JPH08285176A - Hybrid type vibration damping and eliminating device - Google Patents

Abstract

PURPOSE: To improve vibration eliminating and vibration damping performance of the whole device by mainly making an active vibration resistant device using an air spring as an actuator take charge of postural control of a very heavy cargo and an active vibration resistant device using a VCM as an actuator take charge of vibration damping control. CONSTITUTION: In a vibration clamping and eliminating device where an active vibration resistant device using an air spring 1 as an actuator takes charge of postural control of a very heavy cargo and an active vibration resistant device using a voice coil motor 11 as an actuator takes charge of vibration damping control, the device is provided with four air springs and four voice coil motors as actuators arranged in the four corners of a plate-like surface plate for vibration damping and vibration resistance in a horizontal plane. Air springs having a driving shaft in the same direction are arranged in two places of diagonal positions of the plate-like surface plate, and air springs having a driving shaft in the direction orthogonal to the driving direction are arranged in two places of a pair of another diagonal positions, and the voice coil motors having a driving shaft orthogonal to the driving direction of a driving shaft of the respective four air springs, are provided in the vicinity of the respective air springs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid vibration damping / vibrating apparatus using an air spring and a voice coil motor as an actuator, and is particularly suitable as a unit of a semiconductor manufacturing apparatus having an XY stage for exposure mounted thereon. Concerning what is used for.

[0002]

2. Description of the Related Art Conventionally, a device group that is sensitive to vibration is mounted on a vibration isolation table. For example, it is an optical microscope or an XY stage for exposure. In particular, in the case of the XY stage for exposure, the stage must be mounted on a vibration isolation table in which vibration transmitted from the outside is eliminated as much as possible so that proper and quick exposure can be performed. This is because the exposure must be performed with the exposure XY stage completely stopped. Further, it should be noted that the exposure XY stage has an intermittent operation called step & repeat as an operation mode, and the step vibration itself is repeatedly generated, which causes shaking of the vibration isolation table. Even if this kind of vibration remains unsettled, it is impossible to start the exposure operation. Therefore, the anti-vibration table is required to achieve a good balance between the anti-vibration against external vibration and the damping performance of the forced vibration caused by the movement of the mounted device itself.

Instead of a step-and-repeat type semiconductor manufacturing apparatus in which an XY stage is completely stopped and then a silicon wafer mounted on the stage is irradiated with exposure light, exposure is performed while scanning the XY stage and the like. A scanning type semiconductor exposure apparatus for irradiating a silicon wafer with light has also appeared. Even for the vibration isolation table used in such a device, it is possible to satisfy a well-balanced balance between the vibration isolation against external vibration and the vibration isolation performance against the forced vibration caused by the movement of the equipment itself mounted on the vibration isolation table. The requirements are the same.

As is well known, the vibration isolation table is classified into a passive vibration isolation table and an active vibration isolation table. In recent years, there has been a tendency to use an active vibration isolator in order to meet the demands for high-precision positioning, high-precision scanning, high-speed movement, etc., which are required for equipment mounted on a vibration isolation table. Actuators used in active vibration isolation devices include air springs, voice coil motors, piezoelectric elements, and the like.

First, referring to FIG. 3, an air spring type supporting leg 1 in an active vibration isolator using an air spring as an actuator.
The configuration and operation of the feedback device 19 for 2 will be described. In the figure, 13 is a servo valve for supplying / exhausting air as a working fluid to / from the air spring 14, 15 is a position sensor for measuring the vertical displacement of the support base 16, 17 is a mechanical spring for preload, and 18 is an air spring 14. Preload mechanical spring 1
7 and a viscous element that expresses the viscosity of the entire mechanism (not shown). The mechanism assembled from these components is called the air spring support leg 12. Next, the configuration and operation of the feedback device 19 for the air spring type support leg 12 will be described. First, the output of the acceleration sensor 20 is negatively fed back to the preceding stage of the voltage / current converter 22 for opening / closing the valve of the servo valve 13 via a low pass filter or a band pass filter 21 having an appropriate amplification degree and time constant.
The mechanism is stabilized by this acceleration feedback loop. That is, damping is added. Further, the output of the position sensor 15 is the displacement amplifier 23.
It becomes an input of the comparison circuit 24 through. here,
A deviation signal e is obtained by comparing with a target voltage 25 equivalent to a target position with respect to the ground on which the air spring type support leg 12 is in contact. The deviation signal e passes through the P1 compensator 26 to excite the voltage-current converter 22. Then, the pressure inside the air spring 14 is adjusted by opening / closing the servo valve 13, and the support base 16 can be held at a desired position designated by the target voltage 25 without a steady deviation. Here, P means proportional and I means integral operation. The air spring type support leg 12 using the air spring 14 as an actuator has the ability to mount a heavy object on the support base 16. However, a high-speed response could not be expected for the closed loop system including the air spring type support legs 12 and the feedback device 19.

Next, the structure and operation of the feedback device for the supporting leg in the active vibration isolator that uses a voice coil motor (hereinafter referred to as VCM) consisting of a permanent magnet and a winding coil as an actuator will be described. The basic configuration of the control loop is to convert the output signal of the acceleration sensor into a velocity signal through an integrator, excite the power amplifier that drives the VCM with this signal, and consequently give damping to the supporting surface plate. FIG. 4 shows a basic configuration of a control loop in a vibration isolation device using a VCM. In the figure, 29 is an appropriate prefilter for receiving the output signal of the acceleration sensor and removing offset and high frequency noise, and 30 is an integrator for converting the output signal of the prefilter 29 into a velocity dimension. , 31 are power converters for driving a VCM (not shown). The integrator 30 may be a pseudo integrator if necessary. The active vibration isolation device using the VCM as an actuator is characterized by quick response.
However, in order to support the positioning of a heavy object, a constant current must be passed through the winding coil, which causes a problem of heat generation and is disadvantageous. Normally, the control loop is configured to drive the VCM in response to only the generated vibration.

An active vibration isolator using an air spring as an actuator has an excellent ability to control a position of a posture by supporting a large heavy object including a surface plate. However, since the response of the control loop is slow, in order to cancel the influence of the vibration generated by the mounted device, the drive signal of the device is compensated and the actuator of the air spring is driven in a feedforward manner to suppress the influence of the vibration. It was inferior in terms of ability. On the other hand, the active vibration isolation device using the VCM as an actuator has agile response, but has no ability or is inferior to the ability to perform positioning control of the posture of the entire device.

Therefore, the active vibration isolation device using the air spring as the actuator is mainly responsible for the attitude control of the heavy object, and the active vibration isolation device having the VCM as the actuator is mainly responsible for the vibration suppression control. It was also considered to improve the vibration damping performance.

As a known example of an active vibration isolator using both an air spring and a VCM as an actuator, Japanese Patent Application Laid-Open No. 6-117
No. 480, etc. Here, a vibration eliminating device using both an air spring and a VCM is used, in which a large heavy object on the surface plate is supported by an air pressure spring, a load acting on the surface plate is detected from a change in air pressure, and the detection signal is detected. A configuration is shown in which the VCM is driven through a compensator that calculates a control constant using an appropriate algorithm. In addition, a configuration in which an air spring and a VCM are skillfully arranged in the same support leg is shown. What has is disclosed. However, there is no disclosure regarding the arrangement of the actuators in the support leg in the horizontal direction, which is the configuration in which the posture is controlled in the gravity direction.

Further, as a publicly known example in which two types of vibration isolation devices are combined, there is JP-A-6-42578.
It was devised for the purpose of achieving both vibration isolation effect for floor vibration and control effect for movement reaction force in the equipment.In parallel with the passive vibration isolation device, a passive damper member or a passive spring member, Disclosed is a semi-active damper device or a semi-active rigid mechanical device including an electromagnet and a controller that controls the electromagnet. There is an advantage that a heavy object including a surface plate can be supported inexpensively and easily by the passive vibration isolator. However, it has not been possible to meet the demand for delicately positioning the posture of the supporting object. what if,
Even if the passive anti-vibration device can be positioned in a desired posture by mechanical adjustment, the posture will change due to the characteristic change over time of the passive components that make up the passive anti-vibration device. was there. Finally, the following documents are cited as known examples showing the arrangement of the air springs in the horizontal direction.

Yasuda, Osaka, and Ikeda: “Study of Active Vibration Isolator with Combined Feedforward Control,” Proc. vol. 58. No. 552. p. 238
1, (1992-8) The above document describes the configuration in which eight air springs are arranged at the four corners of a flat plate. Four air spring actuators are arranged for vertical support and the remaining four air springs are arranged for horizontal support. Here, 2 for each of the x and y axis directions in the horizontal direction.
Individual air springs are used and are arranged diagonally on a flat plate. The so-called horizontal air springs are arranged in a windmill. It is intended to eliminate redundant air spring arrangements in the horizontal direction and to achieve horizontal vibration suppression and vibration isolation by using the minimum required air springs, which provides an excellent device configuration for industrial devices. there were.

Here, FIG. 5 shows the structure of the air spring type supporting leg for supporting the active vibration isolation device using the air spring as the actuator in the horizontal plane. In the figure, 1
Is an air spring, 2 is a support leg frame mechanically connected to the main body device supported by the air spring 1, 3a and 3b are mechanical springs for preload, and 4 is a support for mechanically contacting the driving force of the air spring 1 with the main body device. This is a force pin for transmission to the leg frame 2, and these constituent elements constitute an air spring type supporting leg 5 which supports in the horizontal plane. In addition, the shaded portion in the figure indicates a portion mechanically in contact with the installation floor.
Subsequently, the air spring type support legs 5a, 5 having the same structure as in FIG.
FIG. 6 shows a top view when b, 5c, and 5d are arranged at the four corners of the plate-shaped surface plate 6. Using the xyz coordinate system in the figure, the air spring type support legs 5a generate driving force in the x-axis direction, 5b generate the y-axis direction, 5c generate the x-axis direction, and 5d generate the driving force in the y-axis direction. Each air spring is arranged so that That is, the air spring is arranged in the wind turbine.

Next, FIG. 9 shows the structure of a flat plate type linear motor 11 which is an example of a VCM. In the figure, 7 is a permanent magnet, 8 is a winding coil, 9 is a support frame for the winding coil 8,
Reference numeral 10 is a fixed frame for fixing the permanent magnet 7. When the support frame 9 is firmly fixed and current is applied to the winding coil 8, the fixed frame 10 including the permanent magnet 7 is wound when the fixed frame 10 is firmly fixed and current is applied to the winding coil 8. The support frame 9 including the wire coil 8 obtains a driving force.

In order to realize a hybrid type vibration damping / vibrating device using both an air spring and a VCM, how to install the air spring 1 and a flat plate type linear motor 11 which is an example of the VCM into a support leg becomes a problem. When the air spring is used for positioning a heavy object and the VCM is used for damping, it is considered that these actuators are housed in the same support leg. Generally, support legs are arranged in parallel so that the driving directions of both the air spring and the VCM are the same. FIG. 7 shows an example of this. The flat type linear motor 11 shown in FIG. 9 is incorporated in the air spring type supporting leg 5 shown in FIG. 5, and the driving directions of both are the same. However, the air spring 1 and the preload mechanical spring 3a. Since the flat plate type linear motor 11 must be newly incorporated in the mechanism composed of 3b and the like, there is a problem that the support leg becomes large. Further, due to the mismatch between the driving point of the air spring 1 and that of the flat plate type linear motor 11, the mechanical parts for fixing the two actuators are bent, which is undesirable vibration for the vibration isolator. There was a problem of causing.

[0015]

An active vibration isolator using an air spring as an actuator has an excellent ability to control the position of a posture by supporting a large heavy object including a surface plate. However, since the response of the control loop is slow, it is inferior in terms of the ability to compensate for and suppress the vibration generated by the on-board equipment, for example, in a feedforward manner. on the other hand,
An active vibration isolation device using a VCM as an actuator has agile response. Therefore, if the vibration generated by the on-board equipment is detected and fed back, or if it is compensated in a feedforward manner, it has the ability to suppress it instantaneously.
However, the ability to position and control the posture of the entire device is inferior or has no ability at all. Therefore, by constructing an active vibration isolation device having both an air spring and a VCM as actuators,
It has already been devised to satisfy both performances of attitude control and vibration control. However, especially in the horizontal control of the active vibration isolator supporting the flat platen, there is a performance problem caused by the fact that both actuators are not arranged properly, and there is a problem to solve it. It had been.

[0016]

In the present invention, the active vibration isolation device using an air spring as an actuator is mainly in charge of attitude control, and the active vibration isolation device using a VCM as an actuator is mainly in charge of damping control. Therefore, the purpose is to improve the vibration isolation and damping performance of the entire apparatus, and for that purpose, a suitable arrangement of the air spring and the VCM is provided especially in the horizontal plane.
More specifically, for the purpose of vibration damping in the horizontal plane, four air springs and four VCMs are provided as actuators for arranging at the four corners of the flat plate, and the diagonal of the flat plate is provided. An air spring having the same drive shaft is arranged at two positions, and an air spring having a drive shaft orthogonal to the driving direction is arranged at another pair of diagonal positions at two positions to drive four air springs. A VCM having a drive axis orthogonal to the drive direction of the axis is provided in the vicinity of each air spring to constitute a hybrid vibration damping and vibration isolator.

[0017]

By the actuators of the air springs arranged in the four corners of the flat platen surface plate, the movement of the identification plate in the horizontal plane in three degrees of freedom, namely, the x-axis translational motion, the y-axis translational motion and the rotation around the z-axis. Positioning control of movement.

At the same time, by arranging VCMs having drive shafts orthogonal to the drive shafts of the air springs arranged at each of the four corners in the vicinity of the air springs, vibration of three degrees of freedom acting on the surface plate,
That is, translational vibration in the x-axis direction, translational vibration in the y-axis direction, and rotational vibration about the z-axis are suppressed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the structure of a hybrid vibration damping and vibration isolator according to an embodiment of the present invention. In the figure, hybrid support legs 28a, 28b, 28 for horizontal support are shown.
c and 28d are arranged at the four corners of the plate-shaped surface plate 6.
FIG. 8 shows a structure of these hybrid support legs 28. In FIG. 8, the support frame 9 for supporting the winding coil 8 is joined to a hatched member so that the flat plate type VCM 11 has a degree of freedom of driving in a direction orthogonal to the driving direction of the air spring 1. ing. That is, the fixed frame 10 including the permanent magnet 7 is movable. Referring again to FIG. 1, the hybrid support legs 28a, 28b, 28
The driving directions of the air springs of c and 28d are x direction and y direction, respectively.
Direction, x direction, y direction, and the drive directions of the flat plate type VCMs of these support legs are the y direction, x direction, y direction, and x direction. In order to construct FIG. 1, an air spring and a VCM having a drive shaft orthogonal to the air spring were housed in the same support leg as shown in FIG. 8, for example. However, they do not necessarily have to be incorporated in the same support leg. The point is that these two types of actuators whose drive axes in the horizontal plane are orthogonal to each other may be arranged close to each other at the four corners of the flat plate.

After all, the contents of the present invention shown in FIG. 1 can be simply expressed as shown in FIG. In the figure, A is an air spring and V is
Represents a flat plate type VCM, and the arrows from A and V indicate the acting directions of the driving force in the illustrated xyz coordinate system. Both of the four air springs indicated by A and the four flat plate type VCMs indicated by V are arranged in a windmill, but when one supporting leg is seen, the driving directions of the air springs and the flat plate type VCM are shown. Are orthogonal to each other. Therefore, the wind turbine arrangement made by the air spring has a structure in which the wind turbine arrangement made up of the flat plate type VCM is inserted in the empty portion of the arrangement.

[0021]

By arranging the air springs as the actuators at the four corners of the flat plate-like surface plate in a windmill shape, there is an advantage that the use of redundant actuators can be suppressed and an economical device configuration can be realized. However, in general, the surface plate 6 cannot be made to have a symmetrical structure, and when a device for driving operation is mounted on the surface plate 2 as described above, the rotation posture (around the z-axis) is inevitably constrained. The ability is inferior, and therefore the ability to withstand the moment disturbance around the z-axis is not sufficient. There was a problem.

However, according to the hybrid vibration damping / vibrating device of the present invention shown in FIG. 1, there are air springs arranged at the four corners of the surface plate, and the flat plate type VCM for vibration damping has no air springs. The windmill is placed in the location. Therefore, there is an effect that the positioning performance by the action of the air spring and the vibration damping performance by the action of the flat plate type VCM can be satisfied in a well-balanced manner.

In the conventional case where the air spring and the flat plate type VCM are arranged in parallel so that the driving directions are the same,
The mechanical components are deformed due to the mismatch of the driving points, or local mechanical vibrations are caused, which deteriorates the vibration isolation and vibration damping performance of the vibration isolation device. The vibration damping and vibration isolator also has an effect of avoiding such a problem.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a hybrid vibration damping / vibrating device according to an embodiment of the present invention.

FIG. 2 is a block diagram simply expressing the content of the invention.

FIG. 3 is a configuration of a feedback device for a support leg that uses an air spring as an actuator.

FIG. 4 is a basic configuration of a control loop in a vibration isolation device using a VCM.

FIG. 5 is a diagram showing a structure of an air spring type support leg.

FIG. 6 is a layout view of support legs.

FIG. 7 is a diagram showing a first structure of a hybrid support leg.

FIG. 8 is a diagram showing a second structure of the hybrid support leg.

FIG. 9 is a structural diagram of a flat plate type linear motor.

[Explanation of symbols]

1: Air spring, 2: Support leg frame, 3a, 3b: Preload mechanical spring, 4: Force pin, 5, 5a, 5b, 5
c, 5d: Air spring type supporting legs, 6: Surface plate, 7: Permanent magnet, 8: Winding coil, 9: Support frame, 10: Fixed frame, 1
1: Flat plate type VCM, 12: Air spring type support leg, 13: Servo valve, 14: Air spring, 15: Position sensor, 1
6: support base, 17: mechanical spring for preload, 18: viscous element,
19: feedback device, 20: acceleration sensor, 2
1: Low-pass filter or band-pass filter, 2
2: Voltage-current converter, 23: Displacement amplifier, 24: Comparison circuit, 24, 25: Target voltage, 26: PI compensator, 27:
Hybrid support legs, 28: Hybrid support legs, 2
9: prefilter, 30: integrator, 31: power amplifier.

Claims (2)

[Claims] 1. A vibration damping device for causing an active vibration damping device having an air spring as an actuator to carry out posture control of a heavy object, and an active vibration damping device having a voice coil motor as an actuator for damping control. For the purpose of vibration damping in the horizontal plane, four air springs and four voice coil motors are provided as actuators to be placed at the four corners of the flat plate, and the flat plate has two diagonal positions. An air spring having a drive shaft in the same direction is arranged, and an air spring having a drive shaft in a direction orthogonal to the drive direction is arranged at another pair of two diagonal positions, and the drive shaft of each of the four air springs is arranged. A hybrid type vibration damping / isolating device, characterized in that a voice coil motor having a drive shaft orthogonal to the drive direction of is provided near each air spring. 2. The hybrid type vibration damping / vibrating device according to claim 1, wherein the voice coil motor is a flat plate type voice coil motor.