Circuit board cleaning method

Abstract

The present invention provides a method for cleaning a substrate that can suppress the residue of metal on the substrate. [Solution] A method for cleaning a substrate to which metal has adhered, comprising: a holding step of holding the substrate with a holding table; and a cleaning step of supplying a fluid containing metal-adsorbing particles that adsorb the metal to the substrate, thereby adsorbing the metal adsorbed to the substrate by the metal-adsorbing particles.

Description

Technical Field

[0001] The present invention relates to a method for cleaning a substrate.

Background Art

[0002] A device chip used in an electric device such as a mobile phone or a PC (Personal Computer) is manufactured by subjecting a substrate (wafer) made of a semiconductor material such as silicon to various processes. Specifically, for example, a dicing line is set on the surface of the substrate, and devices such as ICs (Integrated Circuits) are formed in each of a plurality of regions separated by the dicing line.

[0003] Then, the substrate on which the devices are formed is ground from the back side by a grinding device or the like to be processed to a predetermined thickness, and then divided along the dicing line by a dividing device (a cutting device, a laser processing device, etc.). Thereby, a plurality of device chips each having a device are manufactured.

[0004] Before forming a device on the wafer, a process of flattening the device surface may be performed by polishing the surface (device surface) of the wafer on which the device is to be formed. For example, in a process of forming a power device on a single crystal SiC wafer, CMP (Chemical Mechanical Polishing) is performed in which the device surface of the single crystal SiC wafer is polished with a polishing pad while supplying a polishing liquid to the single crystal SiC wafer (see Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] During the manufacturing process of device chips, metallic foreign matter may adhere to the substrate. For example, when processing a substrate with a processing machine, if metallic particles adhere to the chuck table that holds the substrate or the transport unit that transports the substrate, that metallic material may unintentionally adhere to the substrate. Also, when processing a substrate with a processing machine, a processing fluid is supplied to the substrate for purposes such as cooling. However, metal components of the tank that stores the processing fluid, or metal components of the piping that delivers the processing fluid from the tank to the substrate, may become mixed into the processing fluid. These metals may be mixed into the processing fluid as metal fragments or metal ions and, when supplied to the substrate along with the processing fluid, may adhere to the substrate. Furthermore, in the polishing process where the substrate is polished, a polishing fluid is supplied to the substrate. At this time, metallic material derived from components contained in the polishing fluid may adhere to the substrate.

[0007] As described above, if metals or their oxides remain attached to the substrate, they can negatively affect the quality of the substrate. For example, on a single-crystal SiC wafer, crystalline thin films (epitaxial layers) that constitute semiconductor devices are formed by epitaxial growth. However, if the above-mentioned metals remain on the device surface of the single-crystal SiC wafer, epitaxial growth is inhibited, making it difficult to form a high-quality epitaxial layer. In addition, the remaining metals can contaminate the device, potentially leading to reduced reliability and malfunctions.

[0008] The object of the present invention is to provide a method for cleaning a substrate that can suppress the residue of metal on the substrate. [Means for solving the problem]

[0009] A method for cleaning a substrate according to one aspect of the present invention is a method for cleaning a substrate on which metal has adhered, comprising: a holding step of holding the substrate with a holding table; and a cleaning step of supplying a fluid containing metal-adsorbing particles that adsorb the metal to the substrate, thereby adsorbing the metal adsorbed to the substrate by the metal-adsorbing particles.

[0010] Preferably, the cleaning step further comprises a polishing step in which the substrate is polished while a polishing liquid containing the metal is supplied to the substrate, and in the cleaning step, the liquid is supplied to the substrate to which the metal contained in the polishing liquid is attached, thereby adsorbing the metal attached to the substrate with the metal adsorption particles.

[0011] A method for cleaning a substrate according to another aspect of the present invention is a method for cleaning a substrate on which metal is attached, comprising: a holding step of holding the substrate with a holding table; and a cleaning step of bringing a cleaning member containing metal-adsorbing particles that adsorb the metal onto the substrate into contact with the substrate, thereby adsorbing the metal attached to the substrate with the metal-adsorbing particles.

[0012] Preferably, the cleaning step further comprises a polishing step in which the substrate is polished while a polishing solution containing the metal is supplied to the substrate, and in the cleaning step, the metal adsorbed on the substrate is adsorbed by the metal adsorbing particles by bringing the cleaning member containing the metal adsorbing particles that adsorb the metal into contact with the substrate to which the metal contained in the polishing solution has adhered.

[0013] Preferably, the cleaning member is made of a resin that holds the metal adsorbent particles.

[0014] Preferably, in the cleaning step, the cleaning member is brought into contact with the substrate while a fluid is supplied to the substrate, and the fluid contains the metal adsorbent particles.

[0015] Preferably, the metal-adsorbing particles are silica particles having functional groups that adsorb the metal.

[0016] Preferably, the average particle size of the metal adsorbed particles is 25 μm or more and 150 μm or less. [Effects of the Invention]

[0017] A method for cleaning a substrate according to one aspect of the present invention supplies a fluid containing metal adsorbing particles that adsorb metal attached to the substrate to the substrate. Thereby, the metal attached to the substrate is adsorbed and captured by the metal adsorbing particles contained in the fluid and removed from the substrate. Thereby, the remaining metal on the substrate is suppressed.

[0018] Also, a method for cleaning a substrate according to another aspect of the present invention brings a cleaning member containing metal adsorbing particles that adsorb metal attached to the substrate into contact with the substrate. Thereby, the metal attached to the substrate is adsorbed and captured by the metal adsorbing particles contained in the cleaning member and removed from the substrate. Thereby, the remaining metal on the substrate is suppressed.

Brief Description of the Drawings

[0019] [Figure 1] It is a perspective view showing a processing apparatus. [Figure 2] FIG. 2(A) is a perspective view showing a grinding wheel for rough grinding, and FIG. 2(B) is a perspective view showing a grinding wheel for finish grinding. [Figure 3] It is a perspective view showing a polishing unit. [Figure 4] It is a side view showing a state in which a substrate is held by a chuck table of a processing apparatus. [Figure 5] It is a side view showing a state in which a substrate is being ground by a grinding unit of a processing apparatus. [Figure 6] It is a partially sectional side view showing a state in which a substrate is being polished by a polishing unit of a processing apparatus. [Figure 7] FIG. 7(A) is a side view showing a cleaning unit and a substrate of a processing apparatus, and FIG. 7(B) is a top view of a holding table, a substrate, and a cleaning member.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, an embodiment of one aspect of the present invention will be described with reference to the attached drawings. First, a processing apparatus to which the cleaning method of this embodiment is applied will be described. Figure 1 is a perspective view showing a processing apparatus (grinding and polishing apparatus) 2 capable of performing grinding and polishing on a substrate 11. In Figure 1, the X-axis direction (first horizontal direction, left-right direction) and the Y-axis direction (second horizontal direction, front-back direction) are perpendicular to each other. The Z-axis direction (up-down direction, height direction, vertical direction) is perpendicular to the X-axis direction and the Y-axis direction.

[0021] The processing apparatus 2 includes a base 4 that supports or accommodates each component of the processing apparatus 2. A rectangular opening 4a is provided on the upper side of the front end of the base 4. A transport unit 6 for transporting the substrate 11 is provided inside the opening 4a. For example, a transport robot equipped with a robot hand (end effector) capable of holding the substrate 11 is used as the transport unit 6.

[0022] Cassette support bases 8A and 8B are provided in front of the opening 4a. Box-shaped cassettes 10A and 10B are placed on the cassette support bases 8A and 8B, respectively. Cassettes 10A and 10B are containers capable of holding multiple substrates 11, which are the objects to be processed by the processing device 2. When processing the substrates 11 with the processing device 2, cassettes 10A and 10B containing multiple substrates 11 are set on the cassette support bases 8A and 8B.

[0023] The substrate 11 is a disc-shaped wafer made of a semiconductor material such as single-crystal SiC, and has a first surface 11a and a second surface 11b that are generally parallel to each other. However, there are no restrictions on the type, material, shape, size, structure, etc. of the substrate 11. For example, the substrate 11 may be a disc-shaped wafer made of a semiconductor other than SiC (Si, GaAs, InP, GaN, etc.), glass, ceramics, resin, metal, etc.

[0024] For example, the first surface 11a of the substrate 11 is ground and polished by the processing device 2. This thins the substrate 11 and flattens the first surface 11a of the substrate 11. Multiple devices such as ICs (Integrated Circuits), LSIs (Large Scale Integrations), LEDs (Light Emitting Diodes), and MEMS (Micro Electro Mechanical Systems) devices are then formed on the first surface 11a of the substrate 11. Subsequently, multiple device chips, each containing a device, are manufactured by dividing the substrate 11 using processing devices such as a cutting device or a laser processing device.

[0025] However, the processing device 2 can also process a substrate 11 on which devices have already been formed. For example, if multiple devices are formed on the first surface 11a of the substrate 11, the processing device 2 may perform grinding and polishing on the second surface 11b of the substrate 11.

[0026] An alignment mechanism (positioning mechanism) 12 for positioning the substrate 11 is provided diagonally behind the opening 4a. The alignment mechanism 12 includes a temporary placement table 14 on which the substrate 11 is temporarily placed. The alignment mechanism 12 also includes, for example, a plurality of pins that contact the outer edge of the substrate 11 and grip the substrate 11.

[0027] The circuit boards 11 housed in cassettes 10A and 10B are transported onto the temporary placement table 14 by the transport unit 6. The alignment mechanism 12 then holds the circuit boards 11 on the temporary placement table 14 and clamps them with multiple pins to position the circuit boards 11 in the predetermined location.

[0028] A gate-shaped support structure 16 is installed on the side of the base 4, straddling the alignment mechanism 12. A transport unit 18 for transporting the substrate 11 is mounted on the support structure 16. For example, the support structure 16 is provided with a ball screw type moving mechanism (not shown) that moves the transport unit 18 along the X-axis, Y-axis, and Z-axis, and the transport unit 18 is connected to the moving mechanism. The transport unit 18 also includes one or more suction pads (not shown) that suction and hold the upper surface of the substrate 11.

[0029] A rectangular opening 4b is provided behind the alignment mechanism 12. A disc-shaped turntable 20 is provided inside the opening 4b. A rotational drive source (not shown), such as a motor, is connected to the turntable 20 to rotate the turntable 20 around a rotation axis that is approximately parallel to the Z-axis direction.

[0030] Multiple chuck tables 22 for holding the substrate 11 are provided on the turntable 20. For example, four chuck tables 22 are arranged at roughly equal intervals (90° intervals) along the circumferential direction of the turntable 20.

[0031] The turntable 20 rotates clockwise (in the direction indicated by arrow R) and counterclockwise in a plan view. As a result, each chuck table 22 is sequentially positioned in the transport area A, grinding area B (first grinding area, rough grinding area), grinding area C (second grinding area, finish grinding area), and polishing area D, before returning to the transport area A.

[0032] The upper surface of the chuck table 22 constitutes a holding surface 22a for holding the substrate 11. The holding surface 22a is connected to a suction source (not shown), such as an ejector, via a flow path (not shown), a valve (not shown), etc., formed inside the chuck table 22. The chuck table 22 is also connected to a rotational drive source (not shown), such as a motor, which rotates the chuck table 22 around a rotation axis that is approximately parallel to the Z-axis direction.

[0033] The substrate 11, which has been aligned by the alignment mechanism 12, is transported by the transport unit 18 to the chuck table 22 positioned in the transport area A. Then, with the substrate 11 placed on the holding surface 22a of the chuck table 22, when the suction force (negative pressure) of the suction source is applied to the holding surface 22a, the substrate 11 is held in place by the chuck table 22.

[0034] At the rear end of the base 4 (behind the turntable 20 and chuck table 22), a rectangular parallelepiped-shaped support structure 24 is provided, protruding upward from the top surface of the base 4. The surface (front) of the support structure 24 is positioned approximately parallel to the XZ plane. On the surface side of the support structure 24, moving mechanisms 26A and 26B for moving the grinding units 38A and 38B, which will be described later, are provided.

[0035] Each of the moving mechanisms 26A and 26B is equipped with a pair of guide rails 28 arranged along the Z-axis direction on the surface side of the support structure 24. A flat moving plate 30 is slidably mounted on the pair of guide rails 28. A nut portion (not shown) is provided on the back side (rear side) of the moving plate 30. A ball screw 32, which is arranged along the Z-axis direction between the pair of guide rails 28, is screwed into this nut portion. A pulse motor 34 for rotating the ball screw 32 is connected to the end of the ball screw 32. When the ball screw 32 is rotated by the pulse motor 34, the moving plate 30 moves along the guide rails 28 in the Z-axis direction.

[0036] A support member 36 is fixed to the front surface (front side) of the movable plate 30. The support member 36 fixed to the movable plate 30 of the movable mechanism 26A supports the rough grinding unit 38A for rough grinding of the substrate 11. On the other hand, the support member 36 fixed to the movable plate 30 of the movable mechanism 26B supports the finish grinding unit 38B for finish grinding of the substrate 11. The grinding unit 38A is positioned above the grinding area B, and the grinding unit 38B is positioned above the grinding area C.

[0037] Each grinding unit 38A and 38B is equipped with a cylindrical housing 40. The housing 40 contains a cylindrical spindle 42 arranged along the Z-axis. The tip (lower end) of the spindle 42 is exposed from the housing 40, and a disc-shaped wheel mount 44 made of metal or the like is fixed to the tip of the spindle 42. A rotational drive source, such as a motor, is connected to the base (upper end) of the spindle 42 to rotate the spindle 42.

[0038] A grinding wheel 46A for rough grinding is mounted on the underside of the wheel mount 44 of the grinding unit 38A. On the other hand, a grinding wheel 46B for finish grinding is mounted on the underside of the wheel mount 44 of the grinding unit 38B.

[0039] Figure 2(A) is a perspective view showing a grinding wheel 46A mounted on a grinding unit 38A. As shown in Figure 2(A), the grinding wheel 46A comprises an annular wheel base 48A made of a metal such as an aluminum alloy, and a plurality of grinding wheels 50A fixed to the lower surface of the wheel base 48A. The grinding wheels 50A are formed by fixing abrasive grains made of diamond, cBN (cubic boron nitride), etc., with a binder (bonding material) such as a metal bond, resin bond, or vitrified bond. For example, a plurality of rectangular parallelepiped-shaped grinding wheels 50A are arranged in an annular shape along the outer edge of the wheel base at roughly equal intervals.

[0040] Figure 2(B) is a perspective view showing the grinding wheel 46B mounted on the grinding unit 38B. As shown in Figure 2(B), the grinding wheel 46B comprises an annular wheel base 48B and a plurality of grinding wheels 50B fixed to the lower surface of the wheel base 48B. The shape, material, configuration, and function of the wheel base 48B and the grinding wheels 50B are the same as those of the wheel base 48A and the grinding wheels 50A, respectively. However, the average particle size of the abrasive grains contained in the grinding wheels 50B is smaller than the average particle size of the abrasive grains contained in the grinding wheels 50A.

[0041] The grinding wheels 46A and 46B each rotate around a rotation axis that is approximately parallel to the Z-axis direction, power transmitted from the rotation drive source via the spindle 42 and wheel mount 44. As a result, the multiple grinding wheels 50A and 50B each rotate along an annular rotation path (rotation path) that is approximately parallel to the horizontal plane (XY plane).

[0042] The chuck table 22 holding the substrate 11 is placed in grinding area B (see Figure 1), and the grinding wheel 50A is brought into contact with the substrate 11 while the chuck table 22 and grinding wheel 46A are rotated, thereby performing rough grinding on the substrate 11. Subsequently, the chuck table 22 holding the substrate 11 is placed in grinding area C (see Figure 1), and the grinding wheel 50B is brought into contact with the substrate 11 while the chuck table 22 and grinding wheel 46B are rotated, thereby performing finish grinding on the substrate 11.

[0043] As shown in Figure 1, a polishing unit 52 for polishing the substrate 11 is provided in the polishing area D. After the grinding of the substrate 11 by the grinding units 38A and 38B is completed, the chuck table 22 holding the substrate 11 is positioned in the polishing area D, and the substrate 11 is polished by the polishing unit 52.

[0044] Figure 3 is a perspective view showing the polishing unit 52. The polishing unit 52 is supported by a rectangular parallelepiped support structure 54 provided in or near the polishing area D (see Figure 1). The surface of the support structure 54 is arranged approximately parallel to the XZ plane. An X-axis movement mechanism 56 is provided on the surface side of the support structure 54 to move the polishing unit 52 along the X-axis direction.

[0045] The X-axis movement mechanism 56 includes a pair of X-axis guide rails 58 arranged along the X-axis direction on the surface side of the support structure 54. A rectangular parallelepiped X-axis movement block 60 is mounted on the pair of X-axis guide rails 58 so as to be slidable along the X-axis guide rails 58.

[0046] A nut (not shown) is provided on the back side of the X-axis movement block 60. An X-axis ball screw (not shown), which is positioned along the X-axis direction between a pair of X-axis guide rails 58, is screwed into this nut. An X-axis pulse motor 62, which rotates the X-axis ball screw, is connected to the end of the X-axis ball screw. When the X-axis ball screw is rotated by the X-axis pulse motor 62, the X-axis movement block 60 moves along the X-axis guide rails 58 in the X-axis direction.

[0047] A Z-axis movement mechanism 64 is provided on the surface side of the X-axis movement block 60 to move the polishing unit 52 along the Z-axis direction. The Z-axis movement mechanism 64 includes a pair of Z-axis guide rails 66 arranged along the Z-axis direction on the surface side of the X-axis movement block 60. A rectangular parallelepiped Z-axis movement block 68 is mounted on the pair of Z-axis guide rails 66 so as to be slidable along the Z-axis guide rails 66.

[0048] A nut (not shown) is provided on the back side of the Z-axis movement block 68. A Z-axis ball screw (not shown), which is positioned along the Z-axis direction between a pair of Z-axis guide rails 66, is screwed into this nut. A Z-axis pulse motor 70, which rotates the Z-axis ball screw, is connected to the end of the Z-axis ball screw. When the Z-axis pulse motor 70 rotates the Z-axis ball screw, the Z-axis movement block 68 moves along the Z-axis guide rails 66 in the Z-axis direction.

[0049] A polishing unit 52 is mounted on the surface side of the Z-axis movement block 68. The polishing unit 52 comprises a cylindrical housing 72 fixed to the Z-axis movement block 68. The housing 72 houses a cylindrical spindle 74 arranged along the Z-axis direction. The tip (lower end) of the spindle 74 is exposed from the housing 72, and a disc-shaped mount 76 made of metal or the like is fixed to the tip of the spindle 74. A rotational drive source, such as a motor, for rotating the spindle 74 is connected to the base (upper end) of the spindle 74.

[0050] A polishing pad 78 used for polishing the circuit board 11 is attached to the underside of the mount 76. For example, the polishing pad 78 is detachably fixed to the mount 76 by fasteners such as bolts.

[0051] The polishing pad 78 comprises a disc-shaped base 80 and a polishing layer 82 fixed to the base 80 and in contact with the substrate 11 to polish the substrate 11. The base 80 is made of a metal such as an aluminum alloy and is formed to be approximately the same diameter as the mount 76. The polishing layer 82 is formed, for example, in the shape of a disc approximately the same diameter as the base 80 and is fixed to the lower surface of the base 80 with an adhesive or the like. However, multiple polishing layers 82 may be fixed to the lower surface of the base 80 in a state where they are separated from each other. The lower surface of the polishing layer 82 constitutes a polishing surface 82a that contacts the substrate 11 and polishes the substrate 11.

[0052] The polishing pad 78 rotates around a rotation axis that is approximately parallel to the Z-axis direction by power transmitted from a rotation drive source via a spindle 74 and a mount 76. The substrate 11 is polished by placing the chuck table 22 holding the substrate 11 in the polishing area D (see Figure 1) and rotating the chuck table 22 and the polishing pad 78 while bringing the polishing surface 82a of the polishing layer 82 into contact with the substrate 11.

[0053] As shown in Figure 1, a cleaning unit 84 for cleaning the substrate 11 is provided in front of the alignment mechanism 12. Once polishing of the substrate 11 is complete, the turntable 20 rotates, and the chuck table 22 holding the substrate 11 is placed back in the transport area A. The substrate 11 is then transported from the chuck table 22 to the cleaning unit 84 by the transport unit 18, and cleaned by the cleaning unit 84. This washes away processing debris, particles, and other foreign matter adhering to the substrate 11. After that, the substrate 11 is placed in cassette 10A or cassette 10B by the transport unit 6. Details of the configuration and function of the cleaning unit 84 and the method of cleaning the substrate 11 by the cleaning unit 84 will be described later (see Figures 7(A) and 7(B)).

[0054] The processing apparatus 2 includes a controller (control unit, control unit, control device) 90 that controls the processing apparatus 2. The controller 90 is connected to each component of the processing apparatus 2 (transport unit 6, alignment mechanism 12, transport unit 18, turntable 20, chuck table 22, moving mechanisms 26A, 26B, grinding units 38A, 38B, polishing unit 52, cleaning unit 84, etc.). The controller 90 controls the operation of the processing apparatus 2 by outputting control signals to each component of the processing apparatus 2.

[0055] For example, the controller 90 is composed of a computer and includes a processing unit that performs calculations and other processing necessary for the operation of the processing device 2, and a storage unit that stores various information (data, programs, etc.) used for the operation of the processing device 2. The processing unit includes a processor such as a CPU (Central Processing Unit). The storage unit includes memory such as ROM (Read Only Memory) and RAM (Random Access Memory).

[0056] Next, a method for processing a substrate and a method for cleaning a substrate, which are carried out using the processing apparatus 2 described above, will be explained. In the method for processing the substrate 11 according to this embodiment, the steps of holding the substrate 11 with a chuck table 22, grinding the substrate 11 with grinding wheels 46A and 46B, polishing the substrate 11 with a polishing pad 78, and cleaning the substrate 11 with a cleaning unit 84 are carried out in order.

[0057] In this embodiment, as an example, we will describe the case where the first surface 11a of the substrate 11 shown in Figure 1 is the surface to be processed (ground surface, polished surface) and subjected to grinding and polishing. When processing the first surface 11a of the substrate 11, a protective member may be fixed to the second surface 11b of the substrate 11. For example, a film-like protective sheet made of resin or the like is attached to the second surface 11b of the substrate 11 as a protective member. This protects the second surface 11b of the substrate 11. Then, a cassette 10A or cassette 10B containing multiple substrates 11 is placed on a cassette support base 8A or cassette support base 8B.

[0058] When the processing device 2 is in operation, first, the substrate 11 housed in cassette 10A or cassette 10B is transported to the alignment mechanism 12 by the transport unit 6. After the alignment mechanism 12 aligns the substrate 11, the substrate 11 is held by the transport unit 18 and transported to the chuck table 22 located in the transport area A.

[0059] Figure 4 is a side view showing the substrate 11 being held by the chuck table 22 of the processing apparatus 2. The substrate 11 is placed on the chuck table 22 with the first surface 11a (workpiece surface) exposed upwards and the second surface 11b facing the holding surface 22a. In this state, when the suction force of the suction source is applied to the holding surface 22a, the substrate 11 is held by suction at the chuck table 22.

[0060] Next, the turntable 20 (see Figure 1) rotates, and the chuck table 22 holding the substrate 11 is positioned in the grinding area B. This positions the substrate 11 below the grinding wheel 46A. Then, the grinding unit 38A grinds the substrate 11, performing rough grinding on the substrate 11.

[0061] Figure 5 is a side view showing the grinding of the substrate 11 by the grinding unit 38A of the processing apparatus 2. The chuck table 22 is positioned so that the center of the substrate 11 and the rotation path of the grinding wheel 50A overlap in the Z-axis direction. In this state, the chuck table 22 and the grinding wheel 46A are rotated, and the grinding wheel 46A is lowered by the moving mechanism 26A (see Figure 1), bringing the grinding wheel 50A into contact with the first surface 11a of the substrate 11. As a result, the first surface 11a of the substrate 11 is scraped off by the grinding wheel 50A, and rough grinding is performed on the substrate 11. When the substrate 11 is thinned to a predetermined thickness, the descent of the grinding wheel 46A is stopped, and the rough grinding of the substrate 11 is completed.

[0062] Next, the turntable 20 (see Figure 1) rotates, and the chuck table 22 holding the substrate 11 is positioned in the grinding area C. This positions the substrate 11 below the grinding wheel 46B. Then, the grinding unit 38B grinds the substrate 11, performing finish grinding on the substrate 11. The procedure for grinding the substrate 11 by the grinding unit 38B is the same as the procedure for grinding the substrate 11 by the grinding unit 38A (see Figure 5).

[0063] Specifically, the chuck table 22 is positioned so that the center of the substrate 11 and the rotation path of the grinding wheel 50B (see Figure 2(B)) overlap in the Z-axis direction. In this state, the chuck table 22 and the grinding wheel 46B are rotated, and the grinding wheel 46B is lowered by the moving mechanism 26B (see Figure 1), bringing the grinding wheel 50B into contact with the first surface 11a of the substrate 11. As a result, the first surface 11a of the substrate 11 is ground away by the grinding wheel 50B, and the substrate 11 is given a finish grind. When the substrate 11 is thinned to a predetermined thickness, the descent of the grinding wheel 46B is stopped, and the finish grinding of the substrate 11 is completed.

[0064] Furthermore, nozzles (not shown) for supplying liquid (grinding fluid) such as pure water are provided inside or near the grinding units 38A and 38B. During grinding of the substrate 11, grinding fluid is continuously supplied to the substrate 11 and the grinding wheels 50A and 50B. This cools the substrate 11 and the grinding wheels 50A and 50B, and washes away the debris (processing debris, grinding debris) generated by grinding the substrate 11.

[0065] As described above, the substrate 11 is subjected to rough grinding and finish grinding by grinding the substrate 11 with grinding wheels 46A and 46B. When the first surface 11a side of the substrate 11 is ground with grinding wheels 50A and 50B, arc-shaped grinding marks (saw marks) formed along the rotational path of the grinding wheels 50A and 50B may remain on the first surface 11a side of the substrate 11.

[0066] Next, the turntable 20 (see Figure 1) rotates, and the chuck table 22 holding the substrate 11 is positioned in the polishing area D. This positions the substrate 11 below the polishing pad 78. Then, the substrate 11 is polished by the polishing unit 52 (polishing step).

[0067] Figure 6 is a partial cross-sectional side view showing how the substrate 11 is polished by the polishing unit 52 of the processing apparatus. A polishing fluid supply passage 92 is provided in the center of the polishing unit 52, which is formed to penetrate the polishing unit 52 along the Z-axis direction.

[0068] Specifically, a channel 74a is provided in the center of the spindle 74, passing through the spindle 74 along the height direction (Z-axis direction). Similarly, a channel 76a is provided in the center of the mount 76, passing through the mount 76 along the thickness direction (Z-axis direction). Furthermore, a channel 78a is provided in the center of the polishing pad 78, passing through the polishing pad 78 along the thickness direction (Z-axis direction). The channels 74a, 76a, and 78a are connected to form a polishing fluid supply channel 92. The tip (lower end) of the polishing fluid supply channel 92 opens at the center of the polishing surface 82a. Meanwhile, a polishing fluid supply source 94 is connected to the base end (upper end) of the polishing fluid supply channel 92 to supply the polishing fluid.

[0069] When polishing the substrate 11, polishing liquid 96 is supplied from the polishing liquid supply source 94 to the polishing liquid supply passage 92. For example, the polishing liquid 96 corresponds to a liquid (chemical solution) used to chemically surface treat the substrate 11. The polishing liquid 96 supplied to the polishing liquid supply passage 92 flows inside the polishing layer 82 or flows out from the lower end of the polishing liquid supply passage 92. In this way, the polishing liquid 96 is supplied to the substrate 11 and the polishing layer 82.

[0070] When polishing the substrate 11, the positional relationship between the substrate 11 and the polishing pad 78 is first adjusted. Specifically, the position of the polishing pad 78 is adjusted by the X-axis movement mechanism 56 (see Figure 3) so that the entire first surface 11a (workpiece surface) of the substrate 11 is positioned inside the outer circumference of the polishing layer 82 of the polishing pad 78 in a plan view. This positions the polishing layer 82 so that it overlaps with the entire substrate 11.

[0071] Subsequently, while the chuck table 22 and polishing pad 78 are rotated, the polishing pad 78 is lowered by the Z-axis movement mechanism 64 (see Figure 3), bringing the substrate 11 and the polishing pad 78 closer together (processing feed). Polishing liquid 96 is also supplied from the polishing liquid supply source 94 to the substrate 11 and the polishing layer 82 via the polishing liquid supply passage 92. When the polishing surface 82a of the polishing layer 82 comes into contact with the first surface 11a of the substrate 11, wet polishing is performed on the first surface 11a of the substrate 11.

[0072] As described above, when the first surface 11a of the substrate 11 is polished, the first surface 11a is flattened. This improves the crystallinity of the first surface 11a of the substrate 11. In addition, if grinding marks are formed on the first surface 11a of the substrate 11 after the aforementioned grinding, the grinding marks are removed by polishing. Polishing is then continued until the substrate 11 reaches a predetermined thickness, after which the feed rate is stopped and the polishing of the substrate 11 is completed.

[0073] The material of the polishing solution 96 supplied to the substrate 11 and the polishing layer 82 is appropriately selected according to the material of the substrate 11, the purpose of polishing, processing conditions, etc. Examples of polishing solutions 96 include acidic solutions containing dissolved permanganate, and alkaline solutions containing dissolved sodium hydroxide or potassium hydroxide. The following describes an example where the polishing solution 96 is an acidic solution.

[0074] For example, as the polishing solution 96, an aqueous solution is used in which an oxidizing agent and a pH adjusting agent are dissolved in a solvent such as pure water. As the oxidizing agent, permanganates such as sodium permanganate and potassium permanganate can be used. As the pH adjusting agent, lanthanum nitrate and cerium nitrate can be used. By adjusting the polishing solution 96 to be strongly acidic (for example, pH value less than 3) with a pH adjusting agent, the oxidizing ability of the oxidizing agent (permanganate) is fully exerted. This makes it possible to improve the amount of polishing per unit time (polishing rate) of the substrate 11 by the polishing layer 82.

[0075] However, the pH adjusting agent can be appropriately selected depending on the material of the substrate 11, the material of the oxidizing agent, etc. For example, nitric acid-based water-soluble compounds (lanthanum nitrate, cerium nitrate, yttrium nitrate, zirconyl nitrate, etc.), hydrochloric acid-based water-soluble compounds (lanthanum chloride, cerium chloride, yttrium chloride, zirconyl chloride, etc.), sulfuric acid-based water-soluble compounds (lanthanum sulfate, cerium sulfate, yttrium sulfate, zirconyl sulfate, etc.) can be used as pH adjusting agents.

[0076] When polishing liquid 96 is supplied to the contact area between the substrate 11 and the polished surface 82a of the polishing layer 82, the polishing liquid 96 acts on the first surface 11a of the substrate 11, causing repeated formation and removal of the oxide layer on the first surface 11a of the substrate 11. As a result, CMP is applied to the first surface 11a of the substrate 11.

[0077] For example, if the substrate 11 is a single-crystal SiC wafer, a polishing solution 96 containing permanganate as an oxidizing agent can be used. When the polishing solution 96 is supplied to the substrate 11, Si atoms are oxidized by the oxidizing action of permanganate on the SiC crystal plane exposed on the first surface 11a of the substrate 11, forming a silicon oxide layer. This silicon oxide layer is brittle compared to the SiC crystal and is easily removed by contact with the polishing layer 82. As a result, a new SiC crystal plane is exposed on the first surface 11a of the substrate 11. Subsequently, the formation and removal of the silicon oxide layer is repeated in the same manner, thereby polishing the first surface 11a of the substrate 11.

[0078] Furthermore, the carbon atoms contained in the single-crystal SiC wafer are transformed into carboxyl groups, carbon dioxide, etc. The carboxyl groups are then transformed into metal ions (La) contained in the polishing solution 96. 3+ Ce 3+ It coordinates with abrasive particles contained in the polishing layer 82 and is extracted from the single-crystal SiC wafer. In addition, carbon dioxide dissolves in the polishing solution 96 as carbonate ions or is released from the polishing solution 96 as a gas.

[0079] Once the polishing of the substrate 11 described above is complete, the chuck table 22 is placed in the transport area A (see Figure 1) as previously stated. Then, the substrate 11 is transported from the chuck table 22 to the cleaning unit 84 by the transport unit 18, and the substrate 11 is cleaned by the cleaning unit 84.

[0080] Figure 7(A) is a side view showing the cleaning unit 84 and substrate 11 of the processing apparatus 2, and Figure 7(B) is a top view of the holding table 86, substrate 11 and cleaning member 100. As shown in Figure 7(A), the cleaning unit 84 includes a holding table (spinner table) 86 that holds and rotates the substrate 11, a nozzle 88 that supplies fluid to the substrate 11 held by the holding table 86, and a support member 102 that supports a cleaning member 100 that can contact the substrate 11 held by the holding table 86.

[0081] The upper surface of the holding table 86 constitutes a holding surface for holding the substrate 11. The holding surface is connected to a suction source (not shown), such as an ejector, via a flow path (not shown), a valve (not shown), etc., formed inside the holding table 86. The holding table 86 is also connected to a rotational drive source (not shown), such as a motor, which rotates the holding table 86 around a rotation axis that is roughly parallel to the Z-axis direction.

[0082] For example, the nozzle 88 is formed in a roughly L-shape and supplies fluid 13 from its tip. A moving mechanism 98 for moving the nozzle 88 is connected to the base end of the nozzle 88. For example, the moving mechanism 98 is composed of a rotational drive source such as a motor that rotates the nozzle 88 around a rotation axis that is roughly parallel to the Z-axis direction. By operating the moving mechanism 98, the tip of the nozzle 88 can be rotated and positioned in a position that overlaps with the holding table 86 (supply position) and a position that does not overlap with the holding table 86 (retracted position).

[0083] Furthermore, a fluid supply source (not shown) is connected to the nozzle 88 to supply cleaning fluid to the substrate 11 via piping and a pump, etc. For example, the fluid used may be a liquid such as pure water, a gas such as air, or a mixed fluid of a liquid such as pure water and a gas such as air.

[0084] The cleaning member 100 has, for example, a cylindrical shape, and is configured such that the diameter of the cleaning member 100 is smaller than the diameter of the substrate 11. The lower surface of the cleaning member 100 is a cleaning surface that contacts the substrate 11 and cleans it. For example, the cleaning member 100 is made of a resin such as melamine, polyurethane, or polyvinyl alcohol (PVA).

[0085] A support member 102 is connected to the cleaning member 100. For example, the support member 102 is formed in a roughly L-shape, and the cleaning member 100 is attached to the tip of the support member 102. A moving mechanism 104 for moving the cleaning member 100 and the support member 102 is connected to the base end of the support member 102. For example, the moving mechanism 104 includes a lifting mechanism such as an air cylinder or a linear actuator for moving (raising and lowering) the support member 102 along the Z-axis direction, and a rotational drive source such as a motor for rotating the support member 102 around a rotation axis that is roughly parallel to the Z-axis direction.

[0086] When the support member 102 is rotated by the moving mechanism 104, the cleaning member 100 pivots around the rotation axis of the support member 102 and moves back and forth along an arc-shaped trajectory 15. For example, the trajectory 15 of the cleaning member 100 is set to pass through a point that coincides with the center of the holding table 86 in the Z-axis direction. Furthermore, by raising and lowering the support member 102 with the moving mechanism 104, the cleaning member 100 can be positioned in a position where it contacts the substrate 11 (contact position) and a position where it does not contact (non-contact position).

[0087] The fluid and / or cleaning member 100 supplied from the nozzle 88 contains metal-adsorbing particles that adsorb metal. The metal-adsorbing particles adsorb and capture metal attached to the substrate 11, thereby suppressing the residue of metal on the substrate 11. Details of the metal attached to the substrate 11 and the metal-adsorbing particles will be described later.

[0088] When the substrate 11 is cleaned by the cleaning unit 84, a holding step is first performed in which the substrate 11 is held by the holding table 86. Specifically, the transport unit 18 places the substrate 11 on the holding table 86 so that the second surface 11b (the surface to be held) of the substrate 11 faces the holding surface (upper surface) of the holding table 86. Then, a suction source (not shown) is activated, and the negative pressure generated from the suction source is applied to the holding surface of the holding table 86 via a flow path (not shown) and a valve (not shown), etc. As a result, the substrate 11 is attracted to the holding surface and held by the holding table 86.

[0089] Next, a cleaning step is performed in which the substrate 11 is cleaned. First, the holding table 86 that holds the substrate 11 rotates. Also, the moving mechanism 98 moves the nozzle 88 and positions the tip of the nozzle 88 so that it overlaps with the substrate 11 (the supply position). Then, the fluid 13 is supplied to the substrate 11 from the tip of the nozzle 88 that is positioned at the supply position.

[0090] Next, the moving mechanism 104 rotates the cleaning member 100 and positions it so that it overlaps with the substrate 11. The moving mechanism 104 also lowers the cleaning member 100 so that its lower surface (cleaning surface) contacts the first surface 11a (surface to be cleaned) of the substrate 11. With the cleaning member 100 in contact with the substrate 11, the moving mechanism 104 rotates the cleaning member 100 alternately clockwise and counterclockwise in a plan view. As a result, the cleaning member 100 reciprocates along the trajectory 15 while in contact with the first surface 11a of the substrate 11. Consequently, the cleaning member 100 moves so as to trace the first surface 11a of the substrate 11 to which the fluid 13 has been supplied, and the cleaning member 100 rubs and cleans the first surface 11a of the substrate 11.

[0091] As described above, cleaning the substrate 11 with the cleaning unit 84 removes any foreign matter adhering to the substrate 11. In particular, if metallic foreign matter adheres to the substrate 11, it is likely to negatively affect the quality of the substrate 11, so it is preferable that any remaining metal on the substrate 11 is reliably removed by the cleaning unit 84.

[0092] Metal particles may adhere to the substrate 11 as foreign matter due to various factors. For example, if metal particles adhere to the chuck table 22 (see Figure 1) that holds the substrate 11 or to the transport units 6 and 18 (see Figure 1) that transport the substrate 11, metal may unintentionally adhere to the substrate 11 during holding or transport. In addition, during the grinding and polishing process (see Figures 5 and 6), metal components of the tank that supplies the grinding fluid and polishing fluid to the substrate 11, or metal components of the piping that sends the fluid from the tank to the grinding unit and polishing unit, may become mixed into the grinding fluid and polishing fluid. Metal (metal fragments or metal ions) mixed into the grinding fluid and polishing fluid are supplied to the substrate 11 along with the processing fluid and polishing fluid, and may adhere to the substrate 11.

[0093] Furthermore, metals derived from components in the polishing solution 96 (see Figure 6) may adhere to the substrate 11. For example, if the polishing solution 96 contains permanganate as an oxidizing agent, manganese may adhere to the first surface 11a of the substrate 11 during polishing. This manganese then oxidizes, and manganese oxides (MnO2, MnO3, etc.) may remain on the substrate 11 as metal particles after polishing.

[0094] As described above, residual metals and their oxides on the substrate 11 have an adverse effect on the quality of the substrate 11. For example, if the substrate 11 is a single-crystal SiC wafer, a crystalline thin film (epitaxial layer) that constitutes a semiconductor device may be formed on the single-crystal SiC wafer by epitaxial growth. However, if metals remain on the single-crystal SiC wafer, epitaxial growth is inhibited, making it difficult to form a high-quality epitaxial layer. In addition, residual metals may contaminate the device, potentially leading to a decrease in device reliability or malfunction.

[0095] Therefore, in this embodiment, when the substrate 11 is cleaned by the cleaning unit 84, the fluid 13 supplied to the substrate 11 and / or the cleaning member 100 that comes into contact with the substrate 11 are made to contain metal adsorbent particles capable of adsorbing and capturing metal adhering to the substrate 11. Specifically, the fluid 13 supplied from the nozzle 88 contains a predetermined amount of metal adsorbent particles. The cleaning member 100 is made of a resin or the like that holds the metal adsorbent particles. As a result, metal adhering to the substrate 11 can be adsorbed, captured, and removed from the substrate 11.

[0096] Metal-adsorbing particles are particles capable of adsorbing a specific metal (metal scavengers). For example, metal-adsorbing particles are silica particles equipped with functional groups that adsorb a specific metal. The average particle size of metal-adsorbing particles is, for example, between 25 μm and 150 μm (typically 30 μm, 60 μm, 100 μm, etc.). The above average particle size value of metal-adsorbing particles corresponds to the particle size at 50% of the integrated particle size distribution measured by, for example, laser diffraction / scattering (median diameter, d50, 50% diameter). An example of commercially available silica particles that can be used as metal-adsorbing particles is SCAVENGER / metal removal silica (SH SILICA, SO3H SILICA, Diamine SILICA, NH SILICA, etc.) manufactured by Fuji Silicia Chemical Co., Ltd.

[0097] For example, if the polishing solution 96 (see Figure 6) used when polishing the substrate 11 contains permanganate, the permanganate dissociates in the polishing solution 96 to become permanganate ions, which adhere to the first surface 11a side of the substrate 11. In this case, silica particles having sulfo groups that can adsorb manganese are included in the fluid 13 and the cleaning member 100 as metal adsorption particles. Manganese ions react with the metal adsorption particles contained in the fluid 13 supplied to the substrate 11 and the metal adsorption particles contained in the cleaning member 100. Specifically, manganese ions are adsorbed onto the metal adsorption particles by bonding with the sulfo groups of the metal adsorption particles. As a result, manganese is removed from the first surface 11a side of the substrate 11, making it less likely for metal (manganese oxide) to remain on the substrate 11 after polishing.

[0098] However, the material, particle size, and quantity of the metal adsorption particles can be appropriately selected according to the material and quantity of the metal to be adsorbed. Furthermore, the fluid 13 and the cleaning member 100 may contain two or more types of metal adsorption particles made of different materials.

[0099] Furthermore, the amount of metal adsorbent particles contained in the fluid 13 and the cleaning member 100 is appropriately set so that the metal removal effect is sufficiently exerted. For example, the content of metal adsorbent particles in the fluid 13 is set to 0.1 vol% or more and 50 vol% or less, preferably 10 vol% or more and 20 vol% or less. This content corresponds to the ratio of the total volume of metal adsorbent particles (the sum of the volumes of multiple metal adsorbent particles) to the volume of the fluid 13 (a liquid such as pure water, a gas such as air, or a mixed fluid in which a liquid such as pure water and a gas such as air are mixed).

[0100] Furthermore, the content of metal adsorbent particles in the cleaning member 100 is set to 0.1 vol% or more and 50 vol% or less, preferably 10 vol% or more and 30 vol% or less. It is preferable that the metal adsorbent particles are contained within the above content range in at least the area including the surface of the cleaning member 100 that comes into contact with the substrate 11 (for example, the area within 1 mm from the surface (cleaning surface) of the cleaning member 100).

[0101] The metal adsorbing particles contained in the fluid 13 and / or cleaning member 100 remove the metal adsorbing from the substrate 11. Specifically, when the fluid 13 is supplied to the first surface 11a side of the substrate 11, the metal adsorbing particles contained in the fluid 13 approach or come into contact with the first surface 11a side of the substrate 11. Also, when the cleaning member 100 comes into contact with the first surface 11a side of the substrate 11, the metal adsorbing particles contained in the cleaning member 100 approach or come into contact with the first surface 11a side of the substrate 11. At this time, the metal adsorbing from the first surface 11a side of the substrate 11 is adsorbed by the metal adsorbing particles.

[0102] For example, as mentioned above, when polishing the substrate 11 (see Figure 6), if a polishing solution 96 containing metal is supplied to the substrate 11, the metal contained in the polishing solution may adhere to and remain on the substrate 11. In this case, by supplying fluid 13 to the substrate 11 with the cleaning unit 84 and bringing the cleaning member 100 into contact with it, the metal that has adhered to the substrate 11 during polishing can be adsorbed and removed by metal adsorption particles.

[0103] As described above, in this embodiment, a fluid containing metal-adsorbing particles that adsorb metal attached to the substrate 11 is supplied to the substrate 11. As a result, metal attached to the substrate 11 during polishing or other processes is adsorbed and captured by the metal-adsorbing particles and removed from the substrate 11. Consequently, residual metal on the substrate 11 is suppressed.

[0104] Furthermore, in this embodiment, a cleaning member 100 containing metal-adsorbing particles that adsorb metal attached to the substrate 11 is brought into contact with the substrate 11. As a result, metal attached to the substrate 11 during polishing or other processes is adsorbed and captured by the metal-adsorbing particles and removed from the substrate 11. Consequently, the remaining metal on the substrate 11 is suppressed.

[0105] In this embodiment, metal-adsorbing particles are contained in both the fluid 13 supplied to the substrate 11 and the cleaning member 100, but metal-adsorbing particles may be contained in only one of the fluid 13 or the cleaning member 100.

[0106] Furthermore, in this embodiment, a configuration in which the cleaning unit 84 includes both a nozzle 88 and a cleaning member 100 has been described. However, the cleaning unit 84 may include only one of either the nozzle 88 or the cleaning member 100.

[0107] If the cleaning unit 84 is equipped with a nozzle 88, the cleaning step involves rotating the holding table 86 that holds the substrate 11 while supplying a fluid 13 containing metal adsorption particles from the nozzle 88 to the center of the substrate 11. As a result, the fluid 13 supplied to the substrate 11 flows from the center of the substrate 11 toward the outer edge due to centrifugal force, washing away foreign matter adhering to the substrate 11. At this time, the metal adsorption particles contained in the fluid 13 adsorb and remove metal adhering to the substrate 11.

[0108] If the cleaning unit 84 is equipped with a cleaning member 100, in the cleaning step, the holding table 86 that holds the substrate 11 is rotated while the cleaning member 100 containing metal adsorption particles is brought into contact with the substrate 11 and rotated. As a result, foreign matter adhering to the substrate 11 is removed by the cleaning member 100, and metal adhering to the substrate 11 is adsorbed by the metal adsorption particles. When cleaning the substrate 11 with the cleaning member 100, a cleaning solution (such as pure water) that does not contain metal adsorption particles may be supplied to the substrate 11 to promote the removal of foreign matter.

[0109] Furthermore, although this embodiment describes a case in which the substrate 11 is cleaned by a cleaning unit 84 provided in the processing apparatus 2, the substrate 11 may also be cleaned by a cleaning apparatus that has the same configuration as the cleaning unit 84 described above but is independent of the processing apparatus 2.

[0110] Furthermore, the structures, methods, etc., according to the above embodiments can be modified as appropriate without departing from the scope of the objectives of the present invention. [Explanation of Symbols]

[0111] 11 circuit boards 11a 1st page 11b Side 2 13 Fluid 15 Trajectory 2. Processing equipment (grinding and polishing equipment) 4 bases 4a,4b opening 6. Transport Unit 8A, 8B Cassette Support Stand 10A, 10B Cassette 12. Alignment mechanism (positioning mechanism) 14 Temporary Placement Table 16 Support structure 18 Conveyor Unit 20 Turntables 22 Chuck Table 22a Holding surface 24 Support structure 26A,26B Moving mechanism 28 Guide rails 30 Mobile Plates 32 Ball screw 34 pulse motor 36 Support Member 38A, 38B Grinding Unit 40 Housing 42 spindles 44 Wheel Mount 46A, 46B Grinding Wheels 48A, 48B Wheel base 50A, 50B grinding wheels 52 Polishing Units 54 Support structure 56 X-axis movement mechanism 58 X-axis guide rail 60 X-axis movement block 62 X-axis pulse motor 64 Z-axis movement mechanism 66 Z-axis guide rails 68 Z-axis movement block 70 Z-axis pulse motor 72 Housing 74 spindles 74a Flow channel 76 Mount 76a Flow channel 78 polishing pads 78a Channel 80 base 82 Polishing layer 82a Polished surface 84 Washing Unit 86. Holding table (spinner table) 88 nozzles 90 Controller (control unit, control unit, control device) 92 Polishing liquid supply path 94 Polishing fluid supply source 96 Polishing liquid 98 Moving mechanism 100 Cleaning component 102 Support member 104 Moving mechanism

Claims

1. A method for cleaning a substrate that has metal attached to it, A holding step in which the substrate is held by a holding table, A method for cleaning a substrate, comprising: a cleaning step of supplying a fluid containing metal-adsorbing particles that adsorb the metal to the substrate, thereby adsorbing the metal adhering to the substrate with the metal-adsorbing particles.

2. Prior to the cleaning step, the polishing step further comprises polishing the substrate while supplying it with a polishing solution containing the metal, The method for cleaning a substrate according to claim 1, wherein in the cleaning step, the fluid is supplied to the substrate to which the metal contained in the polishing liquid is attached, thereby adsorbing the metal attached to the substrate with the metal adsorption particles.

3. A method for cleaning a substrate that has metal attached to it, A holding step in which the substrate is held by a holding table, A method for cleaning a substrate, comprising: a cleaning step of bringing a cleaning member containing metal-adsorbing particles that adsorb the metal into contact with the substrate, thereby adsorbing the metal adsorbing onto the substrate with the metal-adsorbing particles.

4. Prior to the cleaning step, the polishing step further comprises polishing the substrate while supplying it with a polishing solution containing the metal, The method for cleaning a substrate according to claim 3, wherein in the cleaning step, the cleaning member is brought into contact with the substrate to which the metal contained in the polishing liquid is attached, thereby adsorbing the metal attached to the substrate with the metal adsorption particles.

5. The method for cleaning a substrate according to claim 3, wherein the cleaning member is made of a resin that holds the metal adsorbent particles.

6. In the cleaning step, the cleaning member is brought into contact with the substrate while supplying fluid to the substrate. The method for cleaning a substrate according to claim 3, wherein the fluid contains the metal adsorbent particles.

7. The method for cleaning a substrate according to any one of claims 1 to 6, wherein the metal-adsorbing particles are silica particles having a functional group that adsorbs the metal.

8. The method for cleaning a substrate according to any one of claims 1 to 6, wherein the average particle size of the metal adsorbed particles is 25 μm or more and 150 μm or less.

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