WO2013161858A1

WO2013161858A1 - Controller, stage device, exposure device, and control method

Info

Publication number: WO2013161858A1
Application number: PCT/JP2013/062020
Authority: WO
Inventors: 晃一坂田
Original assignee: 株式会社ニコン
Priority date: 2012-04-24
Filing date: 2013-04-24
Publication date: 2013-10-31
Also published as: TW201351063A

Abstract

A controller is provided with: a control object (P(s)) having a stage on which an object is placed, a first member, and a second member connected to the stage and capable of moving in relation to the first member; a first filter (1-BPF(s)) for feeding back information related to the stage position of the control object in a frequency range that does not include the main resonance frequency in the frequency characteristics of the control object; and a second filter (BPF(s)) for feeding back information related to the position of the second member in a frequency range including the main resonance frequency in the frequency characteristics of the control object.

Description

Control apparatus, stage apparatus, exposure apparatus, and control method

The present invention relates to a control apparatus, a stage apparatus, an exposure apparatus, and a control method.
This application claims priority based on Japanese Patent Application No. 2012-99129 for which it applied on April 24, 2012, and uses the content here.

For example, in an exposure apparatus that exposes a circuit pattern formed on a mask onto a semiconductor substrate, the stage apparatus is used as an important component that is indispensable for positioning the mask and the semiconductor substrate. With the progress of computerization, the demand for the positioning performance is increasing (see, for example, Patent Document 1).

JP 2009-141283 A

FIG. 11 is a block diagram of a P-PI (Proportional-Proportional Integral) control system that controls the position of the stage. In FIG. 11, C _P (s) is a controller that performs proportional control (P control). C _V (s) is a controller that performs proportional / integral control (PI control). D (s) is a differentiator that differentiates the rotation angle θ (t) of the motor and outputs the rotation speed of the motor.
P (s) is a stage that is an object to be controlled. x (t) is the actual measurement position of the stage measured by the laser interferometer. θ (t) is the rotation angle of the motor obtained from the encoder. The stage moves by turning the ball screw with a motor. r (t) is the target position of the stage. e (t) is a difference between the target position r (t) of the stage and the actually measured position x (t). u (t) is the final output from the controller. The sensitivity function S (s) of this P-PI control system is expressed by the following equation (1).

The P-PI control system uses an outer feedback loop that controls C _P (s) so that the difference e (t) between x (t) and r (t) becomes zero using the position x (t). A position outer loop that controls the stage position) and an inner feedback loop (speed minor (inner) loop) in which D (s) controls the speed of motor position differentiation using θ (t). Yes. Originally, the outer loop is mainly used because the position of the stage is desired to be adjusted to a desired position, but a minor loop (inner loop) is used to suppress the influence of disturbance.

FIG. 12 is a block diagram showing a stepper model of the stage device (P (s)). In the figure, θ is a motor position, x is a stage position, and T is a variable representing torque. The transfer function from the torque T to each position is expressed by the following equations (2) to (5).

Where J is the motor inertia, B is the motor viscosity, M is the stage mass, C is the stage viscosity, K is the torsional rigidity of the ball screw, and R is the rotation / translation conversion coefficient of the ball screw.

13A and 13B are conceptual diagrams showing an example of the plant frequency characteristic of the stepper model. FIG. 13A shows the characteristics of the position outer loop (that is, control characteristics related to the stage position), and FIG. 13B shows the characteristics of the speed minor loop (that is, control characteristics related to the rotation angle (motor position)). 13A and 13B, it can be seen that there is a resonance point (main resonance) at about 60 Hz.

In the stage apparatus using the P-PI control system described above, the speed minor loop has no phase change before and after the resonance point (in-phase), but the position outer loop has a phase change before and after the resonance point. Is delayed by about 180 ° (reverse phase). Thus, since the main resonance mode is in-phase with the rigid body, the speed minor loop shown in FIG. 13B can be increased to about 250 Hz at present. On the other hand, at the observation point of the stage position, since the main resonance mode is opposite in phase to the rigid body, the band of the position outer loop shown in FIG. 13A is 10 Hz or less.
Thus, since the control band of the position outer loop cannot be made higher than the resonance frequency, there is a problem that the settling time when the stage is moved becomes long.

An object of an aspect of the present invention is to provide a control device, a stage device, an exposure device, and a control method that can shorten the settling time.

One aspect of the present invention is based on a position outer loop for controlling the control target to be positioned at a target position based on the position of the control target for moving the object, and based on the moving speed of the control target. A control device having a speed inner loop for controlling the object to be controlled to be positioned at the target position, wherein the control object is connected to the stage, the first member, and the stage. A control member having a second member movable relative to the member, and information relating to the position of the stage of the control object in a frequency range that does not include a main resonance frequency in the frequency characteristics of the control object. The first filter to be fed back and the information on the position of the second member are fed in the frequency range including the main resonance frequency in the frequency characteristic of the controlled object. A second filter for click, which is a control device, characterized in that it comprises a.

In the above aspect, the second filter has a band-pass filter characteristic BPF (s) that passes a frequency range around the main resonance frequency, and the first filter is centered on the main resonance frequency. It is possible to have a band stop filter characteristic (1-BPF (s)) that allows passage of frequencies other than those before and after.

In the above aspect, the first filter has a low-pass filter characteristic LPF (s) that passes a low frequency range lower than the main resonance frequency, and the second filter passes a high frequency range higher than the main resonance frequency. It can have a high-pass filter characteristic (1-LPF (s)).

In the above aspect, the first filter combines a low-pass filter characteristic LPF (s) that passes a low frequency range lower than the main resonance frequency and a notch filter (NF (s)) that blocks a predetermined frequency range. The second filter has a high-pass filter characteristic (1-LPF (s)) that passes a high frequency range higher than the main resonance frequency, and the predetermined filter characteristic (LPF (s) · NF (s)). Filter characteristics ((1-LPF (s)) · NF (s)) combined with a notch filter (NF (s)) that blocks the frequency range of.

According to another aspect of the present invention, there is provided a stage that is movable in a predetermined direction with respect to the base and elastically coupled to the base, a drive unit that moves the stage along the predetermined direction, and the stage. And a control device for controlling the driving means so as to position and stop the motor at the target position, the control device positioning the stage at the target position based on the position of the stage. A position outer loop to be controlled, a speed inner loop for controlling the stage to be positioned at a target position based on a moving speed of the stage, and a frequency range not including a main resonance frequency in the frequency characteristic of the stage, A first filter that feeds back information on the position of the stage, and a main frequency characteristic of the stage; In the frequency range including a resonant frequency, a stage apparatus characterized by comprising a second filter for feedback information on the movement speed of the stage.

According to another aspect of the present invention, there is provided an exposure apparatus that exposes a mask pattern held on a mask stage onto a photosensitive substrate held on a substrate stage, wherein at least one of the mask stage and the substrate stage is provided. A position outer loop that is controlled so as to be positioned at a target position based on the position of the stage, and a speed that is controlled so that the at least one stage is positioned at the target position based on a moving speed of the stage. An inner loop, a first filter that feeds back information on the position of the stage in a frequency range that does not include a main resonance frequency in the frequency characteristics of the stage, and a frequency range that includes a main resonance frequency in the frequency characteristics of the stage, Provide feedback on stage movement speed An exposure apparatus, characterized in that it comprises a control device and a second filter.

According to another aspect of the present invention, a position outer loop for controlling the control target to be positioned at a target position based on a position of the control target for moving the object, and a moving speed of the control target And a speed inner loop for controlling the control target to be positioned at the target position based on the stage, the stage on which the object is placed, a first member, and connected to the stage, Feeding back information on the position of the stage of the controlled object in a frequency range that does not include a main resonance frequency in the frequency characteristics of the controlled object having a second member movable relative to the first member. And information regarding the position of the second member of the controlled object in a frequency range including a main resonance frequency in the frequency characteristics of the controlled object. A control method characterized by comprising the steps of back, the.

According to the aspect of the present invention, the control device can shorten the settling time.

FIG. 3 is a block diagram of a frequency separation P-PI (FSP-PI) control system for performing stage position control according to an embodiment of the present invention. It is a conceptual diagram which shows the filter characteristic for demonstrating the setting method of the characteristic of a 1st filter and a 2nd filter by this embodiment. It is a conceptual diagram which shows the filter characteristic for demonstrating the setting method of the characteristic of a 1st filter and a 2nd filter by this embodiment. It is a conceptual diagram which shows the filter characteristic for demonstrating the setting method of the characteristic of a 1st filter and a 2nd filter by this embodiment. It is a top view which shows the structure of the stage apparatus by one Embodiment of this invention. It is a side view (only an upper part is shown from a Y stage) of the stage device for explaining detailed position control of the X stage in a stage device. It is a side view which shows the structure of the exposure apparatus to which the stage apparatus by this embodiment is applied. It is a perspective view which shows the structure of the other stage apparatus by one Embodiment of this invention. It is a side view for demonstrating the detailed position control of the X stage of the other stage apparatus by one Embodiment of this invention. It is a side view which shows schematic structure of the projection exposure apparatus using a stage apparatus. It is a conceptual diagram which shows the comparison result of the frequency sensitivity characteristic of the FSP-PI control system by this embodiment, and the P-PI control system by a prior art, and a Nyquist diagram. It is a conceptual diagram which shows the comparison result of the frequency sensitivity characteristic of the FSP-PI control system by this embodiment, and the P-PI control system by a prior art, and a Nyquist diagram. It is a conceptual diagram which shows a position error response result as actual machine verification of the stage apparatus using the FSP-PI control system by this embodiment. It is a block diagram of a P-PI control system for performing stage position control. It is a block diagram which shows the stepper model of a stage apparatus (P (s)). It is a conceptual diagram which shows an example of the plant frequency characteristic of the said stepper model. It is a conceptual diagram which shows an example of the plant frequency characteristic of the said stepper model.

In the embodiment of the present invention, the frequency separation is performed by a filter so that the motor position is fed back in the middle region where the main resonance exists, and the stage position is fed back in the low region related to positioning and the high region which is easily affected by the resolution. The control system according to the embodiment of the present invention is referred to as a frequency separation P-PI (FSP-PI; Frequency Separation P-PI).

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a frequency separation P-PI (FSP-PI) control system of a control apparatus that performs stage position control according to an embodiment of the present invention. In addition, the same code | symbol is attached to the part corresponding to FIG. 11, and description is abbreviate | omitted.
As shown in FIG. 1, the FSP-PI control system of this embodiment includes a bandpass filter (BPF (s)) and a filter (1-BPF (1) in addition to the components of the P-PI control system shown in FIG. s)) and a multiplier (R).
The bandpass filter (BPF (s)) is a filter having a characteristic that allows a frequency component in the vicinity of the resonance frequency to pass. On the other hand, the filter (1-BPF (s)) is a filter having a characteristic of passing a frequency component other than the frequency region in the vicinity of the resonance frequency.

The band-pass filter (BPF (s)) feeds back the position of the stage based on the rotation angle of the motor in the frequency range near the resonance frequency. The multiplier (R) converts the rotation angle of the motor into the position of the stage. The filter (1-BPF (s)) feeds back the stage position at a position away from the resonance frequency, that is, outside the frequency region in the vicinity of the resonance frequency.
Hereinafter, the bandpass filter (1-BPF (s)) is referred to as a first filter, and the bandpass filter (BPF (s)) is referred to as a second filter.

The sensitivity function of this control system is expressed by the following equation (6).

Here, BPF (s) is composed of a primary HPF (High Pass Filter) and a primary LPF (Low Pass Filter), and is represented by the following equation (7).

However, it is assumed that f _HPF <f _LPF .
In the P-PI control system shown in FIG. 11, as shown in FIGS. 13A and 13B, the main resonance is 60 Hz and exists in the middle range. Therefore, in the FSP-PI control system of this embodiment, for example, if the resonance frequency of the primary HPF is f _HPF = 10 Hz and the resonance frequency of the primary LPF is f _LPF = 1 kHz, the frequency is separated before and after the main resonance. be able to.

Next, a method for setting the characteristics of the first filter and the second filter will be specifically described.
2A to 2C are conceptual diagrams showing filter characteristics for explaining a method for setting the characteristics of the first filter and the second filter according to the present embodiment. Here, when the characteristic of the first filter is A (s) and the characteristic of the second filter is B (s), A (s) and B (s) are set so as to satisfy the following two conditions. .

(Condition 1) A (s) has such a characteristic that the output of the second filter is more dominant than the output of the first filter at a frequency near the resonance frequency.

(Condition 2) A (s) + B (s) = 1

Next, specific setting patterns of the first filter and the second filter are shown.
(First pattern)
B (s) is a characteristic represented by the above mathematical formula (7).
A (s) is 1-BPF (s).
In addition, BPF (s) represented by the above formula (7) is as shown in FIG. 2A.
Since A (s) is a vertically inverted BPF (s), the output of the first filter is suppressed near the resonance frequency, and the output of the second filter becomes dominant. Note that the above-described primary HPF refers to the first term of Equation (7) of BPF (s), and the primary LPF refers to the second term of Equation (7). However, higher order HPF and LPF may be used instead of the first order.

(Second pattern)
A (s) is LPF (s) shown in Equation (7) (that is, the second term of Equation (7)).
Let B (s) be 1-LPF (s).
LPF (s) is as shown in FIG. 2B.

(Third pattern)
A (s) is LPF (s) · NF (s) (the product of the LPF of the second pattern and the notch filter NF).
B (s) is 1-LPF (s) · NF (s). The notch filter NF (s) has characteristics as shown in FIG. 2C.

It may be difficult to sufficiently reduce the gain of A (s) at the resonance frequency only with the second pattern LPF. In the third pattern, since the gain of A (s) at the resonance frequency is further reduced at the valley of the notch filter NF, the output of the first filter can be suppressed near the resonance frequency compared to the second pattern.

Next, the stage apparatus using the frequency separation P-PI (FSP-PI) control system according to the present embodiment will be described.
FIG. 3 is a top view showing a configuration of a stage apparatus 100 using a frequency separation P-PI (FSP-PI) control system according to an embodiment of the present invention. A Y stage 2 is provided on the upper surface of the base 1 via a predetermined support mechanism (not shown) such as a bearing so as to be movable in the Y direction (up and down direction in the figure). An X stage 3 is provided above the Y stage 2 through a similar support mechanism (not shown) so as to be movable in the X direction (left and right in the figure).

The Y stage 2 has a nut portion at a part thereof, and a Y ball screw 21 penetrates the nut portion to engage with each other. When the Y motor 22 provided on the base 1 rotates the Y ball screw 21, thrust in the Y direction is generated in the Y stage 2 via the nut portion, and the Y stage 2 moves in the Y direction with respect to the base 1. It is configured to move.
A command value for instructing the rotational torque of the Y ball screw 21 is input to the Y motor 22 in order to move the Y stage 2 to the target position, and the Y ball screw 21 is rotated in accordance with the command value. Positioned to position.

Furthermore, in order to control to attenuate the vibration generated when the Y stage 2 is positioned, the following damping mechanism using a linear motor is provided.
That is, two rows of Y

linear motor stators

23A and 23B are linearly provided along the Y direction on the base 1. Y linear motor movable elements 24A and 24B (not shown) are provided on the Y stage 2 at portions facing the Y

linear motor stators

23A and 23B. The Y

linear motor stators

23A and 23B and the Y linear motor movers 24A and 24B generate an electromagnetic force therebetween to attenuate the vibration of the Y stage 2.

At this time, the position of the Y stage 2 with respect to the base 1 using a laser interferometer that irradiates the laser beams L to the corner cubes CCY1 and CCY2 fixed to the Y stage 2 via the half mirror HM and the mirror MR to cause interference. Measure. Then, the electromagnetic force of the linear motor (Y linear motor) is controlled so that the vibration is attenuated based on the measurement position.
A plurality of linear motors that generate driving force in the same direction (here, the Y direction) may be provided. A plurality of interferometers that measure the position of the Y stage 2 with respect to the base 1 may be provided. When a plurality of linear motors are provided, the linear motor and the interferometer can be provided so as to correspond to each other. Further, the linear motor and the interferometer may be arranged at adjacent positions in a state where they correspond to each other.

The position control of the X stage 3 is the same as the position control of the Y stage 2 described above.
That is, the X stage 3 has a nut portion (not shown) in a part thereof, and the X ball screw 31 penetrates the nut portion to engage with each other. When the X motor 32 provided on the Y stage 2 rotates the X ball screw 31, thrust in the X direction is generated in the X stage 3 via the nut portion, and the X stage 3 is X with respect to the Y stage 2. It is configured to move in the direction.
A command value for instructing the rotational torque of the X ball screw 31 is input to the X motor 32 in order to move the X stage 3 to the target position, and the X ball screw 31 is rotated in accordance with the command value. Positioned to position.

Further, in order to control to attenuate the vibration generated when the X stage 3 is positioned, the following damping mechanism using a linear motor is provided.
That is, the Y stage 2 is provided with two rows of X

linear motor stators

33A and 33B linearly along the X direction. X linear motor movable elements 34A and 34B (not shown) are provided on the X stage 3 at portions facing the X

linear motor stators

33A and 33B. The X

linear motor stators

33A and 33B and the X linear motor movable elements 34A and 34B generate an electromagnetic force therebetween to attenuate the vibration of the X stage 3.

At this time, the laser beam L is irradiated to the corner cubes CCX1 and CCX2 fixed to the X stage 3 via the half mirror HM and the mirror MR to cause interference, thereby causing the X stage 3 to move with respect to the Y stage 2. Measure the position. Then, the electromagnetic force of the linear motor (X linear motor) is controlled so that the vibration is attenuated based on the measurement position.

A plurality of linear motors that generate driving force in the same direction (here, the X direction) may be provided. A plurality of interferometers that measure the position of the X stage 3 relative to the Y stage 2 may be provided. When a plurality of linear motors are provided, the linear motor and the interferometer can be provided so as to correspond to each other. Further, the linear motor and the interferometer may be arranged at adjacent positions in a state where they correspond to each other.

FIG. 4 is a side view of the stage apparatus 100 for explaining detailed position control of the X stage 3 in the stage apparatus 100 (only the upper part from the Y stage 2 is shown).
The stage apparatus 100 uses two laser interferometers, a positioning interferometer and an interferometer for the linear motor (X linear motor), in order to measure the position of the X stage 3. The positioning interferometer measures the position Px of the X stage 3 using the positioning interferometer measurement unit 36 provided outside the X stage 3 and the Y stage 2 with reference to the installation position of the positioning interferometer measurement unit 36. To do.

For example, the positioning interferometer measuring unit 36 can be installed on a metrology frame (not shown) or the base 1 provided outside the base 1. Further, when the stage apparatus 100 is applied to the exposure apparatus shown in FIG. 5 described later, for example, the stage apparatus 100 can be installed in an illumination optical system 202 of the exposure apparatus. In these cases, the measurement position Px is the position of the X stage 3 measured with reference to the base 1 and the illumination optical system 202.

In general, the stage apparatus performs position control of the X stage 3 according to the measurement position Px measured by such a positioning interferometer.
Specifically, the rotational torque of the X ball screw 31 necessary to move the X stage 3 to the target position is calculated based on the measurement position Px. The calculated rotational torque command value is given to the X motor 32 as a motor control value. The X motor 32 rotates the X ball screw 31 in accordance with the motor control value, whereby the position of the X stage 3 is controlled to the target position.

FIG. 5 is a side view showing a configuration of an exposure apparatus 201 to which the stage apparatus 100 according to the present embodiment is applied. The exposure apparatus 201 includes an illumination optical system 202, a mask stage apparatus 203 that moves while holding a mask M (object), a projection optical system PL, and a substrate stage apparatus 205 that moves while holding a glass substrate P. Consists of including.

The illumination optical system 202 includes a light source unit, a shutter, a secondary light source forming optical system, a beam splitter, a condensing lens system, a reticle blind, and an imaging lens system, all not shown. The illumination optical system 202 illuminates a predetermined illumination area (including a circuit pattern) on the mask M held by the mask stage device 203 with uniform illumination by the illumination light IL.

The projection optical system PL is an optical system (for example, a refractive optical system) having a plurality of lens elements arranged at predetermined intervals along the optical axis AX direction. When the illumination area of the mask M is illuminated by the illumination light IL from the illumination optical system 202, the predetermined magnification of the circuit pattern of the illumination area on the mask M via the projection optical system PL by the illumination light that has passed through the mask M Are projected onto the glass substrate P, whereby the photoresist applied to the surface of the glass substrate P is exposed.

1 is used as at least one of the mask stage device 203 and the substrate stage device 205. Here, when used as the mask stage device 203, the mask M is held by the plate holder on the X stage 3. When used as the substrate stage device 205, the glass substrate P is held by the same plate holder.

FIG. 6 is a perspective view showing the configuration of another stage apparatus according to an embodiment of the present invention.
In FIG. 6, a stage apparatus 300 is configured such that a stage apparatus that can move in the X direction and a stage apparatus that can move in the Y direction are combined, and the table can move freely in a horizontal plane. The table has an X table 37X movable in the X direction and a Y table 37Y movable in the Y direction.
The X table 37X is provided on the Y table 37Y. The X table 37X is supported on the Y table 37Y by a non-contact type guide mechanism (air bearing or the like) 36X extending in the X direction. Further, the Y table 37Y that supports the X table 37X is provided on the vibration isolation table 303. The Y table 37Y is supported on the vibration isolation table 303 by a non-contact type guide mechanism (air bearing or the like) 36Y extending in the Y direction.

The Y table 37Y is driven in the Y direction by a feed screw 35Y provided in parallel with the guide mechanism 36Y. The feed screw 35Y is driven by a motor 34Y attached on the vibration isolator 303.

Linear motor mechanisms

322Y and 323Y are provided between the Y table 37Y and the vibration isolation table 303.
The X table 37X is driven in the X direction by a feed screw 35X provided in parallel with the guide mechanism 36X. The feed screw 35X is driven by a motor 34X attached on the Y table 37Y.

Linear motor mechanisms

322X and 323X are provided between the X table 37X and the Y table 37Y.

The laser interferometer 312Y is configured to detect the position of the Y table 37Y with high accuracy. Specifically, the laser interferometer 312Y irradiates the reflecting mirror 313Y provided on the X table 37X with laser light, and measures the position of the Y table 37Y in a non-contact manner based on the return light.
The laser interferometer 312X is configured to detect the position of the X table 37X with high accuracy. Similarly to the laser interferometer 312Y, the laser interferometer 312X irradiates the reflecting mirror 313X provided on the X table 37X with laser light, and measures the position of the X table 37X in a non-contact manner based on the return light.
In FIG. 6, although simplified, the laser interferometer 312Y is fixed on the anti-vibration table 303, and the laser interferometer 312X is fixed on the Y table 37Y.

Here, paying attention to the fact that the basic configurations of the

linear motor mechanisms

322X and 323X for driving the X table 37X in the X direction and the

linear motor mechanisms

322Y and 323Y for driving the Y table 37Y in the Y direction match, FIG. The

linear motor mechanisms

322X and 323X that drive the X table 37X in the X direction will be described.
The

linear motor mechanisms

322X and 323X provided between the X table 37X and the Y table 37Y are the linear motor mechanism 322X (stator) attached to the X table 37X side of the Y table 37Y, and the X table 37X. The linear motor mechanism 323X (movable element) is attached to the Y table 37Y side.
Similarly, in the Y direction,

linear motor mechanisms

322Y and 323Y are provided between the Y table 37Y and the vibration isolation table 303 (see FIG. 8).

The stage apparatus 300 further includes a control unit 324. The control unit 324 receives the table position information measured by the

laser interferometers

312X and 312Y in cooperation with the reflecting

mirrors

313X and 313Y, and receives the

motor

34X and 34Y and the feed screws 35X and 35Y or the linear motor mechanism 322X, The X table 37X and the Y table 37Y are appropriately driven through 323X and 322Y and 323Y. In addition to these, the control unit 324 controls the entire apparatus.

In the above configuration, when the stage apparatus 300 according to this embodiment is used in a projection exposure apparatus 400 (described later) for manufacturing a semiconductor, a table (Y table 37Y) on which a wafer W (object) as a photosensitive substrate is placed. The X table 37X) is driven so that the next exposure area after the projection exposure is positioned at a predetermined position in the projection field of the projection optical system.

FIG. 8 is a side view showing a schematic configuration of a projection exposure apparatus 400 using the stage apparatus 300.
In the stage apparatus 300 used in the projection exposure apparatus 400 for manufacturing a semiconductor, a stage controller (not shown) drives a motor (34X) 34Y provided on a vibration isolating base 303 that constitutes a base. A table (37X) 37Y guided by a guide mechanism (36X) 36Y is driven to a predetermined position via a feed screw (drive shaft) (35X) 35Y.
A wafer W, which is a photosensitive substrate, is placed on the table (37X) 37Y, and light emitted from a light source 408 in a desired exposure area on the wafer surface is constituted by a lens system such as a fly-eye lens and a condenser lens. The aperture is narrowed down through the illumination optical system 409, the reticle 410, and the projection lens 411, and the mask pattern is imaged on the wafer W.
After the projection exposure of the exposure area is completed, the table (37X) 37Y is appropriately driven so that the next exposure area is positioned at a predetermined position within the projection field of the projection lens 411. The laser interferometer (312X) 312Y measures the position of the table (37X) 37Y based on the reflected light from the movable mirror 313Y provided on the table (37X) 37Y.

In the stage apparatus 300 in the projection exposure apparatus 400, the entire apparatus excluding the table (37X) 37Y is fixed as a rigid body on the vibration isolator 303, and the table (37X) 37Y includes a feed screw (35X) 35Y and a table (37X) 37Y. The guide mechanism (36X) 36Y is substantially fixed as a rigid body to the apparatus main body.
In other words, the table (37X) 37Y and the apparatus are integrated on a macro scale, but the table (37X) 37Y is the basis on a micro scale when comparing the rigidity of the entire apparatus and the support rigidity of the table (37X) 37Y. It is equivalent to a structural model that is spring-supported above. This is because the lead screw (35X) 35Y is not regarded as a complete rigid body due to play and friction of the joint in the accuracy required here.
Linear motor mechanisms 422 and 423 serve as second drive means for moving the table (37X) 37Y in the direction along the feed screw (35X) 35Y between the table (37X) 37Y and the vibration isolation table 303. Has been placed.

The above-described stage apparatus shown in FIGS. 3 and 4 or the stage apparatus shown in FIGS. 6 and 7 is represented as the model shown in FIG.

9A and 9B are conceptual diagrams showing comparison results of frequency sensitivity characteristics and Nyquist diagrams between the FSP-PI control system according to the present embodiment and the P-PI control system according to the prior art. 9A is a proportional gain _{K p} of the position the outer loop shows the case of a 40. 9B is a proportional gain _{K p} of the position the outer loop shows the case of a 80.
In the Nyquist diagrams shown in FIGS. 9A and 9B, the distance between the point (−1, 0) and each point on the curve (P-PI or FSP-PI) is the inverse of the sensitivity function 1 / | S (s) | Is equal to Also, the smaller the value of the sensitivity function S (s), the better the control characteristics against disturbance. Therefore, the further away the curve from the point (−1, 0) on the Nyquist diagram, the better the control characteristics.

If the proportional gain K _p of the position outer loop doubled, as shown in FIG. 9B, the curve of P-PI control system to a circle of radius 0.5 centered at point (-1, 0) in the Nyquist diagram There is little stability margin. This is because the phase is delayed due to the influence of the main resonance. On the other hand, the FSP-PI control system mainly uses the motor position information by BPF in the middle region where the main resonance exists. For this reason, the phase is recovered in the FSP-PI control system compared to the P-PI control system. This can be read from the Nyquist diagram.
As a result, it can be seen that a control system with a sufficient stability margin can be realized even if the gain is doubled. That is, according to the Nyquist diagrams shown in FIGS. 9A and 9B, the FSP-PI control system shows a characteristic curve away from the point (−1, 0), so that the control characteristics are improved. .

FIG. 10 is a conceptual diagram showing a position error response result as actual machine verification of the stage apparatus using the FSP-PI control system according to the present embodiment. However, a nonlinear gain map is used. In FIG. 10, in the upper graph, the horizontal axis is defined as time, and the vertical axis is defined as position error. In the lower graph, the horizontal axis is defined as time, and the vertical axis is defined as accelerating movement, constant speed movement, decelerating movement, exposure, and settling in order from the bottom.
In the conventional P-PI control system, the settling time is about 200 ms. On the other hand, in the FSP-PI control system according to the present embodiment, the settling time is shortened to about 100 ms. Since the settling time varies depending on the stage coordinate position and each step, the settling time needs to be measured a plurality of times, but the settling time can be sufficiently shortened.

1 ... base 2 ... Y stage 3 ... X stage 21 ... Y ball screw 22 ...

Y motor

23A, 23B ... Y linear motor stator 24A, 24B ... Y linear motor mover 31 ... X ball screw 32 ...

X motor

33A, 33B ... X linear motor stator 34A, 34B ... X linear motor

movable element

34X, 34Y ...

motor

35X, 35Y ... feed screw 36 ... positioning

interferometer measuring section

36X, 36Y ... guide mechanism 37X ... X table 37Y ... Y table 37 ... Encoder 38 ... Nut part 201 ... Exposure apparatus 202 ... Illumination optical system 203 ... Mask stage apparatus 205 ... Substrate stage apparatus 300 ... Stage apparatus 303 ... Anti-vibration table 312X, 312Y ...

Laser interferometers

313X, 313Y ...

Reflector

322X, 322Y ... Re Amota mechanism (stator) 323x, 323Y ... linear motor mechanism (movable element) 324 ... control unit 400 ... projection exposure apparatus 408 ... light source 409 ... illumination optical system.

Claims

A position outer loop for controlling the control target to be positioned at the target position based on the position of the control target for moving the object, and the control target based on the moving speed of the control target. A control device having a speed inner loop for controlling to be positioned at a position,
The control object having a stage on which the object is placed, a first member, and a second member connected to the stage and movable with respect to the first member;
A first filter that feeds back information related to the position of the stage of the control object in a frequency range that does not include a main resonance frequency in the frequency characteristics of the control object;
A second filter that feeds back information related to the position of the second member in a frequency range including a main resonance frequency in the frequency characteristics of the controlled object;
A control device comprising:
The second filter has a bandpass filter characteristic BPF (s) that allows a frequency range around the main resonance frequency to pass through,
2. The control device according to claim 1, wherein the first filter has a band stop filter characteristic (1 -BPF (s)) that allows passage of frequencies other than the front and rear frequency ranges centered on the main resonance frequency.
The first filter has a low-pass filter characteristic LPF (s) that passes a low frequency region lower than the main resonance frequency,
The control device according to claim 1, wherein the second filter has a high-pass filter characteristic (1-LPF (s)) that passes a high frequency region higher than the main resonance frequency.
The first filter has a filter characteristic (LPF) that combines a low-pass filter characteristic LPF (s) that passes a low frequency range lower than the main resonance frequency and a notch filter (NF (s)) that blocks a predetermined frequency range. (S) · NF (s))
The second filter combines a high-pass filter characteristic (1-LPF (s)) that passes a high frequency range higher than the main resonance frequency and a notch filter (NF (s)) that blocks the predetermined frequency range. The control device according to claim 1, further comprising: a filter characteristic ((1-LPF (s)) · NF (s)).
A stage that is movable in a predetermined direction with respect to the base and is elastically coupled to the base, a driving unit that moves the stage along the predetermined direction, and the stage is positioned at a target position and stopped. A stage device comprising a control device for controlling the driving means,
The control device includes:
A position outer loop for controlling the stage to be positioned at a target position based on the position of the stage;
A speed inner loop for controlling the stage to be positioned at a target position based on the moving speed of the stage;
A first filter that feeds back information related to the position of the stage in a frequency range that does not include a main resonance frequency in the frequency characteristics of the stage;
A stage device comprising: a second filter that feeds back information related to the moving speed of the stage in a frequency range including a main resonance frequency in the frequency characteristics of the stage.
In an exposure apparatus that exposes a mask pattern held on a mask stage onto a photosensitive substrate held on a substrate stage,
A position outer loop for controlling at least one of the mask stage and the substrate stage to be positioned at a target position based on the position of the stage; and
A speed inner loop that controls the at least one stage to be positioned at the target position based on a moving speed of the stage;
A first filter that feeds back information related to the position of the stage in a frequency range that does not include a main resonance frequency in the frequency characteristics of the stage;
An exposure apparatus comprising: a control device including: a second filter that feeds back information related to a moving speed of the stage in a frequency range including a main resonance frequency in the frequency characteristics of the stage.
A position outer loop for controlling the control target to be positioned at the target position based on the position of the control target for moving the object, and the control target based on the moving speed of the control target. A control method having a speed inner loop for controlling to be positioned at a position,
Including a main resonance frequency in a frequency characteristic of the controlled object, comprising: a stage on which the object is placed; a first member; and a second member connected to the stage and movable with respect to the first member. Feeding back information on the position of the stage of the controlled object in a non-frequency region;
Feeding back information on the position of the second member of the control object in a frequency range including a main resonance frequency in the frequency characteristics of the control object;
The control method characterized by including.