JP2022089048A - Machining waste liquid treatment device - Google Patents

Abstract

To provide a machining waste liquid treatment device which improves a life of a filtration filter arranged on the machining waste liquid treatment device, and can avoid promotion of consumption of an ion exchange resin.SOLUTION: A machining waste liquid treatment device includes at least a waste water tank 81, a filtration part 83 for filtering waste water fed from the waste water tank 81, a clean water tank 84 for storing clean water purified by the filtration part 83, an ultraviolet irradiation unit 85 for irradiating the clean water fed from the clean water tank 84 with ultraviolet rays, and destroying an organic matter, and an ion exchange resin part 87 for producing pure water from the clean water fed from the ultraviolet irradiation unit 85, and has a machining chip removal unit 60 that is arranged between a machining device and the waste water tank 81, and bonds machining chips included in the waste water to a recovery part by an electrophoresis method, and removes the machining chips.SELECTED DRAWING: Figure 2

Description

The present invention relates to a processing waste liquid treatment device that generates pure water from waste water discharged from the processing device.

A wafer having a plurality of devices such as ICs and LSIs partitioned by a scheduled division line and formed on the front surface is ground on the back surface by a grinding device and used for electric devices such as mobile phones and personal computers.

Further, the present applicant has proposed a processing waste liquid treatment device that removes processing waste from wastewater discharged from a grinding device and a dicing device to generate pure water (see, for example, Patent Document 1). When the processing waste liquid treatment device is arranged for treating the wastewater of the grinding device, the wastewater discharged from the grinding device contains a large amount of processing waste (grinding waste), so that the processing waste liquid treatment is performed. There is a problem that the life of the filtration filter constituting the device is significantly shortened, the filtration filter must be replaced frequently, and it is uneconomical.

To solve the above problem, an apparatus (see, for example, Patent Document 2) that collects processing waste (for example, silicon fine particles) contained in the processing waste liquid discharged by grinding a wafer by an electrophoresis method and purifies the processing waste liquid. Proposed by the present applicant, it is conceivable to extend the life of the filtration filter disposed in the processing waste liquid treatment device by applying the device to the above-mentioned processing waste liquid treatment device.

Japanese Unexamined Patent Publication No. 2009-190128 Japanese Unexamined Patent Publication No. 2013-121637

By the way, in order to effectively recover the processing waste by the electrophoresis method, CO ₂ may be mixed in the processing waste liquid in order to adjust the discharged processing waste liquid to high conductivity (low electrical resistivity). It has been. However, in the processing waste liquid treatment equipment, the ion exchange resin disposed to generate pure water from fresh water has CO ₂ contained in the liquid to be subjected to the ion exchange treatment, which accelerates the consumption of the ion exchange resin. This time, there is a problem that the life of the ion exchange resin is shortened.

The present invention has been made in view of the above facts, and its main technical problem is to improve the life of the filtration filter disposed in the processing waste liquid treatment apparatus and to avoid the acceleration of consumption of the ion exchange resin. It is an object of the present invention to provide a processing waste liquid treatment apparatus which can be performed.

In order to solve the above-mentioned main technical problem, according to the present invention, it is a processing wastewater treatment device that generates pure water from the wastewater discharged from the processing device, and is a drainage tank that stores the wastewater and is sent out from the drainage tank. A filtration unit that filters wastewater, a fresh water tank that stores fresh water purified by the filtration unit, an ultraviolet irradiation unit that irradiates the fresh water sent out from the fresh water tank with ultraviolet rays to destroy organic substances, and the ultraviolet irradiation unit. It contains at least an ion exchange resin part that generates pure water from the fresh water sent out from, and is disposed between the processing device and the drainage tank, and the processing waste contained in the wastewater adheres to the recovery part by electrophoresis. A machined waste removing unit for removing the machined waste and a CO ₂ supply unit for supplying CO ₂ to the wastewater supplied to the machined waste removing unit are arranged, and the ion exchange resin unit is provided from the machined waste removing unit. A processing waste liquid treatment apparatus is provided in which a shower means for reducing the concentration of CO ₂ contained in waste water is provided on the route leading to.

The processed waste liquid treatment apparatus of the present invention includes a drainage tank for storing wastewater, a filtering unit for filtering the wastewater sent out from the drainage tank, a freshwater tank for storing fresh water purified by the filtering unit, and the freshwater tank. The processing apparatus and the processing apparatus include at least an ultraviolet irradiation unit that irradiates fresh water discharged from the water with ultraviolet rays to destroy organic substances, and an ion exchange resin unit that generates pure water from the fresh water delivered from the ultraviolet irradiation unit. CO ₂ is supplied to the work waste removal unit that is arranged between the drain tank and the work waste contained in the waste water and adheres to the recovery unit to remove it, and the waste water supplied to the work waste removal unit. A CO ₂ supply unit and a shower means for reducing the concentration of CO ₂ contained in the waste water are arranged in the path from the processing waste removing unit to the ion exchange resin unit. The recovery efficiency of the waste removal unit can be improved, the life of the filtration unit that filters the wastewater sent from the drainage tank can be improved, and the consumption of the ion exchange resin disposed in the ion exchange resin unit can be reduced. can.

It is a perspective view which shows the outline of the grinding apparatus and the processing waste liquid treatment apparatus of this embodiment. It is a perspective view which shows the detail of the structure of the processing waste liquid processing apparatus. It is sectional drawing of the processing scrap removal unit of this embodiment. It is a schematic diagram which shows the embodiment of the shower means of this embodiment in a partial cross section.

Hereinafter, embodiments relating to the processing waste liquid treatment apparatus configured based on the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a perspective view showing an outline of the machining waste liquid treatment device 5 of the present embodiment and the grinding device 1 which is a machining device to which the machining waste liquid treatment device 5 is applied.

The grinding device 1 grinds the holding means 2 disposed in the device housing 10, the grinding means 3 for grinding the back surface Wb of the wafer W held by the holding means 2, and the grinding means 3 in the Z-axis direction (vertical direction). It is provided with at least an elevating means 4 for elevating and lowering. The wafer W processed by the grinding device 1 is, for example, a silicon wafer, and as shown on the left side in the figure, a plurality of devices not shown are formed on the lower surface side of the wafer W (in the present embodiment, a plurality of devices (not shown) are formed. The protective tape T is attached to the front surface side), and is held by the holding means 2 with the back surface Wb side exposed upward.

The holding means 2 includes a chuck table 21 having a holding surface 21a defined by an X-axis direction and a Y-axis direction orthogonal to the X-axis direction and substantially forming a horizontal plane. The chuck table 21 is configured to be rotatable by a rotary driving means (not shown), and the holding surface 21a is configured to have a breathable member. The chuck table 21 is connected to a suction means (not shown), and by operating the suction means, a suction negative pressure is supplied to the holding surface 21a. The chuck table 21 can be moved to an arbitrary position in the X-axis direction by an X-axis moving means (not shown) housed inside the device housing 10.

The grinding means 3 rotates a rotating shaft 31, a grinding wheel 32 arranged at the lower end of the rotating shaft 31, a plurality of grinding grinds 33 arranged in an annular shape on the lower surface of the grinding wheel 32, and the rotating shaft 31. It includes at least an electric motor 34 and a Z-axis moving base 35 that supports the grinding means 3 and is movably supported in the Z-axis direction indicated by the arrow Z in the figure. The Z-axis moving base 35 can be moved to an arbitrary position in the Z-axis direction by the elevating means 4. The grinding device 1 includes control means (not shown), and its operation is controlled by a control signal instructed by the control means.

In the grinding apparatus 1, when the wafer W is sucked and held on the chuck table 21 and the back surface Wb of the wafer W is ground by the grinding means 3, the grinding water supplied to the lower surface side of the grinding wheel 32 during the grinding process contains silicon fine particles and the like. The drainage L1 mixed with the machining chips is generated and discharged from the drain hose 12 arranged in the apparatus housing 10 of the grinding apparatus 1. The drainage L1 discharged from the drain hose 12 is sent to the processing waste liquid treatment device 5 by the operation of the pump P1, filtered and refined to generate pure water L9, and the rotary shaft 31 of the grinding means 3 It is supplied to the upper end 31a, guided to the lower surface of the grinding wheel 32 via a supply path (not shown) formed inside the rotating shaft 31, and used again as grinding water.

The processing waste liquid treatment device 5 is included in the CO ₂ supply unit 50 that supplies CO ₂ to the waste water L1 discharged from the grinding device 1 and the waste water L2 that is discharged from the CO ₂ supply unit 50 and has an increased CO ₂ concentration. A machined waste removing unit 60 that removes dust by an electrophoresis method, and a pure water generator 80 that further purifies the wastewater L3 from which the processed waste discharged from the machined waste removing unit 60 has been removed to generate pure water. It is equipped with. In addition to FIG. 1, the details of the processing waste liquid treatment apparatus 5 of the present embodiment will be described with reference to FIG. 2.

Grinding is performed in the grinding device 1, and the drainage L1 discharged from the drain hose 12 is introduced into the CO ₂ supply unit 50 via the path 101 as shown in FIG. The CO ₂ supply unit 50 includes a CO ₂ storage tank 51 and a mixer 52. The wastewater L1 introduced into the CO ₂ supply unit 50 passes through the mixer 52, so that CO ₂ supplied from the CO ₂ storage tank 51 is mixed. By increasing the CO ₂ concentration of the waste water L1, the waste water L2 having a low electrical resistivity and an increased conductivity is sent to the processing waste removing unit 60 via the path 102. In addition to FIG. 2, the outline of the machined waste removing unit 60 will be described with reference to FIG.

FIG. 3 shows a schematic cross-sectional view of the machining debris removing unit 60. As shown in the figure, the machined waste removing unit 60 connects the pipe 61b by the action of the tank 61 for accommodating the drainage L2 introduced from the introduction port 60a via the path 102 and the pump 61a arranged in the tank 61. It is provided with a processing waste collecting means 63 into which the drainage L2 is introduced through the pipe. The work waste collecting means 63 includes a water storage tank 63a for storing the wastewater L2, a work waste separation mechanism 64 in which a part thereof is incorporated in the water storage tank 63a, and a work waste recovery mechanism 65.

The processing waste separation mechanism 64 separates the processing waste D containing fine particles of silicon generated when grinding the wafer W from the drainage L2 stored in the water storage tank 63a. The machining waste separation mechanism 64 is arranged above the plurality of cathode plates 64a arranged in the water storage tank 63a, the plurality of lower rollers 64b arranged between the cathode plates 64a, and the cathode plates 64a. The plurality of upper rollers 64c, the electric motor 64d above the upper roller 64c and arranged on the left side in the figure, the drive roller 64e driven by the electric motor 64d, and the same drive roller 64e. As shown in the figure, the driven roller 64f arranged on the right side in the figure and each of the above-mentioned rollers are hung around the height of the driven roller D and functions as a collecting unit for adsorbing and collecting the machining waste D. It is provided with 64 g of an endless belt and a DC power supply 64h for applying a negative (−) voltage to the cathode plate 64a and a positive (+) voltage to the endless belt 64 g. The endless belt 64 g is made of a conductive metal (for example, a stainless steel plate). The periphery of the cathode plate 64a and the lower roller 64b around which the endless belt 64g is hung is flooded in the drainage L2 stored in the water storage tank 63a, and the processing waste D is contained in the lower part of the water storage tank 63a. A discharge port 60b for discharging the drained water L3 after being removed is provided.

The machining waste recovery mechanism 65 energizes the cathode plate 64a and the endless belt 64g by the above-mentioned DC power supply 64h, which includes the peeling portion 65a and the recovery box 65b, and operates the drive motor 64d to point the endless belt 64g as an arrow. By rotating in the direction indicated by A, the work scrap D charged negatively (-) by electrophoresis is repelled from the cathode plate 64a charged negatively (-), and the endless belt charged positively (+). It is adsorbed to 64 g. The work waste D adsorbed on the endless belt 64g is carried by the endless belt 64g, peeled off by the peeling portion 65a on the collection box 65b, dropped on the collection box 65b, and collected. In this way, the work waste D is removed from the drainage L2 stored in the water storage tank 63a. In the present embodiment, the heater 65c is also arranged at a position adjacent to the collection box 65b, and the processing waste D collected in the collection box 65b is dried by the action of the heater 65c. Further, in the above-described embodiment, 64 g of a metal endless belt is disposed as a recovery unit for adsorbing and recovering the processing waste D, but the present invention is not limited to this, and the present invention is not limited to this and is connected to the anode of the DC power supply 64h. It may be an electrode plate that is positively charged (+). When the electrode plate is used, the electrode plate is inserted between the cathode plates 64a in the water storage tank 63a to adsorb the processing waste D in the drainage L2, and then the electrode plate is removed from the water storage tank 63a. By taking it out, the processing waste D can be recovered from the wastewater L2.

Returning to FIG. 2 and continuing the explanation, the drainage L3 from which the work piece D has been removed by the action of the work piece removal unit 60 is discharged from the discharge port 60b of the work piece removal unit 60 by the action of the pump P2 on the path 103. , Is sent to the pure water generator 80. The pure water generator 80 includes a shower means 70, a drainage tank 81 for storing the drainage L3 discharged from the shower means 70, a filtering unit 83 for filtering and purifying the drainage L4 discharged from the drainage tank 81, and filtration. A fresh water tank 84 that stores the fresh water L5 purified by the unit 83, an ultraviolet irradiation unit 85 that irradiates the fresh water L5 sent out from the fresh water tank 84 with ultraviolet rays to destroy organic substances contained in the fresh water L5, and an ultraviolet irradiation unit 85. It is provided with at least an ion exchange resin unit 87 that produces pure water L7 from the fresh water L6 produced by. Further, in the present embodiment, in addition to the above configuration, filtration is performed by a precision filter 88 for removing the remaining substances and the like by destroying the organic substances remaining in the pure water L7 sent out from the ion exchange resin unit 87, and the precision filter 88. It is provided with a temperature controller 89 that supplies the discharged pure water L8 to the grinding device 1 as pure water L9 adjusted to an appropriate temperature as grinding water.

In the illustrated embodiment, the filtration unit 83 includes a first filtration filter 831 and a second filtration filter 832 so that the operation of the filtration unit 83 can be continued without stopping the operation of the pure water generator 80. A flow path switching valve 82 is provided. When clogging of one of the filtration filters is detected, the flow of the drainage L4 guided from the path 104 is guided to the other filtration filter that is not clogged, and the filtration filter in which the clogging is detected is used as a new filtration filter. Replace with. The clogging of the filtration filter of the filtration unit 83 can be detected by disposing a pressure detecting means (not shown) on the path 104. The ion exchange resin unit 87 includes a first ion exchange resin unit 871 and a second ion exchange resin unit 872 so that the operation of the ion exchange resin unit 87 can be continued without stopping the operation of the pure water generator 80. Is provided with a flow path switching valve 86. For example, when the consumption of the second ion exchange resin unit 872 is detected, the flow of fresh water L6 guided from the path 107 is guided to the first ion exchange resin unit 871 that is not consumed, and the second ion exchange resin unit is used. Replace 872 with a new ion exchange resin. The degree of consumption of the ion exchange resin can be detected by disposing a resistivity value detecting means (not shown) on the path 108 and determining the detection value detected by the resistivity value detecting means. It is possible.

In addition to FIG. 2, the shower means 70 of the present embodiment described above will be further described with reference to FIG. As shown in FIG. 4, the shower means 70 includes a shower head 72 that discharges the drainage L3 guided from the path 103. The lower end of the shower head 72 is formed in a disk shape (see FIG. 2), and a plurality of fine holes are formed on the lower surface 74 of the shower head 72 over the entire surface. The lower surface 74 of the shower head 72 is arranged above the water surface in the drain tank 81, and the drainage L3 supplied via the path 103 by the operation of the pump P2 is drained from the lower surface 74 of the shower head 72. It is discharged like a shower toward the inside of 81.

The processing waste liquid treatment apparatus 5 of the present embodiment has substantially the same configuration as described above, and its function and action / effect will be described more specifically.

In the grinding device 1, the back surface Wb of the wafer W sucked and held by the chuck table 21 of the holding means 2 is ground by the grinding means 3, and the drainage L1 of the grinding water used for grinding is drained by the action of the pump P1. It is guided to the CO ₂ supply unit 50 via the path 101 including the hose 12. As described with reference to FIG. 2, CO ₂ is mixed with the waste water L1 by the action of the CO ₂ supply unit 50, and the CO ₂ concentration is increased, so that, for example, the electrical resistivity is from 0.3 MΩ · cm to 0. It can be reduced to 2 MΩ · cm. The waste water L2 having an increased CO ₂ concentration is guided to the work waste removing unit 60 via the path 102, and the work waste D mainly composed of silicon fine particles contained in the waste water L2 is removed. As described above, in the wastewater L2, the CO ₂ concentration is increased and the electrical resistivity is adjusted, so that the recovery rate in the work waste separation mechanism 64 is improved, and the work waste D is efficiently recovered. In the processing waste separation mechanism 64, the processing waste D having a particle size corresponding to the voltage value applied by the DC power supply 64h is removed at a constant ratio, but all the processing waste D contained in the wastewater L2 is removed. Not that.

Next, the wastewater L3 from which the processing waste D has been removed to some extent by the processing waste removing unit 60 is guided to the drainage tank 81 of the pure water generator 80 via the shower means 70. As described above, the drainage L3 is guided to the drainage tank 81 via the shower means 70 and discharged from the shower head 72, so that CO ₂ is released from the drainage L3 and in the drainage tank 81. After being stirred, CO ₂ in the waste water L3 is released to reduce the concentration of CO ₂ .

The drainage L4 whose CO ₂ concentration has been reduced from the drainage tank 81 by the action of the pump P3 on the path 104 connected to the drainage tank 81 is removed from the drainage tank 81 via the flow path switching valve 82 to one of the filtration filters of the filtration unit 83. For example, it is guided to the first filtration filter 831. In the first filtration filter 831, substances and the like that are not removed by the processing waste removing unit 60 and remain in the wastewater L4 are filtered, and fresh water L5 is discharged from the filtration unit 83. The fresh water L5 discharged from the filtration unit 83 is guided to the fresh water tank 84 via the path 105 and stored.

The fresh water L5 stored in the fresh water tank 84 is introduced into the ultraviolet irradiation unit 85 via the path 106 by the action of the pump P4. The ultraviolet irradiation unit 85 irradiates the fresh water L5 with ultraviolet rays to destroy organic substances and the like remaining in the fresh water L5 to generate sterilized fresh water L6. The sterilized fresh water L6 discharged from the ultraviolet irradiation unit 85 is guided to the ion exchange resin unit 87, for example, the first ion exchange resin unit 871 via the path 107 and the flow path switching valve 86. In the fresh water L6 guided to the first ion exchange resin unit 871, the charged substance (ion) contained in the fresh water L6 is removed by the ion exchange action, and pure water L7 is generated from the fresh water L6.

The pure water L7 discharged from the ion exchange resin unit 87 into the path 108 is guided by the precision filter 88, and impurities mixed in the filtration unit 83 and subsequent parts remaining in the pure water L7 and organic substances generated in the ultraviolet irradiation unit 85. Decompositions etc. are removed. The pure water L8 discharged from the precision filter 88 is guided to the temperature controller 89 via the path 109, adjusted to a temperature suitable for grinding water used in the grinding apparatus 1, and functions as a pure water supply means. It is introduced into the grinding means 3 of the grinding apparatus 1 again by the action of the pump built in the controller 89 (not shown) or the pump P5 (see FIG. 1) on the path 110 connected to the temperature controller 89. Used as grinding water. The precision filter 88 and the temperature controller 89 described above are optional and are arranged as necessary.

According to the above-described embodiment, between the grinding device 1 and the drain tank 81 of the machining waste liquid treatment device 5, the machining waste removing unit 60 for removing the machining waste D and the drainage L1 supplied to the machining waste removing unit 60 By arranging the CO ₂ supply unit 50 that supplies CO ₂ to the wastewater, the efficiency of collecting the work waste D in the work waste removal unit 60 is improved, and the filtration unit that filters the wastewater sent out from the drainage tank 81. The life of the 83 filtration filters (first filtration filter 831 and second filtration filter 832) is improved. Since the shower means 70 for reducing the concentration of CO ₂ contained in the wastewater is arranged in the path from the drainage tank 81 to the ion exchange resin portion 87, the fresh water L6 guided to the ion exchange resin portion 87 is provided. The CO ₂ concentration of the ion exchange resin portion 87 can be reduced, and the consumption of the ion exchange resin portion 87 can be reduced.

In the above-described embodiment, the shower means 70 is arranged on the path 103 for guiding the drainage L3 discharged from the processing waste removing unit 60 to the drainage tank 81 at a position facing the drainage tank 81. The invention is not limited to this, and if it is a path arranged between the work waste removal unit 60 and the ion exchange resin portion 87 (for example, paths 104 to 107), it can be arranged on any path. can. In that case, it is necessary to separately dispose a tank for temporarily storing the drainage or fresh water discharged from the shower head 72 together with the shower means 70. However, when the shower means 70 is arranged on the path 105, CO ₂ can be discharged from the fresh water L5 discharged from the shower means 70 by opening the ceiling of the fresh water tank 84.

Further, in the above-described embodiment, an example in which the processing waste liquid treatment device 5 is applied to the grinding device 1 is shown, but the present invention is not limited to this, and other processing devices using pure water as the processing water (for example). , Dicing device) can also be applied.

1: Grinding device 2: Holding means 21: Chuck table 21a: Holding surface 3: Grinding means 31: Rotating shaft 32: Grinding wheel 33: Grinding grindstone 34: Electric motor 35: Z-axis moving base 4: Z-axis moving means 5 : Processing waste liquid treatment device 10: Equipment housing 12: Drain hose 50: CO ₂ supply unit 60: Processing waste removing unit 60a: Introducing port 60b: Discharge port 61: Tank 61a: Pump 63: Processing waste collecting means 63a: Water storage tank 64 : Machining waste separation mechanism 64a: Cathode plate 64b: Lower roller 64c: Upper roller 64d: Electric motor 64e: Drive roller 64f: Driven roller 64g: Endless belt 64h: DC power supply 65: Machining waste collection mechanism 70: Shower means 72: Shower Head 80: Pure water generator 81: Drainage tank 82: Flow path switching valve 83: Filter unit 831: First filtration filter 832: Second filtration filter 84: Fresh water tank 85: Ultraviolet irradiation unit 86: Flow path switching valve 87: Ion exchange resin part 871: 1st ion exchange resin part 872: 2nd ion exchange resin part 88: Precision filter 89: Temperature controller 101 to 110: Path D: Machining waste W: Weha T: Protective tape P1 to P5: Pump

Claims (1)

It is a processing waste liquid treatment device that generates pure water from the wastewater discharged by the processing device.
The drainage tank that stores the wastewater, the filter unit that filters the wastewater sent out from the drainage tank, the fresh water tank that stores the fresh water purified by the filter unit, and the fresh water sent out from the fresh water tank are irradiated with ultraviolet rays. It contains at least an ultraviolet irradiation unit that destroys organic substances and an ion exchange resin portion that generates pure water from fresh water sent out from the ultraviolet irradiation unit.
The processing waste removal unit, which is arranged between the processing equipment and the drainage tank and removes the processing waste contained in the wastewater by adhering it to the collection unit by electrophoresis, and the wastewater supplied to the processing waste removal unit. A CO ₂ supply unit that supplies CO ₂ is provided, and a shower means that reduces the concentration of CO ₂ contained in the wastewater is arranged in the path from the processing waste removing unit to the ion exchange resin unit. Processing waste liquid treatment equipment to be performed.

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