Cleaning equipment

Abstract

To provide a cleaning device capable of improving supply efficiency of cleaning water to a material to be cleaned by reducing an installation space of a pure water generating device, facilitating water quality management of cleaning water, and simplifying a supply mechanism of cleaning water to the material to be cleaned.SOLUTION: A cleaning device for cleaning a material to be cleaned using cleaning water, recovering waste liquid, and reproducing and circulating pure water comprises: a holding table for holding the material to be cleaned; a cleaning water supply nozzle for supplying cleaning water to the material to be cleaned held on the holding table; a waste liquid tank for storing cleaning water which is used as waste liquid; a waste liquid pump for pumping up the waste liquid from the waste liquid tank; a filter for filtering the waste liquid pumped up by the waste liquid pump and refining the filtered liquid into fresh water; a fresh water tank for storing fresh water; an ultraviolet light source for irradiating the fresh water with ultraviolet light; a fresh water pump for pumping up the fresh water from the fresh water tank; an ion exchange resin unit for refining pure water by bringing the fresh water pumped up by the fresh water pump into contact with an ion exchange resin; and a specific resistance value meter for measuring a specific resistance value of the pure water.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a cleaning apparatus for cleaning a workpiece, such as a wafer made of a semiconductor material, after the workpiece has been processed by a processing apparatus. [Background technology]

[0002] In the manufacturing process of device chips to be mounted on electronic devices, first, multiple planned dividing lines (streets) that intersect with each other are set on the surface of a wafer made of semiconductor material. Then, devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integration) are formed in each area partitioned by the planned dividing lines. After that, the wafer is divided along the planned dividing lines to obtain multiple device chips. To divide the wafer, a cutting device that cuts the wafer with an annular cutting blade is used.

[0003] In recent years, with the trend toward smaller and thinner electronic devices, there has been a demand for thinner device chips as well. Therefore, wafers are sometimes thinned by grinding the backside of the wafer before being divided. Wafer grinding is performed using a grinding device or the like that grinds the wafer with a grinding wheel equipped with multiple grinding stones.

[0004] After processing a workpiece such as a wafer using a processing device such as the cutting device or grinding device, the workpiece needs to be cleaned to remove processing debris generated during processing. Therefore, the processing device is equipped with a cleaning device that sprays cleaning water onto the workpiece to clean it (see Patent Documents 1 and 2). The processed workpiece is cleaned in the cleaning device.

[0005] In a cleaning device, pure water is sprayed onto an object to be cleaned, such as a workpiece, as cleaning water. Then, waste liquid containing processing debris adhering to the object to be cleaned is discharged from the cleaning device and disposed of. However, a large amount of pure water is used in the cleaning device, and disposal of the discharged waste liquid incurs a non-negligible cost. Therefore, a pure water generating device (waste liquid processing device) is known that purifies and regenerates waste liquid to generate pure water that can be reused as cleaning water (see Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-180739 [Patent Document 2] Japanese Patent Application Publication No. 2020-136300 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-190128 Summary of the Invention [Problem to be solved by the invention]

[0007] Conventionally, when a pure water generator is installed adjacent to a cleaning device, it is necessary to secure an installation space for the pure water generator in addition to the installation space for the cleaning device near the processing device. This is because if the pure water generator is installed far from the cleaning device, it becomes difficult to control the quality of the pure water generated in the pure water generator and sent to the cleaning device.

[0008] Furthermore, the pure water generating device must be equipped with a pump mechanism for delivering pure water to the cleaning device regardless of the distance from the cleaning device. The cleaning device must also be equipped with a pump mechanism for supplying cleaning water, such as pure water, to the object to be cleaned, such as a workpiece. Thus, it is necessary to operate multiple pump mechanisms to supply pure water reclaimed from waste liquid as cleaning water to the object, which can sometimes reduce the cleaning efficiency of the object.

[0009] The present invention has been made in consideration of such problems, and its object is to provide a cleaning device that reduces the installation space of a pure water generating device, facilitates water quality control of cleaning water, and increases the efficiency of supplying cleaning water by simplifying the mechanism for supplying cleaning water to the object to be cleaned. [Means for solving the problem]

[0010] According to one aspect of the present invention, a cleaning device that cleans an object to be cleaned using cleaning water, recovers waste liquid, and regenerates and circulates pure water includes a holding table that holds the object to be cleaned, a cleaning water supply nozzle that supplies cleaning water to the object to be cleaned held on the holding table, a waste liquid tank that stores the cleaning water used to clean the object to be cleaned as waste liquid, a waste liquid pump that draws the waste liquid from the waste liquid tank, a filter that filters the waste liquid drawn by the waste liquid pump to purify it into pure water, a fresh water tank that stores the pure water, an ultraviolet light source that irradiates the pure water with ultraviolet light, a fresh water pump that draws the pure water from the fresh water tank, an ion exchange resin unit that purifies pure water by contacting the pure water drawn by the fresh water pump with an ion exchange resin, and a resistivity meter that measures the resistivity of the pure water. a switching valve connected to a first flow path leading to the waste liquid tank and a second flow path leading to the cleaning water supply nozzle, and switching the destination of the pure water between the first flow path and the second flow path based on the resistivity of the pure water; Preparation When the resistivity of the pure water measured by the resistivity meter is below a threshold, the switching valve switches the outflow destination of the pure water to the first flow path, and when the resistivity of the pure water measured by the resistivity meter exceeds a threshold, the switching valve switches the outflow destination of the pure water to the second flow path. A cleaning device is provided, characterized in that

[0011] Preferably, the device has a housing that houses the holding table, the cleaning water supply nozzle, the waste liquid tank, the waste liquid pump, the filter, the fresh water tank, the ultraviolet light source, the fresh water pump, the ion exchange resin unit, and the resistivity meter.

[0012] Preferably, the apparatus further comprises a precision filter for filtering the pure water purified by the ion exchange resin unit before the resistivity is measured by the resistivity meter.

[0014] Still preferably, the clean water pump functions as a supply drive source for supplying the pure water to the cleaning water supply nozzle when the switching valve directs the pure water to the second flow path. [Effects of the Invention]

[0015] A cleaning apparatus according to one aspect of the present invention includes a holding table and a cleaning water supply nozzle, and can clean an object with cleaning water. It also includes a waste liquid tank, a waste liquid pump, a filter, a fresh water tank, an ultraviolet lamp, a fresh water pump, and an ion exchange resin unit, and can purify used cleaning water to produce pure water. It also includes a resistivity meter, and pure water whose quality has been confirmed to meet a predetermined standard is supplied to the object from the cleaning water supply unit.

[0016] A cleaning apparatus according to one aspect of the present invention can clean an object to be cleaned and regenerate cleaning water. Therefore, there is no need to prepare a separate pure water generator, and the space required for installing the pure water generator can be reduced. Furthermore, since the flow path for purified pure water is extremely short, water quality control of the pure water supplied to the object to be cleaned is also easy. Furthermore, since the cleaning apparatus can supply pure water purified in the ion exchange resin unit directly to the object to be cleaned from the cleaning water supply unit, the supply drive source for supplying cleaning water to the object to be cleaned can be simplified.

[0017] Therefore, the present invention provides a cleaning device that reduces the installation space of the pure water generating device, facilitates water quality management of the cleaning water, and increases the efficiency of supplying cleaning water by simplifying the mechanism for supplying cleaning water to the object to be cleaned. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is a perspective view schematically showing a cleaning device. [Figure 2] FIG. 2 is a perspective view schematically showing a holding table and a cleaning water supply unit. [Figure 3] FIG. 2 is a structural diagram schematically illustrating the configuration of a purification unit inside the cleaning device. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. First, an object to be cleaned by the cleaning device according to this embodiment will be described. In the cleaning device, a workpiece processed by a processing device such as a cutting device or a grinding device is cleaned as the object to be cleaned.

[0020] In a processing device, a workpiece such as a wafer made of a semiconductor material such as Si (silicon) or SiC (silicon carbide) is processed. A plurality of devices such as ICs and LSIs are formed on the surface of the wafer. When the wafer is divided into individual devices, individual device chips are formed. Furthermore, if the back side of the wafer is ground in advance to thin the wafer before dividing it, thin device chips can be obtained.

[0021] The workpiece to be processed by the processing device may be pre-assembled with a ring frame made of metal or the like and an adhesive tape attached to the opening of the ring frame. That is, the workpiece is attached to the adhesive surface of the adhesive tape exposed in the opening of the ring frame, becoming part of the frame unit. Forming the frame unit makes it easier to handle the workpiece. Furthermore, when the workpiece is divided into individual chips, each chip remains supported by the adhesive tape, making it easier to handle each chip.

[0022] When a workpiece is processed in a processing device, processing debris is generated. In the processing device, the workpiece is processed while processing water such as pure water is supplied, and the resulting processing debris is washed away with the processing water. However, if the processing water containing the processing debris remains on the workpiece and the surface of the workpiece dries, the processing debris will stick to the surface of the workpiece. Therefore, it is necessary to start cleaning quickly before the surface of the processed workpiece dries.

[0023] For this reason, a cleaning device for cleaning a processed workpiece is installed near the processing device, or the cleaning device is incorporated inside the processing device. Next, a cleaning device according to this embodiment will be described using an example of a cleaning device installed near the processing device.

[0024] 1 is a perspective view schematically illustrating a cleaning device 2. The cleaning device 2 includes, on its exterior, a rectangular parallelepiped housing 4 that houses the various components, a transparent opening / closing cover 6 that closes the top of the internal space of the housing 4, and the like.

[0025] The housing 4 is supported by four support legs 14, and the tilt of the housing 4 can be corrected by adjusting the length of each support leg 14. A cleaning space 16 (see FIG. 2) where the object to be cleaned is cleaned is provided inside the opening / closing cover 6 at the top of the housing 4. When the opening / closing cover 6 is opened, the object to be cleaned can be carried in and out of the cleaning space 16.

[0026] The cleaning device 2 includes a control unit 8 inside the housing 4 that controls each component and operates each component so that the object to be cleaned can be cleaned under predetermined cleaning conditions. The control unit 8 is configured by a computer including, for example, a processing device such as a processor represented by a CPU (Central Processing Unit), a main memory device such as a DRAM (Dynamic Random Access Memory), an SRAM (Static Random Access Memory), or a ROM (Read Only Memory), and an auxiliary memory device such as a flash memory, a hard disk drive, or a solid state drive.

[0027] The auxiliary storage device stores software including a predetermined program. The functions of the control unit 8 are realized by operating the processing device in accordance with this software. Then, by operating the processing device in accordance with the software such as the program stored in the auxiliary storage device, the software and the processing device (hardware resource) function as a concrete means in cooperation with each other.

[0028] The cleaning device 2 further includes a touch panel display 10 that functions as both a display unit that displays various information and an input interface used to input various commands. The cleaning device 2 also includes an alarm lamp 12 that indicates the status of the cleaning device 2, such as its operating status and the presence or absence of errors. An emergency stop button 18 that can be used to forcefully terminate the operation of the cleaning device 2 is also provided on the exterior of the cleaning device 2.

[0029] Next, the components that contribute to cleaning the object to be cleaned in the cleaning device 2 will be described. Figure 2 is a perspective view that schematically shows the cleaning space 16 inside the cleaning device 2. The cleaning space 16 is a space surrounded by a rectangular water case 16a, and a cleaning unit 20 is provided in the cleaning space 16. A duct (not shown) for intake and exhaust is connected to the water case 16a. The cleaning unit 20 includes a spinner table mechanism 22, a cleaning water receiving mechanism 24 that surrounds the periphery of the spinner table mechanism 22, and a cleaning mechanism 26 that cleans the object to be cleaned.

[0030] Spinner table mechanism 22 has a holding table (spinner table) 28 and a motor (not shown) that rotates holding table 28 around an axis that is perpendicular to the upper surface. A porous member 28a that is exposed upward is disposed on the top of holding table 28. A suction path (not shown) is disposed inside holding table 28, one end of which is connected to a suction source (not shown) and the other end of which is connected to porous member 28a.

[0031] When an object to be cleaned is placed on the holding table 28 and the suction source is activated to apply negative pressure to the object through the suction path and porous member 28a, the object is sucked and held on the holding table 28. In other words, the upper surface of the holding table 28 becomes the holding surface. The upper end of an output shaft 30 is connected to the lower part of the holding table 28, and a motor (not shown) is connected to the lower end of the output shaft 30. The output shaft 30 transmits the rotational force generated by the motor to the holding table 28.

[0032] The flush water receiving mechanism 24 comprises an annular bottom wall 34 that projects radially inward from the lower part of the water case 16a, and a cylindrical outer peripheral wall 32 made of sheet metal or the like that stands upright from the bottom wall 34 outside the holding table 28. The output shaft 30 passes vertically inside the bottom wall 34. A drain port (not shown) is provided in the bottom wall 34, and a drain channel that leads to a waste liquid tank (described below) is connected to the drain port. When flush water falls into the flush water receiving mechanism 24, the drain port flows through a drain channel 44 (described below) (see FIG. 3) from the drain port and reaches a waste liquid tank 46 (described below) (see FIG. 3).

[0033] A pipe-shaped shaft 36 of the cleaning mechanism 26 passes through the outer periphery of the bottom wall 34. The shaft 36 is a pipe-shaped member that extends outside the holding table 28 in a direction perpendicular to the upper surface of the holding table 28, reaches a position higher than the height of the upper surface of the holding table 28, and has two arms 38 connected to its upper end. A motor (not shown) that rotates the shaft 36 is connected to the base end of the shaft 36, and the shaft 36 is rotated in the perpendicular direction by the motor.

[0034] The arms 38 are pipe-shaped members that extend in a direction perpendicular to the extension direction of the shaft 36, with a length equivalent to the distance from the shaft 36 to the center of the holding table 28, and a downward-facing cleaning water supply nozzle 40 is disposed at the tip of each arm 38.

[0035] As will be described later, the cleaning device 2 includes a purification unit 42 that serves as a cleaning water supply source, and has the function of spraying cleaning water from a cleaning water supply nozzle 40 via a shaft 36 and an arm 38 toward an object to be cleaned held on the holding table 28, thereby removing machining debris and the like adhering to the object to be cleaned. For example, the cleaning water is pure water. To more powerfully clean the object to be cleaned, high-pressure gas may be mixed into the cleaning water supplied from the cleaning water supply nozzle 40, and cleaning may be performed in the cleaning device 2 using a mixed fluid of pure water and high-pressure gas.

[0036] Clamps 28b that hold the ring frame of the frame unit having the object to be cleaned are disposed on the outer periphery of the upper part of holding table 28. When the centrifugal force generated by the rotation of holding table 28 moves the lower weight part of clamp 28b to the outer periphery, the upper gripping part automatically falls to the inner periphery and grips the ring frame.

[0037] When cleaning an object to be cleaned in the cleaning unit 20, the object to be cleaned is held by suction on the holding table 28, and the holding table 28 is rotated at high speed, and the shaft 36 is rotated to move the cleaning water supply nozzle 40 back and forth above the holding table 28. Then, a cleaning fluid (typically a mixed fluid of pure water and high-pressure air) is sprayed from the cleaning water supply nozzle 40 toward the object to be cleaned, and the object to be cleaned is cleaned.

[0038] The used cleaning water, which has been sprayed onto the object to be cleaned and has taken in the processing debris, falls onto the bottom wall 34 of the cleaning water receiving mechanism 24 and is discharged from the drain outlet to the outside of the cleaning space 16. Conventionally, the used cleaning water has been discharged as waste liquid to the outside of the cleaning device 2 and disposed of. However, the amount of pure water used in the cleaning device 2 is large, and disposal of the waste liquid has involved significant costs.

[0039] Therefore, a pure water generator that purifies the waste liquid discharged from the cleaning device 2 to produce pure water has been installed and used near the cleaning device 2. The pure water generator, for example, filters the waste liquid to produce pure water, irradiates the pure water with ultraviolet light to destroy organic matter, and uses ion exchange resin to remove impurity ions from the pure water to produce pure water. The produced pure water is then supplied to the cleaning device 2.

[0040] However, in the past, when a pure water generator was installed adjacent to the cleaning device 2, it was necessary to secure installation space for the pure water generator near the processing device. This is because if the pure water generator was installed at a location far from the cleaning device 2, it would be difficult to control the quality of the pure water generated in the pure water generator and transferred to the cleaning device 2.

[0041] Furthermore, the pure water generating device must be equipped with a pump mechanism for sending pure water to the cleaning device 2 regardless of the distance from the cleaning device 2. The cleaning device 2 must then be equipped with a pump mechanism for supplying cleaning water to the object to be cleaned. In this way, it is necessary to operate multiple pump mechanisms to supply pure water reclaimed from waste liquid to the object to be cleaned as cleaning water, which can sometimes be a factor in reducing the cleaning efficiency of the object to be cleaned.

[0042] Therefore, the cleaning device 2 according to this embodiment is provided with a purification unit 42 at the bottom of the internal space of the housing 4. The purification unit 42 purifies used cleaning water to generate pure water, and sends the pure water having a water quality that meets a predetermined standard as cleaning water to the cleaning space 16. Next, the purification unit 42 will be described.

[0043] Fig. 3 is a diagram showing the configuration of the purification unit 42 and the connections between the components. For ease of explanation, Fig. 3 shows a simplified linear representation of part of the flow path. The flow path is constructed, for example, with metal or resin piping, tubes, etc.

[0044] The purification unit 42 includes a drainage channel 44 and a waste liquid tank 46 provided at the end of the drainage channel 44. The cleaning water (waste liquid) discharged from the cleaning space 16 flows down the drainage channel 44 and is supplied to the waste liquid tank 46 and stored therein. Specifically, water containing foreign matter such as processing waste and impurity ions is supplied to the waste liquid tank 46 as waste liquid.

[0045] A waste liquid pump 48 is connected to the waste liquid tank 46, which pumps up and sends out the waste liquid stored in the waste liquid tank 46. The waste liquid pump 48 is a pump that supplies the water (waste liquid) stored in the waste liquid tank 46 to the filter 50. The amount of water supplied from the waste liquid tank 46 to the filter 50 is controlled by the waste liquid pump 48.

[0046] The filter 50 is made of, for example, activated carbon, zeolite, cloth, resin fiber, glass fiber, metal mesh, a reverse osmosis membrane (RO membrane), or the like. The filter 50 removes impurities such as processing waste contained in the waste liquid pumped by the waste liquid pump 48 by adsorbing or filtering them out. In other words, the waste liquid is filtered to purify it into clean water. The clean water filtered by the filter 50 is stored in a clean water tank 52 that can store clean water.

[0047] Inside the fresh water tank 52, an ultraviolet light source 54 is provided, which irradiates the fresh water contained in the fresh water tank 52 with ultraviolet light. The ultraviolet light source 54 is, for example, an ultraviolet lamp, an ultraviolet fluorescent lamp, an ultraviolet LED, or the like. The water used in the cleaning device 2 may be contaminated with impurities, such as microorganisms floating in the air. Therefore, the ultraviolet light source 54 irradiates the water with ultraviolet light in order to sterilize the fresh water. Furthermore, irradiating the fresh water with ultraviolet light can destroy other organic matter contained in the fresh water.

[0048] Here, it is preferable that the ultraviolet light irradiated onto the fresh water by the ultraviolet light source 54 contains a 254 nm wavelength component and a 185 nm wavelength component. When the fresh water is irradiated with ultraviolet light having a wavelength of 254 nm, the fresh water can be sterilized. When microorganisms die, their bodies are left in the water. In addition, other organic matter is also mixed into the fresh water. The ultraviolet light having a wavelength of 185 nm activates the ozone contained in the fresh water and promotes the decomposition of organic matter by the ozone.

[0049] A fresh water pump 56 is connected to the fresh water tank 52 via a flow path. The fresh water pump 56 has a function of pumping fresh water from the fresh water tank 52 and sending it downstream of the flow path. The ultraviolet light source 54 may be provided in the flow path through which the fresh water pumped up by the fresh water pump 56 flows, and ultraviolet light from the ultraviolet light source 54 may be irradiated onto the fresh water flowing through the flow path.

[0050] An ion exchange resin unit 58 is connected to the flow path downstream of the fresh water tank 52. The ion exchange resin unit 58 contains ion exchange resin and exchanges ions contained in the water irradiated with ultraviolet light from the ultraviolet light source 54. The ion exchange resin unit 58 has, for example, a cylindrical container and ion exchange resin filled in the container. A flow path is formed inside the container through which water flows between the ion exchange resin, and water entering the ion exchange resin unit 58 passes between the ion exchange resin within the container.

[0051] For example, the container contains a mixture of an ion exchange resin (cation exchange resin) that exchanges cations and an ion exchange resin (anion exchange resin) that exchanges anions. Ions contained in the water supplied to the ion exchange resin unit 58 other than hydrogen ions and hydroxide ions are exchanged for hydrogen ions or hydroxide ions. That is, the ion exchange resin unit 58 purifies the pure water by bringing the fresh water pumped up by the fresh water pump 56 into contact with the ion exchange resin.

[0052] The outlet of the ion exchange resin unit 58 is connected to a flow path, and the water (pure water) whose ions have been exchanged by the ion exchange resin travels through the flow path to reach the precision filter 60. The precision filter 60 has the function of finally filtering the water (pure water) whose ions have been exchanged by the ion exchange resin unit 58.

[0053] Like the filter 50, the precision filter 60 includes a filter (not shown) made of, for example, activated carbon, zeolite, cloth, resin fiber, glass fiber, metal mesh, reverse osmosis membrane (RO membrane), or the like.

[0054] The water discharged as wastewater from the cleaning device 2 is purified as it travels through the flow path of the purification unit 42, and reaches the final stage of purification when it reaches the precision filter 60. Because the impurities contained in the water are extremely small and in trace amounts, the precision filter 60 is required to have performance suitable for removing such impurities. For example, it is preferable that the precision filter 60 use a membrane with finer mesh than the filter 50.

[0055] The precision filter 60 further purifies the water by adsorbing or filtering out trace amounts of impurities contained in the inflowing water. The water (pure water) filtered by the precision filter 60 proceeds downstream through the flow path to a resistivity meter 62 that measures the resistivity of the water (pure water).

[0056] The resistivity of water increases as the amount of impurities contained in the water decreases. Therefore, by measuring the resistivity of water (pure water) with the resistivity meter 62, it can be determined whether the purified pure water is of a quality suitable for reuse as cleaning water in the cleaning device 2. For example, the resistivity meter 62 is connected to the control unit 8, which stores a threshold value for determining whether the water is of a quality suitable for use as cleaning water. The control unit 8 determines whether the pure water is of a good quality based on the resistivity value of the pure water transmitted from the resistivity meter 62.

[0057] The purification unit 42 is provided with a switching valve 66 at the end of a flow path 64 through which water (pure water) whose resistivity has been measured by the resistivity meter 62 flows. The switching valve 66 is connected to a first flow path 68 that leads to the waste liquid tank 46 and a second flow path 70 that leads to the cleaning water supply nozzle 40 in the cleaning space 16. The switching valve 66 is, for example, a solenoid valve connected to the control unit 8. The switching valve 66 has the function of switching the outflow destination of the water that flows in through the flow path 64 between the first flow path 68 and the second flow path 70.

[0058] When the resistivity of the water (pure water) measured by the resistivity meter 62 does not exceed a predetermined threshold, the control unit 8 determines that the quality of the water (pure water) does not meet the standard for use as cleaning water for cleaning the object to be cleaned. In this case, if the water is sent as is to the cleaning water supply nozzle 40, cleaning water of a quality that does not meet the predetermined standard will be supplied to the object to be cleaned, and the object will not be cleaned sufficiently.

[0059] Therefore, the control unit 8 controls the switching valve 66 to switch the outflow destination of the water to the first flow path 68, and sends the water (pure water) to the waste liquid tank 46. Then, the water whose quality does not meet the predetermined standard flows again through the flow path of the purification unit 42 together with the water stored in the waste liquid tank 46, and is further purified. In this case, the water stored in the waste liquid tank 46 is gradually purified.

[0060] Then, when the resistivity of the water (pure water) measured by the resistivity meter 62 gradually increases and exceeds a predetermined threshold, the control unit 8 determines that the quality of the water (pure water) meets a standard that allows it to be used as cleaning water for cleaning the object to be cleaned. At this time, the control unit 8 controls the switching valve 66 to switch the water outflow destination to the second flow path 70. Then, the pure water that has been confirmed to be of a predetermined level of water quality is supplied to the cleaning water supply nozzle 40 as cleaning water, and the cleaning water is supplied from the cleaning water supply nozzle 40 to the object to be cleaned.

[0061] Next, we will explain the cleaning operation of the object to be cleaned in the cleaning device 2. When cleaning the object to be cleaned, first, the object to be cleaned is sucked and held by the holding table 28 of the spinner table mechanism 22, and the holding table 28 starts to rotate, and the cleaning water supply nozzle 40 is made to move back and forth above the object to be cleaned.

[0062] Next, the purification unit 42 is started to operate to start purifying the water, and pure water that meets a predetermined level of water quality is sent as cleaning water to the cleaning water supply nozzle 40, which then supplies the cleaning water to the object to be cleaned from the cleaning water supply nozzle 40. At this time, high-pressure gas may be mixed with the cleaning water, and two fluids may be sprayed from the cleaning water supply nozzle 40.

[0063] The cleaning water supplied to the object to be cleaned picks up processing debris and the like adhering to the surface of the object to be cleaned, and reaches the waste liquid tank 46 of the purification unit 42. Then, while the purification unit 42 is operating, the water stored in the waste liquid tank 46 is purified and recycled as cleaning water, which is then supplied again to the object to be cleaned from the cleaning water supply nozzle 40.

[0064] At this time, if the resistivity of the water measured by the resistivity meter 62 drops below a predetermined threshold, the control unit 8 controls the switching valve 66 to switch the water outflow destination from the second flow path 70 to the first flow path 68, and stops the supply of water to the cleaning water supply nozzle 40. In this case, it is possible to prevent water that does not meet the predetermined level from being supplied to the object to be cleaned, thereby preventing re-contamination of the object to be cleaned, etc.

[0065] Then, if the resistivity of the water measured by the resistivity meter 62 increases while the purification unit 42 continues to operate and exceeds a predetermined threshold, the control unit 8 controls the switching valve 66 to switch the water outflow destination from the first flow path 68 to the second flow path 70. In other words, the supply of water to the cleaning water supply nozzle 40 is resumed, and cleaning water whose quality meets a predetermined standard is supplied to the object to be cleaned.

[0066] When the cleaning water has been sprayed onto the object for a predetermined time, the supply of cleaning water from the cleaning water supply nozzle 40 is stopped, and the rotation of the holding table 28 continues to dry the object. This completes the cleaning of the object. After the object has sufficiently dried, the rotation of the holding table 28 is stopped, and the suction and holding of the object by the holding table 28 is released. The object is then carried out of the cleaning device 2.

[0067] It should be noted that as the object to be cleaned continues to be cleaned in the cleaning device 2, some of the circulating water may evaporate and be lost from the cleaning device 2. In this case, the manager of the cleaning device 2 can maintain a predetermined amount of water circulation in the cleaning device 2 by periodically adding water to the cleaning water receiving mechanism 24 to replenish it. The cleaning device 2 may also be connected to a water supply pipe connected to a water source, and water may be supplied through the water supply pipe when the amount of water circulating inside decreases.

[0068] As explained above, with the cleaning apparatus 2 according to this embodiment, unlike when an independent pure water generator is used, there is no need to secure installation space for the pure water generator in addition to the installation space for the cleaning apparatus 2 near the processing apparatus. Furthermore, the flow path from the purification unit 42 to the cleaning water supply nozzle 40 can be made extremely short, and the quality of the cleaning water can be checked immediately before it reaches the cleaning water supply nozzle 40, making it extremely easy to manage the quality of the cleaning water.

[0069] Furthermore, when an independent pure water generator is connected to a cleaning device as in the past, the pure water generator must be equipped with a pump mechanism for delivering pure water to the cleaning device, and the cleaning device must be equipped with a pump mechanism for supplying cleaning water to the cleaning water supply nozzle. In contrast, in the cleaning device 2 according to this embodiment, the pure water pump 56 of the purification unit 42 serves the functions of both pump mechanisms and also functions as a drive source for supplying cleaning water. Therefore, cleaning water can be supplied to the object to be cleaned with a simple configuration, reducing water supply costs and improving the cleaning efficiency of the object to be cleaned.

[0070] It is also possible to incorporate a purification unit 42 into the processing equipment that processes the workpieces, purifying and regenerating the processing water used in the processing equipment while supplying the processing water to the workpieces and processing units. However, if the quality of the regenerated water during processing of the workpieces falls below a predetermined level, continuing to supply the processing water will cause problems, since the required processing quality cannot be maintained. On the other hand, stopping the supply of processing water during processing of the workpieces will also cause problems, since the required processing quality cannot be maintained.

[0071] In contrast, in the washing device 2 according to this embodiment, if the quality of the water regenerated in the purification unit 42 does not meet a predetermined standard while the object is being washed, stopping the supply of washing water to the object is unlikely to cause a major problem. If the purification unit 42 continues to purify the water, and the supply of washing water is resumed when the water quality meets a predetermined standard, the object can be sufficiently washed.

[0072] That is, in the cleaning device 2 according to this embodiment, the object can be cleaned without any problems even when the supply of cleaning water is unstable. This is the reason why it is possible to omit a pure water tank for storing purified water and a pump mechanism as a driving source for supplying cleaning water from the pure water tank to the cleaning water supply nozzle 40.

[0073] However, the cleaning apparatus 2 according to this embodiment may have such a pure water tank and a pump function. For example, if the cleaning apparatus 2 has a pure water tank or the like, it can store pure water of a water quality that meets a predetermined standard, allowing cleaning water to be continuously supplied stably by the cleaning water supply nozzle 40. Furthermore, if temperature control of the cleaning water is required, the temperature of the cleaning water can be adjusted by providing the pure water tank with a temperature control mechanism such as a heat source, such as an electric heating wire, or a cooling source, such as a Peltier element.

[0074] In the above embodiment, the cleaning device 2 has the switching valve 66, and water whose quality does not meet a predetermined standard is returned to the waste liquid tank 46. However, one aspect of the present invention is not limited to this. That is, the cleaning device 2 does not have to be equipped with the switching valve 66 and the first flow path 68. Unlike processing water used in processing devices that process workpieces, the cleaning water supplied to the object to be cleaned by the cleaning device 2 is less likely to cause damage to the object to be cleaned, even if the water quality does not meet a predetermined standard.

[0075] In this case, the end condition for cleaning the object may be, for example, when pure water whose water quality has been confirmed to meet a predetermined standard by measuring the resistivity with the resistivity meter 62 has been continuously supplied to the object for more than a predetermined time. In this case, the cleaning time count may be reset to zero when the quality of the water supplied to the object no longer meets the predetermined standard, and may be restarted when it is confirmed that the water quality meets the predetermined standard, and cleaning may be terminated when the cleaning time has exceeded the predetermined time.

[0076] In this way, the object can be sufficiently washed even when the washing device 2 does not have the switching valve 66. In this case, water is constantly supplied to the object, so there is no risk of the object drying out during the washing process.

[0077] Furthermore, in the above embodiment, the cleaning device 2 is installed adjacent to the processing device, but the cleaning device 2 according to this embodiment is not limited to this. That is, the cleaning device 2 may be incorporated into the processing device that processes the workpiece.

[0078] In addition, the structures, methods, etc. according to the above-described embodiments can be modified as appropriate without departing from the scope of the object of the present invention. [Explanation of symbols]

[0079] 2. Cleaning equipment 4. Cabinet 6 Opening and closing cover 8. Control Unit 8a Porous material 10 Touch panel display 12 Alarm lamp 14 Support legs 16 Cleaning space 16a Water Case 18 Emergency stop button 20 Cleaning Unit 22 Spinner table mechanism 24 Cleaning water receiving mechanism 26 Cleaning mechanism 28 Holding table 28a Porous material 28b Clamp 30 Output shaft 32 Outer wall 34 Bottom wall 36 Shaft 38 Arm 40 Cleaning water supply nozzle 42 Purification Unit 44 Drainage Channel 46 Waste liquid tank 48 Wastewater Pump 50 filters 52 Fresh water tank 54 Ultraviolet light source 56 Fresh water pump 58 Ion exchange resin unit 60 Precision Filters 62 Resistivity meter 64 flow paths 66 Switching valve 68 First Channel 70 Second Channel

Claims

1. A cleaning device that uses cleaning water to clean an object, collects waste liquid, and regenerates and circulates pure water, a holding table for holding the object to be cleaned; a cleaning water supply nozzle for supplying cleaning water to the object to be cleaned held on the holding table; a waste liquid tank for storing the cleaning water used to clean the object as waste liquid; a waste liquid pump that pumps the waste liquid from the waste liquid tank; a filter that filters the waste liquid pumped up by the waste liquid pump to purify it into clean water; a fresh water tank for storing the fresh water; an ultraviolet light source that irradiates the pure water with ultraviolet light; a fresh water pump that pumps the fresh water from the fresh water tank; an ion exchange resin unit that purifies the pure water by bringing the fresh water pumped up by the fresh water pump into contact with an ion exchange resin; a resistivity meter for measuring the resistivity of the pure water; a switching valve connected to a first flow path leading to the waste liquid tank and a second flow path leading to the cleaning water supply nozzle, for switching a destination of the pure water between the first flow path and the second flow path based on the resistivity value of the pure water; a switching valve for switching the outflow destination of the pure water to the first flow path when the resistivity value of the pure water measured by the resistivity meter is below a threshold value, and a switching valve for switching the outflow destination of the pure water to the second flow path when the resistivity value of the pure water measured by the resistivity meter exceeds a threshold value.

2. 2. The cleaning device according to claim 1, further comprising a housing that houses the holding table, the cleaning water supply nozzle, the waste liquid tank, the waste liquid pump, the filter, the fresh water tank, the ultraviolet light source, the fresh water pump, the ion exchange resin unit, and the resistivity meter.

3. 3. The cleaning device according to claim 1, further comprising a precision filter for filtering the pure water purified by the ion exchange resin unit before the resistivity is measured by the resistivity meter.

4. 4. The cleaning apparatus according to claim 1, wherein the clean water pump functions as a supply drive source that supplies the pure water to the cleaning water supply nozzle when the switching valve directs the pure water to the second flow path.

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