Wastewater treatment device, processing device, and workpiece processing method

Abstract

To enable miniaturization and reduce the burden of maintenance. [Solution] The wastewater treatment device (1) removes processing scraps or processing scraps and water-soluble resins from processing wastewater (W) containing processing scraps and water-soluble resins discharged from a processing device (2) that processes a workpiece using processing water, using a hollow fiber membrane (12). The wastewater treatment device includes a tank (11) for storing processing wastewater, an air inlet (25) located at the top of the tank for introducing high-pressure air into the tank from a high-pressure air supply source (AS), a tank inlet (18) for introducing processing wastewater into the tank, a tank outlet (19) for discharging the processing wastewater from the tank, a case (13) housing the hollow fiber membrane, a case inlet (31) for introducing the processing wastewater discharged from the tank outlet into the case, a case outlet (33) for discharging permeate water that has passed through the hollow fiber membrane from the case, and a pumping unit that, after introducing processing wastewater into the tank, uses high-pressure air to pump the processing wastewater from the tank into the case.

Description

Technical Field

[0001] The present invention relates to a wastewater treatment device for treating processing wastewater discharged from a processing device, a processing device, and a method for processing a workpiece.

Background Art

[0002] Patent Document 1 discloses a processing method for forming a processing groove by irradiating a workpiece with a laser beam. In Patent Document 1, a water-soluble liquid resin is applied to the surface of the workpiece to form a protective film so that the melt (debris) of the workpiece does not adhere to the upper surface of the workpiece.

[0003] In Patent Document 1, after forming the protective film and then forming the processing groove by laser processing, water is sprayed onto the protective film to dissolve the protective film, and the protective film is removed together with the debris. Further, the protective film is also used as a mask of the device when the workpiece is plasma-dicing. Thus, since the water sprayed when removing the protective film contains a water-soluble liquid resin, a treatment for removing the liquid resin is performed in the waste liquid treatment facility.

[0004] Conventionally, in order to remove such a liquid resin, the device disclosed in Patent Document 2 is used. In Patent Document 2, the waste liquid is pumped from a tank by a pump and filtered through a hollow fiber membrane.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, Patent Document 2 has the problem that the device becomes large because a pump is used to pressurize the waste liquid into the hollow fiber membrane. In addition, if the pump is motor-driven, the mechanical parts that rotate due to the motor and the sealing parts that prevent liquid leakage come into contact with the waste liquid, which increases the amount of maintenance work required for these parts.

[0007] This invention has been made in view of the above, and one of its objectives is to provide a waste liquid treatment device, a processing device, and a workpiece processing method that can be miniaturized and reduce the burden of maintenance. [Means for solving the problem]

[0008] A wastewater treatment apparatus according to one aspect of the present invention is a wastewater treatment apparatus that uses a hollow fiber membrane to remove processing debris or the processing debris and water-soluble resin from processing wastewater containing processing debris discharged from a processing apparatus that processes a workpiece using processing water, or from processing wastewater containing at least water-soluble resin discharged from a processing apparatus that processes a workpiece coated with a water-soluble resin, comprising: a tank for storing the processing wastewater; an air inlet located at the top of the tank for introducing high-pressure air into the tank from a high-pressure air supply source; a tank inlet for introducing the processing wastewater into the tank; a tank outlet for discharging the processing wastewater from the tank; a case housing the hollow fiber membrane; a case inlet for introducing the processing wastewater discharged from the tank outlet into the case; a case outlet for discharging permeate water that has passed through the hollow fiber membrane from the case; and a pressurizing unit that, after introducing the processing wastewater into the tank, introduces high-pressure air to pressurize the processing wastewater in the tank into the case using the high-pressure air.

[0009] A processing apparatus according to one aspect of the present invention includes a chuck table for holding a workpiece, a processing unit for processing the workpiece, and the wastewater treatment apparatus.

[0010] A workpiece processing method according to one aspect of the present invention is a workpiece processing method using the wastewater treatment device described above, comprising: a protective film forming step of spreading the water-soluble resin on the surface of the workpiece to form a protective film; a holding step of holding the workpiece with a chuck table in a state in which the protective film is exposed; a processing step of processing the workpiece from the side of the protective film; and a protective film removal step of removing the protective film after the processing step using water treated by the wastewater treatment device.

[0011] Furthermore, a workpiece processing method according to one aspect of the present invention is a workpiece processing method using the above-mentioned wastewater treatment device, comprising: a holding step of holding the workpiece with a chuck table; and a processing step of processing the workpiece with a processing unit while supplying the water treated by the wastewater treatment device to the workpiece as processing water. [Effects of the Invention]

[0012] According to the present invention, since the processing wastewater is pumped to the hollow fiber membrane using high-pressure air from a high-pressure air supply source, the installation of a pump is unnecessary, resulting in space savings and miniaturization. Furthermore, the processing wastewater can be pumped without any mechanical parts rotating by a motor coming into contact with it, reducing maintenance man-hours such as the replacement of mechanical parts and sealing parts that prevent liquid leakage. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1A is a schematic diagram of the wastewater treatment device according to the embodiment, showing the state in which wastewater is being stored in the tank, and Figure 1B shows the state in which wastewater is being treated. [Figure 2] This is an explanatory diagram showing an example of a workpiece processing method according to the embodiment, where Figure 2A is an explanatory diagram of the protective film formation process and Figure 2B is an explanatory diagram of the processing process. [Figure 3] This is an explanatory diagram showing an example of a workpiece processing method according to the embodiment, where Figure 3A is an explanatory diagram of the processing step and Figure 3B is an explanatory diagram of the protective film removal step. [Figure 4]This is an explanatory diagram showing another example of the workpiece processing method according to the embodiment, where Figure 4A is an explanatory diagram of the holding process and Figure 4B is an explanatory diagram of the processing process. [Modes for carrying out the invention]

[0014] The wastewater treatment apparatus according to the embodiment will be described below with reference to the attached drawings. Figure 1A is a schematic diagram of the wastewater treatment apparatus according to the embodiment.

[0015] As shown in Figure 1A, the wastewater treatment device 1 is a device that removes processing debris from processing wastewater W containing processing debris discharged from the processing device 2. The processing device 2 is not limited to any device that processes a workpiece (not shown) using processing water, and examples include cutting devices, grinding devices, polishing devices, cutting tools, laser processing devices, and plasma etching devices. For example, in grinding devices, polishing devices, cutting tools, and cutting devices, processing water is supplied while processing the workpiece. Then, processing debris generated during processing is discharged as processing wastewater W containing processing water. In laser processing devices and plasma dicing devices, a liquid water-soluble resin is applied to the surface of the workpiece to form a protective film, and processing debris, which becomes debris, adheres to the protective film when processing grooves are formed by laser processing. Then, after the processing grooves are formed, processing water (washing water) is sprayed onto the protective film, and the water-soluble resin (protective film) dissolved in the processing water is discharged as processing wastewater W containing processing water, or the dissolved water-soluble resin and processing debris are discharged as processing wastewater W containing processing water. The wastewater treatment device 1 removes water-soluble resins and processing debris contained in such processing wastewater W. A method for processing a workpiece using the wastewater treatment device 1 and a part of the processing apparatus 2 exemplified above will be described later.

[0016] The wastewater treatment device 1 comprises a tank 11 for storing processing wastewater W, a case 13 containing a hollow fiber membrane 12, and a control unit 16.

[0017] The tank 11 is provided with a tank inlet 18 for putting the processed waste water W into the tank 11 and a tank outlet 19 for discharging the processed waste water W in the tank 11. The downstream end of a waste water pipe 21 through which the processed waste water W discharged from the processing device 2 flows is connected to the tank inlet 18, and the tank 11 and the processing device 2 are connected and communicated with each other through the waste water pipe 21. A waste water valve 22 is arranged on the waste water pipe 21. When the waste water valve 22 is opened, the processed waste water W discharged from the processing device 2 into the waste water pipe 21 flows into the tank 11 through the tank inlet 18, and when the waste water valve 22 is closed, the inflow of the processed waste water W into the tank 11 is restricted.

[0018] The tank outlet 19 is provided on the bottom wall of the tank 11 or the side wall near the bottom wall. The upstream end of a discharge pipe 23 through which the processed waste water W stored in the tank 11 is sent out is connected to the tank outlet 19.

[0019] Furthermore, the tank 11 is provided with an air inlet 25 for putting high-pressure air into the tank 11 and a pressure relief port 26 for discharging the air in the tank 11. The air inlet 25 and the pressure relief port 26 are arranged on the top wall of the upper part of the tank 11. One end of a supply pipe 27 is connected to the air inlet 25, and the tank 11 and a high-pressure air supply source AS are connected through the supply pipe 27. An air valve 28 is arranged on the supply pipe 27. By opening and closing the air valve 28, the communication state and the non-communication state between the tank 11 and the high-pressure air supply source AS can be switched.

[0020] The high-pressure air supply source AS can be exemplified as a large compressor (not shown) that supplies high-pressure air to a plurality of various devices in a factory or a facility. The high-pressure air supplied from such a compressor has various utilization modes according to various devices.

[0021] A pressure relief valve 30 is arranged on the pressure relief port 26. By opening and closing the pressure relief valve 30, the communication state and the non-communication state between the inside and the outside of the tank 11 can be switched. Therefore, when the pressure relief valve 30 is opened, the air in the tank 11 is discharged through the pressure relief port 26 and the air pressure in the tank 11 becomes atmospheric pressure, and when the pressure relief valve 30 and the waste water valve 22 are closed, the airtightness in the tank 11 is maintained.

[0022] Case 13 is provided, for example, in a bottomed cylindrical shape with both ends closed, and a plurality of hollow fiber membranes 12 forming a cylindrical shape are accommodated in the inner space. The cylindrical hollow fiber membranes 12 are configured such that a large number of fine holes are formed on their side surfaces, and are bundled so that their longitudinal directions are parallel to the longitudinal direction (vertical direction) of Case 13 and their side surfaces contact each other, and are disposed in Case 13. When the processing wastewater W is flowed through the internal space serving as the primary side of the hollow fiber membrane 12, the processing waste and dissolved resin contained in the processing wastewater W are separated without being permeated, and the processing wastewater W is filtered to obtain filtered permeated water (filtered water) on the permeation side serving as the secondary side.

[0023] A case inlet 31 to which the downstream end of the discharge pipe 23 is connected is provided in Case 13. The case inlet 31 communicates with the primary side of the hollow fiber membrane 12, and the processing wastewater W flowing out from the tank outlet 19 through the case inlet 31 is introduced into Case 13. A discharge valve 32 is disposed in the discharge pipe 23 connected to the case inlet 31. When the discharge valve 32 is opened, the processing wastewater W in the tank 11 can be sent into Case 13 through the case inlet 31, and when the discharge valve 32 is closed, the sending of the processing wastewater W into Case 13 is restricted.

[0024] Further, a case outlet 33 is provided in Case 13, and a permeated water storage pipe 36 connected to the permeated water tank 35 is connected to the case outlet 33. The case outlet 33 communicates with the secondary side of the hollow fiber membrane 12, and the permeated water that has passed through the hollow fiber membrane 12 comes out of Case 13 through the case outlet 33.

[0025] The permeated water sent out from the case outlet 33 of Case 13 through the permeated water storage pipe 36 is stored in the permeated water tank 35. The permeated water stored in the permeated water tank 35 is sent (water supply) to the processing device 2 through the permeated water introduction pipe 38 by driving the water supply pump 37, and the permeated water is used (reused) as processing water in the processing device 2. Furthermore, if the processing water used in processing apparatus 2 is ultrapure water, the permeate should be sent to an ultrapure water generator that produces ultrapure water. Alternatively, if the permeate is not to be reused in processing apparatus 2, it may be sent to the wastewater treatment facility of the factory where processing apparatus 2 is installed.

[0026] The control unit 16 is configured to include a processor that performs various processes, as well as a memory that stores various parameters and programs. The memory stores programs that control, for example, the opening and closing of the wastewater valve 22, air valve 28, pressure relief valve 30 and discharge valve 32, and the driving of the water supply pump 37, as part of the control program.

[0027] Next, the wastewater treatment method in the wastewater treatment apparatus 1 will be explained with reference to Figure 1. Figure 1A shows the state in which the processing wastewater W is being stored in the tank 11, and Figure 1B shows the state in which the processing wastewater W is being treated by the hollow fiber membrane 12.

[0028] In the state shown in Figure 1A, the processing wastewater W discharged from the processing apparatus 2 is stored in the tank 11 of the wastewater treatment apparatus 1. At this time, the control unit 16 opens the wastewater valve 22 and the pressure relief valve 30, and closes the air valve 28 and the discharge valve 32.

[0029] When the wastewater valve 22 is opened, the processing wastewater W discharged from the processing apparatus 2 flows into the tank 11 through the wastewater pipe 21. When the pressure relief valve 30 is opened, the air pressure inside the tank 11 is maintained at atmospheric pressure even if the volume of processing wastewater W inside the tank 11 changes. When the air valve 28 is closed, the supply of high-pressure air from the high-pressure air supply source AS into the tank 11 is stopped. When the discharge valve 32 is closed, the discharge of processing wastewater W from the tank 11 to the case 13 is restricted.

[0030] As shown in Figure 1A, when the wastewater W in the tank 11 is filtered after being placed in the tank 11, as shown in Figure 1B, the wastewater valve 22 and the pressure relief valve 30 are closed and the air valve 28 and the discharge valve 32 are opened under the control of the control unit 16. Furthermore, depending on the inner diameter of the wastewater pipe 21 or the flow rate of the processed wastewater W, the wastewater pipe 21 can be used as a pressure relief port, making the pressure relief port 26 and pressure relief valve 30 unnecessary.

[0031] When the wastewater valve 22 is closed, the inflow of processing wastewater W from the processing device 2 to the tank 11 is restricted. When the wastewater valve 22 and the pressure relief valve 30 are closed, the airtightness inside the tank 11 is maintained. When the discharge valve 32 is opened, the discharge of processing wastewater W from the tank 11 to the case 13 is permitted.

[0032] When the air valve 28 is opened, high-pressure air is introduced into the tank 11 from the high-pressure air supply source AS. As a result, the pressure (air pressure) in the space above the liquid surface of the processing wastewater W in the tank 11 is increased by the high-pressure air, and the processing wastewater W in the tank 11 is subjected to the pressure (positive pressure) of the high-pressure air. As the processing wastewater W in the tank 11 is subjected to the pressure of the high-pressure air, the processing wastewater W is pumped from the tank 11 to the case 13 through the discharge pipe 23. In other words, the pressure pumped into case 13 can be varied depending on the surface area of ​​the processing wastewater W. Also, by releasing the pressure (positive pressure) in the space above the surface of the processing wastewater W in tank 11, the pressure (positive pressure) on case 13 can be released, thus shortening the time required to replace the hollow fiber membrane 12.

[0033] Here, the pressurized pumping section is configured with a control unit 16, a wastewater pipe 21, a wastewater valve 22, a supply pipe 27, an air valve 28, a discharge pipe 23, and a discharge valve 32. With this pressurized pumping section, the wastewater treatment device 1 uses high-pressure air from a high-pressure air supply source AS to pressurize the processing wastewater W in the tank 11 into the case 13.

[0034] The processing wastewater W, which is pumped into case 13, passes through the hollow fiber membrane 12 housed in case 13. At this time, the hollow fiber membrane 12 is used to filter the processing wastewater W, removing processing debris and water-soluble resins from the processing wastewater W. The permeate obtained after passing through the hollow fiber membrane 12 is sent from case 13 through the permeate storage pipe 36 to the permeate tank 35 and stored there. Then, the control unit 16 drives the water supply pump 37, and the permeate stored in the permeate tank 35 is supplied to the processing apparatus 2 as appropriate as water treated by the wastewater treatment device 1 and used as processing water.

[0035] According to the above embodiment, the high-pressure air supplied from the high-pressure air supply source AS into the tank 11 is controlled to pressurize the processing wastewater W into the case 13. This eliminates the need for devices such as electrically driven pumps to pressurize the processing wastewater W into the case 13 and the hollow fiber membrane 12, thereby enabling miniaturization of the wastewater treatment device 1 and reduction of its installation area. Moreover, the processing wastewater W can be pressurized without any mechanical parts rotated by a motor coming into contact with the processing wastewater W, reducing maintenance man-hours such as the replacement of mechanical parts and sealing parts that prevent liquid leakage.

[0036] Furthermore, the control unit 16 controls the valves 22, 28, 30, and 32, allowing for easy switching between sending the hollow fiber membrane 12 from the tank 11 to the case 13 containing it and stopping the sending. Additionally, the internal pressure of the case 13 can be easily adjusted to atmospheric pressure. Furthermore, the filtration of processing wastewater W using the hollow fiber membrane 12 may be performed using a cross-flow method in addition to the filtration method. In the case of the cross-flow method, a return pipe may be provided connecting the case 13 and the tank 11, and the processing wastewater W containing processing debris filtered by the hollow fiber membrane 12 may be returned to the tank 11 to extend the period during which filtration by the hollow fiber membrane 12 is possible. In the case of the filtration method, the hollow fiber membrane 12 may be backwashed when the processing wastewater W is not being pumped to extend the period during which filtration is possible.

[0037] Next, a workpiece processing method using the wastewater treatment device 1 described above will be explained with reference to Figures 2 to 4. Figures 2 and 3 show an example of a workpiece processing method according to the embodiment. In the workpiece processing method shown in Figures 2 and 3, the steps are carried out in the order of protective film formation, processing, and protective film removal. Note that the steps described below are merely examples and are not limited to this configuration.

[0038] Here, before the processing method for the workpiece 100 is carried out, tape T is attached to the back surface 102 of the workpiece 100, which is made up of a wafer, and the workpiece 100 is supported by an annular frame F via this tape T. Therefore, when supported by the frame F, the workpiece 100 is in a state where the surface 101 on which multiple devices 104 are formed between grid-like streets 103 is exposed upwards. In the following description, each process is carried out with the workpiece 100 supported by tape T and frame F, but each process may also be carried out without tape T and frame F. In addition, tape T may be made of different materials and functions depending on the processing or treatment in each process. The same applies to the workpiece processing method shown in Figure 4, which will be described later.

[0039] The processing apparatus 2 used for processing the workpiece 100 in Figure 2 comprises a protective film forming unit 210 (see Figure 2A), a laser processing unit 220 (see Figure 2B), a plasma etching unit 230 (see Figure 3A), and a protective film removal unit 240 (see Figure 3B).

[0040] [Protective film formation process] Figure 2A is an explanatory diagram of the protective film formation process. As shown in Figure 2A, in the protective film formation process, the workpiece 100 is held by suction on the holding table 211 of the protective film formation unit 210 via tape T. The protective film formation unit 210 is equipped with a resin supply nozzle 212 and an air nozzle 213 located above the holding table 211. A resin supply source 214 is connected to the resin supply nozzle 212, and a water-soluble resin, which is a liquid resin, is dripped onto the workpiece 100 from the resin supply nozzle 212. An air source 215 is connected to the air nozzle 213.

[0041] In the protective film formation process, water-soluble resin is dripped from the resin supply nozzle 212. When a pool of liquid forms in the center of the surface 101 of the workpiece 100, the supply of water-soluble resin is stopped, and the holding table 211 that holds the workpiece 100 is rotated. Due to the centrifugal force accompanying the rotation of the holding table 211, the water-soluble resin is spread over the surface 101 of the workpiece 100, covering the entire surface 101. Then, while the holding table 211 is rotating, air is blown from the air nozzle 213 onto the water-soluble resin that has spread over the surface 101 of the workpiece 100, drying the water-soluble resin and forming the protective film 120.

[0042] The protective film 120 prevents debris from adhering to the surface 101 of the workpiece 100, including the device 104, during the processing step. Examples of water-soluble resins include polyvinyl alcohol (PVA) and polyethylene glycol (PEG).

[0043] [Processing process] Figures 2B and 3A are explanatory diagrams of the machining process. As shown in Figure 2B, in the machining process, the workpiece 100 is held on the chuck table 221 of the laser machining unit 220 via a tape T. The laser machining unit 220 includes an X-axis movement mechanism 222 that moves the chuck table 221 in the X-axis direction (machining feed direction) and a Y-axis movement mechanism 223 that moves the chuck table 221 in the Y-axis direction (indexing feed direction). The laser machining unit 220 also includes a laser irradiation unit 224 located above the chuck table 221 that irradiates a laser beam LB. Each of the movement mechanisms 222 and 223 can be exemplified by using linear motion mechanisms such as air cylinders or ball screw type feed mechanisms.

[0044] In the processing step, the workpiece 100 is held by the chuck table 221 of the laser processing unit 220 with the protective film 120 exposed via the tape T. The laser irradiation unit 224 irradiates the street 103 of the workpiece 100 with a laser beam LB from the protective film 120 side and focuses it while driving the respective moving mechanisms 222 and 223. As the moving mechanisms 222 and 223 drive the laser irradiation unit 224 relative to the workpiece 100 in the direction of extension of the street 103, the laser beam LB is irradiated onto the workpiece 100 from the protective film 120 side.

[0045] The laser beam LB has a wavelength that is absorbed by the workpiece 100 and is adjusted to focus on the vicinity of the surface 101 of the workpiece 100. When the laser beam LB is irradiated onto the workpiece 100, ablation is performed on the protective film 120 and the surface 101 of the workpiece 100. As a result, the protective film 120 is removed in the portion of the workpiece 100 along the street 103, and a processed groove 105 is formed that exposes the street 103. In other words, the protective film 120 that remains without being removed forms a mask 121 that masks (covers) the surface of the device 104.

[0046] In the processing step, after a mask 121 is formed on the workpiece 100, the workpiece 100 is held by the chuck table 231 of the plasma etching unit 230 via the tape T, as shown in Figure 3A. The plasma etching unit 230 includes a chamber 232 that houses the chuck table 231, and a plasma supply unit 234 that supplies plasma-state gas through a supply passage 233 provided in the chamber 232.

[0047] In the processing step, the workpiece 100 is held on the chuck table 231 in the chamber 232, and then plasma etching is performed by supplying plasma-state gas from the plasma supply unit 234 to the workpiece 100. As a result, plasma etching is performed on the workpiece 100 from the mask 121 side in the unformed areas of the mask 121 in the street 103, and the workpiece 100 is divided along the street 103 to form device chips containing one device 104 each. During the processing step, processing debris scattered by the formation of processing grooves 105 by laser processing and plasma etching adheres to the mask 121 (protective film 120).

[0048] In the above description, etching was performed using a so-called remote plasma method, in which plasma-state gas is introduced into the chamber 232 from outside. However, the method is not limited to this. For example, etching may be performed using a so-called direct plasma method, in which pre-plasma etching gas is supplied into the chamber 232 from the upper electrode, and high-frequency power is applied to each electrode to create plasma within the chamber 232.

[0049] [Protective film removal process] Figure 3B is an explanatory diagram of the protective film removal process. As shown in Figure 3B, in the protective film removal process performed after the processing process, the workpiece 100 is held on the holding table 241 of the protective film removal unit 240 via tape T. The protective film removal unit 240 includes a supply nozzle 242 provided above the holding table 241 and a water tank 243 for storing processing wastewater W. The permeate water introduction pipe 38 described above is connected to the supply nozzle 242. The water tank 243 is connected to the wastewater pipe 21 described above via an outlet pipe 244 at the bottom.

[0050] In the protective film removal process, permeate stored in the permeate tank 35 is supplied to the supply nozzle 242 by the drive of the water supply pump 37 (see Figure 1 for both), and the permeate is sprayed onto the upper surface of the workpiece 100 as cleaning water (processing water). As the cleaning water is supplied to the workpiece 100, the holding table 241 rotates, removing the mask 121 made of water-soluble resin. At this time, processing debris adhering to the mask 121 during the processing process is also removed along with the mask 121, and the workpiece 100 is cleaned.

[0051] In the protective film removal process, processing wastewater W containing the removed mask 121 and processing debris is stored in the water tank 243. The removed mask 121 becomes a dissolved water-soluble resin and is included in the processing wastewater W. The processing wastewater W, containing the dissolved water-soluble resin and processing debris, is then discharged from the water tank 243 to the wastewater treatment device 1. The processing wastewater W is filtered in the wastewater treatment device 1 as described above and then supplied to the supply nozzle 242 as washing water, and the washing water is circulated and used in the protective film removal process.

[0052] As described above, the processing apparatus 2 is limited to an apparatus that processes a workpiece 100 with a protective film 120 formed on it, but it may also be an other processing apparatus that processes a workpiece 100 with a protective film 120 formed on it and discharges processing wastewater W containing processing debris. For example, the processing apparatus 2 may be a cutting apparatus, and a cutting blade may be inserted along the grooves of a workpiece 100 with grooves formed on its surface by laser processing to fully cut the workpiece 100 and remove the protective film 120, and the processing wastewater W containing the protective film 120 and processing debris may be filtered through a hollow fiber membrane 12 (see Figure 1) and the permeate water may be used as processing water for the processing apparatus 2. A specific example of this will be explained below with reference to Figure 4.

[0053] Figure 4 shows another example of a workpiece processing method according to the embodiment. In the workpiece processing method shown in Figure 4, the process is carried out in the order of a holding step and a processing step. Figure 4A is an explanatory diagram of the holding step, and Figure 4B is an explanatory diagram of the processing step. Note that in Figure 4, the street 103 and device 104 of the workpiece 100 are not shown.

[0054] The processing apparatus 2 used in the processing method for the workpiece 100 shown in Figure 4 comprises a chuck table 261 that holds the workpiece 100 by suction via tape T, a water tank 273 capable of housing the chuck table 261, and a processing unit 280 provided above the chuck table 261.

[0055] Multiple clamping sections 262 for gripping the frame F are provided around the chuck table 261. The chuck table 261 is also provided to be movable in the X-axis direction (machining feed direction) by an X-axis movement mechanism 263. The water tank 273 is configured similarly to the water tank 243 in Figure 3B and is connected to the wastewater pipe 21 described above via an outlet pipe 274 at the bottom.

[0056] The machining unit 280 is mounted above the chuck table 261 so as to be movable in the Z-axis direction (vertical direction) by a Z-axis movement mechanism 281. The machining unit 280 includes a cutting blade 283 that rotates via a spindle 282 and a blade cover 284 that covers the area around the cutting blade 283. The machining unit 280 also includes a first nozzle 286 and a second nozzle 287 supported by the blade cover 284.

[0057] The first nozzles 286 are provided in pairs on both sides of the cutting blade 283, sandwiching it from the thickness direction, and the second nozzle 287 is provided in front of the cutting blade 283. The first nozzles 286 and the second nozzles 287 are connected to the permeate water introduction pipe 38 described above via the inside of the blade cover 284.

[0058] [Holding process] As shown in Figure 4A, during the holding process, the workpiece 100 is held by suction to the chuck table 261 via the tape T, and the frame F is clamped and fixed by multiple clamping parts 262.

[0059] [Processing process] After the holding process, a machining process is performed in which the workpiece 100 is machined by the machining unit 280, as shown in Figure 4B. During the machining process, permeate stored in the permeate tank 35 is supplied to the first nozzle 286 and the second nozzle 287 by the drive of the water supply pump 37 (see Figure 1 for both). As a result, the permeate is sprayed as machining water from the first nozzle 286 and the second nozzle 287 toward the cutting blade 283 and the machining point of the cutting blade 283 toward the workpiece 100. The cutting blade 283 and the machining point are cooled and cleaned by the spray of machining water.

[0060] In the machining process, starting from the state shown in Figure 4A, the machining unit 280 is lowered by the drive of the Z-axis movement mechanism 281, and the lower end of the cutting blade 283 is positioned midway across the thickness of the tape T. Then, the cutting blade 283 and the workpiece 100 are moved relative to each other in the X-axis direction, which is the machining feed direction, by the drive of the X-axis movement mechanism 263, and cutting is performed in the direction of extension of the street (not shown), cutting the workpiece 100. At this time, the cutting blade 283 and the machining point are cooled and cleaned by the spray of machining water from the first nozzle 286 and the second nozzle 287. By performing cutting on all the grid-like streets in the workpiece 100, a device chip containing one device each is formed.

[0061] During the processing step, the processing water sprayed from the first nozzle 286 and the second nozzle 287 is stored in the water tank 273 as processing wastewater W containing processing scraps from the cutting process. The processing wastewater W containing processing scraps is then discharged from the water tank 273 to the wastewater treatment device 1. The processing wastewater W is filtered in the wastewater treatment device 1 as described above and then supplied to the first nozzle 286 and the second nozzle 287 as processing water, and the processing water is circulated and used in the processing step.

[0062] It should be noted that the present invention is not limited to the above embodiments and can be implemented with various modifications. In the above embodiments, the present invention describes a method for processing a workpiece 100 equipped with a protective film 120, but even in a method for processing a workpiece 100 without a protective film 120, the processing wastewater W may be filtered by the wastewater treatment device 1 and supplied to the workpiece 100 as processing water for circulation. Furthermore, the processing device 2 is not limited to a cutting device, but may be a grinding device or a cutting device. In the above embodiments, the size and shape shown in the attached drawings are not limited thereto and can be appropriately modified within the scope that allows the present invention to be effective. In addition, it is possible to implement the present invention with appropriate modifications as long as they do not deviate from the scope of the objectives of the present invention.

[0063] In the above embodiment, the wastewater valve 22 and the air valve 28 are provided separately, but they may be changed to a single three-way valve connected to the tank 11, the wastewater pipe 21, and the supply pipe 27.

[0064] Furthermore, the wastewater treatment device 1 may be installed adjacent to the processing device 2, or it may be installed in a separate building or other location different from the building where the processing device 2 is installed.

[0065] Furthermore, the permeate filtered through the hollow fiber membrane 12 may be used or recovered in other devices instead of being used in the processing device 2. [Industrial applicability]

[0066] As described above, the present invention has the effect of reducing the overall size of the apparatus and decreasing the burden of maintenance by using high-pressure air from a high-pressure air supply source to pump processing wastewater. [Explanation of symbols]

[0067] 1: Wastewater treatment equipment 2: Processing equipment 11: Tank 12: Hollow fiber membrane 13: Case 16: Control Unit (Pressure Feeding Unit) 18: Tank entrance 19: Tank outlet 21: Wastewater pipe (pressure pumping section) 22: Wastewater valve (pressure pump section) 25: Air Inlet 27: Supply pipe (pressure pumping section) 28: Air valve (pressure supply section) 31: Case entrance 33: Case exit 35: Permeate Water Tank 37: Water pump 100: Work 101: Surface 120: Protective film 221: Chuck Table 231: Chuck Table 261: Chuck Table 280: Processing Unit AS: High-pressure air supply source W: Processing wastewater

Claims

1. A wastewater treatment apparatus that uses a hollow fiber membrane to remove processing wastewater containing processing scraps discharged from a processing apparatus that processes a workpiece using processing water, or processing wastewater containing at least a water-soluble resin discharged from a processing apparatus that processes a workpiece coated with a water-soluble resin, wherein the processing scraps and the water-soluble resin are removed. A wastewater treatment apparatus comprising: a tank for storing the processing wastewater; an air inlet located at the top of the tank for supplying high-pressure air to the tank from a high-pressure air supply source; a tank inlet for supplying the processing wastewater to the tank; a tank outlet for discharging the processing wastewater from the tank; a case housing the hollow fiber membrane; a case inlet for supplying the processing wastewater discharged from the tank outlet to the case; a case outlet for discharging the permeate that has passed through the hollow fiber membrane from the case; and a pumping unit for supplying high-pressure air to the tank after the processing wastewater has been supplied to the tank, thereby pressurizing the processing wastewater from the tank into the case.

2. The wastewater treatment apparatus according to claim 1, wherein the pressurizing unit comprises a supply pipe connecting the tank and the high-pressure air supply source, an air valve disposed in the supply pipe, a wastewater pipe connecting the processing apparatus and the tank, a wastewater valve disposed in the wastewater pipe, and a control unit that controls the opening and closing of the air valve and the wastewater valve.

3. The wastewater treatment apparatus according to claim 1, further comprising a permeate tank for temporarily storing the permeate discharged from the outlet of the case, and a water pump for supplying the permeate to the processing apparatus.

4. A processing apparatus comprising a chuck table for holding a workpiece, a processing unit for processing the workpiece, and a wastewater treatment apparatus according to any one of claims 1 to 3.

5. A method for processing a workpiece using the wastewater treatment device described in claim 3, A protective film forming step involves spreading the water-soluble resin onto the surface of the workpiece to form a protective film, A holding step in which the workpiece is held in a state in which the protective film is exposed by a chuck table, A processing step of processing the workpiece from the side of the protective film, A method for processing a workpiece, comprising a protective film removal step, which involves removing the protective film using water treated by the wastewater treatment device after the processing step.

6. A method for processing a workpiece using the wastewater treatment apparatus described in claim 3, A holding step in which the workpiece is held by a chuck table, A method for processing a workpiece, comprising: a processing step of supplying water treated by the wastewater treatment device to the workpiece as processing water, while processing the workpiece with a processing unit.

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