Cleaning device, method of operating the cleaning device, and program

Abstract

To improve the usability of the cleaning equipment. [Solution] The cleaning apparatus of the present disclosure comprises: a processing space forming unit that forms a processing space for cleaning a substrate; a brush having a sliding surface that slides relative to the substrate for cleaning the substrate in the processing space; and an imaging mechanism provided in a region separated from the processing space on one side of a transparent window, and equipped with a camera that images the sliding surface of the brush located on the other side of the window through the window.

Description

Technical Field

[0001] The present disclosure relates to a cleaning device, an operation method of the cleaning device, and a program.

Background Art

[0002] In the process of manufacturing a semiconductor device, a cleaning process using a brush may be performed on the front surface and / or the back surface of a substrate such as a semiconductor wafer (hereinafter referred to as a wafer). Patent Document 1 shows a device for performing a cleaning process on the back surface of a wafer using a brush.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technology that can improve the convenience of a cleaning device.

Means for Solving the Problems

[0005] The cleaning device of the present disclosure includes a processing space forming unit that forms a processing space for cleaning a substrate, a brush having a sliding surface that slides relative to the substrate for cleaning the substrate in the processing space, an imaging mechanism provided in a region partitioned from the processing space on one side of a transparent window and including a camera that images the sliding surface of the brush located on the other side of the window through the window, and includes.

Effects of the Invention

[0006] The present disclosure provides a technology that can improve the convenience of a cleaning device.

Brief Description of the Drawings

[0007] [Figure 1] This is a top view of a cleaning apparatus according to the first embodiment of this disclosure. [Figure 2] This is a longitudinal cross-sectional side view of the aforementioned cleaning device. [Figure 3] This is a perspective view of the brush provided in the cleaning device. [Figure 4] This is a perspective view of the imaging mechanism provided in the aforementioned cleaning device. [Figure 5] This is a side view of the components constituting the imaging mechanism and the brush. [Figure 6] This is a top view showing the brush being photographed. [Figure 7] This is a top view showing the polishing section provided on the brush. [Figure 8] This is a top view showing the cleaning apparatus during processing. [Figure 9] This is a side view showing the cleaning apparatus during processing. [Figure 10] This is a top view showing the cleaning apparatus during processing. [Figure 11] This is a side view showing the cleaning apparatus during processing. [Figure 12] This is a process diagram showing the procedure for imaging the brush. [Figure 13] This is a process diagram showing the procedure for imaging the brush. [Figure 14] This is a process diagram showing the procedure for imaging the brush. [Figure 15] This is a process diagram showing the procedure for imaging the brush. [Figure 16] This is a process diagram showing the procedure for imaging the brush. [Figure 17] This is a process diagram showing the procedure for imaging the brush. [Figure 18] This is a process diagram showing another example of the brush imaging procedure. [Figure 19] This is a side view showing another example of the imaging mechanism configuration. [Figure 20] This is a longitudinal cross-sectional side view of the cleaning apparatus according to the second embodiment. [Figure 21]It is a longitudinal side view of the imaging mechanism provided in the cleaning device. [Figure 22] It is a top view of the illumination provided in the imaging mechanism. [Figure 23] It is a side view of the brush provided in the cleaning device according to the third embodiment. [Figure 24] It is a plan view of the brush provided in the cleaning device according to the third embodiment.

Mode for Carrying Out the Invention

[0008] 〔First Embodiment〕 The cleaning device 1 which is the first embodiment of the present disclosure will be described while referring to the top view of FIG. 1 and the longitudinal side view of FIG. 2. The cleaning device 1 cleans the back surface (lower surface) of the wafer W which is a circular substrate by supplying a cleaning liquid and brushing. By changing the portion held on the back surface of the wafer W, the cleaning of the central portion and the cleaning of the peripheral side on the back surface are performed step by step. Hereinafter, unless otherwise specified, the central portion cleaning and the peripheral side cleaning refer to the central portion cleaning and the peripheral side cleaning on the back surface of the wafer W.

[0009] And regarding the cleaning device 1, it is possible to make a determination regarding the state of the brush 44 that performs the above-mentioned brushing from the image acquired by imaging with the camera 61 provided in the imaging mechanism 6. The control device 100 that makes this determination corresponds to the determination unit. The determination regarding the state of the brush 44 is specifically, for example, the determination regarding the presence or absence of detachment of the abrasive 46 which is a member constituting the brush 44, and the wear state of the abrasive 46 (that is, the determination regarding the life of the abrasive 46).

[0010] The configuration of the cleaning apparatus 1 will be described below in detail. The cleaning apparatus 1 comprises a base body 11, a spin chuck 13, a cup 31 that surrounds the wafer W for processing, a cleaning processing unit 4, a cleaning nozzle 37, and an imaging mechanism 6. In Figure 1, the X, Y, and Z directions are mutually orthogonal directions, with the X and Y directions being horizontal and the Z direction being vertical. In the following description, the Y direction will be considered the front-back direction. Note that the directions obtained by tilting the X and Y directions around the vertical axis are shown as the X' and Y' directions, respectively. The angle of this tilt is less than 90°, and the X' and Y' directions are mutually orthogonal. Figure 2 shows a cross-section along the YZ direction, but for the sake of illustration, the imaging mechanism 6 is shown as a side view in the X' direction.

[0011] The base body 11 has a wide recess 12 in the Y direction when viewed from the side. The base body 11 is equipped with a horizontal partition plate 10 that closes the opening of this recess 12 from above. The partition plate 10 has an opening 19 on its front side. A spin chuck 13 is provided in the area that overlaps with the opening 19 when viewed from above. The spin chuck 13 holds the wafer W horizontally by adsorbing the central part of the back surface of the wafer W during peripheral cleaning. The spin chuck 13 is connected to a rotation mechanism 15 via a vertically extending shaft 14, and rotates around a vertical axis by the rotation mechanism 15.

[0012] Three support pins 16 are arranged to extend vertically around the shaft 14. The lower ends of the support pins 16 are connected to a lifting mechanism 17. The lifting mechanism 17 allows the support pins 16 to move vertically up and down, enabling the transfer of wafers W between a wafer transport mechanism (not shown), a spin chuck 13, and a suction unit 36 ​​(described later).

[0013] Furthermore, a cylindrical portion 21 is provided that extends vertically upward from the bottom of the base body 11, surrounding the shaft 14 and the support pin 16. The upper end surface of the cylindrical portion 21 forms an inclined surface 22 that slopes inward, and the upper end of this inclined surface 22 is close to the lower surface of the wafer W held by the spin chuck 13. Gas outlets 23 are provided on the inclined surface 22 at intervals in the circumferential direction of the cylindrical portion 21. During peripheral cleaning, gas is discharged from the outlets 23 to prevent the cleaning liquid from adhering to the central part of the wafer W.

[0014] A circular cover 24 is provided that extends from the outer circumferential surface of the cylindrical portion 21 outwards, with its peripheral end bent downwards. At the bottom of the recess 12 formed by the base body 11, an upright exhaust pipe 25 is provided, whose upper end is covered by this cover 24, to exhaust the inside of the recess 12 and the processing space 30 described later during the processing of the wafer W. In addition, a drain port 26 is opened at the bottom of the recess 12 of the base body 11.

[0015] Next, let's describe the cup 31. The cup 31 is made up of a bottomless, flat cylindrical member, and the upper end of the cup 31 forms an annular upper wall 32 that protrudes inward from the cup 31. The space enclosed by the cup 31 and partitioned from the surroundings is called the processing space 30, and the aforementioned cylindrical part 21 is contained within the processing space 30 when viewed from above. During central cleaning and peripheral cleaning, the wafer W is located in the processing space 30, and the cup 31 prevents the cleaning liquid from splashing into the surroundings.

[0016] Support arms 33 extend from the sides of the outer circumferential surface of the cup 31 to the left and right, respectively, and each support arm 33 is connected to a moving mechanism 34. The moving mechanism 34 allows the cup 31 to move horizontally in the front-rear direction and vertically up and down. When cleaning the peripheral side of the cup 31, it is positioned in the lowered position shown by the solid line in Figure 2, and when cleaning the central part, it is positioned in the raised position shown by the dashed line in Figure 2. In the raised position, it moves in the front-rear direction for processing the wafer W. During this front-rear movement, the lower end of the cup 31 is positioned above the partition plate 10 so as not to interfere with the partition plate 10. Furthermore, the up and down movement of the cup 31 is performed at a position where the cup 31 overlaps with the opening 19 provided in the partition plate 10 when viewed from above (the position shown in Figures 1 and 2), so as not to interfere with the partition plate 10.

[0017] Inside the cup 31, two bridge portions 35 are provided so as to sandwich the spin chuck 13 from the left and right, and each bridge portion 35 extends in the front-rear direction and is connected to the inner circumferential surface of the cup 31. Each bridge portion 35 is provided with a suction portion 36. Therefore, the suction portion 36 moves together with the cup 31. During central cleaning, the suction portion 36 attracts the wafer W at positions on the back surface that are separated from the center to the left and right, and the wafer W is held horizontally.

[0018] In a top view, a cleaning nozzle 37 is provided at a position overlapping the opening 19 of the partition plate 10. This cleaning nozzle 37 is positioned to discharge cleaning liquid to the center of the back surface of the wafer W during central cleaning, and to the peripheral surface of the back surface of the wafer W during peripheral cleaning. A cleaning liquid supply unit 38, including a valve, is provided to switch the supply of cleaning liquid from a cleaning liquid supply source (not shown) to the cleaning nozzle 37. The operation of this cleaning liquid supply unit 38 supplies, for example, pure water as the cleaning liquid to the cleaning nozzle 37.

[0019] Furthermore, a cleaning unit 4 is provided on the rear side of the cylindrical portion 21 within the recess 12. The cleaning unit 4 consists of an arm 41, a moving mechanism 42, a rotating mechanism 43, and a brush 44. The moving mechanism 42 is connected to the base end of the horizontally extending arm 41, and the arm 41 can be raised and lowered along the vertical direction by the moving mechanism 42. The tip of the arm 41 also rotates relative to the base end with the vertical axis as the pivot axis by the moving mechanism 42. The rotating mechanism 43 is provided on the tip of the arm, and a brush 44, which is circular in top view, is connected to the rotating mechanism 43, and the brush 44 rotates by the rotating mechanism 43. The rotation axis P of the brush 44 extends in the vertical direction and passes through the center of the brush 44 in top view.

[0020] Referring to the perspective view in Figure 3, the configuration of the brush 44 will be described. This brush 44 consists of a horizontal disc-shaped base 45 and a plurality of abrasive materials 46 provided on the upper surface of the base 45. Multiple through holes 45A for drainage are provided near the center of the base 45. The abrasive materials 46 are formed in a block shape that forms an arc when viewed from above. Each abrasive material 46 is arranged along the periphery of the base 45, and gaps 47 are formed between adjacent abrasive materials 46. Therefore, when multiple abrasive materials 46 are viewed together, they form a ring structure that is interrupted in multiple places. Each abrasive material 46 is detachable from the base 45 and is replaced when wear progresses.

[0021] The abrasive material 46 is mounted on the base 45 so that its upper surface is horizontal. A groove 49 is formed on the upper surface of the abrasive material 46, extending along the diameter of the brush 44 so as to bisect the upper surface in the circumferential direction of the brush 44. The upper surface, thus bisected by the groove 49, forms a sliding surface 48 that contacts and slides against the wafer W during cleaning. The abrasive material 46 has two protrusions 40 at its top, which are formed by the sliding surface 48, and when the abrasive material 46 is lined up on the base 45, these protrusions 40 are aligned laterally.

[0022] In the top views, such as Figure 1 and Figure 6 described later, the groove 49 is shown with a dotted line to distinguish it from the gap 47. The groove 49 has a lower brightness in the image than the sliding surface 48, and as the sliding surface 48 wears down, the groove 49 becomes shallower, causing its brightness to increase. Therefore, it is provided as a detection unit for detecting the state of wear. To briefly explain this, as it will be explained in detail later, the brightness of the groove 49 is obtained from the image as the brightness corresponding to the protrusion 40, and this brightness is used to determine the wear state of the abrasive material 46.

[0023] As described above, the brush 44 is subjected to alternating clockwise and counterclockwise rotation by the moving mechanism 42, resulting in oscillation when viewed from above, rotation of the brush 44 by the rotating mechanism 43, and rotation of the wafer W, which enables relative sliding between the sliding surface 48 and the back surface of the wafer W. More specifically, oscillation or rotation of the wafer W occurs while the brush 44 is rotating. This relative sliding occurs at the point where cleaning fluid is supplied to the back surface of the wafer W, and the cleaning process is performed.

[0024] Returning to Figures 1 and 2, the partition plate 10 of the base body 11 will be explained in more detail. The area above the partition plate 10, which is located behind the cup 31 that is at the rearmost position for central processing, is designated as the imaging area 18. The area below the partition plate 10 is connected to the processing space 30 inside the cup 31, for example, and gas (air) containing the cleaning solution flows in more easily from the processing space 30 than from the area above the partition plate 10. Therefore, the imaging area 18 is an area partitioned from the processing space 30 inside the cup 31. In other words, the imaging area 18 is partitioned from the processing space 30 inside the cup 31 by the partition plate 10. Note that the partition plate 10 is not limited to the shape shown in Figures 1 and 2, but can have various shapes as long as it partitions its upper area and the lower area which is connected to the inside of the cup 31 below it. A circular through-hole is provided in the partition plate 10 so as to face this imaging area 18. Furthermore, an annular window frame 51 is provided on the opening edge of this through hole, along the opening edge, so as not to interfere with the cup 31 that moves to the rear. A disc-shaped window 52 is horizontally positioned, supported by the window frame 51, and closes the opening formed by the window frame 51.

[0025] The window 52 is transparent, and the brush 44 located at the imaging position on the lower side (other side) of the window 52 can be imaged by the imaging mechanism 6 provided on the upper side (one side) of the window 52, ​​as will be described later. The window frame 51 is made of metal and is connected to the ground potential via a conductive path (not shown), and the window 52 is discharged via the window frame 51 and the conductive path.

[0026] The side view of the brush 44 at the imaging position is shown by a dashed line in Figure 2. The side view of the brush 44 at the imaging position is also shown in Figure 4. At the imaging position, the sliding surface 48 of the brush 44 is close to the lower surface of the window 52. In order to prevent the moisturizing liquid remaining on the abrasive material 46 from affecting the imaging, as will be described in detail later, the imaging position is set such that the height H1 (see Figure 4) of the gap between the sliding surface 48 and the lower surface of the window 52 is, for example, 1 mm or less, and more specifically, in the range of 10 μm to 1 mm. As the imaging position is set in this manner, this imaging position is located behind (i.e., laterally) from the processing space 30 in the cup 31 where the brush 44 is located during the processing of the wafer W.

[0027] The area below the imaging position is a standby position where the brush 44 is kept in standby mode when wafer W is not being processed or imaged. This standby position is indicated by a dashed line in Figure 2. Therefore, the brush 44 is imaged when it is raised above the standby position and in close proximity to the window 52 (raised state).

[0028] In order to moisten the abrasive material 46 of the brush 44 in the standby position so that it can be processed quickly on the wafer W, a moisturizing nozzle 53 is provided for dispensing moisturizing liquid onto the abrasive material 46. A moisturizing liquid supply unit 54, including a valve, is provided to switch the supply of moisturizing liquid from a moisturizing liquid supply source (not shown) to the moisturizing nozzle 53, and the operation of the moisturizing liquid supply unit 54 supplies moisturizing liquid, such as pure water, to the moisturizing nozzle 53. In the standby position, the brush 44 is rotated by a rotation mechanism 43 so that moisturizing liquid is supplied to all of the abrasive material 46.

[0029] Next, the imaging mechanism 6 will be explained with reference to Figure 5, which is a perspective view. The imaging mechanism 6 includes a camera 61, illumination 62, a mirror 63, and a support 64, and is installed in the imaging area 18 on the window 52 and partition plate 10. In the following explanation, one side and the other side in the Y' direction will be referred to as the +Y' side and the -Y' side, respectively. The +Y' side faces forward, and the -Y' side faces backward.

[0030] The support section 64 comprises a horizontal section 65, an upright section 66, and a lighting support section 67. The horizontal section 65 and the upright section 66 are formed, for example, by bending both ends of a single horizontal plate upward. The -Y' end of the horizontal section 65 is supported above the partition plate 10 by a base 68 provided on the partition plate 10. The upright section 66 has a portion that protrudes from the horizontal section 65 towards the +Y' side, and this portion supports the mirror 63 above the window 52. The mirror 63 is plate-shaped, with one of the two main surfaces of the plate forming a reflective surface 63A, which is oriented towards the -Y' side. The mirror 63 is tilted so that the upper side of the reflective surface 63A is located towards the -Y' side more than the lower side. Later, the height relationship between the mirror 63 and the other components will be explained, but unless otherwise specified, the height of the mirror 63 in the explanation refers to the height of the reflective surface 63A, which is the actual part of the mirror 63.

[0031] A camera 61 is positioned on the horizontal portion 65 of the support portion 64, and is located at the same height as the upper side of the mirror 63. The field of view of the camera 61 is oriented in the +Y' direction so that it can capture the reflective surface 63A of the mirror 63. More specifically, the optical axis of the lens provided on the camera 61 is aligned with the Y' direction.

[0032] Furthermore, by being positioned on the horizontal section 65, the camera 61 is surrounded below and to the sides by the horizontal section 65 and the upright section 66. This surrounding prevents unwanted light other than the light from the mirror 63 (described later) from entering the camera 61, resulting in clearer images.

[0033] A plate-shaped lighting support 67 is provided extending from the lower surface of the horizontal section 65, and the lighting 62 is supported by this lighting support 67. Therefore, the height at which the lighting 62 is installed is different from the height at which the camera 61 is installed. More specifically, the height at which the lighting 62 is installed overlaps with the lower height of the height at which the mirror 63 is installed. The lighting 62 emits light toward the +Y' direction. As will be described in detail later, the optical axis L1 of the emitted light is along the Y direction. Therefore, the light from the lighting 62 shines on the reflective surface 63A of the mirror 63.

[0034] Furthermore, the illumination 62 is positioned away from the +Y' end of the horizontal section 65 toward the -Y' side, and is located on the +Y side (i.e., closer to the mirror 63) than the camera 61. The light spreading upward from the illumination 62 is blocked by the horizontal section 65. Therefore, this arrangement of the illumination 62 reliably prevents the light from bending around and entering the camera 61, resulting in clearer images.

[0035] Light emitted from the illumination 62 is reflected by the reflective surface 63A of the mirror 63, passes through the window 52, ​​and shines downwards on the window 52, ​​illuminating the upper surface of the brush 44 at the imaging position. The image of the upper surface of the brush 44 illuminated by the light (i.e., the image including the sliding surface 48 and grooves 49 of the abrasive material 46) is reflected by the mirror 63 and directed toward the camera 61, so that the image of the upper surface is captured by the camera 61. As a result, the camera 61 acquires image data of the upper surface of the brush 44. The camera 61 transmits this image data to the control device 100, which will be described later, and the control device 100 makes a determination regarding the state of the brush 44 based on the sliding surface 48 and grooves 49 in this image.

[0036] In a top view, the processing space 30 inside the cup 31 is located in front of the mirror 63, and the reflective surface 63A of the mirror 63 is oriented in the -Y direction, i.e., towards the rear, so as to face the camera 61. Thus, in a top view, the side on which the cup 31 is located relative to the mirror 63 is opposite to the side on which the mirror 63 reflects an image toward the camera 61. With this arrangement, even if mist of the cleaning solution is scattered from the processing space 30 inside the cup 31 to the outside of the cup 31 during processing of the wafer W, the mist is prevented from adhering to the reflective surface 63A of the mirror 63, thereby preventing malfunctions in the imaging of the brush 44.

[0037] Furthermore, as shown in Figure 2, the camera 61, illumination 62, and mirror 63 are positioned higher than the processing space 30 in both the raised and lowered positions (i.e., higher than the upper edge of the cup 31) by the support portion 64. Therefore, even if mist of the cleaning solution is scattered from the processing space 30 due to the processing of the wafer W, the adhesion of the mist to the camera 61, illumination 62, and mirror 63 is suppressed, thereby preventing malfunctions in the imaging of the brush 44.

[0038] Furthermore, only when the cup 31 is in the lowered position (out of the raised and lowered positions), the camera 61, illumination 62, and mirror 63 may all be positioned above the upper edge of the cup 31. In other words, when the cup 31 is in the raised position, the height regions of the illumination 62 and mirror 63 may overlap with the height region of the upper edge of the cup 31. However, as shown in Figure 2, it is more preferable to position the camera 61, illumination 62, and mirror 63 above the upper edge of the cup 31 in both the lowered and raised positions to suppress mist adhesion to these components and prevent imaging malfunctions.

[0039] Incidentally, it is conceivable to configure the imaging mechanism by placing the camera 61 above the window 52 without providing the mirror 63, and directing the camera 61's field of view downwards to image the brush 44. While such an imaging mechanism is possible, if the focal length of the camera 61 is relatively long, the camera 61 will be placed at a relatively large distance from the window 52, ​​which may result in the cleaning device 1 becoming relatively tall.

[0040] The imaging mechanism 6 is configured to image the brush 44 reflected in the mirror 63 from the side of the mirror 63, with the camera 61 positioned at the same height as the upper part of the height where the mirror 63 is located. Furthermore, to use the mirror 63 to illuminate the window 52 with light from the illumination 62, the illumination 62 is positioned at the same height as the lower part of the mirror 63. By using the mirror 63 in this way, the camera 61's field of view is directed to the side, and the camera 61 and illumination 62 are positioned in parts of the height region where the mirror 63 is located, respectively, thus reducing the height occupied by the imaging mechanism 6. Therefore, this configuration of the imaging mechanism 6 reduces the height of the cleaning device 1, preventing it from becoming oversized.

[0041] Furthermore, by positioning the lighting 62 in a portion of the height range in which the mirror 63 is arranged, the lighting 62 is positioned above the window 52, ​​and the direction of light irradiation from the lighting 62 is in the lateral direction (in this example, the horizontal direction, which is the +Y′ direction) along the sliding surface 48 of the brush 44. In other words, positioning the lighting 62 above the window 52 and directing the light irradiation along the sliding surface 48 also contributes to keeping the height of the cleaning device 1 down.

[0042] The positional relationship between the illumination 62, the mirror 63, and the brush 44 at the imaging position will be explained with reference to Figure 4 and Figure 6, which is a top view of the brush 44 and the window 52. Figure 6 is also a schematic diagram representing the image acquired by the camera 61. The optical axis of the light emitted from the illumination 62 is denoted as L1 and is shown by the dashed arrow in Figure 4. The optical axis L1 is a line that continuously connects the points where the light intensity is greatest at each part in the optical path direction (i.e., the center of the light) for the emitted light. Of this optical axis L1, the part from the illumination 62 to the mirror 63 is directed in the horizontal direction, +Y′, as mentioned above. For the sake of explanation, if we define the path of the optical axis L1 that is reflected by the mirror 63 and directed downwards as the illumination axis L0, then the position and orientation of the mirror 63 are set so that the illumination axis L0 is tilted at an acute angle with respect to the vertical direction.

[0043] Therefore, if we define A1 as the direction perpendicular to the horizontal sliding surface 48 of the brush 44, then in a side view, the illumination axis L0 is tilted to make an acute angle θ with respect to direction A1. This tilt causes the illumination axis L0 to pass to the side of the brush 44 at the imaging position. More specifically, in a top view, the illumination axis L0 passes at a position away from the rotation axis P of the brush 44 on the +Y' side in the Y' direction. Therefore, the illumination axis L0 is off-center from each sliding surface 48. In other words, the illumination axis L0 does not intersect with any of the sliding surfaces 48. Note that the direction A1 perpendicular to the sliding surface 48 is also the depth direction of the groove 49, and in this example, it is also the vertical direction (Z direction).

[0044] If the mirror 63 is positioned so that the illumination axis L0 is parallel to direction A1, shadows will be less likely to be cast on the upper surface of the abrasive material 46 by the walls forming the grooves 49, and relatively strong light will be reflected from the grooves 49 and the sliding surface 48 in a similar or approximately similar manner. As a result, the brightness of the sliding surface 48 in the acquired image may become too high, making it difficult to pinpoint the position of the sliding surface 48, or making it difficult to distinguish between the sliding surface 48 and the grooves 49 in the image, or making it difficult to observe changes in the brightness of the grooves 49 due to changes in the depth of the grooves 49. In other words, it may become difficult to make a determination regarding the brush 44.

[0045] However, as shown in Figure 4, by tilting the irradiation axis L0 with respect to direction A1, the intensity of reflected light at the sliding surface 48 and the groove 49 is suppressed. In addition, the walls forming the groove 49 cast a shadow on the upper surface of the abrasive material 46, and the sliding surface 48 and the groove 49 are clearly distinguished by the difference in brightness. Therefore, the occurrence of the above-mentioned problems is suppressed, making it possible to make more reliable judgments regarding the brush 44 or to improve the accuracy of such judgments. Note that tilting the irradiation axis L0 with respect to direction A1 does not mean that it is inevitably tilted due to the limitations of the manufacturing technology of the device, but rather that it is tilted by design, and specifically, the angle θ is set to 5° or more.

[0046] Furthermore, by tilting the irradiation axis L0 with respect to direction A1 in this manner, the irradiation axis L0 is prevented from intersecting each abrasive material 46 as described above, thereby suppressing the generation of relatively strong reflected light from the sliding surface 48 and groove 49 of each abrasive material 46. Consequently, the positional relationship between the irradiation axis L0 and each abrasive material 46 is set in this manner, allowing for more reliable identification of the sliding surface 48 and groove 49, thereby improving the accuracy of the determination.

[0047] However, as described above, since the irradiation axis L0 passes through the +Y' side of the brush 44 at the imaging position, the brightness of the +Y' end region of the brush 44 in the image may become too high, making it difficult to identify the sliding surface 48 and groove 49 in that region. On the other hand, the brightness of the -Y' end region of the brush 44 in the image may become too low, making it difficult to identify the sliding surface 48 and groove 49 in that region. Therefore, of the acquired image, only the abrasive material 46 that is captured in the inspection region L2 located to the left and right of the straight line passing through the rotation axis P of the brush 44 and the irradiation axis L0 in a top view, excluding the -Y' and +Y' ends of the brush 44, is to be judged.

[0048] Each inspection area L2 is configured such that multiple abrasive materials 46 are contained within a single inspection area L2. When the brush 44 is rotated 90°, all abrasive materials 46 are positioned within the inspection area L2 either before or after the rotation. In other words, the inspection area L2 is configured such that all abrasive materials 46 can be contained within the inspection area L2 by rotating the brush 90°.

[0049] The cleaning apparatus 1 described above is equipped with a control unit, which is a control device 100 (see Figure 1). The control device 100 is, for example, a computer and has a program storage unit (not shown). The program storage unit stores a program that controls the processing of wafers W in the cleaning apparatus 1. The program storage unit also stores a program that controls the operation of the drive system described above to realize wafer processing in the cleaning apparatus 1. The program consists of a set of steps necessary to transport and process wafers W in the cleaning apparatus 1, and the control device 100 outputs control signals to each part of the cleaning apparatus 1 according to the program, thereby controlling each part as described above to perform the transport and processing. The control device 100 also performs calculations and judgments as described later, and if it determines that an abnormality has occurred, it outputs an alarm to that effect via sound or screen display.

[0050] The above program may be recorded on a computer-readable storage medium H and installed from said storage medium H to the control device 100. The storage medium H may include ROM, RAM, or a hard disk, but its structure and type are not limited, and it may be temporary or non-temporary. The control device 100 may include a part that stores, reads, and executes the program for realizing wafer processing and performs related communications, and the location of each part may be either inside or outside the cleaning apparatus 1. The control device 100 may be one or more circuits, and may be provided as a single unit or in separate parts.

[0051] To briefly describe the process by which the control device 100 determines the state of the brush 44, the control device 100 obtains a representative value of brightness from the sliding surface 48 or groove 49 that make up the upper surface of each abrasive material 46 from the image. The representative value may be the brightness at a predetermined position or the average value of the brightness at multiple predetermined positions. Then, the wear state is determined by comparing this representative value or a value calculated based on the representative value with a threshold value. In the following explanation, an example in which the representative value is the average value obtained from multiple positions in the groove 49 will be explained with reference to Figure 7, which is a top view of the abrasive material 46.

[0052] In Figure 7, the two edges of the groove 49 along the extension direction are shown as L3. The control device 100 identifies the position of the sliding surface 48 of each abrasive material 46 based on the brightness in the inspection area L2 in the image acquired by the camera 61. Furthermore, it identifies the position of the groove 49 on that sliding surface 48. Note that the position of the groove 49 may be identified based on the brightness in the image, or it may be identified based on the position of the sliding surface 48, since the groove 49 is formed at a specific position on the sliding surface 48.

[0053] Then, the average value of the brightness at each position on the edge L3 of the groove 49 (hereinafter referred to as the individual average brightness) is calculated. The individual average brightness is calculated for each abrasive material 46 included in the inspection area L2. As described above, all abrasive materials 46 can be captured by the camera 61 by the rotation of the brush 44, so the individual average brightness is obtained from all abrasive materials 46.

[0054] As the abrasive material 46 wears down, the depth of the groove 49 changes, and the brightness of each part of the groove 49, including the edge L3, becomes a value corresponding to that depth. Therefore, the wear state can be determined based on the above-mentioned individual average brightness. However, the brightness in the groove 49 may also change due to factors other than wear, such as liquid droplets, as described later, so the wear state is determined after removing abnormal values ​​(outliers) from this individual average brightness to improve the accuracy of the determination. Note that the brightness in the groove 49 and the individual average brightness calculated from the brightness in the groove 49 change depending on the wear state of the sliding surface 48 that forms the protrusion 40, as described above, and therefore correspond to the brightness of the protrusion 40.

[0055] Specifically, outliers are identified by applying the individual average brightness values ​​obtained from each abrasive material 46 to a pre-set calculation formula. That is, the brightness values ​​corresponding to the protrusions 40 that meet the pre-set abnormal conditions are identified. For example, the calculation formula can be set so that individual average brightness values ​​outside the range of Q1 - 1.5 × IQR to Q3 + 1.5 × IQR are considered outliers. IQR is the interquartile range, Q1 is the first quartile, and Q3 is the third quartile.

[0056] After identifying outliers, the control device 100 determines the wear state of the abrasive material 46 from the individual average brightness values ​​excluding these outliers. For example, it may compare the highest value among the individual average brightness values ​​excluding outliers with a preset threshold and determine whether the wear state is within an acceptable range based on the comparison result, or it may calculate the average value of the individual average brightness values ​​excluding outliers (which is the overall average value) and compare this overall average value with the threshold value to determine whether the wear state is within an acceptable range. In other words, the determination is made by comparing the representative brightness value (individual average brightness) or a value calculated based on the representative value (overall average value) with the threshold value.

[0057] If the wear condition is determined to be outside the acceptable range, an alarm is output to that effect. Also, for example, if there is a part of the abrasive material 46 whose position cannot be identified in the image during the process of determining the wear condition of the abrasive material 46, the control device 100 determines that an abnormality has occurred in which the abrasive material 46 has detached from the base 45, and outputs an alarm to that effect.

[0058] In the example described in Figure 7, the representative value of luminance obtained from the image and compared with a threshold was the average value at multiple predetermined positions in the groove 49. However, it may also be the luminance obtained from a predetermined position in the groove 49 (i.e., the luminance at a specific position in the groove 49). Furthermore, this representative value for luminance may be obtained from the sliding surface 48. That is, the representative value may be the luminance at a predetermined position on the sliding surface 48, or the average value of the luminance at multiple predetermined positions. As the abrasive material 46 wears down, the height H1 (see Figure 4) of the gap between the sliding surface 48 of the brush 44 and the lower surface of the window 52 at the imaging position increases, and this increase in height H1 may change the luminance in the image. When the luminance of the sliding surface 48 is used for determination in this way, the luminance of the sliding surface 48 or the luminance calculated from the luminance of the sliding surface 48 is the luminance corresponding to the protrusion 40, instead of the luminance of the groove 49 or the luminance calculated from the luminance of the groove 49 as described above.

[0059] Thus, since the position for obtaining a representative value of brightness does not have to be within the groove 49, the abrasive material 46 may be configured without grooves 49. However, in order to detect the wear state with high accuracy, it is preferable to provide grooves 49 in the abrasive material 46 as described above so that the wear state is clearly reflected as a change in brightness, and to make a determination based on the brightness within the grooves 49.

[0060] Next, the processing of the wafer W in the cleaning apparatus 1 will be explained. This will be explained with reference to Figures 8 to 11. Figures 8 and 9 show the top and side views of the wafer W and cup 31 during central cleaning, and Figures 10 and 11 show the top and side views of the wafer W and cup 31 during peripheral cleaning. The conveying mechanism conveys the wafer W above the cup 31, which is in a vertically movable position. The wafer W is then placed in the processing space 30 inside the cup 31 via the support pins 16, and its back surface is held by the suction part 36 of the cup 31, which has moved to the raised position. The brush 44 then moves from the standby position below the center of the wafer W, and the sliding surface 48 is pressed against the center of the back surface of the wafer W.

[0061] As the cup 31 moves backward, cleaning liquid R1 is discharged from the cleaning nozzle 37 to the center of the back surface of the wafer W. Then, the brush 44 is oscillated by the moving mechanism 42 and rotated by the rotating mechanism 43. As a result, the back surface of the wafer W, which moves together with the cup 31, is cleaned in the center, as shown in Figures 8 and 9.

[0062] When a predetermined area of ​​the wafer W is cleaned by the movement of the cup 31, the oscillation and rotation of the brush 44 and the discharge of the cleaning liquid R1 stop, and the brush 44 descends and moves away from the wafer W, completing the cleaning of the central part. After that, the cup 31 moves forward and returns to its vertically movable position. The wafer W is transferred from the suction part 36 to the spin chuck 13 via the support pin 16, and the central part of the back surface of the wafer W is attracted to the spin chuck 13. Then the brush 44 rises, and the sliding surface 48 is pressed against the peripheral edge of the back surface of the wafer W.

[0063] While cleaning liquid R1 is discharged from the cleaning nozzle 37 to the periphery of the wafer W, the spin chuck 13 rotates. At the same time, the brush 44 is rotated by the rotation mechanism 43, and peripheral cleaning is performed as shown in Figures 10 and 11. After that, the discharge of cleaning liquid R1 and the rotation of the brush 44 stop, and peripheral cleaning on the back surface of the wafer W is completed. Through the above cleaning of the central part and peripheral part, the entire back surface of the wafer W is cleaned except for the edges. After that, the brush 44 descends and moves away from the wafer W and returns to the standby position, and the wafer W is handed over to the transport mechanism by the support pin 16 and transported out of the cleaning device 1.

[0064] Next, referring to the process diagrams showing the sides of the brush 44 and the imaging mechanism 6 in Figures 12 to 17, the procedure for imaging and determining the brush 44 will be explained. As shown in Figure 12, the brush 44 waits in a standby position, rotated by the rotation mechanism 43. Moisturizing liquid R2 is supplied to the brush 44 in this standby position from the moisturizing nozzle 53. While the brush is in standby, if predetermined conditions are met, such as the wafer W not being transported to the cleaning apparatus 1 for a certain period of time, the discharge of cleaning liquid R1 from the cleaning nozzle 37 stops, the rotation of the brush 44 stops, and the brush 44 rises towards the imaging position for imaging (Figure 13). At this time of rising, the explanation will continue assuming that droplets R3 of moisturizing liquid R2 remain on the abrasive material 46.

[0065] As shown in Figure 4, the imaging position (the position where the brush 44 is in the raised position) is where the sliding surface 48 is close to the window 52. Therefore, the droplet R3 is pressed against the window 52, ​​forming a relatively thin liquid film, or it is scattered by impact with the window 52 and removed from the sliding surface 48 (Figure 14). Subsequently, as explained in Figure 4, the first image is taken by the camera 61 with light illuminating from the illumination 62, and image data V1 of the upper surface of the brush 44 shown in Figure 6 is transmitted to the control device 100 (Figure 15). The dashed arrows in Figure 15 indicate the light coming from the upper surface of the brush 44.

[0066] Next, the brush 44 lowers slightly and rotates 90° by the rotation mechanism 43 to change direction (Figure 16). The reason for rotating the brush 44 in this lowered position is to reliably prevent damage to the window 52 by the rotating brush 44. The height at which the brush 44 rotates in this manner is above the standby position.

[0067] The brush 44, having rotated 90° to change its orientation, rises and returns to the imaging position (Figure 17). Subsequently, similar to the first imaging shown in Figure 15, the camera 61 takes a second image with light illuminating it from the illumination 62, and the control device 100 acquires image data V2 of the upper surface of the brush 44. That is, the camera 61 takes another image in the state after the brush has rotated from the raised state during the first imaging. After acquiring image data V2, the brush 44 returns to the standby position. The control device 100, for example, acquires the brightness of the edge L3 of the groove 49 of each abrasive material 46 from the image data V1 and V2, as explained in Figure 7, and determines whether or not the abrasive material 46 has detached and determines the wear state of the abrasive material 46. Then, it outputs an alarm according to the determination result.

[0068] Figures 15 and 17 show that droplets R3 of the moisturizing liquid R2 are removed from the sliding surface 48 or groove 49 when image data V1 and V2 are acquired. Even if droplets R3 remain on the sliding surface 48, the brush 44 is close to the window 52 at the imaging position, so as described above, the thickness of the liquid film formed by the moisturizing liquid R2 is relatively small. Therefore, this liquid film has little effect on the brightness of the sliding surface 48 and groove 49 in the image. Consequently, the condition of the brush 44 can be determined with high accuracy.

[0069] With the cleaning device 1 described above, the condition of the brush 44 can be determined from the image data V1 and V2 acquired by the camera 61 while the brush 44 is positioned at an imaging position partitioned within the processing space 30. Therefore, since it is not necessary for an operator to remove the brush 44 from the cleaning device 1 to check its condition, the effort required for such checks is reduced, and the decrease in the operational efficiency of the device is minimized, making it highly convenient.

[0070] Incidentally, the imaging position of the brush 44 (i.e., the brush 44 in the raised state) may be set to a position where the sliding surface 48 contacts the window 52, ​​as shown in Figure 18. Setting the imaging position in this way is preferable because it can more reliably suppress the influence of droplets R3 on the abrasive material 46 on the image brightness. Furthermore, when rotating the brush 44 to acquire image data V2 after acquiring image data V1, it is not necessary to lower the brush 44 from the imaging position as shown in Figure 16, but as previously mentioned, it is preferable to lower the brush 44 and rotate it in order to prevent damage to the window 52. Lowering the brush 44 is particularly preferable when the imaging position is such that the sliding surface 48 contacts the window 52, ​​as shown in Figure 18.

[0071] Alternatively, instead of lowering the brush 44, a lifting mechanism may be connected to the window frame 51, so that the brush 44 rotates to change direction when the window 52 is positioned higher than its position during imaging (i.e., the gap between the window 52 and the brush 44 is larger). Note that the angle at which the brush 44 rotates is not limited to 90° and may be changed as appropriate depending on the size of the inspection area L2 shown in Figure 6. The number of image data acquisitions may also be set as appropriate according to the angle at which the brush 44 rotates.

[0072] By the way, in the example configuration of the imaging mechanism 6 described in Figure 2, each component is provided so that the entire height of the illumination 62 and the entire height of the camera 61 fit within the height of the mirror 63. However, the arrangement of each component is not limited to this. As shown in Figure 19, the height of the imaging mechanism 6 can be kept down even if a portion of the height of the illumination 62 overlaps with the height of the mirror 63. Similarly, as shown in Figure 19, the height of the imaging mechanism 6 can be kept down even if a portion of the height of the camera 61 overlaps with the height of the mirror 63.

[0073] Incidentally, the height of the illumination 62 mentioned above specifically refers to the height of the light-emitting surface facing the imaging area 18 in the light-emitting device. For example, suppose the illumination 62 includes a light source such as a lamp and a housing that houses the light source, and only a portion of one side of this housing is configured as the aforementioned light-emitting surface made of glass or the like that can transmit light from the light source, while the other portion of that side is configured as a non-light-emitting surface made of metal or the like. If the height of the light-emitting surface does not overlap with the height of the mirror 63, but the height of the non-light-emitting surface overlaps with the height of the mirror 63, then the illumination 62 does not overlap with the height of the mirror 63. If the illumination 62 is positioned so that the height of the light-emitting surface overlaps with the height of the mirror 63, then the illumination 62 overlaps with the height of the mirror 63.

[0074] In the imaging mechanism 6 described in Figure 2, the positions of the camera 61 and the illumination 62 may be swapped, with the camera 61 positioned below the illumination 62. However, as the light from the illumination 62 reflected by the mirror 63 is directed downwards, it will pass through the field of view of the camera 61, which may make it difficult to obtain a clear image. Therefore, it is preferable to position the camera 61 above the illumination 62, as shown in Figure 2.

[0075] [Second Embodiment] The cleaning apparatus to which this technology is applied is not limited to an apparatus that cleans the back surface of a substrate with the sliding surface of the brush facing upward. That is, the cleaning apparatus may also be an apparatus that cleans the surface (top surface) of a substrate with the sliding surface facing downward, or an apparatus that cleans the top and bottom surfaces of a substrate with the sliding surfaces of two brushes facing upward and downward, respectively. Furthermore, the brush with the sliding surface facing downward can also be imaged by an imaging mechanism in the same way as the brush with the sliding surface facing upward, and the condition of the brush can be determined.

[0076] Figure 20 shows a longitudinal cross-sectional side view of the cleaning device 1A according to the second embodiment. In addition to the components described in the first embodiment, the cleaning device 1A includes a cleaning processing unit 4A. This cleaning processing unit 4A is configured such that the cleaning processing unit 4 is inverted vertically, and includes a brush 44A, a rotating mechanism 43A, and a moving mechanism 42A, which correspond to the brush 44, rotating mechanism 43, and moving mechanism 42, respectively. If the sliding surface of the abrasive material 46 provided on the brush 44A is 48A, then this sliding surface 48A faces downward, and the abrasive material 46 is provided on the base 45 of the brush 44A so that it is horizontal, just like the sliding surface 48. The abrasive material 46 of the brush 44A also has grooves 49, just like the abrasive material 46 of the brush 44. Because the abrasive material 46 is provided so that the sliding surface 48A faces downward, the grooves 49 are provided on the lower surface of the abrasive material 46. The moving mechanism 42A allows the brush 44A and the rotating mechanism 43A to move horizontally and vertically.

[0077] Furthermore, the cleaning device 1A is provided with a cleaning nozzle 37A and a moving mechanism 39A. The moving mechanism 39A allows the cleaning nozzle 37A to move horizontally between a position above the processing space 30, overlapping the processing space 30 in a top view, and outside the processing space 30. Cleaning liquid is supplied to the cleaning nozzle 37A from a cleaning liquid supply unit 38A, which is configured similarly to the cleaning liquid supply unit 38, and the cleaning liquid can be supplied from the cleaning nozzle 37A to a desired position on the surface of the wafer W. With the above configuration, the cleaning device 1A can perform cleaning on the back surface of the wafer W, as in the first embodiment, and can also perform cleaning on the surface of the wafer W by brushing with a brush 44A and supplying cleaning liquid from the cleaning nozzle 37A.

[0078] Alternatively, the cleaning processing unit 4, which includes the brush 44, may be omitted, and the apparatus may be configured so that only the surface of the wafer W is cleaned by the cleaning processing unit 4A. The brushing of the wafer W surface may be performed in the same way as the brushing of the back surface of the wafer W, or it may be performed differently. If the brushing is to be performed differently from that of the back surface, for example, the rotating brush 44A by the rotating mechanism 43 may be moved horizontally between the center and peripheral edges of the wafer W, which is rotated by the spin chuck 13.

[0079] Furthermore, the cleaning device 1A is equipped with an imaging mechanism 6A for imaging the underside of the brush 44A, and based on the image captured by this imaging mechanism 6A, the control device 100 makes a determination regarding the brush 44A in the same way as the determination regarding the brush 44. The configuration of the imaging mechanism 6A will be explained with reference to Figure 21, which is a longitudinal cross-sectional side view. The imaging mechanism 6A includes a camera 61A and an illumination 62A and is installed inside the box 71.

[0080] The box body 71 is provided, for example, embedded in the partition plate 10. A partition wall 74 is provided inside the box body 71, and the partition wall 74 divides the inside of the box body 71 into upper and lower sections, forming a lower region 72 and an upper region 73. The central part of this partition wall 74 is configured as a transparent window 52A, which transmits light in the same way as the window 52 in the first embodiment.

[0081] The upper part of the box 71 is open, and the moving mechanism 42A allows the brush 44A to be moved in and out of the upper region 73 through this opening. In this second embodiment, the imaging position of the brush 44A is above the window 52A within the upper region 73. Therefore, in this second embodiment, the imaging position of the brush 44A is in a region partitioned from the processing space 30 not only by the cup 31 but also by the box 71. Figure 20 shows the brush 44A at the imaging position, and for example, at this imaging position, the sliding surface 48A is slightly away from the window 52A.

[0082] An imaging mechanism 6A, namely a camera 61A and illumination 62A, is provided in the lower region 72. With the brush 44A positioned at the imaging location, the lower surface of the brush 44A, including the sliding surface 48A and groove 49, is illuminated by light from the illumination 62A supplied through the window 52A. In this illuminated state, the lower surface of the brush 44A is imaged by the camera 61A through the window 52A. Therefore, in this second embodiment, the imaging mechanism 6A images the brush 44A located on the upper side (other side) of the window 52A from the lower side (one side) of the window 52A. Based on the acquired image, the control device 100 makes various judgments regarding the brush 44A, similar to the brush 44, and outputs an alarm if necessary based on the judgment.

[0083] Furthermore, the configuration of the illumination 62A, which will be described in detail later, prevents the brightness of the sliding surface 48A and groove 49 in the image from becoming excessive, and the lower surface of the brush 44A is illuminated with high uniformity in the circumferential direction of the brush 44. Therefore, in making a determination regarding the brush 44A, unlike in the first embodiment, in this second embodiment, multiple images are not taken by changing the orientation of the brush 44A, and the state of each sliding surface 48A is determined from a single image data.

[0084] Let's explain the arrangement of camera 61A and illumination 62A in more detail. For this explanation, please also refer to Figure 22, which is a plan view of illumination 62A. Camera 61A is positioned on the bottom of the box 71, with its field of view directed upwards. More specifically, the optical axis of the lens on camera 61A is directed vertically upwards.

[0085] The illumination 62A is positioned in an annular shape when viewed from above, opposite the sliding surface 48A of the brush 44A located at the imaging position. In other words, light is emitted in an annular shape from the illumination 62A toward the sliding surface 48A. When viewed from the side, the direction of this light emission is oblique; that is, it is inclined with respect to the vertical and horizontal directions.

[0086] In Figures 21 and 22, the illumination center line L4 is shown as a dashed line, connecting the points with the greatest light intensity at each point along the optical path for the light emitted from illumination 62A. Therefore, this illumination center line L4 corresponds to the optical axis L1 of illumination 62 shown in Figure 4. In this example, illumination 62A is annular, and light is emitted from all sides of it. Therefore, in a top view, the illumination center line L4 is annular, but in Figure 22, it is shown as multiple dashed arrows by thinning out the lines. It can also be said that these dashed arrows are optical axes, and the illumination center line L4 is formed when the optical axes are aligned in the circumferential direction of illumination 62.

[0087] As shown in Figure 21, the irradiation center line L4 is inclined at an acute angle with respect to the sliding surface 48A of the imaging position and intersects at a position below the sliding surface 48A of the imaging position (i.e., at a position away from the brush 44A). Setting the intersection position of the irradiation center line L4, which corresponds to the optical axis, away from the brush 44A in this way is preferable because it can suppress excessive brightness of the sliding surface 48A and groove 49 in the image, thereby improving the accuracy of the determination regarding the brush 44A.

[0088] Furthermore, the direction toward the irradiation center line L4 is tilted in a side view with respect to direction A2 (see Figure 21), which is perpendicular to the sliding surface 48A. That is, the direction toward the irradiation center line L4 is different from the direction toward the depth of the groove 49. Therefore, this second embodiment is also preferable because, as with the first embodiment, it is easy to distinguish between the sliding surface 48 and the groove 49 in the image, thus improving the accuracy of the determination regarding the brush 44A. Note that direction A2 is also the vertical direction.

[0089] The cleaning device 1A of the second embodiment described above also provides the same effects as the cleaning device 1. Although the illumination 62A of the second embodiment is shown as a continuous annular shape, it may also be a discontinuous annular shape. Therefore, multiple illuminations 62A may be arranged along the circumference of the brush 44A in a top view, with each illumination 62A irradiating light toward the brush 44A. In the first embodiment, instead of the imaging mechanism 6, a mechanism in which the imaging mechanism 6A is inverted may be provided to image the upper surface of the brush 44 and make a determination regarding the brush 44.

[0090] [Third Embodiment] The cleaning device 1B according to the third embodiment has a configuration that is generally the same as the cleaning device 1 of the first embodiment, and the differences from the cleaning device 1 will be explained below. The cleaning device 1B is not provided with a mirror 63, and the camera 61 images the brush 44B provided in the cleaning device 1B and located at the imaging position from above. Figures 23 and 24 are a side view and a top view, respectively, of the brush 44B provided in the cleaning device 1B, showing the state in which the brush 44B is located at the imaging position.

[0091] Brush 44B has the same configuration as brush 44, except that a cleaning member 81 is provided on the base 45, and the imaging position of brush 44B is the same as the imaging position described in the first embodiment. Brush 44B brushes the back surface of the wafer W using a cleaning member 81 and an abrasive material 46 made of different materials. Therefore, the cleaning member 81 also slides relative to the bottom surface of the wafer W, similar to the abrasive material 46. The cleaning member 81 is, for example, an elastic material, and more specifically, it may be made of a sponge or the like. As mentioned above, the multiple abrasive materials 46 provided on brush 44B can be viewed together as an annular member, and this annular member formed by the multiple abrasive materials 46 is shown as 46A in Figures 23 and 24. The cleaning member 81 is provided on the base 45 of brush 44B surrounded by this annular member 46A, and is formed in an annular shape that is concentric with the annular member 46A in a plan view. Therefore, the cleaning member 81 is formed along the rotational direction of the brush 44B.

[0092] The arrangement of camera 61 and illumination 62 will now be described. Camera 61 and illumination 62 are positioned above window 52 via support members (not shown). More specifically, in this example, camera 61 is positioned such that the optical axis (not shown) of its lens is tilted with respect to the vertical. In other words, camera 61 is positioned to image the upper surface of brush 44B from an oblique angle above. The dotted line in Figure 23 represents the boundary between the imaging range and the area outside the imaging range of camera 61, and the entire upper surface of brush 44B is within the imaging range of camera 61. In this third embodiment, unlike the first embodiment, multiple image acquisitions are not performed by changing the orientation of brush 44B, and the wear of the abrasive material 46 is determined from images acquired without changing the orientation of brush 44.

[0093] To elaborate on the arrangement of the illumination 62, the optical axis L1 of the light emitted by the illumination 62 is directed diagonally downward in a side view, as shown in Figure 23. As shown in Figure 24, this optical axis L1 is formed in a position that does not overlap with the brush 44 in a plan view. This is because if the optical axis L1 is too close to the brush 44B, in the region of the brush 44B relatively close to the optical axis L1, it may become difficult to form contrast, i.e., a difference in brightness, between the grooves 49 of the abrasive material 64 and the sliding surface 48 adjacent to the grooves 49 in the image, making it difficult to detect the grooves 49. Furthermore, the optical axis L1 does not pass through the window 52. This prevents the relatively strong light forming the optical axis L1 from illuminating a component placed near the imaging area of ​​the brush 44B, and the resulting reflected light from illuminating the upper surface of the brush 44B. By suppressing the illumination of the upper surface of the brush 44B with this reflected light, the difficulty in forming contrast between the grooves 49 and the sliding surface 48 is suppressed.

[0094] In Figure 24, when imaging the brush 44B, the extension direction of the groove 49 located closest to the illumination 62 in a plan view (more specifically, the extension direction of the side surface forming the groove 49) is shown as L5. It is preferable that this extension direction L5 is not parallel to the direction of the optical axis L1, as shown in the figure. The groove 49 closest to the illumination 62 is easily illuminated by strong light from the illumination 62, making it difficult to achieve a sufficient contrast between the sliding surface 48 and the groove 49. Furthermore, around the optical axis L1, relatively high-intensity light is illuminated in the direction along the optical axis L1, so if the extension direction L5 is parallel to the optical axis L1, the amount of light incident on the groove 49 is large, making it difficult to form a brightness difference between the sliding surface 48 and the side surface of the groove 49. In other words, the above contrast is difficult to form. Therefore, in this example, by ensuring that the optical axis L1 and the extension direction L5 of the groove 49 are not parallel during imaging, the amount of light incident on the groove 49 is limited, thereby increasing the contrast.

[0095] The process for determining the wear state of the abrasive material 46 on the brush 44B in this cleaning device 1B is as follows: The brush 44B is stationary at the imaging position, and imaging is performed by the camera 61 while light is irradiated from the illumination 62. Due to the arrangement of the camera 61 described above, the acquired image of the brush 44B is generally tilted, as shown in Figure 3. The control device 100 corrects the acquired image to convert it into an image of the brush 44B in a plan view. In other words, it corrects the image so that it becomes an image of the brush 44B as shown in Figure 23. More specifically, this correction is performed so that each of the multiple abrasive materials 46 is approximately the same size, so that the position of the groove 49 and the wear state can be determined similarly for each of the multiple abrasive materials 46 based on the brightness described in the first embodiment. Furthermore, if, in the corrected image, sufficient contrast is not formed between the grooves 49 in the abrasive material 46 and the sliding surface 48, making it impossible to identify the location of some of the grooves 49, then, for example, the wear condition of the abrasive material 46 with those grooves 49 formed may not be determined, and only the wear condition of the abrasive material 46 with the other grooves 49 formed may be determined.

[0096] After determining the wear state of the abrasive material 46 as described above, the control device 100, which is a determination unit that performs various determinations, determines, for example, whether or not it was possible to identify all the grooves 49 of the abrasive material 46 on the brush 44. If it is determined that the grooves 49 have been identified for all the abrasive material 46, the control device 100 determines that the brightness of the entire annular member 46A formed by the abrasive material 46 in the acquired image (an image corrected to be a plan view as described above) is appropriate. Furthermore, it determines that the brightness of each part of the cleaning member 81, which is positioned slightly away from the optical axis L1 relative to the annular member 46A, is also appropriate, and that it is possible to determine whether or not there is an abnormality in the cleaning member 81 from the image, and therefore determines whether or not there is an abnormality in the cleaning member 81.

[0097] Specifically, to determine if there is an abnormality in the cleaning member 81, the control device 100 detects the deformation, damage, or soiling of the cleaning member 81 from the corrected image described above according to a predetermined algorithm, and outputs an alarm according to the detection result. If it is determined that the position of some or all of the grooves 49 could not be identified, the control device 100 will consider that at least a part of the cleaning member 81 could not be properly imaged, and will not perform the above-described determination of abnormality in the cleaning member 81.

[0098] Therefore, in this cleaning device 1B, the appropriateness of the imaging state of the abrasive material 46, which is arranged at different positions forming the annular member 46A, is determined from the image. If it is determined to be appropriate, the state of the cleaning member 81 provided along the annular member 46A in the region surrounded by the annular member 46A is determined from the same image. In other words, the state of the cleaning member 81 is determined according to the state of multiple positions on the annular member 46A. Thus, in this cleaning device 1B, the effort required for image acquisition is reduced, while the presence or absence of abnormalities in the cleaning member 81 can be determined with high accuracy.

[0099] In the example of camera 61 arrangement described in Figures 23 and 24, the camera 61 images the top surface of the brush 44B from an oblique angle, thereby suppressing the large vertical distance of the camera 61 relative to the brush 44B and thus reducing the height of the cleaning device 1B. However, the camera 61 is not limited to this arrangement. For example, the camera 61 may be positioned directly above the window 52 (i.e., directly above the brush 44B) such that the optical axis of the camera 61's lens is directed vertically downward to image the brush 44B. Incidentally, the image correction after imaging described above is not required. In particular, when the brush 44B is imaged from directly above in this way, each abrasive material 46 can be imaged with a highly uniform size, so such correction may not be necessary. In addition to converting from an oblique view to a plan view, image correction may also be performed to remove distortion in the image relative to the real image of the brush 44B.

[0100] Incidentally, the camera 61 may also detect abnormalities other than wear of the abrasive material 46 from the image acquired to determine wear of the abrasive material 46, and an alarm may be output when such abnormalities are detected. Examples of abnormalities other than wear include chipping of the brush 44B of the abrasive material 46 in the direction of rotation, cracking of the sliding surface 48, and detachment from the base 45.

[0101] Regarding the detection of chipping of the abrasive material 46 in the rotational direction, the control device 100 may, for example, detect the width of the gap 47 between the abrasive material 46 in the image, compare the detected value with a reference value, and if the detected value is larger than the reference value, it may be detected as an abnormality in chipping of the abrasive material 46. Regarding the detection of cracks in the sliding surface 48, for example, the control device 100 may determine whether or not there is a region on the sliding surface 48 where the brightness is lower than a predetermined value, which is considered a region where cracks have occurred.

[0102] Furthermore, to detect the detachment of the abrasive material 46 from the base 45, the control device 100 stores in memory an image (referred to as the old image) acquired by the camera 61 to determine wear of the abrasive material 46. The control device 100 then compares the old image with an image (referred to as the new image) acquired by the camera 61 to determine wear of the abrasive material 46. If the abrasive material 46 has detached, the area with relatively low brightness between the abrasive material 46 (gap 47) will be longer in the new image compared to the old image. Therefore, for example, the control device 100 can compare the length of this area with a pre-prepared reference value, and if it is longer than the reference value, it can determine that detachment has occurred.

[0103] Furthermore, in each embodiment, the substrate to be processed is not limited to a wafer, but may also be, for example, a substrate for manufacturing exposure masks or a substrate for manufacturing flat panel displays. The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The above embodiments may be omitted, replaced, modified and combined in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0104] W wafer 1. 1A Washing device 18 Imaging area 30 Processing space 31 cups 48, 48A sliding surface 52, 72A windows 44, 44A brush 6, 6A Imaging mechanism 61, 61A Camera

Claims

1. A processing space forming unit that forms a processing space for cleaning the substrate, To clean the substrate in the processing space, a brush is provided which has a sliding surface that slides relative to the substrate, An imaging mechanism comprising a camera provided in a region separated from the processing space on one side of a transparent window, and which images the sliding surface of the brush located on the other side of the window through the window, A cleaning device equipped with the following features.

2. The cleaning apparatus according to claim 1, wherein imaging of the sliding surface of the brush is performed with respect to the brush located laterally away from the processing space.

3. The imaging mechanism includes a mirror that reflects the image of the sliding surface toward the camera, The cleaning apparatus according to claim 1 or 2, wherein, in a top view, the position of the processing space relative to the mirror is on the opposite side from the side that reflects the image of the sliding surface.

4. The imaging mechanism is equipped with lighting to illuminate the brush when the camera takes an image. The cleaning apparatus according to claim 1 or 2, wherein the light from the illumination is irradiated in a direction inclined with respect to the direction perpendicular to the sliding surface.

5. The sliding surface slides relative to the back surface of the substrate, The imaging mechanism includes a mirror that reflects the image of the sliding surface toward the camera, The cleaning apparatus according to claim 4, wherein the camera, the mirror, and the lighting are located above the processing space.

6. Unlike the height of the camera and the height of the lighting, The cleaning apparatus according to claim 5, wherein the height of the lighting overlaps with at least a portion of the height at which the mirror is provided.

7. The cleaning apparatus according to claim 5, wherein the mirror is provided such that the path of light reflected by the mirror, along an optical axis that continuously connects the centers of the light emitted from the illumination, is away from the sliding surface at the position where imaging is performed by the camera.

8. The aforementioned lighting is provided in an annular shape at a position opposite the brush, The cleaning apparatus according to claim 1 or 2, wherein the path of the optical axis connecting the centers of the light emitted from the illumination intersects at a position spaced apart from the brush.

9. The cleaning apparatus according to claim 1 or 2, wherein imaging by the camera is performed when the brush is in an elevated state, closer to the window than the standby position in which the brush is waiting.

10. The cleaning apparatus according to claim 9, wherein the raised state is a state in which the sliding surface is in contact with the window.

11. The cleaning apparatus according to claim 9, wherein imaging by the camera is performed in the state after the brush has been rotated from the raised state.

12. The brush has a plurality of protrusions that form the sliding surface and are arranged laterally, The cleaning apparatus according to claim 1 or 2, further comprising a determination unit that acquires brightness corresponding to each of the plurality of protrusions and determines the wear state of the brush from the brightness obtained by excluding brightness corresponding to a preset abnormal condition from the acquired brightness.

13. The imaging mechanism is equipped with lighting to illuminate the brush when the camera takes an image. The cleaning apparatus according to claim 1 or 2, wherein the optical axis formed by the illumination does not overlap with the brush in a plan view.

14. The brush is provided with a plurality of grooves that divide the sliding surface. A determination unit is provided that determines the state of the brush based on the brightness of each groove in the image acquired by the camera. The cleaning device according to claim 13, wherein, during the imaging, the extension direction of the groove at the position closest to the illumination in a plan view among the plurality of grooves is not parallel to the direction of the optical axis.

15. The brush is provided with an annular member having the sliding surface, A cleaning member that slides relative to the substrate is provided in the region of the brush surrounded by the annular member. The cleaning apparatus according to claim 1 or 2, further comprising a determination unit that determines the state of the cleaning member from the image according to the imaging state of multiple positions of the annular member in the image acquired by the camera.

16. A processing space forming unit that forms a processing space for cleaning the substrate, A method for operating a cleaning apparatus comprising a brush having a sliding surface that slides relative to the substrate for cleaning the substrate in the processing space, A method for operating a cleaning apparatus, which includes an imaging step of imaging the sliding surface of the brush with a camera provided in an imaging mechanism located on one side of a transparent window and in a region partitioned from the processing space, and located on the other side of the window via the window.

17. A method for operating a cleaning apparatus according to claim 16, further comprising the step of illuminating the brush by irradiating it with light from the lighting provided by the imaging mechanism in a direction inclined with respect to the direction perpendicular to the sliding surface when imaging is performed by the camera.

18. The method for operating the cleaning apparatus according to claim 16 or 17, wherein the imaging step is performed in an elevated state in which the brush is closer to the window than the waiting position in which the brush is waiting.

19. A method for operating a cleaning apparatus according to claim 18, further comprising the step of taking an image with the camera after rotating the brush from the raised state.

20. A computer program used in a cleaning device, The computer program is a program in which a group of steps is arranged to execute the method of operating the cleaning apparatus described in claim 16.

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