Cleaning device and cleaning method

Abstract

To reliably clean wafers by suppressing adhesion of particles to a cleaning brush.SOLUTION: A cleaning method implemented in a cleaning device includes a holding portion 3, a wafer cleaning unit 1 having a cleaning brush 2, a brush cleaning unit 20 having a cleaning plate 21 that contacts the cleaning brush 2 to clean the cleaning brush 2, a moving unit 30 that moves the cleaning brush 2 and the cleaning plate 21 relatively in directions of approaching and separating them, and a controller 40, and after cleaning the surface of a wafer W with the cleaning brush, the controller controls the moving unit to bring the cleaning brush and the cleaning plate 21 closer together from a contact state to deform the cleaning brush 2, and then separates the cleaning brush 2 and the cleaning plate 21, performing a deformation operation at least once to restore the cleaning brush 2 to its pre-deformation state.SELECTED DRAWING: Figure 8C

Description

[Technical Field]

[0001] The present invention relates to a cleaning apparatus including a wafer cleaning unit for cleaning wafers and a brush cleaning unit for cleaning cleaning brushes, and a cleaning method carried out using the cleaning apparatus. [Background technology]

[0002] In semiconductor manufacturing processes, for example, a cleaning process is carried out by various cleaning devices to remove grinding debris (hereinafter referred to as "particles") adhering to the surface of a wafer after grinding and polishing the wafer, and to clean the surface of the wafer. Known cleaning devices include a holder that holds the wafer and rotates it in the circumferential direction, and a cleaning brush that rotates and oscillates in the radial direction of the wafer while contacting the surface of the wafer held and rotated by the holder (see, for example, Patent Document 1).

[0003] In the above-mentioned cleaning device, a cleaning brush that rotates and oscillates in the radial direction of the wafer is brought into contact with the surface of the rotating wafer while supplying cleaning liquid, so that the entire surface of the wafer is cleaned by the cleaning brush and particles adhering to the surface of the wafer are removed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-017454 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is a problem in that particles removed from the surface of the wafer by cleaning may adhere to the cleaning brush itself, which may result in insufficient cleaning of the next wafer to be cleaned.

[0006] The present invention has been made in view of the above problems, and its object is to provide a cleaning apparatus and a cleaning method that can suppress adhesion of particles to a cleaning brush and reliably clean wafers. [Means for solving the problem]

[0007] The first invention for achieving the above-mentioned object is a cleaning device comprising: a holding section for holding a wafer; a cleaning brush that contacts the wafer held by the holding section to clean the wafer; a wafer cleaning unit having a cleaning liquid supply means that supplies cleaning liquid toward the wafer; a brush cleaning unit having a cleaning plate that contacts the cleaning brush to clean the cleaning brush; and a moving unit that moves the cleaning brush and the cleaning plate relatively in directions toward and away from each other, and is characterized by having a controller that controls the moving unit to perform at least one deformation operation to bring the cleaning brush and the cleaning plate closer together from a contact state to deform the cleaning brush, and then separate the cleaning brush and the cleaning plate to restore the cleaning brush to its pre-deformation state.

[0008] The second invention is a cleaning method carried out in the cleaning apparatus according to the first invention, characterized in that after the surface of the wafer is cleaned with the cleaning brush, the controller controls the moving unit to bring the cleaning brush and the cleaning plate closer together from a contact state to deform the cleaning brush, and then separates the cleaning brush and the cleaning plate, performing a deformation operation at least once to restore the cleaning brush to its pre-deformation state. [Effects of the Invention]

[0009] According to the cleaning method of the present invention implemented in the cleaning apparatus of the present invention, the cleaning liquid supply means supplies cleaning liquid to the wafer while the surface of the wafer is cleaned with the cleaning brush, and then the controller controls the moving unit to perform at least one deformation operation of the cleaning brush, i.e., deforming the cleaning brush by bringing the cleaning brush and the cleaning plate closer together from a contact state, and then separating the cleaning brush and the cleaning plate to restore the cleaning brush to its pre-deformation state. Therefore, the cleaning liquid absorbed by the cleaning brush during wafer cleaning is effectively discharged from the cleaning brush together with particles by the pumping action of the deformation operation of the cleaning brush. This eliminates the problem of particles removed from the wafer surface during cleaning adhering to the cleaning brush itself, and allows the cleaning brush to be used to clean the next wafer effectively. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view showing a configuration of a main part of a brush cleaning unit of a cleaning device according to the present invention. [Figure 2] 1 is a partial vertical cross-sectional view of a main part (moving unit part) of a brush cleaning unit of a cleaning device according to the present invention. [Figure 3] 1(a) to 1(d) are perspective views showing various forms of cleaning brushes of a cleaning device according to the present invention. [Figure 4] 1 is a partial vertical cross-sectional view of a main part of a cleaning device according to the present invention. [Figure 5] 1 is a flowchart showing the procedure of a cleaning method according to the present invention. [Figure 6] 1 is a partial vertical cross-sectional view showing a state in which a wafer is being cleaned by a wafer cleaning unit of a cleaning apparatus according to the present invention; [Figure 7] 1 is a partial plan view showing a state in which a wafer is being cleaned by a wafer cleaning unit of a cleaning apparatus according to the present invention; [Figure 8A] 4 is a partial vertical cross-sectional view showing the deformation operation of the cleaning brush (approaching operation of the cleaning brush) in the cleaning method according to the present invention. FIG. [Figure 8B]4 is a partial vertical cross-sectional view showing the deformation operation of the cleaning brush (contact operation of the cleaning brush) in the cleaning method according to the present invention. FIG. [Figure 8C] 4 is a partial vertical cross-sectional view showing the deformation operation of the cleaning brush (the pressing operation of the cleaning brush) in the cleaning method according to the present invention. FIG. [Figure 8D] 4 is a partial vertical cross-sectional view showing the deformation operation of the cleaning brush (restoration operation of the cleaning brush) in the cleaning method according to the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0012] First, the configuration of the cleaning device according to the present invention will be described below with reference to FIGS.

[0013] [Cleaning equipment configuration] The cleaning apparatus according to the present invention comprises, as its main components, a wafer cleaning unit 1 shown in Fig. 1, a brush cleaning unit 20 shown in Fig. 4, a moving unit 30 (see Fig. 2) that moves the cleaning brush 2 of the wafer cleaning unit 1 up and down in a direction toward and away from the cleaning plate 21 of the brush cleaning unit 20, and a controller 40 (see Fig. 2) that controls the moving unit 30. Below, the configurations of the wafer cleaning unit 1, the brush cleaning unit 20, the moving unit 30, and the controller 40, which are the main components of the cleaning apparatus according to the present invention, will be described.

[0014] (Wafer cleaning unit) 1, the wafer cleaning unit 1 is a unit that cleans the top and bottom surfaces of a thin, disk-shaped wafer W, and is equipped with a holder 3 that holds the wafer W and rotates it in a circumferential direction, and a pair of upper and lower cleaning brushes 2 that rotate and oscillate in a radial direction of the wafer W while contacting the surfaces (top and bottom surfaces) of the wafer W held and rotated by the holder 3. Here, the wafer W is made of, for example, a single-crystal silicon base material, and both sides of the wafer W have been ground in a preceding grinding process.

[0015] 1, the holding section 3 is composed of a first holding unit 3A and two second holding units 3B, and the first holding unit 3A houses two electric motors (not shown) that serve as rotational drive sources in a horizontally arranged arm-shaped case 4. Each electric motor extends vertically upward from an output shaft (motor shaft) 5, and a holding roller 6 is attached to the upper end of the output shaft (motor shaft) 5 that protrudes vertically upward from the upper surface of the case 4. Each holding roller 6 has a large diameter portion 6a and a small diameter portion 6b, and the outer circumferential surface of the small diameter portion 6b is tapered, decreasing in diameter as it goes downward.

[0016] Each of the two second holding units 3B houses an electric motor (not shown) serving as a rotational drive source in a vertically disposed cylindrical holder 7. An output shaft (motor shaft) 8 extends vertically upward from each electric motor, and has an upper end protruding vertically upward from the upper surface of the holder 7. Each holding roller 9 is attached to the upper end of the output shaft (motor shaft) 8. Each holding roller 9 has a large diameter portion 9a and a small diameter portion 9b, and the outer circumferential surface of the small diameter portion 9b is tapered downward (see FIG. 6).

[0017] The first holding unit 3A and the second holding unit 3B configured as described above are supported so as to be relatively movable in the horizontal direction. When cleaning a wafer W, the outer periphery of the wafer W is held by a total of four holding rollers 6, 9 provided on the first holding unit 3A and the second holding unit 3B. The first holding unit 3A and the second holding unit 3B are biased toward each other by a biasing means (not shown), such as a spring, so that the holding rollers 6, 9 provided thereon sandwich the outer periphery of the wafer W. The outer periphery of the wafer W is sandwiched between the boundaries of the small diameter portions 6b, 9b and the large diameter portions 6a, 9a of the four holding rollers 6, 9, and held horizontally (see FIG. 6 ). In this embodiment, the outer periphery of the wafer W is sandwiched by four holding rollers 6, 9. However, the number of holding rollers 6, 9 is not limited to four and may be any number as long as it is plural.

[0018] The pair of upper and lower cleaning brushes 2 are supported rotatably and vertically movable at the tip of a pair of horizontally rotatable arm-shaped cases 10. As shown in Fig. 2, each of the upper and lower cases 10 houses a moving unit 30 that moves the cleaning brushes 2 toward and away from each other, and the configuration of these moving units 30 will be described later.

[0019] In the wafer cleaning unit 1, cleaning nozzles 11 constituting part of a cleaning liquid supply means for spraying cleaning liquid toward the upper and lower surfaces of the wafer W when cleaning the upper and lower surfaces of the wafer W with a pair of upper and lower cleaning brushes 2 are arranged obliquely above and below the wafer W, and each cleaning nozzle 11 is connected to a cleaning liquid supply source (not shown). Note that pure water is preferably used as the cleaning liquid.

[0020] Here, each cleaning brush 2 is a highly porous, sponge-like, disk-shaped member made of polyvinyl alcohol (PVA) or the like, and shapes such as those shown in Figures 3(a) to 3(d) can be used. Specifically, the cleaning brush 2A shown in Figure 3(a) is annularly shaped with a circular hole 2a formed in the center, while the cleaning brush 2B shown in Figure 3(b) has multiple grooves 2b formed radially in the annular portion of the outer periphery of the cleaning brush 2A shown in Figure 3(a). The cleaning brush 2C shown in Figure 3(c) has multiple radial grooves 2c formed in a circular contact area that contacts the surface of the wafer W, and the cleaning brush 2D shown in Figure 3(d) has multiple lattice-like grooves 2d formed in a circular contact area that contacts the surface of the wafer W.

[0021] (Brush cleaning unit) The brush cleaning unit 20 is a unit that cleans each cleaning brush 2 used to clean the wafer W. As shown in Fig. 4, rectangular glass cleaning plates 21, each having a surface area larger than that of the cleaning brush 2, are attached to the top and bottom surfaces of the tip of an arm 22 that can rotate in a horizontal plane around a vertical axis (not shown). The surface of each glass cleaning plate 21 (the surface that comes into contact with the cleaning brush 2 to clean it) is a smooth plane, but it may also have an uneven surface. Furthermore, each cleaning plate 21 may be made of a material other than glass, and may have any shape other than a rectangle. .

[0022] An ultrasonic oscillator 23 that generates ultrasonic vibrations is attached to the tip of the arm 22, and a power source 24 that applies a voltage to drive the ultrasonic oscillator 23 is electrically connected to the ultrasonic oscillator 23. Here, a piezoelectric element such as a piezo element is used for the ultrasonic oscillator 23.

[0023] The brush cleaning unit 20 is provided with cleaning water supply means 25 for supplying cleaning water to each cleaning brush 2, and alkaline solution supply means 26 for supplying alkaline solution to each cleaning brush 2. In this embodiment, pure water is used as the cleaning water, and an aqueous ammonia (NH3) solution is used as the alkaline solution.

[0024] Here, cleaning water supply means 25 includes supply channel 22a formed horizontally inside arm 22, supply channel 22b extending vertically from the end of supply channel 22a, supply grooves 22c formed on the upper and lower surfaces of arm 22 to which each cleaning plate 21 is attached, and a plurality of supply holes 21a formed vertically in each cleaning plate 21, with supply channel 22b connected to each of the upper and lower supply grooves 22c, and each supply groove 22c connected to the plurality of supply holes 21a formed in each cleaning plate 21. In cleaning water supply means 25, supply channel 22a formed inside arm 22 is connected to cleaning water supply source 28 via piping 27a, and piping 27a is provided with on-off valve V1. Note that on-off valve V1 is electrically connected to controller 40, and its opening and closing operation is controlled by controller 40.

[0025] Similarly to the cleaning water supply means 25, the alkaline solution supply means 26 also includes a supply channel 22d formed horizontally inside the arm 22 and a supply channel 22e extending vertically from the end of the supply channel 22d, with the supply channel 22e being connected to supply grooves 22c formed on the upper and lower surfaces of the arm 22. In the alkaline solution supply means 26, the supply channel 22d formed inside the arm 22 is connected to an alkaline solution supply source 29 via a pipe 27b, and an on-off valve V2 is provided on the pipe 27b. The on-off valve V2 is electrically connected to the controller 40, and its opening and closing operation is controlled by the controller 40.

[0026] In the brush cleaning unit 20 configured as described above, when cleaning the upper and lower cleaning brushes 2 used to clean the wafer W, the upper and lower cleaning brushes 2 pivot so as to sandwich from above and below the upper and lower cleaning plates 21 fixed to the upper and lower ends of the arm 22, as shown in Fig. 4. Note that the arm 22 may be configured to pivot horizontally by a drive source (not shown) so that the upper and lower cleaning plates 21 are positioned between the upper and lower cleaning brushes 2 that are spaced apart from each other; cleaning of the cleaning brushes 2 by this brush cleaning unit 20 will be described later.

[0027] (Mobile unit) The moving unit 30 is a unit that moves the pair of upper and lower cleaning brushes 2 up and down relatively in directions in which they approach and move away from each other, and is provided at the tip of each of the upper and lower cases 10, as shown in Fig. 2. Each moving unit 30 is composed of an electric motor 31 as a drive source, a ball spline 32 that converts the rotation of each electric motor 31 into up and down movement of each cleaning brush 2, and the like.

[0028] In each moving unit 30, each electric motor 31 is fixed to a cylindrical housing 35 with a bottom supported at the tip of each case 10, and a cylindrical holder 33 with a bottom is attached to the tip of an output shaft (motor shaft) 31a extending vertically from each electric motor 31. A cylindrical spline nut 32a is fitted inside each holder 33, and each holder 33 and each spline nut 32a are rotatably supported on the housing 35 by a pair of ball bearings 34.

[0029] A cylindrical guide member 12 is attached vertically to the underside of the tip of each case 10, and an end of a disk-shaped mount 36 that moves up and down while being guided by the guide member 12 is fitted and held inside each guide member 12. An end of a spline shaft 32b extending vertically from the center of each mount 36 is threadedly engaged with each spline nut 32a, and each spline shaft 32b and each spline nut 32a constitutes each ball spline 32. Each ball spline 32 transmits the rotation of the output shaft (motor shaft) 31a of each electric motor 31 to each cleaning brush 2 and converts the rotation of the output shaft (motor shaft) 31a of each electric motor 31 into up and down movement of each cleaning brush 2.

[0030] A disk-shaped cleaning brush 2 is attached to the end face of each mount 36, and each cleaning brush 2 and each mount 36 are constantly biased in a direction away from each other by a spring 37 compressed between the spline nut 32a on the outer periphery of the spline shaft 32b and the mount 36.

[0031] Therefore, when each electric motor 31 is started and each output shaft (motor shaft) 31a is rotated forward or backward, the holder 33 and spline nut 32a attached to the end of each output shaft 31a rotate forward or backward together with the output shaft 31a, and each spline shaft 32b threaded onto each spline nut 32a moves up and down together with each mount 36 and each cleaning brush 2.

[0032] Each electric motor 31 is fitted with an encoder 38 that detects the rotation speed and rotation direction of the electric motor 31, and each encoder 38 and each electric motor 31 are electrically connected to a controller 40. Therefore, when a detection signal from each encoder 38 is sent to the controller 40, the controller 40 controls the drive of each electric motor 31 based on the received detection signal.

[0033] (controller) The controller 40 includes a CPU (Central Processing Unit) that performs arithmetic processing according to a control program, and storage units such as a ROM (Read Only Memory) and a RAM (Random Access Memory). In particular, in this embodiment, the controller 40 controls each moving unit 30 to bring each cleaning brush 2 and each cleaning plate 21 closer to each other from a state in which they are in contact with each other, thereby elastically deforming each cleaning brush 2, and then separates each cleaning brush 2 from each cleaning plate 21, thereby restoring each cleaning brush 2 to its pre-deformation state by its own elastic restoring force, at least once. This will be described in detail later.

[0034] [Function of the cleaning device] Next, the operation of the cleaning apparatus configured as described above, specifically, the method for cleaning the wafer W by the wafer cleaning unit 1 and the method for cleaning the cleaning brush 2 by the brush cleaning unit 20 will be described below based on Figures 6 to 8 and the flowchart shown in Figure 5.

[0035] (Wafer cleaning method) First, before starting the cleaning operation, the number of times M the wafer W is cleaned before the cleaning brush 2 is cleaned is set, and the number of times m the cleaning brush 2 counted for each cleaning of the wafer W is set to 0 (m=0). Also, the number of times N the deformation operation described below is performed when the cleaning brush 2 is cleaned is set, and the number of times n the deformation operation is counted for each deformation operation is set to 0 (n=0) (step S1 in FIG. 5). In this embodiment, the number of times M the wafer W is cleaned before the deformation operation of the cleaning brush 2 is performed is set to 1 (i.e., the deformation operation of the cleaning brush 2 is performed every time the wafer W is cleaned), and the number of times N the deformation operation is set to 10 (N=10). In other words, the deformation operation of the cleaning brush 2 is performed 10 times each time cleaning of the wafer W is completed.

[0036] Incidentally, the number of times M the wafers W are cleaned before the deforming operation of the cleaning brush 2 is performed and the number of times N the cleaning brush 2 deforms can be set to any value. For example, M may be set to 5 or 10 (the cleaning brush 2 deforms every time cleaning of 5 or 10 wafers W is completed), or M may be set to (the number of wafers W stored in the cassette). Furthermore, the number N of times the cleaning brush 2 deforms can be set to any value, not limited to 10 times.

[0037] Next, cleaning of the wafer W by the wafer cleaning unit 1 is performed as shown in Figures 6 and 7 (step S2 in Figure 5). That is, as shown in Figures 1, 6, and 7, the first holding unit 3A and the second holding unit 3B are moved horizontally in a direction toward each other, and the outer peripheral edge of the wafer W is clamped by a total of four holding rollers 6, 9 provided in these first holding unit 3A and second holding unit 3B to hold the wafer W horizontally. Then, from this state, an electric motor (not shown) is started to rotate the holding rollers 6, 9 in the direction of the arrows in Figure 7. Then, the wafer W held horizontally by the four holding rollers 6, 9 rotates at a predetermined speed in the direction of the arrows in Figure 7.

[0038] As described above, when the wafer W is rotating at a predetermined speed, when the electric motors 31 of the upper and lower moving units 30 shown in Figure 2 are started, the output shafts 31a of the electric motors 31 rotate, and the rotation of each output shaft 31a is transmitted to each mount 36 via the spline nuts 32a and spline shafts 32b that constitute the ball spline 32. As a result, each mount 36 and each cleaning brush 2 attached thereto are rotated at a predetermined speed in the direction of the arrow in Figure 7 (the same as the rotation direction of the wafer W), and each spline shaft 32b, each mount 36, and each cleaning brush 2 move in a direction approaching each other, so that the cleaning surfaces of each cleaning brush 2 come into contact with the upper and lower surfaces of the wafer W, respectively, as shown in Figure 6.

[0039] 1 and 6, cleaning nozzles 11 connected to a cleaning water supply source (not shown) are disposed obliquely above and below the wafer W, respectively. Each cleaning nozzle 11 sprays a cleaning liquid (pure water) toward the center of the top and bottom surfaces of the wafer W. While the cleaning liquid is being sprayed toward the top and bottom surfaces of the wafer W from the upper and lower cleaning nozzles 11, the cases 10 of the upper and lower wafer cleaning units 1 are rotated in a horizontal plane by a rotating mechanism (not shown). The upper and lower cleaning brushes 2 rotate in the directions of the arrows in FIG. 7 and oscillate in the radial direction of the wafer W. As a result, the entire top and bottom surfaces of the wafer W are cleaned by each cleaning brush 2, respectively. Particles such as grinding debris adhering to the top and bottom surfaces of the wafer W, one side of which has been ground in the previous process, are removed (step S2 in FIG. 5). At this time, the cleaning liquid containing particles removed from the wafer W is absorbed and accumulated inside each highly porous sponge-like cleaning brush 2 by capillary action occurring in the cleaning brush 2.

[0040] Incidentally, when the cleaning brush 2 used to clean the wafer W is a cleaning brush 2A having a circular hole 2a formed in the center as shown in Fig. 3(a), the central portion where particles tend to accumulate is hollowed out, so that particles are effectively discharged from the cleaning brush 2A, and the cleaning brush 2A can be maintained in a clean state. In this case, if multiple radial grooves 2b are formed in the ring-shaped outer periphery as in the cleaning brush 2B shown in Fig. 3(b), particles are discharged from the cleaning brush 2B even more effectively.

[0041] Furthermore, instead of hollowing out the center with a circular hole, multiple radial grooves 2c can be formed on the cleaning surface, as in the cleaning brush 2C shown in Figure 3(c), or multiple grid-like grooves 2d can be formed on the cleaning surface, as in the cleaning brush 2D shown in Figure 3(d), and particles can be effectively discharged from these cleaning brushes 2C and 2D.

[0042] Thus, when the entire upper and lower surfaces of the wafer W are cleaned by the cleaning brushes 2 rotating and oscillating in the radial direction of the wafer W as described above (step S2 in FIG. 5), the number of cleanings m of the wafer W is counted (step S3 in FIG. 5), and it is determined whether the counted number of cleanings m has reached the set number of cleanings M (step S4 in FIG. 5). In this embodiment, since M=1, the determination result in step S4 is Yes, and the upper and lower cleaning brushes 2 are moved in directions separating them by the upper and lower moving units 30 shown in FIG. 2 (step S5 in FIG. 5). As shown in FIG. 4, the upper and lower cleaning brushes 2 are pivoted to sandwich the upper and lower cleaning plates 21 between them, and the upper and lower cleaning plates 21 of the brush cleaning unit 20 are set relative to the upper and lower cleaning brushes 2 (step S6 in FIG. 5), and the upper and lower cleaning plates 21 face the upper and lower cleaning brushes 2, respectively. If the number of times M for cleaning the wafer W is set to 2 or more (step S4: No), the process including cleaning the wafer W (steps S2 to S4) is repeated the set number of times M.

[0043] In this embodiment, cleaning of the wafer W is performed only once (step S4: Yes), and as described above, the upper and lower cleaning brushes 2 move in a direction separating them (step S5). When the brush cleaning unit 20 is set relative to the cleaning brushes 2 (step S6 in FIG. 5), the upper and lower cleaning brushes 2 move in a direction approaching each other (step S7 in FIG. 5), as shown in FIG. 8A. That is, when the electric motors 31 of the upper and lower moving units 30 shown in FIG. 2 are started to rotate the output shafts (motor shafts) 31a in the directions of the arrows in FIG. 8A, the ball splines 32 of the upper and lower moving units 30 rotate the cleaning brushes 2, and these rotations are converted into movements of the upper and lower cleaning brushes 2 in a direction approaching each other.

[0044] As described above, when the upper and lower cleaning brushes 2 move toward each other (step S7 in FIG. 5), it is determined whether or not each cleaning brush 2 has come into contact with the upper and lower surfaces of the wafer W (step S8 in FIG. 5). In this case, when each cleaning brush 2 comes into contact with the upper and lower surfaces of the wafer W, the rotational load of each cleaning brush 2 increases, causing a sudden increase in the load current value of each electric motor 31. This sudden increase in the load current value can be used to detect the contact of each cleaning brush 2 with the wafer W. Note that a load sensor such as a load cell can be installed in the support path of each cleaning brush 2, and the contact of each cleaning brush 2 with the wafer W can also be detected by the sudden increase in load detected by this load sensor.

[0045] 8B, when each cleaning brush 2 comes into contact with the top and bottom surfaces of the wafer W and this is detected (step S8 in FIG. 5: Yes), the deformation operation of each cleaning brush 2, which will be described below, is performed (step S9 in FIG. 5). If each cleaning brush 2 does not come into contact with the top and bottom surfaces of the wafer W (step S8: No), the processes of steps S7 to S8 are repeated until each cleaning brush 2 comes into contact with the top and bottom surfaces of the wafer W.

[0046] In the deformation operation of the cleaning brushes 2 (step S9), the upper and lower cleaning brushes 2 are in contact with the upper and lower surfaces of the wafer W as shown in FIG. 8B. The upper and lower moving units 30 shown in FIG. 2 are driven to move the upper and lower cleaning brushes 2 further in the approaching direction from the contact position as shown in FIG. 8C. These cleaning brushes 2 are pressed against the upper and lower cleaning plates 21 of the brush cleaning unit 20, elastically deforming (compressively deforming) by the amount δ shown in the figure. Then, particles that have been absorbed and accumulated in each cleaning brush 2 together with the cleaning liquid during the cleaning of the wafer W (step S2) are discharged from each cleaning brush 2 together with the cleaning liquid. The amount of deformation δ of each cleaning brush 2 at this time is set by detecting the height position of each cleaning brush 2 using the encoder 38.

[0047] Thereafter, when the output shafts (motor shafts) 31a of the electric motors 31 in the upper and lower moving units 30 rotate in the reverse direction, as shown in Fig. 8D, the moving units 30 move the cleaning brushes 2 in directions away from each other and away from the cleaning plates 21. Then, the compressively deformed cleaning brushes 2 return to their original state due to their own elastic restoring force.

[0048] During or after the deformation of each cleaning brush 2, cleaning water (pure water) is supplied to each cleaning brush 2 by the cleaning water supply means 25, so that each cleaning brush 2 is saturated with the cleaning water (step S10 in FIG. 5). That is, when one on-off valve V2 in the cleaning water supply means 25 is closed and the other on-off valve V1 is opened, cleaning water from the cleaning water supply source 28 passes through the pipe 27a and the supply paths 22a and 22b formed inside the arm 22, and is supplied to each supply groove 22c. The cleaning water supplied to each supply groove 22c is then supplied to each cleaning brush 2 through the multiple supply holes 21a formed in each of the upper and lower cleaning plates 21, so that each cleaning brush 2 is saturated with the cleaning water. When each cleaning brush 2 is saturated with the cleaning water in this way, each cleaning brush 2 is rinsed with the cleaning water.

[0049] As described above, once cleaning water is supplied to each cleaning brush 2 and each cleaning brush 2 is impregnated with the cleaning water (step S10 in FIG. 5), alkaline solution (aqueous ammonia solution) is supplied to each cleaning brush 2 by the alkaline solution supply means 26 and each cleaning brush 2 is impregnated with the cleaning water (step S11 in FIG. 5).

[0050] That is, in the alkaline solution supply means 26, when one on-off valve V1 is closed and the other on-off valve V2 is opened, the alkaline solution (aqueous ammonia solution) from the alkaline solution supply source 29 passes through the pipe 27b and the supply paths 22d and 22e formed inside the arm 22, and is supplied to each of the supply grooves 22c. The alkaline solution supplied to each of the supply grooves 22c is then supplied to each of the cleaning brushes 2 from the multiple supply holes 21a formed in each of the upper and lower cleaning plates 21, and is impregnated into each of the cleaning brushes 2. When each of the cleaning brushes 2 is impregnated with the alkaline solution in this way, particles contained in the alkaline solution are negatively charged, and therefore the particles repel each other due to repulsive force, making it difficult for the particles to adhere to each of the cleaning brushes 2.

[0051] After each cleaning brush 2 is impregnated with alkaline solution, cleaning water may be supplied again to each cleaning brush 2 to impregnate them, thereby enhancing the rinsing effect on each cleaning brush 2. When cleaning water or alkaline solution is supplied to each cleaning brush 2, ultrasonic vibrations of the cleaning water or alkaline solution may be applied by ultrasonic oscillator 23 to enhance the rinsing effect of the cleaning water on the cleaning brush 2 and the particle separation effect of the alkaline solution.

[0052] Furthermore, in this embodiment, the cleaning water supply means 25 and the alkaline solution supply means 26 are configured to supply cleaning water and alkaline solution to each cleaning brush 2 through supply paths 22a to 22e formed in the arm 22 or multiple supply holes 21a formed in each cleaning plate 21, but a configuration in which cleaning water and alkaline solution are supplied directly to each cleaning brush 2 from an external nozzle may also be used.

[0053] After the above-described deformation operation of each cleaning brush 2 (step S9 in FIG. 5), the supply of cleaning water to each cleaning brush 2 (step S10), and the supply of alkaline solution (step S11) are performed, the number of deformation operations n of the cleaning brush 2 is counted (step S12), and it is determined whether the counted number of times n has reached the initially set number of times N (step S13 in FIG. 5). In this embodiment, the number of times N to perform the deformation operation of the cleaning brush 2 is set to 10 (N=10) (see step S1 in FIG. 5), and therefore the deformation operation of the cleaning brush 2 is repeated 10 times.

[0054] Therefore, if the deformation operation of the cleaning brush 2 has been repeated 10 times (step S13: Yes), the series of cleaning operations for the wafer W and the cleaning brush 2 ends (step S14). On the other hand, if the number of deformation operations n of the cleaning brush 2 is less than 10 (step S13: No), the processes of steps S9 to S13 are repeated until the number of deformation operations n reaches 10.

[0055] As described above, in this embodiment, while supplying cleaning liquid (pure water) toward the wafer W from the pair of cleaning nozzles 11, the surface of the wafer W is cleaned by each cleaning brush 2, and then the controller 40 controls each moving unit 30 to perform a deformation operation of each cleaning brush 2, i.e., to move the cleaning brush 2 and the cleaning plate 21 closer to each other from a contact state to elastically deform the cleaning brush 2, and then to separate the cleaning brush 2 from the cleaning plate 21 to restore the cleaning brush 2 to its pre-deformation state ten times. As a result, the cleaning liquid absorbed by each cleaning brush 2 during cleaning of the wafer W is effectively discharged from each cleaning brush 2 together with particles by the pumping action caused by the deformation operation of each cleaning brush 2. This solves the problem of particles removed from the surface of the wafer W during cleaning adhering to the cleaning brush 2 itself, and provides the effect of allowing each cleaning brush 2 to sufficiently effectively clean the next wafer W.

[0056] The above effect can be further enhanced by supplying and impregnating the cleaning brush 2 with cleaning water during or after the deformation operation of the cleaning brush 2, and by supplying and impregnating the cleaning brush 2 with an alkaline solution.

[0057] In the above embodiment, pure water is used as the cleaning liquid supplied to the wafer W when cleaning the wafer W. However, a two-fluid mixture of water and air, or a liquid containing an ammonia solution may also be used as the cleaning liquid.

[0058] In addition, in the above embodiment, a configuration is adopted in which cleaning liquid is supplied from above and below the wafer W by each cleaning nozzle 11 toward the upper and lower surfaces of the wafer W, respectively, but a configuration may also be adopted in which cleaning liquid is supplied to either the upper or lower surface of the wafer W from either one of the cleaning nozzles 11.

[0059] Furthermore, in the above embodiment, the upper and lower surfaces of the wafer W are cleaned using the upper and lower cleaning brushes 2, but the present invention is also applicable to a configuration in which only one of the cleaning brushes 2 cleans either the upper or lower surface of the wafer W.

[0060] Furthermore, the present invention is not limited to the application of the above-described embodiments, and it goes without saying that various modifications are possible within the scope of the claims and the technical ideas described in the specification and drawings. [Explanation of symbols]

[0061] 1: wafer cleaning unit, 2, 2A to 2D: cleaning brush, 2a: circular hole, 2b to 2d: groove, 3: holding portion, 3A: first holding unit, 3B: second holding unit, 4: Case, 5: Output shaft (motor shaft), 6: Retaining roller, 6a: Large diameter portion of the retaining roller, 6b: Small diameter portion of retaining roller, 7: Holder, 8: Output shaft (motor shaft), 9: Retaining roller, 9a: large diameter portion of the retaining roller, 9b: small diameter portion of the retaining roller, 10: case, 11: cleaning nozzle (cleaning liquid supply means), 12: guide member, 20: brush cleaning unit, 21a: supply hole, 22: arm, 22a, 22b: supply path, 22c: supply groove, 22d, 22e: supply paths, 23: ultrasonic oscillator, 24: power source, 25: cleaning water supply means, 26: alkaline solution supply means; 27a, 27b: piping; 28: cleaning water supply source; 29: alkaline solution supply source, 30: moving unit, 31: electric motor, 31a: output shaft (motor shaft), 32: ball spline, 32a: spline nut, 32b: spline shaft, 33: holder, 34: ball bearing, 35: housing, 36: Mount, 37: Spring, 38: Encoder, 40: Controller, W: wafer, δ: cleaning brush deformation

Claims

1. a wafer cleaning unit including a holder for holding a wafer, a cleaning brush for contacting the wafer held by the holder to clean the wafer, and a cleaning liquid supply means for supplying a cleaning liquid toward the wafer; a brush cleaning unit including a cleaning plate that comes into contact with the cleaning brush to clean the cleaning brush; a moving unit that moves the cleaning brush and the cleaning plate relatively in directions toward and away from each other; A cleaning device comprising: A cleaning device characterized by having a controller that controls the moving unit to perform a deformation operation at least once, in which the cleaning brush and the cleaning plate are brought closer together from a contact state to deform the cleaning brush, and then the cleaning brush and the cleaning plate are separated to restore the cleaning brush to its pre-deformation state.

2. The brush cleaning unit includes: an alkaline solution supply means for supplying an alkaline solution to the cleaning brush; 2. The cleaning device according to claim 1, further comprising:

3. The brush cleaning unit includes:

3. The cleaning device according to claim 2, further comprising an ultrasonic oscillator for ultrasonically vibrating at least the alkaline solution.

4. The cleaning brush is 2. The cleaning device according to claim 1, wherein the cleaning device is formed in an annular shape with a circular hole formed in the center.

5. 5. The cleaning device according to claim 4, wherein a plurality of grooves are formed radially in the annular portion of the outer periphery of the cleaning brush.

6. 2. The cleaning apparatus according to claim 1, wherein a contact area of ​​said cleaning brush that contacts the surface of said wafer is formed with lattice-like or radial grooves.

7. A cleaning method carried out in the cleaning apparatus according to any one of claims 1 to 6, A cleaning method characterized in that, after cleaning a wafer with the cleaning brush, the controller controls the moving unit to bring the cleaning brush and the cleaning plate closer together from a contact state to deform the cleaning brush, and then separate the cleaning brush and the cleaning plate to restore the cleaning brush to its pre-deformation state, performing this deformation operation at least once.

8. 8. The cleaning method according to claim 7, wherein an alkaline solution is supplied to the cleaning brush during or after the deformation of the cleaning brush, thereby impregnating the cleaning brush with the alkaline solution.

9. 9. The cleaning method according to claim 8, wherein cleaning water is supplied to the cleaning brush to soak the cleaning brush in the cleaning water before the cleaning brush is soaked in the alkaline solution.

Images