How to clean the cover

Abstract

To effectively clean and remove fouling on an inner wall in the case of cleaning the inner wall of a cover of a cleaning device.SOLUTION: A method of cleaning an inner wall 348 of a cover 34 of a cleaning device 3, comprises at least: a table 30 including a holding surface 302 that holds a substrate 19; a cleaning water supply nozzle 35 that supplies a cleaning water 356 to the substrate 19 held by the table 30; and the cover 34 that surrounds an outer periphery of the table 30. The method includes: a step of supply the cleaning water 356 by the cleaning water supply nozzle 35 to the holding surface 302 and accumulating the cleaning water 356 onto the holding surface 302; a step of splashing the cleaning water 356 accumulated onto the table 30 in the accumulation step to the inner wall 348 of the cover 34 while rotating the table 30; and a step of removing the cleaning water 356 attached to the inner wall 348 of the cover 34 by a wind pressure by the rotation while rotating the table 30 after the execution of a discharge step.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for cleaning a cover of a cleaning device, for cleaning the inner wall of the cover. [Background technology]

[0002] BACKGROUND ART For cleaning semiconductor substrates, a cleaning apparatus is used that cleans the substrate by rotating a holding table while supplying cleaning water to the substrate held on the holding table (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-015347 Summary of the Invention [Problem to be solved by the invention]

[0004] The cleaning space of the cleaning device is surrounded by a cylindrical cover, but because the cleaning water splashes, foreign matter removed by cleaning adheres to the inner wall of the cover, causing contamination, and the contamination adhering to the inner wall falls onto the substrate, potentially recontaminating the substrate.

[0005] The conventional cleaning method for the inner wall of the cover involves supplying cleaning water to the top surface of a holding table placed inside the cover while rotating the table at a constant speed, atomizing and diffusing the cleaning water to wet the inner wall of the cover. However, because the cleaning water is atomized, the diameter of the water droplets that hit the cover is small, which reduces the amount of water at the impact point, resulting in a weak cleaning effect.

[0006] Therefore, when cleaning the inner wall of the cover of a cleaning device, there is a problem of how to more effectively clean and remove dirt from the inner wall. [Means for solving the problem]

[0007] A cleaning method for cleaning an inner wall of a cover of a cleaning apparatus including at least a holding table having a holding surface for holding a substrate, a cleaning water supply nozzle for supplying cleaning water to the substrate held on the holding table, and a cover surrounding an outer periphery of the holding table, the method comprising: The holding surface holds a frame unit configured such that a sheet is adhered to an annular frame having an opening so as to close the opening, and a substrate is not attached to the sheet, and a substrate is placed on the sheet corresponding to the opening. a storing step of storing the cleaning water; and Sheet a discharging step of scattering the cleaning water accumulated on top toward the inner wall of the cover, and a removing step of removing the cleaning water adhering to the inner wall of the cover by wind pressure caused by the rotation of the holding table after the discharging step is performed. The cleaning device includes a control unit for controlling at least the rotation of the holding table, and the control unit has a memory section for storing correlation data between the height at which the cleaning water collides with the inner wall of the cover in the discharging step and the rotation speed of the holding table, and the control unit controls the rotation speed of the holding table based on the correlation data in the discharging step so that the cleaning water collides with the inner wall at a desired height. , a method for cleaning the cover. In the cover cleaning method according to the present invention, it is preferable that the storing step, the releasing step, and the removing step are repeated a predetermined number of times. [Effects of the Invention]

[0008] A cleaning method according to the present invention for cleaning the inner wall of a cover of a cleaning apparatus including at least a holding table having a holding surface for holding substrates, a cleaning water supply nozzle for supplying cleaning water to the substrates held on the holding table, and a cover surrounding the outer periphery of the holding table includes a storing step in which cleaning water is supplied to the holding surface by the cleaning water supply nozzle to accumulate on the holding surface, a discharging step in which the holding table is rotated to spray the cleaning water accumulated on the holding table in the storing step toward the inner wall of the cover, and a removing step in which, after the discharging step, the cleaning water adhering to the inner wall of the cover is removed by the rotation of the holding table using wind pressure generated by the rotation. This method more effectively cleans and removes dirt from the inner wall of the cover. That is, unlike conventional methods, cleaning water is first accumulated on the holding surface of the holding table, and then, in the discharging step, the cleaning water is discharged radially outward as large droplets rather than as fine sprays due to the rotation of the holding table. This allows the large amount of droplet-like cleaning water to hit the inner wall of the cover, making it easier to remove (peel off) dirt from the inner wall. Then, in the removal step, the air pressure caused by the rotation of the holding table blows away and removes the cleaning water containing the dirt adhering to the inner wall, causing the dirt to flow down along with the cleaning water, leaving the inner wall free of dirt. The cleaning device also includes a control unit that controls at least the rotation of the holding table, and the control unit has a memory section that stores correlation data between the height at which the cleaning water collides with the inner wall of the cover in the release step and the rotation speed of the holding table.In the cover cleaning method of the present invention, the control unit controls the rotation speed of the holding table in the release step based on the correlation data, so that the cleaning water collides with the inner wall at a desired height, thereby enabling concentrated and effective cleaning of targeted dirty areas of the inner wall. For example, in the storage step, by holding a frame unit configured by adhering a sheet to a holding surface so as to cover the opening of a ring-shaped frame having an opening, it is possible to more efficiently store cleaning water on the sheet corresponding to the opening instead of on the holding surface. Furthermore, in the storage step, by holding a container having a convex portion on the outer periphery and a concave portion in the center surrounded by the convex portion on the holding surface of the holding table, it is possible to store cleaning water more efficiently in the concave portion instead of on the holding surface. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing an example of a cleaning device. [Figure 2] FIG. 10 is a cross-sectional view illustrating a state in which a storage step is being performed. [Figure 3] FIG. 10 is a cross-sectional view illustrating a state in which the releasing step is being performed. [Figure 4] 10 is an example of correlation data in a table format showing the correlation between the height at which the cleaning water hits the inner wall of the cover in the discharging step and the rotation speed of the holding table. [Figure 5] FIG. 10 is a cross-sectional view illustrating a state in which a removal step is being performed. [Figure 6] FIG. 1 is a perspective view showing an example of a container having a convex portion on the outer periphery and a concave portion in the center surrounded by the convex portion. DETAILED DESCRIPTION OF THE INVENTION

[0010] 1 is, for example, a single-wafer type cleaning apparatus that supplies cleaning water to a substrate 19 held on a holding table 30 to clean the substrate 19. Note that the cleaning apparatus 3 may be incorporated into a processing apparatus such as a grinding apparatus or a cutting apparatus, or may be used independently.

[0011] The substrate 19 shown in FIG. 1 is, for example, a circular plate-shaped silicon semiconductor wafer. On a surface 190 of the substrate 19 facing upward, devices 192 are formed in grid-like regions defined by planned division lines 191. For example, a back surface 193 of the substrate 19 is attached to the adhesive surface (front surface) of a sheet 198. The outer periphery of the sheet 198 is attached to an annular frame 197, whereby the substrate 19 is supported by the annular frame 197 via the sheet 198, forming a work set 199 that can be handled using the annular frame 197. The center of the annular frame 197 and the center of the substrate 19 are approximately aligned. Note that the substrate 19 is not limited to the above example and may be a substrate alone rather than a work set 199, or may be made of gallium arsenide, sapphire, gallium nitride, resin, ceramics, silicon carbide, or the like in addition to silicon. It may also be a substrate without devices formed thereon, or a package substrate, or the like.

[0012] The cleaning apparatus 3 shown in FIG. 1 includes, for example, a holding table 30 having a holding surface 302 for holding a substrate 19, a rotation mechanism 32 for rotating the holding table 30, a cylindrical cover 34 with a bottom and a circular opening on the upper end side, and a cleaning water supply nozzle 35 for supplying cleaning water to the substrate 19.

[0013] The holding table 30 has, for example, a circular outer shape and includes an adsorption unit 300 made of a porous material or the like that adsorbs the workpiece set 199, and a frame 301 that supports the adsorption unit 300. The adsorption unit 300 is connected to a suction source (not shown), and the suction force generated by the suction source is transmitted to a holding surface 302, which is the exposed surface of the adsorption unit 300 and is formed flush with the upper surface of the frame 301, allowing the holding table 30 to adsorb and hold the substrate 19 on the holding surface 302. Also, around the periphery of the frame 301, for example, four fixed clamps 304 that fix the annular frame 197 are evenly arranged. The fixed clamps 304 are, for example, pendulum-type fixed clamps. When the holding table 30 begins to rotate, the weights receive centrifugal force, causing the clamp plates to clamp the annular frame 197. Note that the fixed clamps 304 may also be spring-type mechanical clamps.

[0014] The rotation mechanism 32 disposed below the holding table 30 includes at least a spindle 320, the upper end of which is fixed to the bottom surface of the holding table 30 and rotatable about a vertical axis (Z-axis direction), and a rotation drive source 321, such as a motor, connected to the lower end of the spindle 320. When the rotation drive source 321 rotates the spindle 320, the holding table 30 fixed to the spindle 320 also rotates. The rotation drive source 321 is supported by an elevating unit 322, such as an air cylinder, so that the rotation drive source 321 can move up and down. The elevating unit 322 raises the rotation drive source 321 to raise the holding table 30 and position it at a height for loading and unloading the substrate 19, and lowers the rotation drive source 321 to lower the holding table 30 holding the substrate 19 and position it at a height for cleaning work within the cover 34.

[0015] The holding table 30 is housed in the internal space of a cover 34 that surrounds the outer periphery of the holding table 30. Note that in FIG. 1, a portion of the outer plate 340 of the cover 34 is cut away so that the interior can be seen. The cover 34 is composed of the outer plate 340 that surrounds the holding table 30, a bottom plate 341 that is integrally connected to the lower part of the outer plate 340 and has a central opening through which the spindle 320 is inserted, and an inner plate 342 that stands upright from the inner peripheral edge of the opening of the bottom plate 341. The cover 34 is supported by legs 343 that have one end fixed to the bottom plate 341. A discharge port 349 is formed through the bottom plate 341 in the thickness direction, and a hose 346 is connected to the discharge port 349 to discharge, to the outside of the cover 34, cleaning water containing dirt that has flowed from the holding surface 302 of the holding table 30 into the cover 34.

[0016] 1 and 2, a circular skirt cover 344 inserted onto the spindle 320 is disposed between the underside of the holding table 30 and the upper end surface of the inner plate 342 of the cover 34. When the holding table 30 is positioned at the working height within the cover 34, the skirt cover 344, which hangs down in the -Z direction from the outer periphery of the skirt cover 344, surrounds the periphery of the inner plate 342. The skirt cover 344 prevents cleaning water containing dirt flowing down from the holding surface 302 of the holding table 30 from entering the gap between the spindle 320 and the opening of the bottom plate 341.

[0017] As shown in FIG. 1 , a cleaning water supply nozzle 35 for spraying cleaning water onto the surface 190 of a substrate 19 held by suction on the holding surface 302 and an air injection nozzle 37 for spraying air onto the surface 190 of a substrate 19 held by suction on the holding surface 302 are disposed within the cover 34. The cleaning water supply nozzle 35 and the air injection nozzle 37 are erected, for example, from the bottom plate 341 of the cover 34 and have a generally L-shaped exterior when viewed from the side. The nozzles at their tips open toward the holding surface 302 of the holding table 30. Both nozzles are rotatable about their axes in the Z-axis direction, allowing their respective injection ports to be moved from above the holding table 30 to a retracted position. The cleaning water supply nozzle 35 is connected to a cleaning water supply source 350, such as a pump capable of delivering cleaning water, e.g., pure water. The air injection nozzle 37 is connected to an air supply source 370, such as a compressor capable of delivering compressed air.

[0018] 1, the cleaning device 3 includes a control unit 9 that controls at least the rotation of the holding table 30. The control unit 9 includes a CPU that performs calculations according to a control program, a storage unit 91 such as a memory, etc. The control unit 9 is electrically connected to a rotation drive source 321 that includes a motor or the like of the rotation mechanism 32 via, for example, a wired or wireless communication path. Rotational drive source 321 is, for example, a servo motor, and spindle 320 rotates when an operation signal is supplied to rotational drive source 321 from an output interface of control unit 9, which also functions as a servo amplifier, and the rotational speed of holding table 30 recognized by the encoder is output as an encoder signal to the input interface of control unit 9. Then, upon receiving the encoder signal, control unit 9 can perform feedback control to adjust the rotational speed of holding table 30 to a desired rotational speed.

[0019] The cleaning of the substrate 19 using the cleaning device 3 shown in FIG. 1 will be described below. The work set 199 is transported above the holding table 30 and placed on the holding surface 302 so that the center of the work set 199 roughly coincides with the center of the holding surface 302 of the holding table 30. A suction force generated by a suction source (not shown) is transmitted to the holding surface 302 of the holding table 30, causing the holding table 30 to hold the work set 199 by suction. Then, the holding table 30 that holds the work set 199 by suction is lowered by the lifting unit 322 to a cleaning operation height position (for example, the lowest height position) within the cover .

[0020] Next, the cleaning water supply nozzle 35 pivots, and the nozzle of the cleaning water supply nozzle 35 is positioned above the central region of the surface 190 of the substrate 19 held by suction on the holding table 30. Then, cleaning water (e.g., pure water) is sprayed from the nozzle of the cleaning water supply nozzle 35 toward the center of the surface 190 of the substrate 19. Furthermore, the cleaning water supply nozzle 35, which sprays the cleaning water, pivots so as to move back and forth at a predetermined angle around the axis in the Z-axis direction above the substrate 19. Furthermore, as the holding table 30 rotates at a predetermined rotational speed, cleaning water is sprayed from the cleaning water supply nozzle 35 onto the entire surface 190 of the substrate 19.

[0021] As a result, the substrate 19 is cleaned, and centrifugal force generated by the rotation of the holding table 30 causes the cleaning water to flow from the center toward the periphery over the surface 190 of the substrate 19, and then from above the holding table 30 down to the bottom plate 341 of the cover 34. After the substrate 19 has been cleaned with the cleaning water for a predetermined time, the spraying of the cleaning water from the cleaning water supply nozzle 35 is stopped. Next, air is sprayed from the nozzle of the air spray nozzle 37 toward the center of the surface 190 of the substrate 19. Furthermore, the air spray nozzle 37, which sprays air, revolves around the axis in the Z-axis direction above the substrate 19 at a predetermined angle, thereby drying the entire surface 190 of the substrate 19 with air. Then, when the drying of the substrate 19 is complete, the air spray nozzle 37 revolves and moves away from above the holding table 30, and the work set 199 is removed from the holding table 30.

[0022] As described above, for example, when cleaning multiple substrates 19 in succession, it is assumed that cleaning water containing dirt that is scattered by the rotation of the holding table 30, etc., adheres to the inner wall 348 of the outer plate 340 of the cover 34. Therefore, the operation of each component of the cleaning device 3 shown in FIG. 1 when cleaning the inner wall 348 of the cover 34 will be described below together with each step of the cleaning method according to the present invention.

[0023] (1) Storage step 2, in this embodiment, cleaning water is supplied by cleaning water supply nozzle 35 to frame unit 196 configured by adhering sheet 198 to holding surface 302 of holding table 30 so as to cover the opening of annular frame 197, and a storing step is performed in which cleaning water is stored on sheet 198 corresponding to the opening of annular frame 197. Note that cleaning water may be stored directly on holding surface 302 of holding table 30, but since holding surface 302 is not completely horizontal, there is a risk that cleaning water will run off and the capacity that can be stored is limited due to surface tension, so using frame unit 196 is preferable because it increases the amount of cleaning water that can be stored by annular frame 197.

[0024] The frame unit 196 is configured such that the substrate 19 of the work set 199 shown in FIG. 1 is not adhered to the sheet 198. The sheet 198 may be an adhesive tape with an adhesive layer. The sheet 198 may be, for example, a polyester-based resin sheet. The polyester-based sheet 198 is a polymer sheet synthesized using dicarboxylic acid (a compound having two carboxyl groups) and diol (a compound having two hydroxyl groups) as monomers. Because the polyester-based sheet 198 does not have an adhesive layer, it cannot be adhered to the annular frame 197 at room temperature. However, because the polyester-based sheet 198 has thermoplastic properties, when it is joined to the annular frame 197 while being pressed under a predetermined pressure and heated to a temperature near its melting point, it partially melts and can be adhered to the annular frame 197. The sheet 198 may be a polyolefin sheet or polystyrene sheet that does not have an adhesive layer but is heat-adhesive.

[0025] The frame unit 196 is placed on the holding surface 302 so that the center of the frame unit 196 roughly coincides with the center of the holding surface 302 of the holding table 30, and the holding table 30 holds the frame unit 196 by suction. Then, the holding table 30, which holds the frame unit 196 by suction, is lowered by the lifting unit 322 (not shown in FIG. 2) to, for example, the lowest height position within the cover 34.

[0026] The cleaning water supply nozzle 35 pivots and the nozzle of the cleaning water supply nozzle 35 is positioned above the central region of the opening of the frame unit 196 held by suction on the holding table 30. Then, cleaning water 356 is dripped from the nozzle of the cleaning water supply nozzle 35 onto the sheet 198 corresponding to the opening of the frame unit 196. The holding table 30 also rotates at a predetermined rotational speed. Note that the holding table 30 may be stationary and not rotate. The holding table 30 rotates at a speed slower than the rotation speed of the holding table 30 in the releasing step and removing step described below, and the rotation speed of the holding table 30 is controlled by the control unit 9 to a rotation speed that prevents the cleaning water 356 from being scattered by centrifugal force from the sheet 198 corresponding to the openings of the frame unit 196. In the storing step, the holding table 30 is rotated at such a slow speed in order to store the cleaning water 356 more evenly on the sheet 198 corresponding to the openings of the frame unit 196 that are sucked and held by the holding surface 302, since the holding surface 302 is not completely horizontal.

[0027] The storing step is completed when a predetermined amount of cleaning water 356 is stored on sheet 198 by the annular frame 197 and surface tension as a result of dropping cleaning water 356 onto sheet 198 from the nozzle of cleaning water supply nozzle 35 for a predetermined time. Note that even after the storing step is completed, cleaning water supply nozzle 35 continues to supply cleaning water 356 to sheet 198 on holding surface 302.

[0028] When cleaning water 356 is stored directly on the holding surface 302 without using the frame unit 196, the storing step is completed when cleaning water 356 is dripped onto the holding surface 302, which is rotating at a low speed, from the nozzle of the cleaning water supply nozzle 35 for a predetermined time, and a predetermined amount of cleaning water 356 is stored on the holding surface 302 due to surface tension. Note that even after the storing step is completed, the cleaning water supply nozzle 35 continues to supply cleaning water 356 to the holding surface 302.

[0029] (2) Release step 3, the rotation speed of the holding table 30 is made faster than that in the storing step under the control of the rotation mechanism 32 by the control unit 9. As a result, the cleaning water 356 that has accumulated on the sheet 198 of the frame unit 196 on the holding table 30 in the storing step is released as large droplets by centrifugal force toward the inner wall 348 of the outer plate 340 of the cover 34.

[0030] Conventionally, cleaning water supplied from a cleaning water supply nozzle collides with the holding surface of the holding table rotating at high speed, scattering and atomizing upon the collision, but in the cleaning method according to the present invention, cleaning water 356 that has accumulated on sheet 198 of frame unit 196 or on holding surface 302 of holding table 30 so as to form a water film is released by centrifugal force, so that instead of being atomized, the cleaning water 356 in the form of droplets with larger diameters and a larger amount of water than conventional droplets collides with inner wall 348. As a result, dirt such as processing debris adhering to inner wall 348 is subjected to the impact and peels off from inner wall 348, becoming included in cleaning water 356 adhering to inner wall 348. The cleaning water 356 continues to be supplied onto the sheet 198 from the cleaning water supply nozzle 35 even during the discharge step.

[0031] For example, the memory unit 91 of the control unit 9 pre-stores correlation data 99 shown in FIG. 4 , which correlates the height at which the cleaning water 356 strikes the inner wall 348 of the cover 34 during the discharge step with the rotational speed of the holding table 30. The correlation data 99 is data obtained experimentally, empirically, or theoretically from past experiments. While the correlation data 99 uses table-format data showing the correspondence between the rotational speed of the holding table 30 and the height at which the cleaning water 356 strikes, graph-format data may also be used. The correlation data 99 indirectly represents the height at which the cleaning water 356 strikes the inner wall 348 as an angle at which droplets of the cleaning water 356 are scattered diagonally upward, with the holding surface 302 as the 0-degree reference, but this is not limiting. Furthermore, even when the cleaning water 356 is stored on the sheet 198 of the frame unit 196, as in this embodiment, the correlation data 99 can be used as is. This is because the sheet 198 is very thin and its thickness can be ignored. Furthermore, when a thick sheet is used as the sheet 198, the angle obtained by adding the thickness of the sheet as a correction value to the above angle of the correlation data 99 may be recognized as the appropriate angle.

[0032] In the discharging step of this embodiment, the control unit 9 controls the rotation speed of the holding table 30 based on the correlation data 99 so that the cleaning water 356 discharged by centrifugal force collides with the inner wall 348 of the cover 34 at a desired height. That is, for example, as shown in the correlation data 99, when droplets of cleaning water 356 are to collide with the inner wall 348, which is particularly heavily soiled and at a height position where a virtual line L1 that is inclined 15 degrees diagonally upward from the holding surface 302 of the holding table 30 positioned at the lowest height position, collides with the holding surface 302, the holding table 30 being positioned at the lowest height position, the control unit 9 controls the rotation speed of the holding table 30 with reference to the correlation data 99, and sets the rotation speed of the holding table 30 to 1000 rpm. As a result, droplets of cleaning water 356 fly toward and collide with the inner wall 348 at a height position where a virtual line L1 that is inclined 15 degrees diagonally upward from the outer peripheral region of the sheet 198 corresponding to the opening of the annular frame 197 collides with the holding surface 302, which is positioned at a height position where the virtual line L1 is inclined 15 degrees diagonally upward from the outer peripheral region of the sheet 198 corresponding to the opening of the annular frame 197. Furthermore, if the holding table 30 is rotated at a slow speed, the droplets of cleaning water 356 can be caused to collide with the inner wall 348 at a lower height, and if the holding table 30 is rotated at a faster speed, the droplets of cleaning water 356 can be caused to collide with the inner wall 348 at a higher height.

[0033] As described above, by carrying out the release step for a predetermined period of time while controlling the rotation speed of the holding table 30, the cleaning water 356 that had accumulated on the sheet 198 of the frame unit 196 is eliminated, and the process shifts to cleaning the inner wall 348 with the cleaning water 356 that collides with the sheet 198 of the frame unit 196 held by suction on the holding table 30 and is atomized in the same manner as conventional, thereby completing the release step once.

[0034] (3) Removal step Next, after the discharge step is performed, a removal step is performed in which the cleaning water 356 containing dirt adhering to the inner wall 348 of the cover 34 is removed by rotating the holding table 30 and using the wind pressure generated by the rotation of the holding table 30. First, as shown in FIG. 5 , the supply of cleaning water 356 onto the sheet 198 by the cleaning water supply nozzle 35 is stopped. Then, for example, under rotation control by the control unit 9, the holding table 30 rotates at a speed even faster than the rotation speed in the discharging step, generating wind 308 blown from the holding table 30 toward the inner wall 348 of the cover 34. The wind pressure of the wind 308 sweeps the cleaning water 356 containing dirt adhering to the inner wall 348 away from the inner wall 348 and down to the bottom plate 341 of the cover 34. In other words, foreign matter and dirt that have separated from the inner wall 348 are swept away along with the cleaning water 356. It is preferable that the holding table 30 rotates at a high speed so that the wind 308 collides with the upper region of the inner wall 348 and flows along the inner wall 348 toward the bottom plate 341. The rotation speed of the holding table 30 in the removing step may be the same as or slower than that in the discharging step, provided that wind pressure is generated that can wash away the cleaning water adhering to the inner wall 348 of the cover .

[0035] As described above, the removal step is performed while rotating the holding table 30 at high speed for a predetermined time, and then the removal step is completed once. Even if one cycle of the storage step, release step, and removal step is completed, it may not be possible to completely remove all dirt from the inner wall 348. Therefore, it is preferable to repeat the storage step, release step, and removal step a predetermined number of times, for example.

[0036] As described above, the cleaning method of the present invention for cleaning the inner wall 348 of the cover 34 of the cleaning device 3 includes at least a holding table 30 having a holding surface 302 for holding a substrate 19, a cleaning water supply nozzle 35 for supplying cleaning water to the substrate 19 held on the holding table 30, and a cover 34 surrounding the outer periphery of the holding table 30. The cleaning method includes a storage step in which cleaning water 356 is supplied to the holding surface 302 by the cleaning water supply nozzle 35 to accumulate the cleaning water 356 on the holding surface 302, a discharge step in which the holding table 30 is rotated to spray the cleaning water 356 accumulated on the holding table 30 in the storage step toward the inner wall 348 of the cover 34, and a removal step in which, after the discharge step, the holding table 30 is rotated and the cleaning water 356 adhering to the inner wall 348 of the cover 34 is removed by the wind pressure caused by the rotation, thereby more effectively cleaning and removing dirt from the inner wall 348 of the cover 34. That is, unlike the conventional method, cleaning water 356 is first accumulated on holding surface 302 of holding table 30, and then in a discharging step, cleaning water 356 is discharged radially outward as large droplets rather than as fine sprays by the rotation of holding table 30, so that the droplets of cleaning water 356 hit the inner wall 348 of cover 34, making it easier to remove (separate) dirt from inner wall 348 more effectively. Then, in a removing step, wind pressure generated by the rotation of holding table 30 blows away and removes cleaning water 356 containing dirt adhering to inner wall 348, making it possible to make inner wall 348 free of dirt.

[0037] The cleaning device 3 also includes a control unit 9 that controls at least the rotation of the holding table 30, and the control unit 9 has a memory section 91 that stores correlation data 99 between the height at which the cleaning water 356 collides with the inner wall 348 of the cover 34 in the discharge step and the rotation speed of the holding table 30. In the method for cleaning the cover 34 according to the present invention, the control unit 9 controls the rotation speed of the holding table 30 in the discharge step based on the correlation data 99 so that the cleaning water 356 collides with the inner wall 348 at a desired height, thereby enabling the dirty areas of the inner wall 348 to be more effectively and concentratedly cleaned with the droplet-like cleaning water 356.

[0038] For example, as in this embodiment, in the storage step, by holding a frame unit 196 configured by adhering a sheet 198 to a holding surface 302 so as to cover the opening of a ring-shaped frame 197 having an opening, it is possible to more efficiently store cleaning water 356 on the sheet 198 corresponding to the opening instead of on the holding surface 302.

[0039] The steps of the cleaning method according to the present invention are not limited to the above-described embodiment, and may be implemented in various different forms within the scope of the technical concept. Furthermore, the configuration of the cleaning device 3 used may be changed as appropriate within the scope of the effects of the present invention.

[0040] For example, when carrying out the storage step, release step, and removal step, a container 4 having a convex portion 40 on the outer periphery and a concave portion 41 in the center surrounded by the convex portion 40 as shown in Figure 6, i.e., for example, a thin, circular, dish-shaped container 4 in a plan view, can be suction-held on the holding surface 302 of the holding table 30, so that the height of the convex portion can be formed to match the desired storage capacity, allowing cleaning water to be efficiently stored in the concave portion 41 during the storage step. In the storing step, the cleaning water supply nozzle 35 may be stationary and not swiveling, as long as cleaning water can be stored. In the discharging step, the cleaning water supply nozzle 35 may be stationary or swiveling, as long as cleaning water can be supplied from the cleaning water supply nozzle 35 onto the sheet 198 or the recess 41. [Explanation of symbols]

[0041] 19: Circuit board 199: Work set 196: Frame unit 3: Cleaning equipment 30: Holding table 302: Holding surface 304: Fixed clamp 32: Rotation mechanism 322: Lifting unit 34: Cover 35: Cleaning water supply nozzle 37: Air injection nozzle 9: Control unit 91: Memory unit 99: Correlation data

Claims

1. A cleaning method for cleaning an inner wall of a cover of a cleaning apparatus including at least a holding table having a holding surface for holding a substrate, a cleaning water supply nozzle for supplying cleaning water to the substrate held on the holding table, and a cover surrounding an outer periphery of the holding table, the method comprising: a retaining step of retaining a frame unit configured such that a sheet is adhered to the retaining surface of an annular frame having an opening so as to close the opening, and no substrate is attached to the sheet, and retaining the cleaning water on the sheet corresponding to the opening; a discharging step of scattering the cleaning water accumulated on the sheet in the storing step toward the inner wall of the cover while rotating the holding table; a removing step of removing the cleaning water attached to the inner wall of the cover by wind pressure caused by rotating the holding table after the discharging step is performed, the cleaning device includes a control unit for controlling rotation of at least the holding table; the control unit has a memory section that stores correlation data between a height at which the cleaning water hits the inner wall of the cover in the discharging step and a rotation speed of the holding table; a control unit for controlling the rotation speed of the holding table based on the correlation data in the discharging step so that the cleaning water impinges on the inner wall at a desired height.

2. 2. The method for cleaning a cover according to claim 1, wherein the storing step, the releasing step, and the removing step are repeated a predetermined number of times.

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