WO2004079884A1

WO2004079884A1 - In-vacuum drive device and substrate transportation system using the same

Info

Publication number: WO2004079884A1
Application number: PCT/JP2004/002773
Authority: WO
Inventors: Ryuichiro Tominaga; Takao Fujii
Original assignee: Kabushiki Kaisha Yaskawa Denki
Priority date: 2003-03-07
Filing date: 2004-03-04
Publication date: 2004-09-16
Also published as: JP2004274889A; TW200509504A; JP4363064B2

Abstract

An in-vacuum drive device has a first movable element (8) provided on the atmosphere side opposite a vacuum-chamber wall (5) and having a magnetic field system movably provided through a sliding portion, a second movable element (11) provided on the vacuum side opposite the vacuum-chamber wall (5) and having a magnetic field system movably provided on the vacuum side through a sliding portion, a drive portion fixed on the atmosphere side of the vacuum chamber wall (5) and having a stator with an armature (3) provided opposite the first movable element (8) with a magnetic gap in between, an encoder provided on the first movable element (8) and constituted of a sensor head (12) and a linear scale (13) that are used for detecting the position of the first movable element (8) in the movement direction with respect to the vacuum chamber, and phase difference-detecting means (magnetic sensor (4)) provided on the first movable element (8) and detecting a phase displacement between the first movable element (8) and the second movable element (11). Electric power is supplied to the armature (3) so that a position command signal is in accordance with a position command of the first movable element (8) detected by the encoder. Control means (not shown) is provided, and the means corrects a position command signal so as to reduce a phase difference detected by the phase difference-detecting means.

Description

Specification

In-vacuum driving device and substrate transfer device using the same

The present invention relates to a robot, a wafer stage, and a robot that transports a wafer substrate using a second movable element disposed in a vacuum by combining one or a plurality of in-vacuum driving devices realized as a linear motor or a rotary motor. In addition to this, it is possible to realize a substrate transfer device including a transfer means such as the above, and also in this substrate transfer device, eliminate any wiring in the vacuum chamber and significantly reduce generation of gas and particles in the vacuum chamber. The present invention relates to an in-vacuum drive device having a simple configuration and a substrate transfer device using the same.

[Background]

Conventionally, devices that transport semiconductor wafers in semiconductor manufacturing equipment used in processes such as chemical vapor deposition (CVD) for manufacturing semiconductor devices, for example, motors that drive these devices are in a vacuum environment. Driven below. Equipment used in this clean vacuum environment is required to generate gas particles and have a small rise in temperature. The generation of gas and particles lowers the required cleanliness, and the rise in temperature has an adverse effect on temperature-manufacturing processes for semiconductors and the like.

Conventionally, as an example of driving a linear motor in a vacuum, for example, as disclosed in Japanese Patent Application Laid-Open No. 2001-238428 and Japanese Patent Application No. 2001-367067, an armature A can-liner motor has been proposed in which the winding is directly cooled by a refrigerant. The canned linear motor has a moving coil type in which an armature is used as a movable element and a field is used as a stator (Japanese Patent Laid-Open No. 2001-238428), and a field is used as a movable element and the armature is used as a stator. Movable magnet type (Japanese Patent Application No. 2001-367067). Fig. 7 shows a movable coil type. FIG. 7 is a perspective view showing the whole of a conventional movable coil type linear motor. '' In Fig. 7, 51 is a mover, 52 is a mover base, 53 is a can, 54 is a refrigerant supply port, 55 is a refrigerant outlet, 56 is a cable for power supply and signal, 57 Is a stator, 58 is a stator base, 59 is a field yoke, and 60 is a field magnet.

The mover 51 has a T-shape. The mover base 52, the can 53 supported downward by the mover base 52, and the can 53 are sealed. A header (not shown), a winding fixed frame (not shown) provided in a space formed by the can 53 and the header, and a coreless three-phase armature winding fixed to the winding fixed frame. (Not shown) and a refrigerant passage (not shown) passing through the can.

The mover 51 is supported by a linear guide (not shown) or the like. The mover 51 also has a refrigerant supply port 54 and a refrigerant discharge port 55 for passing the refrigerant, and supplies the refrigerant from the refrigerant supply port 54 and discharges it from the refrigerant discharge port 55. This allows the refrigerant to flow through the cold passage between the armature winding and the can 53.

Further, the stator 57 includes a field magnet 60 arranged so as to face the armature portion via a magnetic gap, a plate-shaped field yoke 59 holding the field magnet 60, and , Is composed of

As shown in FIG. 7, the canned linear motor has a power line for supplying electric power to the armature coil, a cable 56 such as a signal line for a position sensor, or a cooling pipe (not shown) provided in a vacuum chamber. It is drawn out of the vacuum chamber via the introduction port.

By passing a predetermined current through the armature winding of the armature in such a configuration, it acts on the magnetic field generated by the field magnet 60 to generate thrust on the mover 51 and travel in the direction indicated by the arrow. It is possible to move to. Then, the armature winding generated by the copper loss is cooled by the refrigerant to suppress the temperature rise on the mover surface.

As a countermeasure against gas generation, a linear motor has a magnetic field provided with a Ni plating or a Cu plating (Japanese Patent Application Laid-Open No. 8-167665).

However, in such a conventional structure, since cables such as power lines and signal lines are coated with synthetic resin, measures for generating gas are required, and measures for cooling the heat-generating portion are required. If the reversing motor is a movable coil type, the movable coil is placed in the vacuum chamber, so that the motor leads, signal lines, and cooling pipes are routed in the vacuum chamber, and as a result, particles are generated. Inevitable. In addition, even when the linear motor is a movable magnet type, it is necessary to provide a sensor head on the mover side and to route the signal line on the mover side. Particles are generated from the signal line. In addition, since the linear motor requires a cooling device, the configuration is complicated. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has a simple configuration of a vacuum having no partakes without laying a motor lead wire, a signal wire, a cooling pipe, etc. in a vacuum chamber. It is an object to provide an internal drive device and a substrate transfer device using the same.

[Disclosure of the Invention]

In order to solve the above problem, a vacuum drive device according to the invention of claim 1 is provided on the atmosphere side facing the wall surface of the vacuum chamber, and is arranged to move independently via a sliding portion. A first movable element having a magnetic field, a second movable element having a magnetic field movably disposed on the vacuum side via a sliding portion via the wall surface of the vacuum chamber, and A drive unit fixed to the atmosphere and comprising a stator comprising an armature opposed to the first mover via a magnetic gap; and a drive unit provided on the first mover and provided to the vacuum chamber. (1) an encoder that detects a position of the mover in the moving direction; and a phase difference detection unit that is provided on the first mover and detects a phase shift between the first mover and the second mover. And the position command signal is detected by the encoder. Control means for supplying power to the armature so as to match the position command of the first mover and correcting the position command signal so as to suppress the phase difference detected by the phase difference detection means. It is characterized by having provided.

In the vacuum drive device according to the first aspect, when a position command is input from a host controller or the like, power is supplied to the armature by the control means, and a moving magnetic field is generated. Due to the magnetic action between the moving magnetic field and the respective fields of the first mover and the second mover, the first mover and the second mover move in a predetermined direction. System The control means controls the power supplied to the armature so that the position of the first mover detected by the encoder matches the position command. If a phase shift in the thrust direction occurs between the first mover and the second mover, an output corresponding to the phase shift is output to the phase difference detection means, so that the position command signal is controlled so as to suppress the phase shift. By performing the correction, the second mover is controlled so as to match the position command.

Only the second armature and the sliding part are arranged inside the vacuum chamber, and the armature having lead wires, the phase difference detecting means and the encoder with wiring are arranged outside the vacuum chamber, so the vacuum chamber Particle generation in the interior is significantly reduced.

The invention according to claim 2 is characterized in that the drive unit is constituted by a linear motor, and the field of the first mover has a plate-shaped first field yoke and polarities alternate in the longitudinal direction of the first field yoke. A first field magnet in which a plurality of magnetic poles are arranged so as to be different from each other, and the field of the second mover is a plate-shaped second field yoke and a longitudinal axis of the second field yoke. And a second field magnet in which a plurality of magnetic poles are arranged so that the polarities are alternately different in the direction.The armature is configured by an armature coil including a plurality of smooth coil groups. Characterize.

According to the second aspect, the in-vacuum driving device according to the first aspect is constituted by a linear motor.

The invention according to claim 3 is characterized in that the drive unit is constituted by a rotary motor, and the field of the first movable element is formed by forming a plurality of magnetic poles such that polarities are alternately different in a circumferential direction. The field of the second mover is formed of a plate-shaped first field magnet, and the field of the second mover is a disk-shaped second field magnet having a plurality of magnetic poles formed so that the polarities are alternately different in the circumferential direction. Wherein the armature comprises an armature coil comprising a plurality of ring-shaped coil groups.

According to the third aspect, the in-vacuum driving device according to the first aspect is constituted by a rotary motor.

The invention according to claim 4 is characterized in that a magnetic sensor that detects a magnetic flux in a thrust direction and a magnetic flux in an I gap direction is used as the phase difference detecting means.

In this claim 4, the phase shift between the first mover and the second mover is caused by the thrust It is detected as a change in directional magnetic flux. 'The invention according to claim 5 is characterized in that a transmission type optical sensor is used as the phase difference detecting means. ,

According to the fifth aspect, the phase shift between the first mover and the second mover is output as a change in the duty ratio of the output of the optical sensor.

The invention according to claim 6 is characterized in that the encoder is provided on the first movable element in opposition to the optical linear scale, the optical linear scale being disposed on the atmosphere side of the wall surface of the vacuum chamber. An optical encoder comprising the sensor head for detecting the linear scale.

In the present invention, the relative position change between the wall surface of the vacuum chamber and the first mover is detected by the sensor head, and is fed back to the control means as a position signal.

The invention according to claim 7 is characterized in that a rolling bearing is provided on the sliding portion, and molybdenum disulfide and / or molybdenum disulfide are provided on all or a part of the sliding surface of the inner ring and the outer ring of the rolling bearing arranged on the vacuum side. It is characterized in that a thin film of a solid lubricant composed of any one of tundastene sulfide and silver is formed.

In this aspect, by forming a thin film of the solid lubricant of the above-mentioned material on the sliding surface arranged on the vacuum side, the sliding surface is peeled off due to sliding and particles are generated due to scattering of particles. Can be suppressed.

A substrate transfer device according to claim 8 is a transfer device for transferring a wafer substrate by the second movable element using the in-vacuum drive device including the drive unit according to any one of claims 1 to 7. 'Is provided.

In this claim 8, by combining one or more of the in-vacuum driving devices, a robot, a wafer stage, etc., for transporting the wafer substrate using the second movable element arranged in the vacuum. Thus, a substrate transfer device including the transfer means can be realized.

[Brief description of drawings]

FIG. 1 is a side sectional view of a linear motor according to a first embodiment of the present invention, FIG. 2 is a front sectional view of a linear motor according to the first embodiment, and FIG. 3 is a sectional view according to the first embodiment. FIG. 4 is a cross-sectional view of a rotary motor according to a second embodiment of the present invention, and FIG. 5 is a plan view of a substrate transfer device according to a third embodiment of the present invention. FIG. 6 is a front view of a substrate transfer device according to a third embodiment, and FIG. 7 is a perspective view showing a configuration of a conventional canned linear motor. In addition, 1 in the figure is the first field yoke, 2 is the second field yoke, 3 is the armature, 4 is the magnetic sensor, 5, 5, and 5 are the chamber walls, 6 is the linear guide, and 7 is the symbol. 1st field magnet, 8 is the 1st mover, 9 is the linear guide, 10 is the 2nd field magnet, 1 is the 2nd mover, 1 is the sensor head, 13 is the linear scale, 2 1 Is the first housing, 22 is the bearing, 23 is the shaft, 24 is the first rotor, 25 is the second housing, 26 is the bearing, 27 is the shaft, 28 is the second rotor, 29 Is a state, 30 is a coil, 31 is an armature, 32 is an encoder, 41 is a first stage, 42 is a second stage, 43 is a hand for holding a wafer, and 43 is an armature holder. Is shown.

[Best Mode for Carrying Out the Invention]

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]

FIG. 1 is a side sectional view of a reducer motor according to a first embodiment of the present invention, FIG. 2 is a front sectional view thereof, and FIG. 3 is an operation explanatory view.

As shown in FIGS. 1 and 2, in the first embodiment, a vacuum chamber wall (hereinafter, referred to as a chamber wall) 5 is provided on the atmosphere side through a linear guide 6 which is a sliding portion. The first field yoke 1 is slidably arranged, and a plurality of first field magnets 7 are arranged in the longitudinal direction of the first field yoke 1 so that the polarities are alternately different. A first mover 8 is constituted by the first field yoke 1 and the first field magnet 7.

On the other hand, the second field yoke 2 is slidably disposed on the vacuum side of the champ wall 5 via a linear guide 9 which is a sliding portion, and the polarity is alternately different in the longitudinal direction of the second field yoke 2. A plurality of second field magnets 10 are arranged as described above. The second mover 11 is constituted by the second field yoke 2 and the second field magnet 10. On the atmosphere side of the champ wall 5, there is provided a stator including an armature 3 which is arranged to face the first field magnet 7 via a magnetic gap.

A magnetic sensor 4 for detecting a thrust-direction magnetic flux Bx and a gap-direction magnetic flux Bz is provided on the first movable arm 8 as a phase difference detecting means for detecting a relative phase difference with the second movable element 11. Installed. Further, the first mover 8 is provided with an encoder including a sensor head 12 and a linear scale 13 for detecting the position of the first mover 8 in the slide direction with respect to the vacuum champer.

In addition, rolling bearings are used as the linear guides 6 and 9 which are sliding portions of the linear motor.

The inner ring, outer ring, and balls of the rolling bearing are made of iron-based metal materials such as SUJ2 and SUS440C. Of these, the inner ring of the rolling bearing arranged on the vacuum side and the outer ring facing it are All or some of the sliding surfaces of the balls inserted between the V-shaped transfer grooves provided on each surface of the inner ring and the outer ring have a thin film of solid lubricant such as molybdenum disulfide, tungsten disulfide, silver, etc. Is formed using a sputtering process or the like.

In this way, by using a rolling bearing with a solid lubricant coating on the sliding part of a linear motor in a vacuum, the life of the bearing can be prolonged, and the effect of contamination due to scattering of particles from the bearing into the vacuum can be achieved. Can also be prevented. Next, the operation of the lower motor according to the first embodiment will be described.

When an AC current having a predetermined phase, frequency and amplitude is applied to the armature 3 provided on the atmosphere side of the chamber wall 5 based on the position command from the host controller (not shown) and the position information of the linear scale 13, the gap The first field yoke 1 arranged via the switch operates following the command. At this time, the second field yoke 2 arranged in the vacuum champ also operates following the current of the armature 3 and the magnetic flux of the first field yoke 1. As shown in FIG. 3 (a), when the first field yoke 1 and the second field yoke 2 are operating without any positional displacement, the magnetic flux in the thrust direction of the magnetic sensor 4 is ideally 0. Become. As shown in FIG. 3 (b), when the load on the second field yoke 2 is large and a positional displacement with the first field yoke 1 occurs, the magnetic flux BX in the thrust direction of the magnetic sensor 4 increases. Therefore, the signal of the magnetic sensor 4 is input to the host controller and The position control of the second field yoke 2 in the vacuum chamber is performed by correcting the position command through a control unit that does not perform the control.

As described above, a rear air motor can be formed with a structure in which only the second mover 11 and the linear guide 9 are provided in the vacuum chamber.

Therefore, no wiring is required in the vacuum chamber, and the position information of the second field yoke 2 is also fed back by the magnetic sensor 4, so that there is no risk of loss of synchronism, and particles and gas generation are small. In addition, since a cooling device can be dispensed with as compared with the conventional vacuum linear motor, there is an effect that the configuration is simplified.

Further, as described above, the empty linear guide 9 disposed in the vacuum chamber is a rolling bearing, and at least all or some of the rolling surfaces of the inner ring, the outer ring, and the balls of the rolling bearing are provided with at least one rolling surface. By forming a solid lubricant film composed of molybdenum disulfide, tungsten disulfide or silver, the generation of particles can be further suppressed.

In the present embodiment, an example in which a magnetic sensor is used as the phase difference detecting means has been described, but an optical sensor including a slit and a light emitting device and a light receiving device arranged so as to sandwich the slit is used. You can also.

[Second embodiment]

FIG. 4 is a sectional view of a rotary motor according to a second embodiment of the present invention. As shown in the figure, in the second embodiment, a sliding portion is attached to a first housing 21 provided on the atmosphere side of a vacuum chamber wall surface (hereinafter referred to as a chamber wall surface) 5 '. A shaft 23 is rotatably supported via a certain bearing 22, and a first rotor 24 is attached to the shaft 23. Permanent magnets are arranged in the circumferential direction of the first rotor 24 so that the polarities N and S are alternately different. A permanent magnet may be magnetized on the first rotor 24 itself.

On the other hand, a shaft 27 is rotatably supported by a second housing 25 provided on the vacuum side of the chamber wall surface 5, via a bearing 26 as a sliding portion. Two rotors 28 are installed. Permanent magnets are arranged in the circumferential direction of the second rotor 28 so that the polarities N and S are alternately different. 2nd row The permanent magnet may be magnetized on the tab 28 itself.

An armature 31 including a stator yoke 29 and a coil 30 is provided on the champer wall surface 5 ″, facing the first rotor 24 with a magnetic gap therebetween.

An encoder 32 for detecting the position of the first rotor 24 in the rotation direction with respect to the chamber wall surface 5 'is provided on the shaft 23 of the first rotor 24.

Although not shown, a magnetic sensor as a phase detecting means is provided at the air core of the coil 30.

Next, the operation of the rotary motor according to the second embodiment will be described.

Based on the position command from the host controller (not shown) and the position information of the encoder 32, the alternating current of a predetermined phase, frequency and amplitude is applied to the coil 30 of the armature 31 provided on the atmosphere side of the chamber wall 5 '. Is applied, the first port 24 arranged through the gap operates following the command. At this time, the second rotor 28 disposed in the vacuum chamber also operates following the current of the armature 31 and the magnetic flux of the first rotor 24.

When the first rotor 24 and the second rotor 28 operate without displacement, the magnetic flux in the thrust direction of the magnetic sensor is ideally zero. When the load on the second rotor 28 is large and a positional deviation from the first rotor 24 occurs, the magnetic flux in the thrust direction of the magnetic sensor increases. Therefore, the rotation position of the second rotor 28 in the vacuum chamber is controlled by inputting the signal of the magnetic sensor to the host controller and correcting the position command.

As described above, a rotary motor can be configured with a structure in which only the second rotor 28 and the bearing 26 are provided in the vacuum chamber.

Note that other configurations and modifications are the same as those of the first embodiment, and thus description thereof is omitted.

[Third embodiment]

FIGS. 5 and 6 show a substrate transfer apparatus according to a third embodiment of the present invention. FIG. 5 is a plan view thereof, and FIG. 6 is a front view thereof.

In these figures, 4 1 is the first stage, 4 2 is the second stage, 4 3 is ゥ The hand for holding the wafer, 44 is an armature holder.

In the substrate transfer device of the present embodiment, the linear motor of the first embodiment is used as the moving mechanism of the first stage 41, and the second embodiment is used for the rotating mechanism of the wafer gripping hand 43. Rotary motor is used. In this case, the armature 31 and the first housing 21 of the second embodiment are not fixed to the champ wall 5 but are fixed to the first mover 8 on the linear motor side by the armature holder 44. . Also, the second housing 25 is not provided, and the bearing 26 is attached to the second mover 11. In this embodiment, the second mover 11 of the linear motor and the second rotor 28 of the rotary motor are arranged on the vacuum side of the chamber wall 5, and the first mover 8 and the first rotor 24 are arranged on the atmosphere side. Is placed. Then, the first mover 8 and the first rotor 24 are driven in accordance with the position command, and the second mover 11 and the second rotor 28 are controlled so that there is no phase shift. Control is performed so that the mover 11 and the second rotor 28 are driven as instructed.

As a result, a port-wafer stage for transferring a substrate in a clean environment such as a wafer manufacturing apparatus can be realized with a configuration capable of significantly suppressing generation of particles and heat.

Although the optical encoder used in the present embodiment has been described as an example, a magnetic encoder may be used instead.

Further, the phase difference detecting means used in the present embodiment has been described using a magnetic sensor as an example, but a transmission type optical sensor may be used instead. When this optical sensor is applied, a light emitting unit and a light receiving unit are provided on the first movable element provided on the air side of the motor, and a transmission window for transmitting light emitted from the light emitting unit is provided on the wall of the vacuum chamber. And a reflector for reflecting light is provided on the second movable element provided on the vacuum side of the motor, and a phase difference caused by the movement of the first movable element and the second movable element is detected by the light receiving section. To detect.

[Industrial applicability]

As described above, the present invention is suitable for an apparatus for transferring a semiconductor wafer in a semiconductor manufacturing apparatus used in a process such as CVD (Chemical Vapor Deposition) for manufacturing a semiconductor element in a vacuum environment. What It is useful as an in-vacuum drive device and a substrate transfer device using the same.

Claims

The scope of the claims

1. a first movable element having a magnetic field, which is provided on the atmosphere side facing the wall surface of the vacuum champer and is movably disposed via a sliding portion;

A second movable element having a magnetic field movably disposed on the vacuum side via a sliding portion via a wall surface of the vacuum chamber,

A drive unit comprising a stator, which is fixed to the atmosphere side of the wall of the vacuum chamber and comprises an armature disposed opposite to the first mover via a magnetic gap;

An encoder provided on the first mover for detecting a position of the first mover in a moving direction with respect to the vacuum chamber;

Phase difference detecting means provided on the first mover, for detecting a phase shift between the first mover and the second mover,

Power is supplied to the armature so as to match a position command of the first mover detected by the encoder with respect to a position command signal, and a phase difference detected by the phase difference detection means is suppressed. A drive means for correcting the position command signal as described above.

2 · The drive unit is composed of a linear motor,

The field of the first mover is a plate-shaped first field yoke and a first field magnet in which a plurality of magnetic poles are arranged so that the polarities are alternately different in the longitudinal direction of the first field yoke. Consists of

The field of the second mover is composed of a plate-shaped second field yoke and a second field magnet in which a plurality of magnetic poles are arranged so that the polarities are alternately different in the longitudinal direction of the second field yoke. Consists of

2. The in-vacuum drive device according to claim 1, wherein the armature is configured by an armature coil including a plurality of smooth coil groups.

3. The drive unit is composed of a rotary motor,

The field of the first mover is constituted by a disk-shaped first field magnet having a plurality of magnetic poles formed so that the polarities are alternately different in a circumferential direction,

The field of the second mover is formed by a plurality of magnetic fields such that the polarities are alternately different in the circumferential direction. It is composed of a disc-shaped second field magnet with poles,

2. The in-vacuum drive device according to claim 1, wherein the armature is configured by an armature coil including a plurality of ring-shaped coil groups.

4. The vacuum drive apparatus according to claim 1, wherein a magnetic sensor that detects a magnetic flux in a thrust direction and a magnetic flux in a gap direction is used as the phase difference detecting unit.

5. The in-vacuum drive device according to any one of claims 1 to 3, wherein a transmission type optical sensor is used as the phase difference detection means.

6. The encoder includes an optical linear scale disposed on the atmosphere side of a wall surface of the vacuum chamber, and a sensor disposed on the first mover opposite to the optical linear scale to detect the linear scale. 3. The in-vacuum drive device according to claim 2, wherein the drive device is an optical encoder including a head.

7. A rolling bearing is provided on the sliding part, and all or some of the sliding surfaces of the inner ring, outer ring and ball of the rolling bearing arranged on the vacuum side are molybdenum disulfide, tungsten disulfide or silver. 7. The in-vacuum drive device according to claim 1, wherein a thin film of at least one solid lubricant is formed.

8.Using the in-vacuum drive device comprising the drive unit according to any one of claims 1 to 7, further comprising a transfer unit for transferring a wafer substrate by the second movable element. Substrate transfer device.