrifuge through valves respectively, and the liquid outlet of the first centrifuge is connected with the first treatment tank and the second treatment tank through valves respectively; and a bag filter is connected between the second treatment tank and the liquid supply tank.
[0023] The second treatment tank is connected with a hydrodynamic cavitation system, and a floating oil collecting and separating device is connected above the second treatment tank.
[0024] The liquid supply tank is connected with a membrane circulation liquid tank, and the membrane circulation liquid tank is connected with a membrane filtration system.
[0025] Compared with the prior art, the application has the following beneficial technical effects:
[0026] 1. The silicon powder in the processing liquid is treated in multiple stages with high precision and high efficiency, and the content of the silicon powder with a particle size higher than 1 μm in the treated liquid is less than 30 mg / L.
[0027] 2. The liquid containing impurities and fine particles in the upper layer of the first treatment tank enters the second treatment tank, the liquid in the second treatment tank is subjected to hydrodynamic cavitation treatment, and the micro-impurities are treated thoroughly, so that the content of the impurities in the liquid supply section is less than 50 mg / L.
[0028] 3. An ultraviolet sterilization device is arranged between the clean liquid outlet of the membrane filtration system and the liquid supply tank, the bacteria in the liquid are treated by physical means, no bactericide or oxidant is added, the composition of the liquid is not changed, and the number of bacteria is less than 103 CFU / mL.
[0029] 4. The main treatment process equipment is a bypass equipment, and the failure of the equipment will not cause interruption of production; a special liquid supply mode is adopted to ensure uninterrupted direct liquid supply; the separated silicon powder and other solid impurities have a very low water content, and generally no waste liquid is discharged. BRIEF DESCRIPTION OF DRAWINGS
[0030] Figure 1 It is a system flow chart of the wafer manufacturing processing liquid recycling system of Example 2.
[0031] Figure 2The structure flow chart of the recycling system of the wafer manufacturing processing liquid of Example 1.
[0032] Figure 3 The structure flow chart of the recycling system of the wafer manufacturing processing liquid of Example 2.
[0033] Figure 4 The structure flow chart of the recycling system of the wafer manufacturing processing liquid of Example 3.
[0034] Figure 5 The structure flow chart of the membrane filtration of the wafer manufacturing processing liquid in another mode.
[0035] In the figure: the first-stage treatment tank 1, the first-stage treatment tank side partition 100, the valve 101, the second-stage treatment tank 2, the second-stage treatment tank side partition 200, the valve 201, the liquid supply tank 3, the membrane circulation liquid tank 4, the candle filter 5, the hydrodynamic cavitation generator 6, the high-pressure pump 60, the floating oil collection and separation device 7, the bag filter 8, the ceramic membrane filtration system 9, the liquid inlet 90, the concentrated liquid outlet 91, the clean liquid outlet 92, the ultraviolet sterilization device 10, the plate-and-frame filter press 11, the first centrifuge 12, the second centrifuge 13, and the constant-pressure liquid supply module 14. DETAILED DESCRIPTION
[0036] The utility model will be described further in combination with the drawings and the specific embodiments:
[0037] The particle size range of the particles in the wafer processing liquid is relatively large, ranging from 0.2 to 50 μm. In this application, the particle size below 8 μm is defined as fine particles, and the particle size above 8 μm is defined as large particles. According to the proportion of large particles in the total particles, there are three cases: the proportion of large particles is below 20%, 20% to 50%, and above 50%. According to the proportion of large particles in different ranges, different treatment schemes are adopted.
[0038] Example 1:
[0039] For the proportion of large particles above 50%, the scheme of Example 1 is adopted.
[0040] As shown in Figure 2 The recycling system of the wafer manufacturing processing liquid includes the first-stage treatment tank 1 and the second-stage treatment tank 2. The first-stage treatment tank 1 is in communication with the second-stage treatment tank 2. The first-stage treatment tank 1 and the second-stage treatment tank 2 are connected to the candle filter 5 through the valve 101 and the valve 201, respectively. The candle filter 5 is connected to the liquid supply tank 3. The first-stage treatment tank 1 and the second-stage treatment tank 2 are each provided with a conical bottom, which is connected to the candle filter 5. A pump is arranged between the first-stage treatment tank 1, the second-stage treatment tank 2, and the candle filter 5.
[0041] A partition forming a deflection route is provided between the primary treatment tank 1 and the secondary treatment tank 2. The distance between the primary treatment tank side partition 100 and the bottom of the primary treatment tank 1 is greater than zero, the upper part of the secondary treatment tank side partition 200 is lower than the primary treatment tank side partition 100, and the slot of the primary treatment tank is also provided with a buffer bevel; the liquid entering the secondary treatment tank 2 is the upper layer liquid, and the lower layer turbid liquid with a higher content of particulate matter remains in the primary treatment tank 1; the liquid in the secondary treatment tank 2 has a lower solid content than that in the primary treatment tank 1, and the particle size of the particulate matter is smaller.
[0042] The secondary treatment tank 2 is also connected to a hydrodynamic cavitation system, which includes a high-pressure pump 60 and a hydrodynamic cavitation generator 6, which are connected in sequence. The liquid inlet of the high-pressure pump 60 is connected to the secondary treatment tank 2, and the liquid outlet of the hydrodynamic cavitation generator 6 is connected to the secondary treatment tank 2. A floating oil collection and separation device 7 is also connected to the liquid surface of the secondary treatment tank 2. The liquid inlet of the floating oil collection and separation device is set above the liquid surface of the secondary treatment tank 2, and the liquid outlet of the floating oil collection and separation device extends below the liquid surface of the secondary treatment tank 2. The liquid inlet of the floating oil collection and separation device can also be set above the liquid surface of the primary treatment tank 1.
[0043] The liquid supply tank 3 is connected to the liquid supply and return module at the machine tool end through the constant pressure liquid supply module 14.
[0044] The working method of the wafer manufacturing process fluid recycling system of Example 1 is as follows:
[0045] The return fluid module at the machine tool introduces the post-wafer processing fluid into the primary treatment tank 1. Sedimentation occurs in the primary treatment tank 1, causing large particles to settle at the conical bottom. Smaller particles are diverted by partitions into the secondary treatment tank 2. The primary and secondary treatment tanks 1 and 2 are then alternately treated by candle filters 5. The resulting clean liquid is then introduced into the supply tank 3. The candle filters 5 consist of a filter tank and several filter elements within the tank. Filter bags are installed on the filter elements. Large particles form a filter cake on the surface of the filter bags. When the filter cake reaches a certain thickness, it traps fine silicon powder particles in the wastewater, and the candle filters begin to discharge clear liquid. The clean liquid produced by candle filtration has a low particle content and high cleanliness.
[0046] A hydrodynamic cavitation generator 6 is connected to the secondary treatment tank 2 to perform hydrodynamic cavitation treatment on the liquid within the secondary treatment tank, breaking up any emulsified miscellaneous oil in the processing fluid. Floating oil, accompanied by fine particles, rises to the surface and is collected by a floating oil collection and separation device 7 for further oil-liquid separation. The waste oil is collected in a waste oil drum (not shown) and then introduced back into the secondary treatment tank 2. After cavitation de-oiling, particulate matter is removed by a candle filter, resulting in a liquid with low oil and solids content entering the liquid supply tank 3.
[0047] Example 2:
[0048] For the large particle ratio in 20%~50%, the scheme of example 2 is adopted.
[0049] As shown in Figure 1 , the wafer manufacturing processing liquid recycling system comprises a machine tool end liquid supply and return module, a first treatment tank, a second treatment tank, a liquid supply tank, the machine tool end liquid supply and return module is connected with the first treatment tank, a candle filter is connected between the first treatment tank and the liquid supply tank, the liquid supply tank is connected with a membrane circulation liquid tank; the membrane circulation liquid tank is connected with a membrane filtration system, and the membrane filtration system is connected with the liquid supply tank. The second treatment tank is connected with a hydrodynamic cavitation system, and a floating oil collection and separation device is connected above the second treatment tank. The second treatment tank is also connected with a first centrifuge, a bag filter is connected above the second treatment tank, and the bag filter is connected with the liquid supply tank. The membrane circulation liquid tank is also connected with a solid-liquid separation device. The liquid supply tank is connected with the machine tool end liquid supply and return module through a constant pressure liquid supply module. The candle filter, the first centrifuge and the solid-liquid separation device are all provided with slag collection. The control system controls the candle filter, the first centrifuge, the membrane filtration system, the hydrodynamic cavitation system and the floating oil collection and separation device.
[0050] As shown in Figure 3 , the wafer manufacturing processing liquid recycling system comprises a first treatment tank 1 and a second treatment tank 2, and the first treatment tank 1 is communicated with the second treatment tank 2; a candle filter 5 is connected between the first treatment tank 1 and a liquid supply tank 3, the first treatment tank 1 is provided with a conical bottom, the conical bottom is connected with the candle filter 5, and the candle filter 5 is connected with the liquid supply tank 3; a valve and a pump are arranged between the conical bottom and the candle filter 5.
[0051] As shown in Figure 3 , the large particle ratio of the wafer processing liquid is in the range of 20%~50%, the first treatment tank 1 is connected with the candle filter 5, the candle filter comprises a filter tank and a plurality of filter cores arranged in the filter tank, a filter bag is arranged on the filter core, a filter cake is formed on the surface of the filter bag with a large particle size, the filter cake reaches a certain thickness, the fine particle size silicon powder particles in the waste liquid are intercepted, and the candle filter starts to discharge clean liquid. The particle content of the clean liquid discharged from the candle filter is low, and the cleanliness of the liquid is high.
[0052] As shown in Figure 3 , a partition plate forming a zigzag route is arranged between the first treatment tank 1 and the second treatment tank 2, the distance between the first treatment tank side partition plate 100 and the bottom of the first treatment tank 1 is greater than zero, and the upper portion of the second treatment tank partition plate 200 is lower than the first treatment tank side partition plate 100, so that the liquid entering the second treatment tank 2 is upper clear liquid, and the lower turbid liquid with a large particle content remains in the first treatment tank 1; the liquid in the second treatment tank 2 has a smaller solid content and smaller particle size than the first treatment tank 1.
[0053] As shown in Figure 3, the secondary treatment tank 2 is also connected to a hydrodynamic cavitation system, the hydrodynamic cavitation system comprising a high-pressure pump 60 and a hydrodynamic cavitation generator 6 connected in sequence, the liquid inlet of the high-pressure pump 60 being connected to the secondary treatment tank 2, and the liquid outlet of the hydrodynamic cavitation generator 6 being connected to the secondary treatment tank 2. The secondary treatment tank 2 is also connected to a floating oil collection and separation device 7 at the liquid surface.
[0054] As shown in Figure 3 , the secondary treatment tank 2 is provided with a conical bottom connected to a first centrifuge 12, and the liquid outlet of the first centrifuge 12 is connected to the secondary treatment tank 2. A valve and a pump are provided between the secondary treatment tank 2 and the first centrifuge 12. The secondary treatment tank 2 is connected to a liquid supply tank 3 through a bag filter 8, and a valve and a pump are provided between the secondary treatment tank 2 and the bag filter 8. The clean liquid of the bag filter 8 is introduced into the liquid supply tank 3.
[0055] The secondary treatment tank 2 is subjected to a cycle centrifugal treatment by the first centrifuge 12, so that the particles in the secondary treatment tank are further separated, and then subjected to a precision filtration by the bag filter, and the clean liquid filtered by the bag filter is sent to the liquid supply tank 3. The liquid in the liquid supply tank 3 is relatively clean, but the proportion of large particles of the wafer processing liquid is in the range of 20% to 50%, the proportion of fine particles is large, and there are some ultra-fine silicon powder particles, which cannot guarantee to meet the reuse standard.
[0056] As shown in Figure 3 , the liquid supply tank 3 is connected to a membrane circulation liquid tank 4, and a valve and a pump are provided between the liquid supply tank 3 and the membrane circulation tank 4. The membrane circulation liquid tank 4 is connected to a membrane filtration system. The membrane filtration system is a ceramic membrane filtration system 9. The ceramic membrane filtration system 9 comprises a liquid inlet 90, a concentrated liquid outlet 91, and a clean liquid outlet 92. The liquid inlet 90 is connected to the membrane circulation liquid tank 4, and a pump and a valve are provided between the liquid inlet 90 and the membrane circulation liquid tank 4. The concentrated liquid outlet 91 is connected to the membrane circulation liquid tank 4, and the clean liquid outlet 92 is connected to the liquid supply tank 3.
[0057] The membrane circulation liquid tank 4 and the ceramic membrane filtration system 9 serve as a bypass of the liquid supply tank 3, and further filter the small amount of ultra-fine silicon powder particles in the liquid supply tank, without affecting the liquid supply to the machine tool end by the liquid supply tank 3. The ceramic membrane filtration system 9 is one of a tubular ceramic membrane and a flat plate ceramic membrane. The ceramic membrane tube material is silicon carbide, which has a large flux and is not easy to block, and the number of backwashing is small, and the treatment efficiency is high.
[0058] As shown in Figure 5 , the clean liquid outlet 92 is connected to an ultraviolet sterilization device 10, which sterilizes the reused liquid entering the liquid supply tank 3, so as to ensure that the bacterial content of the reused liquid is the lowest.
[0059] As shown in Figure 3 , Figure 5As shown, the membrane circulating liquid tank 4 is also connected to a solid-liquid separation device, and the solid-liquid separation device is connected to the secondary treatment tank 2. The solid-liquid separation device is a second centrifuge 13 or a plate-and-frame filter press 11, which further separates the concentrated liquid in the membrane circulating liquid tank. The liquid separated by centrifugation or the filtrate filtered by the plate-and-frame filter press is introduced into the secondary treatment tank 2, and the ultra-fine silicon powder is dewatered by the second centrifuge 13 or the plate-and-frame filter press 11, thereby obtaining the recyclable high-purity ultra-fine silicon powder.
[0060] In this embodiment, the first centrifuge 12 and the second centrifuge 13 are high-speed centrifuges.
[0061] The working mode of the wafer manufacturing process liquid recycling system of Example 2 is as follows:
[0062] The machine tool end liquid supply module introduces the processed liquid after wafer processing into the primary treatment tank 1. In the primary treatment tank 1, large-particle-size particulates are precipitated at the conical bottom of the primary treatment tank 1, and the waste liquid with a large proportion of large-particle-size particulates is pumped to the candle filter 5 to form a filter cake on the surface of the filter bag. When the filter cake reaches a certain thickness, the small-particle-size silicon powder particulates in the waste liquid are intercepted, the candle filter starts to discharge the clear liquid, and the clear liquid is introduced into the liquid supply tank 3. The waste liquid with a large proportion of fine particulates in the secondary treatment tank 2 is introduced into the first centrifuge 12 for high-speed centrifugal treatment. The clean liquid in the upper layer of the secondary treatment tank 2 is precisely filtered by the bag filter 8. The bag filter is an up-flow filter bag or a down-flow filter bag. When the amount of particulates in the up-flow filter bag reaches a certain amount, the filter bag needs to be taken out from the filter tank and poured out. The particulates are adsorbed on the outside of the down-flow filter bag, and the automatic deslagging can be performed by back flushing. The clear liquid filtered by the bag filter 8 is also introduced into the liquid supply tank 3. The treatment liquid in the liquid supply tank 3 has a relatively low solid content and a small particle size.
[0063] The hydraulic cavitation generator 6 is connected to the secondary treatment tank 2 to perform hydraulic cavitation treatment on the liquid in the secondary treatment tank 2, so that the emulsified oil in the processing liquid is broken out, and the floating oil with fine particulates is floated to the liquid surface and collected by the floating oil collecting and separating device 7. The waste oil is collected by the waste oil tank (not shown in the figure), and the liquid is introduced into the secondary treatment tank 2 again. After the cavitation oil removal, the particulates are removed by the candle filter and the bag filter, so that the liquid entering the liquid supply tank 3 has a low oil content and a low solid content.
[0064] In order to meet the recycling standards, the liquid supply tank 3 is also connected to the membrane circulating liquid tank 4, a part of the liquid is discharged into the membrane circulating liquid tank 4, and the membrane circulating liquid tank 4 is treated by the membrane filtration system 9. The clean liquid is discharged into the liquid supply tank 3. The liquid in the membrane circulating liquid tank is gradually concentrated, the concentrated liquid is introduced into the solid-liquid separation device, and the solid-liquid separation device can be a second centrifuge or a plate-and-frame filter press. The concentrated liquid is further centrifuged and dewatered by the plate-and-frame filter press, and the ultra-fine silicon powder is collected; the filtrate is introduced into the secondary treatment tank 2.
[0065] Example 3.
[0066] For the large particle ratio of 20% or less, the scheme of Example 3 is adopted.
[0067] As shown in Figure 4 , the wafer manufacturing process liquid recycling system comprises a first treatment tank 1 and a second treatment tank 2, the first treatment tank 1 is communicated with the second treatment tank 2, the first treatment tank 1 and the second treatment tank 2 are both provided with a conical bottom, the conical bottom is connected with a first centrifuge 12 through a valve respectively, and the liquid outlet of the first centrifuge 12 is connected with the first treatment tank 1 and the second treatment tank 2 through a valve respectively. The second treatment tank 2 is connected with a liquid supply tank 3 through a bag filter 8, and the clean liquid of the bag filter 3 is introduced into the liquid supply tank 3.
[0068] As shown in Figure 4 , the second treatment tank 2 is also connected with a hydrodynamic cavitation system, the hydrodynamic cavitation system comprises a high-pressure pump 60 and a hydrodynamic cavitation generator 6 connected in sequence, the liquid inlet of the high-pressure pump 60 is connected with the second treatment tank 2, and the liquid outlet of the hydrodynamic cavitation generator 6 is connected with the second treatment tank 2. A floating oil collecting and separating device 7 is also connected on the liquid surface of the second treatment tank 2.
[0069] As shown in Figure 4 , the liquid supply tank 3 is connected with a membrane circulating liquid tank 4, and a pump and a valve are connected between the liquid supply tank 3 and the membrane circulating tank 4. The membrane circulating liquid tank 4 is connected with a ceramic membrane filtration system 9. The ceramic membrane filtration system 9 comprises a liquid inlet 90, a concentrated liquid outlet 91 and a clean liquid outlet 92, the liquid inlet 90 is connected with the membrane circulating liquid tank 4, the concentrated liquid outlet 91 is connected with the membrane circulating liquid tank 4, and the clean liquid outlet 92 is connected with the liquid supply tank 3. The ceramic membrane filtration system 9 is used as a bypass of the liquid supply tank to further filter the ultra-fine silicon powder particles with low content in the liquid supply tank. Figure 5 As shown in , the clean liquid outlet 92 is connected with the liquid supply tank 3 through an ultraviolet sterilization device 10 to sterilize the liquid with high cleanliness entering the liquid supply tank 3.
[0070] Figure 4 As shown in Figure 5 , the membrane circulating liquid tank 4 is also connected with a solid-liquid separation device, and the solid-liquid separation device is connected with the second treatment tank 2. The solid-liquid separation device is a second centrifuge 13 or a plate-and-frame filter press 11 to further separate the concentrated liquid in the membrane circulating liquid tank. The liquid separated by centrifugation or the filtrate filtered by the plate-and-frame filter press is introduced into the second treatment tank 2, and the ultra-fine silicon powder is dewatered by the second centrifuge 13 or the plate-and-frame filter press 11 to obtain the recyclable high-purity ultra-fine silicon powder.
[0071] In this embodiment, the first centrifuge 12 and the second centrifuge 13 are high-speed centrifuges.
[0072] Working mode of the wafer manufacturing process liquid recycling system of Example 3:
[0073] The machine tool end liquid supply and return module introduces the wafer processed process liquid into the primary treatment tank 1. In the primary treatment tank 1, large particle matters are precipitated at the conical bottom of the primary treatment tank 1, and part of small particles are deflected into the secondary treatment tank 2 through the baffle. The primary treatment tank and the secondary treatment tank 2 are alternately and circularly treated by the first centrifuge 12, part of large particles are separated by centrifugation, and the liquid of the secondary treatment tank is further precisely filtered by the bag filter 8. The filtrate is introduced into the liquid supply tank 3.
[0074] The hydraulic cavitation generator 6 is connected in the secondary treatment tank 2 to perform hydraulic cavitation treatment on the liquid in the secondary treatment tank 2, so that the emulsified oil in the process liquid is broken out, and the floating oil with fine particles is floated to the liquid surface and collected by the floating oil collecting device 7 and further oil separation. The waste oil is collected by the waste oil tank, and the liquid is introduced into the secondary treatment tank 2. After cavitation oil removal, the particles are removed by the bag filter, so that the oil content and solid content of the liquid entering the liquid supply tank 3 are low.
[0075] In order to meet the recycling standard, the liquid supply tank 3 is also connected to the membrane circulating liquid tank 4, part of the liquid is discharged into the membrane circulating liquid tank 4, and the membrane circulating liquid tank 4 is circularly concentrated by the ceramic membrane filtration system 9. The clean liquid is discharged into the liquid supply tank 3. The liquid in the membrane circulating liquid tank is gradually concentrated, and the concentrated liquid is introduced into the solid-liquid separation device, which can be a second centrifuge or a plate and frame filter press. The concentrated liquid is further spun dry or dried by plate and frame extrusion, and the slag of ultra-fine silicon powder is collected; the filtrate is introduced into the secondary treatment tank 2.
[0076] The application is further described below in combination with test cases and test data.
[0077] 1. Test case of Example 1:
[0078] The silicon wafer chamfering liquid of a certain factory is circularly filtered and treated, and the particle concentration and particle size of the chamfering liquid after chamfering process are tested. The total content of solid particles in the used chamfering liquid is 2.00 g / L, the particle size of 8 μm or more is 1.81 g / L, the large particles account for 90%, and the impurity oil content is 150 mg / L. The liquid is treated by the process flow of Example 1.
[0079] (1) The used chamfering liquid is introduced into the first treatment tank 1, the lower liquid is directly introduced into the candle filter 5, the filtrate treated by the candle filter is introduced into the liquid supply tank, and the upper liquid is introduced into the secondary treatment tank 2 through the overflow port.
[0080] (2) The middle and upper layer liquid in the secondary treatment tank 2 enters the hydrodynamic cavitation system for oil removal treatment, the floating oil on the liquid surface is collected by the oil collection and separation device 7, and the lower layer liquid enters the candle filter, and the filtrate treated by the candle filter 5 enters the liquid supply tank 3.
[0081] (3) The filtrate treated by the candle filter 5 enters the liquid supply tank 3.
[0082] After treatment, the total content of solid particles in the liquid is 0.016 g / L, and the content of impurities is 23 mg / L, reaching the reuse standard.
[0083] 2, the test case of example 2 is adopted:
[0084] The wire cutting liquid of a certain factory is treated by circulating filtration, the particle concentration and particle size of the wire cutting liquid after cutting process are tested, the used wire cutting liquid is obtained, the total content of solid particles is 3.21 g / L, the particle size of more than 8 μm is 1.33 g / L, the proportion of large particles is 40%, and the content of impurities is 210 mg / L. The process flow of example 2 is adopted to treat the liquid.
[0085] (1) The used chamfering liquid is introduced into the primary treatment tank 1, the lower layer liquid directly enters the candle filter, the filtrate treated by the candle filter enters the liquid supply tank 3, and the middle and upper layer liquid enters the secondary treatment tank 2 through the overflow port.
[0086] (2) The middle and upper layer liquid in the secondary treatment tank 1 enters the hydrodynamic cavitation system for oil removal treatment, the floating oil on the liquid surface is collected by the oil collection and separation device 7, and the lower layer liquid enters the high-speed centrifuge in the bypass of the secondary treatment tank 2 for filtration, the filtrate returns to the middle layer of the secondary treatment tank 2, and the upper layer liquid treated by the oil removal centrifuge enters the liquid supply tank 3 through the bag filter 8.
[0087] (3) Part of the liquid in the liquid supply tank 3 enters the membrane circulation liquid tank 4, and the membrane system in the bypass of the membrane circulation tank is opened for circulation, so that the particle concentration does not exceed the standard.
[0088] (4) The concentrated liquid of the membrane circulation liquid tank is filtered by the high-speed centrifuge and returned to the secondary treatment tank 2.
[0089] After treatment, the total content of solid particles in the liquid is 0.025 g / L, and the content of impurities is 22 mg / L, reaching the reuse standard.
[0090] 3, the test case of example 3 is adopted:
[0091] The silicon wafer grinding liquid of a factory is treated by circulating filtration, and the particle concentration and particle size of the grinding liquid after grinding process are tested, so that the total content of solid particles in the used chamfering liquid is 1.20 g / L, the particle size of more than 8 μm is 0.23 g / L, the proportion of large particles is 20%, and the impurity oil is 120 mg / L. The liquid is treated by the process flow of Example 3.
[0092] (1) The used chamfering liquid is introduced into the first treatment tank 1, the lower liquid directly enters the high-speed centrifuge, the filtrate returns to the middle layer of the first treatment tank 1, and the upper liquid enters the second treatment tank 2 through the overflow port.
[0093] (2) The upper liquid in the second treatment tank 1 enters the cavitation system for oil removal treatment, the floating oil on the liquid surface is collected and separated by the oil collection and separation device 7, the lower liquid enters the high-speed centrifuge of the bypass of the second treatment tank 2 for filtration, the filtrate returns to the middle layer of the second treatment tank, and the upper liquid after oil removal centrifugation is filtered by the bag filter 8 and then enters the liquid supply tank 3.
[0094] (3) Part of the liquid in the liquid supply tank 3 enters the membrane circulating liquid tank 4, the bypass membrane system of the membrane circulating liquid tank is opened for circulation, so that the particle concentration does not exceed the standard.
[0095] (4) The concentrated liquid of the membrane circulating liquid tank is filtered by the high-speed centrifuge and returned to the second treatment tank 2.
[0096] The total content of solid particles in the treated liquid is 0.025 g / L, and the content of impurity oil is 20 mg / L, which meets the reuse standard.
[0097] The above is only a specific embodiment of the present application, but the technical features of the present application are not limited to this. Any simple change, equivalent replacement or modification made on the basis of the present application to solve the same technical problem and achieve the same technical effect is also covered by the protection scope of the present application.
Claims
1. A wafer manufacturing fluid recycling system, characterized in that: The recycling system includes a primary treatment tank, a secondary treatment tank, and a liquid supply tank. The primary treatment tank is connected to the secondary treatment tank. A candle filter is connected between the primary treatment tank and the liquid supply tank. A bag filter is connected between the secondary treatment tank and the liquid supply tank. The secondary treatment tank is connected to a hydrodynamic cavitation system, and the upper portion of the secondary treatment tank is connected to a floating oil collection and separation device; A partition forming a baffle path is provided between the primary treatment tank and the secondary treatment tank; The distance between the side partition of the primary treatment tank and the bottom of the primary treatment tank is greater than zero, and the upper part of the side partition of the secondary treatment tank is lower than the side partition of the primary treatment tank.
2. The wafer manufacturing process fluid recycling system according to claim 1, characterized in that: The liquid supply tank is connected to the membrane circulation liquid tank; the membrane circulation liquid tank is connected to the membrane filtration system; and the membrane filtration system is connected to the liquid supply tank.
3. The wafer manufacturing process fluid recycling system according to claim 1, characterized in that: The bottom of the primary treatment tank is provided with a conical bottom, and the conical bottom is connected to the candle filter; a pump and a valve are connected between the primary treatment tank and the candle filter; and the candle filter is connected to a liquid supply tank.
4. The wafer manufacturing process fluid recycling system according to claim 1, characterized in that: The bottom of the secondary treatment tank is provided with a conical bottom, the conical bottom is connected to the first centrifuge, and the first centrifuge is connected to the secondary treatment tank.
5. The wafer manufacturing process fluid recycling system according to claim 2, characterized in that: The membrane filtration system is a ceramic membrane filtration system, which includes a liquid inlet, a concentrated liquid outlet, and a clean liquid outlet. The liquid inlet is connected to the membrane circulation liquid tank, the concentrated liquid outlet is connected to the membrane circulation liquid tank, and the clean liquid outlet is connected to the liquid supply tank.
6. The wafer manufacturing process fluid recycling system according to claim 5, characterized in that: An ultraviolet sterilization device is connected between the clean liquid outlet and the liquid supply tank; and a flow meter is provided between the clean liquid outlet and the ultraviolet sterilization device.
7. The wafer manufacturing process fluid recycling system according to claim 2, characterized in that: The membrane circulation liquid tank is also connected to a solid-liquid separation device, and the solid-liquid separation device is connected to the secondary treatment tank; the solid-liquid separation device is a second centrifuge or a plate and frame filter press.
8. The wafer manufacturing process fluid recycling system according to claim 1, characterized in that: The primary treatment tank is connected to the machine tool end liquid supply and return module; the liquid supply tank is connected to the constant pressure liquid supply module, and the constant pressure liquid supply module is connected to the machine tool end liquid supply and return module.
9. A wafer manufacturing process fluid recycling system, characterized in that: The recycling system includes a primary treatment tank, a secondary treatment tank, and a liquid supply tank. The primary treatment tank and the secondary treatment tank are respectively connected to a candle filter through a valve, and the candle filter is connected to the liquid supply tank. The secondary treatment tank is connected to a hydrodynamic cavitation system, and the upper part of the secondary treatment tank is connected to a floating oil collection and separation device.
10. A wafer manufacturing fluid recycling system, characterized in that: The recycling system includes a primary treatment tank, a secondary treatment tank, and a liquid supply tank. The primary treatment tank and the secondary treatment tank are respectively connected to a first centrifuge through valves. The liquid outlet of the first centrifuge is respectively connected to the primary treatment tank and the secondary treatment tank through valves. A bag filter is connected between the secondary treatment tank and the liquid supply tank. The secondary treatment tank is connected to a hydrodynamic cavitation system, and the upper portion of the secondary treatment tank is connected to a floating oil collection and separation device; The liquid supply tank is connected to the membrane circulation liquid tank; and the membrane circulation liquid tank is connected to the membrane filtration system.