Substrate processing device and substrate processing method

Abstract

The present invention relates to a substrate processing device and a substrate processing method which are for polishing a substrate, e.g., a wafer. The substrate processing device includes: a polishing part (4) for polishing a peripheral portion of a substrate (W); a residual-film detection part (9) for detecting a residual film on the peripheral portion of the substrate (W) which has been polished by the polishing part (4); and a control unit (20) which assesses whether repolishing of the peripheral portion of the substrate (W) is necessary or not, on the basis of the results of the residual-film detection by the residual-film detection part (9), and which, when having assessed that repolishing is necessary, determines polishing conditions for the repolishing on the basis of the results of the residual-film detection. The polishing part (4) is configured so as to repolish the peripheral portion of the substrate (W) under the determined polishing conditions.

Description

Substrate processing apparatus and substrate processing method

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

[0002] In recent years, managing the surface condition of substrates has attracted attention from the perspective of improving yield in semiconductor device manufacturing. During the semiconductor device manufacturing process, various materials are deposited on silicon wafers. As a result, unwanted films and surface roughness form around the edges of the substrate. In recent years, a method of transporting a substrate by holding only the edges with an arm has become common. Under these circumstances, the unwanted films remaining on the edges peel off during various processes and adhere to devices formed on the substrate, reducing yield. Therefore, to remove the unwanted films from the edges of the substrate, the edges of the substrate are polished using a polishing device.

[0003] JP 2013-160687 A JP 2008-537316 A

[0004] However, the state of the unwanted film formed on the peripheral edge of the substrate varies from substrate to substrate. Therefore, if the peripheral edge is polished according to a fixed polishing recipe regardless of the state of the film, the unwanted film may not be completely removed from the peripheral edge of the substrate. If the unwanted film cannot be removed by polishing and a remaining film remains, the peripheral edge of the substrate must be polished again.

[0005] Therefore, the present invention provides a substrate processing apparatus and a substrate processing method that can appropriately determine the polishing conditions for regrinding based on the state of the remaining film on the peripheral edge of the substrate.

[0006] In one aspect, a substrate processing apparatus is provided, comprising: a polishing unit that polishes a peripheral portion of a substrate; a residual film detection unit that detects a residual film on the peripheral portion of the substrate polished by the polishing unit; and a control unit that determines whether or not re-polishing of the peripheral portion of the substrate is necessary based on the detection result of the residual film by the residual film detection unit, and when it is determined that re-polishing is necessary, determines polishing conditions for the re-polishing based on the detection result of the residual film, wherein the polishing unit is configured to re-polish the peripheral portion of the substrate under the determined polishing conditions. In one aspect, the residual film detection unit comprises an imaging device that generates an image of the peripheral portion of the substrate, and a detection processing unit that detects the residual film on the peripheral portion of the substrate based on the image. In one aspect, the residual film detection unit further comprises a substrate holding device that holds and rotates the substrate, and the image is an image of the entire peripheral portion of the substrate.

[0007] In one aspect, the detection processing unit is configured to calculate the area of ​​the remaining film from the hue appearing on the image, and the control unit is configured to determine whether or not the regrinding of the peripheral portion of the substrate is necessary based on a remaining film ratio, which is the ratio of the area of ​​the remaining film within the target area to the total area of ​​the target area in the image. In one aspect, the control unit is configured to determine a polishing time as the polishing condition based on the remaining film ratio and correlation data between the remaining film ratio and polishing time.

[0008] In one aspect, the residual film detection unit is configured to detect the residual film in each of a plurality of regions of the peripheral edge lined up in the thickness direction of the substrate, and the control unit is configured to determine whether re-polishing is necessary in each of the plurality of regions based on the detection result of the residual film and to determine, as the polishing conditions for the re-polishing, a polishing angle corresponding to the region determined to require re-polishing, the plurality of regions being regions to be polished at different polishing angles by the polishing unit. In one aspect, the residual film detection unit includes a plurality of imaging devices that generate images of the plurality of regions, respectively, and a detection processing unit that detects the residual film in each of the plurality of regions based on the images of the plurality of regions. In one aspect, the residual film detection unit includes an imaging device that generates an image of the peripheral edge of the substrate and a detection processing unit that detects the residual film in the peripheral edge of the substrate based on the image, and the control unit has a polishing condition determination model constructed by machine learning, and is configured to input the image into the polishing condition determination model and output the polishing conditions for the re-polishing from the polishing condition determination model.

[0009] In one aspect, a substrate processing method is provided that includes detecting a residual film on a peripheral edge of a substrate polished by a polishing unit, determining whether or not re-polishing of the peripheral edge of the substrate is necessary based on the detection result of the residual film, and when it is determined that re-polishing is necessary, determining polishing conditions for the re-polishing based on the detection result of the residual film, and re-polishing the peripheral edge of the substrate by the polishing unit under the determined polishing conditions. In one aspect, detecting the residual film on the peripheral edge of the substrate includes generating an image of the peripheral edge of the substrate by an imaging device, and detecting the residual film on the peripheral edge of the substrate based on the image. In one aspect, generating the image of the peripheral edge of the substrate includes generating an image of the entire circumference of the peripheral edge of the substrate while rotating the substrate by a substrate holding device.

[0010] In one aspect, detecting the residual film on the peripheral edge of the substrate involves calculating the area of ​​the residual film from the hue appearing on the image, and determining whether or not the peripheral edge of the substrate needs to be re-polished involves determining whether or not the peripheral edge of the substrate needs to be re-polished based on a residual film rate, which is the ratio of the area of ​​the residual film within the target area to the total area of ​​the target area in the image. In one aspect, determining the polishing conditions for re-polishing involves determining a polishing time as the polishing condition based on the residual film rate and correlation data between the residual film rate and polishing time.

[0011] In one aspect, detecting the residual film on the peripheral edge of the substrate involves detecting the residual film in each of a plurality of regions on the peripheral edge that are aligned in the thickness direction of the substrate, determining whether or not regrinding is required on the peripheral edge of the substrate involves determining whether or not regrinding is required on each of the plurality of regions based on the detection result of the residual film, and determining the polishing conditions for the regrinding includes determining, as the polishing conditions for the regrinding, a polishing angle corresponding to the region determined to require regrinding, the plurality of regions being polished at different polishing angles by the polishing unit. In one aspect, detecting the residual film on the peripheral edge of the substrate involves generating an image of the peripheral edge of the substrate using an imaging device and detecting the residual film on the peripheral edge of the substrate based on the image, and determining the polishing conditions for the regrinding involves inputting the image into a polishing condition determination model constructed by machine learning and outputting the polishing conditions for the regrinding from the polishing condition determination model.

[0012] The control unit determines whether re-polishing is necessary based on the detection result of the remaining film on the peripheral edge of the substrate, and when it determines that re-polishing is necessary, determines the polishing conditions for re-polishing based on the detection result of the remaining film on the peripheral edge of the substrate. Therefore, it is possible to determine the polishing conditions for re-polishing that are suitable for the state of the remaining film on the peripheral edge of the substrate.

[0013] 1 is a plan view showing an embodiment of a substrate processing apparatus. FIG. 2A is an enlarged cross-sectional view showing a peripheral portion of a substrate. FIG. 2B is an enlarged cross-sectional view showing the peripheral portion of a substrate. FIG. 3 is a plan view showing an embodiment of a polishing module. FIG. 4 is a side view of the polishing module shown in FIG. 3. FIG. 5 is a view showing a state in which a polishing head is polishing a bevel portion of a substrate. FIG. 6 is a view showing a state in which a polishing head is polishing a top edge portion of a substrate. FIG. 7 is a view showing a state in which a polishing head is polishing a bottom edge portion of a substrate. FIG. 8 is a schematic view showing an embodiment of a residual film detection unit. FIG. 9 is an enlarged schematic view of the imaging device shown in FIG. 10. FIG. 11 is a view showing an example of images of multiple regions of the peripheral portion of a substrate, each generated by the imaging device. FIG. 12 is a view showing an example of an image of the entire circumference of the peripheral portion of a substrate. FIG. 13 is a flowchart showing an embodiment of a substrate processing method. FIG. 14 is a schematic view showing an embodiment of a control unit having a polishing condition determination model, and a residual film detection unit. FIG. 15 is a schematic view showing an example of a polishing condition determination model constructed using a deep learning method.

[0014] Embodiments of the present invention will now be described with reference to the drawings. Fig. 1 is a plan view showing one embodiment of a substrate processing apparatus. The substrate processing apparatus includes a housing 1, a load port 2, a polishing unit 4 having two polishing modules 4A and 4B, a cleaning unit 6, a drying unit 7, a residual film detection unit 9, a first temporary stage 11, a second temporary stage 12, a first transfer robot 14, a second transfer robot 15, a third transfer robot 16, a fourth transfer robot 17, and a control unit 20. The polishing modules 4A and 4B, the cleaning unit 6, the drying unit 7, the residual film detection unit 9, the first temporary stage 11, the second temporary stage 12, the first transfer robot 14, the second transfer robot 15, the third transfer robot 16, the fourth transfer robot 17, and the control unit 20 are disposed within the housing 1.

[0015] Substrates to be polished, such as wafers, are stored in a substrate cassette 19, and the substrate cassette 19 is placed on the load port 2. The first transport robot 14 is disposed adjacent to the load port 2. The first transport robot 14 removes the substrate to be polished from the substrate cassette 19 on the load port 2 and places it on the first temporary stage 11. The first temporary stage 11 is a temporary stage on which the substrate is temporarily placed before being polished by the polishing modules 4A and 4B.

[0016] The polishing unit 4, which includes two polishing modules 4A and 4B, is configured to polish the peripheral portion of a substrate such as a wafer. In this embodiment, the polishing unit 4 includes two polishing modules 4A and 4B, but in one embodiment, the polishing unit 4 may include one polishing module or three or more polishing modules. In this embodiment, the peripheral portion of the substrate is polished by at least one of the polishing module 4A and the polishing module 4B.

[0017] The second transport robot 15 is disposed adjacent to the polishing module 4A and the polishing module 4B. The second transport robot 15 transports a substrate placed on the first temporary table 11 to the polishing module 4A or the polishing module 4B. Furthermore, the second transport robot 15 removes the substrate from the polishing module 4A or the polishing module 4B and places it on the second temporary table 12. The second temporary table 12 is a temporary table on which the substrate polished by the polishing module 4A or the polishing module 4B is temporarily placed before being cleaned by the cleaning unit 6.

[0018] The third transfer robot 16 is disposed adjacent to the cleaning unit 6. The third transfer robot 16 transports the substrate placed on the second temporary stage 12 to the cleaning unit 6. The cleaning unit 6 of the present embodiment is configured to clean the substrate with a roll-shaped sponge member. In one embodiment, the cleaning unit 6 may be configured to clean the substrate with a pencil-shaped sponge member. In another embodiment, the substrate processing apparatus may include a cleaning unit that cleans the substrate with a pencil-shaped sponge member, in addition to the cleaning unit 6 that cleans the substrate with a roll-shaped sponge member.

[0019] The fourth transport robot 17 is disposed between the cleaning unit 6 and the drying unit 7. The fourth transport robot 17 removes the substrate from the cleaning unit 6 and transports it to the drying unit 7. The drying unit 7 is configured to dry the substrate that has been cleaned by the cleaning unit 6. The first transport robot 14 transports the substrate between the drying unit 7 and the residual film detection unit 9. The substrate that has been dried by the drying unit 7 is transported to the residual film detection unit 9 by the first transport robot 14.

[0020] The residual film detection unit 9 is configured to detect a residual film on the peripheral edge of a substrate that has been polished by the polishing module 4A and / or the polishing module 4B, cleaned by the cleaning unit 5, and dried by the drying unit 7. As will be described in detail below, the control unit 20 is configured to determine whether or not the peripheral edge of the substrate needs to be re-polished based on the detection result of the residual film by the residual film detection unit 9.

[0021] If the control unit 20 determines that the peripheral edge of the substrate needs to be re-polished, the first transport robot 14 removes the substrate from the remaining film detection unit 9 and transports the substrate to polishing module 4A or polishing module 4B. Polishing module 4A or polishing module 4B re-polishes the peripheral edge of the substrate. If the control unit 20 determines that the peripheral edge of the substrate does not need to be re-polished, the first transport robot 14 removes the substrate from the remaining film detection unit 9 and returns it to the substrate cassette 19 on the load port 2.

[0022] The polishing unit 4 (including polishing module 4A and polishing module 4B), cleaning unit 6, drying unit 7, residual film detection unit 9, first transport robot 14, second transport robot 15, third transport robot 16, and fourth transport robot 17 are electrically connected to the control unit 20. The operations of the polishing unit 4, cleaning unit 6, drying unit 7, residual film detection unit 9, first transport robot 14, second transport robot 15, third transport robot 16, and fourth transport robot 17 are controlled by the control unit 20.

[0023] The control unit 20 includes at least one computer. The control unit 20 includes a storage device 20a in which programs and the like are stored, and an arithmetic unit 20b that executes calculations according to instructions included in the programs. The storage device 20a includes a main storage device such as a random access memory (RAM) and an auxiliary storage device such as a hard disk drive (HDD) or a solid state drive (SSD). Examples of the arithmetic unit 20b include a CPU (central processing unit) and a GPU (graphics processing unit). However, the specific configuration of the control unit 20 is not limited to these examples.

[0024] Next, details of the polishing modules 4A and 4B of the polishing unit 4 will be described. The polishing modules 4A and 4B are configured to polish the peripheral portion of the substrate W. Figures 2A and 2B are enlarged cross-sectional views showing the peripheral portion of the substrate W. More specifically, Figure 2A is a cross-sectional view of a so-called straight-type substrate, and Figure 2B is a cross-sectional view of a so-called round-type substrate. The bevel portion B has a chamfered or rounded shape.

[0025] In the substrate W of FIG. 2A , the bevel portion B is the outermost peripheral surface of the substrate W, which is composed of an upper inclined surface (upper bevel portion) B1, a lower inclined surface (lower bevel portion) B2, and a side portion (apex) B3. In the substrate W of FIG. 2B , the bevel portion B is a portion having a curved cross section that constitutes the outermost peripheral surface of the substrate W. The top edge portion E1 is an annular flat portion located radially inward of the bevel portion B. The bottom edge portion E2 is located opposite the top edge portion E1 and is an annular flat portion located radially inward of the bevel portion B. The top edge portion E1 may also include a region in which a device is formed. In this specification, the peripheral portion of the substrate W refers to a region including at least one of the top edge portion E1, the bevel portion B, and the bottom edge portion E2.

[0026] FIG. 3 is a plan view showing one embodiment of the polishing module 4A, and FIG. 4 is a side view of the polishing module 4A shown in FIG. Polishing module 4A and polishing module 4B have basically the same configuration, so the following description will focus on polishing module 4A. Polishing module 4A includes a substrate holder 25, four polishing heads 30A-30D, four polishing tape supply mechanisms 40A-40D, a lower supply nozzle 51, and an upper supply nozzle 52. Polishing heads 30B and 30C are not shown in FIG. 4.

[0027] The substrate holder 25 includes a holding stage 27 that holds the substrate W by vacuum suction, a shaft 28 connected to the center of the holding stage 27, and a holding stage drive mechanism 29 that rotates and moves the holding stage 27 up and down. The shaft 28 of the substrate holder 25 extends through a base plate 68, and the holding stage drive mechanism 29 is disposed below the base plate 68. The holding stage drive mechanism 29 is configured to rotate the holding stage 27 about a rotation axis Cr and move it up and down along the rotation axis Cr. The axis passing through the center O1 of the substrate W coincides with the rotation axis Cr of the holding stage 27.

[0028] The polishing module 4A includes at least one polishing head for polishing the peripheral edge of the substrate W. In this embodiment, as shown in FIG. 3 , four polishing heads 30A, 30B, 30C, and 30D are arranged radially outward of the substrate W held by the substrate holder 25. In this embodiment, four polishing tape supply mechanisms 40A, 40B, 40C, and 40D are provided radially outward of the four polishing heads 30A, 30B, 30C, and 30D, respectively. In one embodiment, the number of polishing heads and the corresponding polishing tape supply mechanisms may be three or less, or five or more.

[0029] 3, the polishing head 30A and the polishing head 30D are arranged symmetrically with respect to a line Lc that passes through the center O1 of the substrate W and is perpendicular to the rotation axis Cr. The polishing head 10B and the polishing head 10C are arranged symmetrically with respect to the line Lc. However, the arrangement of the first polishing head 10A, the second polishing head 10B, the third polishing head 10C, and the fourth polishing head 10D is not limited to this embodiment.

[0030] The polishing head 30A is configured to press the polishing tape 22A supplied from the polishing tape supply mechanism 40A against the peripheral edge of the substrate W to polish the peripheral edge of the substrate W. The polishing head 30B is configured to press the polishing tape 22B supplied from the polishing tape supply mechanism 40B against the peripheral edge of the substrate W to polish the peripheral edge of the substrate W. The polishing head 30C is configured to press the polishing tape 22C supplied from the polishing tape supply mechanism 40C against the peripheral edge of the substrate W to polish the peripheral edge of the substrate W. The polishing head 30D is configured to press the polishing tape 22D supplied from the polishing tape supply mechanism 40D against the peripheral edge of the substrate W to polish the peripheral edge of the substrate W.

[0031] The polishing heads 30A, 30B, 30C, and 30D have basically the same configuration, and the polishing tape supply mechanisms 40A, 40B, 40C, and 40D also have basically the same configuration. The polishing head 30A and the polishing tape supply mechanism 40A will be described below.

[0032] 4, the polishing head 30A includes a pressing member 32 that presses the polishing surface of the polishing tape 22A against the peripheral edge of the substrate W, and an air cylinder 35 that serves as an actuator that moves the pressing member 32 toward the peripheral edge of the substrate W. The pressure of the polishing tape 22A against the substrate W is adjusted by controlling the air pressure supplied to the air cylinder 35. The pressing member 32 is disposed on the back side of the polishing tape 22A (the side opposite to the polishing surface having abrasive grains). When the pressing member 32 is moved toward the substrate W by the air cylinder 35, the pressing member 32 presses the back side of the polishing tape 22A against the peripheral edge of the substrate W. In this way, the polishing head 30A polishes the peripheral edge of the substrate W with the polishing tape 22A.

[0033] The polishing tape supply mechanism 40A is configured to supply the polishing tape 22A to the polishing head 30A and collect it from the polishing head 30A. The polishing tape supply mechanism 40A includes a tape supply reel 41, a tape take-up reel 42, and a plurality of guide rollers 44, 45, 46, and 47. The tape supply reel 41, the tape take-up reel 42, and the plurality of guide rollers 44, 45, 46, and 47 are fixed to a reel base 48. The polishing tape 22A is supplied to the polishing head 30A so that the polishing surface of the polishing tape 22A faces the peripheral edge of the substrate W. The traveling direction of the polishing tape 22A is guided by the guide rollers 44, 45, 46, and 47. The polishing tape 22A supplied to the polishing head 30A is fed at a predetermined speed by a tape feed mechanism 36 provided in the polishing head 30A.

[0034] Tension motors (not shown) are connected to the tape supply reel 41 and the tape take-up reel 42. The tape supply reel 41 and the tape take-up reel 42 are fixed to a reel base 48 via the tension motors. Each tension motor is configured to apply a predetermined torque to the tape supply reel 41 and the tape take-up reel 42, thereby applying a predetermined tension to the polishing tape 22A.

[0035] The lower supply nozzle 51 is configured to supply liquid to the lower surface of the substrate W. The upper supply nozzle 52 is configured to supply liquid to the upper surface of the substrate W. An example of the liquid supplied to the substrate W from the lower supply nozzle 51 and the upper supply nozzle 52 is pure water. During polishing of the substrate W, the liquid is supplied to the lower surface of the substrate W from the lower supply nozzle 51, and the liquid is supplied to the upper surface of the substrate W from the upper supply nozzle 52.

[0036] The polishing module 4A further includes four polishing head translation mechanisms 60 that translate the polishing heads 30A, 30B, 30C, and 30D in the radial direction of the substrate W. Each of the polishing head translation mechanisms 60 includes a connecting member 63, a guide rail 64, a connecting shaft 66, and an air cylinder 67 as an actuator. Since the four polishing head translation mechanisms 60 basically have the same configuration, only the polishing head translation mechanism 60 that translates the polishing head 30A will be described below.

[0037] The polishing head translation mechanism 60 is connected to the polishing head 30A via a movable plate 61. More specifically, the polishing head support member 38 connected to the polishing head 30A is fixed to the upper surface of the movable plate 61, and the polishing head translation mechanism 60 is connected to the lower surface of the movable plate 61. The polishing head 30A can move integrally with the movable plate 61.

[0038] The guide rails 64 extend in the radial direction of the holding stage 27 and are fixed to the upper surface of a base plate 68. The air cylinder 67 is connected to the movable plate 61 via a connecting member 63 and a connecting shaft 66 and is fixed to the upper surface of the base plate 68. The polishing head translation mechanism 60 drives the air cylinder 67 to move the movable plate 61 along the guide rails 64, thereby moving the polishing head 30A at a predetermined moving speed in a direction toward and away from the rotation axis Cr of the substrate W (i.e., the center O1 of the substrate W).

[0039] Furthermore, the specific configuration of the polishing head translation mechanism 60 is not limited to this embodiment, as long as the polishing head 30A can be moved in a direction toward the rotation axis Cr of the substrate W (i.e., the center O1 of the substrate W) and in a direction away from the rotation axis Cr (i.e., the center O1 of the substrate W).

[0040] 3, the polishing module 4A further includes four polishing head tilting mechanisms 70A, 70B, 70C, and 70D that tilt the polishing heads 30A, 30B, 30C, and 30D, respectively, relative to the substrate holding surface of the holding stage 27. The polishing head tilting mechanism 70A is connected to the polishing head 30A, the polishing head tilting mechanism 70B is connected to the polishing head 30B, the polishing head tilting mechanism 70C is connected to the polishing head 30C, and the polishing head tilting mechanism 70D is connected to the polishing head 30D. Since the four polishing head tilting mechanisms 70A to 70D basically have the same configuration, only the polishing head tilting mechanism 70A will be described below.

[0041] The polishing head tilting mechanism 70A includes a crank arm 72 connected to the polishing head 30A and an arm rotation device 73 that rotates the crank arm 72. One end of the crank arm 72 is located at the same height as the substrate holding surface of the holding stage 27 and is connected to the arm rotation device 73. The other end of the crank arm 72 is connected to the polishing head 30A. The arm rotation device 73 is disposed inside the polishing head support member 38.

[0042] When the arm rotation device 73 rotates the crank arm 72, the polishing head tilting mechanism 70A can tilt the entire polishing head 30A at a predetermined tilting speed relative to the substrate W on the substrate holding surface of the holding stage 27. Furthermore, the polishing head tilting mechanism 70A is configured to maintain the polishing head 30A at a predetermined tilt angle. Note that the specific configuration of the polishing head tilting mechanism 70A is not limited to that of this embodiment, as long as it can tilt the polishing head 30A relative to the substrate holding surface of the holding stage 27 and the substrate W.

[0043] 5 is a diagram showing the polishing head 30A polishing the bevel portion B of the substrate W. As shown in FIG. 5, the polishing head 30A can polish the bevel portion B of the substrate W while continuously changing the tilt angle of the polishing head 30A using the polishing head tilting mechanism 70A (see FIG. 3). Alternatively, while the tilt angle of the polishing head 30A is fixed by the polishing head tilting mechanism 70A, the polishing head 30A can polish specific regions of the bevel portion B of the substrate W (e.g., the upper inclined surface (upper bevel portion) B1, the lower inclined surface (lower bevel portion) B2, and the side portion (apex) B3 described with reference to FIG. 2A). For example, the polishing head 30A can be tilted by the polishing head tilting mechanism 70A to a polishing angle corresponding to the upper inclined surface (upper bevel portion) B1, and the polishing head 30A can polish the upper inclined surface (upper bevel portion) B1.

[0044] Similarly, the polishing heads 30B, 30C, and 30D can polish the bevel portion B of the substrate W while the polishing head tilting mechanisms 70B, 70C, and 70D continuously change the tilt angles of the polishing heads 30B, 30C, and 30D, respectively, or while the polishing head tilting mechanisms 70B, 70C, and 70D fix the tilt angles of the polishing heads 30B, 30C, and 30D, respectively.

[0045] Fig. 6 is a diagram showing the polishing head 30A polishing the top edge portion E1 of the substrate W, and Fig. 7 is a diagram showing the polishing head 30A polishing the bottom edge portion E2 of the substrate W. As shown in Fig. 6, the polishing head tilting mechanism 70A (see Fig. 3) tilts the pressing member 32 of the polishing head 30A so that it faces the top edge portion E1 of the substrate W, allowing the polishing head 30A to polish the top edge portion E1 of the substrate W. Furthermore, as shown in Fig. 7, the polishing head tilting mechanism 70A (see Fig. 3) tilts the pressing member 32 of the polishing head 30A so that it faces the bottom edge portion E2 of the substrate W, allowing the polishing head 30A to polish the bottom edge portion E2 of the substrate W.

[0046] Similarly, the polishing head tilting mechanisms 70B, 70C, and 70D tilt the polishing heads 30B, 30C, and 30D so that they face the top edge E1 and bottom edge E2 of the substrate W, respectively, so that the polishing heads 30B, 30C, and 30D can polish the top edge E1 and bottom edge E2 of the substrate W. In this manner, the polishing heads 30A to 30D can polish multiple regions of the peripheral edge of the substrate W (i.e., the bevel portion B, the top edge E1, and the bottom edge E2).

[0047] The polishing heads 30A to 30D can simultaneously polish the peripheral edge of the substrate W. For example, to improve the polishing rate, the polishing head 30A may polish the entire peripheral edge of the substrate W, including the top edge E1, bevel B, and bottom edge E2, and simultaneously the polishing head 30B may polish the entire peripheral edge of the substrate W, including the top edge E1, bevel B2, and bottom edge E2. Alternatively, the polishing head 30A may polish the top edge E1, the polishing head 30B may polish the bevel B, and the polishing head 30C may polish the bottom edge E2.

[0048] The polishing tapes 22A to 22D may be different types of polishing tapes. For example, the polishing tape 22A may be a polishing tape for rough polishing (i.e., a polishing tape with larger abrasive grains), and the polishing tapes 22B to 22D may be polishing tapes for finish polishing (i.e., a polishing tape with smaller abrasive grains). In this case, the polishing head 30A can roughly polish the entire peripheral edge of the substrate W, including the top edge portion E1, the bevel portion B, and the bottom edge portion E2, and then the polishing head 30B can polish the entire peripheral edge of the substrate W, including the top edge portion E1, the polishing head 30C can polish the bevel portion B, and the polishing head 30D can polish the entire peripheral edge of the substrate W, including the bottom edge portion E2.

[0049] The substrate holding unit 25, polishing heads 30A to 30D, polishing tape supply mechanisms 40A to 40D, lower supply nozzle 51, upper supply nozzle 52, polishing head translation mechanism 60, and polishing head tilting mechanisms 70A to 70D are electrically connected to the control unit 20 (see FIG. 1). The operations of the substrate holding unit 25, polishing heads 30A to 30D, polishing tape supply mechanisms 40A to 40D, lower supply nozzle 51, upper supply nozzle 52, polishing head translation mechanism 60, and polishing head tilting mechanisms 70A to 70D are controlled by the control unit 20.

[0050] The peripheral edge of the substrate W is polished as follows. The following describes the case where the peripheral edge of the substrate W is polished by the polishing head 30A of the polishing module 4A. When the substrate W is transported to the polishing module 4A, the control unit 20 issues a command to the holding stage driving mechanism 29 of the substrate holding unit 25 to raise the holding stage 27. The substrate W is placed on the substrate holding surface of the holding stage 27 and is held on the holding stage 27 by vacuum suction. The control unit 20 issues a command to the holding stage driving mechanism 29 of the substrate holding unit 25 to lower the substrate W to the polishing position and rotate the holding stage 27 and the substrate W. Furthermore, the control unit 20 issues a command to the lower supply nozzle 51 and the upper supply nozzle 52 to supply liquid from the lower supply nozzle 51 and the upper supply nozzle 52.

[0051] Next, the control unit 20 issues a command to the polishing tape supply mechanism 40A to start supplying the polishing tape 22A to the polishing head 30A. When polishing the top edge E1 of the substrate W, the control unit 20 issues a command to the polishing head tilting mechanism 70A to tilt the polishing head 30A to a polishing angle corresponding to the top edge E1. Thereafter, the control unit 20 issues a command to the polishing head translation mechanism 60 to move the polishing head 30A. The control unit 20 issues a command to the air cylinder 35 of the polishing head 30A to cause the pressing member 32 of the polishing head 30A to press the polishing tape 22A against the top edge E1 of the substrate W, thereby polishing the top edge E1. The same process is performed when polishing the bottom edge E2 of the substrate W.

[0052] When the bevel portion B of the substrate W is to be continuously polished, the control unit 20 issues a command to the polishing head tilting mechanism 70A to tilt the polishing head 30A to a polishing angle corresponding to the portion where polishing of the bevel portion B begins. Thereafter, the control unit 20 issues a command to the air cylinder 35 of the polishing head 30A to tilt the polishing head 30A within a predetermined angle range while the pressing member 32 of the polishing head 30A presses the polishing tape 22A against the peripheral edge portion of the substrate W.

[0053] When polishing a specific region (e.g., upper bevel portion B1) of the bevel portion B of the substrate W, the control unit 20 issues a command to the polishing head tilting mechanism 70A to tilt the polishing head 30A to a polishing angle corresponding to the specific region (e.g., upper bevel portion B1) of the bevel portion B. Thereafter, the control unit 20 issues a command to the air cylinder 35 of the polishing head 30A to press the polishing tape 22A against the specific region of the substrate W with the pressing member 32 of the polishing head 30A.

[0054] After the peripheral edge of the substrate W has been polished in accordance with the predetermined polishing recipe, the control unit 20 issues a command to each component of the polishing module 4A to terminate polishing of the substrate W. Specifically, the control unit 20 stops the operation of the polishing head translation mechanism 60 or the polishing head tilting mechanism 70A, stops driving the air cylinder 35 of the polishing head 30A, and moves the pressing member 32 of the polishing head 30A away from the substrate W. Thereafter, the control unit 20 stops the operation of the substrate holder 25, the polishing tape supply mechanism 40A, the polishing tape supply mechanism 40B, the lower supply nozzle 51, and the upper supply nozzle 52, thereby completing polishing of the substrate W.

[0055] Next, the details of the residual film detection unit 9 will be described. FIG. 8 is a schematic diagram showing one embodiment of the residual film detection unit 9. When polishing the peripheral edge of the substrate W by the polishing modules 4A and 4B, an unnecessary film may not be removed, leaving a residual film on the peripheral edge of the substrate W. The residual film detection unit 9 is configured to detect a residual film on the peripheral edge of the substrate W polished by the polishing modules 4A and 4B. As shown in FIG. 8 , the residual film detection unit 9 of this embodiment includes a substrate holding device 80 that holds and rotates the substrate W, at least one imaging device (in this embodiment, five imaging devices 86A, 86B, 86C, 86D, and 86E) that generates an image of the peripheral edge of the substrate W, and a detection processing unit 87 that detects a residual film on the peripheral edge of the substrate W based on the images generated by the imaging devices 86A to 86E.

[0056] The substrate holding device 80 includes a holding stage 82 that holds the substrate W by vacuum suction, a shaft 83 connected to the center of the holding stage 82, and a holding stage rotation mechanism 84 that rotates the holding stage 82. The holding stage rotation mechanism 84 is configured to rotate the holding stage 82 around the axis of the shaft 83.

[0057] 9 is an enlarged schematic diagram of the imaging devices 86A to 86E shown in FIG. 8. The five imaging devices 86A to 86E are configured to generate images of multiple (five, in this embodiment) regions of the peripheral edge of the substrate W that are aligned in the thickness direction of the substrate W. In this embodiment, the substrate W is the straight-type substrate described with reference to FIG. 2A, and the multiple regions of the peripheral edge of the substrate W are a top edge portion E1, an upper inclined surface (upper bevel portion) B1, a side portion (apex) B3, a lower inclined surface (lower bevel portion) B2, and a bottom edge portion E2. The multiple regions of the peripheral edge of the substrate W are polished at different polishing angles by the polishing modules 4A and 4B of the polishing unit 4.

[0058] The imaging device 86A is disposed facing the top edge portion E1 of the substrate W and is configured to generate an image including the top edge portion E1 of the substrate W. The imaging device 86B is disposed facing the upper inclined surface (upper bevel portion) B1 of the substrate W and is configured to generate an image including the upper inclined surface (upper bevel portion) B1 of the substrate W. The imaging device 86C is disposed facing the side portion (apex) B3 of the substrate W and is configured to generate an image including the side portion (apex) B3 of the substrate W. The imaging device 86D is disposed facing the lower inclined surface (lower bevel portion) B2 of the substrate W and is configured to generate an image including the lower inclined surface (lower bevel portion) B2 of the substrate W. The imaging device 86E is disposed facing the bottom edge portion E2 of the substrate W and is configured to generate an image including the bottom edge portion E2 of the substrate W.

[0059] Examples of the imaging devices 86A to 86E include cameras equipped with image sensors such as CCD sensors, CMOS sensors, etc. In the present embodiment, the imaging devices 86A to 86E are configured to generate color images of the peripheral edge of the substrate W. In one embodiment, the imaging devices 86A to 86E may be configured to generate grayscale images of the peripheral edge of the substrate W.

[0060] In this embodiment, the residual film detection unit 9 includes five imaging devices 86A to 86E, but the number of imaging devices is not particularly limited to this embodiment. For example, the residual film detection unit 9 may be configured to include a single imaging device and generate an image of part or the entire area of ​​the peripheral edge of the substrate W using the single imaging device.

[0061] In this embodiment, the substrate holding device 80 and the imaging devices 86A to 86E are electrically connected to the detection processing unit 87, and the operations of the substrate holding device 80 and the imaging devices 86A to 86E are controlled by the detection processing unit 87. In one embodiment, the substrate holding device 80 and the imaging devices 86A to 86E are electrically connected to the control unit 20, and the operations of the substrate holding device 80 and the imaging devices 86A to 86E may be controlled by the control unit 20.

[0062] The detection processing unit 87 includes at least one computer. The detection processing unit 87 includes a storage device 87a in which programs and the like are stored, and an arithmetic unit 87b that executes calculations according to instructions included in the programs. The storage device 87a includes a main storage device such as a random access memory (RAM) and an auxiliary storage device such as a hard disk drive (HDD) or a solid state drive (SSD). Examples of the arithmetic unit 87b include a CPU (central processing unit) and a GPU (graphics processing unit). However, the specific configuration of the detection processing unit 87 is not limited to these examples. In one embodiment, the detection processing unit 87 may be configured integrally with the control unit 20.

[0063] The detection processing unit 87 issues a command to the holding stage rotation mechanism 84 of the substrate holding device 80 to rotate the holding stage 82 and the substrate W, while causing the imaging devices 86A to 86E to generate images of the peripheral portion of the substrate W each time the substrate W rotates a predetermined angle. The detection processing unit 87 acquires images of the entire circumference of the peripheral portion of the substrate W generated by the imaging devices 86A to 86E during one rotation of the substrate W. The images of the entire circumference of the peripheral portion of the substrate W are multiple images of the peripheral portion of the substrate W lined up in the circumferential direction of the substrate W. For example, the detection processing unit 87 issues a command to the imaging devices 86A to 86E to generate images of the peripheral portion of the substrate W each time the substrate W rotates by 1.5°. Each of the imaging devices 86A to 86E generates 240 images (360° ÷ 1.5° = 240 images), which are images of the entire circumference of the corresponding region of the peripheral portion of the substrate W lined up in the circumferential direction of the substrate W, during one rotation of the substrate W.

[0064] 10 is a diagram showing examples of images Pa, Pb, Pc, Pd, and Pe of multiple regions of the peripheral edge of a substrate W, generated by the imaging devices 86A, 86B, 86C, 86D, and 86E, respectively. Images Pa to Pe shown in FIG. 10 are images generated by a single imaging session by the imaging devices 86A to 86E, respectively. Image Pa is an image including the top edge portion E1 of the substrate W, generated by the imaging device 86A. Image Pb is an image including the upper inclined surface (upper bevel portion) B1 of the substrate W, generated by the imaging device 86B. Image Pc is an image including the side portion (apex) B3 of the substrate W, generated by the imaging device 86C. Image Pd is an image including the lower inclined surface (lower bevel portion) B2 of the substrate W, generated by the imaging device 86D. Image Pe is an image including the bottom edge portion E2 of the substrate W, generated by the imaging device 86E.

[0065] Portions of the substrate W with different inclinations appear in different hues in the images. In the images shown in Figure 10, for example, image Pa includes a top edge portion E1 and a portion of an upper inclined surface (upper bevel portion) B1, and appears in a different hue from the top edge portion E1 and the upper inclined surface (upper bevel portion) B1. Image Pe includes a bottom edge portion E2 and a portion of a lower inclined surface (lower bevel portion) B2, and appears in a different hue from the lower inclined surface (lower bevel portion) B2 and the bottom edge portion E2.

[0066] Furthermore, the areas S from which unnecessary film has been removed by the polishing modules 4A and 4B (i.e., areas where no residual film exists) appear in different hues on the image than the areas R where residual film exists. In the example shown in Figure 10, residual film exists in the areas R indicated by hatching in the images Pa, Pb, and Pe.

[0067] The detection processing unit 87 sets target areas Ta, Tb, Tc, Td, and Te in the images Pa, Pb, Pc, Pd, and Pe, respectively. In the example shown in Fig. 10, the target areas Ta to Te are ranges surrounded by thick lines. The target areas Ta to Te are set in advance so as to exclude from the corresponding images portions other than the substrate W and portions that overlap among multiple images (for example, the upper bevel portion B1 of image Pa and the lower bevel portion B2 of image Pe). The set ranges of the target areas Ta to Te are stored in advance in the storage device 87a of the detection processing unit 87.

[0068] By appropriately setting a target region in each image, multiple images generated by multiple imaging devices can be made to correspond to different regions of the peripheral edge of the substrate W. In the example shown in Figure 10, target region Ta corresponds to the top edge E1 of the substrate W, target region Tb corresponds to the upper bevel B1 of the substrate W, target region Tc corresponds to the side (apex) B3 of the substrate W, target region Td corresponds to the lower bevel B2 of the substrate W, and target region Te corresponds to the bottom edge E2 of the substrate W. Therefore, the detection processing unit 87 can detect residual films in each of multiple regions of the peripheral edge of the substrate W, namely the top edge E1, the upper bevel B1, the side (apex) B3, the lower bevel B2, and the bottom edge E2, from the hues appearing in each of the target regions Ta to Te.

[0069] 11 is a diagram showing an example of an image of the entire circumference of the peripheral edge of the substrate W. Below, an image of the entire circumference of the top edge E1 of the substrate W generated by the imaging device 86A will be described as an example of an image of the entire circumference of the peripheral edge of the substrate W, but the same applies to images of the entire circumference of other regions of the peripheral edge of the substrate W generated by the imaging devices 86B to 86E.

[0070] 11 , the images of the entire circumference of the top edge portion E1 of the substrate W are Z images lined up in the circumferential direction of the substrate W. Images Pa-1 to Pa-Z constitute images of the entire circumference of the top edge portion E1 of the substrate W generated by the imaging device 86A. More specifically, image Pa-1 shown in FIG. 11 is the first image of the top edge portion E1 of the substrate W generated by the imaging device 86A, image Pa-2 is the second image of the top edge portion E1 of the substrate W generated by the imaging device 86A, image Pa-3 is the third image of the top edge portion E1 of the substrate W generated by the imaging device 86A, and image Pa-Z is the Zth image of the top edge portion E1 of the substrate W generated by the imaging device 86A. In one embodiment, the detection processing unit 87 may combine these images to generate a single image.

[0071] The detection processing unit 87 is configured to detect residual film R from the hue appearing in a target region in an image of the peripheral edge of the substrate W. In the example shown in FIG. 11 , the detection processing unit 87 detects residual film R from the hue appearing in target region Ta in images Pa-1 to Pa-Z. Specifically, the detection processing unit 87 acquires hue values ​​indicating the hue of each of the multiple pixels constituting each image. The detection processing unit 87 detects residual film R by comparing the hue values ​​of each of the multiple pixels constituting each image with a predetermined hue reference value. For example, when the hue value of a pixel is greater than the hue reference value, the detection processing unit 87 detects residual film R in that pixel. The hue reference value is predetermined based on experimental results or the like and is stored in the storage device 87a of the detection processing unit 87.

[0072] In this embodiment, the detection processing unit 87 is configured to calculate the area of ​​the residual film R within the target area from the hue that appears in the target area within the image of the peripheral edge of the substrate W. The area can be expressed as the number of pixels. In the example shown in Figure 11, the detection processing unit 87 calculates the numbers of pixels N1 to NZ, which are the areas of the residual film R that exist (area) within the target area Ta within the images Pa-1 to Pa-Z.

[0073] In one embodiment, the detection processing unit 87 may be configured to determine the thickness of the residual film R in the target region from the hue that appears in the target region in an image of the peripheral edge of the substrate W. The hue on the image varies depending on the thickness of the residual film R. The detection processing unit 87 may determine the thickness of the residual film R in the target region from the hue that appears in the target region based on correlation data between the hue on the image and the thickness of the residual film R that has been acquired in advance. In this case, the correlation data between the hue on the image and the thickness of the residual film R is acquired in advance based on experimental results or the like, and stored in the storage device 87a of the detection processing unit 87.

[0074] Furthermore, the detection processing unit 87 may determine the thickness of the residual film R for each pixel constituting the image. The detection processing unit 87 may determine the thickness of the residual film R for each pixel in a target region in the image, and calculate the average value of the thickness of the residual film R present in the target region.

[0075] In another embodiment, the residual film detection unit 9 may be a film thickness measurement device (e.g., an optical film thickness measurement device) that measures the thickness of a residual film present on the peripheral edge of the substrate W. In this case, the residual film detection unit 9 directly measures the thickness of the residual film present on the peripheral edge of the substrate W, without generating an image of the peripheral edge of the substrate W using an imaging device, to detect the residual film present on the peripheral edge of the substrate W.

[0076] The residual film detection unit 9 of this embodiment is configured to detect a residual film at each of the top edge E1, upper bevel B1, side (apex) B3, lower bevel B2, and bottom edge E2 of the peripheral edge of the substrate W, which are aligned in the thickness direction of the substrate W. Therefore, the detection result of the residual film by the residual film detection unit 9 includes the detection result of the residual film at each of the top edge E1, upper bevel B1, side B3, lower bevel B2, and bottom edge E2 of the peripheral edge of the substrate W.

[0077] The residual film detection unit 9 (specifically, the detection processing unit 87) is electrically connected to the control unit 20. The detection results of the residual film on the peripheral edge of the substrate W by the residual film detection unit 9 (specifically, the detection processing unit 87) are sent to the control unit 20. In the example shown in Fig. 11, the numbers of pixels N1 to NZ of the residual film R in the target region Ta in the images Pa-1 to Pa-Z are sent to the control unit 20 as the detection results of the residual film R on the top edge E1 of the substrate W.

[0078] The control unit 20 is configured to determine whether or not regrinding of the peripheral edge of the substrate W is necessary based on the detection result of the residual film R by the residual film detection unit 9. In this embodiment, the control unit 20 determines whether or not regrinding of each of the top edge E1, upper bevel B1, side (apex) B3, lower bevel B2, and bottom edge E2 of the peripheral edge of the substrate W is necessary based on the detection result of the residual film R by the residual film detection unit 9.

[0079] In this embodiment, the control unit 20 is configured to determine whether or not regrinding of the peripheral portion of the substrate W is necessary based on a remaining film ratio, which is the ratio of the area of ​​the remaining film R in the target region to the total area of ​​the target region in each image. For example, the control unit 20 determines whether or not regrinding is necessary based on the remaining film ratio, which is the ratio of the number of pixels where the remaining film R exists to the total number of pixels in the target region in each image.

[0080] 11 , the remaining film ratio is expressed by the following formula (1): remaining film ratio=(N1+N2+N3+ ... +NZ) / (NTa×Z) (1) Here, N1 is the number of pixels of the remaining film R in the target region Ta of image Pa-1, N2 is the number of pixels of the remaining film R in the target region Ta of image Pa-2, N3 is the number of pixels of the remaining film R in the target region Ta of image Pa-3, NZ is the number of pixels of the remaining film R in the target region Ta of image Pa-Z, NTa is the number of pixels in the target region Ta, and Z is the number of images. The number of pixels NTa in the target region Ta may be sent from the detection processing unit 87 to the control unit 20 together with the detection result of the remaining film, or may be stored in advance in the storage device 20a of the control unit 20.

[0081] The control unit 20 calculates the remaining film rate of the peripheral edge of the substrate W and, based on the remaining film rate, determines whether or not regrinding of the peripheral edge of the substrate W is necessary. For example, the control unit 20 calculates the remaining film rate of the peripheral edge of the substrate W and, when the remaining film rate is greater than a remaining film rate threshold, determines that regrinding of the peripheral edge of the substrate W is necessary. In the example shown in Fig. 11, the control unit 20 determines whether or not regrinding of the top edge E1 of the substrate W is necessary based on the remaining film rate of the top edge E1 of the substrate W calculated by the above formula (1).

[0082] In one embodiment, the control unit 20 may determine whether or not regrinding of the peripheral edge of the substrate W is necessary based on the thickness of the residual film R present on the peripheral edge of the substrate W. For example, the control unit 20 determines that regrinding of the peripheral edge of the substrate W is necessary when the thickness of the residual film R present on the peripheral edge of the substrate W is greater than a film thickness threshold. In this case, the average value of the thickness of the residual film R present within the target region of the image may be used as the thickness of the residual film R present on the peripheral edge of the substrate W.

[0083] The control unit 20 is configured to determine polishing conditions for regrinding the peripheral portion of the substrate W when it is determined that regrinding of the peripheral portion of the substrate W is necessary. Specifically, the control unit 20 is configured to determine a polishing time as a polishing condition for regrinding the peripheral portion of the substrate W, based on the remaining film rate on the peripheral portion of the substrate W and correlation data between the remaining film rate and the polishing time. The correlation data between the remaining film rate and the polishing time is obtained in advance based on experimental results, etc., and stored in the storage device 20a of the control unit 20. The correlation data between the remaining film rate and the polishing time is data indicating a relationship in which the larger the remaining film rate on the peripheral portion of the substrate W, the longer the polishing time required for regrinding the peripheral portion of the substrate W.

[0084] In one embodiment, the control unit 20 may be configured to determine the polishing time as a polishing condition for regrinding the peripheral portion of the substrate W, based on the thickness of the residual film R present on the peripheral portion of the substrate W. In this case, the control unit 20 is configured to determine the polishing time as a polishing condition for regrinding the peripheral portion of the substrate W, based on the thickness of the residual film R present on the peripheral portion of the substrate W and correlation data between the thickness of the residual film R and the polishing time. The correlation data between the thickness of the residual film R and the polishing time is acquired in advance based on experimental results, etc., and stored in the storage device 20a of the control unit 20. The correlation data between the thickness of the residual film R and the polishing time is data indicating a relationship in which the greater the thickness of the residual film R on the peripheral portion of the substrate W, the longer the polishing time required for regrinding the peripheral portion of the substrate W.

[0085] In one embodiment, the control unit 20 may be configured to determine the polishing time based on a combination of the remaining film rate at the peripheral edge of the substrate W and the thickness of the remaining film R present at the peripheral edge of the substrate W.

[0086] Furthermore, the control unit 20 is configured to determine, as a polishing condition for regrinding, a polishing angle corresponding to the peripheral region of the substrate W determined to require regrinding. The polishing angle is the inclination angle of the polishing heads 30A to 30D. For example, when the control unit 20 determines that the top edge E1 of the substrate W requires regrinding, the control unit 20 determines, as a polishing condition for regrinding the peripheral region of the substrate W, the polishing angle corresponding to the top edge E1.

[0087] The polishing module 4A or 4B of the polishing unit 4 re-polishes the peripheral edge of the substrate W under the determined polishing conditions. Specifically, the polishing module 4A or 4B re-polishes the peripheral edge of the substrate W using at least one of the polishing heads 30A-30D for the determined polishing time and polishing angle. For example, the control unit 20 issues a command to the polishing head tilting mechanism 70A of the polishing module 4A to tilt the polishing head 30A to the determined polishing angle, and issues a command to the air cylinder 35 of the polishing head 30A to press the polishing tape 22A against the peripheral edge of the substrate W with the pressing member 32 for the determined polishing time. In this way, the polishing module 4A re-polishes the peripheral area of ​​the substrate W determined to require regrinding under the determined polishing conditions (polishing time and polishing angle).

[0088] 12 is a flowchart showing one embodiment of a substrate processing method. The processing flow described below is executed by the above-described substrate processing apparatus. In step S101, at least one of the polishing modules 4A and 4B of the polishing unit 4 polishes the peripheral portion of the substrate W according to a predetermined polishing recipe. In step S102, the cleaning unit 6 cleans the substrate W polished by at least one of the polishing modules 4A and 4B. In step S103, the drying unit 7 dries the substrate W cleaned by the cleaning unit 6.

[0089] In step S104, the residual film detection unit 9 detects a residual film on the peripheral edge of the substrate W. In one embodiment, the imaging devices 86A to 86E of the residual film detection unit 9 generate an image of the peripheral edge of the substrate W. The detection processing unit 87 of the residual film detection unit 9 detects the residual film from the hue that appears on the image of the peripheral edge of the substrate W. For example, the detection processing unit 87 may detect the residual film within a target region in the image of the peripheral edge of the substrate W, and calculate the area of ​​the residual film.

[0090] In step S105, the control unit 20 determines whether or not the peripheral portion of the substrate W needs to be re-polished, based on the result of the detection of the residual film by the residual film detection unit 9. In one embodiment, the control unit 20 determines whether or not the peripheral portion of the substrate W needs to be re-polished, based on a residual film ratio, which is the ratio of the area of ​​the residual film R in the target region to the total area of ​​the target region in the image.

[0091] When it is determined in step S105 that regrinding of the peripheral portion of the substrate W is necessary, the control unit 20 determines the polishing conditions for regrinding (step S106). In one embodiment, the control unit 20 determines the polishing time as the polishing conditions for regrinding of the peripheral portion of the substrate W, based on the remaining film rate of the peripheral portion of the substrate W and correlation data between the remaining film rate and the polishing time. Furthermore, the control unit 20 determines, as the polishing conditions for regrinding, a polishing angle corresponding to the region of the peripheral portion of the substrate W determined to be necessary for regrinding.

[0092] The polishing module 4A or 4B of the polishing unit 4 re-polishes the peripheral edge of the substrate W under the re-polishing polishing conditions determined in step S106 (return to step S101). Specifically, the polishing module 4A or 4B re-polishes the peripheral edge of the substrate W using at least one of the polishing heads 30A-30D for the determined polishing time and angle. Steps S102 to S105 are then performed again. The process flow repeats steps S101 to S106 until the control unit 20 determines in step S105 that re-polishing of the peripheral edge of the substrate W is not necessary.

[0093] The control unit 20 ends the process when it determines in step S105 that re-polishing of the peripheral portion of the substrate W is not necessary. Specifically, the control unit 20 issues a command to the first transport robot 14 to return the substrate W from the remaining film detection unit 9 to the substrate cassette 19 of the load port 2.

[0094] According to this embodiment, the control unit 20 can appropriately determine the polishing conditions for regrinding based on the state of the remaining film on the peripheral edge of the substrate W.

[0095] In one embodiment, as shown in FIG. 13 , the control unit 20 may have a polishing condition determination model 90 constructed by machine learning, and may output polishing conditions for re-polishing the peripheral portion of the substrate W from the polishing condition determination model 90. FIG. 13 is a schematic diagram showing one embodiment of the control unit 20 having the polishing condition determination model 90 and the residual film detection unit 9. The control unit 20 of this embodiment has the polishing condition determination model 90 stored in a storage device 20a. The polishing condition determination model 90 is a trained model constructed by machine learning. Examples of machine learning include the SVR method (support vector regression), the PLS method (partial least squares), the deep learning method, the random forest method, and the decision tree method. In one example, the polishing condition determination model 90 is composed of a neural network constructed by the deep learning method.

[0096] The training data used for machine learning of the polishing condition determination model 90 includes an image of the peripheral edge of the substrate and the polishing conditions (i.e., polishing time and polishing angle) required to remove the residual film that appears in the image by polishing. The image of the peripheral edge of the substrate is an explanatory variable, and the polishing conditions (i.e., polishing time and polishing angle) are objective variables. The polishing conditions included in the training data are correct labels and are obtained from the results of actual substrate polishing.

[0097] Fig. 14 is a schematic diagram showing an example of a polishing condition determination model 90 constructed using a deep learning method. The polishing condition determination model 90 has an input layer 91, a plurality of hidden layers (also called intermediate layers) 92, and an output layer 93. The polishing condition determination model 90 shown in Fig. 14 has four hidden layers 92, but the configuration of the polishing condition determination model 90 is not limited to the embodiment shown in Fig. 14.

[0098] The polishing condition determination model 90 is configured so that, when an image of the peripheral edge of a substrate is input to the input layer 91, polishing conditions (i.e., polishing time and polishing angle) for re-polishing the peripheral edge of the substrate are output from the output layer 93. The polishing condition determination model 90 using deep learning is constructed as follows. An image of the peripheral edge of the substrate is input to the input layer 91 shown in FIG. 14 . The control unit 20 compares the polishing conditions for re-polishing the peripheral edge of the substrate output from the output layer 93 with the polishing conditions (correct answer labels) corresponding to the image of the peripheral edge of the substrate included in the training data, and adjusts the parameters (weights, thresholds, etc.) of each node (neuron) to minimize the error. In this way, the polishing condition determination model 90 is trained to output appropriate polishing conditions for re-polishing the peripheral edge of the substrate from the output layer 93 based on the image of the peripheral edge of the substrate input to the input layer 91.

[0099] By repeating the above learning using images of the peripheral portion of a plurality of substrates, a polishing condition determination model 90 is constructed. A polishing condition determination model 90 based on machine learning generally has low prediction accuracy for input data that it has not experienced. Therefore, by using a large number of images in which residual films appear in different modes, the accuracy of the polishing conditions for re-polishing the peripheral portion of the substrate output from the polishing condition determination model 90 can be improved.

[0100] The polishing conditions for regrinding the peripheral portion of the substrate W using the polishing condition determination model 90 are determined as follows: The control unit 20 inputs images of the peripheral portion of the substrate W generated by the imaging devices 86A to 86E of the residual film detection unit 9 to the input layer 91 of the polishing condition determination model 90. In this embodiment, the detection result of the residual film on the peripheral portion of the substrate W by the residual film detection unit 9 is an image of a predetermined target area. The control unit 20 performs calculations in accordance with an algorithm defined by the polishing condition determination model 90. The control unit 20 outputs the polishing conditions for regrinding the peripheral portion of the substrate W from the output layer 93 of the polishing condition determination model 90, and determines the polishing conditions for regrinding the peripheral portion of the substrate W.

[0101] In one embodiment, the control unit 20 may output an estimated value of the thickness of the residual film in addition to the polishing conditions for the peripheral edge of the substrate W from the polishing condition determination model 90. In this case, the correct label used for the training data includes the actual measured value of the thickness of the residual film for the peripheral edge of the substrate and the polishing conditions (i.e., polishing time and polishing angle) required to remove the residual film that appears on the image by polishing.

[0102] In one embodiment, after the peripheral edge of the substrate W is re-polished under polishing conditions determined using the polishing condition determination model 90, the residual film on the peripheral edge of the substrate W may be detected again by the residual film detection unit 9. In this case, the polishing condition determination model 90 may be updated by machine learning using, as training data, an image of the peripheral edge of the substrate W before re-polishing and the detection result of the residual film after re-polishing.

[0103] The above-described embodiments have been described for the purpose of enabling a person of ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments would be obvious to a person skilled in the art, and the technical concept of the present invention may be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope in accordance with the technical concept defined by the claims.

[0104] The present invention can be used in a substrate processing apparatus and a substrate processing method for polishing a substrate such as a wafer.

[0105] REFERENCE SIGNS LIST 1 Housing 2 Load port 4 Polishing section 4A, 4B Polishing module 6 Cleaning section 7 Drying section 9 Residual film detection section 11 First temporary placement table 12 Second temporary placement table 14 First transfer robot 15 Second transfer robot 16 Third transfer robot 17 Fourth transfer robot 19 Substrate cassette 20 Control section 20a Storage device 20b Arithmetic unit 22A, 22B, 22C, 22D Polishing tape 25 Substrate holding section 27 Holding stage 28 Shaft 29 Holding stage driving mechanism 30A, 30B, 30C, 30D Polishing head 32 Pressing member 35 Air cylinder (actuator) 36 Tape feeding mechanism 38 Polishing head support member 40A, 40B, 40C, 40D Polishing tape supply mechanism 41 Tape unwinding reel 42 Tape winding reel 44, 45, 46, 47 Guide roller 48 Reel base 51 Lower supply nozzle 52 Upper supply nozzle 60 Polishing head translation mechanism 61 Movable plate 63 Connecting member 64 Guide rail 66 Connecting shaft 67 Air cylinder (actuator) 68 Base plate 70A, 70B, 70C, 70D Polishing head tilting mechanism 72 Crank arm 73 Arm rotation device 80 Substrate holding device 82 Holding stage 83 Shaft 84 Holding stage rotation mechanism 86A, 86B, 86C, 86D, 86E Imaging device 87 Detection processing unit 87a Storage device 87b Arithmetic unit 90 Polishing condition determination model 91 Input layer 92 Hidden layer (intermediate layer) 93 Output layer

Claims

1. A substrate processing apparatus comprising: a polishing unit that polishes a peripheral portion of a substrate; a residual film detection unit that detects a residual film on the peripheral portion of the substrate polished by the polishing unit; and a control unit that determines whether or not re-polishing of the peripheral portion of the substrate is necessary based on the detection result of the residual film by the residual film detection unit, and when it is determined that re-polishing is necessary, determines polishing conditions for the re-polishing based on the detection result of the residual film, wherein the polishing unit is configured to re-polish the peripheral portion of the substrate under the determined polishing conditions.

2. The substrate processing apparatus according to claim 1, wherein the residual film detection unit comprises: an imaging device that generates an image of the peripheral portion of the substrate; and a detection processing unit that detects the residual film on the peripheral portion of the substrate based on the image.

3. The substrate processing apparatus according to claim 2, wherein the residual film detection unit further comprises a substrate holding device that holds and rotates the substrate, and the image is an image of the entire circumference of the peripheral portion of the substrate.

4. The substrate processing apparatus of claim 2, wherein the detection processing unit is configured to calculate the area of ​​the remaining film from the hue appearing on the image, and the control unit is configured to determine whether or not the re-polishing of the peripheral portion of the substrate is necessary based on a remaining film rate, which is the ratio of the area of ​​the remaining film within the target area to the total area of ​​the target area in the image.

5. The substrate processing apparatus according to claim 4, wherein the control unit is configured to determine a polishing time as the polishing condition based on the remaining film rate and correlation data between the remaining film rate and the polishing time.

6. The substrate processing apparatus of claim 1, wherein the residual film detection unit is configured to detect the residual film in each of a plurality of regions of the peripheral portion aligned in the thickness direction of the substrate, and the control unit is configured to determine whether or not re-polishing is required in each of the plurality of regions based on the detection result of the residual film, and to determine a polishing angle corresponding to the region determined to require re-polishing as the polishing condition for the re-polishing, and the plurality of regions are regions polished at different polishing angles by the polishing unit.

7. The substrate processing apparatus of claim 6, wherein the residual film detection unit includes: a plurality of imaging devices that generate images of the plurality of regions, respectively; and a detection processing unit that detects the residual film in each of the plurality of regions based on the images of the plurality of regions.

8. The substrate processing apparatus of claim 1, wherein the residual film detection unit includes an imaging device that generates an image of the peripheral portion of the substrate, and a detection processing unit that detects the residual film on the peripheral portion of the substrate based on the image, and the control unit has a polishing condition determination model constructed by machine learning, and is configured to input the image into the polishing condition determination model and output the polishing conditions for re-polishing from the polishing condition determination model.

9. A substrate processing method comprising: detecting a remaining film on a peripheral portion of a substrate polished by a polishing unit; determining whether or not re-polishing of the peripheral portion of the substrate is necessary based on the detection result of the remaining film; when it is determined that re-polishing is necessary, determining polishing conditions for the re-polishing based on the detection result of the remaining film; and re-polishing the peripheral portion of the substrate under the determined polishing conditions by the polishing unit.

10. The substrate processing method of claim 9, wherein detecting the residual film on the peripheral edge of the substrate comprises generating an image of the peripheral edge of the substrate using an imaging device, and detecting the residual film on the peripheral edge of the substrate based on the image.

11. The substrate processing method of claim 10, wherein generating the image of the peripheral edge of the substrate comprises generating an image of the entire circumference of the peripheral edge of the substrate while rotating the substrate by a substrate holding device.

12. The substrate processing method of claim 10, wherein detecting the remaining film on the peripheral portion of the substrate comprises calculating an area of ​​the remaining film from a hue appearing on the image, and determining whether or not the peripheral portion of the substrate needs to be re-polished comprises determining whether or not the peripheral portion of the substrate needs to be re-polished based on a remaining film rate, which is the ratio of the area of ​​the remaining film within the target area to the total area of ​​the target area in the image.

13. The substrate processing method according to claim 12, wherein determining the polishing conditions for the re-polishing comprises determining a polishing time as the polishing condition based on the remaining film rate and correlation data between the remaining film rate and the polishing time.

14. The substrate processing method of claim 9, wherein detecting the residual film on the peripheral portion of the substrate comprises detecting the residual film in each of a plurality of regions on the peripheral portion aligned in the thickness direction of the substrate; determining whether or not re-polishing of the peripheral portion of the substrate is necessary comprises determining whether or not re-polishing is necessary in each of the plurality of regions based on a result of detecting the residual film; determining polishing conditions for the re-polishing includes determining, as the polishing conditions for the re-polishing, a polishing angle corresponding to the region determined to require re-polishing; and the plurality of regions are regions polished at different polishing angles by the polishing unit.

15. The substrate processing method of claim 9, wherein detecting the residual film on the peripheral edge of the substrate comprises generating an image of the peripheral edge of the substrate by an imaging device and detecting the residual film on the peripheral edge of the substrate based on the image, and determining the polishing conditions for the re-polishing comprises inputting the image into a polishing condition determination model constructed by machine learning and outputting the polishing conditions for the re-polishing from the polishing condition determination model.

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