JP2000077313A - Stage device and exposure device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the control performance of a stage. SOLUTION: A first stage PST has a first part 22 provided with a movable part 16b of a driving mechanism 16 and a second part 19 holding an object P.
Driven in the axial direction. In the control device 11, the first part 19
The position of the object 19 is controlled via the drive mechanism 16 based on the measurement result of the interferometer 24 for measuring the position of the object 19. For this reason, even if mechanical natural vibration occurs between the first part 22 and the second part 19 for some reason, mechanical natural vibration is not generated in the position control system that controls the position of the first stage. Since it is not included as a resonance mode, the response band of the stage control system can be expanded. Therefore, the control performance of the first stage can be improved by avoiding the influence of mechanical natural vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a stage apparatus and an exposure apparatus, and more particularly, to an exposure apparatus used in a lithography process for manufacturing devices such as a liquid crystal display panel, an integrated circuit, and a thin-film magnetic head. The present invention relates to a stage device suitable for an exposure device.

[0002]

2. Description of the Related Art Conventionally, in a lithography process for manufacturing a liquid crystal display panel, an integrated circuit or the like, various exposure apparatuses for transferring a mask pattern onto a substrate have been used. For example, as an exposure apparatus for liquid crystal, a step-and-repeat type static exposure type projection exposure apparatus (a so-called liquid crystal stepper), or a method in which a mask stage and a plate stage are scanned in the same direction with respect to a projection optical system. A projection exposure apparatus such as a batch transfer type scanning exposure apparatus that transfers a mask pattern onto a plate (glass substrate) is mainly used. Recently, in response to the enlargement of the liquid crystal display panel and the accompanying increase in the size of the plate, a single plate is exposed to a plurality of shots in the same manner as a stepper. A step-and-scan type scanning exposure apparatus (scanning stepper) capable of exposure has also been developed.

FIG. 5 shows a scanning exposure apparatus of the above-described batch transfer type (or step-and-scan type) focusing on a stage system. FIG. 6 shows a control unit (controller) of FIG. 2) shows a configuration of a stage control device mainly composed of 101.

In FIG. 5, a mask stage MST and a plate stage PST are supported on an upper surface plate 102a and a lower surface plate 102b constituting a main body column 102 for holding a projection optical system PL via air pads (not shown). Then, they are driven by the linear motors 104 and 106 in the horizontal direction on the paper (hereinafter referred to as “scanning direction”). The stator 104a of the linear motor 104 that drives the mask stage MST includes an upper surface plate 102a
, And the movable element 104b is fixed to the mask stage MS.
Fixed to T. The position of the mask stage MST in the scanning direction is constantly measured by the mask stage position measuring laser interferometer 108 fixed to the main body column 102.

[0005] The stator 106a of the linear motor 106 for driving the plate stage PST is fixed to the lower platen 102b, and the movable member 106b is connected to the plate stage PS.
It is fixed to the bottom of T. Plate stage PST
Is a movable table 11 to which the mover 106b is fixed.
0 and the Z · θ drive mechanism 11
4 is mounted on the substrate table 116. The position of the substrate table 116 in the scanning direction is constantly measured by the plate stage position measuring laser interferometer 112 fixed to the main body column 102.

Next, the mechanism of control of each stage by the stage control device will be described with reference to FIG.

As shown in FIG. 6, an interferometer 112, a subtractor 118, a plate stage servo operation unit 120, a plate stage drive amplifier 122 and this amplifier 122
The position control loop of the plate stage PST is formed by the linear motor 106 driven by the drive signal S2 output from the control unit. Further, the plate stage position information S1 from the interferometer 112 is fed back to the plate stage servo calculation unit 120 via a differentiator (that is, a differentiator) 124, whereby the inner loop (minor loop) of the position control loop is obtained. As a speed control loop. The target position is input from the target value output unit 126 to the subtracter 118 of the position control loop. With the position / speed control loop of the plate stage PST configured as described above, the position / speed control of the plate stage is performed such that the position deviation, which is the difference between the target position and the output of the interferometer 112, becomes zero.

As described above, the interferometer 108 and the subtractor 12
8, mask stage servo operation unit 130, mask stage drive amplifier 132, and linear motor 104 driven by drive signal S4 output from this amplifier 132
Thereby, a position control loop of the mask stage MST is configured. The plate stage position information S1 output from the interferometer 112 is input as a target position to the subtractor 128 of this position control loop. Therefore, the interferometer 11 is controlled by the position control loop of the mask stage MST.
The follow-up control of the mask stage MST with respect to the plate stage PST is performed so that the position deviation, which is the difference between the output S1 of the second stage 2 and the output S3 of the interferometer 108, becomes zero.

[0009]

Generally, in a closed loop control system, the bandwidth (the gain of the closed loop frequency characteristic is √ (1/2) of the low frequency gain at the frequency ω → 0)
Expressed as a frequency that is doubled, expressed in dB gain, a frequency that is 3 dB (decibel) lower than the low frequency gain of ω → 0)
Gives an indication of how many frequency components the system can faithfully follow the input, but in this specification,
Instead of this bandwidth, a frequency at which the gain starts to decrease from a low frequency gain (usually 0 dB) when ω → 0 is defined as a response band (also called a servo response band).

Then, in the stage control system as shown in FIG. 6, for example, the constant speed control (constant speed control) of the plate stage performed at the time of scanning exposure is performed by the response band of the plate stage position / speed control loop. Plate stages such as acceleration / deceleration, settling characteristics, speed irregularity, or acceleration / deceleration settling characteristics, positioning accuracy, etc. for plate stage positioning control performed during shot-to-shot stepping in the case of a step-and-scan exposure apparatus It can be said that the control performance is determined.

However, in the above-described conventional stage control device, the position of the substrate table 116 distant from the linear motor 106 which is a driving source is measured by the interferometer 112. Moving table 1 to which the mover 106b is fixed
10, there is a Z · θ drive mechanism 114 unrelated to the position control of the plate stage in the scanning direction, and mechanical natural vibration having a low frequency is generated in the plate stage position / speed control loop as a resonance mode. included. in this case,
For example, when the natural vibration of the Z · θ drive mechanism 114 occurs during driving of the plate stage, the position information of the substrate table 116 affected by the natural vibration is fed back into the position control loop, Since it becomes difficult to control the position and speed of the stage, it is necessary to prevent such a situation from occurring. For these reasons, in the conventional stage control system, the response band of the position / velocity control loop of the plate stage cannot be sufficiently widened, and as a result, the plate stage control performance is not necessarily sufficiently high. There was an inconvenience of not being able to do so.

FIGS. 7A and 7B show a gain characteristic and a phase in a frequency response characteristic of a position control loop of a plate stage PST in a conventional stage control system when the frequency of the natural vibration is 60 Hz. The characteristics are shown respectively. As is clear from FIG. 7, the response band of the plate stage is about 10 Hz.

Further, as a result of the plate stage control performance not being able to be sufficiently increased, the plate stage PST
Overshoot that occurs after the end of acceleration / deceleration of the system (the response of the system when the input changes suddenly exceeds the expected value; excessive amount), undershoot (the sudden change in the input is the opposite of overshoot) The response of the system does not reach the expected value in the event of the occurrence of an error; that is, the amount of unsatisfactory amount) increases, and the tracking control performance of the mask stage, which is performed using the position of the plate stage as a position command, also deteriorates. Was.

A problem similar to the above-mentioned plate stage is that a two-stage XY stage in which the X stage is mounted on the Y stage via a driving mechanism for the X stage, or a driving mechanism above the coarse movement stage. This can also occur in a control system of a reticle stage having a so-called coarse / fine movement structure in which a fine movement stage is mounted via the same.

The present invention has been made under such circumstances, and a first object of the present invention is to provide a stage control device capable of improving the control performance of a stage.

A second object of the present invention is to provide an exposure apparatus capable of improving throughput and pattern transfer accuracy.

[0017]

A first stage device according to the present invention comprises a first stage (PST) that can move while holding an object (P), and at least a first stage (PST) that moves the first stage.
A stage mechanism having a driving mechanism (16) for driving in a direction, wherein the first stage has a first part (22) having at least a movable part (16b) of the driving mechanism;
A first position measuring device (24) having a second portion (19) for holding the object, and measuring a position of the first portion in a predetermined measurement direction; A first stage control system (L1) for controlling the driving mechanism to control at least the position of the object in the first direction based on the measurement result.

According to this, the first stage has the first portion having at least the movable portion of the driving mechanism and the second portion holding the object, and is driven by the driving mechanism in at least the first direction. It has become. Further, the first stage control system controls the driving mechanism based on the measurement result of the first position measuring device to control at least the position of the object in the first direction.

That is, the first stage control system is based on the position measurement result of the first portion having the movable portion of the drive mechanism, not the position measurement result of the second portion holding the object to be position-controlled. Since the drive mechanism is controlled, for example,
Even if mechanical natural vibration occurs for some reason between the first part and the second part, mechanical natural vibration is not included as a resonance mode in the first stage control system.
As a result, the response band of the first stage control system can be expanded. Therefore, the control performance of the stage (first stage) can be improved while avoiding the influence of mechanical natural vibration.

Here, "the first portion having at least the movable portion of the drive mechanism" means that the first portion of the stage is constituted by the movable portion of the drive mechanism, and that the first portion and the movable portion are different from each other. It is a member, and includes any case where the movable portion is fixed to the first portion. Therefore, the first
The measuring point of the measuring device may be set to either the movable part or the separate member.

The measuring direction of the first position measuring device is as follows:
It is desirable that the direction coincides with the first direction,
A direction other than this (however, a direction orthogonal to the first direction is excluded) may be used. Even in such a case, the position of the first portion in the first direction can be obtained by the trigonometric function operation (the same applies to a second position measurement device described later).

In the first stage apparatus, the second stage for measuring the position of the second portion in a predetermined measurement direction is provided.
When the first stage control system (L1) is provided with the position measuring device (25), the first portion (22)
The drive mechanism (16) is further controlled based on the measurement results of the first and second position measuring devices (24, 25) so as to compensate for a positional error between the first and second portions in the first direction. You may. In such a case, the first stage control system
The drive mechanism is further controlled based on the measurement results of the first and second position measuring devices so as to compensate for an error in the position of the portion and the second portion in the first direction. The object held thereby can be accurately positioned at a desired position.

The first portion and the second portion constituting the first stage may be composed of separate members and may be connected to each other with a certain degree of freedom. The two parts may be formed integrally. The term “integrally formed” includes both the case where the same member is integrally formed and the case where separate members are firmly fixed to each other.

Further, the second stage device according to the present invention is the first stage device, wherein a second stage (MST) different from the first stage (PST) and a second stage (19) are provided. A second position measurement device (25) for measuring a position in a predetermined measurement direction; and the first stage and the second stage based on a measurement result of the second position measurement device.
A second stage control system (L2) for controlling the second stage so that the stage has a predetermined positional relationship.

According to this, since the position control performance of the first stage can be improved by the first stage device, the position error caused by overshoot and undershoot after the end of acceleration / deceleration of the first stage can be reduced. Can be smaller. For this reason, an error included in the measurement result of the position of the second portion in the predetermined measurement direction by the second position measurement device is reduced, and the error of the first stage performed based on the measurement result of the second position measurement device is reduced. The control performance of the second stage for adjusting the positional relationship of the second stage is improved.

A first exposure apparatus according to the present invention is an exposure apparatus for transferring a predetermined pattern onto a substrate (P), comprising the first stage device, and a first stage (P)
The substrate is placed on the second portion (19) of (ST).

According to this, as described above, the control performance of the first stage can be improved by expanding the response band by the first stage device, and as a result, it is mounted on the second portion of the first stage. It is possible to improve the positioning settling time and the positioning accuracy of the substrate. Therefore, both improvement in throughput and improvement in pattern transfer accuracy can be achieved.

A second exposure apparatus according to the present invention is an exposure apparatus for transferring a mask pattern onto a substrate by synchronously moving a mask (M) and a substrate (P). The first stage and the second stage
One of the stages is a mask stage (MST) on which the mask is mounted, and the other is a substrate stage (PST) on which the substrate is mounted.

According to this, in the second stage apparatus, the position control performance of the first stage by the first stage control system can be improved, and the second stage control system can control the position of the first stage with respect to the first stage. The control performance of the second stage for adjusting the positional relationship between the two stages can be improved. Therefore, when one of the first stage and the second stage is a mask stage on which a mask is mounted, and the other is a substrate stage on which a substrate is mounted, the mask stage and the substrate stage at the time of scanning exposure are different from each other. Synchronous settling time and constant-speed synchronous control can be performed with higher accuracy. As a result, it is possible to improve the throughput and the overlay accuracy (pattern transfer accuracy) between the mask and the substrate.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG. FIG. 1 schematically shows a configuration of an exposure apparatus 10 according to one embodiment. The exposure apparatus 10 includes a mask M on which a liquid crystal display element pattern is formed.
And a glass plate (hereinafter, referred to as a “plate”) P as a substrate (and an object) held on a plate stage PST as a first stage with respect to a projection optical system PL in a first direction, that is, a predetermined scan. The pattern formed on the mask M is transferred onto the plate P by relatively scanning in the same direction at the same speed along the direction (here, the Y-axis direction in FIG. 1 (the left-right direction in the drawing)). This is a double batch transfer type scanning exposure apparatus for liquid crystal.

The exposure apparatus 10 uses an exposure illumination light IL to expose a predetermined slit-shaped illumination area (X in FIG. 1) on the mask M.
An illumination system IOP for illuminating a rectangular area or an arc-shaped area elongated in an axial direction (a direction perpendicular to the paper surface), and a second system that moves in the Y-axis direction while holding a mask M on which a pattern is formed.
A mask stage MST as a stage, a projection optical system PL for projecting the illumination light IL for exposure transmitted through the above-described illumination area portion of the mask M onto the plate P, and a Y holding the plate P
The apparatus includes a main body column 12 that supports the plate stage PST that moves in the axial direction, the mask stage MST, and the plate stage PST and that holds the projection optical system PL, and a control device 11 that controls the two stages MST and PST.

The illumination system IOP is disclosed, for example, in JP-A-9-3
As disclosed in Japanese Unexamined Patent Publication No. 200956, the light source unit, a shutter, a secondary light source forming optical system, a beam splitter, a condenser lens system, a field stop (blind), an imaging lens system, and the like (all not shown). The slit-shaped illumination area on the mask M mounted and held on the mask stage MST described below is illuminated with uniform illuminance.

The mask stage MST is formed by an upper surface plate 12 constituting a main body column 12 by an air pad (not shown).
It is levitated and supported above the upper surface of a through a clearance of about several microns, and is driven in the Y-axis direction by a driving mechanism 14.

Since a linear motor is used as the drive mechanism 14 for driving the mask stage MST, this drive mechanism is hereinafter referred to as a linear motor 14.
The stator 14a of the linear motor 14 is
a and is extended along the Y-axis direction. The mover 14b of the linear motor 14 is fixed to the mask stage MST. The position of the mask stage MST in the Y-axis direction is determined by a mask stage position measuring laser interferometer (hereinafter, referred to as “mask interferometer”) 18 fixed to the main body column 12 with reference to the projection optical system PL. It is always measured at a resolution, for example, a resolution of about several nm. The Y position information S3 of the mask stage MST measured by the mask interferometer 18 is supplied to the control device 11 (see FIG. 2).

The projection optical system PL is arranged below the upper surface plate 12a of the main body column 12, and is held by a holding member 12c constituting the main body column 12. As the projection optical system PL, one that projects an erect erect image at the same magnification is used here. Accordingly, when the slit-shaped illumination area on the mask M is illuminated by the exposure illumination light IL from the illumination system IOP, an equal-magnification image (partial erect image) of the circuit pattern in the illumination area is formed on the plate P. The image is projected onto a region to be exposed conjugate to the illumination region.
For example, as disclosed in Japanese Patent Application Laid-Open No. 7-57986, the projection optical system PL may be constituted by a plurality of sets of equal-size erect projection optical system units.

The plate stage PST is arranged below the projection optical system PL, and floats above the upper surface of the lower platen 12b constituting the main body column 12 through a clearance of about several microns by an air pad (not shown). Supported. The plate stage PST is driven in the Y-axis direction by a linear motor 16 as a driving mechanism. The stator 16a of the linear motor 16 is fixed to the lower surface plate 12b and extends along the Y-axis direction.
Further, a mover 16b as a movable portion of the linear motor 16
Is fixed to the bottom of the plate stage PST.

The plate stage PST includes a moving table 22 as a first part to which the mover 16b of the linear motor 16 is fixed, a Z · θ driving mechanism 20 mounted on the moving table 22, a substrate table 19 as a second part mounted on the upper part of the θ drive mechanism 20. A plate P is placed on the substrate table 19, and is fixed by suction via a vacuum chuck (not shown). Further, the substrate table 19 has a value of Z · θ.
The drive mechanism 20 is adapted to be minutely driven in the vertical and rotational directions.

The position of the moving table 22 in the Y-axis direction is determined by a first plate interferometer 24 as a first position measuring device fixed to the main body column 12 at a predetermined resolution with reference to the projection optical system PL. For example, it is always measured with a resolution of about several nm. Y position information S0 of the moving table 22 measured by the first plate interferometer 24
Are supplied to the control device 11 (see FIG. 2).

The position of the substrate table 19 in the Y-axis direction is determined by a second plate interferometer 25 as a second position measuring device fixed to the main body column 12 with respect to the projection optical system PL. It is always measured at a resolution, for example, a resolution of about several nm.

In this case, the second plate interferometer 25 has two Y-axis directions separated by a predetermined distance L in the X-axis direction (perpendicular to the plane of FIG. 1) orthogonal to the Y-axis direction. A two-axis interferometer that irradiates a long beam to the substrate table 19 is used, and the measured values of each measurement axis are supplied to the control device 11 (and a main control device (not shown) via the control device). . Assuming that the measurement values of the respective measurement axes of the second plate interferometer 25 are Y1 and Y2, Y = (Y1 + Y
The position of the substrate table 19 in the Y-axis direction can be obtained by 2) / 2, and the rotation amount of the substrate table 19 around the Z-axis can be obtained by θ = (Y1−Y2) / L. In the following description, It is assumed that the Y is output from the second plate interferometer 25 as the Y position information S1 of the substrate table 19 unless otherwise required.

Further, in this embodiment, the Z of the plate P
A focus position detection system (not shown) for measuring the directional position, for example, an oblique incident light type focus position detection system is fixed to a holding member 12c for holding the projection optical system PL. The Z position information is supplied to a main controller (not shown). The main controller, for example, projects the Z position of the plate P via the Z · θ driving mechanism 20 based on the Z position information during scanning exposure. An autofocus operation for matching the image plane of the system PL is performed. The main controller controls the rotation of the plate P during scanning exposure through the Z · θ drive mechanism 20 based on the above θ (the amount of rotation about the Z axis), or controls the mask M and the plate P The rotation of the plate P is controlled via the Z · θ drive mechanism 20 based on the rotation error between the two obtained from the alignment result.

FIG. 2 is a block diagram of a stage control device mainly constituted by the control device 11, and FIG. 3 is a control block diagram of a control system equivalent to the stage control device. .

The control device 11 outputs a target position P _ref , a command speed V _ref , and a command acceleration α _ref to a target value output unit 26.
And the target position P output from the target value output unit 26.
a subtractor 28 for calculating a difference (positional deviation) between _ref and the Y position information S0 output from the first plate interferometer 24, that is, the current position of the moving table 22 in the Y-axis direction; Of the plate stage servo operation unit 32 to which the output of the plate stage and the command speed V _ref input by the feedforward input from the target value output unit 26 are input, and the feedforward input from the output of the plate stage servo operation unit 32 and the target value output unit 26 An adder 55 for adding a control amount corresponding to the command acceleration α _ref to be inputted, and the adder 55
Is converted into a plate stage drive signal S2 and supplied to the linear motor 16 by a plate stage drive amplifier 36
And a differentiator 40 for subtracting the position information S0 and inputting the difference to the plate stage servo calculator 32. The differentiator 40 obtains the time change rate of the position information S0, that is, the speed of the movement table 22, by dividing the difference between the value at the previous sampling and the value at the current sampling by the sampling clock interval.

Further, the control device 11 inputs the Y position information S1 output from the second plate interferometer 25 and the Y position information S3 output from the mask interferometer 18, and calculates the difference between the two. Substrate table 19 and mask stage MST
Subtractor 44 for calculating a positional deviation in the Y-axis direction from the above, a mask stage servo calculator 46 to which an output from the subtracter 44 is input, and a mask stage servo calculator 46
And a mask stage drive amplifier 48 which converts the output of the above into a mask stage drive signal S4 and supplies the output to the linear motor 14.

The plate stage servo operation section 32
As shown in FIG. 3, for example, as shown in FIG. 3, a P controller 50 that performs a (proportional) control operation using a position deviation from the subtractor 28 as an operation signal, a speed command value output from the P controller 50 and a P command shown in FIG. A subtracter 52 that calculates an output of the integrating circuit 56 of FIG. 3 corresponding to the output of the differentiator 40, that is, a speed deviation that is a difference from the current speed of the moving table 22.
And an adder 53 that adds the output of the subtracter 52 and the command speed _Vref that is fed forward from the target value output unit 26. The speed deviation that is the output of the adder 53 is used as an operation signal (proportional + P) for performing a control operation combining the control operation (PI control operation) and the phase lead compensation control
And an I controller 54.
The PI controller 54 has a built-in phase lead compensation circuit, for example, a CR circuit.

In this embodiment, the first plate interferometer 24, subtractor 28, differentiator 40, plate stage servo operation unit 32, plate stage drive amplifier 36 and linear motor 16 shown in FIG. And a speed control for performing a control operation in which the PI control operation and the phase lead compensation control which constitute the inner loop (minor loop) of the position control loop LL1 for performing the proportional control of the position of the plate stage PST are performed. A multi-loop control system L1 having a loop LL2 is configured. The multi-loop control system L1 forms a plate stage position / speed control system L1 as a first stage control system. The reason why the plate stage position / speed control system L1 is a multi-loop control system is, for example, to improve a steady-state speed deviation.

The mask stage servo operation section 46 comprises:
For example, as shown in FIG. 3, it can be configured by a PI controller that performs a PI control operation using a position deviation from the subtractor 44 as an operation signal.

In the present embodiment, the mask interferometer 18, the subtractor 44, the mask stage servo calculator 46, the mask stage drive amplifier 48, and the linear motor 14 shown in FIG. A mask stage position control system L2 is configured as a second stage control system that performs position control of the mask stage MST by regarding the Y position information S1 of the substrate table 19 from the plate interferometer 25 as a target value. The mask stage position control system L2 controls the mask stage MST to follow the plate stage PST using the Y position information S1 of the substrate table 19 as a target input.
For the same reason as described above, the control system of the mask stage may be a multi-loop control system like the plate stage position / speed control system L1.

Further, in this embodiment, as shown in FIG. 2, the position of the substrate table 19 and the position of the moving table 22 are stored in the control device 11 based on the position information S1 and the position information S0. A calculation unit 38 is provided for calculating a difference (error) and calculating a command value for compensating the error.
The output of the arithmetic unit 38 is output via the switch circuit 42
It is connected to an adder 30 arranged between the subtractor 28 and the plate stage servo operation unit 32. The switch circuit 42 is normally off (OFF), and is turned on (ON) by a main controller (not shown) as necessary.
When this switch circuit 42 is turned on, the operation unit 3
In step 8, the difference between the position of the substrate table 19 and the position of the moving table 22 is integrated, and the integrated value is used as a correction value (a command value for compensating the error) as described above for the plate stage position / speed control system L1 (specifically). Specifically, the position control loop L
Feed forward input to L1). That is, the arithmetic operation unit 38 and the switch circuit 42 allow the substrate table 19
A compensation system C1 for compensating for a difference (error) between the position of the moving table 22 and the position of the moving table 22 is configured.

It is needless to say that the control device 11 may be constituted by a microcomputer, and the function of each unit in FIG. 2 may be realized by software or firmware of the microcomputer.

Here, a specific control operation of the above-described plate stage position / speed control system L1 will be described with reference to FIG. 3 while appropriately referring to FIG. Here, it is assumed that the switch circuit 42 is off.

From the target value output unit 26 to the plate stage P
When the signal of the ST target position _Pref is output, the subtractor 2
8, a position deviation which is a difference between the target position _Pref and the Y position information S0 from the first plate interferometer 24 is calculated.
0 performs a proportional control operation, and as a result, the P controller 5
From 0, the speed command value is given to the subtractor 52. Subtractor 5
2, the speed command value and the current speed of the moving table 22 which is the output of the integration circuit 56 in FIG. 3 (actually, the previous sampling value of the position of the moving table 22 calculated by the differentiator 40 in FIG. Calculate the speed deviation, which is the difference between the speeds of the moving table obtained from the difference between the sampling values,
The adder 53 adds the speed deviation and the command speed _Vref, and the PI controller 54 performs a control operation combining the PI control operation and the phase advance compensation control with the speed deviation to which the command speed _Vref is added as an operation signal. As a result, a predetermined thrust command value (control amount) is output from the PI controller 54 to the adder 55. In the adder 55, the command acceleration α _ref has a gain M _P / K1 (this is the plate stage P
Converted thrust command value by the action of a gain) equivalent mass M _P of ST to a value obtained by dividing the thrust conversion gain K1 to be described later (the control amount) is input. Then, the adder 55 adds the output from the gain _MP / K1 and the output of the plate stage servo operation unit 32. And
The control amount (thrust command value) which is the output of the adder 55 is converted into the force F by the thrust conversion gain K1. This force F
As is clear from FIG. 3, the thrust conversion value of the output of the plate stage servo calculation unit 32 and the target value output unit 26
_Is equivalent to the sum of the thrust conversion values (M _P · α _ref ) of the command acceleration α _ref input feed-forward.

Here, the correspondence between the operation of the thrust conversion gain K1 and the actual phenomenon will be described. The thrust command value from the adder 55 is given to the plate stage drive amplifier 36 in FIG. Is applied to the linear motor 16 and the linear motor 16 generates a thrust F.

Then, the plate stage PST is driven in the Y-axis direction at an acceleration α corresponding to the thrust (F). This phenomenon of driving the plate stage PST is equivalent to the fact that the thrust F is converted into the acceleration α by the action of the gain (1 / M _P ) corresponding to the reciprocal of the mass of the plate stage PST. . In this sense,
FIG. 3 shows the gain (1 / M _P ) as a component of the control system.

The acceleration α is calculated by the integration circuit 5
The speed and position are sequentially converted in steps 6 and 58, the speed information is fed back to the subtractor 52, and the position information S0 is fed back to the subtractor 28. Thus, the plate stage position / speed control loop L1
The target position _Pref and the first plate interferometer 2
The position / speed control of the plate stage PST is performed such that the position deviation, which is the difference from the position information S0 from position No. 4 becomes zero.

As described above, in the present embodiment, in addition to the target position P _ref , the command speed V _ref and the command acceleration α _ref are represented by:
Feedforward input is made to the plate stage position / speed control system L1 (see FIG. 3). This is because, in addition to the feedback loop of the position of the plate stage, the speed and the acceleration are fed forward and the plate stage P
By controlling ST, the frequency characteristics of the entire system including the plate stage PST are improved, and the controllability of the plate stage PST by the control device 11, for example, the position control response is further improved.

It should be noted that the integrating circuits 56 and 58 of FIG. 3 do not actually exist, the speed signal output from the integrating circuit 56 is the output of the differentiator 40, and the output S0 of the integrating circuit 58 is The output of 24 is shown in FIG. 3, but the integration circuits 56 and 58 are shown in accordance with the convention of writing a control block diagram.

Next, the mask stage position control system L2
Will be described based on FIG. 3 with reference to FIG. 2 as appropriate.

When the position information S1 is input from the second plate interferometer 25 to the subtractor 44, the subtractor 44 calculates a position corresponding to the difference between the position information S1 and the Y position information S3 from the mask interferometer 18. Calculate the deviation. Next, the PI controller 46 performs a PI control operation using the position deviation as an operation signal, and as a result, a predetermined control amount (a control amount corresponding to the mask stage drive signal S4 in FIG. 2) is output from the PI controller 46. . Then, this control amount is converted into a force F ′ by the thrust conversion gain K2. The correspondence between the operation of the thrust conversion gain K2 and the actual phenomenon will be described.
A predetermined control amount is given from the controller 46 to the mask stage drive amplifier 48 in FIG. 2, and the mask stage drive signal S4 from the amplifier 48 is given to the linear motor 14 so that the linear motor 14 generates a thrust F ′. Is equivalent to

Then, mask stage MST is driven in the Y-axis direction at an acceleration β corresponding to the thrust (F ′). This phenomenon of driving the mask stage MST, in other words, is equivalent to the fact that the thrust F ′ is converted into the acceleration β by the action of the gain (1 / M _M ) corresponding to the reciprocal of the mass of the mask stage MST. is there. In this sense, FIG. 3 shows the gain (1 / _MM ) as a component of the control system.

Then, the acceleration β is calculated by the integrating circuit 6
The position information S3 is sequentially converted into speed and position at 0 and 62, and the position information S3 is fed back to the subtractor 44. In this way, the position information S1 from the second plate interferometer 25 is transmitted by the mask stage position control loop L2. The follow-up control of the mask stage MST with respect to the plate stage PST is performed such that the position deviation, which is the difference between the position information S3 from the mask interferometer 18 and the position information S3 becomes zero.

In the exposure apparatus 10 of the present embodiment, at the time of scanning exposure, a constant speed control of the plate stage PST and a follow-up control of the mask stage with respect to the plate stage PST are performed by a stage control device equivalent to the control system of FIG. , Based on the target position from the target value output unit 26 (corresponding to the acceleration / deceleration command).

In this case, since the Y position information S0 of the moving table 22 from the first plate interferometer 24 is input to the plate stage position / speed control system L1 as the position information of the plate stage, Z・ Θ drive mechanism 2
0, the movement table 22 and the substrate table 19
Even if mechanical natural vibration occurs between the above and the above, since the natural vibration is not included as a resonance mode in the plate stage position / speed control system L1, the servo response band can be expanded. As a result, the plate stage control performance can be improved.

FIGS. 4A and 4B show gain characteristics and phase characteristics in the frequency response characteristics of the stage control device according to the present embodiment obtained by simulation results in which the frequency of the natural vibration is 60 Hz. (Board diagrams) are shown.

In FIG. 4A, reference symbol G1 (f) is
A symbol G indicates a gain characteristic indicating a response of the system to a target position (input) when the measurement value of the interferometer 24 is output.
2 (f) is a case where the measurement value of the interferometer 25 is output.
5 shows a gain characteristic indicating a response of the system to a target position (input). Also, in FIG. 4B, reference numerals P1 (f), P1 (f)
2 (f) shows phase characteristics corresponding to G1 (f) and G2 (f) in FIG. 4 (A), respectively.

As can be seen from G2 (f) in FIG.
In the present embodiment, the servo response band is about 20 Hz, and when compared with the gain characteristic of FIG.
In the present embodiment, it can be seen that the response band of about 10 Hz is expanded.

That is, in the present embodiment, the response band is expanded, and the system can accurately follow the input up to higher frequency components as compared with the conventional example. As a result, the settling time for the target scanning speed of the plate stage is consequently settled. Can be shortened. In other words, if the same time is set as the settling time, the target scanning speed of the plate stage PST can be further increased.

Further, by expanding the response band, the overshoot and the undershoot after the end of the plate stage acceleration / deceleration can be reduced.
The follow-up control performance of the mask stage MST with respect to the plate stage PST performed by the mask stage position control loop L2 with the position 9 as the target value is also improved. Therefore, it is possible to shorten the settling time of the constant speed synchronization between the plate stage PST and the mask stage MST for scan exposure, or to increase the scanning speed of both stages MST and PST, and as a result, the throughput can be improved. . Furthermore, the control performance of the plate stage PST and the follow-up performance of the mask stage MST with respect to the plate stage PST are improved. As a result, even during the constant speed control period of both stages during exposure, constant speed control of both stages is performed in a state closer to ideal. This makes it possible to improve the overlay accuracy of the mask and the plate, and to improve the pattern transfer accuracy, that is, the exposure accuracy.

In the present embodiment, in order to realize the position control of the plate stage PST by controlling the position of the moving table 22, strictly speaking, the position of the substrate table 19 and the position of the moving table 22 are changed. Although the displacement occurs, during the scanning exposure, the plate stage constant speed control based on the projection optical system PL, and the follow-up control of the mask stage with respect to the plate stage,
Since the synchronous control between the mask and the substrate is realized, no inconvenience occurs as a result.

For example, when strict positioning control of the plate stage PST is required at the time of alignment or the like, the compensation system C1 is configured by a main controller (not shown) after the deceleration in the latter half of the movement of the plate stage PST. When the switch circuit 42 is turned on, the difference between the substrate table position and the moving table position is time-integrated by the calculation unit 38, and the integrated value is feed-forward input to the position control loop LL1 of the plate stage as a correction value. Substrate stage 1 instead of moving table 22
9 can be accurately stopped at the target position Pref.

The illumination optical system and the projection optical system composed of a plurality of lenses are incorporated in the exposure apparatus main body for optical adjustment, and a mask stage and a plate stage composed of many mechanical parts are attached to the exposure apparatus main body for wiring. And pipe connection, and further comprehensive adjustment (electrical adjustment, operation check, etc.)
By doing so, the exposure apparatus of the present embodiment can be manufactured. It is desirable to manufacture the exposure apparatus in a clean room in which the temperature, the degree of cleanliness, and the like are controlled.

In the above embodiment, the case where the present invention is applied to a unit-size batch transfer type scanning exposure apparatus for liquid crystal has been described. However, the present invention is not limited to this, and a step-and-repeat type liquid crystal stepper can be used. The present invention can be suitably applied not only to a scanning stepper for a liquid crystal of a step-and-scan method, but also to an exposure apparatus such as a stepper for manufacturing a semiconductor or a scanning stepper. Further, the present invention can also be applied to a vertical exposure apparatus that holds the mask M and the plate P along the vertical direction.

As described above, according to the stage apparatus according to the present invention, the position control performance of the substrate stage can be improved. Therefore, the present invention is particularly applicable to a sequentially moving exposure apparatus such as a stepper or a scanning stepper. Is applied, it is possible to improve the throughput and the positioning performance even when stepping between shots or moving to an alignment position. In particular, in order to improve the positioning performance of the substrate stage, it is desirable to provide a compensation system similar to the compensation system C1 in the above embodiment.

In addition to the above, the present invention also relates to an exposure apparatus such as an electron beam exposure apparatus or an X-ray exposure apparatus, or an apparatus having a substrate stage for holding and moving a substrate, such as a laser repair apparatus. The stage device is applicable.

[0075]

As described above, according to the first to third aspects of the present invention, there is an effect that the control performance of the stage can be improved by avoiding the influence of mechanical natural vibration.

Further, according to the invention described in claim 4, there is an effect that the control performance of the second stage for adjusting the positional relationship of the second stage with respect to the first stage can also be improved.

According to each of the fifth and sixth aspects of the present invention, there is an excellent effect that the throughput and the pattern transfer accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a configuration of an exposure apparatus according to an embodiment.

FIG. 2 is a block diagram illustrating a configuration of a stage control device mainly including the control device of FIG. 1;

FIG. 3 is a control block diagram showing a control system equivalent to the stage control device of FIG. 2;

FIGS. 4A and 4B show the natural vibration frequency of 60H.
FIG. 9 is a Bode diagram showing gain characteristics and phase characteristics in the frequency response characteristics of the stage control device according to the present embodiment, obtained as a result of simulation with z.

FIG. 5 is a view schematically showing a configuration of a conventional exposure apparatus.

FIG. 6 is a block diagram showing a configuration of a conventional stage control device.

FIGS. 7A and 7B show the natural vibration frequency of 60H.
FIG. 9 is a Bode diagram showing gain characteristics and phase characteristics in frequency response characteristics of a conventional stage control system (specifically, a position control loop of a plate stage) when z is set.

[Explanation of symbols]

10 exposure apparatus, 16 linear motor (drive mechanism), 1
6b: mover (movable part), 19: substrate table (second part), 22: moving table (first part), 24: first plate interferometer (first position measuring device), 25: second 2
Plate interferometer (second position measuring device), PST ...
Plate stage (first stage), L1 ... Plate stage position / speed control system (first stage control system), M
ST: mask stage (second stage), L2: mask stage position control system (second stage control system), P: plate (object, substrate), M: mask.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/30 515G 516B F-term (Reference) 2F078 CA02 CA08 CB02 CB05 CB09 CB12 CC07 CC11 CC15 5F031 CA05 CA07 JA02 KA06 LA08 MA27 5F046 AA23 BA05 CC01 CC02 CC03 CC05 CC06 CC08 CC10 CC16 CC18 DA06 DA07 DA08 DB05

Claims (6)

[Claims] 1. A stage device comprising: a first stage capable of holding an object and being movable; and a driving mechanism for driving the first stage in at least a first direction, wherein the first stage is movable by the driving mechanism. A first portion having at least a portion, a second portion holding the object,
And a first position measuring device that measures a position of the first portion in a predetermined measuring direction; and a position of the object in at least the first direction based on a measurement result of the first position measuring device. And a first stage control system for controlling the driving mechanism in order to control the stage mechanism. And a second position measuring device for measuring a position of the second portion in a predetermined measurement direction, wherein the first stage control system is configured to control the first portion and the second portion.
2. The drive mechanism according to claim 1, wherein the drive mechanism is further controlled based on a measurement result of the first and second position measurement devices to compensate for a position error in the first direction with respect to a portion. 3. Stage equipment. 3. The stage device according to claim 1, wherein the first portion and the second portion are formed integrally. 4. A second stage different from the first stage, a second position measuring device for measuring a position of the second portion in a predetermined measuring direction, and a measurement result of the second position measuring device. 2. The control device according to claim 1, further comprising: a second stage control system that controls the second stage such that the first stage and the second stage have a predetermined positional relationship based on the first stage and the second stage. 3. Stage equipment. 5. An exposure apparatus for transferring a predetermined pattern onto a substrate, comprising: the stage device according to claim 1, wherein the substrate is provided on the second portion of the first stage. An exposure apparatus, on which is mounted. 6. An exposure apparatus for transferring a pattern of the mask onto a substrate by synchronously moving a mask and a substrate, comprising the stage device according to claim 4, wherein the first stage and the second stage are provided. One is a mask stage on which the mask is mounted, and the other is a substrate stage on which the substrate is mounted.