Substrate holding device and substrate processing device

Abstract

To provide a substrate holding apparatus that can stably hold a substrate such as a wafer in a circular motion while rotating the substrate around its axis center.SOLUTION: A substrate holding apparatus 10 has a plurality of rollers 11a, 11b, a plurality of electric motors 29a, 29b for rotating the plurality of rollers 11a, 11b, a plurality of eccentric axes 13a, 13b arranged around a central axis CP, and an actuator 18. The plurality of eccentric axes 13a, 13b includes one movable shaft 13b and a plurality of reference shafts 13a, and the actuator 18 is connected to the one movable shaft 13b via one movable platform 21.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a substrate holding device that holds and rotates a substrate such as a wafer, and also to a substrate processing apparatus including such a substrate holding device. [Background technology]

[0002] In recent years, devices such as memory circuits, logic circuits, and image sensors (e.g., CMOS sensors) are becoming more highly integrated. In the processes for forming these devices, foreign matter such as fine particles and dust may adhere to the devices. Foreign matter that adheres to the devices may cause short circuits between wiring and circuit malfunctions. Therefore, in order to improve the reliability of the devices, it is necessary to clean the wafers on which the devices are formed and remove the foreign matter on the wafer.

[0003] Foreign matter such as fine particles and dust as mentioned above may also adhere to the back surface (bare silicon surface) of the wafer. If such foreign matter adheres to the back surface of the wafer, the wafer may move away from the stage reference surface of the exposure tool or the wafer front surface may tilt relative to the stage reference surface, resulting in deviations in patterning and focal length. To prevent such problems, it is necessary to remove the foreign matter adhered to the back surface of the wafer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-83224 A Summary of the Invention [Problem to be solved by the invention]

[0005] Recently, there has been an increasing demand for devices that can process the entire surface of a substrate more efficiently.To address this, a substrate holding device has been proposed in which the peripheral portion of a 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 (for example, Patent Document 1).

[0006] In a substrate processing apparatus using such a substrate holding device, the processing tool can process the entire surface of the substrate, including the outermost part, without the rollers coming into contact with the processing tool. Also, the combination of such a circular motion and the rotation around the axis of the substrate can increase the speed at each point on the surface of the substrate, thereby improving the efficiency of substrate processing.

[0007] In such a substrate holding device, it is necessary to align the phases of the multiple eccentric shafts with each other. However, it is difficult to accurately align the phases of the multiple eccentric shafts, and vibrations may occur in the eccentric shafts during rotation of the substrate due to phase misalignment. When vibrations occur in one of the multiple eccentric shafts, the vibrations are propagated to the other eccentric shafts via a common support plate that supports these eccentric shafts, which may cause unstable holding of the substrate.

[0008] Therefore, an object of the present invention is to provide a substrate holding device capable of stably holding a substrate such as a wafer while causing the substrate to make a circular motion and rotating the substrate about its axis, and to provide a substrate processing apparatus for processing the surface of the substrate using such a substrate holding device. [Means for solving the problem]

[0009] In one embodiment, a substrate holding device that rotates a substrate around its axis while causing the substrate to move in a circular motion includes a plurality of rollers that can contact a peripheral portion of the substrate, a plurality of electric motors that rotate the plurality of rollers, a plurality of eccentric shafts arranged around a predetermined central axis, an actuator having a piston, and a single movable base connected to the piston, the plurality of eccentric shafts having a plurality of first shaft portions and a plurality of second shaft portions that are each eccentric from the plurality of first shaft portions, the plurality of rollers are fixed to the plurality of second shaft portions, the plurality of first shaft portions are each connected to the plurality of electric motors, and the plurality of eccentric shafts are each connected to a single movable base. A substrate holding device is provided, the substrate holding device including one movable shaft and a plurality of reference shafts, the one movable base having a bearing for rotatably supporting the one movable shaft and a connecting member fixed to the piston, the actuator being connected to the one movable shaft via the one movable base, the actuator being configured to move the one movable shaft and the one movable base together in a direction toward the plurality of reference shafts and in a direction away from the plurality of reference shafts, the actuator including a piston, a housing positioned away from the piston, and a partition membrane forming a pressure chamber between the piston and the housing.

[0010] In one aspect, a substrate holding device is provided that rotates a substrate about its axis while causing the substrate to move in a circular motion, the substrate holding device comprising: a plurality of rollers capable of contacting a peripheral portion of the substrate; a plurality of electric motors that rotate the plurality of rollers; a plurality of eccentric shafts arranged around a predetermined central axis; and a plurality of actuators, the plurality of eccentric shafts having a plurality of first shaft portions and a plurality of second shaft portions that are each eccentric from the plurality of first shaft portions, the plurality of rollers are each fixed to the plurality of second shaft portions, the plurality of first shaft portions are each connected to the plurality of electric motors, the plurality of eccentric shafts are composed of a plurality of movable shafts and a plurality of reference shafts, the plurality of actuators are each connected to the plurality of movable shafts, and the plurality of actuators are configured to move the plurality of movable shafts in directions toward and away from the plurality of reference shafts.

[0011] In one embodiment, the multiple eccentric shafts further have multiple intermediate shaft portions connecting the multiple first shaft portions and the multiple second shaft portions, the multiple first shaft portions being fixed to the multiple intermediate shaft portions respectively, and the multiple second shaft portions being fixed to the multiple intermediate shaft portions respectively. In one embodiment, the substrate holding device further includes an operation control unit that rotates the multiple electric motors at the same speed and in the same phase. In one aspect, the directions toward and away from the plurality of reference axes are directions toward and away from the central axis. In one aspect, each of the plurality of actuators includes a piston, a housing spaced apart from the piston, and a partition membrane that forms a pressure chamber between the piston and the housing. In one aspect, the partition membrane has a central portion that contacts the end of the piston, an inner wall portion connected to the central portion and extending along the side of the piston, a folded portion connected to the inner wall portion and having a curved cross-section, and an outer wall portion connected to the folded portion and positioned outside the inner wall portion. In one embodiment, the substrate support device further comprises at least one non-contact distance sensor that measures a distance traveled by at least one of the plurality of movable axes. In one embodiment, the substrate holding device further includes an operation control unit configured to determine whether or not an abnormality has occurred in the substrate holding device by comparing the measured value of the travel distance or an index value calculated from multiple measured values ​​of the travel distance with a preset threshold value. In one embodiment, the index value is an average value of the position of at least one of the plurality of movable shafts as the plurality of rollers rotate through one or more revolutions. In one embodiment, the index value is a difference between a maximum value and a minimum value of a position of at least one of the plurality of movable shafts while the plurality of rollers rotates one or more revolutions.

[0012] In one aspect, a substrate holding device is provided that rotates a substrate about its axis while causing the substrate to move in a circular motion, the substrate holding device comprising: a plurality of rollers capable of contacting a peripheral portion of the substrate; a plurality of electric motors that rotate the plurality of rollers; a plurality of eccentric shafts arranged around a predetermined central axis; and an actuator, the plurality of eccentric shafts having a plurality of first shaft portions and a plurality of second shaft portions each eccentric from the plurality of first shaft portions, the plurality of rollers being fixed to the plurality of second shaft portions respectively, the plurality of first shaft portions being connected to the plurality of electric motors respectively, the plurality of eccentric shafts being composed of a movable shaft and a plurality of reference shafts, the actuator being connected to the movable shaft, the actuator being configured to move the movable shaft in a direction toward the plurality of reference shafts and in a direction away from the plurality of reference shafts, the actuator comprising a piston, a housing positioned away from the piston, and a partition membrane that forms a pressure chamber between the piston and the housing.

[0013] In one embodiment, the multiple eccentric shafts further have multiple intermediate shaft portions connecting the multiple first shaft portions and the multiple second shaft portions, the multiple first shaft portions being fixed to the multiple intermediate shaft portions respectively, and the multiple second shaft portions being fixed to the multiple intermediate shaft portions respectively. In one embodiment, the substrate holding device further includes an operation control unit that rotates the multiple electric motors at the same speed and in the same phase. In one aspect, the directions toward and away from the plurality of reference axes are directions toward and away from the central axis. In one aspect, the partition membrane has a central portion that contacts the end of the piston, an inner wall portion connected to the central portion and extending along the side of the piston, a folded portion connected to the inner wall portion and having a curved cross-section, and an outer wall portion connected to the folded portion and positioned outside the inner wall portion. In one embodiment, the substrate holding device further includes a non-contact distance sensor that measures the moving distance of the movable shaft. In one embodiment, the substrate holding device further includes an operation control unit configured to determine whether or not an abnormality has occurred in the substrate holding device by comparing the measured value of the travel distance or an index value calculated from multiple measured values ​​of the travel distance with a preset threshold value. In one embodiment, the index value is an average value of the positions of the movable shaft when the rollers rotate one or more revolutions. In one embodiment, the index value is a difference between a maximum value and a minimum value of the position of the movable shaft while the plurality of rollers rotate one or more revolutions.

[0014] In one aspect, there is provided a substrate processing apparatus including the substrate holding device described above, and a processing head that brings a processing tool into contact with a first surface of a substrate to process the first surface. Effect of the Invention

[0015] According to the present invention, the multiple movable shafts are respectively connected to the multiple actuators and are not supported by a common support plate. With this configuration, even if vibration occurs in one movable shaft while the substrate is rotating, the vibration can be prevented from being transmitted to the other movable shafts. As a result, the substrate holding device can stably hold the substrate.

[0016] Furthermore, according to the present invention, since the housing of the actuator is disposed away from the piston, no sliding resistance occurs between the piston and the housing, and as a result, the substrate holding device can stably hold the substrate without applying an excessive load to the substrate. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a plan view illustrating an embodiment of a substrate holding device. [Diagram 2] 2 is a side view of the substrate holding device shown in FIG. [Diagram 3] 2 is a bottom view of the substrate holding device shown in FIG. [Figure 4] 4(a) to 4(d) are schematic diagrams illustrating the operation of the substrate holding device receiving a wafer. [Diagram 5] FIG. 2 is a schematic diagram illustrating an embodiment of an actuator. [Figure 6] FIG. 2 is a cross-sectional view showing a schematic diagram of one embodiment of a partition membrane. [Figure 7] FIG. 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 FIG. 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] 13 is a diagram showing an example of the position of a movable axis when an abnormality in wafer rotation occurs; FIG. [Figure 9] 13A and 13B are diagrams illustrating another example of the position of the movable axis when an abnormality in wafer rotation occurs. [Figure 10] FIG. 13 is a schematic diagram showing another embodiment of the distance sensor. [Figure 11] FIG. 11 is a plan view that illustrates a schematic diagram of an embodiment of a substrate processing apparatus including a substrate holding device described with reference to FIGS. 1 to 10. [Figure 12] 12 is a side view of the substrate holding device shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing an embodiment of a substrate holding device, FIG. 2 is a side view of the substrate holding device shown in FIG. 1, and FIG. 3 is a bottom view of the substrate holding device shown in FIG. 1. The substrate holding device of this embodiment is configured to hold a wafer W, which is an example of a substrate, while circularly moving the wafer W and rotating the wafer W around its axis. The substrate holding device 10 includes a plurality of rollers 11a, 11b that can contact the peripheral portion 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 an operation control unit 40 that rotates the plurality of electric motors 29a, 29b at the same speed and in the same phase.

[0019] The operation control unit 40 is composed of at least one computer. The operation control unit 40 includes a storage device 40a and an arithmetic device 40b. The arithmetic device 40b includes a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit) that performs calculations according to instructions included in a program stored in the storage device 40a. The storage device 40a includes a main storage device (e.g., random access memory) that can be accessed by the arithmetic device 40b, and an auxiliary storage device (e.g., a hard disk drive or a solid state drive) that stores data and programs.

[0020] Roller 11a has a wafer holding surface (substrate holding surface) 31a that holds the peripheral portion of wafer W, and roller 11b has a wafer holding surface (substrate holding surface) 31b that holds the peripheral portion of wafer W. Roller 11a and roller 11b have the same configuration and size. The multiple eccentric shafts 13a, 13b are arranged around a predetermined central axis CP of substrate holding device 10.

[0021] 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.

[0022] Each of the multiple eccentric shafts 13a has a first shaft portion 14a, a second shaft portion 15a eccentric from 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 integral structures. For example, the first shaft portion 14a and the intermediate shaft portion 16a may be integral structures. In another example, the entire first shaft portion 14a, the second shaft portion 15a, and the intermediate shaft portion 16a may be integral structures. Although each eccentric shaft 13a shown in FIG. 2 has a 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 from the first shaft portion 14a by a predetermined distance.

[0023] The rollers 11a are fixed to one ends of the second shaft portions 15a, respectively, and the other ends of the second shaft portions 15a are fixed to the intermediate shaft portions 16a, respectively. The first shaft portions 14a are connected to the electric motors 29a via the couplings 28a, respectively, and the other ends of the first shaft portions 14a are fixed to the intermediate shaft portions 16a, respectively.

[0024] Each of the multiple eccentric shafts 13b has a first shaft portion 14b, a second shaft portion 15b eccentric from 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 integral structures. For example, the first shaft portion 14b and the intermediate shaft portion 16b may be integral structures. In another example, the entire first shaft portion 14b, the second shaft portion 15b, and the intermediate shaft portion 16b may be integral structures. Although each eccentric shaft 13b shown in FIG. 2 has a 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 from the first shaft portion 14b by a predetermined distance.

[0025] The rollers 11b are fixed to one ends of the second shaft portions 15b, respectively, and the other ends of the second shaft portions 15b are fixed to the intermediate shaft portions 16b, respectively. The first shaft portions 14b are connected to the electric motors 29b via the couplings 28b, respectively, and the other ends of the first shaft portions 14b are fixed to the intermediate shaft portions 16b, respectively.

[0026] The electric motor 29a is configured to rotate the eccentric shaft 13a about the first shaft portion 14a, and the electric motor 29b is configured to rotate the eccentric shaft 13b about the first shaft portion 14b. The electric motors 29a and 29b are connected to an operation control unit 40.

[0027] The second shaft portion 15a of the eccentric shaft 13a is eccentric from the first shaft portion 14a by a distance e. Therefore, when the electric motor 29a is operated, the roller 11a performs a circular motion of a radius e while rotating around the second shaft portion 15a. The axis of the roller 11a coincides with the axis of the second shaft portion 15a. That is, the roller 11a performs a circular motion of a radius e around the axis of the first shaft portion 14a while rotating around its axis. When the roller 11a rotates once around the axis of the first shaft portion 14a, the roller 11a rotates once around the axis of the roller 11a.

[0028] Similarly, the second shaft portion 15b of the eccentric shaft 13b is eccentric from the first shaft portion 14b by a distance e. Therefore, when the electric motor 29b is operated, the roller 11b performs a circular motion of a radius e while rotating around the second shaft portion 15b. The axis of the roller 11b coincides with the axis of the second shaft portion 15b. That is, the roller 11b performs a circular motion of a radius e around the axis of the first shaft portion 14b while rotating around its axis. When the roller 11b rotates once around the axis of the first shaft portion 14b, the roller 11b rotates once around the axis of the roller 11b. In this specification, the circular motion is defined as the motion of an object moving on a circular orbit.

[0029] The operation of the electric motors 29a, 29b is controlled by the operation control unit 40. As described above, the operation control unit 40 rotates all of the electric motors 29a, 29b at the same speed and in the same phase. More specifically, the operation control unit 40 issues commands to the electric motors 29a, 29b to start all of the electric motors 29a, 29b at the same timing and to rotate all of the electric motors 29a, 29b in the same direction. Furthermore, the operation control unit 40 synchronizes the rotation speeds and phases of the electric motors 29a, 29b during their operation.

[0030] As a result, all of the eccentric shafts 13a, 13b rotate in the same direction, at the same rotational speed, and in the same phase around the axis of the first shaft portions 14a, 14b. All of the rollers 11a, 11b perform circular motion around the axis of the first shaft portions 14a, 14b while rotating in the same direction, at the same rotational speed, and in the same phase around their axes. Therefore, when the wafer W is held by the rollers 11a, 11b, the operation control portion 40 operates the electric motors 29a, 29b, so that the wafer W performs circular motion of radius e while rotating around its axis.

[0031] In this way, the substrate holding device 10 can rotate the wafer W about its axis while causing the wafer W to move in a circular motion with a simple structure. The combination of such a circular motion and the rotation about 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 described below is pressed against the surface of the wafer W, the relative speed between the processing head and the surface of the wafer W increases, and the processing rate of the wafer W can be improved.

[0032] Counterweights 17a and 17b are fixed to the multiple eccentric shafts 13a and 13b, respectively. More specifically, the counterweights 17a and 17b are fixed to the intermediate shafts 16a and 16b, respectively. The counterweight 17a and the roller 11a are disposed symmetrically with respect to the first shaft portion 14a. The weight of the counterweight 17a is a weight that is generated by the centrifugal force acting on the counterweight 17a when the eccentric shaft 13a rotates around the first shaft portion 14a, and that is generated in the radial direction from the first shaft portion 14a toward the roller 11a.

[0033] Similarly, the counterweight 17b and the roller 11b are disposed symmetrically with respect to the first shaft portion 14b. The weight of the counterweight 17b is such that when the eccentric shaft 13b rotates around the first shaft portion 14b, the centrifugal force generated in the radial direction from the first shaft portion 14b toward the roller 11b is cancelled by the centrifugal force acting on the counterweight 17b. Such counterweights 17a, 17b can prevent the vibration of the eccentric shafts 13a, 13b caused by the imbalance of weight when the eccentric shafts 13a, 13b rotate.

[0034] The substrate holding device 10 further includes a base plate 20, a plurality of linear guides 26 fixed to the lower surface of the base plate 20, a plurality of movable tables 21 supported by the plurality of linear guides 26, and a plurality of actuators 18 connected to the plurality of movable tables 21. The linear guides 26 limit the movement of the movable tables 21 to linear movement in a direction parallel to the lower surface of the base plate 20.

[0035] Each movable base 21 has a bearing 24 that rotatably supports the eccentric shaft 13b, and a connecting member 23 connected to the actuator 18. The multiple actuators 18 are connected to the multiple eccentric shafts 13b via the multiple movable bases 21. The multiple movable bases 21, each including the multiple bearings 24, are moved independently by the multiple actuators 18 together with the multiple eccentric shafts 13b.

[0036] The actuators 18 are fixed to the lower surface of the base plate 20. The operation of the actuators 18 is controlled by an operation control unit 40. The operation control unit 40 can operate the actuators 18 independently. The actuators 18 are configured to move the movable base 21 in parallel with the base plate 20.

[0037] The eccentric shaft 13a extends through the base plate 20. The roller 11a is disposed above the base plate 20, and the electric motor 29a is disposed below the base plate 20. The eccentric shaft 13a is rotatably supported by a bearing 19 held by the base plate 20. The positions of the eccentric shaft 13a are 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.

[0038] The eccentric shaft 13b extends through the movable base 21 and the base plate 20. The roller 11b is disposed above the base plate 20, and the electric motor 29b is disposed 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 lower surface of the movable base 21, and the electric motor 29b is fixed to the electric motor support 27b.

[0039] According to the above-mentioned 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 the 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.

[0040] The actuator 18 can move the movable shafts 13b in parallel with 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 approaching the multiple reference shafts 13a and in a direction away from the multiple reference shafts 13a. When the two movable shafts 13b move in a direction approaching the two reference shafts 13a, the wafer W is held by the two rollers 11a and the two rollers 11b. When the two movable shafts 13b move in a direction away from the two reference shafts 13a, the wafer W is released from the two rollers 11a and the two rollers 11b.

[0041] As shown in FIG. 3, in this embodiment, the actuator 18 and the linear guide 26 are arranged to face 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 FIG. 3. In this embodiment, the direction toward the multiple reference axes 13a and the direction away from the multiple 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 in the direction 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 a minimum force. In one embodiment, each of the multiple actuators 18 and the multiple linear guides 26 may be arranged to face each of the multiple reference axes 13a.

[0042] 4(a) to 4(d) are schematic diagrams illustrating the operation of the substrate holding device 10 to receive the wafer W. As shown in Fig. 4(a), before receiving the wafer W, the actuators 18 (see Figs. 2 and 3) are actuated to move the rollers 11b in a direction away from the central axis CP. At this time, the rollers 11a and 11b are eccentric outward.

[0043] Next, as shown in Fig. 4(b), the wafer W is transported to the substrate holding device 10 by a transport device (not shown). Furthermore, as shown in Fig. 4(c), with the wafer W positioned between the rollers 11a and 11b, the reference shaft 13a is rotated 180 degrees to make each roller 11a eccentric inward. Then, as shown in Fig. 4(d), the actuators 18 are operated to move each roller 11b and each movable shaft 13b in a direction approaching each reference shaft 13a until each roller 11b contacts the wafer W.

[0044] In this manner, the peripheral portion of the wafer W is held by the wafer holding surface 31a of the roller 11a and the wafer holding surface 31b of the roller 11b. When the wafer W is removed from the substrate holding device 10, the steps shown in Figures 4(a) to 4(d) are carried out in reverse order.

[0045] In a conventional substrate holding device (see, for example, Patent Document 1), multiple movable shafts are supported by one support plate, and a single actuator connected to the support plate moves the multiple movable shafts together with the support plate to hold the substrate. With this configuration, if vibration occurs in one of the multiple movable shafts due to a phase shift between the multiple eccentric shafts, the vibration propagates to the other movable shafts, making the substrate unstable.

[0046] In contrast, in the above-described embodiment, the two movable shafts 13b are supported by two movable tables 21, respectively, and further connected to two actuators 18, respectively. With this configuration, even if vibration occurs in one movable shaft 13b while the wafer W is rotating, the vibration can be prevented from being propagated to the other movable shaft 13b. As a result, the substrate holding device 10 can stably hold the wafer W.

[0047] 5 is a schematic diagram showing one embodiment of the actuator 18. Each actuator 18 includes a piston 51 arranged in the longitudinal direction of the actuator 18, housings 52a, 52b arranged outside the piston 51, and partition membranes (diaphragms) 55a, 55b forming pressure chambers 57a, 57b between the piston 51 and the housings 52a, 52b. The piston 51 is movable in the direction indicated by the arrow in FIG. 5 (the longitudinal direction of the actuator 18). The housings 52a, 52b are arranged away from the piston 51. The housing 52a is arranged so as to surround one end of the piston 51, and the housing 52b is arranged so as to surround the other end of the piston 51.

[0048] 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 FIG. 5. More specifically, the movable base 21 is configured to be movable together with the piston 51 in a direction approaching the reference axis 13a and a direction away from the reference axis 13a. In this embodiment, the actuator 18 is disposed facing the central axis CP of the substrate holding device 10 (see FIG. 3), and therefore the movement directions of the piston 51 and the movable base 21 are a direction toward the central axis CP and a direction away from the central axis CP.

[0049] The housings 52a, 52b include housing bodies 53a, 53b arranged to surround the side surfaces of the piston 51, and lids 54a, 54b fixed to the housing bodies 53a, 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.

[0050] The pressure chamber 57a is formed by the partition wall film 55a and the inner surface of the housing 52a. Similarly, the pressure chamber 57b is formed by the partition wall film 55b and the inner surface of the housing 52b. More specifically, the pressure chamber 57a is formed by the partition wall film 55a and the inner surface of the lid 54a, and the pressure chamber 57b is formed by the partition wall film 55b and the inner surface of the lid 54b. The partition wall films 55a and 55b have the same configuration. In this embodiment, the housings 52a and 52b have the same configuration, but may have different configurations.

[0051] The lids 54a and 54b of the housings 52a and 52b are formed with compressed gas flow paths 59a and 59b. The compressed gas flow paths 59a and 59b are connected to a compressed gas supply source 64 via pressure regulators 62a and 62b and switching valves 63a and 63b. The pressure chambers 57a and 57b are in communication with the pressure regulators 62a and 62b through the compressed gas flow paths 59a and 59b.

[0052] When moving the piston 51, the switching valves 63a, 63b are operated to connect the pressure chambers 57a, 57b to the compressed gas supply source 64. In this embodiment, the switching valves 63a, 63b are connected to the operation control unit 40. The switching valves 63a, 63b are valves that selectively connect the pressure chambers 57a, 57b to the compressed gas supply source 64 or the atmosphere. Three-way valves can be used as the switching valves 63a, 63b.

[0053] Compressed gas such as compressed air is supplied to the pressure chambers 57a, 57b from a compressed gas supply source 64 through compressed gas flow paths 59a, 59b. Examples of the compressed gas supply source 64 include a pump or a compressed gas supply line as a utility that is pre-installed in a factory. The pressure of the compressed gas in the pressure chambers 57a, 57b is controlled by pressure regulators 62a, 62b. In this embodiment, the pressure regulators 62a, 62b are electropneumatic regulators. The pressure regulators 62a, 62b in this embodiment are connected to the operation control unit 40. In one embodiment, the pressure regulators 62a, 62b may be manually operated pressure regulators. In this case, the pressure regulators 62a, 62b are not connected to the operation control unit 40.

[0054] The operation control unit 40 transmits a predetermined set pressure value to the pressure regulators 62a, 62b, and the pressure regulators 62a, 62b are configured to control the pressure of the compressed gas in the pressure chambers 57a, 57b according to the set pressure value. Examples of such pressure regulators 62a, 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 operation control unit 40.

[0055] Piston 51 moves according to the difference between the pressure in pressure chamber 57a and the pressure in pressure chamber 57b. When the pressure in pressure chamber 57a is made higher than the pressure in pressure chamber 57b, piston 51 moves in a direction away from reference axis 13a (see FIG. 3). When the pressure in pressure chamber 57b is made higher than the pressure in pressure chamber 57a, piston 51 moves in a direction toward reference axis 13a (see FIG. 3).

[0056] In this embodiment, when the piston 51 is moved, compressed gas is introduced into both the 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 of the pressure chambers 57a and 57b. 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.

[0057] 6 is a cross-sectional view showing an embodiment of the partition membranes 55a and 55b. The partition membrane 55a has a central portion 71a that contacts one end of the piston 51, an inner wall portion 72a that is connected to the central portion 71a and extends along the side surface of the piston 51, a folded portion 73a that is connected to the inner wall portion 72a and has a curved cross section, and an outer wall portion 74a that is connected to the folded portion 73a and is located outside the inner wall portion 72a. The partition membrane 55a contacts 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 main body 53a.

[0058] 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 disposed so as to surround the inner wall portion 72a.

[0059] Similarly, the partition membrane 55b has a central portion 71b that contacts the other end of the piston 51, an inner wall portion 72b that is connected to the central portion 71b and extends along the side surface of the piston 51, a folded portion 73b that is connected to the inner wall portion 72b and has a curved cross section, and an outer wall portion 74b that is connected to the folded portion 73b and is located outside the inner wall portion 72b. The partition membrane 55b contacts 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 main body 53b.

[0060] 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 disposed so as to surround the inner wall portion 72b.

[0061] The partition membranes 55a and 55b are in contact with the piston 51 but are not fixed to the piston 51. A thick portion 75a forming the edge of the partition membrane 55a is sandwiched between the housing body 53a and the lid 54a. Similarly, a thick portion 75b forming 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 made of a flexible material. Examples of materials forming 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.

[0062] FIG. 7(a) is a diagram showing the state of 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 FIG. 7(b) is a diagram showing the state of actuator 18 when the pressure in pressure chamber 57b is higher than the pressure in pressure chamber 57a.

[0063] As shown in FIG. 7(a), when the pressure in the pressure chamber 57a becomes higher than the pressure in the pressure chamber 57b, a force toward the pressure chamber 57b is applied to the piston 51. As a result, the partition membranes 55a and 55b deform, and the piston 51, the movable base 21, and the movable shaft 13b move together in a direction away from the reference axis 13a (see FIG. 3). At this time, while the folded portion 73a maintains its shape, a part of the inner wall portion 72a becomes a part of the folded portion 73a, and a part of the folded portion 73a becomes a part of the outer wall portion 74a. At the same time, while the folded portion 73b maintains its shape, a part of the outer wall portion 74b becomes a part of the folded portion 73b, and a part of the folded portion 73b becomes a part of the inner wall portion 72b.

[0064] As shown in FIG. 7(b), when the pressure in the pressure chamber 57b becomes higher than the pressure in the pressure chamber 57a, a force toward the pressure chamber 57a is applied to the piston 51. As a result, the partition membrane 55b deforms, and the piston 51, the movable base 21, and the movable shaft 13b move together in a direction approaching the reference shaft 13a (see FIG. 3). At this time, while the folded portion 73b maintains its shape, a part of the inner wall portion 72b becomes a part of the folded portion 73b, and a part of the folded portion 73b becomes a part of the outer wall portion 74b. At the same time, while the folded portion 73a maintains its shape, a part of the outer wall portion 74a becomes a part of the folded portion 73a, and a part of the folded portion 73a becomes a part of the inner wall portion 72a.

[0065] Due to such movement of the partition membranes 55a, 55b, the piston 51 can move smoothly without receiving almost any reaction force from the partition membranes 55a, 55b. If the piston and the housing are in contact with each other as in a normal air cylinder, sliding resistance occurs between the piston and the housing when vibration occurs during the rotation of the wafer. Such sliding resistance applies an excessive load to the rotating wafer, which causes the wafer to be held unstable. In this embodiment, since the housings 52a, 52b are disposed away from the piston 51, no sliding resistance occurs between the piston 51 and the housings 52a, 52b. As a result, the substrate holding device 10 can hold the wafer W stably without applying an excessive load to the wafer W.

[0066] 5, the substrate holding device 10 includes a non-contact distance sensor 80 that measures the moving distance of the movable shaft 13b. The distance sensor 80 is disposed outside the actuator 18, and is disposed 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 moving distance of the magnet 81 relative to the distance sensor 80.

[0067] The position of the distance sensor 80 is fixed. Meanwhile, the movable base 21, the piston 51, and the movable shaft 13b can move together. Therefore, when the movable shaft 13b moves toward the reference shaft 13a and away from 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 moving distance of the magnet 81 corresponds to the moving distance of the movable shaft 13b. Therefore, the distance sensor 80 can measure the moving distance of the movable shaft 13b. The moving distance of 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 the predetermined reference position may be simply referred to as the position of the movable shaft 13b.

[0068] The distance sensor 80 is connected to the operation control unit 40, and the distance sensor 80 transmits a measured value of the moving distance of the movable shaft 13b (a measured value of the position of the movable shaft 13b) to the operation control unit 40. The operation control unit 40 can determine whether the substrate holding device 10 is holding the wafer W correctly (whether an abnormality occurs in the substrate holding device 10) by comparing the measured value of the moving distance of the movable shaft 13b (the position of the movable shaft 13b) with a preset threshold value. In one embodiment, the operation control unit 40 may issue an alarm signal when the measured value of the moving distance (the position of the movable shaft 13b) is greater than or smaller than the threshold value. In another embodiment, the operation control unit 40 may determine whether the substrate holding device 10 is holding the wafer W correctly (whether an abnormality occurs in the substrate holding device 10) by comparing an index value calculated from a plurality of measured values ​​of the moving distance (a plurality of measured values ​​of the position of the movable shaft 13b) with a preset threshold value. In another embodiment, the operation control unit 40 may issue an alarm signal when the index value is greater than or smaller than the threshold value. Examples of the index value include the average value of the position of the movable shaft 13b when the roller 11b rotates one or more revolutions, and the difference between the maximum and minimum values ​​of the position of the movable shaft 13b while the roller 11b rotates one or more revolutions (the amplitude of the position of the movable shaft 13b).

[0069] A possible reason why the measured value of the moving distance of the movable axis 13b when the movable axis 13b is moved in a direction approaching the reference axis 13a is smaller than the threshold value is that the wafer W is not properly held by the substrate holding device 10. A possible reason why the measured value of the moving distance is larger than the threshold value is that the wafer W is damaged or has become dislodged (the wafer W has fallen off or been lost from gripping).

[0070] Furthermore, in one embodiment, a first threshold value and a second threshold value smaller than the first threshold value may be set for the measured value of the moving distance of the movable shaft 13b. Specifically, the operation control unit 40 is configured to issue an alarm signal when the measured value of the moving distance is larger than the first threshold value, and to issue an alarm signal when the measured value of the moving distance is smaller than the second threshold value. The range from the second threshold value to the first threshold value is the range of the moving distance of the movable shaft 13b necessary for the rollers 11a and 11b to properly hold the wafer W.

[0071] When vibration occurs in the movable shaft 13b while the wafer W is rotating, the position of the movable shaft 13b (the measured value of the moving distance of the movable shaft 13b) changes according to the vibration. Therefore, the operation control unit 40 can detect the vibration of the movable shaft 13b based on the fluctuation of the position of the movable shaft 13b while the wafer W is rotating (the fluctuation of the measured value of the moving distance of the movable shaft 13b). Based on the vibration of the movable shaft 13b, the operation control unit 40 can detect the rotation abnormality of the wafer W when the substrate holding device 10 holds and rotates the wafer W. Possible causes of the rotation abnormality of the wafer W include wear, deformation, damage, or dimensional defects of the wafer holding surfaces 31a and 31b of the rollers 11a and 11b, or a rotation phase shift of the multiple rollers 11a and 11b.

[0072] In one embodiment, the operation control unit 40 may compare the amplitude of the measured value of the moving distance of the movable shaft 13b (the position of the movable shaft 13b) with a preset threshold value, and may determine that vibration has occurred in the movable shaft 13b when the amplitude is greater than the threshold value. The operation control unit 40 may issue an alarm signal when the amplitude is greater than the threshold value.

[0073] FIG. 8 is a diagram showing an example of the position of the movable axis 13b when an abnormality in the rotation of the wafer W occurs. The horizontal axis of the diagram indicates the rotation angle of the roller 11b, and the vertical axis of the diagram indicates the position of the movable axis 13b. In FIG. 8, the value indicating the position of the movable axis 13b becomes smaller as the movable axis 13b approaches the reference axis 13a, and becomes larger as the movable axis 13b moves away from the reference axis 13a. The position of the movable axis 13b being 0 is the position where the movable axis 13b is closest to the reference axis 13a within the movable range of the actuator 18. The rotation angle of the roller 11b being 0° is the predetermined reference angle of the roller 11b. In the example shown in FIG. 8, when an abnormality in the rotation 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 becomes greater than a predetermined amplitude threshold value. Possible causes of fluctuation in the position of movable shaft 13b shown in FIG. 8 include wear, deformation, damage, or dimensional defects of wafer holding surfaces 31a, 31b of rollers 11a, 11b, or deviation in the rotation phase of multiple rollers 11a, 11b.

[0074] The operation control unit 40 compares the amplitude of the position of the movable shaft 13b (the measured value of the moving distance of the movable shaft 13b) with a predetermined amplitude threshold value, and when the amplitude of the position of the movable shaft 13b is greater than the amplitude threshold value, it determines that an abnormality in the rotation of the wafer W has occurred. In this specification, the amplitude of the position of the movable shaft 13b is defined as the amplitude of the vibration of the movable shaft 13b. In the example shown in FIG. 8, the amplitude of the movable shaft 13b is the difference between the maximum value of the position of the movable shaft 13b and the minimum value of the position of the movable shaft 13b while the roller 11b rotates one or more times. In one embodiment, the operation control unit 40 may compare the amplitude of the position of the movable shaft 13b (the measured value of the moving distance of the movable shaft 13b) during the time from when the rotation time of the roller 11b has passed the first rotation time to when it reaches the second rotation time with a predetermined amplitude threshold value.

[0075] In addition, in one embodiment, the operation control unit 40 may issue an alarm signal when the amplitude of the position of the movable shaft 13b is greater than an amplitude threshold. In another embodiment, the operation control unit 40 may issue a command to the electric motors 29a, 29b to stop the operation of the electric motors 29a, 29b when the amplitude of the position of the movable shaft 13b is greater than an amplitude threshold.

[0076] FIG. 9 is a diagram showing another example of the position of the movable shaft 13b when an abnormality in the rotation of the wafer W occurs. Details of this embodiment that are not particularly described are the same as those of the embodiment described with reference to FIG. 8, so that the overlapping description will be omitted. In the example shown in FIG. 9, the average value of the position of the movable shaft 13b when the roller 11b rotates one or more times is smaller than the initial average value and the predetermined lower limit threshold value. In this embodiment, the initial average value is the average value of the movable shaft position (measurement value) when the rollers 11a, 11b are unused (not worn). The cause of the fluctuation in the position of the movable shaft 13b shown in FIG. 9 is considered to be wear, deformation, damage, or dimensional defects of the wafer holding surfaces 31a, 31b of the rollers 11a, 11b. The dotted line L1 in FIG. 9 indicates the average value of the position of the movable shaft 13b during the rotation of the wafer W when the wafer holding surfaces 31a, 31b are worn.

[0077] The operation control unit 40 compares the average value of the position of the movable shaft 13b when the roller 11b rotates one or more times (the average value of the measured values ​​of the moving distance of the movable shaft 13b) with a predetermined lower threshold value, and when the average value of the position of the movable shaft 13b is smaller than the lower threshold value, determines that a rotation abnormality of the wafer W has occurred. In one embodiment, the operation control unit 40 may compare the average value of the position of the movable shaft 13b when the roller 11b rotates one or more times (the average value of the measured values ​​of the moving distance of the movable shaft 13b) with a predetermined upper threshold value, and when the average value of the position of the movable shaft 13b is larger than the upper threshold value, determine that a rotation abnormality of the wafer W has occurred. As an example of a cause for the average value of the position of the movable shaft 13b to be larger than the upper threshold value, it is considered that the wafer W is not properly held by the substrate holding device 10. Depending on the setting of the reference position of the movable shaft 13b described above, the average position of the movable shaft 13b may become greater than the upper threshold value due to wear, deformation, damage, or dimensional defects of the wafer holding surfaces 31a, 31b of the rollers 11a, 11b.

[0078] In one embodiment, the operation control unit 40 may issue an alarm signal when the average value of the position of the movable shaft 13b when the roller 11b rotates one or more times is smaller than a lower threshold value (or the average value of the position of the movable shaft 13b when the roller 11b rotates one or more times is larger than an upper threshold value). Furthermore, in one embodiment, the operation control unit 40 may issue a command to the electric motors 29a, 29b to stop the operation of the electric motors 29a, 29b when the average value of the position of the movable shaft 13b when the roller 11b rotates one or more times is smaller than a lower threshold value (or the average value of the position of the movable shaft 13b when the roller 11b rotates one or more times is larger than an upper threshold value). An example of the alarm signal is a signal that prompts an operator to replace the rollers 11a, 11b.

[0079] According to the embodiment described with reference to Fig. 9, the operation control unit 40 can detect an abnormality in the rollers 11a, 11b regardless of whether the wafer holding surfaces 31a, 31b of the rollers 11a, 11b are worn evenly or unevenly. The embodiment described with reference to Fig. 8 and the embodiment described with reference to Fig. 9 may be combined. For example, the operation control unit 40 may determine that an abnormality has occurred and issue an alarm signal when the amplitude of the position of the movable shaft 13b is larger than an amplitude threshold value or when the average value of the position of the movable shaft 13b while the roller 11b has rotated one or more times is smaller than a lower limit threshold value.

[0080] The non-contact distance sensor 80 can accurately measure the moving distance of the movable shaft 13b without being affected by vibration even when the movable shaft 13b is vibrating. In this embodiment, a plurality of non-contact distance sensors 80 are provided to measure the moving distances of the plurality of movable shafts 13b, respectively. In one embodiment, a single non-contact distance sensor 80 may be provided to measure the moving distance of one of the plurality of movable shafts 13b.

[0081] In one embodiment, as shown in Fig. 10, the distance sensor 80 may be a non-contact optical sensor. Details of this embodiment that are not particularly described are the same as those of the embodiment described with reference to Figs. 5, 8, and 9, so that the overlapping description will be omitted. The distance sensor 80 of this embodiment includes a sensor head 84 having a light projecting section and a light receiving section (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 projecting 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.

[0082] The sensor head 84 is fixed to the outside of the actuator 18, and the tip of the sensor head 84 is disposed 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 disposed facing the sensor target 88. The sensor target 88 has a property of reflecting light. An example of the sensor target 88 is a member made of ceramic or metal. The amplifier 93 and the distance calculator 94 are located away from the actuator 18.

[0083] The amplifier 93 has a light source 93a that emits light and a light intensity meter 93b that measures the intensity of the reflected light. The light emitted from the light source 93a of the amplifier 93 is transmitted to the sensor head 84 through the light-projecting optical fiber cable 92A. The sensor head 84 guides 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. The light intensity meter 93b of the amplifier 93 measures the intensity of the reflected light. The amplifier 93 sends the measured value of the intensity of the reflected light to the distance calculator 94, which converts the measured value of the intensity of the reflected light into a distance. The distance obtained by the distance calculator 94 is the moving distance of the movable shaft 13b. With this configuration, the distance sensor 80 of this embodiment can measure the moving distance of the movable shaft 13b. The distance calculator 94 is connected to the motion control unit 40, and transmits a measurement value of the moving distance of the movable shaft 13b to the motion control unit 40. In one embodiment, the distance sensor 80 does not need to include the focusing lens 85. The sensor head 84 may direct light to the sensor target 88 without passing through the focusing lens 85, and may receive reflected light from the sensor target 88 without passing through the focusing lens 85.

[0084] As described above, among the elements constituting 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.

[0085] In one embodiment, the sensor head 84 and the focusing lens 85 may be disposed in the pressure chamber 57a (or in the pressure chamber 57b). In this case, the tip of the sensor head 84 is disposed facing the central portion 71a (or central portion 71b) of the partition film 55a (or partition film 55b), and the sensor head 84 guides light to the central portion 71a (or central portion 71b) and receives reflected light from the partition film 55a (or partition film 55b). A sensor target having a property of reflecting light may be fixed to the central portion 71a (or central portion 71b). Furthermore, in one embodiment, the distance sensor 80 may be a laser displacement meter.

[0086] In the embodiment described with reference to Fig. 1 to Fig. 10, the substrate holding device 10 includes two reference shafts 13a, two movable shafts 13b, two actuators 18, two movable bases 21, and two linear guides 26 arranged around the central axis line CP, but the number of these components and the intervals between their arrangements are not limited to this embodiment. In one embodiment, the substrate holding device 10 may include one movable shaft 13b and two or more reference shafts 13a arranged around the central axis line CP at appropriate intervals. In this case, the substrate holding device 10 includes one actuator 18, one movable base 21, and one linear guide 26.

[0087] Furthermore, in one embodiment, the substrate holding device 10 may include three or more movable shafts 13b and three or more reference shafts 13a arranged around the central axis line 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. Furthermore, in one embodiment, the motion control unit 40 may be composed of a plurality of motion control units each including a storage device and a calculation device. In one example, one of the plurality of motion control units may be connected to the electric motors 29a and 29b, and the other may be connected to the distance sensor 80.

[0088] Fig. 11 is a plan view showing a schematic diagram of an embodiment of a substrate processing apparatus including the substrate holding device 10 described with reference to Figs. 1 to 10, and Fig. 12 is a side view of the substrate holding device 10 shown in Fig. 11. In this embodiment, the substrate processing apparatus 100 includes the substrate holding device 10 and a processing head 200 that processes the first side 1 of the wafer W by bringing a processing tool 201 into contact with the first side 1 of the wafer W held by the substrate holding device 10. The processing head 200 is disposed below the wafer W held by the substrate holding device 10, and the position of the processing head 200 is fixed.

[0089] In this embodiment, the first surface 1 of the wafer W is the back surface of the wafer W on which no devices are formed or on which no devices are to be formed, i.e., the non-device surface. The second surface 2 of the wafer W opposite to the first surface 1 is the surface on which devices are formed or on which devices are to be formed, i.e., the device surface. In this embodiment, the wafer W is held horizontally by the substrate holding device 10 with the first surface 1 facing downward.

[0090] The specific operation of the substrate processing apparatus 100 of this embodiment is as follows: The substrate holding device 10 brings the rollers 11a, 11b into contact with the peripheral portion of the wafer W, rotates the rollers 11a, 11b about their respective axes, and causes the rollers 11a, 11b to make a circular motion, thereby rotating the wafer W about its axis and causing the wafer W to make a circular motion, while bringing the processing tool 201 into contact with the first surface 1 of the wafer W that is rotating and making a circular motion by the processing head 200, thereby processing the first surface 1 of the wafer W.

[0091] In this embodiment, the processing tool 201 is longer than the radius of the wafer W, one end of the processing tool 201 protrudes outward from the peripheral edge of the wafer W, and the other end extends 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 portion. The processing head 200 is disposed at a position where it does not come into contact with the rollers 11a, 11b and the eccentric shafts 13a, 13b when the wafer W is making a circular motion.

[0092] According to this embodiment, the substrate holding device 10 can rotate the wafer W around its axis while circularly moving the wafer W with a simple structure. The combination of such 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.

[0093] In one embodiment, the processing tool 201 may be a polishing tool for polishing the wafer W. Examples of the polishing tool include a polishing tape and a grindstone. Furthermore, in one embodiment, the processing tool 201 may be a cleaning tool for cleaning the wafer W. Examples of the cleaning tool include a cleaning tape. Examples of the cleaning tape include a tape made of nonwoven fabric.

[0094] The above-described embodiments have been described for the purpose of enabling a person having ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments are naturally possible for a person skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope according to the technical idea defined by the claims. [Explanation of symbols]

[0095] 1. First Side 2. The Second Side 10 Substrate holding device 11a, 11b Roller 13a,13b Eccentric shaft 14a, 14b First shaft portion 15a,15b 2nd shaft part 16a,16b Intermediate shaft part 17a,17b Counterweight 18 Actuator 19 Bearings 20 Base Plate 21 Movable platform 23 Connecting members 24 Bearings 26 Linear guide 27a,27b Motor support 28a, 28b Coupling 29a,29b Electric motor 31a, 31b Wafer holding surface (substrate holding surface) 40 Motion control section 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 part 74a,74b External wall part 75a,75b Thick part 80 Distance Sensor 81 Magnet 84 Sensor head 85 Focusing Lens 88 Sensor Target 92A Light emitting fiber optic cable 92B Receiver optical fiber cable 93 Amplifier 93a light source 93b Light intensity measuring device 94 Distance Calculator 100 Substrate processing apparatus 200 Polishing Head 201 Processing tools

Claims

1. A substrate holding device that rotates a substrate about its axis while causing the substrate to move in a circular motion, A plurality of rollers capable of contacting a peripheral portion of the substrate; A plurality of electric motors for rotating the plurality of rollers; A plurality of eccentric shafts arranged around a predetermined central axis; an actuator having a piston; a movable platform connected to the piston; The plurality of eccentric shafts include a plurality of first shaft portions and a plurality of second shaft portions each eccentric to the plurality of first shaft portions, The rollers are fixed to the second shaft portions, respectively, and the first shaft portions are connected to the electric motors, respectively; the plurality of eccentric shafts include one movable shaft and a plurality of reference shafts, the one movable table has a bearing that rotatably supports the one movable shaft and a connecting member fixed to the piston, The actuator is connected to the one movable shaft via the one movable base, the actuator is configured to move the one movable shaft and the one movable base together in a direction toward the plurality of reference axes and in a direction away from the plurality of reference axes, The actuator comprises: The piston and a housing disposed away from the piston; a partition membrane that forms a pressure chamber between the piston and the housing.

2. The plurality of eccentric shafts further include a plurality of intermediate shaft portions connecting the plurality of first shaft portions and the plurality of second shaft portions, The substrate holding device according to claim 1 , wherein the first shaft portions are fixed to the intermediate shaft portions, respectively, and the second shaft portions are fixed to the intermediate shaft portions, respectively.

3. 3. The substrate holding device according to claim 1, further comprising an operation control unit that rotates the plurality of electric motors at the same speed and in the same phase.

4. The substrate holding device according to claim 1 , wherein the directions toward and away from the plurality of reference axes are directions toward and away from the central axis.

5. A substrate holding device according to any one of claims 1 to 4, The substrate processing apparatus includes a processing head that brings a processing tool into contact with a first surface of a substrate to process the first surface.

Images