Processing water supply device

Abstract

To provide a processing-water supply device that is low in a cost and long in a service life.SOLUTION: A processing-water supply device 2 includes: a water storage tank 6 that stores waste liquid used in a processing device 4; processing-water purifying means 8 that purifies the waste liquid in the water storage tank 6 into processing water; a waste liquid supply passage 12 including a centrifugal pump 10 that feeds the waste liquid stored in the water storage tank 6 to the processing-water purifying unit 8; a processing-water supply passage 16 including a supply pump 14 that supplies the processing water fed from the processing-water purifying unit 8 to the processing device 4; and control means 18. The centrifugal pump 10 has capacities to allow a pressure for feeding the waste liquid to the processing-water purifying means 8 and to allow the flow rate of the processing water, fed from the processing-water purifying unit 8, to be equal to the flow rate of the processing water used in the processing device 4. The supply pump 14 has a capacity to allow the pressure and the flow rate for supplying the processing water, sent out from the processing-water purifying unit 8, to the processing device 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a machining water supply device for supplying machining water to a machining device.

Background Art

[0002] A wafer on which a plurality of devices such as ICs and LSIs are partitioned by a dividing line and formed on the surface is ground on the back surface by a grinding device to be processed to a predetermined thickness, and then divided into individual device chips by a dicing device. Each of the divided device chips is used in electrical devices such as mobile phones and personal computers.

[0003] A grinding device generally includes a chuck table for holding a wafer, a grinding means rotatably mounted with a grinding wheel having an annular grinding stone for grinding the wafer held on the chuck table, a grinding water supply means for supplying grinding water (pure water) to the grinding wheel, and a cleaning means for cleaning the wafer, and can grind the wafer with high precision (see, for example, Patent Document 1).

[0004] A dicing device generally includes a chuck table for holding a wafer, a cutting means rotatably mounted with a cutting blade for cutting the wafer held on the chuck table, a cutting water supply means for supplying cutting water (pure water) to the cutting blade, and a cleaning means for cleaning the wafer, and can divide the wafer into individual device chips with high precision (see, for example, Patent Document 2).

[0005] Machining water (pure water) such as grinding water, cutting water, and cleaning water is sent from a pure water facility (water source) to a storage tank and stored in the storage tank. Then, the machining water stored in the storage tank is sent to a temperature adjusting means by a pump, adjusted to a desired temperature, and then supplied to a machining device such as a grinding device or a dicing device.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, there is a problem that it is uneconomical to discard the used processed water after using relatively expensive pure water as the processed water. This is especially true in areas where it is difficult to obtain pure water.

[0008] Therefore, the applicant has proposed a processed water waste liquid treatment device for purifying pure water from used processed water (waste liquid) (see, for example, Japanese Unexamined Patent Application Publication No. 2009-190128). However, there is room for improvement in terms of the cost and lifespan of the device.

[0009] An object of the present invention is to provide a processed water supply device with low cost and long lifespan.

Means for Solving the Problems

[0010] According to the present invention, there is provided the following processed water supply device for solving the above problems. That is, "A processed water supply device for supplying processed water to a processing device, a water storage tank for storing waste liquid used in the processing device, processed water purification means for purifying the waste liquid in the water storage tank into processed water, a waste liquid supply path including a centrifugal pump for sending the waste liquid stored in the water storage tank to the processed water purification means, a processed water supply path including a supply pump for supplying the processed water sent out from the processed water purification means to the processing device, control means, and the centrifugal pump has the ability to allow the pressure for sending the waste liquid to the processed water purification means and to allow the flow rate of the processed water sent out from the processed water purification means to be the flow rate of the processed water used in the processing device, A processing water supply device is provided, where the supply pump has the ability to allow the pressure and flow rate of the processing water sent out from the processing water purification means to be supplied to the processing device.

[0011] Preferably, a return path is arranged to be connected to the processing water supply path between the processing water purification means and the supply pump to return excess processing water to the water storage tank. The supply pump can supply processing water to two or more processing devices.

[0012] The processing water purification means preferably includes a filter for filtering waste liquid to generate clean water, an ultraviolet irradiator for destroying organic substances mixed in the clean water, a temperature controller, and an ion exchange resin for generating pure water from the clean water. A precision filter may be arranged after the supply pump.

[0013] When the flow rate of the processing water sent out from the processing water purification means exceeds the flow rate of the processing water used in the processing device, it is preferable for the control means to reduce the rotation speed of the centrifugal pump to appropriately adjust the flow rate of the processing water.

Advantages of the Invention

[0014] The processing water supply device of the present invention includes a water storage tank for storing waste liquid used in the processing device, processing water purification means for purifying the waste liquid in the water storage tank into processing water, a waste liquid supply path provided with a centrifugal pump for sending the waste liquid stored in the water storage tank into the processing water purification means, a processing water supply path provided with a supply pump for supplying the processing water sent out from the processing water purification means to the processing device, and control means, the centrifugal pump has the ability to allow the pressure for sending waste liquid into the processing water purification means and to allow the flow rate of the processing water sent out from the processing water purification means to be the flow rate of the processing water used in the processing device, Since the supply pump has the ability to allow the pressure and flow rate of the processed water sent out from the processed water purification means to be supplied to the processing apparatus, a pure water facility becomes unnecessary, which is economical. Further, in the processed water supply apparatus of the present invention, in addition to including a centrifugal pump, which is most preferable as a pump for sending used processed water, in which foreign matters such as processed chips generated during processing and abrasive grains that have fallen off from the processing tool during processing are mixed, from the water storage tank to the processed water purification means, by including a supply pump for supplying the processed water purified into pure water to the processing apparatus, instead of a large centrifugal pump that allows the pressure for sending waste liquid into the processed water purification means and allows the pressure of the processed water sent out from the processed water purification means to be supplied to the processing apparatus, a centrifugal pump with a small capacity and low cost can be used. Furthermore, in the present invention, since a centrifugal pump and a supply pump are included, the pressure of the centrifugal pump can be reduced, so the pressure applied to the processed water purification means becomes small, and thus the deterioration of the processed water purification means can be delayed. Therefore, according to the present invention, cost reduction and extended service life can be achieved.

Brief Description of the Drawings

[0015]

Figure 1

Embodiments for Carrying Out the Invention

[0016] Hereinafter, a preferred embodiment of the processed water supply apparatus according to the present invention will be described with reference to the drawings.

[0017] (Processed Water Supply Apparatus 2) The processed water supply apparatus 2 shown in FIG. 1 is an apparatus for supplying processed water to the processing apparatus 4. The processed water supply apparatus 2 includes a water storage tank 6 for storing waste liquid used in the processing apparatus 4, processed water purification means 8 for purifying the waste liquid in the water storage tank 6 into processed water, a waste liquid supply path 12 including a centrifugal pump 10 for sending the waste liquid stored in the water storage tank 6 to the processed water purification means 8, a processed water supply path 16 including a supply pump 14 for supplying the processed water sent out from the processed water purification means 8 to the processing apparatus 4, and a control means 18.

[0018] (Processing device 4) Examples of the processing device 4 include a grinding device that grinds a workpiece such as a wafer, and a dicing device that cuts a workpiece such as a wafer. Although not shown, the processing device 4 is provided with a plurality of processing water injection ports such as an injection port for injecting processing water for cooling and cleaning toward a cutting tool or a workpiece when processing the workpiece, and an injection port for injecting cleaning processing water onto the workpiece when cleaning the workpiece. Note that the number of processing devices 4 supplied with processing water from the processing water supply device 2 may be one or two or more.

[0019] (Water storage tank 6) The water storage tank 6 is connected to the processing device 4 via the waste liquid discharge path 20. For this reason, the waste liquid of the processing water used in the processing device 4 is sent to the water storage tank 6 via the waste liquid discharge path 20. Note that foreign matters such as processing chips generated during processing and abrasive grains that have fallen off from the cutting tool during processing are mixed in the waste liquid discharged from the processing device 4.

[0020] (Processing water purification means 8) The processing water purification means 8 includes a filter 22 that filters waste liquid to generate clean water, an ultraviolet irradiator 24 that destroys organic substances mixed in the clean water, a temperature controller 26, and an ion exchange resin 28 that generates pure water from the clean water.

[0021] (Filter 22) The filter 22 captures processing chips, abrasive grains, etc. mixed in the waste liquid and generates clean water from the waste liquid. The filter 22 is arranged downstream of the centrifugal pump 10, and the waste liquid in the water storage tank 6 is sent to the filter 22 by the centrifugal pump 10.

[0022] (Ultraviolet irradiator 24) The ultraviolet irradiator 24 performs sterilization treatment of the clean water by irradiating the clean water generated by the filter 22 with ultraviolet rays. The ultraviolet irradiator 24 is arranged downstream of the filter 22, and the clean water generated by the filter 22 is sent to the ultraviolet irradiator 24.

[0023] (Temperature Controller 26) The temperature controller 26 cools or heats the fresh water by performing heat exchange between the fresh water passing through the temperature controller 26 and the refrigerant circulating through the temperature controller 26, thereby adjusting the temperature of the fresh water to a predetermined temperature. Although not shown, the configuration of the temperature controller 26 may be, for example, a configuration including a compressor that compresses the refrigerant, a condenser that condenses the refrigerant compressed by the compressor, and an evaporator that vaporizes the refrigerant condensed by the condenser. The temperature controller 26 of the present embodiment is disposed downstream of the ultraviolet irradiator 24, and the fresh water sterilized by the ultraviolet irradiator 24 is fed into the temperature controller 26.

[0024] (Ion Exchange Resin 28) The ion exchange resin 28 purifies pure water from fresh water by removing impurities from the fresh water through ion exchange. The ion exchange resin 28 of the present embodiment is disposed downstream of the temperature controller 26, and the fresh water adjusted to a predetermined temperature by the temperature controller 26 is fed into the ion exchange resin 28. Note that the ion exchange resin 28 may be disposed between the ultraviolet irradiator 24 and the temperature controller 26.

[0025] (Centrifugal Pump 10, Waste Liquid Supply Path 12) The centrifugal pump 10 is disposed between the water storage tank 6 and the filter 22 of the processed water purification means 8, and the waste liquid supply path 12 connects the water storage tank 6 and the filter 22. The centrifugal pump 10 has the ability to allow the pressure to send the waste liquid into the processed water purification means 8 and to allow the flow rate of the processed water sent out from the processed water purification means 8 to be the flow rate of the processed water used in the processing apparatus 4. That is, the centrifugal pump 10 can discharge the waste liquid at a pressure greater than the pressure loss from the discharge port of the centrifugal pump 10 to at least the outlet of the processed water purification means 8 (in this embodiment, the outlet of the ion exchange resin 28), and can discharge an amount of waste liquid exceeding the total flow rate of the processed water used in all the processing apparatuses 4.

[0026] As shown in FIG. 1, an inverter 10b is provided for a motor 10a that drives a centrifugal pump 10. The inverter 10b changes the frequency of the power supplied to the motor 10a within a predetermined range. As a result, the rotational speed of the motor 10a is changed, and the rotational speed of the centrifugal pump 10 is changed within the range of the allowable rotational speed (between the minimum rotational speed and the maximum rotational speed). Note that the inverter 10b is electrically connected to a control means 18 and is controlled by the control means 18.

[0027] Although not shown, the centrifugal pump 10 discharges waste liquid by rotating an impeller in a casing with a gap provided between the casing and the impeller. For this reason, even if foreign matters such as machining chips generated during machining and abrasive grains that have fallen off from a machining tool during machining are mixed in the waste liquid sent out by the centrifugal pump 10, the foreign matters will not be bitten into the gap between the casing and the impeller, so the damage to the centrifugal pump 10 caused by foreign matters is small. Therefore, as a pump for sending waste liquid from the water storage tank 6 to the processing water purification means 8, the centrifugal pump 10 is most preferable.

[0028] (Supply pump 14, processing water supply path 16) The supply pump 14 is arranged between the ion exchange resin 28 of the processing water purification means 8 and the processing apparatus 4, and the processing water supply path 16 connects the ion exchange resin 28 and the processing apparatus 4. The supply pump 14 has the ability to allow the pressure and flow rate of the processing water sent out from the processing water purification means 8 to be supplied to the processing apparatus 4. That is, the supply pump 14 can discharge the processing water at a pressure greater than the pressure loss from the discharge port of the supply pump 14 to the processing water injection ports of all the processing apparatuses 4, and can discharge an amount of processing water exceeding the total flow rate of the processing water used in all the processing apparatuses 4.

[0029] A motor 14a that drives a supply pump 14 is provided with an inverter 14b, similar to the motor 10a of the centrifugal pump 10. The inverter 14b changes the frequency of the power supplied to the motor 14a within a predetermined range. As a result, the rotational speed of the motor 14a is changed, and the rotational speed of the supply pump 14 is changed within the range of the allowable rotational speed (between the minimum rotational speed and the maximum rotational speed). Note that the inverter 14b is electrically connected to the control means 18 and is controlled by the control means 18.

[0030] Note that since the fluid delivered by the supply pump 14 is the processed water purified by the processed water purification means 8, a positive displacement pump such as a piston pump or a gear pump can be adopted as the supply pump 14.

[0031] (Control means 18) The control means 18 controls the operation of the processed water supply device 2. Specifically, the control means 18 adjusts the pressure and flow rate of the processed water supplied to the processing device 4 by controlling the rotational speeds of the centrifugal pump 10 and the supply pump 14. In addition, the control means 18 adjusts the temperature of the processed water supplied to the processing device 4 by controlling the operation of the temperature controller 26 of the processed water purification means 8. Such control means 18 can be composed of a computer having a processor and a memory.

[0032] (Return path 30) In the present embodiment, a return path 30 is provided that is connected to the processed water supply path 16 between the processed water purification means 8 and the supply pump 14 and returns excess processed water to the water storage tank 6. By providing the return path 30, it becomes possible to continuously operate the centrifugal pump 10 at a constant rotational speed, so that the load acting on the centrifugal pump 10 can be reduced as the centrifugal pump 10 starts and stops. Note that an on-off valve (not shown) that is opened and closed by the control means 18 may be provided in the return path 30.

[0033] (Fine filter 32) In this embodiment, the precision filter 32 is disposed after the supply pump 14. In the ion exchange resin 28 of the processed water purification means 8, fine substances such as resin chips of the ion exchange resin 28 may be mixed into the purified water purified by ion exchange. Therefore, by disposing the precision filter 32 downstream of the supply pump 14, it is preferable to capture fine substances such as resin chips of the ion exchange resin 28.

[0034] (Operation of the Processed Water Supply Device 2) Next, the operation of the processed water supply device 2 described above will be explained.

[0035] When the required processing is performed by the processing device 4, an instruction to start operation is input to the control means 18 of the processed water supply device 2. Then, the control means 18 circulates the processed water between the processed water supply device 2 and the processing device 4 by operating the centrifugal pump 10 and the supply pump 14. That is, the waste liquid in the water storage tank 6 is sent by the centrifugal pump 10 to the processed water purification means 8, and after the waste liquid is purified into processed water and the temperature of the processed water is adjusted to a predetermined temperature in the processed water purification means 8, the processed water is supplied to the processing device 4 by the supply pump 14. Then, the waste liquid of the processed water used in the processing device 4 is returned to the water storage tank 6 via the waste liquid discharge path 20.

[0036] The control means 18 adjusts the rotation speed of the centrifugal pump 10 and the rotation speed of the supply pump 14 so that the flow rate Q1 of the processed water sent out from the processed water purification means 8 is the same as the flow rate Q2 of the processed water used in the processing device 4, or Q1 is slightly higher than Q2 (Q1≥Q2). At this time, the control means 18 discharges the waste liquid from the centrifugal pump 10 at a pressure higher than the pressure loss P1 from the discharge port of the centrifugal pump 10 to the outlet of the processed water purification means 8, and discharges the processed water from the supply pump 14 at a pressure higher than the pressure loss P2 from the discharge port of the supply pump 14 to the processed water injection ports of all the processing devices 4. Thereby, the processed water circulates between the processed water supply device 2 and the processing device 4, and the processed water with the required pressure can be used in the processing device 4.

[0037] During the operation of the processing water supply device 2, the amount of processing water used in the processing device 4 may decrease due to a decrease in the number of operating processing devices 4. In this case, the flow rate Q1 of the processing water sent out from the processing water purification means 8 may greatly exceed the flow rate Q2 of the processing water used in the processing device 4 (Q1 >> Q2). At this time, most of the processing water generated by the processing water purification means 8 will not be used in the processing device 4 and will return to the water storage tank 6 through the return path 30. Therefore, when the flow rate Q1 of the processing water sent out from the processing water purification means 8 greatly exceeds the flow rate Q2 of the processing water used in the processing device 4 (for example, when Q1 becomes 2 times or more or 3 times or more of Q2), the control means 18 reduces the rotational speed of the centrifugal pump 10. Thereby, the flow rate Q1 of the processing water sent out from the processing water purification means 8 is adjusted to be appropriate. That is, it is adjusted so that Q1 and Q2 are the same or Q1 slightly exceeds Q2 (Q1 ≧ Q2). As a result, an increase in power consumption can be suppressed.

[0038] As described above, in the processing water supply device 2 of the present embodiment, it includes a water storage tank 6 for storing the waste liquid used in the processing device 4, a processing water purification means 8 for purifying the waste liquid in the water storage tank 6 into processing water, a waste liquid supply path 12 provided with a centrifugal pump 10 for sending the waste liquid stored in the water storage tank 6 to the processing water purification means 8, a processing water supply path 16 provided with a supply pump 14 for supplying the processing water sent out from the processing water purification means 8 to the processing device 4, and a control means 18. The centrifugal pump 10 has the ability to allow the pressure for sending the waste liquid into the processing water purification means 8 and the flow rate of the processing water sent out from the processing water purification means 8 to allow the flow rate of the processing water used in the processing device 4. The supply pump 14 has the ability to allow the pressure and flow rate for supplying the processing water sent out from the processing water purification means 8 to the processing device 4. Therefore, a pure water facility is not required and it is economical.

[0039] In this embodiment, as described above, since the centrifugal pump 10 and the supply pump 14 are provided, as the centrifugal pump 10, an inexpensive small-capacity pump that allows the pressure loss P1 can be used. On the other hand, unlike this embodiment, when the waste liquid is sucked from the water storage tank 6 by one centrifugal pump and the processing water is supplied to the processing device 4 (when the supply pump 14 is not present), as the centrifugal pump, a large-capacity and expensive pump that allows the total value (P1 + P2) of the pressure losses P1 and P2 must be used. Therefore, in this embodiment, cost reduction can be achieved as compared with the case where the processing water is supplied to the processing device 4 by one centrifugal pump. Further, in this embodiment, the discharge pressure of the centrifugal pump 10 can be small (P1 is sufficient) as compared with the pressure (P1 + P2) when the processing water is supplied to the processing device 4 by one centrifugal pump. Therefore, the pressure acting on the processing water purification means 8 can be reduced, and the deterioration of the processing water purification means 8 can be delayed. Therefore, according to this embodiment, cost reduction and long life can be achieved.

Explanation of Signs

[0040] 2: Processing water supply device 4: Processing device 6: Water storage tank 8: Processing water purification means 10: Centrifugal pump 12: Waste liquid supply path 14: Supply pump 16: Processing water supply path 18: Control means 22: Filter 24: Ultraviolet irradiator 26: Temperature controller 28: Ion exchange resin

Claims

1. A processing water supply device for supplying processing water to a processing device, comprising: a water storage tank for storing waste liquid used in the processing device; processing water purification means for purifying the waste liquid in the water storage tank into processing water; a waste liquid supply path provided with a centrifugal pump for sending the waste liquid stored in the water storage tank into the processing water purification means; a processing water supply path provided with a supply pump for supplying the processing water sent out from the processing water purification means to the processing device; control means; and the centrifugal pump has the ability to allow the pressure for sending the waste liquid into the processing water purification means and to allow the flow rate of the processing water sent out from the processing water purification means to be the same as the flow rate of the processing water used in the processing device; the supply pump is a processing water supply device having the ability to allow the pressure and flow rate of the processing water sent out from the processing water purification means to be supplied to the processing device.

2. The processing water supply device according to claim 1, wherein a return path for returning excess processing water to the water storage tank is provided in the processing water supply path between the processing water purification means and the supply pump.

3. The processing water supply device according to claim 1, wherein the supply pump supplies processing water to two or more processing devices.

4. The processing water purification means according to claim 1, comprising a filter for filtering waste liquid to generate clean water, an ultraviolet irradiator for destroying organic substances mixed in the clean water, a temperature controller, and an ion exchange resin for generating pure water from the clean water.

5. The processing water supply device according to claim 4, wherein a precision filter is provided after the supply pump.

6. The processing water supply device according to claim 1 or 2, wherein when the flow rate of the processing water sent out from the processing water purification means exceeds the flow rate of the processing water used in the processing device, the control means reduces the rotational speed of the centrifugal pump to appropriately adjust the flow rate of the processing water.

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