JPH08241848A - Stage positioning control device - Google Patents

Abstract

PURPOSE: To enhance a stage positioning control device in positioning performance, wherein the stage positioning control device is composed of a coarse- adjustment stage which is positioned in a horizontal plane and a fine-adjustment stage which is mounted on the coarse adjustment stage and controlled in position in a vertical direction and an angle of inclination wit,h a vertical axis. CONSTITUTION: A stage positioning control device is composed of an X-Y stage 19 which is positioned in a horizontal plane, a fine-adjustment stage 9 where actuators 10M, 10R, and 10L are arranged, X-Y stage control devices 21 to 29, and a fine-adjustment stage control device 100. A switch means 30 which detects step drive signals in the X-Y stage control devices and selects them only while step driving is carried out and a feed forward compensator 31 which subjects the signals selected by the switch means 30 to suitable frequency shaping are provided, and the signals outputted from the feed forward compensator 31 are fed forward to the fine adjustment stage control device 100 taking a motion mode into consideration only while the X-Y stage is step-driven.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stage positioning control device having a fine movement stage for fine positioning on an XY stage for coarse movement, and more particularly to a stage positioning control device having improved positioning characteristics. .

[0002]

2. Description of the Related Art In a semiconductor exposure apparatus typified by a stepper, a passive vibration isolator or an active vibration isolator has
The mechanism is such that an XY stage for coarse movement is mounted and a fine movement stage for fine positioning is further mounted thereon. For example, as shown in FIG. 3, an XY stage and a fine movement stage are mounted on a surface plate 8 that is vibration-supported by a passive vibration isolation device or an active vibration isolation device (not shown). In FIG. 3, 1 is an X stage, 2 is a fine movement stage for finely positioning the silicon wafer 3 mounted on the X stage 1,
4 is a Y stage, 5R and 5L are movers of a linear motor that drives the Y stage 4, 6R and 6L are coils that are stators of the linear motor, 7 is a stage surface plate, and 8 is supported by a vibration isolation device (not shown). The surface plate to be used is shown.

Next, the fine movement stage 2 and a device for positioning it will be specifically described. FIG. 4 is a block diagram of a fine movement stage control device for performing positioning control of a total of 3 degrees of freedom including 1 translational degree of freedom in the vertical direction and 2 degrees of rotation in the horizontal plane. The configuration of this fine movement stage control device is proposed in Japanese Patent Application No. 6-132405 filed by the present applicant, and is characterized in that the motion modes of translation and rotation can be controlled without interference. In FIG. 4, 9 is a flat plate-shaped substrate for positioning, and 10M, 10R, and 10L are actuators that generate displacement in the vertical direction. For example, this includes a displacement magnifying mechanism using a piezoelectric element (piezo element) as a driving element. Further, in the vicinity of the driving point by the actuators 10M, 10R, 10L, a position sensor 1 for measuring the displacement of the substrate 9 in the vertical direction (z axis).
There are 1M, 11R, and 11L, and these are called drive stages.

Now, the position sensors 11M, 11R, 11L
The vertical displacement of the substrate 9 measured by the electric signals z _M and z by the displacement amplifiers 12M, 12R and 12L.
Converted to _R , z _L. This electric signal is guided to the motion mode extraction circuit 17 and the motion mode displacement signals (z _g , z θ
_x , zθ _y ), each of which is the command voltage input terminal 13
M, 13R, is compared to the voltage applied to 13L with motion mode error signal _{(e g, eθ x, eθ} y) becomes. These motion mode deviation signals are input to deviation amplifiers 14M, 14R and 14L so as to obtain a predetermined sensitivity, and are introduced to gain compensators 15M, 15R and 15L that adjust the control loop. The motion mode control signals (c
_g , cθ _x , cθ _y ) with the motion mode distribution circuit 18
Input to and output from each axis (d _M , d _R , d _L )
Generate Finally, drive signals (d _M , d _R ,
The power amplifiers 16M, 16R, 16L are excited by d _L ), and the vertical movement of the actuators 10M, 10R, 10L causes the substrate 9 to be translated in the vertical direction or tilted with respect to the z-axis. These closed loops are referred to as a feedback device, and here, the fine movement stage and the feedback device described above are referred to as a fine movement stage control device. In the above description,
The power amplifiers 16M, 16R, 16L are of a type that outputs a current in response to a voltage input. At this time, the gain compensators 15M, 15R, and 15L may be compensators capable of only gain adjustment. Actuator 10M,
This is because the piezoelectric elements constituting 10R and 10L are capacitors when viewed electrically, and the transfer function including the power amplifiers 16M, 16R and 16L and the piezoelectric elements driven by them has integral characteristics. Therefore, when the closed loop is configured, the control system is of type 1, and according to the teaching of the control theory, the steady deviation of zero is guaranteed for the step input.

[0005]

By the way, the positioning mechanism shown in FIG. 3, that is, a passive vibration isolation device or an active vibration isolation device (not shown), and the X stage 1 which plays the role of coarse movement.
The final purpose of the positioning mechanism including the XY stage including the Y stage 4 and the fine movement stage 2 is to position the silicon wafer 3 on the fine movement stage 2 and expose it. Therefore, the above three types of positioning mechanisms are kinematically coupled and moved.

However, in the positioning mechanism shown in FIG. 3, when the positioning performance of the fine movement stage is pursued, the mechanical interference with the XY stage becomes remarkable, so that the total positioning including the XY stage and the fine movement stage is performed. There was a problem that performance could not be improved. For example,
It is possible to set the gain in the fine movement stage control device to the maximum within the stable range so that the fine movement stage itself exhibits the best positioning performance. However, when an XY stage equipped with such a fine movement stage is subjected to acceleration / deceleration driving, torque disturbance acts on the fine movement stage due to step driving in the x-axis and y-axis directions, respectively, and the total movement of the XY stage and the fine movement stage is increased. The positioning stability was significantly impaired.

The present invention has been made in view of the problems in the above-mentioned conventional example, and a fine movement stage for controlling the position in the vertical direction and the inclination from the vertical axis is mounted on a coarse movement stage for positioning in a horizontal plane. It is an object of the present invention to improve the positioning performance of the stage positioning control device.

[0008]

In order to solve the above-mentioned problems, in the present invention, appropriate compensation is applied to the signal for step-driving the XY stage, and this compensation signal is fed into the fine movement stage controller. It is configured to feed forward in consideration of the motion mode. More specifically, an XY stage for positioning in a horizontal plane mounted on a surface plate, which is a vibration isolation device installed on the floor surface, and a vertical axis direction and a vertical axis from the XY stage mounted on the XY stage. A positioning device comprising a fine movement stage in which an actuator is arranged to control the tilt, the XY stage control device for positioning the XY stage, a fine movement stage control device for positioning the fine movement stage, The stepping drive signal for positioning the XY stage is provided with means for feeding forward a compensation signal, which is frequency-shaped according to a motion mode, to the fine movement stage controller for the stepping drive period of the XY stage. And In a preferred embodiment of the present invention, the means for feeding forward is the XY
Switch means for detecting a step drive signal in the stage control device and selecting the drive signal only during a step drive period, and a feedforward compensator for performing appropriate frequency shaping on the signal selected by the switch means. And the feedforward compensator is configured to feedforward the output signal to the fine movement stage control device in consideration of the motion mode only during the step driving of the XY stage.

[0009]

In the conventional positioning mechanism shown in FIGS. 3 and 4, a passive or active vibration isolation device (not shown),
XY stage that plays the role of coarse movement, and 3 of fine movement stage 2
A type of positioning mechanism will be kinematically coupled and moved to position the silicon wafer 3 on the fine movement stage 2. However, in the conventional positioning mechanism, the control device for the XY stage having the degree of freedom of movement in the horizontal direction and the actuators 10M, 10R, 10 are used.
There was no relation that the control device for the fine movement stage, which was given a degree of freedom of driving in the vertical axis direction by using L, was connected to each other by some control loop. Rather,
No relationship between such control loops was allowed,
It might be better to say Since the XY stage whose main purpose is rough positioning in the horizontal direction and the fine movement stage for bringing the surface of the silicon wafer 3 into the best focus state have different degrees of freedom in positioning,
It was quite natural that the control devices for both stages were configured independently.

However, even if the control devices are independent of each other, the XY stage and the fine movement stage have mechanical interference, which is a cause of hindering the improvement of the overall positioning characteristics including both stages. The facts should not be overlooked. That is, it should be noted that the fine movement stage becomes a vibration load for the positioning of the XY stage.
The step drive of the XY stage causes disturbance to act on the fine movement stage, causing it to vibrate.

In the present invention, the XY stage control device and the fine movement stage control device, which have different degrees of freedom for controlling each other, are controllably associated with each other by a feedforward path from the former control device to the latter. And
It is intended to improve the overall positioning performance including the fine movement stage and the XY stage. Specifically, XY
Vibration is generated in the fine movement stage by the step drive of the stage, which causes deterioration of the positioning characteristics including the positioning time and the positioning accuracy. Therefore, the feedforward compensation signal synchronized with the step drive of the XY stage is used for free movement. The present invention has devised to input to the fine movement stage control device in consideration of the degree.

It is common that feedforward is applied to a device that controls the speed and positioning of two or more driven objects if the driving directions of the driven objects are the same. . For example, JP-A-6-2160
3, in a mechanical configuration in which a stage is mounted on a vibration isolation table, a technique of feeding a signal from a stage control unit to the vibration isolation table control unit to suppress a reaction force of the vibration isolation table caused by driving the stage is disclosed. Has been done. Further, in Japanese Patent Laid-Open No. 6-232021, a second acceleration is applied to the table so that the same acceleration as the acceleration of the base acts on the table so that the displacement between the table and the base does not occur even if the table is shaken. It has a driving means. further,
Japanese Unexamined Patent Publication No. 6-280930 discloses a technique that uses both a ground motion feedforward and a feedforward of a driven object in combination with a digital control type active vibration isolator. Not only in these patents, but also in commonly used feedforward, when two driving objects are considered, for example, they are applied to objects having the same motion directions that are moved with respect to each other. That is, when the xy axes are defined in the horizontal plane, x
This is a technique in which the movement of a first driven object that is driven in the axial direction is detected, and this is fed forward to drive the second driven object in the x-axis direction as well.

However, for example, it is possible to detect the movement of the driving object in the x-axis direction and feed forward to the second driving object in the y-axis direction, which has a different degree of freedom in driving. It has not been. That is, the present invention is a feedforward technique for driving objects having mutually controlled degrees of freedom, that is, an XY stage and a fine movement stage, and is distinct from the prior art.

The fact that the XY stage and the fine movement stage mechanically interfere with each other and impedes the improvement of the positioning characteristics of the entire positioning mechanism including them will be shown. Figure 5 is a definitive XY stage when the step driving in the X direction, motion mode deviation signal in the fine movement stage control unit (e _g, eθ _x,
It is the measurement result showing the state of eθ _y ). From the top of the figure,
Vertical translation deviation signal e _g the fine movement stage, x-axis rotational motion deviation signal E.theta _x, y-axis rotational motion deviation signal E.theta _y P and the XY stage controller,
The ID compensation signal X-PID. Where P is proportional and I
Means integral and D means differential action. From the figure, X
During the acceleration / deceleration period of the Y stage, that is, P for step drive
It can be seen that, in accordance with the shake of the ID compensation signal X-PID, the rotational motion deviation signal eθ _y about the y axis causes the swing. The cause of this is obvious. In other words, the rotational moment about the y-axis acts as a torque disturbance on the fine movement stage on the XY stage due to the sudden acceleration / deceleration of the XY stage in the x-axis direction. Where eθ
If the damping of the oscillation of _y is good, that is, if the oscillation of eθ _y occurs only during the step driving period of the XY stage and it disappears immediately before the XY stage reaches the target position, , The overall positioning performance including the XY stage and the fine movement stage is not deteriorated. However, if the gain of the fine movement stage controller is increased in order to shorten the positioning time of the fine movement stage itself, the amplitude of the eθ _y ramp that occurs during step drive gradually increases, and moreover, until it settles. It takes a long time. This state is shown in FIG. 6 by numerical calculation. Since the fluctuation of the deviation signal caused by the application of the torque disturbance around the y-axis is dominated by eθ _y , only this waveform is shown. Here, the magnitude of the torque disturbance is 0.075 [kg
m], and was applied for 0.012 [sec] from 0.01 to 0.13 [sec]. Further, in FIG. 6, when the gain of the thick line is standardized as 1, the thin line is 2,
The dashed line is the response for 2.5. Now, referring to FIG. 6, it can be seen that the amplitude of eθ _y also becomes large as the gain becomes large, and that the time until it settles significantly increases. As described above, the XY stage has to be accelerated and decelerated to be positioned at a desired position. However, when the turbulence of the motion mode deviation signal in the fine movement stage control device caused by the acceleration and deceleration is not rapidly attenuated, Positioning within the desired positioning accuracy is not completed.
In other words, there is a problem in that the stage cannot be moved to the stage of positioning the fine movement stage upon completion of the positioning. Because the reflection mirror of the laser interferometer that obtains the position measurement value necessary for positioning the XY stage is provided on the fine movement stage, and as a result of the fine movement stage being shaken, a positional error is mixed in the XY stage. This is because the stage will be moved.

In the present invention, the signal for step-driving the XY stage is appropriately compensated, and the compensation signal is feed-forwarded to the fine movement stage controller in consideration of the movement mode of the fine movement stage. , The fluctuation of the fine movement stage due to the positioning of the XY stage is compensated to improve the positioning characteristics of the fine movement stage, and by extension, the entire stage positioning control device.

Now, by stepwise driving the XY stage in the x-axis (y-axis) direction, the fine movement stage is rotated around the y-axis (x
It is assumed that a torque disturbance about the axis acts and the torque disturbance disturbs the rotational motion deviation signal eθ _y (eθ _x ) about the y axis (about the x axis) in the fine movement stage controller. That is, it is assumed that the positioning mechanism including the XY stage and the fine movement stage is configured to cause such a phenomenon. Here, a feedforward compensation signal is generated by appropriately frequency-shaping the drive signal of the XY stage, and this compensation signal is added to the fine movement stage control device in consideration of the movement mode of the fine movement stage.
Then, it acts to synchronously suppress the fluctuation of the deviation signal in the fine movement stage control device that occurs in synchronization with the step driving of the XY stage.

[0017]

1 is a block diagram of a stage positioning control apparatus according to an embodiment of the present invention. Horizontal x for simplicity
The case where the fine movement stage shown in FIG. 5 is mounted on the coarse movement stage 19 which is step-driven in the axial direction is shown. Therefore, the coarse movement stage 19 corresponds to the X stage 1 in FIG.

The apparatus of FIG. 1 has a bar mirror 2 on a substrate 9.
The output beam 22 from the laser interferometer 21 is applied to the bar mirror 20 to measure the position of the coarse movement stage 19 in the x-axis direction. This measured value is converted into an electric signal by the position measuring means 23 and compared with the value applied to the control command terminal 24. This comparison output signal passes through the speed compensator 25 or the position compensator 26 and is input to the power amplifier 27. Then, the power amplifier 27 supplies a current to the actuator 28 that drives the coarse movement stage 19. here,
Reference numeral 29 denotes a first switch means, which outputs the output of the speed compensator 25 when the coarse movement stage 19 is in the step driving state for moving the coarse movement stage 19 near the desired position at high speed, and the position compensation when the asymptotic approach to the target position is achieved. The output of the device 26 is selected and input to the power amplifier 27.

As described above with reference to the conventional example shown in FIG. 4, the step drive of the coarse movement stage 19 causes a torque disturbance about the y-axis to act on the substrate 9. Therefore rotational movement deviation signal E.theta _y around the y-axis is mainly violently in the fine movement stage control device, it has to disturb the positioning settling performance of the substrate 9 of the fine movement stage. Not only that, but since the bar mirror 20 for obtaining the position information of the coarse movement stage 19 is provided on the substrate 9, the positioning stability of the coarse movement stage 19 is also deteriorated when the substrate 9 vibrates. Therefore, in the apparatus shown in FIG. 1, the signal applied to the command terminal 24 for step-driving the coarse movement stage 19 is switched only in the speed mode in which the coarse movement stage 19 is rapidly accelerated / decelerated, that is, only in the step driving period. The second that turns on
It is input to the feedforward compensator 31 around the y-axis via the switch means 30 of FIG. Then, the output of the feedforward compensator 31 around the y-axis is added to the output signal of the compensator 15L in the preceding stage of the motion mode distribution circuit 18 in the fine movement stage controller 100. Therefore, it is possible to synchronously suppress the oscillation of the motion mode deviation signal generated in the fine movement stage control device in synchronization with the step drive.

Similarly, when the fine movement stage including the substrate 9 is a coarse movement stage (not shown) in the Y direction, that is, when the Y stage is step-driven in the y axis direction, a torque disturbance about the x axis acts on the substrate 9. The rotational movement deviation signal eθ _x about the x-axis in the fine movement stage controller is swung. At this time, the drive signal for the Y stage is guided to the signal line 32 only during step driving, and then input to the feedforward compensator 33 around the x-axis, and the compensator 3
Compensator 15R in the fine movement stage control device
It may be configured to be added to the output signal of. Note that X
A closed loop composed of position measuring means 21 and 23, a speed compensator 25, a position compensator 26, and a power amplifier 27, which are provided for step-driving the stage to finally position it at a desired position, is similar to the Y stage. Will be referred to as an XY stage control device together with the closed loop.

Next, the effectiveness of the present invention will be shown by numerical calculation. In the conventional fine movement stage controller 100 shown in FIG. 4, motion mode deviation signal when the torque disturbance around the y-axis to the substrate 9 constituting the fine movement stage is applied (e _g,
When eθ _x , eθ _y ) is simulated based on the control model, the results shown in FIG. 7 are obtained. The calculation conditions are the same as in the case of FIG. From the top of FIG. 7, translational motion deviation signal e _g , rotational motion deviation signal e _{θ x} and y around the x-axis are shown.
The rotational movement deviation signal eθ _y about the axis is shown. It can be seen that a response waveform similar to the experimental result shown in FIG. 5 is obtained qualitatively. Next, XY equipped with a fine movement stage
Since the step drive signal to the stage is known, this drive signal is compensated and fed forward to the fine movement stage controller. The results are shown in Fig. 8. The broken line in the figure shows the case without feedforward, and the solid line shows the response with feedforward. Obviously, it can be confirmed that the fluttering of eθ _y can be suppressed well by applying the feed forward. Therefore, the step response of the X stage can suppress the disturbance response around the y-axis generated in the fine movement stage. Similarly, the step drive of the Y stage in the y-axis direction causes a disturbance response around the x-axis in the fine movement stage. This response causes the feedforward compensation signal received from the step drive signal of the Y stage to be transmitted to the fine movement stage controller. This can be suppressed by adding to the control signal cθ _x around the x axis in the preceding stage of the motion mode distribution circuit 18.

Next, a configuration example of a specific compensator for performing feedforward will be shown. Here, for simplification, an example of how to perform feedforward will be described based on a block diagram when a position control system is configured for a fine movement positioning mechanism having one degree of freedom. FIG. 9 is a control block diagram for explaining feedforward to the fine movement stage controller. Where m is mass, d is viscous friction coefficient,
k is a spring constant, k _i is an integrator gain, k _loop is a loop gain, k _s is a position sensor conversion constant, V _com is a command value, V
_s is the position sensor output voltage, x is the displacement, F _F is the feedforward input, and d _d is the disturbance input. When the relationship between V _s , V _com , F _F , and d _d is obtained using the symbols shown in FIG. 9, the formula (1) is obtained by a simple calculation.

[0023]

[Equation 1] Since the effect of input disturbance d _d is on the position sensor output V _s may be suppressed by the input of the feedforward F _F, it is sufficient to configure the feedforward F _F satisfying the expression (2) Relationship I understand. That is, it is sufficient to realize a transfer function having a pseudo differential characteristic.

[0024]

[Equation 2] To realize the equation (2), it is necessary to identify the values of d and k. However, after all, the form of the transfer function showing the relationship between d _d and F _F is

[0025]

(Equation 3) Therefore, it suffices to design the mounting so that both the gain k _ff and the time constant T _ff can be adjusted. That is, even if k and d cannot be accurately identified, there is no difficulty in realizing the feedforward compensator and adjusting it to secure desired performance. The transfer function of the feedforward compensator 31 around the y-axis, which was designed based on the above idea and used in obtaining the numerical calculation of FIG. 8, is as follows.

[0026]

[Equation 4]

The transfer function of the equation (2) having the pseudo-differential characteristic is derived when it is assumed that a step disturbance is applied. However, the gist of the present invention is to perform appropriate frequency shaping on the drive signal of the XY stage and feed the output signal to the fine movement stage control device in consideration of the motion mode. In the above case, this frequency shaping is merely the pseudo-differential characteristic as shown in the equation (3). Therefore, the feedforward compensation is not limited to the pseudo-differential characteristic, and may be any one as long as appropriate frequency shaping is performed according to the pattern of the step drive signal acquired from the XY stage control device and the signal quality thereof.

[0028]

Other Embodiments In the embodiment shown in FIG. 1, a signal for feeding forward into the fine movement stage controller is received from the command terminal 24. However, the signal for feedforward is not limited to the signal at the command terminal 24 without departing from the gist of the present invention. For the signal for feedforward, for example, (1) a vibration sensor for detecting the step driving state in the x-axis direction, for example, an acceleration sensor is attached to the substrate 9 of the coarse movement stage 19 or the fine movement stage, and this output signal is appropriate. Frequency shaping to add to the control signal cθ _y in the fine movement stage control device, or (2) an input signal or output signal to the power amplifier 27, or an arbitrary signal in a closed loop for positioning control of the coarse movement stage 19. It is also possible to detect a signal, perform appropriate frequency shaping, and selectively add it to the control signal cθ _y in the fine movement stage controller only during the step driving period.

In the above embodiment, as shown in FIG. 10, xy with the center of the substrate 9 of the fine movement stage as the origin.
Actuator 10M on the positive side on the y-axis in the coordinate system
, An actuator 10R is arranged on the positive side of the x-axis on the negative side of the y-axis, and an actuator 10L is arranged on the negative side of the y-axis on the negative side of the x-axis, and an XY stage equipped with such a fine movement stage is shown in FIG. An example in which step driving is performed in the x-axis or y-axis direction of the xy coordinate system shown in FIG. Therefore, the torque disturbance around the y-axis mainly acts on the fine movement stage in the step driving in the x-axis direction and the torque disturbance around the x-axis in the step driving in the y-axis direction. The motion mode difference signal of is also eθ _{y in} the step drive in the x-axis direction.
However, in the step drive in the y-axis direction, eθ _x mainly swings. However, the present invention does not depend on such peculiarity of the actuator arrangement. Further, in the above description, the fine movement stage control device adopts the control system configuration of non-interference based on the motion mode, but the present invention does not depend on such a special structure of the control system. Figure 2
FIG. 3 is a block diagram when the present invention is applied to a fine movement stage controller having a normal independent control system structure. 2, constituent elements having substantially the same operations and functions as those of the constituent elements of FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In FIG. 2, the motion mode extraction circuit 17 and the motion mode distribution circuit 18 are removed from the fine movement stage controller shown in FIG. 1, and the position sensors 11M, 11R, and 11L near the actuators 10M, 10R, and 10L are removed. The control loop independent of each axis is constructed by the feedback from the signal. Therefore, the command voltage input terminals 13'M, 13 '
Position target values for each axis are applied to R, 13'L, and deviation signals (e _M , e _R , e _L ) and control signals (c _M , c _R , c _L ) are applied.
) Is also for each axis. Here, the coarse movement stage 19
When is driven stepwise in the x-axis direction, a torque disturbance about the y-axis acts on the substrate 9 of the fine movement stage. However, the signal at the command terminal 24 is compensated for the feedforward compensation about the y-axis only during the step drive. The output signal to a feed-forward signal distribution calculation circuit 34.
Is added to the front stage of the power amplifiers 16M, 16R, 16L for each axis. The feedforward signal distribution calculation circuit 34 receives the output of the feedforward compensator 31 around the y-axis, distributes this signal, and finally generates displacements in the actuators 10R and 10L to resist torque disturbance. That is. Similarly, when the Y-direction coarse movement stage (not shown) is step-driven in the y-axis direction, the signal of the feedforward compensator 33 around the x-axis is guided to the feedforward signal distribution calculation circuit 34, and the x of the substrate 9 is moved.
Actuator 1 so as to resist the torque disturbance around the axis
The output signal of the feedforward signal distribution arithmetic circuit 34 is added to the preceding stage of the power amplifiers 16M, 16R and 16L so as to generate displacement in 0M, 10R and 10L.

Further, according to FIG. 2, even when the fine movement stage actuators 10M, 10R and 10L are arranged other than those shown in FIG.
It can be seen that this can be dealt with by adding a design change to the calculation contents of 4. That is, in the xyz coordinate system of FIG. 10, the actuator 10 is added to a new coordinate system rotated around the z axis.
Even when M, 10R, and 10L are rearranged, and the XY stage, which is a coarse movement stage, is step-driven in the x-axis and y-axis directions in the old coordinate system, respectively, the feed is performed to withstand the torque disturbance during step driving. The operation content of the forward signal distribution operation circuit 34 can be configured.

Although the control device is realized by the analog arithmetic circuit in the embodiments of FIGS. 1 and 2, some or all of them may be replaced by a digital arithmetic device such as an electronic computer.

[0032]

In the past, the XY stage controller and the fine movement stage controller were not associated with each other in the control loop. Therefore, as the positioning performance of the fine movement stage is pursued, even if the control devices are independent of each other, the mechanical interference with the XY stage becomes remarkable, and the overall positioning performance including the XY stage and the fine movement stage cannot be improved. Was there. In the stage positioning control device of the present invention, since the control loops of the XY stage control device and the fine movement stage control device are related to each other, the gain in the fine movement stage control device is set to the maximum in the stable range. Even in this case, it is possible to suppress the settling disturbance of the fine movement stage controller caused by the step driving of the XY stage in synchronization with the step driving. Therefore, there is an effect that the quality of the overall positioning performance is improved.

Further, conventionally, parameter adjustment as a closed loop system for the XY stage control device and the fine movement stage control device was not independent as a result even though the control device was independent. According to this, so-called orthogonal adjustment is possible. That is, since the parameter adjustment for each control device can be performed independently, the work time required for the parameter adjustment can be shortened, which greatly contributes to the shortening of the startup time of the device.

[Brief description of drawings]

FIG. 1 is a block diagram of a stage positioning control device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a stage positioning control device according to another embodiment of the present invention.

FIG. 3 is a schematic diagram of an XY stage mounted on a surface plate.

FIG. 4 is a block diagram of a fine movement stage control device.

FIG. 5 is a motion mode deviation signal in the fine movement stage control device during the XY stage X step drive.

FIG. 6 is a motion mode deviation signal eθ _y when the loop gain is changed in the case where a torque disturbance about the y axis acts on the fine movement stage.

FIG. 7 is a motion mode deviation signal when a torque disturbance about the y axis acts on the fine movement stage.

FIG. 8 is a motion mode deviation signal depending on the presence / absence of feedforward compensation when a torque disturbance about the y-axis acts on the fine movement stage.

FIG. 9 is a control block diagram for explaining feedforward compensation to a fine movement stage controller.

FIG. 10 is a layout diagram of actuators 10M, 10R, and 10L.

[Explanation of symbols]

1: X stage, 2: fine movement stage, 3: silicon wafer, 4: Y stage, 5R, 5L: mover of linear motor, 6R, 6L: coil, 7: stage surface plate, 8: surface plate, 9: substrate , 10M, 10R, 10L: actuator, 11M, 11R, 11L: position sensor, 12M, 1
2R, 12L: displacement amplifier, 13M, 13R, 13L:
Command voltage input terminal, 14M, 14R, 14L: deviation amplifier, 15M, 15R, 15L: gain compensator, 16M,
16R, 16L: power amplifier, 17: motion mode extraction circuit, 18: motion mode distribution circuit, 19: coarse motion stage,
20: bar mirror, 21: laser interferometer, 22: emitted beam, 23: position measuring means, 24: command terminal, 25:
Speed compensator, 26: position compensator, 27: power amplifier, 2
8: Actuator, 29: First switch means, 3
0: second switch means, 31: feedforward compensator around y-axis, 32: signal line, 33: feedforward compensator around x-axis, 34: feedforward signal distribution arithmetic circuit.

Claims (4)

[Claims] 1. An XY stage mounted on a surface plate, which is an anti-vibration device installed on a floor surface, for positioning in a horizontal plane, and a position in the vertical axis direction mounted on the XY stage and an inclination from the vertical axis. A fine movement stage in which an actuator is arranged to control the XY stage, an XY stage control device for positioning the XY stage, and a fine movement stage control device for positioning the fine movement stage. Means for feeding forward a compensation signal, which is obtained by performing frequency shaping according to a motion mode to a step drive signal for positioning the XY stage, to the fine movement stage controller for the step drive period of the XY stage. Stage positioning control device. 2. The feedforward means comprises the X
Switch means for detecting a step drive signal in the Y-stage control device and selecting this drive signal only during a step drive period, and feedforward compensation for applying appropriate frequency shaping to the signal selected by this switch means. And a feedforward circuit for feedforwarding an output signal of the feedforward compensator to the fine movement stage control device in consideration of a motion mode only during a step drive of the XY stage. The described stage positioning control device. 3. The fine movement stage control device is a control device having a decoupling structure based on a motion mode,
The step drive signal in the Y stage control device is a signal applied to the command terminal, the feedforward compensator has a pseudo differential characteristic, and the feedforward circuit has a pseudodifferential characteristic. 3. The output of the above is added to the preceding stage of the motion mode distribution circuit in the fine movement stage controller having the structure of decoupling based on the motion mode.
The described stage positioning control device. 4. The fine movement stage control device is a control device in which a drive axis is constituted by a control loop independent of each axis, and a step drive signal in the XY stage control device is a signal applied to a command terminal, The feed-forward compensator has a pseudo-differential characteristic, and the feed-forward circuit includes the output of the feed-forward compensator having the pseudo-differential characteristic in each of the fine movement stage control devices configured by a control loop independent of each axis. 3. The stage positioning control device according to claim 2, further comprising a feedforward signal distribution calculation circuit for distribution to a front stage of the axial power amplifier.