JP4363064B2 - In-vacuum drive device and substrate transfer device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an in-vacuum driving apparatus suitable for an apparatus for carrying 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, and the like. The present invention relates to the substrate transfer device used.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a device for transporting a semiconductor wafer in a semiconductor manufacturing apparatus used in a process such as CVD (Chemical Vapor Deposition) for manufacturing a semiconductor element, for example, a motor as a driving source thereof is driven in a vacuum environment. . Equipment used in this clean vacuum environment is required to generate less gas and particles and to increase temperature. This is because the generation of gas and particles reduces the required cleanliness, and the temperature rise adversely affects the manufacturing process of temperature-controlled semiconductors and the like.
[0003]
Conventionally, as an example of driving a linear motor in a vacuum, for example, as disclosed in Patent Documents 1 and 2, a canned linear motor that directly cools an armature winding of an armature with a refrigerant has been proposed. ing. The canned linear motor includes a movable coil type having an armature as a mover and a field as a stator (Patent Document 1), and a movable magnet type having a field as a mover and an armature as a stator. (Patent Document 2). Of these, FIG. 7 shows a moving coil type. FIG. 7 is a perspective view showing the entire conventional moving 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 discharge port, 56 is a cable for feeding and signals, 57 is a stator, and 58 is a stator base. 59 is a field yoke, and 60 is a field magnet.
The mover 51 has a T-shape, a mover base 52, a can 53 supported downward on the mover base 52, a header (not shown) that seals the can 53, A winding fixing frame (not shown) provided in the space formed by the can 53 and the header, a coreless type three-phase armature winding (not shown) fixed to the winding fixing frame, and the can And a refrigerant passage (not shown) that passes through.
The mover 51 is supported by a linear guide or the like (not shown). Then, the mover 51 is provided with a refrigerant supply port 54 and a refrigerant discharge port 55 for allowing the refrigerant to pass through. The refrigerant is supplied from the refrigerant supply port 54 and discharged from the refrigerant discharge port 55, whereby the refrigerant is The refrigerant flows between the slave winding and the can 53.
The stator 57 includes a field magnet 60 disposed so as to face the armature portion through a magnetic yap, and a flat field yoke 59 that holds the field magnet 60. Yes.
As shown in FIG. 7, the canned linear motor has a power line for supplying power to the armature coil, a cable 56 such as a signal line for the position sensor, or a cooling pipe (not shown) provided in the vacuum chamber. It is pulled out through the vacuum chamber.
By flowing a predetermined current through the armature winding of the armature with such a configuration, it acts on the magnetic field created by the field magnet 60, generates thrust on the mover 51, and can move in the traveling direction indicated by the arrow. It has become. And the armature winding which generate | occur | produced by the copper loss is cooled with a refrigerant | coolant, and the temperature rise of the needle | mover surface is suppressed low.
In addition, as a countermeasure against gas generation, there is one in which the field portion of the linear motor is plated with Ni or Cu (for example, Patent Document 3).
[0004]
[Patent Document 1]
JP 2001-238428 A [Patent Document 2]
Japanese Patent Application No. 2001-367067 [Patent Document 3]
Japanese Patent Laid-Open No. 8-107665
[Problems to be solved by the invention]
However, in such a conventional structure, a cable such as a power line or a signal line is covered with a synthetic resin, so that it is necessary to take measures against gas generation and to take measures against cooling the heat generating portion.
When the linear motor is a moving coil type, the moving coil is arranged in the vacuum chamber, so the motor lead wires, signal wires, and cooling pipes are routed in the vacuum chamber. Inevitable.
Also, when the linear motor is a movable magnet type, it is necessary to provide a linear scale with the stroke + length of the mover on the mover side, or to provide a sensor head on the mover side and route the signal line. Particles from the line are generated.
Moreover, since the linear motor requires a cooling device, the configuration becomes complicated.
[0006]
The present invention has been made to solve the above-described problems, and does not generate particles without routing motor lead wires, signal wires, cooling pipes, and the like in a vacuum chamber, and has a simple configuration. It is an object of the present invention to provide a driving device and a substrate transfer device using the same.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a vacuum driving device according to the first aspect of the present invention is provided on the atmosphere side facing the wall surface of the vacuum chamber, and is movably disposed via a sliding portion, and has a flat plate shape. A first mover having a field composed of a 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 ; The second chamber yoke and the second field yoke have different polarities alternately in the longitudinal direction, and are movably disposed on the vacuum side through the sliding portion through the wall surface of the vacuum chamber. A second mover having a field composed of a second field magnet having a plurality of magnetic poles, and fixed to the atmosphere side of the wall surface of the vacuum chamber, with the first mover interposed through a magnetic gap is opposed Te, electrodeposition comprising a plurality of coil groups of the smooth type And has been driven unit consists of more becomes a linear motor and a stator consisting configured armature in the child coils, provided in the first movable element, detects a position of the moving direction of the first movable element relative to the vacuum chamber And a phase difference detecting means provided on the first mover for detecting a phase shift between the first mover and the second mover. Control for supplying power to the armature so as to coincide with the detected position command of the first armature and correcting the position command signal so as to suppress the phase difference detected by the phase difference detecting means characterized in that a means.
[0008]
In the vacuum driving apparatus according to the first aspect, when a position command is input from a host controller or the like, electric 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 field of each of the first and second movers, the first and second movers move in a predetermined direction. The control means controls the electric power supplied to the armature so that the position of the first mover detected by the encoder matches the position command. If the phase shift in the thrust direction between the first movable element and a second movable element occurs, since the phase difference detector output is activated in response to the phase shift, the position command signal so as to suppress the phase shift By correcting, the second mover is controlled to coincide with the position command.
Since only the second movable element and the sliding portion are arranged inside the vacuum chamber, and the armature having the lead wire, the phase difference detecting means with wiring, and the encoder are arranged outside the vacuum chamber, the vacuum chamber The generation of particles inside is significantly reduced.
[0009]
The invention according to claim 2 is characterized in that a magnetic sensor for detecting thrust direction magnetic flux and gap direction magnetic flux is used for the phase difference detecting means.
In the second aspect, the phase shift between the first movable element and a second movable element is detected as a change in the thrust direction magnetic flux.
The invention according to claim 3 is characterized in that a transmissive optical sensor is used for the phase difference detecting means.
In the third aspect, the phase shift between the first movable element and a second movable element is output as a change in the duty ratio of the output of the optical sensor.
[0010]
According to a fourth aspect of the present invention, the encoder includes an optical linear scale disposed on the atmosphere side of the wall surface of the vacuum chamber, and the first movable element facing the optical linear scale. An optical encoder comprising a sensor head for detecting the linear scale.
According to the fourth aspect of the present invention, a relative position change between the wall surface of the vacuum chamber and the first mover is detected by the sensor head and fed back to the control means as a position signal.
[0011]
According to a fifth aspect of the present invention, there is provided a substrate transfer apparatus comprising: a transfer unit configured to transfer a wafer substrate by the second mover using the in-vacuum drive device including the drive unit according to any one of the first to fourth aspects. It is characterized by having.
According to the fourth aspect of the present invention, a robot, a wafer stage, or the like carrying means for carrying a wafer substrate using a second mover arranged in a vacuum by combining one or more of the in-vacuum driving devices. Can be realized.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
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 thereof, and FIG.
[0013]
As shown in FIGS. 1 and 2, in the first embodiment, a linear guide 6 that is a sliding portion is provided on the atmosphere side of a wall surface (hereinafter referred to as a chamber wall surface) 5 of a vacuum chamber. A first field yoke 1 is slidably disposed, and a plurality of first field magnets 7 are disposed so that the polarities are alternately different in the longitudinal direction of the first field yoke 1. The first field yoke 1 and the first field magnet 7 constitute a first mover 8.
[0014]
On the other hand, the second field yoke 2 is slidably disposed on the vacuum side of the chamber wall surface 5 via a linear guide 9 that is a sliding portion, and the polarities are 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 field yoke 11 and the second field magnet 10 constitute a second mover 11.
[0015]
On the atmosphere side of the chamber wall surface 5, there is provided a stator composed of the armature 3 disposed to face the first field magnet 7 with a magnetic gap interposed therebetween.
A magnetic sensor 4 for detecting the thrust direction magnetic flux Bx and the gap direction magnetic flux Bz is attached to the first mover 8 as a phase difference detection means for detecting a relative phase difference with the second mover 11. 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 sliding direction with respect to the vacuum chamber.
[0016]
Further, rolling bearings are used as the linear guides 6 and 9 which are sliding portions of the linear motor.
The material of the inner ring, outer ring and ball of the rolling bearing is a ferrous metal material such as SUJ2 or SUS440C. Among these, the inner ring of the rolling bearing arranged on the vacuum side and the outer ring facing the inner ring, the inner ring and the outer ring, respectively. A thin film of a solid lubricant such as molybdenum disulfide, tungsten disulfide, or silver is applied to the sliding surface of all or part of the ball inserted between the V-shaped transfer grooves provided on the surface of the surface by sputtering or the like. Form.
By using a rolling bearing with a solid lubricant coating on the sliding part of a linear motor in a vacuum in this way, the bearing life can be extended and the effects of contamination caused by scattering of particles from the bearing into the vacuum can be increased. Can also be prevented.
[0017]
Next, the operation of the linear motor according to the first embodiment will be described.
When an alternating current having a predetermined phase, frequency, and amplitude is applied to the armature 3 provided on the atmosphere side of the chamber wall surface 5 based on the position command from the host controller (not shown) and the position information of the linear scale 13, The arranged first field yoke 1 operates following the command. At this time, the second field yoke 2 disposed in the vacuum chamber also operates following the current of the armature 3 and the magnetic flux of the first field yoke 1.
As shown in FIG. 3A, when the first field yoke 1 and the second field yoke 2 are operating without causing a positional shift, the thrust direction magnetic flux of the magnetic sensor 4 is ideally 0. Become. As shown in FIG. 3B, when the load on the second field yoke 2 is large and a positional deviation from the first field yoke 1 occurs, the thrust direction magnetic flux Bx of the magnetic sensor 4 increases. Therefore, the position of the second field yoke 2 in the vacuum chamber is controlled by inputting the signal of the magnetic sensor 4 to the host controller and correcting the position command via a control means (not shown).
[0018]
As described above, a linear motor can be formed with a structure in which only the second movable element 11 and the linear guide 9 are disposed in the vacuum chamber.
Therefore, no wiring is required in the vacuum chamber, and the position information of the second field yoke 2 is fed back by the magnetic sensor 4, so there is no risk of step-out and there are few particles and gas generation. Further, since a cooling device can be made unnecessary as compared with the conventional vacuum linear motor, there is an effect that the configuration is simplified.
[0019]
Furthermore, as described above, the linear guide 9 on the vacuum side arranged in the vacuum chamber is a rolling bearing, and at least molybdenum disulfide on the sliding surfaces of all or part of the inner ring, outer ring and ball of the rolling bearing, By forming a thin film of solid lubricant made of tungsten disulfide or silver, the generation of particles can be further suppressed.
In this embodiment, an example is shown in which a magnetic sensor is used as the phase difference detection means. However, an optical sensor comprising a slit and a light emitter and a light receiver arranged so as to sandwich the slit may be used. it can.
[0020]
< Reference example >
FIG. 4 is a cross-sectional view of a rotary motor according to a reference example .
As shown in the figure, in this reference example , a bearing 22 as a sliding portion is provided on a first housing 21 provided on the atmosphere side of a wall surface (hereinafter referred to as a chamber wall surface) 5 ′ of a vacuum chamber. A shaft 23 is rotatably supported through the first rotor 24. 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.
[0021]
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 that is a sliding portion, and a second rotor 28 is attached to the shaft 27. It has been. Permanent magnets are arranged in the circumferential direction of the second rotor 28 so that the polarities N and S are alternately different. A permanent magnet may be magnetized on the second rotor 28 itself.
[0022]
The chamber wall surface 5 ′ is provided with an armature 31 including a stator yoke 29 and a coil 30 that are disposed to face the first rotor 24 with a magnetic gap therebetween.
The shaft 23 of the first rotor 24 is provided with an encoder 32 that detects the position of the first rotor 24 in the rotational direction with respect to the chamber wall surface 5 ′.
A magnetic sensor as the phase detection means is not shown, but is provided in the air core of the coil 30.
[0023]
Next, the operation of the rotary motor according to this reference example will be described.
When an alternating current having 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 surface 5 ′ by a position command from a host controller (not shown) and position information of the encoder 32, a gap is generated. The first rotor 24 arranged via the motor 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 positional deviation, 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 shift with the first rotor 24 occurs, the magnetic flux in the thrust direction of the magnetic sensor increases. Therefore, the rotational position control of the second rotor 28 in the vacuum chamber is performed by inputting the magnetic sensor signal 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 disposed in the vacuum chamber.
Other configurations and modifications are the same as those in the first embodiment, and thus description thereof is omitted.
[0024]
<Second Embodiment>
5 and 6 show a substrate transfer apparatus according to a second embodiment of the present invention. FIG. 5 is a plan view thereof, and FIG. 6 is a front view thereof.
In these drawings, 41 is a first stage, 42 is a second stage, 43 is a wafer gripping hand, and 44 is an armature holder.
In the substrate transfer apparatus of the present embodiment, the linear motor of the first embodiment is used as the moving mechanism of the first stage 41, and the rotary motor of the reference example is used as the rotating mechanism of the wafer gripping hand 43. Yes. In this case, the armature 31 and the first housing 21 of the reference example are not fixed to the chamber wall surface 5 but are fixed to the first movable element 8 side on the linear motor side by the armature holder 44. Further, the second housing 25 is not provided, and the bearing 26 is attached to the second mover 11.
[0025]
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 surface 5, and the first mover 8 and the first rotor 24 are arranged on the atmosphere side. ing. Then, the first movable element 8 and the first rotor 24 are driven according to the position command, and the second movable element 11 and the first rotor 24 are controlled by controlling the second movable element 11 and the second rotor 28 so as to eliminate the phase shift. 2. Control so that the rotor 28 is driven as instructed.
Thereby, it is possible to realize a robot and a wafer stage for transporting a substrate in a clean environment such as a wafer manufacturing apparatus with a configuration capable of significantly suppressing generation of particles and generation of heat.
The encoder used in this embodiment has been described by taking an optical encoder as an example, but a magnetic encoder may be used instead.
The phase difference detection means used in the present embodiment has been described by taking a magnetic sensor as an example. However, instead of this, a transmission type optical sensor may be used. When this optical sensor is applied, a light emitting part and a light receiving part are provided on the first mover provided on the atmosphere side of the motor, and a transmission window for transmitting light emitted from the light emitting part is provided on the wall surface of the vacuum chamber. In addition, a reflector plate for reflecting light is provided on the second movable element provided on the vacuum side of the motor so that a phase difference caused by the movement of the first movable element and the second movable element is detected by the light receiving unit. To.
[0026]
【The invention's effect】
As described above, according to the vacuum driving apparatus of the present invention, only the second movable element and the sliding portion are arranged on the vacuum side of the wall surface of the vacuum chamber, and the second movable element is arranged on the atmosphere side of the vacuum chamber wall surface. Since the first armature, the armature, the phase difference detection means and the encoder are controlled so as to match the position command, there is no wiring in the vacuum chamber, and gas and particles are generated in the vacuum chamber. Can be significantly reduced. Further, since the motor cooling device can be omitted, there is an effect that the configuration is simplified .
[0027]
Further, according to the substrate transfer apparatus of the present invention, by combining one or more vacuum drive device realized as a linear motors, with a second movable element which is placed in a vacuum, the wafer substrate It is possible to realize a substrate transfer apparatus including transfer means such as a robot for transferring the wafer and a wafer stage. Also in this substrate transfer apparatus, there is no wiring in the vacuum chamber, and generation of gas and particles in the vacuum chamber can be remarkably reduced.
[Brief description of the 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 the linear motor according to the first embodiment.
FIG. 3 is an operation explanatory diagram of the linear motor according to the first embodiment.
FIG. 4 is a cross-sectional view of a rotary motor according to a reference example .
FIG. 5 is a plan view of a substrate transfer apparatus according to a second embodiment of the present invention.
FIG. 6 is a front view of a substrate transfer apparatus according to a second embodiment.
FIG. 7 is a perspective view showing a configuration of a conventional canned linear motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st field yoke 2 2nd field yoke 3 Armature 4 Magnetic sensor 5, 5 'Chamber wall surface 6 Linear guide 7 First field magnet 8 First mover 9 Linear guide 10 Second field magnet 11 2nd Movable element 12 Sensor head 13 Linear scale 21 First housing,
22 Bearing 23 Shaft 24 First rotor 25 Second housing 26 Bearing 27 Shaft 28 Second rotor 29 Stator yoke 30 Coil 31 Armature 32 Encoder 41 First stage 42 Second stage 43 Wafer gripping hand 44 Armature holder

Claims (5)

Provided on the atmosphere side facing the wall surface of the vacuum chamber and arranged to be movable through a sliding portion , the polarities are alternately arranged in the longitudinal direction of the flat plate-like first field yoke and the first field yoke. A first mover having a field composed of a first field magnet having a plurality of magnetic poles arranged differently ;
A plurality of the second field yoke and the second field yoke are arranged so as to be alternately movable in the longitudinal direction of the flat second field yoke and the second field yoke. A second mover having a field composed of a second field magnet in which a plurality of magnetic poles are arranged ;
A stator composed of an armature fixed to the atmosphere side of the wall surface of the vacuum chamber and arranged to face the first mover via a magnetic gap and composed of armature coils composed of a plurality of smooth coil groups. A drive unit composed of a linear motor comprising :
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;
A phase difference detecting means provided on the first mover for detecting a phase shift between the first mover and the second mover;
Electric power is supplied to the armature so as to match the position command of the first mover detected by the encoder with respect to the position command signal, and the phase difference detected by the phase difference detecting means is suppressed. An in-vacuum drive device characterized by further comprising a control means for correcting the position command signal. Wherein the phase difference detecting means, the vacuum within the drive apparatus according to claim 1, characterized by using a magnetic sensor for detecting a thrust magnetic flux and the gap magnetic flux. The phase difference detecting means, the vacuum within the drive apparatus according to claim 1, characterized by using an optical sensor of transmission type. The encoder includes an optical linear scale disposed on the atmosphere side of the wall surface of the vacuum chamber, and a sensor head disposed on the first movable element so as to face the optical linear scale and detect the linear scale. it is an optical encoder composed of a vacuum drive apparatus according to claim 1, wherein. Substrate using a vacuum within the drive device consisting of the drive unit according to any one of claims 1-4, characterized by comprising conveying means for conveying the wafer substrate by the second movable element Conveying device.

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