Processing fluid supply method, processing fluid supply device, and processing device equipped therewith

Abstract

We propose a novel technology for supplying processing fluid using a waste liquid treatment device that circulates and utilizes the processing fluid. [Solution] A method for supplying a processing fluid to a processing apparatus by purifying waste processing fluid recovered from the processing apparatus and supplying the purified fluid to the processing apparatus as processing fluid, wherein a circulation path is provided which includes a processing fluid storage tank, at least one pump for discharging the processing fluid from the processing fluid storage tank, and at least one flow meter for measuring the flow rate of the discharged processing fluid, and the output of the pump is adjusted according to the measurement value of the flow meter to supply a predetermined flow rate of processing fluid to the processing apparatus.

Description

Technical Field

[0001] The present invention relates to a method for supplying a machining fluid when machining or grinding a workpiece.

Background Art

[0002] Conventionally, for example, as disclosed in Patent Document 1, when machining a semiconductor wafer as a workpiece, it is known to supply a machining fluid (cutting water) to a cutting blade for cooling. Patent Document 1 discloses a waste liquid treatment device that recovers and purifies the machining fluid cooled by the cutting blade as machining waste liquid, circulates it with a pump, and reuses it. In particular, in view of the fact that the circulating machining fluid gradually decreases due to evaporation or the like, replenishment is performed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional waste liquid treatment device, in order to stably supply a sufficient amount of machining fluid, the pump has always been driven at a constant high output to supply as much machining fluid as possible. For example, when the maximum supply amount of the waste liquid treatment device is designed to be 25 L / min, the pump is driven at a constant output so that the machining fluid can always be supplied at the maximum supply amount.

[0005] For this reason, there is a possibility that a situation of continuously supplying an excessive amount of machining fluid may occur, and there is a risk of continuously wasting power.

[0006] In view of the above problems, the present invention relates to a machining fluid supply method using a waste liquid treatment device that circulates and uses the machining fluid, and proposes a novel technique. [Means for solving the problem]

[0007] The problems that this invention aims to solve are as described above, and the means for solving these problems will now be explained.

[0008] According to one aspect of the present invention, there is a method for purifying waste liquid of processing fluid recovered from a processing apparatus and supplying the purified liquid to the processing apparatus as processing fluid, wherein a circulation path is provided which includes a processing fluid storage tank, at least one pump for discharging the processing fluid from the processing fluid storage tank, and at least one flow meter for measuring the flow rate of the discharged processing fluid, and the output of the pump is adjusted according to the measurement value of the flow meter to supply processing fluid at a predetermined flow rate to the processing apparatus.

[0009] Furthermore, according to one aspect of the present invention, the processing fluid supply device has a control unit, which measures the flow rate of the processing fluid per unit time measured by the flow meter and controls the output of the pump so that the flow rate matches a preset target value.

[0010] Furthermore, according to one aspect of the present invention, there is a processing fluid supply device having a circulation path for purifying waste processing fluid recovered from a processing device and supplying the purified liquid to the processing device as processing fluid, wherein the circulation path is provided with a processing fluid storage tank, at least one pump for discharging the processing fluid from the processing fluid storage tank, and at least one flow meter for measuring the flow rate of the discharged processing fluid, and the output of the pump is adjusted according to the measurement value of the flow meter so that a predetermined flow rate of processing fluid can be supplied to the processing device.

[0011] Furthermore, according to one aspect of the present invention, the processing fluid supply device has a control unit, which measures the flow rate of the processing fluid per unit time measured by the flow meter and controls the output of the pump so that the flow rate matches a preset target value.

[0012] Furthermore, according to one aspect of the present invention, there is a processing apparatus having a processing fluid supply device and a processing unit, wherein the processing fluid used in the processing unit is supplied from the processing fluid supply device, and the processing fluid used in the processing unit and discarded is purified and reused.

[0013] Furthermore, according to one aspect of the present invention, the processing unit is a cutting unit that dices a semiconductor wafer by cutting it with a cutting blade, or a grinding unit that thins a semiconductor wafer by grinding it with a grinding wheel. [Effects of the Invention]

[0014] The present invention provides the following effects: In other words, according to one aspect of the present invention, it becomes possible to operate the pump at the output necessary to supply the required flow rate of processing fluid to the processing device, eliminating the need to operate the pump at unnecessarily high output and avoiding unnecessary power consumption. [Brief explanation of the drawing]

[0015] [Figure 1] A diagram illustrating a cutting machine, which is an example of a processing device. [Figure 2] A diagram illustrating an example of a cutting unit. [Figure 3] A diagram illustrating an example configuration of a processing fluid supply device. [Figure 4] A diagram illustrating the relationship between the output of the motor driving the pump and the flow rate. [Figure 5] A diagram illustrating the configuration of Example 2 of the processing fluid supply device. [Figure 6] A diagram illustrating the configuration of Example 3 of the processing fluid supply device. [Figure 7] This diagram illustrates the relationship between the output of the motor driving the pump and the pressure in Example 3. [Figure 8] A diagram illustrating the configuration of Example 4 of the processing fluid supply device. [Figure 9]A diagram for explaining the relationship between the output of a motor driving a pump and pressure with respect to Example 4.

Embodiments for Carrying out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a cutting device 2 which is an example of a processing device in which the present invention is implemented. The cutting device 2 has a base 4, and a holding table 8 which can reciprocate in the X-axis direction by a cutting feed mechanism (X-axis movement mechanism) not shown is disposed on the base 4.

[0017] On the upper surface of the base 4, there are provided a cassette placement portion 5a for placing a cassette 5 for accommodating a wafer W (semiconductor wafer) which is a workpiece, and a cleaning unit 6 for cleaning the workpiece after cutting. The wafer W is fixed to a frame F via a tape T, is carried from the cassette 5 onto the holding table 8 by a transfer device, is cut by a cutting unit 34 (processing unit), is then transferred to the cleaning unit 6 for cleaning, and is carried out to the cassette 5 after cleaning.

[0018] A cleaning liquid is supplied to the cleaning unit 6 from a processing liquid supply device 70. The cleaning liquid which has become waste liquid after cleaning is recovered and returned to the processing liquid supply device 70, and after being purified by the processing liquid supply device 70, it is used as a cleaning liquid again. Note that the cleaning liquid may be supplied to the cleaning unit 6 from a system different from the processing liquid supply device 70, and the processing liquid may be purified in a system different from the system of the processing liquid supply device 70.

[0019] A plurality of clamps 9 and a water cover 11 are disposed around the holding table 8, and a bellows 12 for protecting the cutting feed mechanism disposed below is connected between this water cover 11 and the base 4.

[0020] A gate-shaped column 14 is erected on the base 4. On the side of the column 14 are a pair of guide rails 15 extending in the Y-axis direction, a Y-axis movement mechanism 17 consisting of a ball screw 16a and a pulse motor 16b, and a Y-axis movement block 18. The Y-axis movement block 18 moves in the Y-axis direction along the guide rails 15 by the drive of the Y-axis movement mechanism 17.

[0021] The Y-axis movement block 18 is provided with a pair of guide rails 19 extending in the Z-axis direction, a Z-axis movement mechanism 32 consisting of a ball screw 31a and a pulse motor 31b, and a Z-axis movement block 30. The Z-axis movement block 30 moves in the Z-axis direction along the guide rails 19 by the drive of the Z-axis movement mechanism 32.

[0022] A cutting unit 34 is attached to the Z-axis movement block 30. A spindle (not shown) is rotatably housed in the spindle housing 36 of the cutting unit 34, and a cutting blade 38 is mounted on the tip of the spindle. Approximately the upper half of the cutting blade 38 is covered by a blade cover (wheel cover) 40. An imaging unit 7 is located near the cutting unit 34.

[0023] Figure 2 illustrates the configuration of the cutting unit 34, which comprises a cutting blade 38 and a blade cover 40, with the cutting edge of the cutting blade 38 protruding downwards. The blade cover 40 is provided with blade cooler nozzles 41a and 41b that supply a processing fluid (cutting fluid) such as pure water to the lower part of the cutting blade 38, and a shower nozzle 46 that supplies a processing fluid (cutting fluid) to the outer circumference of the cutting blade 38.

[0024] As shown in Figure 2, the cutting blade 38 is, for example, a hub-type blade in which a cutting edge 38b is formed by electroplating on a base (hub base) 38a made of aluminum, or a cutting blade in which there is no base and the cutting edge is fixed with a flange.

[0025] Figure 2 shows that the lower end of the shower nozzle block 54 is provided with a cooling liquid nozzle 60a that is directed away from the cutting blade 38 and sprays a processing fluid (cooling liquid) to cool the wafer, which is the workpiece. The processing fluid (cooling liquid) is intended to cool the wafer and suppress the rise in ambient temperature, and the same processing fluid (cutting fluid) supplied from the blade cooler nozzles 41a, 41b and the shower nozzle 46 can be used.

[0026] The processing fluids discharged from the blade cooler nozzles 41a, 41b, shower nozzle 46, and coolant nozzle 60a shown in Figure 2, and the cleaning fluid used in the cleaning unit 6 shown in Figure 1, can each be supplied from the processing fluid supply device 70. The processing fluid supply device 70 can be configured to have different components for the processing fluids and cleaning fluids supplied to each part by providing multiple purification treatment systems, or it can be configured to have the same components for the processing fluids and cleaning fluids supplied to each part by providing a single purification treatment system. [Examples]

[0027] The following describes embodiments of the processing fluid supply device 70 using examples. Figure 3 is a block diagram showing the configuration of the processing fluid supply device 70. The processing fluid supply device 70 comprises a waste liquid tank 71 for recovering and temporarily storing waste liquid from the processing device 2, a filtration unit 72 for filtering the waste liquid taken in from the waste liquid tank 71, a processing fluid storage tank 73 (clean water tank) for temporarily storing the clean water filtered by the filtration unit 72, and a precision filter 74 for removing foreign matter from the liquid taken in from the processing fluid storage tank 73 and supplying it to the processing device 2.

[0028] The processing fluid supply device 70 includes a first pump 81 for pumping liquid from the waste liquid tank 71 to the filtration unit 72, and a second pump 82 for pumping liquid from the processing fluid storage tank 73 to the precision filter 74.

[0029] The processing fluid supply device 70 has a control unit 78 for controlling the outputs of the first pump 81 and the second pump 82. The control unit 78 has a control unit 78a and a storage unit 78b, and the control unit 78a executes a program that has been stored in the storage unit 78b in advance to control the outputs of the first pump 81 and the second pump 82, respectively. Alternatively, the first pump 81 may be omitted and the device may have only the second pump 82 by configuring the device so that liquid flows into the processing fluid storage tank 73 without using the first pump 81.

[0030] A flow meter 95 is provided in the supply path 91, which passes through the precision filter 74 and leads to the processing device 2, for measuring the flow rate of the processing fluid passing through the supply path 91 in real time. The control unit 78 measures the flow rate R2 of the processing fluid per unit time measured by the flow meter 95 and controls the output of the first pump 81 and / or the second pump 82 according to the flow rate R2.

[0031] More specifically, the memory unit 78b of the control unit 78 stores a target value M for the flow rate to pass through the supply path 91, and the control unit 78a controls the output of the first pump 81 and / or the second pump 82 so that the flow rate R2 matches the target value M by executing a program (feedback control).

[0032] The processing fluid supply device 70 includes inverters 81a and 82a that control the outputs of the first pump 81 and the second pump 82 to change them to predetermined values, and the control unit 78a controls the inverters 81a and 82a, thereby controlling the outputs of the first pump 81 and the second pump 82 by inverter control.

[0033] Figure 4 illustrates an example of the relationship between the output ratio (ratio to maximum output) of the motor speed of the second pump 82 (Figure 3) controlled by inverter and the flow rate R2 of the processing fluid per unit time passing through the supply path 91. This shows that the flow rate R2 can be controlled by adjusting the output of the second pump 82 (Figure 3). For example, when operating with a target value M of 15 L / min (liters / minute), the second pump (Figure 3) is controlled to operate at approximately 60% output.

[0034] As shown in Figure 3, the first pump 81 may measure the flow rate R1 into the filtration unit 72 using a flow meter (not shown) and control the flow rate R1 with the output of the first pump 81, while the flow rate R2 may be controlled by the output of the second pump 82. In this case, the relationship between the output and flow rate of the first pump 81 can also be controlled in the same way as shown in Figure 4. Furthermore, the first pump 81 may, for example, measure the remaining amount in the processing fluid storage tank 73 in real time and be controlled so that the remaining amount does not fall below a predetermined amount, thereby ensuring a stable supply of processing fluid from the storage tank 73.

[0035] As described above, the present invention provides a processing fluid supply device having a circulation path for purifying waste processing fluid recovered from a processing device and supplying the purified liquid to the processing device as processing fluid. The circulation path includes a processing fluid storage tank, at least one pump for discharging the processing fluid from the processing fluid storage tank, and at least one flow meter for measuring the flow rate of the discharged processing fluid. The output of the pump is adjusted according to the measurement value of the flow meter, enabling the supply of processing fluid at a predetermined flow rate to the processing device.

[0036] This allows the pump to operate at the output necessary to supply the required flow rate of processing fluid to the processing equipment, eliminating the need to operate the pump at unnecessarily high output and avoiding wasted power consumption.

[0037] Furthermore, in the configuration shown in Figure 3, by providing multiple second pumps 82 and precision filters 74, multiple paths for supplying processing fluid from the processing fluid storage tank 73 to the processing fluid supply device 70 may be configured, and processing fluid may be supplied from each path to each supply point of the processing device, such as the blade cooler nozzles 41a, 41b, shower nozzle 46, and cooling fluid nozzle 60a shown in Figure 2.

[0038] According to this, the required flow rate of processing fluid can be supplied to each supply point of the processing equipment, and unnecessary power consumption can be avoided by controlling the pumps in each path.

[0039] Furthermore, in the above embodiments, a cutting apparatus having a cutting unit (processing unit) that cuts and dices a semiconductor wafer using a cutting blade was used as an example of a processing apparatus. However, the present invention can be broadly applied to other processing apparatuses, such as a grinding apparatus having a grinding unit (processing unit) that thins a semiconductor wafer using a grinding wheel, where a processing fluid is supplied during processing and waste fluid needs to be collected and reused.

[0040] In the above example, only the output ratio of the motor speed of the second pump 82 was adjusted, but the output ratio of the motor speed of the first pump 81 may also be adjusted in the same way as needed. [Examples]

[0041] Figure 5 shows another embodiment of the processing fluid supply device. In the configuration shown in Figure 5, compared to the configuration of Embodiment 1, a path 96 is provided downstream of the flow meter 95 in the supply path 91 that passes through the precision filter 74 and leads to the processing apparatus 2, to return the excess processing fluid to the processing fluid storage tank 73. For example, a control valve (not shown) controlled by a control unit 78 may be provided in this path 96, and the control valve may be opened and closed according to the measurement value of the flow meter 95. [Examples]

[0042] Figure 6 shows another embodiment of the processing fluid supply device. In this embodiment 3, compared to embodiment 2, a pressure gauge 97 is provided downstream of the flow meter 95 in the supply path 91 that passes through the precision filter 74 and leads to the processing device 2, to measure the pressure of the processing fluid.

[0043] For example, when processing fluid is supplied from the processing fluid supply device 70 to the cutting device 2, the pressure of the processing fluid in the cutting device 2 is preferably 0.2 MPa or more and 0.3 MPa or less. Also, for example, when processing fluid is supplied from the processing fluid supply device 70 to a grinding device (grinder) instead of the cutting device 2, the pressure of the processing fluid in the grinding device is preferably 0.3 MPa or more and 0.4 MPa or less.

[0044] Thus, the pressure of the processing fluid that should be supplied may differ depending on the type of processing equipment (cutting equipment or grinding equipment) to which the processing fluid is supplied, or even within the same type of processing equipment, depending on the specifications of each piece of equipment.

[0045] In view of the above, the control unit 78 measures the pressure V of the processing fluid measured by the pressure gauge 97 and controls the output of the first pump 81 and / or the second pump 82 according to the pressure V.

[0046] Figure 7 illustrates an example of the relationship between the output ratio (ratio to maximum output) of the motor speed of the second pump 82 (Figure 6) controlled by inverter and the pressure V of the processing fluid passing through the supply path 91. It shows that the pressure V can be controlled by adjusting the output of the second pump 82 (Figure 6). For example, when operating with a target pressure V of 0.2 MPa (megapascals), the second pump (Figure 6) is controlled to operate at approximately 60% output.

[0047] For example, operation at approximately 60% output could be designated as an energy-saving mode, and a selection button for selecting this mode could be displayed on the operation screen (e.g., touch panel) of the processing fluid supply device so that the operator can choose it at will. Alternatively, the operation screen could prompt the operator to select the energy-saving mode as a recommended setting for the operating mode. In this case, for example, the processing device could transmit information about the pressure V necessary or suitable for the processing device, as well as information about the operating mode, to the processing fluid supply device via communication.

[0048] As described above, it becomes possible to operate the pumps at the output necessary to achieve the pressure required for each processing device, eliminating the need to operate the pumps at unnecessarily high output and avoiding wasted power consumption. In the above example, only the output ratio of the motor speed of the second pump 82 was adjusted, but the output ratio of the motor speed of the first pump 81 may also be adjusted in the same way as needed. [Examples]

[0049] Figure 8 shows another embodiment using a processing fluid supply device. This embodiment 4 is an example in which processing fluid is supplied from one processing fluid supply device 70 to multiple processing devices 2A, 2B, and 2C (for example, three devices). The processing fluid sent from the supply path 91 is supplied to each processing device 2A, 2B, and 2C through branching paths, and the processing fluid used in each processing device 2A, 2B, and 2C is recovered to the processing fluid supply device 70.

[0050] Each processing device 2A, 2B, and 2C is equipped with control valves 2a, 2b, and 2c, respectively, for stopping and starting the supply of coolant. The open / closed state of the control valves 2a, 2b, and 2c is recognized by the control unit 78 of the processing fluid supply device 70 via communication. The operator can set the open / closed state of the control valves 2a, 2b, and 2c using the operation screen of each processing device 2A, 2B, and 2C.

[0051] The control unit 78 of the processing fluid supply device 70 measures the processing fluid pressure V measured by the pressure gauge 97 and controls the output of the first pump 81 and / or the second pump 82 according to the pressure V.

[0052] Figure 9 illustrates an example of the relationship between the output ratio (ratio to maximum output) of the motor speed of the second pump 82 (Figure 8) controlled by an inverter and the pressure V of the processing fluid passing through the supply path 91. In Figure 9, when processing fluid is supplied to three processing devices 2A, 2B, and 2C (Figure 8), the output of the second pump 82 (Figure 8) is 100%, and the pressure V measured by the pressure gauge 97 is 0.2 MPa (megapascals). This pressure V of 0.2 MPa is a preferred pressure for the processing fluid supplied to each processing device 2A, 2B, and 2C (Figure 8).

[0053] As described above, when processing fluid is supplied to the three processing devices 2A, 2B, and 2C (Figure 8), the control unit 78 (Figure 8) operates the second pump 82 (Figure 8) at 100% output, as shown in Figure 9. In this case, the control unit 78 (Figure 8) recognizes that the control valves 2a, 2b, and 2c (Figure 8) are open and that processing fluid is being supplied to the three processing devices.

[0054] Now, let's assume that the operator's actions stop the supply of processing fluid to two processing devices, resulting in a situation where processing fluid is supplied to only one processing device. The control unit 78 (Figure 8) recognizes the number of open control valves 2a, 2b, and 2c (Figure 8) and controls the second pump 82 (Figure 8) to operate at, for example, approximately 60% of its output based on that number. In this case, the pressure V measured by the pressure gauge 97 is maintained at 0.2 MPa (megapascals).

[0055] As described above, it becomes possible to operate the pumps at the required output according to the number of processing devices, eliminating the need to operate the pumps at unnecessarily high output and avoiding wasted power consumption.

[0056] For example, an energy-saving mode could be set to operate at approximately 60% of the output when supplying processing fluid to a single processing device, and a selection button could be displayed on the operation screen (e.g., touch panel) of the processing fluid supply device so that the operator can arbitrarily select this mode. Alternatively, the operation screen could prompt the operator to select the energy-saving mode as a recommended setting for the operating mode. In this case, for example, the processing device could transmit information about the pressure V necessary or suitable for the processing device, as well as information about the operating mode, to the processing fluid supply device via communication.

[0057] Furthermore, if the supply of processing fluid to two processing devices is stopped and processing fluid is supplied to only one processing device, operating the pump at 100% without reducing its output would cause the pressure V of the processing fluid to rise sharply, potentially harming the processing device. However, this problem can be avoided by adjusting (reducing) the pump output to the target value (0.2 MPa in this embodiment). In the above example, only the output ratio of the motor speed of the second pump 82 was adjusted, but the output ratio of the motor speed of the first pump 81 may also be adjusted in the same way as needed. [Explanation of Symbols]

[0058] 2 Cutting equipment 4 bases 5 cassettes 5a Cassette mounting section 6. Washing Unit 7 Imaging Unit 8. Holding Table 9 clamps 11 Water Cover 34 Cutting Units 38 cutting blades 40 Blade Cover 41a Blade cooler nozzle 41b Blade Cooler Nozzle 46 Shower Nozzle 60a Coolant Nozzle 70 Processing fluid supply device 71 Waste liquid tank 72 Filtration Units 73 Processing fluid storage tank 74 Precision Filters 78 Control Unit 78a Control Unit 78b Storage section 81 Pump No. 1 81A Inverter 82 Pump No. 2 82A Inverter 91 Supply routes 95 Flow meter F Frame T Tape W wafer M Target value R1 flow rate R2 flow rate

Claims

1. A method for purifying waste liquid from processing fluid recovered from a processing apparatus and supplying the purified liquid to the processing apparatus as processing fluid, Using a circulation path that includes a processing fluid storage tank, at least one pump for discharging the processing fluid from the processing fluid storage tank, and at least one flow meter for measuring the flow rate of the discharged processing fluid, A method for supplying processing fluid, comprising adjusting the output of the pump according to the measurement value of the flow meter and supplying a predetermined flow rate of processing fluid to the processing device.

2. The processing fluid supply device has a control unit, The control unit is, The flow rate of the processing fluid per unit time, as measured by the flow meter, is measured. The output of the pump is controlled so that the flow rate matches a preset target value. The processing fluid supply method according to feature 1.

3. A processing fluid supply device having a circulation path for purifying waste liquid from processing fluid recovered from a processing device and supplying the purified liquid to the processing device as processing fluid, The circulation path is equipped with a processing fluid storage tank, at least one pump for dispensing the processing fluid from the processing fluid storage tank, and at least one flow meter for measuring the flow rate of the dispensed processing fluid. The output of the pump is adjusted according to the measurement value of the flow meter. A processing fluid supply device that can supply a predetermined flow rate of processing fluid to the processing device.

4. The processing fluid supply device has a control unit, The control unit is, The flow rate of the processing fluid per unit time, as measured by the flow meter, is measured. The output of the pump is controlled so that the flow rate matches a preset target value. The processing fluid supply device according to feature 3.

5. A processing fluid supply device according to claim 3 or claim 4, Processing unit and A processing apparatus having, The processing fluid used in the processing unit is supplied from the processing fluid supply device, A processing device that purifies and reuses the processing fluid that has been used and discarded in the processing unit.

6. The processing unit is, A cutting unit that cuts and dices semiconductor wafers using cutting blades. Or, This is a grinding unit that thins semiconductor wafers by grinding them with a grinding wheel. The processing apparatus according to claim 5, characterized in that

Images