JP2003191140A - Positioning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positioning device capable of enhancing bearing rigidity without making the device to a large size. <P>SOLUTION: The positioning device positions a moving stage 102 supported by a fluid bearing 103 against a base 101 and is provided with a driving magnet 104 adding force so as to move the moving stage to a direction perpendicular to a pressure surface receiving a fluid pressure of the fluid bearing 103; a target member 107 integrally moved to a moving direction with the moving stage and relatively movably supported against the moving stage in the direction perpendicular to the pressure surface; and a detection sensor 106 for detecting a relative position in the direction perpendicular to the pressure surface of the moving stage and the target member. A bearing gap of the moving stage is controlled by adjusting generation force of the driving magnet based on a detection result of the detection sensor. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning device for highly accurately positioning a moving stage used in a precision processing machine such as a cutting machine, a grinding machine, a polishing machine or the like, a semiconductor manufacturing apparatus or the like which requires precise accuracy. It is about.

[0002]

2. Description of the Related Art Conventionally, a positioning device using a fluid bearing as a guide has a driving means (a characteristic of non-contact support of the fluid bearing is used) for applying a thrust force in a moving direction of a moving stage having a fluid bearing. Used),
Positioning control of the moving stage is provided by a measuring unit that measures the position of the moving stage and a control unit that adjusts the thrust generated by the driving unit based on the position feedback signal detected by the measuring unit.

The rigidity of the moving stage in such a positioning device is determined by the control characteristics of the position feedback control system in the moving direction, and by the bearing rigidity of the fluid bearing in the direction orthogonal to the moving direction.
As a method for improving the bearing rigidity, there is a method of increasing the size of the moving stage, such as increasing the area of the bearing or increasing the pressure of the supplied fluid.

Further, as a method for avoiding an increase in size of the apparatus,
A thrust generating means for generating a thrust in the bearing gap direction and a displacement detecting means for detecting the displacement between the moving stage and the guide, that is, the bearing gap are provided, and the displacement (gap) between the moving stage and the guide detected by the displacement detecting means is provided. There is a method of controlling the displacement (gap) between the moving stage and the guide to be constant by feeding back and adjusting the thrust of the thrust generating means.

[0005]

However, in the method of increasing the bearing rigidity by feeding back the bearing gap displacement shown in the prior art, the guide face is measured from the moving stage to detect the bearing gap displacement. If scratches and dust are attached and the scratches and dust are detected by the displacement detection means, it is determined that the bearing gap displacement has changed, and a malfunction occurs.

Further, in order to realize a stable operation even if there are scratches and dust, the thrust generating means must also have a large thrust force capable of correcting the error displacement detected by the scratches and dust.

Therefore, in order to operate stably as a positioning device, it is necessary to pay close attention not to scratch or dust the guide, and at the same time, a special installation environment such as a clean room is required. There was a problem that it became difficult to handle.

Therefore, the present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a positioning device capable of increasing the bearing rigidity without increasing the size of the device.

[0009]

[Means for Solving the Problems]
In order to achieve the object, a positioning device according to the present invention is a positioning device for positioning a moving stage supported by a fluid bearing with respect to a base, and a pressure surface for receiving a fluid pressure of the fluid bearing. A driving unit that applies a force to move the moving stage in a vertical direction and the moving stage moves integrally with the moving stage in the moving direction of the moving stage, and the moving stage moves in a direction perpendicular to the pressure surface. A target member that is supported so as to be movable relative to the base member, support means that supports the target member with respect to the base through a fluid in a direction perpendicular to the pressure surface, the moving stage and the target member. Detecting means for detecting a relative position in a direction perpendicular to the pressure surface, and generating the drive means based on the detection result of the detecting means. It is characterized by controlling the bearing gap of the movable stage by adjusting the.

In the positioning device according to the present invention, the target member is supported by the base through a fluid and is attracted to the base by a magnet, so that the pressure of the fluid is It is characterized in that a predetermined distance from the base is maintained by balancing the attractive force of the magnets.

Further, in the positioning device according to the present invention, the target member is supported by the fluid stage with respect to the moving stage.

Further, in the positioning apparatus according to the present invention, the target member is supported by the moving stage by a leaf spring.

Further, in the positioning device according to the present invention, the driving means includes an electromagnet.

Further, in the positioning device according to the present invention, the driving means is provided with a fluid bearing and a piezoelectric element for moving the fluid bearing in a direction perpendicular to a pressure surface thereof.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing the structure of a moving stage in a positioning apparatus according to an embodiment of the present invention. 2 is a diagram showing a configuration of an XY stage incorporating the structure shown in FIG. 1, and FIG. 3 is a diagram showing a characteristic structure of the XY stage shown in FIG. FIG. 4 is a block diagram showing the configuration of a control system for controlling the XY stage shown in FIG.

In FIG. 1, 101 is a guide, 102 is a moving stage, and 103 is a fluid bearing, which supports the moving stage 102 from the guide 101 by a supplied fluid in a non-contact manner. An electromagnet 104 generates thrust in the bearing gap direction (Z direction in the coordinate system of FIG. 1).

Reference numeral 105 is a displacement detector holder attached to the moving stage 102, 106 is a displacement detector, and 107 is a target member for detecting the displacement in the bearing gap direction by the displacement detector 106, which faces the guide 101. A fluid bearing 108 and a pressurizing magnet 109 are arranged in the.

Reference numeral 110 denotes a fluid bearing incorporated in the displacement detector holder 105, which supports the target member 107 with respect to the moving stage 102 in the XY plane in the coordinate system of FIG. The moving stage 102 is supported in the Z direction by the fluid bearing 103 in a non-contact manner from the guide 101, and can be smoothly moved in the XY directions.

The target member 107 is the moving stage 10
The displacement detector holder 105 fixed to No. 2 is supported by the fluid bearing 110 in the XY directions. At the same time, the target member 107 has the fluid bearing 108 and the pressurizing magnet 109 arranged on the side facing the guide 101, and the force of the levitation force generated by the fluid bearing 108 and the suction force by the pressurizing magnet 109 is caught by the guide 101. It is held in a fixed bearing gap that is determined by the combination. Therefore, when the moving stage 102 moves in the XY plane, the target member 107 moves along with the moving stage 102 in the XY coordinate directions and follows the surface of the guide 101 in the Z direction. By detecting the displacement of the target member 107 in the Z direction from the moving stage 102, the bearing gap displacement of the moving stage 102 can be detected.

In FIG. 1, the electromagnet 104 is based on the displacement of the target member 107 in the Z direction detected by the displacement detector 106.
By adjusting the thrust generated in the moving stage 102
It is possible to control the displacement in the Z direction.

2 and 3 show the configuration of one embodiment of the XY stage.

In FIGS. 2 and 3, 201 is a base platen which serves as a guide in the Z direction in the coordinate system of FIG.
a and 202b are Y-direction guides for the X stage, which will be described later.
03a and 203b are linear motor stators that generate thrust in the X direction, 204a and 204b are linear motor movers, and 205a and 205b (205b is not shown) are positioned by the laser length measuring device in the X direction. A measurement mirror for measurement, 206a and 206b are connecting plates that connect the linear motor movers 204a and 204b to the X stage, and 207 is an X that also serves as a Y stage guide described later.
One member of the stage, 208a, 208b (208a is not shown) constitutes the X stage together with the member 207, 209a, 209b are linear motor stators 210a, 210b for generating thrust in the Y direction. Is a linear motor mover that generates thrust in the Y direction, 21
Reference numerals 1a and 211b (211b is not shown) are measuring mirrors for measuring a position in the Y direction by a laser length measuring machine, and 212a, 212b, 212c and 212d are displacements in the Z direction fixed to a Y stage described later. A displacement detector 213 for detection is a Y stage, 214a, 214
b, 214c, 214d (214b, 214c are not shown) are displacement detectors 212a, 212b, 212.
It is a target member corresponding to the target member 107 shown in FIG. 1 in which the displacement in the Z direction is detected by c and 212d.

In FIG. 2, members 207 and 208 are shown.
The X stage composed of a and 208b is a base surface plate 2
01 and X guides 202a and 202b are supported by fluid bearings in a non-contact manner. And the stator 203
A thrust force for moving in the X direction is given by the linear motor configured by a and the mover 204a and the linear motor configured by the stator 203b and the mover 204b.

The displacement moved by the applied thrust is detected by measuring the measuring mirrors 205a and 205b with a laser length measuring device. Similarly, the Y stage 213 is supported from the base surface plate 201 and the Y guide / X stage member 207 by fluid bearings in a non-contact manner. A linear motor including a stator 209a and a mover 210a, and a stator 2
A thrust force for moving in the Y direction is applied by a linear motor configured by 09b and a mover 210b, and displacement is detected by measuring the measurement mirrors 211a and 211b with a laser length measuring device.

Further, the displacement detectors 212a, 212b,
212c and 212d, the target member 21 shown in FIG.
The Z-direction displacements of 4a, 214b, 214c, and 214d are detected. Target members 214a, 214b, 214
c and 214d have the same structure as the target member 107 shown in FIG. Further, although not shown, electromagnets corresponding to the electromagnet 104 shown in FIG. 1 are provided at the bottom of the Y stage with displacement detectors 212a, 212b, 212c, 212.
They are arranged in the same number as d and generate thrust in the Z direction.

FIG. 4 is a diagram showing the configuration of a control device for controlling the XY stage shown in FIG.

In FIG. 4, 401 is a position command in the moving direction of the X stage, 402 is a subtracter for obtaining a position deviation from the position command 401 and the position signal fed back, 4
Reference numeral 03 is a PID compensator for adjusting the feedback control system at the X-direction position in the moving direction, reference numeral 404 is a filter for adjusting the feedback control system together with the PID compensator 403, and 4
Reference numeral 05 is a tilt angle command around the Z coordinate of the X stage, 406 is a subtracter for obtaining a deviation from the tilt angle command 405 and the tilt angle signal fed back, and 407 is a PID for adjusting the feedback control system of the tilt angle around the Z axis. Compensator, 408
Is a filter for adjusting feedback control in combination with the PID compensator 407, and 409 is a thrust force applied to the X stage from two feedback control systems including a position feedback control system in the moving direction of the X stage and a tilt angle feedback control system around the Z axis. The thrust distributors that calculate the thrust commands to the two linear motors that give the electric current, 410a and 410b are current amplifiers that amplify the thrust commands output from the thrust distributor 409 and drive the linear motors, and 411a and 411b are both ends of the X stage. The provided linear motor, 412 is an X stage,
Laser length measuring devices 413a and 413b measure the position in the X-axis direction of a measuring mirror mounted near the linear motor of the X stage, and 414 laser measuring devices 413a and 413.
The axis converter 415, which calculates the position of the X stage in the X direction and the tilt angle about the Z axis from the position detected by b, represents the position feedback signal 416 obtained from the axis converter 414 in the movement direction of the X direction. It is a feedback signal of the tilt angle around the Z axis obtained from the axis converter 414.

Reference numeral 417 is a position command in the moving direction of the Y stage, 418 is a subtracter for calculating a deviation from the position command 417 and a position signal fed back, and 419 is a PI for adjusting a position feedback control system in the moving direction of the Y stage.
D compensator, 420 is a filter that adjusts the feedback control system together with PID compensator 419, 421 is a tilt angle command about the Z axis of the Y stage, and 422 is a tilt angle and tilt angle command 421 about the Z axis to be fed back. A subtracter 423 for obtaining the deviation from and a reference numeral 423 is a PID compensator for adjusting a feedback control system for controlling the tilt angle around the Z axis,
424 is a filter for adjusting a feedback control system that controls the tilt angle around the Z axis in combination with the PID compensator 423, and 425 is a position feedback control system in the Y stage movement direction and a tilt angle feedback control system around the Z axis.
Thrust distributors 426a and 426b for calculating thrust commands from the two feedback control systems to the two linear motors provided at both ends of the Y stage are currents for amplifying the thrust commands output from the thrust distributor 425 and driving the linear motors. Amplifiers 427a and 427b are linear motors that give thrust of the Y stage, 428 is a Y stage, 429a and 429b.
Is a laser length-measuring device that measures the position in the Y-direction moving direction with a measuring mirror attached near the linear motor of the Y-stage, and 430 is a position in the Y-direction moving direction from the position detected by the laser length-measuring devices 429a and 429b. An axis converter 431 for calculating the tilt angle about the axis is an axis converter 43.
The Y stage movement direction feedback signal 432 output by 0 is the tilt angle feedback signal about the Z axis obtained from the axis converter 430.

433 is a Z direction position command of the Y stage,
434 is a subtracter that calculates a deviation from the position command 433 and the Z direction displacement signal fed back, 435 is a PID compensator that adjusts a feedback control system that controls the Z direction displacement of the Y stage, and 436 is a PID compensator 435. A filter for adjusting a feedback control system for controlling the displacement in the Z direction, 437 is a tilt angle command of the Y stage about the X axis, and 438 is a deviation from the fed back tilt angle about the X axis and the tilt angle command 437. Subtractor, 43
9 is a PID compensator that adjusts a feedback control system that controls the tilt angle around the X axis, and 440 is a PID compensator 439.
In addition, a filter for adjusting a feedback control system for controlling the tilt angle around the X axis, 441 is a tilt angle command around the Y axis of the Y stage, and 442 is a tilt angle around the Y axis and a tilt angle command 441 that are fed back. Is a PID compensator for adjusting the feedback control system that controls the tilt angle around the Y axis, and 444 is P
A filter 445 that adjusts a feedback control system that controls the tilt angle around the Y axis together with the ID compensator 443 includes a Z direction position feedback control system for the Y stage, a tilt angle feedback control system around the X axis, and a tilt angle feedback control system around the Y axis. A thrust distributor, 446a, 446b, 44, which calculates thrust commands to the electromagnets that apply thrust in the Z direction of the Y stage from three feedback control systems including the tilt angle feedback control system.
6c and 446d are current amplifiers 447a and 44 for amplifying the thrust command output from the thrust distributor 445 and driving the electromagnet.
7b, 447c, 447d are electromagnets 448a, 448b, 448c, which generate thrust in the Z direction of the Y stage,
448d is a displacement detector fixed to the Y stage, 449d
Is a displacement detector 448a, 448b, 448c, 448d
Based on the displacement detected at
An axis converter that calculates the tilt angle about the axis and the tilt angle about the Y axis, 450 is a Z-direction position feedback signal of the Y stage calculated by the axis converter 449, and 451 is the axis converter 4.
The tilt angle feedback signal about the X-axis of the Y stage calculated at 49, 452 is the Y calculated at the axis converter 449.
It is a tilt angle feedback signal of the stage about the Y-axis.

By controlling the XY stage shown in FIG. 2 with the controller shown in FIG. 4, the members 207 and 208a,
The X stage constituted by 208b controls the X direction position in the coordinates of FIG. 2 and the tilt angle about the Z axis. The Y stage 213 is controlled in a Y direction position which is a moving direction and a tilt angle around the Z axis, and in addition, a Z direction position, a tilt angle around the X axis, and a tilt angle around the Y axis.

As described above, by controlling each tilt angle of the stage in addition to the position in the moving direction of each stage, the position is always maintained against the external force applied to the stage, and the rigidity of the stage is improved. The tilt angle controlled by the Y stage is larger than that of the X stage because the object to be positioned is mounted on the Y stage in the XY stage in FIG. 2, the Y stage is lighter in weight, and -Because both Y stages use the base plate 201 for guiding in the Z direction, the rigidity of the Y stage in the Z direction can be improved by improving the rigidity of the Y stage in the Z direction. is there.

At this time, the displacement detectors 212a, 212
When the displacement of the Y stage in the Z direction is detected by observing the upper surface of the base surface plate 201 with b, 212c and 212d, the displacement detector detects a scratch or dust 507 attached on the guide 101 as shown in FIG. By doing so, the detected displacement signal becomes Zsens and an error Zerr occurs even though the bearing gap is at the control target Zref. This error Ze
A thrust force is generated in the bearing clearance direction to correct rr and Y
The posture of the stage is changed by mistake. In addition, an extra thrust must be generated to correct the displacement change due to scratches and dust. In the XY stage configured as shown in FIG. 2, the guide surface of the base surface plate 201 has a large exposed area, and the possibility of scratches and dust adhering to the XY stage is extremely high. Therefore, in the method of directly detecting the surface of the base surface plate, it is necessary to pay close attention to how to handle the XY stage and its installation environment.

On the other hand, in the present embodiment, the base plate surface is not directly detected, but the target member 4 shown in FIG.
14a, 414b, 414c, 414d are provided, and the target members 414a, 414b, 414c, 414d are provided.
The displacement in the Z direction is detected.

Target members 414a, 414b, 41
Since 4c and 414d (corresponding to the target member 107 in FIG. 1) are provided with the fluid bearing 108 as shown in FIG. 1, even if the target member comes on scratches or dust adhering to the base surface plate, the fluid film It is less affected by the averaging effect of. Especially, when compressed air is used as the fluid, the effect becomes remarkable.

Target members 414a, 414b, 41
4c and 414d move in the XY direction on the base surface plate 201 of FIG. 2 along with the movement of the XY stage, and the Z direction moves following the surface of the base surface plate, so the Z direction of the target member. The displacement of the Y stage in the Z direction (bearing gap displacement) can be stably measured by detecting the displacement of the Y stage. Also,
By designing the resonance frequency determined by the spring constant of the target member and the fluid film formed on the bottom thereof to be sufficiently higher than the resonance frequency of the Y stage, there is no adverse effect on the control characteristics by the feedback control system of FIG. be able to.

The target member is constrained from the stage 213 in the moving direction (XY direction in FIG. 2) and is supported so as to be freely movable in the guide surface direction (Z direction in FIG. 2) orthogonal to the moving direction. 1
The same effect can be obtained by supporting by the leaf spring 610 as shown in FIG. 6 instead of supporting by the fluid bearing 110 of FIG.

Further, since the means for applying thrust in the Z direction as the positioning device may be applied with thrust without contact with the guide like an electromagnet, the piezoelectric element 71 as shown in FIG.
It may be an active bearing device composed of 1 and the fluid bearing 704. What is an active bearing device? Fluid bearing 7
04 is a device for forcibly displacing 04 with a piezoelectric element 711 or the like to change the force generated in the fluid film.

As described above, according to the present embodiment, the target member provided with the fluid bearing as the guide that moves together with the moving stage and moves along the guide surface and in the bearing gap direction of the moving stage. A means for generating a thrust, a means for detecting the displacement of the target member in the bearing gap direction from the moving stage, and a control device for adjusting the thrust based on the displacement signal detected by the displacement detection means,
By adjusting the thrust in the bearing gap direction and controlling the bearing gap by the control device, a small and highly rigid moving stage can be obtained.

Further, since the fluid bearing of the target member makes it less susceptible to scratches and dust attached to the guide surface, the use environment is restricted and handling is facilitated, and a movable stage having good usability can be obtained.

[0041]

As described above, according to the present invention, it is possible to provide a positioning device capable of increasing the bearing rigidity without increasing the size of the device.

[Brief description of drawings]

FIG. 1 is a diagram showing a moving stage structure in a positioning device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration of an XY stage according to an embodiment of the present invention.

FIG. 3 is a perspective view showing a configuration of an XY stage according to an embodiment of the present invention.

FIG. 4 is a block diagram showing a control device for positioning control of an XY stage.

FIG. 5 is a diagram for explaining a problem in the conventional method.

FIG. 6 is a diagram showing a modification of the positioning device of the present invention.

FIG. 7 is a diagram showing a modification of the positioning device of the present invention.

[Explanation of symbols]

101 Guide 102 Moving Stage 103 Fluid Bearing 104 Electromagnet 105 Displacement Detector Holder 106 Displacement Detector 107 Target Member 108 Fluid Bearing 109 Preload Magnet, 110 Fluid Bearing 201 Base Surface Plate, 202a, 202b X Stage Guide 203a, 203b X Stage Linear motor stators 204a, 204b X stage linear motor movers 205a, 205b X stage measurement mirror (205
b is not shown) 206a, 206b X stage connecting plate 207 Part of X stage that also serves as a guide for Y stage 208a, 208b Part of X stage (208a is not shown) 209a, 209b For Y stage Linear motor stators 210a, 210b Y stage linear motor movers 211a, 211b Y stage measurement mirror (211)
b is not shown) 212a, 212b, 212c, 212d Displacement detector 213 Y2 stage 214a, 214b, 214c, 214d Target member of the displacement detector (214b, 214c are not shown) 401 X stage movement direction position Command 402 Subtractor 403 PID compensator 404 Filter 405 X stage tilt angle around Z axis Command 406 Subtractor 407 PID compensator 408 Filter 409 Thrust distributor 410a, 410b Current amplifier 411a, 411b Linear motor 412 X stage 413a, 413b Laser length measuring device 414 Axis converter 415 X stage moving direction position feedback signal 416 X stage tilt angle feedback signal 419 about Y stage moving direction position command 418 Subtractor 419 PID compensator 4 20 Filter 421 Y stage inclination angle command 422 Subtractor 423 PID compensator 424 Filter 425 Thrust distributor 426a, 26b Current amplifier 427a, 27b Linear motor 428 Y stage 429a, 29b Laser length measuring machine 430 Axis converter 431 Y stage movement direction position feedback signal 432 Y stage tilt angle feedback signal about Z axis 433 Y stage Z direction position command 434 Subtractor 435 PID compensator 436 Filter 437 Y stage tilt angle command 438 Subtractor 439 PID compensator 440 Filter 441 Y stage tilt angle command 442 Subtractor 443 PID compensator 444 Filter 445 Thrust distributor 446a, 446b, 446c, 446d Current amplifier 447a, 447b, 44 c, 447d Electromagnets 448a, 448b, 448c, 448d Displacement detector 449 Axis converter 450 Y stage moving direction position feedback signal 451 Y stage X axis tilt angle feedback signal 452 Y stage Y axis tilt angle feedback signal 506 Displacement detector holder 507 Scratches or dust attached to the guide 610 Leaf spring 704 Fluid bearing 711 in the active bearing device Piezoelectric element in the active bearing device

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Claims (6)

[Claims] 1. A positioning device for positioning a moving stage supported by a fluid bearing with respect to a base, wherein the moving stage is moved in a direction perpendicular to a pressure surface of the fluid bearing for receiving fluid pressure. Driving means for applying a force so that it moves integrally with the moving stage in the moving direction of the moving stage, and is supported so as to be movable relative to the moving stage in a direction perpendicular to the pressure surface. A target member, a support means for supporting the target member with respect to the base through a fluid in a direction perpendicular to the pressure surface, and a relative position in a direction perpendicular to the pressure surface of the moving stage and the target member. A detecting means for detecting a position, and adjusting the generated force of the driving means based on the detection result of the detecting means, Positioning device and controls the bearing clearance. 2. The target member is supported by the base through a fluid and is attracted to the base by a magnet, and the target member is balanced by the pressure of the fluid and the attraction force of the magnet. The positioning device according to claim 1, wherein the positioning device holds a predetermined distance from the base. 3. The positioning device according to claim 1, wherein the target member is supported on the moving stage by a fluid bearing. 4. The positioning device according to claim 1, wherein the target member is supported on the moving stage by a leaf spring. 5. The positioning device according to claim 1, wherein the driving unit includes an electromagnet. 6. The positioning device according to claim 1, wherein the drive means includes a fluid bearing and a piezoelectric element that moves the fluid bearing in a direction perpendicular to a pressure surface thereof.