JPH09236149A - Method of controlling anti-vibration device and anti-vibration device using the method - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To obtain an accurate mechanical constant of an object to be vibration-isolated, and to accurately control the vibration-damping device based on the mechanical constant. SOLUTION: Prior to actual operation, a reticle 28 and a reticle stage 2 are driven by driving an actuator 7A of a vibration control device and other actuators by a second controller 12.
7, the main state of the projection exposure apparatus such as the wafer 22 and the wafer stage 20, the first column 24 and the second column 26 that support them, and the vibration state of the exposure apparatus main body 30 that includes the surface plate 6 that supports them. Measurement is performed by the acceleration sensors 32A to 32D and the displacement sensors 33A to 33C, and the mechanical constant of the exposure apparatus main body 30 is calculated by the calculation unit 13. The calculation unit 13 obtains a parameter for determining the drive amount of each actuator from the mechanical constant, and the first control unit 11 controls the operation of each actuator during actual operation based on this parameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling an anti-vibration device for suppressing vibration of a target device and an anti-vibration device using the control method, and more particularly to photolithography for manufacturing semiconductor elements and the like. It is suitable to be applied to an active vibration isolation device of an exposure apparatus used in a process.

[0002]

2. Description of the Related Art Conventionally, in a photolithography process for manufacturing a semiconductor device, a liquid crystal display device, an image pickup device (CCD or the like), a thin film magnetic head or the like, a pattern on a reticle (or a photomask or the like) is formed on a wafer (or a photomask). Or, a projection exposure apparatus such as a stepper or an exposure apparatus such as a proximity type exposure apparatus is used for exposing on a glass plate or the like). In these exposure apparatuses, for example, an extremely high vibration isolation characteristic is required in order to transfer a reticle pattern onto a wafer with high overlay accuracy. Therefore, the main body of these exposure apparatuses (the portion that transfers the pattern of the reticle onto the wafer) is installed on a vibration isolator for damping external vibrations and internal vibrations.

This anti-vibration device is usually composed of a combination of a spring material and a vibration-damping material. Conventionally, the anti-vibration performance does not change depending on the vibration condition or the condition (posture etc.) of the device, that is, it is passive. The anti-vibration device, which can be called a typical anti-vibration system, has been used. These vibration isolators are generally called "passive vibration isolators". On the other hand, an "active type anti-vibration device" that detects the external or internal vibration state in real time by a sensor such as an accelerometer or a displacement gauge and actively changes the performance of the anti-vibration device is also used recently. It has become.

By the way, the vibration isolator used in the exposure apparatus is mainly required to have two functions. One is the function of not transmitting the vibration from the floor where the exposure equipment is installed to the exposure equipment main body, and the other is the vibration inside the exposure equipment main body generated by driving the stage part inside the exposure equipment. It is a function of promptly dampening. These two functions are originally contradictory functions in the case of the passive type vibration damping device that has been used for a long time, and there is a relationship that if either function is strengthened, the other function is impaired.
On the other hand, if it is an active type anti-vibration device, those 2
Recently, the active vibration damping device has been attracting attention because it can satisfy two functions.

The active type vibration damping device generally uses an air spring (air damper), which is a soft spring having a small rigidity, as a mount for supporting the weight of the entire vibration damping target device. High frequency components (20Hz
In addition to the effect of blocking the vibration transmission described above, the vibration component in the low frequency region is characterized by being suppressed by the feedback control of the vibration detection sensor and the actuator that generates the thrust for vibration suppression.

When applied to an exposure apparatus, such an active anti-vibration apparatus has a mount portion for supporting the weight of the exposure apparatus body, a position sensor for detecting the posture and position of the exposure apparatus body, A vibration sensor (velocity or acceleration sensor) for detecting the motion state (vibration) of the exposure apparatus main body, an actuator for generating a vibration suppression force for the exposure apparatus main body, and an actuator-generated thrust based on the measurement value of the sensor. The control unit for calculation and the like are configured as main elements. Then, the exposure apparatus main body is stably supported, and the vibration of the exposure apparatus main body is controlled in all degrees of freedom (6
In order to measure and control (degree of freedom), at least three or more mount parts, six or more position sensors or vibration sensors, and six or more actuators are required.

In recent years, exposure apparatuses are required to have higher and higher positioning accuracy. Further, since the exposure apparatus is complicated, the residual vibration amount allowed in the active type vibration isolation apparatus becomes more and more severe, and is shifting from the micron order to the submicron order. In order to perform such control, the weight, center of gravity, moment of inertia, inertial spindle, etc. as mechanical constants are accurately determined in the above control unit, and the actuator operation is calculated based on these mechanical constants. Need to control.

[0008]

However, in the case of an exposure apparatus such as a stepper, it has been considered that it is extremely difficult to set mechanical constants with sufficient accuracy in advance by a simple method. There was no suitable method other than using mechanical constants calculated by design drawings. The value of the mechanical constant based on such calculation is used while being corrected based on the actual measurement value for each subelement, but it cannot be denied that it is lacking in accuracy. Therefore, when such a calculated value is used as a mechanical constant in the control unit, there is a disadvantage that the vibration of the device cannot be controlled with high accuracy.

In view of the above point, the present invention provides a method for controlling an anti-vibration device capable of obtaining an accurate mechanical constant of an anti-vibration object and controlling the anti-vibration device with high accuracy based on this mechanical constant. The purpose is to do. Another object of the present invention is to provide a vibration isolation device capable of implementing such a control method.

[0010]

A method for controlling an anti-vibration device according to the present invention comprises a plurality of anti-vibration mounts (3A to 3D) for supporting an anti-vibration object (30) on an installation surface (2), and a plurality thereof. Detection sensors (32A to 32D, 33A to 33C) that detect the posture and motion state of the vibration isolation target (30), and an actuator that controls the vibration of the vibration isolation target (30) based on the output of this detection sensor. (7A-7D, 31A-31
C) and a method for controlling an anti-vibration device, the actuator is driven by a predetermined amount to vibrate the anti-vibration object (30) to capture the response output of the detection sensor, and Based on the relationship with the response output of the detection sensor, the image stabilization target (3
0) mechanical constants (weight, moment of inertia, etc.) are obtained. According to such a control method of the vibration isolator of the present invention, based on the response output of those detection sensors with respect to the drive amount of the actuator provided in the vibration isolator,
The mechanical constant of the vibration isolation target (30) is obtained. Therefore, the mechanical constant can be accurately determined without using a measuring device for specifically determining the mechanical constant. Then, the vibration isolator can be controlled with high accuracy based on the mechanical constant.

In this case, a parameter (gain or the like) for determining the drive amount (thrust or the like) of the actuator from the output of the detection sensor based on the obtained mechanical constant.
Is determined, and the operation of the actuator is controlled by using the determined parameter. As a result, the parameter for obtaining the drive amount of the actuator is accurately obtained, and the operation of the actuator can be controlled with high accuracy based on the accurate parameter.

Further, the calculation of the mechanical constants of the anti-vibration object (30) and the determination of the parameters thereof may be performed at the initialization of the control of the anti-vibration device. This allows
Optimal vibration isolation can be performed even if the state of the vibration isolation target changes. Further, the vibration isolation device according to the present invention includes a plurality of vibration isolation mounts (3A to 3D) that support the vibration isolation target (30) on the installation surface (2), and the postures of the vibration isolation target (30). Detection sensor (32A to 32) for detecting a motion state
D, 33A to 33C) and an actuator (7A to 7D, 31A to 31C) for controlling the vibration of the vibration isolation target (30) based on the output of the detection sensor, the detection thereof. First control means (11) for controlling the drive amount of the actuator based on the output of the sensor and a predetermined parameter, and second control means (11) for controlling the drive amount of the actuator irrespective of the output of the detection sensor ( 12) and based on the response output of the detection sensor when the actuator is driven by a predetermined amount via the second control means, the mechanical constant of the vibration isolation target (30) is obtained, and from this mechanical constant An arithmetic means (13) for determining the value of the predetermined parameter for determining the drive amount of the actuator from the output of the detection sensor. According to such a vibration isolation device of the present invention, it is possible to implement the above-described control method of the vibration isolation device of the present invention,
Highly accurate vibration isolation performance can be obtained based on accurate mechanical constants.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described below with reference to the drawings. In this example, the present invention is applied to a vibration isolation device of a stepper type projection exposure apparatus. FIG. 1 is a perspective view showing the overall configuration of the projection exposure apparatus of this example. In FIG. 1, four vibration isolation mounts are mounted on a base frame 2 fixed on the floor in a predetermined chamber. 3A to 3D (see FIG. 2, 3A to 3C in FIG. 1)
Only appears. The same shall apply hereinafter) is installed, and the surface plate 6 of the projection exposure apparatus is installed via these four vibration isolation mounts 3A to 3D. The anti-vibration mounts 3A to 3D each include a vertical movement mechanism (not shown) fixed on the base frame 2, a vibration absorbing system on the vertical movement mechanism, and a load sensor in contact with the surface plate 6. Here, as will be described later, since the projection optical system 25 is used in this example, the Z axis is taken parallel to the optical axis of the projection optical system 25, and the orthogonal coordinate system in the plane perpendicular to the Z axis is defined as X. The description will be given with respect to the axis and the Y axis.

FIG. 2 is a sectional view taken along the line AA of FIG. In this case, the line AA in FIG. 1 travels parallel to the upper part of the apparatus, and the + X of the first column 24 that supports the projection optical system 25 and the like.
The line is a line penetrating from the vicinity of the end in the direction to the lower part, advancing in the -X direction in the space on the wafer 22, and then penetrating the end in the -X direction of the first column 24 to reach the upper part of the device. As shown in FIG. 2, the vibration isolation mounts 3A to 3D are arranged near the four apexes of the quadrangular bottom surface of the surface plate 6, respectively.
These anti-vibration mounts 3A to 3D are controlled by the first control unit 11 that controls the operation of the entire apparatus. As will be described later, the vibration absorbing system in each of the vibration damping mounts 3A to 3D has a structure in which a vibration absorbing system using a spring member such as an air spring or a mechanical spring and a vibration absorbing system using a viscous fluid are integrated. Therefore, for convenience of description, the structure that constitutes the vibration absorbing system by the spring member will be described as a spring buffer system, and the structure that constitutes the vibration absorbing system by the viscous fluid will be described as a fluid buffer system.

Returning to FIG. 1, voice coil motor type actuators 7A and 7B are installed between the base frame 2 and the surface plate 6 in parallel with the vibration isolation mounts 3A and 3B. The actuators 7A and 7B are composed of stators 8A and 8B fixed to the base frame 2, and movers 9A and 9B fixed to the lower surface of the surface plate 6. The actuators 7A and 7B are usually provided with a first control unit 11 which controls the projection exposure apparatus via a switching unit 14, respectively.
Alternatively, as will be described later, when the mechanical constant of the exposure apparatus main body 30 is obtained, the second control unit 12 controls the first constant.
In response to an instruction from the control unit 11 or the second control unit 12, a biasing force from the base frame 2 to the bottom surface of the surface plate 6 in the Z direction or a suction force from the bottom surface of the surface plate 6 toward the base frame 2 is generated. In the other vibration-proof mounts 3C and 3D as well, similarly to the vibration-proof mounts 3A and 3B, the actuators 7C and 7D are installed in parallel (see FIG. 2), and the biasing force or the suction force of these actuators 7C and 7D is also the first, respectively. It is set by the control unit 11 or the second control unit 12. In this example, by the four actuators 3A to 3D, the displacement of the surface plate 6 in the Z direction, the rotation around the X axis, and the Y
Rotation about the axis is controlled. In this example, four actuators 7A are provided between the surface plate 6 and the base frame 2.
Although ~ 7D is installed, since there are three degrees of freedom to control, only three actuators may be provided.

A wafer stage 20 is fixed on the surface plate 6, and a wafer 22 is suction-held on the wafer stage 20 via a wafer holder 21. A four-legged first column 24 is provided on the surface plate 6 so as to surround the wafer stage 20.
The projection optical system 25 is fixed to the central portion of the upper plate of the first column 24. Further, a four-legged second column 26 is planted on the upper plate of the first column 24 so as to surround the projection optical system 25, and a reticle 28 is provided at the center of the upper plate of the second column 26 via a reticle stage 27. It has been placed. As shown in FIG. 2, the X-direction and the Y-direction of the wafer stage 20 are respectively provided at the −X-direction and −Y-direction end portions of the upper surface of the surface plate 6.
Laser interferometers 23X, 23 for measuring the directional position
Y is installed and these laser interferometers 23X, 2
Based on the measurement result of 3Y, the wafer stage 20 two-dimensionally positions the wafer 22, and
Has the functions of moving in the Z direction, rotating, and leveling.

Further, laser interferometers 29X and 29Y for measuring the positions of the reticle stage 27 in the X and Y directions are installed at the ends of the upper plate of the second column 26 in the -X and + Y directions, respectively. Reticle stage 2
Reference numeral 7 has a function of finely adjusting the two-dimensional position of the reticle 28 and adjusting the rotation angle based on the measurement values of the laser interferometers 29X and 29Y. An illumination optical system (not shown) is arranged above the reticle 28, and the projection optical system 2 for the pattern of the reticle 28 is provided under the illumination light for exposure from the illumination optical system.
The image through 5 is sequentially exposed on each shot area of the wafer 22. The above reticle stage 27 and wafer stage 20, and the first column 24 and the second column 24 that support them.
An exposure apparatus main body 30 is composed of the column 26, the surface plate 6, and the like.

As shown in FIG. 2, the first column 24 is planted on the surface plate 6 by four leg portions 24a to 24d. Further, in the vicinity of the corners of the upper plate of the first column 24 in the −X and −Y directions, the X direction, the Y direction, and the Z of the first column 24 are provided.
An acceleration sensor 32A for detecting the acceleration in the directional direction is installed, and an acceleration for detecting the acceleration in the Z direction of the first column 24 is provided in the vicinity of the + X, -Y direction corners of the upper plate of the first column 24. The sensor 32B is installed. Furthermore, the central end of the upper plate of the first column 24 in the + X direction, and + X,
Acceleration sensors 32C and 32D for detecting the acceleration in the Y direction and the acceleration in the Z direction of the first column 24 are installed at the corners in the + Y direction. Acceleration sensor 3
The detection results of 2A to 32D are supplied to the first controller 11. Further, the detection results of the acceleration sensors 32A to 32D are also supplied to the calculation unit 13 when obtaining the mechanical constants of the exposure apparatus main body 30. First column 24
Are planted on the surface plate 6, and the acceleration of the first column 24 is detected as the acceleration of the surface plate 6.

In addition to the acceleration in the direction of 3 degrees of freedom measured by the acceleration sensor 32A, the acceleration sensors 32A, 3A
The acceleration (angular acceleration) in the rotation direction (around the Z axis) of the surface plate 6 on the XY plane is obtained from the two Y direction accelerations of 2C. In addition, two Zs of the acceleration sensors 32A and 32B are used.
From the directional acceleration, the angular acceleration (around the Y axis) on the ZX plane of the surface plate 6 is obtained, and the acceleration sensors 32B and 32D are obtained.
The angular acceleration (around the X axis) on the ZY plane of the surface plate 6 can be obtained from the two accelerations in the Z direction. That is, the acceleration sensors 32A to 32D detect the acceleration of the exposure apparatus main body 30 in the directions of 6 degrees of freedom.

Since the acceleration is the second differential of the displacement, the acceleration may be calculated from the outputs of displacement sensors 33A to 33C described later without providing the acceleration sensors 32A to 32D. Conversely, the displacement sensors 33A to 33C may be omitted and the outputs of the acceleration sensors 32A to 32D may be integrated to obtain the displacement. Also, the acceleration sensor 3
A speed sensor may be provided instead of 2A to 32D.

Further, the base frame 2 has the −X direction and +.
At the respective ends in the X direction, "U-shaped" columns 4A and 4B that can be regarded as substantially rigid bodies are planted. A voice coil motor type actuator 31A is installed near the end of the upper plate of the support column 4A in the -Y direction. By controlling the current to the stator formed of the coil built in the actuator 31A, a biasing force in the + Y direction or the −Y direction is applied to the mover 35A formed of the magnetic body fixed to the upper plate of the first column 24. Can be given. Similarly, an actuator 31B similar to the actuator 31A is installed near the end of the upper plate of the column 4B in the -Y direction, and is installed at the end of the upper plate of the first column 24 in the -Y direction. A biasing force in the + Y direction or the −Y direction is applied to the mover 35B. Further, an actuator 31C is provided substantially in the center of the upper plate of the column 4B, and the mover 34 made of a magnetic body is fixed to the side surface of the first column 24 corresponding to the actuator 31C. It is configured to give a biasing force in the X direction. The actuators 31A to 31C are controlled by the first control unit 11 or the second control unit 12 via the switching unit 14, respectively, and correspond to the actuators 31A to 31C by the first control unit 11 or the second control unit 12. Mover 35
The urging force to A, 35B and 34 is controlled. In this example,
The actuators 31A and 31B control the displacement of the exposure apparatus main body 30 in the Y direction and the rotation angle around the Z axis, and the actuator 31C controls the displacement in the X direction.

A displacement sensor 33A for detecting displacements of the first column 24 in the X, Y, and Z directions is installed at the end of the upper plate of the column 4A in the -Y direction. There is. Similarly, a displacement sensor 33B for detecting the displacement of the first column 24 in each of the Y direction and the Z direction is installed at the end of the upper plate of the support column 4B in the -Y direction. A displacement sensor 33C for detecting the displacement of the first column 24 in the Z direction is installed at the end in the + Y direction. These three displacement sensors 33A to 33C
The detection result of is supplied to the first control unit 11. Similarly, when the mechanical constant of the exposure apparatus main body 30 is obtained, the detection results of these displacement sensors 33A to 33C are calculated by the calculation unit 1.
4 is supplied. The first column 24 is planted on the surface plate 6, and the displacement of the first column 24 is detected as the displacement of the surface plate 6.

The displacement sensor 33A detects the displacement of the surface plate 6 in the directions of three degrees of freedom, and from the measured values of the two displacements in the Y direction of the displacement sensors 33A and 33B, the (Z axis) on the XY plane of the surface plate 6 is detected. The rotation angle (around) is determined. Further, the rotation angle of the surface plate 6 on the XZ plane is obtained from the measured values of the displacements of the displacement sensors 33A and 33B in the Z direction, and is determined from the measured values of the displacements of the displacement sensors 33B and 33C in the Z direction. The rotation angle of the board 6 on the YZ plane is obtained. That is, the displacement sensors 33A to 33C detect the displacement of the surface plate 6 in the direction of six degrees of freedom. As the displacement sensors 33A to 33C, for example, a potentiometer having a resolution of about 0.1 mm, a photoelectric linear encoder, or the like can be used.

Next, the operation of the vibration isolator of this example will be described. In this example, a predetermined drive signal is input to a predetermined actuator prior to the actual operation, and the posture variation and vibration of the exposure apparatus main body 30 due to the drive of the actuator are monitored. FIG. 3 shows a simplified operation model of the image stabilizing apparatus of this example. In FIG. 3, an operation model for controlling displacement (vibration) of the exposure apparatus main body 30 of FIG. 1 in the Z direction is shown. ing. Furthermore, the displacement sensor 33A of FIG.
Also, the acceleration sensor 32A is shown built in the exposure apparatus main body 30. Since a speed sensor may be used instead of the acceleration sensor 32A as described above, the following description will be made on the assumption that speed or acceleration is detected. In FIG. 3, the model in the dotted rectangle shows the vibration absorbing system 5A of the vibration isolation mount 3A of FIG. The vibration absorbing system 5A includes a spring buffer system B including a spring K (for example, an air spring is used).
A buffer system including K and a fluid buffer system RK composed of a viscous fluid D such as oil for a damper filled in a predetermined container CA. In this case, first, the switching unit 14 switches from the first control unit 11 to the second control unit 12, and a predetermined drive signal is output from the second control unit 12 via the switching unit 14 to the actuator 7A. It In this case, the drive signal of the second control unit 12 is also supplied to the arithmetic unit 14 via the switching unit 14, and the drive signal is stored in the arithmetic unit 14. The exposure apparatus main body 30 is displaced in the Z direction corresponding to the thrust force of the actuator 7A based on the drive signal from the second control unit 12. In FIG. 3, the exposure apparatus main body 30 is displaced in the Z direction by D _ZA at the position where the displacement sensor 33A is installed. The displacement amount D _{ZA in the} Z direction is supplied from the displacement sensor 33A to the calculation unit 13, and the displacement amount D _ZA is stored in the calculation unit 13. At the same time, the acceleration sensor 32A supplies data of the velocity V _{ZA in} the Z direction or the acceleration G _ZA of the exposure apparatus main body 30 at the position where the acceleration sensor 32A is installed to the calculation unit 13, and these data are calculated.
3 is stored.

In practice, the exposure from the displacement sensor 33A is
Displacement amount D of the device body 30 in the X direction_XA, And displacement in Y direction
Amount D_YAData of the acceleration sensor is also supplied to the calculation unit 13.
Speed V in the X direction from 32A_XAOr acceleration G_XA, And Y
Speed V_YAOr acceleration G _YAIs also supplied to the calculation unit 13.
You. In addition, from the displacement sensor 33B, Y at that position
Displacement amount D_YBAnd Z displacement amount D_ZBData of
It is supplied to the calculation unit 13, and the
Displacement D in the Z direction_ZCIs supplied to the calculation unit 13.
You. Furthermore, from the other acceleration sensors 32B to 32D,
V speed in Z direction_ZBOr acceleration G_ZB, Y direction speed
V_YCOr acceleration G_YC, And velocity V in Z direction_ZDOr acceleration
G_ZDIs supplied to the calculation unit 13. All those data
It is stored in the calculation unit 13.

The same operation is repeated for different thrusts of the actuator 7A by the drive signal of the second controller 12, and the calculator 13 causes the exposure unit main body 30 to be displaced by a plurality of different drive signals to the actuator 7A.
Alternatively, acceleration data is supplied and these data are stored. The same operation is performed for the displacements of the five degrees of freedom, the detection data thereof are supplied to the calculation unit 13, and the detection data are stored in the calculation unit 13. After completion of the series of sequences, the calculation unit 13 accurately determines the center of gravity of the exposure apparatus main body 30, the weight, the moment of inertia (when controlling the rotation angle), and mechanical constants such as the principal axis of inertia, based on the supplied measurement data. Ask for.

FIG. 4 shows an example of the simplest one-mass system vibration model for obtaining the mechanical constants corresponding to the operation model of FIG. 3. In this example, the support CL to the exposure apparatus main body 3 is used.
A mass point M corresponding to 0 is suspended via a fluid buffer system RK including a viscous fluid D filled in a predetermined container CA and a spring buffer system BK including a spring K. The components in this example are a mass point M, a spring K, and a viscous fluid D, the characteristics of which are determined by the mass m, the spring constant k, and the viscosity coefficient c, respectively. When a force F is applied to the mass point M from outside in this vibration model, for example, downward (−Z direction), the mass point M vibrates up and down with a gradually changing displacement d.

FIGS. 5 (a) to 5 (c) show how the mass M oscillates when the initial displacement is commonly d _{0 and} at three different damping ratios. Figure 5
In (c), the horizontal axis represents time t and the vertical axis represents displacement d. FIG. 5A shows the case where the damping ratio h is 0.05, and the curve 36 representing the vibration does not easily converge because the damping ratio h is relatively small. Further, in FIG. 5B, the damping ratio h is 0.1
However, since the damping ratio h is larger than that in the case of FIG. 5A, the curve 37 representing the vibration converges relatively quickly. Then, as shown in FIG. 5C, when the damping ratio h is 0.2, the curve 38 representing the vibration converges extremely quickly because the damping ratio h is relatively large.

As shown in FIGS. 5 (a) to 5 (c) above, the convergence state of the vibration of the mass M differs depending on the damping ratio h. In this case, if the mass m of the mass point M is known, the spring constant k and the viscosity coefficient c can be calculated back from this amplitude fluctuation. On the contrary, if the spring constant k and the viscosity coefficient c are known, the mass m can be calculated. In the case of an actual exposure apparatus, the vibration system is more complicated, and the degree of freedom and the translational component as well as the rotational component must be considered. The vibrating object also becomes a structure having a moment of inertia instead of a mass point. However, if the vibration constants of the vibration isolation mounts 7A to 7D that support the exposure apparatus main body 30 are accurately known by monitoring the vibration states of all degrees of freedom including the rotation component as in this example. , Not only can the mass and moment of inertia be obtained in the same manner as the vibration model of FIG.
It is also possible to obtain mechanical constants such as the position of the center of gravity and the principal axis of inertia. In this example, the mechanical constants obtained by the above method are used to obtain the parameters for determining the drive amount (thrust) of each actuator in the calculation unit 13 of FIG. . Specifically, the displacement sensors 33A to
The gain for setting the drive signals of the actuators 7A to 7D and 31A to 31C is obtained as a parameter from the outputs of 33C and the acceleration sensors 32A to 32D.

The above calculation results are supplied from the arithmetic unit 13 to the first control unit 11 based on the instruction of the first control unit 11, and are stored in the storage device of the first control unit 11. Then, during the actual operation, the first control unit 11 calculates the drive signal (thrust) of each actuator from the output of each sensor based on the supplied parameters, and controls the operation of each actuator based on the result. The mechanical constants obtained by the above series of sequences are actually measured values, and the parameters of the thrust generated by the actuator are calculated by applying these numerical values, so that the vibration of the exposure apparatus main body 30 can be suppressed at a higher level than in the past. It can be carried out.

Next, an example in which the method of this example is applied during actual operation will be described. The first application method is to perform the above-mentioned series of sequences only once immediately after all the elements of the exposure apparatus are assembled, and determine the mechanical constants such as weight, center of gravity, moment of inertia, and principal axis of inertia. , Determines the parameters for determining the thrust generated by the actuator. The determined mechanical constants and parameter values are stored in the storage device of the first controller 11, and are used by the first controller 11 when calculating the drive amount of each actuator. However, in this case, it is necessary to incorporate the same sequence as in this example when the exposure apparatus is modified or added with some element.

The second application method is to incorporate the sequence of this example into the initialization operation when the power of the exposure apparatus is turned on. Thereby, when calculating the thrust of the actuator, the parameters for each actuator can be used by the first controller 11 without having to worry about the change in the device state. The third application method has a plurality of parameters corresponding to a plurality of positions of movable parts such as the reticle stage 27 of the exposure apparatus body 30 and the wafer stage 20. For example, the weight of stage parts such as the reticle stage 27 and the wafer stage 20 is about several tens kg to hundreds of tens kg, and accounts for several% of the total weight of the exposure apparatus main body 30. Therefore, when considering a precise level of vibration suppression, it is by no means negligible. Therefore, for example, regarding the wafer stage 20, each parameter is calculated for the movement range of all stages,
It is preferable to store those parameters, but it is not realistic considering the time and the amount of storage for obtaining such enormous data. However, in the case of an exposure apparatus to which this example is applied, it is the moment of exposure that each parameter is actually required accurately. Therefore, it is only necessary to know the parameters when each shot area on the wafer 22 is set as the exposure area of the projection optical system 25. For example, in the case of an 8-inch wafer, the number of shot areas is at most 7
It is about 0, which is sufficiently realistic.

The parameters for determining the drive amount of each actuator obtained in this example are the wafer stage 2
It is measured corresponding to the position coordinate of 0, that is, the stage coordinate system. Therefore, by expressing each parameter in the first and second application methods by an appropriate function of the stage coordinate system, and measuring and calculating each parameter corresponding to the first and second application methods, If the coefficient value for determining the function is accurately calculated, it is not necessary to store a large amount of data in the storage unit as in the third application method, and the parameter corresponding to the stage position based on the function is used. The calculation should be performed each time.

Next, the operation when the parameters obtained by the above calculation method and application method are applied to actual operation will be described. In this case, the switching unit 14 is switched so that the operation of each actuator can be controlled by the first control unit 11. As shown in FIGS. 1 and 2, information on the acceleration of 6 degrees of freedom detected by the acceleration sensors 32A to 32D on the first column 24 and information on the displacement of 6 degrees of freedom measured by the displacement sensors 33A to 33C. Are supplied to the first controller 11. The data regarding the parameters of the drive amount of the actuator obtained by the above-described first to third application methods is supplied to the first control unit 11, and the first control unit 11 is based on those parameters. The acceleration and displacement of 6 degrees of freedom are 0
As shown in FIG.
Two actuators 31A, 31 for 7D and Y directions
One actuator 31C for B and X axes is driven. As a result, the six degrees of freedom of the exposure apparatus main body 30 on the surface plate 6 can be quickly stopped.

Although the present invention is applied to the stepper type projection exposure apparatus in the above-described example, the present invention can also be applied to a step-and-scan type scanning exposure type projection exposure apparatus. In particular, in the scanning exposure type, a large acceleration is generated at the start of the scanning exposure, so that the active type vibration damping device including the actuator for stopping the swing of the surface plate 6 as in this example is effective.

The present invention is not limited to the above-mentioned embodiments, and various configurations can be adopted without departing from the gist of the present invention.

[0037]

According to the control method of the vibration isolator according to the present invention, the vibration isolation target is vibrated by using the actuator originally used for vibration suppression, and the response output of the detection sensor is fetched. The mechanical constant of the vibration-proof object can be accurately obtained. Therefore, there is an advantage that the anti-vibration device can be controlled with high accuracy based on the accurate mechanical constants of the anti-vibration object. In addition, there is also an advantage that no special measuring device for obtaining the mechanical constant of the vibration-proof object is required.

Further, in the case of determining the parameter for obtaining the drive amount of the actuator from the output of the detection sensor based on the obtained mechanical constant and controlling the operation of the actuator by using the determined parameter, An accurate parameter for determining the drive amount of the actuator is obtained based on an accurate mechanical constant, and as a result, the residual vibration generation amount can be suppressed to almost zero.

Further, when the mechanical constants of the vibration isolation target and the parameters are determined at the time of initialization of the control of the vibration isolation device, even if the state of the vibration isolation target changes, the optimum vibration isolation is performed. There is an advantage that shaking can be performed. Further, according to the vibration isolator of the present invention, the above-described control method of the vibration isolator of the present invention can be applied, and highly accurate vibration isolation performance can be obtained based on accurate mechanical constants.

[Brief description of drawings]

FIG. 1 is a perspective view showing an overall schematic configuration of a projection exposure apparatus used in an example of an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

3 is a diagram showing a simplified operation model of a vibration isolation device provided in the projection exposure apparatus of FIG.

FIG. 4 is a diagram showing a vibration model of a one-mass system corresponding to the behavior model of FIG.

5 is a diagram for explaining a change in vibration of a mass point M when a damping ratio changes in the vibration model of FIG.

[Explanation of symbols]

 2 Base Frame 3A to 3D Anti-Vibration Mount 6 Surface Plate 7A to 7D, 31A to 31C Actuator 11 First Control Unit 12 Second Control Unit 13 Computing Unit 20 Wafer Stage 22 Wafer 27 Reticle Stage 28 Reticle 30 Exposure System Main Body 32A to 32D Acceleration sensor 33A to 33C Displacement sensor

Claims (4)

[Claims] 1. A plurality of anti-vibration mounts for supporting an anti-vibration object on an installation surface, a detection sensor for detecting a posture and a motion state of the anti-vibration object, and the anti-vibration apparatus based on an output of the detection sensor. An actuator for controlling the vibration of an object to be shaken, and a method for controlling an anti-vibration device, comprising: driving the actuator by a predetermined amount to vibrate the object to be shaken to capture the response output of the detection sensor; A method for controlling an image stabilization device, wherein a mechanical constant of the image stabilization target is obtained based on the relationship between the drive amount of the image sensor and the response output of the detection sensor. 2. The method for controlling an anti-vibration device according to claim 1, wherein a parameter for determining the drive amount of the actuator is determined from the output of the detection sensor based on the obtained mechanical constant, A method for controlling an image stabilization device, which comprises controlling the operation of the actuator using the determined parameter. 3. The method for controlling a vibration isolation device according to claim 2, wherein the calculation of the mechanical constant of the vibration isolation target and the determination of the parameter are performed at the time of initialization of the control of the vibration isolation device. A method for controlling an anti-vibration device. 4. A plurality of anti-vibration mounts for supporting an anti-vibration object on an installation surface, a detection sensor for detecting a posture and a motion state of the anti-vibration object, and the anti-vibration apparatus based on an output of the detection sensor. An anti-vibration device having an actuator for controlling vibration of an object to be vibrated, comprising: first control means for controlling a driving amount of the actuator based on an output of the detection sensor and a predetermined parameter; and an output of the detection sensor. Second control means for controlling the drive amount of the actuator irrespective of the above, and the vibration control target object based on the response output of the detection sensor when the actuator is driven by a predetermined amount via the second control means. Calculating means for obtaining a mechanical constant and determining the value of the predetermined parameter for determining the drive amount of the actuator from the output of the detection sensor from the mechanical constant; An anti-vibration device comprising: