Substrate cleaning apparatus and substrate cleaning method

Abstract

To efficiently clean a bottom face central area of a substrate.SOLUTION: A substrate cleaning device 1 includes: a pair of upper holding units 10A, 10B for holding the outer peripheral end portion of a substrate; a bottom face brush 51 coming into contact with the bottom face of the substrate to clean the bottom face of the substrate; and a control unit for changing push-up force that pushes a cleaning tool upward while the bottom face brush 51 cleans a bottom face central area of the substrate.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a substrate cleaning apparatus and a substrate cleaning method. [Background technology]

[0002] Substrate processing apparatuses are used to perform various processes on various substrates, such as FPD (Flat Panel Display) substrates used in liquid crystal display devices or organic EL (ElectroLuminescence) display devices, semiconductor substrates, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, photomask substrates, ceramic substrates, and solar cell substrates. Substrate cleaning apparatuses are used to clean substrates.

[0003] For example, the substrate cleaning apparatus described in Patent Document 1 includes two suction pads that hold the peripheral edge of the back surface of the wafer, a spin chuck that holds the central part of the back surface of the wafer, and a brush that cleans the back surface of the wafer. The two suction pads hold the wafer and move laterally. In this state, the central part of the back surface of the wafer is cleaned with the brush. The spin chuck then receives the wafer from the suction pads and rotates around a vertical axis (rotation axis) while holding the central part of the back surface of the wafer. In this state, the peripheral part of the back surface of the wafer is cleaned with the brush. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5904169 Summary of the Invention [Problem to be solved by the invention]

[0005] When the peripheral portion of the wafer is held by a suction pad, the center portion of the wafer is displaced downward due to its own weight, and the lower surface of the wafer becomes a curved surface. Further, when a brush is pressed against the central portion of the back surface of the wafer from below in order to bring the brush into contact with the wafer, the central portion of the wafer is displaced upward due to the load from the brush, and the lower surface of the wafer becomes a curved surface. When the upper surface of the brush is flat, the entire upper surface of the brush does not come into contact with the wafer, the contact area between the brush and the wafer becomes small, and the cleaning frequency of the region of the wafer that does not contact the brush decreases.

[0006] An object of the present invention is to provide a substrate cleaning apparatus that improves the efficiency of cleaning the central region of the lower surface of a substrate.

Means for Solving the Problems

[0007] (1) According to an aspect of the present invention, a substrate cleaning apparatus includes a substrate holding unit that holds the outer peripheral edge of a substrate, a cleaning tool that contacts the lower surface of the substrate and cleans the lower surface of the substrate, and a cleaning control unit that changes a pushing force for pushing the cleaning tool upward while the cleaning tool cleans the central region of the lower surface of the substrate. Since the pushing force for pushing the cleaning tool upward changes while the cleaning tool cleans the central region of the lower surface of the substrate, the contact surface between the cleaning tool and the substrate fluctuates due to the displacement of the substrate. Therefore, it is possible to provide a substrate cleaning apparatus that improves the efficiency of cleaning the central region of the lower surface of the substrate. So that the area in contact with the substrate on the upper surface of the cleaning tool changes Since the pushing force for pushing the cleaning tool upward changes while the cleaning tool cleans the central region of the lower surface of the substrate, the contact surface between the cleaning tool and the substrate fluctuates due to the displacement of the substrate. Therefore, it is possible to provide a substrate cleaning apparatus that improves the efficiency of cleaning the central region of the lower surface of the substrate.

[0008] (2) The cleaning control unit continuously changes the pushing force.

[0009] (3) The cleaning control unit changes the pushing force in steps when the cleaning tool does so.

[0010] (4) The substrate cleaning apparatus further includes a displacement sensor that detects the displacement of the substrate, and the cleaning control unit changes the pushing force so that the displacement of the substrate falls within a predetermined range. Therefore, the substrate can be prevented from being damaged.

[0011] (5) According to another aspect of the present invention, the substrate cleaning apparatus includes a substrate holding unit that holds the outer peripheral end portion of the substrate, a cleaning tool that contacts the lower surface of the substrate and cleans the lower surface of the substrate, and while the cleaning tool cleans the central region of the lower surface of the substrate So that the area in contact with the substrate on the upper surface of the cleaning tool changes a control unit that changes the force acting between the cleaning tool and the substrate. Therefore, since the force acting between the cleaning tool and the substrate changes while the cleaning tool cleans the central region of the lower surface of the substrate, the contact surface between the substrate and the cleaning tool can be changed while cleaning the central region of the lower surface. For this reason, a substrate cleaning apparatus that improves the cleaning efficiency of the central region of the lower surface of the substrate can be provided.

[0012] (6) The substrate cleaning apparatus further includes a displacement sensor that detects the displacement of the substrate, and the control unit changes the force acting between the cleaning tool and the substrate so that the displacement of the substrate is within a predetermined range. Therefore, the substrate can be prevented from being damaged.

[0013] (7) According to still another aspect of the present invention, a substrate cleaning method is a substrate cleaning method executed by a substrate cleaning apparatus including a substrate holding unit that holds the outer peripheral end portion of the substrate and a cleaning tool that contacts the lower surface of the substrate and cleans the lower surface of the substrate, and while the cleaning tool cleans the central region of the lower surface of the substrate So that the area in contact with the substrate on the upper surface of the cleaning tool changes includes a cleaning control step of changing the upward pushing force that pushes the cleaning tool upward.

[0014] (8) According to still another aspect of the present invention, a substrate cleaning method is a substrate cleaning method executed by a substrate cleaning apparatus including a substrate holding unit that holds the outer peripheral end portion of the substrate and a cleaning tool that contacts the lower surface of the substrate and cleans the lower surface of the substrate, and while the cleaning tool cleans the central region of the lower surface of the substrate So that the area in contact with the substrate on the upper surface of the cleaning tool changes includes a control step of changing the force acting between the cleaning tool and the substrate.

Effect of the Invention

[0015] According to the present invention, the central region of the lower surface of the substrate can be efficiently cleaned.

Brief Description of the Drawings

[0016]

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Embodiments for Carrying Out the Invention

[0017] Hereinafter, a substrate cleaning apparatus and a substrate cleaning method according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the substrate refers to a semiconductor substrate, a substrate for an FPD (Flat Panel Display) such as a liquid crystal display device or an organic EL (ElectroLuminescence) display device, a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a ceramic substrate, or a substrate for a solar cell. Further, the substrate used in the present embodiment has an outer peripheral portion that is at least partially circular. For example, the outer peripheral portion excluding the notch for positioning has a circular shape.

[0018] [First Embodiment] 1. Configuration of the Substrate Cleaning Apparatus FIG. 1 is a schematic plan view of a substrate cleaning apparatus according to an embodiment of the present invention. FIG. 2 is an external perspective view showing the internal configuration of the substrate cleaning apparatus 1. In the substrate cleaning apparatus 1 according to the present embodiment, an X direction, a Y direction, and a Z direction that are orthogonal to each other are defined in order to clarify the positional relationship. In predetermined figures after FIGS. 1 and 2, the X direction, the Y direction, and the Z direction are appropriately indicated by arrows. The X direction and the Y direction are orthogonal to each other in the horizontal plane, and the Z direction corresponds to the vertical direction.

[0019] As shown in FIG. 1, the substrate cleaning apparatus 1 includes upper holding devices 10A and 10B, a lower holding device 20, a pedestal device 30, a transfer device 40, a bottom surface cleaning device 50, a cup device 60, an upper surface cleaning device 70, an end surface cleaning device 80, and an opening / closing device 90. These components are provided in the unit housing 2. In FIG. 2, the unit housing 2 is indicated by a dotted line.

[0020] The unit housing 2 has a rectangular bottom surface 2a and four side walls 2b, 2c, 2d, and 2e extending upward from the four sides of the bottom surface 2a. The side walls 2b and 2c face each other, and the side walls 2d and 2e face each other. A rectangular opening is formed in the center of the side wall 2b. This opening is an loading / unloading opening 2x for the substrate W, and is used when loading and unloading the substrate W into and from the unit housing 2. In FIG. 2, the loading / unloading opening 2x is indicated by a thick dotted line. In the following description, the direction in the Y direction from the inside of the unit housing 2 through the loading / unloading opening 2x toward the outside of the unit housing 2 (the direction from the side wall 2c toward the side wall 2b) is referred to as the front, and the opposite direction (the direction from the side wall 2b toward the side wall 2c) is referred to as the rear.

[0021] An opening / closing device 90 is provided in the portion of the side wall 2b where the loading / unloading opening 2x is formed and in the area nearby. The opening / closing device 90 includes a shutter 91 configured to be able to open and close the loading / unloading opening 2x, and a shutter driver 92 that drives the shutter 91. In FIG. 2, the shutter 91 is indicated by a thick two-dot chain line. The shutter driver 92 drives the shutter 91 to open the loading / unloading opening 2x when the substrate W is loaded into and unloaded from the substrate cleaning apparatus 1. The shutter driver 92 also drives the shutter 91 to close the loading / unloading opening 2x when the substrate W is cleaned in the substrate cleaning apparatus 1.

[0022] A pedestal device 30 is provided in the center of the bottom surface portion 2a. The pedestal device 30 includes a linear guide 31, a movable pedestal 32, and a pedestal drive unit 33. The linear guide 31 includes two rails and is provided to extend in the Y direction from near the side wall portion 2b to near the side wall portion 2c in a plan view. The movable pedestal 32 is provided so as to be movable in the Y direction on the two rails of the linear guide 31. The pedestal drive unit 33 includes, for example, a pulse motor, and moves the movable pedestal 32 in the Y direction on the linear guide 31.

[0023] On the movable pedestal 32, a lower holding device 20 and a lower surface cleaning device 50 are provided side by side in the Y direction. The lower holding device 20 includes a suction holding portion 21 and a suction holding drive portion 22. The suction holding portion 21 is a so-called spin chuck, has a circular suction surface capable of sucking and holding the lower surface of the substrate W, and is configured to be rotatable around an axis extending in the vertical direction (axis in the Z direction). In the following description, when the substrate W is sucked and held by the suction holding portion 21, the region on the lower surface of the substrate W that the suction surface of the suction holding portion 21 should suck is called the lower surface central region. On the other hand, the region surrounding the lower surface central region on the lower surface of the substrate W is called the lower surface outer region.

[0024] The suction holding drive portion 22 includes a motor. The motor of the suction holding drive portion 22 is provided on the movable pedestal 32 such that the rotation axis projects upward. The suction holding portion 21 is attached to the upper end portion of the rotation axis of the suction holding drive portion 22. Further, a suction path for sucking and holding the substrate W in the suction holding portion 21 is formed on the rotation axis of the suction holding drive portion 22. The suction path is connected to an intake device (not shown). The suction holding drive portion 22 rotates the suction holding portion 21 around the above rotation axis.

[0025] On the movable pedestal 32, a delivery device 40 is further provided in the vicinity of the lower holding device 20. The delivery device 40 includes a plurality (three in this example) of support pins 41, a pin connecting member 42, and a pin lifting drive portion 43. The pin connecting member 42 is formed so as to surround the suction holding portion 21 in a plan view and connects the plurality of support pins 41. The plurality of support pins 41 extend upward from the pin connecting member 42 by a certain length in a state of being connected to each other by the pin connecting member 42. The pin lifting drive portion 43 raises and lowers the pin connecting member 42 on the movable pedestal 32. Thereby, the plurality of support pins 41 move up and down relative to the suction holding portion 21.

[0026] The lower surface cleaning device 50 includes a lower surface brush 51, two liquid nozzles 52, a gas ejection unit 53, a lifting support unit 54, a moving support unit 55, a lower surface brush operation drive unit 55a, a lower surface brush lifting drive unit 55b, and a lower surface brush movement drive unit 55c. The moving support unit 55 is provided so as to be movable in the Y direction relative to the lower holding device 20 within a certain area on the movable base 32. As shown in FIG. 2, the lifting support unit 54 is provided on the moving support unit 55 so as to be able to move up and down. The lifting support unit 54 has an upper surface 54u that slopes obliquely downward in a direction away from the suction holding unit 21 (rearward in this example).

[0027] 1, the lower surface brush 51 has a circular outer shape in a plan view, and is formed to be relatively large in this embodiment. Specifically, the diameter of the lower surface brush 51 is larger than the diameter of the suction surface of the suction holding unit 21, for example, 1.3 times the diameter of the suction surface of the suction holding unit 21. The diameter of the lower surface brush 51 is also larger than 1 / 3 and smaller than 1 / 2 of the diameter of the substrate W. The diameter of the substrate W is, for example, 300 mm.

[0028] The lower surface brush 51 has a cleaning surface that can come into contact with the lower surface of the substrate W. The lower surface brush 51 is attached to the upper surface 54u of the lifting support part 54 so that the cleaning surface faces upward and so that the cleaning surface can rotate around an axis that passes through the center of the cleaning surface and extends in the vertical direction.

[0029] Each of the two liquid nozzles 52 is attached to the upper surface 54u of the lifting support part 54 so as to be located near the lower surface brush 51 and so that the liquid discharge port faces upward. A lower surface cleaning liquid supply part 56 (FIG. 5) is connected to the liquid nozzle 52. The lower surface cleaning liquid supply part 56 supplies cleaning liquid to the liquid nozzle 52. When the substrate W is cleaned by the lower surface brush 51, the liquid nozzle 52 discharges the cleaning liquid supplied from the lower surface cleaning liquid supply part 56 onto the lower surface of the substrate W. In this embodiment, pure water is used as the cleaning liquid supplied to the liquid nozzle 52.

[0030] The gas ejection unit 53 is a slit-shaped gas injection nozzle having a gas ejection port extending in one direction. The gas ejection unit 53 is attached to the upper surface 54u of the lifting support unit 54 so that it is located between the lower surface brush 51 and the suction holding unit 21 in a plan view and has its gas ejection port facing upward. A jet gas supply unit 57 (FIG. 5) is connected to the gas ejection unit 53. The jet gas supply unit 57 supplies gas to the gas ejection unit 53. In this embodiment, an inert gas such as nitrogen gas is used as the gas supplied to the gas ejection unit 53. The gas ejection unit 53 ejects gas supplied from the jet gas supply unit 57 onto the lower surface of the substrate W when the lower surface brush 51 cleans the substrate W and when drying the lower surface of the substrate W, which will be described later. In this case, a band-shaped gas curtain extending in the X direction is formed between the lower surface brush 51 and the suction holding unit 21.

[0031] The lower surface brush operation drive unit 55a includes an air cylinder and an electro-pneumatic regulator that drives the air cylinder, and when the lower surface brush 51 cleans the substrate W, it drives the air cylinder by controlling the electro-pneumatic regulator, thereby controlling the upward force that presses the lower surface brush 51 against the underside of the substrate W.

[0032] The lower surface brush operation drive unit 55a further includes a motor, and when the lower surface brush 51 cleans the substrate W, the motor is driven in a state in which the lower surface brush 51 is in contact with the lower surface of the substrate W. This causes the lower surface brush 51 to rotate. The lower surface brush operation drive unit 55a will be described in detail later.

[0033] The lower surface brush lifting / lowering drive unit 55b includes a stepping motor or an air cylinder, and moves the lifting support unit 54 up and down relative to the moving support unit 55. The lower surface brush movement drive unit 55c includes a motor, and moves the moving support unit 55 in the Y direction on the movable base 32. Here, the position of the lower holding device 20 on the movable base 32 is fixed. Therefore, when the lower surface brush movement drive unit 55c moves the moving support unit 55 in the Y direction, the moving support unit 55 moves relative to the lower holding device 20. In the following description, the position of the lower surface cleaning device 50 when it is closest to the lower holding device 20 on the movable base 32 is referred to as the approach position, and the position of the lower surface cleaning device 50 when it is farthest from the lower holding device 20 on the movable base 32 is referred to as the separated position.

[0034] A cup device 60 is further provided in the center of the bottom surface portion 2a. The cup device 60 includes a cup 61 and a cup drive unit 62. The cup 61 is provided so as to surround the lower holding device 20 and the pedestal device 30 in a plan view and is capable of being raised and lowered. In FIG. 2, the cup 61 is indicated by a dotted line. The cup drive unit 62 moves the cup 61 between a lower cup position and an upper cup position depending on which portion of the underside of the substrate W is to be cleaned by the lower surface brush 51. The lower cup position is a height position where the upper end of the cup 61 is below the substrate W that is sucked and held by the suction holding unit 21. The upper cup position is a height position where the upper end of the cup 61 is above the suction holding unit 21.

[0035] A pair of upper holding devices 10A, 10B are provided at a height position above cup 61 so as to face each other across pedestal device 30 in a plan view. Upper holding device 10A includes a lower chuck 11A, an upper chuck 12A, a lower chuck driver 13A, and an upper chuck driver 14A. Upper holding device 10B includes a lower chuck 11B, an upper chuck 12B, a lower chuck driver 13B, and an upper chuck driver 14B. Upper holding devices 10A, 10B constitute a substrate alignment device of the present invention.

[0036] Figure 3 is an external perspective view of a pair of upper holding devices. In Figure 3, the lower chucks 11A and 11B are shown by thick solid lines. Also, the upper chucks 12A and 12B are shown by dotted lines. In the external perspective view of Figure 3, the magnification ratio of each part is changed from the external perspective view of Figure 2 so that the shape of the lower chucks 11A and 11B can be easily understood.

[0037] As shown in Figure 3, the lower chucks 11A and 11B are symmetrically arranged with respect to a vertical plane extending in the Y direction (front-rear direction) passing through the center of the suction holding portion 21 in a plan view, and are provided so as to be movable in the X direction within a common horizontal plane. Each of the lower chucks 11A and 11B has two support pieces 200. An inclined support surface 201 and a movement restricting surface 202 are provided on each support piece 200.

[0038] In the lower chuck 11A, the inclined support surface 201 of each support piece 200 is formed so as to be able to support the outer peripheral end portion of the substrate W from below and extend obliquely downward toward the lower chuck 11B. The movement restricting surface 202 extends upward a certain distance from the upper end portion of the inclined support surface 201 and forms a step at the upper end portion of the lower chuck 11A. On the other hand, in the lower chuck 11B, the inclined support surface 201 of each support piece 200 is formed so as to be able to support the outer peripheral end portion of the substrate W from below and extend obliquely downward toward the lower chuck 11A. The movement restricting surface 202 extends upward a certain distance from the upper end portion of the inclined support surface 201 and forms a step at the upper end portion of the lower chuck 11B.

[0039] The lower chuck drivers 13A and 13B include air cylinders or motors as actuators. The lower chuck drivers 13A and 13B move the lower chucks 11A and 11B so that the lower chucks 11A and 11B approach each other or move away from each other. Here, if the target positions of the lower chucks 11A and 11B in the X direction are predetermined, the lower chuck drivers 13A and 13B can individually adjust the positions of the lower chucks 11A and 11B in the X direction based on the target position information. For example, by making the distance between the lower chucks 11A and 11B smaller than the outer diameter of the substrate W, the substrate W can be placed on the multiple inclined support surfaces 201 of the lower chucks 11A and 11B. In this case, the outer peripheral edge of the substrate W is supported by each inclined support surface 201.

[0040] Figure 4 is an external perspective view of the upper chucks 12A and 12B shown in Figures 1 and 2. In Figure 4, the upper chucks 12A and 12B are indicated by thick solid lines. The lower chucks 11A and 11B are indicated by dotted lines. In the external perspective view of Figure 4, the scale of each part has been changed from that of the external perspective view of Figure 2 so that the shapes of the upper chucks 12A and 12B can be more easily understood.

[0041] 4, like the lower chucks 11A and 11B, the upper chucks 12A and 12B are disposed symmetrically with respect to a vertical plane extending in the Y direction (front-rear direction) through the center of the suction holding portion 21 in a plan view, and are provided so as to be movable in the X direction within a common horizontal plane. Each of the upper chucks 12A and 12B has two holding pieces 300. Each holding piece 300 has an abutment surface 301 and a protrusion 302.

[0042] In the upper chuck 12A, the contact surface 301 of each holding piece 300 is formed at the lower part of the tip of the holding piece 300 so as to face the upper chuck 12B and is orthogonal to the X direction. The protruding portion 302 is formed so as to protrude a predetermined distance from the upper end of the contact surface 301 toward the upper chuck 12B. On the other hand, in the upper chuck 12B, the contact surface 301 of each holding piece 300 is formed at the lower part of the tip of the holding piece 300 so as to face the upper chuck 12A and is orthogonal to the X direction. The protruding portion 302 is formed so as to protrude a predetermined distance from the upper end of the contact surface 301 toward the upper chuck 12A.

[0043] The upper chuck driving parts 14A and 14B include an air cylinder or a motor as an actuator. The upper chuck driving parts 14A and 14B move the upper chucks 12A and 12B so that the upper chucks 12A and 12B approach each other or move away from each other. Here, when the target positions of the upper chucks 12A and 12B in the X direction are predetermined, the upper chuck driving parts 14A and 14B can individually adjust the positions of the upper chucks 12A and 12B in the X direction based on the information of the target positions.

[0044] In the above upper holding devices 10A and 10B, the upper chucks 12A and 12B are moved toward the outer peripheral end portions of the substrate W supported by the lower chucks 11A and 11B. By the two contact surfaces 301 of the upper chuck 12A and the two contact surfaces 301 of the upper chuck 12B contacting a plurality of portions of the outer peripheral end portion of the substrate W, the outer peripheral end portion of the substrate W is held and the substrate W is firmly fixed.

[0045] In this embodiment, the upper chuck driver 14B adjusts the distance between the upper chuck 12A and the upper chuck 12B so that the pressing force with which the two contact surfaces 301 of the upper chuck 12A and the two contact surfaces 301 of the upper chuck 12B press the substrate W is constant. A pressure sensor is provided on either the two contact surfaces 301 of the upper chuck 12A or the two contact surfaces 301 of the upper chuck 12B. The upper chuck driver 14B adjusts the distance between the upper chuck 12A and the upper chuck 12B so that the output value of the pressure sensor becomes a predetermined target value. Therefore, the pressing force with which the pair of upper holding devices 10A, 10B hold the substrate W is constant.

[0046] 1, an upper surface cleaning device 70 is provided on one side of the cup 61 so as to be located near the upper holding device 10B in a plan view. The upper surface cleaning device 70 includes a rotary support shaft 71, an arm 72, a spray nozzle 73, and an upper surface cleaning drive unit 74.

[0047] The rotation support shaft 71 is supported on the bottom surface portion 2a by an upper surface cleaning drive unit 74 so as to extend in the vertical direction and to be movable up and down and rotatable. As shown in Fig. 2, the arm 72 is provided at a position above the upper holding device 10B and extends horizontally from the upper end of the rotation support shaft 71. A spray nozzle 73 is attached to the tip of the arm 72.

[0048] An upper surface cleaning fluid supply unit 75 (FIG. 5) is connected to the spray nozzle 73. The upper surface cleaning fluid supply unit 75 supplies a cleaning liquid and a gas to the spray nozzle 73. In this embodiment, pure water is used as the cleaning liquid supplied to the spray nozzle 73, and an inert gas such as nitrogen gas is used as the gas supplied to the spray nozzle 73. When cleaning the upper surface of the substrate W, the spray nozzle 73 mixes the cleaning liquid and the gas supplied from the upper surface cleaning fluid supply unit 75 to generate a mixed fluid, and sprays the generated mixed fluid downward.

[0049] The upper surface cleaning drive unit 74 includes one or more pulse motors, air cylinders, etc., and raises and lowers the rotary support shaft 71 and rotates the rotary support shaft 71. According to the above configuration, by moving the spray nozzle 73 in an arc over the upper surface of the substrate W that is suction-held and rotated by the suction holding unit 21, it is possible to clean the entire upper surface of the substrate W.

[0050] 1, an edge cleaning device 80 is provided on the other side of cup 61 so as to be located near upper holding device 10A in a plan view. Edge cleaning device 80 includes a rotary support shaft 81, an arm 82, a bevel brush 83, and a bevel brush driving unit 84.

[0051] The rotation support shaft 81 is supported by a bevel brush drive unit 84 on the bottom surface portion 2a so as to extend in the vertical direction and to be movable up and down and rotatable. As shown in Fig. 2, the arm 82 is provided at a position above the upper holding device 10A and extends horizontally from the upper end of the rotation support shaft 81. A bevel brush 83 is provided at the tip of the arm 82 so as to protrude downward and to be rotatable around an axis extending in the vertical direction.

[0052] The upper half of the bevel brush 83 has an inverted truncated cone shape, and the lower half has a truncated cone shape. With this bevel brush 83, the outer peripheral edge of the substrate W can be cleaned at the central portion in the vertical direction of the outer peripheral surface.

[0053] The bevel brush driving unit 84 includes one or more pulse motors, air cylinders, etc., and raises and lowers the rotary support shaft 81 and rotates the rotary support shaft 81. According to the above configuration, by bringing the central portion of the outer circumferential surface of the bevel brush 83 into contact with the outer circumferential edge of the substrate W that is being sucked and held by the sucking and holding unit 21 and rotated, the entire outer circumferential edge of the substrate W can be cleaned.

[0054] Here, the bevel brush driving unit 84 further includes a motor built in the arm 82. The motor rotates a bevel brush 83 provided at the tip of the arm 82 around the axis in the vertical direction. Therefore, when cleaning the outer peripheral end of the substrate W, the rotation of the bevel brush 83 improves the cleaning power of the bevel brush 83 at the outer peripheral end of the substrate W.

[0055] FIG. 5 is a block diagram showing the configuration of the control system of the substrate cleaning apparatus 1. The control device 9 in FIG. 5 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a storage device. The RAM is used as a work area for the CPU. The ROM stores the system program. The storage device stores the control program.

[0056] As shown in FIG. 5, the control device 9 includes, as functional units, a chuck control unit 9A, a suction control unit 9B, a pedestal control unit 9C, a delivery control unit 9D, a bottom cleaning control unit 9E, a cup control unit 9F, an upper cleaning control unit 9G, a bevel cleaning control unit 9H, and a loading / unloading control unit 9I. By the CPU executing the substrate cleaning program stored in the storage device on the RAM, the functional units of the control device 9 are realized. Part or all of the functional units of the control device 9 may be realized by hardware such as an electronic circuit.

[0057] The chuck control unit 9A controls the lower chuck driving units 13A, 13B and the upper chuck driving units 14A, 14B in order to receive the substrate W carried into the substrate cleaning apparatus 1 and hold it at a position above the suction holding unit 21. The suction control unit 9B controls the suction holding driving unit 22 in order to suction-hold the substrate W by the suction holding unit 21 and rotate the suction-held substrate W.

[0058] The pedestal control unit 9C controls the pedestal driving unit 33 in order to move the movable pedestal 32 with respect to the substrate W held by the upper holding devices 10A, 10B. The delivery control unit 9D controls the pin lifting driving unit 43 in order to move the substrate W between the height position of the substrate W held by the upper holding devices 10A, 10B and the height position of the substrate W held by the suction holding unit 21.

[0059] Next, the lower surface cleaning control unit 9E controls the lower surface brush operation drive unit 55a, the lower surface brush lifting drive unit 55b, the lower surface brush movement drive unit 55c, the lower surface cleaning liquid supply unit 56, and the ejected gas supply unit 57 to clean the lower surface of the substrate W. The cup control unit 9F controls the cup drive unit 62 to receive the cleaning liquid scattered from the substrate W during the cleaning of the substrate W held by the adsorption holding unit 21 with the cup 61.

[0060] The upper surface cleaning control unit 9G controls the upper surface cleaning drive unit 74 and the upper surface cleaning fluid supply unit 75 to clean the upper surface of the substrate W held by the adsorption holding unit 21. The bevel cleaning control unit 9H controls the bevel brush drive unit 84 to clean the outer peripheral end portion of the substrate W held by the adsorption holding unit 21. The loading / unloading control unit 9I controls the shutter drive unit 92 to open and close the loading / unloading port 2x of the unit housing 2 when loading and unloading the substrate W in the substrate cleaning apparatus 1.

[0061] 2. Schematic Operation during Cleaning of the Central Region on the Lower Surface of the Substrate Cleaning Apparatus FIG. 6 is a schematic diagram for explaining the schematic operation of the substrate cleaning apparatus 1. In FIG. 6, a plan view of the substrate cleaning apparatus 1 is shown in the upper row. Also, a side view of the lower holding device 20 and its peripheral portion as viewed along the X direction is shown in the lower row. The side view in the lower row corresponds to the side view taken along line A - A in FIG. 1. Note that, in order to facilitate the understanding of the shapes and operating states of the respective components in the substrate cleaning apparatus 1, the magnification ratios of some components are different between the upper plan view and the lower side view. Also, the cup 61 is shown by a two - dot chain line, and the outer shape of the substrate W is shown by a thick one - dot chain line.

[0062] Referring to FIG. 6, as shown by the thick solid arrow a5, the lifting support portion 54 rises so that the cleaning surface of the lower surface brush 51 contacts the central region on the lower surface of the substrate W. Also, as shown by the thick solid arrow a6, the lower surface brush 51 rotates (spins) around the axis in the vertical direction. Thereby, the contaminants adhering to the central region on the lower surface of the substrate W are physically peeled off by the lower surface brush 51.

[0063] The lower part of FIG. 6 shows an enlarged side view of the portion where the lower-surface brush 51 contacts the underside of the substrate W in a bubble. As shown in the bubble, with the lower-surface brush 51 in contact with the substrate W, the liquid nozzle 52 and the gas ejection unit 53 are held in positions close to the underside of the substrate W. At this time, the liquid nozzle 52 ejects cleaning liquid toward the underside of the substrate W at a position near the lower-surface brush 51, as indicated by the outline arrow a51. As a result, the cleaning liquid supplied from the liquid nozzle 52 to the underside of the substrate W is guided to the contact portion between the lower-surface brush 51 and the substrate W, and contaminants removed from the back surface of the substrate W by the lower-surface brush 51 are washed away by the cleaning liquid. In this way, in the lower-surface cleaning device 50, the liquid nozzle 52 and the lower-surface brush 51 are attached to the lifting support unit 54. This allows the cleaning liquid to be efficiently supplied to the portion of the underside of the substrate W being cleaned by the lower-surface brush 51. This reduces the amount of cleaning liquid consumed and suppresses excessive splashing of the cleaning liquid.

[0064] 6, when cleaning of the central region of the lower surface of the substrate W is completed, the rotation of the lower surface brush 51 is stopped, and the lifting support part 54 is lowered so that the cleaning surface of the lower surface brush 51 is spaced a predetermined distance from the substrate W. In addition, the discharge of the cleaning liquid from the liquid nozzle 52 onto the substrate W is stopped. At this time, the spray of gas from the gas ejection part 53 onto the substrate W continues.

[0065] 3. Controlling the lifting force of the lower brush The lower surface brush operation drive unit 55a varies the force that pushes the lower surface brush 51 upward on the lower surface of the substrate W while the lower surface brush 51 is cleaning the central region of the lower surface of the substrate W. Hereinafter, the force that pushes the lower surface brush 51 upward is referred to as the pushing force.

[0066] In this embodiment, the substrate W is firmly fixed by a pair of upper holding devices 10A and 10B that are arranged to face each other across the substrate W in a plan view and sandwich the substrate W. Since the substrate W has a predetermined weight, the substrate W is curved by gravity. In this case, the displacement downward of the central portion of the substrate W becomes the maximum. Further, a pressing force with which the pair of upper holding devices 10A and 10B hold the substrate W is applied to the substrate W. Therefore, the amount of displacement downward of the central portion of the substrate W is determined by the resultant force of the gravity applied to the substrate W and the pressing force that the substrate W receives from the upper holding devices 10A and 10B. When the substrate W is deformed into a downward protruding shape by the pressing force received from the upper holding devices 10A and 10B, a force in the downward direction acts on the central portion of the substrate W. On the other hand, when the substrate W is deformed into an upward protruding shape by the pressing force received from the upper holding devices 10A and 10B, a force in the upward direction acts on the central portion of the substrate W. In this embodiment, the pressing force that the substrate W receives from the upper holding devices 10A and 10B is constant. to While the lower surface brush 51 is cleaning the central region of the lower surface of the substrate W, the lower surface brush 51 is pressed against the lower surface of the substrate W. At this time, whether or not the central portion of the substrate W is displaced is determined by the resultant force of the gravity applied to the substrate W and the pressing force applied to the substrate W by the pair of upper holding devices 10A and 10B, and the upward pressing force applied to the lower surface brush 51. By varying the upward pressing force by the lower surface brush operation driving unit 55a, the displacement of the central portion of the substrate W is adjusted. Here, the amount of displacement of the substrate W is indicated by the vertical distance between the position of the central portion of the substrate W and the reference position, with the position where the substrate W is held by the pair of upper holding devices 10A and 10B as the reference position. The amount of displacement is set such that the downward direction from the reference position is a negative value and the upward direction is a positive value. Also, the maximum amount of displacement allowed for the central portion of the substrate W to be displaced to the positive side among the amounts of displacement is referred to as the upper limit value, and the minimum amount of displacement allowed for the central portion of the substrate W to be displaced to the negative side is referred to as the lower limit value.

[0067]

[0068] ​FIG. 7 is a diagram schematically showing the positional relationship between the substrate and the lower surface brush in a state where the substrate is not displaced. FIG. 8 is a diagram showing an example of the contact surface between the substrate and the lower surface brush in a state where the substrate is not displaced. In FIG. 7, the region where the substrate W and the lower surface brush 51 are in contact is indicated by a thick line, and in FIG. 8, the region where the substrate W and the lower surface brush 51 are in contact is indicated by hatching.

[0069] Referring to FIGS. 7 and 8, the central portion of the substrate W is the same as the reference position. In this case, the displacement amount of the substrate W is zero, the substrate W is substantially horizontal over the entire surface, and the lower surface central region BC of the substrate W becomes a plane. On the other hand, the upper surface of the lower surface brush 51 is substantially horizontal. For this reason, the lower surface brush 51 and the substrate W are in contact with each other in the entire region R1 corresponding to the entire lower surface central region BC. In this case, the force acting between the lower surface brush 51 and the lower surface central region BC is evenly distributed over the entire region R1.

[0070] FIG. 9 is a diagram schematically showing the positional relationship between the substrate and the lower surface brush in a state where the substrate is displaced to the minus side. FIG. 10 is a diagram showing an example of the contact surface between the substrate and the lower surface brush in a state where the substrate is displaced to the minus side. In FIG. 9, the region where the substrate W and the lower surface brush 51 are in contact is indicated by a thick line, and in FIG. 10, the region where the substrate W and the lower surface brush 51 are in contact is indicated by hatching.

[0071] Referring to FIG. 9, when the center of the substrate W is displaced to the minus side from the reference position, the substrate W has a downward protruding shape, and the lower surface central region BC becomes a curved surface. On the other hand, the upper surface of the lower surface brush 51 is substantially horizontal. For this reason, the entire upper surface of the lower surface brush 51 does not come into contact with the substrate W. Referring to FIG. 10, the lower surface brush 51 and the substrate W are in contact with each other in a central region R2 that is circular or elliptical and has a diameter smaller than that of the lower surface central region BC and includes the central portion of the substrate W in the lower surface central region BC.

[0072] Fig. 11 is a diagram showing a schematic diagram of the positional relationship between the substrate W and the lower-surface brush when the substrate is displaced to the plus side. Fig. 12 is a diagram showing an example of the contact surface between the substrate W and the lower-surface brush when the substrate is displaced to the plus side. In Fig. 11, the area where the substrate W and the lower-surface brush 51 contact is shown by a thick line, and in Fig. 12, the area where the substrate W and the lower-surface brush 51 contact is shown by hatching.

[0073] 11, when the center of the substrate W is displaced to the positive side, the lower surface central region becomes convex upward, and the lower surface central region BC becomes curved. On the other hand, the upper surface of the lower surface brush 51 is approximately horizontal. Therefore, the entire upper surface of the lower surface brush 51 does not come into contact with the substrate W. Referring to FIG. 12, the lower surface brush 51 and the substrate W come into contact with each other in an annular region R3 of the lower surface central region BC that includes the outer periphery and excludes the center portion of the substrate W.

[0074] FIG. 13 is a time chart showing an example of changes in the upward pushing force. In the time chart of FIG. 13, the vertical axis represents the upward pushing force, and the horizontal axis represents time. Referring to FIG. 13, at time t0, before the lower surface brush 51 starts cleaning the lower surface central region BC of the substrate W, the lower surface brush operation drive unit 55a does not apply force to the lower surface brush 51. At time t1, when the lower surface brush 51 starts cleaning the lower surface central region BC of the substrate W, the lower surface brush operation drive unit 55a controls the electropneumatic regulator to apply an upward pushing force f2 to the lower surface brush 51. The upward pushing force f2 is determined by the resultant force of the gravity of the substrate W and the pressing forces of the pair of upper holding devices 10A, 10B holding the substrate W. Specifically, the upward pushing force f2 is predetermined to a value that can maintain a state in which the central portion of the substrate W is displaced toward the negative side and the displacement amount of the substrate W is at a lower limit value. Therefore, at time t1, the central portion of the substrate W is displaced to the minus side, as shown in FIGS.

[0075] Then, at time t2, the lower surface brush operation drive unit 55a controls the pneumatic regulator to apply an upward pushing force f1 to the lower surface brush 51. The upward pushing force f1 is a value larger than the upward pushing force f2. The pressing force by which the pair of upper holding devices 10A and 10B hold the substrate W acts in the direction of displacing the central portion of the substrate W to the minus side in a state where the central portion of the substrate W is displaced to the minus side. Since the upward pushing force f1 is larger than the upward pushing force f2, after time t2, the lower surface brush 51 rises, and the central portion of the substrate W is pushed upward.

[0076] Time t3 is the time when half of the cleaning period, which is predetermined as the period for cleaning the central region BC of the lower surface of the substrate W by the lower surface brush 51, has elapsed. The upward pushing force f1 is determined so that the center of the substrate W becomes the reference position during the period from time t2 to time t3.

[0077] At time t3 when the center of the substrate W reaches the reference position, the lower surface brush operation drive unit 55a controls the pneumatic regulator to apply an upward pushing force f3 to the lower surface brush 51. The pressing force by which the pair of upper holding devices 10A and 10B hold the substrate W acts in the direction of displacing the central portion of the substrate W to the plus side in a state where the central portion of the substrate W is displaced to the plus side. For this reason, the upward pushing force f3 is a value smaller than the upward pushing force f2, but after time t3, the lower surface brush 51 rises, and the central portion of the substrate W is pushed upward.

[0078] Time t4 is the time when the cleaning period, which is predetermined as the period for cleaning the central region BC of the lower surface of the substrate W by the lower surface brush 51, has elapsed. The upward pushing force f3 is determined so that the central portion of the substrate W is displaced to the plus side and the displacement amount of the substrate W reaches the upper limit value during the period from time t3 to time t4. At time t4, as shown in FIGS. 11 and 12, the central portion of the substrate W is in a state of being displaced to the plus side. At time t4, the lower surface brush operation drive unit 55a stops controlling the pneumatic regulator.

[0079] At time t2, as shown in FIGS. 9 and 10, in the central region R2 within the central region BC on the lower surface of the substrate W, the lower surface brush 51 contacts the substrate W. Accordingly, the central region R2 of the substrate W is cleaned.

[0080] At time t3, in the entire region R1 within the central region BC on the lower surface of the substrate W, the lower surface brush 51 contacts the substrate W. Accordingly, at time t3, the entire region R1 (central region BC on the lower surface) of the substrate W is cleaned. During the period from time t2 to time t3, the portion where the lower surface brush 51 and the substrate W are in contact gradually spreads from the central region R2 to the entire region R1.

[0081] At time t4, in the annular region R3 within the central region BC on the lower surface of the substrate W, the lower surface brush 51 contacts the substrate W. Accordingly, the annular region R3 of the substrate W is cleaned. During the period from time t3 to time t4, the portion where the lower surface brush 51 and the substrate W are in contact gradually becomes narrower from the entire region R1 to the annular region R3.

[0082] FIG. 14 is a flowchart showing an example of the flow of the pushing force control process. The pushing force control process is a process executed by the control device 9. Referring to FIG. 14, the control device 9 controls the lower surface brush operation driving unit 55a to push up the lower surface brush 51 with a pushing force f2 (step S01). At this stage, as shown in FIGS. 9 and 10, in the central region R2 within the central region BC on the lower surface of the substrate W, the lower surface brush 51 contacts the substrate W. In the next step S02, the control device 9 pushes up the lower surface brush 51 with a pushing force f1 and advances the process to step S03. The pushing force f1 is a value larger than the pushing force f2. For this reason, the lower surface brush 51 rises, and the center of the substrate W is pushed upward by the lower surface brush 51.

[0083] In step S03, it is determined whether or not a predetermined time has elapsed since the upward pressing of the lower surface brush 51 was started with the upward pressing force f1. The predetermined time is the time for the central portion of the substrate W to move to the reference position. The process waits until the predetermined time elapses (NO in step S03), and if the predetermined time has elapsed (YES in step S03), the process proceeds to step S04. When a displacement sensor for detecting the displacement of the central portion of the substrate W is provided, the displacement of the central portion of the substrate W may be detected based on the output of the displacement sensor. Immediately before the process proceeds to step S04, as shown in FIGS. 7 and 8, the central region BC on the lower surface of the substrate W is located at the reference position, and the entire region R1 of the substrate W is in contact with the lower surface brush 51.

[0084] In step S04, the control device 9 pushes up the lower surface brush 51 with the upward pressing force f3 and advances the process to step S05. For this reason, the lower surface brush 51 rises, and the central portion of the substrate W is pushed upward by the lower surface brush 51. At the stage where the process proceeds to step S04, the central portion of the substrate W is displaced to the plus side. The pressing force applied to the substrate W by the pair of upper holding devices 10A and 10B acts in the direction of displacing the central portion of the substrate W to the plus side in a state where the central portion of the substrate W is displaced to the plus side. For this reason, the upward pressing force f3 is smaller than the upward pressing force f2.

[0085] In step S05, it is determined whether or not the cleaning period has ended. The process waits until the cleaning period ends (NO in step S05), and if the cleaning period has ended (YES in step S05), the process ends.

[0086] In the present embodiment, an example in which the central portion of the substrate W is displaced from the minus side to the plus side has been shown, but the central portion of the substrate W may be displaced from the plus side to the minus side.

[0087] 4. Modification Example of Upward Pressing Force Control FIG. 15 is a time chart showing an example of changes in the upward pressing force in the modification example. In the time chart of FIG. 15, the vertical axis represents the upward pressing force, and the horizontal axis represents time.

[0088] Referring to FIG. 15, at time t0 before the cleaning of the central region BC on the lower surface of the substrate W by the lower surface brush 51 is started, the lower surface brush operation driving unit 55a does not apply an upward pushing force to the lower surface brush 51. At time t1 when the cleaning of the central region BC on the lower surface of the substrate W by the lower surface brush 51 is started, the lower surface brush operation driving unit 55a controls the pneumatic regulator to apply an upward pushing force f2 to the lower surface brush 51. Then, in the period T1 from time t1 to time t2, the pneumatic regulator is controlled to apply an upward pushing force f1 to the lower surface brush 51. The upward pushing force f2 is determined by the resultant force of the gravity of the substrate W and the pressing force with which the pair of upper holding devices 10A and 10B hold the substrate W. Specifically, the upward pushing force f2 is predetermined to be a value that maintains the displacement amount of the central portion of the substrate W at the lower limit value. Therefore, in the period T1, as shown in FIGS. 9 and 10, the lower surface brush 51 and the substrate W are in contact with each other with the displacement amount of the substrate W at the lower limit value. For this reason, in the period T1, in the central region R2 within the central region BC on the lower surface of the substrate W, the lower surface brush 51 contacts the substrate W. Therefore, the central region R2 of the substrate W is cleaned.

[0089] From time t2 to time t3, the lower surface brush operation driving unit 55a controls the pneumatic regulator to apply an upward pushing force f1 to the lower surface brush 51. The upward pushing force f1 is a value larger than the upward pushing force f2. The pressing force applied by the pair of upper holding devices 10A and 10B to the substrate W acts in the direction of displacing the central portion of the substrate W to the minus side when the central portion of the substrate W is displaced to the minus side. Since the upward pushing force f1 is larger than the upward pushing force f2, in the period from time t2 to time t3, the lower surface brush 51 rises and the central portion of the substrate W is pushed upward. The upward pushing force f1 is determined so that the central portion of the substrate W becomes the reference position in the period from time t2 to time t3.

[0090] Then, in a period T2 from time t3 to time t4, the electro-pneumatic regulator is controlled to apply an upward pushing force f4 to the lower surface brush 51. The pressing force applied by the pair of upper holding devices 10A and 10B to the substrate W does not act in a direction to displace the central portion of the substrate W in the vertical direction when the central portion of the substrate W is in the reference position. For this reason, the upward pushing force f4 is a value smaller than the upward pushing force f2. Specifically, as shown in FIGS. 7 and 8, the upward pushing force f4 is predetermined to be a value that maintains the central portion of the substrate W at the reference position. Therefore, in the period T2, as shown in FIGS. 7 and 8, the central portion of the substrate W does not displace. For this reason, in the entire region R1 within the lower surface central region BC of the substrate W in the period T2, the lower surface brush 51 contacts the substrate W. Therefore, the entire region R1 of the substrate W is cleaned.

[0091] From time t4 to time t5, the lower surface brush operation driving unit 55a controls the electro-pneumatic regulator to apply an upward pushing force f3 to the lower surface brush 51. The upward pushing force f3 is a value larger than the upward pushing force f4. The pressing force applied by the pair of upper holding devices 10A and 10B to the substrate W does not act in a direction to displace the central portion of the substrate W when the central portion of the substrate W is not displaced either to the minus side or the plus side. Since the upward pushing force f3 is larger than the upward pushing force f4, in the period from time t4 to time t5, the lower surface brush 51 rises and the central portion of the substrate W is pushed upward. In the period from time t4 to time t5, the upward pushing force f3 is determined such that the central portion of the substrate W is displaced to the plus side and the displacement amount of the substrate W reaches the upper limit value.

[0092] Then, in the period T3 from time point t5 to time point t6, the electro-pneumatic regulator is controlled to apply an upward force f5 to the lower surface brush 51. The pressing force applied by the pair of upper holding devices 10A and 10B to the substrate W acts in the direction of displacing the central portion of the substrate W to the positive side in a state where the central portion of the substrate W is displaced to the positive side. For this reason, the upward force f5 is a value smaller than the upward force f4. Specifically, the upward force f5 is predetermined to be a value that maintains the state where the displacement amount of the central portion of the substrate W is at the upper limit value. Therefore, in the period T3, as shown in FIGS. 11 and 12, the lower surface brush 51 and the substrate W come into contact with each other in a state where the displacement amount of the substrate W is at the upper limit value. For this reason, in the period T3, in the annular region R3 within the central region BC on the lower surface of the substrate W, the lower surface brush 51 comes into contact with the substrate W. Therefore, the annular region R3 of the substrate W is cleaned. At time point t6, the lower surface brush operation driving unit 55a stops the control of the electro-pneumatic regulator.

[0093] In the period T1, the lower surface brush 51 is pushed up by the upward force f2. In the period T2, the lower surface brush 51 is pushed up by the upward force f4. In the period T3, the lower surface brush 51 is pushed up by the upward force f5. Since the upward force f2, the upward force f4, and the upward force f5 are different from each other, the periods T1, T2, and T3 may be made different according to the upward force f2, the upward force f4, and the upward force f5. For example, the period can be determined based on the upward force per unit area obtained from the upward force and the contact area.

[0094] 16 is a flowchart showing an example of the flow of the upward force control process in the modified example. Referring to FIG. 16, the control device 9 controls the lower surface brush operation drive unit 55a to push up the lower surface brush 51 with an upward force f2, thereby cleaning the central region (step S11). In this case, the central region R2 is cleaned when the displacement amount of the substrate W is at the lower limit. In the next step S12, it is determined whether or not the period T1 has elapsed. The period T1 is a period predetermined as a period for cleaning the central region R2. A standby state is entered until the elapsed time from the start of cleaning of the central region R2 reaches the period T1 (NO in step S12), and once the period T1 has elapsed (YES in step S15), the process proceeds to step S13.

[0095] In step S13, the lower surface brush 51 is pushed up with an upward force f2, and the process proceeds to step S14. This causes the lower surface brush 51 to rise, and the central portion of the substrate W is raised to the reference position. In step S14, the lower surface brush 51 is pushed up with an upward force f1, the entire region R1 is cleaned, and the process proceeds to step S15. In step S15, it is determined whether or not the period T2 has elapsed. The period T2 is a period that is predetermined as the period for cleaning the entire region R1. A standby state is entered until the elapsed time from the start of cleaning of the entire region R1 reaches the period T2 (NO in step S15), and once the period T2 has elapsed (YES in step S15), the process proceeds to step S13.

[0096] In step S16, the lower surface brush 51 is pushed up with an upward force f3, and the process proceeds to step S17. This causes the lower surface brush 51 to rise, and the displacement amount of the substrate W reaches its upper limit. In step S17, the lower surface brush 51 is pushed up with an upward force f5, the annular region R3 is cleaned, and the process proceeds to step S18. In step S18, it is determined whether or not the period T3 has elapsed. The period T3 is a period that has been predetermined as the period for cleaning the annular region R3. A standby state is entered until the elapsed time since cleaning of the annular region R3 begins reaches the period T3 (NO in step S17), and once the period T3 has elapsed (YES in step S17), the process ends.

[0097] 5. Second Modification of Pushing Force Control The continuous variation of the pushing force applied to the bottom brush may be repeated. The cycle of the change in the pushing force shown in FIG. 13 can be repeated a plurality of times. Further, although the cycle of the change in the pushing force shown in FIG. 13 shows the cycle of cleaning the central region R2, the entire region R1, and the annular region R3 of the substrate W in this order, it may be the cycle of cleaning the annular region R3, the entire region R1, and the central region R2 of the substrate W in this order.

[0098] Also, the stepwise variation of the pushing force applied to the bottom brush may be repeated. The cycle of the change in the pushing force shown in FIG. 15 can be repeated a plurality of times. Further, although the cycle of the change in the pushing force shown in FIG. 15 shows the cycle of cleaning the central region R2, the entire region R1, and the annular region R3 of the substrate W in this order, it may be the cycle of cleaning the annular region R3, the entire region R1, and the central region R2 of the substrate W in this order.

[0099] 6. Effects In the substrate cleaning apparatus 1 according to the first embodiment, since the pushing force for pushing the bottom brush 51 upward is changed while the bottom brush 51 is cleaning the central region BC on the bottom surface of the substrate W, the contact surface between the bottom brush 51 and the substrate W varies due to the displacement of the substrate W.

[0100] Also, since the pushing force of the bottom brush 51 changes continuously, the speed at which the substrate W is displaced can be reduced.

[0101] In the modification, since the pushing force of the bottom brush 51 changes stepwise, the central region R2, the entire region R1, and the annular region R3 of the substrate W can be cleaned separately. For this reason, the cleaning time for each of the central region R2, the entire region R1, and the annular region R3 can be adjusted based on the magnitude of the force acting between the bottom brush 51 and the substrate W and the area of the contact surface between the bottom brush 51 and the substrate W. Therefore, the central region BC on the bottom surface can be cleaned efficiently.

[0102] [Second Embodiment] 1. Configuration of the substrate cleaning apparatus in the second embodiment FIG. 17 is an external perspective view showing the internal configuration of the substrate cleaning apparatus 1 in the second embodiment. Referring to FIG. 17, in the substrate cleaning apparatus 1 in the second embodiment, a displacement sensor 95 is added to the substrate cleaning apparatus 1 shown in FIG. 2. The displacement sensor 95 is provided vertically upward from the center of the substrate W held by the pair of upper holding devices 10A and 10B. The displacement sensor 95 measures the distance to the central portion of the substrate W held by the pair of upper holding devices 10A and 10B. Therefore, the displacement sensor 95 detects the displacement of the central portion of the substrate W in the vertical direction (Z direction). Here, the displacement amount of the substrate W is indicated by the vertical distance between the position of the central portion of the substrate W and the reference position, with the position where the substrate W is held by the upper holding devices 10A and 10B as the reference position. The displacement amount is set such that the downward direction from the reference position is a negative value and the upward direction is a positive value. Also, the maximum displacement amount allowed for the central portion of the substrate W to be displaced to the positive side among the displacement amounts is referred to as the upper limit value, and the minimum displacement amount allowed for the central portion of the substrate W to be displaced to the negative side is referred to as the lower limit value.

[0103] The substrate cleaning apparatus 1 in the second embodiment varies the pushing force based on the output of the displacement sensor 95. Specifically, the pushing force is adjusted so that the displacement of the central portion of the substrate W falls between the upper limit value and the lower limit value.

[0104] 2. Pushing force control of the lower surface brush in the second embodiment FIG. 18 is a flowchart showing an example of the flow of the pushing force control process in the second embodiment. Referring to FIG. 18, the control device 9 controls the lower surface brush operation driving unit 55a to start increasing the pushing force (step S21), and proceeds to step S22. The pushing force applied to the lower surface brush 51 is gradually increased. For this reason, the lower surface brush 51 starts to rise and, at a certain point, comes into contact with the lowermost end of the substrate W. At this stage, the cleaning of the central region R2 of the substrate W is started.

[0105] Furthermore, when the pushing force increases, the lower surface brush 51 rises together with the substrate W. As the substrate W rises, the area of the contact surface where the substrate W contacts the lower surface brush 51 gradually increases, and the substrate W comes into contact with the lower surface brush 51 in the entire region R1 of the substrate W. Furthermore, as the lower surface brush 51 rises together with the substrate W, the area of the contact surface where the substrate W contacts the lower surface brush 51 gradually decreases, and the substrate W comes into contact with the lower surface brush 51 in the annular region R3. Furthermore, when the lower surface brush 51 rises together with the substrate W, the shape of the substrate W changes, and the displacement amount of the central portion of the substrate W reaches the upper limit value.

[0106] In step S22, the period during which the lower surface brush 51 cleans the substrate W is set by It is determined whether or not a predetermined cleaning period has elapsed. If the cleaning period has not elapsed (NO in step S22), the process proceeds to step S23. If the cleaning period has elapsed (YES in step S22), the process ends.

[0107] In step S23, it is determined whether or not the displacement amount of the substrate W has reached the upper limit value. Based on the output of the displacement sensor 95, the displacement amount of the substrate W is detected. If the displacement amount of the substrate W has reached the upper limit value, the process proceeds to step S24. Otherwise, the process proceeds to step S25. When the process proceeds to step S24, the contact surface between the lower surface brush 51 and the substrate W is the annular region R3 shown in FIGS. 11 and 12.

[0108] In step S24, the control device 9 controls the lower surface brush operation driving unit 55a to start decreasing the pushing force and advances the process to step S25. As a result, the pushing force decreases over time. When the pushing force decreases, the lower surface brush 51 descends together with the substrate W. At this stage, the shape of the substrate W changes, and the area of the contact surface where the substrate W contacts the lower surface brush 51 gradually increases, and the substrate W comes into contact with the lower surface brush 51 in the entire region R1 of the substrate W. Furthermore, when the lower surface brush 51 descends together with the substrate W, the shape of the substrate W changes, and the area of the contact surface where the substrate W contacts the lower surface brush 51 gradually decreases, and the substrate W comes into contact with the lower surface brush 51 in the central region R2.

[0109] In step S25, it is determined whether the displacement amount of the substrate W is the lower limit value. Based on the output of the displacement sensor 95, the displacement amount of the substrate W is detected. If the displacement amount of the substrate W is the lower limit value, the process returns to step S21; otherwise, the process returns to step S22.

[0110] 3. Effects The substrate cleaning apparatus 1 in the second embodiment exhibits the same effects as the substrate cleaning apparatus 1 in the first embodiment. Further, since the pushing force is changed so that the displacement of the substrate W detected by the displacement sensor 95 falls within a predetermined range, the substrate W can be prevented from being damaged.

[0111] [Other Embodiments] (1) The substrate cleaning apparatus 1 in the first and second embodiments changes the force acting between the substrate W and the lower surface brush 51 by changing the pushing force applied to the lower surface brush 51. Therefore, since the force acting between the substrate W and the lower surface brush 51 is changed, the substrate W is deformed. The present invention is not limited to this. The pushing force applied to the lower surface brush 51 may be kept constant, and the pressing force applied to the substrate W by the pair of upper holding devices 10A and 10B may be changed to change the force acting between the substrate W and the lower surface brush 51. Also in this way, by changing the force acting between the substrate W and the lower surface brush 51, the deformation of the substrate W can be deformed.

[0112] (2) In the first and second embodiments, an example is shown in which the pushing force applied to the lower surface brush 51 is controlled so that the central portion of the substrate W is displaced between the upper limit value and the lower limit value. However, the pushing force applied to the lower surface brush 51 may be controlled so that the central portion of the substrate W is displaced between the lower limit value and the reference position.

[0113] [Correspondence between Each Component of the Claims and Each Part of the Embodiment] Examples of the correspondence between each component of the claims and each element of the embodiments will be described below, but the present invention is not limited to the following examples. As each component of the claims, various other elements having the configurations or functions described in the claims can also be used.

[0114] In the above embodiment, the substrate cleaning device 1 is an example of a substrate cleaning device, the pair of upper holding devices 10A and 10B are examples of substrate holding portions, the lower surface brush 51 is an example of a cleaning tool, the control device 9 is an example of a cleaning control unit, and the displacement sensor 95 is an example of a displacement sensor. [Reference Configuration] (1) According to a certain aspect of this reference configuration, the substrate cleaning apparatus includes a substrate holding portion that holds the outer peripheral end portion of the substrate, a cleaning tool that contacts the lower surface of the substrate and cleans the lower surface of the substrate, and a cleaning control portion that changes the pushing force that pushes the cleaning tool upward while the cleaning tool cleans the central region of the lower surface of the substrate. Since the pushing force that pushes the cleaning tool upward changes while the cleaning tool cleans the central region of the lower surface of the substrate, the contact surface between the cleaning tool and the substrate fluctuates due to the displacement of the substrate. Therefore, a substrate cleaning apparatus that improves the cleaning efficiency of the central region of the lower surface of the substrate can be provided. (2) The cleaning control portion continuously changes the pushing force. (3) The cleaning control portion causes the cleaning tool to change the pushing force stepwise. (4) The substrate cleaning apparatus further includes a displacement sensor that detects the displacement of the substrate, and the cleaning control portion changes the pushing force so that the displacement of the substrate falls within a predetermined range. Therefore, the substrate can be prevented from being damaged. (5) According to another aspect of this reference configuration, the substrate cleaning apparatus includes a substrate holding portion that holds the outer peripheral end portion of the substrate, a cleaning tool that contacts the lower surface of the substrate and cleans the lower surface of the substrate, and a control portion that changes the force acting between the cleaning tool and the substrate while the cleaning tool cleans the central region of the lower surface of the substrate. Therefore, since the force acting between the cleaning tool and the substrate changes while the cleaning tool cleans the central region of the lower surface of the substrate, the contact surface between the substrate and the cleaning tool can be changed while cleaning the central region of the lower surface. Therefore, a substrate cleaning apparatus that improves the cleaning efficiency of the central region of the lower surface of the substrate can be provided. (6) The substrate cleaning apparatus further includes a displacement sensor that detects the displacement of the substrate, and the control portion changes the force acting between the cleaning tool and the substrate so that the displacement of the substrate falls within a predetermined range. Therefore, the substrate can be prevented from being damaged. (7) According to still another aspect of this reference embodiment, the substrate cleaning method is a substrate cleaning method executed by a substrate cleaning apparatus including a substrate holding unit that holds an outer peripheral end portion of a substrate and a cleaning tool that contacts a lower surface of the substrate to clean the lower surface of the substrate, and includes a cleaning control step of changing a pushing-up force that pushes up the cleaning tool upward while the cleaning tool cleans a central region of the lower surface of the substrate. (8) According to still another aspect of this reference embodiment, the substrate cleaning method is a substrate cleaning method executed by a substrate cleaning apparatus including a substrate holding unit that holds an outer peripheral end portion of a substrate and a cleaning tool that contacts a lower surface of the substrate to clean the lower surface of the substrate, and includes a control step of changing a force acting between the cleaning tool and the substrate while the cleaning tool cleans a central region of the lower surface of the substrate.

Description of Reference Numerals

[0115] 1... Substrate cleaning device, 2... Unit housing, 9... Control device, 9A... Chuck control unit, 9E... Lower surface cleaning control unit, 9G... Upper surface cleaning control unit, 10A, 10B... Upper holding devices, 12A, 12B... Upper chucks, 300... Holding piece, 301... Contact surface, 302... Protrusion, 14A, 14B... Upper chuck drive units, 50... Lower surface cleaning device, 51... Lower surface brush, 55a... Lower surface brush operation drive unit, 55b... Lower surface brush lifting drive unit, 55c... Lower surface brush movement drive unit, 95... Displacement sensor, W... Substrate, BC... Lower surface central region, R1... Entire region, R2... Central region, R3... Annular region.

Claims

1. a substrate holding part for holding the outer peripheral end of the substrate; a cleaning tool that contacts the lower surface of the substrate and cleans the lower surface of the substrate; a substrate cleaning apparatus comprising a cleaning control unit that changes an upward pushing force for pushing up the cleaning tool so that an area of contact with the substrate on the upper surface of the cleaning tool changes while the cleaning tool cleans a central region of the lower surface of the substrate.

2. The substrate cleaning apparatus according to claim 1, wherein the cleaning control unit continuously changes the upward pushing force.

3. The substrate cleaning apparatus according to claim 1, wherein the cleaning control unit changes the upward pushing force in a stepwise manner when the cleaning tool cleans the central region of the lower surface of the substrate.

4. further comprising a displacement sensor for detecting displacement of the substrate, The substrate cleaning apparatus according to any one of claims 1 to 3, wherein the cleaning control unit changes the upward pushing force so that the displacement of the substrate falls within a predetermined range.

5. a substrate holding part for holding the outer peripheral end of the substrate; a cleaning tool that contacts the lower surface of the substrate and cleans the lower surface of the substrate; a substrate cleaning apparatus comprising a control unit that changes a force acting between the cleaning tool and the substrate so that an area of contact with the substrate on the upper surface of the cleaning tool changes while the cleaning tool cleans a central region of the lower surface of the substrate.

6. further comprising a displacement sensor for detecting displacement of the substrate, The substrate cleaning apparatus according to claim 5, wherein the control unit changes the force acting between the cleaning tool and the substrate so that the displacement of the substrate falls within a predetermined range.

7. a substrate holding part for holding the outer peripheral end of the substrate; a substrate cleaning method executed by a substrate cleaning apparatus comprising a cleaning tool that contacts the lower surface of the substrate and cleans the lower surface of the substrate, the method comprising: a cleaning control step of changing an upward pushing force for pushing up the cleaning tool so that an area of contact with the substrate on the upper surface of the cleaning tool changes while the cleaning tool cleans a central region of the lower surface of the substrate.

8. a substrate holding part for holding the outer peripheral end of the substrate; a substrate cleaning method executed by a substrate cleaning apparatus comprising a cleaning tool that contacts the lower surface of the substrate and cleans the lower surface of the substrate, the method comprising: a control step of changing a force acting between the cleaning tool and the substrate so that an area of contact with the substrate on the upper surface of the cleaning tool changes while the cleaning tool cleans a central region of the lower surface of the substrate.

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