JPH10270308A - Vibration absorbing device and stepper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of heat by an actuator of a vibration absorbing device because of constant interference acting upon the vibration absorbing device. SOLUTION: A vibration absorbing system 11 for controlling vibration of a stepper body 40 drives and controls actuators 7A-7D and 32A-32C according to output from a displacement sensor 10 and a vibration absorbing substrate 11 and controls vibration of vibration absorbing table. When a high vibration absorbing capacity is required against a displacement caused by a constant disturbance such as tension of cable, vibration absorption is performed by a normal feed-back control. When such a high vibration absorbing capacity is not needed, displacement signals in a given area are prevented from being fed back to a vibration absorbing loop by correcting blocks 1000a-1000f. In this way, the constant disturbance is removed and a steady thrust of the actuators 7A-7D and 32A-32C is not generated and generation of heat can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration apparatus and an exposure apparatus, and more particularly, to a so-called active type anti-vibration apparatus in which an anti-vibration table is driven by an actuator so as to cancel the vibration of the anti-vibration table. The present invention relates to an exposure apparatus provided with a vibration isolator.

[0002]

2. Description of the Related Art With the advancement of precision equipment such as a step-and-repeat type reduction projection type exposure apparatus, that is, a so-called stepper, a micro-vibration acting on a surface plate (anti-vibration table) from an installation floor is micro-G. There is a need for isolation at the level. Various types of vibration-damping pads, such as mechanical dampers or pneumatic dampers containing compression coil springs in the damping liquid, are used as vibration-damping pads for supporting the vibration-damping table of the vibration-damping device. ing. In particular, an air spring anti-vibration device having a pneumatic damper can be set to a small spring constant and insulates vibrations of about 10 Hz or more, and is therefore widely used for supporting precision equipment. Recently, in order to overcome the limitations of conventional passive vibration isolators,
An active anti-vibration device has been proposed (for example, see Japanese Patent Application No. 7-83577, etc., of the same applicant as the present application). This is an anti-vibration device that detects the vibration of the anti-vibration table with a sensor and controls the vibration by driving the actuator based on the output of this sensor. Ideal vibration with no resonance peak in the low frequency control band It can have an insulating effect.

[0003]

However, when a steady disturbance acts on the above-described active vibration isolator, for example, a steady force is generated due to the elastic force of the cable connecting the stepper body or the like to the peripheral device, or its own weight. In order to maintain the position of the stepper body by correcting even a slight displacement caused by these disturbances, a steady thrust is generated in a direction to cancel the disturbance to the actuator constituting the active vibration damping device. And When the actuator is of an electromagnetic type, the steady current for generating the steady thrust causes local heat generation from the actuator.

Further, the stepper and the like are housed in a chamber maintained at a constant temperature and humidity to maintain the accuracy. However, as described above, when local heat is generated from the actuator, the air in the chamber is removed. Produces fluctuation. Due to this fluctuation, for example, the measurement accuracy of a laser interferometer or the like that measures the amount of movement of the XY stage may be reduced.

An object of the present invention is to suppress disturbance vibration (vibration suppression).
Provided is an anti-vibration apparatus capable of preventing local heat generation from an actuator even when there is a steady disturbance such as a cable tension and maintaining high accuracy, and an exposure apparatus having the same. It is in.

[0006]

FIG. 1 shows an embodiment of the present invention.
The present invention will be described with reference to FIG. (1) An anti-vibration device according to the first aspect of the present invention includes an anti-vibration table 6 held via pads 4A to 4D (pad 4D is not shown); an actuator 7A for driving the anti-vibration table 6
To 7D, 32A to 32C (actuators 7C and 7C)
D is not shown) and; displacement sensor 10Z detecting the displacement of the anti-vibration table _{6 1 ~10Z 3, 10Y 1 ~10Y} 2, 10X and; anti-vibration table 6 vibration sensor 5Z ₁ ~5Z ₃ for detecting vibration of 5Y ₁
~5Y _2, 5X and; displacement sensor 10Z ₁ ~10Z _3, 10
Y ₁ ~10Y _2, a position control loop based on the output of the 10X, suppresses displacement and vibration of the anti-vibration table in the vibration sensor _{5Z 1 ~5Z 3, 5Y 1 ~5Y} 2, 5X of the speed control loop based on the output Actuators 7A to 7D, 32A
; And a vibration control system 11 for driving and controlling ～32C, displacement sensor _{10Z 1 ~10Z 3, 10Y 1 ~10Y} 2, 10X
The above object is achieved by providing a dead zone of a predetermined width that can be selected to be valid or invalid for the output of the position control loop. (2) The invention according to claim 2 provides the pads 4A to 4D
(The pad 4D is not shown) and the vibration isolation table 6 is held
And actuators 7A to 7D for driving the vibration isolation table 6, 3
2A~32C and (actuator 7C and 7D not shown), displacement sensor 10Z ₁ for detecting the displacement of the anti-vibration table 6
_{~10Z 3, 10Y 1 ~10Y 2,} 10X and; anti-vibration table vibration sensor 5Z ₁ ~5Z ₃ for detecting vibration of 6, 5Y ₁ to 5
Y _2, 5X and; displacement sensor 10Z ₁ ~10Z _3, 10Y ₁
～10Y _2, a position control loop based on the 10X output, so as to suppress the displacement and vibration of the anti-vibration table 6 by the vibration sensor _{5Z 1 ~5Z 3, 5Y 1 ~5Y} 2, 5X of the speed control loop based on the output Actuators 7A to 7D, 32A to 3
; And a vibration control system 11 for driving and controlling 2C, provided with the displacement sensor _{10Z 1 ~10Z 3, 10Y 1 ~10Y} 2, 10X position control loop a dead zone to the output of the dead zone width of the dead band and variable Things. (3) According to the third aspect of the present invention, the pattern formed on the mask R is transferred to the substrate stage 20 via the projection optical system PL.
3. An exposure apparatus for transferring an image onto an upper substrate W.
Of the present invention.

[0007] In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments of the present invention are used for easy understanding of the present invention. However, the present invention is not limited to this.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows steps according to an embodiment.
FIG. 1 shows a schematic perspective view of an AND-scan type exposure apparatus 100. In FIG. 1, a rectangular plate-shaped pedestal 2 is installed on a floor as an installation surface, and vibration isolation pads 4A to 4D are provided on the pedestal 2 (however, in FIG. 1, the vibration isolation pad 4D on the back side of the paper is not shown). ) Are installed, and these vibration isolation pads 4A
A rectangular surface plate 6 as an anti-vibration table is installed on 4D to 4D. Here, as will be described later, in the present embodiment, the projection optical system PL is used, so the Z axis is taken in parallel with the optical axis of the projection optical system PL, and the surface plate 6 is set in a plane orthogonal to the Z axis.
The X axis is taken in the longitudinal direction and the Y axis is taken in a direction perpendicular to the X axis. Also, the rotation directions around the respective axes are Zθ, Xθ,
Defined as Yθ direction. In the following description, directions indicated by arrows indicating the X, Y, and Z axes in FIG. 1 are indicated by + X, + Y, + Z directions, and directions opposite thereto are indicated by -X,-, as necessary.
It shall be used separately from the Y and -Z directions.

Each of the vibration isolation pads 4A to 4D has a surface plate 6
Are arranged near the four corners of the bottom surface of the rectangle. In the present embodiment, pneumatic dampers are used as the vibration isolation pads 4A to 4D, and the vibration isolation pads 4A to 4
Since the height of D can be adjusted, the pneumatic damper also serves as a vertical movement mechanism. Of course, a mechanical damper or the like in which a compression coil spring is put in the damping liquid by providing a vertical movement mechanism separately may be used as the vibration isolation pad.

An actuator 7A is installed between the pedestal 2 and the surface plate 6 in parallel with the vibration isolation pad 4A. The actuator 7A includes a stator 9A fixed on the pedestal 2 and a mover 8A fixed on the bottom surface of the surface plate 6, and receives an instruction from a control device 11 (not shown in FIG. 1, see FIG. 3). Accordingly, an urging force in the Z direction from the pedestal 2 to the bottom surface of the surface plate 6 or a suction force from the bottom surface of the surface plate 6 toward the pedestal 2 is generated. In the other vibration isolation pads 4B to 4D, the actuators 7B to 7 are connected in parallel similarly to the vibration isolation pad 4A.
D (although the actuators 7C and 7D on the back side of the paper are not shown in FIG. 1), these actuators 7
The biasing force or suction force of B to 7D is also controlled by the control device 11 respectively.
(Not shown in FIG. 1, see FIG. 3). The control method of the actuators 7A to 7D will be described later.

Next, a specific configuration of the actuator 7A will be described with reference to FIG.

FIG. 2A shows an example of the configuration of the actuator 7A. In FIG. 2 (a), the stator 9A has an S-pole shaft 9Ab on both sides of an N-pole shaft 9Aa.
It consists of a magnet on which 9Ac is formed. The mover 8A includes an inner cylinder 12 loosely fitted on the shaft 9Aa, a coil 13 wound around the outer side of the inner cylinder 12, and an outer cylinder 14 covering the coil 13. By adjusting, between the stator 9A and the mover 8A,
A force is generated in a direction (± Z direction) parallel to the axis 9Aa.

FIG. 2B shows another example of the actuator 7A. In FIG. 2B, a stator 16 made of a magnetic material is fixed to the first member 15 and the second member 17 is fixed.
The inner cylinders 18A and 18B are fixed so as to sandwich the stator 16 therebetween, and the coils 1 are respectively provided outside the inner cylinders 18A and 18B.
9A and 19B are wound. Also in this case, by adjusting the current flowing through the coils 19A and 19B, the balance of the attraction force between the first member 15 and the second member 17 is changed to generate a force. Other actuator 7B
7D are configured similarly to the actuator 7A.

Returning to FIG. 1, acceleration sensors 5Z ₁ and 5Z ₂ as vibration sensors for detecting Z-direction acceleration of the surface plate 6 are attached to the side surface of the surface plate 6 on the + Y direction side. An acceleration sensor 5Y ₁ as a vibration sensor for detecting the Y-direction acceleration of the surface plate 6 is provided at an end of the surface of the surface plate 6 in the + Y direction.
5Y ₂ is attached, in the + X direction end portion of the plate 6 upper surface is mounted an acceleration sensor 5X as a vibration sensor for detecting the X-direction acceleration of the base plate 6. These acceleration sensors _{5Z 1, 5Z 2, 5Y 1} , 5Y 2, 5X, for example, a semiconductor type acceleration sensor is used. These acceleration sensors _{5Z 1, 5Z 2, 5Y 1} , 5Y 2, 5X output also control device 11 (not shown in FIG. 1, see FIG. 3) is supplied to the.

[0016] In addition, the side surface of the + Y direction side of the base plate 6, a rectangular metal plate having a predetermined area (conductive material) 23 _1, 23 ₂ is attached. Displacement sensor in the present embodiment, to detect the non-conductive material and has a ceramic plate is used which is, Y-direction displacement of the surface plate at a position opposite to the metal plate 23 _1, 23 ₂ as the base plate 6 10Y ₁ and 10Y ₂ (not shown in FIG. 1 to avoid complicating the drawing; see FIG. 3). As these displacement sensors 10Y ₁ and 10Y ₂ , for example, eddy current displacement sensors are used. According to this eddy current displacement sensor, an AC voltage is applied to a coil wound on an insulator in advance, and when the sensor approaches an object to be measured made of a conductive material (conductive material), the AC magnetic field generated by the coil causes the AC magnetic field to be applied to the conductive material. An eddy current is generated, and the magnetic field generated by the eddy current is in the opposite direction to the magnetic field created by the coil current, and these two magnetic fields overlap to affect the output of the coil, and the current flowing through the coil The intensity and phase change. This change becomes larger as the measurement object is closer to the coil, and becomes smaller as the measurement object is farther from the coil.
You can know the displacement. In addition, as a displacement sensor, a capacitance-type non-contact displacement that detects the distance between the sensor and the measurement object in a non-contact manner by utilizing that the capacitance is inversely proportional to the distance between the electrode of the sensor and the measurement object A sensor may be used. If the configuration is such that the influence of the background light can be prevented, a PSD (semiconductor optical position detector) can be used as the displacement sensor.

Further, in the + Y direction end portion of the plate 6 upper surface is affixed a metal plate 23 _3, 23 ₄ of a predetermined area. These metal plates 23 _3, 23 ₄ opposed to consist eddy current displacement sensor for detecting displacement in the Z direction of the platen 6 by the displacement sensor 10Z
₁ , 10Z ₂ (not shown in FIG. 1, see FIG. 3). Further, in the + X direction side of the base plate 6 upper surface pasted metal plate 23 ₅ having a predetermined area, consisting of an eddy current displacement sensor for detecting the X-direction displacement of the base plate 6 to face the metal plate 23 ₅ Displacement sensor 10X (not shown in FIG. 1, FIG. 3
Reference). Similarly, the displacement sensor 10
The outputs of Y ₁ , 10Y ₂ , 10Z ₁ , 10Z ₂ , and 10X are also supplied to the control device 11 (not shown in FIG. 1, see FIG. 3).

An XY as a substrate stage driven in two-dimensional XY directions by driving means (not shown)
The stage 20 is mounted. Further, a wafer W as a photosensitive substrate is suction-held on the XY stage 20 via a Z leveling stage, a θ stage (both not shown) and a wafer holder 21. Further, a first column 24 is planted on the surface plate 6 so as to surround the XY stage 20, and a projection optical system PL is provided at the center of the upper plate of the first column 24.
Is fixed, and a second column 26 is implanted on the upper plate of the first column 24 so as to surround the projection optical system PL.
A reticle R as a mask is placed via a reticle stage 27 at the center of the upper plate.

The moving position of the XY stage 20 in the Y direction is
The movement position of the XY stage 20 in the X direction is measured by the Y-axis laser interferometer 30Y as a position measurement unit.
The measurement is performed by an X-axis laser interferometer 30X as a position measuring means, and the outputs of these laser interferometers 30Y and 30X are input to the controller 11 (see FIG. 3) and a main controller (not shown). ing. The Z-leveling stage is configured so that the drive in the Z-axis direction and the tilt with respect to the Z-axis can be adjusted, and the θ-stage is configured to be capable of minute rotation about the Z-axis. Therefore, the XY stage 20, Z
The wafer W is moved by the leveling stage and the θ stage.
Can be positioned three-dimensionally.

The reticle stage 27 is a reticle R Y
Fine adjustment in the axial direction and adjustment of the rotation angle are possible. The reticle stage 27 is driven in the X direction by driving means (not shown), and the position of the reticle stage 27 in the X direction is measured by a reticle laser interferometer 30R as position measuring means. The output of the laser interferometer 30R is also input to the controller 11 (see FIG. 3) and a main controller (not shown).

Further, an illumination optical system (not shown) is arranged above the reticle R, and a main controller (not shown) performs relative positioning (alignment) between the reticle R and the wafer W.
The image of the pattern of the reticle R via the projection optical system PL is sequentially transmitted to each shot area of the wafer W under the illumination light EL for exposure from the illumination optical system while performing autofocus by a focus detection system (not shown). It is designed to be exposed. In the present embodiment, when exposing each shot area, the XY stage 20 and the reticle stage 27 are relatively scanned by the main controller at a predetermined speed ratio along the X-axis direction (scanning direction) via respective driving means. Is done.

The first column 24 has four legs 24a to 2a.
4d (however, the leg 24d on the back side of the drawing is not shown in FIG. 1) and is installed on the surface plate 6. + On the leg 24b
The side surface of the X direction, an acceleration sensor 5Z ₃ is attached for detecting an acceleration in the Z direction of the first column 24. As the acceleration sensor 5Z _3, for example a piezo-resistive or capacitive semiconductor type acceleration sensor is used. The output of the acceleration sensor 5Z ₃ also control device 11
(Not shown in FIG. 1, see FIG. 3). In addition, at the + Y direction end of the upper plate upper surface of the first column 24 and +
The corner portion serving as the X-direction end portion, the metal plate 23 ₆ having a predetermined area is adhered. The metal plate 23 ₆ displacement sensor 10Z ₃ consisting of an eddy current displacement sensor for detecting the Z-direction displacement of the first column 24 to face the (not shown in FIG. 1, see FIG. 3) is provided.

Further, a pin 35A is embedded in a side surface of the first column 24 in the -X direction, and an actuator 32A is provided between the pin 35A and a column (not shown) fixed on the floor.
Is attached. Like the actuator 7A, the actuator 32A includes a stator 34A made of a magnet and fixed to a support (not shown) and a mover 33A including a coil attached to a pin 35A. By adjusting the current flowing through the inner coil, a force can be applied to the pin 35A in the ± Y direction. Similarly, a pin 35B is embedded in a side surface of the first column 24 in the + X direction, and an actuator 32B having the same configuration as the actuator 32A is mounted between the pin 35B and a column (not shown) fixed on the floor. A force can be applied to the pin 35B in the ± Y direction in accordance with an instruction from 11. Further, an actuator 32A is provided between the central portion of the side surface in the + X direction of the first column 24 and a support (not shown) on the floor.
An actuator 32C having the same configuration as that described above is provided, and a force can be applied to the first column 24 in the ± X direction via the actuator 32C according to an instruction from the control device 11. Actuators 32A-3 by control device 11
The 2C control method will also be described later.

Here, the surface plate 6 when the exposure apparatus 100 is installed
Briefly the height and the adjustment of the horizontal level of the displacement sensor 10Z _1, 10Z _2, Z-direction displacement (height) of the base plate 6, which is measured by 10Z ₃ to control the vibration-isolating pad 4A~4D not shown (Not shown), and based on these data, the control system of the vibration isolation pads 4A to 4D
The height of each of the anti-vibration pads 4A to 4D for keeping the horizontal level at a predetermined value and calculating the height is calculated. Thereafter, the control system sets the heights of the vibration isolation pads 4A to 4D to the calculated heights. Thereafter, the heights of the vibration isolation pads 4A to 4D are respectively maintained at the set values. Accordingly, the surface plate 6 is not distorted, and the positioning accuracy of the XY stage 20 on the surface plate 6 is maintained with high accuracy.

In this embodiment, the exposure main body 40 (see FIG. 3) is constituted by the surface plate 6, the XY stage 20, the wafer holder 21, the first column 24, the projection optical system PL, the second column 26, the reticle stage 27 and the like. Is configured.

Next, a control system of the actuators 7A to 7D and 32A to 32C for removing the vibration of the exposure main body 40 will be described with reference to the block diagram of FIG.

The control device 11 includes displacement sensors 10Z ₁ , 1
_{0Z 2, 10Z 3, 10Y 1} , 10Y 2, 10X and the acceleration sensor _{5Z 1, 5Z 2, 5Z 3} , 5Y 1, 5Y 2, suppress the vibration of the exposure main body portion 40 which includes a base plate 6 on the basis of 5X output Actuators 7A, 7B, 7C, 7D, 3
A vibration control system that drives and controls the 2A, 32B, and 32C is configured.

More specifically, the vibration control system includes a first coordinate converter 42 and six subtractors 46a to 46f.
, Six correction blocks 1000a to 1000f, and position controllers XPI, YPI, ZPI, XθPI, Y
θPI, ZθPI, and six speed conversion gains 52a-5
2f, a second coordinate transformation unit 48, and six integrators 50a
To 50f, six subtractors 54a to 54f, speed controllers VXPI, VYPI, VZPI, VXθPI,
VYθPI, VZθPI, decoupling calculation unit 56, 7
Thrust gains 58a to 58g. Then, the first coordinate conversion unit 42 outputs the displacement sensors 10Z ₁ , 10Z ₂ ,
The outputs of 10Z ₃ , 10Y ₁ , 10Y ₂ , and 10X are input through A / D converters (not shown), respectively, and the center of gravity of the exposure main body 40 has six degrees of freedom (X, Y, Z, Xθ, Y).
θ, Zθ: refer to FIG. 1) (x, y, z, θ _x ,
θ _y , θ _z ). The subtractors 46a to 46f are connected to the first
The displacement amounts (x, y, z, θ _x , θ _y , θ _z ) of the center of gravity in the directions of six degrees of freedom converted by the coordinate conversion unit 42 are output to the target value output unit 4.
The target value (x
₀ , y ₀ , z ₀ , θ _x0 , θ _y0 , θ _z0 ) and the positional deviation in each direction with six degrees of freedom (Δx = x ₀ −).
_{x, Δy = y 0 -y,} Δz = z 0 -z, Δθ x = θ x0 -
_{θ x, Δθ y = θ y0} -θ y, Δθ z = θ z0 -θ z) to be calculated. The correction blocks 1000a to 1000f are:
Position deviation Δx, Δ calculated by subtractors 46a to 46f
From y, Δz, Δθ _x , Δθ _y , and Δθ _z , the correction position deviations Δxc, Δyc, Δzc, Δθ in accordance with the processing procedure described later.
_x c, Δθ _y c, calculates the [Delta] [theta] _z c. Position controllers XPI, YPI, ZPI, XθPI, YθPI, ZθP
I is the correction position deviation Δxc, Δyc, Δzc, Δθ
_x c, consists of PI controller for each direction of the control operation of the six degrees of freedom [Delta] [theta] _y c, the [Delta] [theta] _z c as an operation signal. The speed conversion gains 52a to 52f are determined by the position controllers XPI, YPI, ZPI, XθPI, YθPI, Z
Output from θPI is speed command value x ₀ ′, y ₀ ′, z ₀ ′,
are converted to θ _x0 ′, θ _y0 ′, and θ _z0 ′, respectively. The second coordinate conversion unit 48 includes acceleration sensors 5Z ₁ , 5Z ₂ , 5Z ₃ ,
The outputs of 5Y ₁ , 5Y ₂ , and 5X are input via A / D converters (not shown), respectively, and the accelerations (x ″, y ″, z ″, θ _x ″, θ _y ″, and θ) of the center of gravity in the directions of six degrees of freedom are input. _z "). The six integrators 50a to 50f provide acceleration x ″ in the direction of six degrees of freedom of the center of gravity after conversion by the second coordinate conversion unit 48,
y ", z", [theta] _x ", [theta] _y ", [theta] _z "are respectively integrated, and the velocity x ', y', z 'of the center of gravity in each direction is calculated.
Convert to θ _x ′, θ _y ′, θ _z ′. Subtractors 54a-54
f is the speed command value converted by the speed conversion gain _{52a~52f x 0 ', y 0'} , z 0 ', θ x0', θ y0 ', θ z0'
From the outputs x ′, y ′, z ′, θ of the integrators 50a to 50f
_x ′, θ _y ′, θ _z ′ are respectively reduced to obtain velocity deviations (Δx ′ = x ₀ ′ −x ′, Δ) in the respective directions of six degrees of freedom.
y ′ = y ₀ ′ −y ′, Δz ′ = z ₀ ′ −z ′, Δθ _x ′ =
θ _x0 '-θ _x ', Δθ _y '= θ _y0 ' -θ _y ', Δθ _z ' = θ
_{z0 '-θ z')} is calculated. Speed controller VXP
I, VYPI, VZPI, VXθPI, VYθPI, V
ZθPI includes a subtractor speed deviation calculated in 54a~54f Δx ', Δy', Δz ', Δθ x', Δθ y ', Δ
It comprises a PI controller that performs a control operation using θ _z ′ as an operation signal. The decoupling calculation unit 56 performs decoupling calculation for converting the speed control amount calculated by the speed controller into a speed command value to be generated at each actuator position. The thrust gains 58a to 58g convert the speed command value to be generated at the position of each actuator after conversion by the decoupling calculation unit 56 into the thrust to be generated by each actuator.

That is, the vibration control system according to the present embodiment includes an acceleration sensor, an integrator, a speed controller, and the like as an inner loop inside a position control loop including a displacement sensor, a position controller, and the like. It is a multiple loop control system having a configured speed control loop.

In the position control loop in the multi-loop control system described above, the main body of the projection exposure apparatus (FIG.
When a steady force is applied to a portion above the surface plate 6 by a signal cable (not shown) or the like, the actuators are constantly operated to correct the displacement of the main body of the projection exposure apparatus caused by the steady force. Thrust is generated, which generates heat.

Here, considering the operation of the projection exposure apparatus, in a series of operations such as reticle loading, wafer loading, alignment, exposure, stage movement, etc., a high anti-vibration capability is not required during all operations. Therefore, when a very high anti-vibration capability is not required, by reducing the feedback amount based on the position deviation in the position control loop, it is possible to suppress the generation of the steady thrust and the heat generation from each actuator.

For example, during reticle loading,
When high anti-vibration performance is not required for projection exposure equipment,
In the position control loop in FIG.
Position deviations Δx, Δy, Δz, Δ obtained at 46f
As long as θ _x , Δθ _y , and Δθ _z are within predetermined values, these positional deviations need not be fed back. That is, a dead zone may be provided for these positional deviations. This example will be described with reference to FIGS.

FIGS. 4 to 6 are flow charts for explaining the processing constituting a part of the position control loop inside the control device 11 shown in FIG. In the flowchart shown in FIG. 4, the control device 11 determines in step S41 that
Position deviations Δx, Δy, Δz, Δθ _x , Δ according to operations such as reticle loading and exposure of the projection exposure apparatus shown in FIG.
It is determined whether or not dead zones are set for θ _y and Δθ _z . Then, when it is detected that a high vibration isolation capability is not required, that is, when it is determined that a dead zone can be set, the dead zone flag is set to 1 in step S42. Conversely, if it is detected in step S41 that an operation requiring a high vibration isolation capability is being performed, that is, if it is determined that the dead zone should not be set, the dead zone flag is set to 0 in step S43.

FIG. 5A shows the subtracters 46a to 46a in FIG.
46f and processing contents in the correction blocks 1000a to 1000c. First, in step S51, position deviations Δx, Δy, Δz, Δθ _x , Δθ _y , and Δθ _z are obtained (processing of the subtracters 46a to 46f. Hereinafter, in order to avoid complication of description, the position deviations Δx, Δy, Δ
z, Δθ _x , Δθ _y , Δθ _z are denoted as Δ). In step S52, the dead zone flag is checked. If the dead zone flag is 0, the correction position deviation Δ
_{xc, Δyc, Δzc, Δθ x} c, Δθ y c, Δθ z c
(Hereafter, to avoid complicating the description, if necessary corrected position deviation _{Δxc, Δyc, Δzc, Δθ x} c, Δθ y c,
Δθ _z c is displayed as Δc. ) Without any corrections,
In other words, the processing is completed with Δc = Δ, and the next processing block, that is, the position controllers XPI, YP
The correction position deviation Δc is sent to I, ZPI, XθPI, YθPI, and ZθPI.

If the dead zone flag is 1 in step S52, it is determined in step S54 whether the position deviation Δ is larger or smaller than a predetermined dead zone width Wdz. If the position deviation Δ is smaller than the dead zone width Wdz, the process is ended by setting the corrected position deviation Δc to 0 in step S54 and FIG.
Position controllers XPI, YPI, ZPI, Xθ
The correction position deviation Δc is sent to PI, YθPI, and ZθPI.

If the position deviation Δ is equal to or larger than the predetermined dead zone width Wdz in step S54, the processing shown in the following equation (1) is performed in step S56, and the position controller XPI shown in FIG. , YPI, Z
Correction position deviation Δ for PI, XθPI, YθPI, ZθPI
Send c.

Δc = Δ−sgn (Δ) · Wdz Expression (1) Here, when Δ> 0, sgn (Δ) = 1, when Δ <0, sgn (Δ) = − 1

The processing contents shown in FIG. 5A will be described with reference to FIG. 5B by regarding the correction blocks 1000a to 1000f as analog input / output systems. FIG. 5 (b)
In the graph, the horizontal axis represents the positional deviation Δ as an input, and the vertical axis represents the corrected positional deviation Δc as an output. When the dead zone flag is 0, the position controllers XPI, YPI, ZP are set as Δc = Δ as shown by the broken line a.
Correction position deviation Δc for I, XθPI, YθPI, ZθPI
Is output. Conversely, when the dead zone flag is 1, the position controllers XPI, YPI, and IPI have input / output characteristics having a dead zone width Wdz on each of the + side and the-side as shown by the solid line b.
The correction position deviation Δc is output to ZPI, XθPI, YθPI, and ZθPI.

By constructing the vibration control system as described above, a thrust is generated in each actuator only when a high anti-vibration ability is required, so that unnecessary heat generation from each actuator is prevented. be able to.

In the above description, an example is described in which, when the corrected position deviation Δc is obtained from the position deviation Δ, it is determined whether or not the dead zone width of the predetermined width Wdz is taken into account by using the dead zone flag. However, the dead zone flag may not be used. Hereinafter, this example will be described with reference to FIG.

The flowchart shown in FIG.
FIG. 11A shows another example of the position control feedback amount setting routine shown in FIG.
2, that is, dead zone flag determination processing, and step S53,
In other words, except that the processing when the dead zone flag is not set is eliminated, the processing is the same as that of FIG. 5A, and therefore, the description will focus on the differences from FIG. 5A.

In the flowchart shown in FIG. 5A, the dead zone width Wdz is fixed at a predetermined value. However, step S62 in the flowchart shown in FIG.
The dead zone width Wdzv is variable. The dead zone width Wdzv is set according to the processing contents of the projection exposure apparatus by a dead zone width setting routine (not shown) in a processing program incorporated in the control device 11. The dead zone width Wdzv is set to 0 when the processing contents of the projection exposure apparatus need to be performed under the highest anti-vibration ability, and conversely, when a very high anti-vibration ability is not required, Thus, the dead zone width Wdzv is set to an arbitrary value.

The dead zone width Wd set as described above
The results obtained by performing the processing based on the flowchart shown in FIG. 6A according to vz are regarded as correction blocks 1000a to 1000f as analog input / output systems in the same manner as described with reference to FIG. 5B. FIG. 6B shows the relationship between the input and output.
Shown in

In the graph shown in FIG. 6B, when the dead zone width Wdvz is 0, Δc = Δ
It becomes the relationship. This is equal to the dashed line a indicating the input / output relationship between Δc and Δ when the dead zone flag is 0 in the graph shown in FIG. Referring again to FIG. 6B, when the dead zone width Wdzv is relatively narrow Wdzv1, the input / output relationship as indicated by the one-dot chain line b, or when the dead zone width Wdzv is relatively wide Wdvz2, the solid line c. It is shown by the input / output relationship as shown. Then, for example, when there is an input / output relationship as shown by the solid line c, the reaction to the disturbance is suppressed to a certain extent, so that the thrust of each actuator is also reduced, and therefore heat generation from each actuator can be prevented.

The anti-vibration apparatus according to the present invention includes not only an optical exposure apparatus such as a step-and-scan type scanning exposure type projection exposure apparatus and a stepper type projection exposure apparatus, but also a charged particle beam exposure apparatus. It is also applicable to devices.

[0045]

【The invention's effect】

(1) According to the invention described in claim 1 and claim 3,
Even when there is a steady disturbance, thrust is generated in the actuator only when a high anti-vibration capacity is required, so unnecessary heat generation from the actuator is prevented, and a decrease in accuracy due to this heat generation is prevented. be able to. (2) According to the invention described in claim 2 and claim 3,
The dead zone width can be adjusted according to the required level of the vibration isolation capability, and the thrust generated from the actuator can be adjusted as necessary. Therefore, heat generation from the actuator can be more finely suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a projection exposure apparatus according to one embodiment.

FIG. 2A is an enlarged sectional view showing an example of an actuator 7A, and FIG. 2B is an enlarged sectional view showing another example of the actuator 7A.

FIG. 3 is a control block diagram illustrating a configuration of a control system of the actuator.

FIG. 4 is a flowchart illustrating a position control loop dead zone setting routine of the control system shown in FIG. 3;

FIG. 5 is a diagram for explaining an example of a position control loop feedback amount setting routine of the control system shown in FIG. 3;
Is a flow chart, and (b) is a graph schematically showing the feedback amount set by this routine.

6 is a diagram for explaining another example of the position control loop feedback amount setting routine of the control system shown in FIG. 3,
(A) is a flowchart, and (b) is a graph schematically showing a feedback amount set by this routine.

[Explanation of symbols]

4A~4D vibration isolating pads _{5Z 1 ~5Z 3, 5Y 1,} 5Y 2, 5X acceleration sensor (vibration sensor) 6 platen (anti-vibration table) 7A-7D, 32A to 32C actuator 10Z ₁ ~10Z _3, 10Y _1, 10Y ₂ , 10X Displacement sensor 11 Control device (vibration control system) 20 XY stage (substrate stage) 27 Reticle stage 30X, 30Y, 30R Laser interferometer (position measuring means) 40 Exposure main body 100 Exposure device R Reticle (mask) PL Projection optical system W Wafer (photosensitive substrate) 1000a to 1000f Correction block

Claims (3)

[Claims] 1. An anti-vibration table held via a pad, an actuator for driving the anti-vibration table, a displacement sensor for detecting a displacement of the anti-vibration table, and a vibration for detecting vibration of the anti-vibration table A vibration control system that drives and controls each of the actuators so as to suppress displacement and vibration of the vibration isolation table with a sensor, a position control loop based on the output of the displacement sensor, and a speed control loop based on the output of the vibration sensor. And a dead band having a predetermined width that can be selected to be valid or invalid with respect to the output of the displacement sensor is provided in the position control loop. 2. An anti-vibration table held via a pad; an actuator for driving the anti-vibration table; a displacement sensor for detecting a displacement of the anti-vibration table; and a vibration for detecting vibration of the anti-vibration table. A vibration control system that drives and controls each of the actuators so as to suppress displacement and vibration of the vibration isolation table with a sensor, a position control loop based on the output of the displacement sensor, and a speed control loop based on the output of the vibration sensor. And a dead zone for the output of the displacement sensor is provided in the position control loop, and a dead zone width of the dead zone is made variable. 3. An exposure apparatus for transferring a pattern formed on a mask onto a substrate on a substrate stage via a projection optical system, wherein the vibration removing apparatus according to claim 1 or 2 is used to remove an exposure main body. An exposure apparatus comprising a vibration device.