Centering device

Abstract

This invention relates to a centering device using three or more abutment members, and to a portion thereof, wherein the abutment members are configured to surround a substrate support portion in a horizontal plane, on which a circular plate-shaped substrate with a notch at its periphery is mounted. In this invention, the three or more abutment members have abutment surfaces that can abut against the end face of the substrate, and are arranged to surround the substrate support portion in a horizontal plane with the abutment surfaces facing the end face of the substrate. Furthermore, the abutment area formed by the intersection of the abutment surfaces and the horizontal plane is a straight line or a curve with its center of curvature located on the substrate side and having a radius of curvature greater than the radius of the substrate, and is machined to be longer than the arc from which the circumference of the substrate is cut by the notch. This improves centering accuracy.

Description

Centering device The present invention relates to a centering technique for horizontally moving and positioning a circular plate-shaped substrate having a notch such as a notch provided at a peripheral portion in a state where the substrate is placed on the upper surface of a substrate support portion in a horizontal posture so that the center of the substrate coincides with the center of the substrate support portion, and a substrate processing apparatus for processing the substrate using this technique. This processing includes bevel etching processing. The disclosure contents in the specification, drawings, and claims of the following Japanese application are incorporated herein by reference in their entirety: Japanese Patent Application No. 2022-119717 (filed on July 27, 2022). There is known a substrate processing apparatus that rotates a substrate such as a semiconductor wafer and supplies a processing liquid to a peripheral portion of the substrate to perform chemical liquid processing or cleaning processing or the like. In the apparatus described in, for example, Japanese Patent Laid-Open No. 2019-149423, one surface of the substrate is supported from below by a rotating chuck (an example corresponding to the "substrate support portion" of the present invention) and adsorbed and held. At this time, if the center of the rotating chuck is offset from the center of the substrate, the processing quality will deteriorate. Therefore, in the above apparatus, before processing the substrate, a so-called centering process is performed to reduce the eccentricity of the substrate with respect to the rotating chuck. In the above prior apparatus, the centering process is performed in two stages. First, the eccentricity of the substrate with respect to the rotating chuck is measured. Next, by horizontally pushing the substrate on the rotating chuck with a pusher, the center of the substrate is moved toward the center (rotation axis) side of the rotating chuck. Therefore, there is still room for improvement in terms of productivity. Therefore, techniques for performing centering processing without measuring the eccentricity are constantly being studied. More specifically, three or more abutting members are provided to surround the rotating chuck in a horizontal plane. And, in a state where a substrate is placed on the rotating chuck, the substrate is clamped by moving the abutting members from different directions toward the end surface of the substrate. Thereby, only by the movement of the abutting members, the center of the circular plate-shaped substrate placed on the upper surface of the rotating chuck can be made to coincide with the center of the rotating chuck. However, when a notch such as a notch is provided in the substrate, although it will be described in detail with reference to FIG. 4 later, depending on the configuration of the abutting members, the centering accuracy is different. Therefore, in a centering device using three or more abutting members, in order to improve the centering accuracy, it is necessary to make efforts in the configuration of the abutting members. However, sufficient study has not been made on this point. The present invention was completed in view of the above problems, and its object is to improve the centering accuracy in a centering device using three or more abutting members and a substrate processing apparatus using this centering device, and the abutting members are provided to surround a substrate support portion on which a circular plate-shaped substrate having a notch provided at a peripheral portion is placed in a horizontal plane. The first aspect of the invention is a centering device that horizontally moves and positions a disk-shaped substrate with a notch at its peripheral edge on the upper surface of a substrate support portion in a horizontal posture, such that the center of the substrate coincides with the center of the substrate support portion, and includes: three or more abutting members, which have abutting surfaces that can abut against the end surface of the substrate and are arranged to surround the substrate support portion in a horizontal plane with the abutting surfaces facing the end surface of the substrate; a moving mechanism that moves the abutting members toward the substrate from different directions; and a control unit that controls the moving mechanism such that the abutting members move toward the substrate to clamp the substrate; the abutting region formed by the intersection of the abutting surface and the horizontal plane is a straight line or a curve with a center of curvature located on the substrate side and a radius of curvature greater than the radius of the substrate, and is processed to be longer than the arc of the circumference of the substrate cut by the notch. Furthermore, the second aspect of the invention is a substrate processing device, which includes: a substrate support portion having an upper surface that horizontally supports a disk-shaped substrate with a notch at its peripheral edge; the above-mentioned centering device; a suction portion that evacuates the space between the substrate positioned by the centering device and the substrate support portion and adsorbs and holds the substrate on the substrate support portion; a rotational drive portion that rotates the substrate support portion holding the substrate around the center of the substrate support portion; and a processing liquid supply mechanism that supplies processing liquid to the peripheral edge of the substrate that rotates integrally with the substrate support portion around the center of the substrate support portion. In the invention configured as described above, three or more abutting members having abutting surfaces that can abut against the end surface of the substrate are provided. These abutting members are arranged to surround the substrate support portion in a horizontal plane with the abutting surfaces facing the end surface of the substrate. Moreover, these abutting members move toward the substrate from different directions to clamp the substrate. At this time, if the abutting surface faces the notch of the substrate, it will be affected by the notch. However, in the present invention, the abutting region formed by the intersection of the abutting surface and the horizontal plane is a straight line or a curve with a center of curvature located on the substrate side and a radius of curvature greater than the radius of the substrate, and is processed to be longer than the arc of the circumference of the substrate cut by the notch. Therefore, it is possible to prevent a part of the abutting member from entering the notch, and as a result, the influence of the notch on the centering accuracy is suppressed. According to the present invention, the centering accuracy can be improved. Not all of the multiple components of the above aspects of the present invention are essential. To solve part or all of the above problems, or to achieve part or all of the effects described in this specification, it is possible to appropriately make changes, deletions, replacements with new other components, and deletions of part of the limited content to part of the multiple components. Also, to solve part or all of the above problems, or to achieve part or all of the effects described in this specification, it is also possible to combine part or all of the technical features included in one aspect of the present invention with part or all of the technical features included in other aspects of the present invention to form an independent form of the present invention. FIG. 1 is a diagram showing a substrate processing system of an embodiment of a substrate processing apparatus equipped with the present invention. The substrate processing system 100 includes: a substrate processing unit 110 that performs processing on a substrate S; and a transfer unit 120 that is combined with the substrate processing unit 110. The transfer unit 120 includes: a container holding unit 121 that can hold a plurality of containers C for storing the substrate S (FOUP (Front Opening Unified Pod) for storing a plurality of substrates S in a sealed state, SMIF (Standard Mechanical Interface) port, OC (Open Cassette), etc.); and a transfer robot 122 that is used to pick up the container C held in the container holding unit 121, take out the unprocessed substrate C from the container C, or store the processed substrate S in the container C. In each container C, a plurality of substrates S are stored in a substantially horizontal posture. The transfer robot 122 includes: a base portion 122a that is fixed to the apparatus housing; a multi-joint arm 122b that is provided so as to be rotatable relative to the base portion 122a about a vertical axis; and a hand 122c that is attached to the front end of the multi-joint arm 122b. The hand 122c is configured to place and hold the substrate S on its upper surface. Since a transfer robot having such a multi-joint arm and a hand for holding a substrate is well known, detailed description thereof is omitted. The substrate processing unit 110 includes: a substrate transfer robot 111 that is disposed substantially at the center in a plan view; and a plurality of processing units 1 that are disposed so as to surround the substrate transfer robot 111. Specifically, a plurality of processing units 1 are disposed facing the space where the substrate transfer robot 111 is disposed. The substrate transfer robot 111 randomly picks up and transfers the substrate S to and from the processing units 1. On the other hand, each processing unit 1 performs a predetermined process on the substrate S. In the present embodiment, one of the processing units 1 corresponds to the substrate processing apparatus 10 of the present invention. FIG. 2 is a diagram schematically showing the configuration of an embodiment of a substrate processing apparatus. FIG. 3 is a perspective view showing the configuration of a substrate holding unit and a centering mechanism of the substrate processing apparatus. FIG. 4 is a diagram schematically showing the relationship between the configuration of a contact member that can be adopted by the centering mechanism and the notch of the substrate. FIG. 5 is a diagram schematically showing the operation of the centering mechanism. FIG. 6 is a diagram schematically showing the positional relationship between the contact member and the center of the rotary base before and after fine movement. The substrate processing apparatus 10 is an apparatus that performs an oblique etching process as an example of "processing" of the present invention, and supplies a processing liquid to the peripheral portion of the upper surface of the substrate S in a processing chamber. For this purpose, the substrate processing apparatus 10 includes a substrate holding unit 2, a centering mechanism 3 which is the main configuration of the centering device of the present invention, and a processing liquid supply mechanism 4. These operations are controlled by a control unit 9 that controls the entire device. The substrate holding unit 2 includes a disk-shaped member, i.e., a rotary base 21, which is smaller than the substrate S. The rotary base 21 is supported by a rotary support shaft 22 extending downward from the central portion of its lower surface in such a manner that the upper surface 211 is horizontal. The rotary support shaft 22 is rotatably supported by a rotary drive unit 23. The rotary drive unit 23 incorporates a rotary motor 231 and rotates the rotary motor 231 according to a control command from the control unit 9. By receiving this rotary driving force, the rotary base 21 rotates around a vertical axis AX (dashed line) extending in the vertical direction through the center 21C of the rotary base 21. In FIG. 2, the up-down direction is the vertical direction. Also, the plane perpendicular to the paper surface in FIG. 2 is the horizontal plane. In addition, in order to clarify the direction relationship in the diagrams after FIG. 2, a coordinate system in which the Z-axis is set as the vertical direction and the XY plane is set as the horizontal plane is appropriately labeled. The upper surface 211 of the rotary base 21 has a size capable of supporting the substrate S, and the substrate S can be placed on the upper surface 211 of the rotary base 21. Although not shown in the figure, a plurality of suction holes or suction grooves or the like are provided on the upper surface 211. These suction holes or the like are connected to a suction pump 24 via a suction pipe 241. When the suction pump 24 operates according to a control command from the control unit 9, an attractive force is applied to the rotary base 21 from the suction pump 24. As a result, air is discharged between the upper surface 211 of the rotary base 21 and the lower surface of the substrate S, and the substrate S is adsorbed and held on the rotary base 21. The substrate S thus adsorbed and held rotates around the vertical axis AX together with the rotation of the rotary base 21. Therefore, when the center SC of the substrate S does not coincide with the center 21C of the rotary base 21, that is, when the substrate S is eccentric, the quality of the oblique etching process deteriorates. Therefore, in the present embodiment, a centering mechanism 3 is provided. The centering mechanism 3 performs a centering process during the period when the suction pump 24 stops suction (i.e., during the period when the substrate S can move horizontally on the upper surface 211 of the rotary base 21). By this centering process, the above-mentioned eccentricity is eliminated, and the center SC of the substrate S coincides with the center 21C of the rotary base 21. In addition, the detailed configuration and operation of the centering mechanism 3 will be described later. In order to perform an oblique etching process on the substrate S after receiving the centering process, a processing liquid supply mechanism 4 is provided. The processing liquid supply mechanism 4 includes: a processing liquid nozzle 41; a nozzle moving unit 42 that moves the processing liquid nozzle 41; and a processing liquid supply unit 43 that supplies the processing liquid to the processing liquid nozzle 41. The nozzle moving unit 42 moves the processing liquid nozzle 41 between a retracted position where it retracts from above the substrate S to the side as shown by the solid line in FIG. 2 and a processing position above the peripheral portion of the substrate S as shown by the dashed line in the figure. The processing liquid nozzle 41 is connected to the processing liquid supply unit 43. And, when an appropriate processing liquid is supplied from the processing liquid supply unit 43 to the processing liquid nozzle 41 positioned at the processing position, the processing liquid is ejected from the processing liquid nozzle 41 to the peripheral portion of the rotating substrate S. Thereby, an oblique etching process of the processing liquid is performed on the entire peripheral portion of the substrate S. In addition, although not shown in FIG. 2, a splash guard portion is provided so as to surround the substrate holding portion 2 from the side. During the oblique etching process, the splash guard portion captures the droplets of the processing liquid thrown off from the substrate S and effectively prevents the droplets from scattering to the periphery of the device. Next, with reference to FIGS. 2 to 6, the configuration of the centering mechanism 3 will be described. The centering mechanism 3 has the following function: to horizontally move and position the substrate S on the upper surface 211 of the rotary base 21 in such a manner that the center SC of the substrate S placed on the upper surface 211 of the rotary base 21 coincides with the center 21C of the rotary base 21. As shown in FIG. 3, the centering mechanism 3 includes: an abutting member 31 that is arranged on the X2 direction (the right side direction in the figure) side with respect to the center 21C of the rotary base 21 in the X direction; and abutting members 32 and 33 that are arranged on the X1 direction (the left side direction in the figure) side. Further, the centering mechanism 3 has a moving mechanism 34 for moving the abutting members 31 to 33 in the horizontal direction. The moving mechanism 34 includes: a single moving unit 35 for moving the abutting member 31; and a multi-moving unit 36 for moving the abutting members 32 and 33 together. The single moving unit 35 is arranged on the X2 direction side with respect to the center 21C of the rotary base 21, while the multi-moving unit 36 is arranged on the X1 direction side. The single moving part 35 includes a fixed base 351, a rotary motor 352, a power transmission part 353, and a slider 354. The rotary motor 352 is installed on the fixed base 351, and the power transmission part 353 and the slider 354 are stacked on the fixed base 351 in sequence. The rotary motor 352 is a drive source for moving the abutting member 31 in the X direction. When the rotary motor 352 operates according to a control instruction from the control unit 9, a rotary shaft (not shown) rotates. This rotary shaft extends from the upper part of the fixed base 351 to the power transmission part 353, and transmits the rotary driving force generated by the rotary motor 352 to the power transmission part 353. The power transmission part 353 converts the rotary motion corresponding to the rotary driving force into a linear motion in the X direction, for example, by means of a rack and pinion structure, etc., and transmits it to the slider 354. Thereby, the slider 354 reciprocally moves in the X direction by a distance corresponding to the amount of rotation. As a result, the abutting member 31 installed on the upper part of the slider 354 moves in the X direction as the slider 354 moves. The multi-moving part 36 has substantially the same configuration as the single moving part 35 except for a part of the structure of the slider 364 being different. That is, the multi-moving part 36 applies the rotary driving force generated by the rotary motor 362 installed on the fixed base 361 to the slider 364 through the power transmission part 363, causing the slider 364 to move in the X direction. In the upper part of the slider 364, two arms 364a and 364b extending in the X2 direction are spaced apart from each other in the Y direction and are substantially C-shaped when viewed from directly above. Also, the abutting members 32 and 33 are respectively installed at the ends on the X2 direction side of the arms 364a and 364b. Therefore, when the rotary motor 362 operates according to a control instruction from the control unit 9, similar to the single moving part 35, the slider 364 reciprocally moves in the X direction by a distance corresponding to the amount of rotation of the rotary motor 362. As a result, the abutting members 32 and 33 installed on the slider 364 move in the X direction as the slider 364 moves. Each of the abutting members 31 to 33 has an abutting surface 311 to 331 that can abut against the end surface Se of the substrate S. Further, the abutting members 31 to 33 are arranged in a posture with the abutting surfaces 311 to 331 facing the end surface Se of the substrate S so as to surround the substrate holding portion 2 in the XY plane (horizontal plane). The abutting surfaces 311 to 331 have a planar shape, and the normal vectors of these surfaces face the vertical axis AX. For example, as shown in the (a) column of FIG. 4, in the abutting surface 321, a linear region 322 that intersects the imaginary horizontal plane of the substrate S placed on the upper surface of the substrate holding portion 2 corresponds to an example of the "abuttable region" of the present invention, and its length L is longer than the length Ln of the arc of the circumference of the substrate S cut by the notch NT. Therefore, during centering, when the abutting member 32 moves toward the end surface Se of the substrate S, it abuts against the end surface Se of the substrate S at one or two points in the linear region 322. That is, as shown in the figure, when the substrate S is placed on the upper surface of the rotary base 21 with the notch NT facing the abutting surface 321, two abutting points CP1 and CP2 on the linear region 322 abut against the end surface Se of the substrate S. On the other hand, in other cases, one abutting point on the linear region 322 abuts against the end surface Se of the substrate S. The same applies to the abutting surfaces 311 and 331. Further, the reason for configuring the abutting members 31 to 33 as described above will be described in detail with reference to FIG. 4 later. When the abutting member 31 is moved in the X1 direction by the single moving portion 35, the abutting surface 311 of the abutting member 31 travels toward the center 21C of the rotary base 21 and abuts against the end surface Se of the substrate S. Thus, in the present embodiment, the moving direction D1 of the abutting member 31 for abutting against the substrate S is the X1 direction, which corresponds to the "first horizontal direction" of the present invention. Further, after abutting, the abutting member 31 is further moved in the D1 direction, pressing the substrate S in the X1 direction while causing it to horizontally move in the X1 direction on the upper surface 211 of the rotary base 21. Thus, in the present embodiment, for the sake of helping to understand the content of the invention, an imaginary line VL extending in the X1 direction from the center 21C of the rotary base 21 is additionally shown in FIGS. 3, 5, and 6. This corresponds to the "imaginary line" of the present invention. Hereinafter, while appropriately using the imaginary line VL, the configuration of the centering mechanism 3 will be continued to be described. A portion of the moving dynamics of the buckling members 32 , 33 produced by resorting to the multi-moving parts 36 is different from that of the buckling members 31 . The reason is that within the horizontal plane, the counterattack members 32 , 33 are symmetrically configured relative to the imaginary line VL line and move in the X direction, keeping their configuration state unchanged. In more detail, the counterattack member 32, shown in column (a) of Fig. 5 , is configured to deviate from the prescribed distance W (where, shorter than the radius rs of the substrate S) from the imaginary line VL sideways toward Y2. On the other hand, the counterattack member 33 is configured on the opposite side with respect to the imaginary line VL toward the counterattack member 32 , i.e., the Y1 direction side deviates by the same distance W as the counterattack member 32 . Accordingly, if the resisting members 32 , 33 are moved toward the X2 direction by means of the multi-moving portion 36 , the resisting surface 321 of the counterattacking member 32 is against the end face of the substrate on the side more imaginary line VL against Y2, and Thus, in this embodiment, the direction D2 of movement of the buckling member 32 used to counterbalance with the substrate S is the X2 direction, which is equivalent to the "2nd horizontal direction" of the invention. Also, the direction of movement D3 of the counter-connected member 33 used to counter with the substrate S is also in the X2 direction, which is equivalent to the "3rd horizontal direction" of the present invention. Therefore, in order to ensure the same distance from the center 21C of the rotating base 21 to each counter-face surface 311 , 321 , 331 on the one hand, and to move the counter-face surfaces 311 , 321 , 331 on the one hand, it is necessary to make the movement of the counter-member 31 different per unit time in the counter-members 32 , 33 . A detailed description of this point will be referred to Figs. In order to load the substrate S on the upper surface 211 of the rotating base 21 , it is desirable to locate the counterattack surfaces 311 , 321 , 331 in the datum position by considering at least the maximum value of the outer diameter tolerance of the substrate S . For example, in a substrate S with a diameter of 300 mm, the outer diameter tolerance is 0.2 mm. Therefore, the counter-joint surfaces 311 , 321 , 331 require a distance of 150.1 mm or more from the center 21C of the rotating base 21 . In this embodiment the distance is referred to as "datum distance r0", as shown in column (a) of FIG. 5. The circle (one point lock line) is set as the datum circle and the radius of the circle centered on the center 21C of the rotating base 21 is the datum distance r0. Next, after positioning the abutting members 31 to 33 such that the abutting surfaces 311, 321, and 331 are located on the reference circle, the case where the abutting surfaces 311, 321, and 331 are moved toward the substrate S will be discussed. In this case, the position of the abutting member 31 for positioning the abutting surface 311 on the reference circle corresponds to the "first reference position" of the present invention, the position of the abutting member 32 for positioning the abutting surface 321 on the reference circle corresponds to the "second reference position" of the present invention, and the position of the abutting member 33 for positioning the abutting surface 331 on the reference circle corresponds to the "third reference position" of the present invention. Here, the case where the abutting member 31 is slightly moved by a first movement amount Δd1 in the D1 direction (X1 direction) toward the substrate S from the state where the abutting members 31 to 33 are respectively located at the first reference position, the second reference position, and the third reference position will be discussed. Correspondingly, when the abutting members 32 and 33 are slightly moved by the same distance in the D2 direction (X2 direction), the distances from the center 21C of the rotating base 21 to the abutting surfaces 311, 321, and 331 are not the same. Therefore, if the movement amount per unit time is directly unified and the slight movement of the abutting members 31 to 33 is repeated, the center SC of the substrate S will not coincide with the center 21C of the rotating base 21. In contrast, as shown in the (b) column of FIG. 5 and FIG. 6, by corresponding to the slight movement of the abutting member 31 by the first movement amount Δd1 in the D1 direction, the abutting member 32 is slightly moved by a second movement amount Δd2 in the D2 direction, and the abutting member 33 is slightly moved by a third movement amount Δd3 (=Δd2) in the D3 direction, it is possible to move the abutting surfaces 311, 321, and 331 while ensuring that the distances from the center 21C of the rotating base 21 to the respective abutting surfaces 311, 321, and 331 are the same. FIG. 6 is a diagram schematically showing the positional relationship between the abutting member 32 and the center 21C of the rotating base 21 before and after the slight movement. FIG. 6 shows the positional relationship between the circle with a radius of r1 centered on the center 21C of the rotating base 21 and the abutting member 32, and the positional relationship between the circle with a radius of r2 centered on the center 21C of the rotating base 21 and the abutting member 32. In FIG. 6, the abutting member 32 before the slight movement in the D2 direction by the second movement amount Δd2 is shown by a solid line, and the abutting member 32 after the slight movement is shown by a two-dot chain line. FIG. 6 shows the tangent point 324 of the circle with a radius of r1 centered on the center 21C of the rotating base 21 and the abutting member 32, and the tangent point 325 of the circle with a radius of r2 centered on the center 21C of the rotating base 21 and the abutting member 32. As shown in FIG. 6, the positions of the tangent points 324 and 325 on the abutting member 32 are different. On the other hand, the straight line connecting the center 21C of the rotary base 21 and the tangent point 324 overlaps with the straight line connecting the center 21C of the rotary base 21 and the tangent point 325. Furthermore, the angles formed by the straight line connecting the center 21C of the rotary base 21 and the tangent point 324 with the imaginary line VL, and the angle formed by the straight line connecting the center 21C of the rotary base 21 and the tangent point 325 with the imaginary line VL are the same. Therefore, the distance Δd2 (corresponding to the "second movement amount" of the present invention) for slightly moving the abutting member 32 and the distance Δd3 (corresponding to the "third movement amount" of the present invention) for slightly moving the abutting member 33 can be set as follows. Here, r1: the distance from the center 21C before the slight movement to the abutting surface 321, θ: the angle formed by the straight line connecting the center 21C of the rotary base 21, the tangent point 325, and the tangent point 324 with the imaginary line VL, r2: the distance from the center 21C after the slight movement to the abutting surface 321, W: the separation distance between the abutting member 32 and the imaginary line VL. In this case, after the slight movement, the distances from the center 21C of the rotary base 21 to the abutting surfaces 311, 321, and 331 also coincide. By repeating such slight movements, while ensuring that the distances from the center 21C of the rotary base 21 to the abutting surfaces 311, 321, and 331 are the same, the abutting members 31 to 33 are brought closer to the substrate S. Thus, for example, when eccentricity as shown in FIG. 5 occurs, during the repetition of the above-described slight movements, first, the abutting member 31 abuts on the substrate S, causing the substrate S to move in the D1 direction (refer to the (c) column of FIG. 5). Next, the abutting member 32 abuts on the substrate S pushed by the abutting member 31 and causes it to move horizontally. And, as shown in the (d) column of FIG. 5, when the distances from the center 21C of the rotary base 21 to the abutting surfaces 311, 321, and 331 become the radius of the substrate S, the last abutting member 33 also abuts on the substrate S. Thus, the movement of the substrate S is stopped by clamping the substrate S with the abutting members 31 to 33, and the center SC of the substrate S coincides with the center 21C of the rotary base 21. Thus, centering processing of the substrate S can be performed. In the present embodiment having the above-described centering mechanism 3, the control unit 9 controls each device unit of the substrate processing apparatus 10 to perform the above-described centering processing and the subsequent bevel etching processing. In this control unit 9, an arithmetic processing unit 91 composed of a computer having a CPU (= Central Processing Unit: central processing unit) or a RAM (= Random Access Memory: random access memory), a memory unit 92 such as a hard disk drive, and a motor control unit 93 are provided. The operation processing unit 91 appropriately reads out the centering program or the bevel etching program previously stored in the memory unit 92, expands it in the RAM (not shown), and performs the centering process and the bevel etching process shown in FIG. 5. In particular, when performing the centering process, the operation processing unit 91 calculates the first movement amount Δd1 to the third movement amount Δd3, and based on these movement amounts Δd1 to Δd3, controls the rotation motors 352 and 362 of the movement mechanism 34 via the motor control unit 93. Further, the operation processing unit 91 calculates the load torque of the single movement unit 35 from the motor current value applied to the rotation motor 352, and calculates the load torque of the multi-movement unit 36 from the motor current value applied to the rotation motor 362. Here, during the period of repeating the minute movement, as the distance from the center 21C of the rotation base 21 to the contact surfaces 311, 321, 331 (the distance from the base center to the contact surface) changes, the load torque varies as shown in FIG. 7, for example. As shown in the figure, the above distance coincides with the radius rs of the substrate S, that is, at the time when the substrate S is clamped by the contact members 31 to 33, the load torque suddenly increases almost simultaneously in the single movement unit 35 and the multi-movement unit 36. Therefore, the operation processing unit 91 determines that the centering process is completed when the load torque exceeds the threshold value, and stops the movement of the contact members 31 to 33. In addition, in the present embodiment, although the variation of the load torque is monitored for all the motors 352 and 362, the timing of stopping the movement of the contact members 31 to 33 may be specified by monitoring only one motor. Of course, the load torque may also be calculated based on values other than the motor current value. As described above, in the present embodiment, by repeating the minute movement of the contact members 31 to 33, while ensuring that the distances from the center 21C of the rotation base 21 to the contact surfaces 311, 321, 331 are the same, the contact members 31 to 33 are gradually brought closer to the substrate S. And, by clamping the substrate S with these three contact members 31 to 33, the center SC of the substrate S is made to coincide with the center 21C of the rotation base 21. In this way, the centering process can be performed only by repeating the minute movement of the contact members 31 to 33, and the centering process can be performed with excellent productivity (operational effect A). Further, based on the variation of the load torque, the completion of the centering process is confirmed, and the movement of the contact members 31 to 33 is immediately stopped. Therefore, the centering process can be terminated at an appropriate timing without damaging the substrate S (operational effect B). The same applies to the embodiments described later. Furthermore, as shown in column (a) of FIG. 4, since the abutting members 31 to 33 have linear regions 312, 322, and 332 formed by intersecting the XY plane, other effects can be obtained. As a technique for pushing the end face Se of the substrate S in the horizontal direction to move it, generally, an abutting member having a front end portion processed into a semi-disk shape (refer to column (b) of FIG. 4) or a front end portion processed into a sharp shape, or an abutting member having a roller shape is used. Therefore, by using the abutting members having such shapes, the above-described effect A and effect B can be obtained. However, for example, in the comparative example shown in column (b) of FIG. 4, the front end portion 393 of the abutting member 39 has a semi-disk shape. In the abutting member 39, the abutting surface 391 facing the end face Se of the substrate S is processed into a convex shape toward the substrate S. Therefore, in the abutting surface 391, the curved region 392 intersecting the imaginary horizontal plane of the substrate S including the upper surface of the substrate holding portion 2 has a curved shape with the center of curvature located on the side of the abutting member 39. Therefore, when the substrate is placed on the upper surface of the rotating base 21 in a posture where the notch NT faces the abutting surface 391, a part of the front end portion 393 abuts at two abutting points CP1 and CP2 on the curved region 392 in a state of entering the notch NT. As a result, during centering, the abutting surface 391 moves to a position P1 that is eccentrically deviated by an amount Lb toward the substrate S from the position P0 where it abuts and is positioned against the end face Se of the substrate S. As a result, the pressing position of the abutting member 39 is shifted from the position used for accurate centering processing. For example, in the centering mechanism 3 shown in FIG. 3, if all the abutting members 31 to 33 are replaced with the abutting member 39 and centering processing is performed, the following experimental results can be obtained. Here, if the substrate (semiconductor wafer with a radius of 150 mm) S placed on the rotating base 21 is rotated by an appropriate rotation angle (for example, 32°, 180°, 328°) about the vertical axis AX, and centering processing is performed in a state where the notch NT faces the abutting surface 391, the amount of deviation of the pressing position, that is, the eccentric deviation amount also reaches a maximum of 240 μm. Therefore, in this embodiment, the abutting surfaces 311 to 331 of the abutting members 31 to 33 have a planar shape. Thus, as shown in column (a) of FIG. 4, the regions (which are examples of the "abuttable regions" of the present invention) of the abutting surfaces 311 to 331 that intersect with the imaginary horizontal plane of the substrate S placed on the upper surface of the substrate holding portion 2 are linear shapes respectively. Moreover, these linear regions 312, 321, and 332 are all longer than the length Ln of the arc. Therefore, as shown in the figure, when placed on the upper surface of the rotating base 21 in a posture where the notch NT faces the abutting surface 321, the two abutting points CP1 and CP2 on the linear region 322 are engaged by the shoulder portions of the notch NT, effectively preventing a part of the abutting member 32 from entering the notch NT. Also, although the abutting surface 321 moves to a position P2 that is eccentrically offset by an amount La toward the substrate S side from the position P0 where it abuts against and is positioned with respect to the end face Se of the substrate S, the eccentric offset amount La is significantly reduced compared to the eccentric offset amount Lb of the comparative example. Here, in the centering mechanism 3 shown in FIG. 3, if the substrate (a semiconductor wafer with a radius of 150 mm) S placed on the rotating base 21 is rotated about the vertical axis AX while switching the rotation angle at intervals of 0.25° within the range of 326.25° to 329.75° and the eccentricity and the eccentric direction are measured, the experimental results shown in FIG. 8 can be obtained. FIG. 8 is a graph showing the eccentricity and the eccentric direction corresponding to the positional relationship between the notch and the abutting surface. In the figure, the rotation angle shows the positional relationship between the notch NT and the abutting surface 321. At 328°, as shown in FIG. 4, the entire notch NT faces the abutting surface 321. At 327.25° or less or 328.75° or more, the notch NT deviates from the abutting surface 321 in the circumferential direction of the substrate S. Also, in the figure, the diamond marks represent the eccentricity after the centering operation, and the square marks represent the eccentric direction after the centering operation. It can be seen from the figure that even when the centering process is performed with the notch NT facing the abutting surface 321, the eccentricity can be suppressed to about 11 μm at most. That is, by using the abutting member 32 having the abutting surface 321 configured as described above, the eccentric offset amount can be significantly suppressed regardless of the position of the notch NT. The same applies to the abutting surface 311 of the abutting member 31 and the abutting surface 331 of the abutting member 33. As a result, by performing the centering process while clamping the substrate S placed on the upper surface of the rotating base 21 with these abutting surfaces 311, 321, and 331, the centering accuracy can be significantly improved compared to the comparative example. However, the combination of the above-described centering mechanism 3 and the control unit 9 corresponds to the first embodiment of the centering device of the present invention. However, the configuration of the abutting surfaces 311, 321, and 331 of the centering mechanism 3 is not limited thereto. For example, as shown in FIG. 9, the abutting surfaces 311, 321, and 331 (second embodiment) may be processed in such a way that the abuttable regions intersecting the XY plane become curves. FIG. 9 schematically shows the configuration of the abutting member and the relationship with the notch of the substrate in the second embodiment of the centering device of the present invention. A major difference between the second embodiment and the first embodiment is that the abutting surfaces 311, 321, and 331 have a curved shape along the end surface Se of the substrate S, and other configurations are the same as those in the first embodiment. Therefore, hereinafter, the description will focus on the differences, and the same components will be denoted by the same reference numerals and the description will be omitted. As shown in column (a) of FIG. 9, in the abutting surface 321, the curved region 323 that intersects the imaginary horizontal plane of the substrate S placed on the upper surface of the substrate holding portion 2 corresponds to an example of the "abuttable region" of the present invention. That is, the abutting surface 321 is processed such that the center of curvature of the curved region 323 is located on the substrate S side and the radius of curvature of the curved region 323 is greater than the radius of the substrate S. Therefore, during centering, when the abutting member 32 moves toward the end surface Se of the substrate S, it abuts against the end surface Se of the substrate S at one or two points in the curved region 323. That is, as shown in the figure, when placed on the upper surface of the rotary base 21 with the notch NT facing the abutting surface 321, the two abutting points P1 and CP2 on the curved region 323 are engaged by the shoulder portion of the notch NT, effectively preventing a part of the abutting member 32 from entering the notch NT. Also, although the abutting surface 321 moves to a position P3 that is eccentrically offset by an amount Lc toward the substrate S from the position P0 where it abuts against and is positioned with respect to the end surface Se of the substrate S, the eccentric offset amount Lc is less than the eccentric offset amount La of the first embodiment. The same applies to the abutting surface 311 of the abutting member 31 and the abutting surface 331 of the abutting member 33. Here, if the eccentric offset amount of the notch NT (angle 1.119°) provided in the substrate (a semiconductor wafer with a radius of 150 mm) S is obtained while changing the radius of curvature in multiple stages, the experimental results shown in FIG. 10 can be obtained. FIG. 10 is a graph showing the change in the eccentric offset amount with respect to the curvature (radius of curvature) of the abutting surface. It can be seen from the figure that as the radius of curvature approaches the radius of the substrate S, the eccentric offset amount L becomes smaller. And, in the case where the radius of curvature is the same as the radius of the substrate S, theoretically it is not affected by the notch NT. However, considering the tolerance of the substrate S, in practice, the case where the radius of curvature is the same as the radius of the substrate S cannot be used. Therefore, in the second embodiment, the abutting surfaces 311, 321, and 331 are processed such that the radii of curvature of the curved regions 313, 323, and 333 are greater than the radius of the substrate S. As described above, in the substrate processing apparatus 10, the combination of the centering mechanism 3 and the control unit 9 corresponds to an embodiment of the centering device of the present invention. That is, the abutting members 31 to 33 respectively correspond to an example of the "first abutting member", the "second abutting member", and the "third abutting member" of the present invention. Further, the control unit 9 corresponds to an example of the "control unit" of the present invention. Further, the rotary base 21 and the center 21C respectively correspond to an example of the "substrate support portion" and the "center of the substrate support portion" of the present invention. Further, the suction pump 24 corresponds to an example of the "suction portion" of the present invention. In addition, in the above-described first embodiment, although the two abutting members 32 and 33 are moved in the D2 direction (X2 direction) and the D3 direction (X2 direction) by the multi-moving portion 36, instead of the multi-moving portion 36, a single moving portion for the abutting member 32 and a single moving portion for the abutting member 33 having the same configuration as the single moving portion 35 may be provided. In this case, the single moving portions provided for each of the abutting members 31 to 33 respectively correspond to an example of the "first single moving portion", the "second single moving portion", and the "third single moving portion" of the present invention. Further, when the single moving portion for the abutting member 32 and the single moving portion for the abutting member 33 are provided in this way, it is not necessary to unify both the D2 direction and the D3 direction into the X2 direction, and at least one of the D2 direction and the D3 direction can be changed from the X2 direction (third embodiment). FIG. 11 is a diagram schematically showing the configuration of the third embodiment of the centering device of the present invention. A major difference between the third embodiment and the first embodiment is that, instead of the multi-moving portion 36, a single moving portion 37 for the abutting member 32 and a single moving portion 38 for the abutting member 33 having the same configuration as the single moving portion 35 are provided, and both the D2 direction and the D3 direction are different from the X2 direction. In this second embodiment, the second movement amount and the third movement amount are set independently in the same manner as in the (a) and (b) columns of FIG. 5 and the discussion of the second movement amount and the third movement amount based thereon. Other configurations and operations are basically the same as those of the first embodiment. In the third embodiment configured as described above, while ensuring that the distances from the center 21C of the rotary base 21 to the abutting surfaces 311, 321, and 331 are the same, the abutting members 31 to 33 are brought into contact with the substrate S in sequence and the substrate S is clamped. Thereby, the center SC of the substrate S coincides with the center 21C of the rotary base 21. Therefore, the centering process can be performed by repeating the minute movement of the abutting members 31 to 33, and the centering process can be performed with excellent productivity. In addition, the present invention is not limited to the above-described embodiments, and various modifications can be made to the above as long as the gist thereof is not deviated from. For example, in the above-described embodiment, although the centering process is completed by clamping the substrate S by the abutting members 31 to 33 based on the detection of the load torque variation, the above detection can also be performed by other methods. For example, it can also be configured such that sensors such as dynamometers or strain gauges are provided on the single moving parts 35, 38 or the multiple moving parts 36, and when the substrate S is clamped by the abutting members 31 to 33, the sensors detect stress or strain and output a detection signal. In this case, the control unit 9 confirms whether the abutting members 31 to 33 clamp the substrate S based on the detection signal from the sensors. Furthermore, in the above-described embodiment, although the present invention is applied to the centering device provided in the substrate processing apparatus 10 that performs the crystal edge etching process, the centering device of the present invention can be applied to all centering techniques provided in the substrate processing apparatus that rotates a disk-shaped substrate while performing processing. Also, the centering device of the present invention can be used alone. Moreover, in the above-described embodiment, although three abutting members are used to center the substrate, the present invention can be applied to a centering device that uses four or more abutting members. As described above, although the invention has been described with reference to the specified embodiments, this description is not intended to be construed in a limiting sense. If the description of the invention is referred to, those skilled in the art can understand various variations of the embodiments similarly disclosed to other embodiments of the present invention. Therefore, it is considered that the appended claims include such variations or embodiments within the scope not departing from the true scope of the invention. The present invention can be applied to centering techniques and all substrate processing apparatuses that process substrates using such techniques, in which a disk-shaped substrate having a notch such as a notch provided at a peripheral portion is placed in a horizontal posture on the upper surface of a substrate support portion, and the substrate is horizontally moved and positioned so that the center of the substrate coincides with the center of the substrate support portion. 1: Processing unit 2: Substrate holding part 3: Centering mechanism 4: Processing liquid supply mechanism 9: Control unit (control part) 10: Substrate processing device 21: Rotating base (substrate support part) 21C: Center of (rotating base) 22: Rotating support shaft 23: Rotating drive part 24: Suction pump (suction part) 31: (First) contact member 32: (Second) contact member 33: (Third) contact member 34: Moving mechanism 35: Single moving part 36: Multiple moving part 37: Single moving part for contact member 38: Single moving part for contact member 39: Contact member 41: Processing liquid nozzle 42: Nozzle moving part 43: Processing liquid supply part 91: Arithmetic processing part 92: Memory part 93: Motor control part 100: Substrate processing system 110: Substrate processing part 111: Substrate transfer robot 120: Carrier part 121: Container holding part 122: Carrier robot 122a: Base part 122b: Multi-joint arm 122c: Hand 211: Upper surface of (rotating base) 231: Rotating motor 241: Suction pipe 311, 321, 331, 391: Contact surface of (contact member) 312, 313, 322, 332: Linear area (contactable area) 323, 333, 392: Curved area (contactable area) 324: Tangent point of a circle with radius r1 centered at the center 21C of the rotating base 21 and the contact member 32 325: Tangent point of a circle with radius r2 centered at the center 21C of the rotating base 21 and the contact member 32 351: Fixed base 352: Rotating motor 353: Power transmission part 354: Slide block 361: Fixed base 362: Rotating motor 363: Power transmission part 364: Slide block 364a: Arm 364b: Arm 393: Front end AX: Vertical axis C: Container CP1: Contact point CP2: Contact point D1: First horizontal direction D2: Second horizontal direction D3: Third horizontal direction L: Length La: Eccentric offset Lb: Eccentric deviation Lc: Eccentric offset Ln: Length NT: Notch (notched part) P0: Position P1: Position P2: Position P3: Position r0: Reference distance r1: Radius r2: Radius rs: Radius S: Substrate SC: Center of (substrate) Se: End face of (substrate) VL: Imaginary line W: Distance X1: Direction X2: Direction Y1: Direction Y2: Direction θ: Angle Δd1: First movement amount Δd2: Second movement amount Δd3: Third movement amount FIG. 1 is a diagram showing a substrate processing system according to an embodiment of a substrate processing apparatus equipped with the present invention. FIG. 2 is a diagram schematically showing the configuration of an embodiment of the substrate processing apparatus. FIG. 3 is a perspective view showing the configuration of a substrate holding unit and a centering mechanism of the substrate processing apparatus. FIGS. 4(a) and (b) are diagrams schematically showing the relationship between the configuration of a contact member that can be adopted in the centering mechanism and the notch of the substrate. FIGS. 5(a) to (d) are diagrams schematically showing the operation of the centering mechanism. FIG. 6 is a diagram schematically showing the positional relationship between the contact member and the center of the rotating base before and after fine movement. FIG. 7 is a graph showing the variation of the load torque with respect to the distance from the base center to the contact surface in the first embodiment. FIG. 8 is a graph showing the eccentricity and the eccentric direction corresponding to the positional relationship between the notch and the contact surface. FIGS. 9(a) and (b) are diagrams schematically showing the relationship between the configuration of a contact member adopted in the second embodiment of the centering device of the present invention and the notch of the substrate. FIG. 10 is a graph showing the variation of the eccentric offset with respect to the curvature of the contact surface. FIG. 11 is a diagram schematically showing the configuration of the third embodiment of the centering device of the present invention. 31: (First) Contact Member 32: (Second) Contact Member 33: (Third) Contact Member 39: Contact Member 311, 321, 331, 391: Contact Surfaces of (Contact Member) 312, 322, 332: Linear Regions (Contactable Regions) 392: Curved Region (Contactable Region) 393: Front End CP1: Contact Point CP2: Contact Point La: Eccentric Offset Lb: Eccentric Deviation Ln: Length of Arc NT: Notch (Cutout Portion) P0: Position P1: Position P2: Position S: Substrate Se: End Face of (Substrate)

Claims

1. A centering device, characterized in that it comprises: a first abutting member that abuts against the end face of a circular plate-shaped substrate placed horizontally on the upper surface of a substrate support; a single moving part that moves the first abutting member in a horizontal direction; a second abutting member and a third abutting member that abut against the end face of the substrate from the side of the first abutting member opposite to the substrate support; and multiple moving parts that move the second abutting member and the third abutting member integrally in an anti-horizontal direction opposite to the horizontal direction. The control unit controls the single moving part and the multiple moving parts to position the substrate on the substrate support by moving the first abutting member in the horizontal direction and the second and third abutting members in the opposite horizontal direction, so that the first abutting member, the second abutting member, and the third abutting member clamp the substrate and align the center of the substrate with the center of the substrate support; and the multiple moving parts have: The slider, which, when viewed from a vertical top, is supported integrally with the second and third abutting members and the first abutting member surrounding the center of the substrate support portion, and can move freely in the reverse horizontal direction; and the driving unit, which generates a driving force to move the slider in the reverse horizontal direction; and the upper part of the slider is provided with a first arm and a second arm that are spaced apart from each other in an orthogonal direction orthogonal to the reverse horizontal direction and extend in the reverse horizontal direction, having a generally C-shaped shape when viewed from a vertical top; and the second abutting member is provided on the first arm, and the third abutting member is provided on the second arm.

2. The centering device of claim 1, wherein the slider has a shape that is symmetrical with respect to the center of the substrate support portion and to a vertical imaginary plane that is parallel to the horizontal direction and the anti-horizontal direction.

3. A centering device, characterized in that it comprises: a first abutting member that abuts against the end face of a circular plate-shaped substrate placed horizontally on the upper surface of a substrate support; a single moving part that moves the first abutting member in a horizontal direction; a second abutting member and a third abutting member that abut against the end face of the substrate from the side of the first abutting member opposite to the substrate support; and multiple moving parts that move the second abutting member and the third abutting member integrally in an anti-horizontal direction opposite to the horizontal direction. The control unit controls the single moving part and the multiple moving parts to position the substrate on the substrate support by moving the first abutting member in the horizontal direction and the second and third abutting members in the opposite horizontal direction, so that the first abutting member, the second abutting member, and the third abutting member clamp the substrate and align the center of the substrate with the center of the substrate support; and the multiple moving parts have: The slider, viewed from a vertical top, is able to move freely in the reverse horizontal direction while being integrally supported by the second and third abutting members and the first abutting member surrounding the center of the substrate support portion; and the driving unit generates a driving force to move the slider in the reverse horizontal direction; and the slider has a shape that is symmetrical with respect to a vertical imaginary plane containing the center of the substrate support portion and parallel to the horizontal and reverse horizontal directions.

4. The centering device as claimed in claim 2 or 3, wherein the multiple moving parts further have a power transmission part disposed directly below the slider, which transmits the driving force generated by the driving part to the slider.

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