Substrate processing method and substrate processing apparatus

Abstract

To provide a substrate processing method which can monitor whether or not a substrate is properly held by a roller.SOLUTION: A substrate processing method brings three or more rollers 11a, 11b fixed to three or more eccentric shafts 13a, 13b including a reference shaft 13a and a movable shaft 13b into contact with a circumferential edge of a substrate W having a notch Nw, circularly moves the three or more rollers 11a, 11b to rotate the substrate W around the shaft center thereof, circularly moves the substrate W, brings a treatment tool 201 into contact with the substrate W rotated and circularly moved to process the substrate W, calculates the rotational speed of the substrate W on the basis of a measurement value of a notch detection sensor 77 for detecting that the notch Nw has passed through the movable shaft 13b during processing of the substrate W, and issues a warning when the calculated rotational speed of the substrate W deviates from an allowable range set to the theoretical rotational speed of the substrate W.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] In recent years, devices such as memory circuits, logic circuits, and image sensors (e.g., CMOS sensors) have been becoming more highly integrated. In the process of forming these devices, foreign substances such as fine particles and dust may adhere to the devices. The foreign substances adhering to the devices may cause a short circuit between wirings or a circuit failure. Therefore, in order to improve the reliability of the devices, it is necessary to clean the substrate (e.g., wafer) on which the devices are formed by bringing a processing tool (e.g., cleaning tool) into contact with the substrate to remove foreign substances on the substrate.

[0003] Foreign substances such as fine particles and dust as described above may also adhere to the back surface of the substrate (e.g., bare silicon surface). When such foreign substances adhere to the back surface of the substrate, the substrate may be separated from the stage reference surface of the exposure apparatus, or the surface of the substrate may be inclined with respect to the stage reference surface, resulting in a deviation in patterning or a deviation in focal length. In order to prevent such problems, it is necessary to bring a processing tool (e.g., polishing tool) into contact with the back surface of the substrate to remove the adhering foreign substances.

[0004] Recently, there has been a growing demand for equipment that can process the entire surface of a substrate more efficiently. Therefore, a substrate holding device has been proposed in which the peripheral edge of the substrate is gripped by multiple rollers connected to multiple eccentric shafts, and the substrate is rotated around its axis while the eccentric shafts themselves remain stationary, causing the substrate to move in a circular motion (see, for example, Patent Document 1). In a substrate processing device using such a substrate holding device, the rollers do not come into contact with the processing tool, allowing the processing tool to process the entire surface of the substrate, including the outermost edges. Furthermore, this combination of circular motion and rotation around the substrate's axis can increase the speed at each point on the substrate's surface, thereby improving the efficiency of substrate processing. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-2639 [Overview of the project] [Problems that the invention aims to solve]

[0006] When a substrate is rotated around its axis by rotating it in a circular motion using multiple rollers connected to multiple eccentric shafts, it is possible to indirectly determine the rotational speed of the substrate based on the ratio of the substrate's diameter to the roller's diameter and the roller's rotational speed. On the other hand, directly measuring the substrate's rotational speed is difficult. Therefore, conventional substrate processing equipment adjusts the theoretical rotational speed of the substrate to match the set rotational speed by controlling the rotational speed of the rollers.

[0007] However, the actual rotational speed of the substrate may deviate from the theoretical rotational speed. Examples of causes for the actual rotational speed deviating from the theoretical rotational speed include: (1) manufacturing and / or processing errors between each roller (e.g., errors in the diameter of the substrate contact surface between each roller), (2) errors in the diameter (or circumference) between each substrate, (3) slippage of the substrate on the substrate contact surface of the roller due to a decrease in the substrate gripping force of the roller, (4) slippage of the substrate on the substrate contact surface of the roller due to the magnitude of the frictional force between the processing tool and the substrate surface, and (5) wear of the substrate contact surface of the roller (change in roller diameter).

[0008] If the actual rotational speed of the substrate deviates from the theoretical rotational speed, it may negatively affect the processing performance of the substrate (e.g., cleaning performance or polishing performance). For example, in a substrate processing apparatus that polishes the back surface of the substrate along with foreign matter by contacting a polishing tool with the back surface of the substrate, if the rotational speed of the substrate decreases relative to the rotational speed of the substrate's circular motion, it is expected that the polishing rate of the substrate will decrease.

[0009] Therefore, the present invention aims to provide a substrate processing method and a substrate processing apparatus that can monitor whether or not the substrate is properly held by the rollers. [Means for solving the problem]

[0010] In one embodiment, a substrate processing method is provided, in which three or more rollers fixed to three or more eccentric shafts, each including at least one reference shaft and at least one movable shaft displaceable toward and toward the reference shaft, are brought into contact with the peripheral edge of a substrate having a notch, each of the eccentric shafts having a first shaft portion connected to an electric motor and a second shaft portion eccentric to the first shaft portion and to which the rollers are fixed, the first shaft portions of the three or more eccentric shafts are rotated around their respective axes to cause the three or more rollers to move in a circular motion, thereby rotating the substrate around its axis and causing the substrate to move in a circular motion, a processing tool is brought into contact with the rotating and circularly moving substrate to process the substrate, the rotation speed of the substrate is calculated based on a measurement value of a notch detection sensor that detects when the notch has passed the movable shaft during the processing of the substrate, and an alarm is issued if the calculated rotation speed of the substrate deviates from an allowable range set for the theoretical rotation speed of the substrate.

[0011] In one embodiment, the substrate processing method further includes a step of performing additional processing on the substrate based on the difference or ratio between the rotation speed of the substrate and the theoretical rotation speed when the calculated rotation speed of the substrate falls below the lower limit of the allowable range. In one embodiment, the notch detection sensor is an acceleration sensor that measures the acceleration generated when the movable axis moves toward and toward the reference axis. In one embodiment, the notch detection sensor is a distance sensor that measures the distance traveled by the movable axis when the movable axis moves toward and toward the reference axis.

[0012] In one embodiment, three or more rollers fixed to three or more eccentric shafts, each including at least one reference shaft and at least one movable shaft displaceable toward and toward the reference shaft, are brought into contact with the peripheral edge of a substrate having a notch, each of the eccentric shafts having a first shaft portion connected to an electric motor and a second shaft portion eccentric to the first shaft portion and to which the rollers are fixed, and the first shaft portions of the three or more eccentric shafts are rotated around their respective axes, causing the three or more rollers to move in a circular motion, thereby rotating the substrate around its axis, and the base A substrate processing method is provided, which involves moving a plate in a circular motion, bringing a processing tool into contact with the rotating and circularly moving substrate to process the substrate, measuring the distance traveled by the movable axis with a distance sensor during the processing of the substrate, detecting when the notch has passed the movable axis with a notch detection sensor, issuing an alarm if the measurement value of the distance sensor deviates from a predetermined tolerance range and the notch detection sensor does not detect the notch, and not issuing an alarm if the measurement value of the distance sensor deviates from a predetermined tolerance range and the notch detection sensor detects the notch. In one embodiment, during the predetermined rotation angle of the roller before and after the notch detection sensor detects the notch, the alarm is canceled even if the measurement value of the distance sensor deviates from a predetermined tolerance range.

[0013] In one embodiment, three or more rollers fixed to three or more eccentric shafts, each including at least one reference shaft and at least one movable shaft displaceable toward and toward the reference shaft, are brought into contact with the peripheral edge of a substrate having a notch, each of the eccentric shafts having a first shaft portion connected to an electric motor and a second shaft portion eccentric to the first shaft portion and to which the rollers are fixed, and the substrate is rotated about its axis by rotating the first shaft portions of the three or more eccentric shafts about their respective axes, thereby causing the three or more rollers to move in a circular motion, and A substrate processing method is provided, comprising: rotating the substrate in a circular motion; processing the substrate by bringing a processing tool into contact with the rotating and circularly moving substrate; measuring the distance traveled by the movable axis with a distance sensor during the processing of the substrate; detecting that the notch has passed the movable axis with the distance sensor; issuing an alarm if the measurement value of the distance sensor deviates from a predetermined tolerance range and the distance sensor does not detect the notch; and not issuing an alarm if the measurement value of the distance sensor deviates from a predetermined tolerance range and the distance sensor detects the notch. In one embodiment, during a predetermined rotation angle of the roller before and after the detection of the notch by the distance sensor, the alarm is canceled even if the measurement value of the distance sensor deviates from a predetermined tolerance range.

[0014] In one embodiment, the system includes three or more eccentric shafts, each having a first shaft portion and a second shaft portion eccentric to the first shaft portion, each including at least one reference shaft and at least one movable shaft; three or more rollers fixed to the second shaft portions of the three or more eccentric shafts and capable of contacting the peripheral edge of a substrate having a notch; three or more electric motors that rotate the first shaft portions of the three or more eccentric shafts around their respective axes, causing the three or more rollers to move in a circular motion, thereby rotating the substrate around its axis and causing the substrate to move in a circular motion; and the system brings the at least one movable shaft closer to the reference shaft. A substrate processing apparatus is provided, comprising: an actuator that displaces in the direction toward and away from the substrate; a processing tool that contacts the surface of the rotating and circularly moving substrate and processes the surface of the substrate; a notch detection sensor that detects when the notch has passed the movable axis; and a control device to which the notch detection sensor is connected, wherein the control device calculates the rotational speed of the substrate based on the measurement value of the notch detection sensor during processing of the substrate, and issues an alarm if the calculated rotational speed of the substrate deviates from an allowable range set for the theoretical rotational speed of the substrate.

[0015] In one embodiment, if the calculated rotational speed of the substrate falls below the lower limit of the allowable range, the control device performs additional processing on the substrate based on the difference or ratio between the rotational speed of the substrate and the theoretical rotational speed. In one embodiment, the notch detection sensor is an acceleration sensor that measures the acceleration generated when the movable axis moves toward and toward the reference axis. In one embodiment, the notch detection sensor is a distance sensor that measures the distance traveled by the movable axis when the movable axis moves toward and toward the reference axis.

[0016] In one embodiment, the system includes at least one reference axis and at least one movable axis, and comprises three or more eccentric axes, each having a first axis portion and a second axis portion eccentric from the first axis portion; three or more rollers fixed to the second axis portions of the three or more eccentric axes and capable of contacting the peripheral edge of a substrate having a notch; three or more electric motors that rotate the first axis portions of the three or more eccentric axes around their respective axes, causing the three or more rollers to move in a circular motion, thereby rotating the substrate around its axis and causing the substrate to move in a circular motion; actuators that displace the at least one movable axis in a direction toward and away from the reference axis; and contacts the surface of the rotating and circularly moving substrate, A substrate processing apparatus is provided, comprising: a processing tool for processing the surface of a board; a notch detection sensor for detecting when the notch has passed the movable axis; a distance sensor for measuring the distance traveled by the movable axis when it moves toward and toward the reference axis; and a control device to which the notch detection sensor and the distance sensor are connected, wherein the control device issues an alarm if, during processing of the substrate, the measurement value of the distance sensor deviates from a predetermined tolerance range and the notch detection sensor does not detect the notch, and does not issue an alarm if, during processing of the substrate, the measurement value of the distance sensor deviates from a predetermined tolerance range and the notch detection sensor detects the notch. In one embodiment, the control device cancels the alarm even if the measurement value of the distance sensor deviates from a predetermined tolerance range during a predetermined rotation angle of the roller before and after the notch detection sensor detects the notch.

[0017] In one embodiment, the system includes at least one reference axis and at least one movable axis, and comprises three or more eccentric axes, each having a first axis portion and a second axis portion eccentric from the first axis portion; three or more rollers fixed to the second axis portions of the three or more eccentric axes and capable of contacting the peripheral edge of a substrate having a notch; three or more electric motors that rotate the first axis portions of the three or more eccentric axes around their respective axes, causing the three or more rollers to move in a circular motion, thereby rotating the substrate around its axis and causing the substrate to move in a circular motion; an actuator that displaces the at least one movable axis in a direction toward and away from the reference axis; and the rotating and circularly moving base A substrate processing apparatus is provided, comprising: a processing tool that contacts the surface of a board and processes the surface of the substrate; a distance sensor that measures the distance traveled by the movable axis as the movable axis moves toward and toward the reference axis, and detects when the notch has passed the movable axis; and a control device to which the distance sensor is connected, wherein the control device issues an alarm if, during processing of the substrate, the measurement value of the distance sensor deviates from a predetermined tolerance range and the distance sensor does not detect the notch, and does not issue an alarm if, during processing of the substrate, the measurement value of the distance sensor deviates from a predetermined tolerance range and the distance sensor detects the notch. In one embodiment, the control unit cancels the alarm even if the measurement value of the distance sensor deviates from a predetermined tolerance range during a predetermined rotation angle of the roller before and after the detection of the notch of the distance sensor. [Effects of the Invention]

[0018] According to the present invention, a notch detection sensor or distance sensor monitors whether the substrate is rotating normally, and an alarm is issued if an abnormality occurs in the rotation of the wafer W. As a result, the substrate can be processed while monitoring whether the substrate is properly held by the rollers. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is a schematic plan view showing a substrate processing apparatus according to one embodiment. [Figure 2] Figure 2 is a side view of the substrate processing apparatus shown in Figure 1. [Figure 3] Figure 3 is a bottom view of the substrate processing apparatus shown in Figure 1. [Figure 4] Figures 4(a) to 4(d) are schematic diagrams for explaining the operation of the substrate holding device for receiving a wafer. [Figure 5] Figure 5 is a schematic diagram showing the actuator 18 according to an embodiment. [Figure 6] Figure 6 is a cross-sectional view schematically showing a partition film according to an embodiment. [Figure 7] Figure 7(a) is a diagram showing the state of the actuator when the pressure in the first pressure chamber is higher than the pressure in the second pressure chamber, and Figure 7(b) is a diagram showing the state of the actuator when the pressure in the second pressure chamber is higher than the pressure in the first pressure chamber. [Figure 8] Figure 8 is a graph showing an example of the measured value of the notch detection sensor. [Figure 9] Figure 9 is a graph showing an example of the measured value of the distance sensor. [Figure 10] Figure 10 is a schematic diagram showing another example of the distance sensor. [Figure 11] Figure 11(a) is a diagram showing an example of the measured value of the distance sensor, and Figure 11(b) is a diagram showing an example of the measured value of the notch detection sensor.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1 is a plan view schematically showing a substrate processing apparatus according to an embodiment, Figure 2 is a side view of the substrate processing apparatus shown in Figure 1, and Figure 3 is a bottom view of the substrate processing apparatus shown in Figure 1. In Figure 3, the illustration of the processing tool shown in Figure 1 is omitted. The substrate processing apparatus 100 shown in Figures 1 to 3 includes a substrate holding device 10 configured to rotate the wafer W, which is an example of a substrate, in a circular motion while holding the wafer W and to rotate the wafer W about its axis center.

[0021] The substrate holding device 10 includes a plurality of rollers 11a, 11b that can contact the peripheral edge of the wafer W, a plurality of electric motors 29a, 29b that rotate the plurality of rollers 11a, 11b, a plurality of eccentric shafts 13a, 13b that connect the plurality of rollers 11a, 11b and the plurality of electric motors 29a, 29b, and a control device 40 that rotates the plurality of electric motors 29a, 29b at the same speed and with the same phase.

[0022] The control unit 40 consists of at least one computer. The control unit 40 includes a storage device 40a and an arithmetic unit 40b. The arithmetic unit 40b includes a CPU (Central Processing Unit) or GPU (Graphics Processing Unit), etc., which performs calculations according to instructions contained in the program stored in the storage device 40a. The storage device 40a includes main memory (e.g., random access memory) accessible by the arithmetic unit 40b and auxiliary storage (e.g., a hard disk drive or solid-state drive) for storing data and programs.

[0023] Roller 11a has a wafer holding surface (substrate holding surface) 31a that holds the peripheral edge of the wafer W, and roller 11b has a wafer holding surface (substrate holding surface) 31b that holds the peripheral edge of the wafer W. Rollers 11a and 11b have the same configuration and the same size. Multiple eccentric axes 13a and 13b are arranged around a predetermined central axis CP of the substrate holding device 10.

[0024] The substrate holding device 10 of this embodiment includes two rollers 11a, two rollers 11b, two eccentric shafts 13a, two eccentric shafts 13b, two electric motors 29a, and two electric motors 29b, but the number of these components is not limited to this embodiment.

[0025] Each of the multiple eccentric shafts 13a has a first shaft portion 14a, a second shaft portion 15a eccentric to the first shaft portion 14a, and an intermediate shaft portion 16a connecting the first shaft portion 14a and the second shaft portion 15a. At least two of the first shaft portion 14a, the second shaft portion 15a, and the intermediate shaft portion 16a may be a single integrated structure. For example, the first shaft portion 14a and the intermediate shaft portion 16a may be a single integrated structure. In other examples, the entirety of the first shaft portion 14a, the second shaft portion 15a, and the intermediate shaft portion 16a may be a single integrated structure. Although each eccentric shaft 13a shown in Figure 2 has the shape of a crankshaft, the shape of each eccentric shaft 13a is not limited to this embodiment, as long as the second shaft portion 15a is eccentric by a predetermined distance from the first shaft portion 14a.

[0026] Multiple rollers 11a are fixed to one end of multiple second shafts 15a, and the other ends of the multiple second shafts 15a are fixed to multiple intermediate shafts 16a. One end of multiple first shafts 14a is connected to multiple electric motors 29a via multiple couplings 28a, and the other ends of the multiple first shafts 14a are fixed to multiple intermediate shafts 16a.

[0027] Each of the multiple eccentric shafts 13b has a first shaft portion 14b, a second shaft portion 15b eccentric to the first shaft portion 14b, and an intermediate shaft portion 16b connecting the first shaft portion 14b and the second shaft portion 15b. At least two of the first shaft portion 14b, the second shaft portion 15b, and the intermediate shaft portion 16b may be a single integrated structure. For example, the first shaft portion 14b and the intermediate shaft portion 16b may be a single integrated structure. In other examples, the entirety of the first shaft portion 14b, the second shaft portion 15b, and the intermediate shaft portion 16b may be a single integrated structure. Although each eccentric shaft 13b shown in Figure 2 has the shape of a crankshaft, the shape of each eccentric shaft 13b is not limited to this embodiment, as long as the second shaft portion 15b is eccentric by a predetermined distance from the first shaft portion 14b.

[0028] Multiple rollers 11b are fixed to one end of multiple second shafts 15b, and the other ends of the multiple second shafts 15b are fixed to multiple intermediate shafts 16b. One end of multiple first shafts 14b is connected to multiple electric motors 29b via multiple couplings 28b, and the other ends of the multiple first shafts 14b are fixed to multiple intermediate shafts 16b.

[0029] The electric motor 29a is configured to rotate its eccentric shaft 13a around its first shaft portion 14a, and the electric motor 29b is configured to rotate its eccentric shaft 13b around its first shaft portion 14b. The electric motors 29a and 29b are connected to the control device 40.

[0030] The second shaft portion 15a of the eccentric shaft 13a is eccentric by a distance e from the first shaft portion 14a. Therefore, when the electric motor 29a is operated, the roller 11a rotates around the second shaft portion 15a and performs circular motion with radius e. The axis of the roller 11a coincides with the axis of the second shaft portion 15a. That is, the roller 11a rotates around its axis and performs circular motion with radius e around the axis of the first shaft portion 14a.

[0031] Similarly, the second shaft portion 15b of the eccentric shaft 13b is eccentric by a distance e from the first shaft portion 14b. Therefore, when the electric motor 29b is operated, the roller 11b rotates around the second shaft portion 15b and performs circular motion with radius e. The axis of the roller 11b coincides with the axis of the second shaft portion 15b. That is, the roller 11b rotates around its axis and performs circular motion with radius e around the axis of the first shaft portion 14b. In this specification, circular motion is defined as the motion of an object moving along a circular orbit.

[0032] The operation of motors 29a and 29b is controlled by the control device 40. As described above, the control device 40 rotates all motors 29a and 29b at the same speed and in the same phase. More specifically, the control device 40 issues commands to motors 29a and 29b to start all motors 29a and 29b at the same time and to rotate all motors 29a and 29b in the same direction. Furthermore, the control device 40 synchronizes the rotational speed and phase of motors 29a and 29b while they are operating.

[0033] As a result, all eccentric shafts 13a and 13b rotate in the same direction and at the same rotational speed and with the same phase around the axes of the first shafts 14a and 14b. All rollers 11a and 11b rotate in the same direction and at the same rotational speed and with the same phase around their axes, while simultaneously performing circular motion around the axes of the first shafts 14a and 14b. Therefore, when the wafer W is held by the rollers 11a and 11b, the control device 40 operates the electric motors 29a and 29b, causing the wafer W to rotate around its axis while performing circular motion with radius e.

[0034] Thus, the substrate holding device 10 can rotate the wafer W around its axis while causing it to move in a circular motion with a simple structure. This combination of circular motion and rotation around the axis of the wafer W can increase the speed at each point on the surface of the wafer W. Therefore, when the processing head 200, described later, is pressed against the surface of the wafer W, the relative speed between the processing head 200 and the surface of the wafer W increases, and the processing rate of the wafer W can be improved.

[0035] Counterweights 17a and 17b are fixed to multiple eccentric shafts 13a and 13b, respectively. More specifically, the counterweights 17a and 17b are fixed to intermediate shaft sections 16a and 16b, respectively. The counterweight 17a and roller 11a are arranged symmetrically with respect to the first shaft section 14a. The weight of the counterweight 17a is such that the centrifugal force generated radially from the first shaft section 14a toward the roller 11a when the eccentric shaft 13a rotates around the first shaft section 14a is canceled out by the centrifugal force acting on the counterweight 17a.

[0036] Similarly, the counterweight 17b and the roller 11b are arranged symmetrically with respect to the first shaft portion 14b. The weight of the counterweight 17b is such that the centrifugal force generated radially from the first shaft portion 14b toward the roller 11b when the eccentric shaft 13b rotates around the first shaft portion 14b is canceled out by the centrifugal force acting on the counterweight 17b. Such counterweights 17a and 17b can prevent vibration of the eccentric shafts 13a and 13b caused by weight imbalance when the eccentric shafts 13a and 13b are rotating.

[0037] The substrate holding device 10 further comprises a base plate 20, a plurality of linear motion guides 26 fixed to the lower surface of the base plate 20, a plurality of movable tables 21 supported by the plurality of linear motion guides 26, and a plurality of actuators 18 connected to the plurality of movable tables 21. The linear motion guides 26 restrict the movement of the movable tables 21 to linear motion in a direction parallel to the lower surface of the base plate 20.

[0038] Each movable base 21 has a bearing 24 that rotatably supports an eccentric shaft 13b and a connecting member 23 connected to an actuator 18. Multiple actuators 18 are each connected to multiple eccentric shafts 13b via multiple movable bases 21. Multiple movable bases 21, each containing multiple bearings 24, are moved independently by multiple actuators 18, together with the multiple eccentric shafts 13b.

[0039] The actuator 18 is fixed to the underside of the base plate 20. The operation of the actuator 18 is controlled by the control device 40. The control device 40 can operate each actuator 18 independently. The actuator 18 is configured to move the movable base 21 parallel to the base plate 20.

[0040] The eccentric shaft 13a extends through the base plate 20. The roller 11a is positioned above the base plate 20, and the electric motor 29a is positioned below the base plate 20. The eccentric shaft 13a is rotatably supported by a bearing 19 held in the base plate 20. The position of these eccentric shafts 13a is fixed. The electric motor 29a is fixed to the base plate 20 via an electric motor support 27a. More specifically, the electric motor support 27a is fixed to the lower surface of the base plate 20, and the electric motor 29a is fixed to the electric motor support 27a.

[0041] The eccentric shaft 13b extends through the movable base 21 and the base plate 20. The roller 11b is positioned above the base plate 20, and the electric motor 29b is positioned below the base plate 20. The eccentric shaft 13b is rotatably supported by a bearing 24 of the movable base 21. The electric motor 29b is fixed to the movable base 21 via an electric motor support 27b. More specifically, the electric motor support 27b is fixed to the underside of the movable base 21, and the electric motor 29b is fixed to the electric motor support 27b.

[0042] According to the above configuration, the eccentric shaft 13a is a reference shaft that is immovable relative to the base plate 20, and the eccentric shaft 13b is a movable shaft that is movable relative to the base plate 20. In the following description, the eccentric shaft 13a may be referred to as the reference shaft 13a, and the eccentric shaft 13b may be referred to as the movable shaft 13b. The actuator 18 is connected to the movable shaft 13b via a movable base 21. The movable base 21 has a bearing 24 that rotatably supports the movable shaft 13b and a connecting member 23 connected to the actuator 18. Therefore, the movable base 21 connects the actuator 18 and the movable shaft 13b.

[0043] The actuator 18 can move the movable shaft 13b parallel to the base plate 20 via the movable base 21. Specifically, the multiple actuators 18 are configured to move the multiple movable shafts 13b in a direction toward the multiple reference axes 13a and in a direction toward the multiple reference axes 13a. When the two movable shafts 13b move toward the two reference axes 13a, the wafer W is held by the two rollers 11a and the two rollers 11b. When the two movable shafts 13b move toward the two reference axes 13a, the wafer W is released from the two rollers 11a and the two rollers 11b.

[0044] As shown in Figure 3, in this embodiment, the actuator 18 and the linear guide 26 are arranged facing the central axis CP of the substrate holding device 10. The actuator 18 moves the movable shaft 13b in the direction of the arrow in Figure 3. In this embodiment, the direction towards the plurality of reference axes 13a and the direction away from the plurality of reference axes 13a are the direction toward the central axis CP and the direction away from the central axis CP. When the movable shaft 13b is moved toward the central axis CP, the roller 11b can hold the wafer W with a gripping force toward the center of the wafer W. According to the configuration of this embodiment, the substrate holding device 10 can efficiently hold the wafer W with minimal force. In one embodiment, each of the plurality of actuators 18 and the plurality of linear guides 26 may be arranged facing each of the plurality of reference axes 13a.

[0045] Figures 4(a) to 4(d) are schematic diagrams illustrating the operation of the substrate holding device 10 in receiving the wafer W. As shown in Figure 4(a), before receiving the wafer W, each actuator 18 (see Figures 2 and 3) is activated to move each roller 11b away from the central axis CP. At this time, rollers 11a and 11b are eccentrically positioned outward.

[0046] Next, as shown in Figure 4(b), the wafer W is transported to the substrate holding device 10 by a transport device (not shown). Furthermore, as shown in Figure 4(c), with the wafer W positioned between rollers 11a and 11b, the reference axis 13a is rotated 180 degrees to eccentrically move each roller 11a inward. Then, as shown in Figure 4(d), each actuator 18 is activated to move each roller 11b and each movable axis 13b toward each reference axis 13a until each roller 11b contacts the wafer W.

[0047] In this way, the peripheral edge of the wafer W is held by the wafer holding surface 31a of roller 11a and the wafer holding surface 31b of roller 11b. When removing the wafer W from the substrate holding device 10, the steps shown in Figures 4(a) to 4(d) are performed in the reverse order.

[0048] In the embodiment described above, the two movable shafts 13b are each supported by two movable bases 21 and further connected to two actuators 18. With this configuration, even if vibration occurs in one of the movable shafts 13b during the rotation of the wafer W, it is possible to prevent the vibration from propagating to the other movable shaft 13b. As a result, the substrate holding device 10 can stably hold the wafer W.

[0049] Figure 5 is a schematic diagram showing an actuator 18 according to one embodiment. Each actuator 18 comprises a piston 51 arranged in the longitudinal direction of the actuator 18, housings 52a and 52b arranged outside the piston 51, and diaphragms 55a and 55b that form pressure chambers 57a and 57b between the piston 51 and the housings 52a and 52b. The piston 51 is movable in the direction indicated by the arrow in Figure 5 (the longitudinal direction of the actuator 18). The housings 52a and 52b are arranged away from the piston 51. Housing 52a is arranged to surround one end of the piston 51, and housing 52b is arranged to surround the other end of the piston 51.

[0050] A connecting member 23 of the movable base 21 is connected to the piston 51, and the piston 51 is supported by the connecting member 23. The movable base 21, including the connecting member 23, is movable together with the piston 51 in the direction indicated by the arrow in Figure 5. More specifically, the movable base 21 is configured to be movable together with the piston 51 in a direction toward the reference axis 13a and in a direction toward the reference axis 13a. In this embodiment, since the actuator 18 is positioned facing the central axis CP of the substrate holding device 10 (see Figure 3), the directions of movement of the piston 51 and the movable base 21 are toward the central axis CP and away from the central axis CP.

[0051] The housings 52a and 52b comprise housing bodies 53a and 53b arranged to surround the sides of the piston 51, and lids 54a and 54b fixed to the housing bodies 53a and 53b. The edge of the partition membrane 55a is sandwiched between the housing body 53a and the lid 54a. Similarly, the edge of the partition membrane 55b is sandwiched between the housing body 53b and the lid 54b.

[0052] Pressure chamber 57a is formed by the partition membrane 55a and the inner surface of housing 52a. Similarly, pressure chamber 57b is formed by the partition membrane 55b and the inner surface of housing 52b. More specifically, pressure chamber 57a is formed by the partition membrane 55a and the inner surface of lid 54a, and pressure chamber 57b is formed by the partition membrane 55b and the inner surface of lid 54b. Partition membranes 55a and 55b have the same configuration. In this embodiment, housings 52a and 52b have the same configuration, but they may have different configurations.

[0053] Compressed gas passages 59a and 59b are formed in the lids 54a and 54b of the housings 52a and 52b. Compressed gas passages 59a and 59b are connected to a compressed gas supply source 64 via pressure regulators 62a and 62b and switching valves 63a and 63b. Pressure chambers 57a and 57b are in communication with pressure regulators 62a and 62b through compressed gas passages 59a and 59b.

[0054] When moving the piston 51, the switching valves 63a and 63b are operated to connect the pressure chambers 57a and 57b to the compressed gas supply source 64. In this embodiment, the switching valves 63a and 63b are connected to the control device 40. The switching valves 63a and 63b are valves that selectively connect the pressure chambers 57a and 57b to the compressed gas supply source 64 or the atmosphere. Three-way valves can be used as the switching valves 63a and 63b.

[0055] Compressed gas, such as compressed air, is supplied from a compressed gas supply source 64 through compressed gas passages 59a and 59b to pressure chambers 57a and 57b. Examples of the compressed gas supply source 64 include a pump or a pre-installed utility compressed gas supply line in the factory. The pressure of the compressed gas in pressure chambers 57a and 57b is controlled by pressure regulators 62a and 62b. In this embodiment, the pressure regulators 62a and 62b are electro-pneumatic regulators. In this embodiment, the pressure regulators 62a and 62b are connected to a control device 40. In one embodiment, the pressure regulators 62a and 62b may be manually operated pressure regulators. In this case, the pressure regulators 62a and 62b are not connected to the control device 40.

[0056] The control device 40 transmits a predetermined set pressure value to the pressure regulators 62a and 62b, and the pressure regulators 62a and 62b are configured to control the pressure of the compressed gas in the pressure chambers 57a and 57b according to the set pressure value. Examples of such pressure regulators 62a and 62b include electro-pneumatic regulators and mechanical regulators. In one embodiment, the pressure regulator 62b may be an electro-pneumatic regulator and the pressure regulator 62a may be a mechanical regulator. When the pressure regulator 62a is a mechanical regulator, the pressure regulator 62a is not connected to the control device 40.

[0057] The piston 51 moves according to the pressure difference between the pressure in pressure chamber 57a and the pressure in pressure chamber 57b. If the pressure in pressure chamber 57a is higher than the pressure in pressure chamber 57b, the piston 51 moves away from the reference axis 13a (see Figure 3). If the pressure in pressure chamber 57b is higher than the pressure in pressure chamber 57a, the piston 51 moves towards the reference axis 13a (see Figure 3).

[0058] In this embodiment, when the piston 51 is moved, compressed gas is introduced into both pressure chambers 57a and 57b, and the pressure of the compressed gas inside one of the pressure chambers 57a and 57b is made higher than the pressure of the compressed gas inside the other. In one embodiment, when the piston 51 is moved, compressed gas may be introduced into only one of the pressure chambers 57a and 57b, and the other may be connected to the atmosphere.

[0059] Figure 6 is a schematic cross-sectional view showing partition membranes 55a and 55b according to one embodiment. The partition membrane 55a has a central portion 71a that contacts one end of the piston 51, an inner wall portion 72a connected to the central portion 71a and extending along the side surface of the piston 51, a folded portion 73a connected to the inner wall portion 72a and having a curved cross-section, and an outer wall portion 74a connected to the folded portion 73a and located outside the inner wall portion 72a. The partition membrane 55a is in contact with one end of the piston 51. When compressed gas is introduced into the pressure chamber 57a, the outer wall portion 74a contacts the inner surface of the housing body 53a.

[0060] In this embodiment, the central portion 71a is circular. The inner wall portion 72a and the outer wall portion 74a have a cylindrical shape, and the inner wall portion 72a is in contact with the side surface of the piston 51. The outer wall portion 74a is arranged to surround the inner wall portion 72a.

[0061] Similarly, the partition membrane 55b has a central portion 71b that contacts the other end of the piston 51, an inner wall portion 72b connected to the central portion 71b and extending along the side of the piston 51, a folded portion 73b connected to the inner wall portion 72b and having a curved cross-section, and an outer wall portion 74b connected to the folded portion 73b and located outside the inner wall portion 72b. The partition membrane 55b is in contact with the other end of the piston 51. When compressed gas is introduced into the pressure chamber 57b, the outer wall portion 74b contacts the inner surface of the housing body 53b.

[0062] In this embodiment, the central portion 71b is circular. The inner wall portion 72b and the outer wall portion 74b have a cylindrical shape, and the inner wall portion 72b is in contact with the side surface of the piston 51. The outer wall portion 74b is arranged to surround the inner wall portion 72b.

[0063] The partition membranes 55a and 55b are in contact with the piston 51 but are not fixed to the piston 51. The thickened portion 75a that forms the edge of the partition membrane 55a is sandwiched between the housing body 53a and the lid 54a. Similarly, the thickened portion 75b that forms the edge of the partition membrane 55b is sandwiched between the housing body 53b and the lid 54b. The partition membranes 55a and 55b are formed from a flexible material. Examples of materials that make up the partition membranes 55a and 55b include chloroprene rubber, fluororubber, and silicone rubber. Chloroprene rubber, which has high resistance to bending fatigue, is preferably used.

[0064] Figure 7(a) shows the state of the actuator 18 when the pressure in pressure chamber 57a (first pressure chamber 57a) is higher than the pressure in pressure chamber 57b (second pressure chamber 57b), and Figure 7(b) shows the state of the actuator 18 when the pressure in pressure chamber 57b is higher than the pressure in pressure chamber 57a.

[0065] As shown in Figure 7(a), when the pressure in pressure chamber 57a becomes higher than the pressure in pressure chamber 57b, a force is applied to the piston 51 in the direction toward pressure chamber 57b. As a result, the partition membranes 55a and 55b deform, and the piston 51, movable base 21, and movable shaft 13b move together in a direction away from the reference shaft 13a (see Figure 3). At this time, the folded portion 73a maintains its shape, while a part of the inner wall portion 72a becomes part of the folded portion 73a, and a part of the folded portion 73a becomes part of the outer wall portion 74a. Simultaneously, the folded portion 73b maintains its shape, while a part of the outer wall portion 74b becomes part of the folded portion 73b, and a part of the folded portion 73b becomes part of the inner wall portion 72b.

[0066] As shown in Figure 7(b), when the pressure in the pressure chamber 57b becomes higher than the pressure in the pressure chamber 57a, a force is applied to the piston 51 in the direction toward the pressure chamber 57a. As a result, the partition membrane 55b deforms, and the piston 51, movable base 21, and movable shaft 13b move together toward the reference shaft 13a (see Figure 3). At this time, the folded portion 73b maintains its shape, while a part of the inner wall portion 72b becomes part of the folded portion 73b, and a part of the folded portion 73b becomes part of the outer wall portion 74b. Simultaneously, the folded portion 73a maintains its shape, while a part of the outer wall portion 74a becomes part of the folded portion 73a, and a part of the folded portion 73a becomes part of the inner wall portion 72a.

[0067] Due to the movement of the partition membranes 55a and 55b, the piston 51 can move smoothly with almost no reaction force from the partition membranes 55a and 55b. In a conventional air cylinder, if the piston and housing are in contact, sliding resistance will occur between the piston and housing if vibration occurs during wafer rotation. Such sliding resistance places an excessive load on the rotating wafer, causing instability in wafer holding. In this embodiment, since the housings 52a and 52b are positioned away from the piston 51, no sliding resistance occurs between the piston 51 and the housings 52a and 52b. As a result, the substrate holding device 10 can stably hold the wafer W without placing an excessive load on the wafer W.

[0068] In the embodiments shown in Figures 1 to 3, the substrate holder 10 comprises two reference axes 13a, two movable axes 13b, two actuators 18, two movable bases 21, and two linear guides 26 arranged around a central axis CP, but the number and spacing of these components are not limited to this embodiment. In one embodiment, the substrate holder 10 may comprise one movable axis 13b and two or more reference axes 13a arranged around a central axis CP at appropriate intervals. In this case, the substrate holder 10 comprises one actuator 18, one movable base 21, and one linear guide 26.

[0069] In one embodiment, the substrate holding device 10 may also include three or more movable axes 13b and three or more reference axes 13a arranged around a central axis CP at appropriate intervals. In this case, the substrate holding device 10 includes three or more actuators 18, three or more movable bases 21, and three or more linear guides 26.

[0070] In this embodiment, the substrate processing apparatus 100 further includes a processing head 200 that processes the first surface 1 of a wafer W held by a substrate holding device 10 by bringing a processing tool 201 into contact with the first surface 1 of the wafer W. The processing head 200 is positioned below the wafer W held by the substrate holding device 10, and the position of the processing head 200 is fixed.

[0071] The first surface 1 of the wafer W is the back surface of the wafer W, i.e., the non-device surface, on which no devices are formed or are not planned to be formed. The second surface 2 of the wafer W, opposite to the first surface 1, is the surface on which devices are formed or are planned to be formed, i.e., the device surface. The wafer W is held horizontally in the substrate holding device 10 with its first surface 1 facing downwards.

[0072] The specific operation of the substrate processing apparatus 100 according to this embodiment is as follows. The substrate holding apparatus 10 brings a plurality of rollers 11a, 11b into contact with the peripheral edge of the wafer W, and rotates the first shaft portions 14a, 14b of a plurality of eccentric shafts 13a, 13b around their respective axes, thereby causing the plurality of rollers 11a, 11b to move in a circular motion, and also causing the wafer W, which is gripped by the plurality of rollers 11a, 11b, to rotate around its axis. In this state, the processing head 200 brings the processing tool 201 into contact with the first surface 1 of the rotating and circularly moving wafer W to process the first surface 1 of the wafer W.

[0073] In this embodiment, the processing tool 201 is longer than the radius of the wafer W, with one end of the processing tool 201 extending outward from the periphery of the wafer W and the other end extending beyond the central axis CP of the substrate holding device 10. Therefore, the processing head 200 can bring the processing tool 201 into contact with the entire first surface 1 of the rotating wafer W. As a result, the processing tool 201 can process the entire first surface 1 of the wafer W, including the outermost part. The processing head 200 is positioned so as not to contact the rollers 11a, 11b and the eccentric axes 13a, 13b when the wafer W is in circular motion.

[0074] As described above, the substrate holding device 10 has a simple structure that allows the wafer W to rotate around its axis while simultaneously causing the wafer W to move in a circular motion. This combination of circular motion and rotation around the axis of the wafer W can increase the speed at each point on the surface of the wafer W. Therefore, the relative speed between the processing tool 201 and the surface of the wafer W increases, and the processing rate of the wafer W can be improved.

[0075] In one embodiment, the processing tool 201 may be a polishing tool for polishing the first surface 1 of the wafer W. Examples of polishing tools include polishing tape and grinding wheels. Furthermore, in one embodiment, the processing tool 201 may be a cleaning tool for cleaning the first surface 1 of the wafer W. An example of a cleaning tool is a cleaning tape. An example of a cleaning tape is a tape made of nonwoven fabric.

[0076] Although not shown in the figures, the substrate processing apparatus 100 may include a processing head 200 that processes the second surface 2 of the wafer W held by the substrate holding device 10 by bringing a processing tool 201 into contact with the second surface 2 of the wafer W. For example, the processing tool 201 may be a cleaning tool for cleaning the second surface 2 of the wafer W. In this case, the processing head 200 is positioned above the wafer W held by the substrate holding device 10.

[0077] As shown in Figure 2, the substrate holding device 10 of the substrate processing apparatus 100 has a notch detection sensor 77. In the example shown in Figure 2, the notch detection sensor 77 is attached to one of the movable shafts 13b. In one embodiment, the notch detection sensor 77 may be attached to the movable base 21, the motor support 27b, the coupling 28b, and the motor 29b.

[0078] The notch detection sensor 77 is a sensor capable of detecting when a notch Nw (see Figure 1) in the wafer W passes through the movable shaft 13b to which the notch detection sensor 77 is attached. The notch detection sensor 77 is connected to the control device 40 and transmits its measured values ​​to the control device 40. In the example shown in Figure 2, the notch detection sensor 77 is an acceleration sensor. In one embodiment, the notch detection sensor 77 may be a vibration sensor.

[0079] When a notch Nw in the wafer W passes over the movable shaft 13b to which the notch detection sensor 77 is attached, the movable shaft 13b moves in a direction toward or away from the reference shaft 13a, depending on the shape of the notch Nw (an arc shape in the example shown in Figure 1). As a result, a relatively large acceleration or vibration is generated in the movable shaft 13b.

[0080] Figure 8 is a graph showing an example of measurements from a notch detection sensor. In Figure 8, the vertical axis represents the horizontal acceleration of the movable shaft 13b to which the notch detection sensor 77 is attached, and the horizontal axis represents the rotation angle of the first shaft portion 14b of the movable shaft 13b to which the notch detection sensor 77 is attached.

[0081] In the graph shown in Figure 8, the characteristic multiple waveforms Pk1 with large peaks represent the passage of the notch Nw of the wafer W through the movable axis 13b. Hereafter, waveform Pk1 may be referred to as "passing waveform Pk1". Between adjacent passing waveforms Pk1, the wafer W held by the multiple rollers 11a and 11b completes one rotation. Typically, the roller 11b rotates multiple times between adjacent passing waveforms Pk1. The control device 40 can generate a graph like the one shown in Figure 8 from the measurements of the notch detection sensor 77.

[0082] The control device 40 monitors whether the wafer W is rotating at a desired rotational speed (or a set rotational speed) based on the measurement values ​​received from the notch detection sensor 77. For example, the control device 40 calculates the rotational speed of the wafer W based on the measurement values ​​received from the notch detection sensor 77, compares the calculated rotational speed of the wafer W with an allowable range determined for the theoretical rotational speed of the wafer W, and determines whether the wafer W is rotating at a desired rotational speed. The theoretical rotational speed of the wafer W can be calculated from the diameter of the wafer W, the diameters of the rollers 11a and 11b, and the rotational speeds of the electric motors 29a and 29b. Alternatively, the theoretical rotational speed of the wafer W may be calculated from the ratio of the diameter of the wafer W to the diameters of the rollers 11a and 11b, and the rotational speeds of the electric motors 29a and 29b. The control device 40 stores this theoretical rotational speed and an allowable range determined for the theoretical rotational speed in advance.

[0083] For example, the control device 40 can calculate the rotational speed of the wafer W from the number of passing waveforms Pk1 counted during a predetermined time interval (e.g., 10 seconds). In one embodiment, the time between adjacent passing waveforms Pk1 (i.e., the time it takes for the wafer W to complete one rotation) may be counted, and the rotational speed of the wafer W may be calculated based on this counted time.

[0084] The control device 40 is configured to compare the rotational speed of the wafer W, calculated based on the measurement value of the notch detection sensor 77, with an acceptable range, and to issue an alarm if the rotational speed of the wafer W deviates from the acceptable range. The alarm allows the operator of the substrate processing apparatus to recognize that a rotational abnormality has occurred in the wafer W, and as a result, to confirm whether or not a processing abnormality has occurred in the wafer W. In one embodiment, the control device 40 may issue an alarm and stop the processing operation of the wafer W. Alternatively, the control device 40 may store a signal to identify the wafer W that was being processed when the alarm was issued, associating it with the wafer W, and continue the processing operation of the wafer W.

[0085] Examples of causes where the rotational speed of the wafer W, calculated based on the measurements of the notch detection sensor 77, exceeds the upper limit of the permissible range include defects in the wafer W, defects in the rollers 11a and 11b, and abnormal rotation of the motors 29a and 29b. The alarm allows the operator to quickly check the condition of the wafer W, rollers 11a and 11b, and motors 29a and 29b, and perform maintenance and / or replacement of the rollers 11a and 11b and motors 29a and 29b as necessary.

[0086] Examples of causes for the wafer W rotation speed, calculated based on the measurement values ​​of the notch detection sensor 77, falling below the lower limit of the permissible range include wear of rollers 11a and 11b, and slippage between rollers 11a and 11b and wafer W. In this case, there is concern about a decrease in the processing performance of the substrate processing apparatus (for example, a decrease in polishing performance or a decrease in cleaning performance). The operator can identify the wafer W in which the rotation abnormality occurred through the alarm and confirm whether a processing abnormality has occurred in that wafer W.

[0087] In one embodiment, if the rotational speed of the wafer W calculated based on the measurement value of the notch detection sensor 77 falls below the lower limit of the allowable range, the control device 40 may perform additional processing on the wafer W based on the difference or ratio between the rotational speed of the wafer W calculated based on the measurement value of the notch detection sensor 77 and the theoretical rotational speed. For example, if the rotational speed of the wafer W calculated based on the measurement value of the notch detection sensor 77 is 10% lower than the theoretical rotational speed, the processing time may be increased by 10%. Alternatively, a relational expression or data table between the ratio of the actual rotational speed to the theoretical rotational speed and the increase in processing time may be determined by experiments conducted in advance, and this relational expression or data table may be stored in the control device 40 in advance. In this case, the control device 40 calculates the ratio of the rotational speed of the wafer W calculated based on the measurement value of the notch detection sensor 77 to the theoretical rotational speed, and calculates the increase in processing time from this ratio and the relational expression or data table.

[0088] In the embodiment described above, the control device 40 calculates the rotational speed of the wafer W based on the measurement value received from the notch detection sensor 77. However, in this specification, the rotational speed of the wafer W monitored by the control device 40 also includes a value corresponding to the rotational speed of the wafer W calculated based on the measurement value from the notch detection sensor 77. For example, the control device 40 may monitor the number of pass-through waveforms Pk1 counted during a predetermined time interval (e.g., 10 seconds). In this case, the control device 40 stores in advance the number of theoretical pass-through waveforms Pk1 calculated from the theoretical rotational speed of the wafer W and the tolerance range determined for the number of theoretical pass-through waveforms Pk1. The control device 40 compares the number of counted pass-through waveforms Pk1 with the tolerance range and issues an alarm if the number of counted pass-through waveforms Pk1 deviates from the tolerance range. As described above, the control device 40 may issue an alarm and stop the processing operation of the wafer W in the substrate processing apparatus, or it may store a signal to identify the wafer W that was being processed when the alarm was issued, associated with the wafer W, and continue the processing operation of the wafer W in the substrate processing apparatus.

[0089] Next, a substrate processing apparatus 100 according to another embodiment will be described. As shown in Figure 5, the substrate holding device 10 may be equipped with a non-contact distance sensor 80 that measures the travel distance of the movable axis 13b instead of the notch detection sensor 77 shown in Figure 2. In this case, the distance sensor 80 functions as a sensor capable of detecting the position of the movable axis 13a relative to the reference axis 13a, and is also used as a notch detection sensor capable of detecting that a notch Nw (see Figure 1) of the wafer W has passed through. The configuration of this embodiment, which will not be specifically described, is the same as the configuration of the substrate processing apparatus 100 having the notch detection sensor 77 shown in Figure 2, so a redundant explanation will be omitted.

[0090] The distance sensor 80 is located outside the actuator 18 and in the vicinity of the actuator 18 and the movable base 21. A magnet 81 is fixed to the connecting member 23 of the movable base 21, and the distance sensor 80 faces the magnet 81. In this embodiment, the distance sensor 80 is a magnetic sensor and can measure the relative movement distance of the magnet 81 with respect to the distance sensor 80.

[0091] The position of the distance sensor 80 is fixed. On the other hand, the movable base 21, piston 51, and movable shaft 13b are movable as a single unit. Therefore, when the movable shaft 13b moves toward or toward the reference shaft 13a, the relative position of the magnet 81 fixed to the movable base 21 with respect to the distance sensor 80 changes. The distance traveled by the magnet 81 corresponds to the distance traveled by the movable shaft 13b. Therefore, the distance sensor 80 can measure the distance traveled by the movable shaft 13b. The distance traveled by the movable shaft 13b is the relative position of the movable shaft 13b with respect to a predetermined reference position. Hereinafter, the relative position of the movable shaft 13b with respect to a predetermined reference position may simply be referred to as the position of the movable shaft 13b. The distance sensor 80 is connected to the control device 40, and the distance sensor 80 transmits the measured value of the distance traveled by the movable shaft 13b to the control device 40.

[0092] When a notch Nw in the wafer W passes over the movable shaft 13b, which is connected to the movable base 21 to which the magnet 81 is attached, the movable shaft 13b moves in a direction toward or away from the reference shaft 13a, depending on the shape of the notch Nw (an arc shape in the example shown in Figure 1). As a result, the distance sensor 80 can detect that the notch Nw has passed over the movable shaft 13b.

[0093] Figure 9 is a graph showing an example of measurement values ​​from the distance sensor shown in Figure 5. In Figure 9, the vertical axis represents the travel distance of the movable axis 13b to which the notch detection sensor 77 is attached, and the horizontal axis represents the rotation angle of the first axis portion 14b of the movable axis 13b.

[0094] As shown in Figure 9, the characteristic multiple waveforms Pk2 with large peaks represent the passage of the notch Nw of the wafer W through the movable axis 13b. Hereafter, waveform Pk2 may be referred to as "passed waveform Pk2". Between adjacent passed waveforms Pk2, the wafer W held by the multiple rollers 11a and 11b completes one rotation. Typically, the roller 11b rotates multiple times between adjacent passed waveforms Pk2, and the measurement value of the distance sensor 80 traces a roughly sinusoidal wave during one rotation of the roller 11b. The control device 40 can create a graph like the one shown in Figure 9 from the measurement value of the distance sensor 80.

[0095] Similar to the embodiments described above, the control device 40 calculates the rotational speed of the wafer W based, for example, on the number of passing waveforms Pk2 counted during a predetermined time interval (e.g., 10 seconds), or on the time between adjacent passing waveforms Pk2 (i.e., the time it takes for the wafer W to complete one rotation), and monitors whether the wafer W is rotating at a desired rotational speed (or a set rotational speed). Furthermore, the control device 40 compares the rotational speed of the wafer W calculated based on the measurement of the distance sensor 80 with an acceptable range determined for the theoretical rotational speed of the wafer W to determine whether the wafer W is rotating at a desired rotational speed.

[0096] Next, the control device 40 is configured to issue an alarm if the rotational speed of the wafer W, calculated based on the measurement value of the distance sensor 80, deviates from the acceptable range. In one embodiment, the control device 40 may issue an alarm and stop the processing operation of the wafer W, or it may store a signal associated with the wafer W to identify the wafer W that was being processed when the alarm was issued, and continue the processing operation of the wafer W. Furthermore, similar to the embodiments described above, if the rotational speed of the wafer W, calculated based on the measurement value of the distance sensor 80, falls below the lower limit of the acceptable range, the control device 40 may perform additional processing on the wafer W based on the difference or ratio between the rotational speed of the wafer W calculated based on the measurement value of the distance sensor 80 and the theoretical rotational speed. Furthermore, the control device 40 may monitor the number of passing waveforms Pk2 counted during a predetermined time interval (e.g., 10 seconds).

[0097] In one embodiment, as shown in Figure 10, the distance sensor 80 may be a non-contact optical sensor. The distance sensor 80 shown in Figure 10 includes a sensor head 84 having a light-emitting unit and a light-receiving unit (not shown) at its tip, a focusing lens 85 that focuses the light emitted from the sensor head 84, an amplifier 93 connected to the sensor head 84 by a light-emitting optical fiber cable 92A and a light-receiving optical fiber cable 92B, and a distance calculator 94 electrically connected to the amplifier 93. The focusing lens 85 is attached to the tip of the sensor head 84.

[0098] The sensor head 84 is fixed to the outside of the actuator 18, and its tip is positioned facing the movable base 21. More specifically, in this embodiment, a sensor target 88 is attached to the movable base 21, and the tip of the sensor head 84 is positioned facing the sensor target 88. The sensor target 88 has the property of reflecting light. An example of the sensor target 88 is a material made of ceramic or metal. The amplifier 93 and distance calculator 94 are located away from the actuator 18.

[0099] The amplifier 93 has a light source 93a that emits light and a light intensity meter 93b that measures the intensity of reflected light. The light emitted from the light source 93a of the amplifier 93 is transmitted to the sensor head 84 through the light-emitting optical fiber cable 92A. The sensor head 84 directs the light to the sensor target 88 through the focusing lens 85 and receives the reflected light from the sensor target 88. The reflected light is transmitted to the amplifier 93 through the light-receiving optical fiber cable 92B.

[0100] The light intensity meter 93b of amplifier 93 measures the intensity of reflected light. Amplifier 93 sends the measured value of the reflected light intensity to distance calculator 94, which converts the measured value of the reflected light intensity into a distance. The distance obtained by distance calculator 94 is the distance traveled by the movable axis 13b. In one embodiment, distance calculator 94 may be built into the control device 40. Alternatively, the control device 40 may have the function of distance calculator 94. In other words, the control device 40 may also function as a distance calculator. In these cases, amplifier 93 directly transmits the measured value of the reflected light intensity to the control device 40, and the distance is calculated within the control device 40.

[0101] With this configuration, the distance sensor 80 of this embodiment can measure the distance traveled by the movable axis 13b relative to the reference axis 13a. The distance calculator 94 is connected to the control device 40, and the distance calculator 94 transmits the measured value of the travel distance of the movable axis 13b to the control device 40. In one embodiment, the distance sensor 80 does not need to be equipped with a focusing lens 85. The sensor head 84 may guide light to the sensor target 88 without passing through the focusing lens 85 and may also receive reflected light from the sensor target 88 without passing through the focusing lens 85.

[0102] As described above, of the elements that make up the distance sensor 80, only the sensor head 84 is attached to the actuator 18. Since the sensor head 84 only has the function of emitting light and receiving reflected light, the sensor head 84 itself is very compact.

[0103] Next, a substrate processing apparatus according to another embodiment will be described. The configuration of this embodiment, which will not be specifically described, is the same as the configuration of the substrate processing apparatus 100 having the notch detection sensor 77 shown in Figure 2, so a redundant explanation will be omitted.

[0104] In this embodiment, the substrate holding device 10 of the substrate processing apparatus 100 includes a notch detection sensor 77 shown in Figure 2 and a distance sensor 80 shown in Figure 5 or Figure 10. The distance sensor 80 functions as a sensor for determining whether the rollers 11a and 11b of the substrate holding device 10 are correctly holding the wafer W.

[0105] As described above, the distance sensor 80 is connected to the control device 40, and the distance sensor 80 transmits a measured value of the travel distance of the movable axis 13b (a measured value of the position of the movable axis 13b) to the control device 40. The control device 40 can determine whether the substrate holding device 10 is properly holding the wafer W (for example, whether there is an abnormality in the substrate holding device 10) by comparing the measured value of the travel distance of the movable axis 13b (i.e., the position of the movable axis 13b) with a preset tolerance range. Furthermore, the control device 40 is configured to emit an alarm signal when the measured value of the travel distance deviates from the tolerance range.

[0106] If vibration occurs in the movable shaft 13b while the wafer W is rotating, the position of the movable shaft 13b (measured distance traveled by the movable shaft 13b) changes according to the vibration. Therefore, the control device 40 can detect vibration of the movable shaft 13b based on the change in the position of the movable shaft 13b (change in the measured distance traveled by the movable shaft 13b) while the wafer W is rotating. Based on the vibration of the movable shaft 13b, the control device 40 can detect abnormal rotation of the wafer W when the substrate holding device 10 is holding and rotating the wafer W. Possible causes of abnormal rotation of the wafer W include wear, deformation, damage, dimensional defects of the wafer holding surfaces 31a, 31b of the rollers 11a, 11b, or rotational phase misalignment of multiple rollers 11a, 11b.

[0107] Figure 11(a) shows an example of a measurement value from a distance sensor, and Figure 11(b) shows an example of a measurement value from a notch detection sensor 77. In Figure 11(a), the vertical axis represents the position of the movable shaft 13b to which the notch detection sensor 77 is attached, and the horizontal axis represents the rotation angle of the roller 11b fixed to one end of the movable shaft 13b. In Figure 11(b), the vertical axis represents the horizontal acceleration of the movable shaft 13b to which the notch detection sensor 77 is attached, and the horizontal axis represents the rotation angle of the roller 11b fixed to one end of the movable shaft 13b.

[0108] In Figure 11(a), the value indicating the position of the movable axis 13b decreases as the movable axis 13b approaches the reference axis 13a, and increases as the movable axis 13b moves away from the reference axis 13a. A position of 0 for the movable axis 13b means that within the movable range of the actuator 18, the movable axis 13b is closest to the reference axis 13a. A rotation angle of 0° for the roller 11b means that the roller 11b has a predetermined reference angle. In Figure 11(a), the dotted curve represents the measurement value of the distance sensor 80 when a rotational abnormality of the wafer W occurs. As shown in Figure 11(a), when a rotational abnormality of the wafer W occurs, the movable axis 13b vibrates greatly, and the position of the movable axis 13b fluctuates greatly. At this time, the amplitude of the position of the movable axis 13b deviates from the predetermined allowable range. On the other hand, when no abnormal rotation of the wafer W occurs, the amplitude of the position of the movable axis 13b remains within a predetermined tolerance range, as shown by the solid line in Figure 11(a).

[0109] The control device 40 compares the amplitude of the position of the movable axis 13b (measured distance traveled by the movable axis 13b) with a predetermined tolerance range, and determines that a rotational abnormality of the wafer W has occurred when the amplitude of the position of the movable axis 13b deviates from the tolerance range. In this specification, the amplitude of the position of the movable axis 13b is defined as the width of the vibration of the movable axis 13b. In the example shown in Figure 11(a), the amplitude of the movable axis 13b is the difference between the maximum value of the position of the movable axis 13b and the minimum value of the position of the movable axis 13b while the roller 11b is rotating for one or more rotations.

[0110] As described above, when the notch Nw of the wafer W passes through the movable axis 13b, a pass waveform Pk2 with a large peak is measured. This pass waveform Pk2 may deviate from the acceptable range. Since the pass waveform Pk2 is different from the waveform indicating a rotational abnormality of the wafer W, the control device 40 is configured not to issue an alarm if the measurement value of the distance sensor 80 deviates from a predetermined acceptable range and the distance sensor 80 detects the notch Nw.

[0111] In this embodiment, the control device 40 utilizes the pass waveform Pk1 measured by the notch detection sensor 77. Specifically, the control device 40 is configured to cancel the alarm even if the measurement value of the distance sensor 80 deviates from a predetermined tolerance range during a predetermined rotation angle (RA) of the roller 11b before and after the detection of the notch Nw by the notch detection sensor 77 (before and after the pass waveform Pk1). The predetermined rotation angle (RA) can be set arbitrarily. With this configuration, it is prevented that the pass waveform Pk2 measured when the notch passes the movable shaft 13b is judged to be an abnormal rotation of the wafer W.

[0112] In one embodiment, the notch detection sensor 77 may be omitted. In this case, the distance sensor 80 serves as both a sensor capable of detecting that the notch Nw of the wafer W has passed the movable axis 13b and a sensor for determining whether the rollers 11a and 11b of the substrate holding device 10 are correctly holding the wafer W.

[0113] The control device 40 is configured to cancel the alarm even if the measurement value of the distance sensor 80 deviates from a predetermined tolerance range during a predetermined rotation angle (RB) of the roller 11b before and after the detection of the notch Nw of the distance sensor 80 (before and after the passing waveform Pk2). More specifically, when a peak that deviates from the tolerance range (hereinafter referred to as a deviation peak) is detected, the control device 40 determines whether or not other peaks that deviate from the tolerance range are detected within the predetermined rotation angle (RB) range before and after the deviation peak. If no other peaks that deviate from the tolerance range are detected within the predetermined rotation angle (RB) range, the control device 40 determines that the deviation peak is the passing waveform Pk2 and does not issue an alarm (cancels it). If other peaks that deviate from the tolerance range are detected within the predetermined rotation angle (RB) range, the control device 40 determines that a rotational abnormality of the wafer W has occurred and issues an alarm. The predetermined rotation angle (RB) can be set arbitrarily. For example, a predetermined rotation angle (RB) can be set between the rotations R2 and R3 before and after the rotation R1 in which the transmitted waveform Pk2 is generated. This configuration prevents the transmitted waveform Pk2 measured when the notch passes through the movable axis 13b from being misinterpreted as an abnormality in the rotation of the wafer W.

[0114] The embodiments described above are intended to enable persons with ordinary skill in the art to implement the present invention. Various modifications of the above embodiments can be made naturally by those skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments as well. Therefore, the present invention is not limited to the embodiments described, but is to be interpreted in the broadest sense according to the technical idea defined by the claims. [Explanation of Symbols]

[0115] 1. The first side 2. The second side 10 Substrate holding device 11a, 11b Laura 13a,13b Eccentric shaft 14a, 14b First shaft section 15a,15b 2nd shaft part 16a,16b Intermediate shaft part 17a, 17b Counterweights 18 Actuators 19 battalions 20 base plates 21 Movable platform 23 Connecting member 24 bearings 26 Linear motion guide 27a,27b Motor support 28a, 28b coupling 29a,29b Electric motor 31a, 31b Wafer holding surface (substrate holding surface) 40 Control device 51 Piston 52a, 52b Housing 53a, 53b Housing body 54a,54b Lid 55a,55b septum membrane 57a, 57b Pressure chamber 59a, 59b Compressed gas flow path 62a, 62b Pressure regulator 63a, 63b Switching valve 64 Compressed gas supply source 71a,71b central part 72a,72b Inner wall 73a, 73b Folded section 74a,74b External wall part 75a,75b Thick part 77 Notch detection sensor 80 Distance Sensor 81 Magnets 84 Sensor Heads 85 Focusing lens 88 Sensor Targets 92A Floodlight Fiber Optic Cable 92B Optical fiber receiving cable 93 Amplifier 93a light source 93b Light intensity measuring device 94 Distance Calculator 100 Substrate Processing Equipment 200 processing heads 201 Processing Tools

Claims

1. Three or more rollers, fixed to three or more eccentric shafts, each comprising at least one reference shaft and at least one movable shaft displaceable toward and toward the at least one reference shaft, are brought into contact with the peripheral edge of a substrate having a notch, wherein each of the eccentric shafts has a first shaft portion connected to an electric motor and a second shaft portion eccentric to the first shaft portion and to which the rollers are fixed. By rotating the first shaft portion of the three or more eccentric shafts around their respective axes, the three or more rollers are made to move in a circular motion, thereby rotating the substrate around its axis and causing the substrate to move in a circular motion. The processing tool is brought into contact with the rotating and circularly moving substrate to process the substrate. During the processing of the substrate, the control device calculates the rotational speed of the substrate based on the measurement value of the notch detection sensor, which detects when the notch has passed the movable axis. A substrate processing method wherein, if the calculated rotational speed of the substrate deviates from the allowable range set for the theoretical rotational speed of the substrate, the control device issues an alarm.

2. The substrate processing method according to claim 1, further comprising the step of performing additional processing on the substrate based on the difference or ratio between the rotation speed of the substrate and the theoretical rotation speed when the calculated rotation speed of the substrate falls below the lower limit of the allowable range.

3. The substrate processing method according to claim 1 or 2, wherein the notch detection sensor is an acceleration sensor that measures the acceleration generated when the movable axis moves toward and toward the reference axis.

4. The substrate processing method according to claim 1 or 2, wherein the notch detection sensor is a distance sensor that measures the distance traveled by the movable axis when the movable axis moves toward and toward the reference axis.

5. Three or more rollers, fixed to three or more eccentric shafts, each comprising at least one reference shaft and at least one movable shaft displaceable toward and toward the at least one reference shaft, are brought into contact with the peripheral edge of a substrate having a notch, wherein each of the eccentric shafts has a first shaft portion connected to an electric motor and a second shaft portion eccentric to the first shaft portion and to which the rollers are fixed. By rotating the first shaft portion of the three or more eccentric shafts around their respective axes, the three or more rollers are made to move in a circular motion, thereby rotating the substrate around its axis and causing the substrate to move in a circular motion. The processing tool is brought into contact with the rotating and circularly moving substrate to process the substrate. During the processing of the substrate, the distance traveled by the movable axis is measured by a distance sensor, and the passage of the notch through the movable axis is detected by a notch detection sensor. The control device issues an alarm if the measurement value of the distance sensor deviates from a predetermined tolerance range and the notch detection sensor does not detect the notch. A substrate processing method wherein, when the notch detection sensor detects the notch, the control device does not issue an alarm even if the measurement value of the distance sensor deviates from the predetermined allowable range.

6. The substrate processing method according to claim 5, wherein, during the predetermined rotation angle of the roller before and after the notch detection point of the notch detection sensor, the alarm is canceled even if the measurement value of the distance sensor deviates from a predetermined allowable range.

7. Three or more rollers, fixed to three or more eccentric shafts, each comprising at least one reference shaft and at least one movable shaft displaceable toward and toward the at least one reference shaft, are brought into contact with the peripheral edge of a substrate having a notch, wherein each of the eccentric shafts has a first shaft portion connected to an electric motor and a second shaft portion eccentric to the first shaft portion and to which the rollers are fixed. By rotating the first shaft portion of the three or more eccentric shafts around their respective axes, the three or more rollers are made to move in a circular motion, thereby rotating the substrate around its axis and causing the substrate to move in a circular motion. The processing tool is brought into contact with the rotating and circularly moving substrate to process the substrate. During the processing of the substrate, the distance traveled by the movable axis is measured by a distance sensor, and the distance sensor is used to detect when the notch has passed the movable axis. The control device issues an alarm if the measurement value of the distance sensor deviates from a predetermined tolerance range and the distance sensor does not detect the notch. A substrate processing method wherein, when the control device detects the notch, the control device does not issue an alarm even if the measurement value of the distance sensor deviates from the predetermined tolerance range.

8. The substrate processing method according to claim 7, wherein, during a predetermined rotation angle of the roller before and after the detection of the notch of the distance sensor, the alarm is canceled even if the measurement value of the distance sensor deviates from a predetermined allowable range.

9. A three or more eccentric shafts, each having a first shaft portion and a second shaft portion eccentric to the first shaft portion, including at least one reference shaft and at least one movable shaft, Three or more rollers fixed to the second axis portion of the three or more eccentric shafts and capable of contacting the peripheral edge of a substrate having a notch, Three or more electric motors rotate the first shaft portion of the three or more eccentric shafts around their respective axes, causing the three or more rollers to move in a circular motion, thereby rotating the substrate around its axis and causing the substrate to move in a circular motion. An actuator that displaces the at least one movable axis in a direction toward and away from the at least one reference axis, A processing tool that contacts the surface of the rotating and circularly moving substrate and processes the surface of the substrate, A notch detection sensor that detects when the notch has passed the movable axis, The system comprises a control device to which the notch detection sensor is connected, The control device is During the processing of the substrate, the rotation speed of the substrate is calculated based on the measurement value of the notch detection sensor. A substrate processing device that issues an alarm if the calculated rotational speed of the substrate deviates from the allowable range set for the theoretical rotational speed of the substrate.

10. The substrate processing apparatus according to claim 9, wherein the control device performs additional processing on the substrate based on the difference or ratio between the rotation speed of the substrate and the theoretical rotation speed when the calculated rotation speed of the substrate falls below the lower limit of the allowable range.

11. The substrate processing apparatus according to claim 9 or 10, wherein the notch detection sensor is an acceleration sensor that measures the acceleration generated when the movable axis moves toward and toward the reference axis.

12. The substrate processing apparatus according to claim 9 or 10, wherein the notch detection sensor is a distance sensor that measures the distance traveled by the movable axis when the movable axis moves toward and toward the reference axis.

13. A three or more eccentric shafts, each having a first shaft portion and a second shaft portion eccentric to the first shaft portion, including at least one reference shaft and at least one movable shaft, Three or more rollers fixed to the second axis portion of the three or more eccentric shafts and capable of contacting the peripheral edge of a substrate having a notch, Three or more electric motors rotate the first shaft portion of the three or more eccentric shafts around their respective axes, causing the three or more rollers to move in a circular motion, thereby rotating the substrate around its axis and causing the substrate to move in a circular motion. An actuator that displaces the at least one movable axis in a direction toward and away from the at least one reference axis, A processing tool that contacts the surface of the rotating and circularly moving substrate and processes the surface of the substrate, A notch detection sensor that detects when the notch has passed the movable axis, A distance sensor that measures the distance traveled by the movable axis when it moves toward and toward the reference axis, The system comprises a control device to which the notch detection sensor and the distance sensor are connected, The control device is If, during processing of the substrate, the measurement value of the distance sensor deviates from a predetermined tolerance range and the notch detection sensor does not detect the notch, an alarm is issued. During the processing of the substrate, A substrate processing apparatus that, when the notch detection sensor detects the notch, does not issue an alarm even if the measurement value of the distance sensor deviates from the predetermined tolerance range.

14. The substrate processing apparatus according to claim 13, wherein the control device cancels the alarm even if the measurement value of the distance sensor deviates from a predetermined allowable range during a predetermined rotation angle of the roller before and after the notch detection sensor detects the notch.

15. A three or more eccentric shafts, each having a first shaft portion and a second shaft portion eccentric to the first shaft portion, including at least one reference shaft and at least one movable shaft, Three or more rollers fixed to the second axis portion of the three or more eccentric shafts and capable of contacting the peripheral edge of a substrate having a notch, Three or more electric motors rotate the first shaft portion of the three or more eccentric shafts around their respective axes, causing the three or more rollers to move in a circular motion, thereby rotating the substrate around its axis and causing the substrate to move in a circular motion. An actuator that displaces the at least one movable axis in a direction toward and away from the at least one reference axis, A processing tool that contacts the surface of the rotating and circularly moving substrate and processes the surface of the substrate, A distance sensor measures the distance the movable axis moves when it moves toward and away from the reference axis, and detects when the notch has passed the movable axis. The system comprises a control device to which the distance sensor is connected, The control device is During the processing of the substrate, if the measurement value of the distance sensor deviates from a predetermined tolerance range and the distance sensor does not detect the notch, an alarm is issued. A substrate processing apparatus that, when the distance sensor detects the notch during the processing of the substrate, does not issue an alarm even if the measurement value of the distance sensor deviates from the predetermined tolerance range.

16. The substrate processing apparatus according to claim 15, wherein the control device cancels the alarm even if the measurement value of the distance sensor deviates from a predetermined allowable range during a predetermined rotation angle of the roller before and after the detection of the notch of the distance sensor.

Images