Substrate cleaning method and substrate cleaning device

Abstract

The present invention relates to a substrate cleaning method and a substrate cleaning device for cleaning a substrate such as a wafer. The substrate cleaning method comprises: a first cleaning step for cleaning a substrate (W) while forming liquid pools (L) of a cleaning liquid on surfaces (2a, 2b) of the substrate (W) by individually rotating roll cleaning tools (8, 9), which extend in the radial direction of the substrate (W), in a first rotation direction (D1) so that cleaning surfaces (M) of the roll cleaning tools (8, 9) move in a direction opposite to a movement direction (Dw) of the surfaces (2a, 2b) of the substrate (W) while keeping the cleaning surfaces (M) of the roll cleaning tools (8, 9) in contact with the respective surfaces (2a, 2b) of the substrate (W); and a second cleaning step for cleaning the substrate (W) while discharging the cleaning liquid from the surfaces (2a, 2b) of the substrate (W) by individually rotating the roll cleaning tools (8, 9) in a second rotation direction (D2) opposite to the first rotation direction (D1) after the first cleaning step.

Description

Substrate cleaning method and substrate cleaning apparatus

[0001] The present invention relates to a substrate cleaning method and a substrate cleaning apparatus for cleaning a substrate such as a wafer.

[0002] In the manufacturing process of semiconductor devices, various films with different physical properties are formed on a silicon substrate, and fine metal wirings are formed by subjecting these films to various processes. For example, in the damascene wiring formation process, wiring grooves are formed in the film, a metal such as Cu is embedded in the wiring grooves, and then excess metal is removed by chemical mechanical polishing (CMP) to form metal wirings. After polishing the substrate, the substrate is usually cleaned by a substrate cleaning apparatus. The cleaning of the substrate is performed by rotating the substrate and bringing a roll cleaning tool such as a roll sponge into sliding contact with the substrate while supplying a cleaning liquid such as a chemical solution from a cleaning liquid nozzle to the substrate.

[0003] Japanese Patent Laid-Open No. 2023-28395

[0004] In order to clean the substrate with high cleaning power, it is necessary to bring the roll cleaning tool into sliding contact with the substrate in a state where the cleaning liquid is sufficiently present on the substrate. On the other hand, since the cleaning liquid on the substrate contains cleaning debris such as particles removed from the substrate, it is desirable to discharge such cleaning liquid from the substrate as quickly as possible.

[0005] Therefore, the present invention provides a substrate cleaning method and a substrate cleaning apparatus capable of cleaning a substrate such as a wafer with high cleaning power and quickly removing the cleaning liquid used for cleaning from the substrate.

[0006] In one embodiment, a substrate cleaning method is provided, which includes holding and rotating a substrate, supplying a cleaning solution to the surface of the substrate, and cleaning the substrate by pressing a roll cleaning tool, which extends radially to the substrate, against the surface of the substrate while rotating the roll cleaning tool, wherein the cleaning of the substrate is performed by bringing the cleaning surface of the roll cleaning tool into contact with the surface of the substrate, and rotating the roll cleaning tool in a first rotational direction in which the cleaning surface of the roll cleaning tool moves in the direction opposite to the direction of movement of the surface of the substrate, thereby cleaning the substrate while forming a reservoir of the cleaning solution on the surface of the substrate; and a second cleaning step, after the first cleaning step, rotating the roll cleaning tool in a second rotational direction opposite to the first rotational direction, thereby cleaning the substrate while discharging the cleaning solution from the surface of the substrate.

[0007] In one embodiment, the second pressing force applied to the roll cleaning tool in the second cleaning step is smaller than the first pressing force applied to the roll cleaning tool in the first cleaning step. In one embodiment, the cleaning liquid is supplied to a region of the surface of the substrate located upstream of the cleaning surface of the roll cleaning tool in the direction of travel of the surface of the substrate. In one embodiment, the rotational speed of the substrate in the second cleaning step is greater than the rotational speed of the substrate in the first cleaning step. In one embodiment, the rotational speed of the roll cleaning tool in the second cleaning step is greater than or equal to the rotational speed of the roll cleaning tool in the first cleaning step. In one embodiment, the axial length of the roll cleaning tool is equal to or greater than the radius of the substrate.

[0008] In one embodiment, the system includes a substrate holding device for holding and rotating a substrate, a cleaning liquid nozzle for supplying cleaning liquid to the surface of the substrate, a roll cleaning tool extending radially from the substrate, a cleaning tool rotation mechanism for rotating the roll cleaning tool about its axis, a cleaning tool pressing mechanism for pressing the roll cleaning tool against the surface of the substrate, and an operation control unit for controlling the operation of the substrate holding device, the cleaning liquid nozzle, the cleaning tool rotation mechanism, and the cleaning tool pressing mechanism. The operation control unit gives commands to the substrate holding device to rotate the substrate, to the cleaning liquid nozzle to supply cleaning liquid to the surface of the substrate, and to the cleaning tool pressing mechanism to control the operation of the roll cleaning tool. A substrate cleaning apparatus is provided, wherein the cleaning tool's cleaning surface is brought into contact with the surface of the substrate, and a command is given to the cleaning tool rotation mechanism to rotate the roll cleaning tool in a first rotational direction, thereby performing a first cleaning step in which the substrate is cleaned while forming a reservoir of cleaning liquid on the surface of the substrate; and a command is given to the cleaning tool rotation mechanism to rotate the roll cleaning tool in a second rotational direction opposite to the first rotational direction, thereby performing a second cleaning step in which the substrate is cleaned while discharging the cleaning liquid from the surface of the substrate, wherein the first rotational direction is the direction in which the cleaning surface of the roll cleaning tool moves in the direction opposite to the direction in which the surface of the substrate moves.

[0009] In one embodiment, in the first cleaning step, the cleaning tool pressing mechanism is configured to apply a first pressing force to the roll cleaning tool, and in the second cleaning step, the cleaning tool pressing mechanism is configured to apply a second pressing force to the roll cleaning tool that is smaller than the first pressing force. In one embodiment, the cleaning liquid nozzle is arranged to supply the cleaning liquid to a region of the surface of the substrate located upstream of the cleaning surface of the roll cleaning tool in the direction of travel of the surface of the substrate. In one embodiment, the rotational speed of the substrate in the second cleaning step is greater than the rotational speed of the substrate in the first cleaning step. In one embodiment, the rotational speed of the roll cleaning tool in the second cleaning step is greater than or equal to the rotational speed of the roll cleaning tool in the first cleaning step. In one embodiment, the axial length of the roll cleaning tool is equal to or greater than the radius of the substrate.

[0010] The substrate cleaning method includes a first cleaning step in which the substrate is cleaned while forming a reservoir of cleaning solution on the substrate surface, and a second cleaning step in which the substrate is cleaned after the first cleaning step while discharging the cleaning solution from the substrate surface. Therefore, the substrate can be cleaned with high cleaning power in the first cleaning step, and then the cleaning solution used for cleaning can be quickly removed from the substrate in the second cleaning step.

[0011] This is a plan view showing one embodiment of a substrate cleaning apparatus. This is a side view of the substrate cleaning apparatus shown in Figure 1. This is a flowchart showing one embodiment of a substrate cleaning method using the substrate cleaning apparatus. This is a diagram showing one embodiment of a first cleaning step and a second cleaning step. This is a plan view showing a liquid reservoir formed on the first surface of the substrate in the first cleaning step. This is a diagram to explain the cleaning effect when cleaning a substrate while forming a liquid reservoir. This is a diagram illustrating an embodiment in which the first roll cleaning tool is separated from the first surface of the substrate in the second cleaning step. This is a plan view showing another embodiment of the substrate cleaning apparatus. This is a plan view showing the substrate cleaning apparatus shown in Figure 8 performing the second cleaning step. This is a side view showing yet another embodiment of the substrate cleaning apparatus. This is a side view showing yet another embodiment of the substrate cleaning apparatus.

[0012] Embodiments of the present invention will now be described with reference to the drawings. Figure 1 is a plan view showing one embodiment of the substrate cleaning apparatus 1, and Figure 2 is a side view of the substrate cleaning apparatus 1 shown in Figure 1. The substrate cleaning apparatus 1 is a device for cleaning substrates W such as wafers. Specific examples of substrates W include wafers used in semiconductor devices and circular substrates. In the embodiments described below, a circular wafer is used as the substrate W.

[0013] The substrate cleaning apparatus 1 includes a substrate holding device 5 for holding and rotating the substrate W, a first roll cleaning tool 8 that contacts the first surface 2a of the substrate W, a second roll cleaning tool 9 that contacts the second surface 2b of the substrate W, a first cleaning liquid nozzle 11 that supplies cleaning liquid toward the first surface 2a of the substrate W, a second cleaning liquid nozzle 12 that supplies cleaning liquid toward the second surface 2b of the substrate W, a first cleaning tool rotation mechanism 15 that rotates the first roll cleaning tool 8 around its axis, and a second cleaning tool rotation mechanism 16 that rotates the second roll cleaning tool 9 around its axis. In Figure 1, some of the components of the substrate cleaning apparatus 1 are not shown.

[0014] The substrate holding device 5 is equipped with a plurality of holding rollers 6 that contact the peripheral edge of the substrate W and rotate the substrate W about its central axis CL. The central axis CL shown in Figure 2 is an imaginary line representing the axis of rotation of the substrate W by the substrate holding device 5. The central axis CL of the substrate W passes through the center of the substrate W held by the plurality of holding rollers 6. The first surface 2a of the substrate W is, for example, a device surface on which a device is formed or is planned to be formed. The second surface 2b of the substrate W is, for example, a non-device surface on which no device is formed or is not planned to be formed. The second surface 2b is on the opposite side from the first surface 2a.

[0015] Multiple holding rollers 6 are arranged around a central axis CL. When holding the substrate W, the distance of the multiple holding rollers 6 from the central axis CL is the same. In this embodiment, four holding rollers 6 are arranged, but three or five or more holding rollers 6 may be arranged. Multiple holding rollers 6 are connected to a roller rotating device (not shown) and are rotated in the same direction at the same rotational speed by the roller rotating device. In this embodiment, the substrate holding device 5 is configured to hold the substrate W in a horizontal position.

[0016] As shown in Figure 2, each retaining roller 6 has a substrate retaining groove 6a formed on its outer circumferential surface. The substrate retaining groove 6a is an annular groove extending in the circumferential direction on the outer circumferential surface of each retaining roller 6. The width of the substrate retaining groove 6a is greater than the thickness of the substrate W, and the peripheral edge of the substrate W contacts the multiple substrate retaining grooves 6a of the multiple retaining rollers 6. These substrate retaining grooves 6a can stabilize the orientation of the rotating substrate W.

[0017] The first roll cleaning tool 8 and the second roll cleaning tool 9 each extend radially across the substrate W. As shown in Figure 2, the first roll cleaning tool 8 is connected to the first cleaning tool rotation mechanism 15 via a first rotation shaft 25. The second roll cleaning tool 9 is connected to the second cleaning tool rotation mechanism 16 via a second rotation shaft 26. The first roll cleaning tool 8 and the second roll cleaning tool 9 are rotated by the first cleaning tool rotation mechanism 15 and the second cleaning tool rotation mechanism 16, respectively, around their respective axes. The axis of the first rotation shaft 25 coincides with the central axis R1 of the first roll cleaning tool 8, and the axis of the second rotation shaft 26 coincides with the central axis R2 of the second roll cleaning tool 9.

[0018] The first roll cleaning tool 8 is mounted around the first rotating shaft 25 and has a cylindrical shape. The second roll cleaning tool 9 is mounted around the second rotating shaft 26 and has a cylindrical shape. The first roll cleaning tool 8 and the second roll cleaning tool 9 are made of an elastic material such as PU (polyurethane) or PVA (polyvinyl alcohol). However, the material of the first roll cleaning tool 8 and the second roll cleaning tool 9 is not particularly limited.

[0019] The first roll cleaning tool 8 and the second roll cleaning tool 9 may have a plurality of protrusions (also called "nodules") on their surfaces. In one embodiment, the nodules are cylindrical in shape, but the shape of the nodules is not limited thereto. In one embodiment, the nodules are arranged at equal intervals in the axial and circumferential directions of the first roll cleaning tool 8 and the second roll cleaning tool 9.

[0020] In this embodiment, the first roll cleaning tool 8 and the second roll cleaning tool 9 are pressed against the first surface 2a and the second surface 2b of the substrate W while rotating, thereby cleaning the first surface 2a and the second surface 2b, respectively. The first roll cleaning tool 8 contacts the center of the first surface 2a of the substrate W, and the second roll cleaning tool 9 contacts the center of the second surface 2b of the substrate W. In one embodiment, the central axis R1 of the first roll cleaning tool 8 passes through the central axis line CL, and the central axis R2 of the second roll cleaning tool 9 also passes through the central axis line CL.

[0021] The central axis R1 of the first roll cleaning tool 8 extends parallel to the first surface 2a of the substrate W, and the central axis R2 of the second roll cleaning tool 9 extends parallel to the second surface 2b of the substrate W. The axial length of the first roll cleaning tool 8 is equal to or greater than the radius of the substrate W. The axial length of the second roll cleaning tool 9 is equal to or greater than the radius of the substrate W.

[0022] In this embodiment, the outer ends of the first roll cleaning tool 8 and the second roll cleaning tool 9 extend beyond the substrate W. The axial lengths of the first roll cleaning tool 8 and the second roll cleaning tool 9 are greater than the radius of the substrate W. That is, each of the first roll cleaning tool 8 and the second roll cleaning tool 9 extends from its inner end through the center of the substrate W to its outer end. Therefore, as the substrate W rotates once, the first roll cleaning tool 8 and the second roll cleaning tool 9 make contact with the entire first surface 2a and the entire second surface 2b of the substrate W, respectively.

[0023] In this embodiment, the diameter of the cross-section of the first roll cleaning tool 8 and the diameter of the cross-section of the second roll cleaning tool 9 are the same. However, the diameter of the cross-section of the first roll cleaning tool 8 and the diameter of the cross-section of the second roll cleaning tool 9 may be different. That is, the diameter of the cross-section of the second roll cleaning tool 9 may be larger or smaller than the diameter of the cross-section of the first roll cleaning tool 8.

[0024] The first cleaning liquid nozzle 11 is positioned adjacent to the first roll cleaning tool 8, and the second cleaning liquid nozzle 12 is positioned adjacent to the second roll cleaning tool 9. As shown in Figure 1, the first cleaning liquid nozzle 11 is positioned upstream of the first roll cleaning tool 8 in the rotational direction of the substrate W. Similarly, the second cleaning liquid nozzle 12 is positioned upstream of the second roll cleaning tool 9 in the rotational direction of the substrate W. The first cleaning liquid nozzle 11 supplies cleaning liquid to the first surface 2a of the substrate W, which is held and rotated by the substrate holding device 5, and the second cleaning liquid nozzle 12 supplies cleaning liquid to the second surface 2b of the substrate W, which is held and rotated by the substrate holding device 5.

[0025] Examples of cleaning solutions include chemical solutions, pure water, and combinations thereof. In one embodiment, the first cleaning solution nozzle 11 and the second cleaning solution nozzle 12 may each be configured to switch between supplying a chemical solution and supplying pure water. In one embodiment, in addition to the first cleaning solution nozzle 11 and the second cleaning solution nozzle 12 for supplying a chemical solution, a first pure water nozzle and a second pure water nozzle (not shown) may be provided for supplying pure water to the first surface 2a and the second surface 2b of the substrate W, respectively. The first roll cleaning tool 8 and the second roll cleaning tool 9 clean the first surface 2a and the second surface 2b of the substrate W, respectively, in the presence of the cleaning solution.

[0026] In one embodiment, the substrate cleaning apparatus 1 may be configured to include either a first roll cleaning tool 8 or a second roll cleaning tool 9, and to clean either the first surface 2a or the second surface 2b of the substrate W.

[0027] As shown in Figure 2, the first cleaning tool rotation mechanism 15 is connected to the first roll cleaning tool 8 via a first rotating shaft 25, and the second cleaning tool rotation mechanism 16 is connected to the second roll cleaning tool 9 via a second rotating shaft 26. The substrate cleaning apparatus 1 includes a first support part 21 that rotatably supports the first roll cleaning tool 8, and a second support part 22 that rotatably supports the second roll cleaning tool 9. The first cleaning tool rotation mechanism 15 is fixed to the first support part 21, and the second cleaning tool rotation mechanism 16 is fixed to the second support part 22. The specific configurations of the first cleaning tool rotation mechanism 15 and the second cleaning tool rotation mechanism 16 are not particularly limited, but examples include an electric motor, or a combination of an electric motor and a torque transmission mechanism (e.g., a belt or gears).

[0028] The substrate cleaning apparatus 1 includes a first cleaning tool pressing mechanism 31 that presses a first roll cleaning tool 8 against a first surface 2a, a second cleaning tool pressing mechanism 32 that presses a second roll cleaning tool 9 against a second surface 2b, a support shaft 35 connected to the first cleaning tool pressing mechanism 31, and a support arm 36 connected to the upper end of the support shaft 35.

[0029] The first cleaning tool pressing mechanism 31 is connected to the first roll cleaning tool 8 via a support shaft 35, a support arm 36, and a first support portion 21. As shown by the arrows in Figure 2, the first cleaning tool pressing mechanism 31 moves the first roll cleaning tool 8, the first cleaning tool rotation mechanism 15, the first support portion 21, and the support arm 36 together in a direction toward the first surface 2a of the substrate W and in a direction toward away from the first surface 2a. The first cleaning tool pressing mechanism 31 presses the first roll cleaning tool 8 against the first surface 2a by moving the first roll cleaning tool 8 toward the first surface 2a. The first cleaning tool pressing mechanism 31 moves the first roll cleaning tool 8 away from the first surface 2a by moving the first roll cleaning tool 8 toward away from the first surface 2a.

[0030] The second cleaning tool pressing mechanism 32 is connected to the second roll cleaning tool 9 via the second support portion 22. As shown by the arrows in Figure 2, the second cleaning tool pressing mechanism 32 moves the second roll cleaning tool 9, the second cleaning tool rotation mechanism 16, and the second support portion 22 together in a direction toward the second surface 2b of the substrate W and in a direction toward the second surface 2b. The second cleaning tool pressing mechanism 32 presses the second roll cleaning tool 9 against the second surface 2b by moving the second roll cleaning tool 9 toward the second surface 2b. The second cleaning tool pressing mechanism 32 moves the second roll cleaning tool 9 away from the second surface 2b by moving the second roll cleaning tool 9 toward the second surface 2b.

[0031] The specific configurations of the first cleaning tool pressing mechanism 31 and the second cleaning tool pressing mechanism 32 are not particularly limited, but examples include a combination of an air cylinder and a pressure regulator, and a combination of a ball screw mechanism and a servo motor.

[0032] The substrate cleaning apparatus 1 includes a substrate holding device 5, a first cleaning liquid nozzle 11, a second cleaning liquid nozzle 12, a first cleaning tool rotation mechanism 15, a second cleaning tool rotation mechanism 16, a first cleaning tool pressing mechanism 31, and a second cleaning tool pressing mechanism 32, and an operation control unit 40 that controls the operation of these components. The substrate holding device 5, the first cleaning liquid nozzle 11, the second cleaning liquid nozzle 12, the first cleaning tool rotation mechanism 15, the second cleaning tool rotation mechanism 16, the first cleaning tool pressing mechanism 31, and the second cleaning tool pressing mechanism 32 are electrically connected to the operation control unit 40.

[0033] The operation control unit 40 comprises a storage device 40a in which a program is stored, and an arithmetic unit 40b that performs calculations according to the instructions contained in the program. The operation control unit 40 is composed of at least one computer. The storage device 40a comprises a main memory such as random access memory (RAM) and an auxiliary storage device such as a hard disk drive (HDD) or solid state drive (SSD). Examples of the arithmetic unit 40b include a CPU (central processing unit) and a GPU (graphics processing unit). However, the specific configuration of the operation control unit 40 is not limited to these examples.

[0034] Figure 3 is a flowchart illustrating one embodiment of a substrate cleaning method using the substrate cleaning apparatus 1. In step S101, the substrate holding device 5 holds the substrate W and starts rotating the substrate W. In step S102, the first cleaning liquid nozzle 11 and the second cleaning liquid nozzle 12 start supplying cleaning liquid to the first surface 2a and the second surface 2b of the substrate W, respectively. In this embodiment, the cleaning liquid supplied from the first cleaning liquid nozzle 11 and the second cleaning liquid nozzle 12 in step S102 is a chemical solution.

[0035] In step S103, the first cleaning tool rotation mechanism 15 and the second cleaning tool rotation mechanism 16 rotate the first roll cleaning tool 8 and the second roll cleaning tool 9, respectively, and the first cleaning tool pressing mechanism 31 and the second cleaning tool pressing mechanism 32 bring the first roll cleaning tool 8 and the second roll cleaning tool 9 into contact with the first surface 2a and the second surface 2b of the substrate W, respectively. As a result, the first surface 2a and the second surface 2b of the substrate W are cleaned by the first roll cleaning tool 8 and the second roll cleaning tool 9. The cleaning operation of the substrate W by the first roll cleaning tool 8 and the second roll cleaning tool 9 in step S103 includes the first cleaning step and the second cleaning step, which will be described later.

[0036] In step S104, the first cleaning tool pressing mechanism 31 and the second cleaning tool pressing mechanism 32 move the first roll cleaning tool 8 and the second roll cleaning tool 9 away from the first surface 2a and the second surface 2b of the substrate W, respectively, and the first cleaning tool rotation mechanism 15 and the second cleaning tool rotation mechanism 16 stop the rotation of the first roll cleaning tool 8 and the second roll cleaning tool 9, respectively. In step S105, the first cleaning liquid nozzle 11 and the second cleaning liquid nozzle 12 continue to supply cleaning liquid to the first surface 2a and the second surface 2b of the substrate W to perform rinsing. In this embodiment, the cleaning liquid supplied from the first cleaning liquid nozzle 11 and the second cleaning liquid nozzle 12 in step S105 is a chemical solution.

[0037] In step S106, the first cleaning solution nozzle 11 and the second cleaning solution nozzle 12 stop supplying the cleaning solution to the first surface 2a and the second surface 2b of the substrate W. Subsequently, the first cleaning solution nozzle 11 and the second cleaning solution nozzle 12, or a pure water nozzle (not shown), supply pure water to the first surface 2a and the second surface 2b of the substrate W, respectively, to perform a rinse cleaning with pure water. If the cleaning solution supplied from the first cleaning solution nozzle 11 and the second cleaning solution nozzle 12 in steps S102 and S105 is pure water, step S106 is not performed.

[0038] Figure 4 shows one embodiment of the first and second cleaning steps. In step S103 shown in Figure 3 above, the cleaning operation of the substrate W by the first roll cleaning tool 8 and the second roll cleaning tool 9 includes the first cleaning step and the second cleaning step. Since the cleaning operation of the first surface 2a of the substrate W by the first roll cleaning tool 8 and the cleaning operation of the second surface 2b of the substrate W by the second roll cleaning tool 9 are basically the same, the cleaning operation of the first surface 2a of the substrate W by the first roll cleaning tool 8 will be described below. The first cleaning step is a step of cleaning the substrate W while forming a liquid reservoir L of cleaning liquid on the first surface 2a of the substrate W, and the second cleaning step is a step of cleaning the substrate W after the first cleaning step while discharging the cleaning liquid from the first surface 2a of the substrate W.

[0039] In the first cleaning process, the operation control unit 40 is configured to give a command to the first cleaning tool pressing mechanism 31 to bring the cleaning surface M of the first roll cleaning tool 8 into contact with the first surface 2a of the substrate W, and to give a command to the first cleaning tool rotation mechanism 15 to rotate the first roll cleaning tool 8 in the first rotation direction D1. The first rotation direction D1 is the direction in which the cleaning surface M of the first roll cleaning tool 8 moves in the opposite direction to the direction of travel Dw of the first surface 2a of the substrate W. The cleaning surface M of the first roll cleaning tool 8 is the surface that contacts the first surface 2a of the substrate W and extends in the axial direction of the first roll cleaning tool 8. Of the outer surface of the first roll cleaning tool 8, the portion that constitutes the cleaning surface M changes as the first roll cleaning tool 8 rotates.

[0040] The first cleaning liquid nozzle 11 is positioned to supply cleaning liquid to a region on the first surface 2a of the substrate W located upstream of the cleaning surface M of the first roll cleaning tool 8, in the direction of travel Dw of the first surface 2a of the substrate W. Preferably, the cleaning liquid supplied from the first cleaning liquid nozzle 11 spreads throughout the entire axial direction of the first roll cleaning tool 8 upstream of the cleaning surface M of the first roll cleaning tool 8. The type of first cleaning liquid nozzle 11 is not particularly limited, but examples include a nozzle that discharges cleaning liquid from a tubular nozzle or a nozzle that discharges mist-like cleaning liquid from a spray nozzle. For the spray nozzle, a flat pattern nozzle that supplies mist-like cleaning liquid to the first surface 2a of the substrate W in a linear shape, or a full cone pattern nozzle that supplies mist-like cleaning liquid to the first surface 2a of the substrate W in a circular shape can be used. In one embodiment, a plurality of first cleaning liquid nozzles 11 may be provided, or a combination of different types of first cleaning liquid nozzles 11 may be provided. The configuration of the second cleaning liquid nozzle 12 is the same as that of the first cleaning liquid nozzle 11.

[0041] Most of the cleaning fluid supplied from the first cleaning fluid nozzle 11 to the first surface 2a of the substrate W is blocked by the first roll cleaning tool 8, which rotates in the first rotational direction D1. As a result, a liquid reservoir L is formed in the direction of travel Dw of the first surface 2a of the substrate W, located upstream of the cleaning surface M of the first roll cleaning tool 8. The remaining portion of the cleaning fluid supplied to the first surface 2a passes between the first roll cleaning tool 8 and the first surface 2a, or flows along the first roll cleaning tool 8 and flows out of the substrate W.

[0042] In the first cleaning step, the first cleaning tool pressing mechanism 31 applies a first pressing force F1 to the first roll cleaning tool 8. As the first pressing force F1 increases, the contact area between the cleaning surface M of the first roll cleaning tool 8 and the first surface 2a of the substrate W can be increased. Therefore, by making the first pressing force F1 sufficiently large, the amount of cleaning liquid passing between the first roll cleaning tool 8 and the first surface 2a of the substrate W is reduced, making it easier for a liquid reservoir L to form.

[0043] FIG. 5 is a plan view showing a liquid pool L formed on the first surface 2a of the substrate W in the first cleaning step. As shown in FIG. 5, the liquid pool L is formed along the outer surface of the first roll cleaning tool 8 in the axial direction of the first roll cleaning tool 8. In one embodiment, the liquid pool L is formed over the entire length of the first roll cleaning tool 8.

[0044] FIG. 6 is a diagram for explaining the cleaning effect when the substrate W is cleaned while forming the liquid pool L. The cleaning liquid existing on the first surface 2a of the substrate W has a slower flow rate as the distance from the substrate W decreases. The viscous sublayer La of the cleaning liquid shown in FIG. 6 is a portion where the flow of the cleaning liquid is particularly slow (for example, about 20 mm / sec or less). In one embodiment, the viscous sublayer La is a portion having a distance of about 10 μm or less from the substrate W.

[0045] In the presence of the cleaning liquid, when the rotating first roll cleaning tool 8 contacts the first surface 2a of the substrate W, cleaning debris X is generated from the substrate W. When the cleaning debris X enters the viscous sublayer La, it tends to stay in the viscous sublayer La, making it difficult to remove the cleaning debris X from the viscous sublayer La. Further, the cleaning debris X that has entered the viscous sublayer La may reattach to the substrate W. According to the present embodiment, in the first cleaning step, by actively stagnating the flow of the cleaning liquid on the substrate W, the thickness of the liquid pool L is increased, and a liquid pool L sufficiently thicker than the viscous sublayer La can be formed on the first surface 2a. The sufficiently thick liquid pool L disperses the cleaning debris X into a liquid layer Lb that is farther from the substrate W than the viscous sublayer La, making it difficult for the cleaning debris X to enter the viscous sublayer La and facilitating the removal of even the cleaning debris X present in the viscous sublayer La. As a result, the substrate W can be cleaned with a high cleaning power in the first cleaning step. In one embodiment, the liquid pool L has a thickness of 100 μm or more.

[0046] As shown in FIG. 4, after the first cleaning step, in the second cleaning step, the operation control unit 40 gives a command to the first cleaning tool rotation mechanism 15 to rotate the first roll cleaning tool 8 in a second rotation direction D2 opposite to the first rotation direction D1. The second rotation direction D2 is the direction in which the cleaning surface M of the first roll cleaning tool 8 advances in the same direction as the advancing direction Dw of the first surface 2a of the substrate W. Also in the second cleaning step, the first cleaning liquid nozzle 11 supplies the cleaning liquid to a region on the first surface 2a located upstream of the cleaning surface M of the first roll cleaning tool 8 in the advancing direction Dw of the first surface 2a of the substrate W.

[0047] By the first roll cleaning tool 8 rotating in the second rotation direction D2, which is the same as the advancing direction Dw of the first surface 2a of the substrate W, a flow of the cleaning liquid from the upstream side to the downstream side of the cleaning surface M of the first roll cleaning tool 8 is formed in the advancing direction Dw of the first surface 2a. Due to such a flow of the cleaning liquid on the first surface 2a of the substrate W, the cleaning liquid used for cleaning can be quickly discharged from the first surface 2a of the substrate W. As a result, in the second cleaning step, the cleaning liquid used for cleaning can be quickly removed from the substrate W.

[0048] In the present embodiment, in the second cleaning step, the first cleaning tool pressing mechanism 31 applies a second pressing force F2 smaller than the first pressing force F1 to the first roll cleaning tool 8. Most of the cleaning liquid present on the first surface 2a of the substrate W passes between the first roll cleaning tool 8 and the first surface 2a of the substrate W and is moved to the downstream side of the cleaning surface M of the first roll cleaning tool 8 in the advancing direction Dw of the first surface 2a of the substrate W. In the second cleaning step, by applying the second pressing force F2 smaller than the first pressing force F1 to the first roll cleaning tool 8, the contact area between the cleaning surface M of the first roll cleaning tool 8 and the first surface 2a of the substrate W decreases, and the cleaning liquid easily passes between the first roll cleaning tool 8 and the first surface 2a of the substrate W.

[0049] In one embodiment, the second pressing force F2 applied to the first roll cleaning tool 8 in the second cleaning step may be the same as the first pressing force F1 applied to the first roll cleaning tool 8 in the first cleaning step.

[0050] In one embodiment, the rotation speed of the substrate W in the second cleaning step is greater than the rotation speed of the substrate W in the first cleaning step. By making the rotation speed of the substrate W in the second cleaning step greater than the rotation speed of the substrate W in the first cleaning step, the flow of the cleaning liquid from the upstream side to the downstream side of the cleaning surface M in the rotation direction of the substrate W on the cleaning surface M can be accelerated. In one embodiment, the rotation speed of the substrate W in the second cleaning step may be the same as the rotation speed of the substrate W in the first cleaning step.

[0051] In one embodiment, the rotational speed of the first roll cleaning tool 8 in the second cleaning step is equal to or greater than the rotational speed of the first roll cleaning tool 8 in the first cleaning step. By setting the rotational speed of the first roll cleaning tool 8 in the second cleaning step to be equal to or greater than the rotational speed of the first roll cleaning tool 8 in the first cleaning step, the flow of the cleaning liquid from the upstream side to the downstream side of the cleaning surface M in the rotational direction of the substrate W on the cleaning surface M can be accelerated.

[0052] In one embodiment, as shown in Figure 7, during the second cleaning step, the first roll cleaning tool 8 may be in contact with the cleaning liquid on the first surface 2a of the substrate W while being separated from the first surface 2a. That is, the second pressing force F2 may be 0. In this embodiment shown in Figure 7, the cleaning surface M of the first roll cleaning tool 8 is the surface facing the first surface 2a of the substrate W and extends in the axial direction of the first roll cleaning tool 8. As the first roll cleaning tool 8, which is in contact with the cleaning liquid on the first surface 2a, rotates in the same second rotation direction D2 as the direction of travel Dw of the first surface 2a of the substrate W, a flow of cleaning liquid is formed in the direction of travel Dw of the first surface 2a, moving from the upstream side to the downstream side of the cleaning surface M of the first roll cleaning tool 8. In this case, a gap is created between the first roll cleaning tool 8 and the first surface 2a of the substrate W, making it easier for the cleaning liquid to pass between the first roll cleaning tool 8 and the first surface 2a of the substrate W.

[0053] In one embodiment, the first cleaning step may be performed again after the second cleaning step. After the first cleaning step is performed again, the second cleaning step is performed again. In other embodiments, the first cleaning step and the second cleaning step may be repeated multiple times. In all cases, after the final second cleaning step, steps S104 to S106, as described with reference to Figure 3, are performed.

[0054] Figure 8 is a plan view showing another embodiment of the substrate cleaning apparatus 1. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiment described above, so a redundant explanation is omitted. The substrate cleaning apparatus 1 of this embodiment includes two first roll cleaning tools 8A and 8B arranged parallel to the first surface 2a of the substrate W. The first roll cleaning tools 8A and 8B extend in the radial direction of the substrate W. In this embodiment, the axial length of the first roll cleaning tool 8A is greater than the radius of the substrate W. That is, the first roll cleaning tool 8A extends from its inner end through the center of the substrate W to its outer end. The axial length of the first roll cleaning tool 8B is less than the radius of the substrate W. Therefore, as the substrate W rotates around, the entire first surface 2a of the substrate W comes into contact with at least one of the first roll cleaning tools 8A and 8B.

[0055] In this embodiment, the axial directions of the first roll cleaning tool 8A and the first roll cleaning tool 8B coincide, but the arrangement of the first roll cleaning tool 8A and the first roll cleaning tool 8B is not limited to this embodiment, as long as the entire first surface 2a of the substrate W can come into contact with at least one of the first roll cleaning tool 8A and the first roll cleaning tool 8B during one rotation of the substrate W. In one embodiment, the axial direction of the first roll cleaning tool 8A may be inclined with respect to the axial direction of the first roll cleaning tool 8B.

[0056] The substrate cleaning apparatus 1 of this embodiment includes a first cleaning liquid nozzle 11A positioned adjacent to the first roll cleaning tool 8A, and a first cleaning liquid nozzle 11B positioned adjacent to the first roll cleaning tool 8B. The first cleaning liquid nozzle 11A is positioned upstream of the first roll cleaning tool 8A in the rotational direction of the substrate W, and the first cleaning liquid nozzle 11B is positioned upstream of the first roll cleaning tool 8B in the rotational direction of the substrate W. When the substrate cleaning apparatus 1 is viewed from above, the direction of travel Dw1 of the first surface 2a of the substrate W on the cleaning surface of the first roll cleaning tool 8A and the direction of travel Dw2 of the first surface 2a of the substrate W on the cleaning surface of the first roll cleaning tool 8B are opposite directions.

[0057] Figure 8 shows the substrate cleaning apparatus 1 in the first cleaning process. In the first cleaning process, the cleaning surface of the first roll cleaning tool 8A is brought into contact with the first surface 2a of the substrate W, and the first roll cleaning tool 8A is rotated in a first rotational direction Da1 in the opposite direction to the direction of travel Dw1 of the first surface 2a of the substrate W, so that the cleaning surface of the first roll cleaning tool 8A moves. As a result, the substrate W is cleaned while a reservoir L1 of cleaning liquid is formed on the first surface 2a of the substrate W. The reservoir L1 is located upstream of the cleaning surface of the first roll cleaning tool 8A in the direction of travel Dw1 of the first surface 2a of the substrate W.

[0058] Furthermore, in the first cleaning step, while the cleaning surface of the first roll cleaning tool 8B is brought into contact with the first surface 2a of the substrate W, the first roll cleaning tool 8B is rotated in a first rotational direction Db1 in the opposite direction to the direction of travel Dw2 of the first surface 2a of the substrate W, so that the cleaning surface of the first roll cleaning tool 8B moves. As a result, the substrate W is cleaned while a reservoir L2 of cleaning liquid is formed on the first surface 2a of the substrate W. The reservoir L2 is located upstream of the cleaning surface of the first roll cleaning tool 8B in the direction of travel Dw2 of the first surface 2a of the substrate W.

[0059] Figure 9 is a plan view showing the substrate cleaning apparatus 1 shown in Figure 8 performing the second cleaning process. After the first cleaning process, in the second cleaning process, the first roll cleaning tool 8A is rotated in the second rotation direction Da2, which is opposite to the first rotation direction Da1, and the substrate W is cleaned while the cleaning liquid is discharged from the first surface 2a of the substrate W. Furthermore, in the second cleaning process, the first roll cleaning tool 8B is rotated in the second rotation direction Db2, which is opposite to the first rotation direction Db1, and the substrate W is cleaned while the cleaning liquid is discharged from the first surface 2a of the substrate W.

[0060] In the embodiment shown in Figure 9, the substrate cleaning apparatus 1 includes two first roll cleaning tools 8A and 8B arranged parallel to the first surface 2a of the substrate W, but the number of first roll cleaning tools may be three or more. The arrangement and length of the multiple first roll cleaning tools are not particularly limited, as long as the entire first surface 2a of the substrate W can come into contact with at least one of the three or more first roll cleaning tools while the substrate W is moving around once.

[0061] The embodiments described with reference to Figures 8 and 9 can also be applied to a second roll cleaning tool 9 for cleaning the second surface 2b of the substrate W. Specifically, the substrate cleaning apparatus 1 may include two or more second roll cleaning tools arranged parallel to the second surface 2b of the substrate W.

[0062] In the embodiments described so far, the substrate W is cleaned in a horizontal position. In one embodiment, as shown in Figure 10, the substrate cleaning apparatus 1 may be configured to clean the substrate W in a vertical position. In this case, the substrate holding device 5 (not shown in Figure 10) is configured to hold the substrate W in a vertical position. In the embodiment shown in Figure 10, in the first cleaning step, the cleaning surface of the first roll cleaning tool 8 is brought into contact with the first surface 2a of the substrate W, and the first roll cleaning tool 8 is rotated in a first rotation direction D1 in the opposite direction to the direction of travel Dw of the first surface 2a of the substrate W, so that the substrate W is cleaned while forming a reservoir L of cleaning liquid on the first surface 2a of the substrate W. After the first cleaning step, in the second cleaning step, the first roll cleaning tool 8 is rotated in a second rotation direction D2 opposite to the first rotation direction D1, so that the substrate W is cleaned while discharging cleaning liquid from the first surface 2a of the substrate W.

[0063] In one embodiment, as shown in Figure 11, the substrate cleaning apparatus 1 may be configured to clean the substrate W in an oblique position. In this case, the substrate holding device 5 (not shown in Figure 11) is configured to hold the substrate W in an oblique position. In the embodiment shown in Figure 11, in the first cleaning step, the cleaning surface of the first roll cleaning tool 8 is brought into contact with the first surface 2a of the substrate W, and the first roll cleaning tool 8 is rotated in a first rotation direction D1 in the opposite direction to the direction of travel Dw of the first surface 2a of the substrate W, thereby cleaning the substrate W while forming a reservoir L of cleaning liquid on the first surface 2a of the substrate W. After the first cleaning step, in the second cleaning step, the first roll cleaning tool 8 is rotated in a second rotation direction D2 opposite to the first rotation direction D1, thereby cleaning the substrate W while discharging cleaning liquid from the first surface 2a of the substrate W.

[0064] The embodiments described above are intended to enable persons with ordinary skill in the art to implement the present invention. Various modifications of the above embodiments can be made naturally by those skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments as well. Therefore, the present invention is not limited to the embodiments described, but is to be interpreted in the broadest sense according to the technical idea defined by the claims.

[0065] The present invention can be used in a substrate cleaning method and a substrate cleaning apparatus for cleaning substrates such as wafers.

[0066] 1. Substrate cleaning device 2a. First surface 2b. Second surface 5. Substrate holding device 6. Holding rollers 8, 8A, 8B. First roll cleaning tool 9. Second roll cleaning tool 11, 11A, 11B. First cleaning liquid nozzle 12. Second cleaning liquid nozzle 15. First cleaning tool rotation mechanism 16. Second cleaning tool rotation mechanism 21. First support part 22. Second support part 25. First rotation shaft 26. Second rotation shaft 31. First cleaning tool pressing mechanism 32. Second cleaning tool pressing mechanism 35. Support shaft 36. Support arm 40. Operation control unit 40a. Storage device 40b. Arithmetic unit

Claims

1. A substrate cleaning method comprising: holding and rotating a substrate; supplying a cleaning solution to the surface of the substrate; and cleaning the substrate by pressing a roll cleaning tool, which extends radially to the substrate, against the surface of the substrate while rotating the roll cleaning tool, wherein the cleaning of the substrate includes: a first cleaning step of cleaning the substrate while bringing the cleaning surface of the roll cleaning tool into contact with the surface of the substrate, and rotating the roll cleaning tool in a first rotational direction in which the cleaning surface of the roll cleaning tool moves in the direction opposite to the direction of movement of the surface of the substrate, thereby forming a reservoir of the cleaning solution on the surface of the substrate; and a second cleaning step of cleaning the substrate after the first cleaning step, by rotating the roll cleaning tool in a second rotational direction opposite to the first rotational direction, thereby discharging the cleaning solution from the surface of the substrate.

2. The substrate cleaning method according to claim 1, wherein the second pressing force applied to the roll cleaning tool in the second cleaning step is smaller than the first pressing force applied to the roll cleaning tool in the first cleaning step.

3. The substrate cleaning method according to claim 1, wherein the cleaning solution is supplied to a region of the substrate surface located upstream of the cleaning surface of the roll cleaning tool in the direction of travel of the substrate surface.

4. The substrate cleaning method according to claim 1, wherein the rotation speed of the substrate in the second cleaning step is greater than the rotation speed of the substrate in the first cleaning step.

5. The substrate cleaning method according to claim 1, wherein the rotational speed of the roll cleaning tool in the second cleaning step is equal to or greater than the rotational speed of the roll cleaning tool in the first cleaning step.

6. The substrate cleaning method according to claim 1, wherein the axial length of the roll cleaning tool is equal to or greater than the radius of the substrate.

7. The apparatus comprises a substrate holding device for holding and rotating a substrate, a cleaning liquid nozzle for supplying cleaning liquid to the surface of the substrate, a roll cleaning tool extending radially from the substrate, a cleaning tool rotation mechanism for rotating the roll cleaning tool about its axis, a cleaning tool pressing mechanism for pressing the roll cleaning tool against the surface of the substrate, and an operation control unit for controlling the operation of the substrate holding device, the cleaning liquid nozzle, the cleaning tool rotation mechanism, and the cleaning tool pressing mechanism, wherein the operation control unit gives a command to the substrate holding device to rotate the substrate, gives a command to the cleaning liquid nozzle to supply cleaning liquid to the surface of the substrate, gives a command to the cleaning tool pressing mechanism to bring the cleaning surface of the roll cleaning tool into contact with the surface of the substrate, and gives a command to the cleaning tool rotation mechanism to rotate the roll cleaning tool in a first rotation direction, thereby performing a first cleaning step of cleaning the substrate while forming a reservoir of cleaning liquid on the surface of the substrate. A substrate cleaning apparatus is configured to perform a second cleaning step in which a cleaning tool rotation mechanism is given a command to rotate the roll cleaning tool in a second rotation direction opposite to the first rotation direction, thereby cleaning the substrate while discharging the cleaning liquid from the surface of the substrate, wherein the first rotation direction is the direction in which the cleaning surface of the roll cleaning tool moves in a direction opposite to the direction in which the surface of the substrate moves.

8. The substrate cleaning apparatus according to claim 7, wherein in the first cleaning step, the cleaning tool pressing mechanism is configured to apply a first pressing force to the roll cleaning tool, and in the second cleaning step, the cleaning tool pressing mechanism is configured to apply a second pressing force to the roll cleaning tool that is smaller than the first pressing force.

9. The substrate cleaning apparatus according to claim 7, wherein the cleaning liquid nozzle is arranged to supply the cleaning liquid to a region of the substrate surface located upstream of the cleaning surface of the roll cleaning tool in the direction of travel of the substrate surface.

10. The substrate cleaning apparatus according to claim 7, wherein the rotation speed of the substrate in the second cleaning step is greater than the rotation speed of the substrate in the first cleaning step.

11. The substrate cleaning apparatus according to claim 7, wherein the rotational speed of the roll cleaning tool in the second cleaning step is equal to or greater than the rotational speed of the roll cleaning tool in the first cleaning step.

12. The substrate cleaning apparatus according to claim 7, wherein the axial length of the roll cleaning tool is equal to or greater than the radius of the substrate.

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