JP5563396B2 - Actuator and substrate transfer robot - Google Patents

Description

  The present invention relates to an actuator and a substrate transfer robot. In particular, the present invention relates to a substrate transfer robot for transferring a semiconductor wafer substrate, a liquid crystal display, a solar cell substrate, or a substrate for optical communication equipment, and an actuator used for the substrate transfer robot.

  A conventional actuator, substrate transfer robot, and process processing apparatus (for example, see Patent Document 1) will be described with reference to FIGS. A plurality of process processing apparatuses (hereinafter referred to as “processing chambers”) 1-6 shown in FIG. 7 are arranged radially about the substrate transfer robot 51. The substrate transfer robot 51 is arranged inside the transfer chamber 60 and transfers the substrate carried in from the load lock chamber (LL1) to each of the processing chambers 1-6. The substrate processed in each processing chamber is finally discharged from the load lock chamber (LL2). The substrate transfer robot 51 performs a rotation (+ α degree) operation of the first arm 52 and a rotation (−2α degree) operation of the second arm 53 at the same time, whereby the substrate configured at the tip of the second arm. The holding plate 54 can be operated so that the trajectory is linear. The processing chambers 1-6 are arranged radially around the substrate transfer robot 51. By moving the substrate holding plate 54 linearly based on the rotation of the first arm 52 and the second arm 53, the substrate transfer robot 51 can transfer the substrate to each processing chamber. After the processing of the substrate is completed in the processing chamber, the substrate transfer robot 51 ejects the substrate from the processing chamber and transfers the substrate to another processing chamber that performs the next processing.

  An outline of the substrate transfer robot 51 will be described. When the outer shaft 490 is rotated while the inner shaft 480 connected to the belt 55 is fixed (not rotated), the first arm 52 rotates (+ α angle) about the central axis. Due to the action of the belt 55 connected to the pulley 58 having a predetermined number of teeth inside the first arm 52, the second arm 53 has a predetermined angle (for example, double) in the direction opposite to the rotation of the first arm 52. -2α angle). Since the substrate holding plate 54 is configured to be able to rotate at the same angle in the same direction as the first arm 52, as a result, the substrate holding plate 54 is linearly moved only by rotating the outer shaft 490. Can be moved directly. By this linear motion, the substrate placed on the substrate holding plate 54 can be transported into the processing chamber. After the substrate processing is completed in the processing chamber, the substrate transfer robot 51 discharges the substrate from the processing chamber by a linear motion operation. Then, by rotating the outer shaft 490 and the inner shaft 480 of the substrate transfer robot 51 in the same direction in synchronization, the direction of the substrate transfer robot 51 is changed, and the substrate is transferred to another processing chamber (hereinafter referred to as arm revolution). ) Is possible.

  Patent Document 2 proposes an arm configured without a belt. In the case of the arm of Patent Document 2, when the arm revolves, the direction of the substrate transport robot can be changed by rotating the outer shaft and the inner shaft in the same direction in synchronization with each other as in FIG. Further, by synchronizing the driving of the first arm and the driving of the second arm and rotating them by a predetermined angle in the same manner as in Patent Document 1, a linear motion operation is realized. Further, there is a substrate transport robot equipped with a vertical mechanism for moving the substrate holding plate of the substrate transport robot up and down in order to change the substrate. Since the substrate processing in each processing chamber is performed in a vacuum environment, the substrate transfer robot 51 is configured to be operable without deteriorating the vacuum environment of the transfer chamber 60 functioning as a vacuum chamber.

  The substrate transfer robot of FIG. 6 has a rotation drive mechanism that operates the first arm and a rotation drive mechanism that operates the second arm (upper motor 400, lower motor 410). The substrate transfer robot has two sets of a rotor and a stator that directly drive a drive shaft connected to an arm connected to a substrate holding plate that holds the substrate. In the case of vacuum compatibility, a housing 430 having a vacuum partition function is provided between the rotor and the stator. Between the housing 430 and the vacuum chamber, the periphery of the outer shaft 490 is covered with a bellows 495 and the airtight state inside the housing is maintained. The rotors (inner shaft rotor 440 and outer shaft rotor 450) having permanent magnets are arranged in alignment with the stators (inner shaft stator 445 and outer shaft stator 455) fixed to the housing 430. The inner shaft 480 driven by the lower motor 410 and the outer shaft 490 driven by the upper motor 400 are arranged so as to be coaxial, and the upper motor 400 and the lower motor 410 are provided in series in the vertical direction. It has become. Also, sensors for detecting the rotational position (inner shaft encoder 460, outer shaft encoder 465) are provided, and the rotational position and rotational angle of the drive shaft can be detected.

  The substrate transfer robot rotates the rotor (inner shaft rotor 440, outer shaft rotor 450) by a predetermined angle based on the electric power supplied to the stators (inner shaft stator 445, outer shaft stator 455), and the substrate holding plate 54. The substrate placed on is transported as described in FIG.

Japanese Patent Registration No. 02761438 Japanese Patent Laid-Open No. 10-128692

  However, in the configuration shown in FIG. 6, the set of the rotor and the stator is arranged in series, so that it becomes longer in the direction of the rotation axis of the rotation drive mechanism. For this reason, it is necessary to increase the substrate transfer line (pass line) for transferring the substrate. That is, it is necessary to increase the substrate transfer line (pass line) of each processing chamber apparatus as a whole, and the entire apparatus must be enlarged.

  Further, magnets used for the inner shaft rotor 440 and the outer shaft rotor 450, for example, neodymium magnets, are expensive materials. When separate magnets are used for the inner shaft and the outer shaft, the cost of the actuator is increased. There is also a problem.

  It is an object of the present invention to provide an actuator in which the length of the drive mechanism in the direction of the rotation axis is made compact. Alternatively, an object is to provide a low-cost actuator by integrating an inner shaft magnet and an outer shaft magnet.

An actuator according to one aspect of the present invention that achieves at least one of the above objects has a hollow structure, and is configured to be able to evacuate the inside of the hollow structure. A housing for holding the first coil portion;
An inner shaft that is rotatably supported inside the housing, has a second coil portion on the outer periphery, and has a hollow structure at least partially ;
A cylindrical outer shaft that is rotatably supported inside the housing coaxially with the rotation shaft of the inner shaft, and is disposed so as to surround the outer peripheral side of the inner shaft;
A magnet facing the first coil portion on the outer peripheral side of the outer shaft and facing the second coil portion on the inner peripheral side of the outer shaft;
Provided in said shaft, and arranged commutator on the inner peripheral surface of the hollow structure of the inner shaft,
Provided in said shaft, and a brush in sliding contact with the commutator when said shaft is at least rotated,
The second coil part is fed through the commutator and the brush ,
The brush is inside the hollow structure of the inner shaft, sliding and placed the commutator in the inner peripheral surface Sessu characterized Rukoto.

  According to the present invention, it is possible to provide an actuator in which the length of the drive mechanism in the rotation axis direction is made compact.

  Alternatively, according to the present invention, it is possible to provide a low-cost actuator by integrating the magnet for the inner shaft and the magnet for the outer shaft.

The figure explaining the structure of the actuator which concerns on embodiment of this invention. The figure which shows the AA sectional drawing of FIG. The figure which shows the example which applied the actuator concerning embodiment of this invention to the drive motor of the board | substrate conveyance robot. The figure which shows the modification 1 of embodiment of this invention. The figure which shows the modification 2 of embodiment of this invention. The figure explaining the conventional board | substrate conveyance robot. The figure explaining the conventional board | substrate conveyance robot.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the constituent elements described in this embodiment are merely examples, and the technical scope of the present invention is determined by the scope of claims, and is limited by the following individual embodiments. is not.

(Configuration of actuator)
The configuration of the actuator according to the embodiment of the present invention will be described with reference to FIG. In the following description, the configuration in which the actuator is driven in the chamber in a vacuum environment is described as an example. However, the gist of the present invention is not limited to this example, and the actuator is driven in an atmospheric pressure environment. It can also be applied to actuators.

  FIG. 1 is a longitudinal sectional view of an actuator 1000 according to an embodiment of the present invention. The actuator 1000 can independently rotate and drive two shafts (inner shaft and outer shaft) arranged concentrically. Of the two shafts, a relatively inner shaft is referred to as an inner shaft 110, and a relatively outer shaft is referred to as an outer shaft 120. A motor that drives the inner shaft 110 is referred to as an inner shaft motor 113, and a motor that drives the outer shaft 120 is referred to as an outer shaft motor 123. An outer shaft motor 123 is disposed on the outer peripheral side of the inner shaft motor 113 coaxially with the rotation axis of the inner shaft motor 113 as a reference. By arranging the inner shaft motor 113 and the outer shaft motor 123 coaxially, the length in the rotation axis direction can be shortened. Moreover, the control responsiveness at the time of synchronous rotation can be made uniform by changing the generated torque in order to make the operation speed uniform.

  The outer shaft stator 122 includes a housing 129 that functions as a vacuum partition, and the housing 129 is provided with a predetermined number of teeth 128. A conductive wire is wound around each tooth 128 to form an outer shaft coil 124 (first coil portion). Predetermined electric power can be supplied from the outside to the outer shaft coil 124 (first coil portion). The outer shaft stator 122 of the present embodiment is configured by assembling the teeth 128 and the vacuum partition formed separately, but it is also possible to form the teeth 128 and the housing 129 integrally to form a vacuum partition. It is. The outer shaft stator 122 or the teeth 128 is made of a material having a small iron loss such as a silicon steel plate or permalloy. Further, it is more preferable that a large number of plate materials made of these materials are laminated in the axial direction (vertical direction).

  The vacuum partition is a thin tubular member that hermetically separates the space between the tooth 128 and the outer shaft 120, and the inside of the vacuum partition is configured to be evacuated. Further, a part of the teeth 128 may be protruded to the vacuum side of the vacuum partition. In this case, the number of holes 128 through which one end portion of the teeth 128 is inserted into the vacuum partition may be formed so that no gap is formed between the teeth 128 and the holes of the vacuum partition. Moreover, you may provide the yoke protruded inside the vacuum partition. In this case, the yoke may be attached to a portion corresponding to the end portion of the tooth 128 inside the vacuum partition wall. Of course, you may form as a vacuum partition which has an unevenness | corrugation in an inner surface.

  The housing 129 has a hollow structure in which an O-ring 500 is sandwiched between the joining portions of the constituent members, and the inside thereof communicates with the vacuum chamber 101 and can be evacuated. The periphery of the outer shaft 120 extending from the housing 129 to the vacuum chamber 101 is covered with an airtight holding member (bellows 190), and the airtight state inside the housing 129 is maintained. Inside the housing 129 having a hollow structure, the inner shaft 110 is supported by a bearing 600 and the outer shaft 120 is rotatably supported by a bearing 700. The inner shaft 110 and the outer shaft 120 can rotate independently.

  The inside of the housing 129 is a region where the inner shaft 110 and the outer shaft 120 are disposed and can be evacuated. The outside of the housing 129 is exposed to the atmosphere side, and the outer yoke 127, the teeth 128, and the outer shaft coil 124 are disposed on the atmosphere side. In the housing 100 constituted by the bottom member 180 and the cylindrical member 181, a brush 132, an outer shaft read head 134 a, and an inner shaft read head 136 a are disposed on the vacuum side. An airtight state is maintained by sandwiching an O-ring 501 between the bottom surface member 180 and the cylindrical member 181 constituting the housing 100.

  The outer shaft 120 is disposed inside the outer shaft stator 122 via a bearing 700, and a tubular magnet member 117 is connected to a tubular (cylindrical) outer shaft shaft 115 as an output shaft. The magnet member 117 is opposed to the inner side (inner peripheral side) of the housing 129 in which the outer shaft coil 124 (first coil portion) is held. A disk 134b that is paired with the outer shaft read head 134a is attached to the lower end of the outer shaft 115. The outer shaft read head 134a and the disk 134b constitute main components of the encoder 134 that measures the rotation angle of the outer shaft 120.

  The magnet member 117 is fixed to the outer shaft shaft 115 in a state where the axes of the outer shaft stator 122 and the outer shaft shaft 115 are aligned. The magnet member 117 in the present embodiment is composed of a predetermined number of permanent magnets 227 attached so as to penetrate the tubular outer shaft shaft 115 in the radial direction. The magnet member 117 may be configured by arranging a predetermined number of permanent magnets side by side on the inner peripheral surface and the outer peripheral surface of the tubular outer shaft shaft 115. The permanent magnet 227 is composed of a plurality of segment-type permanent magnets magnetized so that the magnetic flux is directed in the radial direction of the outer shaft 115. In the present embodiment, 16 rectangular segment magnets that are elongated in the vertical direction are arranged around the outer shaft 115 so that the polarities are staggered. As the magnet material, for example, any permanent magnet such as samarium (Sm), neodymium (Nd), or ferrite can be applied. The permanent magnet 227 is preferably attached to the outer shaft 115 with a skew angle in order to suppress cogging.

  The inner shaft 110 is disposed inside the outer shaft 120 via a bearing 600, and is configured by connecting an inner shaft coil 112 (second coil portion) to an inner shaft shaft 116 serving as an output shaft. . The inner shaft coil 112 (second coil portion) is disposed so as to face the magnet member 117, and is configured to function as a motor with the magnet member 117. One set of magnet members 117, one set of outer shaft coil 124 (first coil portion), one set of inner shaft coil 112 (second coil portion), and two more shafts (inner shaft 110, outer The shaft 120) can be driven. In addition, a commutator 131 is disposed on the lower side of the inner shaft 110 at a position in sliding contact with the brush 132, and power is supplied to the inner shaft coil 112 (second coil portion) by the brush 132. A disk 136b that is paired with the read head 136a is attached below the inner shaft 116 of the inner shaft 110. The read head 136a and the disk 136b constitute main components of the encoder 136 that measures the rotation angle. The commutator 131 is provided on one of the inner shaft 110 and the housing, and is electrically connected to the inner shaft coil 112 (second coil portion). The brush 132 is provided on the other of the inner shaft 110 and the housing, and is in sliding contact with the commutator 131 when the inner shaft 110 rotates at least.

  The characteristic configuration of the present invention will be described below with reference to FIG. A predetermined number of teeth 128 are provided inside the housing 129. A conductive wire is wound around each tooth 128 to form an outer shaft coil 124 (first coil portion). The inner shaft coil 112 (second coil portion) is a member formed by winding a conductive wire around each of the six teeth 201 radially attached to the outer peripheral side of the inner shaft shaft 116. Are connected with the center axis aligned. Since each tooth 201 is a substantially plate-like member arranged in the vertical direction, the conductive wire wound around each tooth forms a long and narrow coil in the vertical direction. Each tooth 201 includes a core holder portion 202 on the side facing the magnet member 117.

  The commutator 131 is a conductive member that can be attached to the outer periphery of the inner shaft 116 so as to be in sliding contact with the brush 132 when the inner shaft 110 rotates. The commutator 131 receives electric power supplied from the brush 132 through the power supply wiring. , Converted into electric power for driving the inner shaft and supplied to each of the inner shaft coils 112. The brush 132 is a member attached to the inside of the housing 100 so as to be in sliding contact with the commutator 131, and is constantly pressed against the commutator 131 by a biasing member such as a spring. The brush 132 is connected to an external power source (not shown).

  In this embodiment, the commutator 131 is attached to the inner shaft 110 and the brush 132 is attached to the housing 100. However, it is needless to say that the commutator 131 may be attached to the housing 100. Further, if the member located inside the centrifugal direction in the brush 132 or the commutator 131 is configured to be deformed outward by the rotation of the inner shaft 110, the brush 132 and the commutator 131 are in sliding contact only when the inner shaft 110 rotates. Can be.

  In the example shown in FIG. 2, for example, a three-phase 8-pole 24-coil is used as the configuration of the outer shaft coil 124 (first coil portion). In addition, a configuration example in which 16 poles are used as the configuration of the magnet member 117 and 6 coils are used as the inner shaft coil 112 (second coil portion) is shown. It is not limited and other combinations can be adopted as appropriate. Moreover, in this embodiment, as a conducting wire wound around the outer shaft coil 124 (first coil portion) and the inner shaft coil 112, for example, a 1.0 mm diameter coated with polytetrafluoroethylene (PTFE) insulating film. Wires are used, but conductive wires such as polyester enamel wires can be used as appropriate. However, a PTFE insulating film wire that emits less gas is more suitable.

(Actuator operation)
Next, operations of the inner shaft 110 and the outer shaft 120 of the actuator 1000 will be described. First, when only the inner shaft 110 is rotated, electric power is supplied to the outer shaft coil 124 and the magnet member 117 of the outer shaft 120 is fixed by the generated magnetic field. In this state, the inner shaft coil 112 is excited from the brush 132 to rotate the inner shaft 110. At this time, the outer shaft coil 124 does not change the coil to be excited, so that the magnet member 117 does not rotate and the magnet member 117 is magnetically coupled to the inner shaft coil 112 more strongly. Therefore, the servo lock state in which the position of the outer shaft 120 is maintained between the outer shaft coil 124 and the magnet member 117, that is, the outer shaft coil 124 and the magnet member 117 are substantially DC motors (servo motors). ) Is configured. The inner shaft 110 can be rotated in reverse by changing the direction of the electric power supplied to the inner shaft coil 112.

  When only the outer shaft 120 is rotated, the outer shaft coil 124 sequentially changes the exciting coil to rotate the magnet member 117. At this time, electric power is supplied from the brush 132 to the inner shaft coil 112 according to the detection value from the encoder 136 of the inner shaft 110 so that the inner shaft 110 does not rotate due to the magnetic field of the magnet member 117. A DC motor (servo motor) is substantially constituted between the inner shaft coil 112 and the magnet member 117. Note that a configuration may be adopted in which preset power is supplied from the brush 132 without using the detection value of the encoder 136. The outer shaft 120 can be reversely rotated by changing the direction of the electric power supplied to the outer shaft coil 124. When the inner shaft 110 and the outer shaft 120 are simultaneously rotated in the same direction (revolution operation), the detected value from the encoder 136 of the inner shaft 110 and the detected value from the encoder 134 of the outer shaft 120 are synchronized with the inner shaft 110. The outer shaft 120 is rotated.

  In order to change the rotational speed of the inner shaft 110, power is supplied from the brush 132 to the inner shaft coil 112. At this time, since the inner shaft 110 is displaced relative to the magnet member 117, the rotation angle and the rotation speed are controlled based on the detection value of the encoder 136. When the inner shaft 110 is rotated in the reverse direction, the outer shaft coil 124 sequentially changes the coil to be excited to rotate the magnet member 117 in the reverse direction and supplies power from the brush 132 to the inner shaft coil 112. At this time, since the inner shaft 110 is displaced relative to the magnet member 117, the rotation angle and the rotation speed are controlled based on the detection value of the encoder 136.

(Application to substrate transfer robot)
The actuator 1000 according to the embodiment of the present invention can be applied to a drive motor (drive source) of a substrate transfer robot. FIG. 3A shows a configuration example in which a substrate transfer robot 351 is attached via a bellows 190 to a transfer chamber 301 whose inside can be evacuated. By attaching the vertical movement mechanism 337 to the motor casing 350, the vertical position of the motor casing 350 (actuator 1000) can be operated with respect to the transfer chamber 301. As shown in FIG. 3B, the substrate transfer robot 351 is an articulated robot and includes an arm mechanism 336 that holds and transfers the substrate 341. The arm mechanism 336 includes a substrate holder 336a on which a substrate can be placed and two arms 336b and 336c. The arm 336c can be driven by the rotation of the outer shaft 120 of the actuator 1000, and the arm 336b can be driven by the rotation of the inner shaft 110. The substrate holder 336a can place the substrate 341 and is rotatably supported at one end of the arm 336b. The other end of the arm 336b is rotatably supported on the arm 336c.

  It is also possible to configure an electronic device manufacturing system for manufacturing an electronic device by applying the actuator 1000 according to the embodiment of the present invention to a substrate transfer robot. Examples of the electronic device include a semiconductor, a liquid crystal display, a solar cell, or a device for optical communication equipment. An electronic device manufacturing method executed in the electronic device manufacturing system includes a transport process for transporting a substrate using a substrate transport robot using an actuator 1000, and a substrate transported in the transport process in at least one process processing apparatus. On the other hand, it has a process execution step of executing a device manufacturing process.

  According to the present embodiment, it is possible to provide an actuator in which the length of the drive mechanism in the direction of the rotation axis is made compact. Alternatively, according to the present embodiment, it is possible to provide a low-cost actuator by integrating the magnet for the inner shaft and the magnet for the outer shaft.

(Modification 1)
A first modification of the configuration of the actuator 1000 described in FIG. 1 will be described with reference to FIG. For example, as shown in FIG. 4, at least a part of the inner shaft 110 has a cylindrical portion (hollow structure). The inner shaft 110 is provided with a wiring hole 477 for passing a power supply wiring for supplying power to the inner shaft coil 112 (second coil portion). The power supply wiring that electrically connects the inner shaft coil 112 (second coil portion) and the commutator 131 is a wiring hole 477 that communicates from the outer peripheral surface of the inner shaft 110 to the inside of the cylindrical portion (inside the hollow structure). As described above, wiring is performed inside the cylindrical portion of the inner shaft 110 (inside the hollow structure). In the case where the bearing 600 that rotatably supports the inner shaft 110 is disposed below the inner shaft 110, the power supply wiring is wired inside the inner shaft 110 through the wiring hole 477, and the bearing 600 and the power supply wiring are arranged. Avoid interference. It is possible to configure such that the power supply wiring is led out from the opening at the lower end of the inner shaft 110 to the outside of the inner shaft 110 and connected to the commutator 131. According to the first modification, interference between the bearing 600 and the power supply wiring can be effectively avoided without adding a mechanical component.

(Modification 2)
A modification 2 of the configuration of the actuator 1000 described in FIG. 1 will be described with reference to FIG. In the structure shown in FIG. 5, the commutator 131 is disposed on the inner peripheral surface of the hollow structure of the inner shaft 110. The brush 132 is disposed inside the inner shaft 110 so as to be in sliding contact with the commutator 131 when the inner shaft 110 rotates. The power supply wiring is wired inside the inner shaft 110 through the wiring hole 477, and the power supply wiring and the commutator 131 are connected inside the inner shaft 110. A particle cover 555 is provided at the lower end of the inner shaft 110. The particle cover 555 is provided with an opening 556 for passing a power supply wiring that connects the brush 132 and an external power supply (not shown). The power supply wiring is connected to an external power supply through the opening 556. According to the second modification, by arranging the brush 132 and the commutator 131 inside the inner shaft 110, particles (particles) generated by the sliding contact between the brush 132 and the commutator 131 enter the vacuum chamber 101. This can be prevented.

101 Vacuum chamber 112 Inner shaft coil 117 Magnet member 124 Outer shaft coil 131 Commutator 132 Brush 227 Permanent magnet

Claims (4)

A housing having a hollow structure, configured to be able to evacuate the inside of the hollow structure, and holding the first coil portion on the outer peripheral side of the hollow structure;
An inner shaft that is rotatably supported inside the housing, has a second coil portion on the outer periphery, and has a hollow structure at least partially ;
A cylindrical outer shaft that is rotatably supported inside the housing coaxially with the rotation shaft of the inner shaft, and is disposed so as to surround the outer peripheral side of the inner shaft;
A magnet facing the first coil portion on the outer peripheral side of the outer shaft and facing the second coil portion on the inner peripheral side of the outer shaft;
Provided in said shaft, and arranged commutator on the inner peripheral surface of the hollow structure of the inner shaft,
Provided in said shaft, and a brush in sliding contact with the commutator when said shaft is at least rotated,
The second coil part is fed through the commutator and the brush ,
Said actuator brush, to the inside of the hollow structure, wherein sliding Sessu Rukoto said commutator disposed in the inner peripheral surface of the inner shaft. 2. The actuator according to claim 1, wherein a particle cover for reducing an inner diameter of the inner shaft is provided at a portion where the hollow structure of the inner shaft is in contact with the inner space of the housing. Electrically connected feed line in front Symbol second coil portion, as the opening of the particles cover communicating from the outer peripheral surface of the inner shaft into the interior of the hollow structure, the inside of the hollow structure of the inner shaft The actuator according to claim 2 , wherein the actuator is wired through.   A substrate transfer robot comprising the actuator according to any one of claims 1 to 3.

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