Circuit board cleaning apparatus and circuit board cleaning method

Abstract

To provide a substrate cleaning device and a substrate cleaning method with which it is possible to improve cleanliness of an underside center region of substrates after cleaning.SOLUTION: A substrate cleaning device 1 comprises upper holding devices 10A, 10B that hold an outer periphery of a substrate W and an underside brush 51 that comes into contact with an underside of the substrate W and cleans the underside of the substrate W. At start of cleaning an underside center region of the substrate W, the underside brush 51 moves so as to contact a first partial region of the underside of the substrate W from a state of being separated from the underside of the substrate W. Thereafter, the underside brush 51 moves so as to contact an underside center region R1 on the underside of the substrate W. At end of cleaning the underside center region of the substrate W, the underside brush 51 moves so as to separate from a second partial region of the underside of the substrate W from a state of being in contact with the underside of the substrate W. At least one of the first partial region and the second partial region does not overlap the underside center region of the substrate W.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a substrate cleaning apparatus and a substrate cleaning method for cleaning the lower surface of a substrate.

Background Art

[0002] In order to perform various processes on various substrates such as FPD (Flat Panel Display) substrates used for liquid crystal display devices or organic EL (Electro Luminescence) display devices, semiconductor substrates, optical disk substrates, magnetic disk substrates, magneto-optical disk substrates, photomask substrates, ceramic substrates, or solar cell substrates, substrate processing apparatuses are used. A substrate cleaning apparatus is used to clean the substrate.

[0003] The substrate cleaning apparatus described in Patent Document 1 includes an upper holding device, a lower holding device, and a lower surface cleaning device. The upper holding device includes a pair of lower chucks and a pair of upper chucks. A substrate disposed between the pair of lower chucks and between the pair of upper chucks is sandwiched by the pair of lower chucks and the pair of upper chucks. Thereby, the substrate to be cleaned is held in a state where the pair of lower chucks and the pair of upper chucks contact the outer peripheral end portion of the substrate. The lower surface cleaning device cleans the central region of the lower surface of the substrate held by the upper holding device.

[0004] The lower holding device is a so-called spin chuck, which rotates the substrate in a horizontal posture while adsorbing and holding the central region of the lower surface of the substrate. The lower surface cleaning device further cleans a region surrounding the central region of the lower surface (hereinafter referred to as the lower surface outer region) of the lower surface of the substrate held by the lower holding device.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] In the substrate cleaning apparatus described in Patent Document 1, for example, the outer region of the lower surface of the substrate is cleaned after the central region of the lower surface of the substrate is cleaned. In this case, if contaminants remain in the central region of the lower surface of the substrate after cleaning, the contaminants remaining in the central region of the lower surface will be transferred to the lower holding device when the outer region of the lower surface of the substrate is cleaned.

[0007] Furthermore, in the above-described substrate cleaning apparatus, even if the central region of the substrate's lower surface is cleaned after the outer region of the substrate's lower surface is cleaned, the cleaned substrate may still have the central region of the lower surface adsorbed and held in a subsequent process. In this case as well, if the cleanliness of the central region of the lower surface is low, contaminants remaining in the central region of the lower surface will be transferred to a device (such as a spin chuck) that adsorbs and holds the central region of the lower surface.

[0008] The object of the present invention is to provide a substrate cleaning apparatus and a substrate cleaning method that can improve the cleanliness of the central region of the lower surface of the substrate after cleaning. [Means for solving the problem]

[0009] A substrate cleaning apparatus according to one aspect of the present invention is Without rotating the substrate, the above A first substrate holding portion that holds the outer edge of the substrate, A second substrate holding unit that holds the central region of the lower surface of the substrate by suction and rotates the substrate around a vertical axis, A cleaning tool that contacts the lower surface of the substrate and cleans the lower surface of the substrate, and the substrate held by the first substrate holding part The aforementioned Move the substrate and the cleaning tool relative to each other. The system is configured to allow the substrate, which is held and rotated by the second substrate holding portion, and the cleaning tool to move relative to each other. Relative moving parts and , control unit and Equipped with, The control unit, The relative moving part Control, The aforementioned substrate The aforementioned When cleaning of the central region of the lower surface begins, the cleaning tool, which is separated from the lower surface of the substrate, Outside the central region of the lower surface The cleaning tool is in contact with the lower surface of the substrate so as to contact the first partial region, and is in contact with the lower surface of the substrate when the cleaning of the central region of the lower surface of the substrate is completed. Outside the central region of the lower surfaceThe substrate is held by the first substrate holder such that it is spaced apart from the second partial region, and that the cleaning tool contacts the central region of the lower surface of the substrate for at least a portion of the cleaning tool contact period from the time the cleaning tool contacts the lower surface of the substrate until it is separated from it. The aforementioned Move at least one of the substrate and the cleaning tool. Furthermore, after cleaning the central lower surface region of the substrate with the cleaning tool, at least one of the substrate, which is held and rotated by the second substrate holding portion, and the cleaning tool is moved so that the cleaning tool contacts the outer lower surface region of the substrate that surrounds the central lower surface region of the substrate and includes at least a part of the first partial region and at least a part of the second partial region. .

[0010] A substrate cleaning method according to another aspect of the present invention includes the steps of: holding the outer peripheral edge of the substrate with a first substrate holding part without rotating the substrate; bringing a cleaning tool into contact with the lower surface of the substrate and cleaning the lower surface of the substrate; moving the substrate held by the first substrate holding part and the cleaning tool relative to each other; rotating the substrate around a vertical axis while adsorbing and holding the central region of the lower surface of the substrate with a second substrate holding part; and moving the substrate held by the second substrate holding part and the cleaning tool relative to each other, wherein the step of moving the substrate held by the first substrate holding part and the cleaning tool relative to each other is such that the cleaning tool, which is separated from the lower surface of the substrate at the start of cleaning the central region of the lower surface of the substrate, is moved to the lower surface of the substrate Bottom center area The cleaning tool, which is in contact with the outer first partial region and is in contact with the lower surface of the substrate when the cleaning of the lower central region of the substrate is completed, is used to clean the substrate. Bottom center areaThe step of moving at least one of the substrate held by the first substrate holder and the cleaning tool so as to move away from the outer second partial region and so as to move away from the lower surface of the substrate for at least a portion of the cleaning tool contact period from when the cleaning tool contacts the lower surface of the substrate until it moves away, the step of moving the substrate held by the second substrate holder and the cleaning tool relative to each other, the step of moving at least one of the substrate held and rotating by the second substrate holder and the cleaning tool so as to move the cleaning tool so that after the cleaning tool cleans the lower surface central region of the substrate, the cleaning tool contacts the lower surface outer region of the substrate that surrounds the lower surface central region of the substrate and includes at least a portion of the first partial region and at least a portion of the second partial region. [Effects of the Invention]

[0011] According to the present invention, it is possible to improve the cleanliness of the central region of the lower surface of the substrate after cleaning. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic plan view of a substrate cleaning apparatus according to the first embodiment. [Figure 2] Figure 1 is a perspective view showing the internal configuration of the substrate cleaning apparatus. [Figure 3] Figure 1 is a flowchart showing the substrate cleaning process performed by the control unit. [Figure 4] This is a bottom view of a substrate for illustrating the central region of the bottom surface defined in the substrate according to this embodiment. [Figure 5] This is a bottom view of the substrate for illustrating the lower outer region defined in the substrate according to this embodiment. [Figure 6] This is a bottom view of the substrate for illustrating the contact region and separation region defined in the substrate according to this embodiment. [Figure 7] This is a bottom view of the substrate for illustrating the gap region defined in the substrate according to this embodiment. [Figure 8] This is a diagram for explaining the details of the operations of each part of the substrate cleaning apparatus during the cleaning of the lower surface of the substrate. [Figure 9] This is a diagram for explaining the details of the operations of each part of the substrate cleaning apparatus during the cleaning of the lower surface of the substrate. [Figure 10] This is a diagram for explaining the details of the operations of each part of the substrate cleaning apparatus during the cleaning of the lower surface of the substrate. [Figure 11] This is a time chart showing the change in the rotational speed of the lower surface brush of FIG. 1 during the cleaning of the lower surface of the substrate shown in FIGS. 8 to 10. [Figure 12] This is a time chart showing the change in the rotational speed of the substrate during the cleaning of the lower surface of the substrate shown in FIGS. 8 to 10. [Figure 13] This is a contamination distribution diagram of the lower surface of the substrate after cleaning according to the embodiment. [Figure 14] This is a contamination distribution diagram of the lower surface of the substrate after cleaning according to the comparative example. [Figure 15] This is a time chart for explaining the rotational control of the lower surface brush according to another embodiment.

Embodiment for Carrying Out the Invention

[0013] Hereinafter, the substrate cleaning apparatus and the substrate cleaning method according to the embodiment of the present invention will be described with reference to the drawings. In the following description, the substrate refers to a semiconductor substrate (wafer), a substrate for an FPD (Flat Panel Display) such as a liquid crystal display device or an organic EL (Electro Luminescence) 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. Also, in the following description, the upper surface of the substrate is the circuit formation surface (front surface), and the lower surface of the substrate is the surface on the opposite side of the circuit formation surface (back surface). Further, the substrate has a circular shape except for the notch.

[0014] 1. Configuration of the Substrate Cleaning Apparatus Figure 1 is a schematic plan view of a substrate cleaning apparatus according to the first embodiment. Figure 2 is a perspective view showing the internal configuration of the substrate cleaning apparatus 1 of Figure 1. In the substrate cleaning apparatus 1 according to this embodiment, mutually orthogonal X, Y, and Z directions are defined to clarify the positional relationships. In Figure 1 and subsequent figures, the X, Y, and Z directions are indicated by arrows as appropriate. The X and Y directions are mutually orthogonal in the horizontal plane, and the Z direction corresponds to the up and down direction (vertical direction).

[0015] As shown in Figures 1 and 2, the substrate cleaning apparatus 1 has a configuration in which upper holding devices 10A, 10B, lower holding device 20, base device 30, transfer device 40, bottom surface cleaning device 50, cup device 60, top surface cleaning device 70, end surface cleaning device 80, and opening / closing device 90 are housed within a unit housing 2. In Figure 2, the unit housing 2 is shown by a dotted line.

[0016] The unit housing 2 has a rectangular parallelepiped shape and includes a rectangular base and four side walls extending upward from the four sides of the base. Two of the four side walls face each other in the Y direction. The other two side walls face each other in the X direction. An loading / unloading port 2x for the substrate W is formed in the center of one of the four side walls. An opening / closing device 90 is provided near the loading / unloading port 2x. The opening / closing device 90 includes a shutter 91 and is configured to open and close the loading / unloading port 2x using the shutter 91.

[0017] A base device 30 is provided on the bottom surface of the unit housing 2. The base device 30 includes a linear guide 31 and a movable base 32. The linear guide 31 includes two rails aligned in the X direction and extends in the Y direction so as to cross the central portion of the bottom surface in the X direction. The base device 30 is configured to allow the movable base 32 to be moved to multiple positions in the Y direction on the two rails of the linear guide 31.

[0018] The lower holding device 20 and the lower surface cleaning device 50 are arranged on the movable base 32 so as to be aligned in the Y direction. The lower holding device 20 is fixed to the upper surface of the movable base 32 and includes a suction holding part 21. The suction holding part 21 is a so-called spin chuck and has a circular suction surface capable of adsorbing and holding the lower surface of the substrate W. The suction holding part 21 is also configured to be rotatable around an axis extending in the vertical direction (the axis in the Z direction). The lower holding device 20 adsorbs and holds the lower surface of the substrate W with the suction holding part 21 and rotates the adsorbed substrate W around the axis extending in the vertical direction.

[0019] In the following explanation, when the substrate W is held by the adsorption holding part 21, the area of ​​the substrate W's lower surface that is held by the adsorption surface of the adsorption holding part 21 is referred to as the lower central region. The area of ​​the substrate W's lower surface that surrounds the lower central region is referred to as the lower outer region.

[0020] A transfer device 40 is provided on the movable base 32 near the lower holding device 20. The transfer device 40 has a plurality of support pins 41 (three in this example) that surround the suction holding part 21 in a plan view and extend in the vertical direction. The plurality of support pins 41 are provided so as to be able to move up and down between a plurality of predetermined height positions.

[0021] As described later, the upper holding devices 10A and 10B are configured to hold the substrate W at a position above the lower holding device 20. The transfer device 40 can receive the substrate W held by the lower holding device 20 and transfer it to the upper holding devices 10A and 10B by raising and lowering a plurality of support pins 41. The transfer device 40 can also receive the substrate W held by the upper holding devices 10A and 10B and transfer it to the lower holding device 20.

[0022] The bottom cleaning device 50 includes a bottom brush 51, two liquid nozzles 52, a gas ejection unit 53, a lifting and rotating support unit 54, and various drive units (not shown). The lifting and rotating support unit 54 is fixed to the upper surface of the movable base 32 so as to be adjacent to the lower holding device 20 in the Y direction. As shown in Figure 1, the bottom brush 51 has a circular cleaning surface that can contact the bottom surface of the substrate W. The bottom brush 51 is attached to the lifting and rotating support unit 54 so that the cleaning surface faces upward and the cleaning surface can rotate around an axis that extends vertically through the center of the cleaning surface. The area of ​​the cleaning surface of the bottom brush 51 is larger than the area of ​​the suction surface of the suction holding unit 21. The bottom brush 51 is made of, for example, a PVA (polyvinyl alcohol) sponge or a PVA sponge with abrasive particles dispersed in it.

[0023] The lifting and rotating support unit 54 includes a lifting mechanism for raising and lowering the lower brush 51 and a brush drive mechanism for rotating the lower brush 51. The lifting and rotating support unit 54 moves up and down while the substrate W is held by the lower holding device 20 or the upper holding devices 10A, 10B, using its lifting and lowering mechanism. As a result, the lifting and rotating support unit 54 moves the lower brush 51 between a height position that contacts the lower surface of the substrate W (a second height position and a third height position described later) and a height position that is a certain distance below the substrate W (a first height position described later).

[0024] Furthermore, the lifting and rotating support unit 54 rotates the lower brush 51 using its brush drive mechanism. As a result, the lower brush 51 rotates while at a height position where it contacts the lower surface of the substrate W, and the contact area between the lower brush 51 and the lower surface of the substrate W is cleaned.

[0025] Each of the two liquid nozzles 52 is mounted on the lifting and rotating support unit 54 so as to be located near the lower brush 51 and so as to face the cleaning surface of the lower brush 51. A cleaning fluid supply system (not shown) is connected to the liquid nozzles 52. When the lower brush 51 is in the standby position, cleaning fluid is supplied to the lower brush 51 from each liquid nozzle 52, causing the lower brush 51 to rotate. In this case, the cleaning fluid supplied to the lower brush 51 flows smoothly over the surface or inside of the lower brush 51 due to the centrifugal force generated by the rotation of the lower brush 51. As a result, contaminants adhering to the lower brush 51 in the standby position are smoothly washed away by the cleaning fluid. In addition, the drying of the lower brush 51 is suppressed as the cleaning fluid soaks into the lower brush 51.

[0026] The gas ejection unit 53 is a slit-shaped gas injection nozzle having a gas outlet extending in one direction. The gas ejection unit 53 is mounted on the lifting and rotating support unit 54 so that, in a plan view, it is located between the lower brush 51 and the adsorption holding unit 21 and the gas injection port faces upward. A gas supply system (not shown) is connected to the gas ejection unit 53. In this embodiment, nitrogen gas is used as the gas supplied to the gas ejection unit 53. The gas ejection unit 53 injects the gas supplied from the gas supply system onto the lower surface of the substrate W when the substrate W is being cleaned by the lower brush 51 and when the lower surface of the substrate W is being dried (described later). As a result, a band-shaped gas curtain extending in the X direction is formed between the lower brush 51 and the adsorption holding unit 21.

[0027] The cup device 60 is located approximately in the center of the unit housing 2 and includes a cup 61. The cup 61 is positioned to surround the lower holding device 20 and the base device 30 in a plan view and is vertically movable. In Figure 2, the cup 61 is shown by a dotted line. The cup 61 moves between predetermined lower and upper cup positions depending on which part of the lower surface of the substrate W the lower brush 51 is cleaning. The lower cup position is a height position where the upper end of the cup 61 is below the substrate W that is held by the suction holding part 21. The upper cup position is a height position where the upper end of the cup 61 is above the suction holding part 21.

[0028] The upper holding devices 10A and 10B are positioned at a height above the cup 61. In a plan view, the upper holding devices 10A and 10B face each other with the base device 30 in between. The upper holding device 10A includes a lower chuck 11A and an upper chuck 12A. The upper holding device 10B includes a lower chuck 11B and an upper chuck 12B.

[0029] The lower chucks 11A and 11B are arranged symmetrically with respect to a vertical plane extending in the Y direction through the center of the suction holding portion 21 in a plan view, and are provided to be movable in the X direction within a common horizontal plane. Each of the lower chucks 11A and 11B has two support pieces capable of supporting the lower outer region of the substrate W from below the substrate W. The upper chucks 12A and 12B are arranged symmetrically with respect to a vertical plane extending in the Y direction through the center of the suction holding portion 21 in a plan view, and are provided to be movable in the X direction within a common horizontal plane, similar to the lower chucks 11A and 11B. Each of the upper chucks 12A and 12B has two holding pieces configured to contact two portions of the outer peripheral edge of the substrate W and to hold the outer peripheral edge of the substrate W.

[0030] In the upper holding devices 10A and 10B, the distance between the lower chuck 11A and upper chuck 12A and the lower chuck 11B and upper chuck 12B is adjusted. As a result, the upper holding devices 10A and 10B can hold the substrate W above the lower holding device 20 by sandwiching the substrate W between the lower chuck 11A and upper chuck 12A and the lower chuck 11B and upper chuck 12B. In addition, the upper holding devices 10A and 10B can release the held substrate W by moving the lower chuck 11A and upper chuck 12A and the lower chuck 11B and upper chuck 12B further apart from each other.

[0031] As shown in Figure 1, an upper surface cleaning device 70 is provided on one side of the cup 61 in the X direction. As shown in Figure 2, the upper surface cleaning device 70 includes a rotating support shaft 71, an arm 72, and a spray nozzle 73. The rotating support shaft 71 is provided to extend vertically, be vertically movable, and rotatable. The arm 72 is provided to extend horizontally from the upper end of the rotating support shaft 71 at a position above the upper holding devices 10A and 10B. A spray nozzle 73 is attached to the tip of the arm 72. A fluid supply system (not shown) is connected to the spray nozzle 73. Cleaning liquid and gas are supplied to the spray nozzle 73 from the fluid supply system (not shown). As a result, the cleaning liquid and gas are mixed in the spray nozzle 73 to produce a mixed fluid. The produced mixed fluid is sprayed downward from the spray nozzle 73.

[0032] In the top surface cleaning device 70, for example, with the substrate W held and rotated by the lower holding device 20, the height position of the rotation support shaft 71 is adjusted so that the spray nozzle 73 moves above the substrate W, and the rotation support shaft 71 rotates. In this state, the mixed fluid is sprayed from the spray nozzle 73 onto the substrate W. As a result, the entire top surface of the substrate W is cleaned.

[0033] As shown in Figure 1, an end cleaning device 80 is provided on the other side of the cup 61 in the X direction. As shown in Figure 2, the end cleaning device 80 includes a rotating support shaft 81, an arm 82, and a bevel brush 83. The rotating support shaft 81 is provided to extend vertically, be vertically movable, and rotatable. The arm 82 is provided to extend horizontally from the upper end of the rotating support shaft 81 at a position above the upper holding devices 10A and 10B. A bevel brush 83 is provided at the tip of the arm 82 so as to protrude downward and be rotatable around a vertical axis.

[0034] In the edge cleaning device 80, for example, with the substrate W held and rotated by the lower holding device 20, the height position of the rotation support shaft 81 is adjusted so that the bevel brush 83 contacts the outer edge of the substrate W, and the rotation support shaft 81 rotates. Furthermore, the bevel brush 83 provided at the tip of the arm 82 rotates around the vertical axis. As a result, the entire outer edge of the substrate W is cleaned.

[0035] As shown in Figure 1, the substrate cleaning apparatus 1 further includes a control unit 9. The control unit 9 includes, for example, a CPU (Central Processing Unit) and memory or a microcomputer. The memory stores a substrate cleaning program. The CPU of the control unit 9 controls the operation of each of the above components (10A, 10B, 20, 30, 40, 50, 60, 70, 80, 90) by executing the substrate cleaning program stored in memory.

[0036] 2. Basic flow of circuit board cleaning process The following describes the substrate cleaning process performed by the control unit 9 in Figure 1 in the substrate cleaning apparatus 1 described above. Figure 3 is a flowchart showing the substrate cleaning process performed by the control unit 9 in Figure 1.

[0037] The substrate cleaning and drying process according to this embodiment is performed by the CPU of the control unit 9 executing a substrate cleaning program stored in the memory device. In the initial state, the base device 30 is assumed to have the movable base 32 positioned such that the suction holding part 21 of the lower holding device 20 is located in the center of the cup 61 in a plan view.

[0038] First, the control unit 9 controls the opening / closing device 90 to open the input / output port 2x and receive the substrate W being fed in from outside the substrate cleaning device 1 into the unit housing 2 (step S1).

[0039] Next, the control unit 9 controls the transfer device 40 to receive the substrate W with the multiple support pins 41 and transfer the received substrate W to the upper holding devices 10A and 10B (step S2). At this time, the control unit 9 controls the upper holding devices 10A and 10B to hold the outer edge of the substrate W above the lower holding device 20 (step S3). If the substrate W brought in from outside the substrate cleaning device 1 can be placed on the lower chucks 11A and 11B, the process in step S2 may be omitted. The input / output port 2x, which was opened in step S1, is closed by the shutter 91 after the substrate W has been received by the transfer device 40.

[0040] Subsequently, the control unit 9 controls the base device 30 and the bottom surface cleaning device 50 to clean the central area of ​​the bottom surface of the substrate W (step S4). Details of the operation of each part of the substrate cleaning device 1 during the cleaning of the central area of ​​the bottom surface of the substrate W will be described later.

[0041] During cleaning in step S4, the central region of the underside of the substrate W is cleaned by the underside brush 51 soaked in cleaning solution. As a result, the cleaning solution adheres to the central region of the underside of the substrate W. The control unit 9 then dries the central region of the underside of the substrate W by further controlling the base device 30 and the underside cleaning device 50 (step S5). Specifically, the control unit 9 controls the base device 30 while gas is being ejected from the gas ejection unit 53 toward the underside of the substrate W (a state in which a gas curtain is generated), so that the gas ejection unit 53 moves relative to the underside of the substrate W so that it passes through the central region of the underside in a plan view. As a result, the cleaning solution adhering to the central region of the underside of the substrate W is pushed away by the gas curtain to a position away from the central region of the underside of the substrate W, and the central region of the underside dries.

[0042] Next, the control unit 9 controls the transfer device 40 to receive the substrate W held by the upper holding devices 10A and 10B using the multiple support pins 41, and transfers the received substrate W to the lower holding device 20 (step S6).

[0043] Next, the control unit 9 controls the lower holding device 20 to hold the central region of the lower surface of the substrate W with the suction holding unit 21 (step S7). During steps S6 and S7, the base device 30 is positioned so that the center of the substrate W is located at the center of the suction holding unit 21 in a plan view. ru As a result, the substrate W is held by the suction holding unit 21 with its center positioned on the rotation center (rotation axis) of the suction holding unit 21.

[0044] Furthermore, the control unit 9 controls the lower holding device 20, the base device 30, the bottom surface cleaning device 50, the top surface cleaning device 70, the edge cleaning device 80, and the drying device 100 to clean the entire top surface, the outer peripheral edge, and the outer region of the bottom surface of the substrate W (step S8). Details of the operation of each part of the substrate cleaning device 1 when cleaning the outer region of the bottom surface of the substrate W will be described later.

[0045] After cleaning the entire upper surface, outer edges, and outer lower surface area of ​​the substrate W is complete, the control unit 9 controls the lower holding device 20 to rotate the substrate W at high speed and dry the entire substrate W (step S9). This drying method, in which the entire substrate W is dried by rotating it at high speed, is called spin drying.

[0046] Finally, the control unit 9 opens the input / output port 2x by controlling the opening / closing device 90. As a result, the substrate W is transported outside the substrate cleaning device 1 (step S10), and the substrate cleaning process is completed. After the substrate W is discharged, the input / output port 2x, which was opened in step S10, is closed by the shutter 91.

[0047] Furthermore, during steps S8 and S9 of the above-described series of processes, the control unit 9 controls the cup device 60 to hold the cup 61 in the upper cup position. As a result, when cleaning the entire upper surface, outer peripheral edges, and outer lower surface region of the substrate W, and when spin-drying the substrate W, droplets scattered from the substrate W are caught by the cup 61 and discharged to the outside of the substrate cleaning device 1. In addition, during the processes other than steps S8 and S9 of the above-described series of processes (steps S1 to S7, S10), the control unit 9 controls the cup device 60 to hold the cup 61 in the lower cup position.

[0048] 3. Multiple regions defined on the lower surface of the substrate W To explain in detail the operation of each part of the substrate cleaning apparatus 1 during cleaning of the central and outer lower surface regions of the substrate W, we will first describe the multiple regions defined on the lower surface of the substrate W. These multiple regions include, in addition to the central and outer lower surface regions described above, a contact region, a separated region, and a gap region.

[0049] Figure 4 is a bottom view of the substrate W for illustrating the central bottom region defined in this embodiment. The central bottom region R1 is the area on the bottom surface of the substrate W where the suction surface of the suction holding part 21 adheres, as described above. Therefore, as shown by the hatching in Figure 4, the central bottom region R1 has the same circular shape as the suction surface of the suction holding part 21. The center of the central bottom region R1 coincides with, or approximately coincides with, the center WC of the substrate W. Also, the area of ​​the central bottom region R1 is smaller than the area of ​​the cleaning surface of the bottom brush 51. In Figure 4, the outer circumference of the bottom brush 51 when its center is aligned with the center WC of the substrate W is shown by a dashed line, along with the central bottom region R1. The substrate W in this embodiment has, for example, a diameter of 300 mm. The bottom brush 51 has a diameter of approximately 108 mm. The diameter of the suction holding part 21 is smaller than 108 mm.

[0050] Figure 5 is a bottom view of the substrate W for illustrating the lower outer region defined in the substrate W according to this embodiment. As shown by hatching in Figure 5, the lower outer region R2 has an annular shape that includes the outer peripheral edge of the substrate W and surrounds the lower central region R1. In Figure 5, the outline of the lower central region R1 in Figure 4 is shown by a dotted line along with the lower outer region R2. Furthermore, the outer circumference of the cleaning surface of the lower brush 51 when its center is aligned with the center WC of the substrate W is shown by a dashed line. In this example, the inner diameter of the lower outer region R2 is smaller than the outer diameter of the cleaning surface of the lower brush 51. However, the inner diameter of the lower outer region R2 and the outer diameter of the cleaning surface of the lower brush 51 may be the same.

[0051] Figure 6 is a bottom view of the substrate W for illustrating the contact region and separation region defined in the substrate W according to this embodiment. In this embodiment, the contact region refers to the position on the bottom surface of the substrate W when the bottom brush 51, which is separated from the substrate W, is brought into contact with the bottom surface of the substrate W when cleaning the central region R1 on the bottom surface of the substrate W. In this embodiment, the separation region refers to the position on the bottom surface of the substrate W when the bottom brush 51, which is in contact with the substrate W, is separated from the bottom surface of the substrate W when cleaning the central region R1 on the bottom surface of the substrate W.

[0052] As shown by hatching in Figure 6, the contact region R3 and separation region R4 in this embodiment are defined in a common position on the lower surface of the substrate W and both have the same circular shape as the cleaning surface of the lower surface brush 51. Furthermore, the contact region R3 and separation region R4 are located between the outer peripheral edge of the substrate W and the lower surface central region R1. In other words, the contact region R3 and separation region R4 in this embodiment do not overlap with the lower surface central region R1 on the lower surface of the substrate W. In Figure 6, the outer circumference circle of the lower surface central region R1 in Figure 4 is shown by a dotted line, along with the contact region R3 and separation region R4. Also in Figure 6, the inner circumference circle of the lower surface outer region R2 in Figure 5 is shown by a dashed line.

[0053] Figure 7 is a bottom view of the substrate W to illustrate the gap region defined in the substrate W according to this embodiment. As shown by the dot pattern in Figure 7, the gap region R5 according to this embodiment is a region located between a part of the outer edge of the substrate W and the contact region R3 and separation region R4 in Figure 6. In Figure 7, the outer circles of the contact region R3 and separation region R4 in Figure 6 are shown as dotted lines, along with the gap region R5.

[0054] 4. Detailed operation of each part of the substrate cleaning device 1 during cleaning of the underside of substrate W. Figures 8 to 10 are diagrams illustrating the detailed operation of each part of the substrate cleaning apparatus 1 during the cleaning of the underside of the substrate W. Here, "cleaning the underside of the substrate W" refers to the period from the start of step S4 to the end of step S9 in Figure 3. Each of Figures 8 to 10 shows the operating state of parts of the substrate cleaning apparatus 1 (mainly the lower holding device 20, the base device 30, and the underside cleaning device 50) at multiple points in time during the cleaning of the underside of the substrate W, arranged chronologically from left to right. Furthermore, Figures 8 to 10 show the operating state of the substrate cleaning apparatus 1 at each point in time in schematic plan views and schematic side views. The schematic side views shown in Figures 8 to 10 correspond to the schematic side views along line AA in Figure 1. Additionally, Figures 8 to 10 show the cleaning state of the underside of the substrate W at each point in time in the underside view of the substrate W.

[0055] Figure 11 is a time chart showing the change in rotational speed of the bottom brush 51 shown in Figure 1 during the cleaning of the bottom surface of the substrate W shown in Figures 8 to 10. The time chart in Figure 11 is shown as a graph. In the graph in Figure 11, the vertical axis represents the rotational speed of the bottom brush 51, and the horizontal axis represents time. Figure 12 is a time chart showing the change in rotational speed of the substrate W during the cleaning of the bottom surface of the substrate W shown in Figures 8 to 10. The time chart in Figure 12 is shown as a graph. In the graph in Figure 12, the vertical axis represents the rotational speed of the substrate W, and the horizontal axis represents time.

[0056] Here, when the substrate cleaning device 1 cleans the bottom surface of the substrate W, the movable base 32 of the base device 30 moves in the Y direction on the linear guide 31 between a predetermined first horizontal position P1, a second horizontal position P2, and a third horizontal position P3. In the schematic side views of Figures 8 to 12, the point labeled P1 indicates the position of the center of the movable base 32 when it is in the first horizontal position P1. The point labeled P2 indicates the position of the center of the movable base 32 when it is in the second horizontal position P2. Furthermore, the point labeled P3 indicates the position of the center of the movable base 32 when it is in the third horizontal position P3.

[0057] Furthermore, when cleaning the underside of the substrate W in the substrate cleaning apparatus 1, the underside brush 51 moves in the Z direction (vertical direction) between a predetermined first height position, a second height position, and a third height position on the movable base 32. The first height position is the height position of the underside brush 51 when it is at the lowest position within the range that the lifting and lowering rotation support unit 54 can move up and down. The second height position is higher than the first height position and is the height position of the underside brush 51 when the cleaning surface of the underside brush 51 contacts the underside of the substrate W held by the upper holding devices 10A and 10B. The third height position is higher than the first height position and lower than the second height position and is the height position of the underside brush 51 when the cleaning surface of the underside brush 51 contacts the underside of the substrate W held by the lower holding device 20.

[0058] The operation of the base device 30 and the bottom cleaning device 50 during bottom cleaning of the substrate W will be explained in detail below using Figures 8 to 12. As shown in the left part of Figure 8, at time t1 when bottom cleaning of the substrate W is started, the substrate W is held in a horizontal position by the upper holding devices 10A and 10B and fixed inside the substrate cleaning device 1. In this state, the movable base 32 of the base device 30 is in the first horizontal position P1. At this time, the rotation center (rotation axis) of the suction holding part 21 is located on the vertical axis passing through the center WC of the substrate W. Also, in a plan view, most (part) of the cleaning surface of the bottom brush 51 overlaps with the substrate W, and a small portion (the remaining part) of the cleaning surface of the bottom brush 51 is located outside the outer edge of the substrate W. In the radial direction of the substrate W, the maximum amount of overhang of the cleaning surface of the bottom brush 51 relative to the bottom surface of the substrate W is, for example, 7 mm (see the symbol d1 in the upper left part of Figure 8).

[0059] Furthermore, at time t1, the bottom brush 51 is held at a first height position below the substrate W. As a result, the bottom brush 51 is separated from the substrate W by a predetermined distance. The bottom brush 51 also rotates at a predetermined first rotation speed bv1 (see Figure 11), and cleaning liquid is supplied to the bottom brush 51 from the liquid nozzle 52. The first rotation speed bv1 is set to such an extent that the cleaning liquid supplied to the bottom brush 51 does not splash around the bottom brush 51 (for example, between 60 rpm and 130 rpm), and in this embodiment, it is 60 rpm. Note that from time t1 to time t8, which will be described later, the rotation of the suction holding unit 21 is stopped (see Figure 12).

[0060] When cleaning the underside of the substrate W begins, the movable base 32 moves from a first horizontal position P1 to a second horizontal position P2 from time t1 to time t2 in order to clean the central region of the underside of the substrate W. As shown in the central part of Figure 8, when the movable base 32 is at the second horizontal position P2 at time t2, the rotation center (rotation axis) of the suction holding part 21 is offset from the vertical axis passing through the center WC of the substrate W. Also, in a plan view, the entire cleaning surface of the underside brush 51 overlaps the substrate W. At this time, a gap is formed between the outer peripheral edge of the underside brush 51 and the outer peripheral edge of the substrate W in the radial direction of the substrate W. The minimum size of the gap between the outer peripheral edge of the underside brush 51 and the outer peripheral edge of the substrate W is, for example, 3 mm (see the symbol d2 in the upper central part of Figure 8). When the movable base 32 is at the second horizontal position P2, the region on the underside of the substrate W that faces the cleaning surface of the underside brush 51 in the vertical direction becomes the contact region R3 in Figure 6.

[0061] Next, at time t2, the supply of cleaning fluid from the liquid nozzle 52 to the lower brush 51 is stopped. Also from time t2, the lower brush 51 is raised toward the lower surface of the substrate W by the lifting and rotating support unit 54. As a result, as shown in the right portion of Figure 8, at time t3, the lower brush 51 reaches a second height position, causing the lower brush 51 to contact the contact area R3 on the lower surface of the substrate W. Here, as shown in Figure 11, the rotational speed of the lower brush 51 increases from the first rotational speed bv1 to a predetermined second rotational speed bv2 as the lower brush 51 rises from time t2 to time t3. The second rotational speed bv2 is set within a predetermined speed range (for example, 100 rpm to 200 rpm) that is higher than the first rotational speed bv1, and in this embodiment it is 150 rpm.

[0062] As described above, the bottom brush 51, which is soaked in cleaning fluid, comes into contact with the underside of the substrate W, and as the bottom brush 51 rotates, the contact area (contact region R3) of the bottom brush 51 on the underside of the substrate W is cleaned. In the lower right section of Figure 8, the area cleaned by the bottom brush 51 is indicated by hatching in the underside view of the substrate W. At this time, the bottom brush 51 does not come into contact with the gap region R5 between the outer edge of the substrate W and the contact region R3 in a plan view. As a result, contaminants removed by the bottom brush 51 in the contact region R3 are prevented from going beyond the gap region R5 and around to the upper side of the substrate W from the outer edge. Therefore, a decrease in the cleanliness of the outer edge of the substrate W and the upper surface of the substrate W is suppressed.

[0063] Next, with the bottom brush 51 in contact with the underside of the substrate W, the movable base 32 moves in the Y direction from the second horizontal position P2 to the third horizontal position P3 from time t3 to time t4. At this time, the rotation speed of the bottom brush 51 is maintained at the second rotation speed bv2. As a result, as shown by the hatching in the lower left section of the underside view of the substrate W in Figure 9, a portion of the underside of the substrate W, including the central area R1, is cleaned by the bottom brush 51.

[0064] Furthermore, while the bottom brush 51 is in contact with the lower surface of the substrate W, the movable base 32 moves in the Y direction from the third horizontal position P3 to the second horizontal position P2 between time points t4 and t5. As a result, the bottom brush 51 reaches the separation region R4 on the lower surface of the substrate W, as shown in the central part of Figure 9. Here, between time points t3 and t5, gas is ejected from the gas ejection section 53 toward the lower surface of the substrate W, forming a gas curtain. This prevents the cleaning liquid contained in the bottom brush 51 from remaining in the central region R1 of the lower surface, even if it adheres to the lower surface of the substrate W.

[0065] At time t5, in plan view, the outer edge of the substrate W and Separation area R4The lower brush 51 does not come into contact with the gap region R5 between the lower brush and the substrate. This prevents contaminants removed by the lower brush 51 in the gap region R5 from spreading beyond the gap region R5 to the upper surface of the substrate W from the outer edge of the substrate W. Therefore, a decrease in the cleanliness of the outer edge of the substrate W and the upper surface of the substrate W is suppressed.

[0066] Next, from time t5 to time t6, the lower brush 51 descends so as to move away from the substrate W. As a result, the lower brush 51 moves away from the separation region R4 of the substrate W, and as shown in the right portion of Figure 9, the lower brush 51 reaches a first height position at time t6. Here, as shown in Figure 11, the rotational speed of the lower brush 51 decreases from a second rotational speed bv2 to a first rotational speed bv1 as the lower brush 51 descends from time t5 to time t6. Also at time t6, the supply of cleaning liquid from the liquid nozzle 52 to the lower brush 51 is resumed. As a result, contaminants adhering to the lower brush 51 are washed away by the supplied cleaning liquid.

[0067] Next, from time t6 to time t7, the movable base 32 moves from the second horizontal position P2 towards the first horizontal position P1. As a result, as shown in the left portion of Figure 10, the bottom brush 51 returns to the state at time t1, when the cleaning of the bottom surface of the substrate W begins (see the left portion of Figure 8).

[0068] Next, between time points t6 and t7, the substrate W is transferred from the upper holding devices 10A and 10B to the lower holding device 20 by the transfer device 40 shown in Figure 1. As a result, as shown in the central part of Figure 10, at time point t8, with the movable base 32 of the base device 30 in the first horizontal position P1, the central region R1 of the lower surface of the substrate W is held by the suction holding part 21 of the lower holding device 20.

[0069] Subsequently, the supply of cleaning fluid from the liquid nozzle 52 to the lower brush 51 is stopped, and the rotation of the substrate W by the lower holding device 20 is started, as shown in Figure 12. The rotation speed wv1 of the substrate W rotated by the lower holding device 20 is set to, for example, 200 rpm or more and 500 rpm or less, and in this embodiment it is 500 rpm. Cleaning fluid is also supplied from a back rinse nozzle (not shown) toward the lower surface of the substrate W rotating by the lower holding device 20.

[0070] Next, the lower brush 51 rises toward the lower surface of the substrate W. As a result, as shown in the right portion of Figure 10, the lower brush 51 reaches a third height position at time t9, and contacts the outer region R2 of the lower surface of the rotating substrate W.

[0071] From time t9 until time t10, after a certain period has elapsed, the rotation of the substrate W is maintained while the bottom brush 51 remains in contact with the outer lower surface region R2 of the substrate W. As a result, the outer lower surface region R2 of the substrate W is cleaned. In the lower right section of Figure 10, the area cleaned by the bottom brush 51 is indicated by hatching in the lower view of the substrate W.

[0072] During the period from time t9 to time t10, the upper surface of the rotating substrate W is further cleaned by the upper surface cleaning device 70 shown in Figure 1. In addition, the outer peripheral edges of the rotating substrate W are further cleaned by the edge cleaning device 80 shown in Figure 1. As a result, when the lower outer region R2 of the substrate W is cleaned, contaminants do not spread from the outer peripheral edges of the substrate W to the upper surface of the substrate W. A detailed explanation of the cleaning of the upper surface and outer peripheral edges of the substrate W is omitted.

[0073] Subsequently, from time t10 to time t11, the lower brush 51 is lowered away from the substrate W by the lifting and lowering rotation support unit 54. Also, the rotation speed wv1 of the substrate W is maintained for a predetermined period. This spin-dries the substrate W. Finally, as shown in Figure 12, the rotation of the substrate W is stopped at time t12, and the cleaning of the underside of the substrate W is completed.

[0074] 5. Effects of the Embodiment (a) When the bottom brush 51, which is separated from the bottom surface of the substrate W, comes into contact with a portion of the bottom surface of the substrate W, contaminants caused by the contact of the bottom brush 51 are likely to remain in that portion of the substrate. Also, when the cleaning tool, which is in contact with the substrate, comes into contact with a portion of the bottom surface of the substrate, contaminants caused by the separation of the bottom brush 51 are likely to remain in that portion of the substrate.

[0075] In the following explanation, as shown in Figures 11 and 12, the period during which the lower brush 51 is in contact with the lower surface of the substrate W is referred to as the contact period.

[0076] In the substrate cleaning apparatus 1 described above, the lower brush 51 contacts the central region R1 on the lower surface of the substrate W for at least a portion of the contact period during which the lower brush 51 contacts the lower surface of the substrate W. As a result, the central region R1 on the lower surface of the substrate W is cleaned. In addition, the contact region R3 and the separation region R4 do not overlap with the central region R1 on the lower surface of the substrate W. As a result, contaminants are less likely to remain in the central region R1 on the lower surface of the substrate W after cleaning compared to the case where the contact region R3 and the separation region R4 overlap with the central region R1. Therefore, the cleanliness of the central region R1 on the lower surface of the substrate W after cleaning is improved.

[0077] (b) In the substrate cleaning apparatus 1 described above, after cleaning the central region R1 of the lower surface of the substrate W, the outer region R2 of the lower surface of the substrate W is cleaned while the central region R1 is held by the lower holding device 20. Here, the contact region R3 and the separation region R4 largely overlap with the outer region R2 of the lower surface. As a result, even if contaminants remain in the contact region R3 and the separation region R4 after cleaning the central region R1 of the lower surface of the substrate W, these contaminants are removed when the outer region R2 of the lower surface of the substrate W is cleaned. Therefore, the overall cleanliness of the lower surface of the substrate W is improved after cleaning the central region R1 and the outer region R2 of the lower surface of the substrate W.

[0078] Furthermore, with the above configuration, when the lower outer region R2 of the substrate W is cleaned, the lower central region R1 maintains a high degree of cleanliness. Therefore, even when multiple substrates W are cleaned sequentially, the occurrence of cross-contamination between multiple substrates W via the adsorption holding portion 21 is suppressed.

[0079] (c) When the lower brush 51, which is separated from the lower surface of the substrate W, comes into contact with a portion of the lower surface of the substrate W, contaminants caused by the contact of the lower brush 51 are likely to remain in that portion of the lower surface of the substrate W. The degree of contaminant residue in this case is lower when the relative speed difference between the lower brush 51 and the substrate W is large when the lower brush 51 comes into contact with a portion of the lower surface of the substrate W.

[0080] Furthermore, when the bottom brush 51, which is in contact with a portion of the lower surface of the substrate W, separates from the lower surface of the substrate W, contaminants caused by the separation of the bottom brush 51 are likely to remain in that portion of the lower surface of the substrate W. The degree of contaminant residue in this case is lower when the relative speed difference between the bottom brush 51 and the substrate W is large when the bottom brush 51 separates from a portion of the lower surface of the substrate W.

[0081] In the substrate cleaning apparatus 1 described above, the bottom brush 51 is positioned at a second height when cleaning the central region R1 on the lower surface of the substrate W. By rotating the bottom brush 51, which is in contact with the lower surface of the substrate W, contaminants adhering to the substrate W are removed. On the other hand, when the lower surface of the substrate W is not being cleaned, the bottom brush 51 is positioned at a first height. At the first height, the bottom brush 51 rotates at a first rotational speed bv1. If the rotational speed of the bottom brush 51 is excessively high, contaminants or droplets adhering to the bottom brush 51 will scatter around the bottom brush 51, reducing the cleanliness inside the substrate cleaning apparatus 1. Therefore, the first rotational speed bv1 is set lower than at least the second rotational speed bv2 when cleaning the central region R1 on the lower surface of the substrate W.

[0082] According to the above configuration, at the point when the bottom brush 51 contacts the substrate W to clean the central region R1 of the bottom surface (time t3 in Figure 11), the bottom brush 51 rotates at a second rotation speed bv2 which is higher than the first rotation speed bv1. Also, at the point when the bottom brush 51 separates from the substrate W after cleaning the central region R1 of the bottom surface (time t5 in Figure 11), the bottom brush 51 rotates at a second rotation speed bv2 which is higher than the first rotation speed bv1. As a result, the cleanliness of the bottom surface of the substrate W after cleaning is improved compared to when the bottom brush 51 rotates at the first rotation speed bv1 or does not rotate at the point when the bottom brush 51 contacts the substrate W and when it separates from the substrate W.

[0083] Furthermore, during cleaning of the lower outer region R2 of the substrate W, the substrate W is held in place by the adsorption holding unit 21 and rotates at a relatively high rotational speed (e.g., 500 rpm). Therefore, even when the rotational speed of the lower brush 51 is maintained at the first rotational speed bv1, a relatively high rotational speed difference is generated between the lower brush 51 and the substrate W. Consequently, when the lower brush 51 contacts the substrate W and separates from the substrate W, the residue of contaminants caused by such contact and separation is suppressed on the lower surface of the substrate W.

[0084] (d) The degree of residue of contaminants due to contact with the lower brush 51 is significantly reduced when the relative speed difference between the lower brush 51 and the substrate W when the lower brush 51 is in contact with the substrate W is greater than a certain relative speed difference. Similarly, the degree of residue of contaminants due to separation of the lower brush 51 is also significantly reduced when the relative speed difference between the lower brush 51 and the substrate W when the lower brush 51 is separated from the substrate W is greater than a certain relative speed difference. Furthermore, these certain relative speed differences are lower than the second rotational speed bv2 when the central region R1 of the lower surface of the substrate W is being cleaned.

[0085] According to the substrate cleaning apparatus 1 described above, the lower brush 51 rotates at a second rotational speed bv2 at the moment it contacts the substrate W and at the moment it separates from the substrate W. As a result, the cleanliness of the lower surface of the substrate W after cleaning is improved compared to when the lower brush 51 rotates at a first rotational speed bv1 or does not rotate.

[0086] The specific relative speed difference described above may be determined by experiment or simulation depending on the combination of the substrate W and the bottom brush 51. In this case, by setting the rotational speed of the bottom brush 51 at the time of contact with and separation from the substrate W to be greater than the determined specific relative speed difference, the cleanliness of the bottom surface of the substrate W after cleaning can be improved.

[0087] (e) In the above embodiment, the bottom brush 51, which is at a first height position, rises to a second height position in order to clean the central region R1 of the lower surface of the substrate W. At this time, the rotational speed of the bottom brush 51 increases from the first rotational speed bv1 to the second rotational speed bv2 as the bottom brush 51 rises (times t2 to t3 in Figure 11).

[0088] In this case, the raising of the lower brush 51 and the adjustment of the rotation speed of the lower brush 51 are performed in parallel, so the decrease in the cleaning efficiency of the substrate W caused by adjusting the rotation speed of the lower brush 51 is suppressed.

[0089] Furthermore, the rotational speed of the lower brush 51 should be the second rotational speed bv2 when the lower brush 51 reaches the second height position. Therefore, the rotational speed of the lower brush 51 is not limited to the example in Figure 11; it may increase gradually from time t2 to time t3, or it may increase continuously while changing the acceleration.

[0090] (f) In the above embodiment, after cleaning the central region R1 on the lower surface of the substrate W, the lower brush 51, which is at the second height position, descends to the first height position. At this time, the rotational speed of the lower brush 51 decreases from the second rotational speed bv2 to the first rotational speed bv1 as the lower brush 51 descends (times t5 to t6 in Figure 11).

[0091] In this case, the descent of the lower brush 51 and the adjustment of the rotation speed of the lower brush 51 are performed in parallel, so the decrease in the cleaning efficiency of the substrate W caused by adjusting the rotation speed of the lower brush 51 is suppressed.

[0092] The rotational speed of the lower brush 51 should be the second rotational speed bv2 when the lower brush 51 begins to descend from the second height position. Therefore, the rotational speed of the lower brush 51 is not limited to the example in Figure 11; it may decrease gradually from time t5 to time t6, or it may decrease continuously while changing the acceleration.

[0093] 6. Testing for contamination caused by contact and separation of the lower brush 51. The inventors conducted the following tests in the above-described substrate cleaning apparatus 1 to confirm how much the cleanliness of the substrate W after cleaning is improved by ensuring that the contact area R3 and the separation area R4 do not overlap with the central area R1 on the lower surface of the substrate W.

[0094] First, the inventors prepared a substrate W after cleaning the bottom surface according to the examples in Figures 8 to 12 as the cleaned substrate according to the embodiment. Furthermore, the inventors prepared a cleaned substrate W after cleaning the bottom surface using the same procedure as the examples in Figures 8 to 12, except that the contact area R3 and gap area R5 are set to overlap the central area R1 of the bottom surface. This cleaned substrate was then prepared as the cleaned substrate according to the comparative example.

[0095] Specifically, when cleaning the central lower region R1 of the substrate W in the comparative example, with the movable base 32 held in a third horizontal position P3, the lower brush 51 was raised from a first height position to a second height position, thereby bringing the cleaning surface of the lower brush 51 into contact with the contact region R3 (central lower region R1) of the substrate W. Furthermore, with the movable base 32 held in a third horizontal position P3, the lower brush 51 was lowered from a second height position to a first height position, thereby separating the cleaning surface of the lower brush 51 from the separated region R4 (central lower region R1) of the substrate W.

[0096] Furthermore, the inventors confirmed the contamination status of the underside of each of the cleaned substrates according to the examples and comparative examples prepared as described above using a particle counter. Figure 13 is a contamination distribution diagram of the underside of the cleaned substrate according to the examples, and Figure 14 is a contamination distribution diagram of the underside of the cleaned substrate according to the comparative examples. In Figures 13 and 14, the distribution of contaminants adhering to the underside of the cleaned substrates according to the examples and comparative examples is shown by multiple black dots.

[0097] As shown in Figures 13 and 14, the amount of contaminants adhering to the underside of the substrate after cleaning in the embodiment is less than the amount of contaminants adhering to the underside of the substrate after cleaning in the comparative example. Furthermore, in the underside of the substrate after cleaning in the embodiment, chuck marks from the adsorption holding part 21 are observed around the outer periphery of the central region R1 of the underside and its vicinity, but the amount of contaminants adhering to other areas is relatively small.

[0098] On the other hand, in the comparative example, on the underside of the cleaned substrate, numerous contaminants are attached to the outer periphery of the central region R1 of the underside and its vicinity, along with chuck marks from the adsorption holding portion 21. In addition, the amount of contaminants attached to other regions is also relatively large.

[0099] These results revealed that by setting the contact area R3 and separation area R4 so as not to overlap with the central lower surface area R1 of the substrate W, contaminants caused by contact or separation of the lower surface brush 51 are less likely to remain in the central lower surface area R1.

[0100] 7. Other Embodiments (a) In the substrate cleaning apparatus 1 according to the above embodiment, the contact area R3 and the separation area R4 are determined so that they do not overlap with the lower central area R1, but the present invention is not limited thereto. Either the contact area R3 or the separation area R4 may overlap with the lower central area R1. Even in this case, the cleanliness of the lower central area R1 after cleaning is improved compared to the case where both the contact area R3 and the separation area R4 overlap with the lower central area R1.

[0101] (b) In the above embodiment, at the point in time (time t3 in Figure 11) when the bottom brush 51 contacts the substrate W to clean the central lower region R1, the bottom brush 51 rotates at a second rotational speed bv2. The second rotational speed bv2 in the above embodiment is the rotational speed of the bottom brush 51 when cleaning the central lower region R1 of the substrate W. However, the present invention is not limited thereto.

[0102] The second rotational speed bv2, which corresponds to the point in time (time t3 in Figure 11) when the bottom brush 51 contacts the substrate W to clean the central area R1 of the bottom surface, may be set higher than the rotational speed at which the bottom brush 51 contacts and cleans the central area R1 of the bottom surface (hereinafter referred to as the third rotational speed). Here, the third rotational speed is, for example, a speed at which the central area R1 of the bottom surface can be suitably cleaned while the bottom brush 51 is in contact with the central area R1 of the bottom surface.

[0103] Alternatively, at the point when the bottom brush 51 contacts the substrate W after cleaning the central region R1 of the bottom surface (time t3 in Figure 11), the bottom brush 51 may rotate at a rotational speed lower than the second rotational speed bv2.

[0104] Furthermore, in the substrate cleaning apparatus 1 according to the above embodiment, at the point when the lower brush 51 separates from the substrate W after cleaning the central lower region R1 (time t5 in Figure 11), the lower brush 51 rotates at a second rotational speed bv2. The second rotational speed bv2 according to the above embodiment is the rotational speed of the lower brush 51 when cleaning the central lower region R1 of the substrate W. However, the present invention is not limited thereto.

[0105] The second rotational speed bv2, which corresponds to the point in time (time t5 in Figure 11) when the bottom brush 51 separates from the substrate W after cleaning the central region R1 of the bottom surface, may be set higher than the rotational speed when the bottom brush 51 is in contact with the central region R1 of the bottom surface and cleaning it (referred to as the third rotational speed).

[0106] Alternatively, at the point when the bottom brush 51 separates from the substrate W after cleaning the central region R1 of the bottom surface (time t5 in Figure 11), the bottom brush 51 may rotate at a rotational speed lower than the second rotational speed bv2.

[0107] Furthermore, the rotational speed at the point when the lower brush 51 separates from the substrate W after cleaning the lower central region R1 (time t5 in Figure 11) may be different from the rotational speed at the point when the lower brush 51 contacts the substrate W to clean the lower central region R1 (time t3 in Figure 11).

[0108] As described above, an example is given in which the second rotational speed bv2 of the lower brush 51, corresponding to the contact and separation points of the lower brush 51 from the substrate W, is set higher than the third rotational speed. Figure 15 is a time chart for illustrating the rotational control of the lower brush 51 according to another embodiment. The time chart in Figure 15 corresponds to the time chart in Figure 11 and shows the change in the rotational speed of the lower brush 51 in Figure 1 during the cleaning of the lower surface of the substrate W. The differences between the time chart in Figure 15 and the time chart in Figure 11 will be explained.

[0109] As shown in Figure 15, in this example, the second rotational speed bv2 of the lower brush 51 is set higher than the first rotational speed bv1 and the higher third rotational speed bv3 at the time when the lower brush 51 contacts the substrate W to clean the lower central region R1 (time t3 in Figure 11) and at the time when the lower brush 51 separates from the substrate W after cleaning the lower central region R1 (time t5 in Figure 11). For example, if the third rotational speed bv3 is 150 rpm, the second rotational speed bv2 is For example, set it to between 200 rpm and 250 rpm.

[0110] As described above, the degree of residue of contaminants due to contact and separation of the lower brush 51 decreases when the relative speed difference between the lower brush 51 and the substrate W is large. Therefore, according to the example in Figure 15, the degree of residue of contaminants due to contact and separation of the lower brush 51 is further reduced.

[0111] (c) In the substrate cleaning apparatus 1 according to the above embodiment, a gap region R5 is defined in the substrate W. As a result, when cleaning the central region R1 of the lower surface of the substrate W held by the upper holding devices 10A and 10B, the lower brush 51 does not come into contact with the outer edge of the substrate W. However, the present invention is not limited thereto. A gap region R5 does not have to be defined in the substrate W.

[0112] (d) In the substrate cleaning apparatus 1 according to the above embodiment, the central region R1 on the lower surface of the substrate W is cleaned by the movement of the lower brush 51 relative to the fixed substrate W, but the present invention is not limited thereto. For example, the central region R1 on the lower surface of the substrate W may be cleaned by a holding device that holds the outer peripheral edge of the substrate W moving and rotating the substrate W relative to the lower brush 51.

[0113] (e) In the substrate cleaning apparatus 1 according to the above embodiment, both the central lower surface region R1 and the outer lower surface region R2 of the substrate W are cleaned by the lower surface cleaning apparatus 50, but the present invention is not limited thereto. Configurations for cleaning the central lower surface region R1 of the substrate W and configurations for cleaning the outer lower surface region R2 of the substrate W may be provided separately.

[0114] 8. Correspondence between each component of the claim and each part of the embodiment The following describes examples of the correspondence between each component of the claims and each element of the embodiments, but the present invention is not limited to the following examples. Various other elements having the configuration or function described in the claims can also be used as each component of the claims.

[0115] In the above embodiment, the upper holding devices 10A and 10B are examples of the first substrate holding part, the lower brush 51 is an example of a cleaning tool, and the base device 30 and the lifting and rotating support part 54 are examples of relative moving parts. Control unit 9 is an example of a control unit. The lower central region R1 is an example of the lower central region, the contact region R3 is an example of the first sub-region, the separated region R4 is an example of the second sub-region, the contact period is an example of the cleaning tool contact period, and the substrate cleaning device 1 is an example of the substrate cleaning device.

[0116] Furthermore, the lower holding device 20 is an example of a second substrate holding part, the lower outer region R2 is an example of a lower outer region, time points t3 to t4 during the cleaning of the lower surface of the substrate W shown in Figures 8 to 12 are an example of a first period, and time points t4 to t5 during the cleaning of the lower surface of the substrate W shown in Figures 8 to 12 are an example of a second period.

[0117] Furthermore, the lifting and rotating support unit 54 is an example of the cleaning tool rotation drive unit, time t3 during the cleaning of the lower surface of the substrate W shown in Figures 8 to 12 is an example of the first time point, time t5 during the cleaning of the lower surface of the substrate W shown in Figures 8 to 12 is an example of the second time point, and the gap region R5 is an example of the gap region.

[0118] 9. Summary of Embodiments (Paragraph 1) The substrate cleaning apparatus relating to Paragraph 1 is: A first substrate holding portion that holds the outer edge of the substrate, A cleaning tool that contacts the lower surface of the substrate and cleans the lower surface of the substrate, The device comprises a relative movement unit that moves the substrate held by the first substrate holding unit and the cleaning tool relative to each other, The aforementioned relative moving part is, When cleaning of the central region of the lower surface of the substrate is initiated, the cleaning tool, which is separated from the lower surface of the substrate, contacts the first partial region of the lower surface of the substrate. Furthermore, when cleaning of the central region of the lower surface of the substrate is completed, the cleaning tool, which is in contact with the lower surface of the substrate, is separated from the second partial region on the lower surface of the substrate. Furthermore, the cleaning tool contacts the central region of the lower surface of the substrate for at least a portion of the cleaning tool contact period, from the time the cleaning tool contacts the lower surface of the substrate until it separates from it. Move the substrate held by the first substrate holding part and at least one of the cleaning tool, At least one of the first and second subregions does not overlap with the central region of the lower surface of the substrate.

[0119] When a cleaning tool that is separated from the underside of the substrate comes into contact with a portion of the underside of the substrate, contaminants caused by the contact of the cleaning tool are likely to remain in that portion of the substrate. Furthermore, when a cleaning tool that is in contact with the substrate separates from a portion of the underside of the substrate, contaminants caused by the separation of the cleaning tool are likely to remain in that portion of the substrate.

[0120] In this substrate cleaning apparatus, the cleaning tool contacts the central region of the underside of the substrate for at least a portion of the cleaning tool contact period. As a result, the central region of the underside of the substrate is cleaned. Furthermore, at least one of the first and second sub-regions does not overlap with the central region of the underside of the substrate. As a result, less contaminant remains in the central region of the underside of the substrate after cleaning compared to when the first and second sub-regions overlap with the central region of the underside of the substrate. Therefore, the cleanliness of the central region of the underside of the substrate after cleaning is improved.

[0121] (Article 2) In the substrate cleaning apparatus described in Article 1, The aforementioned substrate cleaning apparatus is After cleaning the central lower surface region of the substrate with the cleaning tool, the device further includes a second substrate holding unit that rotates the substrate around a vertical axis while adsorbing and holding the central lower surface region, The relative moving part moves the substrate, which is held and rotated by the second substrate holding part, and the cleaning tool relative to each other so that the cleaning tool contacts the outer lower surface region surrounding the central lower surface region of the substrate. At least one of the first and second sub-regions may overlap with a portion of the lower outer region of the substrate.

[0122] In this case, after cleaning the central region of the underside of the substrate, the outer region of the underside of the substrate is cleaned while the central region is held in place by the second substrate holding unit. As a result, even if contaminants remain in at least one of the first and second subregions after cleaning the central region of the underside of the substrate, those contaminants are removed when the outer region of the underside of the substrate is cleaned. Therefore, the overall cleanliness of the underside of the substrate is improved after cleaning both the central and outer regions of the underside.

[0123] Furthermore, with the above configuration, the central region of the lower surface maintains a high degree of cleanliness when the outer region of the lower surface of the substrate is cleaned. Therefore, even when multiple substrates are cleaned sequentially, the occurrence of cross-contamination between multiple substrates via the second substrate holding portion is suppressed.

[0124] (Article 3) In the substrate cleaning apparatus described in Article 1 or Article 2, The first partial region does not overlap with the central region of the lower surface. The relative moving part may move the cleaning tool from the first partial region toward the central region of the lower surface during the first period of the cleaning tool contact period. In this case, since the first partial region does not overlap with the central region of the lower surface of the substrate, the residue of contaminants caused by contact with the cleaning tool in the central region of the lower surface of the substrate after cleaning is suppressed.

[0125] (Article 4) In the substrate cleaning apparatus described in Article 1 or Article 2, The second sub-region does not overlap with the central region of the lower surface. The relative moving part may move the cleaning tool from the central lower surface region toward the second partial region during the second period of the cleaning tool contact period. In this case, since the second partial region does not overlap with the central lower surface region of the substrate, the retention of contaminants in the central lower surface region after cleaning the central lower surface region of the substrate due to the separation of the cleaning tool is suppressed.

[0126] (Article 5) In the substrate cleaning apparatus described in Article 1 or Article 2, Each of the first and second subregions does not overlap with the central region of the lower surface. The aforementioned relative moving part is, During the first period of the cleaning tool contact period, the cleaning tool is moved from the first partial region toward the central region of the lower surface. During the second period of the cleaning tool contact period, the cleaning tool may be moved from the central region of the lower surface toward the second partial region.

[0127] In this case, since the first and second sub-regions do not overlap with the central region of the underside of the substrate, the residue of contaminants caused by contact and separation of the cleaning tool in the central region of the underside of the substrate after cleaning is suppressed.

[0128] (Item 6) In a substrate cleaning apparatus described in any one of items 1 to 5, The substrate cleaning apparatus further comprises a cleaning tool rotation drive unit that rotates the cleaning tool around a vertical axis, The first substrate holding portion is configured to hold the outer peripheral edge of the substrate without rotating the substrate, The cleaning tool rotation drive unit may rotate the cleaning tool at a first time when the cleaning tool contacts the first partial region of the substrate, at a second time when the cleaning tool moves away from the second partial region of the substrate, and during the cleaning tool contact period.

[0129] In this case, the underside of the substrate, which is fixed in a fixed position, can be efficiently cleaned. Furthermore, a relative speed difference can be created between the substrate and the cleaning tool at the first and second time points. This reduces the amount of contaminants remaining on the underside of the substrate due to contact and separation of the cleaning tool.

[0130] (Item 7) In a substrate cleaning apparatus described in any one of items 1 to 6, The relative moving part may move the cleaning tool during the cleaning tool contact period such that a gap area is formed between the first partial region and the outer peripheral edge of the substrate, and between the second partial region and the outer peripheral edge of the substrate, where the cleaning tool does not come into contact.

[0131] In this case, when cleaning the central region of the underside of the substrate, contaminants removed by the cleaning tool are prevented from spreading from the outer edges of the substrate to the top surface. Therefore, a decrease in the cleanliness of the outer edges of the substrate and the top surface of the substrate is prevented.

[0132] (Paragraph 8) The substrate cleaning method relating to Paragraph 8 is: The first step is to hold the outer edge of the substrate with the first substrate holding part, The steps include bringing the cleaning tool into contact with the lower surface of the substrate and cleaning the lower surface of the substrate, The process includes the step of moving the substrate held by the first substrate holding portion and the cleaning tool relative to each other, The step of moving the substrate held by the first substrate holding part and the cleaning tool relative to each other is: When cleaning of the central region of the lower surface of the substrate is initiated, the cleaning tool, which is separated from the lower surface of the substrate, contacts the first partial region of the lower surface of the substrate. Furthermore, when cleaning of the central region of the lower surface of the substrate is completed, the cleaning tool, which is in contact with the lower surface of the substrate, is separated from the second partial region on the lower surface of the substrate. Furthermore, the cleaning tool contacts the central region of the lower surface of the substrate for at least a portion of the cleaning tool contact period, from the time the cleaning tool contacts the lower surface of the substrate until it separates from it. This includes moving at least one of the substrate held by the first substrate holding portion and the cleaning tool, At least one of the first and second subregions does not overlap with the central region of the lower surface of the substrate.

[0133] In this substrate cleaning method, the cleaning tool contacts the central region of the underside of the substrate for at least a portion of the cleaning tool contact period. As a result, the central region of the underside of the substrate is cleaned. In addition, at least one of the first and second sub-regions does not overlap with the central region of the underside of the substrate. As a result, less contaminant remains in the central region of the underside of the substrate after cleaning compared to when the first and second sub-regions overlap with the central region of the underside of the substrate. Therefore, the cleanliness of the central region of the underside of the substrate after cleaning is improved.

[0134] (Section 9) In the substrate cleaning method described in Section 8, The aforementioned substrate cleaning method is After cleaning the central lower surface region of the substrate with the cleaning tool, the substrate is rotated around a vertical axis while the central lower surface region is held in place by a second substrate holding unit. The method further includes the step of moving the substrate held by the second substrate holding portion and the cleaning tool relative to each other so that the cleaning tool contacts the lower outer region surrounding the lower central region of the substrate, At least one of the first and second sub-regions may overlap with a portion of the lower outer region of the substrate.

[0135] In this case, after cleaning the central region of the underside of the substrate, the outer region of the underside of the substrate is cleaned while the central region is held in place by the second substrate holding unit. As a result, even if contaminants remain in at least one of the first and second subregions after cleaning the central region of the underside of the substrate, those contaminants are removed when the outer region of the underside of the substrate is cleaned. Therefore, the overall cleanliness of the underside of the substrate is improved after cleaning both the central and outer regions of the underside.

[0136] Furthermore, with the above configuration, the central region of the lower surface maintains a high degree of cleanliness when the outer region of the lower surface of the substrate is cleaned. Therefore, even when multiple substrates are cleaned sequentially, the occurrence of cross-contamination between multiple substrates via the second substrate holding portion is suppressed.

[0137] (Paragraph 10) In the substrate cleaning method described in paragraph 8 or 9, The first partial region does not overlap with the central region of the lower surface. The step of moving the substrate held by the first substrate holding portion and the cleaning tool relative to each other may include, during the first period of the cleaning tool contact period, moving the cleaning tool from the first partial region toward the central region of the lower surface.

[0138] In this case, since the first sub-region does not overlap with the central region of the underside of the substrate, the residue of contaminants caused by contact with the cleaning tool in the central region of the underside of the substrate after cleaning is suppressed.

[0139] (Paragraph 11) In the substrate cleaning method described in paragraph 8 or 9, The second sub-region does not overlap with the central region of the lower surface. The step of moving the substrate held by the first substrate holding portion and the cleaning tool relative to each other may include, during the second period of the cleaning tool contact period, moving the cleaning tool from the central region of the lower surface toward the second partial region.

[0140] In this case, since the second sub-region does not overlap with the central region of the underside of the substrate, the retention of contaminants in the central region of the underside of the substrate due to the separation of the cleaning tools after cleaning is suppressed.

[0141] (Paragraph 12) In the substrate cleaning method described in paragraph 8 or 9, Each of the first and second subregions does not overlap with the central region of the lower surface. The step of moving the substrate held by the first substrate holding part and the cleaning tool relative to each other is: During the first period of the cleaning tool contact period, the cleaning tool is moved from the first partial region toward the central region of the lower surface, The cleaning tool may be moved from the central region of the lower surface toward the second partial region during the second period of the cleaning tool contact period.

[0142] In this case, since the first and second sub-regions do not overlap with the central region of the underside of the substrate, the residue of contaminants caused by contact and separation of the cleaning tool in the central region of the underside of the substrate after cleaning is suppressed.

[0143] (Item 13) In the substrate cleaning method described in any one of items 8 to 12, The substrate cleaning method further includes the step of rotating the cleaning tool around an axis in the vertical direction, The first substrate holding portion is configured to hold the outer peripheral edge of the substrate without rotating the substrate, The step of rotating the cleaning tool may include rotating the cleaning tool at a first time when the cleaning tool contacts the first partial region of the substrate, at a second time when the cleaning tool moves away from the second partial region of the substrate, and during the cleaning tool contact period.

[0144] In this case, the underside of the substrate, which is fixed in a fixed position, can be efficiently cleaned. Furthermore, a relative speed difference can be created between the substrate and the cleaning tool at the first and second time points. This reduces the amount of contaminants remaining on the underside of the substrate due to contact and separation of the cleaning tool.

[0145] (Item 14) In the substrate cleaning method described in any one of items 8 to 13, The step of moving the cleaning tool may include moving the cleaning tool such that, during the cleaning tool contact period, a gap area is formed between the first partial region and the outer peripheral edge of the substrate, and between the second partial region and the outer peripheral edge of the substrate, where the cleaning tool does not come into contact.

[0146] In this case, when cleaning the central region of the underside of the substrate, contaminants removed by the cleaning tool are prevented from spreading from the outer edges of the substrate to the top surface. Therefore, a decrease in the cleanliness of the outer edges of the substrate and the top surface of the substrate is prevented.

[0147] According to the substrate cleaning apparatus of the above embodiment, the cleanliness of the central region of the lower surface of the substrate after cleaning is improved, thereby improving the yield of products obtained by substrate processing. Consequently, unnecessary substrate processing is reduced, enabling energy savings in substrate processing. Furthermore, it is not necessary to set a long cleaning period for the lower surface of the substrate in order to improve the cleanliness of the lower surface of the substrate. This reduces the use of unnecessary chemicals, etc., and contributes to reducing pollution of the global environment. [Explanation of Symbols]

[0148] 1... Circuit board cleaning device, 2... Unit housing, 2x... Loading / unloading port, 9... Control unit, 10A, 10B... Upper holding device, 11A, 11B... Lower chuck, 12A, 12B... Upper chuck, 20... Lower holding device, 21... Suction holding part, 30... Base device, 31... Linear guide, 32... Movable base, 40... Transfer device, 41... Support pin, 50... Bottom cleaning device, 51... Bottom brush, 52... Liquid nozzle, 53... Gas ejection part, 54... Lifting / rotating support part, 60... Cup Device, 61...Cup, 70...Top surface cleaning device, 71...Rotating support shaft, 72, 82...Arm, 73...Spray nozzle, 80...End cleaning device, 81...Rotating support shaft, 83...Bevel brush, 90...Opening / closing device, 91...Shutter, 100...Drying device, P1...First horizontal position, P2...Second horizontal position, P3...Third horizontal position, R1...Bottom central region, R2...Bottom outer region, R3...Contact region, R4...Separated region, R5...Gap region, W...Substrate, WC...Center

Claims

1. A first substrate holding portion that holds the outer edge of the substrate without rotating the substrate, A second substrate holding unit that holds the central region of the lower surface of the substrate by suction and rotates the substrate around a vertical axis, A cleaning tool that contacts the lower surface of the substrate and cleans the lower surface of the substrate, The substrate held by the first substrate holding portion and the cleaning tool are configured to be able to move relative to each other, and the substrate held and rotated by the second substrate holding portion and the cleaning tool are configured to be able to move relative to each other. It includes a control unit, The control unit controls the relative movement unit, At the start of cleaning the central lower region of the substrate, the cleaning tool, which is separated from the lower surface of the substrate, contacts a first partial region outside the central lower region of the substrate. At the end of cleaning the central lower region of the substrate, the cleaning tool, which is in contact with the lower surface of the substrate, separates from a second partial region outside the central lower region of the substrate. At least one of the substrate and the cleaning tool, held by the first substrate holding portion, is moved such that the cleaning tool contacts the central lower region of the substrate for at least a portion of the cleaning tool contact period from the time the cleaning tool contacts the lower surface of the substrate until it separates from it. Furthermore, after cleaning the central lower surface region of the substrate with the cleaning tool, the substrate held and rotated by the second substrate holding portion and the cleaning tool are moved so that the cleaning tool contacts the outer lower surface region of the substrate that surrounds the central lower surface region of the substrate and includes at least a part of the first partial region and at least a part of the second partial region.

2. The substrate cleaning apparatus according to claim 1, wherein the relative moving part moves the cleaning tool from the first partial region toward the central region of the lower surface during a first period of the cleaning tool contact period.

3. The substrate cleaning apparatus according to claim 2, wherein the relative moving part moves the cleaning tool from the central region of the lower surface toward the second partial region during a second period of the cleaning tool contact period.

4. The cleaning tool is further provided with a cleaning tool rotation drive unit that rotates the cleaning tool around an axis in the vertical direction, The first substrate holding portion is configured to hold the outer peripheral edge of the substrate without rotating the substrate, The substrate cleaning apparatus according to any one of claims 1 to 3, wherein the cleaning tool rotation drive unit rotates the cleaning tool at a first time when the cleaning tool contacts the first partial region of the substrate, at a second time when the cleaning tool separates from the second partial region of the substrate, and during the cleaning tool contact period.

5. The substrate cleaning apparatus according to any one of claims 1 to 3, wherein the relative moving part moves the cleaning tool during the cleaning tool contact period such that a gap area is formed between the first partial region and the outer peripheral edge of the substrate, and between the second partial region and the outer peripheral edge of the substrate, where the cleaning tool does not come into contact.

6. The steps include: holding the outer edge of the substrate with the first substrate holding part without rotating the substrate; The steps include bringing the cleaning tool into contact with the lower surface of the substrate and cleaning the lower surface of the substrate, A step of moving the substrate held by the first substrate holding part and the cleaning tool relative to each other, The second substrate holding portion holds the central region of the lower surface of the substrate by suction, and rotates the substrate around a vertical axis. The process includes the step of moving the substrate held by the second substrate holding portion and the cleaning tool relative to each other, The step of moving the substrate held by the first substrate holding portion and the cleaning tool relative to each other is: The process involves moving at least one of the substrate held by the first substrate holding portion and the cleaning tool so that when cleaning of the central lower surface region of the substrate begins, the cleaning tool, which is separated from the lower surface of the substrate, contacts a first partial region outside the central lower surface region of the substrate, and when cleaning of the central lower surface region of the substrate ends, the cleaning tool, which is in contact with the lower surface of the substrate, separates from a second partial region outside the central lower surface region of the substrate, and so that the cleaning tool contacts the central lower surface region of the substrate for at least a portion of the cleaning tool contact period from when the cleaning tool contacts the lower surface of the substrate until it separates from it. The step of moving the substrate held by the second substrate holding portion and the cleaning tool relative to each other is: A method for cleaning a substrate, comprising cleaning the central lower surface region of the substrate with the cleaning tool, and then moving at least one of the substrate, which is held and rotated by the second substrate holding portion, and the cleaning tool, so that the cleaning tool contacts the outer lower surface region of the substrate that surrounds the central lower surface region of the substrate and includes at least a part of the first partial region and at least a part of the second partial region.

7. The substrate cleaning method according to claim 6, wherein the step of moving the substrate held by the first substrate holding portion and the cleaning tool relative to each other includes, during a first period of the cleaning tool contact period, moving the cleaning tool from the first partial region toward the lower central region.

8. The substrate cleaning method according to claim 7, wherein the step of moving the substrate held by the first substrate holding portion and the cleaning tool relative to each other includes, during a second period of the cleaning tool contact period, moving the cleaning tool from the central region of the lower surface toward the second partial region.

9. The step further includes rotating the cleaning tool around an axis in the vertical direction, The first substrate holding portion is configured to hold the outer peripheral edge of the substrate without rotating the substrate, The substrate cleaning method according to any one of claims 6 to 8, wherein the step of rotating the cleaning tool includes rotating the cleaning tool at a first time when the cleaning tool contacts the first partial region of the substrate, at a second time when the cleaning tool moves away from the second partial region of the substrate, and during the cleaning tool contact period.

10. The substrate cleaning method according to any one of claims 6 to 8, wherein the step of moving the cleaning tool includes moving the cleaning tool such that, during the period of contact with the cleaning tool, a gap area is formed between the first partial region and the outer peripheral edge of the substrate, and between the second partial region and the outer peripheral edge of the substrate, where the cleaning tool does not come into contact.

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