Cutting fluid circulating filtration system for semiconductor processing

Abstract

The utility model discloses a cutting fluid circulating filtration system used in semiconductor processing, which comprises a precise filtration unit, the precise filtration unit comprises at least one filtration tank, a plurality of filter elements are arranged in the filtration tank, each filter element comprises a filter rod and a filter membrane sleeved on the filter rod, a filtration inlet of the filtration tank is communicated with an oil-water separation unit, and the oil-water separation unit is communicated with an oil outlet of the filtration tank. A drain outlet of the filtering tank is communicated with a filter residue treatment unit used for carrying out solid-liquid separation on filter element self-cleaning discharged liquid, a liquid outlet of the filter residue treatment unit is communicated with an oil-water separation unit, oily impurities in the cutting fluid are removed firstly, then solid particle impurities are removed, all the cutting fluid is filtered and recycled, and therefore the cutting fluid can be recycled. The stable and controllable properties of the filtered cutting fluid are effectively ensured, so that the yield and process stability of semiconductor processing are improved.

Description

Technical Field

[0001] This utility model relates to the field of filtration and separation equipment, and in particular to a system for circulating filtration of cutting fluid in semiconductor processing. Background Technology

[0002] In semiconductor wafer fabrication, controlling contaminants in the cutting fluid is a crucial factor affecting processing quality. Current mainstream processes employ centralized circulating filtration systems. These systems partially filter contaminated cutting fluid containing silicon chips and metal particles, then use a centrifuge for initial solid-liquid separation. The treated cutting fluid is then reintroduced into a storage system to mix with untreated liquid for reuse. This filtration model suffers from a critical technical bottleneck: the partial treatment strategy means that untreated contaminants are always present in the circulating system, resulting in uncontrollable physicochemical properties of the cutting fluid (such as viscosity, pH, and particle concentration). With accumulated processing time, this incomplete filtration leads to deterioration of the cutting fluid's dielectric properties, decreased cooling efficiency, and increased risk of secondary contamination. This directly affects the surface roughness and edge chipping rate of the wafer cut surface, and in severe cases, can even cause abnormal wear on diamond wire saws, ultimately impacting the yield and process stability of semiconductor devices. This application proposes a solution to this problem. Summary of the Invention

[0003] Purpose of the utility model: The purpose of this utility model is to provide a system for circulating and filtering cutting fluid in semiconductor processing, which can first remove oily impurities from the cutting fluid, and then remove solid particles such as silicon powder at the micron and submicron levels, thereby achieving complete filtration and recycling of the cutting fluid, and ultimately improving the yield and process stability of the semiconductor wafer processing.

[0004] Technical Solution: The present invention discloses a system for circulating filtration of cutting fluid in semiconductor processing, comprising a precision filtration unit. The precision filtration unit includes at least one filter tank containing several filter elements. Each filter element includes a filter rod and a filter membrane stacked on the filter rod. The filter inlet of the filter tank is connected to an oil-water separation unit. The drain outlet of the filter tank is connected to a filter residue treatment unit for solid-liquid separation of the self-cleaning discharge liquid from the filter elements. The outlet of the filter residue treatment unit is connected to the oil-water separation unit.

[0005] This device separates oily impurities from the cutting fluid through an oil-water separation unit, then separates solid particles from the cutting fluid through a precision filtration unit, and finally provides the filtered cutting fluid back to the machine tool. At the same time, the filter tank is backflushed and cleaned. The cutting fluid with a high solid-liquid ratio generated by the backflushing is introduced into the filter residue treatment unit for separation. The separated liquid is then reintroduced into the oil-water separation unit and the precision filtration unit for filtration and reuse.

[0006] Preferably, the oil-water separation unit includes an oil-water separation chamber, which includes an inlet area for receiving the cutting fluid to be treated, an oil removal area, and an outlet area, wherein the oil removal area is provided with an oil baffle plate.

[0007] The inlet zone introduces cutting fluid, the degreasing zone allows oily impurities to float to the surface, the outlet zone supplies cutting fluid with removed oily impurities to the precision filtration unit, and the baffle plate is designed to collect the floating oily impurities.

[0008] Preferably, the oil baffle includes a bend for collecting floating oil, the bend direction of which corresponds to the flow direction of the cutting fluid, and an oil removal device is provided above the bend.

[0009] The angled structure of the oil baffle is used to collect oily impurities, and the oil removal device is used to remove oily impurities.

[0010] Preferably, the oil removal zone and the liquid outlet zone are separated by a partition, and the partition is provided with an overflow port for connecting the liquid outlet zone; the upper surface of the oil baffle is not lower than the upper surface of the partition, and the lower surface of the oil baffle is lower than the overflow port.

[0011] The overflow port allows the cutting fluid below the oily impurities to enter the outlet area.

[0012] Preferably, the precision filtration unit further includes a dirty liquid tank and a clean liquid tank, which are located below the filter tank and separated by a partition.

[0013] Preferably, a refrigeration device is also included, which is connected to the clean fluid tank and is used to circulate and cool the cutting fluid.

[0014] The refrigeration unit is used to control the temperature of the cutting fluid.

[0015] Preferably, the top of the filter canister is provided with a backflush port for introducing compressed air to perform self-cleaning of the filter element.

[0016] The backflush port is used to introduce external compressed air to backflush and clean the filter element inside the filter tank. The drain pipe guides the high solid-liquid ratio cutting fluid after backflush and cleaning into the filter residue treatment unit.

[0017] Preferably, the filter residue treatment unit includes a backflushing buffer chamber, a centrifuge device, and a submersible pump. The inlet of the backflushing buffer chamber is connected to the drain outlet of the filter tank, and the outlet is connected to the oil-water separation unit. A submersible pump is installed inside the backflushing buffer chamber. The submersible pump draws cutting fluid from the backflushing buffer chamber into the centrifuge device, and the outlet of the centrifuge device is connected to the backflushing buffer chamber.

[0018] The backflush buffer tank is used to temporarily store cutting fluid with a high solid-liquid ratio that has not undergone centrifugation treatment, as well as cutting fluid that has undergone centrifugation treatment. The submersible pump is used to draw the cutting fluid with a high solid-liquid ratio from the backflush buffer tank into the centrifuge device for centrifugation treatment.

[0019] Preferably, a waste residue collection bucket for collecting filter residue is provided below the centrifuge device.

[0020] Waste collection bins are used to collect solid impurities obtained by centrifugation in centrifuge devices.

[0021] Preferably, a water pump is provided on the outside of the backflush buffer chamber, with the inlet of the water pump connected to the backflush buffer chamber and the outlet of the water pump connected to the oil-water separation unit.

[0022] Beneficial effects: Compared with the prior art, this utility model has the following advantages:

[0023] 1. This device first removes oily impurities from the cutting fluid through an oil-water separation unit, and then retains solid particles such as silicon powder through a precision filtration unit. This achieves complete filtration and recycling of the cutting fluid, effectively ensuring that the properties of the filtered cutting fluid are stable and controllable, thereby improving the yield and process stability of semiconductor processing.

[0024] 2. This device blows away the large amount of silicon powder and other solid particles generated during semiconductor processing that adhere to the surface of the filter element through a backflushing process, and then sends them to the filter residue treatment unit for centrifugation. On the one hand, this can ensure that the precision filtration unit can maintain stable operation for a long time, and on the other hand, it can effectively separate the cutting fluid and silicon powder for subsequent recycling. Attached Figure Description

[0025] Figure 1 This is a perspective view of the present invention.

[0026] Figure 2 This is a top sectional view of the present invention.

[0027] Figure 3 This is a three-dimensional structural diagram of the oil-water separation unit and the filter residue treatment unit in this utility model.

[0028] Figure 4 This is a three-dimensional structural diagram of the filter element in this utility model.

[0029] Figure 5 This is a top view of the present invention when a refrigeration device is provided. Detailed Implementation

[0030] The technical solution of this utility model will be further described below with reference to the accompanying drawings.

[0031] Example 1

[0032] See appendix Figures 1-4 The figure shows a system for circulating filtration of cutting fluid in semiconductor processing, which includes a precision filtration unit. The precision filtration unit includes multiple filter tanks 2, and several filter elements are installed in the filter tanks 2. Each filter element includes a filter rod 23 and a filter membrane 22 stacked on the filter rod 23. The filter inlet of the filter tank 2 is connected to an oil-water separation unit, and the drain outlet of the filter tank 2 is connected to a filter residue treatment unit for solid-liquid separation of the self-cleaning discharge liquid of the filter elements. The liquid outlet of the filter residue treatment unit is connected to the oil-water separation unit.

[0033] In this embodiment, the oil-water separation unit includes an oil-water separation chamber 4, which includes an inlet zone 41 for receiving cutting fluid to be treated, an oil removal zone 42, and an outlet zone 43. The oil removal zone 42 is provided with an oil baffle 44. Cutting fluid is introduced through the inlet zone 41, and the oil removal zone 42 allows oily impurities to float to the surface. The outlet zone 43 provides cutting fluid with oily impurities removed to the precision filtration unit. The oil baffle is used to collect the floating oily impurities.

[0034] In this embodiment, the cutting fluid with oily impurities removed is transported from the outlet zone 43 through the clean fluid tank 5 and then into the dirty fluid tank 1 via a pipeline. This arrangement is to prevent interference from external pipelines.

[0035] In this embodiment, the oil baffle 44 includes a bend for collecting floating oil. The bending direction of the bend is consistent with the flow direction of the cutting fluid. An oil removal device 46 is provided above the bend. The bend on the oil baffle 44 is used to collect oily impurities, and the oil removal device 46 is used to remove oily impurities.

[0036] In this embodiment, the degreasing zone 42 and the liquid outlet zone 43 are separated by a partition, and the partition is provided with an overflow port 45 for connecting the liquid outlet zone 43; the upper end face of the oil baffle 44 is not lower than the upper end face of the partition, and the lower end face of the oil baffle 44 is lower than the overflow port 45. The overflow port 45 allows the cutting fluid below the oily impurities to enter the liquid outlet zone 43.

[0037] In this embodiment, the precision filtration unit also includes a dirty liquid tank 1 and a clean liquid tank 5. The clean liquid tank 5 and the dirty liquid tank 1 are located below the filter tank 2 and are separated by a partition. The clean liquid tank 5 is equipped with a supply pump 51 for drawing clean liquid to the machine for use. The dirty liquid tank 1 is equipped with a filter pump 11 for guiding the cutting fluid in the dirty liquid tank 1 into the filter tank 2 for filtration.

[0038] In this embodiment, a backflush port 21 is provided at the top of the filter tank 2. The backflush port 21 is provided to introduce external compressed air to backflush and clean the filter element inside the filter tank 2. A drain pipe 3 is connected to the drain port at the bottom of the filter tank 2. The drain pipe 3 guides the cutting fluid with a high solid-liquid ratio after backflush and cleaning into the filter residue treatment unit.

[0039] In this embodiment, the filter residue treatment unit includes a backflushing buffer tank 6, a centrifuge device 7, and a submersible pump 8. The inlet of the backflushing buffer tank 6 is connected to the drain outlet of the filter tank 2, and the outlet is connected to the oil-water separation unit. The submersible pump 8 is installed inside the backflushing buffer tank 6. The submersible pump 8 draws the cutting fluid from the backflushing buffer tank 6 into the centrifuge device 7. The outlet of the centrifuge device 7 is connected to the backflushing buffer tank 6. The backflushing buffer tank 6 is used to temporarily store cutting fluid with a high solid-liquid ratio that has not undergone centrifugation treatment as well as cutting fluid that has undergone centrifugation treatment. The submersible pump 8 is used to draw the cutting fluid with a high solid-liquid ratio from the backflushing buffer tank 6 into the centrifuge device 7 for centrifugation treatment.

[0040] In this embodiment, a waste residue collection bucket 71 is provided below the centrifuge device 7 for collecting filter residue and solid impurities obtained by centrifugation by the centrifuge device 7.

[0041] In this embodiment, a water pump 61 is provided on the outside of the backflush buffer chamber 6. The inlet of the water pump 61 is connected to the backflush buffer chamber 6, and the outlet of the water pump 61 is connected to the oil-water separation unit. The water pump 61 is provided to reintroduce the centrifuged cutting fluid into the oil-water separation unit for further filtration.

[0042] Example 2

[0043] See appendix Figure 5 In this embodiment, a refrigeration device 9 is included. The refrigeration device 9 is a refrigeration machine. The refrigeration machine is connected to the clean liquid tank 5. The cutting fluid is drawn from the clean liquid tank 5 to the refrigeration machine for cooling through the refrigeration machine circulation pump 91. After cooling is completed, it is transported back to the clean liquid tank 5.

[0044] Example 3

[0045] When the device is working, the cutting fluid enters the inlet area 41 of the oil-water separation chamber 4. After floating for a period of time, it enters the degreasing area 42 through the corner. Under the action of the oil baffle 44 in the degreasing area 42, the floating oily impurities are collected at the corner of the oil baffle 44. The degreasing device 46 above the corner of the oil baffle 44 scrapes off the oily impurities from the liquid surface. After degreasing, the cutting fluid enters the outlet area 43 through the overflow plate 45 and then enters the dirty liquid tank 1 of the precision filter unit. Under the action of the filter pump 11, the cutting fluid is introduced into the filter tank 2. Under the action of the filter element in the filter tank 2, solid particles are intercepted outside the filter membrane 22. The clean cutting fluid flows out through the hollow part of the filter rod 23 and is discharged from the filter tank 2, entering the clean liquid tank 5. The liquid supply pump 51 in the clean liquid tank 5 draws the cutting fluid in the clean liquid tank 5 to the machine for use.

[0046] After a period of use, a large number of solid particles remain on the outside of the filter membrane 22. At this time, the backflush port 21 introduces an external compressed air source to backflush and clean the filter membrane 22. The cutting fluid with a high solid-liquid ratio in the filter tank 2 is then discharged into the backflush buffer chamber 6 in the filter residue treatment unit through the drain port into the drain pipe 3. At this time, the submersible pump 8 is started to draw the cutting fluid in the backflush buffer chamber 6 into the centrifuge device 7 for centrifugation. After centrifugation, the solid particles are discharged into the waste residue collection bucket 71, and the liquid cutting fluid is discharged back into the backflush buffer chamber 6. After centrifugation, the water pump 61 is started to transport the cutting fluid in the backflush buffer chamber 6 to the oil-water separation chamber 4 for further filtration and recycling.

Claims

1. A system for circulating and filtering cutting fluid in semiconductor processing, comprising a precision filtration unit, characterized in that: The precision filtration unit includes at least one filter tank (2), in which several filter elements are arranged. Each filter element includes a filter rod (23) and a filter membrane (22) stacked on the filter rod (23). The filter inlet of the filter tank (2) is connected to an oil-water separation unit. The drain outlet of the filter tank (2) is connected to a filter residue treatment unit for solid-liquid separation of the filter element self-cleaning discharge liquid. The liquid outlet of the filter residue treatment unit is connected to the oil-water separation unit.

2. The system for circulating and filtering cutting fluid in semiconductor processing according to claim 1, characterized in that: The oil-water separation unit includes an oil-water separation chamber (4), which includes an inlet area (41) for receiving cutting fluid to be processed, an oil removal area (42) and an outlet area (43), wherein the oil removal area (42) is provided with an oil baffle (44).

3. A system for circulating and filtering cutting fluid in semiconductor processing according to claim 2, characterized in that: The oil baffle (44) includes a bend for collecting floating oil, the bend direction of which corresponds to the flow direction of the cutting fluid, and an oil removal device (46) is provided above the bend.

4. A system for circulating and filtering cutting fluid in semiconductor processing according to claim 2, characterized in that: The oil removal zone (42) and the liquid outlet zone (43) are separated by a partition, and the partition is provided with an overflow port (45) for connecting the liquid outlet zone (43); the upper end face of the oil baffle (44) is not lower than the upper end face of the partition, and the lower end face of the oil baffle (44) is lower than the overflow port (45).

5. A system for circulating and filtering cutting fluid in semiconductor processing according to claim 1, characterized in that: The precision filtration unit also includes a dirty liquid tank (1) and a clean liquid tank (5). The clean liquid tank (5) and the dirty liquid tank (1) are located below the filter tank (2) and are separated by a partition.

6. A system for circulating and filtering cutting fluid in semiconductor processing according to claim 5, characterized in that: It also includes a refrigeration unit (9), which is connected to the clean liquid tank (5) for circulating and cooling the cutting fluid.

7. A system for circulating and filtering cutting fluid in semiconductor processing according to claim 1, characterized in that: The top of the filter tank (2) is provided with a backflush port (21) for introducing compressed air to perform self-cleaning of the filter element.

8. A system for circulating and filtering cutting fluid in semiconductor processing according to claim 1, characterized in that: The filter residue treatment unit includes a backflushing buffer chamber (6), a centrifuge device (7), and a submersible pump (8). The inlet of the backflushing buffer chamber (6) is connected to the drain outlet of the filter tank (2), and the outlet is connected to the oil-water separation unit. A submersible pump (8) is installed inside the backflushing buffer chamber (6). The submersible pump (8) draws cutting fluid from the backflushing buffer chamber (6) into the centrifuge device (7), and the outlet of the centrifuge device (7) is connected to the backflushing buffer chamber (6).

9. A system for circulating and filtering cutting fluid in semiconductor processing according to claim 8, characterized in that: Below the centrifuge device (7) is a waste residue collection bucket (71) for collecting filter residue.

10. A system for circulating and filtering cutting fluid in semiconductor processing according to claim 8, characterized in that: A water pump (61) is provided on the outside of the backflush buffer chamber (6). The inlet of the water pump (61) is connected to the backflush buffer chamber (6), and the outlet of the water pump (61) is connected to the oil-water separation unit.

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